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FAMILY FASCIOLIDAE

• It is large, flate, leaf shape diastome.

• It is found in bile duct and intestine of mammals.

• Eggs are large, operculated and containg embryonic cells and yellowish to yellowish- brown in
colour.

• Contains 3 genus Fasciola, Fasciolopsis, Fascioloides

FASCIOLA HEPATICA

• The species occurs commonly in the bile ducts, gall bladder and
liver of sheep, goat, cattle and buffalo.

• It is restricted to Himalayan region in India (Temperate liver

fluke)

• Horse, ass, mule, pig, rabbit, cat, beaver, elephant, rat and man may
rarely be infected.

• Definitive host: Sheep, goat, cattle, buffalo,man,pig, dog, cat.

• Intermediate host: Lymnea truncatula, L.luteola

• Common name: Temperate liver fluke

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• Distribution: Found in temperature region. In india it is seen in hilly areas.

• It is smaller than F. gigentica and size is 20-50mm x 8-12mm.

FASCIOLA GIGANTICA

• It is the commenest species found in India (Tropical liver fluke/

Indian liver fluke)

• Body measures 20-75 mm in length and 4-13.5 mm in breadth.

• It is large, flattened and leaf-like and the cuticle is spinose.

• The anterior cone is not so prominent

• The mouth opening is surrounded by the oral sucker.

• The ventral sucker is larger than the oral sucker and present near
the anterior end.

• Definitive host: Sheep, goat, cattle, buffalo and man also.

• Intermediate host: Lymnea auricularia/ L.acuminata.

• Common name: Tropical giant liver fluke

• Distribution: Tropical and subtropical countries.

• Mode of transmission: Ingestion of vegetation containig encysted

metacercarie

• The caeca are much branched and the diverticula towards the medial side.

• The two testes are much branched.

• The genital pore is present between the intestinal bifurcation and the ventral sucker.

• The ovary is much branched, pre-testicular and present on the right side of the middle.

• Vitellaria are extensively developed, filling the lateral fields and extending medially as well

DIAGRAM OF LIFE CYCLE

• The unembryonated yellow colour operculated eggs containing few embryonic cells, are passed
out through faeces and deposited in water.

• The eggs hatch in about 15-21 days at optimum temperature (220 C to 260 C).

• After hatching out, miracidium is small, actively swimming in water and may live for up to 24 hrs,
during which period it has to find a suitable as its intermediate host.

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• L. truncatula and Lymnea luteola serve as

the intermediate host for Fasciola
hepatica (Amphibious snail)

• L. auricularia (Aquatic snail) as the

intermediate host for Fasciola gigantica
in india.

• The miracidium can penetrate to the snail,

remove its ciliate covering and develops
to sporocyst (1mm)

• The sporocyst produces a number (5-8) of germ balls,each developing into the next larval stage the
redia (1-3mm long) with characteristic blunt processes at the beginning of the posterior quarter.

• Which in turn produces the next larval stage, the cercariae. (no eye spots, tail length is twice the
body length)

• The cercariae are shed into surrounding water and after leading a short, free life attach to some
piece of vegetation.

• Cercaria sheds its tail and forms the cyst, the completed stage being known as its metacercaria.

• Inside the protective cyst, the metacercaria remains alive for considerable periods of time and, under
favourable conditions, may remain viable for up to 12 months.

• The final or vertebrate host is infected when the metacercariae are ingested along with the
vegetation.

• The metacercaria cyst is dissolved in the host by the action of digestive juices

• the liberated metacercaria makes its way to the duct and the liver usually by penetrating the
intestinal wall.

• Usually, the parasite takes about six days to reach the liver

• The small parasites move around in the tissue of the liver for 4-5 weeks causing extensive damage
and by 7 weeks the begin to enter in the bile duct and finally settling down in the bile duct.

• The parasites grow quickly and start producing eggs in about 8 weeks (Prepatent period) after the
infection.

PATHOGENESIS

The several factore are responsible for the pathogenesis in fasciolosis.

a) The number of metacercariae ingested by animals.

b) The species of animals- The parasites is more pathogenic in sheep than other ruminant.

