Some urban performing monkeys in Indonesia are carrying several retroviruses that are capable of infecting people, according to a new study led by University of Washington researchers. The results indicate that contact with performing monkeys, which is common in many Asian countries, could represent a little-known path for viruses to jump the species barrier from monkeys to humans and eventually cause human disease. Performing monkeys are animals that are trained to produce tricks in public.
While scientists have conducted extensive research on primate-to-human viral transmission in Africa, where they believe HIV originated, few have researched this topic in Asia.
"People aren't looking at Asia, and they need to do so, because viruses are emerging on that continent," explained Dr. Lisa Jones-Engel, leader of the study and a research scientist in the Division of International Programs at the UW's Washington National Primate Research Center. "There is a large, diverse population of primates there, and a huge human population in dense urban centers, so there's the potential for viral transmission across the species barrier."
The study's authors are urging more research on the different settings in Asia where people have contact with non-human primates – zoos, animal markets, monkey forests, pet ownership, and urban street performances. Most previous research on viral transmission has focused on bushmeat hunting and consumption, a practice in which local residents hunt wild monkeys for food. HIV, the virus that causes AIDS in humans, is believed to have originated as a primate virus and jumped the species barrier to humans when African bushmeat hunters came into contact with blood from infected animals.
However, in Asia other forms of primate/human contact, among them urban monkey performances, may be more prevalent than bushmeat hunting. Asia has a long history of performing monkeys, and initial studies indicate that the performances can include very close, physical contact between the animals and human spectators – monkeys crawling on people, for instance. Such contact might increase the risk of a bite, scratch, or other interaction that could lead to exposure to monkey body fluids.
"The risk of viral transmission in this context is unclear," said Dr. Michael Schillaci, professor of social sciences at the University of Toronto at Scarborough and lead author on the study. "But the contact here can be very intense."
Also troubling are the animal markets where many performing monkeys are acquired by their trainers. The markets typically bring together many different species of wild monkeys, as well as many other types of animals, in very close, unnatural quarters and unsanitary conditions.