Production of most adult films has stopped in Southern California while the performer is re-tested. The name and gender of the performer is not being released.
If the initial case is confirmed, the group will ask two generations of the person's sexual partners to get tested, meaning those who had sex with the performer and the sexual partners of those who had sex with the performer.
The voluntary industry shutdown affects porn producers in the San Fernando Valley, the heart of the multi-billion dollar American porn industry.
The porn industry was shut down similarly in late 2010, after a porn actor was diagnosed HIV positive.
A health advocacy group is hoping to place a measure on next year's Los Angeles city ballot requiring adult film performers to use condoms. Earlier this month they announced that it will gather 41,138 petition signatures to get the issue of condoms in porn on the June 2012 ballot.
The Associated Press contributed to this story.