2006年VOA标准英语-Scientists Explore New Approaches to Fight Mala（在线收听）

By Zulima Palacio
Washington, DC
13 December 2006
 
watch Malaria Research report

 
Malaria is spread by mosquitoes
Experts and scientists around the world agree that the fight against malaria will only be won through a combination of approaches ranging from new medications and the final discovery of a vaccine, to the use of mosquito bed nets and residential spraying of insecticide.   The John Hopkins Malaria Research Institute in (the eastern city of) Baltimore, Maryland is working in many of the fronts.  VOA's Melinda Smith narrates for producer Zulima Palicio.

Could a genetically modified mosquito be the key element in the fight against malaria?  If so, it could  be a mosquito genetically altered in this laboratory, so it can no longer carry the deadly parasite which causes malaria.

Dr. George Dimopoulos and his team at the John Hopkins Malaria Research Institute have made great advances in the study of the "Anopheles gambiae", the mosquito responsible for spreading malaria. "The idea is to develop a genetically modified mosquito which can mix with a natural population and this resistant gene will be inherited by the offspring."

Dr. Dimopoulos says researchers now know the complete DNA composition of the mosquito.  And from its 1500 genes, they have identified ten directly connected to malaria.  He says if we could better understand the mosquito's immune system, we could block the parasite in the mosquito, and thus the transmission of malaria.

 
George Dimopoulos
"The research we do is not only going to be used for developing a transgenic mosquito approach but there are other ways… like spread a compound that would kill the parasite in the mosquito and work like an insecticide, but instead of killing the mosquito it would kill the parasite, or we would activate an immune response from the mosquito, to kill the parasite."

But scientists around the world agree that malaria is one of the most difficult illnesses to control; and that the solution will require a combined action.  

Dr. Diane Griffin is the director of the John Hopkins Malaria Research Institute, one of the few research centers that has decided to study nearly every aspect of malaria, from the mosquito's DNA composition to the human immune system. 

She says the solution to malaria will take more than one approach: "The vaccine, a new drug or a new insecticide or a new diagnostic agent, any one of those things are not the answer in themselves.  We really need to tackle the disease in multiple fronts in order to really have an impact on control."

The Johns Hopkins Institute is also trying to create a new, effective and fast system diagnosing the disease.

Dr. Griffin adds, "We know that probably more than half of diagnoses of malaria are incorrect and then when the drugs are used in those individuals, that just increases the opportunity for drug resistance, plus is expensive, the newer drugs being used, artemisinin, are expensive compared to the older drugs.

Scientists have determined malaria proteins appear in the urine.  Researcher David Sullivan says they developed a test very similar to a pregnancy test, in which the patient's urine is used instead of drawing blood. "This is a positive urine test, the top line means that the test is working, it's a control band.  The line towards the bottom shows that it is positive for malaria.  We are still refining this.  We hope to improve this test and make it more accessible over the next year or two."

Dr. Sullivan describes another project he is working on.  "We have quinine and quinidine… these are drugs for the working laboratory."

From a drug library of 2000 approved medications, Dr. Sullivan and his team are trying to see if drugs already in use for other illnesses can be used against malaria.

"Our idea is if we discover a new use for an existing drug, then we could rapidly get into the market.  Recently we found an antihistamine.  One out of about 20-30 antihistamines that we tested, inhibits the malaria parasite and suppresses the malaria infection, so we are cautiously optimistic."

Dr. Griffins says, "Its such a cause of death in children and morbidity in adults. More than a million people a year dying of malaria, is a huge challenge." 

Dr. Griffin says there are more victims of malaria now than ever before.  One reason is an increase in the world's population.  But it is also true that for the last 3000 years the resilient malaria parasite has managed to adapt and survive almost anything that humankind has invented to destroy it.