Latent period of 53 years in a case of hydatid cyst disease

Hydatid cyst is a worldwide endemic disease of man and animals.¹Multiple species of carnivores can serve as hosts for the tapeworm (Echinococcus granulosus), and a variety of wild and domestic herbivores (eg, moose, elephants, kangaroos, sheep) will develop cysts upon ingestion ofE granulosusova.²The sheep-sheepdog cycle, perpetuated by the custom of permitting dogs to feed on sheep carcasses, constitutes the most significant reservoir of infection in domestic animals, and, through man's association with infected dogs, is probably responsible for the majority of human cases. Most human cases encountered in the United States have occurred in immigrants.³ This report describes a 72-year-old man with hydatid cyst disease whose history suggests that the cysts were at least 53 years old. Despite the extraordinary duration of the infection, the patient was asymptomatic until two months prior to operation. This case illustrates the slow growth of hydatid cysts