Some of Alberta's sexually transmitted infection rates have spiked to levels not seen since the 1980s, and health officials blame social media.

Gonorrhea and syphilis have reached "outbreak levels," said Dr. Karen Grimsrud, the province's chief medical officer of health said at a news conference.

"We believe this is due to use of social media to set up sexual encounters."

Grimsrud said people often use anonymous online accounts to meet for sex.

"When people don't know their sexual partner's identity, that makes it difficult for public health to do the tracing for them and their contact, as far as setting up testing and treatment."

STI testing in Alberta is free and anonymous.

Sex, by the numbers

Overall, reported cases of gonorrhea in the province rose 80 per cent to more than 3,400 cases in 2015, from just under 2,000 cases in 2014. That's a rate of 82 cases/100,000 population, and the highest numbers reported in Alberta since the late 1980s.

Alberta Health Services has launched several public service campaigns to try to slow down the spike in STI rates. (iStock) The number of reported cases of syphilis more than doubled to 350 cases in 2015, from 150 cases in 2014. Officials say those numbers surpass a historic high last seen in 2009.

So far this year, numbers continue to climb. A total of 1,100 gonorrhea and 123 syphilis cases have been reported.

While all regions of the province saw an increase, Grimsrud said Edmonton had the most dramatic spike. Syphilis rates, for example, tripled in the city.

STI rates among women jump 93%

The overall rate of reported STI cases among women shot up 93 per cent in 2015, compared with the previous year.

Rates were highest among women aged 15 to 24.

' We believe this is due to use of social media to set up sexual encounters .' - Dr. Karen Grimsrud

The gonorrhea rate among men who have sex with men also "increased sharply," Grimsrud said. "It was 11 times higher than compared with men as a whole in the province."

Men were most at risk for syphilis with the number of cases doubling in 2015 compared to 2014.

Overall, most of the syphilis cases were in men who have sex with men — about 86 per cent.

Officials expect rates to increase in heterosexual men as well.

Rates up all around

B.C., Saskatchewan, Manitoba and Newfoundland have also seen increases in syphilis and gonorrhea rates recently, but officials said Alberta is often ahead of the pack on reporting.

"Alberta is typically one of the first provinces to report an increase in STIs, and that's because of our very good surveillance system," Grimsrud said.

Alberta Health hopes to reduce rates with PSA campaigns, a website called sexgerms.com, and targeted advertising.

Medical Officer of Health Gerry Predy said most STIs can be treated and cured.