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c) The age of animals-The young animals are less effective than old animals.

Fasciolosis may be acute, subacute and chronic.

• (1) acute fasioliosis

• (2) sub-acute fascioliosis

• (3) chronic fascioliosis.

ACUTE FASCIOLIOSIS

• It is mainly found in sheep after 4-6 weeks of ingestion.

• This is caused by the immature flukes which migrate extensively in the liver parenchyma.

• As a result, there is extensive damage of the liver parenchyma with

profuse haemorrhages. This damages if also due to the feeding
of hepatic cells by flukes.

• Death of the animals occurs due to internal haemorrhages, in

heavy infection.

• Severe rupture of liver capsule, haemorrhagic tract on liver

surface and fibrinous blood clot are found on liver and in
peritoneal cavity.

• Complication of acute fasciolosis in sheep: Several species of the anaerobic bacillus like
Clostridium perfringens or C.novyi may be present in the normal liver without causing any harm
but they start to multiply rapidly in the infected liver with fasciola, finally causing the ‘black
disease’, in sheep.

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SUB-ACUTE FASCIOLIOSIS

• This is found 8-10 week after infection.

• When young flukes reach the bile ducts where produce cholangitis.

• Other pathognomic leason like haemorrhagic tract, subscapular haemorrhagic, hepatomegaly

etc.

CHRONIC FASCIOLIOSIS

• It is the most common form of the infection in sheep, cattle and other animals.

• It is occurs after 10-12 weeks after infection when adult fluke are developed.

• They cause cholangitis, obstruction of bile duct and fibrosis.

• The main pathogenic effects are anaemia due to loss of blood

@ 0.5ml/fluke/day approximately and hypoalbuminaemia
due to utilization and retention of nitrogen.

• Hypoalbunaemia is also evident due to leakage of protien

through the hyperplasic biliary mucosa and create a
condition is known as “bottle jaw condition”

• A hyperplastic cholangitis is caused by the presence of the adult flukes in the bile ducts.

• In heavy infections, fibrosis and inflammation spread almost to the whole of the liver, the bile
ducts show hypertrophy and calcification and the whole
organ becomes hardened.

• In cattle, the walls of the bile ducts are commonly

calcified and protrude markedly from the surface and are
difficult to cut with a knife.

• They resemble the stem of a clay pipe, giving the

common name of pipe-stem liver to the infection.

• In cattle, some times the parasites are found in other

organs especially lungs, they occur in hazel nut sized cyst containing brownish gelatinous
material in which dead/ calcified parasites can be seen is called hazel nut condition of lung

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CLINICAL SIGNS & SYMPTOMS

In acute condition,

• Infected animal becomes inactive,

• Weakness,
• Lack of appetite,
• Shows distended abdomen,
• Ascites,
• Death
• In acute cases in sheep, the animal dies suddenly, blood stained froth appears at the nostrils and
blood is discharged from anus as in the case of anthrax.
In sub-acute condition
• Pale mucous membrane
• Submendibular oedema
• Enlargement of liver
• Ascitis

Chronic condition

• Stiff gait,

• Loss of appetite,

• Black scouring (Black color diarrhoea)

• ‘Bottle jaw’ due to the presence of watery swellings under the mandibles due to
hypoalbunaemia.

• Anaemia

• Pale mucus membrane

• In cattle, digestive disturbances are more marked.

• Constipation is marked.

• Faecal are passed with difficulty.

• Diarrhea in extreme cases.

Epidemiology

• The snail Lymnea auricularia act as a intermediate host in indian condition.

• This infection occurs in animals grazing on areas with ponds, lakes dams or channels.

• In heavy rainfall areas this disease is most prevalent.

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• Highest prevalence of adult flukes is occurs in wet season like June to October.

• Very low temperature >15C is not good for breeding snail as well as for the development of
parasites.

• They usually prevalent in low lying plain area of tropical and subtropical regions.

DIAGNOSIS

• On the basis of history of animals, clinical symptoms

• Diagnosed by the faecal examination where large, oval

shape, yellowish- yellowish brown coloured
operculated eggs are found in microscopes.

