Effects of environmental change on malaria in the Amazon region of Brazil

Malaria is endemic in Brazil, affecting mostly the Amazon states. Whereas 50 years ago good progress was made towards its control, since the opening up of the Amazon region for forestry, agriculture and livestock activities, the disease has rapidly increased in incidence, peaking to >500,000 cases annually in the 1990s. Rondônia state was particularly hard hit, with thousands of new immigrants suffering malaria attacks. It is argued that the environmental change caused by deforestation has favoured the main malaria vector Anopheles darlingi, creating numerous sunlit larval habitats and bringing potential blood hosts in the vicinity of the mosquitoes. The creation of malaria clinics and strengthened control programmes has reduced the malaria situation, but risk is still high, particularly in rural and peri-urban areas where humans and mosquitoes are in close contact. The continuing environmental change, caused mainly by deforestation, is likely to favour the malaria situation in Brazil as it creates new malarial habitats and affects large numbers of non-immune settlers who are attracted to the Amazon region.