Giáo trình ký sinh trùng học thú y (giáo trình dành cho bậc cao học) phần 2

Vi tri ciia san la Fasciola trong he thong phan loai dong vat hoc Theo Skrjabin va cs 1977, Nguydn Thi Le va cs 1996, san la gan ky sinh va gay benh cho gia sue nhai lai dugc xep trong h

Chitcmg 7

M 0 T SO CHUYfcN DE BENH GIUN SAN 6 GIA SUC

BENH SAN LA GAN 6 TRAU, BO, DE

(Fasciolosis)

Benh san la gan d trau, bo, de do hai loai san la ky sinh d ong dan mat va gan gay ra

{Fasciola hepatica va Fasciola gigantica) Ngoai trau, bo, de, hai loai san nay con gay benh cho cac dong vat nhai lai khac, doi khi thay ca d ngudi.

F hepatica va F giantica la hai loai san la ph6 bien d cac vung thuoc chau A va Chau Phi Theo Stemphenson (1947) va Urquhat (1956), tac hai cua san la gan doi vdi gia sue nhai lai rat Ion, bidu hien r5 nhat la gay thieu mau, viem va xo gan khi gia sue bi nhidm san la gan d muc do nang.

1 DAC DIEM SINH HOC CUA SAN LA FASCIOLA

1.1 Vi tri ciia san la Fasciola trong he thong phan loai dong vat hoc

Theo Skrjabin va cs (1977), Nguydn Thi Le va cs (1996), san la gan ky sinh va gay benh cho gia sue nhai lai dugc xep trong he thong phan loai dong vat nhu sau:

Nganh Plathelminthes Schneider, 1873

Phan nganh Platodes Leuckart, 1854

Lop Trematoda Rudolphi, 1808

Phan lop Prosostomadidea Skrjabin va Guschanskaja, 1962

Bo Fasciolida Skrjabin et Schulz, 1937 Phan bo Fasciolata Skrjabin et Schulz, 1937

Ho Fasciolidae Railliet, 1895 Phan ho Fasciolinae Stiles et Hassall, 1898 Giong Fasciola Linnaeus, 1758

Loai Fasciola hepatica (Linnaeus, 1758) Loai Fasciola gigantica (Cobbold, 1885)

1.2 Dac diem hinh thai cua san la Fasciola

Cung nhu nhieu loai san la khac, san la gan luong ti'nh, co the thu tinh cheo hoac tu thu tinh San co giac mieng va giac bung, giac bung khong noi voi co quan tidu hoa San khong co he ho hap, tuan hoan va co quan thi giac (d giai doan mao au co dau vet sSc to mat) He sinh due rat phat trien voi ca bo phan sinh due due va cai trong cung mot san

Tu cung san chua day trung.

Co thd phan biet hai loai san la gan thuoc giong Fasciola nhu sau:

co hoac nhin khong ro ret, nhanh ruot chia toa ra nhieu nhanh ngang.

F gigantica (nghla la san la “khong lo”) dai 25 - 75 mm, rdng 3 - 1 2 mm, u 16i hinh

non cua d£u la phzin tiep theo cua than, vi vay no khdng c6 “vai” nhu loai khac cua

gidng Fasciola Hai ria ben than san song song vdi nhau, d£u cudi cua than tu Giic

bung tron ldi ra Rudt, tuyen noan hoang, buong trung va tinh hoan ddu phan nhanh Trung hinh bau due, mau vang nau, phdi bao to ddu va xep km vo Kfch thudc trung:0,125 - 0,170 x 0,06 - 0,10 mm

- F hepatica (Linnaeus, 1758): trai vdi loai trfen, loai nay than rdng, dau ldi va nhd

ra phia trudc lam cho san co “vai”, nhanh ruot chia it nhanh ngang hon

F hepatica (nghla la san la d gan) dai 18 - 51 mm, rdng 4 - 1 3 mm, phin trudc than

nhd ra, tao cho san co vai be ra hai ben Hai ria ben than san khdng song song vdi nhau

ma phinh ra d chd vai roi thot lai d doan cudi than Nhiing dng dan tuyen noan hoang chay ngang, chia vung giua cua san thanh phan trudc va ph£n sau than Ph£n sau than co tinh hoan va bo phan sinh due due Tinh hoan phan nhidu nhanh xep phia sau than Tu cung d phctn giua than trudc tao nen mot mang ludi rd'i nhu to vo Budng trung phan nhanh nam d sau tu cung

Trumg san cd hinh thai, mau sac tucmg tu trung cua loai F gigantica, kich thudc

1.3 Chu ky sinh hoc cua san la Fasciola

Chu ky sinh hoc cua san la Fasciola da duoc Leukart (1882) nghien curu d Dure va

Thomas (1882) nghidn curu d Anh

Fasciola trucmg thanh ky sinh trong dng dan mat cua trau, bo, de Sau khi thu tinh,

m6i san de hang chuc van trumg Nhung trumg nay cung dich mat vao ruot, sau do theo phan ra ngoai Neu gap didu kien thuan loi: duoc nude mua cud'n troi xuong cac vungnude, ho, ao, sud'i, ruong nude nhiet do 15 - 30°C, pH = 5 - 7,7, co anh sang thfch

hop sau 10 - 25 ngay trumg nd thanh Miracidium boi tir do trong nude Neu thieu anh sang, Miracidium khong co kha nang thoat vo nhung van ton tai den 8 thang trong vo,

Miracidium co hinh tam giac, xung quanh than co long va di chuyen duoc trong nuoc

Khi gap vat chu trung gian thfch hop (oc Lymnaea), Miracidium xam nhap co thd oc va phat trien thanh bao a'u (Sporocyst) Nhung Miracidium khong gap vat chu trung gian thi

runglong, rtfa dan va chet

Bao a'u (Sporocyst) hinh tui, mau sang, duoc bao boc bdi ldp mang mdng, cac te bao

ngon lua hoat dong hinh thanh hau, ong ruot va cac dam phdi Trong 1 oc cd the cd 1 - 2

au trung Khoang 3 - 7 ngay, bao au sinh san vo tfnh cho ra nhidu Redia (loi a'u) Mot

bao a'u sinh ra 5 - 15 ldi a'u

Redia hinh suot chi, ft hoat dong, cd mieng, hau, ruot, hinh tui don gian Cd hai he: Redia the he I va Redia the' he II cung phat tridn trong oc - vat chu trung gian 0 nhiet do

16°C hoac tha'p hon, ldi a'u chi san sinh Redia I va dung phat trien d nhiet do phu hop (20 - 30°C), sau 29 - 35 ngay, ldi au bien thanh vi a'u (Cercaria) Mot Redia cd the sinh

ra 1 2 -2 0 Cercaria.

Cercaria (vi au) la au trung d pha sdng tu do cua san la gan, cd cau tao than hinh

trdn lech, dudi dai hom than giup vi a'u van chuyen duoc dd dang trong nude Ca'u tao cua

vi a'u gom giac mieng, giac bung, hau, thuc quan va ruot phan thanh hai nhanh

Theo Ginyecisz - Kaija (1960), trong co the Cercaria cdn cd nhung hat Glycogen

cung cap nang lucmg cho hoat dong song ciia au triing, dac biet la cho su van dong khdng ngimg cua dudi Dudi la co quan van dong ciia vi a'u Theo mot sd tac gia, dudi lam nhiem vu thay doi vi tri ciia au triing trong mdi trudng nude Lizz (1922) cho biet, nhd sir hoat dong tfch cuc cua dudi ma vi au tid'p can dd bam vao cac cay thuy sinh, tao

thanh ken (Adolescaria).

Tir khi Miracidium chui vao oc den khi phat trien thanh Cercaria can khoang 50 -

80 ngay Sau khi thanh thuc, Cercaria thoat khoi oc, ra mdi trudng ngoai, boi tu do

trong nude, cd kfch thudc 0,28 - 0,30 mm chieu dai va 0.23 mm chieu rong Sau vai gid

boi trong nude, Cercaria rung dudi, tiet chat nhay xung quanh than, chat nhay gap khdng khf kho rat nhanh Luc nay Cercaria da bien thanh Adolescaria.

Hinh 45 Cdc dang du triing ciia san Fasciola

1a Mao au nc) ra tir trimg san; 1b Bao au 2a Loi au non; 2b Loi au gia co vT au non 3a Loi au me phong ra nhieu loi au con 3b V7 au au triing san la gan chui khoi oc 4a V7 au rung duoi tao thanh ken

4b Ken san la gan

Adolescaria hinh khoi tron, ben trong chura phoi hoat dong Phoi co giac mieng, giac

bung, ruot phan nhanh va tui bai tiet Adolescaria thudng d trong nude hoac bam vao cay cd thuy sinh Neu trau, bd, de nuot phai Adolescaria, vao den da day va ruot ldp vo

ngoai bi phan huy, au trung duoc giai phong va di chuyen den dng mat bang 3 condudng:

- Mot sd a'u trung dung tuyen xuyen chui qua niem mac ruot, vao tmh mach ruot qua tinh mach cua vao gan, xuyen qua nhu mo vao dng mat

- Mot sd a'u trung khac cung dung tuyen xuyen chui qua thanh ruot vao xoang bung, den gan, xuyen qua vd gan vao dng mat

- Mdt sd a'u trung tir ta trang ngugc dong dich mat d6 len ong dan mat.

Sau khi vao ong dan mat, a'u trung ky sinh d do va phat trien thanh san la gan trudng

thanh Theo Skerman (1966), thdi gian hoan thanh vong ddi la 92 - 117 ngay Fasciola

trudng thanh cd the ky sinh trong dng dan mat cua sue vat nhai lai 3 - 5 nam, cd khi tdi

3 Cercaria rdi khoi oc

4 Adolescaria bam tren cay co thuy

sinh

5 Sue vat nhai lai nuot Adolescaria

6 San la gan tri/dng thanh ky sinh trong ong dan mat

Theo Phan Dich Lan (2004), khoa hoc thu y nude ta da nghien cuu thanh cong vdng

ddi cua san la gan Trong dieu kien nhiet do thfch hop (28 - 30°C), cd oc vat chu trung gian (Lymnae swinhoei va Lymnae viridis), cd vat chu cudi cung (trau, bd, de, ciru) thi vdng ddi cua san la gan d nude ta duoc xac dinh vdi cac mure thdi gian sau:

- O ngoai thien nhien: trung san la gan nd thanh mao a'u (Miracidium ) trong khoang

1 4 - 1 6 ngay.

- O trong oc vat chu trung gian:

M ao a'u (Miracidium ) phat trien thanh bao au ( Sporocyst ) can 7 ngay.

Bao a'u (Sporocyst) phat trien thanh ldi a'u (Redia) can 8 - 2 1 ngay.

Ldi a'u (Redia) phat trien thanh vT au (Cercaria ) non can 7 - 1 4 ngay, thanh v! au

trudng thanh can 1 3 - 1 4 ngav.

- 6 ngoai oc vat chu trung gian: vT a'u phat trien thanh ken (Adolescaria) sau 2 gid.

- 0 trau, bd: khi trau bd, be nghe nuot phai Adolescaria, sau 79 - 88 ngay trong dng dan mat cua trau bd da cd san la gan trudng thanh de trung theo phan ra nsoai.

I

Dieu kien nhiet dd va am do cua nuoc ta ra't thuan lpi cho su nhiem va gay benh cua san la gan (ke ca gay nhiem va nhiem tu nhien) C) nhung vung co mam benh ton tai, cu trung binh 3 thang san la gan lai hoan thanh vong ddi trong co the trau, bo, nghla la trong trau bo lai tao ra mot ddi san mdi Con vat trong khi da cd san la gan ky sinh lai tiep tuc nhidm them mam benh mdi, gay tinh trang b6i nhiem san la gan vi vay cudng

do nhifem tang len theo tuoi trau, bd

2 DAC D IEM D IC H T£ H O C BEN H SAN LA FASCIOLA

Benh san la gan pho bien d khap cac chau luc va nhieu nude tren the gidi 0 Viet Nam, benh tha'y d khap cac tinh thanh trong ca nude

Houmeder (1938) da dieu tra va tha'y, trau, bd, de, ciru, thd d mien Bac Viet Nam

deu nhiem san la F gigantica theo ty le thur tu la 64,7%; 23,5%; 37%; 52,94%; 14,28%;

dac biet cd 2 trudng hop ngudi nhidm san

Trinh Van Thinh (1978) cho bie't, trau trudng thanh mac benh san la gan do F

gigantica, ty le nhiem tdi 50 - 70% Theo Phan Dich Lan (1980), mo kham 1043 trau d

Thai Nguyen, sd trau nhiem san la gan la 57%, trong dd cd nhieu gan phai huy bd do sd luong san qua nhieu Ket qua dieu tra d huyen Binh Luc - Nam Ha, ty le nhidm san la gan d trau la 51,2 - 57,5%

Doan Van Phuc (1980) da kiem tra 64 bd tai trai bd sua Ha Noi, tha'y ty le nhidm

san Fasciola la 73,43% Tac gia cdn cho biet, benh san la gan da anh hdng rd ret den

sUc khoe va san luong sua cua dan bd

Nguydn Due Duong (1995) da xet nghiem phan cua 537 huou tai cac trai nuoi huou

d Ha Tinh, Quynh Luu, Didn Chau (Nghe An) va cong vien thu le Ha Noi, phat hien

13,22% sd huou nhidm san F gigantica.

