Study followed gay men from France and Canada over 18 months
Largest-ever study followed serodiscordant gay Aussie couples
PrEP, more frequent testing cited as factors
As HIV fears have faded, less condom use reported
Cost concerns voiced for public health care agency
Thousands participated in Australian study, researchers note
North Carolina, Mississippi, Louisiana have highest rates
Resource offers support on drugs, sex and alcohol abuse
Treatable disease cited in 24 cases since September 2015
City officials urge residents to get tested