遏制疟疾仍需做得更多

Malaria once afflicted people in nearly every country on the planet. Insecticides and eradication campaigns over the past century have contained this mosquito-borne parasitic disease to fewer than 100 countries. Yet in those mainly tropical countries where malaria is still prevalent, it kills more than 650,000 people each year, most of them children.

For every minute that goes by, a child under five years of age dies of malaria.

Malaria has been diagnosed on every continent, but sub-Saharan Africa is the region most afflicted. Dr. Anthony Fauci, who heads malaria research at the U.S. National Institutes of Health, calls the parasitic disease one of the world's worst killers.

“We’ve made substantial progress in a global community way with malaria because there are several countries that predict that by 2015 they will have substantially -- by more than 50 percent and up to 75 percent -- decreased the incidents of malaria. Having said that as the good news, the sobering news is that we still have 660,000 deaths per year from malaria,” Fauci said.

Multiple strategies have been used to fight malaria. Bed nets treated with insecticide protect against mosquito bites. Those infected are treated with drugs early before their disease turns deadly. Pesticides are sprayed to control mosquito populations.

Researchers, including those at Johns Hopkins School of Public Health in Baltimore, are working on changing the mosquito that transmits the parasite that causes malaria.

"We could stop this [disease] and control the mosquitoes by either eliminating them, which is very difficult to do, or by treating them to make them less effective in carrying the infection," said Dr. Peter Agee, the director of the malaria research program at Johns Hopkins.

Agee says Johns Hopkins has had great success with the mosquito treatment strategy in Zambia, where its researchers are working with an established hospital.

"The burden of disease has been knocked down by 98 percent in a decade. So we've gone from 1,500 children being admitted to the hospital each year to a couple dozen," Agee said.

But the success of the global anti-malaria campaign could also be its weakness, according to Dr. Fauci.

"My concern about even saying there’s good progress is that we have been here before, not only with malaria but with other diseases. When you start to see a down-tick in things, people say, 'Well, we have the process or the disease under control. We can move on to emphasizing other things' -- which would be a really bad mistake," Fauci said.

Fauci notes there is no vaccine yet against malaria; mosquitoes that transmit it are becoming resistant to pesticides; and in some places, the malaria parasite is becoming resistant to the drug that treats it. Complacency and cuts in funding could allow malaria to reestablish itself in areas where it has been reduced or eliminated. And the human stakes are still high: in the time it has taken for this report, three more children have died from malaria.