Theo Nguydn Quang Sue va Nguydn The Hung (1995), dan dd Bach Thao sau hon 3 nam nudi tai Trung tam nghidn cuu dd, thd Son Tay va mot sd gia dinh nuoi de nhidm san la gan vdi ty le 30,4%

Doan Van Phuc, Vuong Due Chat, Duong Thanh Ha (1995) cho bie't, trau bd thuoc khu vuc Ha Noi nhidm san la gan ty le 53,41%

Ket qua kiem tra trau, bd d mot sd dia phuong xung quanh Ha Noi, Bac Giang Thai Nguydn, Hoa Binh, ty le nhidm san la gan la 44,53% Trong dd, trau nhidm 33.92% bd nhidm 54,21% (Luong Td Thu va Bui Khanh Linh, 1996)

Nguyen Thi Kim Lan (2000) da nghidn cuu va cho biet, dan dd dia phuons nuoi d cac tinh Thai Nguydn, Bac Kan, Tuyen Quang va Cao Bang nhidm san la gan bien dong tir 5,3% den 27,9% tuy theo dia phuong

Ty le va cudng do nhidm san la gan d gia sue nhai lai phu thuoc vao nhung veu tdsau:

- Yeu td thdi tiet, khi hau va mua vu

Thai tiet, khi hau cua m ot vung, mot khu vuc co lien quan true tiep den su ton tai va phat trien cua oc - vat chu trung gian cua san la gan Dieu kien am udt, mua nhidu tao ra moi truong nude, giup oc nude ngot song va sinh san thuan loi.

Trinh Van Thinh (1963), Trinh Van Thinh va cs (1978), Pham Van Khue va Phan Luc (1996), Nguydn Thi Kim Lan va cs (1999) ddu cho biet, gia sue nhai lai nhidm san la gan thudng tang ldn vao mua vat chu trung gian phat trien Nhung nam mua nhieu, ty le nhidm san la gan tang len so vdi nhirng nam nang rao va kho han Mua vu gan lidn vdi su thay doi thdi tiet khf hau Miia he thu, sd gia sue bi nhidm san la gan tang cao hon cac miia khac trong nam Cudi miia thu va miia dong benh thudng phat ra.

- Yeu td viing va dia hinh

Viing va dia hinh la hai khai niem khac nhau, song cd lidn quan chat che vdi nhau Cac viing khac nhau cd dia hinh khong gidng nhau Dia hinh la yeu td quan trong quyet dinh su khac nhau giua cac vung.

Cac viing khac nhau trdn the gidi ndi chung va d Viet Nam ndi rieng deu thuoc bon loai dia hinh: ven bien, ddng bang, trung du va mien nui.

Hau het cac nha ky sinh triing hoc thong nhat rang, gia sue nhai lai d viing ddng bang nhidm san la gan nhieu nhat, ty le va cudng do nhidm giam dan ddi vdi dan gia sue nhai lai d viing ven bie’n, vung trung du va viing nui Ve nguydn nhan dan den quy luat nay, cac tac gia (Trinh Van Thinh, 1963; Pham Van Khue va cs, 1996; Soulsby, 1982; Kaufmann, 1996 ) deu giai thfch: viing ddng bang cd nhieu hd, ao, kenh, rach, cd dieu kien cho oc - vat chu trung gian sdng va sinh san Cac kieu dia hinh khac thi van dd nay han che hon so vdi ddng bang.

Hinh 47 Dan bd chan thd d bdi chan cd nguy ca nhiem san Fasciola

Phan Dich Lan (1994) da dieu tra 7.359 trau, bd d 26 tinh mien Bac Viet Nam, ket qua thay: trau bd d vung ddng bang nhidm san la gan cao nhat, sau dd den vung trung

du, viing ven bidn va mien nui (binh quan ty le nhidm san d cac viing dieu tra nhu sau: viing ddng bang tir 19,6% den 61,3%, viing trung du tir 16,4% den 50,2%, viing ven bien

tir 13,7% den 39,6%, vung nui tCr 14,7% d£n 44,0%) Theo Nguydn Dang Khai (1996),

ty Id nhidm san la gan 6 trau bo vung ddng bang qua m6 kham la 88%, vung trung du lk77,6%

- Yeu td loai va tudi vat chu cudi cung

Sue vat nhai lai da duoc thuan hoa nhu trau, bo, de, ciru ddu nhidm san la gan

Fasciola Ngoai ra, sue vat hoang da cung nhidm san la nay (hucru, nai, hoang ) Cung

co nhiing trudng hop tho, ngua, Ion nhiem Fasciola, ngay ca ngudi cung co the nhiem san.

6 nude ta, theo Trinh Van Thinh va cs (1978), Pham Van Khue va cs (1996), loai

sue vat nhidm san la Fasciola nhieu nhat la trau (79,6%), bo it hon (36%), dd ft nhat

(20%) So di trau nhidm san la gan nhidu la do dac tfnh ua nude cua chung (thfch an g£n

ch6 co nude, dam tam trong nude va udng nude 6 vung, ao, kenh rach), trong khi dac diem cua bd va dd ft ua nude hon

Theo Nguydn Thi Kim Lan va cs (1998), dd dia phuong 6 Thai Nguydn, Bac Kan, Tuyen Quang va Cao Bang nhidm san la gan d cac lura tu6i la 14,88%, d dd truong thanh

la 22,86% Tac gia nhan xet: khi thieu thufc an, ca dan dd cd th£ loi xuong ruong nude d£

an co sdng dudi nude, do dd dd dang nuot phai ken gay bdnh

Vd mdi lidn quan giua ty le, cudng do nhidm san la gan va tuoi v |t chu, cac tac gia deu thong nhat rang, tuoi sue vat cang cao thi ty le va cudng do nhidm cang tang ldn Mot dieu dd nhan tha'y la, sue vat tuoi cang tang ldn (thdi gian so'ng cang dai) thi su tid'p xuc vdi mdi trudng ngoai canh cang nhieu, co hoi gap va nuot phai nang a'u

(Adolescaria) cang cao Mat khac, san Fasciola truong thanh cd thdi gian ky sinh d sue

vat nhai lai tuong doi dai ( 3 - 5 nam, tham chf tdi 11 nam) Dd chfnh la cd sd khoa hoc

giai thfch cho quy luat nhidm theo tuoi vat chu cua san la Fasciola sp

Phan Dich Lan (1994, 2004) cho bie't, trau dudi 3 nam tuoi chi nhidm san la gan 17,2 - 22,0%; trau 3 - 5 nam tuoi nhidm san la gan 31,2 - 40,2%, trau 5 - 8 nam tuoi nhidm 42,4 - 57,5%, trau trdn 8 nam tuoi nhidm 56,8 - 66,3%, trau o do tuoi phe' canh (loai thai) khi mo kham thay ty le nhidm cao tdi 84,6% (nhung trau nay bi benh ra't nang, gan phai huy bo toan bo do cd qua nhieu san ky sinh) Theo Nguydn Thi Kim Lan (2000), ty le va cudng do nhidm san la gan cung tang ldn theo tuoi dd

Nguon gieo rac benh chu yeu la sue vat nudi (trau, bd, dd, ciru ) va nhung da thu

mang Fasciola Trung san la gan theo phan cua sue vat ra ngoai tu nhidn Hang nam,

mdi san la gan ky sinh de khoang 6000 trung Vi vay, mdi sue vat mang san hang nam thai khoi luong trung kha ldn ra ddng co va cac bai chan tha Nhung dong co am thap, lay loi la nhung noi c£n thiet de mam benh phat trien va xam nhap vao sue vat, dong thdi

thuan loi cho trirng no thanh Miracidium va thuan loi cho vat chu trung gian cua

Fasciola ton tai va phat trien.

- Vat chu trung gian cua Fasciola sp.

Su phan bo cac loai oc - vat chu trung gian cua san la gan phu thuoc vao cac \iing dia ly khac nhau Theo Pham Van Khue va cs (1996), Kaufmann (1996), vat chu trung

gian cua san la Fasciola la cac loai 6'c nude ngot ho Lymnaea: L auricularia, L

swinhoei, L viridis, Galba truncatula, Radix ovata

Phan Dich Lan (1980) da tong hop va cho biet: loai oc - vat chu trung gian cua F

A/

gigantica b An Do la L acuminata, b chau Phi la L natalensis, b Pakistan la L permisca, b Apganixtan la L luteola, b Malaixia la L auricularia, b Nhat Ban la L pervia, b Indonexia va Philippine la L viridis, b Hungari la G truncatula v.v

A/

Oc G truncatula la loai oc nho, dai 10 mm, rong 5 mm, vo mau xam; dau dai, co 4

-5 gai thit Nhiet do tot nhat d£ loai oc nay phat trien la 20 - 22°C, pH: 6,6 - 8,6, sinh san manh tir thang 4 den thang 9

Theo Jorgen Hansen va cs (1994), nhiet do thfch hgp nhat cho su phat trien cua oc la

15 - 26°C, khi b nhiet do nay chung de so lugng trung ra't Ion Trung no trong vong 2

tuan va sau 1 thang thanh oc trudng thanh Mot con 6c trong vong 1 0 - 1 2 tuan co the sinh san ra hang ngan con oc O dudi 10°C, 6c khong phat trien va ngimg hoat dong Tuy nhien, 6c co the chui vao bun va song trong dieu kien ba't lgi nhieu thang

Phan Dich Lan va cs (1985) da khao sat dac diem sinh hoc cua oc - vat chii trung

gian ciia F gigantica b mien Bac Viet Nam Tac gia cho biet, vat chii trung gian ciia san

la Fasciola la hai loai oc nude ngot thuoc giong Lymnae vdi ten goi la oc vanh tai (L

swinhoei) va oc chanh (L viridis) Loai L swinhoei co vo mong, dd vd, khong co nap

mieng, kfch thudc 20 mm, vong xoan cuoi ciing rat ldn, chiem gan het phan than, vo loe

ra nhu vanh tai Loai L viridis cung co vo mong, khong co nap mieng, kfch thudc 10

mm, vd d£ vd, co 4 - 5 vong xoan, vong xoan cuoi cung ldn (hinh 48)

a'Hinh 48 O c k y c h it tr u n g g ia n 1,3 L viridis 2,4 L swinhoei 5 G truncatula

A/ /

Oc L viridis thucmg sdng 0 nhung noi nude xam x2fp, de trimg thanh 6 7 - 1 0 trung,sau 7 ngay no thanh 6c con Oc L swinhoei thucmg s6ng trfti n6i d c6ng ranh, ao, h6, de

trumg quanh nam, m6i 6 co 60 - 150 trung Trong didu kidn nhiet d6 d nude ta, 6c de

quanh nam va quanh nam co 6'c con dupe nd ra

Phan Dich Lan (1994, 2004) cho bidt: 6c L swinhoei phan b6 nhidu hem d vung dong bang, trong khi 6c L viridis phan bo nhidu hom d vung nui, trung du va ven bi&i

Theo ket qua nghien cun cua tac gia thi hai loai 6c nay ddu xua't hidn trong ca 12 thang ciia nam, nhung mat do (tmh tren 1 m2) khac nhau theo vung: viing d6ng bang, mat dd 6c

L swinhoei cao hem va phan bo ddu trong nam, con oc L viridis thi xua't hien vdi mat d6

cao hem d cac viing nui, trung du, ven bien Tir do, tac gia nhan xet rang, L swinhoei

chiu nude hom, con L viridis chiu can hon.

