Echinococcus granulosus Homepage
    
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Adult Parasite:
The adult worms measure 2 to 7 mm long.
 
Echinococcus granulosus adult (left), Echinococcus
granulosus adults in situ - intestine of dog (right).
Hydatid cyst in human (above)
Schematic illustration of hydatid cyst
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Hosts:
- Dogs, coyotes, wolves and other wild canids (definitive).
- Sheep, horses, camels, pigs, and other ungulates (intermediate).
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Life Cycle:
The sheep ingests an egg. The egg hatches in the small
intestine and the larval tapeworm burrows through the intestinal wall and
travels to the liver via the blood. The hydatid cyst develops in (in order
of likelihood) the liver, lungs, brain or other organ. When the dog eats
the sheep viscera and ingests the hydatid cyst, the protoscolices attach
to the small intestinal wall and the worms begin to form proglottids. Gravid
proglottids, containing the eggs, detach from the end of the worm and spill
their eggs into the lumen of the intestine. The eggs pass out in the feces.
The prepatent period is about 47 days.
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Site in host where adult parasite
is found:
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Diagnostic Stage:
Common Diagnostic Test
Clinical Signs:
- Usually asymptomatic in the dog.
- Clinical signs in the intermediate host depend on where
the hydatid cyst is located and how old (large) it is.
Treatment:
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