The proportion of men having unprotected sex rose significantly each year from 30 percent in 1996 to 42 percent in 2000, Dr. Julie Dodds from Royal Free and University College Medical School in London and colleagues report.

In the year 2000, one hundred thirty-two of 1206 saliva samples (10.9 percent) tested positive for HIV, and 43 of these infections had not been diagnosed previously.

When asked, 83 percent of the men said they knew their HIV status, but 4 percent were wrong.

Roughly 50 percent of men with diagnosed or undiagnosed HIV infection reported unprotected sex in the preceding year.

In fact, men who tested positive for HIV were significantly more likely to report engaging in unprotected sex with five or more partners, and to report a sexually transmitted infection in the previous year, than HIV-negative men.

The results from these surveys are a "public health concern, in an era when HIV prevalence, antiretroviral resistance, and sexually transmitted infection incidence are increasing," the investigators conclude.

SOURCE: Sexually Transmitted Infections, June 2004.

By EMMANUEL NTAVE, Associated Press Writer

MAPUTO, Mozambique - Nearly two-thirds of companies in Africa surveyed by the World Economic Forum expect HIV/AIDS to have a significant adverse effect on their business, according to a study released Thursday. But few are taking action.

Researchers interviewed 1,620 companies in 22 countries for the study published at the forum's annual Africa Economic Summit in Maputo.

Nearly half, 48 percent, reported reduced productivity and increased absenteeism, while 44 percent experienced increased recruitment and training costs.

While 89 percent of respondents said they were concerned about the impact of the pandemic on their business, and 60 percent envisaged a significant adverse effect, only 12 percent had written policies on the subject.

"Unfortunately, the study also shows African companies are not responding enough," said a statement issued by the forum.

The impact in Africa is so severe the World Bank has warned HIV/AIDS could result in economic collapse in parts of the continent if effective action is not taken to combat the spread of the disease.

"We want to ensure more African countries start tackling HIV/AIDS in their work forces and communities", said Kate Taylor, director of the World Economic Forum's Global Health Initiative.

About 40 million people around the world are infected with HIV, the virus that causes AIDS. Nearly 30 million of them live in Africa, where there are over 8,000 new infections each day.

The positive news, Taylor said, was that when African companies do act against the pandemic, they are generally successful.

The report singled out mining giant Anglo American, among other major companies providing life-prolonging anti-retroviral treatment to their workers.

Most of those on treatment have returned to work, according to the report. The program has also increased awareness among the work force about the disease, reducing stigma and dramatically increasing the number seeking to be tested.

"We are delighted that we can show some success stories and not just present a picture of doom and gloom," Taylor said in the statement. "More needs to be done. But if African business could share its experience and action with business leaders in other, less progressed countries in the developing and developed world, it would be a significant step in the fight against HIV/AIDS."