Su t6n tai va phat trien quanh nam, d ta't ca cac vimg cua 6c - vat chu trung gian la didu kien quan trong nhat lam cho ty le nhidm san la gan ciia sue vat nhai lai d nude ta cao va pho bien d tat ca cac viing Phan Djch Lan (1994, 2004) da tong hop va cho biet, nude ta dupe xep vao mot trong 5 nude d chau A trong lua nude cd dan trau, bd nhidm benh san la gan vdi ty le cao nhat Ket qua dieu tra d mot so viing cho tha'y:

6 l l tinh midn nui, ty le nhidm san la gan cua trau bo la 39%

CJ 4 tinh trung du, ty le nhidm san la gan ciia trau bo la 42,2%

O 5 tinh thuoc viing dong bang, ty le nhidm san la gan la 57,5%

O 6 tinh thuoc viing ven bien, ty le nhidm san la gan la 36,7%

Theo Nguydn Trong Kim (1997), giua ty Id nhidm a'u triing san la gan cua 6c - vat chu trung gian vdi ty le nhidm san la gan cua trau, bo co mdi tuong quan thuan, nghla la, ne'u ty le nhidm a'u triing san la gan d 6c nude ngot cao thi ty le nhidm san la gan cua trau, bo d khu vuc do cung cao

- Sure de khang cua trumg va a'u triing san la gan

Trumg san la gan dupe thai theo phan sue vat nhai lai ra m6i trudng ngoai canh Trumg san ra't nhay cam vdi dieu kien kho han va tac dong true tiep ciia anh sang mat trdi O trong phan kho, phoi ngimg phat trie’n, trumg bi chet sau 8 - 9 ngay

Trong dieu kien kho han, vd trung bi nhan nheo, bien doi hinh dang, Miracidium bi

chet trong vo trung sau 1 - 1 ,5 ngay 6 moi trudng 3m udt, trumg cd kha nang song kha lau (trong phan hai am, trung ton tai den 8 thang) Dudi anh nang chi£u true tiep, trumg chet nhanh Phoi bi chet sau 2 ngay d nhiet do thap (-5°C -> - 15°C) Nhiet do 10 - 20° C, trung ngimg phat trien Nhiet do 40 - 50°C, phoi chet sau vai phut (Pham Van Khue va

cs, 1996)

Khi phat trien den giai doan nang au (Adolescaria), sue dd khang ciia chung tang len ro ret Adolescaria co kha nang ton tai d nhiet do -4°C -> -6°C 6 dieu kien nhiet do

binh thuang, nhung Adolescaria co trong co kho bi am va trong moi truang nude co the

t6n tai den tren 5 thang (Kaufmann, 1996)

3 DAC DIEM BENH L t VA LAM SANG BENH SAN LA FASCIO LA

Sue vat bi benh san la gan the hien nhung bien doi ca ban a gan va ong mat do tac

dong cua Fasciola gay ra.

3.1 Benh ly va lam sang benh san la gan d trau, bo

3.1.1 Benh ly cua benh san la gan trau bd

Theo cac nha ky sinh trung hoc, san la gan gay benh a vat chu bang cac tac dong ca hoc, tac dong cua doc to, su chiem doat dinh duang va tac dong mang triing Khi sue vat mai nhidm benh, san non di hanh trong ca the lam ton thuang d ruot, thanh mach mau, nhu mo gan Mot sd au triing co thd theo mau di chuyen “lac ch6” den phdi, lach, ca hoanh, tuyen tuy gay tdn thuang va xua't huye't nang hoac nhe San non xuyen qua cac nhu mo gan, lam to chiic gan bi pha hoai, tao ra nhung dudng di hanh day mau va manh

to chuc gan bi pha huy Gan bj viem til nhe den nang tuy theo sd luong a'u triing nhidm vao ca the Sue vat bi thieu mau do xuat huyet, co the chet do mat mau

Tac dong ca gidi cua san con tiep tuc khi san da vao dng dan mat, tiep tuc tang len

vd kich thudc va phat trien thanh san trudng thanh San trudng thanh thudng xuyen kich thich niem mac dng mat bang cac gai cutin tren ca the, gay viem ong mat So luong san nhieu co the lam tac dng mat, mat u lai khong xuong ruot duoc se tran vao mau, gay hien tuong hoang dan

Trong qua trinh ky sinh, san thudng xuyen tiet doc td Doc td tac dong vao thanh dng mat va mo gan, gay bien doi dai the va vi the, lam tang qua trinh viem Dong thdi, doc td cua san con hap thu vao mau, gay hien tuong trung doc toan than, gay huy hoai mau, lam bien chat protein trong mau, lam Albumin giam, Globulin tang Doc td cua san con lam tang nhiet do ca the, tang bach cau (dac biet la bach cau ai toan) Doc td cua san eon tac dong vao than kinh, lam cho con vat co trieu chung than kinh (run ray,

di xieu veo ) Doc td cua san la gan tac dong vao thanh mach mau, lam tang tinh tham ciia thanh mach, gay hien tuong thuy thung, lam cho mau dac lai Cung do tac dong cua doc td nen giua nhirng tieu thuy gan co hien tuong tham nhidm huyet thanh va te bao, hinh thanh nen cac mo lien ket mdi doc theo cac vach ngan cua tieu thuy gan va quanh dng mat, vi vay nhirng dng mat nay cung day len Qua trinh viem keo dai lam cho cac te bao to churc tang sinh, thay the nhung te bao nhu mo gan gay hien tucmg xa gan va teo gan Khi sue vat nhidm san la gan nang, hien tuong xa gan chiem dien tich ldn ciia gan, lam cho chuc nang ciia gan bi pha huy Tir do dan den hang loat roi loan khac nhu: roi loan ca nang da day - ruot, thieu mau, suy nhugc, gay dan, co chuong, xoang phuc mac tich nude

Mot tac dong quan trong ciia Fasciola khi ky sinh d vat chii la chiem doat dinh

dudng Dinh dudng ciia san la gan la mau sue vat ma no ky sinh Bang phuang phap

phong xa, ngudi ta da tha'y m6i san k f sinh d 6ng dan mat la'y 0,2 ml mau m6i ngky Nhu vay, neu sue vat nhidm ft san thi vai tro chi£m doat dinh ducmg kh6ng ro, nhung neu m6i sue vat co hang tram, hang nghin san ky sinh thi lugng mau mat di rat nhidu ^Ngoai cac tac dong gay benh trdn, trong khi di hanh, san non con mang theo cac loai

vi trung tir ben ngoai vao mau, gan va nhung co quan khac, gay nhumg boc mu hoac gay benh truyen nhidm khac

Ta't ca nhumg tac dong ke trdn cua san la Fasciola lam cho sure dd khang cua co th^

trau, bo giam sut nghiem trong, dd mac cac benh khac, hoac lam cho cac benh dang c6

trong co thd sue vat nang them ldn

Daves (1958) nhan xet rang, gia sue bi suy nhugc va thi£u mau la do doc td' cua F

gigantica, doc to cua san con tac ddng gay hien tucmg protein trong huye't thanh bi£n

chat, luong Albumin giam va Globulin tang Davtjan (1962) da chumg minh, qua trinh di umg cua co the sue vat la ket qua tac dong cua cac khang nguydn sinh ra tir san vdi khang the xua't hien trong to chuc gan, va cac chat sinh ra tir to chirc khac bi huy hoai Qua trinh di umg dan den nhumg roi loan dau tien, bidu hien bang hien tuong suy dinh

duang, thieu vitamin A, bang sir tang qua nhieu bach cau ai toan trong co the’.

3.1.2 Trieu chiing benh san la gan a trau bd

Trieu chung lam sang la bieu hien ra ben ngoai bai cac tac dong gay benh cua san

Fasciola Trieu chung a trau, bo bieu hien nang hay nhe con phu thuoc vao cudng d6

nhidm san, tinh trang sure khoe va tuoi sue vat, tinh trang cham soc quan ly v.v

- The cap tfnh thucmg gap a trau, bo 1,5 - 2 nam tuoi (Pham Van Khue va cs, 1996), trong giai doan san non di hanh hoac khi nuoi duang, cham soc kem

Sue vat bidu hien: an uong sut kem, suy nhugc, chudng bung, ia chay, mieng hdi, sot, gan sung to va dau, thieu mau, vang da, doi khi co trieu chumg than kinh (lao dao, xieu veo) Sue vat co the chet do xuat huye't nang, trung doc va suy nhugc ca the

- The man tfnh thay pho bien a trau, bo truong thanh, khi sue vat dugc nuoi duang tot va san da a giai doan trudng thanh, ky sinh trong dng dan mat vdi so lugng ft Thd man tfnh thudng xuat hien sau the cap tfnh 1 - 2 thang

Sue vat bieu hien: an uong kem, suy nhugc, niem mac nhgt nhat, long xu va dd rung (nhat la long d vung doc hai ben sudn va doc xuong tic) Xuat hien thuy thung d mf mat, yem, nguc, bo phan sinh due Thuy thung ban dau luc thay, luc khdng, vd sau thay lidn tuc Con vat nhai lai yeu, khat nude, ia chay xen ke tao bon, gay yeu dan Giai doan sau

di thao nhieu han va gay rat nhanh Kiem tra lam sang thay gan sung to va dau Cd the thay hien tugng xay thai d bd cai bi benh, lugng sua cd the giam 30 - 50% Trieu chumg than kinh cung cd thd gap song rat hie'm Benh keo dai nhieu thang, con vat cd thd chet

do suy nhugc toan than

Phan Dich Lan (1994, 2004) da theo doi 37 trau bi benh san la gan nang thay cac trieu chumg thudng lap di lap lai nhu: gay rac, suy nhugc ca thd (37/37); phan nhao khong thanh khuon, co luc ia long (32/37); niem mac mat nhgt nhat, thieu mau keo dai

(27/37); long xu, da moc, long dd rung (26/37); phan den, thdi kham (22/37); mat sau,

co du (18/37); bung ong, ia chay keo dai (13/37); thuy thung 6 nach, hai chan truac, gan

to (11/37); thuy thung d nguc, ire lien tuc (9/37)

Nhin chung, khi sue vat bi benh san la gan keo dai, ca the suy nhugc nang, neu khong dugc didu tri kip thdi thi sue vat thuang chet

3.1.3 Benh tich cua trau, bd mac benh san la gan

Tuy theo muc do nhidm san ma benh tich co su khac nhau

Ddi vdi trau bd nhidm san nang, benh tich thay ro la viem gan ca'p tinh, gan sung to, mau nau slm , xung huyet Trdn mat gan cd the thay nhung dudng di hanh cua san non tao thanh nhung vet dd tham, dai 2 - 4 mm, trong cd san non vdi sd lugng nhieu Ldp thanh mac xua't huye't nhe, doi khi cd to huye't Khi nhidm nang thay viem phuc mac, gan xua't huyet nhieu, niem mac mat nhgt nhat

Hinh 49 San Fasciola ky sinh trong dng dan mat

cua trau

6 nhung sue vat nhidm san la gan da lau, gan viem man tinh, nhung chd mo gan bi pha huy cd seo mau vang xam Gan xa cung, niem mac dng dan mat day, cd hien tugng canxi hoa mat trong thanh dng Long dng dan mat gian rong, chua day dich mau nau va

san Fasciola Khi dng mat bi canxi hoa nhieu, san d chd dd thudng bi chet hoac chuydn

den chd it bien doi han

Hinh 50 Benh tich canxi hod dng dan mat do Fasciola gay ra

Ngoai gan va dng mat, ddi khi con th*y san 6 ph6i trau, bd Trudng hop nay san 6 trong nhung boc bang qua trumg ga hoac nho hon, trong chura dich mau nau.

Quan sat bien doi vi the dudi kinh hi£n vi tha'y: nhu md gan mat mau lien bao 6ng mat thoai hoa, niem mac tang sinh thanh nhumg u, trong u chura nhidu bach cau, lam ba cau, bach cau ai toan, dai thuc bao chura day sac t6' mat va mau Qua trinh viem tang sinh lan xuong ldp sau hon cua ong mat: to churc lien ket tang sinh, lan vao cac thuy gan lam tan bien to churc gan (Pham Van Khue va Phan Luc, 1996)

Nghien cuu benh san la gan d trau, bd, Phan Dich Lan (1994) cho biet: khi mo kham trau bo bi benh san la gan tha'y cd benh tich dac bidt la gan to ra't nhidu so vdi binh thudng (ga'p 2 - 3 ian) Gan mau do sam, bidu hien xung huydt Dudi vo gan tha'y ua nude, trdn mat gan cdn giu lai nhumg dudng ngoan nghoeo do san di hanh T6 chuc lifin kd't phat trien tao nen nhumg seo dac biet Trong gan cdn tha'y nhumg san non khdng d£n duoc dng dan mat, ddng ken va chet trong ken to bang hat dau Cat t6 chuc gan tha'y lao

xao do bien chat thoai hoa Do tang sinh to churc lidn kd't ndn gan ciing va xa gan

Trudng hop viem phuc mac xoang bung chua nhieu nude (c6 chudng)

Nguydn Thi Kim Thanh va cs (1996) da nghidn curu mdt sd chi tieu sinh ly mau cua trau bi benh san la gan, ket qua tha'y: so lucmg hdng cau giam, ham lupng huye't sac t6

giam, so lupng bach cau tang, cong thuc bach cau thay d6i nghieng ve bach c£u ai toan

