We noted rivers as the main breeding places of Anopheline mosquitoes in Bashagard district. Previous studies of geographic associations with malaria prevalence have found a positive association with proximity to rivers and increased mosquito density and malaria (Van der et al., 2003; Oesterholt et al., 2006; Zhou et al., 2007). Although rainfall can potentially provide the conditions for breeding of Anopheline mosquitoes and increase the malaria hazard, but in Bashagard district it is usually showery; the soil texture of the area is sandy and porous, and is not able to preserve the rain water on the surface. Therefore, the riverside and riverbank of main and seasonal rivers are the potential breeding places for mosquitoes. The showery rainfall washes the breeding places and will result to decreasing in Anopheline vectors population. We postulated
the negative effect of raining; therefore precipitation layer in calculation for mapping malaria hazard was not included. In parallel
to our finding, Haghdoost et al. (2008) and Salehi et al. (2008) have found the negative effect of rainfall on malaria incidence in
southern Iran, while they reported positive correlation of temperature and relative humidity. The hazard map will help us to identify potential breeding places for malaria vectors.