L5 Trematodes Acquired by Eating Metacercariae Encysted on Vegetation

They are large flukes parasitizing the bile ducts and intestines of mammals most especially ungulates.

Fasciolidae

The body is broad, leaf-shaped and with spiny tegument.

Fasciolidae

The anterior and ventral suckers are lying close to each other.

Fasciolidae

A pharynx and a short esophagus are present and the intestinal ceca as well as excretory bladder are commonly much branched.

Fasciolidae

Receptaculum seminis is absent

Fasciolidae

The ova have thin shells and operculate.

Fasciolidae

Two most important species of Fasciola:

1. fasciola hepatica

2. fasciola gigantica

fasciola hepatica common name

liver fluke

fasciola gigantica common name

giant liver fluke

fasciola distribution

1. F. hepatica is more widespread and occurs in temperate countries and in some tropical areas

2. F. gigantica occurs in tropical & subtropical areas.

fasciola disease

1. fasciolosis

2. liver fluke

3. liver rot

fasciola snail host

lymnaea

3 forms of fascioliasis

1. acute form

2. subacute form

3. chronic form

acute form

postmortem

chronic form

1. hepatic fibrosis

2. hyperplastic congalitis

less common, results from massive attack by large number of flukes with simultaneous migration.

Acute form

Traumatic hepatitis with extensive destruction of the liver parenchyma and marked hemorrhage. Rupture of liver may occur. Animal may die within few days of onset of clinical signs.

Acute form

enlarge, pale and fliable liver, accumulation of blood stained fluid in peritoneal cavity; fibrinous perintonitis.

Postmortem (acute form)

“Black disease” in sheep caused by Clostridium oedematiens is a complication

Postmortem (acute form)

It is a culmination of infection which never, during the migratory phase of the parasite, achieved serious effects on the liver parenchyma.

A more prolonged form with death occurs in 3-4 months. Sometimes animal survive even with severely damaged liver.

Subacute form

Extensive fibrosis in liver, diffuse fibrinous appearance due to numerous fibriotic tracts. Animal suffers from anorexia, distended abdomen which is painful to the touch.

Subacute form

proliferation of fibrous tissues in an attempt to restore normal architecture. Pericellular and monolobular fibrosis occur as well as fibrosis of the portal canals. Hepatic arteries become thickened and tortuous. Fibrotic tracts subdivide liver into irregular lobules.

hepatic fibrosis (chronic form)

hyperplasia resulting from the presence of adult worms in the bile ducts causing irritation leading to fibrosis of lamina propria of bile ducts and surrounding tissues. Eggs trapped in smaller ducts induce further fibrosis leading to formation of granulomatous reactions. Walls of duct eventually become calcified resembling a clay pipe thus the term ‘pipe stem liver”.

hyperplastic colangitis (chronic form)

fasciola chemical pathology

1. anemia due to loss of blood and iron deficiency

2. marked changes in plasma protein concentration, hyperproteinemia, hyperglobulinemia

clinical signs fasciola

1. Acute case- blood discharge from body openings, animal dies suddenly

2. Chronic case – anemia, lack of vigor, diminished appetite, pale mucous membrane, edema including intermandibular edema (“bottle jaw”), dry brittle skin, emaciation, diarrhea and constipation. Sporadic human cases of fasciolosis have been reported.

fasciola diagnosis

finding eggs on feces

occurs in marshbuck

Fasciola tragelaphi

occurs in elephant

Fasciola jacksoni

occurs in hippopotamus

Fasciola nyanzae

occurs in liver (rarely in lungs) of cattle, horse, sheep, pigs and wild ruminants (Cervidae)

Fascioloides magna

occurs in the small intestine of man and pig

Fasciolopsis buski

Fasciolopsis buski

Fasciolopsis buski

Members collectively and commonly called “amphistomes’

PARAMPHISTOMOIDEA

Sometimes also called “conical” or ‘ stomach” flukes

PARAMPHISTOMOIDEA

Thick fleshy cylindrical flukes

PARAMPHISTOMOIDEA

Calicophoron

Family Paramphistomidae (in ruminants)

Cotylophoron

Family Paramphistomidae (in ruminants)

Gigantocotyle

Family Paramphistomidae (in ruminants)

Paramphistomum

Family Paramphistomidae (in ruminants)

Explanatum

Family Paramphistomidae (in ruminants)

Ortocoelium

Family Paramphistomidae (in ruminants)

Fischoederius

Family Gastrothylacidae ( in ruminants)

Carmyerius

Family Gastrothylacidae ( in ruminants)

Gastrothylax

Family Gastrothylacidae ( in ruminants)

Velasquezotrema

Family Gastrothylacidae ( in ruminants)

Family Gastrodiscidae in equine

Gastrodiscus

Family Gastrodiscidae in man and monkeys

Gastrodiscoides

Family Gastrodiscidae in bovine

Homalogaster