3.2 Benh ly va lam sang benh san la gan d de

Phan Dich Lan, Nguydn Thi Kim Lan va cs (2002) da tong hop nhumg nghidn curu

ve benh san la gan cua dd dia phuong d mot so tinh midn nui phia Bac Vidt Nam Qua theo ddi benh ly va lam sang ciia nhieu dd bi benh, cac tac gia cho bie't: sau khi de

nuot phai ken Adolescaria vai ngay, san non di hanh gay ton thucmg thanh ruot, thanh

mach quan, nhu md gan, lach, phoi, co hoanh, tuyen tuy, gay xuat huye't nang hoac nhe Thudng tha'y dd bi viem gan, thieu mau do xuat huye't San trudng thanh kich thich niem mac dng dan mat, gay viem ong dan mat Cd nhung dd bi tac ong mat do s6

lupng san qua nhieu, mat tha'm vao mau, sinh ra hoang dan San thudng xuyen tiet doc

to lam bien doi thanh ong dan mat va md gan Doc to hap thu vao mau gay trung doc

toan than Doc to cdn pha hoai mau, lam tang bach cau Eosin va nhiet do co the Doc

to tac dong vao than kinh cua dd, tac dong vao cac thuy gan lam to churc lidn ket tang

sinh, thoai hoa nhu md gan, gay xa gan, chuc nang gan bi pha huy dan den rdi loan co

nang da day va ruot

Theo Holmes P H va cs (1968), dd ciru bi benh Fasciola cd trieu chumg thi£u mau

nang va thay doi protein huye't thanh Thieu mau la do san non di hanh gay xua't huyet

va san trudng thanh hut mau ky chu Lupng mau ma mdi san doat cua ky chu xap xi 0,5ml/ngay

Reid J F S (1973) cho bie't, cd su thay doi protein huyet thanh cua nhumg de bi

nhiem san la Fasciola Su thay doi nay xay ra sdm, ngay trong giai doan san non di

hanh Do la su tang Globulin va giam Albumin huyet thanh

Gay nhidm thuc nghidm san la Fasciola cho de va theo doi dien bien benh ly,

Rushton B va Murray M (1977) thay, su di chuydn cua san non da tao ra nhumg ducmg

di hanh 6 gan va pha huy ca'u true nhu mo gan, gay viem gan Sir di hanh cua san cung

- gay nghen tinh mach o gan va lam gan bi xung huyet Sau do, sir can tro mau chay dan den thoai hoa va hoai tir cac nhu mo gan Sir han gan va tai sinh cua nhumg ton thucmg nay bat dau vao khoang 4 - 6 tuan sau khi nhidm Xo gan phat trien vao khoang 1 2 -2 0 tuan sau khi nhidm

Vd lam sang, dd bi benh san la gan the hidn hai thd: the ca'p tinh, didn ra chu yeu a

giai doan san non di hanh; thd man tmh thucmg o dd trudng thanh Con vat an kem, co the suy nhugc, khong theo kip dan Con vat thieu mau, niem mac nhgt nhat, long xu va

dd nho Trieu chung ia chay thay 6 100% dd benh voi cac muc do khac nhau Thuy thung 6 nguc, nach va 4 chan (Nguydn Thi Kim Lan va cs, 1999)

Dd benh the hien ro viem gan, xo gan, gian mach quan, ong dan mat co nhieu san trong dich tiet, bieu mo cua ong dan mat tang sinh (Das P M., 1987)

Nghidn curu ve benh san la gan a de, Nguydn Thi Kim Lan va cs (1998) cho bie't, khi

dd bi benh san la gan, so lugng hong cau giam, ham lugng huyet sac to giam, so lugng bach cau tang, bach cau Eosin tang cao Mo kham 748 dd 1 - 4 nam tuoi, co 159 dd

nhidm san F gigantica Trong do co 42 dd co benh tich ro 6 gan, chiem 26,42% Benh

ti'ch dai the a gan dd nhidm san la Fasciola nang dugc tac gia mo ta nhu sau: gan dd

sung to, be mat gan go nghe, khong bang phang So gan tha'y cumg va tho hem so voi gan binh thugng Mau sac gan khong dong nhat, co nhumg vet trang xam loang lo hoac

nhung vet do tham trdn mat gan O bd mat va trong gan co nhung not hoai tir mau trang xam to bang hat dau xanh Ong dan mat viem va xo hoa, noi nhu day chang mau trang o mat dudi gan Cat gan tha'y dai va nghe tieng “soat” nhu cat xo muop Dung keo cat doc dng dan mat tha'y cung, thanh ong mat day len, xu xi, long o'ng mat chua day dich mau

nau sam, nhon va co nhieu san Fasciola Tac gia con cho bie't, trong 159 dd nhidm san la

gan mo kham, co 42 de phai huy bo gan do gan bi cung, viem va xo gan

H inh 32 Ong dan m at ndi nine clay chdng trong benh san Id Fasciola

ScTji la g o # ,

**'•&* */ttf

H inh 51 Sdn Id F gigantica ky sinh d o n g

dan m at cua de

Bidn d6i vi thd do san F gigantica a dd dtroc Nguydn Thi Kim Lan (2000) md ta

nhu sau:

San la gan ky sinh 6 ong dan mat vod s6 luong nhidu lam tic 6ng mat, lam cho dich

mat ii lai xung quanh cac huyet quan, gay ra huyd't khd'i trong cac mach quan gian thuy (hinh 53)

Hinh 53

San la gan ky sinh o ong dan mat lam cho dich mat ur lai, kich thich te' bao bidu m6

ong dan mat tang sinh, hinh thanh cac ong dan mat phu (hinh 54)

Hinh 54

Thanh ong dan mat bi so hoa, day va xu xl Te' bao bieu mo cua ong mat bi dut nat

do tac dong cua san Fasciola (hinh 55).

Hinh 55

Do ong dan mat bi tac, dich mat ur lai d quang cira, quan sat tha'y ro mau vang cua dich mat (hinh 56).

Hinh 56

Tac dong ca hoc va doc to cua san Fasciola kfch thich, lam tang sinh cac te bao

viem va cac te bao xa xung quanh dng mat, dac biet la tang sinh nhieu bach cau ai toan (hinh 57)

Hinh 57

Thanh dng mat cung co nhung bien doi r5 ret Dd la su tang sinh cac te bao x a va te bao viem d thanh dng mat Su cd mat cua rat nhieu bach cau ai toan d thanh dng mat rat dac trung cho phan ung cua c a the ddi vdi tac dong cua giun san (hinh 58).

Hinh 58

4 CHAN DOAN BENH DO FASC IO LA GAY RA 6 SUC VAT NHAI LAI

Viec chin doan co the tien hanh tren sue vat con sdng hoac da chet Tuy dieu kien thuc te ma ap dung bien phap phu hop

- Ddi vdi sue vat con sdng:

De chin doan benh do Fasciola gay ra, thudng ap dung cac bien phap nhu: chan

doan lam sang, ket hop dac di£m dich te hoe, xet nghiem phan con vat nghi benh va chin doan mien dich hoc

Trieu chung lam sang cua benh san la gan thudng tha'y nha't la: kiet sure, suy nhuoc, rung long, phu thung d nguc, lie Tuy nhien, cac bi£u hien tren khdng chi tha'y d benh

do Fasciola gay nen Vi vay, trieu churng lam sang khdng phai la can cu duy nha't de’ ket

luan benh

Nhung dan lieu dich te hoc cua benh can xem xet la: yeu td mua vu, vung va tu6i sue vat benh Song, nhung dan lieu nay chi la nhung thdng tin can xem xet trong chan doan chur khdng phai la sd cti quan trong nha't trong chin doan

Viec xet nghiem phan tim triing Fasciola la bien phap cd tfnh quyet dinh trong chan

doan Thudng dung phuang phap gan rira nhieu l£n Theo Pham Van Khue va cs (1996), phuang phap nay pho bie'n nhung chua phat hien duac ta't ca moi gia sue nhiem san

Fasciola, nha't la d nhung sue vat nhiem ft hoac d giai doan san cdn non Khi xet nghiem

phan, eln phan biet trung Fasciola vdi trung Paramphistomum ky sinh d da cd (phan

biet ve mau sac, hinh dang, te bao noan hoang va kfch thudc)

Phuang phap mien dich hoc de phat hien sue vat nhiem Fasciola da duoc sir dung

la: dung khang nguyen tiem noi bi, can cur vao phan ung d noi tiem de ket luan Cac phuang phap khac nhu: phuang phap mien dich men ELISA, phuang phap mien dich huynh quang Tuy nhien, do kho khan ve phuang tien va viec che khang nguyen chuan nen cac phuang phap nay cdn ft duac dimg trong benh ky sinh triing ndi chung va benh san la gan ndi rieng

- Ddi vdi sue vat chet:

Khi sue vat chet, mo kham tim san Fasciola d giai doan au triing va trudng thanh

trong dng dan mat, gan, xoang bung Phuang phap nay chfnh xac han ca, vi tim tha'y

ca san non d giai doan di hanh

5 PHONG VA TRI BENH SAN LA GAN

5.1 Dieu tri benh

Hien nay, cd the tay san la gan cho sue vat nhai lai bang mot trong cac loai thudcsau:

- Thuoc Dertil: Dertil la thuoc cd tac dung dac hieu vdi san la gan Fasciola Ten

khac: Menichlofolan, Bayer ME 3625, Bayer 9015A, Bilevon M

Dertil dugc bao ch£ thanh vien to, mau xanh la cay dam Vien Dertil “0 ” co chura

100 mg hoat chat, vien Dertil “B” chira 300 mg hoat chat.

Dertil co tac dung diet san la gan trucmg thanh a gia sue nhai lai, voi lidu cao con diet dugc ca san non dang di hanh trong nhu mo gan Thuoc chi can dung mot lan, khong can dieu tri lap lai Dugc chi dinh dieu tri benh san la gan cap tmh va man tfnh cho gia sue nhai lai.

- Thuoc Fasciolid (ten khac: Fasciolidum)

Thuoc dugc bao che duoi dang dung dich mau vang nau, chua 25% hoat chat la Nitroxynil.

Fasciolid co tac dung tay san la gan Fasciola dang trucmg thanh va cac giun tron duang tieu hoa loai nhai lai, dugc chi dinh tay san la gan cho gia sue nhai lai.

Lieu lugng: 0,04 m l/kgTT (1 ml/25 kgTT, tucmg duong 1 mg hoat chat/kgTT) Tiem duPi da.

De tly san la gan, nen dung thuoc 2 - 3 lan, cach nhau 25 - 30 ngay.

- Thuoc Tolzan - F (che pham cua Oxyclozanid), dugc bao che duoi dang dung dich hoac vien nen, dung vgi lieu 1 0 - 1 1 mg/kgTT Thuoc co tac dung dac hieu voi san

Fasciola trucmg thanh va san non a trau, bo, de, cuu.

Hien nay, tren thi trucmg thuoc thu y tha'y pho bien thuoc Tolzan - F dang vien nen,

cho uong tay san F asciola voi lieu 1 vien (1000 mg)/90 - 100 kgTT.

Tolzan - F da dugc su dung cho trau, bo a nugc ta, song chua co ket qua nghien cuu thu nghiem tay san la gan cho de, vi vay can thu nghiem truac khi dung dai tra.

- Thuoc Fasinex (che pham cua Triclabendazole): thuoc co tac dung diet ca san non

va san trucmg thanh ky sinh a ong dan mat hoac dang di hanh trong cac nhu mo gan.

Fasinex dugc chi dinh dung dieu tri benh san la gan cho sue vat nhai lai.

Li&u lugng: 1 0 - 1 2 mg/kgTT Cho uong mot lan duy nhat.

Thuoc co hieu luc cao va an toan cho gia sue dung thuoc.

Ngoai cac thuoc tren Albendazole, Bithionol, Closantel cung co tac dung tay san

la Fasciola a sue vat nhai lai.

L u ang To Thu va cs (1997) da nhan dinh ve cac thuoc tri san la gan va ket qua thu nghiem a trau, bo Viet Nam Cac tac gia khuyen cao rang, tren thi truang Viet Nam hien

nay n6n su dung Fasinex - 900 dang vien (1 vi6n/75 - 100 kgTT) hoac Fasinex - 900

dang sua (10 mi/100 kgTT), cho hieu luc cao

Sir dung Fasinex lidu 12 mg/kgTT t4y san la gan cho trau, Phan Luc va Trdn Ngoc Thang (1999) cho biet, thuoc co hieu luc va hieu luc tay sach san deu dat 100%

Nguyen Thi Kim Lan va cs (2000) da thu nghiem mdt s6 thu6c tay san ia gan cho de

dia phuong d tinh Thai Nguyen va Bac Kan, ket qua tha'y: thuoc Dertil (lidu 5 - 8

mg/kgTT) co tac dung tly sach 100% va an toan doi vdi de; thudc Fasciolid (lidu 0,04

ml/kgTT) co hieu luc tly sach la 95% va tuong doi an toan cho de; thuoc Vermitan

(chuta 20% Albendazole, lieu 35 mg/kgTT) dat hieu luc l&y sach va an toan deu la 100%,

ngoai ra Vermitan con co tac dung tly ca san day va giun tron 6de.

