Anti-retroviral treatments (ARVs) could stop the spread of Aids in South Africa within five years, say scientists.

科学家称，抗逆转录病毒疗法可以在五年之内阻止艾滋病在南非的传播。

South Africa has the world's highest incidence of HIV/Aids

Dr Brian Williams said that by providing HIV positive patients with these drugs could stop the spread at a cost of around $2-3 billion per year.

The drugs reduce the amount of virus patients have in their body fluids（体液） .

Dr Williams called for this approach at the annual meeting of the American Association for the Advancement¹ of Science (AAAS美国科学发展协会) in San Diego.

Dr Williams, a leading figure in the field of HIV research, is based at the South African Centre for Epidemiological（流行病学的） Modelling and Analysis (Sacema) in Stellenbosch.

He said the scale of the problem in South Africa was "enormous".

Success story

He added: "We have 30 million people infected with HIV and two million people dying each year."

"The tragedy is that the disease continues unabated（不减弱的，不衰退的） . The only real success story is the development of these extremely effective drugs that keep people alive and reduce their viral（滤过性毒菌的） load by up to 2000 times. They become close to non-infectious.

"We should be looking at using the drugs to reduce transmission."

He said that if clinical trials started now, all of the HIV positive people in South Africa could be on ARV treatment within five years.

This approach, he stressed, should be complementary（补充的） to the search for an Aids vaccine². An effective vaccine, he said, was still a long way away.

Dr Williams commented: "Even with a vaccine, in South Africa we would still have all of these people who are already infected - so what do we do for them?"

Kenneth Mayer, professor of medicine at Brown University in the US state of Rhone Island, agreed that treating patients early with ARVs was a matter of "public health".

Dr Williams said a few clinical trials were already beginning in North America and in Africa.

The US National Institute of Allergy³ and Infectious Diseases is planning a trial in New York and Washington - in districts that have an HIV positive population at a similar level to African epidemics⁵.

"We need to get answers [from these trials] quickly. That will help us move forward," he stressed.

"We could break the back of the epidemic⁴. If we can do it, I'm confident it will work."