25th June 2010
Source: Cool Earth
Yet another reason to protect rainforests, a new study shows that malaria is severely exacerbated by even low level deforestation. Analysing 2006 data from 54 Brazilian Amazon health districts, the study shows that malaria - the most prevalent vector-borne disease in the Amazon - increased by 48% in response to only a 4.3% rise in deforestation. The Anopheles darlingi mosquito, which carries malaria and enjoys biting people, thrives in pools of water partially exposed to sunlight.
Utilising high resolution satellite imagery and adjusting for factors such as access to health care, health district size and population growth, the University of Wisconsin-Madison report demonstrates a strong statistical link between deforestation and reported cases of human malaria.
"It appears that deforestation is one of the initial factors that can trigger a malaria epidemic," says report author Sarah Olson. The report also suggests that Anopheles darlingi displaces other non-malarial mosquitos when an area is deforested and the risk of contracting malaria is at its highest some 5 to 10 years after the deforestation occurs.
Earlier studies in neighbouring Peru spotted this link, reporting (American Journal of Tropical Medicine, January 2006) from a Stanford University study that the risk of being bitten by a malarial mosquito was 278 times higher in deforested areas compared to areas with 70% or more forest cover.
Preventing deforestation could significantly reduce the negative health impacts of malaria in tropical forest areas.