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Fasiola
1. Fascioliasis
Liver Fluke, Bottle Jaw, liver rot
SUBMITTED TO
DR G AMBICA
ASST PROFESSOR,
DEPT OF MEDICINE
PREPARED BY
DR THOTA SRINIVAS RAO
RVM/18-41
2. Definition
It is an acute or chronic disease of
ruminants mainly, caused by fasciola
spp.,characterized by sudden death, bottle
jaw, emaciation and chronic digestive
disturbance.
4. Sheep
Apart from Death of the sheep,
• Reduced production and quality of wool
• Reduced lambing percentages
• Poor growth rate of lambs
• Increased costs for replacement stock
Cattle
• Reduced production and quality of milk
• Lower growth rates and lower feed
conversion rates in fattening cattle.
6. o Etiology
– Fasciola hepatica: Mostly found in
temperate and cooler area of high
altitude in tropical and subtropical
countries
– Fasciola gigantica: Mostly in tropical
countries
– Broad Leaf shaped worms large enough
to be visible to the naked eye (adult F.
hepatica measuring 20–30 mm x 13
mm; adult F. gigantica measure 25–75
mm x 12 mm)
8. Predisposing factors
1. Common in low lying swampy areas
2. In areas subjected to frequent
flood-irrigation
3. Stress factors as pregnancy and
parturition
11. Epidemiology
Animal Susceptible:
• It is primary disease of ruminants but may be
affect others as horse, camel, deer, pigs, rabbits,
human, dog and cat
Seasonal incidence:
• Intermediate host snails is Lymnaea spp
• Fasciola hepatica: Lymnaea truncatula
• Fasciola gigantica
– L. auricularia
– L. acuminata & L.rufescens (India & Pakistan)
12. • Snail
– Optimum temperature for breeding: 10 – 28°C
– Increasing in environmental temperature:
Mortality of snail occurs (Infectivity falls)
– Size of snail: Size directly related with release
of Metacercariae
– Moist and warm condition (mud) grow well
– Under unfavorable condition goes to
Hibernation
• Ecology of Lymnea
– Permanent habitat – poorly drained soils,
ditches, area of seepage & spring
– Temporary habitat – Hoof marking of animals
(clay soil)
– pH- slight acid pH favour growth
14. Life cycle
Sporocyst Redia cercaria
Live in
pasture
for upto
6-12m
Ingestion
Larvae free from cyst and penetrate duodenum
and wandering through abdominal cavity into
liver and change to adult after 8-10 w
Prenatal infection may occurs where migrating immature larvae infect fetus
in uterus and adult fluke may be recovered from calves less than 6 w age
15.
16. • The egg production of adult flukes is responsible
for the degree of pasture contamination.
• Fluke survive for many years in the liver of
infected sheep; the adult fluke lays between
20,000 and 50,000 eggs a day, and over a long
period.
• In cattle, the egg production declines as the
animal develops a natural resistance to chronic
infections.
• The fluke eggs are passed in the faeces into wet
areas. Here they hatch, when mean temperatures
increase to above 10°C (mostly from mid
September to May).
17. • In summer, the eggs take approximately 21 days to
develop into miracidia; in the spring and autumn,
hatching can take up to 90 days.
• The larva (miracidium) invades the snail, where it
develops and multiplies.
• One single miracidium hatching from a fluke egg can
produce up to 4000 infective cysts (metacercariae).
• Actively swimming cercariae released from the snail
attach to substrates, especially vegetation. The tail is
shed and the cercaria forms a resistant cyst stage
(metacercaria).
• In the presence of sufficient moisture the
metacercariae will remain alive for many weeks,
depending on the temperature.
• They survive longer at below 20°C; higher
temperatures and desiccation will destroy the
metacercariae in a short time.
18. • The snails, acting as intermediate hosts, produce
eggs throughout the year. These eggs hatch
when the temperature is right.
• There is a marked increase in reproduction from
spring to late autumn.
