A sexually transmitted strain of the bacterial gut infection shigella is spreading more than twice as fast as other forms of the disease.
It is becoming increasingly resistant to antibiotics, researchers have warned, describing it as a distinct and intensifying public health threat.
The study, led by the University of Cambridge and the UK Health Security Agency (UKHSA) and published in the Lancet Infectious Diseases journal, analysed 3,514 shigella samples from people over 16 in the United Kingdom between 2004 and 2020.
Shigella is the bacteria behind dysentery, most commonly contracted through contaminated food and found in faeces.
It causes diarrhoea, stomach cramps, fever, and certain strains, specifically shigella sonnei and shigella flexneri, can also be spread through sexual contact, primarily among gay and bisexual men.
Over a two-and-a-half-year period, sexually transmitted shigella strains were found to spread an average distance of 117 kilometres, compared with 46 kilometres for non-sexually transmitted strains.
READ ALSO: How to Stay Safe When Heat Becomes Dangerous
The study also found that 70 per cent of sexually transmitted shigella strains were resistant to at least one clinically relevant antibiotic, against 40 per cent of non-sexually transmitted cases and 49 per cent of cases contracted while travelling.
UKHSA figures show sexually transmitted shigella cases in England rose from 2,052 in 2023 to 2,560 in 2025.
Prof Kate Baker of the University of Cambridge's Department of Genetics said many men who have sex with men remained unaware of the growing risk.
"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," she said.
She urged anyone who had been recently ill to exercise caution.
"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," she said.
Marc Tweed of the Terrence Higgins Trust described the growing problem as "a real cause for concern" and urged anyone who suspects they may have shigella to contact their local sexual health clinic without delay.
0 Comments