Variation in seasonal prevalence and intensity of progenetic metacercariae of Clinostomum complanatum infection in Trichogaster fasciatus fish

A total of 1242 out of 1484 Trichogaster fasciatus fish were found to be infected with metacercarial stage of Clinostomum complanatum where 14,258 parasites were recorded mainly from the peritoneal cavity, gills and viscera during five years of study period. The seasonal variations in prevalence, intensity and abundance of the parasitic infection were assessed. The maximum and minimum values of prevalence of metacercarial infection of C. complanatum in the fish were 92.40% and 70.40% during summer and winter respectively. Similarly, intensity and abundance of the parasite were maximum during summer as compared to winter and rainy seasons. The high prevalence of infection of the parasite during summer may be because of the time of emergence of cercariae in high temperature from snail vector and the environment.