🔙 Quay lại trang tải sách pdf ebook Giáo trình ký sinh trùng và bệnh ký sinh trùng thú y Ebooks Nhóm Zalo DAI HOC THAI NGUYEN TRUdNG DAI HOC NONG LAM PGS.TS. N g u y in Thi Kim Lan AT BANNING NGHIEP DAI HOC THAI NGUYEN TRU’O’NG DAI HOC NONG LAM PGS. TS. NGUYEN THI KIM LAN KY SINH TRUNG VA BENH KY SINH TRUNG THU Y (Giao trinh dung cho dao tao bac Dai hgc) NHA XUAT BAN NONG NGHIEP Ha N91 - 2012 MUC LUC • • LCJI NOI DAU 9 m o d A u 11 1. Djnh nghia va noi dung mon hoc 11 2. Moi quan he giua mon ky sinh trung thu y vai cac mon hoc khac 12 3. Gioi thieu noi dung giao trinh ky sinh trung thu y 13 Phan thtf nhat. OAI CU0NG V E KY SINH TRUNG VA BENH KY SINH TRUNG THU Y 15 Chuxrng 1. DAI CLTOHVG VE KY SINH TRUNG THU Y 15 1. Ky sinh trung va ky chu 15 2 . Bac diem doi song ky sinh cua ky sinh trung 18 3. Anh huong qua lai giua ky sinh trung va ky chu 26 Chuomg 2. DAI ClTONG VE BENH KY SINH TRUNG THU Y 29 1 . Khai niem ve benh ky sinh trung thu y, quy dinh cach goi ten benh ky sinh trung 29 2. Mien djch trong benh ky sinh trung 30 3. Tac hai cua benh ky sinh trung doi voi sue khoe dong vat va nang suat chan nuoi 3 3 4. Bien phap phong tri benh ky sinh trung 35 5. Dich te hoc benh ky sinh trung va hoc thuyet diet tru benh giun san 38 Phan thuf hai. GIUN SAN KY SINH VA BENH GIUN SAN d GIA SUC. GIA CAM 45 Chuffng 3. DAI CI/ONG VE GIUN SAN VA BENH GIUN SAn 6 GIA SUC, GIA CAM 45 1. KHAI NIEM VA PHAN LOAI GIUN SAN 45 1.1. Nganh san dep (Plathelminthes) 45 1.2. Nganh giun tron (Nemathelminthesj 45 1.3. Nganh giun dau gai (Acanthocephales) 45 1.4. Nganh Anelides 45 1.5. Nganh Vermides 46 2. KHAl NIEM VA PHAN LOAI BENH GIUN SAN 46 2.1. Khai niem 46 2.2. Phan loai benh giun san 46 3 . p h l t o n g p hA p c h A n d o An b e n h g i u n sA n 4 7 3 3.1. Chan doan doi voi gia sue, gia cAm s6 ng 47 3.2. Chan doan d6 i voi gia sue, gia cam da ch8 t 57 Chuang 4. SAN LA VA MOT SO BENH SAn l A 59 1. DAC DIEM HINH THAl, CAu TAO VA VONG D ^I CUA SAN l A 59 1.1. Dac diem hinh thai, cau tao 59 1.2. Vong doi cua san la 61 2. BENH SAN LA THLTdNG GAP 6 GIA SUC, GIA CAM 62 2.1. Benh san la gan o sue vat nhai lai (Fasciolosis) 62 2.2. Benh san la ruot Ion (Fasciolopsiasis) 70 2.3. Benh san la da eo (Paramphistomatidosis) 74 2.4. Benh san la tuyen tuy (Eurytremosis) 79 2.5. Benh san la o co quan sinh san gia cam (Prosthogonimosis) 83 2.6. Benh san la ruot gia cam (Echisnostomosis) 87 Chuang 5. SAN d Ay VA MOT SO BENH SAN d Ay 91 1. DAC DIEM HINH THAl, CAU TAO, VONG DCJI VA PHAN LOAI sAn d a y 91 1.1. Dac diem hinh thai, cau tao san day 91 1.2. Vong doi 93 1.3. Phan loai san day, cac loai au trung san day gay benh cho vat nuoi 94 2. BENH SAN DAY THUC)NG GAP 0 GIA SUC, GIA CAM 97 2.1. Benh san day Moniezia o gia sue nhai lai (Monieziosis) 97 2.2. Benh san day o ngua 103 2.3. Benh san day a ga 105 2.4. Benh san day o cho va meo 111 2.5. Benh gao Ion 115 2.6. Benh gao bo 120 2.7. Benh au san co nho 123 2.8. Benh au san nhieu dau 127 2.9. Benh ken nuoc 129 Chuong 6. GIUN TRON VA MOT SO BENH GIUN TRON 134 1. DAI CUONG VE GIUN TRON KY SINH 134 1.1. Dac diem hinh thai, cau tao 134 1.2. Vong doi 136 2. CAC BENH GIUN DUA 138 2.1. Benh giun dua Ion (Ascariosis) 138 2.2. Benh giun dua be, nghe (Neoascariosis) 144 2.3. Benh giun dua ngua (Parascariosis) 148 2.4. Benh giun dua ga (Ascaridiosis) 152 2.5. Benh giun dua a cho 155 4 3. CAC BENH GIUN KIM 158 3.1. Benh giun kim ga (Heterakiosis) 15 8 3.2. Benh giun kim a ngua (Oxyuriosis) 161 4. BENH GIUN LUON (Strongyloidosis) 164 4.1. Can benh, ky chu va vi tri ky sinh 164 4.2. Hinh thai can benh 164 4.3. Vong doi 165 4.4. Dich te hoc 166 4.5. Co che sinh benh 167 4.6. Trieu chung lam sang 167 4.7. Benh tich 167 4.8. Chan doan 167 4.9. Bieutri 168 4.10. Phong benh 168 5. BENH GIUN XOAN 6 GIA SUC M 0T MONG 168 5.1. Benh do Strongylus equynus 169 5.2. Benh do Alfortia edentatus 171 5.3. Benh do Delafondia vulgaris 172 5.4. Benh do Trichonema 174 5.5. Chan doan cac benh giun xoan o gia sue mot mong 175 5.6. Bieu trj cac benh giun xoan o gia sue mot mong 175 5.7. Phong benh giun xoan cho gia sue mot mong 176 6 . CAC BENH GIUN XOAN Cl GIA SUC NHAI LAI 176 6 .1. Benh giun xoan do Haemonchus va Mecistocirrus 176 6.2. Mot so benh giun xoan khac o duong tieu hoa gia sue nhai lai 182 7. BENH GIUN KET HAT (Oesophagostomosis) 187 7.1. Can benh, ky chu va vi tri ky sinh 187 7.2. Hinh thai can benh 187 7.3. Vong doi 189 7.4. Bich te hoc 190 7.5. Co che sinh benh 190 7.6. Trieu chung lam sang 190 7.7. Benh tich 191 7.8. Chan doan 191 7.9. B ik tr i 191 7.10. Phong benh 192 8 . CAC BENH GIUN MOC 192 8.1. Benh giun moc 6 loai an thit (Ancylostomosis) 192 8.2. Benh giun moc a loai nhai lai 195 9. BENH GIUN TRON THU0C PHAN B0 TRICHOCEPHALATA 198 9.1. Benh giun toe (Trichocephalosis) 198 5 9.2. Benh giun xoan (Trichinellosis) 202 10. CAC BENH GIUN PHOI 210 10.1. Benh giun phoi Ion (Metastrongylosis) 210 10.2. Benh giun phoi o gia sue nhai lai (Dictyocaulus) 213 11. BENH GIUN THAN LON (Stephanurosis) 216 11.1. Can benh, ky chu va vi tri ky sinh 216 11.2. Hinh thai can benh 216 11.3. Vong doi 217 11.4. Dich te hoc 218 11.5. Co che sinh benh 219 11.6. Trieu chung 219 11.7. Benh tich 220 11.8. Chan doan 220 1 1 .9 . Di8 u tri 220 11.10. Phong benh 220 12. BENH GIUN DA DAY LON 221 12.1. Can benh, ky chu va vi tri ky sinh 221 12.2. Hinh thai can benh 221 12.3. Vong doi 223 12.4. Dich te hoc 224 12.5. Co che sinh benh 225 12.6. Trieu chung lam sang va benh tich 225 12.7. Chan doan 225 12.8. Dieu tri 226 12.9. Phong benh 226 13. BENH GIUN DA DAY GIA CAm 226 13.1. Can benh, ky chu va vj tri ky sinh 226 13.2. Hinh thai can benh 226 13.3. Vong doi 227 13.4. Co che sinh benh 228 13.5. Trieu chung lam sang 228 13.6. Chan doan 228 13.7. Di8 u tri 228 13.8. Phong benh 228 Phan thil ba. O0NG VAT CHAN OOT KY SINH VA BENH DO O0NG VAT CHAN 0 O T GAY RA 234 Chuong 7. DAI ClTONG VE D0NG VAT CHAN DOT KY SINH 234 1. DAC DIEM HINH THAl, CAU TAO VA PHAN LOAI 234 1.1. Dac diem hinh thai, cau tao 234 1.2. Phan loai 235 6 2. DAC DIEM SINH HOC, VAI TRO GAY BENH VA BIEN PHAP PHONG TRlT DONG VAT CHAN DOT 236 2.1. Dac diem sinh hoc 236 2.2. Vai tro gay benh cua dong vat chan dot ky sinh 237 2.3. Bien phap ca ban de phong va diet dong vat chan dot ky sinh 239 Chuorng 8. VE, GHE, CON TRUNG KY SINH VA g A y BENH 243 1.V EV A G H E 243 1.1. Phan bo Ixodoidea 243 1.2. Phan bo mat (Gamasoidea) 248 1.3. Phan bo mo (Trombidiformes) 249 1.4. Phan bo ghe (Sarcoptiformes) 249 2. CON TRUNG KY SINH 254 2.1. Dac diem hinh thai, cau tao cua con trung ky sinh 254 2.2. Cac con trung ky sinh va truyen benh 255 Phan thur tif. DON BAO KY SINH VA BENH DO O dN BAO GAY RA 261 Cltuvng 9. DAI ClTOfNG VE DON BAO KY SINH VA BENH DO DOHV BAO GAY RA 261 1. HINH THAI VA DAC DIEM SINH HOC CUA DON BAO KY SINH 261 1.1. Hinh thai 261 1.2. Dac diem sinh hoc 262 2. PHAN LOAI DON BAO KY SINH 263 2.1. Lop Ciliata (lop mao trung) 263 2.2. Lop Sporozoa (lop bao tu trung) 263 2.3. Lop Flagellata (lop roi trung) 264 2.4. Lop Rhizopoda (lop chan gia) 265 3. DAI CUONG VE BENH DO DON BAO GAy RA 265 3.1. Duong cam nhiem 265 3.2. Tac dong cua don bao tren co the ky chu 265 3.3. Phan ung cua co the ky chu khi bi don bao ky sinh 265 3.4. Chan doan benh do don bao ky sinh 266 3.4. Xet nghiem phan tim cau trung ky sinh (Eimeria spp., Isospora spp...) 266 3.5. Phong, tri benh don bao ky sinh 270 C/titang 10. MOT SO BENH ROI TRUNG Of GIA SUC 271 1. DAC DIEM CUA ROI TRUNG THU0C HO TR YPANOSOMA TIDAE 271 2. MQT SO BENH ROI TRUNG Cl GIA SUC 272 2.1. Benh tien mao trung (Trypanosomosis) 273 2.2. Benh say thai do Trichimonas 6 bo (Trichomonosis) 278 2.3. Benh djch do giao cau a ngua (benh tiem la ngua) 280 7 Chuang 11. MOT SO BENH BAO TIJ* TRUNG 6 GIA SUC 283 1. BENH HUYET BAO TU* TRUNG 283 1.1. Benh le dang trung a bo (Piroplasmosis) 283 1.2. Benh Theileria 6 bo (Theileriosis) 288 1.3. Benh bien trung o bo (Anaplasmosis) 293 1.4. Benh don bao duong mau Leucocytozoon a ga 296 2. BENH CAU TRUNG (COCC1DIOSIS) 301 2.1. Dai cuong ve cau triing ky sinh 301 2.2. Benh cau trung ga (Avian coccidiosis) 303 2.3. Benh cau trung tho (Rabbit coccidiosis) 310 2.4. Benh cau trung Ion (Swine coccidiosis) 314 2.5. Benh cau trung be, nghe (Bovine coccidiosis) 317 3. BENH BAO TlT TRUNG 6 THIT (SARCOCYSTOSIS) 321 3.1. Can benh, ky chu, vi tri ky sinh 321 3.2. Dac diem hinh thai can benh 322 3.3. Vong doi 322 3.4. Dich te hoc 323 3.5. Trieu chung lam sang 323 3.6. Benh tich 324 3.7. Chan doan 324 3.8. Dieutri 324 3.9. Phong benh 325 8 LOfI NOI DAU Ky sinh trung thu y la mon hoc cung cap nhung kien thuc ve ky sinh trung hoc va > r r > r benh do ky sinh trung gay ra a gia sue, gia cam. Nhung kien thuc nay rat can thiet cho sinh vien nganh Thu y va nganh Chan nuoi thu y cua cac truong Dai hoc Nong nghiep, > F \ dong thai rat can cho can bo thuy dang lam viec a cac co quan thu y va dia phuomg. Hien nay, nhu cau ve tai lieu hoc tap cua sinh vien a tru&ng dai hoc noi chung va truong Dai hoc Nong Lam noi rieng ngay cang tro nen cap thiet. Phuong phap giang day moi - phuong phap giang day lay nguoi hoc lam trung tam - chi co the thuc hien co hieu qua khi Nha truong dap ung dii nhu cau ve tai lieu hoc tap cho sinh vien. Giao trinh Ky sinh trung th u y cua tac gia Nguyen Thi Kim Lan va cs bien soan do r r > Nha xuat ban Nong nghiep xuat ban nam 1999 da dap ung duoc nhu cau hoc tap cho sinh vien tu nam 1999 den nay. Song, sau 12 nam su dung, cuon giao trinh nay hien nay khong con phu hop o muc do tot doi voi hoat dong day va hoc cua Thay va Trd nua. De gop phan nang cao chat luong dao tao trong giai doan moi - giai doan chuyen tu dao tao theo hoc che nien che sang dao tao theo hoc che tin chi, chung toi da bien soan cuon giao trinh Ky sinh trung va benh ky sinh trung thu y. Noi dung cua cuon giao trinh phong phu, cap nhap duoc nhicng kien thirc moi, cac ket qua nghien cuu ve ky sinh trung hoc thu y, vua la tai lieu hoc tap, vica la tai lieu de sinh vien, dong nghiep va ban doc tham khao. Mac du tac gia da rat co gang, dong thoi nhan duoc su gop y cua cac dong nghiep o truong Dai hoc Nong nghiep Ha Noi, truong Dai hoc Y - Duoc va truong Dai hoc r ■> \ r Nong Lam - Dai hoc Thai Nguyen, song cuon giao trinh co the con nhieu thieu sot. Tac gia mong nhan duoc y kien dong gop cua cac em sinh vien, dong nghiep va ban doc de cuon giao trinh duoc hoan thien hon trong nhung lan tai ban sau. Xin tran trong cam on! Tac gia PGS. TS. Nguyen Thi Kim Lan 9 MC* DAU 1. DINH NGHIA VA N 0I DUNG MON HOC 1.1. Djnh nghia hien tirong ky sinh Hien tugng ky sinh la mot trong nhung hinh thuc sinh ton cua sinh vat, dac diem cua hinh thuc ton tai do la: Mot co the song nay song tren hoac trong mot ca the song khac, su dung co the song ay de co lgi cho minh. Thuat ngu "hien tuomg ky sinh” lan dau tien dugc viet bang tieng Hy Lap: “Parasitos ” (Para co nghTa la: Cung nhau, sitos co nghia la dinh duong), thuat ngu nay dung de chi nhung sinh vat song nhd vao sinh vat khac. Leukart la nguoi dau tien dua ra khai niem “vat ky sinh”: “vat ky sinh la tat ca nhung sinh vat nao tim thuc an va cho a tren sinh vat khac Ve ban chat cua hien tugng ky sinh, trong mot thai ky kha dai, nguoi ta chi de cap dugc den tinh chat phuc tap cua hien tugng nay, ma khong dua ra dugc mot dinh nghia ro rang: Hien tugng ky sinh la gi? Ngay nay, hien tugng ky sinh dugc Erehov V. R. dinh nghTa nhu sau: “Hien tuomg ky sinh la moi quan he phuc tap giita hai sinh vat, trong do, mot sinh vat (ky sinh trung) 7 7 r 7 7 tarn thai hay thuang xuyen cu tru trong ca the sinh vat kia (ky chu) de lay dich the, to chuc cua ky chu lam thuc an, dong thai lam cho ky chu bi ton hai den mot muc do nao do ve mat sinh vat hoc Trong djnh nghia nay, Erehov V. R. da neu ro moi quan he qua lai, doi khang giua hai sinh vat (ky sinh trung va ky chu), moi quan he ve khong gian (cu tru thuang xuyen hay tam thoi), quan he ve dinh duong (ky sinh trung lay djch the, to chuc cua ky chu), ve tac hai cua ky sinh trung. Day la djnh nghTa co ban, hieu dugc dinh nghTa nay la co so de phan biet hien tugng ky sinh voi cac hien tugng khac nhu: Hien tugng cong sinh, hien tugng hoai sinh. 1.2. Dinh nghia va noi dung cua ky sinh trung hoc, ky sinh trung thu y hoc * Ky sinh trung hoc la gi? Ky sinh trung hoc la khoa hoc nghien cuu ve moi quan he giua vat ky sinh va vat chu (ky sinh trung va ky chu), nit ra cac quy luat co ban trong qua trinh thich nghi cua co the vat ky sinh va vat chu, tao co so de de xuat cac bien phap dau tranh voi cac benh ky sinh trung, nham nang cao sue khoe con nguoi va phat trien vat nuoi, cay tr6 ng (dan theo Nguyen Thi Le va cs, 1996; Nguyen Thi Kim Lan va cs, 2008). Noi dung cua ky sinh trung hoc gom: Ky sinh trung hoc dong vat va ky sinh trung hoc thuc vat. - Ky sinh trung hoc thuc vat (Phytoparasite): La khoa hoc nghien cuu ky sinh trung a thuc vat va cac benh do chung gay ra a thuc vat. 11 - Ky sinh trung hoc dong vat (Zooparasite): La khoa hoc nghien cuu ky sinh trung a dong vat va cac benh do chung gay ra a dong vat. Ky sinh trung hoc dong vat bao gom: Ky sinh trung y hoc va ky sinh trung thu y hoc. * Ky sinh trung thuy hoc La mon khoa hoc chuyen nghien cuu ve ky sinh trung co nguon goc dong vat, ky sinh o gia sue, gia cam va cac vat nuoi khac, nghien cuu ve benh do chung gay nen va bien phap phong tri. Pham vi nghien cuu cua ky sinh trung thu y gom: Nghien cuu ve vi tri cua ky sinh trung trong he thong phan loai dong vat hoc, nghien cuu ve dac diem sinh hoc (hinh thai, cau tao, chu ky phat trien), nghien cuu ve su phan bo dia ly cua ky sinh trung. Pham vi nghien cuu cua benh ky sinh trung gom: Nghien cuu ve dac diem djch te cua benh, co che sinh benh, benh ly va lam sang cua benh, ve bien phap chan doan va phong tri benh co hieu qua cao. 2. MOI QUAN HE GlCTA MON KY SINH TRUNG THU Y VCfl CAC MON HOC k h Ac Ky sinh trung thu y la mon hoc chuyen mon cua nganh dao tao Bac sy thu y va Ky su chan nuoi thu y. Xet trong moi quan he tien quyet va logic, mon ky sinh trung thu y co quan he mat thiet voi nhieu mon hoc, trong do co nhung mon sau: 2.1. Mon Dong vat hoc: La mon hoc co so cua ky sinh trung hoc thu y. Mon ky sinh trung thu y phai dua tren nhung kien thuc cua mon Dong vat hoc de nghien cuu ve hinh thai, cau tao, ve phan loai, ve chu ky phat trien cua cac ky sinh trung. Ngugc lai, mon Ky sinh trung thu y lam sang ro horn, cu the va phong phu han nhung kien thuc ma sinh vien duoc hoc a mon Dong vat hoc. 2.2. Mon Giai phau, Sinh ly benh va Giai phau benh dong vat: DS xac dinh vi tri ky sinh cua cac loai ky sinh trung, xac dinh benh tich va tim ky sinh trung ky sinh, mon Ky sinh trung thu y can nhung kien thuc ve giai phau, Sinh ly benh va Giai phau benh dong vat. Mon Ky sinh trung thu y phai dua vao nhung kien thuc cua cac mon hoc nay de mo kham, de nghien cuu co che sinh benh va nhung bien d6 i dai thS, vi th£ do ky sinh trung gay ra a gia sue, gia cam. 2.3. Mon Dich te hoc: Benh ky sinh trung co noi dung nghien cuu ve dich te hoc (luu hanh benh hoc). Vi vay, nhung kien thuc ve dich te hoc rat cSn thiSt, la ca sa d£ nghien cuu nhung yeu to lien quan den su phat sinh, phat trien benh ky sinh trung, tir do co bien phap phong tru co hieu qua. 2.4. Mon Mien dich hoc: Ky sinh trung ky sinh kich thich ca thS vat chu va a ca the vat chu thuang xuat hien kha nang mien dich. Nhung kiln thuc ve mien dich giup hieu sau sac horn ve mien dich chong ky sinh trung. dong thai mien dich chong ky sinh trung lai lam ro han nhung kien thuc chung ve mien dich hoc. 2.5. Mon chan doan benh: De co bien phap didu tri va phong benh hieu qua, cin phai chan doan dung benh. Cac kien thuc cua mon ch&n doan benh giup sinh vien biet phuong phap chan doan lam sang, phi lam sang, d6 ng thai biet tien luang benh tren vat nuoi. 12 2.6. Mon Diro’c ly hoc thu y: Benh ky sinh trung can dung cac loai hoa dugc de phong tri, vi vay nhung kien thuc cua mon Dugc ly la ca sa cho viec su dung thuoc dung, an toan va hieu qua. 3. GlOfI THIEU N 0I DUNG GlAO TRINH KY SINH TRUNG THU Y Giao trinh Ky sinh trung thu y dung cho bac dao tao dai hoc gom bon phan: - Phan thu nhat. Dai cuang ve ky sinh trung va benh ky sinh trung thu y; - Phan thu hai. Giun san ky sinh va benh giun san a gia sue, gia cam; - Phan thu ba. Dong vat chan dot ky sinh va benh do dong vat chan dot; - Phan thu tu. Dan bao ky sinh va benh do dan bao gay ra. 3.1. Phan thu nhat. Dai cuong ve ky sinh trung va benh ky sinh trung thu y Phan nay gom 2 chuang: Chuffng 1. Dai cuffng ve ky sinh trung thuy Noi dung chuang 1 trinh bay ve ky sinh trung va ky chu; dac diem dai song ky sinh cua ky sinh trung; anh huong qua lai giua ky sinh trung va ky chu. Chuffng 2. Dai cuffng ve benh ky sinh trung thuy Noi dung chuang 2 trinh bay ve: Khai niem benh ky sinh trung thu y, quy djnh cach goi ten benh ky sinh trung; mien djch trong benh ky sinh trung; tac hai cua benh ky sinh trung doi vai sue khoe dong vat va nang suat chan nuoi; dong thai trinh bay ve bien phap phong tri benh ky sinh trung; dich te hoc benh ky sinh trung va hoc thuyet diet tru benh giun san cua Skrjabin. 