Four of the patients with polycystic hydatid disease observed by us reported that they were aware ofthe presence of liver disease in the pacas hunted for food. The viscera of these animals were usually given to domestic dogs. All ofour 7 patients reported contact with dogs that had previously ingested viscera of pacas. Examination of the liver considered to be diseased by one of the patients and removed from a paca killed in the same region (State of Acre, Brazil) from which the human cases originated showed the presence of hydatid cysts. The characteristics of the rostellar hooks of the protoscolex indicated that this was the larval form of Echinococcus vogeli. These observations confirm the participation of pacas in the biological cycle of E. vogeli and the pathway through which man may become an alternative intermediate host of this echinococcus.
Echinococcosis; Polycystic hydatid disease; Echinococcus vogeli