for National Geographic News
Scientists who study endangered great apes in Africa may be a mixed blessing—while they may scare off poachers, people also carry with them dangerous diseases, a new study says.
But at the same time human presence deters poachers, acting as a boon to population numbers.
"This shows, in our opinion, that we have a stronger positive effect than ... a negative effect," said senior study author Fabian Leendertz, a wildlife epidemiologist at Robert Koch-Institut in Berlin, Germany.
Between 1999 and 2006 three chimpanzee study groups in Taï National Park in Côte d'Ivoire (Ivory Coast) suffered a total of five outbreaks of respiratory disease. Nearly all of the chimpanzees showed symptoms of illness, and many of them died.
Genetic analysis of the virus cultures collected from the dead chimpanzees revealed that the pathogens were human. "We were a bit shocked because this was the first time that it was ever really proven that an acute disease-causing pathogen has jumped from us to the great apes and caused damage there," Leendertz said.
Tony Goldberg, a veterinarian and disease ecologist at the University of Illinois at Urbana-Champaign, was not involved in the research.
"We've known for a long time that wild apes have suffered epidemics of respiratory disease," he said.
"And for a long time people have suspected that human respiratory viruses were the culprit—but we've never had the smoking gun evidence until now."
The study appeared in a recent issue of the journal Current Biology.
Viruses found in the apes are associated with respiratory disease in human infants and children. As people grow older and develop immunity, they tend to be less and less affected, spreading them as easily as the common cold without any visible symptoms.
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