Abstract

Lemma Abera Hirpo

Lake Zwai is located in the rift valley of Ethiopia. Samples of Oreochromis niloticus were collected monthly between July (2010) to June (2011) using gill nets of various mesh sizes. The results indicated that the major internal parasites recorded belong to genus Clinistomum and Contracaecum including Cestodes larval. The prevalence of the parasite differs from season to season. Hence, the infestation was high during the month July to October (2010) for Contracaecum and Clinostomum where as the frequency of Cestodes larva was high in July to August (2010) and in between May and June (2011). On the average, the prevalence was high during July to October (2010) and in June (2011). In conclusion the parasite could bring zoonotic effect on humans even though there is a specific species. Therefore, further studies should be made for identification of these parasite and other common parasites which might cause production loss in the fishery sector.