Haematology and histopathology of Nile tilapia parasitised by Epistylis sp., an emerging pathogen in South America

Abstract

Twenty Nile tilapia (Oreochromis niloticus) parasitised by Epistylis sp. were collected for haematological and histopathological analysis. Fish with >400 zooids showed increase in lymphocyte and decrease in neutrophil population (p<0.05), compared to the less parasitised group (<400). Histopathologic analysis showed that Epistylis sp. induces a chronic inflammatory response in the host, possibly provoked by constant contact with the fish skin.