LOS ANGELES (AP) - A pornography trade group is calling for a nationwide filming moratorium while performers are tested for syphilis and Los Angeles public health officials investigate an outbreak.

Free Speech Coalition spokeswoman Joanne Cachapero says Monday that one performer has tested positive for the sexually-transmitted disease and the performer's sexual partners are being notified.

The self-imposed moratorium shutters a multi-billion adult film industry, with many major producers based in Los Angeles county's San Fernando Valley.

The call for a moratorium came Saturday, one day after the Los Angeles County Public Health Department announced an investigation into at least five possible cases last week.

County health officials Monday acknowledged the investigation, but declined an interview seeking details of its scope or an update of the investigation's findings.

Copyright 2013 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.