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Malaria declines with global warming
02 February 2011
Malaria transmission will not increase because of global warming in the African nation of Burundi according to a statistical analysis by researchers in Austria and Burundi. Writing in the International Journal of Global Warming, the team explains that rising temperatures will lead to lower humidity and rainfall which will shorten the lifespan of mosquitoes carrying malaria.
Statistician and epidemiologist Hermenegilde Nkurunziza of the University of Burundi and statistician Juergen Pilz of the University of Klagenfurt, Austria, analysed data on monthly rainfall, temperature and humidity data as well as monthly malaria morbidity data from Burundi for 1996-2007. Data on monthly malaria morbidity for each province of Burundi were collected from Epidemiology and Statistics (EPISTAT), a department of the Burundi Ministry of Health collecting and storing data on epidemiology all over the country. The researchers used Bayesian Generalised Additive Model (GAM) to process the data and found that although malaria transmission is positively associated with minimum temperature and maximum humidity, increasing temperature in Burundi will not result in increasing malaria transmission.
Malaria is the main public health problem in Burundi with transmission of the disease being strongly influenced by several climatic factors. There are around 2 million clinical cases and more than 15,000 deaths each year. It is responsible for half of hospital deaths among children under 5 years and 40% of consultations in health centres.
Temperature is a significant factor, with higher temperatures reducing the incubation period for the disease. Rainfall influences mosquito populations by increasing the vegetation density and the capacity of larva production and maturation. Higher humidity extends adult mosquito life span to lengths commensurate with increased infection rates.