Led by University of Washington scientists, the study gives force to the suggestion that Asia, where interaction between people and monkeys is common and widespread, could be an important setting for future primate-to-human viral transmission.

A research article in the journal Emerging Infectious Disease says, though SFV has not been found to cause any human disease to date, it is a slow-acting retrovirus and thus it may take many years before scientists determine the effects of infection.

The report also cautions that SFV may change at the genetic level to giver rise to a new strain of the virus that would affect humans.

It is believed that a similar process occurred with HIV, which probably originated as a virus in non-human primates in Africa.

During the study, the researchers visited several countries in Asia, where they interviewed and tested about 300 people who lived or worked closely with any one of several species of small-bodied monkeys called macaques.

Eight of the participants tested positive for SFV, they said.

One of such persons lived in an urban area in Bangladesh that had a large monkey population, while two other people lived near a monkey temple in Thailand.

The infected population also included a farmer in Thailand who had trained monkeys to help him harvest coconuts.