5.2 Phong benh san la gan Fasciola

Ca so khoa hoc de ra quy trinh phong ngira tong hop benh san la gan cho sue vat

nhai lai la: phai nam dupe cu thd chu ky sinh hoc cua san Fasciola, sinh hoc cua 6c - vat

chu trung gian va tinh hinh dich te cua benh

Bien phap phong ngira tong hop gom:

- Dinh ky tly san la gan cho sue vat nhai lai de ngan chan mam benh phat tan r6ng rai, dong thdi phong ngira cho sue vat khong bi tai nhiem

Theo Pham Van Khue va cs (1996), hang nam nen tly san cho toan dan it nha't 2 ian, ian dau vao mua xuan (trudc miia vat chii trung gian phat trien), Mn thu hai vao cudi

mua thu nham diet nhung san da nhidm trong vu Xuan - He, ngan ngira benh phat ra a

mua ddng Tren nhung ddng co cd can benh tidm tang, co thd tien hanh chan dat luan phien giffa sue vat man cam (trau, bo, de, ciru) vdi nhung sue vat it kha nang cam nhidm (ngua)

•>

- U phan theo phuong phap sinh hoc, loi dung qua trinh len men sinh nhiet cac chat huu co trong phan cua he vi sinh vat de tieu diet trumg san la gan trong phan sue vat nhai

lai Bien phap nay co hieu qua va don gian nhat de phong benh do san Fasciola gay ra.

- Xir ly cac co quan cd san ky sinh: neu gan nhidm nhidu san phai huv bd (chon, rac vdi bot, dot) hoac khdng huy bo ma de lai che bien chin lam thirc an gia sue

- Diet vat chii trung gian cua san la Fasciola: thao can nude, lam kho nhumg ddng

co, bai chan lay loi, am udt Dimg mot sd chat hoa hoc cd kha nang diet oc (vdi bot, sulfat ddng ), day manh chan nudi thuy cam (vit, ngan, ngdng) va ca tram den

- Tang eucmg ve sinh thurc an, nude uong Khdng chan tha sue vat nhai lai a nhumg

bai chan lay loi, am thap Neu kho khan vd bai chan tha thi chi chan d bai chan lay loi,

am udt 1,5 - 2 thang, rdi phai chuydn sang chan d bai khac Neu la'y co a nhumg chd am udt thi phai cat cao hon mat nude de tranh Adolescaria, sau dd phoi kho, bao quan trong

6 thang rdi cho gia sue an Nguon nude uong phai sach, khdng cd vat chii trung gian va

Adolescaria.

- Khdng nhap sue vat nhai lai tir viing eo benh, khi chua kiem tra va didu tri triet de

TAI LI$U THAM KHAO CHl/ONG 7 (B$NH SAN LA GAN)

3 Nguydn Trong Kim (1997), Nghien cuu su lien quan giua ty le nhidm au trung san la gan d

6c (KCTG) vdi ty le nhidm san la gan a trau bo (KCCC) de’ danh gia tinh hinh dich td cua

benh m6t s6 vung a mien Bdc Viet Nam, Luan an Tien sy nong nghiep, Vien khoa hoc ky thuat n6ng nghiep Viet Nam, Ha Noi.

4 Nguydn Thi Kim Lan, Phan Dich Lan, Nguydn Khanh Quae, Nguydn Van Quang (1998),

"Nhan xet ve benh tich dai the va mot so chi tieu huyet hoc cua de nhiem giun san tieu

5 Nguydn Thi Kim Lan, Phan Dich Lan, Nguydn Khanh Quae, Nguydn Van Quang (1998),

“Bien dong nhiem giun san dudng tieu hod d dan de Bdc Thdi theo tuoi, mua vu vd tinh biet", Tap chi khoa hoc ky thuat Thu y, tap V, s<5 1, Tr 73 - 80.

6 Nguydn Thi Kim Lan, Phan Dich Lan, Nguydn Khanh Quae (1999), “Phat hien benh giun san duang tieu hod d de vd dung thudc dieu tri", Tap chi' khoa hoc & cong nghe, Dai hoc Thai Nguydn, 1 (9), Tr 42 - 48.

7 Nguydn Thi Kim Lan (2000), Benh giun, san ducmg tidu hoa cua de dia phuang a mot so tinh mien nui phi'a Bac Viet Nam va bien phap phong tri - Luan an Tien sy nong nghiep, Ha N6i.

8 Nguydn Thi Kim Lan, Phan Dich Lan (2000), “Ket qua thu nghiem mot s d loai thudc dieu tri benli giun san d dudng tieu hod de ”, Tap chi khoa hoc ky thuat thu y, tap VII, sd 4, Tr 48

-52.

9 Phan Dich Lan (1994, 2004), Benh nga nude trau, bd. Nha xuat ban nong nghiep, Ha Noi,

Tr 5 - 55.

10 Phan Dich Lan, Nguydn Thi Kim Lan, Nguydn Van Quang (2002), Benh ky sinh trung d dan

de Viet Nam, Nha xuat ban nong nghiep, Ha Noi, Tr 31 - 42.

11 Doan Van Phuc (1980), “Dimg DertilB tay san la gan cho bd", Ket qua nghidn cuu khoa hoc va ky thuat thu y (1968 - 1978), Nha xuat ban nong nghiep Ha Noi.

12 Doan Van Phuc, Nguydn Thi Hien Thao, Vu Thi Than (1980), 'Dung D ertil B cho uong tay san la gan trau Viet N a m ”, Ket qua nghien cuu khoa hoc va ky thuat thu y (1968 - 1978), Nha xua't ban nong nghiep, Ha Noi.

13 Doan Van Phuc, Vuang Due Chat, Duong Thanh Ha (1995), “Ket q u a dieu t r a n h i e m s an la

g a n trail, bo khu vuc Hd Noi vd Ung d u n g dieu t ri ", Cong nghiep & nong nghiep thuc pham, Tap chi khoa hoc cong nghe va QLKT, Ha Noi, 1/1995, tr 36 - 37.

14 Skrjabin K I va Petrov A M (1977), Nguyen ly mdn gum trdn thu v (Bui Lap va Doan Thi Bang Tam dich tu nguyen ban tieng Nga), Tap 1, Nha xua't ban khoa hoc va ky thuat, Ha Noi Tr 56 - 57.

15 Nguydn Quang Sue, Nguydn Thd Hung (1995), “Tinh hinh stic khoe va kha nang ch6ng chiu bdnh cua dan dd Bach Thao sau han 3 nam nu6i 6 midn Bac Vidt Nam” Tap chi khoa hoc ky thuat Thu y, tap II, sd 3, Tr 77 - 78.

16 Nguydn Thi Kim Thanh, Phan Dich Lan, Truang Xuan Dung, Trin Thi Lai (1996) "Mdt sd

chi tieu sinh ly mau cua trau mac benh san la gan ", Tap chi' khoa hoc ky thuat thu y Tap

19 Luang T6 Thu, Bui Khanh Linh (1996), ‘Tinh hinh nhiim san la gan (Fasciola) va ket qua

thu nghiem Fasinex tay san la gan cho trau bd ", Tap chi' khoa hoc ky thuat thu y Tap III, s<5

1, Tr 74-81

20 Luang T6' Thu, Doan Van Phuc, Norman Anderson (1997), “Nhan dinh ve cdc loai thuoc tri

san la gan vd ket qua thu nghiem tren trau bd oViet Nam ", Tap chi' khoa hoc ky thuat thu y,

tap IV, s6' 3, Tr 6 - 15

21 Phan Th£ Vidt, Nguydn Thi Ky, Nguydn Thi Ld (1977), Giun san ky sinh a dong vat Viet

Nam, Nha xua't ban khoa hoc & ky thuat, Ha N6i, Tr 153 - 168

* Tieng A nh

22 Das P M., Dewan M L (1987) Pathology of goat liver, Bangladesh veterinary Journal 21,

P 3 -4 , 19-26

23 Holmes P H., Dargie J D., Maclean J M„ Muligan W (1968), The anaemia of

Fascioliasis: Studies with 51 Cr labelled red cells, J com, Path, 78, P 415 - 420.

24 Jorgen Hansen and Brijan Pery (1994), The epidemiology, diagnosis and control of Helminth parasites of Ruminants Hand book, P 32 - 33

25 Kaufmann J., (1996), Parasitic infections of domestic animal Birkhauser Verlag, Basel,

Boston, Berlin P 90 - 94

26 Reid J F S (1973), Fascioliasis: Clinical aspect and diagnosis in helminth diseases of

cattle, sheep and horses in Europe, ed, Urquhart G M & Armour J., Glasgow, Maclehose,

P 81 - 114

27 Rushton B., Murray M (1977), Hepatic pathology of a primany experimental infection of F

hepatica in sheep and goats J, Comp, Path, 87, P 459 - 470.

28 Soulsby E J L (1982), Helminth, Arthropods and Protozoa of domestic animal, Lea,

Febiger - Philadelphia, P 40 - 71

BENH SAN LA RUOT LON

(Fasciolopsiasis)

Benh san la ruot lgn do loai san la Fasciolopsis buski gay ra Benh pho bien a hau

het cac nude a khu vuc chau A va Dong Nam chau A.

San la F buski duac bac sy Busk phat hien nam 1783 a ta trang cua nguai Tu do

den nay, co nhidu nha khoa hoc tap trung nghien cuu: Lankester (1957), Cobbol (1859), Looss (1899), Nakagawa (1921), Barlow (1925), Hua Bang Nhu (1964), Tran Tam Dao (1965), Muttalib (1975), Idris (1980), Li (1981), Grazick (2000)

Tac hai cua san la lam lan sinh truang cham, tham chi sut can Ngoai lan, nguai va mot so dong vat khac cung nhidm va bi benh

1 DAC DIEM SINH HOC CUA SAN LA FASCIO LO PSIS BUSKI

1.1 Vi tri cua F buski trong he thong phan loai

Theo Skrjabin va cs (1977), Phan The Viet va cs (1977), Nguydn Thi Le va cs

(1996), san la ruot Fasciolopsis buski dugc xep trong he thong phan loai dong vat hoc

nhu sau:

Nganh Plathelminthes Schneider, 1873

Phan nganh Platodes Leuckart, 1854

Lop Trematoda Rudolphi, 1808

Phan lap Prosostomadidea Skrjabin va Guschanskaja, 1962

Bo Fasciolida Skrjabin et Schulz, 1937 Phan bo Fasciolata Skrjabin et Schulz, 1937

Hg Fasciolidae Railliet, 1895 Phan ho Fasciolopsinae Odhner, 1910 Giong Fasciolopsis Looss, 1899 Loai Fasciolopsis buski (Lankaster, 1857)

1.2 Dac diem hinh thai va chu ky sinh hoc

1.2.1 Dac diem hinh thdi

F buski co mau do hong, phia truac ca the thon nho, phinh rong a phia sau, tren

than phu nhung gai nho Ca the dai 20 - 70 mm, rong 14 - 15 mm, day 0,3 - 3 mm Co 2 giac bam: giac mieng nam a phia truac ca the, co duang kinh 0,51 mm; giac bung lan han giac mieng, nam a phia sau, ducmg kinh 1 ,5 - 2 mm Ruot phan hai nhanh chay doc hai ben than, keo dai tai cuoi ca the

Cung nhu hau het cac san la khac, F buski luong tinh va co he sinh due phat trien.

Co quan sinh due due gom hai tinh hoan phan nhanh, xdp trdn dudi o phan sau than san Co quan sinh due cai co bu6ng trung phan nhanh nam trudc tinh hoan tu cung phan

nhanh, tuyen noan hoang phan nhanh nam doc hai bdn co th£ F buski thu tinh cheo

hoac tu thu tinh (hinh 59, 60, 61, 62).

Nhung nghien curu thuc nghiem d Trung Qud'c cho tha'y, F

buski phat trien tot nhat d Ion Cac dong vat khac nhu trau, tho,

cho tuy bi nhidm nhung san khong the phat tridn den trudng

thanh Trong co the meo, san khong sinh trudng duoc F buski

ky sinh d lpn va ngudi Viet Nam co kich thudc ldn hon san ky

sinh d lpn va ngudi Trung Quoc (D6 Duong Thai va cs, 1978)

Mathis va Leger (1911) cho bie't, F buski dai 30 - 70 mm, rong

14 - 15 mm Song, theo Phan Trong Cung (1991), chieu dai san

F buski a lpn Viet Nam khong qua 40 mm.

1.2.2 Chu ky sinh hoc

Chu ky sinh hoc (vong phat tridn) cua F

buski tuong tu cac san la khac thuoc ho

Fasciolidae.

San trudng thanh sdng ky sinh d ruot non,

de trung Trung theo phan ra moi trudng ben

Hinh 62 F buski tnrang thanh thu thap ti( td trang lan benh

F buski trirdng thanh thudng ky sinh d doan ta trang va

khong trang cua lpn va ngudi, nhung ky sinh nhieu nhat d ta

trang Trinh Van Thinh (1969), D6

Duong Thai (1973) cho biet, doi khi tha'y

san d da day va ruot gia

Hinh 61 F buski nhuom carmin

ngoai Sau mot thai gian a'u trung Miracidium hinh thanh trong trumg Au trung thoat

khoi trung bai trong nuoc, tim va xam nhap vao oc - KCTG thich hop Trong oc, au

triing phat trien thanh Sporocyst, roi thanh Redia me, thanh Redia con Redia con chua nhidu Cercaria Cuoi cung, Cercaria thoat khoi oc, bai trong nude, bam vao cac cay thuy sinh va tao thanh Adolescaria.

