SAN DIEGO (CNS) - A 30-year-old San Diego man who knowingly exposed his partner to the HIV virus pleaded no contest Monday to a violation of the state health code.

Thomas Miguel Guerra, who entered the plea on the day his trial was to go forward, faces up to six months in custody and a $1,000 fine when he is sentenced April 13.

According to the City Attorney's Office, Guerra's case is the first prosecution of willful HIV transmission in San Diego. The office found no previous successful prosecution of its kind in the 20 years since the

California Legislature adopted the statute.

The City Attorney's Office said it was prepared to prove that Guerra knew he was HIV-positive and that he unlawfully had unprotected sex with the victim without disclosing his HIV status.

"I hope this case helps to educate people that it is a crime to willfully expose someone to an infectious disease," said City Attorney Jan Goldsmith. "The law is designed to protect the public and, in this case, the right of one's partner to know the truth."

The case began in August 2013 when Guerra's partner filed a complaint with the San Diego Police Department.

According to the City Attorney's Office, the victim told police that:

-- he and Guerra were in a romantic relationship for several months in 2013;

-- that Guerra claimed to be HIV-negative and the two had unprotected sex at Guerra's urging;

-- the victim learned he was HIV-positive in May 2013 after previously testing negative, and;

-- after the relationship ended, the victim learned that Guerra knew he was HIV-positive before the relationship began.