F. gigantica: In bile duct of
ruminants, giraffe, zebra in Bangladesh Africa .
Morphology: 25-75mm. by 12mm. in size. Cephalic cone is not very
distnct. Shoulder are not prominant.
In life cycle intermediate
host aquatic snail Lymnaea aricularia var
rufescens.
Life cycle:
Adult female lay eggs in the bile duct and eggs come out through
feces. In egg develops and hatch in 13-17 days at 26-29°C in presence of moisture. Hatched out miracidium enters the snail
within 1-3 days or die if not find the snail. The miracidium develops to
sporocyst, radia and finally to cercariae which escape from the snail from
36-40 days after infection. The cercariae settle on grass blades or other
plants just below water, cast off tail and form the cyst of about 0.2mm. in
diameter known as metacercariae. Under favorable condition the meta cercaria
remain infective for one year.
Final host become infected after ingestion of metacercariae with
herbage. Metacercariae exsheathes with in one hour and penetrate the intestinal
wall. They migrate through the peritoneal/ abdominal cavity and by 4-6 days of
infection they penetrate the liver capsule and reach the liver. The immature
parasites migrate for 8-10 weeks in the liver parenchyma and by about 10-13
weeks they settle in the bile ducts and reach the maturity. PPP- 10-13 weeks.
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