Chu ky sinh hoc (vong phat trien) cua F buski duac mo phong theo sa do sau:

S a do bieu d iin chu ky sinh hoc cua san la Fascilopsis buski

- Trung F buski:

Trung hinh bau due, mau vang chanh, co mot nap, dai 130 - 140 (am, rong 80 -

85 pm (Gilman va cs, 1982) Trung phai rai vao nuoc mai tiep tuc phat trien duac

Trong trung hinh thanh mot phoi thai co tiem mao goi la M iracidium M iracidium

thoat khoi trung sau mot thai gian tuy dieu kien khf hau ben ngoai Nhiet do thich

hap de trung F buski phat trien la 28°C (Nakagawa, 1921) Trong dung dich NaCl 5%0, nhiet do 28 - 30°C, trung F buski phat trien thanh M iracidium can 14 ngay,

nhiet do de trung phat trien tot nhat la 25 - 29°C (Nguydn Trong Noi, 1966; Pham Van Khue, 1971) Trong nuac cat, trung phat trien thuan lai a 35°C, ty le trung na

dat 82,2%; thdi gian phat trien tai M iracidium mat 12 - 13 ngay 6 30°C co 79,9%

trung na, thai gian phat trien thanh M iracidium mat 15 ngay 6 40°C trung khong

phat trien duac O 28 - 30°C, trung phat tridn thanh M iracidium can 15 ngay (Phan

Trong Cung va cs, 1991) C) moi truang co pH la 6 - 7, trung phat tridn rat thuan lai; a moi truang co pH la 4 - 5 va 8 - 10, trung khong hinh thanh M iracidium

(Phan Luc, 1976)

Hinh 63 Trung F buski (10 x 2 0 ) Hinh 64 Tri'cng F buski (10 x 10)

- Miracidium

Sau khi hinh thanh trong trung 3 ngay, Miracidium bat d£u chuydn ddng, sau 10 ngay mot so Miracidium thoat ra khoi trung, phan ldn thoat ra sau 12 ngay (Nakagawa, 1921) Miracidium hinh qua le, ben ngoai phu mot ldp mang mong cd nhieu ldng to, ben

trong cd he tieu hoa so sinh, mo thin kinh, hai te bao ngon lira va ra't nhieu te bao phdi

Mua he, Miracidium song duoc 6 - 8 gid; miia ddng sdng dupe 3 ngay Thdi gian hoat dong manh nhat trong nude la sau khi nd 1 - 2 ngay Day cung la thdi gian kha nang

xam nhap ciia Miracidium vao vat chu trung gian la nhieu nha't, sau dd yeu dan Theo Gilman va cs (1982), Miracidium xam nhap vao oc qua ldp ao co, rau va chan cua oc Trong dieu kien khi hau Viet Nam, sau khi thoat khoi triing, Miracidium hoat dong

trong nude 6 - 52 gid Sau dd, Miracidium phai xam nhap vat chu trung gian mdi tiep tuc

phat trien dupe

Hinh 65 Trung co Miracidium

(10 x 20)

Hinh 66 Miracidium thoat khoi trimg

(10 x20)

M

i' Sp>orocyst

Sau khi xam nhap vao v$t chu trung

gian 2 ngay, Miracidium hinh thanh

Sporocyst.

Sporocyst co hinh dang rS't thay doi,

gom nhung dam bao to, nho, khong co

ong tieu hoa Sau mot thai gian, cac te bao

hinh thanh ong tieu hoa dan gian, khong

chia nhanh, co 1 giac, goi la Redia me.

- Redia me va Redia con

Redia me co hinh ban nguyet, xam

nhap vao gan, tuy cua oc ky chu trung gian

va bien thanh Redia con, ben trong chua nhieu Cercaria Redia con co hinh ban nguyet uon khue, ben trong co chura cac Cercaria da thanh thuc.

Cercaria duac hinh thanh trong gan oc

sau 28 - 36 ngay (Graczick, J K va cs, 1982)

Cercaria giong con nong noc (au trung luong

the), ca the chia 2 phan la than va duoi, than

co ruot che doi, co 2 giac bam Theo Thai

Tran Bai va cs (1975), a dieu kien khf hau

mien Bdc Viet Nam, trong oc Planorbis

hemisphaerula,

Cercaria dai 231 - 382 pm, rong 231 -

297 pm, duoi dai 660 pm, rong 73 pm

Cercaria a gan oc vai ngay roi thoat khoi oc,

Hinh 69 Redia con ( 1 0 x 6 )

f

*

Hinh 70 Cescaria (10 x 10)

Hinh 77 Adolescaria (JO x 10)

chuyen dong rat manh, sau thcri gian

ngan rung du6i, tiet chat nhdn bao

quanh va bien thanh Adolescaria.

- Adolescaria

Adolescaria co hinh tron, dep, co

giac mieng va giac bung, h£u, thuc

quan, ruot, ong bai tiet Thdi gian hinh

thanh Adolescaria la 3 gid

Adolescaria

bam vao cay co thuy sinh: cac loai

beo, rau muong, rong O Viet Nam,

Adolescaria dupe tim thay 6 rau

muong, beo Nhat Ban, beo cai, beo

tam

ThPi gian hoan thanh vong dpi cua F buski d lpn la 90 ± 6 ngay (Pham Van Khud,

1964, 1967; Nguydn Thi Le, 1977)

Theo Barlow (1925), Trln Tam Dao (1966), Gilman (1982), Weng (1989), thPi gian

hoan thanh vong doi cua F buski a lpn la 3 thang, 6 nguPi la 31 ngay

1.3 Vat chu trung gian cua F buski

Vat chu trung gian cua F buski la cac loai oc nude ngot.

Oc nuPc ngot thuoc lop chan - bung, gom hai phan IPp: Probranchia (oc mang trudc) va Pulmonata (oc co phoi).

Co the oc tap trung thanh khoi, dupe bao boc boi lop vo da voi, kfch thuoc Ion nho khac nhau tuy theo timg loai Nhirng oc song d nuPc ho hap bang mang 6 can ho hap bang phoi Mot phan co thd oc phan hoa thanh chan (la co quan van dong)

Trong nuoc, oc song d nhung do sau khac nhau, thdi gian hoat dong cua chung cung khac nhau Ban dem, do cac loai thuc vat song trong nuoc hap thu oxy, thai khf cacbonic nen phan Ion cac loai oc tai, oc dia phai noi ldn mat nude de ho hap Oc thudng bam vao cac vat noi trdn mat nuPc nhu la beo, cay co cho den 9, 10 gid sang hom sau moi chim xuong cac ting nude sau hon Mot so loai oc tai, oc dia thuPng bam vao cac cay beo Nhat Ban, rau muong, rau lap, rong d cac ao, ho, song, suoi Chung co the d noi am udt (khong ngap nude) trong mot thdi gian dai (Dang Ngoc Thanh va cs, 1980) Thuc an cua

oc nude ngot la rong reu, beo, cac chat miin

Theo Phan Trong Cung va cs (1991), oc nude ngot sinh san huu ti'nh, phan ldn la don tmh, mot so loai ludng ti'nh nhung khong tu thu tinh

D6 Duong Thai va cs (1978) da t6ng hop ket qua phat hien ciia Barlow (1925) Tran Tam Dao (1956), Hua Bang Nhu (1964) ve oc ky chu trung gian cua san la ruot 1cm d

Trung Quoc gom cac loai: S nitidella, G chinensis, H cantori, H umbilicalis,

hemisphaerula

Theo Phan Luc (1976), Nguydn Thi Le (1986), 6 Viet Nam, oc P hemisphaerula, G

sinensis va G heudei la ky chu trung gian cua san la ruot lpn Ty le nhidm Cercaria ciia

oc P hemisphaerula b khu vuc trong rau xanh nuoi lpn co lidn quan tdi tinh hinh su

dung phan bon co u hay khong u va muc do bon phan d khu vuc do Oc ky chu trung

gian co kfch thuPc cang ldn thi ty le nhidm Cercaria cang cao Trong tu nhien thudng tha'y oc P hemisphaerula b cac ao co beo Nhat Ban, chung thuong tap trung d ke la beo,

nha't la cac la beo dang thdi rua O ruong muong cd muc nude nong, pH 6 - 7, oc thudng tap trung d cong, la rau dang thoi rua 6 cac ruong muong dang trong thdi ky kho han, dat da nut ne, oc thudng tap trung d goc muong, ty le oc song la 90,3% Trong ruong rau

2 DICH Tfe HOC CUA BENH F BU SKI

F buski gay benh cho ca ngudi va dong vat d Trung Quoc, Hong Kong va Dai Loan

(Lee, 1989; Li, 1991)

6 Viet Nam, F buski phan bd rat rong d hau het cac tinh, thanh thuoc viing nui,

trung du va ddng bang trong ca nude Benh pho bien d lpn viing ddng bang Bac Bo va Thanh - Nghe - Tinh 6 ngudi, ty le nhidm F buski rat thap (Pham Sy Lang va cs, 1997).

Su phan bo cua san la ru6t lpn thucmg theo quy luat vung Benh thudng xua't hien a

cac nude khf hau nhiet ddi, nhiing vung co nhidu ao, h6, co nhidu cay thuy sinh dung

lam thuc an song cho ngudi va lpn Vung dong bang ven bi<?n lpn nhiem F buski tha'p.

2.2 Miia, tuoi nhidm va ky chu cuoi cung

Lpn va nguoi nhidm F buski khong bieu hien bien d6ng theo mua ro rdt (Dd Duong

Thai va cs, 1978), co the nhidm 6 ca 4 mua, nhung ty le nhidm giam vao thang 5, 6, sau

do tang dan va tang cao nha't d thang 9, 10, sau do lai giam dan (Pham Van Khue, 1982,

1996)

Theo Trinh Van Thinh (1967), Phan Dich Lan va cs (1974), d nude ta, F buski ky

sinh nhidu nha't d lpn sinh san va lpn thit; d lpn dang bu sua me, lpn mdi cai sira va lpn choai ft nhidm hon

Ty le nhiem F buski tang dan theo tuoi Lpn dudi 2 thang tu6i nhiem 16,6%; 3 - 4 thang nhiem 45,8%; 5 - 7 thang nhiem 58,3%; lpn tren 8 thang nhiem 70,8%

Khong co sir khac nhau ve ty le nhidm F buski giua cac gidng lpn dia phuong va lpn

nhap tu nude ngoai (Pham Van Khue, 1971; Phan Dich Lan, 1974; Luong To Thu, 1976)

2.3 Nguon benh, sure de khang cua trihig va Adolescaria

Ngu6n phat tan m lm benh chu yeu la lpn va ngudi co san ky sinh

Hang ngay, m6i san trudng thanh thai theo phan ra moi trudng ben ngoai 15.000 - 18.000 triing Mot triing san khi gap dieu kien thuan lpi cua moi trudng ben ngoai se phat trien thanh nhieu mam benh co kha nang gay nhiem (Pham Van Khue va cs, 1996) Phan lpn va phan ngudi nhidm san la nguon phat tan mam benh ra moi trudng ben ngoai

Vi vay, quan ly va xu ly phan lpn va nguoi la bien phap chu dong ngan chan nguon benh phat tan ra ngoai canh

Trung cua F buski bi diet nhanh trong ho u phan vao mua he va cham hon vao mua

dong Phan lpn u theo phuong phap nhiet sinh hoc, khi nhiet dp dat den 50 - 54"C trung

F buski bi tidu diet Trong nude muoi NaCl 5% trung van phat trien dupe (Nguydn

Quoc Si, 1962), trung bi tidu diet khi di qua he thong u men sinh khf gas (Shinobu Yoshihara va cs, 1998; Nguydn Van Tho, 2003)

Adolescaria bi tieu diet khi anh sang mat trdi chieu true tiep 20 - 30 phut, trong

nude nong 60°C sau 15 phut, trong nude soi sau 60 giay Nhiet do 3 - 5nC Adolescaria song dupe 13 ngay Trong moi truong axit clohydric (HC1) 0,5%, Adolescaria sdng dupe

18 ngay; trong axit axetic 2% song dupe 9 ngay; trong axit axetic 3% sdng duoc 6 ngay; trong nude muoi NaCl 5% sdng dupe 3 gio; trong nude mudi NaCl 20% bi diet sau 30 ngay (Nakagawa, 1921)

2.4 Tap quan chan nuoi va dtftmg truyen benh

Lon nhiem F buski nang hay nhe phu thuoc vao tap quan cho an thuc an song hay

chin, thuc an xanh cho lgn tr6ng can hay dudi nuoc Lon an thuc an song ty le nhidm F

buski cao ga'p 3 - 7 lan so vdi Ion an thuc an nau chin Ty le nhidm F buski con phu

thuoc vao dieu kien ve sinh thu y, noi nao khong bon phan Ion tuoi thi ty le nhidm thap Lon 6 vung nui, vung trong mau thuong cho an rau o tren can nen ty le nhidm thap hon 6

vung d6ng bang Theo Pham Van Khue va cs (1996), Nguydn Thi Kim Lan va cs (1999) thi can u phan dung ky thuat va khong cho Ion an song cac loai rau beo lay tu nuoc len

de han che tinh trang Ion nhidm F buski.

