Malaria and Deforestation

Nearly 130 million hectares of forest—an area almost equivalent in size to South Africa—have been lost since 1990[1]. A new study of 67 less-developed, malaria-endemic nations finds a link between deforestation and increasing malaria rates across developing nations[2].

Malaria is an infectious disease tied to environmental conditions, as mosquitoes are the disease vector. Deforestation, lead-author Kelly Austin notes, is not a natural phenomenon, but rather results predominantly from human activitie.

The study builds on evidence that patterns in climate change, deforestation, and other human-induced changes to the natural environment are amplifying malaria transmission. "Human-induced changes to the natural environment can have a powerful impact on malaria rates," she says. Deforestation can impact malaria prevalence by several mechanisms, including increased amounts of sunlight and standing water in some areas. Those factors are favourable for most species of Anopheles mosquitoes which are the key vector of malaria transmission[3].

Results of the study suggest that rural population growth and specialization in agriculture are two key influences on forest loss in developing nations. Deforestation from agriculture comes in part from food that is exported to more-developed countries, Austin notes. "In this way, consumption habits in countries like the U.S. can be linked to malaria rates in developing nations."

Austin thinks that leaving some trees and practicing more shade and mixed cultivation, rather than plantation agriculture which involves clear-cutting forests, could help to mitigate some of the harmful impacts.

[1] Food and Agriculture Organization (FAO): Global Forest Resources Assessment 2015, 2015. See here.
[2] Austin et al: Anthropogenic forest loss and malaria prevalence: a comparative examination of the causes and disease consequences of deforestation in developing nations in AIMS Environmental Science - 2017
[3] Vittor et al: Linking deforestation to malaria in the Amazon: characterization of the breeding habitat of the principal malaria vector, Anopheles darlingi in American Journal of Tropical Medicine and Hygiene - 2009