Los Angeles: Some one million Americans are living with HIV, with about 56,000 new infections reported annually, according to a government report.

Among those infected, 250,000 are unaware that they are carrying the infection, the US Centre for Disease Control and Prevention (CDC) said in a report released on Thursday.

Just over 40 percent of the adult US population has been screened at least once for HIV, said the report.

In September 2006, the CDC recommended that all Americans be offered HIV testing as part of their routine medical care.

Last year, the agency allocated additional funds to test an extra 20 million people, primarily African Americans.

The goal of the increased testing is to identify infections at an earlier stage so people can begin treatment with better results. Late diagnosis increases the likelihood that the infection will develop into more serious illness.

In 2005, 38 percent of those diagnosed with the infections developed full-grown AIDS within a year, the report says.

In addition, an HIV-positive individual who is unaware of the infection is three times more likely to transmit the virus than one who knows his or her status, CDC officials said.

The CDC released the report to coincide with the International AIDS Conference held this week in Mexico City. IANS