ABSTRACT

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Lernaea cyprinacea is one of the best known species of the genus, with a wide global distribution, that causes lesions on the skin of fresh water fish fostering secondary infections. The aim of the present study was to record the presence of L. cyprinacea on Cnesterodon decemmaculatus and to study the lethal effect of this copepod on a host species of small size. The specimens were parasitized by post-metamorphic stages of females. The ulcerous lesions rapidly became contaminated with dense Saprolegnia sp. mycelia and they were associated with Epistylis sp., a ciliated peritrichid. Histological examination showed invasion of the visceral mass which exerted mechanical compression on the muscle, kidney, spleen and gonad. Fibrous encapsulation and inflammatory infiltrate were observed as a response. The intense visceral invasion provoked in C. decemmaculatus in the reproductive stages makes the fish potentially susceptible to lethal consequences, with consequent damage at the population level.

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