Caractérisation des formes matures de dissémination des protozoaires et helminthes intestinaux dans le réseau hydrographique de la Mezam (région du nord-ouest, Cameroun) et influence des variables abiotiques

Abstract

(54 Oocysts / L) and Sarcocystis hominis (31 Oocysts / L). It was followed by the class of Rhizopoda who is represented by Entamoeba coli (71 Cysts / L) and Entamoeba histolytica (63 Cysts / L). The cysts of Giardia sp. (65 cysts / L) and Chilomastix mesnili (7 cysts / L) belonging to the class of Flagellates followed; and finally, the class of Ciliate who is represented by the specie of Balantidium coli (42 Cysts / L). The spatiotemporal distribution of enteropathogenic Protozoan showed high densities in the month of March during the rainy season at the Muf-upstream, Ayamiddlestream, Mnk-upstream and Mez-potamon stations; and low densities at Aya-downstream, For-downstream and Muf-middlestream stations. The maturation or sporulation rates of these oocysts are 37.55% and 39.58% respectively for Isospora belli and Cyclospora cayetanens is and are higher in the dry season. Statistical analysis revealed positives correlations between the densities of enteropathogenic Protozoan, sporulated oocysts with suspended solids and dissolved oxygen; and negatives correlations between these parasites and some metallic ions (Ca2+, Mg2+, Cl-, K+, HCO3- and NO3-) (p≤0.05). Concerning the enteropathogenic Helminths, biological analysis allowed the identification and the characterization of 10 species belonging to 3 classes. In descending order of density are the class of Nematoda with Strongyloïdes sp. (141 Larvae / L), Ascaris lumbricoïdes (59 Eggs / L), Enterobius vermicularis (9 Eggs / L), Ancylostoma sp. (2 Eggs / L) and Trichuris trichiura (2 Eggs / L). It was followed by the class of Cestoda with Taenia sp. (30 Eggs / L), Diphyllobothrium latum (25 Eggs / L) and Hymenolepis sp. (11 Eggs / L). The least dominant class is the class of Trematoda represented by Schistosoma haematobium (2 Eggs / L) and Fasciola hepatica (1 Egg / L). The Mnk-downstream, Aya-upstream, Muf-upstream, Muf-middle stream and Mez-potamon stations were the most contaminated with enteropathogenic Helminth eggs and larvae; while Mufdownstream, For-upstream and Mnk-upstream showed low densities of these parasites. The maturation rates are 66.35% for the Ascaris lumbricoïdes specie and 28.48% for Strongyloïdes sp. and are higher during the rainy season, showing the role of humidity in the maturation of Helminths eggs and larvae. The statistical analysis (p≤0.05) shows that Helminths eggs and larvae show negative correlations with temperature, salinity, heavy metals and have great affection with environments that have low or moderate organic pollution and are rich in dissolved oxygen. These results show the bioaccumulation effect of heavy metals by intestinal parasites in the water. Respecting basic hygienic rules as well as treating water before use would reduce the risk of contamination of the population