ECHINOCOCCOSIS

Species under genus Echinococcus are small tapeworms of carnivores with larval stages known as hydatids proliferating asexually in various mammals including humans.
There were five morphologically distinct species in this genus including:
E. granulosus, E. multilocularis, E. oligarthus, E. vogeli and Echinococcus shiquicus.
It is larval stage of the tape worm Echinococcus granulosus.
It is the most common Echinococcus cause hydatid disease.
Hydatid cysts enlarge slowly and required several years for
development.
The cyst range from (1-15 cm) in diameter but may be larger.
Infections may be asymptomatic until cysts cause noticeable
mass effect.
Signs and symptoms vary according to cyst location, size, type
and numbers.
Infectious agent:
Echinococcus granulosus, a small tapeworm of dogs and other canids.
Occurrence:
All continents except Antarctica depend on close association of humans and infected dogs especially common in grazing countries where dogs eat viscera containing cysts. In endemic regions, human incidence rates for cystic echinococcosis can reach greater than 50 per 100 000 person-years, and prevalence levels as high as 5%–10% may occur in parts of Argentina, Peru, East Africa, Central Asia and China.