Bio-characterization of Some Free Living Amoebae in the Surface Water of the City of Yaounde: Relationship to Physico-chemical Parameters of the Medium

Abstract

A study was carried in Yaounde to evaluate the level of organic pollution in the surface water and to determine the distribution of pathogenic free living amoeba in the aquatic ecosystem. Six points were selected on the Olezoa and the Abiergue streams of Yaounde for our study. Physico-chemical pollution was carried out by standard methods of assessment. The parameters measured were suspended solids, electric conductivity, pH, TDS, Oxydability, BOD5, COD, humidity, Dissolved Oxygen. The free living amoeba were identified by direct observation on microscope and observation after culture on Non Nutritive Agar (NNA)and Page’s Agar Saline Solution (PAS) which are all enriched with Escherichia coli. The data obtained reveal a high pollution of these urban streams of the Mfoundi River system and presents a high densities of telluric amoebae such as Acanthamoeba (21 Cell./L), Balamuthia (11 Cell./L), Naegleria (6 Cell./L), Vanella (17 Cell./L) and Vermamoeba (5 Cell./L). The sizes vary between 12 to 94 μm for the different forms isolated and identified in our study. The presence of amoeba are significantly correlated with hydrometry, temperature, nitrates suspended solids, COD and BOD₅ (p <0.001). These organisms in water show contamination of the groundwater by wastewater during the study period.