RESUMO
This work aims to study the effect of some environmental and biological factors on spread encysted metacorcarse [EMC] in catfish [Claris gariepinus] at Assuit, Egypt. Out of 240 African carfish were examined, the total prevalence of encysted metacercarie was 56.3%. The high prevalence was observed in young fish [<300 gm] with prevalence 59.2 and, while the highest infection rate was recorded in lengths [25-35 cm.] at a rate of 62.3%. the maximum infestation rate was appeared In summer [78.3%], while the lowest one was detected in spring [36.7%]. Males had slightly higher prevlance rate [57.5%] than females [54.9%]. Two types of E.M.C were detected in present work: Cynodipiostonum E.M.C. [macroscopic cyts]. Prohemistomum E.M.C. [microscopic cyst]. Cynodipiostonum E.M.C. was detected in muscular tissue only and their prevalence was 2.5%. while Prohemistomum E.M.C. was detected in muscular tissue, liver, kidney and gills of examined fish and their prevalence was 53.8%, 26.2%, 9.2% and 7.5% respectively. Present study reflects the sensitivity of different metacercariae in infection in African catfish the factors tested