3.2. Phan thir hai. Giun san ky sinh va benh giun san o’ gia sue, gia cam Phan nay gom 4 chuang: Chuffng 3. Dai cu ffng ve giun san va benh giun san & gia sue, gia cam Noi dung chuang 3 trinh bay ve: Khai niem va phan loai giun san, khai niem va phan loai benh giun san, cac phuong phap chan doan benh giun san a gia sue va gia cam. r Chuffng 4. San la va mot so benh san la Noi dung chuang 4 trinh bay: Dac diem hinh thai, cau tao va vong dai cua san la; mot so benh san la thuang gap a gia sue, gia cam nhu: Benh san la gan a sue vat nhai lai, benh san la ruot lgn, benh san la da co, benh san la tuyen tuy, benh san la a ca quan sinh san gia cam, benh san la ruot gia cam. Day la nhung benh san la pho biln va gay tac hai lan doi vai gia sue va gia cam a Viet Nam. Chuffng 5. San day va mot so benh san day Noi dung chuang 5 trinh bay: Dac diem hinh thai, cau tao, vong dai, phan loai san day va mot so benh san day thuang gap a gia sue, gia cam. Cac benh dugc trinh bay gom: Benh san day Moniezia 6 gia sue nhai lai, benh san day a ga, benh san day a cho va meo, benh gao lgn, benh gao bo, benh lu san c6 nho, 13 bfnh au san nhieu dau, benh ken nuac. Day la nhung benh do san day truong thanh hoac do au trung san day gay ra, thuang gap nhieu a vat nuoi. Chuffng 6. Giun tron va mot so benh giun tron Noi dung chuang 6 trinh bay: Dai cuong ve giun tron ky sinh; cac benh giun dua (nhu: Benh giun dua lgn, benh giun dua be, nghe, benh giun dua ngua, benh giun dua ga, benh giun dua cho); cac benh giun kim (benh giun kim ga, benh giun kim ngua); benh giun luan, cac benh giun xoan 6 gia sue mot mong (mot so benh giun xoan nhu: Benh do Strongylus equynus, benh do Alfortia edentatus, benh do Delafondia vulgaris, benh do Trichonema); benh giun xoan a gia sue nhai lai (benh giun xoan do Haemonchus va Mecistocirrus); benh giun ket hat; benh giun toe; benh giun tron thuoc phan bo Trichocephalata (benh giun toe, benh giun xoan); cac benh giun phoi (benh giun phoi lgn, benh giun phoi a gia sue nhai lai); benh giun than lgn; benh giun da day lgn, benh giun da day gia cam. 3.3. Phan thir ba. Dong vat chan dot ky sinh Gom 2 chuang: Chuffng 7. Dai cuffng ve dong vat chan dot ky sinh Noi dung chuang 7 trinh bay: Dac diem hinh thai, cau tao va phan loai dong vat chan dot; dac diem sinh hgc, vai tro gay benh, bien phap phong tru dong vat chan dot ky sinh. Chuffng 8. Ve, ghe va con trung ky sinh Noi dung chuang 8 trinh bay: Phan loai ve, ghe va con trung ky sinh; benh ghe ngam do loai Sarcoptes scabiei gay ra a nhieu loai gia sue va gia cam. 3.4. Phan thu- tir. Don bao ky sinh va benh do don bao gay ra Gom 3 chuang: Chuffng 9. Dai cuffng ve dffn bao ky sinh va benh do dffn bao gay ra Noi dung chuang 9 trinh bay: Dac diem hinh thai, cdu tao cua dan bao; phan loai don bao ky sinh; dai cuong ve benh do don bao gay ra o gia sue va gia cdm. r Chuffng 10. Mot so benh trung roi ff gia sue Noi dung chuang 10 trinh bay: Dac dilm cua trung roi Trypanosomidae; mot s6 benh trung roi o gia sue (benh tien mao trung, benh say thai do Trichomonas a bo, benh dich giao cau o ngua - benh tiem la ngua). Chuffng 11. Mot so benh bao tic trung ff gia sue Noi dung chuong 11 trinh bay: Cac benh huygt bao tu trung (g6 m: Benh le dang trung o bo, benh Theileria a bo, benh bien trung a bo); cac benh cdu trung (giai thieu dai cuong v£ cdu trung ky sinh, benh cAu trung ga, benh cau trnng tho, benh cau trung lgn). 14 Phan thu> nhat DAI ClidNG VE KY SINH TRUNG VA BENH KY SINH TRUNG THU Y • a Chuang 1 DAI CUONG VE KY SINH TRUNG THU Y 1. KY SINH TRUNG VA KY CHU Ky sinh trung va ky chu la hai doi tugng co moi quan he qua lai doi khang. Hieu ve ky sinh trung va ky chu cua no la co so cho nhung nghien cuu ve benh ky sinh trung va bien phap phong tri, nham bao ve sue khoe va nang cao sue san xuat cua vat nuoi. 1.1. Khai niem va phan loai ky sinh trung 1.1.1. Khai niem ky sinh trung Ky sinh trung la nhung sinh vat song nhd vao sinh vat khac dang song, chiem doat cac chat dinh duong cua sinh vat do de song va phat trien. Vi du: Giun dua lgn (Ascaris suum), san la gan (F. hepatica), tien mao trung (Trypanosoma evansi)... la cac ky sinh trung. Trong hien tugng ky sinh, con vat ky sinh (ky sinh trung) nho be va yeu hon rat nhieu so voi con vat ma no ky sinh. Vat ky sinh can vat chu phai song de chiem doat dinh duong lien tuc hoac nhieu lan, dong thoi vat chu la noi cu tru thudng xuyen hoac tam thoi cua vat ky sinh. 1.1.2. Phan loai ky sinh trung Ky sinh trung co nhieu cho cu tru va nhieu cach song khac nhau. Vi vay, co the phan loai ky sinh trung theo mot so can cu sau: * Theo nguon goc: Chia thanh 2 loai: - Ky sinh trung dong vat. - Ky sinh trung thuc vat. * Theo cho cu tru cua ky sinh trung: Chia thanh 2 loai: - Ngoai ky sinh trung (Epizoa): La nhung ky sinh trung ky sinh 6 mat ngoai co thi. Vi du: Ve, ghe, ran... - Noi ky sinh trung (Entozoa): La nhung ky sinh trung ky sinh a trong co thi. Vi du: Cac ky sinh trung o duong tieu hoa, duong ho hap... 15 * Theo cach song cua ky sinh trung: Chia thanh 3 loai: - Ky sinh trung bat buoc (Obligatus): La nhung ky sinh trung bat buoc phai song ky sinh vao mot ca the khac, chung khong the song duoc neu roi khoi ky chu. Vi du: Giun, san, ghe, ran... - Ky sinh trung tuy nghi (Facultas): La nhung ky sinh trung co the song tu do d ngoai canh, chi ky sinh d vat chu khi doi. Vi du: Cac con trung hut mau co canh. - Ky sinh trung ngau nhien (Facultas): Loai nay thudng song tu do, nhung cung co the song nhd mot ky chu neu bat ngd xam tap ky chu do. Vi du: Dia, vat... Neu ky sinh trung ngau nhien vao mot ky chu khac ky chu binh thudng cua no thi goi la ky sinh trung lac chu. * Theo dai song ky sinh: Chia thanh 2 loai: - Ky sinh trung vinh vien (Obligatus): La nhung ky sinh trung ca ddi d ky chu, khong luc nao rdi ky chu. Skrjabin K. I. va Schutz R. S. (1940) da chia cac ky sinh trung nay thanh hai nhom co ban theo dac diem quan he voi moi truong ben ngoai. + Ky sinh trung co dinh: Tat ca cac giai doan phat trien cua ky sinh trung deu hoan thanh trong co the ky chu (vi du: Giun tron Trichinella spiralis khong bao gid gap no d ngoai co the va chi truyen true tiep khi co con vat khac an thit con vat mang ky sinh trung). + Ky sinh trung dinh ky: Mot so giai doan phat trien nhat dinh phai hoan thanh d moi truong ben ngoai (vi du: Giun dua, san la...). - Ky sinh trung tam thoi: Nhung ky sinh trung nay phat triln tu trung din giai doan truong thanh deu d ngoai canh, chung xam nhap vao ky chu c6 t la d l \iy thuc an, sau khi an, no lai rdi ky chu va chi tim den ky chu khi doi (vi du: Muoi, dia...). r * Theo ban chat cua ky sinh trung: Chia thanh 2 loai: - Ky sinh trung chuyen loai: La nhung ky sinh trung chi co thi ky sinh d mot loai vat hay mot vai loai gan giong nhau ve phuong dien dong vat hoc. Vi du: Giun tron Parascaris equorum chi ky sinh d ngua, lira, la. - Ky sinh trung phiem loai: La nhung ky sinh trung co thi ky sinh d nhilu loai vat rat khac nhau (vi du: Ve, ghe, tien mao trung...). 1.2. Khai niem va phan loai ky chu (vat chu) 1.2.1. Khai niem ky chu Ky chu la nhung sinh vat dang s6 ng bi ky sinh trung s6 ng nhd tam thdi hay lau dai va bi chiem doat chat dinh dudng. 16 Vi du: Lgn la ky chu cua giun dua lgn (.Ascaris suum); trau, bo la ky chu cua san la gan (Fasciola spp.). Ky chu la moi truong ngoai canh quan trgng nhat cua ky sinh trung. Nhung yeu to tu nhien chi tac dong dugc vao ky sinh trung thong qua ky chu. 1.2.2. Phan loai ky chu Can cu vao dac tinh phat due va thich ung cua ky sinh trung doi voi doi song ky sinh ma co the phan ky chu thanh nhung loai sau: - Ky chu cudi cung La nhung sinh vat de ky sinh trung song nho va phat due den luc thanh thuc ve giai tinh, co kha nang sinh san dugc. Vi du: Trau, bo la ky chu cuoi cung cua san la gan (Fasciola spp.). - Ky chu trung gian Ky chu trung gian la nhung sinh vat de ky sinh trung song nho va phat due trong giai doan au trung. Vi du: Lgn la ky chu trung gian cua san day Taenia solium; Oc Limnaea la ky chu trung gian cua san la gan (.Fasciola spp.). - Ky chu trung gian bo sung (ky chu trung gian 2) Trong qua trinh phat due, au trung da qua giai doan 6 ky chu trung gian thu nhat > ■> t nhung van can mot ky chu trung gian thu hai de hoan thanh su phat due cua au trung. Ky chu trung gian thu hai nay goi la ky chu trung gian bo sung. Vi du: San day Diphyllobothrium latum co cac ky chu sau: + Ky chu cuoi cung: Nguoi, cho, meo. + Ky chu trung gian: Bg nuoc. + Ky chu trung gian bo sung: Ca. - Ky chu chuyen tinh Ky chu chuyen tinh la ky chu dugc ky sinh trung chgn lgc chat che de ky sinh. Vi du: Nguoi la ky chu chuyen tinh cua san day Taeniarhynchus saginatus', be, nghe la ky chu chuyen tinh cua giun dua Neoascaris vitulorum. - Ky chu du’trii’ Au trung cua ky sinh trung truoc khi vao co the ky chu cuoi cung lai vao mot sinh vat khac va khong tiep tuc phat trien dugc nua. Sinh vat khac nay dugc goi la ky chu du tru. Ky chu cuoi cung nuot ky chu du tru se bi nhiem ky sinh trung. Vi du: Giun Syngamus trachea ky sinh 6 khi quan ga. NSu trung co sue gay benh cua giun nay bi dong vat chan dot hoac giun d^t nu6 t thi 4u trung no ra, qua duong tieu hoa vao to chuc co cua ky chu du trir va khong tiep tuc phat trien dugc nua. Neu ga nuot ky chu du tru se bi benh. 17 - Ky chu dufrng cung Au trung cua ky sinh trung co the vao co the sinh vat khong phai la vat chu thich hop cua no de phat due thoi ky dau, nhung sau mot thoi gian thi bi chet vi khong thich nghi duoc voi sinh vat nay. Sinh vat nay goi la ky chu duong cung. Vi du: Giun tron Strongyloidea ky sinh d duong tieu hoa ngua, au trung giun chui vao da nguoi thi sau mot thoi gian ngan se bi chet vi khong thich nghi duoc. 2. DAC DIEM DC*I SONG KY SINH CUA KY SINH TRUNG Ky sinh trung la nhung sinh vat nen co nhung dac diem chung cua sinh vat, dong thoi cung co nhijng dac diem rieng cua ky sinh trung. De ton tai va phat trien, ky sinh trung phai co nhung dac diem song thich nghi voi phuong thuc song ky sinh cua chung. Cac dac diem cua doi song ky sinh trinh bay dudi day the hien ro net su thich nghi cua ky sinh trung. 2.1. Dac diem ve hinh thai va kich thirdc 2.1.1. Dac diem hinh thai Hinh thai cua ky sinh trung rat da dang. Tuy tung loai ma ky sinh trung co hinh thai rieng. Nhung ky sinh trung don bao thi hinh the nhu mot te bao nhung khong thuan nhat: Co loai hinh dang tuong doi tron nhu cau trung, co loai hinh thoi nhu trung roi duong mau, giun tron co hinh ong, san la co hinh la, con trung co chan va canh... Ky sinh trung co nhung giai doan phat trien khac nhau. O cac giai doan phat trien khac nhau, ky sinh trung co hinh thai khac nhau. Su khac nhau ve hinh thai d cac giai doan phat trien co the den muc kho nhan dinh. Vi du: Ruoi, muoi truong thanh co chan va canh, nhung khi la au trung (doi ru6 i, bp gay muoi) thi khong co chan va canh. 2.1.2. Dac diem ve kiclt thir&c Ky sinh trung co kich thudc rat khac nhau, co loai co kich thudc rdt nho (vi du: Piroplasma spp. truong thanh co kich thuoc 2-4x2 jam), trong khi co nhung loai co kich thuoc rat Ion (san day Moniezia spp. dai toi 4 - 5 m). Co nhung loai ky sinh trung trong qua trinh s6 ng co su thay doi r k nhilu v l kich thuoc (vi du: San la, san day, giun tron khi truong thanh co kich thuoc 1cm nhung khi la au trung thi rat nho, phai dung kinh hien vi mod quan sat duoc). Co loai ky sinh trung trong mot thoi gian rdt ngSn cua ddi s6 ng ky sinh cung co thi thay doi ldn v l kich thuoc (vi du: Ve sau khi hut no mau, kich thuoc co thi co thi gdp 50 lan so voi luc doi). Dac diem kich thuoc cua ky sinh trung khac vi khuin d cho: V l kich thuoc. vi khuan tuong ddi thuan nhat (deu phai dung kinh hiln vi mod quan sat duoc), con ky sinh trung thi tuy loai, tuy tung giai doan ma co thi thAy duoc bang mat thudng hoac kinh hien vi. 18 2.2. Dac diem ve cau tao co the cua ky sinh trung 2.2.1. Dac diem thoai hoa khi quan khong can thiet La nhung sinh vat song ky sinh, ky sinh trung co cAu tao co the thich hop cho doi song cua chung. Do doi song ky sinh, nhijng khi quan cua co the khong can thiet da bi thoai hoa hoac mat di hoan toan. Vi du: San la co ong tieu hoa rat don gian; san day khong co ong tieu hoa; giun san khong co co quan van dong, khong co thi giac, thinh giac, khiru giac, khong co he tuan hoan va ho hap. Nhin chung, nhung khi quan khong can thiet cho ddi song ky sinh deu chiu nhung bien doi thoai hoa hoac bi loai tru hoan toan. Noi ky sinh trung co nhung bien doi ro net va sau sac hon nhieu so vdi ngoai ky sinh trung. Ky sinh trung tam thoi bj bien doi it, ky sinh trung vinh vien bi bien doi nhieu hon. 2.2.2. Dac diem tien hoa, tao ra nhicng khi quan m&i can thiet Cung do ddi song ky sinh, do nhu cau ton tai ma qua nhieu the he, ky sinh trung da tao ra va hoan chinh nhung khi quan dac biet, giup cho ddi song an bam cua chung duoc thuan lpi. Nhung khi quan nay giup ky sinh trung de dang tim den ky chu, bam vao ky chu, chiem dinh duong cua ky chu, sinh san de dang tren ky chu hoac d ngoai canh. Trudc kia nguoi ta cho rang, ky sinh trung tim duoc ky chu la nhd hudng tinh dac biet. Tren co so thuyet hudng tinh, ngudi ta da phan biet cac loai hudng tinh khac nhau: Hoa hudng tinh, ly hudng tinh, nhiet hudng tinh, dien hudng tinh, quang hudng tinh. Vdi nhung nghien cuu sau hon, Skrjabin K. I. va Frosmann (1963) cho biet, ky sinh trung va nhung sinh vat ha dang co nhung khi quan rieng goi la phan tich quan. Chinh phan tich quan da giup ky sinh trung tim duoc ky chu can thiet va tao cho ky sinh trung co kieu song rieng thich hop tren ky chu. Vi du: Co au trung ky sinh trung chui sau vao dat (trudc kia goi la dia hudng tinh) hoac di chuyen xa nhung chat doc hai doi vdi chung (trudc kia goi la hoa hudng tinh am) thi cung chi la do ky sinh trung nhd vao phan tich quan ma da co cam giac dac biet, dan tdi nhung phan xa thich hop. Cung nhd co phan tich quan ma ky sinh trung due va cai co the de dang tim gap nhau de giao phoi. Hien nay, nhd co nhung nghien cuu ve phan tich quan cua ky sinh trung ma ngudi ta co the xua duoi ky sinh trung bang cach danh lac hudng va lam m§t tac dung cua phan tich quan. Vi du: Dung cac loai tinh dau co mui thorn dac biet de xua du6 i muoi tranh xa ngudi. Sau khi da tim duoc ky chu, ky sinh trung can bam chac vao ky chu d£ l&y thuc an, vi vay cac khi quan bam (cac giac bam, moc bam) (con goi la cac co quan c6 dinh) phat trien manh. 19 Giac bam la nhung cho lorn hinh hoi tron hoac bau due, hoac hinh ban nguyet, dugc r \ r cau tao bang he thong co vong va co toa. Khi nhung thd co nay co lai, giac bam cua ky r * sinh trung mut vao hom cua mot nu thit (mo that day), nhd vay ky sinh trung bam chac dugc vao ky chu. Vi du: San la Fasciola spp. co 2 giac bam, san day Moniezia spp. co 4 giac bam. Moc bam phat trien d nhieu loai ky sinh trung (vi du: San day Taenia solium co 2 hang moc gom 22 - 44 moc). Moc dugc cau tao bang chat kitin hoac sung, phan bo d > * t * * tren mom hoac dinh dau. Moc la khi quan dac biet de co the dam va cam sau vao to chuc cua ky sinh trung nhu mot ludi cau vi moc thudng cong ve phia sau. Vi du: Chan muoi nhd co nhirng mong bam nen co the bam chac vao ky chu de hut mau, mac du ky chu co gang di dong va co rut co de xua duoi chung. Giun san d trong ruot ky chu tuy thudng xuyen bi nhu dong ruot de doa tong ra ngoai, nhung nhd co nhung khi quan dac biet nen van co the bam chac vao vj tri ky sinh. Khi da bam dugc vao ky chu, do ky sinh trung can chiem doat dinh duong cua ky chu nen cac khi quan dac biet dugc hoan thien. Vi du: Voi muoi co cau tao rat tinh vi de co the thoc vao da ky chu (mac du da nhieu loai ky chu rat day va cung). Muoi con tiet ra chat chong dong mau de tranh mau dong lai lam tac voi hut. Giun moc cung co tuyen tiet chat chong dong mau (thuoc nhom heparin) lam cho mau khong dong va hut dugc de dang. De duy tri noi giong trong dieu kien con ngudi luon tim each chong lai chung, ky sinh trung da tao ra va hoan thien cac khi quan giup cho viec sinh san dugc de dang trong nhung hoan canh kho khan. Vi du: Muoi phai giao phoi trong khi bay, nen muoi due ngoai bo phan duong vat con co cang bam de giu chac muoi cai. Muoi cai vi s6 lAn gap muoi due rat it nen no co tui chua va duong tinh dl thu tinh cho nhirng lua trung tiep theo. 2.3. Dac diem sinh san cua ky sinh trung Ky sinh trung co nhung dac diem sinh san sau: - Sinh san vo tinh: La hinh thuc sinh san don gian nhat. Vi du: Cac ky sinh trung dudng mau sinh san theo hinh thuc nay (tien mao trung, le dang trung...). - Sinh san hieu tinh: D6 i vdi nhung ky sinh trung ludng tinh (san la, san day): Co thi tu giao ph6 i giua bo phan sinh due due va bo phan sinh due cai tren cung mot ca thi, hoac co thi giao phoi cheo giua hai ca the. Tuy nhien, khi co tu 2 ca thi trd len, ky sinh trung ludng tinh thudng giao phoi cheo giua ca the nay vdi ca the khac. D6 i vdi nhung ky sinh trung don tinh (nhilu loai giun tron, dong vat chan dot): Sinh san theo hinh thuc con due va con cai giao phoi vdi nhau. 20 Tuy loai ky sinh trung ma bang hinh thuc sinh san huu tinh se de ra trung (vi du: Giun dua), hoac de ra au trung (vi du: Giun bao), co khi rat kho nhan dinh la trung hay au trung (vi du: Giun chi de ra trung, trong co au trung, khi au trung cu dong, do vo trung rat mong nen vo trung gian ra theo hinh the au trung). - Phoi tu sinh: Day la hinh thuc sinh san dac biet cua ky sinh trung. Co nhung loai ky sinh trung chi sinh san d giai doan truong thanh, nhung co nhung loai ky sinh trung con co kha nang sinh san 6 giai doan au trung. Do la hinh thuc phoi tu sinh. Vi du: Au trung san la co dang boc, ben trong boc sinh ra nhieu te bao phoi. Tir mot au trung san la o giai doan tien au trung co the sinh san ra nhieu au trung (khi song trong ky chu trung gian). Do hinh thuc sinh san phong phu ma ky sinh trung sinh san nhanh, nhieu va de dang. Vi du: Mot con san day Taenia saginata co the de 150 trieu trung mot nam, giun dua Ion de 200.000 trung moi ngay (Cram, 1925). 