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
New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University
Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences