Echinococcosis, or hydatid disease, is uncommon in this country. In the majority of cases reported the disease was contracted abroad, the patients entering the United States as immigrants. Native cases are rare. Thirty-one cases have been reported with an apparent origin in the United States.1 The disease is more prevalent in the state of Virginia than in other sections of the country, probably due to the high rate of infection in hogs in that state. The incidence of appearance of hydatid disease in this country may increase because of the popularity of travel abroad into countries where it may be endemic.
The disease is caused by the presence of the larval stage of Echinococcus granulosus (Taenia echinococcus), for which man is an intermediate host. The dog is the definitive host, and man acquires his infestation by eating contaminated food or through direct contact with infested dog excreta, thus ingesting