Echinococcus multilocularis hydatid cyst, computer illustration. E. multilocularis is a parasitic tapeworm which causes alveolar echinococcosis. It is a highly lethal helminthic disease in humans which primarily affects the liver and causes a hepatic disorder similar to liver cancer, the infection can metastasize to other organs and in case if left untreated, can be fatal. Humans are infected by ingestion of parasitic eggs excreted by feces of definitive animal host, the eggs hatch in small intestine and release a six-hooked oncosphere, which in turn penetrate intestinal wall, migrate through circulatory system to liver, and develop into a multi-chambered ( multilocular ), thin-walled (alveolar) hydatid cyst which proliferates by outward budding.