Effect of Season on Myxosporean Infections in Oreochromis niloticus Linnaeus, 1758 (Cichlidae) at MAPE Dam in Adamawa, Cameroon

In order to contribute to a better understanding of the effect of season on Myxosporean infections so as to elaborate prevention and control strategies, 350 Oreochromis niloticus specimens were sampled from May 2016 to May 2017 from the MAPE dam (Adamawa-Cameroon) and the prevalence of infection was determined after classical examination of fish. A total of 12 species of Myxosporeans belonging to the genus Myxobolus were identified. Irrespective of the parasite species, the prevalence was significantly higher in the dry season (52.94%) than the rainy season (39.59%). Four parasite species occurred mostly during the dry season (Myxobolus brachysporus, M. kainjiae, M. ellipsoides and M. pharyngeus) and eight without seasonality. Male fish were significantly more infected in the dry season (57.78%) than the rainy season (39.53%). On the contrary, season did not significantly influence the prevalence in females. Fish of size 100 mm to 150 mm were significantly more infected in the dry season (68.10%) than the rainy season (44.44%). Parasite species were more prevalent in the organs during the dry season than the rainy season. Whether in the rainy season (47.70%) or in the dry season (29.44%), a significantly higher prevalence of parasites was recorded for the kidneys.