Facebook and other social network sites may soon have an app that can determine which one of its users has what sort of sexually transmitted disease, according to researchers.

Scientists are exploring whether websites like Facebook could be harnessed to filter through friend lists and flag up which of them may be carrying a sexually transmitted infection.

Researchers at the University of North Carolina’s Center for Infectious Diseases hope that social networks can be used to prevent the spread of diseases like HIV, gonorrhea and chlamydia.

Professor Peter Leone, leading the research, at an international health conference last month pointed out how a patient’s social networking circle can be a vital clue in detecting who could be at risk of infections.

Leone pointed out an example of how a syphilis outbreak in North Carolina showed how STDs can spread within a social circle.

“When we looked at the networks, we could connect many of the cases to sexual encounters, and when we asked who they hung out with, who they knew, we could connect 80 percent of the cases,” Leone said at the conference.

He explained that because social networks reflect our real-life friendship circles, services like Facebook could be used to contact an entire at-risk group to warn them that they may be in danger.

In a previous study Leone found that 20 percent of the sexual partners of newly diagnosed HIV patients were HIV-positive, suggesting that people in the same social circle often sleep with the same people as well as engage in similar risk-related behaviors.

Leon said that the STD-detecting app would be more precise approach to tracking the spread of STDs, rather than just focusing on at-risk demographics or limiting the search to those with whom the patient has had sex with.

Researchers said that one method for this approach would be ask newly diagnosed HIV patients to provide a list of past sexual partners and anyone else who could have been transmitted indirectly, and then the team would contact these people, sometimes through Facebook, to let them know that the patient is HIV-positive and that they should get themselves tested.

“People think that you have to be directly connected to someone, and I think of it as a population-level effect,” he told Salon. “It would be no different from someone who goes to a picnic and gets food poisoning. We’re concerned about everyone that was at that picnic.”

Another method considered by the team is based on an existing app, made by genetics professor James Fowler of the University of California in San Diego, for tracing the spread of flu. The app works by sifting through status updates for certain patterns and keywords and notifies users if the activity of their friends indicates that they may be at a higher risk of being infected.

Researchers noted that while a similar application for STI risk is imaginable, people are far less likely to broadcast news of their herpes flare-up than about their sore throat.

Fowler told Salon that changing behavior is hard, and he believes that a real, deep and social approach can slow the spread of STDs because when people see their friends talking openly about STDs online, spreading information about getting tested and using condoms may help normalize behavior and reduce social stigmas.

“There is good evidence that [in terms of sexual behavior] we’re influenced by seeing what our friends are doing,” Fowler said. “It takes real, deep, close social contact for people to change their behavior.”

“Social marketing is used to sell products, it certainly should be used to talk about health,” Leone concluded. “It takes the locus of control away from the public health system and really makes it about the relationships that exist already between friends.”