Health authorities in Los Angeles County, California, have created an internet site where visitors can anonymously notify sexual partners that they may have been infected with a sexually transmitted disease (STD).
The site, www.InSPOTLA.org, went online on Wednesday. It offers various electronic postcards that can be emailed simultaneously to as many as six sexual partners who might be infected with an STD.
One card reads: "You're too hot to be out of action", and features the back of a man covering his behind with a towel. It goes on: "I got diagnosed with an STD since we played. You might want to get checked too."
The site provides information about how to avoid contracting several of the most common STDs.
Another card reads: "It's not what you brought to the party, it's what you left with. I left with an STD. You might have too. Get checked soon."
The service was developed by a non-profit group called the Internet Sexuality Information Services. It is co-sponsored by the AIDS Healthcare Foundation, with funding from the Los Angeles County.
Karen Mall, director of prevention and testing for the foundation, said: "Face-to-face communication is really the way to go, but some people can't do that."
Mall said that around 60,000 of the 10 million residents of Los Angeles County currently have HIV, the Aids virus, and a quarter of them do not know about it.
Jonathan Fielding, the county public health director, said: "This website will be a powerful tool in reducing the spread of STDs, including HIV, in LA County."
A similar site was launched in San Francisco in 2004, and 750 people visit it every day, officials say, with some 500 electronic post cards being sent out each month.