Patterns of rainfall and malaria in Madhya Pradesh, central India.

Some recent outbreaks of Plasmodium falciparum malaria have been attributed, at least in part, to increases in the intensity and duration of rainfall caused by the El Niño southern oscillation (ENSO), a periodic climatic phenomenon. Since it takes time for unusually heavy rainfall to translate into unusually high densities of the vector mosquitoes, it has been suggested that data on recent rainfall might be used to predict climate-related epidemics of malaria. This possibility was explored by comparing the patterns in the incidence of malaria in (1) Dungaria, a highly malarious village in the central-Indian district of Mandla, and (2) Mandla district as a whole, for the periods 1986-2000 and 1967-2000, respectively, with data on rainfall for the same areas and periods. Unfortunately, no clear relationship was observed between rainfall and malaria incidence, although a major development project to improve water resources in the study area (which resulted in local villages being partially or completely submerged in water) may have masked any significant association. A useful method for predicting which years are going to be high- or low-risk years for malaria epidemics, in the present and other epidemiological settings, remains a future goal.