Colder-than-normal July sea surface temperatures in the tropical South Atlantic are linked to both increased monsoon rainfall and malaria epidemics in the arid and semi-arid regions of northwest India, including the vast Thar desert, according to Mercedes Pascual and her colleagues, who summarize their findings in a paper to be published online March 3 in the journal Nature Climate Change.
Previous efforts to forecast malaria outbreaks in northwest India have focused largely on monsoon-season rainfall totals as a predictor of the availability of breeding sites for the Anopheles mosquitoes that transmit the disease. That approach provides about a month of lead time before outbreaks occur.
The new forecasting tool should improve public health in the region by increasing warning time, thereby informing decisions about treatment preparedness and other disease-prevention strategies, said Pascual, the Rosemary Grant Collegiate Professor of Ecology and Evolutionary Biology and a Howard Hughes Medical Institute investigator. Planning for indoor insecticide spraying, one widely used control measure, could benefit from the additional lead time, for example.
"The climate link we have uncovered can be used as an indicator of malaria risk," Pascual said. "On the practical side, we hope these findings can be used as part of an early warning system."
After being nearly eradicated in India, malaria re-emerged there in the 1970s. An estimated 9 million malaria cases occur in India annually.
Malaria in its epidemic form occurs primarily on the margins of the geographical distribution of the disease, in places like arid northwest India where environmental conditions are only episodically suitable for sustaining Anopheles mosquitoes.
Motivated by the desire for more accurate prediction of malaria risk at longer lead times, Pascual and her colleagues analyzed epidemiological records of malaria incidence in northwest India and used statistical and computer climate models to test potential links between sea surface temperatures, monsoon rains in northwest India, and malaria epidemics there.
They found that most malaria epidemics in northwest India, which peak in October or November, occur when rainfall in the preceding summer monsoon season equals or exceeds a rainfall threshold presumably required to support the growth of Anopheles mosquitoes.
The researchers looked for a correlation between global sea-surface temperatures and epidemic malaria in northwest India. They identified a broad region in the tropical South Atlantic, west of Africa, where cooler-than-normal sea-surface temperatures are significantly associated with increases in both monsoon rainfall and malaria incidence in northwest India.
July sea-surface temperatures in the tropical South Atlantic proved to be remarkably accurate at predicting malaria outbreaks in northwest India during the following fall. In a retrospective analysis of malaria epidemics in the region between 1985 and 2006, the researchers found that July sea surface temperatures correctly anticipated nine out of 11 epidemic years and 12 out of 15 non-epidemic years.
"For this region of India and for this window of time in recent decades, the tropical South Atlantic appears to play a dominant role on rainfall and, through rainfall, on malaria," Pascual said.
Malaria is caused by the Plasmodium parasite, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver and then infect red blood cells.
Pascual's co-authors on the Nature Climate Change paper are B.A. Cash of the Center for Ocean-Land-Atmosphere Studies, X. Rodó of the Institució Catalana de Recerca i Estudis Avançats and the Institut Català de Ciències del Clima in Spain, J. Ballester of the Institució Catalana de Recerca i Estudis Avançats in Spain, M.J. Bouma of the London School of Hygiene and Tropical Medicine, A. Baeza of the U-M Department of Ecology and Evolutionary Biology, and R. Dhiman of the National Institute of Malaria Research in New Delhi, India.
The work was supported by the National Institute of Malaria Research in New Delhi, U-M's Graham Sustainability Institute, and by grants from the National Oceanic and Atmospheric Administration, the National Science Foundation and NASA. The National Center for Atmospheric Research provided high-performance computing support.
Mercedes Pascual: www.lsa.umich.edu/eeb/directory/faculty/pascual
EDITORS: High-res photos available at www.ns.umich.edu/Releases/2013/Feb13/malaria.html
Jim Erickson | Newswise
Further reports about: > Anopheles > Anopheles mosquitoes > Atlantic mollies > Atmospheric > Climate change > Ecology > Economic Forecast > Malaria > Nature Climate Change > Nature Immunology > blood cell > evolutionary history > monsoon rain > monsoon rainfall > red blood cells > sea surface > sea surface temperature > sea-surface temperature > surface temperature > synthetic biology
Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy