By Ania Lichtarowicz
BBC health reporter, Rio de Janeiro
Botswana has been praised by scientists at a conference in Brazil for its determination to tackle Aids/HIV.
President Mogae says his country is determined to beat HIV/Aids
Botswana is one of the countries worst affected by HIV infections. United Nations figures show that almost 40% of its population is HIV positive.
Life expectancy has fallen from 67 years in 1985, when the first case was identified, to 56 years today.
But fresh data shows Botswana is beginning to control the epidemic through its Aids programme.
Botswana's President Festus Mogae said that since the country started its Aids programme, the death rate has dropped dramatically.
Some scientists had predicted that if a major Aids programme was not implemented quickly, then life expectancy would drop by another 25 years in the next decade.
But Botswana is now not only running major prevention campaigns, it is rolling out treatment to almost 50,000 HIV-positive patients.
President Mogae said the country was determined to succeed.
"We didn't think we could possibly mount the anti-retroviral (ARV) therapy even if we could afford the ARVs," he said.
"But what is happening is that in spite of all the shortages of skilled human resources - that's nurses, doctors, laboratory and pharmacy technicians - we are doing not too badly."
Research presented at the conference in Rio de Janeiro shows that this approach is also working well in other African countries.
ARV treatment projects have been set up from scratch in Tanzania, Kenya, Mozambique, Rwanda and South Africa.
Despite obstacles like lack of experience, facilities and trained staff, these schemes are running well, showing that even in resource-poor settings, Aids treatment and prevention programmes can be successful.