2.4. Dac diem song cua ky sinh trung 2.4.1. Dac diem moi truong song Moi truong song cua ky sinh trung la co the vat chu ma no ky sinh va ngoai canh ma no chju tac dong gian tiep thong qua vat chu. Ngoai canh cung la moi truong tac dong true tiep den ky sinh trung khi no o giai doan la trung hoac au trung. D6 song va phat trien, ky sinh trung can co moi truong song thich hop ve nhiet do, do Am, dAt dai, do cao cach mat bien... Muc do thich hop co the co gian, co nhung bien do nhat dinh. * Cac loai moi tru&ng song cua ky sinh trung Co the phan ra 2 loai moi truong song cua ky sinh trung: - Moi tru&ng song toi thuan: La moi truong ma o do ky sinh trung co nhung dieu kien thuan loi nhat, tot nhat de song va phat trien. - Moi tru&ng song toi thieu: La moi truong ma o do ky sinh trung co nhung dieu kien thAp nliAt de duy tri su song, neu dieu kien song thap hon thi ky sinh trung khong the song noi. Vi du: Au trung Miracidium cua san la Fasciola spp. song 6 moi truong tu nhien co nhiet do thich hop nhat la 22 - 23°C, nhiet do de no ton tai bien dong tu 15°C den 30°C. Neu nhiet do thap hon 15°C hoac cao hon 30°C thi au trung nay khong the song duoc. Au trung nay doi hoi pH cua nuoc ma no dang song la 5-7,7; pH thich hop nhat cho Au trung phat trien la 6 - 7. Neu pH thap hon 5 va cao hon 7,7 thi au trung bi chet. * Anh huong cua moi tru&ng ngoai canh den ky sinh triing va benh ky sinh trung Moi truong tu nhien bao gom nhieu yeu to: Khi hau, thoi tiet (nhiet do, do Am, anh sang), dAt dai, song ho, do cao cach mat bien. Moi truong tu nhien khong thi khong co nhirng biln dong: Thoi tiet luon thay doi, cac chat luon chuyen hoa. Ngoai nhung thay 21 doi tu nhien con co nhirng thay doi do con nguoi tac dong (vi du: Con nguoi phat quang cay co, khoi thong cong ranh...). Nhirng thay doi nay tac dong ro ret den ky sinh trung va tao nen su biln dong cua ky sinh trung theo moi truong. Cung vi vay ma co su bien ddng cua ky sinh trung theo miia. Vi du: Cl Viet Nam, ruoi, muoi phat trien chu yeu tir thang 4 den thang 9 la nhung thang nong am thich hop voi ruoi muoi; bo chet lai phat trien chu yeu tir thang 1 0 den thang 4 la nhirng thang mat, lanh va kho rao, thich hop voi bo chet. Dieu kien khi hau, nhat la nhiet do va do am co anh huong den khu he ky sinh trung. Su thay doi nhiet do va do am cua moi truong lam cho khu he ky sinh trung thay doi. Dieu nay de hieu bdi ky sinh trung va ky chu trung gian cua chung yeu cau dieu kien nhiet do va do am nhat dinh de song va phat trien. Neu moi truong khong co nhirng thay doi dang ke thi su bien dong cua ky sinh trung khong ro ret. Noi chung, yeu to moi truong ngoai canh khong nhirng co the quyet dinh su co mat cua mot ky sinh trung nao do ma con quyet dinh muc do, kha nang hoat dong va phat tan cua ky sinh trung. Vi du: San la trong nhieu giai doan song (khi la trung, au trung) can phai co moi truong nude de song. Vi vay, nhirng viing hoan toan kho can thi khong co san la va benh san la. Nhung viing it nude co it benh, nhirng viing nude nhieu thi benh san la phat trien. ? f r * Anh hu&ng cua moi tru&ng true tiep (ky chu) den ky sinh trung Moi co quan, moi noi trong co the dong vat deu co ky sinh trung ky sinh. Giun san thudng tap trung song ky sinh 6 duong tieu hoa, ky sinh trung don bao thudng s6 ng trong mau hoac trong duong tieu hoa cua dong vat. Moi loai ky sinh trung co mot noi ky sinh thich hop, nhung cung co nhirng loai ky sinh d nhieu noi khac nhau (vi du: Au trung san day Echinococcus). Ve moi truong ky chu, trong cung loai ky chu thi con non nhiem ky sinh trung thudng nhieu hon con truong thanh. Nhirng con vat 6 m ylu, suy dinh duong nhiem nang hon nhirng con du dinh duong va khoe manh. Trong cac co quan cua vat chu, co quan tieu hoa (ruot, da day, gan), mau, da la nhung noi ky sinh trung thudng ky sinh nhieu hon. Co quan sinh due thudng it co ky sinh trung ky sinh hon. * Tinh thich nghi cua ky sinh trung v&i moi tru&ng sdng Ylu to moi truong tuy co tac dong ldn din toan bo su song, su hoat dong cua ky sinh trung, nhung cung can phai xet den su thich nghi cua ky sinh trung d6 i vdi moi trudng. La nhung sinh vat, qua nhieu the he noi tilp nhau, ky sinh trung dAn din hinh thanh su thich nghi vdi moi trudng song khong hoan toan thich hop. Sir thich nghi nay dua vao dac tinh bien di va di truyen cua sinh vat, co thi tao thanh nhirng kilu s6 ng mdi cho ky sinh trung. 22 Vi du: Muoi song hoang dai tro thanh ban thuan duong roi vao han nha d voi con ngudi va tro thanh thuan duong. Neu bi con ngudi xua duoi thi muoi lai ra ngoai song ban thuan duong hoac hoang dai... tao thanh mot vong thich nghi luan quan (thay rat ro d cac viing diet muoi chong benh sot ret). Nhin chung, ky sinh triing co the thich nghi vdi hoan canh moi trudng. Neu sir thich nghi do duoc tien hanh qua nhieu the he thi co the tro thanh ban chat sinh thai cua ky sinh triing. Nhung yeu to phu thuoc cua ky sinh triing doi vdi moi trudng can quan niem la nhung yeu to tac dong den hien tuong song. Yeu to nay luon thay doi chu khong phai la bat di bat dich. Do do, viec cai tao moi trudng la het sue can thiet de khong che ky sinh triing. Nhung mat khac, vi qua trinh khong che la mot qua trinh keo dai song song vdi qua trinh cai tao moi trudng, nen cung phai tinh den ky sinh triing co the thich nghi va tir do can co nhirng doi pho kip thoi vdi su thich nghi moi cua ky sinh triing. Noi cach khac, su doi pho vdi ky sinh triing bang bien phap cai tao moi trudng phai thudng xuyen, kip thoi va lau dai de pha vo tinh thich nghi cua ky sinh triing vdi moi trudng song. Yeu to moi trudng tuy la yeu to quyet dinh, nhung khong phai la duy nhat, vi dac diem song cua ky sinh triing con phu thuoc vao chu ky cua ban than no, phu thuoc vao yeu to ky chu. 2.4.2. Yeu to chu ky phat trien (vong dai) cua ky sinh trung * Chu ky phat trien cua ky sinh triing la gi? Toan bo qua trinh phat trien, thay doi qua nhung giai doan khac nhau cua ddi song •t \ > r > ky sinh triing, ke tir khi la mam sinh vat dau tien, cho den khi lai san sinh ra mam sinh vat moi, tao ra mot the he moi dupe goi la chu ky. Vi du: Chu ky phat trien cua ruoi: Ruoi --------► Trung -------► Doi -------------Nhong «---------- Quan niem ve chu ky khong phai la khong gian doan, hinh dung nhu la mot dudng tron khong co diem md dau va khong co diem ket thuc. Do quan niem nay nen mdi co danh tir chu ky (chu nghTa la vong tron) hoac vong dai. Khi noi den chu ky cua mot ky sinh triing nao do, ta co the mo ta tir giai doan nao cung duoc. Nhung do thoi quen theo mot trinh tu nhat dinh ma ngudi ta thudng mo ta chu ky bat dau tir mam sinh vat dAu tien (ky sinh triing trudng thanh). * Cac kieu chu ky Chu ky cua ky sinh triing hoac thuc hien tren co the ky chu, hoac thuc hien d moi trudng tu nhien. Neu lay moi trudng ky chu lam trung tam thi moi trudng tu nhien thudng duoc goi la ngoai canh hoac ngoai gidi. 23 Chu ky phat trien cua ky sinh trung gom nhung kieu sau: - Co nhung ky sinh trung ma chu ky cua chung hoan toan thuc hien d ngoai canh, khong can toi ky chu. Do la chu ky cua nhung ngoai ky sinh trung nhu ruoi, muoi (tuy co luc song ky sinh vao ky chu, nhung khong can song bam vao ky chu moi thuc hien dupe chu ky toan ven). - Mot so ky sinh trung khac co chu ky thuc hien luc 6 ngoai canh, luc d ky chu. Vi du: Chu ky cua cac san la. - Mot so ky sinh trung co chu ky thuc hien hoan toan tren ky chu ma khong can den ngoai canh moi thuc hien dupe chu ky. Vi du: Chu ky cua giun bao, cua cac huyet bao tu trung. Nhu vay, co ky sinh trung co kieu chu ky don gian, co ky sinh trung co kieu chu ky phuc tap. Tinh don gian hoac phuc tap cua chu ky anh hudng toi muc do phat trien ky sinh trung va lien quan den muc do pho bien cua benh do ky sinh trung do gay ra. Nhung ky sinh trung co chu ky phuc tap thudng kho ton tai va phat trien, vi chu ky co nhieu khau, va chi can mot khau khong thuc hien dupe hoac bi pha vo la chu ky khong thuc hien dupe. Nhirng ky sinh triing co chu ky don gian se de thuc hien dupe chu ky toan ven, chung khong nhirng de ton tai ma cung de phat trien va nhiem vao ky chu de gay benh. Vi ky sinh triing co nhieu kieu chu ky nen bien phap pha vo chu ky cua ky sinh triing cung co nhieu hinh thuc khac nhau: Hoac cat dirt khau ky sinh triing tir ky chu ra ngoai canh, hoac tir ngoai canh vao ky chu, hoac diet ky sinh triing d ky chu bang cach dung hoa dupe dieu tri. Chu ky co nhirng quy luat nhat dinh, cac giai doan phai tuan tu ke tiep nhau, nhung vi con phu thuoc vao yeu to moi trudng nen thoi gian hoan thanh mot chu ky khong thi co dinh dupe. CJ dieu kien thuan lpi, toe do hoan thanh chu ky se nhanh hon so vdi d moi trudng khong thuan lpi. Vi du: Ve Boophilus can 1-1,5 thang vao miia nong, am de hoan thanh chu ky, con vao miia lanh thi phai tren 3 thang. 2.4.3. Yeu to ky chu Ky chu la yeu t6 khong the tach rdi ky sinh triing. Co 3 kilu quan he giua ky sinh triing va ky chu: - Ky sinh triing chi d ky chii va do tiep xuc ma sang mot ky chu khac. Vi du: Ghe, ran chi song ky sinh tren ky chu, ky chu khac nhiem ghe, ran do tilp xuc vdi con vat bi benh. - Ky sinh triing sdng d ky chu cu6 i ciing, thai mdm benh ra ngoai canh, nhung sau do phai qua giai doan d mot hoac hai ky chu trung gian roi mdi trd lai ky chu cu6 i ciing. Vi du: San la gan, giun phoi lpn. 24 - Ky sinh trung a ky chu va tu ky chu dugc dua vao vat moi gioi truyen benh, sau do vat moi gioi nay lai truyen ky sinh trung vao mot ky chu khac. Vi du: Ky sinh trung duong mau, giun chi. Nhu vay, ky sinh trung gay benh khong the thieu duoc yeu to ky chu (gom co ky chu cuoi cung, ky chu trung gian). Tu su quan he khang khit cua ky sinh trung voi ky chu, co the rut ra nhung nhan xet sau: f r + Neu thieu ky chu thi ky sinh trung khong hoan thanh duoc chu ky phat trien. + Neu khong co ky chu thich hop thi ky sinh trung chet hoac co truong hop co the song duoc mot thoi gian ngan va gay mot so tac hai, sau do chet. Vi du: Au trung cua san day Diphyllobothrium mansoni ky sinh 6 nhai. Neu ran an nhai se bi benh san day truong thanh. Nhung khi ngudi la ky chu khong thich hop an t # r r r r ? thit ech nhai co au trung chua duoc nau chin hoac dap tint ech nhai vao mat (chua dau mat theo tap quan sai lam cu) thi au trung se khong thanh san day truong thanh ma van r r r r tiep tuc song duoi dang au trung, tao nen nhirng u san 6 da day hoac 6 mat cua nguoi (trong u san co au trung san day). Khi ky sinh trung song trong ky chu khong thich hop co the gay nen nhung truong hop benh dac biet, thuong goi la nhung benh do ky sinh trung lac chu. + Ky sinh trung sau khi vao ky chu phai tim den vi tri ky sinh thich hop de ky sinh. Moi ky sinh trung co vi tri ky sinh nhat djnh trong co the. Nhung truong hop ky sinh trung ky sinh o cac vi tri khac duoc goi la ky sinh trung lac cho (hoac ky sinh trung di cu). Hien tuong di cu xay ra do nhieu yeu to khac nhau. Nhung yeu to chu yeu la do ky sinh trung thay doi sinh thai, hoac do co the ky chu co nhung thay doi ly hoa tai cho ky sinh trung ky sinh. Su di cu cua ky sinh trung co the gay ra nhirng trieu chung rat bat thuong. Vi du: Truong hop giun chui ong mat gay nen trieu chung dau bung du doi 6 nguoi va gia sue. + Truoc khi ky sinh triing ky sinh co dinh tai mot vi tri, co nhieu loai ky sinh triing co hien tuong di qua mot so noi trong co the. Vi du: Giun dua Ion, giun luon, giun phoi... Su chu dong di quan cac co quan, cac mo de den duoc noi cu tru lau dai, duoc Skrjabin K. I. va Petrov A. M. (1963) goi la su di chuyen (migration). . Duong di chuyen ma trong do giun san di qua he thong noi tang vao gan, qua tinh mach chu va tim vao vong tieu tuan hoan, phoi roi ve ruot, Skijabin K. I. va Petrov A. M. (1963) goi la vong di chuyen gan - phoi - ruot. • Duong di chuyen ma trong do giun san di tir ruot qua he bach huylt, tuyln bach huyet, roi qua tinh mach chu, qua tim vao vong tieu tuan hoan ph6 i va lai vao duong tieu hoa, Skrjabin K. I. va Petrov A. M. (1963) goi la vong di chuyin limplto - phoi - ruot. • Mot trong so nhirng kieu di chuyen thudng gap la giun san dimg lai o ph6 i, s6 ng trong nhu mo hay trong duong ho hap (khi quan, phe quan), duoc goi la vong di chuyen I imp ho - phoi. 25 • Sir di chuyen theo duong limpho - phoi nhung dung lai 6 tim hay dong mach chu goi la vong di chuyen limpho - tim. • Doi khi giun san khong nhung di chuyen qua vong tieu tuan hoan, ma con qua ca vong dai tuAn hoan. Su di chuyen qua tilu va dai tuan hoan duoc goi la di chuyen dai tuan hoan, can cu vao giai doan d£u chung qua duong limpho hay qua gan ma duoc goi la vong di chuyen gan - dai tuan hoan, hay limpho - dai tuan hoan. • Su di chuyen tu do trong co the ky chu duoc goi la vong di chuyen noi tang - toan than. + Duong xam nhap cua ky sinh trung vao co the ky chu thay doi tuy loai ky sinh trung. Da so giun san xam nhap qua duong tieu hoa. Mot so xam nhap qua da (giun chi, san mang, giun luon...). Mot so ky sinh trung co the co nhieu duong xam nhap. Vi du: Au trung giun luon, giun moc co the xam nhap qua da hoac qua ducmg tieu hoa cua ky chu. + Ky sinh trung co mot hoac nhieu ky chu thich hop. Vi du: Muoi, ghe, tien mao trung co the ky sinh o nhieu loai ky chu khac nhau. Nhirng ky sinh triing co the lay dinh duong o nhieu loai ky chu khac nhau dugc goi la nhirng ky sinh triing tap thuc. Tinh “tap thuc” cua mot so ky sinh triing lam cho benh ky sinh triing co thi truyen tir sue vat sang nguoi hoac ngugc lai tir nguoi sang sue vat. Vi du: Giun bao (Trichinella spiralis) ky sinh 6 lgn co the truyen sang nguoi do nguoi an thjt lgn song co au triing giun nay. 3. An h HirdNG q u a l a i g ilTa k y s in h t r u n g v A k y c h u Tir khai niem “hien tuomg ky sinh”, chung ta thay quan he giua ky sinh triing va ky chu la moi quan he rat phuc tap giua hai sinh vat song. Tinh phuc tap the hien 6 nhirng tac dong co hai cua ky sinh triing gay ra cho ky chu, dong thoi ky chu cung co nhirng phan ung tro lai, nham ngan chan tac dong cua ky sinh triing. 3.1. Tac dong cua ky sinh trung den ky chu Tac dong nay phu thuoc vao so lugng va doc lire cua ky sinh triing, sue ch6 ng do cua co the ky chu, giai doan phat due cua ky sinh triing. Tac dong cua ky sinh triing doi voi ky chu gom nhieu mat: - Tac dong ca gi&i Hau het cac ky sinh triing deu gay nen nhirng bien loan co gioi, ngan tro it nhilu chuc nang cua cac khi quan ma no xam nhap; hoac lam tic; hoac chen ep va pha hoai cac to chuc; hoac lam thung, lam rach; hoac do cac khi quan bam hut cua ky sinh trimg lam troc niem mac, gay xuat huyet. Thuong thay hau qua cua tac dong nay la gay viem cAp tinh, thu cap tinh, man tinh. Viem dan toi san sinh mot cai vo bang t6 chuc lien kit boc lay ky sinh triing, cai vo va ky sinh triing boc ben trong khi chit di biln thanh mot cai hat, trong hat co hien tugng voi hoa. 26 - Tac dgng chiem doat chat dinh duong Ky sinh trung tir nuoi duong bang an to chuc cua ky tioao chiem doat mot phan thuc an cua ky chu da tieu hoa, hoac hut mau ky chu. Tac dong nay tiep dien lien tuc bdi rat nhieu ky sinh trung, gay nen ton hai rat to Ion cho ky chu (thieu mau, gAy rac...). - Tac dong dau doc Doc to cua ky sinh trung gom tat ca nhung san pham cuoi cung cua qua trinh trao doi chat cua ky sinh trung, noi va ngoai doc to do ky sinh trung tiet ra. Ky sinh trung bai tiet cac chat doc hang ngay, ky chu hap thu chat doc, sinh ra nhung bien loan khac nhau, nhung thudng thay nhat la bien loan than kinh (co giat, bai liet...), va tuan hoan (gay dung huyet, ban huyet). Doc to con lam te liet cac te bao thuc bao cua ky chu. Noi chung, chat doc do au trung sinh ra manh hon chat doc do ky sinh trung truong thanh sinh ra. - Tac dong truyen benh Mot so loai chan dot dot sue vat, lam con vat kho chiu, co the bi viem da, nhung dieu nay khong nguy hiem. Dieu nguy hiem la khi hut mau ky chu, chung truyen nhung benh co the thanh djch luu hanh giet hai nhieu sue vat. Vi du: Muoi truyen benh sot ret va benh sot vang d nguoi, ve truyen benh le dang trung, bo chet truyen benh djch hach, ruoi Glossina truyen benh trung roi, con trung hut mau truyen benh nhiet than... Ngoai ra, giun san bam vao niem mac gay thuong tich cung pha vo phong tuyen thuong bi, mo duong cho cac vi khuan trong moi trudng chung s6 ng (ruot) xam nhap vao co the, vi khuan se gay nen mot benh ghep voi benh ky sinh trung. Ky sinh trung va vi trung thudng ket hop lam ton hai them cho ky chu, tao thanh vong xoan benh ly vdi dien bien phuc tap, lam cho bieu hien lam sang them tram trong. 3.2. Phan ung cua ky chu doi voi ky sinh trung Loai ky chu co the gay anh hudng den su sinh trudng va phat due cua ky sinh trung. Vi du: San day Bothriocephalus latus co the dai hang may met d ngudi, trong khi chi dai 20 - 40 cm d ruot meo, tuy hinh thai khong thay doi. Khi bi ky sinh trung ky sinh, ky chu luon co phan ung de lam giam bdt tac hai do ky sinh trung gay ra cho ban than minh. Noi chung, co the ky chu phan ung lai ky sinh trung bAng ba loai phan ung: Phan ung thuc bao, phan ung te bao va phan ung the dich. - Phan intg thuc bao: Nhung tl bao di dong cua ky chii tan cong ky sinh trung va co thi tieu diet chung bang co nang thuc bao. Neu hieu qua thuc bao khong day du thi r sinh ra nhung phan ung te bao. - Phan intg te bao: Phan ung thudng thay nhat la viem va tang sinh bach cau Eosin. Nhung phan ung khac la: To chuc bien doi, cac te bao nhiem ky sinh trung to len hoac 27 phat trien qua muc, gay thanh nhung ung; hoac te bao bien thanh te bao t6 chuc lien ket, bao lay ky sinh trung, tao thanh nang (ken). - Phan intg the dich: Xuat hien khang the trong mau ky chu, co the gay cho ky chu tinh mien dich, hoac trang thai qua man. Trang thai qua man do co the, mot khi da chua nhung doc to qua man (anaphylatoxiri) do ky sinh trung sinh ra thi tro nen nhay cam hon voi cung ky sinh trung ay, do do co the co phan ung rat manh voi lan cam nhiem thu hai. Vi du: Trang thai qua man d nhung con vat da bi nhiem giun dua. 3.3. Tinh cam thu cua sue vat doi voi benh ky sinh trung Nhung yeu to sau day anh hudng den tinh cam thu doi vdi benh ky sinh trung - Giong (dong, noi): Co nhung giong cam thu it hay nhieu vdi nhung ky sinh trung nhat dinh. Trong mot viing thudng co ky sinh triing ton tai va ky sinh thi ky sinh triing gay tac hai it hon so vdi nhung viing tir trudc chua co, nhirng giong sue vat nhap noi cam thu hon vdi benh da co d dia phuong so vdi cac giong sue vat dia phuong (vi du: Benh le dang triing the hien rat nang d dan bo nhap noi, trong khi the hien nhe hon nhieu d dan bo dia phuong). - Tuoi va tinh bigt: Sue vat non bi ky sinh triing duong ruot nhieu hon sue vat trudng thanh (giun dua, cau triing). Noi chung, sue de khang cua sue vat non kern hon sue vat trudng thanh. Tinh biet hinh nhu khong anh hudng true tiep den ty le va cuong do nhiem ky sinh triing. - Che do dinh dieang va chant soc nuoi duffng: Dinh duong thieu, nhat la thieu vitamin (A, C) va protein, chuong chat choi, kern ve sinh... la dieu kien thuan lori cho su phat sinh benh ky sinh triing. Thoi quen an uong cua sue vat (an phan, an s6 ng) da giup cho su xam nhap cua mot so ky sinh triing vao vat chu. Miia chan tha ngoai d6 ng co dai hay ngan cung anh hudng den cudng do nhiem ky sinh triing. Trai lai, dinh duong day du co the lam cho benh ky sinh triing phat nhe hay khong