Distribution of metacercariae in freshwater crabs in relation to Paragonimus infection of children in Liberia, West Africa.

An explanation was sought for the high prevalence of paragonimiasis in children in Liberia by examining possible modes of human infection from freshwater crabs. The occurrence, frequency of infection, and distribution of metacercariae of Paragonimus uterobilateralis in the freshwater crab Liberonautes latidactylus were studied. The muscles of the cephalothorax and of the legs were found to be the most frequently and most heavily infected parts of the crab. A likely risk of infection of children was considered to be the habit of chewing on, or ingesting in a raw state, the walking legs of infected crabs. Possible contamination of the hands of cooks with metacercariae from the internal organs or haemolymph of infected crabs was thought to be a minor route of infection.