Positive Environment News

Scientists question climate change, malaria link

Date: 13-Dec-02
Country: UK
Author: Patricia Reaney

Cases of the mosquito-borne disease that kills about 3,000 people a day around the world have surged in parts of the region during recent decades.

Earlier research had suggest the upsurge was due to drug resistance and population growth, and not global warming.

But scientists in the United States and Britain say it may not be just a coincidence that the rise in malaria parallels East African warming trends.

"We're not trying to say we have convincing and conclusive proof that climate change is causing malaria but equally we don't agree with the previous authors," Professor Mike Hulme, a climatologist at the University of East Anglia in England, said in an interview.

"We want to keep the door open that climate change might be causing the malaria increase."


Hulme and medical epidemiologist Dr Jonathan Patz, of the Johns Hopkins Bloomberg School of Public Health in Maryland, who published their findings in the science journal Nature, said the data used in the previous research is not precise enough to rule out a link.

In an earlier study, Simon Hay of Oxford University and his colleagues concluded that the temperature had not altered significantly enough during the past century to explain the surge in malaria in some areas of East Africa.

"In principle there could well be a connection between a warming of climate and an extension of malaria incidence in a population," said Hulme.

"At the moment we can't rule it out."

Hulme said temperatures have increased 0.15 degrees Celsius (around 0.25 F) per decade from 1970 to 1998 in regions of East Africa.

He called for more research and surveillance to identify exactly what it is that is causing the increase in the disease.

Climate warming is thought to be a main contender because higher temperatures in the highland regions of East Africa could extend the transmission season so more people would be exposed to the malaria parasite.

Malaria is the world's deadliest tropical disease. It infects 300 million to 500 million people a year and kills between one million and 2.7 million. Most are African children.

Although anti-malaria drugs are available, the malaria parasite has developed resistance to many treatments. Mosquitoes which carry the parasite are becoming resistant to some pesticides, so finding a malaria vaccine is a top public health priority.

Scientists believe the recent sequencing of the genetic maps of the malaria parasite and the insect that carries it will speed up the development of new treatments, as well as a vaccine and better pesticides.

© Thomson Reuters 2002 All rights reserved

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