• Snails may produce 3000 eggs a month and one
generation of snails from egg to egg takes only
about one month under optimum conditions.
• Lymnaea spps survives in dry mud for at least
one year, and tolerates low temperatures.
• The snail can move with and against the water
current for long distances.
19. • The epidemiology of the disease is influenced by
the grazing habits of animals.
• Cattle often graze in the wet marshy areas
favoured by the fluke snail, so the eggs are
deposited in a suitable environment.
• If food is available elsewhere, sheep and goats
prefer to graze away from marshy pastures.
• Long wet seasons are usually associated with a
higher infection rate but sheep are more likely to
ingest large numbers of cysts during dry periods
after a wet season, when the animals are forced
to graze in swampy areas, resulting in heavy
infection.
21. Pathogenesis
• Acute hepatic Fascioliasis in Sheep
– Sudden death due to massive invasion of liver by young
fluke with acute hepatic insufficiency and hemorrhage in
peritoneal cavity
– Morbidity & Mortality High
– 6 – 8 weeks old sheep are highly affected
– Severity of disease is directly related to No. of
metacercariae ingested (10,000)
– Traumatic hepatitis – migration of immature fluke aided
by suckers
– Extensive destruction of liver parenchyma & marked
haemorrhage
– If No. of immature flukes entered in to liver is so high –
rupture of liver capsule - haemorrhage falls into
peritoneal cavity
22. Pathogenesis
• Sub Acute form
– Develop slowly due to mature liver fluke in bile duct
which cause cholangitis, biliary obstruction, destruction
of hepatic tissue, fibrosis and hemorrhagic anemia
– If No. of metacercariae ingested is less (<10,000)
– Liver is covered by migratory tracts – infiltration of
inflammatory cells
– Inflammatory cells mount immune response (not upto
protective level)
– Early fibrosis
– Majority of fluke reaches bile ducts and become mature
fluke – Cholangitis
– Anaerobic condition created by migratory flukes favours
multiplication of Clostridium novyi – Black disease
23. Pathogenesis
• Chronic form
– Most common form (ingestion of few metacercariae)
– Morbidity – 30 % and Mortality – 10 %
25. Clinical signs
• Acute form:
– It is rare in cattle and buffaloes and occurs
in young ruminants (sheep and calves)
especially well fattened one
– Decrease of appetite, dullness and
weakness
– Pale mucous membranes and edema in
conjunctiva, enlargement in liver and
ascites
– Recumbence and sudden death within 48 h
with blood stain discharge passage from
nostril and anus (mimics Anthrax)
26. • Sub Acute / Chronic form:
– It is more prolonged due to ingestion of
few number of cercaria
• Sheep
– Decrease appetite,
loss weight, submandibular
edema (bottle jaw), pale and
icteric mm
– Diarrhea and wool shedding
– Anemia and hepatic
malfunction
27. In Cattle and buffaloes
– Anorexia and reduce growth rate, loss of weight
and milk production
– Chronic diarrhea or faeces may be normal/ hard
– Bottle jaw, jugular pulsation and icteric mm
• Fascioliasis/ Ostertagiasis complex
– Diarrhoea is not feature of fascioliasis unless it
is complicated by the presence
of Ostertagia larva
28. Postmortem lesions
• Acute form
– Blood stained exudate – stained & rule out for
Anthrax
– Liver enlarged in size, pale, friable & fibrinous
clot observed on surface
– Congested, swollen and damaged liver
– While incision extensive - haemorrhage tracts
with immature flukes
– Small liver fluke can be seen on slicing a piece
of liver
– Liver capsule showed perforation with
subcapsular hemorrhage
– If liver capsule is ruptured the blood clots
observed in the abdominal cavity
29. • Chronic form
In Sheep – Liver - Large leaf liver flukes
present in bile duct and protruded above
liver surface
– Calcification of bile ducts wall
– Liver parenchyma is extensively fibrosed
In Cattle - Lungs – Hazel-nut sized cysts
containing brownish gelatinous material in
which a live/dead & calcified flukes are
observed
30. • Diagnosis
– History
– Field diagnosis based on emaciation, diarrhea,
bottle jaw, sudden death and fasciolin (antigen
Fh8) test.
