Study of the influence of environmental factors on the occurrence of Balantidium coli cysts in an urban aquatic system in Cameroon

Balantidium coli is an enteropathogenic cosmopolitan ciliate which causes balantidiasis in humans. There is a high interest in studying it’s occurrence in developing countries because of the vulnerability of the population to infectious diseases. The present study was carried out in order to characterise the cysts of the parasite and to evaluate the influence of environmental variables on their dispersal in an urban stream which is being exploited by the population to accomplish urban agriculture, industrial and domestic activities. The presence of round (825 ± 610 cysts/L) and oval shaped cysts (246 ± 300 cysts/L), whose size varies between 30 and 75 μm was noted. A canonical correspondence analysis shows that the lowest density of the cysts and a relatively low concentration of the ecological indicators of organic pollution are observed upstream (E1) and down stream (E5). High abundance of cyst of Balantidium coli was observed in stations located along a piggery effluent associated with a major market. The similitude index of Bray-Curtis shows an 84% of resemblance between E2, E4 which are located midstream and very close to a populated urban area. Higher densities of cyst are registered during the short rainy season (207±213 cysts/L).