Climate change and malaria

Though there is no evidence showing inter-annual variation in malaria transmission intensities and climatic determinants in the Northeast because of better preventive and treatment measures in place, building stronger health systems is an imperative

Malaria is major public health illness in north-eastern India and the disease's burden is estimated to be enormous. The region receives one of the heaviest rainfalls in the world and is endowed with huge evergreen forest reserve, rich in fauna and flora. Both P. falciparum and P. vivax, the causative parasites occur in abundance but P. falciparum is the predominant infection (the killer parasite).

The relative risk of malaria is ascertained to be high in this part of the country on account of favourable climatic determinants and persistent transmission. In the past couple of decades the region has witnessed unprecedented population explosion and economic activities, and consequent increased anthropogenic activities and rise in temperatures.

Global warming is poised to increase transmission intensities and extend disease distribution range as has been reported in Thar Desert region of western Rajasthan. However, in north-east India (the wetland ecosystem), there is no shred of evidence on record for increased malaria receptivity in the changing climatic scenario. A retrospective analysis of data for the period (1986-2009), based in typical foothill malaria endemic areas of Assam, did not reveal any significant association between inter-annual variation in malaria transmission intensities and climatic determinants, including annualised rainfall and mean temperatures (Dev, V. Parassitologia 51: 101-107, 2009). 

Malarial threat, instead, is gradually receding given the intervention tools in place, including efficacious antimalarial drugs and vector control options—insecticide-treated nets/ long-lasting insecticidal nets preventing mosquito bites. 

What is important to get freedom from malaria is building stronger health systems for increased awareness and disease prevention, focused interventions, sustained logistic supplies and capacity building for delivery in time and place for improved healthcare access for those most at risk.  

Vas Dev is with National Institute of Malaria Research (Field Station), Guwahati, Assam