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http://www.scienceblog.com/cms/performing_monkeys_in_asia_carry_viruses_that_could_jump_species_to_humans_9445

Performing monkeys in Asia carry viruses that could jump species to humans

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.

"The market is a condensed area for mixing species and pathogens,"
explained Dr. Gregory Engel, an attending physician at
Swedish/Providence Hospital in Seattle, Wash., a clinical instructor
of family medicine at the UW, and a co-author on the study. "The
animals may be sick or in bad shape there, and they're mixed with
other animals that potentially could have pathogens, and then they're
put into contact with a dense human population."

In this study, the researchers drew blood from 20 urban performing
macaques in Jakarta, Indonesia, and tested those samples for various
simian viruses. They found that about half of the macaques tested
positive for simian foamy virus (SFV), a primate retrovirus that so
far has not been shown to cause disease in humans, but that has been
detected in other monkey-human interaction settings in Asia. Two of
the monkeys tested positive for simian retrovirus (SRV), which, though
it has been shown to infect humans in a laboratory setting, has yet to
be associated with any disease in humans. However, both SRV and SFV
are retroviruses, which are typically slow-acting in their host, so it
could be many years before physicians know the effects of those virus
exposures.

One monkey tested positive for simian T-cell lymphotropic virus
(STLV), which is believed to be the primate ancestor to the human
version of the virus, HTLV, a known cause of T-cell leukemia in
people. One macaque tested positive for herpes B virus, also known as
CHV-1, which rarely infects humans, but, in the 40 known human cases,
was associated with an 80 percent fatality rate.

The researchers still do not know the prevalence of such simian
viruses across larger urban performing monkey populations in
Indonesia, or elsewhere in Asia. Urban performing monkeys can be found
in India, Pakistan, Thailand, Vietnam, China, Japan and Korea. They
hope to learn more about the risk of primate to human viral
transmission in future studies of owners and their monkeys. However,
they urge people to take precautions around performing monkeys, by
preventing the animals from climbing on them and by keeping food away
from the macaques. Such precautions can help reduce the risk of bites
and scratches from the monkeys.

This study included researchers at Bogor Agricultural University in
Bogor, Indonesia, and the Southwest National Primate Research Center
in San Antonio, Texas. It appears in the December issue of the journal
Tropical Medicine and International Health, published on Dec. 8, 2005.

From University of Washington