A study released this week finds that the virus that causes AIDS is spreading in New York City at three times the rate in the United States. Health officials say New York has long been the epicenter of the U.S. AIDS epidemic because the city is home to sizable populations considered most at-risk for contracting the virus. Victoria Cavaliere reports from VOA's New York Bureau.

New York City's Department of Health and Human Hygiene said the report is the "most precise estimate yet" of annual infections of the HIV virus in New York City.

The report says in 2006, nearly 4,800 New Yorkers contracted HIV, the virus that causes AIDS. This means there were 72 new infections per 100,000 people. That number is three times higher than the national rate, in which the incidence of new infection is 23 per 100,000 people. Overall, an estimated 100,000 New Yorkers are known to be HIV positive.

Dr. Monica Sweeney, the Health Departments Assistant Commissioner for HIV Prevention and Control, said New York City has long been considered the epicenter of the U.S. epidemic.

"The incidence is higher because the groups that are most impacted are highly represented in New York City: Men who have sex with men, immigrants from certain parts of the world," she said. "They are highly represented here and for that reason we have three times the incidence of the rest of the United States."

The findings in the report are based on a new diagnostic formula created by the Centers for Disease Control and Prevention that determines when people became positive within 180 days of contraction.

City officials stress that because the tool is new, it is not yet possible to determine whether infections in the city have increased or decreased from previous years.

The report found that men who have sex with other men was the group most at risk in 2006, accounting for more than three quarters of new infections. Other high risk groups include intravenous drug users and sex workers.

Dr. Sweeney said city officials and partner programs are devising new methods to try and focus prevention and screening at high-risk populations.

"We are doing additional things to make sure we are reaching the target populations," she said. "One of our new prevention efforts is social network testing, where we take people who are highly impacted - sex workers, men who have sex with men, gay men and Hispanics, and ask people to bring their friends in to be tested. That serves two functions. One is to get people into treatment if they're positive, and the other is to interrupt the epidemic through knowing their status [so they] are not giving it out inadvertently to other people."

Sweeney said New York health officials want to make HIV screening a routine part of care. A pilot program in the Bronx offers free testing and encourages all people to get screened.