Perspective Chapter: Echinococcosis – An Updated Review

Abstract

Common Name: Dog Tapeworm. Echinococcus granulosus is most prevalent and causes cystic hydatid disease. Echinococcus multilocularis is uncommon and responsible for alveolar hydatid disease. Hydatid disease is a significant health problem worldwide. It is a zoonosis. Adult worm lives in the small intestine of dog and rarely wolf and fox. Dog is the optimal definitive host. The larval stage (hydatid cyst) is found in herbivorous animal like sheep, goat, cattle. Man is the accidental intermediate host. Echinococcal infection occurs through ingestion of eggs that are passed through the feces of definitive host. After ingestion of eggs, the egg liberates embryo which passes through the intestinal mucosa in the portal circulation. Right lobe of the liver is the commonest site for liver hydatid cyst. The cyst wall consists of pericyst, ectocyst and endocyst. Endocyst or the germinal layer is the site of asexual reproduction giving rise to brood capsule and scolices. Symptoms mainly due to pressure effect. Rarely fatal anaphylaxis may occur due to spontaneous rupture or during surgery. USG and CT is the most valuable imaging technique. Serology is an adjunct to diagnosis. Classification of hydatid cyst by Gharvi et al. into five types based on sonographic analysis. Treatment modalities include chemotherapy, percutaneous treatment and surgery.