[Dynamic Abundance of Oocysts in the Mezam Watershed in Bamenda (Northwest Region, Cameroon)].

Abstract

In order to evaluate the abundance of oocysts in the Mezam watershed in Bamenda, Northwest Region of Cameroon, a study was carried out from January to June 2017. Samples were collected monthly from 13 stations within the watershed. The direct concentration method and the Ziehl-Neelsen technique were employed in the identification of these parasites. The physicochemical analysis showed that the water samples had a neutral pH (7.46±0.46), lowly mineralized (165.61±110.02μS/cm), moderately oxygenated (60.64 ± 17, 25%), present moderate organic pollution (2.85±2.49mg/l KMnO4). KMnO4) and low levels of orthophosphate (1.8±1.88 mg/l PO43-) and nitrates (2.47±5.06 mg/l NO3-). Biological analysis revealed the presence of Cryptosporidium spp. (143.98±203.35 oocysts/l), Isospora belli (88.47 ± 123.19 oocysts/l), Cyclospora cayetanensis (141.31±143.19 oocysts/l) and Sarcocystis hominis (76 ± 111.04 oocysts/l). The highest densities of these parasites were recorded at the Mufueh stream, situated in the periurban area. Meanwhile, the lowest densities were found in the urban area (Formuki, Mankon, Ayaba and Mezam streams). The dry season showed higher densities of oocysts (471.42±216.32 oocysts /l). Statistical analysis revealed a significant correlation (P ≤ 0.05) between the density of the organisms and the physico-chemical parameters such as pH, oxidability, dissolved oxygen and nitrates. Respecting basic hygienic rules as well as treating water before use would reduce the risk of contamination of the population.