phat ra, co thi lam cho tuoi tho cua ky sinh triing giam, tham chi ban than ky chu co thi t6 ng ky sinh triing ra ngoai. Quan ly cham soc vat nuoi tot la bien phap lam giam ty le va cudng do nhiem ky sinh triing. - Tinh trang sire khoe Khi sue vat dang mac mot benh nao do hoac mSc benh da khoi nhung sue khoe chua hoi phuc, khi hau thay doi that thudng, lam viec qua sire... co thi thuan loi cho su phat sinh mot so benh ky sinh triing. Nguoc lai, khi con vat khoe manh, kha nang sinh trudng phat due cua ky sinh triing bi han che, s6 luong ky sinh triing trudng thanh it, tham chi tuoi tho cua ky sinh triing bi rut ngan di. 28 Cltutmg 2 DAI Cl/ONG VE BENH KY SINH TRUNG THU Y • • 1. KHAI NIEM VE BENH KY SINH TRUNG THU Y, QUY DINH CACH GOI TEN BENH KY SINH TRUNG 1.1. Khai ni£m Benh ky sinh trung thu y la benh do nhung ky sinh trung dong vat gay ra (giun san, dong vat chan dot, dong vat don bao). Co 3 yeu to chu yeu lam phat sinh benh ky sinh trung: . „ - Phai co dong vat co tinh cam thu doi voi ky sinh trung. Neu dong vatVeo tinh cam thu voi ky sinh trung thi hoac ky sinh trung khong xam nhiem vao duoc, hoac co xam nhiem vao nhung cung khong sinh truong phat due duoc va khong co kha nang gay benh. - Phai co ky sinh trung co sue gay benh. Mam benh ky sinh trung can phat due den giai doan co sue gay benh thi khi xam nhap vao co the vat chu, no moi co the tiep tuc sinh trudng, phat due thanh ky sinh trung trudng thanh va gay benh cho vat chu duoc. - Phai co dieu kien ngoai canh thich hop de ky sinh trung phat due khi con d ngoai canh. Nhung yeu to nay tac dong true tiep den ky sinh trung. Nhung tac dong nay la gian tiep khi ky sinh trung da xam nhap vao vat chu. Trong do, dieu kien nhiet do, am do, khu he dong - thuc vat rat quan trong doi vdi sir phat sinh benh ky sinh trung. Benh ky sinh trung thudng the hien dudi hai the: Cap ti'nh va man tinh, phu thuoc vao so luong ky sinh trung, doc luc cua chung va sue khoe cua vat chu. - The cap tinh: Thudng the hien d nhirng dong vat non, nhirng dong vat om yeu. Trudng hop nay trieu chung lam sang the hien ro d vat chu. Neu khong duoc dieu tri kip thoi thi ty le tu vong cao. - The man ti'nh: Thudng thay d nhung dong vat beo khoe, trudng hop nay trieu chung lam sang bieu hien khong ro, benh dien ra am i, keo dai, it khi chet. 1.2. Quy djnh cach goi ten benh ky sinh triing Theo he thong phan loai, ky sinh triing dong vat duoc phan loai nhu sau: Nganh (Phylum) Lap (Class) Bo (Order) Ho (Family) Giong (Genus) Loai (Species) Chung (Veriety) 29 Ngoai ra, co the co nhirng su phan loai: Bo phu, ho phu, giong phu, sieu ho... Cach goi ten theo he thong phan loai nhu sau: - Ten ho: Lay ten giong lam co so + duoi idea - Ten ho phu: Lay ten giong lam co so + duoi idae - Ten loai ky sinh triing duoc goi bing 2 tir la tinh, tir dau viet hoa chi ten giong, tir sau viet thudng chi ten loai. Vi du: Ascaris suum, Moniezia expansa... - Ten chung: Lay ten giong, loai lam co so + ten chung, co the them hoac khong them chu var d giua. Vi du: Sarcoptes scabiei var equy, hoac Sarcoptes scabiei equy. Ngudi ta thudng them ten tac gia da tim ra giong hay loai do va nien hieu da mo ta giong hay loai do. Vi du: Fasciola hepatica, Linnaeus 1758. Fasciola gigantica, Cobbold 1885. - Ten benh ky sinh triing: Lay ten giong cua ky sinh triing lam co so, thay tiep vT ngu bang os is. Vi du: Fasciolosis (benh do Fasciola gay ra). Ascariosis (benh do Ascaris gay ra). N6 u benh do nhieu loai ky sinh triing trong ciing mot ho gay ra, ten benh ky sinh triing duoc goi nhu sau: Lay ten ho lam co so, thay duoi ae bang osis. Vi du: Trichostrongylidosis (benh do nhieu loai giun xoan thuoc ho Trichostrongylidae gay ra). 2. MIEN DICH TRONG BENH KY SINH TRUNG 2.1. Dac diem chung ve mien djch trong benh ky sinh triing Co the co nhirng trudng hop mien dich sau: - Mien diclt tir nhien: Tinh mien dich nay co the hoan toan hay tuomg d6 i. Vi du: Ngudi khong bao gid nhiem giun dua Ascaridia galli cua ga. - Mien dich thu dicac: Trong cac benh ky sinh triing, mien dich thu duoc khong bao gid tien tdi tieu diet hoan toan ky sinh triing (khac vdi nhieu benh do vi triing). Trong trang thai mien dich ay, nhirng hoat dong phong ngu cua co the ky chii khong cho ky sinh triing phat trien, hinh thanh mot the thang bang giua ky sinh triing va ky chu. Mien dich thu duoc co hai loai: + Mien dich thu diro’c chu dong: Day la mien dich co duoc sau khi tiem vacxin hay mot khang nguyen chet. Tuy nhien, doi vdi nhieu benh ky sinh trung, diSu nay kho thuc 30 hien, trir mot so benh giun tron va don bao. Tuy nhien, co the gay mot trang thai phong nhiem doi voi mot so benh (nhu benh le dang triing, bien triing) bang each cho ve chua so luong ft le dang triing dot be, hoac tiem mau cua nhirng con da khoi benh (chi con chua mot it le dang triing, doc luc kem) va tiem vao nhirng cho it mach mau (duoi), hoac gay benh thuc nghiem roi chua ngay cho con vat khoi ve phuong dien lam sang de tao mien dich thu duoc chu dong. + Mien dich thu duffc bi dong: Mien dich nay co duoc do tiem huyet thanh cua con vat da duoc mien dich. Tuy nhien, dieu nay khong co y nghTa thuc te trong cac benh ky sinh triing. Trong mot so trudng hop, sau khi dung thuoc tri ky sinh triing, sue mien dich con duoc duy tri mot thoi gian nhat dinh. Vi du: Doi vdi san la Fasciola, sue mien dich con duy tri duoc 1,5-2 thang, doi vdi san day Moniezia duoc 1-1,5 thang. Noi chung, sue mien dich duy tri khong qua 2 thang sau khi khoi benh. 2.2. Khang nguyen va khang the Cung nhu khang nguyen cua vi triing, khang nguyen cua ky sinh triing la ban than no hay nhirng san pham ma no bai tiet. Ky chu phan ung lai tac dong kich thich cua ky sinh triing (khang nguyen) bang cach san sinh khang the, do la thanh phan Globulin trong huyet thanh cua ky chu. Do sir phat trien va tac dong cua ky sinh triing thudng la thu cap tinh hay man tinh nen tinh mien dich doi vdi benh ky sinh triing thudng chi la tuong doi. Khang nguyen va khang the co tinh dac hieu: Ky sinh triing loai nao kich thich co the ky chu sinh ra khang the loai ay; ky chu sinh khang the chi nham mot loai ky sinh triing nhat dinh. Tuy nhien, trong benh ky sinh triing lai co hien tuong phan ung mien djch nhom, tuc la khang the chong duoc khang nguyen cua nhung loai ky sinh triing gan nhau. Vi du, tinh phong nhiem cua bo chong Piroplasma bovis cung cho con vat tinh phong nhiem chong Anaplasma marginale. Su san sinh khang the la do hoat dong cua toan than ky chu, dudi sir chi phoi va chi dao cua he thong than kinh, nhung cung tap trung vao may khi quan chinh cua he thong vong mac noi bi (he lam ba, la lach, mot phan phoi, gan). La lach la khi quan san sinh khang the rat manh, do do cat bo la lach hay lam ngan tro chuc nang cua la lach co thi lam giam sue de khang cua co the ky chu doi vdi ky sinh triing, lam cho ky sinh triing san sinh rat manh. benh dang d the tiem an co the phat thanh the lam sang. Huyet thanh mien djch co nhirng dac tinh: Ngung ket, dung giai, tram dien (kit tua), dieu ly, co djnh bo the, qua man va dj cam hoa. Vi du, sau khi giun dua xam nhiem vao ky chu 20 ngay, ky chu tang sinh bach cau Eosin va sinh khang the. Neu luc do ky chu <%> > ^ •? 4.1.2. Cltan doan bang soi kinh hien vi Phuong phap nay nham tim chinh ky sinh triing, khi do chung thudng d giai doan la trung, au triing... do ky sinh triing trudng thanh bai xuat trong phan, nude mui, nude 35 tieu... cua con vat om. Tim thay trong phan co trung cua ky sinh trung tuc la co ky sinh trung trong duong tieu hoa da de trung, hon nua co the cSn cu vao hinh thai trung ma xac dinh loai ky sinh trung. Co ba cach chan doan bang soi ki'nh: - Soi phan: Dung chdn doan cac benh ky sinh trung duong tieu hoa nhu benh giun san, cau trung. - Soi chdt ngoai da: Dung cho cac benh ky sinh trung ngoai da (ghe). - Soi mau: Dung cho cac benh ky sinh trung duong mau. Hoac soi true tiep mot giot mau tuoi, neu ky sinh trung con song va di dong thi thay no ngay, nhat la no lam cho cac huyet cau chuyen dong (vi du: Roi trung Trypanosoma evansi). Hoac soi tieu ban mau sau khi nhuom mau. 4.1.3. Chan doan thi nghiem Chi dung khi hai phuong phap tren khong dung duoc (vi du: Ky sinh trung 6 sau trong noi tang, benh moi d thoi ky dau). De chan doan thi nghiem, co the phai nuoi cay trong moi trudng nhan tao; truyen benh cho dong vat thi nghiem; chan doan mien dich hoc, huyet thanh hoc; chan doan te bao hoc bang cach xac dinh ty le bach cau Eosin; chan doan ky chu (nuoi cay ky sinh trung gay benh tren ky chu trung gian da biet); phan ung noi bi, giai phau tren con vat song... 4.2. Tien luong bfnh ky sinh trung Benh ky sinh trung thu y co tien luong tot hay xau phu thuoc vao ba yeu to: - Ty le vat nuoi chet nhieu hay it. - Kha nang lay lan va truyen cac benh khac. Nhung benh co thi truyln true tilp tir ca the om sang ca the khoe la dang so nhat, vi co the gay thanh dich luu hanh. Trudng hop ky sinh trung co the truyen cho ky chu mot benh ghep them vao benh do no gay ra cung nghiem trong (vi du: Ve truyen benh le dang trung). - S6 luong ky sinh trung. Phan ldn ky sinh trung chi nguy hilm khi no xam nhap vat chu den mot s6 luong nao do. Hon nua, so luong cang nhilu thi cac biln loan benh ly cang nang, hau nhu chi nhung trudng hop cam nhiem them nhilu mdi gay chit sue vat. Hien tuong ky sinh trung phai dat din mot s6 luong nao do mdi co kha nang gay thanh benh dua den ba nhan dinh: - Tuy ky sinh trung thudng co nhilu hon d sue vat non, nhung mot so it ky sinh trung d sue vat trudng thanh cung nguy hilm, vi luc do sue ch6 ng do cua co thi giam thap. Hon nua, sue vat mang ky sinh trung tro thanh mot o tang tru va gieo ric can benh ra ngoai canh, lam cho nhung sue vat khac nhiem m im benh. Nhung con vat mang ky sinh trung rat nguy hien vi chung van khoe manh nen ta khong chu y khi kilm soat dl chira cho chung. Cho nen, can tay ky sinh trung cho tat ca sue vat trudng thanh trong 36 mot dan co benh: Phai \ky cho toan dan, om cung nhu khoe, gia cung nhu non va khong quen nhung con cai co chua. - Ve phuong dien chua benh, hiem co thuoc co hieu luc 100% nen the nao cung de s i ' lai mot so it ky sinh trung. Tuy vay, con vat cung co the duoc coi la khoi benh ve phuong dien lam sang. - Ve phuong dien phong benh, can tranh khong de cho sue vat nhiem ky sinh trung voi so luong nhieu. Muon biet ro cudng do nhiem, co the dem trung bang soi ■> kinh hien vi. 4.3. Chira benh va phong benh ky sinh trung * Chira benh ky sinh triing phai nham dat bayeu cau: - Trudc het phai tieu diet ky sinh trung, dung thuoc tay trung cho con vat (diet ky sinh trung hay tay ky sinh trung con song ra ngoai). Phai dung thuoc hudng ky sinh trung, tuc la doc doi vdi no nhung khong doc hoac it doc doi vdi ky chu. He so giua lieu > r luong doc vdi con vat va lieu luong chira benh cua no phai tren 3. Nen chon thuoc nao co hieu luc nhat doi vdi ky sinh trung, dong thoi it nguy hiem nhat doi vdi ky chu, re tien nhat va de dung nhat (de dang dung cho toan dan). Hudng mdi trong viec chua cac benh ky sinh trung la tim nhung thuoc co hieu luc chong nhieu loai ky sinh trung (vi du: Mebendazole co tac dung tay nhieu loai giun tron). - Phai ngan chan khong cho con vat om tai nhiem: Dua ngay con vat ra khoi noi co benh, tieu doc noi do trudc khi cho sue vat vao lai. - Phai lam cho sue vat om hoi sue: Cho an nhieu, du dinh duong, vitamin va muoi. Co the dung thuoc bo, thuoc kich thich, tiep mau. Givr ve sinh tot, chua cac trieu chung. * Phong benh ky sinh triing: Co nhieu bien phap, nhung deu nham muc dich: Khong cho mam benh ky sinh trung (trung, au trung) phat trien, thuc hien het cac giai doan phat due cua no, de no khong the tro thanh ky sinh trung trudng thanh duoc. Cac phuong phap tan cong ky sinh trung d tung giai doan: 4.3.1. Chong giai doan thir nhat (giai doan ky sinh trung trudng thanh d ky chu cu6 i cung) Co the tieu diet ky sinh trung bang hai phuong phap: Dung thuoc dac hieu diet ky sinh trung (viec diet ky sinh trung nay co tinh chat du phong, tuc la phai thuc hien trudc khi sue vat phat trieu chung benh va trudc khi sue vat gieo rac mam benh ra ngoai canh). Ngudi ta cho rang, co the tieu diet ky sinh trung bang each giet tat ca nhung con vat m&c benh (phuong phap nay triet de nhung ton kem, mac du thit sue vat van sir dung duoc). 4.3.2. Chong giai doan thir hai (giai doan ky sinh triing la trung) Co the dung hai phuong phap: Tieu diet hau het trung bang each thu nhat hit phan cua sue vat om trong chuong va dem chon (bien phap nay phai lam di lam lai nhieu ldn 37 de trung khong co thoi gian phat trien thanh phoi thai), hoac co thi u phan theo phuong phap nhiet sinh hoc. Doi v o i sue vat chan tha, phai co bien phap han che trung tren dong co phat trien thanh trung hoac au trung co sue gay benh. Vi du, cai tao dong co, lam cho dong co kho rao. 4.3.3. Chong giai doan thir ba (giai doan ky sinh trung la trung va 4u trung gay benh d ngoai canh). Co hai cach: - Diet toan bo trung va au trung gay benh ngoai dong co va ao tu bang voi bpt, sunfat sat, sunfat dong v o i luong dung 400 kg cho 1 hecta dong co, 5 kg cho 100 m3 nuoc ao. - Khong cho trung hay au trung co sue gay benh xam nhap vao co the ky chu (cach ly sue vat om, tieu doc dung cu va chuong nuoi, ve sinh thuc an nuoc uong, diet ky chu trung gian). 5. DICH TE HOC BENH KY SINH TRUNG VA HQC THUYET DIET TRIf BENH GIUN SAN 5.1. Djch te h9C benh ky sinh trung Dich te hoc benh ky sinh trung la khoa hoc nghien cuu nhung yeu to lien quan den su phat sinh, phat trien cua benh ky sinh trung, duong truyen ba, phan bo benh ky sinh trung. Nhung yeu to lien quan den dich te hoc cua benh ky sinh trung la: Dieu kien tu nhien, nhung dieu kien can thiet cho su phat due cua ky sinh trung, hoat dong cua con nguoi, dong thai cua ky sinh trung. 5.1.1. Dieu kien tu nhien - Mua vu: O nhung vung co mua vu ro ret, ky sinh trung co su phat trien theo mua. Moi mua co nhiet do va am do khac nhau, nhiet do va am do anh huong Ion din sir phat due cua ky sinh trung. - Dat dai: Tinh chat dat khac nhau cung anh huong tdi sir phat triln cua ky sinh trung, dac biet doi vdi nhung ky sinh trung ma giai doan la trung, au trung phai s6 ng tu do d ngoai canh. - Do cao so vdi mat bien: Cac vung co do cao so vdi mat biln khac nhau thi su phan bo ky sinh trung khac nhau. 6 do cao 2000 met so vdi mat biln, ngudi ta it thdy benh san la gan va mot so loai con trung truyen benh. - Khu he dong vat: Su phat trien cua nhieu loai ky sinh trung cdn co ky chu trung gian, vi vay, sir co mat cac loai dong vat - ky chu trung gian cua chung quylt dinh sir ton tai va phat trien cua chung. Vi du, su ton tai va phat triln cua san la cdn co 6 c nude ngot - ky chu trung gian, su phan bo cua giun bao (Trichinella spiralis) lien quan din ngudi, Ion, loai gam nham va loai an thit. - Khu he thuc vat: Khu he thuc vat lien quan din ngu6 n thuc an cho vat chu cua ky sinh trung, dong thoi tao do che phu va bao ve cho ky sinh trung d ngoai canh. 38 5.1.2. Hoat dgng cua con ngudi Hoat dong cua con ngudi anh hudng ldn den su phan bo cua ky sinh trung. Tap quan chan nuoi do con ngudi tao ra (xay dung chu6 ng trai, thurc an, ve sinh thu y...) co anh hudng ro ret den benh ky sinh trung, co the lam benh ky sinh trung phat ra hoac khong phat ra, phat ra nang hay nhe. Cac hoat dong song cua con ngudi (di lai, chuyen cho gia sue, gia cam...) deu co the mang theo ky sinh trung, lam cho ky sinh trung co dieu kien phat tan va gay benh. Tuy nhien, de co benh ky sinh trung con can co khi hau thich hop, co ky chu trung gian can thiet thi ky sinh trung mdi tiep tuc phat due duoc d noi mdi den. Tap quan sinh hoat cua con ngudi co the lam phat sinh va phat trien mot so benh ky sinh trung. Vi du, d vung con ngudi co thoi quen an thit song, thit tai thi Ion, trau, bo va ngudi co nguy co bi benh gao, benh giun bao nhieu hon nhung vung khong co thoi quen do; hoac do ngudi khong co noi dai tien hop ve sinh thi 1cm d viing do hay bi mac benh gao... 5.1.3. Dieu kien can thiet cho su phat due cua ky sinh trung Phai co ky chu trung gian thich hop thi ky sinh triing mdi phat due duoc. Ky chii trung gian anh hudng nhieu den toe do phat due ciia ky sinh triing va doc lire cua chung: Ky chu trung gian thich hop thi ky sinh triing phat due nhanh hon, ky chu trung gian khong thich hop thi phat due cham lai. Trong thien nhien thudng ton tai song song ky sinh triing va ke thii cua chung. Neu gap ke thu, ky sinh triing thudng bi tieu diet (vi du: Cac loai chim an ve, kien an trung ve; nam ky sinh vao au triing giun moc lam chet au triing...). Ky sinh triing can co co hoi thich hop de xam nhap vao vat chu. Vi du: Au triing F. buski phai theo rau lap, beo, rong... vao duong tieu hoa lorn; au triing san day Cys. tenuicollis phai duoc cho nuot vao duong tieu hoa mdi phat trien thanh san day trudng thanh T. hydatigena... 5.1.4. Dong thai cua ky sinh triing Co nhieu ky sinh triing phat trien theo miia trong nam, vi vay ty le va cudng do nhiem cung bien dong theo miia. Bien dong nhiem ky sinh triing con thay doi theo phuong thuc chan nuoi, tap quan cham soc nuoi duong, tuoi vat chu va dieu kien ve sinh thu y. Bau tieu khi hau dac biet cua mot vung ciing anh hudng den sir phan bo cua ky sinh triing. Tir nhirng van de tren, co the thay rang, dich te hoe cua benh ky sinh triing khac vdi benh truyen nhiem. Benh truyen nhiem do vi triing gay ra, do vi triing sinh san nhanh, lay lan manh nen benh thudng d the cap tinh. Nguoc lai, thdi gian phat due cua ky sinh triing dai, kha nang lay nhiem cham, benh thudng d the man tinh. 39 Benh ky sinh trung muon phat sinh va luu hanh, theo Pavlovsky E. N., can co 8 dieu kien sau: 1. Co ky sinh trung gay benh. 2. Co ky chu man cam voi ky sinh trung. 3. Co con vat mang ky sinh trung trong mot khu vuc nhat dinh. 4. Co ky chu trung gian. 5. Cac ylu t6 ngoai canh (dat, nuoc, nhiet do, Am do) khong can tro su cam nhiem cua ky chu va su phat sinh benh ky sinh trung; khong ngan can su xam nhap cua ky chu trung gian vao con vat man cam; khong ngan can su cam nhiem cua ky sinh trung vao ky chu trung gian va su phat due cua ky sinh trung trong ky chu trung gian. 6 . Co co hoi cho ky chu cuoi cung tiep xuc voi ky chu trung gian. 7. Co dong vat tich tru ky sinh trung (vi du: Chuot tich tru giun bao Trichinella). 