A Los Angeles porn star tested positive for HIV Tuesday and filming has been suspended at two of the US adult film industry's largest studios.

Wicked Pictures and Vivid Entertainment stopped production as a precaution when the positive test was revealed.

The actor, whose identity is withheld, was a patient of the Adult Industry Medical Healthcare Foundation, a San Fernando Valley clinic which primarily serves workers in the porn industry.

Jennifer Miller, clinic spokeswoman, said efforts are under way to notify persons who may have been sexually involved with the actor.

Adult film viewers regard condoms a turnoff, porn actors as a result don’t wear condoms and are exposed to the risk of contracting HIV and other sexually transmitted diseases at each filming.

The law requires porn actors to test negative for HIV and other sexually transmitted diseases within 30 days of going to work on a film.

Workers in the adult film industry are 10 times more likely to be infected with a sexually-transmitted infection than members of the general public, according to the Los Angeles County Department of Public Health.

Productions were briefly shut down in 2004 following the HIV positive result of a male actor which may have infected as many as 14 people who participated in the filming.