Cases of infectious syphilis are up 76 per cent over the past year, according to Ottawa Public Health, and the agency is asking those at risk to be screened.

All cases in the last year have been boys or men, more than 90-per-cent of whom report they are men who have sex with men, the agency said in a statement issued Thursday.

Syphilis is passed through oral, vaginal or anal sex and through skin-to-skin contact with a syphilis sore. Symptoms are usually mild and are often mistaken for something else.

Infected people sometimes don't know they have syphilis, so Ottawa Public Health is asking people at risk for the infection to be screened.

The screening is recommended for:

People who have a sexual partner diagnosed with syphilis.

People with multiple sexual partners, especially men who have sex with men.

Sexually-active people showing signs and symptoms consistent with syphilis.

Women who are pregnant or are considering pregnancy.

Condoms are only partially effective in preventing transmission.

Symptoms may include a painless sore and rashes which may include palms of the hands or soles of the feet. Untreated symptoms resolve in the short term but the infection is still there and needs to be treated with antibiotics.

Anyone who needs more information is asked to call the Ottawa Public Health Information Line at 613-580-6744 (TTY: 613-580-9656) or the AIDS and Sexual Health Information Line at 1-800-668-2437.