Cases of sexually transmitted infections (STIs) increased in Scotland last year, with syphilis reaching a 15-year high.
There were 455 diagnoses of the condition – which can spread to the brain if left untreated – in 2018.
Health Protection Scotland (HPS) said that was the highest number recorded since its monitoring system was introduced in 2002-03, with the number of cases increasing by 14% on the previous year.
Almost all those diagnosed with the disease were male, with 96% of cases being in men – with 87% of these being found in men who have sex with men (MSM).
HPS said it “looks possible” that the increase could be linked to a decision to make the drug PrEP available on the NHS in Scotland to help prevent the spread of the HIV infection.
Its report said: “The impact of NHS-funded HIV pre-exposure prophylaxis (PrEP) is not yet fully understood, but it now looks possible that this intervention is associated with the observed increase in the incidence of STI diagnoses in MSM.”
Separate figures showed a 24% increase in gonorrhoea last year, as well as a small rise in genital chlamydia.
There were 3,233 cases of gonorrhoea reported in 2018, according to HPS – an increase of 103% from 2013.
Over the five years cases amongst men have increased by 121%, going from 1,056 to 2,339, with diagnoses in women going from 538 to 893 – a rise of 66%.
Meanwhile, there were 16,338 diagnoses of chlamydia in 2018, up from 15,685 the previous year.
HPS said that overall “young people, particularly women aged less than 25, are the group most at risk of being diagnosed with an STI”.