The rate of new infections of HIV, the virus that causes Aids, among homosexual men has dropped for the first time since 2001, according to the Federal Health Office.
Figures released on Monday showed there were almost 100 fewer cases in 2009 than the previous year, a decline of 25 per cent.
The total number of new cases also fell – from 678 to 591 – for the first time since 2006. The highest level was in 2002, when 794 new cases were diagnosed.
The health office admitted there was “no conclusive explanation” for the “welcome decline”.
In November a United Nations report on Aids found that 50 people in Switzerland died of complications related to HIV infections in 2008. In 1995 the figure was 600. Antiviral drugs have helped people live longer with the disease, the report said.
Sub-Saharan Africa remains the most heavily affected area of the planet. About 22.4 million people, or two-thirds of all HIV-positive people, live with the disease there.
Since the beginning of the pandemic in the early 1980s almost 60 million people have been infected with HIV. About 25 million of them have died.
swissinfo.ch and agencies