Malaria – when we don’t see forest or trees

We can include malaria among the various environmental problems created when humans destroy forests. Yesterday’s Guardian International looked at the problem in the Peruvian Amazon and reported that, “Climate change and deforestation are behind the return of malaria in the Peruvian Amazon. Off-season rain is altering the pattern of mosquito development, leaving puddles containing the lethal larvae in areas where malaria had been nonexistent.” Unfortunately, this forces “the mosquito to move to new areas and spreading the disease to places where people are not aware of the disease, where villagers lack the means to get hold of mosquito nets and preventive medicines, and where health authorities have no presence.”

few-trees-left-standing.jpgSimilarly, Afrane et al., reported that, “Significant increases in net reproductive rate and intrinsic growth rate for mosquitoes in the deforested area suggest that deforestation enhances mosquito reproductive fitness, increasing mosquito population growth potential in the western Kenya highlands.”

Yasuoka and Levins have reviewed “60 examples of changes in anopheline ecology and malaria incidence as a consequence of deforestation and agricultural development.” They found that, “sun preference was significantly associated with an increase in (anopheline) density,” although they did insert the caveat that the changes are complex and not necessarily linked directly with increased malaria incidence. They conclude that, “Because deforestation is a process that cannot be readily controlled for a variety of political and economic reasons, investigations and assessments of possible impacts of future deforestation will be crucial to minimize the ecological degradation caused by human activities and to prevent epidemics of malaria and other vector-borne diseases.

Another challenge of deforestation to malaria control is loss of plants that could provide new treatments for malaria and other diseases. Kayode demonstrates in Ekiti State, Nigeria how botanicals used by local populations for treating malaria are becoming rarer. The problem arises because of a land tenure system that pushes the boundaries of farms into the forests.

As if there were not already enough competition for scarce malaria control funding, such changes in climate and mosquito breeding can make the problem worse. In looking at the economic burden of malaria we talked about the need to integrate malaria control and development planning. Now we can see that environmental management must also be a strong part of that picture.

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