This is the VOA Special English Development Report.
Scientists continue to seek better weapons against malaria. Each year the number of cases is in the hundreds of millions worldwide. Around a million people die, most of them in Africa. Economic losses from the disease amount to an estimated one percent of the African economy each year.
George Dimopoulos is an associate professor at the Johns Hopkins Malaria Research Institute in Baltimore, Maryland.
GEORGE DIMOPOULOS: "42 percent of the earth's population live in areas where malaria transmitting mosquitoes exist. All of these people are in risk of being infected with malaria. The sad thing is that the majority of people that are killed by malaria are children because there immune system is not strong enough to ward off this infection."
Malaria is caused by a parasite called Plasmodium. The organism is injected into people through the bite of infected mosquitoes. Malaria can be treated, but in many areas the parasites have become resistant to different drugs.
George Dimopoulos and his team are studying ways to make mosquitoes resist infection by the parasite. There are hundreds of kinds of mosquitoes in the world. Most do not spread malaria. Some have immune systems that kill Plasmodium.
GEORGE DIMOPOULOS: "We are particularly interested in these type of immune reactions that are responsible for killing the malaria parasite. Because we think once we understand how they work, we could be able to manipulate the mosquito genetically and convert mosquitoes that can transmit malaria into mosquitoes that cannot transmit malaria."
The researchers have developed a way to make genetic changes in the three mosquito species known to spread malaria. The changes cause their systems to attack the parasite, blocking its development. Other researchers are working on ways to spread these genetically modified insects among mosquito populations.
Professor Dimopoulos says there is still a long way to go, but current malaria research is highly promising.
A new vaccine is in final testing. So far it has proven effective at preventing the disease in half of those vaccinated -- which is more than ever before.
And at the Malaria Institute at Macha in Zambia, researchers are developing an easier way to identify malaria. The test uses saliva instead of blood to diagnose the infection.
Current efforts in malaria control are mainly based on the use of insecticide sprays and treated bed nets. But George Dimopoulos says malaria needs to be attacked with drugs, with vaccines, with bed nets -- with whatever researchers can find.
GEORGE DIMOPOULOS: "Malaria needs to be attacked with multiple weapons. There is not one magic bullet to control this disease."
And that's the VOA Special English Development Report, written by June Simms. I'm Steve Ember.
plasmodium: a multinucleate mass of cytoplasm formed by the aggregation of a number of amoeboid cells, as that characteristic of the vegetative phase of the slime molds 瘧原蟲
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（來源：VOA 編輯：陳丹妮）
