A new campaign to warn gay and bisexual men about the risk of Shigella dysentery has been launched by Public Health England following a sharp rise in cases.

New figures show a surge in cases likely to have been sexually acquired over the past 12 months.

London is most affected.

In the UK, Shigella flexneri usually affects similar numbers of men and women and is linked with overseas travel, but 2013 data show an excess of more than 200 cases of the infection in men with no or unknown travel history, compared to women.

Shigella is a serious gut infection causing severe, prolonged diarrhoea and stomach cramps. Among gay and bisexual men, Shigella is usually passed on through the faecal-oral route during sex, either directly or via unwashed hands – only a tiny amount of bacteria can spread the infection. Symptoms often develop around 1-3 days after sex.

Men experiencing Shigella symptoms are advised to visit their GP or a clinic, specifically mentioning Shigella and requesting a stool sample test. The infection is treatable with antibiotics. Risk of infection can be reduced by avoiding oral contact with faeces during sex and washing hands thoroughly and showering after sex.

One of the men interviewed for Public Health England (PHE), who got Shigella through anal-oral sex (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.”

As part of the awareness campaign, posters and leaflets are being distributed in nightclubs, saunas and other gay venues, plus sexual health clinics, highlighting the symptoms of Shigella, how it is transmitted and how to avoid it.

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, said: “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 our free helpline THT Direct or visit the THT website.”