February 19, 2013, by Alex Kirby
Better prediction will save lives as climate change intensifies
Image: Centers for Disease Control and Prevention
FOR IMMEDIATE RELEASE Researchers say a new method of combining both monthly average temperature changes and those occurring each day can improve the accuracy of forecasting malaria outbreaks. LONDON, 19 February – US scientists have found a way to predict more accurately how temperature is likely to affect both the intensity and the distribution of malaria outbreaks. Their work has potentially far-reaching implications because it will improve scientists‘ ability to map where malaria is likely to occur. Knowing this could help to improve malaria control and mitigation strategies in tropical and sub-tropical regions. This could save many lives as climate change develops. The study, published in Nature Scientific Reports, shows how the current way of measuring the temperature change effects on the biology of mosquitoes and the parasites that cause malaria can lead to both under- and over-estimates of the transmission of the disease. It is estimated to have killed from 660,000 to 1.2 million people in 2010, roughly from 1,800 to 3,300 a day. While increased rainfall can contribute to malaria outbreaks, temperature is also an important factor in its transmission. Recent work has shown that mosquito and parasite biology are influenced not only by average temperature, but also by the extent of the daily temperature variation. The study examines how parasite development within mosquitoes is expected to vary over time and space depending on the daily temperature range in Kenya and across Africa. Under cool conditions, the authors say, the typical approach of using mean monthly temperatures alone to describe the environment in which malaria transmission will occur will underestimate parasite development. In contrast, under warmer conditions, the use of mean temperatures will overestimate development. They write: “These findings have important implications for defining malaria risk. Furthermore, understanding the influence of daily temperature dynamics could provide new insights into ectotherm ecology both now and in response to future climate change” [ectotherms are creatures which regulate their body temperature largely by exchanging heat with their surroundings].
Rainfall or temperature?
Alex Kirby is a former BBC journalist and environment correspondent. He now works with universities, charities and international agencies to improve their media skills, and with journalists in the developing world keen to specialise in environmental reporting.