– Postmortem lesion
– Laboratory diagnosis
– Samples: faeces, liver, blood and serum
– Fecal examination by direct and sedimentation
Oval, operculated greenish yellow in color and
embryonic cell well demarcated
31. • Diagnosis
Serum biochemical changes: Hypoproteinemia
due to increase protein leakage into the gut
Hematological changes: PCV, Hb and RBCs may
be decrease with severe normochromic anemia,
and hypochromic anemia in chronic form with
eosinophilia
Histopathology of liver to detect liver
degenerative changes
Slicing a piece of liver thinly and put in water
with shaking then permitting the fluke to settle
to the bottom, naked exam. Showed immature
worms of ¼ inch length
32. Differential diagnosis
• Acute form: all diseases cause
sudden death as anthrax,
enterotoxaemia and acute
pasturellosis
• Chronic form: it is confused with all
affection characterized with anemia
and diarrhea as John's disease,
Paramphistomiasis, intestinal
helminthes and nutritional deficiency
(as copper and cobalt)
34. Immunity & Immunization
• Natural immunity
– Cattle - Reinfection of F. hepatica -
moderate to high immunity
– Sheep - fails to develop protective
immunity
• Active immunity
– Cattle – Three doses of irradiated
metacercariae of F. hepatica
– Age - 6 – 9 months
– Sheep – Not effective
35. Control
• Due to the great biotic potential of
Fasciola hepatica and their
intermediate host snails, only a
continuous and coordinated strategic
application of all available measures
can provide economic control of the
disease.
36. Control
• Control should be on a preventive
rather than a curative basis.
• For effective control:
– use strategic antihelminthic treatment,
to reduce the number of fluke in the
host and the number of fluke eggs in
pasture;
– reduce the number of intermediate host
snails;
– manage fluke-prone areas, to reduce
exposure to infection.
37. Control
1. Treatment of infected animals
2. Hygienic measurements
– Infected pastures should not use for grazing
– Wet pasture or floody areas are avoided
– Regular removing of manure
– Avoid grazing near pond area
– Prevent access of natural water resources –
fencing of water resources
– Provide wholesome water supply at
convenient places
– Drainage of water pools & swampy areas
3. Snail control
4. Prophylactic deworming
38. Snails control
• Physical – Improving drainages
• Chemical - Applying molluscicides
– Copper sulphate - 1 in 1,00,000 solution
for water reservoir
– Copper sulphate powder - 10 – 35 kg /
hectare
• Applied along with sand for easy apply and
Sheep are not allowed to graze until rainfall
occurs
• Biological – rearing of ducks, geese and
frog - infected water sources
39. Deworming schedule
• Deworming schedule for sheep in endemic
areas to reduce pasture contamination
– late April/May – adult sheep – treated for adult
& late immature flukes (Triclabendazole) –
Pre-mansoon
– October – entire flock with triclabendazole /
Closantel – Post mansoon
– January – entire flock drug off mature flukes
(Albendazole)
• In Cattle Every December and May to prevent
pasture contamination on spring and winter
40. OXYCLOZANIDE
Cattle
– 10 to 15 mg / kg
(mature -100%)
Sheep
– mature - 15 to 20
mg / kg &
Immature - 45 mg
/kg
42. TRICLABENDAZOLE
Sheep & Cattle
– 10 mg / kg
– Highly effective against
immature flukes
– Sheep – single dose remove
all stages (over one week
old)
• Cattle – two doses remove
over 4 weeks aged flukes
• The best prevention and
control can be achieved with
triclabendazole, which is
effective against early
immature and adult fluke.
