The tiny African kingdom of Lesotho will launch door-to-door HIV tests to mark World AIDS Day on Thursday, hoping to turn back an epidemic that infects almost one third of the adult population.

“The main aim of the campaign is that all people above the age of 12 years living in Lesotho will know their HIV status by the end of 2007,” the World Health Organisation said in a statement on Tuesday announcing the programme.

Lesotho, a poor mountainous country completely surrounded by South Africa, has seen HIV/AIDS wreak havoc as farmers die, cutting agricultural production, and more and more children must take over as head of household after the death of their parents.

As in much of the rest of Africa, many people remain reluctant to go for HIV tests due to the stigma attached to people who have AIDS in Africa. Such attitudes contribute to widespread ignorance about the virus, allowing it to spread further, doctors say.

The WHO said Lesotho, with a population of about 1.2 million, provided a good test case for reversing this trend because it had a history of mass health interventions.

“Lesotho has a successful history of carrying vaccinations house-to-house. This same approach will be used to offer HIV testing and counselling,” the WHO said.

The tests will be free, but not compulsory, and officials say they hope the door-to-door approach will persuade more people to find out if they are infected.

The launch of the campaign, dubbed “Know Your Status,” will be attended by the WHO’s Global Director for HIV/AIDS Jim Yong Kim as part of activities held to mark World AIDS Day in Africa, the continent worst hit by the epidemic.

Almost 26 million of the estimated 40 million people infected with HIV worldwide live in sub-Saharan Africa, and of almost 5 million new infections recorded in 2005 more than half occurred among Africans, the United Nations said this month.