Lon nhidm F buski do an song cac loai thuc vat nuoc nhu rau muong, rau lap, rong,

beo Nguoi nhidm san la ruot, ngoai viec an song rau muong, con do an song cu nidng,

ngo sen va cu a'u co mang Adolescaria (Shinobu Yoshihara va cs, 1998; Nguydn Van

Tho, 2002)

3 BENH LY, LAM SANG CUA BENH 6 LON VA NGUCII

3.1 d Ion

San F buski bam vao niem mac ruot non, gay ton thuang, viem cataz; dong thai san

lay duang cha'p a ruot non, tiet doc to' gay trung doc man ti'nh cho lan

Lan nhidm F buski thuang gay yeu, long xu, an uong that thuang, cham lan, sut

can, da san sui, niem mac mat nhgt nhat, thinh thoang ia chay Lan nhidm san vai cuang

do cao co the tac va loet ruot

Theo Hua Bang Nhu (1964), lan nhidm F buski sinh truang cham nuoi 5 - 6 thang khoi lugng chi den 1 3 - 1 5 kg/con Trinh Van Thinh (1967), (1985); Phan Trong Cung

(1991) nhan xet, F buski gay tac hai ldn cho lgn, trong 35 ngay bi benh, trung binh 1 san F buski lam lgn giam 65 gam khoi lugng.

Lgn nai nuoi con bi benh san la ruot thi thieu sua, ty le lgn con mac benh phan trang cao Lgn con sau cai sua thuong bi ia chay, coi coc, cham lan

Md lgn benh thay thanh ruot non day ldn, co nhidu diem hoai tir tren niem mac ruot.3.2 6 nguoi

Nguai nhidm san thuang co ton thuang ca the’ benh hoc ro ret Niem mac ruot non

bi phu va viem, xung huyet hoac xua't huyet Truong hgp nhidm nhieu san ruot bi tac neu co boi nhidm vi khuan thi cac hach mang treo ruot viem sung Doc to ciia san gay ton thuang va roi loan chung Toan than bi phu, tran dich a ngoai tam mac Benh nhan thieu mau, so lugng bach cau giam, huye't sac to giam, bach cau toan ti'nh tang San

chiem doat dinh dirdng, benh nhan c6 the ch£t trong tinh trang suy kiet (Trinh Van

-Benh san la ruot do F buski a nguoi didn ra qua 3 giai doan:

- Giai doan khoi phat: ngudi benh co trieu chumg nhe, biiu hien met moi, sue khoe

giam sut, thieu mau nhe

- Giai doan toan phat: ngudi benh dau bung kem theo ia chay, phan long, nhay va lan thurc an chua tieu hoa Hien tuong ia chay keo dai nhieu ngay Vung ha vi dau, bung chudmg, stic khoe giam sut nhanh chong

- Giai doan ket thuc: ngudi benh phu n6 toan than, tran dich 6 nhieu ndi tang, ngudi benh co the chet trong tinh trang suy kiet (D6 Duong Thai va cs, 1973)

4 CHAN DOAN B$NH SAN LA RUOT LON

Viec chan doan benh san la ruot 1cm khong kho khan, boi co the su dung phuong phap gan rua sa lang (phuong phap lang can Benedek, 1943) de phan ly trumg ra khoi phan Trumg san la ruot 1cm to va de phat hien dudi kmh hien vi (do phong dai 10 x 10)

De chan doan chfnh xac, can phdi hop xet nghiem phan tim trumg san vdi viec di£u tra tinh hinh dich te hoc Mot trong nhung dac diem dich te dang chu y nha't cua benh do

F buski gay ra la 1cm d khu vuc a'y co an sdng cac loai rau, beo la'y tu dudi nude len

khong? Vdi lem chet, viec mo kham tim san la ky sinh d ruot non la bien phap chan doan chfnh xac hon ca

5 PHONG TRI BENH SAN LA R U 0T LON

5.1 Bien phap phong benh

Phong benh F buski bang cac bien phap: chin doan phat hien vung co ngudi va Ioti nhiem san de dung thudc tly trir (tly san F buski cho Ion bang thudc Praziquantel, lieu

15 mg/kgTT); ve sinh chuong nuoi Ion, thurc an nude uong cho Ion; khdng cho lmi an sdng rau muong nude, rau la'p, beo Nhat Ban (ngudi can bo tap quan an song rau muong nude, cu au, ngo sen, cu nieng); tap trung phan 1cm, phan ngudi u theo phuong phap

nhiet sinh hoc de diet trumg F buski.

Nguyen Van Tho (2005) da de xuat bien phap phong benh san la ruot cho Ion nhusau:

- Dung thudc Praziquantel tay san la ruot: 1cm nuoi thit (3 - 6 thang tuoi) nen tay 1

lan vao thdi gian 2 - 2,5 thang tuoi Lon sinh san m6i nam tay 2 lln, khoang cach giua 2 lan tly la 4,5 thang Lem trong thdi ky mang thai khong nen tly vi chua cd ket qua thuc

nghiem v i anh hudng cua thudc d lom mang thai.

De giu cho moi truong khong bj o nhidm trung san, trong qua trinh dung thuoc tay cln thiet nhot Ion tai mot dia diem, thu gom phan, rac va xac san, tap trung u theo phuong phap nhiet sinh hoc, tly ue chu6ng trai.

- Chdng o nhidm trung san d moi trudng ngoai canh

+ Quan ly va xu ly phan Ion

Phan Ion nhidm san co chua nhieu trung, la nguon benh duy nhat Vi vay, phai tap trung phan Ion u theo phuong phap nhiet sinh hoc de diet trung

Cong thuc u phan:

Phan chuong: 2.000 kg

La xanh, co, ram rac: 200 - 300 kg

Voi bot, tro bep: 50 - 80 kg

Cach u: tron deu cac nguyen lieu tren (hoac cu mot ldp phan lan phu mot ldp la xanh, tro bep ) danh thanh ddng hinh khoi chop, phia ngoai cung trat mot ldp bun Sau

12 ngay, nhiet do ddng phan tang cao den 50 - 54°C 6 nhiet do nay, trung F buski va

cac trung giun san khac ddu bi tieu diet

+ Quan ly phan lan va diet trung F buski trong be Biogas

Trung F buski bi diet khi dugc giu trong be Biogas 30 ngay, neu bo sung che pham

EM nong do 1% vao bd Biogas thi thdi gian trung bi diet la 20 ngay Vi vay, can van

dong cac ho nuoi lgn xay dimg be Biogas de xu ly phan, diet trung F buski.

+ Quan ly va xir ly triet de’ nude rua chuong

Trung F buski co thdi gian luu giu ngan trong be Biogas, khi theo nude thai ra

ngoai vin con kha nang phat trien Vi vay, bien phap xu ly dan gian la xay 2 - 3 be’ chua nude thai trudc cira thai cua be’ Biogas de lam lang trumg, giu trung lai trong be ma khong cho phat tan ra ngoai canh

- Ve sinh thu y, quan ly va nuoi dudng tot dan lgn

Thudng xuyen coi trong cong tac ve sinh thu y, quan ly, nuoi dudng dan lgn; dinh

ky taiy san cho lgn bang thudc Praziquantel; khong cho lgn an song rau muong nude, beo Nhat Ban; diet oc ky chu trung gian bang cach lam kho can cac ao ruong trudc mua he

vi luc nay oc chua hoat dong va phan tan

5.2 Dieu tri benh

De su dung thuoc tay F buski cho lgn va ngudi co hieu qua can xay dung lich tay tru thfch hop vdi dieu kien cu the d vung co benh

O Viet Nam cac tac gia da xac dinh Wing, Dipterex va Dichlovos la nhumg thuoc tay

co hieu qua cao \ d i san F buski Cac thuoc nay da duoc dung o nuoc ta trong nhieu thap

ky Tuy nhien, nude ta da cS'm sir dung Dipterex v& Dichlovos tiy giun san cho gia sue Tir nam 2002 ddn 2005, chung ta chua xac dinh duoc thudc c6 tac dung tay san la ru6t

1cm co hieu qua

Nguydn Van Tho (2005) da bao cao ket qua nghidn ciru sir dung thu6c Praziquantel lidu 15 mg/kgTT tly san la ruot 1cm dat hieu luc 93,73%; ty 16 sach san dat 90%, thudc

co tac dung voi ca san non va san trudng thanh, d6ng thdi an toan vdi Ion Tac gia cung

cho biet, thudc Triclabendazole co hieu luc thap vdi san F buski (chi dat 36,84%; ty Id

sach san la 10%)

Tmh hinh sir dung thudc tay F buski d trong nude va nude ngoai dupe Udt ke d bang

sau:

Bang 6 Cdc thudc dd duac dung de tay F buski a lan va nguai

Tetrachlorua - cacbon

Trinh Van Thinh (1963)

Hat cau

Barlow C H (1925)

Hat thun mun

Do Di/dng Thai (1967)

Praziquantel

15 mg/kgTT Thai Lan

Dai Loan

Bunnag (1983) Lee (1989)

(2005)

G hi chu: (-): k h6n g tha'y d e cap d£n

(*): thud'c da c&'m su dung tir nam 2 0 0 2

TAI LlfcU THAM KHAO CHl/ONG 7 (BENH SAN LA RUOT LON)

* Tieng Viet

1 Thai Tr3n Bai, Tran Thi Nga, Phung Thi Hoan (1975), "Din lieu vi a'u trung san la rudt lgn

(Fasciolopsis buski Lankester, 1957) trong cac khu vuc tr6ng rau xanh cua m6t s6 trai lgn

vung d6ng bang", Tap chi khoa hoc & ky thuat nong nghiep (6), Tr 437 - 439

2 Thai Tr£n Bai (1977), "Cac loai hinh lay lan cua san la ruot Ion (F buski) qua khu vuc rau xanh a cac trai nudi 1cm vung d6ng bang s6ng H6ng", Tap chi khoa hoc & ky thuat nong nghiep (12), Tr 920-924

3 B6 n6ng nghiep & PTNT (2002), Ve viec ca'm mot so hoa cha't, khang sinh trong nhap khaiu, san xuat kinh doanh va su dung thuO'c thu y, Ha Noi

4 Pham Chirc (1978), "Ket qua xac dinh hieu luc va d6 an toan cua thuO'c Dichlovos o lgn Nam Bo", Th6ng tin Vien thu y (3), Tr 25 - 28

5 Phan Trong Cung, Le Manh Dung (1991), Sitih hoc dong vat, Nha xuat ban Dai hoc va Giao due chuyen nghiep, Ha Noi

6 Pham Van Khue (1971), Dich td va bien phap phong trir benh san la ruot Ion, thuc an sdng dung trong chan nu6i Ion, Nha xua't ban khoa hoc va ky thuat, Ha N6i

7 Nguydn Thi Le (1986), "Au triing san la d cac dong vat la vat chu trung gian trong cac thuy vuc viing Phiing Thuong (Phuc Tho, Ha Noi)”, Tap chi' sinh hoc, 8 (2), Tr 18 - 22

8 Nguydn Thi Le (1996), Giun san ky sinh d gia sue Viet Nam, Nha xuat ban khoa hoc va ky thuat, Ha Noi, Tr 68 - 70

9 Pham Sy Lang, Phan Djch Lan, Truong Van Dung (1997), Benh pho bien d Ion va bien phap phdng tri, Nha xua't ban nong nghiep, Ha Noi

10 Phan Luc (1976), "Mot so dac diem sinh hoc cua Fasciolopsis buski", Ky yeu khoa hoc &

ky thuat, Truong Dai hoc nong nghiep I, Ha N6i

11 Phan Luc (1993), "Ky sinh trung dudng tieu hod cua Ion vd hieu luc cua thuoc tay", Ky yeu

c6ng trinh nghien cuu khoa hoc (1991 - 1993), Truong Dai hoc nong nghiep I, Ha Noi

12 Hira Bang Nhu (1965), "Dieu tra benh san la ruot Ion d Quang Dong, Trung Quoc (Pham Van Khue dich),Tap chi' khoa hoc & ky thuat nong nghiep (2), Tr 245 - 249

13 Nguydn Trong Noi (1966), "Ket qua dieu tra nghien cihi san la rudt Ion", Tap chi' khoa hoc

& ky thuat nong nghiep, Tr 490 - 494

14 Doan Van Phuc (1980), Benh san la ruot Ion d V ie t Nam, Tuye’n tap cac c6ng trinh nghien cuu khoa hoc & ky thuat nong nghiep, Nha xuat ban nong nghiep, Ha Noi

15 Skrjabin K I va Petrov A M (1977), Nguyen ly mdn giun trdn thu y (Bui Lap va Doan Thi Bang Tam dich tir nguydn ban tieng Nga), Tap 1, Nha xuat ban khoa hoc va ky thuat, Ha Noi.Tr 56- 57

16 D6 Duong Thai (1967), "Chiet xuat axit Embilic tir qua chua ngut va didu tri san la ruot, giun dua bang amom embalat", Tap chi khoa hoc & ky thuat nong nghiep (6), Tr 358 - 361

17 D6 Duong Thai va tap the Bo mon Ky sinh trung, Trucmg DH Y khoa Ha Noi (1973), Ky sinh triing vu benh ky sinh trung d ngudi,Tap 1, Nha xua't ban Y hoc, Ha Noi

18 D6 Ducmg Thai, Trinh Van Thinh (1978), Cong trinh nghien cuu Icy'sinh trung d V ie t Nam,

Tap 2, Nha xuat ban khoa hoc & ky thuat, Ha Noi

19 Dang Ngoc Thanh, Thai Tran Bai, Pham Van Midn (1986), Dinh loai dong vat khdng xuong sdng nude ngot Bdc \ iet Nam, Nha xuat ban khoa hoc & kv thuat, Ha Noi

20 Trinh Van Thinh (1967), "Benh giun, san vd nang suat chan nudi". Tap chi' khoa hoc & ky thuat nong nghiep (6), Tr 136 - 138

21 Trinh Van Thinh (1969), 'Tinh hinh vd ket qua dieu tra caban ve ky sinh t r u n g a mien Bdc

Viet Nam", Tap chi khoa hoc & ky thuat n6ng nghiep (8), Tr 646 - 649.

