Public health officials say there are a record number of syphilis cases in the Halifax area this year as the outbreak of the disease continues to grow.

Holly D'Angelo-Scott, a senior epidemiologist with public health in the Capital District Health Authority, said 47 men have tested positive for the sexually transmitted infection so far this year — up from 35 cases in all of 2011.

The affected men range in age from 18 to 66 years old. Many of them report having sex with multiple partners they met online.

"When we look to see the connections between cases, a lot of our cases are meeting their sexual partners through the internet," said D'Angelo-Scott.

"That's probably a common link between some of the cases."

D'Angelo-Scott said the syphilis outbreak in the Halifax area began in 2009. All the 115 cases confirmed syphilis cases since that time have been men — a similar pattern to outbreaks in other major Canadian cities.

But D'Angelo-Scott said infections may start to occur in local women too.

"It is possible that there will be a progression from this population of men who have sex with men to women," she told CBC News.

"We do have individual cases that report having sex with both men and women, or only women, and they do have infectious syphilis. So there's always the possibility of transmission."

D'Angelo-Scott said local men who report being infected by women may have acquired the disease outside of Nova Scotia, or even outside of Canada.

Syphilis can be transmitted by oral, anal and vaginal sex. Condoms provide protection, but D'Angelo-Scott said most infected men don't use them during oral sex. The earliest symptom appears about 21 days after transmission as a sore at the infection site.

The public health message message is clear.

"We're telling them that if they are engaging in unprotected sex, they need to get tested and tested on a regular basis," said D'Angelo-Scott.

Public health officials are working on an information campaign they hope to put on internet message boards where men go to seek sexual partners.

Syphilis tests are free and the disease is easily cured, normally with a single, free shot of antibiotics.