2007年VOA标准英语-US Scientists Make Important Discovery in Battl

University scientists in the United States have taken what they say is an important step in the effort to end malaria¹.  At Johns Hopkins Malaria Research Institute, scholars recently identified a sugar in mosquitoes that helps explain, for the first time, the  mechanism² of the malaria parasite³ invasion.  The finding could be a key element for a vaccine⁴ development in the fight against malaria.  Producer Zulima Palacio spoke⁵ with the authors of the research and files this report.  Carol Pearson narrates⁶ it.

Malaria is spread by mosquitoes

"I am removing the males only, because the males are not important to our research work.  Males do not blood feed, they feed on sugar only," says researcher Rhoel Ramos Ding-lasan. He is dissecting⁷ the type of mosquito that transmits the malaria parasite that kills about three million people each year around the world.  Experts report the understanding and control of the malaria parasite is one of the most serious scientific challenges of all time.

This week, scientists at the Johns Hopkins Malaria Research Institute announced they identified a sugar in mosquitoes that the malaria-causing parasite [Plasmodium falciparum] needs.  The sugar is essential in the parasite's movement within the midgut section of a mosquito's body.

"This is the mosquito gut⁸, filled with blood," demonstrates Professor Marcelo Jacobs-Lorena, the senior author of the research.  He says that by stopping the production of that sugar, the parasite dies. "The second step, which was a definite proof, was to -- by genetic¹⁰ means -- interrupt sugar production.  So we infected those impaired¹¹ mosquitoes with the parasite and we found that, indeed, the parasite was unable to traverse the midgut."

But the scientists say it is difficult to treat the mosquitoes in nature.  They suggest a human vaccination¹² with antibodies that would block sugar production in the mosquito.  When a mosquito feeds on human blood, it would ingest the antibody.

The new finding brings scientists one-step closer to developing effective malaria vaccines¹³.

Jacobs-Lorena adds,"The best hope we have is that we have a combination of transmission blocking vaccine that the antibody works in the mosquito stage, combined with infection blocking, so that people are protected."

Now 20 years into his work, Jacobs-Lorena says it will take 10 to 15 more years to find practical applications.  Still, he says this new study -- along with research on mosquito gene⁹ modication -- puts scientists closer every day to eradicate¹⁴ malaria.