David Magnum, 37, of Dexter, Missouri, is shown in this undated police booking photo provided by the Stoddard County Prosecutor's Office in Bloomfield, Missouri on September 5, 2013. REUTERS/Stoddard County Prosecutor's Office/Handout via Reuters

By Carey Gillam

(Reuters) - A Missouri man was arraigned Thursday on charges that he recklessly infected a sexual partner with the virus that causes AIDS, and a prosecutor said he potentially could have infected 300 more people in two states.

David Mangum, 37, faces a felony charge in Stoddard County Circuit Court in southeastern Missouri accusing him of exposing a 29-year-old man to human immunodeficiency virus (HIV), which causes a life-threatening failure of the immune system commonly known as AIDS, according to court documents.

As well, Mangum admitted to having unprotected sex with more than 300 partners in Missouri and Texas since learning he was HIV positive in 2003, some of whom he had met through ads on the Craigslist Internet site, the court documents said.

"This situation is a serious public health concern, Russell Oliver, Stoddard County Prosecuting Attorney, said in a statement. "There are potentially 300 or more unknown victims that have been unknowingly exposed to HIV in this region. If any of those 300 individuals contracted the virus, all sexual partners of those victims have potentially been exposed."

Mangum, who worked in a grocery store in Dexter, Missouri, was arrested after his former partner learned in July that he was HIV positive. The man told police that Mangum had lied about having the virus.

Dexter Police Detective Cory Mills said Mangum told him he hid his HIV status from sexual partners because he feared they would reject him.

Mangum was assigned a public defender and his bail was set $250,000.

(Reporting By Carey Gillam in Kansas City; Editing by Tim Dobbyn)