Archive for Thursday, October 3, 2002

New gene maps may help scientists combat malaria

October 3, 2002


— Researchers have mapped the genes of the parasite that causes malaria and the mosquito that spreads it, breakthroughs that may lead to better insecticides and repellents against the insect and new ways to combat the disease. The ancient scourge kills almost 3 million people a year.

The double triumph pumps hope into a worldwide effort against malaria in an age when the disease is gaining strength in Africa. Up to 1,800 African children under 5 die each day of its shivering chills and brutal fever.

In parallel efforts that involved more than 160 researchers in 10 countries, scientists mapped the genes for Plasmodium falciparum, the deadliest form of malaria, and for Anopheles gambiae, a mosquito that prefers human prey and spreads malaria to millions with its bloodsucking bite.

The British journal Nature published the complete genetic sequence of P. falciparum. The mosquito genome is being published by the American journal Science. The achievement was announced Wednesday in news conferences in London and in Washington.

"This is an extraordinary moment in the history of science," said Carlos Morel of the World Health Organization. "At last, the enormous power of modern technology is penetrating the mysteries of an ancient disease ... which continues to kill millions."

New drugs are desperately needed, said Stephen Hoffman, a co-author of the study who was a researcher at the Naval Medical Research Center in Silver Spring, Md.

Hoffman said all of the major drugs now in use are very old and their effectiveness is fading rapidly. "The drugs that we use to treat malaria were introduced 50 to 2,000 years ago," he said.

He said German researchers already are developing a drug they first tested after spotting a genetic vulnerability in one chromosome of the parasite.

Frank H. Collins, a mosquito expert at Notre Dame University, said studies of the Anopheles gambiae genome have revealed genes that may explain why the mosquitoes favor humans beings above all other prey.

He said genes linked to the insect's sense of smell may be exploited to develop new repellants, while other genes may lead to novel insecticides.

Studies show malaria is becoming increasingly resistant to chloroquine, a drug that has held the line on the disease for decades. At the same time, the mosquito has become tougher to control with current insecticides.

The advances also come in an era when some experts fear a warming climate will let the resistant malaria parasite move into areas where it has been rare or unknown. Officials said malaria, though of a different strain, was detected in both humans and mosquitoes in Virginia recently, the first time in two decades that a wild reservoir of malaria has been found in this country.

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