Syphilis rates in the Lower Mainland have spiked in the past year to the highest levels seen in decades.
The highly contagious sexually transmitted disease, once thought nearly wiped out in B.C., is mainly being seen in men who have sexual contact with other men.
Both the Vancouver Coastal and Fraser Health regions report their syphilis case numbers more than doubled from 2011 to 2012.
Vancouver Coastal saw nearly 300 cases last year or 80 per cent of the B.C. total.
Fraser reported 67 in 2012, up from 27 in both 2010 and 2011.
"We're concerned about the increasing numbers in Fraser even though it's not as bad as in Vancouver Coastal," said Dr. Paul Van Buynder, chief medical health officer for the Fraser Health Authority.
Some researchers have pointed to the advent of mobile phone apps for easily organizing anonymous gay sex hookups.
Van Buynder said he's not convinced that's the cause of the increase, noting gay or bisexual men seeking casual encounters have always been adept in finding each other.
He is concerned that some men involved shifted to oral rather than anal sex out of a belief it would reduce their risk of HIV infection.
"There was some reduction in the HIV transmission but it actually does nothing to decrease your syphilis risk," Van Buynder said.
He said the disease is one of the "great mimickers" because its symptoms can often be mistaken for bug bites or rashes, leading those infected to ignore it and spread the bacteria to others.
"I'm concerned that our physicians may not have seen this for a period of time," he said.
About 80 per cent of new cases are among men who have sex with men – a category that includes both gay and bisexual men as well as other men who don't identify themselves as such.
Public health officials are urging men in the LBGT community to get tested for syphilis every three to six months and to practice safer sex.
Other symptoms of syphilis include fever, swollen lymph glands and weight loss.
Catching the disease early and treating it with antibiotics is far easier than suffering the untreated consequences – permanent blindness, hearing loss, deep bone pain, neurological problems and even death.