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

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:
F. gigantica (Linnaeus, 1758): co chieu dai than gap 3 lan chieu rong, “vai” khong
co hoac nhin khong ro ret, nhanh ruot chia toa ra nhieu nhanh ngang.

123


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 c 6 “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
0,13 - 0,145 x 0,07 - 0,09 mm.

F. hepatica

F. gigantica

F. gigantica
Hinh 44. San la Fasciola

124

Tri'cng Fasciola


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,
m6 i 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 vung
nude, 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.

125


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 con
dudng:
- 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.
126


- 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
11 nam.

Hinh 46. Vdng dai phat trien
cua san Fasciola
1. Trung nd thanh Miracidium trong
nude
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 Adolescaria
6. San la gan tri/dng thanh ky sinh
trong ong dan mat

I

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:
Mao 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.

127


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 b6 i nhiem san la gan. vi vay cudng
do nhifem tang len theo tuoi trau, bd.
2. DAC D IEM D ICH T £ HO C BENH 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 td
sau:
- Yeu td thdi tiet, khi hau va mua vu

128

Thai tiet, khi hau cua mot 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
qua thay: trau bd d vung ddng bang nhidm san la gan
du, viing ven bidn va mien nui (binh quan ty le nhidm
viing ddng bang tir 19,6% den 61,3%, viing trung du tir

26 tinh mien Bac Viet Nam, ket

cao nhat, sau dd den vung trung
san d cac viing dieu tra nhu sau:
16,4% den 50,2%, viing ven bien

129


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 m 6 kham la 88 %, vung trung du lk
77,6%.
- 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 tu 6i 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

130


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).

Hinh 48.
1,3. L. viridis

a'

O c k y c h it tr u n g g ia n
2,4. L. swinhoei

5. G. truncatula

131


A/

/

Oc L. viridis thucmg sdng 0 nhung noi nude xam x 2fp, de trimg thanh 6 7 - 1 0 trung,
sau 7 ngay no thanh 6c con. Oc L. swinhoei thucmg s6ng trfti n 6 i d c 6ng ranh, ao, h 6 , de
trumg quanh nam, m 6 i 6 co 60 - 150 trung. Trong didu kidn nhiet d 6 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 d 6ng 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 m 6 i 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

132


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 FASCIOLA
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 ch 6” 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

133


phong xa, ngudi ta da tha'y m 6 i san k f sinh d 6ng dan mat la'y 0,2 ml mau m 6 i ngky.
Nhu vay, neu sue vat nhidm ft san thi vai tro chi£m doat dinh ducmg kh 6ng ro, nhung
neu m 6 i 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

135


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. T 6 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 t 6 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 d 6i 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 0,5
ml/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.

136


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
~
Jit '
'
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.
ScTji la g o #

,

**'•&*. */ttf

Hinh 51. Sdn Id F. gigantica ky sinh d o n g
dan m at cua de

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

137


Bidn d 6i 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
138


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

139


4. CHAN DOAN BENH DO FASCIO 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 thudc
sau:
- 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.

140


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.
Lieu lugng:
Bo: 5 - 6 mg/kgTT.
Trau: 8 - 9 mg/kgTT
De, cuu: 5 - 8 mg/kgTT (the man tfnh: 5 - 6 mg/kgTT, the’ cap ti'nh: 7 - 8 mg/kgTT).
Cho tung ca the uong thuoc, hoac goi thuoc vao la chud'i non, dua sau vao mieng

cho con vat nuot.
- 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 ml/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.
Luang 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

141


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 thu 6c 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 6 de.
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.
142


TAI LI$U THAM KHAO CHl/ONG 7 (B$NH SAN LA GAN)
* Tieng Viet
1. Nguyen Due Ducmg (1995), “Di£u tra tinh hinh nhidm giun san ky sinh duang tieu hoa cua
huou sao va ky thuat phong tri”, Luan van Thac sy khoa hoc n6ng nghiep, Ha Noi, Tr. 10.
2. Pham Van Khue va Phan Luc (1996), Ky sinh trung thu y, Nha xua't ban nong nghiep, Ha
N6i, Tr. 53 - 62.
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
hod ”, Tap chi khoa hoc ky thuat thu y, Tap V, sd 3, Tr. 94 - 98.

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 Dertil 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 tr a n hi e m s an la
gan 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.

143


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
III, s6 1, Tr. 82-86.
17. Trinh Van Thinh (1963), Ky sinh trung thu y, Nha xua't ban nOng th6n, Ha NOi, Tr. 281 292.
18. Trinh Van Thinh, Dd Duang Thai (1978), Cong trinh nghien ciru ky sinh trung o'Viet Nam,
Tap 2: Giun san a d6ng vat nudi, Nha xu£t ban khoa hoc va ky thuat, Ha NOi.
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.

144


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 FASCIOLOPSIS 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.
145


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).
Giac mieng
Mang trc in g _

Lo sinh due

Gidc bung

T ir cung
Tuyen noan hoang

Bu6ng trim g
Ootyp

Tinh hoan

Hinh 60

Hinh 59
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 (D 6 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.
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), D 6

Hinh 61. F. buski
nhuom carmin

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

san d da day va ruot gia.
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

146

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


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:

Sa 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 Miracidium 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).

147