A leading researcher has claimed that testing billions of people could eradicate HIV/AIDS within 40 years.

Dr Brian Williams of the South African Centre for Epidemiological Modelling and Analysis said that focus needed to shift to stopping transmission.

He told the annual meeting of the American Association for the Advancement of Science: “The problem is we’re now using HIV drugs to save people’s lives; we’re not using them to stop transmission.

“Can we use anti-retroviral drugs not only to keep people alive but also to stop transmission? I believe we can. I believe we can effectively stop transmission within five years.”

Dr Williams estimated that transmission of the disease could be halted by 2015 and that the epidemic could effectively be over by 2050 as most of those currently carrying the HIV virus will have died.

Anti-retroviral drugs work by lowering the viral load of the disease in a person’s blood, making them less infectious. Dr Williams said that usually, when people begin treatment, they have already infected everyone they would have infected during the window between transmission and accessing medical help.

Dr Williams told the meeting that people could be tested once a year and then treated if they are found to be carrying the virus. He said that other scientists supported the idea.

Globally, 33 million people are thought to carry HIV. Twenty-five million people are thought to have died in the epidemic.

Gay men and those from sub-Saharan Africa are typically most at risk, with one in ten gay men in London thought to be living with HIV.

However, the diagnoses rates in heterosexuals are rising.

Dr Williams said that HIV/AIDS was “one of the worst plagues in human history”.

He suggested that although mass screening programmes would be expensive, they would begin saving money “from day one” and he believed that people would be willing to take part.

He said: “The epidemic is killing half a million young adults every year at the prime of their life when they have started to contributed to society. The cost of that to society is enormous.”

Dr Williams is setting up a key trial in his home country at Hlabisa and similar studies are being carried out in US, Canada and sub-Saharan Africa to check feasibility.