The seasonality of bacterial quality of water in a tropical developing country (Sierra Leone).

Natural water sources used as drinking-water supplies by rural settlements in Sierra Leone were examined monthly over a one-year period to detect any seasonal variations in bacterial quality. The 37 degrees C colony count, levels of selected faecal indicator bacteria and the incidence of Salmonella spp. were monitored. A seasonality was demonstrated for all the variables, counts generally increasing with the progression of the dry season, culminating in peaks at the transition from dry to wet season. Some complications with respect to the interpretation of counts of faecal indicator bacteria from raw tropical waters are noted.