cercaria /sərker″ē·ə/ pl. cercariae [Gk, kerkos, tail] , a minute, wormlike early developmental form of trematode. It develops in a freshwater snail, is released into the water, and swims toward the sun, rising to the surface of the water in the warmest part of the day. Cercariae enter the body of the next host by ingestion, by direct invasion through the skin, or through a cut or other break in the skin. Some cercariae of the genera Schistosoma, Chlonorchis, Paragonimus, Fasciolopsis, and Fasciola are known to infect humans. They encyst and complete their development in various organs of the body. Each species tends to migrate to one organ, such as Fasciola hepatica, which grows to become a liver fluke. See also fluke, schistosomiasis.
