Resistance May Mean Malaria Comeback in US, Europe

July 4, 2002
By Rick Callahan
The Associated Press

Indianapolis, Indiana, USA - Malaria is in the midst of an alarming resurgence in both the developed and developing world, despite its virtual elimination in the US and Europe years ago, scientists say.

That is partly because the most deadly of the four human-infecting malaria parasites, plasmodium falciparum, is becoming increasingly resistant to chloroquine, the first and cheapest line of defense against it.

There are also troubling signs that p falciparum is spreading into new regions of the world, most recently the Peruvian Amazon, even as it reappears in areas where it had been eliminated, said Dr Joseph Vinetz, the chief spokesman for the Infectious Diseases Society of America.

"Malaria continues to thunder angrily along in Africa, and it's getting worse in Southeast Asia and in South America, in large part due to its drug resistance," Vinetz said.

Chloroquine resistance has made treating malaria more difficult and expensive.

Whether that trend has led to more deaths is unclear, said Dr MK Cham, who works with the World Health Organization's "Roll Back Malaria" campaign.

"Yet it's clear that if your tools are not effective, then you're not really addressing the problem, which is the number of people suffering from and dying from malaria," Cham said.

At the same time, the dreaded mosquito that spreads most of the world's malaria cases is growing more resistant to insecticides that once held down its numbers.

Still, scientists report some recent progress in efforts to find a way to stamp out the disease. Earlier this year, researchers from the US and Britain announced they had mapped the genome of p falciparum, the most deadly of the four parasites that infect humans.

And scientists from 12 nations recently completed a rough draft of the genome of the mosquito responsible for spreading nearly all human malaria cases anopheles gambiae.

"This is something completely novel in the sense that it's going to allow us to look across genomes," said Dr Paul Brey, head of the insect biochemistry and molecular biology unit at the Pasteur Institute in Paris. "It won't provide us with the solutions; it will only point the way."

Scientists who once worked painstakingly to parse out potential genetic targets in the parasite now have a slightly easier task.
"In the past we've looked for targets one by one under a single light, looking at one piece at a time. Now we have the whole genome to look at in its entirety under a big light for all types of targets," said Michael Gottlieb, chief of parasitology at the National Institute of Allergy and Infectious Diseases.

"The opportunities have never been greater to control malaria."