8 . Co dieu kien xa hoi phu hop. Nhu vay, yeu cau de co benh ky sinh trung phuc tap hon so voi benh truyen nhiem va cac benh khong truyen nhiem khac. Chinh vi vay ma benh ky sinh trung co the ngan x > / / r f ngua duoc bang cach chi can loai bo mot vai yeu to trong nhung yeu to tren la benh ky sinh trung khong phat ra duoc. 5.2. Hoc thuyet diet trir b£nh giun san r 5.2.1. Casff ly luan va noi dung cua hoc thuyet Skrjabin K. I. (1944) da de ra hoc thuyet tieu diet tan goc benh giun san. Hoc thuyet nay cung co the ap dung cho cac benh ky sinh triing khac. Noi dung chu yeu cua hoc thuyet la du phong co tinh chat chu dong: Dung tit ca cac bien phap co gioi, vat ly (anh sang, nhiet do), hoa hoe (thuoc), sinh vat hoc (sinh vat no diet sinh vat kia) nham tieu diet ky sinh triing tren co the ky chu (dung thu6 c), tieu diet ky sinh triing 6 ngoai gioi, tieu diet ky sinh triing o tdt ca cac giai doan phat due (trung, au triing, ky sinh triing truong thanh), tieu diet ky sinh triing 6 ca ngudi va gia sue. Noi rieng ve mat dieu tri gia sue benh, noi dung cua no cung la du phong, bcri le: Chua cho mot sue vat khoi benh, diet duoc ky sinh triing trong co the no la trir duoc mot con vat mang ky sinh triing, trir duoc mot ngu6n gieo rAc benh. N hu vay, d6i vcri con vat mac benh, la dieu tri, nhung doi voi nhung con vat khac la tich cuc d! phong. Vi vay, viec dung thuoc tay giun san phai dat duoc hai yeu cAu: Chua cho con vat 6m khoi benh va dam bao cho ngoai canh khong bi nhiem mAm benh giun san, tranh mAm benh nhiem vao nhung con vat khac. Neu khong thi dung thu6c tAy giun san va trung ra ngoai chang khac gi giup cho giun san phan tan rong rai 6 ngoai canh. Phai cho thu6c tAy giun san tir luc no chua truong thanh, chua de trung va phai tieu doe that t6t phan co trung giun san va than giun san thai ra. 40 Trong mpt nong trudng, mot trai chan nuoi can ap dung cac bien phap cu the sau day: - Dung thuoc dac hieu de tay giun san. - Dinh ky cho thuoc tay giun san. - Dieu tri tren quy mo ldn. Trong trai, du chi co 10 - 20% so sue vat phat benh thi cung phai dung thuoc tay cho ca dan. Neu khong, nhung con tuy be ngoai khong phat benh nhung cung co the mang ky sinh trung va gieo rac benh. - Tieu diet benh dung ke hoach. Can cu vao lich su phat due cua ky sinh trung, tinh nghiem trong cua benh ky sinh trung ma co ke hoach mot nam tien hanh may lan cho phu hop. - Xir ly phan de diet mam benh giun san. - Thuc hien day du cac phuong phap tren. Muon thuc hien tot ke hoach tieu diet nguyen nhan benh, phai nghien cuu toan dien ve cac van de: Hinh thai, sinh thai, phan bo dia ly, dieu tra khu he, tim hieu lich su phat due cua ky sinh trung, dich te hoc cua benh ky sinh trung, cac phuong phap dieu tri va phong benh. 5.2.2. Nguyen tac chung trong phdng tri nguyen nhan benh giun san Phuong phap thuc te phong tri nguyen nhan benh giun san la ung dung hoc thuyet Skrjabin, ve co ban gom: - Diet giun san d dong vat, muc dich lam cho sue vat khoe manh va ngan ngua ngoai canh khong bi o nhiem mam benh giun san. - Diet giun san d ngoai canh, muc dich la de phong de dong vat khong bi nhiem benh, tuc la diet trung, au trung giun san d phan, diet trung va au trung giun san tu dong sinh hoc d trai chan nuoi, bai chan tha, ve sinh noi uong nude. * Diet giun san dr dong vat. Bao gom nhung viec chinh sau: - Chan doan chinh xac benh de dung thuoc dac hieu dieu tri benh, co hieu qua cao, tranh nguy hiem cho vat nuoi. - Quy mo diet giun san: Xac djnh noi nao can diet giun san d dong vat, noi nao chua can. Phai can cu vao tinh hinh thuc te. Nguyen tac chung la d noi nao phai thi hanh cac phuong phap phong ngua chung thi du so gia sue cam nhiem giun san it cung phai diet giun san tren quy mo rong. - Ky han diet giun san: Phai can cu vao chu ky phat due cua giun san va dieu kien, mua vu chan tha hay nuoi nhot. Nen diet giun san trudc khi chung trudng thanh, vira tranh tac hai ldn cho ky chu, vira tranh cho ngoai canh khong bi o nhiem. Ngay gid cho thuoc cung phai chu y. Vi du: Khi tay giun dua ga, thudng giun duoc bai xu&t ra trong 8 gid dau sau khi cho thuoc, do do cho thuoc vao buoi chieu la thich hop, vi sang horn sau co the thu nhat phan va giun de tieu diet, tranh cho ga khong an lai giun. 41 - Ton trong quy tic phong benh chung. Nhung con vat dugc diet giun san phai duoc nuoi trong chuong khong nhiem trung. Phai tieu doc phan bai xu£t ra bang phuong phap u nong sinh hoc. - Du doan hieu suat diet giun san. Xac dinh so gia sue, gia cam da duoc tay hoan toan hoac s6 giun san duoc bai ra so v o i so luong co trudc khi dieu tri (udc luong) de co ke hoach cho cac buoc diet giun san tiep theo. * Diet trii ng va au trung giun san a phan bang phuotng phap u nong sinh hoc Hang nam, so luong phan chuong san xuat rat Ion va la loai phan bon tot cho cay trong. Phan Ion cac mam benh giun san deu theo phan ra ngoai (trung, au trung, dot san day). Khi xu ly phan phai lam the nao de tieu diet duoc mam benh, phong benh cho ngudi va vat nuoi, dong thoi khong lam giam chat luong phan doi vdi san xuat nong nghiep. Muon giai quyet yeu cau do, ngudi ta thudng dung cac chat hoa hoc, cac nhan to vat ly, cac tac nhan sinh vat hoc. Mam benh giun san co sue chong do rat manh vdi cac chat hoa hoc. Vi du: Trung giun dua ngua co the phat due binh thudng trong dung dich Mercurocrom, sunfat dong, > f y r con iot, cac axit loang. Vi vay, kho diet trung va au trung giun san bang thuoc hoa hoc. Tuy anh sang mat trdi chieu true tiep co the diet duoc trung giun san, nhung anh sang kho tac dong vi trung thudng duoc boc mot ldp phan ben ngoai hoac duoc co xanh che phu. Lam kho chi khien trung ngimg phat due chu khong bi diet (nhat la trung co phoi thai hoac au trung da den thoi ky cam nhiem). Nhiet do thap cung khong co tac dung. Nhan to vat ly co tac dung manh nhat doi vdi mam benh giun san la nhiet do cao tren 45°C, anh hudng ldn den trung va au trung, den 65°C chi can 1 phut la diet duoc trung va au trung. Tir do, ngudi ta loi dung hoat dong cua vi sinh vat de tieu doc phan tu nhien, goi la phuong phap ii nong sinh hoc. Co so khoa hoc cua phuong phap nay la: Dua vao hoat dong cua he vi sinh vat yem khi va hieu khi, phan giai va len men cac chat huu co, lam tang nhiet do cua dong phan u len rat nhieu. 0 nhiet do ay, toan bo mSm benh giun san deu bi tieu diet. Co the ii theo cac cong thuc sau: - Cong thuc 1: Phan chuong : 800 - 1000 kg. La xanh bam nho : 200 kg. Tro bep : 60 kg. Tron tro b£p va la xanh. Cu mot ldp phan rai mot ldp tro bSp tron la xanh. Danh d6 ng. Mat ngoai dung bun, dat udt trat kin. Sau 14 ngay nhiet do d6 ng phan tang den 45 - 5 1°C. - Cong thuc 2: Phan chuong: 800 - 1000 kg. Voi bot : 30 - 50 kg. La xanh : 200 kg. 42 La xanh bam nho tron phan. Cu mot lop la + phan lai rai mot lop voi bot. Danh dong. Ben ngoai dung bun, dat udt trat kin. Sau 11 ngay nhiet do tang den 50 - 51°C; cao nhat la 65°C. - Lam ho u phan: Ho sau 1,5 m, dai va rong 1,5 - 2 m. Duoi ho de 3 - 5 cm co kho hoac cat. Do phan chuong cao 1,25 m. Tren be mat phu mot ldp rac day 10 cm. Tren cung phu mot ldp dat bun day 20 cm. Thoi gian u la 1 - 2 thang. * Diet trung va du trung tu- dong sinh hoc a hai chan Co the tieu diet duoc trung va au trung d bai chan tha gia sue neu ap dung each chan dat luan phien. Vi du: Giun phoi Dictyocaulus filaria d de cuu. Sau khi au trung bai ra ngoai canh phai phat due 6 ngay mdi den thoi ky cam nhiem. Vi vay, phai chia khoang chan dat luan phien 6 ngay mot dot. Dong thdi, au trung cua giun nay song ngoai bai chan dai nhat la mot nam; cho nen sau 1 nam co the cho chan tro lai khoanh thu nhat. Nhung luc khong chan de cuu co the chan Ion, ngua vi chung khong cam nhiem loai giun tron nay. Mot vi du nua la san la gan Fasciola hepatica. Au trung phat due trong co the ky chu trung gian (oc) 30 - 80 ngay tuy dieu kien nhiet do. Gia thiet la ngay ngay thu nhat chan tha, phan trau, bo da co trung san la gan. 6 ngoai thien nhien, 15 ngay sau trung mdi thanh au trung, au trung phai phat due trong co the oc ngan nhat la 30 ngay mdi tro thanh au trung cam nhiem vao trau, bo duoc. Nhu vay, tu trung den khi thanh au trung cam nhiem va phai mat 45 ngay. Do do, co the chan luan phien dong co moi dot khong qua 44 ngay. r * Giu ve sinh no’i uong nuoc Khong cho vat nuoi uong nude ao, ho tu ham. Nhung cong ranh gan noi uong nude phai duoc bao vay, giu kho rao va sach se. Co the cho sue vat uong nude song, suoi, ho luu thong, dudi day co cat soi; hoac nude mua sach. Khong duoc de phan, bun, xac chit tren bd song. Khong lam ho phan, chon xac chet d bd song. Duong vao noi uong nude khong duoc lay loi, phai rao kin. Neu dung nude gieng thi dia diem dao gieng phai xa noi chon sue vat, nghTa dia, nha chua phan, ho phan, chuong sue vat. Gan gieng nen co san cho sue vat den uong nude de dang, san khong duoc lay loi. Mang nude phai giu sach, sau moi lan sue vat uong phai rua sach va de kho. Nhung cho nude u dong gan noi uong nude nen lap bang, nhung bai chan am udt can tieu nude, lam kho. 43 TAI LIEU THAM KHAO (Phhn thir nhat) (Chuang 1: DAI ClTONG VE KY SINH TRUNG THU Y, Chuang 2: DAI Cl/ONG VE BENH KY SINH TRUNG THU Y) Tieng Viet 1. Nguyen Thi Le (1998), Ky sinh trung hoc dai cuong, NXB Khoa hpc v& Ky thuat, Ha Npi, tr. 8 - 74. 2. Skrjabin K. I. va Petrov A. M (1977), Nguyen ly mon giun tron th u y (Bui Lap, Do&n Thj Bang Tam va Ta Thi Vjnh djch tu nguyen ban tieng Nga), Tap I, NXB Khoa hpc Vci Ky thuat, H& Npi, tr. 19 - 38. 3. Trjnh V&n Thjnh (1963), Ky sinh trung thuy, NXB Nong thon, Ha Npi, tr. 60 - 64. 4. Trinh Van Thjnh, Pham Xuan Du, Pham VSn Khue, Phan Djch Lan, Bui Lap, Duong Cong Thuan (1978), Cong trinh nghien ciru ky sinh trung o Viet Nam, Tap II, N X B Khoa hpc v& Ky thuat, H& Npi, tr. 39 - 40, 65 - 70, 73 - 74. 5. Phan The Vi?t, Nguyen Thj Ky, Nguyen Thj Le (1977), Giun san ky sinh a dong vat Vi?t Nam, NXB Khoa hoc v i Ky thuat, tr. 357 - 358. 6. N guyln Thi Kim Lan (2000), "B$nh giun san duong tieu hoa cua de dja phuong d mQt so tinh mien nui phia Bac Viet Nam va bien phap phdng tr i”, Luan an tien sy N ong nghiep, H i Npi. Tieng ntro'c ngoai 7. Bowman D. D. (1999), Parasitoloy fo r veterinarians, W. B. Saunder company, pp. 260 - 285. 8. Johannes Kaufmann (1996), Parasitic infections o f dosm etic animal, Birkhauser Verlag, Berlin, pp. 303 - 304. 9. Jogen Hansen and Brian Perry (1994), The Epidemilogy, D iagnosis and C ontrol o f Helminth Parasites o f Ruminants. A Handbook, pp. 73 - 79. 10. Sousby E. J. L. (1982), Helminths, Arthropods and protozoa o f D om esticated Animal, Lea and Febiger. Philadelphia, pp. 158 - 162. 11. Urquhart G. M., Armour J., Duncan J. L., Dunn A. M., Jennings F. W. (1996), Veterinary Parasitology, Blackwell Scienc, pp. 5 - 20. 44 Phan thu5 hai GIUN SAN KY SINH VA BENH GIUN SAN Cl GIA SUC, GIA CAM Chuang 3 DAI Cl/ONG VE GIUN SAN VA BENH GIUN • • SAn of GIA SUC, GIA CAM 1. KHAI NIEM VA PHAN LOAI GIUN SAN Giun san hoc la khoa hoc nghien cuu ve giun san ky sinh va nhung benh do giun san gay ra. Giun san la sinh vat da bao, co nhieu loai. Hien nay da biet hon 8000 loai song ky sinh d dong vat. Co nhieu loai co hai cho dong vat nuoi, co nhung loai khong gay hai, sinh song tu do. Giun san chia thanh 5 nganh sau: 1.1. Nganh San dep (Plathelminthes) Hai ben phai va trai doi xung nhau, hinh thai hoac hinh dai bang, luong tinh, co hoac khong co duong tieu hoa, khong co hau mon. Nganh san dep co hai lop gom nhieu giong, loai gay benh cho vat nuoi. * Ldp San la (Trematoda): Co the dep, hinh la, khong phan dot, co duong tieu hoa, thudng co 2 giac bam. * Ldp San day (Cestoda): Phan dot hoac khong, khong co he tieu hoa, tren dau co 4 giac bam hoac 2 ranh bam. 1.2. Nganh Giun tron (Nemathelminthes) Giun tron co duong tieu hoa, co hau mon, co giun cai va giun due rieng, co thi khong phan dot. Nganh nay co ldp Giun tron (Nematoda), co nhieu loai ky sinh d dong vat nuoi. 1.3. Nganh Giun dau gai (Acanthocephales) Dau co moc, khong co dudng tieu hoa. Chi co ldp giun dau gai (Acanthocephales) co mot so loai ky sinh d gia sue va gia chm. 1.4. Nganh Anelides Gom nhirng loai dia tu do sinh song, co the bam vao co the ngudi va gia sue di hut mau. 45 1.5. Nganh Vermides It lien quan toi chan nuoi thu y. Trong phan thu hai, chung toi chi tap trung vao 4 lop giun san gay tac hai cho gia sue, gia cam: Ldp Trematoda, Cestoda, Nematoda va Acanthocephala. 2. KHAI NIEM VA PHAN LOAI BENH GIUN SAN • • • 2.1. Khai niem Benh do cac loai giun san ky sinh gay ra d dong vat duoc goi chung la benh giun san. Nghien cuu ve giun san d cac mat: Hinh thai hoc, phan loai hoc, sinh thai hoc. Nghien cuu ve benh giun san d cac mat: Co che sinh benh, trieu chung lam sang, benh tich, dich te hoc, phuong phap chan doan va dieu tri. Tren co so do de ra bien phap phong tru tong hop. 2.2. Phan loai benh giun san Co the phan loai benh giun san can cu vao vong ddi phat trien cua giun san hoac vao bieu hien lam sang cua con vat. 2.2.1. Can cir vao vdng ddi giun san Skrjabin da dua vao qua trinh phat trien cua giun san can hay khong can ky chu trung gian va benh do chung gay ra, chia thanh hai loai: - Benh giun san truyen qua dat (benh giun san truyen true tiep) Nhung benh giun san trong qua trinh hoan thanh vong ddi cua giun san khong din ky chu trung gian duoc goi la benh giun san truyen qua dat. Trung, au trung cua chung phat trien ben ngoai, khong can ky chu trung gian da thanh trung hoac au trung gay benh, lan vao thuc an, nude uong vao duong tieu hoa ky chu ma thanh giun san trudng thanh. Vi du: Benh giun dua, benh giun toe, benh giun xoan da mui khi... - Benh giun san truyen qua sinh vat (benh giun san truyen gian tiep) Nhung benh giun san trong qua trinh hoan thanh vong ddi cua giun san cin phai co ky chu trung gian duoc goi la benh giun san truyen qua sinh vat. Vi du: Benh san la gan, benh san day ga, benh giun ph6 i Ion... Trong thuc tl, phong tru benh do giun san truyln qua ddt kho khan hon benh giun san truyen qua sinh vat bdi su de hoan thanh vong ddi cua chung. 2.2.2. Can cir vao trieu chung lam sang Erehov da can cu vao trieu chung lam sang d! chia thanh hai loai: - Khi con vat nhiem giun san nang, co trieu chung lam sang cua benh giun san (gay yeu, thieu mau, tieu chay, tham chi con vat chet) mdi goi la con vat bi benh giun san nay hay benh giun san khac. 46 - Khi con vat nhiem giun san nhe, khong co trieu chung lam sang thi chi goi la con vat mang giun san. Vi du: Be, nghe nhiem giun dua (Neoascaris vitulorum). Neu so luong giun nhieu, be, nghe co trieu chung dien hinh la ia chay, phan th6 i kham, mau trang, gay com... thi be, nghe do duoc goi la bj benh giun dua be, nghe. Nguoc lai, neu khong co trieu chung lam sang ro ret thi goi la con vat mang giun dua. Cach phan loai benh giun san tren day giup cac can bo thu y nhan thuc dung con vat nao bi benh giun san, tir do de ra bien phap phong trir thich hop. 3. PHlTONG PHAP CHAN DOAn BENH GIUN SAN Vi trieu chung lam sang cua benh giun san khong dien hinh nen viec chan doan benh giun san khac cac benh khac, do la: Phai tim thay can benh (trung, au triing hoac giun san truong thanh) moi co ket luan chinh xac ve benh. Thudng dua vao hai phuong phap: 3.1. Chan doan doi voi gia sue, gia cam song 3.1.1. Kiem tra giun san tru&ng thanh Co nhieu loai giun san ky sinh d duong tieu hoa, giun san trudng thanh hoac dot san theo phan ra ngoai. Kiem tra nhu sau: Lay phan cho vao chau, them 5 - 10 lan nude la sach, khuay ky cho tan phan, de yen cho phan lang xuong dudi, gan nude tren di, lai cho > > r r nude vao, rua di rira lai nhieu lan den khi nude trong suot thi duoc. Sau ciing gan nude di, cho can vao dia thuy tinh ldn mot nira son den, mot nira trang, roi tim giun san. Neu co giun san thi dung but long hoac long ga khoi ra. Neu giun san qua nho thi soi qua kinh lup de tim. 3.1.2. Kiem tra tr intg giun san Hinh 1. Xet nghiem trung giun san trong phan Hinh 2. Kinh hi in vi 47 Co nhung phuong phap phat hien trung giun san trong phan. Cac phuong phap thudng su dung gom: * Phuang phap true tiep: Nho tren phien kinh mot giot dung dich glyxerin 50% (neu khong co dung dich glyxerin thi dung nude la sach cung duoc, glyxerin giu cho tieu ban khong bj kho, trong su6 t de tim). Dung dua thuy tinh liy mot luong phan bang hat dau, hoa tan dlu vdi dung djch glyxerin, gat can ba di, day la kinh len, soi kinh hien vi tim trung va au trung (do phong dai 1 0 x 1 0 ). Phuong phap nay don gian, de lam nhung do chinh xac kem. Khi con vat nhiem nhe, moi lan kiem tra phai lam 5 - 7 phien kinh mdi tim thay trung, au trung. > ; I ♦ * * ■ * * € , Hinh 3. Lam tieu ban mau phan bang phucrng phap true tiep * Phuang phap phu noi: Ngudi ta loi dung ty trong cua mot so dung djch ldn hon ty trong cua trung giun san, lam cho trung giun san noi len tren, khi kiem tra de tim thay trung. Thudng dung cac phuong phap sau: - Phuang phap Fulleborn (Fiileborn): Hieu qua tot, de ap dung rong rai trong san xuat, kiem tra duoc trung cua nhieu giun tron va san day. Cach pha nude muoi bao hoa: Vua dun soi 1 lit nude vua cho 400 gam mu6 i NaCl vao (hoac dun soi mot luong nude bat ky va cho tu tir mudi vao), khuiiy dlu din khi muoi khong tan duoc nua, khi de nguoi tren mat co ldp muoi kit tinh la duoc. Loc qua vai man hoac bong, bo can. Cach lam: Lay 5-10 gam phan cho vao mot c6 c nho, dung dua thuy tinh nghiln nat, vira nghien vira do nude muoi bao hoa vao, khoang 40 - 50 ml, sau do loc qua ludi thep bo can, cho nude loc vao coc nho, d! yen 20 phut - 30 phut, trung giun san se n6 i len tren. Dung vong thep co duong kinh 3 - 5 mm vdt ldp mang mong n6 i tren b! mat, cho len phien kinh, day la kinh, soi kinh hiln vi. Cung co th i cho nude loc vao cac lo nho cho day len den mi?ng, day phien kinh len mat lo cho tilp xuc vdi mat nude, d l yen 20 - 30 phut roi lay phien kinh ra soi kinh hien vi. Mu6 n nang cao hieu qua cua phuong phap nay, co thi thay dung djch nude muoi bao hoa bang cac dung djch bao hoa khac co ty trong cao hon (vi du: Dung djch natri hyposunfit: 1 lit nude + 1.750 gam, hoac dung djch natri nitrat: 1 lit nude + 1.000 gam, hoac dung djch magie sunfat: 1 lit + 920 gam). 