for National Geographic News
For the first time, and in a surprise to scientists, chimps have been found infected with what is essentially AIDS, a new study says.
The monkey and ape equivalent of HIV—simian immunodeficiency virus, or SIV—has long been thought to be harmless in the animals, never developing into a lethal AIDS equivalent.
Wild, SIV-positive chimps in Africa, the researchers found, are 10 to 16 times more likely to die in a given year than uninfected chimps—giving conservationists one more worry in the struggle to save already at-risk ape and monkey species.
Past evidence had supported the view that SIV doesn't lead to a lethal condition in apes and monkeys, explained AIDS researcher Daniel Douek of the U.S. National Institute of Allergy and Infectious Diseases.
But the study authors "have now conclusively challenged this notion," said Douek, who was not involved in the new research.
(Related: "HIV-Like Virus Found in Gorillas.")
SIV is considered the source of human immunodeficiency virus, or HIV, the virus that causes AIDS. A mutated form of SIV, HIV is thought to have jumped from chimps to humans, perhaps in the late 1800s.
Disease as Ape-Extinction Threat
The study began in 2004 "because of global worries about disease being a major conservation concern for apes," said study co-author Elizabeth Lonsdorf, a primatologist at the Lincoln Park Zoo in Chicago.
Feces and urine tests pinpointed which living chimps were SIV positive. SIV is spread via bodily fluids, during sexual contact and probably during birth, Lonsdorf said. The virus may also spread through biting and fight wounds, she added—"which will be the topic of further study over the next several years."
At the outset of the study, there was little sense that anything was wrong with the SIV-positive chimps, said Lonsdorf, a former National Geographic Society emerging explorer, who has spent considerable time at Gombe. (The Society owns National Geographic News.)
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