Malaria Remains Daunting Public Health Challenge | Voice of America - English
The malaria epidemic is one of the greatest public health challenges today. Despite some advances, the disease remains a major killer. A child dies of malaria every 30 seconds, most of them in Africa.
Sciencejournalist Joe Palca, who moderated the event, noted that 15 years ago, thedisease got little attention in the American press. Bycontrast, a database search of just three major U.S. papers in the past threemonths turned up 120 mentions of malaria. "Now,that's not to say that each one of those was a major take-out kind of story,but I think that, at least to me, represents the difference between now and 15years ago ? or at least in a crude way I think it does ? and maybe that willhelp explain why people are actually talking about eradicating malarianow." Completelyeradicating malaria ? like smallpox was eliminated in the 1970s ? istheoretically possible, but for several reasons it's a much more challenginggoal. Forone, says Ripley Ballou of the Bill and Melinda Gates Foundation, there is notjust one malaria parasite. "Thereare two predominant species that cause the vast majority of infections thatafflict humans ? Plasmodium falciparum and Plasmodium vivax, and they are verydifferent parasites.And a tool, avaccine for one will not work for the other. They have different treatmentregimens that are required. And the reality is, we do not have those toolstoday, and that's one of the big areas of ours and others' scienceinvestments." Also,the life cycle of malaria is complex. That's good, because the chain can bebroken anywhere as the parasite moves from mosquito to human. You can killmosquitoes with insecticide or stop them from biting, for example with bednets. But as Ballou points out, efforts at eradication have ultimately failedbecause it's hard to get it right. "Andduring this process, the mosquito became resistant to the insecticides, theparasite became resistant to the drugs, and the resources that were brought tobear in the eradication program were not sustainable," Ballou explained."And I think the combination of those three things led to the failure [ofthe eradication effort] and then the sense that it was hopeless." TheAAAS forum also included Steven Phillips, medical director for oil companyExxonMobil. Africa is a major oil-producing region, and Phillips notes that thecompany has some 4,000 employees there. "And a quick-and-dirty riskassessment showed, surprisingly, that malaria was the number one risk faced byour employees." Dr.Phillips says that in Africa, an estimated 60 to 80 percent of all malariacases are not treated by a doctor or other health professional. And many people ? children, usually ? are getting malaria drugs even though they don't havemalaria, because the disease is hard to diagnose. Phillips says it'scounterproductive to use malaria drugs except to treat malaria. "Otherwiseyou're going to wind up treating people that don't have malaria with drugs thatare going to not only breed resistance, but you're not going to treat the realproblem. And so one of the reasons that one out of five children in Africa donot reach the age of five is because, when they have a fever, they either goundiagnosed or presumptively treated for something that they actually don'thave." Thatmeans a correct diagnosis is important. Traditionally, that involves a trainedlaboratory worker examining a blood sample under a microscope. An alternative,rapid diagnosis test has been developed, costing less than a dollar. Phillipsdescribes it as being something like a home pregnancy kit. "There'sa little finger stick and a drop of blood that's put on to a strip, and thenthere's a colorimetric assay that changes colors that's pretty easy toread." Someexperts say the rapid diagnosis test isn't as good as the traditional,microscope-based diagnosis, and Phillips says the World Health Organizationisn't convinced yet, either. That has limited the test's widespread deployment. Onestrategy that proved to be effective is insecticide-treated bednets. Steven Phillips says his company got directly involved in a novel programto distribute the bed nets in four countries where ExxonMobil operates a totalof 2,000 service stations. "Apregnant mother would go to an antenatal clinic. She'd be given a voucher thatwould give about two-thirds off of a long-lasting bed net. She would thenpresent that voucher to a local service station, and she would have a reliablesupply ? along with health education materials ? from an Exxon servicestation." Thebattle against malaria is important because the stakes are so high, as RipleyBallou of the Gates Foundation points out. "Fivehundred million people around the world are infected with malaria every year,and somewhere between one and three million deaths [occur], most of these inchildren under the age of five. There are places where it has been eliminated,but not very many of them, so we really are talking about a globaldisease."