National and regional impacts of climate change on malaria by 2030
This paper analyses impacts of climate change on malaria transmission at the national and regional level in India, with emphasis on the Himalayan region, northeastern states, the Western Ghats and coastal areas under the aegis of NATCOM II and the up Indian Network for Climate Change Assessment (INCCA). It seeks to elicit the most vulnerable areas of malaria due to climate change and pave the way for identifying remedial measures for addressing the potential threat in the country.
The paper presents a map showing the distribution of different categories of Transmission windows (TWs) under the baseline scenario and projected scenario by 2030. It notes that projections based on temperature alone, and combined temperature and Relative Humidity (RH) differ in the number of months of transmission opening.
It reports that, projections based on temperature reveal introduction of new foci in Jammu and Kashmir, Uttarakhand, increased intensity in Arunachal Pradesh, and increase in the opening of more transmission months in the districts of the Himalayan region, northeastern states and the Western Ghats. The northeastern states are projected to show a rise in transmission intensity. Districts under the Western Ghats are not likely to experience any change by 2030 as all the 28 districts show an opening of TWs for 10–12 months in the baseline as well as projected scenario. But TWs based on both temperature and relative humidity show reduced intensity in the number of open months for transmission in the baseline and a slight increase by 2030. The eastern coastal areas are projected to experience reduction in the number of months open for transmission, which is in effect due to increased temperature cutting off the upper limit of transmission suitability.
The article provides the following recommendations.
- There is a need for a detailed study on the presence of micro-niche particularly in areas like Gujarat and Rajasthan.
- Based on the outputs of open months for malaria transmission, validation is needed at the district level to determine cut-off limits of transmission for temperature, relative humidity and rainfall.
- The study should be expanded to other vector borne diseases in India.
- There is a need for a holistic projection based on not climatic parameters alone, but integrated with socioeconomic intervention measures and immunity of the population.