Porn star 'Mr Marcus' jailed for knowingly exposing co-stars to syphilis and causing outbreak that closed the industry Porn star Mr Marcus admitted altering his syphilis-positive test results to continue performing in adult films He hid the details of the bacterial infection when showing producers his blood test results The adult film industry shut down after at least nine porn stars contracted the infection A male porn star has been sentenced to 30 days in jail after admitting responsibility for the syphilis outbreak that closed down the adult film industry in Los Angeles last August. 'Mr Marcus', 42, whose real name is Jesse Spencer, contracted the bacterial infection on set before altering his syphilis-positive test so he could continue performing. The 19-year veteran pleaded no contest in Los Angeles Superior Court where he was also sentenced on Tuesday to 36 months' probation and 15 days of community labor. In August his admission came after the industry's self-imposed 10 day moratorium which saw more than 1,000 performers in the LA area get tested and administered preventative antibiotics. Jailed: Porn star Mr Marcus has been sentenced to 30 days in jail after continuing to work after contracting the bacterial infection At least nine porn stars were revealed to have contracted syphilis. Mr Marcus said: "I tried to cover it up...because I said it was like the scarlet letter. It's the word. Syphilis, whoa. Mr Marcus, syphilis? Mr Marcus, the one I worked with? The one that everybody works with? The one that's been in this industry forever? Returned to work: His doctor said Mr Marcus would not be contagious 10 days after a pencillin shot so he returned to work at porn shoots after 11 days A doctor told Mr Marcus that he would not be contagious 10 days after taking a shot of penicillin on July 13. With that diagnosis he returned to work 11 days later, on July 24, still with syphilis. Instead of presenting a paper or digital copy of the test results he showed the producer a copy on his phone so the details about the infection were not visible. While filming another porn film, Mr Marcus said he folded the test to hide the syphilis diagnosis and photocopied it but a producer noticed the results were missing and questioned him about it. He said: "I have to live with this, no one else does. I'm very sorry. I did not think that this would come out like this. The porn star posted on Twitter yesterday: "You can be disappointed, but don't throw stones. Some of you are living in glass houses. The bacterial infection has a 90-day incubation period meaning a porn actor could potentially be carrying the disease without it showing up on tests. Porn star Aletta Ocean, 24, said she contracted syphilis while shooting movies in Budapest, Hungary. Her revelation led to speculation that the outbreak of the disease came from Hungary. On hold: Pornographic films are being set outside of Los Angeles because of the city's law that now requires performers to wear condoms, leading to increased permit requests in neighboring towns According to porn industry blog LukeIsBack.com she tweeted: 'F****** siphilis problem... In Budapest many people got it..Me too... Sex workers are supposed to undergo regular blood tests to ensure they are free of sexually transmitted disease. It was reported that one of the labs frequented by porn stars does not test for syphilis. Speculation it came from Hungary: Porn star Aletta Ocean said on Tuesday that she contracted syphilis in Hungary leading to speculation that the outbreak came from there Syphilis is a treatable bacterial infection that can be spread by both bodily fluids and contact with infected skin. Its causes skin lesions and rashes. If left untreated, it can permanently alter and damage internal organs and brain function. The number of syphilis cases in California has jumped 18 per cent according to a report from the California Department of Public Health. The results showed a much higher rate of men had contracted the infection and that African Americans were affected more than any other racial demographic. Requests for filming permits for porn shoots have dropped dramatically since LA imposed a law forcing performers to wear condoms during sex scenes. Neighboring towns are now putting a moratorium on permit approvals as they deal with an influx from production companies who are looking for places to film without condoms. LA residents voted in November to force actors in pornographic films to wear condoms during shoots, and now the industry is feeling the results as many producers have opted for different shoot locations.