22 Trinh Van Thinh (1985), Benh lan con or Viet Nam, Nha xuit ban khoa hoc & ky thuat Hi

N6i

23 Nguydn Van Tho (2002), "Moi giai truyen benh cua sdn Id rudt lan Fasciolopsis buski"

Tap chi khoa hoc ky thuat thu y, tap IX, s6 4, Tr 38 - 42

24 Nguydn Van Tho (2003), "Su phan tan va kha nang ph£t tri£n cua mOt s6 trung giun, sdn lpn

qua hd thdng Biogas", Tap chf khoa hoc ky thuat thu y, tap X, s6 3, Tr 22 - 27.

25 Nguydn Van Tho (2005), Khao sat m6t sd dac di&n sinh hoc, dich tS hoc, bien phap phdng trir Fasciolopsis buski 6 Ion vung d6ng bang sdng H6ng, Luan in Ti£n sy nOng nghidp, Trucmg DH ndng nghidp 1, Ha N6i

26 Phan The Vidt, NguySn Thi Ky, Nguydn Thi Le (1977), Giun sdn ky sinh a ddng vat Viit

Nam, Nha xukt ban khoa hoc & ky thuat, Hi Ndi.

29 Gillman R H., Mondal G., Macsud M., Alam K (1982), "Endemic focus o f Fasciolopsis

buski infection in Bangladesh", J Am Med Hyg (31), P 796 - 802.

30 Graczik T K., Alam K., Gillman R H, Mondal G., Ali S (2000), "Development of Fasciolopsis buski (Trematoda; Fasciolidae) in Hyppeutis umbilicalis and Segmentina trocoideus", Parasitol (86), P 324 - 326

31 Idris M., Rahman K M, Muttalib M A (1980), 'The treatment o f Fasciolopsiasis with

nichlosamid and dichlorophen", J Trop Med Hyg (83), P 71 - 74.

32 Lee H H., Shyu L Y., Chen E R (1989), "Experimental control study of Fasciolopsiasis in

Taiwan", Kaohsing J Med, (5), P 335 - 340.

33 Li X (1991), "Food - borne parasitic zoonoses in the people's Republic o f China",

Southeast Asian J Trop Med Public health, (22), P 31 - 46

34 Muttalib M A., Islam N (1975), "Fasciolopsis buski in Bangladesh - A pilot studies", J

Trop Med, Hyg, (78), P 135 - 137

35 Nakagawa K (1921), "On the life cycle of Fasciolopsis buski (Lankester)", Kitasato Arch

Exp Med (4), P 159- 173

36 Shinobu Yoshihara, Nguyen Phuoc Hung, Nguyen Huu Hung, Chau Ba Loc (1998),

"Helminths and Helminthiosis of pigs in Mekong Delta Viet Nam with different to Ascariosis and Fasciolopsis buski infection", Jircas Journal (6), 53 - 58

37 Soulsby L J E (1965), Texbook of veterinary clinical parasitology, Voi I, Oxford press.

38 Soulsby L J E (1976), Helminths, Arthropods and Protozoa of domesticated Animals, London press

39 Waicagul J (1991), "Intestinal fluke infection in Southeast Asia", Southeast Asian J Trop

Med Public Health, (22), P 158 - 162

40 Weng Y L., Zhuang Z I., Zang H P (1989), "Studies on ecology o f Fasciolopsis buski and

control stratery of Fasciolopsiasis in Chines", Zhongguo Ji Sheng Chong Xue Yu Ji, 7 (2),

P 108- 111

BENH SAN LA DA CO

(Param phistom atidosis)

Benh san la da co do nhieu loai san la ky sinh d da co gay ra Truac day, ngudi ta chua xac dinh ro tac hai cua san la da co d gia sue nhai lai Song nhung nam gin day, vdi nhung nghien curu sau han, cac nha khoa hoc da chung minh duac ring, san la da co

ky sinh pho bien va gay nhieu tac hai ddi vdi v it chu Vi vay, hien nay benh san la da co duoc chu y bdi vai tro gay benh dac biet nghiem trong cua san non va ty le chet cao d gia sue bj benh

1 DAC DIEM SINH HOC CUA SAN LA DA CO

1.1 Vj tri cua san la da co trong he thong phan loai dong vat hoc

San la da co nlm trong ldp san la (Trematoda Rudolphi, 1808) thuoc nganh san dep

(Platheminthes Schneider, 1873) Nam 1754, Daubenton da phat hien san la da co diu

tien nhung chua dinh duoc loai Sau do, Falk (1782) da phan loai san la da co dua vao vi tri ky sinh Nam 1790, Schrank va Zeder deu tim ra mot loai san la trong da co huou va

dat ten la Fasciola cervi va Festucaria cervi Nam 1890, Rudolphi doi ten thanh gidng

Amphistoma.

Fischoeder (1901 - 1904) da phan loai nhieu loai mdi, thay ten gidng Amphistoma Rudolphi, 1890 thanh gidng Paramphistomum, cac loai thuoc giong nay dugc xep vao

ho Paramphistomatidae.

Theo Skrjabin va cs (1977), Nguydn Thi Le va cs (1996), vi tri ciia nhung san la da

co ky sinh d gia sue nhai lai Viet Nam trong he thong phan loai dong vat hoc nhu sau:

Nganh Plathelminthes Schneider, 1873

Phan nganh Platodes Leuckart, 1854

Loai Paramphistomum epiclitum (Fischoeder 1904) Loai Paramphistomum gotoi (Fukui, 1922) Loai Paramphistomum gracile (Fischoeder, 1901) Loai Paramphistomum iclukawai (Fukui, 1922)

Loai Paramphistomum liorchis (Fukui, 1922)

Gidng Gigantocotyle Nasmark, 1937

Loai Gigantocotyle bathycotyl (Fischoeder, 1901)

Loai Gigantocotyle siamense (Stiles et Goldberger, 1910)

Gidng Calicophoron Namark, 1937

Loai Calicophoron calicophorum (Fischoeder, 1901)

Loai Calicophoron cauliorchis (Stiles et Goldberger, 1910)

Loai Calicophoron ijimai (Fukui, 1922)

Loai Calicophoron microbothrioides (Price et

McIntosh, 1944)

Loai Calicophoron papillosum (Stiles et Goldberger, 1910)

Gidng Ceylonocotyle Namark, 1937

Loai Ceylonocotyle scoliocoelium (Fischoeder, 1901) Loai Ceylonocotyle dicranocoelium (Fischoeder,

1901)

Loai Ceylonocotyle dinniki (Eduarko, 1982)

Gidng Cotylophoron Stiles et Goldberger, 1910

Loai Cotylophoron cotylophorum (Fischoeder, 1901) Loai Cotylophoron indicum (Stiles et Goldberger,

1910)

Gidng Explanatum Namark, 1937

Loai Explanatum explanatum (Creplin, 1847)

Ho Gastrodiscidae, Stiles va Goldberger, 1910

Gidng Homalogaster Poirier, 1882

Loai Homalogasterpaloniae (Poirier, 1882)

Gidng Gastrodiscoides Leiper, 1913

Loai Gastrodiscoides hominis (Leiper, 1913)

Ho Gastrothylacidae Stiles va Goldberger, 1910

Phan ho Gastrothylacinae Stiles va Goldberger, 1910 Gidng Gastrothylax Poirier, 1883

Gidng Carmyerius Stiles va Goldberger, 1910

Gidng Fischoederius Stiles va Goldberger, 1910

1.2 Hinh thai va cau tao cua san Ia da co

Cac san ia thuoc phan bo Paramphistomatata gom nhirng san la co than hinh khoi

choi, mau do hong, dac biet co giac bung rat ldn d cuoi than san, 2 nhanh ruot phat trien manh va keo dai den cudi than, bit km a cudi San co hai tinh hoan xep phia trudc buong triimg hoac co khi d sau buong trimg San la da co lirdng tinh, thu tinh cheo va tu thu tinh

Theo Nguydn Thi Le va cs (1996), Phan Luc (1997), tren be mat co the san la da co thudng co gai phan bd d phan trudc co the, d mat bung gai nhidu hon va ldn hon He tieu hoa, bai tiet, than kinh va he sinh due ciia san la da co co nhirng dac didm sau:

Co quan tieu hoa bat dau tir 16 mieng d day giac mieng, hau, thuc quan, ruot Can thurc an duoc thai ra ngoai qua 16 mieng

Co quan bai tiet cau tao kieu nguyen don than, gom 2 ong chay doc co the va noi vdi nhau tao thanh tui bai tiet chinh md ra d mut sau co thd, m6i ong bai tiet co nhieu nhanh nho, tan ciing co te' bao ngon lira thuc hien chuc nang bai tiet

He than kinh gom vong than kinh hau nam d phia trudc co thd, tir do co cac day than kinh chay doc vd mut trudc va mut sau co the, noi vdi nhau bdi cac cau noi ngang

He sinh due rat phat tridn, chiem phan ldn ca thd, co cau tao phurc tap, co bo phan

sinh due due va cai trdn m6i ca the

Ve cau true vi hinh thai ciia san la da co, trudc nam 1980 chua co tac gia nao nghidn cuu Eduardo S L (1983) da cong bo ket qua nghien cuu ve hinh thai va cau tao giac mieng, hau, thuc quan, gai sinh due va bd mat bieu bi ciia san la da co dudi kinh hien vi dien tir: be mat bieu bi, trdn mieng, phia trong giac bung va hau ciia san la da co co hang tram mau loi (gai thit) co tac dung h6 tro san la da co bam va lay dinh dudng Theo Eduardo S L., cau true vi hinh thai ciia giac bung, mieng, so lugng va sir phan bo gai thit la co sd bo sung cho viec phan loai san la da co

Hinh 72 Mieng cua C calicophoron

(x 150)

Hinh 73 Giac bung ciia C calicophoron

(x 150)

1.3 Thanh phan loai san la da co d gia sue nhai lai

San la da co ky sinh O dong vat nhai lai g6m nhiiu loai thudc ldp Trematoda

Rudolphi, 1808 Trong cac san la ky sinh 6 loai nhai lai, c£c san la thudc ho

Paramphistomatidae duoc coi la quan trong nha't vi s6 luong ldn v i vai tro gay bdnh cua

chung (Phan Luc, 1997).

Theo Trinh Van Thinh (1963), co 7 loai san la ky sinh d da co thudc ho

Cotylophoron cotylophoron, Gastrothylax crumenifer, Fischoederius elongatus, F cobboldi, Carmyerius spatiosus.

Dieu tra thanh ph£n loai san la da co ky sinh 6 gia sue nhai lai Vidt Nam, Drozdz J

va Malczewski A (1967) da phat hien ra 8 giong gom 23 loai ky sinh a trau, b6, dd, ciru.

Nguydn Thi Le va cs (1996) da xac dinh, ngoai cac gidng, loai ma cac tac gia trdn

phat hien, gia sue nhai lai d nude ta con nhidm them 2 gidng: Explanatum Nasmark,

1937 va Homalogaster Poirier, 1882 vdi 13 loai mdi.

Theo ket qua nghidn curu cua Phan Luc va cs (1999), cd 11 loai san la da co ky sinh

d trau, bo cac tinh midn Bac Viet Nam.

Ceylonocotyle

streptocoelium