A highly drug-resistant gonorrhoea outbreak has been detected in the north of England, prompting a nationwide alert.
The outbreak, first detected in Leeds in March, has now spread - with cases now reported in patients in Macclesfield, Oldham and Scunthorpe.
Fifteen cases have been detected by Public Health England so far, the British Association for Sexual Health and HIV said.
Reports to PHE's sexually transmitted bacteria reference unit of cases of the infection being highly resistant to the azithromycin drug have previously been rare, it added.
All of the cases involve heterosexual patients, and some people have reported partners from other parts of England.
The association said:
There were almost 35,000 cases of gonorrhoea reported in England last year - it is the second most common bacterial sexually transmitted infection in the UK after chlamydia.
The majority of cases affect people under the age of 25. Around 10% of men and almost half of women with the infection do not experience symptoms
Whilst the number of infections may seem small, a sexual health expert told the BBC that there could be more undetected cases.
This latest outbreak adds to growing concern that gonorrhoea and several other illnesses are becoming untreatable.