LOS ANGELES – A fourth adult film performer has tested positive for the virus that causes AIDS but the case is unrelated to an outbreak that virtually shut down pornography production last month, an industry health care official said on Tuesday.

A transsexual actress who goes by the stage name Jennifer tested positive for HIV on Tuesday and had last performed a sex scene on Feb. 27 with two male actors who have since tested negative, according to Sharon Mitchell of the Adult Industry Medical Healthcare Foundation.

The foundation runs an HIV screening program that tests porn actors every three weeks for sexually transmitted diseases and issues certificates that allow them to work.

The actors involved in the latest case will be tested again to rule out any possibility of further transmission of the deadly virus, Mitchell said.

“This is an open and shut case of genealogy,” she said. “We think it’s contained.”

Last month, HIV infections of three other porn stars prompted a 60-day shutdown of adult productions that employ 6,000 people, including about 1,200 performers. The suburban San Fernando Valley in Los Angeles is the hub of the U.S. porn industry.

Last month’s HIV outbreak prompted calls for unprecedented inspections of the multibillion-dollar industry and mandatory condom use — a proposition that critics said would drive the industry underground or out of the state.

California Assemblyman Tim Leslie, a Republican, has said the HIV outbreak showed that the industry’s self-regulation measures are failing.

Leslie is promoting a bill that would require testing of actors for sexually-transmitted diseases two weeks before every film shoot. The bill, which state lawmakers were expected to approve in a committee vote on Tuesday, also would bar infected actors from performing.