[Diversity of synanthropic flies and their potential for transmitting diarrheal diseases in Maroua (Far North- Cameroon)]. / Diversité des mouches synanthropes et leur potentiel de transmission des maladies diarrhéïques à Maroua (Extrême-Nord, Cameroun).

INTRODUCTION: synanthropic flies are sometimes involved in the transmission of diarrheal diseases as mechanical vectors of pathogenic bacteria. The purpose of this study was to assess the diversity of synanthropic flies and to determine their potential involvement in the transmission of diarrheal diseases in the city of Maroua. METHODS: fly catching sessions were carried out per season in 12 wards, in five different sites and in three moments of the day, corresponding to the different daily sunshine hours. Multiple keys for the identification of diptera and of microbiological analyzes in the laboratory were used to estimate the biodiversity and the portage of microorganisms by the synanthropic flies. We carried out an ecological and statistical analyses of collected data. RESULTS: eight species of synanthropic flies belonging to four families were identified in the city of Maroua and the distribution of these species varied according to the seasons, sites and moment of the day (p<0.05). Musca domestica and Chrysomya putoria were the most numerous species detected in the sites where the activities of agri-food processing and livestock were intense, notably Hardé, Pont-vert, Doualaré, Kongola and Makabaye. Escherichia coli was more involved than Salmonella spp.in the transmission of diarrheal diseases and the portage of bacteria by synanthropic flies was abundance-dependent. CONCLUSION: the diversity of synanthropic flies varies as a function of anthropogenic activities, season of the year and moment of the day. These flies are important potential mechanical vectors of fecal pathogenic bacteria in Maroua.

Survival and Growth of Vibrio cholerae, Escherichia coli, and Salmonella Spp. in Well Water Used for Drinking Purposes in Garoua (North Cameroon).

The ability of strains of faecal bacteria (Vibrio cholerae, Escherichia coli ATCC 25922, and four strains of Salmonella isolated, resp., from well water, pig, poultry, and human urine in Garoua) to survive or grow in well water microcosms was compared. Water samples were obtained from two wells in Garoua (north Cameroun). Autoclaving at 121°C for 15 min and filtration through 0.2 µm filter were used to make microcosms. Microcosms were constituted of unfiltered-autoclaved, filtered-nonautoclaved, and filtered-autoclaved well waters. Bacterial strains were inoculated at initial cell concentration of 3 Log10CFU/mL. All strains were able to survive/grow in used microcosms, and a maximal concentration of 5.61 Log10CFU/mL was observed. Survival abilities were strain and microcosm dependent. The declines were more pronounced in filtered-nonautoclaved water than in the other microcosms. E. coli and Salmonella sp. (poultry strain) lowered to undetectable levels (<1 Log10CFU/mL) after two days of water storage. V. cholera decreased over time, but surviving cells persisted for longer period in filtered-nonautoclaved water from well W1 (1.91 Log10CFU/mL) and well W2 (2.09 Log10CFU/mL). Competition for nutrients and/or thermolabile antimicrobial substances synthesized by "ultramicrocells" or by the autochthonous bacteria retained by the filter might affect the bacterial survival.