NEW DELHI, India -- The virus that causes AIDS is being spread through India's general population mainly by married men, who have unprotected sex with prostitutes, according to a study released Thursday.
About 610,000 Indians contracted HIV last year, increasing the overall number of infected Indians to about 4.5 million, said the study funded by the Bill & Melinda Gates Foundation.
In four of the six most affected states, the virus was contracted by businessmen, men in the service sector and hotel employees, said the study, which used federal and state government data.
"The spread from the high-risk behavior groups to the general populace is another key indicator that HIV/AIDS in India has reached epidemic proportions," the study said.
Sex workers' clients, "particularly married males, act as the bridge groups aiding (the spread) ... into the general population."
The study, citing India's National Aids Control Organization, found that more than 85 percent of India's HIV cases are caused by unsafe sex. Another 3 percent contract it through their mother's milk and another 3 percent by using contaminated syringes.
Last month, the Gates foundation pledged $200 million for an HIV-prevention program in India, which has a population of more than 1 billion.
The study's findings differ from the common perception that promiscuous truck drivers and needle-sharing drug users were spreading HIV.
India has shown positive signs in tackling AIDS, though poor record-keeping by local health officials has made it difficult to determine the precise number of people affected, said Carl Haub of the Washington-based Population Reference Bureau.
"India is doing all the right things," Haub said. "It is a hopeful situation. The problem is the size."
The biggest challenge is reaching out to the 640,000 villages spread across the country's 1.1 million square miles, Haub said.
Also, Indians must be educated about how AIDS spreads to erase myths, including that the disease can be contracted through mosquito bites, he said.