48 1. Cho v&o c6c dung djch NaCl bao h6a 5-10 gam phan 2. KhuSy tan phan 3. Lpc bo bdt can 4. Cho nu6c lpc v^o lp nho, day phien ki'nh len, 5. Lay phiSn kinh ra, soi kinh hiSn vi de yen 20 phut tim trung giun tron Hinh 4. Cac buoc thuc hien phuong phap Fulleborn - PItu-ong phap Darling: Hoa tan 5 - 10 gam phan voi nuoc la, loc qua luoi thep bo can, roi quay ly tam nuoc loc. Ty trong cua trung nang hon ty trong cua nuoc la se lang xuong day, gan tu tir nuoc 6 tren, giu lai can roi cho dung dich muoi NaCl bao hoa vao, dung dua thuy tinh khuay deu, lai ly tam lan nua, trung se noi len tren. Dung vong thep vdt lop mang noi tren be mat dung dich dat len phien kinh, day la kinh, soi kinh hien vi tim trung giun tron. Phuong phap nay tot hon phuong phap Fulleborn vi co the tim thay trung cua nhieu loai giun tron, co the tim thay ca trung san day. Hinh 5. Ly tam phan trong dung dich NaCl bao hoa de tim trung giun tron 49 - Phuang phap Cherbovick: Phuong phap nay t6 t hon 2 phuong phap tren, co the tim thay trung giun dau gai, ca trung giun phoi Ion, cac loai trung giun tron, co the thay ca trung cua mot so san la co kich thuoc nho. Cho 5-10 gam phan vao coc thuy tinh dung tich 100 ml, them 30 - 50 ml nuoc la, khuay tan, loc qua ludi thep, cho vao ong ly tam quay ly tam, gan do tir tu nuoc d tren di, roi cho dung dich bao hoa vao. Tiiy theo muc dich chan doan ma dung dung djch khac nhau. Neu tim trung giun phoi Ion thi dung dung djch MgSC>4 bao hoa, neu tim trung giun dau gai thi dung dung dich natri hyposunfit bao hoa. Lac manh hoac lay dua thuy tinh khuay deu, ly tam 3 phut. Dung vong thep vot mang noi len tren, cho len phien kinh, day la kinh, soi duoi kinh hien vi. * Phuang phap gan rira sa long (doi rua nhieu tan): Muc dich tim trung cac loai san la co ty trong lcrn hon ty trong cua cac dung dich bao hoa. Cho mot luong phan bang qua bong ban vao coc thuy tinh ldn co gap 10 lan nude la; khuay manh cho tan phan; loc qua ludi loc vao mot binh tam giac, de yen 20 - 30 phut cho can lang xuong, gan nude d tren di, lai cho nude vao, de yen 20 - 30 phut cho r * r ' \ \ r r lang can xuong... Lam lien tuc nhieu lan cho den khi nude trong suot, gan nude di, cho can vao dia petri soi kinh hien vi tim trung san la. 1. Cho phan v&o c6c dung nuoc 13 sach 2. KhuSy cho tan phan 3. Loc bo bat can 4. De yen 20 - 30 phut 50 5. De ling can 6. Gan tu tir giu lai c2n Hinh 6. Cac buoc trong phucmg phap gan rira sa lang * Phuang phap dem trung Stoll: Muc dich de danh gia muc do cam nhiem va danh gia hieu qua cua mot loai thuoc tay giun san. Phuong phap nay chi giup ta danh gia mot each khai quat muc do cam nhiem, khong the chinh xac tuyet doi duoc. Lay mot binh dong co vach 100 ml, cho vao do 56 ml dung dich NaCl 0,1N, sau do cho phan vao tir tir den khi dung dich toi vach 60 ml (tuc la da cho vao 4 gam phan). Sau do cho vao binh 10 vien bi thuy tinh, lac manh roi lay ong hut 0,15 ml chia deu tren phien kinh lam hai phan, day la kinh, dem duoi kinh hien vi. So trung dem duoc x 60 So trung/g phan 0,15 : 4 = so trung dem duoc x 1 00 * Phuang phap dem trung Me. Master Phuong phap nay dung de xac dinh so luong trung giun tron, trung san day va Oocyst cau triing trong 1 gam phan bang buong dem Me. Master. Can 4 gam phan vao coc thuy tinh, them 56 ml dung dich nuoc muoi bao hoa, khuay deu cho tan phan. Loc qua ludi thep vao mot coc khac va khuay deu. Trong khi dang khuay, lay cong to gut hut dung djch phan nho day ca hai buong dem Me. Master (moi buong dem co dung tich 0,5 ml). De yen 15 phut roi kiem tra duoi kinh hien vi (do phong dai 10 x 10). Trong thuc te, de de phat hien va de dem trung, co the cai tien nhu sau: + Buoc 1: Can 4 gam phan vao coc thuy tinh, them nuoc la sach (khoang 100 - 150 ml), khuay tan phan, loc bo can ba tho. Nuoc loc de lang trong 1 - 2 gid, gan bo nude, giu lai can. + Buoc 2: Cho 56 ml dung dich nude muoi bao hoa, khuay deu cho tan can. Trong khi dang khuay, lay cong to gut hut 1 ml dung dich phan nho day 2 bu6 ng dim Me. Master. De yen 15 phut roi kiem tra duoi kinh hien vi (do phong dai 10 x 10). Dim toan / > r > bo so trung trong nhung o cua hai buong dem, roi tinh theo cong thuc sau: 51 1. Cho 4 gam phan vao coc thuy tinh 2. Them 56 ml dung djch mu6i bao hda 3. Khuay tan phan 4. Lpc b6 b6t can 5. Khuay dung djch phan va hut bang cong to gut 6. Nho dung djch phan vao day hai buong dem, de yen 15 phut r6i d€m du6i kinh hi£n vi (x 100) Hinh 7. Cach tien hanh phuong phap dim trimg Me. Master ■» ' ■y f So trimg/gam phan = Tong so trimg cr hai buong dem x 60 ? r \ r r (Tong so trumg o hai buong dem la so trung co trong 1 ml dung dich phan) 52 1. Fasciola hepatica 2. Paramphistomum cervi 3. Thysaniezia o villa 4. Moniezia expansa 5. M benedeni 6. Dicrocoelium 7. Strongyloides papillosus 8. Gongylonema pulchrum 9. Trichuris globulosa 10. Fasciola gigantica 11. Nematodirus spathiger 12. Gaigeria pachysee Us 13. Trichostrongyluss’p. 14. Skrjabinema ovis 15. Avitellina centripunctata 16. Chabertia ovina 17. Haemoch us con tortus 18. Bunostomum trigonocephalum 19. Oesophagostomum columbianum 20. Cotylophoron cotylophorum 21. Fascioloides magna 22. Ostertagia circumcinata 23. Coo peri a sp. 24. Neoascaris vitulorum Hinh 8. Trung giun san ky sinh a gia sue nhai lai 1. Parascaris equorum 2. Strongylus spp. 3. Trichonema spp. 4. Triodontophorus tenuicollis 5. Anoplocephala spp. 6. Gastrodiscus aegyptiacus 7. Strongyloides westeri 8. Dictyocaulus arnfieldi 9. Oxyuris equi 10. Paranoplocephala mamillana 11. Habronemaspp. 12. Fasciola hepatica Hinh 9. Trung giun san ky sinh a ngua 53 T TOO urn w 7 1. Ascaris suum 2. Fasciola hepatica 3. Paragonimus sp 4. Ascarops strongyUna 5. Stephanurus dentatus 6. Trichocepha/us suis 7. Metastrongy/us sp 8. Oesophagostomum detatum 9. Hyostrongy/us rubidus 10. Physocepha/us sexa/atus 11. Brachytaemus sp. 12. Macracanthorhynchus birundi neceus 13. Globocephalus sp 14. Schistosoma suis Hinh 10. Trimg giun san ky sinh a lorn 1. Ascaridia galli 2. Heterakis gal Una rum 3. Subulura brumpti 4. Prosthogonimus sp. 5. Strongyloides avium 6. Tetrameres ameriacana 7. Acuaria spiralis 8. Acuaria bamulosa 9. Gongylonema ingluvicola 10. Syngamus trachea 11. Hartertia gall in arum 12. Oxyspirura mansoni 13. CapiHaria annulata 14. Capillaria retusa 15. Capillaria columbae 16. Capillaria longicollis Hinh 11. Trimg giun san ky sinh a gia cam •7 r 3.1.3. Phuang phap kiem tra au trung giun san - Phuang phap Baerman: Lay 15-20 gam phan cho len pheu co ludi thep, diu pheu noi voi mot dau ong cao su dai 15-20 cm, dau kia noi voi ong nghiem, de pheu len tren gia, cho nuoc nong 40°C vao trong pheu cho den khi nuoc nong phu kin phan. De yen 1 - 2 gid, au trung se bo ra khoi phan va lang xuong day ong nghiem, lay nude d ong nghiem dem ly tam, lay can soi kinh hien vi tim au trung roi can cu vao hinh thai, kich thudc au trung ma chan doan benh. 54 1. Dyng cy Baerman 2. Lay 10 - 15 g phan cho v&o 3. Bupc mpt que thuy tinh nho v&o manh vdi gac, buoc turn lai mi?ng turn phan 4. D5t turn phan v&o pheu 5. R6t nude am vdo pheu cho ngap turn phan 6. De yen 1 - 2 gid 7. LSy 6ng nghiem ra, de yen 30 phut 8. Gan nuoc trong a tren 9. D6 can vao hQp long, lin g mong va soi dudi kinh hien vi tim au trung Hinh 12. Cach tien hanh phucrng phap phan ly du triing Baerman 55 - Phuang phap Vaida: Dung chan doan benh giun tron 6 duong tieu hoa va duong ho hap cua de, cuu, huou vi phan cua Chung tron va kho. Lay 3 - 4 vien phan cho vao dia petri co nuoc nong 40°C, sau 5-10 phut, au trung bo ra, gat bo vien phan di, soi kinh nuoc 6 tren dia petri tim au trung. - Phuong phap nuoi au trung: Co nhieu loai trung giun tron, nhat la trung giun xoSn thupc bp phu Strongylata \e hinh thai rat giong nhau nen kiem tra trung khong the phan biet duoc, vi vay phai nuoi trung no thanh au trung cam nhiem roi can cu vao hinh thai au trung ma chan doan. Lay phan cho vao dia petri, neu phan kho thi cho them mot it nuoc, tron deu vun thanh hinh chop, dinh cua dong phan vua cham nap tren hop long, cho vao tu am 25 - 30°C, neu la mua he thi de 6 trong phong cung duoc. Giu cho phan luon co do am nhat dinh (cach 1 - 2 ngay cho them it nuoc). Nuoi khoang 7 ngay thi trung giun xoSn no va phat trien thanh au trung cam nhiem. Au trung nay thuong tap trung 6 nhung giot nuoc boc hoi tren nap dTa petri. Lay ong hut, hut nuoc cho len phien kinh, kinh hien vi tim au trung. Co the lay phan nay kiem tra au trung bang phuong phap Baerman. Hinh 13. Cac dang du trung cam nhiem cua bo Strongylida 1 - Haemonchus contortus', 2 - Cooperia\ 3 - Trichostrongylus', 4 - O stertagia\ 5 - Chabertia\ 6 - Oesophagostomum columbianum\ 1-0. \enulosum \ 8 - Bunostomum\ 9 - Nematodirus (theo Poliakov, 1953). 56 3.1.4. Phuang phap chan doan mien dich Co nhieu loai giun san sau khi vao co the se kich thich co the san sinh khang the. Khang the se ket hop voi khang nguyen tuong ung sinh ra cac phan ung dac hieu. Can cu vao phan ung nay nguoi ta co the dung phuong phap mien dich de chan doan benh giun san. Thuong dung trong chan doan benh ken nuoc, benh au san nhieu dau, benh san la gan, benh giun than Ion, benh giun dua... Khang nguyen chan doan co the che tir giun san truong thanh, au triing hoac dich trong co the au triing. Co the pha loang khang nguyen thanh cac nong do tir 1/5.000 - 1/10.000. Timg loai giun san co tinh dac hieu rieng, nhung van con hien tuong phan ung gia hoac phan ung cheo. Co the dung khang nguyen tiem trong da, tiem duoi da, r f f i t nho mat, lam phan ung lang can, phan ung ket hop bo the... nhung thudng dung phuong phap tiem trong da. Lieu khang nguyen thuong dung tiem trong da la 0,1 - 0,5 ml, sau khi tiem 3-15 phut, theo doi sir bien doi o cho tiem. Neu cho tiem sung to, xung quanh do, duong kinh 0,2 - 4 cm thi la duong tinh, nguoc lai la am tinh. 3.2. Chan doan doi voi gia sue, gia cam da chet Phuong phap chan doan sau khi con vat chat la chinh xac nhat. Phuong phap nay co the phat hien duoc tat ca cac loai giun san o tat ca moi khi quan, to chuc cua dong vat (ke ca giun san rat nho). Tir do, co the danh gia duoc ty le va cuong do cam nhiem giun san, dinh loai giun san. Do do, phuong phap chan doan nay co y nghTa Ion trong cong tac nghien cuu, dong thoi lam co so khoa hoc cho cac bien phap phong trir thich hop. 3.2.1. Phuang phap mo k/tdm sau khi con vat chet (thuong dung 3 phuong phap) •> r * Phuang phap mo kham toan dien cua Skrjabin: Muc dich la tim tat ca moi loai giun san 6 tat ca cac khi quan trong co the dong vat. Truoc tien lot da, xem ky to chuc duoi da, lay cac khi quan ra. Chu y khong lam r6 i loan cac khi quan. Tach cac khi quan tieu hoa, bai tiet, ho hap, sinh due, tim va cac dong, tinh mach Ion. Sau do kiem tra ky xoang nguc va xoang bung, lay nuoc trong cac xoang nay cho vao binh de kiem tra. Lay tuy song, kiem tra djch trong mat, kiem tra dich o khop xuong, 6 xoang mat. Kiem tra luoi, moi, roi kiem tra lam lucrt cac co quan: - Khi quan tieu hoa: Buoc chat de tach rieng cac bo phan (thuc quan, da day, ruot non, ruot gia, manh trang, gan, tuyen tuy) roi tach ra va cho rieng vao thiing hoac chau. r t f f Thuc quan: Dung keo cat doc thuc quan. Kiem tra ky niem mac. Neu thay sung hoac co mu thi kiem tra noi do. Sau do dung phien kinh nao niem mac thuc quan r6 i ep chat nao giua hai phien kinh trong suot, soi kinh hien vi hoac kinh lup. NSu co giun san thi dung but long hoac kim lay ra. Da day: Cat doc theo chieu cong cua da day, lay chat chua cho vao thiing, dung nuoc rira thanh da day, nuoc rira va chat chira cho vao voi nhau, dung dua khuay doi / t f t r \ lang can gan nuoc tren di, lai cho nuoc vao, khuay, de yen, doi lang can roi gan nuoc 57 di... Lam nhieu lan toi khi nude trong suot la dugc, gan nude tren di, lay can soi ki'nh lup tim giun san. Ruot non, ruot gia va manh trang (kiem tra rieng ba bo phan): Dung keo cat doc theo chieu cong cua ruot, dung phuong phap gan rua sa lang, tim giun san trong chat chua d moi bo phan. Dong thoi dung phien kinh nao niem mac, ep kinh kiem tra. Gan: Tach mat cho vao hop 16ng d8 kilm tra rieng bang phuong phap gan rua sa lang dich mat. Dung tay bop nat gan roi gan rua sa lang de kiem tra. Tuyen tuy: Cung lam nhu gan. - Khi quan ho hap: Dung keo cat hau, khi quan va chi nhanh khi quan. Sau do nao niem dich soi kinh lup. Bop nat phoi cho vao nuoc, dung phuong phap gan rua sa lang de kiem tra giun san. - Khi quan bai tiet: Cat than lam doi, dung m it thudng kiem tra be than va xung quanh be than, sau do nao vet be than de kiem tra, lay to chuc than ep len phien kinh, soi kinh lup. Cat dgc ong dan nuoc tieu va bang quang roi kiem tra nuoc tieu bang phuong phap gan rua sa lang. Nao vet niem mac duong tiet nieu de ep kinh, soi kinh lup tim giun san. * Phuang phap mo kham toan dien mot ca quan: Co nhieu y nghTa thuc tien. Muc dich tim moi loai giun san ky sinh d mot co quan, con cac co quan khac khong can kiem tra. * Phuang phap mo kham khong toan dien: Muc dich biet ty le va cudng do nhiem mot loai giun san nao do. Vi du: Nghien cuu ty le va cudng do nhiem giun dua d lgn nuoi tai tinh Thai Nguyen (chi mo kham de tim giun dua A. suum trudng thanh d ruot non va tim au trung d phoi). 3.2.2. Phuang phap thu luam va ngam giu giun san Dung kim giai phau hoac but long de lay giun san (khong dung vat cung). D6 i vdi san la va san day thi de chung chet tu nhien trong nude la, sau do dem rua sach va ep mong giua hai phien kinh roi dat trong dTa petri hoac binh thuy tinh co nut mai, chua con 70°. Khi ep mong san day chi can ep mong cac dot than, con dhu thi khong ep. Thoi gian ep dai ngan tuy san day hay mong, co th6 ep 1 ngay hoac 1 gid. Sau khi ep chuyen sang cac ong nghiem co con 70° va ghi nhan. Doi vdi giun tron, rua sach bang nude la r6 i bao quan trong dung dich Barbagallo (formon 30 ml, NaCl tinh khiet 7,5 gam, nude cit 1000 ml). Doi vdi giun dau gai: Bao quan trong c6 n 70°. Ghi nhan kem theo giun san chua dinh loai: Ten ky chu, tinh biet, so md kham, noi co giun san, so bo phan dinh loai, so lugng giun san. Mat sau ghi: Dia dilm, ngay thang, ten ngudi mo kham. 58 Cfutmig 4 SAN LA VA MOT SO BENH SAN l A 1. DAC DIEM HiNH THAI, CAU TAO VA VONG DCfl CUA SAN l A 1.1. Dac diem hinh thai, cau tao Phan Ion san la dep theo huong lung bung, hinh la, co khi hinh tru, hinh chop non, hinh long mang. Co mau hong, xam hay trang nga. Ben ngoai than nhan hoac phu gai, vay va co nhung giac bam. Thudng co hai giac bam: Giac mieng va giac bung. Giac mieng dung de bam va hut cac chat dinh duong nuoi co the. Day giac mieng la lo mieng thong voi he tieu hoa. Giac bung thudng d khoang giua bung hoac d ngay dau, gan giac mieng, hoac d phia tan cung cua san. Vi du: San la Fasciola, Fasciolopsis giac bung d gan giac mieng, san Prosthogonimus giac bung d gan giua than; san Paramphistomum giac bung nam d gan cuoi than san. Giac bung chi dung de bam vao vj tri ky sinh. Mot so loai san la khong co giac bung (Monostomidae) hoac co giac bam thu ba - giac sinh due (Strigeidae). San la co lo sinh due d canh giac bung va lo bai tiet d cuoi than san. Kich thudc san la thay doi tuy theo loai. Chieu dai san tu 0,1 mm den hon 150 mm, co san dai tdi 1 m (Nemathobothrium filarina ky sinh d ca map). Ve cau tao: Ben ngoai than san la ldp mang che phu roi den nhung bo co vong, co doc, tiep theo la mang day. Mang che phu cung vdi he co tao thanh tui bi co va chua cac khi quan ben trong. - He tieu hod: Lo mieng d day giac mieng, thong vdi hau hinh bau due. Sau hau la thuc quan noi vdi ruot. Ruot phan thanh hai nhanh va bit kin d cuoi goi la manh trang. Manh trang thudng la ong thang hoac uon cong gap khue, co khi phan nhanh va nam r \ r r doc hai ben than. San la song bang niem dich, duong chat. Mot so loai hut mau ky chu. San pham cua qua trinh trao doi chat thai ra ngoai qua he thong bai tiet. Can ba cua qua trinh tieu hoa thai ra ngoai qua mieng do manh trang nhu dong nguoc tro lai. - He bai tiet: La mang ludi phuc tap nhung ong nho, phan bo doi xung d ben than, thong vdi ong dan chung roi do vao hai ong dan chinh d hai ben than, hai ong nay hop thanh tui bai tiet d cuoi than va thong ra ngoai qua lo bai tiet. - He than kinh va ca quan cam giac: He than kinh gom hai hach nao nam hai ben hau, noi vdi nhau bang vong day than kinh, tir hach nao co ba doi day thin kinh di ve phia trudc va sau than. Nhung day than kinh nay noi vdi nhau bang nhieu day nho. Co quan cam giac d san trudng thanh bi tieu giam. 6 mao au (Miracidium) va vi Su (Cercaria) cua nhieu loai san la van con dau vet cua mat. 59 - He tuan hoan va ho hap: Hoan toan bi tieu giam. - He sinh due: Phat trien manh. Hau het san la co cau tao co the luong ti'nh. Co quan sinh due due gom hai tinh hoan to, hinh khoi tron hay bau due, co khi phan thuy hoac phan nhanh, xep tren duoi nhau hoac doi xung hai ben than. Moi tinh hoan thong voi mot ong dan tinh rieng, roi hop thanh ong chung thong voi tui sinh due. Phan ong dan tinh chung nam trong tui sinh due duoc kitin hoa goi la cirrus. Cirrus thong ra ngoai lo sinh due due 6 bung san va dung de giao phoi. Xung quanh cirrus co tuyen tien liet bao boc. Co quan sinh due cai gom: O trung (Ootype) thong voi tir cung, tuyen Me hi is, tuyen noan hoang, buong trung va tui chira tinh. O trimg thuong nho hon tinh hoan, la noi trung hinh thanh va thu tinh. Buong trung hinh khoi tron hoac phan thuy, co khi phan nhanh. Tui chua tinh chua tinh djch du tru. Tir cung la ong dan uon khue, chua d£y trung da thu tinh, mot dau tir cung thong voi o trung, dau con lai thong ra ben ngoai qua lo sinh san cai 6 mat bung. Tuyen Mehlis tiet dich the lam tron 6 trung va tu cung, giup trung lot Hinh 14. Hinh thai cau tao san la (Trematoda) 1- Giac mieng; 2- Truoc hau; 3- Hau; 4- Thuc quan; 5- Gai sinh due; 6- Giac bung; 7- Doan cuoi cua tu cung; 8- Tuyen no2n hoang; 9- Ong Laurer; 10- Ootype; 11- Ruot; 1 2 -Tinh hoan; 1 3 -Tui bai tiet; 1 4 -Tir cung; 15- Ong dan tinh; 16- The