Hydatid cyst is commonly seen in: September 2011

Ans. B: Liver The majority of hydatid cysts occur in the liver Echinococcosis/Hydatid disease/Echinococcal disease There are three different forms of echinococcosis found in humans, each of which is caused by the larval stages of different species of the tapeworm of genus Echinococcus. The first of the three and also the most common form found in humans is cystic echinococcosis (also known as unilocular echinococcosis), which is caused by Echinococcus granulosus. The second is alveolar echinococcosis (also known as alveolar colloid of the liver, alveolar hydatid disease, alveolococcosis, multilocular echinococcosis, "small fox tapeworm"), which is caused by Echinococcus multilocularis and The third is polycystic echinococcosis (also known as human polycystic hydatid disease, neotropical echinococcosis), which is caused by Echinococcus vogeli and very rarely, Echinococcus oligahus. Alveolar and polycystic echinococcosis are rarely diagnosed in humans and are not as widespread as cystic echinococcosis Definitive Hosts E. granulosus: dogs and other canidae E. multilocularis: foxes, dogs, other canidae and cats E. vogeli: bush dogs and dogs E. oligahus: wild felids Intermediate Hosts E. granulosus: sheep (optimum intermediate host), goats, swine and other wild herbivores (Man is an accidental host and leads to dead end of life cycle) E. multilocularis: small rodents E. vogeli: rodents E. oligahus: small rodents Liver cyst Majority of hydatid cyst occur in the liver, causing symptoms that may include chronic abdominal discomfo, occasionally with a palpable or visible abdominal mass. Liver cyst tend to occur more on the right side