(Agencies)
Updated: 2008-01-31 16:42

We've been exploiting them for years as test animals in our laboratories and more recently as subjects of ecotourism, but now a new study reveals common human viruses are killing endangered great apes.

Scientists investigated chimpanzees hit by five outbreaks of respiratory disease between 1999 and 2006 in Cote d'Ivoire in West Africa. Nearly all the endangered chimps became sick and many died.

All available tissue samples gathered from chimp victims tested positive for one of two germs -- human respiratory syncytial virus (HRSV) or human metapneumovirus (HMPV). These viruses often cause respiratory disease in humans.

"The viruses we found are very common," said researcher Fabian Leendertz, a wildlife epidemiologist at the Robert Koch-Institute and Max Planck Institute for Evolutionary Anthropology in Germany. "Antibody prevalence in humans is almost up to 100 percent, meaning almost everybody has had contact with these viruses" and developed antibodies, naturally, designed to fight the germs.

These cases represent the first confirmed evidence of viruses transmitted directly from humans to wild great apes.

"Virtually all diseases that can harm us can harm the great apes since we share so many genetic and physiologic properties," Leendertz told LiveScience.

There is a long history of diseases spreading from great apes to humans, and perhaps from humans to great apes. Ebola is a widespread threat to gorillas and chimps in Central Africa, and may have spread to humans from people who ate infected animals.

HIV, the virus that causes AIDS, originated from chimps and other primates. Gorillas may have given humans pubic lice, or "the crabs." There have been suspicions that chimps at Gombe Stream National Park in Tanzania contracted polio from humans, Leendertz said.

Human diseases that could attack the great apes include germs "that are easily transmitted, such as respiratory disease or diarrhea-causing pathogens, and also those that persist long in the environment, since this creates a higher chance of transmission," Leendertz said.