Groundwater (e.g. from wells and boreholes) represents an important source for water supply for populations in Maroua, Far north Cameroon. Although its consumption is being accentuated by the limited access to potable water, the quality of water from boreholes is unknown by the consumers. This study aimed at assessing the bacteriological quality of groundwater from boreholes in Maroua, in order to determine the impact of anthropogenic pressure and to measure the sanitary risks to which people who use them as drinking water sources are exposed. A total of 18 boreholes were chosen as sampling sites for bimonthly analyses (from October 2016 to January 2017). Microbiological analyses comprised the prevalence of total coliforms (TCs), Escherichia coli and Heterotrophic Aerobic and Mesophilic Bacteria (HAMB). Some physico-chemical parameters including temperature, pH, electrical conductivity, total dissolved solids (TDSs), salinity, dissolved CO 2 were measured to characterize these waters and to determine their influence on the bacterial flora. The results showed that the pH of the water of the 18 boreholes varied from 6.3 to 7.5 CU; the lower value of temperature was 25.9 °C and the higher was 31.2 °C. The values of electrical conductivity, TDSs and Salinity fluctuated from 171.5 to 1910.3 µS/cm, 119.4 to 1331.3 mg/l and 79.2 to 970.3 ppm respectively in the water samples of these boreholes. The concentration of dissolved CO 2 varied from 9.5 to 27.8 mg/l of water. From these results, 72.2% of analysed water samples were contaminated by the total coliforms and E. coli. The water contamination would be the consequence of the proximity of boreholes with latrines and domestic wastes. There is a need to educate the public about the quality of their water sources and the importance of clean and healthy surroundings near water sources and to implement household water treatment to improve the water quality and reduce waterborne diseases.

Treated groundwater is a major source of drinking water but subject to potential contamination of fecal–oral pathogens. To understand ecology of the pathogens in the treated water, this study evaluated survival and growth of Vibrio cholerae and Escherichia coli in the treated groundwater in northern Cameroon. E. coli and V. cholerae O1 were isolated from human feces. Water samples were collected from the following sources: a well, tap water from the Cameroon Water Utilities Company, and mineral and borehole waters sold in Maroua, respectively. These waters were treated by one or more processes, including autoclaving, filtration, chlorination and ozonation and were used for the constitution of microcosms. E. coli and V. cholerae were inoculated into each microcosm at respective concentrations of 50 CFU/10 mL (separately) and 40 CFU/10 mL each (together). All bacterial strains survived in all microcosms were used. The ability to survive and grow varied with the bacterial strain and microcosm (P < 0.05). When inoculated separately into the same type of microcosms, V. cholerae grew faster than E. coli with the latter even showing decrease in concentration in mineral water. When inoculated together, V. cholerae grew faster than E. coli, except in autoclaved well water and filtered and autoclaved well water. Autochthonous ultramicroflora inhibited the growth of E. coli in filtered well water (P < 0.05).

The recurrent cholera outbreaks in north Cameroon suggests the existence of hotspot cholera potential reservoirs including polluted surface waters and groundwater. This study investigated water sources, for contamination with Vibrio cholerae, to highlight their role in disease transmission in the cholera endemic areas of Bibémi (north Cameroon). Risk factors of cholera transmission among households were also assessed. The water quality of 15 water points (1 borehole, 8 wells and 6 surface water points) was assessed through commonly used microbiological tests. Also analysed were physicochemical parameters of the water. Results pointed out unsafe water sources (wells and streams) with total coliforms present in all water samples (13-168 CFU/100mL). However, borehole water was negative for total coliforms (0 CFU/100mL) and was qualified for all domestic uses. The results reported the presence of V. cholerae reservoirs along the mayo-Barka course, a stream which water points digged on the dried-up bed are used as drinking water sources in Bibémi. Wells and borehole were negative to V. cholerae. The physico-chemical characteristics of water varied with sampling points. The pH of the water was acidic for most water points; the lower value of temperature was 28.90 °C and the higher was 31.05 °C. The values of electrical conductivity, TDSs and salinity fluctuated from 136.2 to 1308.0 µS/cm, 68.1 to 652.0 mg/l and 67.8 to 650.0 ppm respectively in the water samples. The mayo-Barka presented the higher level of water mineralization. A survey carried out in the study area showed that the low level of education, poor hygiene, poor management of water sources and the scarcity of sanitation would contribute greatly the appearance and spread of cholera in Bibémi. Considering and improving these risk factors by health authorities would help reduce the incidence of cholera and improve the prevention strategies.

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