A cross-sectional study was conducted from April to October 2023 along the downstream of River Nkam in Yabassi locality (Littoral-Cameroon). The objective was to determine parasite fauna, the prevalence, abundance, mean intensity and risk factors of parasitic infections in wild freshwater fishes as for their control during their successful domestication and conservation. A total of 151 fishes comprising 43 Ctenopoma petherici, 31 Clarias jaensis, 21 Parachanna obscura, 25 Chrysichthys nigrodigitatus and 31 Oreochromis niloticus randomly captured from the River Nkam were used for the determination of the parasitological indexes. The results showed an overall high prevalence of multiple infections of 72.85% of all the fish species by five groups of parasites (p<0.0001) namely monogeneans (61.53%), trematodes (18.54%), myxosporeans (19.90%), cestodes (2.83%) and nematodes (8.72%). Besides, the abundance and mean intensity of monogeneans infection were either low or average and not influenced by the fish species. The significance of the effect of the fish sex, size and weight on the infection by monogeneans depended on fish species. Fishes from the Nkam river should be quarantined and treated against parasites before farming.

Clarias camerunensis is a potential catfish for farming in Cameroon. In order to assess the parasitism of its monogeneans as a function of season and standard lengh, a study was conducted from April 2017 to April 2018 in Lép Mōōga stream, of the Nyong river watershed (Southern Cameroon). 179 specimens of C. camerunsis were sampled by angling through 5 consecutive seasons. The Prevalence, density, abundance of adults and larvae of the main Monogenean species as well as the condition coefficient K and gonadosomatic index of the female C. camerunensis were calculated. The prevalence of the adult Quadriacanthus sp. remained equal to or greater than 85% during this study. Its abundance was low and did not show any clear profile pattern; however, its variation peaked during the rainy season. The gonadosomatic index (GSI) and condition factor (K) of female C. camerunensis evolved in parallel and showed that this fish lays three times a year, during the short rainy, the short dry and the long rainy seasons. The profile of Quadriacanthus sp. larvae showed that this monogenean breeds all year with two peaks during the short rainy season (when the female hosts lay and are weak fry also are in the environment), and in January when hosts are more concentrated in low water. The physiological condition of the fish gradually improved as they grew, when the parasitic density decreased. To limit monogenean outbreaks in farming, this work recommands that fish caught in the wild should be placed in quarantine and dewormed before being exploited.