for National Geographic News
More than a million people die of malaria each year, 90 percent of them in Africa. Seventy percent of the victims are children under the age of five.
Now, after paying relatively scant attention to the disease for decades, the international community is showing renewed resolve to combat malaria.
At the G8 summit in Scotland earlier this month, leaders of the world's richest nations vowed to dramatically boost aid for malaria control in Africa. In the U.S. before the summit, the Bush administration pledged 1.2 billion U.S. dollars in malaria aid over the next five years.
The money is targeted at both preventing and treating malaria, using methods ranging from insecticide-treated mosquito nets to antimalaria drug therapies.
The goal, however, is to develop an effective malaria vaccine. None has yet been found, but several new initiatives are underway. One experimental vaccine, tested last year in Mozambique, proved effective at protecting as much as 50 percent of children against the disease for six months.
"Things have really changed," said Brian Greenwood, director of the Malaria Centre at the London School of Hygiene and Tropical Medicine in England. "The disease has long been ignored, but it is definitely getting more attention."
Most malaria infections in Africa are caused by a parasite called Plasmodium falciparum, which carries the most life-threatening form of the disease. It is transmitted from person to person through the bite of a mosquito. Africa is the home to the most deadly species of mosquito, Anopheles gambiae, which transmits the parasite.
Malaria causes persistent fever, severe pain in the joints, and anemiaa deficiency in red blood cellsbecause the parasites use red blood cells to reproduce.
The disease was essentially wiped out decades ago in temperate regions. The introduction of the cheap, antimalarial drug chloroquine in the 1940s led to a dramatic decrease in malaria in Africa as well.
In the 1970s, however, malaria made a comeback in Africa after the falciparum parasite developed a resistance to chloroquine. Since then, the epidemic has spiraled out of control.
"In Africa the situation has not improved in the last 20 years," Greenwood said. "In some areas it has gotten worse, and that's associated with chloroquine resistance."
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