Seasonality and histopathology of Trichodina puytoraci Lom, 1962, a parasite of flathead mullet (Mugil cephalus) from Tunisia

Trichodinid Ciliophorans are one of the most common and widely dispersed groups of symbionts as parasites of aquatic invertebrate and vertebrate hosts (VAN AS & BASSON, 1989). The taxonomy of Trichodinids is based on the structure and the appearance of the adhesive disc and number and size of its constituents. All of these features can be revealed only by the silver impregnation technique of Klein (KLEIN, 1958). Consequently, the numerous species identified early without silver techniques are inadequately described (LOM & DYKOVA, 1992). Today, ten genera are described within the family Trichodinidae. The genus Trichodina Ehrenberg, 1838 is the largest of this family; more than 200 species have been described from fish (ASMAT et al., 2005). Trichodinids have During a parasitological survey in Ghar El Melh Lagoon in Tunisia, 108 flathead mullet (Mugil cephalus L., 1758) were investigated for protozoan ectoparasites. Trichodina puytoraci Lom, 1962 infecting the gills of the examined fish were isolated and reported for the first time from this locality. The overall infestation prevalence and mean intensity level were 22.42 % and 70 ± 8.1 trichodinids per fish, respectively. The highest prevalence was observed in spring. The relationship between host’s size and parasite prevalence was significant. The histopathological study revealed that M. cephalus heavily infested by T. puytoraci exhibited serious lesions such as hyperplasia of the epithelial cells, fusion and necrosis of secondary lamellae.