Gay men are being warned about a surge in cases of sexually acquired dysentery. The illness, which is caused by the Shigella flexneri bacteria, is a serious gut infection causing severe, prolonged diarrhoea and stomach cramps which is usually passed on through rimming or via unwashed hands.

Men experiencing Shigella symptoms – which include frequent and explosive diarrhoea lasting more than 48 hours, stomach cramps and fever – should visit their GP, who will prescribe antibiotics that quickly gets rids of the bacteria.

Shigella usually affects similar numbers of men and women and is linked with overseas travel, but 2013 data shows over 200 cases more than in 2012 in men with no travel history. London is most affected.

Interviews with gay and bisexual men who caught the infection through sex found links to high numbers of partners, often met anonymously online or at sex parties. Most of the men interviewed had not heard of Shigella before and thought they had food poisoning.

One of the men interviewed, who contracted Shigella via rimming, said: ‘Getting Shigella was the lowest point in my life. I suffered uncontrollable bloody diarrhoea with severe stomach cramps. The ferocity of symptoms and dehydration headaches made me think I was going to die. Initially I blamed it on a bad curry and held off visiting my GP for a week, but really wish I had gone straight away. Although it was treatable with antibiotics, the illness cost me a fortune as I had to take six weeks off work on statutory sick pay.’

Dr Gwenda Hughes, PHE head of STI surveillance, said: ‘Shigella is on the rise, so it is vital gay and bisexual men know about it and how to avoid getting it. We’re also seeing increasing HIV and gonorrhoea diagnoses among gay and bisexual men in the UK – indeed, most of the men with Shigella had been diagnosed with other STIs including HIV. This is a reminder how important it is to use a condom when having sex with casual and new partners.’

Cary James, Head of Health Improvement at Terrence Higgins Trust, added: ‘Although on paper the number of documented cases of Shigella are quite small, the concern is that not all cases are being reported. Men with symptoms who haven’t heard of Shigella before might assume it’s a particularly bad case of food poisoning. However, the infection can be dangerous, even more so if you’re already living with HIV or Hep C. We would urge anyone who is experiencing symptoms, or who’s concerned they may have been at risk, to call THT Direct on 0808 802 1221 or visit the Shigella pages on our website.’