Warning to Britons as sexually transmitted gut infection now a 'distinct public health threat'

Cases of sexually transmitted shigella have risen steadily since 2023

A new study has identified sexually transmitted shigella as a "distinct public health threat" facing Britain, with researchers warning the bacterial infection is spreading at an alarming rate.

The research, conducted jointly by the University of Cambridge and the UK Health Security Agency, reveals that cases transmitted through sexual contact have risen significantly in recent years.

UKHSA data shows infections climbed from 2,052 in 2023 to 2,560 in 2025 across England. The findings, published in the Lancet Infectious Diseases journal, examined 3,514 Shigella samples collected from adults in the UK between 2004 and 2020.

Gay and bisexual men remain the group most affected by these particular strains.

The research uncovered striking differences in how sexually transmitted strains propagate compared with other forms of the infection.

Over a thirty-month period, strains passed through sexual contact travelled an average of 117 kilometres, while non-sexually transmitted variants spread just 46 kilometres.

Antibiotic resistance presents another growing concern for health authorities.

Some 70 per cent of sexually transmitted shigella strains demonstrated resistance to at least one clinically relevant antibiotic.

This compares unfavourably with 40 per cent resistance among non-sexually transmitted cases and 49 per cent among infections acquired during foreign travel.

The bacteria, which cause dysentery, typically produce symptoms including diarrhoea, stomach cramps and fever.

Professor Kate Baker, from the University of Cambridge's Department of Genetics, emphasised the lack of awareness surrounding this health risk.

"Many men who have sex with men are unaware of the serious and increasing risk posed by sexually transmitted shigella," she said.

"Sexual infection is now a sustained part of Shigella transmission in the UK. It is vital that this message reaches the communities most affected, so we can help to prevent the spread."

Prof Baker offered practical guidance for those concerned about infection.

"If you start to feel unwell, or are recently recovering from a scary bout of diarrhoea, do not engage in sexual activity until two weeks after you're fully recovered, mention your sexual history to your doctor if you seek medical care, and ask about having a full sexual health screen," he said.

The NHS lists several warning signs of shigella infection, including watery diarrhoea that may contain blood or mucus in severe cases, nausea, abdominal pain, and a temperature exceeding 38 degrees Celsius.

Marc Tweed, from the Terrence Higgins Trust, described the situation as "a real cause for concern".

He characterised Shigella's spread within certain sexual networks as a "growing problem" requiring urgent attention.

Mr Tweed encouraged anyone suspecting they may have contracted the infection to seek advice from their local sexual health clinic without delay.

The charity's intervention underscores the importance of community engagement in tackling this emerging public health challenge.