The life cycle of Anguillicola crassus

Abstract

For some years now the parasitic swim bladder nematode Anguillicola crassus of the European eel Anguilla anguilla L., has been reported from several European countries. The enhre life history of this parasite has recently been elucidated in our laboratory. Young larvae leave the swim bladder of the host via the pneumatic duct and reach the water through the digestive tract. They are ingested by small copepods (Cyclopoida), which act as intermediate hosts. Larvae remain in the hemocoel until the copepods are eaten by the final host, the European eel. Larvae penetrate through the intestinal wall and reach the swim bladder where they develop into adults. When infected copepods are eaten by other small fish, such as carp Cyprinus carpio L. or ide Leuciscus idus L., larvae do not reach the adult stage. However, when larger eels feed on such facultative reservoir hosts, they too become infected.