LOS ANGELES – A third adult movie performer tested positive Thursday for the virus that causes AIDS in the midst of an HIV outbreak that has halted most production, according to the director of an AIDS testing service.

“This is not over,” said Sharon Mitchell, executive director of the nonprofit Adult Industry Medical Healthcare Foundation, which screens performers for sexually transmitted diseases.

Mitchell declined to identify the woman diagnosed Thursday but said the performer had sex with five men before all were barred from adult movie sets under a voluntary quarantine in place since the first HIV case was announced on April 12.

A total of 53 people are on the quarantine list and dozens of producers have shut down production until further HIV testing gives the all-clear.

The last HIV scare in the nation’s multibillion dollar porn industry was in 1999 and involved only a single case.

In the latest outbreak, an actor with the stage name Darren James apparently contracted HIV while filming unprotected sex scenes in Brazil. He returned to the United States and apparently infected performer Lara Roxx during film shoots, Mitchell said.

Los Angeles County health officials and the state’s Division of Occupational Health and Safety are investigating.

Meanwhile, the American Civil Liberties Union of Southern California claimed Thursday the county Department of Health Services violated the law by obtaining private medical information on potentially HIV-infected performers without a subpoena.

The ACLU and Being Alive Los Angeles, a group of 800 people with HIV or AIDS, sent a letter to the director of the health department’s sexually transmitted disease program.

“The government needs to make a showing that the breach of the confidentiality is warranted and the way to do that is by going through the court,” said Peter Eliasberg, the chapter’s managing attorney.

If people think the government can obtain their private records, it may deter them from getting HIV tests, he said.

County Health Officer Jonathan Fielding said he had not seen the letter and could not comment on the allegations.

Mitchell said her attorney indicated she had no choice last week when she turned over the records. The documents included three months of negative HIV tests for 51 potentially HIV-exposed actors on the quarantine list along with their names and contact information, she said.

No records on the two actors who had tested HIV-positive at the time were handed over because of state privacy requirements, she added. Mitchell said she was advised that she must cooperate because the county had declared an HIV outbreak, and that it could obtain a subpoena for all of her organization’s medical records if she refused.

Mitchell said the information was to be used only by the health department to interview the performers and determine whether they may have passed on HIV to people outside the porn business.

“I wasn’t happy” about turning over the records, she said. “It has provided a lot of difficulty for us and raised trust issues among the community I serve.”