Echinococcosis (hydatid disease): a review and report of a case of secondary echinococcosis.

Echinococcosis is a disease caused by the larval form of Echinococcus granulosus. The adult worm lives parasitically in the intestine of the definitive host, the dog, wolf and other wild carnivores. The ova, which are passed in the feces, are ingested by grazing animals. The intestinal juices free the ovum from its cuticle and, having entered a capillary, it is carried by the blood stream to the liver or lung, where it develops into a hydatid cyst. Man becomes infected by ingesting contaminated vegetables or drinking contaminated water.In a mature hydatid cyst there may be thousands of scolices and each one of these, if released from the hydatid cyst, may form a new cyst if it is planted in a suitable environment. Hydatid cysts are most commonly found in the liver and the lung, but may occur in other organs.A hepatic cyst may rupture into the peritoneal cavity and produce a hydatidoperitoneum. A pulmonary cyst frequently ruptures into a bronchus and is thus evacuated.The disease is of world-wide distribution. In Canada most of the cases of this disease have occurred among Indians and Eskimos. It is now known that a sylvatic cycle has been established in North America and that it serves as a source of infection of the dog and man.The patient reported herein had spontaneous rupture of a hepatic hydatid cyst, with subsequent development of secondary peritoneal echinococcosis. Repeated laparotomies had to be performed to relieve pressure on or obstruction of various organs. The patient made an uneventful recovery and is again usefully employed. No effective medical treatment for this disease is available.