Abstract

A total number of 200 Lates niloticus were collected alive from several and various localities at Lake Nasser in Aswan governorate, to investigate the prevailing parasites that infect this fish species. All the examined fish were positive for one or more parasites, three trematodes of two families were identified: Diplectanum simile, Diplectanum lacustris and Tylodelphys spp. (recorded for the first time in Lates niloticus representing new host and locality records), two nematodes of two families: Philometra ovata and L3 larvae of Contracaecum spp.(has zoonotic importance), one acanthocephalan parasite: Rhadinorhynchus niloticus, two crustaceans parasites of one family: Ergasilus kandti and Ergasilus latus, while no cestodal infections were recorded at all. The prevalence of trematodes was at 95% meanwhile the nematodes were at 100% in addition to the acanthocephalan parasite was at 24.5% as well, crustaceans parasites were at 69.5%. This study evaluated clinical signs, postmortem examinations, parasitological examinations, seasonal prevalence and histopathological investigations of infected fish in addition to the relation between fish age and parasitism was also described. This study builds on our current understanding of different parasites infecting the wild Lates niloticus and provides novel information on the patterns of the isolated parasites and also serves to reassure the consumers that the musculature (the edible part) of the fish was free from any parasitic infections and safe for human consumption provided that the fish must be eviscerated as soon as possible after being caught and adequately cooked.