STEVE INSKEEP, host:
Two disastrous epidemics in Africa, HIV and malaria, overlap. New research shows the two epidemics fuel each other's growth.
NPR's Richard Knox reports that the way the infections interact may help explain why AIDS has spread so explosively in Africa.
RICHARD KNOX: James Kublin was doing malaria research in Malawi when he began to question the conventional wisdom that sexual promiscuity explains why AIDS has spread so fast in southern Africa.
Dr. JAMES KUBLIN (Health Services, University of Washington): It didn't seem that the promiscuity of that society was that much greater than any other society that I had lived in where the explosive spread of HIV had not occurred. The notion that sexual promiscuity is it is just wrong.
KNOX: Kublin, now with the University of Washington, discovered that when people with HIV also get infected with the malaria parasite, the amount of HIV in their blood shoots up sevenfold and stays high for many weeks. He suspected that people with more HIV in their systems might be more likely to transmit it to others. To find out, he went to Kisumu on the shores of Lake Victoria in Kenya.
Kisumu has a lot of malaria, and one of three adults there also has HIV. Kublin and colleagues analyzed data on malaria, HIV, and sexual behavior in Kisumu. Leiv Abu Rada(ph) says they found malaria raised HIV infection rates in Kisumu by 5 percent over the past 20 years.
Mr. LEIV ABU RADA: This translates into 8,500 HIV cases in this town of about 200,000 adults. So this is the impact of malaria on HIV.
KNOX: It works the other way too.
Mr. RADA: Our calculations show that 10 percent of the malaria incidents in Kisumu are actually attributed to HIV, because people who have HIV are more likely to get malaria because of their weak immune system.
KNOX: Those HIV-weakened immune systems account for almost a million extra malaria cases in Kisumu over the past 20 years. The analysis is in this week's Science magazine. Now you might say that a 5 to 10 percent increase in HIV and malaria doesn't sound like much, but it adds up to big numbers. James Whitworth heads international health programs at the Wellcome Trust, a British charity.
Mr. JAMES WHITWORTH (Head of International Science, Wellcome Trust): The sort of absolute size of the interaction between the two infections is quite small. But because both of these infections are so common and so serious, the public health implications of even a small interaction of them magnifying each other is large.
KNOX: It means that across all sub-Saharan Africa malaria may be responsible for tens of thousands of extra HIV infections, and HIV accounts for many millions of additional malaria cases. Experts say the analysis makes a strong case for a coordinated attack on both diseases. People getting treated for HIV should be tested and treated for malaria, and they should get insecticide-treated bed nets to protect them against malaria-infected mosquitoes. Richard Feachem heads the Global Fund to Fight, Aids, TB and Malaria.
Dr. RICHARD FEACHEM (Global Fund to Fight, Aids, TB and Malaria): Effective large-scale interventions against malaria are more than ever needed, and that will also make the task of fighting HIV/AIDS easier.
KNOX: Kublin and company think the negative synergy isn't limited to HIV and malaria. They're studying the way genital herpes and other infections keep the AIDS fires burning.
Richard Knox, NPR News. Transcript provided by NPR, Copyright NPR.