• Plate Eliza and Dot- Eliza for the detection of species

specific antibodies in the serum of infected animals.

TREATMENT

Drugs Host Dose(mg/kg) Efficacy

Triclabendazole Sheep 10 90-100%

(Drug of choice) Cattle 12 100%

Buffalo 24 100%

Oxyclosanide Sheep 15 20% against IF

Cattle 10 90-99% AF

Albendazole Sheep 7.5 50-90% YF

Cattle 15 90-100% MF

Closentel Sheep 10 50-90% YF

Cattle 10 90-100% MF

CONTROL

1) Treatment of infected animals.

2) Control of intermediate host snail:

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Chemical control:

• Copper sulphate 10-35mg/hect

• Sodium pentachlorophenate 5-10 ppm in water

• N-tritylomorpholine 45 kg/680 lt/hect

• Ammonium sulphate or quick lime

• Neem leaf and Eucalyptes leaf powder also mollacicidal effect

Mechanical control

• Collecting of snail in mass and then destroying them with hard object

Biological control

• The duck and frog take young and adult snails as their food

• Plant like Shikakkai, Balanites could be grown vicinity of pounds because their poisonous to
the snails.

Managemental control

• Snail population can be reduced by proper drainages which help to eliminate the snail habitats
and remove the vegetation on which the snail feed and metacercariae are formed.

Managemental practice

• Proper disposal of dung

• The wall of manure pit should be made up of concrete and high enough from the earth

• The grazing of animals in contaminated pasture should be restricted at least for one years.

• Regular deforming of the animals especially nearly summer and in early rainy season with good
anti fasciola drugs

• By providing silage.

4) Control of wild animals which is act as reservoir host

• The deer, antelope etc. which having the common grazing are therefore grazing of wild animals
can be restricted by fencing which will turn also control of fasciolosis

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FASCIOLOPSIS BUSKI

• It is also known as “Giant intestinal fluke”, found in India and subcontinents.

• It is having a zoonotic importance.

• Definitive host: Man and Pig.

• Intermediate host: Snail Gyraulus and Planorbis

• Location: Small intestine

Morphology

• It is large, leaf like thick flukes.

• Size is 25-75mm in length and 8-20mm in width.

• Shoulder is absent.

• Ventral sucker is very much larger than oral sucker.

• Testes are tanden and branched.

• Ovary is anterior to testes and branched.

• The eggs are brown in colour, thin shelled, operculate and size is similar to fasciola

LIFE CYCLE

• Immature, unembryonated eggs are discharged into the intestine and stool.

• In two weeks, eggs become embryonated in water, and after about seven weeks, eggs release
tiny parasitic organisms called miracidia, which invade a suitable snail intermediate host.

• In the snail the parasite undergoes several developmental stages (sporocysts, rediae, and
cercariae).

• The cercariae are released from the snail and encyst as metacercariae on aquatic plants such
as water chestnut, water caltrop, lotus, bamboo, and other edible plants. The mammalian final
host, becomes infected by ingesting metacercariae on the aquatic plants.

• After ingestion, the metacercariae excyst in the duodenum in about three months and attach to
the intestinal wall.

• There they develop into adult flukes (20 to 75 mm by 8 to 20 mm) in approximately 3 months,
attached to the intestinal wall of the mammalian hosts (humans and pigs).

• The adults have a life span of about one year.

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PATHOGENESIS

• The parasites are responsible for inflammation and deep ulceration in small intestine, oedema
and ascites.

• Infected man and pig show the symptoms of diarrhoea,

abdominal pain and ascites.

DIAGNOSIS

• It can be made by finding of eggs in the faeces.

• The Fasciolopsis eggs are brown coloured and thin

shelled with operculum

TREATMENT & CONTROL

TREATMENT

a) Tetrachloroethylene-0.08-0.14 ml/kg b.wt orally.

b) Praziquantel- 5 mg/kg b.wt orally.

c) Carbon tetrachloride- 0.3ml/kg b.wt orally.

CONTROL

a) Treatment of infected man and pig.

b) Control of snail as mentioned.

c) Proper disposal of faeces of man and pig.

d) Eating of nuts and tubers after proper cooking.

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