Malaria and climate: sensitivity of malaria potential transmission to climate

Malaria, according to the World Health Organization, is one of the most serious and complex health problems facing humanity in the 20th century. In the past, climatic changes have greatly affected its geography. Its seriousness and complexity are therefore likely to be compounded by an anthropogenic greenhouse effect. The Malaria Potential Occurrence Zone (MOZ) model was designed to calculate first-order estimates of climate change impacts on malaria. MOZ focuses on the climatic determinants of the life cycles of malaria parasites and vectors. It does not take epidemiology into account. MOZ predicts receptivity, or potential transmission, rather than actual occurrence. MOZ indicates that the intensity and the extent of malaria potential transmission significantly change under the climate change scenarios generated by five atmospheric general circulation models. All five simulations reveal an increase in seasonal malaria at the expense of perennial malaria. This is cause for great concern. Indeed, seasonal malaria is most likely to lead to epidemics among unprepared or nonimmune populations. Moreover, climate change may trigger massive migrations of environmental refugees. Such population movements would likely put national and international health infrastructures under severe stress. Today, malaria is a developing country issue but could spread to higher latitudes. The results obtained with MOZ suggest that malaria could become a publichealth problem for developed countries within decades.