Mahlis; 1 7 -Tui nhan tinh; 1 8 - Buong trimg; 19- Tui chira tinh; 20- Tuyen sinh due phu; 21- Tui sinh due vao tir cung va thai ra ngoai de dang, dong thoi giup tinh triing hoat dong manh hon. Tuyen noan hoang phan bo doc hai ben than san va tao ra chat dinh duong nuoi trung. O trung con thong voi ong Laurer, ong nay thai noan hoang thira tir 6 trung ra ngoai d£ trung hinh thanh thuan loi. Lo sinh due due va cai d gan nhau, thuong 6 truoc giac bung, co khi 6 han phia dau san (.Prosthogonimus). San la giao phoi bang hai cach: Tu thu tinh va thu tinh cheo. ' ' ' * r * Trung san la hau het co hinh bau due, mot dau co nap, ben trong chua nhieu phoi bao. Vo trung gom bon lop, ba lop ngoai co tac dung bao ve trung ve mat co hoc. lop thir tu co tac dung bao ve trung ve mat hoa hoc. 60 1.2. Vong doi cua san la Hau het san la ky sinh d gia sue, gia cam deu la nhirng san can ky chu trung gian. San truong thanh ky sinh d ky chu cuoi ciing, giai doan au triing song va phat trien trong ky chu trung gian va ky chu trung gian bo sung. Trong ky chu trung gian, au triing phat trien qua cac giai doan va tien hanh sinh san vo ti'nh. CJ ky chu cuoi ciing, san la sinh san huu ti'nh va thai trung da thu tinh ra moi trudng. Moi loai san la co vong doi rieng, nhung nhin chung vong doi cua cac san la ky sinh d gia sue, gia cam nhu sau: San trudng thanh ky sinh d ky chu cuoi ciing, thu tinh va de trung. CJ moi trudng ben ngoai, gap dieu kien thi'ch hop (t°, pH, anh sang, do am...) phoi trong trung phat trien thanh mao au (Miracidium), mao au thoat vo ra ngoai boi trong nude (mao au hinh tam giac, co mat va nhieu long nho bao phu ngoai co the), mao au chi ton tai mot vai ngay. Trong thoi gian nay no tich cue tim ky chu trung gian de xam nhiem. Vao ky chii trung gian, mao au rung long va bien thanh bao au (Sporocyst). Bao au co hinh mot cai y r r \ bao, trong chua nhieu te bao. Sau mot thoi gian, bao au sinh san vo ti'nh cho ra nhieu loi au (Redia). Redia co lo mieng, hau, te bao mam cua ruot va te bao phoi. Redia tiep tuc sinh san vo ti'nh cho ra nhieu vi au (Cercaria). Khi da phat trien day du (co giac mieng, giac bung, hau, thuc quan, manh trang, duoi...), vT au chui ra khoi ky chii trung gian. Hinh 15. Cac dang du trung cua san la Trematoda 1. Miracidium 2. Sporocyst 3. Redia 4-6. Cercaria 7. A dolescaria - V&i san la can mot ky chu trung gian: VT au rung duoi, tiet dich thi bao boc quanh than va bien thanh. Neu sue vat nuot phai thi trong co the sue vat, Adolescaria tiep tuc phat trien thanh san la trudng thanh. ^ r - V&i nhirng san la can 2 ky chu trung gian: Cercaria tiep tuc xam nhap vao ky chu trung gian thu hai - ky chu trung gian bo sung va bien thanh Metacercaria. Khi sue 61 vat nuot phai ky chu trung gian bo sung thi Metacercaria se phat trien thanh san trudng thanh trong co the sue vat. San la trudng thanh ky sinh d nhieu noi trong co the sue vat: Ong mat, gan, da day, ruot, tuyen tuy, ong dan trung, lo huyet, ph6 i va mot so khi quan khac. Hinh 16. Miracidium va Cercaria cua san la Fasciola spp. 2. BENH SAN LA THUttNG GAP O GIA SUC, GIA CAM 2.1. Benh san la gan ff sue vat nhai lai (Fasciolosis) 2.1.1. Can benh, ky chu va vi tri ky sinh - Can benh: La hai loai san la Fasciola hepatica va Fasciola gigantica. - Ky chu: Trau, bo, de, cuu. Cung thay d Ion, ngua, tho, mot so dong vat hoang dai va ca d ngudi. Ky chu trung gian: Oc nude ngot Lymnaea auricularia, L. swinhoei, L. viridis, Radix ovata... - Vj tri ky sinh: Thudng ky sinh d ong dan mat, co khi thay ca d phoi, tim, hach lam ba, tuyen tuy sue vat. * CJ Viet Nam, benh chu yeu do loai F. gigantica gay ra. Ky chu trung gian cua san la gan d mien Bac Viet Nam la hai loai oc nude ngot: Lymnaea swinhoei (oc vanh tai) va L. viridis (oc chanh) (Phan Dich Lan va cs, 1985). 2.1.2. Dac diem hinh thai can benh • • - F. gigantica (Cobbold, 1885): Dai 25 - 75 mm, rong 3-12 mm, hinh la, hai mep ben gan nhu song song, khong co “vai”, cuoi than hoi tu. Co hai giac bam: Giac mieng d phia trudc than, giac bung d gan giac mieng va ldn hon giac mieng. Lo mieng d day giac mieng thong vdi hau, thuc quan, ruot g6 m hai manh trang phan thanh nhilu nhanh nho. He sinh due: San la gan ludng tinh. Hai tinh hoan phan nhanh manh, xep tren dudi nhau d phan sau co the. Lo sinh san d phia trudc giac bung. Buong trung phan nhanh d 62 phia truoc tinh hoan. Tu cung uon khue thanh hinh hoa 6 giua ong dan noan hoang va giac bung. Tuyen noan hoang xep doc hai ben than va phan nhanh. San truong thanh co the tu thu tinh va thu tinh cheo. Trung san hinh bau due, phinh rong o giua, thon dan ve phia hai dau, dau hoi nho hon co nap trung. Kich thuoc trung: Dai 0,125 - 0,170 mm, rong 0,06 - 0,10 mm. Trung mau vang nau, phoi bao phan bo deu va xep kin vo. - F. hepatica (Linnaeus, 1758): Dai 18-51 mm, rong 4-13 mm, mau nau nhat. Phan dau hinh non dai 3 - 4mm, chua ca hai giac bam, giac bung Ion hon giac mieng. Phia truoc than phinh to, thon nho dan ve phia cuoi than san tao thanh “vai”. Cau tao co quan ben trong cua F. hepatica tuong tu F. gigantica. Trung san dai 0,13 - 0,15 mm, rong 0,07 - 0,09 mm. F. gigantica F. hepatica Tieu ban san F. hepatica nhuom carmin Trung F asciola gigantica Hinh 17. San va trung san la Fasciola spp. 2.1.3. Vong ddi Fasciola truong thanh ky sinh trong ong dan mat cua trau, bo, de, cuu va mot s6 sue vat khac. Sau khi thu tinh, moi san de hang chuc van trung. Trung theo dich mat vao ruot roi theo phan ra ngoai. Gap dieu kien thuan loi (t° =15- 30°C, pH = 5 - 7,7, co anh sang, trong moi truong nuoc sau 10 - 25 ngay trong trung hinh thanh Miracidium. Duoi 63 tac dong cua anh sang, Miracidium day bat nap trimg thoat ra ngoai va ben tu do trong nuoc (nlu thilu anh sang, Miracidium khong co kha nang thoat khoi vo trung, nhung van t6 n tai din 8 thang trong vo trung). Miracidium dai 0,19 mm, rong 0,026 mm, co kha nang t6 n tai trong nuoc khong qua 40 gia. Nlu gap ky chu trung gian la oc Lymnaea auricularia, L. viridis, L. swinhoei, Radix ovata... Miracidium xam nhap vao co thi 6 c, di chuyln vao gan, mat long va phat trien thanh Sporocyst dai 0,15 mm. Sau 15-30 ngay, Sporocyst sinh san vo tinh thanh 5-15 Redia. Sau 32 - 40 ngay, moi Redia dai 1 mm va co the sinh ra 15 - 20 Cercaria. Ba lo&i 6c Lymnaea spp. tim thly a Vi?t Nam M iracidium thodt v6 de tim ky chu a. L. viridis b. L. swinhoei c. Lymnaea spp. trung gian Oc L. swinhoei thuong s6ng a ao rau muong Oc Lym naea spp. nhieu nu6c trong, tinh Hinh 18. Cac loai oc Lymnaea spp. - Ky chu trung gian cua san la Fasciola d Viet Nam Tu khi Miracidium vao oc den khi phat trien thanh Cercaria can khoang 30 - 60 ngay. Luc nay Cercaria qua mieng oc ra moi truong ngoai co kich thuoc 0,28 - 0,3 mm chieu dai va 0,23 mm chieu rong. Moi oc co the mang 600 - 800 Cercaria. Sau vai gio bai loi trong nuoc, Cercaria rung duoi, tiet ra chat nhan, dinh xung quanh than. Sau vai phut, chat nhan dong dac lai thanh vo boc chic chin, mau nau hung, duong kinh 0.2 - 64 0,25 mm. Luc nay Cercaria da bien thanh Adolescaria, la limg trong nuac hoac bam vao cay co trong vung am thap lay loi. Hinh 19. Cac dang du trung cua san Fasciola 1 a. Miracidium nd ra tu trung san lb. Sporocyst 2a. Redia non 2b. Redia gid cd C ercaria non 3 a. Redia me ph6ng ra nhieu Redia con 3b. Cercaria au trung sdn Id gan chui khoi oc 4a. Cercaria rung duoi tao thanh ken 4b. Adolescaria cua san la gan V0NG1VI san la gar? Hinh 20. Vdng dai phat trien cua san Fasciola 1. Trung no thanh M iracidium trong nuoc 2. Miracidium vao oc - vat chu trung gian 3. Cercaria rdi khoi oc 4. Adolescaria bam tren cay co thuy sinh 5. Sue vat nhai lai nuot A dolescaria 6. Fasciola trudng thanh ky sinh trong ong dan mat 8 ♦ 4 1 ! — % I i \ \ * f NSu trau, bo, de, cuu nuot phai thi Adolescaria vao ong tieu hoa, vo ngoai bi phan huy, au trimg duoc giai phong va chuyen den ong mat bang hai cach: 65 - Mot so au trung dung tuyen xuyen qua niem mac nipt vao mau, roi tinh mach cua, vao gan, xuyen qua nhu mo gan vao ong dan mat. - Mot s6 Au trung khac dung tuyen xuyen chui qua thanh ruot vao xoang bung, den gan, xuyen qua vo gan vao ong dan mat va phat trien thanh san la truong thanh. Tu khi sue vat nuot Adolescaria den khi phat trien thanh san truong thanh can thoi gian tir 3 - 4 thang. San trudng thanh co thi ky sinh d ky chu tori 3 - 5 nam, co khi toi 11 nam. 2.1.4. Dich te hoc Benh phan bo khap cac vung trong nuoc. Sue vat 6 vung dong bang va trung du nhiem nhieu va nang. Sue vat d mien nui va ven bien nhiem it hon. Gia sue nhai lai nhiem san la gan kha pho bien. Theo Trinh Van Thinh (1978), trau, bo nhiem san la gan 50 - 70%. Theo Phan Djch Lan (1980), ty le nhiem san la gan 6 trau d huyen Binh Luc - Ha Nam la 51,2 - 57,5%; Nguyen Thi Kim Lan (2000) cho biet: Dan de dia phuong d cac tinh Thai Nguyen, Bac Kan, Tuyen Quang, Cao Bang nhiem san la gan bien dong tir 5,3 - 27,9% tiiy dia phuong. \ i r y Viing lay loi, am thap benh san la gan phat ra nhieu. Ky chu trung gian giup au triing phat trien va lam tang gap boi so luong au triing. Tuoi sue vat cang cao thi ty le va cudng do nhiem cang tang. Nhung nam mua nhieu, sue vat nhiem san la gan nhieu hon nhung nam kho han. Vu He - Thu ty le nhiem tang so vdi vu Dong - Xuan. Trung san de chet d dieu kien kho han va anh sang mat trdi chieu true tiep. C) dieu kien am udt, trung co the ton tai tdi 8 thang. Adolescaria co sue de khang cao, ton tai dupe d nhiet do - 4°C den - 6 °C. O nhiet do binh thudng, Adolescaria co the ton tai tren 5 thang (Kaufmann J., 1996). 2.1.5. Co che sinh benh Khi sue vat mdi nhiem benh, san non di hanh lam ton thuong thanh ruot, thanh mach mau, nhu mo gan, lach, phoi, co hoanh, tuyen tuy, gay xuAt huylt nang hoac nhe. Thudng gay viem gan, thieu mau do xuat huyet, co khi sue vat chit. San trudng thanh kich thich niem mac ong dan mat lam viem 6 ng dan mat. So luong san nhieu gay tac ong mat, mat u lai, tham vao mau, sinh ra hoang dan. San thudng xuyen tiet doc to lam bien doi thanh ong dan mat va mo gan. Doc t6 thAm vao mau gay trung doc toan than. Doc to con pha hoai mau lam Albumin giam, Globulin tang, tang nhiet do co the, tang bach cau. Con vat thilu mau kiet sue, gAy com, doi khi co trieu chung thin kinh (hung phan, di xieu veo). Doc t6 con tac dong lam t6 chuc lien kit tang sinh, thoai hoa nhu mo gan, gay hien tuong xo gan, lam chuc nang cua gan bi pha huy, dan tdi roi loan co nang da day, ruot, thilu mau, gAy dan, suy nhupc. -t # ^ Au trimg di hanh con mang theo nhieu loai vi triing vao gan, mau va nhung co quan khac nen co the lam phat sinh benh truyln nhiem hoac boc mu. 66 San ky sinh d ong mat con hut mau ky chu (moi ngay 1 san lay cua ky chu 0,2 ml mau). Nhu vay, neu so luong san la gan nhieu thi luong mau chung chiem doat cua ky chu khong phai la nho. 2.1.6. Trieu chung lam sang Sue vat non thudng phat benh d the cap tinh. Sue vat trudng thanh thi trieu chung khong r5, benh thudng d the man tinh. - The cap tinh: It xay ra. Thudng gap d giai doan san non di hanh trong co the va khi nuoi duong kem. Con vat suy nhupc, kem an, ia chay, chuong bung, mieng hoi, sot, gan sung to va dau, thieu mau, vang da va niem mac, doi khi co trieu chung than kinh (lao dao, di xieu veo), kiet sue. Co the chet do xuat huyet nang, trung doc va suy nhuoc co the. - The man tinh: Pho bien d trau, bo, de, cuu trudng thanh, duoc nuoi duong tot va san da phat trien den giai doan trudng thanh vdi so luong it. Con vat suy nhuoc, an it, niem mac nhot nhat, long xii va de rung. Thuy thung d mi mat, yem, nguc. Nhai lai kem, khat nude, ia chay xen ke tao bon, gay dan. Kiem tra lam sang thay gan sung to va dau. Luong sira co the giam tdi 30 - 50%. Vat co the chet do kiet sue. 2.1.7. Benh tich Tuy muc do nhiem ma benh tich the hien khac nhau. Sue vat nhiem nhieu san f r ng Fasciola Trtmg Param phistom um Mau sic Hinh dgng Te bao noan hoang Vang sam. Hai dau thon nho gan deu nhau. To deu nhau, xep kin vo. Xam nhgt. Mot dau to, mpt dau nho. T$p trung thanh cym, phan bo khong deu, khong xep kin vo. - Chan doan bang khang nguyen: Dung khang nguyen chi tir san trudng thanh hoac au triing tiem noi bi, can cu vao phan ung noi tiem de phat hien benh. Tuy nhien, phuong phap nay chua duoc ap dung rong rai do che khang nguyen phuc tap va co thi xuat hien phan ung cheo vdi khang the cua khang nguyen khac. ft , * Vai sue vat chet: Mo kham tim Fasciola d giai doan trudng thanh va au triing. Phuong phap nay chinh xac hon ca. 68 2.1.9. Dieu tri Thuang dung cac thuoc sau: - Thuoc Dertil: Dertil la thuoc co tac dung dac hieu v o i san la gan Fasciola. Ten khac: Menichlofolan, Bayer ME 3625, Bayer 9015A, Bilevon M. Dertil duoc bao che thanh vien to, mau xanh la cay dam. Vien Dertil “O” co chua 100 mg hoat chat, vien Dertil “B” chua 300 mg hoat chat. Dertil co tac dung diet san la gan truong thanh d gia sue nhai lai. Voi lieu cao con diet dupe ca san non dang di hanh trong nhu mo gan. Thuoc chi can dung mot lan, khong can dieu tri lap lai. Dupe chi dinh dieu tri benh san la gan cap tinh va man tinh cho gia sue nhai lai. Lieu luong: Bo: 5 - 6 mg/kg TT Trau: 8 - 9 mg/kg TT De, cuu: 5 - 8 mg/kg TT (the man tinh: 5 - 6 mg/kg TT, the cap tinh: 7 - 8 mg/kg TT). f r f f m t Cho tung ca the uong thuoc, hoac goi thuoc vao la chuoi non, dua sau vao mieng cho con vat nuot. - Thuoc Fasciolid (ten khac: Fasciolidum) Thuoc dupe bao che duoi dang dung dich mau vang nau, chua 25% hoat chat Nitroxynil. Fasciolid co tac dung tay san la gan Fasciola dang truong thanh va cac giun tron duong tieu hoa loai nhai lai, dupe chi dinh tay san la gan cho gia sue nhai lai. LiSu luong: 0,04 ml/kg TT (1 ml/25 kg TT, tuong duong 1 mg hoat chat/kg TT). Tiem duoi da. De tay san la gan, nen dung thuoc 2 - 3 lan, cach nhau 25 - 30 ngay. - Thuoc Tolzan - F (che pham cua Oxyclozanid), dupe bao che duoi dang dung dich hoac vien nen, dung voi lieu 10-11 mg/kg TT. Thuoc co tac dung dac hieu vai san Fasciola truong thanh va san non d trau, bo, de, ciru. Hien nay, tren thj truong thuoc thu y thay pho bien thuoc Tolzan - F dang vien nen, cho uong tay san Fasciola voi lieu 1 vien (1000 mg/90 - 100 kg TT). Tolzan - F da dupe su dung cho trau, bo d nude ta, song chua co ket qua nghien cuu thu nghiem tay san la gan cho de, vi vay can thu nghiem trudc khi dung dai tra. - Thuoc Fasinex (che pham cua Triclabendazole): Thuoc co tac dung diet ca san non va san trudng thanh ky sinh d ong dan mat hoac dang di hanh trong cac nhu mo gan. Fasinex dupe chi dinh dung dieu tri benh san la gan cho sue vat nhai lai. Lieu luong: 10-12 mg/kg TT. Cho uong mot lan duy nhat. f # f Thuoc co hieu lire cao va an toan cho gia sue dung thuoc. 69 Ngoai cac thuoc tren, Albendazole, Bithionol, ClosateL. cung co tac dung tay san la Fasciola d sue vat nhai lai. Luong To Thu va cs (1997) da danh gia ve cac thuoc tri san la gan va ket qua thir nghiem d trau, bo Viet Nam. Tac gia khuyen cao rang, tren thi trudng Viet Nam hien nay nen sir dung Fasinex - 900 dang vien (1 vien/75 - 100 kg TT) hoac Fasinex - 900 dang sira (10 m l/100 kg TT), cho hieu luc cao. Sir dung Fasinex lieu 12 mg/kg TT tay san la gan cho trau, Phan Luc va Tran Ngoc Thang (1999) cho biet, thuoc co hieu luc va hieu lire tay sach san deu dat 100%. Nguyen Thj Kim Lan va cs (2000) da thir nghiem mot s6 thuoc tay san la gan cho de dia phuong d tinh Thai Nguyen va Bac Kan, ket qua thay: Thuoc Dertil (lieu 5 - 8 mg/kg TT) co tac dung tay sach 100% va an toan doi vdi de; thuoc Fasciolid (lieu 0,04 ml/kg TT) co hieu luc tay sach la 95% va tuong doi an toan cho de; thudc Vermitan (chua 20% Albendazole, lieu 35 mg/kg TT) dat hieu luc tay sach va an toan deu la 100%, ngoai ra Vermitan con co tac dung tay ca san day va giun tron d de. 2.1.10. Phong benh - Dinh ky tay san la gan cho sue vat nhai lai it nhat 2 lan 1 nam vao miia xuan va cuoi thu. 7 » - U phan theo phuong phap nhiet sinh hoc de diet trung san. - Xir ly co quan co san. Neu gan co nhieu san phai huy bo hoac che bien chin lam thuc an gia sue. - Diet ky chu trung gian: Thao can nude, lam kho d6 ng co, bai chan. Co thi dung voi bot, dung dich sunfat dong... de diet 6 c; nuoi thuy cim dl an oc. - Ve sinh thuc an, nude uong de tranh sue vat nu6 t phai Adolescaria. - Khong nhap sue vat tir noi co benh khi chua duoc kilm tra va dieu tri triet dl. 2.2. Bfnh san la ruot Ion (Fasciolopsiasis) Benh san la ruot lorn do loai san la Fasciolopsis buski gay ra. Benh ph6 biln d Mu het cac nude d khu vuc chau A va Dong Nam chau A. San la F. buski dupe bac sy Busk phat hien nam 1783 d ta trang cua ngudi. Tir do din nay, co nhilu nha khoa hpc tap trung nghien ciru: Lankester (1957), Cobbol (1859), Looss (1899), Nakagawa (1921), Barlow (1925), Hira Bing Nhu (1964), Tr&n Tam Dao (1965), Muttalib (1975), Idris (1980), Li (1981), Grazick (2000)... Tac hai cua san lam cho lpn sinh trudng cham, tham chi sut can. Ngoai lpn, ngudi va mot so dong vat khac cung nhiem va bi benh. 2.2.1. Can benh, ky chii va vi tri ky sinh - Can benh: Benh do san la Fasciolopsis buski gay nen. San ky sinh d ruot non. 70 - Ky chu: Lgn, doi khi thay ca d ngudi, cho, meo. - Ky chu trung gian la nhung oc nude nggt: Planorbis coenosus, Segmentina calathus, Hippeulis cantori... Theo Phan Luc (1976), Nguyen Thi Le (1986), d Viet Nam, oc Planorbis hemisphaerula, Gyraul sinensis, Gyraul heudei la ky chu trung gian cua san la ruot. 2.2.2. Dac diem hinh thai can b$nh F. buski co hinh la, mau do hong (con goi la san tai hong), phinh rong phia sau, thon nho ve phia dau. San dai 20 - 70 mm, rong 8 - 20 mm, dai 0,5 - 3 mm. Co hai giac bam rat gan nhau d phia trudc co the, giac bung ldn hon giac mieng. Thuc quan ngan, hau nho. Manh trang phan thanh hai nhanh ngoan ngoeo d hai ben than va keo dai ve phia cuoi than. Hai tinh hoan phan nhanh nhieu, xep tren dudi d phan sau than san. Buong trung phan nhanh d phia trudc tinh hoan va hoi lech sang trai. Lo sinh san d phia trudc giac bung. Tuyen noan hoang phan nhanh hinh canh cay d hai ben than san. Trung mau vang chanh, vo mong, phinh rong d giua than, thon dan ve phia hai dau, d dau nho hon co nap trung. Trung dai 0,13 - 0,14 mm, rong 0,08 - 0,085 mm, phoi bao phan bo deu va xep kin vo trung. GiAc mi?ng Manh triing _ Gidc bung Tit cung Buongtrim g L§ sinh dye Tuyen noan ho&ng Tinh hoan Hinh 24. So do san F. buski Hinh 25. San F. buski nhuom carmin Hinh 26. Trimg F. buski (10 x 20) Hinh 27. San F. buski tuoi thu thap tu lorn mo kham 71 2.2.3. Vdng dai San truong thanh ky sinh d ruot non Ion. Sau khi thu tinh, san de trung, trung theo phan ra ngoai (moi san de 15.000 - 18.000 trumg/ngay). Gap dieu kien thich hop (t° = 25 - 35°C, pH= 6 - 7, co anh sang, co nuoc...), sau 2 - 3 tuan, trung phat trien thanh ? r f Miracidium, thoat khoi vo trung va bai trong nuoc (co the song 6 - 8 gia). Neu gap ky chu trung gian, Miracidium chui vao, rung duoi va bien thanh Sporocyst. Sporocyst sinh san vo tinh cho ra Redia. Redia lai sinh san vo tinh cho ra nhieu Cercaria (thoi gian tu khi Miracidium vao ky chu trung gian den khi thanh Cercaria la 30 - 50 ngay). Ra khoi ky chu trung gian, Cercaria bai tu do trong nuoc roi bam vao cay co thuy sinh, rung duoi, tao vo quanh minh va bien thanh Adolescaria. Neu Ion, ngudi nuot phai Adolescaria, vao ruot, vo ngoai phan huy, au trung dupe giai phong va phat trien thanh san trudng thanh sau 3 thang. San trudng thanh co the song d lgn 2 nam, d ngudi 4 - 5 nam. Chu ky sinh hoc (vong ddi) cua F. buski dupe mo phong theo so do sau: \ » IV So do bieu dien chu ky sinh hoc cua san la Fascilopsis buski Hinh 28. Vong doi san la ruot Ion Fasciolopsis buski 1. Trung 2. Trung c6 M iracidium 3. M iracidium thoat khoi vo 4. Cac dang au triing trong KCTG 5. C ercaria 6. Adolescaria 7. San truong thanh d ruot non ngudi va lgn 8. San trudng thanh de trung, trung theo phan ra ngoai. 