LONDON – An increasing number of countries worldwide are making spreading HIV a crime, according to a new report from the International Planned Parenthood Federation.

Health officials fear the trend could undermine gains made in fighting the AIDS pandemic and provoke a surge in cases. Globally, about 33 million people are thought to have HIV and nearly 3 million people are newly infected every year.

"If the law is applied badly, this could set us back and do incredible damage," said Paul de Lay, an AIDS expert at UNAIDS, who was not involved in the report.

De Lay said the laws could result in forced testing and drive the epidemic underground as people hide their HIV status, allowing the virus to spread unnoticed.

In  the U.S., 32 states have laws criminalizing HIV transmission. Experts estimate that thousands of people have been charged across the country with spreading HIV.

Since 2001, 16 people in the United Kingdom have been prosecuted for spreading HIV.

In 2005, a woman in Canada was charged with criminal negligence and aggravated assault for passing HIV while pregnant to her baby.

She did not tell her doctors that she had HIV and did not receive the medications necessary to prevent the virus from infecting her child. She was sentenced to a six-month conditional sentence followed by three years of probation.