疟疾治疗：有新发现也有阻力

Two new medical discoveries are raising hopes of containing malaria - the mosquito-borne parasitic disease that each year infects more than 200 million people and claims an estimated 660 thousand lives. Meantime, the World Health Organization is warning about dire consequences if a drug-resistant form of malaria spreads beyond southeast Asia.

Artemisinin is a drug that has helped cut global malaria deaths by more than 25 percent over the past decade. But now, in parts of Southeast Asia, this drug no longer works. And the World Health Organization's Dr. Shin Young-Soo warns of serious setbacks if drug resistance continues to spread.

"The truth is, that malaria will beat us all unless we do more than what we are doing now, and we do it better," he said.

Controlling malaria involves a range of strategies: using insecticidal bed nets to prevent mosquito bites, spraying insecticides, preventive treatment for children and pregnant women, and controlling or changing mosquitoes, or the malaria parasites they carry.

The World Health Organization says that in the last 10 years, 20 countries have brought the disease under control. At a U.S. congressional hearing, Dr. Mark Dybul executive director of the Global Fund to Fight AIDS, Tuberculosis and Malaria, said the world is on course to end malaria.

"We've had so much success over the last 10 years that you've heard about, that high-transmission areas are becoming much more confined," said Dybul.

Dybul said global efforts have led to better treatment and more effective control of the mosquito that carries the parasite.

Dr. Anthony Fauci, at the US National Institutes of Health, points to promising research that involves introducing a strain of bacteria into the mosquito.

"It's a bacteria that infects the mosquito, and what it does is it interferes with the developmental process that the malaria parasite goes through in the mosquito in its lifecycle," said Fauci.

And once the bacterium is in the mosquito, it's passed down to succeeding generations. The hope is, these malaria-proof mosquitoes eventually will replace those that can carry the parasite.

"Which means, if you can get this out there among populations of mosquitoes in different regions of the world in different countries, it could have a profound effect on the control of malaria," said Fauci.

The true test, of course, will come when mosquitos infected with the bacterium are released into the wild. Dr. Guowu Bian is the Michigan State University scientist who led this research. He spoke to VOA via Skype.

"I hope in a few years, maybe three or four years, our mosquito can go to the field," he said.

Another promising line of research involves manipulating the mosquito's genes. Right now, the anopheles mosquito has no defense against the malaria parasite. If scientists can change its genetic makeup, the mosquito's immune system could repel the organism.

Meanwhile, the clock is ticking as the malaria parasite becomes immune to the world's front-line drug against the disease.