72 2.2.4. D[ch te hpc - Nguon gieo rac can benh la nhung Ion va ngudi mang san. San trudng thanh hang nam thai ra ngoai canh mot luong trung rat ldn. Nhung vung lay loi, am thap la nhung noi mam benh ton tai va phat trien. - Benh phan bo rong khap cac vung, nhung vung dong bang Ion mac nhieu nhat (53,6%, co noi 100%), roi den vung trung du (38,1%, co noi 80%), thap hon d vung nui (8,3%, co noi tdi 50%). - Tap quan chan nuoi anh hudng ro ret den benh san la ruot Ion. Nuoi Ion bang rau song lay tir nude len hoac tha rong thi Ion mac nhieu va nang. Lon nhiem Fasciolopsis buski do an song cac loai thuc vat nude nhu rau muong, rau lap, rong, beo...; ngudi nhiem san la ruot, ngoai viec an song rau muong, con do an song cu meng, ngo sen va cu au (Nguyen Van Tho, 2002). - Tuoi Ion cang cao thi ty le nhiem san cang cao va cudng do nhiem cang nang. - Lon mac benh d ca 4 miia, nhung nhiem nhieu nhat la vu He - Thu (thang 5-11). - Sue de khang cua trung san va Adolescaria khong cao. Trung bi diet nhanh trong ho u phan vao miia he va cham hon vao miia dong, khi nhiet do dat den 50 - 54°C. Trung bi diet khi qua he thong u men sinh khi gas trong 20 - 30 ngay (Shinobu Yoshihara va cs, 1998; Nguyen Van Tho, 2003). 2.2.5. Ca che sinh benh - Tac dong ca giai: San trudng thanh co giac bam khoe, lam ruot bi viem, loet. So luong san nhieu co the lam tac ruot. - Tac dong dau doc: Doc to cua san lam Ion gay com, thuy thiing, sut can, thieu mau, bach cau tang, sue de khang giam. - Tac dong chiem doat dinh duong: San F. buski lay duong chap d ruot non, lam cho Ion suy dinh duong, thieu mau. 2.2.6. Trieu chung lam sang Lon bi benh an uong that thudng, Ion gay com, thuy thung, ia chay, long xu, cham ldn. Theo Pham Van Khue va cs (1996), trung binh 1 san lam giam 1,86 - 2,57 gam thit trong 1 ngay. Phan Trong Cung (1991) nhan xet, trong 35 ngay Ion bi benh, trung binh 1 san F. buski lam Ion giam 65 gam khoi luong. ? ' y f i Mo kham lpn bi benh san la ruot Ion thay thanh ruot non day len, co nhieu bien doi hoai tu tren niem mac ruot, co rat nhieu san F. buski ky sinh d ruot non. 2.2.7. Chan doan benh r y y y - Voi sue vat con song: Xet nghiem phan bang phuong phap doi rira nhieu lan tim trung F. buski. Ngoai ra co the lam phuong phap chan doan mien dich: Tiem khang nguyen vao noi bi, can cu vao phan ung noi tiem de phat hien benh (hien nay phuong phap nay chua duoc dung rong rai). - Voi sue vat chet: Mo kham tim F. buski d ruot non va kiem tra benh tich. 73 2.2.8. Dieu tri De sir dung thuoc tAy F. buski cho Ion va ngudi co hieu qua, can xay dung lich tay trir thich hop vdi dieu kien cu the d viing co benh. y f 0 Viet Nam, cac tac gia da xac dinh rang, Dipterex va Dichlovos la nhung thuoc tAy co hieu qua cao vdi san F. buski. Cac thu6 c nay da duoc dung d nude ta trong nhieu thap ky. Tuy nhien, nude ta da cam sir dung Dipterex va Dichlovos tay giun san cho gia sue. Tir nam 2002 din 2005, chung ta chua xac dinh duoc thuoc co tac dung tAy san la ruot Ion co hieu qua. Nguyen Van Tho (2005) da bao cao ket qua nghien cuu sir dung thuoc Praziquantel lieu 15 mg/kg TT tay san la ruot Ion dat hieu luc 93,73%; ty le sach san dat 90%, thuoc co tac dung vdi ca san non va san trudng thanh, dong thoi an toan vdi Ion. Tac gia cung cho biet, thuoc Triclabendazole co hieu luc thap vdi san F. buski (chi dat 36,84%; ty le sach san la 1 0%). Tinh hinh sir dung thudc tay F. buski d trong nude va nude ngoai duoc liet ke d bang sau: Bang. Cac thudc da dirffc dung de tay F. buski & lpn va nguoi Logi thuocLieu dungNude sue dyng Nguon tai lieu Lon Ngudi Tetraclorua - cacbon (CCU) Hgt cau 0,1 -0,15 g/kg TT - Vi#t Nam Trjnh V3n Thjnh (1963) (Areca catechu) - 1 g/kg TT Trung Quoc Barlow, C. H (1925) Hgt thun mun (Embeliarilies) 5 g/lo’n - Vi$t Nam Do Ducrng Thai (1967) Dichlovos (*) 0,2 g/kg TT - Viet Nam Phgm Chuc (1978) Dipterex (*) 0,15-0,2 g/kg TT - Vi$t Nam Phan Lyc (1993) Oxychlosamid 160 mg/kg TT - Bangladesh Muttalib (1975) Praziquantel15 mg/kg TT Thai Lan Bunnag (1983) Lee (1989) 15 mg/kg TT Viet Nam Nguyen Van Tho (2005) r \ r Ghi chu: (-): Khong thay de cap den r f (*): Thuoc da cam su dung tu nam 2002. 2.3. Benh san la da co (Paramphistomatidosis) Benh san la da co do nhieu loai san la ky sinh d da co gay ra. San la da co ky sinh va gay tac hai cho gia sue nhai lai. Benh san la da co hien nay dupe chu y bdi vai tro gay benh nghiem trong cua san non va ty le chet cao d gia sue bi benh. 74 Theo Luong To Thu va cs (1997), kiem tra trau, bo duoi 6 thang tuoi chua thay san la da co, ty le nhiem 6 6-12 thang la 53,05%, 13-18 thang la 100%; 19-36 thang la 88,9%, tren 36 thang la 92,3%. 2.3.1. Can b$nh, ky chii va v/ tri ky sinh - Can benh: Benh do nhieu loai san la thuoc cac giong trong ho Paramphistomatidae gay ra. Trong do loai dupe nghien cuu nhieu la Paramphistomum cervi. - Ky chu: Trau, bo, de, cuu va nhung dong vat nhai lai khac. Ky chu trung gian: Cac loai oc nuoc ngot nhu Planorbis compressa, P. Planorbis, P. contortus, Bulinus contortus... Theo Phan Luc va cs (1999), ky chu trung gian cua san la da co d mot so tinh mien Bac Viet Nam la 3 loai oc nuoc ngot: Bithynia fuchsiana, Gyraulas convexiusculus va Polypylis hemisphaerula. - Vi tri ky sinh: San trudng thanh ky sinh d da co. Thoi ky di hanh thay san non d nhieu khi quan: Da to ong, da la sach, da mui khe, ruot non, ruot gia, ong mat, tui mat, xoang bung, co khi d ca be than cua sue vat nhai lai. 2.3.2. Dac diem hinh thai can benh Paramphistomum cervi co hinh khoi chop, dai 5 - 12 mm, mau hong nhat. Co hai giac bam, giac mieng d dau, giac bung d cuoi than san va ldn hon giac mieng. Lo mieng d day giac mieng. Hau phat trien, thuc quan ngan. Hai manh trang uon cong khong phan nhanh d hai ben than va keo dai den cuoi than. Lo sinh san d dudi cho ruot phan nhanh. Hai tinh hoan hinh khoi phan thuy xep tren dudi nhau d phan sau than san. Buong trung hinh khoi tron d giua tinh hoan va giac bung. Tuyen noan hoang hinh chum nho phan bo tir sau giac mieng den giac bung d hai ben than san. Trung P. cervi mau tro nhat, hinh trung, dau nho hon co nap trung, trung dai 0,11 - 0,16 mm, rong 0,069 - 0,082 mm. K. Paramphistomum B. Miracidium thoat vo 1. NiSp trimg 2.V 6 trung 3. Miracidium Hinh 29. So do san P. cervi Hinh 30. Tieu ban san P. cervi nhuom carmin 75 Hinh 31. San Paramphisromum cervi Hinh 32. Trung Paramphisromum spp. 2.3.3. Vdng dai San trudng thanh ky sinh d da co. Sau khi thu tinh san de trung. Trung theo phan ra ngoai. Gap dieu kien thuan loi thi sau 11-12 ngay, trong trung hinh thanh Miracidium, au trung nay thoat khoi vo trung va bai trong nude tim ky chu trung gian. Gap ky chu trung gian, Miracidium chui vao co the ky chu trung gian va phat trien thanh Sporocyst. Moi Sporocyst sinh san vo ti'nh cho ra 9 Redia, moi Redia sinh san vo tinh tao ra 20 Cercaria. Tir mot Miracidium, sau 52 - 60 ngay phat trien trong co the oc co the sinh ra 180 Cercaria. Cercaria ra khoi ky chu trung gian, bai trong nude mot thai gian va bien thanh Adolescaria la lung trong nude hoac bam vao cay co thuy sinh. Adolescaria co the ton tai kha lau d ngoai canh. Trong dieu kien nhiet do 4 - 8 °C, Adolescaria van ton tai duoc 2 - 3 thang. Neu sue vat nuot phai Adolescaria thi trong ruot, au trung dupe giai phong, di hanh rat phuc tap den da co va phat trien thanh san la trudng thanh. Thai gian hoan thanh vong ddi trong co the sue vat nhai lai la 3 - 4 thang. Hinh 33. Cac dang du trung cua san Paramphistomum spp. 1. Redia va Sporocyst 2. Cercaria 3. A ldolescaria 76 2.3.4. Cor che sinh benh - Vai tro chiem doat chat dinh duong cua san trudng thanh thudng khong ro ret, song vai tro gay benh dac biet nghiem trong cua san non da duoc de cap trong thoi gian gan day. - Au trung di hanh cung gay ton thuong niem mac ruot va cac khi quan khac. Dong thoi, au trung con mang theo vi trung gay benh xam nhap sau vao cac khi quan, lam benh tro nen tram trong hon, co khi lam con vat chet. - San trudng thanh dung giac bung va giac mieng bam chat vao niem mac da co lam ton thuong niem mac. - Doc to cua san gay sung, loet, xuat huyet, tham nhiem te bao, viem tung dam, u dong mat, thuy thung, thieu mau. 2.3.5. Trieu chung lam sang Sau khi xam nhap vao co the, au trung tiep tuc di hanh va cu tru trong cac khi quan lam sue vat met moi, an kem. Theo Lois (1995), sau khi nhiem au trung 2 - 3 tuan, san non di hanh den ruot non, gay kich thich nghiem trong d ruot non lam con vat ia chay, dau bung, ty le chet d giai doan nay tdi 27,4%. Niem mac nhpt nhat, mui loet. Than nhiet binh thudng. Sau 7-10 ngay nhiem, than nhiet co the tang tdi 40 - 40,5°C. Thuy thung d vung thap. Khi sue vat ia chay nang thi phan lan mau va chat nhay, mui thoi. Da co liet, khong o hoi, ngung nhai lai. Con vat dau bung, nghien rang. Khi nhiem nang, con vat gay yeu tram trong roi chet. Neu nuoi duong tot, cam nhiem nhe thi sau 3 - 4 tuan trieu chung mat dan, benh chuyen sang the man tinh. Hinh 34. Trau bi benh san la da co Hinh 35. Bd bi benh san la da co 2.3.6. Benh tich Xac chet gay com, niem mac nhot nhat, co nhung vet loet nong d moi, mui. Da co co nhieu san. Niem mac da co, da mui khe, ta trang va ruot viem cata hoac xu&t huyet, 77 trong dich ri viem co nhieu san non. 6 vach ruot co sir tham nhiem tl bao (chu yeu 1£ bach cau ai toan), xuat huyet va co nhirng biln d6 i hoai tur. 6 the man tinh, niem mac da co bi thoai hoa. Tui mat to ra, dich mat mau vang nhat, trong dich mat thudng co san. Hinh 36. San la da co bam day dac tren niem mac da co 2.3.7. Chan doan r r ' - Vai sue vat song: Dua vao trieu chung lam sang ket hop xet nghiem phan bang phuong phap gan rua sa lang tim trung san (chu y phan biet trung Paramphistomum vdi trung Fasciola). - Vai sue vat: Mo kham tim san trudng thanh d da co va san non d cac khi quan cua co the, dong thoi dua vao benh tich de ket luan. 2.3.8. Dieu tri Nguyen tac chung trong dieu tri benh san la la tim ra nhung loai thuoc mdi, co kha nang tay nhieu loai san la cung mot luc, dong thoi tac dung ca vdi san non va san trudng thanh, han che duoc kha nang khang thuoc cua chung. Cac hoa dupe da dupe su dung diy san la da co gom: - Oxyclozanide: Lieu 10-15 mg/kg TT, cho uong. Oxyclozanide la mot trong so it cac thuoc co hieu lire vdi san la da co non va rat tot cho tay san la gan. Rolfe va Boray (1993) khi su dung ket hop Oxyclozanide lieu 18,7 mg/kg TT va Levamisole lieu 0,4 mg/kg TT da lam giam so luong san la d da co 56,5 - 98,1%, d da mui khe 50 - 92,2% va d ruot non la 61 - 96,1%. Ap dung hai lilu dilu tri each nhau 3 ngay, cac tac gia cho biet: Ty le hieu lire dat 99 - 100%. - Hexachlorophene: Lieu 20 mg/kg TT, cho u6 ng mot lieu don cung co tac dung tay san la da co, song co the co phan ung phu d he M n kinh (Rolfe va Boray, 1993). 78 - Niclosamide: Lieu 160 mg/kg TT, dung 1 lan hoac 2 lan, cach nhau 3 ngay, dat hieu luc kha cao. Thuoc khong co bieu hien doc 6 gia sue duoc dung thuoc (Rolfe va Boray, 1993). - Benzimidazole: Lieu 10 mg/kg TT, cho uong. Thuoc co tac dung tot trong tay san la da co. C) Viet Nam, Luong To Thu va cs (1999), da nghien cuu so sanh hieu lire cua cac thuoc tay san la da co va cho biet, thuoc Okazan (Oxyclozanide) lieu 10 mg/kg TT co tac dung tay san la da co nhung ty le sach san chi dat 30,23%. Khi ket hop thuoc Okazan lieu 10 mg/kg TT voi Levamisole lieu 7,5 mg/kg TT thi hieu lire sach san tang den 62,5%. Thuoc Fasinex lieu 10 mg/kg TT hoan toan khong co tac dung tay san la da co. Thuoc Closantel va Vermitan co hieu lire tay san la da co rat thap (23 - 28,57%). Phan Luc va cs (1999) da so sanh hieu lire cua thuoc Dovenix va Okazan thay, dung Dovenix lieu 10 mg/kg TT dat hieu lire tay san la gan cho bo la 100%, nhung khong tay duoc san la da co. Okazan lieu 12,5 mg/kg TT co hieu lire tay sach san la gan la 92,6% nhung tay sach san la da co chi dat 35,71%. \ f r r > Tran Ngoc Thang (2004) da bao cao ket qua thu nghiem thuoc Benzimidazole lieu 10 mg/kg TT tay san la da co cho trau, bo, hieu luc tay sach dat 92,3% 6 trau va 96,9% o bo. Cung theo tac gia, su dung hon hop thuoc Okazan (lieu 15 mg/kg TT) va Levamisole (lieu 8 mg/kg TT) co hieu luc tay sach san la da co la 79,3% o trau va 78,1% a bo. 2.3.9. Phong benh Cac bien phap phong benh Paramphistomatidosis tuong tu nhu phong Fasciolosis. 2.4. Benh san la tuyen tuy (Eurytremosis) Benh do cac loai Eurytrema thuoc ho Dicrocoeliidae Odhner, 1911 gay ra. Trong t / • T V • / / do pho bien la loai Eurytrema pacreaticum. San ky sinh lam cho ong tuyen tuy day len t t r ^ r v > f va cung lai. Benh pho bien 6 chau A. O Viet Nam, benh co 6 ca ba mien Bac, Trung, Nam. Theo Nguyen Quoc Doanh va cs (2007), ty le nhiem Eurytrema spp. cua bo thit nhap tu Trung Quoc vao nuoc ta la 11,92%. Jefferson R. va cs (2004) cho bi£t: Gia sue nhai lai 6 phia Bac Parana nhiem Eurytrema spp. la 12,53%. 2.4.1. Can benh, ky chu va vi tri ky sinh - Can benh: Benh do san la Eurytrema pacreaticum gay nen. - Ky chu: Trau, bo, de, cuu, cac dong vat nhai lai khac va ca 6 nguoi. Ky chu trung gian: Cac oc can nhu Eulota lautzi, Bradybaena similaris, B. Phacozona. - Vi tri ky sinh: San ky sinh o ong tuyen tuy, co khi thay 6 gan, da mui khe. 79 2.4.2. Dac diem hinh thai can benh Eurytrema pacreaticum co hinh la, mau do sang. PhAn cuoi than nho ra giong hinh cai luoi. San dai 13,5 - 18,5 mm, rong 5,5 - 8,5 mm. Thuc quan ngAn. Hai manh trang hinh ong xep doc hai ben than. Tinh hoan hinh bau due, co khi phan thuy, nAm hai ben mep sau cua giac bung. Tui sinh due hinh bau due dai, nam giua cho phan nhanh cua ruot va giac bung. Buong trung rat nho, 6 sau giac bung. Tu cung xep kin phan sau than san. TuySn noan hoang hinh chum 6 hai ben than va xep sau tinh hoan. Trung mau nau nhat, khong doi xurng. CJ trung gia ben trong da hinh thanh Miracidium. Trung dai 0,045 - 0,052 mm, rong 0,029 - 0,033 mm. Hinh 37. San la Eurytrema pancreaticum Hinh 38. Trimg cua Eurytrema pancreaticum 2.4.3. Vong dai San truong thanh ky sinh 6 ong dan tuy. Sau khi thu tinh, san de trung. Trung theo phan ra ngoai da hinh thanh Miracidium ben trong ton tai dupe vai gio 6 ngoai canh. Neu duoc ky chu trung gian la cac loai oc can nuot thi Miracidium thoat khoi vo trung o trong ong tieu hoa cua ky chu trung gian va chui sau vao gan, tuy cua ky chu trung gian. Sau 4 tuan trong ong tieu hoa cua ky chu trung gian, Miracidium bien thanh Sporocyst I. Sau 97 ngay cam nhiem, Sporocyst I bien thanh Sporocyst II. Sau 165 ngay, Sporocyst II sinh ra 144 - 218 Cercaria. Cercaria ra khoi ky chu trung gian bang duong phoi duoi dang nhirng boc co phu chat nhay. Nhirng boc nay bam tren cay co. Neu sue vat nhai lai an co nuot phai, Cercaria vao ong tieu hoa, qua ong dan tuy xam nhap vao nhirng ong cua tuyen tuy va phat trien thanh san truong thanh. Thoi gian song 6 ky chu khong qua 10 thang. Theo Kaufman J. (1996), neu chau chau nuot Cercaria thi chau chau co vai tro nhu ky chu trung gian bo sung cua san la tuyen tuy. 80 Hinh 39. Vong dai cua Eurytrema pancreaticum 1. San de trung c6 Miracidium 2. Oc can nuot trung 3. Chau chdu nu6t Cercaria tir oc can thai ra 4. Trau, b6 nuot chau chau co Cercaria 5. Trau, b6 Sn phai Cercaria do oc can thai ra sS nhilm san 2.4.4. Cache sinh benh Tac dong co gioi cua san gay ra nhung bien doi nghiem trong ve cau true va chuc r r r nang tuyen tuy. San trudng thanh kich thich lam ong tuyen tuy bi viem, niem mac day len, to chuc lien ket va co ong tuyen tuy phat trien. Khi au trung chui sau vao cac ong dan nho roi phat trien thanh san truong thanh, gay tac va viem cac ong dan. Bien doi benh ly con thay 6 to chuc tuy va cac dao Langerhan. Khi ong dan bi tac, dich tuy chay ra kho, thuong ri qua thanh ong lam rach vo tuyen. Tuyen co nhung bien doi hoai tu do qua trinh thoai hoa, do ong tuy bi viem lam to chuc ben canh bj teo. Nhung bien doi benh ly o tat ca cac bo phan cua tuyen gay nen nhung roi loan qua trinh dong hoa chdt dam, duong va mo. Cong nang tuyen tuy bi roi loan lam con vat dinh duong kem, thieu mau, gay yeu. 2.4.5. Dac diem dich te Theo Dang Van Ngu (1942), 50% so bo 6 lo mo Ha Noi nhiem san la tuyln tuy. San la Eurytrema spp. ky sinh 6 gia sue nhai lai nho nho hon khi ky sinh 6 gia sue nhai lai Ion. Trau bj nhiem san la tuyen tuy voi ty le cao hon bo. Nguyen Quoc Doanh va cs (2007) cho biet: Ty le nhiem trong vu Dong - Xuan la 12,26%, vu He - Thu la 10,85%. Gia sue tuoi cang cao thi ty le va cuong do nhiem cang nang. 81