1 min

Ocular syphilis spreading among gay men on US Pacific coast

But no signs yet that is has reached Vancouver, BC

This image from the Review of Ophthalmology shows doctors how to recognize ocular syphilis with active deep stromal vessels (left) and inactive vessels (right). Credit:

A potentially blindness-causing strain of syphilis is spreading down the US Pacific coast, mostly affecting men who have sex with men, but there are no signs it has reached Vancouver yet.

According to the BC Centre for Disease Control, people at high risk of syphilis, such as gay men and people with HIV, should look out for inexplicable floating spots, a blue tinge, or flashing lights in their vision.

Normally, syphilis only rarely develops into ocular syphilis or causes blindness. In December, however, six men in Washington State were struck by ocular syphilis and two went permanently blind.

Four of the men are in King County, which includes Seattle. Three of them reportedly have sex with men, and three of them are HIV-positive, according to an advisory from King County health officials.

Dr Matthew Golden, director of the King County public health HIV/STD program, told The Stranger that some strains of syphilis are more likely to affect the brain, which could explain the unusual outbreak.

By March, cases of ocular syphilis had spread to San Francisco and then Los Angeles, prompting outbreak warnings from California health officials.

There are no signs yet, however, that the disease is spreading north.

Dr Troy Grennan, the head of the STI program at the BC Centre for Disease Control, says that while his team monitors all new cases of syphilis in the province, they haven’t seen any sign of the outbreak in Vancouver. Grennan says gay men and people with HIV should take the same precautions as usual: get regular STI testing, watch out for symptoms, and see a doctor for unexplained vision problems.

BC already has one of the highest rates of syphilis infection in Canada, and over three quarters of new cases are among men who have sex with men. 

In the past decade, syphilis rates among both heterosexuals and sex trade workers have declined, while rates among gay men have risen and then spiked dramatically in the past four years.