American Olympic eventer Darren Chiacchia has been charged with exposing his former boyfriend to the HIV virus.
Mr Chiacchia, of Ocala, Florida, has pleaded not guilty to the charge and faces up to 30 years in jail if found guilty, according to American media.
The 45-year-old rider helped the US eventing team to win bronze at the Athens Olympics in 2004.
He had been aiming for the 2008 Beijing Games when he suffered a in a severe head injury, multiple rib fractures and a partially collapsed lung rotational fall at Red Hill Horse Trials.
It is reported that he learned he was HIV positive while in hospital recovering from the accident.
Mr Chiacchia was arrested in January after a former partner pressed charges against him and is due to be tried in June.
Floridian law states that people with HIV must inform their sexual partners that they have the condition.
Updated: 22 February 2017
An online docket for Marion County, Florida dated 15 February 2017 confirms that 2010 felony charges alleging that Darren did not inform a former sexual partner that he was HIV positive have been dropped.