EDMONTON -- The Alberta government says anonymous hook-ups arranged on social media are the major reason for a dramatic spike in sexually transmitted infections in the province.

Cases of gonorrhea last year were up 80 per cent from 2014 and are the highest since the late 1980s.

The number of cases of infectious syphilis doubled in 2015 from 2014.

Dr. Karen Grimsrud, chief medical officer of health, says social media tools are helping people communicate quickly to arrange anonymous sexual encounters.

She says this makes it difficult to contact people for testing and treatment.

Health officials say the province will step up awareness campaigns that focus on the danger of anonymous hook-ups, encourage STI testing and for people to use condoms.