Xavier Robert Bissonnette, 56, is accused of sexually assaulting a 17-year-old girl. ((Calgary Police Service))

A 56-year-old Calgary man infected with HIV has been charged with sexually assaulting a teenage girl he picked up at a summer camp.

Calgary police said the man met the girl on an online dating site, communicating with her on several occasions.

It's alleged he drove to the camp last Friday where the central Alberta girl was enrolled and took her to a home in Calgary where the assault happened.

Calgary police were alerted after the RCMP relayed concerns that the girl had been taken out of the camp.

Police were able to track the suspect's vehicle to an address in southwest Calgary. When officers arrived they found the victim in distress and arrested the man, police said.

Xavier Robert Bissonnette is charged with aggravated sexual assault and is scheduled to make his first court appearance on Monday.

Bissonnette was diagnosed with HIV in 1998.The girl had been unaware of his HIV-positive condition, police said.

Investigators believe there might be others who have had unprotected sex with Bissonette, unaware that he is HIV-positive.