Study Says Malaria Helps Spread HIV

Wednesday, Jan. 31, 2007 Posted: 10:39:37AM PST

WASHINGTON (AP) - Malaria is fueling the spread of AIDS in Africa by boosting the HIV in people's bodies for weeks at a time, says a study that pins down the deadly interplay between the dual scourges.

It's a vicious cycle as people weakened by HIV are, in turn, more vulnerable to malaria.

University of Washington researchers who estimated the impact of the overlapping infections concluded that the interaction could be blamed for thousands of HIV infections and almost a million bouts of malaria over two decades in just one part of Kenya.

The research, published in Friday's edition of the journal Science, highlights the need for a joint attack on both epidemics.

"It's an important paper," said Dr. Anthony Fauci of the National Institutes of Health, the government's leading infectious disease specialist. "We really need to be much more serious about what we do about malaria at the same time we're serious about what we do about HIV."

Anti-malaria programs, such as a $1.2 billion U.S. initiative in its early stages, "assume a much, much greater imperative when you realize not only are you going to have an impact on one disease, but you might impact another disease," Fauci added.

Malaria sickens up to half a billion people annually and kills more than 1 million, mostly young children and mostly in Africa — which also bears the biggest HIV burden. Sub-Saharan Africa is home to 24.7 million HIV-infected people; about 2 million died this year, according to the latest U.N. update.

Scientists long have suspected the two diseases fuel each other. The new study created a mathematical model to figure out just how much they do.

HIV is most easily spread when patients have high virus levels in their blood. A bout of malaria causes a temporary surge — a stunning sevenfold increase — in those levels, said lead researcher Laith Abu-Raddad, a scientist at the University of Washington.

The surge may last six weeks to eight weeks. That is longer than it takes adults in intense malaria areas, where people get the parasitic disease once or twice a year, to recover from a typical bout and feel up to sexual activity again, he said.

Moreover, HIV patients are more susceptible to malaria reinfection because of their weakened immune systems.

Armed with that information, Abu-Raddad turned to Kisumu, Kenya, a region where he found good data tracking HIV and malaria prevalence over decades, and even information on sexual behavior such as average number of partners and volume of sex workers.

In regions where both diseases are common, malaria may be responsible for almost 5 percent of HIV infections, and HIV may be behind 10 percent of malaria episodes. In Kisumu, that translated into 8,500 extra HIV infections and 980,000 extra malaria bouts over two decades, he concluded.

"It's a substantial impact," Abu-Raddad said, adding that it helps to explain HIV's explosive spread across southern Africa.

"We were very surprised" the numbers were so high, added study co-author Dr. James Kublin, an HIV researcher at the Fred Hutchinson Cancer Research Center in Seattle.

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Lauran Neergaard
AP Medical Writer