for National Geographic News
A deadly synergy between HIV and malaria appears to be fueling the spread of both diseases in Africa, a new study suggests.
The report, in tomorrow's edition of the journal Science, is the first to assess how Africa's increased rates of infection are in part caused by an interaction between the two diseases.
HIV makes people more vulnerable to malaria by weakening their immune systems, the researchers say, and contracting malaria may worsen a patient's pre-existing HIV infection, possibly making it more communicable.
Scientists researched the extent of this interaction by studying disease patterns in 200,000 adults in Kenya (see Kenya map).
The scientists found that within this group, about 5 percent of all HIV infections could be attributed to malaria, and 10 percent of all adult malaria episodes could be attributed to HIV.
Dual infection has caused an estimated 8,500 new HIV cases and nearly a million malaria episodes since 1980, the researchers say.
The study suggests that malaria may be a contributing factor to the HIV/AIDS epidemic in sub-Saharan Africa.
"These are two elephants affecting public health in Africa," said the study's lead author Leith Abu-Raddad of the Fred Hutchinson Cancer Research Center in Seattle.
"Any interaction between them is consequential.
"We can't yet say how many cases of HIV malaria has caused over all of Africa," Abu-Raddad said.
AIDS, the disease caused by HIV, and malaria are two of biggest causes of death in sub-Saharan Africa, killing an estimated four million people a year combined.
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