Research and analysis

HPR volume 20 issue 8: news (18 August 2026)

Updated 18 August 2026

National outbreak of Salmonella Enteritidis (t5.9411) in the UK

On 26 May 2026, the Gastrointestinal Infections, Food Safety and One Health (GIFSOH) division at the UK Health Security Agency (UKHSA) identified an increase in the number of cases of Salmonella Enteritidis caused by a single strain using whole genome sequencing (WGS) data. UKHSA has initiated an outbreak investigation, working with public health and food safety agencies in the UK and Devolved Administrations, and the Animal and Plant Health Agency (APHA) to identify additional cases, and consider potential sources of the outbreak to enable control measures to be implemented. Cases were interviewed with an outbreak questionnaire to gather information on severity of illness and risk factors for infection.

S. Enteritidis is the most common Salmonella serovar in England and the leading cause of salmonellosis in people (1). Like all non-typhoidal Salmonella, it is spread via consumption of contaminated food (including eggs, poultry, meat, unpasteurised dairy and fresh produce), contact with the environment, or person-to-person transmission. Symptoms of salmonella infection include diarrhoea, stomach cramps and sometimes vomiting and fever. Salmonella generally causes a self-limiting gastroenteritis, although immunocompromised individuals and those in vulnerable groups (young children and older adults) may experience more severe illness such as blood stream infections, infection of metastatic sites, sepsis and multiorgan failure.

As of 13 August 2026, 207 confirmed cases between 11 August 2025 and 1 August 2026 have been detected within this outbreak, all within the same 5-single nucleotide polymorphism (SNP) single linkage cluster based on WGS, indicating a common source of contamination. The majority of cases (206 out of 207) in this cluster were reported in 2026.

Cases were resident in England (n=199), Scotland (n=6), Wales (n=1) and Northern Ireland (n=1). For cases resident in England, the regions with the highest number of cases to date were London (n=47) and Yorkshire and Humber (n=38).

Figure 1. Number of Salmonella Enteritidis outbreak cases reported in 2026, over time, based on sample date (n=203 [note1])

Note 1: sample date not known for remaining 3 cases reported in 2026.

Cases range in age from 0 years to 90 years with a median age of 30. Across all age groups, 51% (n=105) were female.

Evidence gathered to date suggest that this outbreak is not associated with international travel, as only 6 out of 207 cases (3%) reported travel to countries outside of the UK.

Most people affected in this outbreak experienced self-limiting gastrointestinal illness; however, 38% of people with information available were admitted to hospital due to their salmonellosis symptoms and two people had a blood stream infection. There has been one death associated with this outbreak.

The Outbreak Control Team utilised the ECDC EpiPulse platform to notify member countries of the outbreak, and to understand whether other countries had identified genetically related Salmonella Enteritidis cases.

Extensive epidemiological and food chain investigations are ongoing to identify the source and origin of the contamination responsible for illness. To date, 114 cases have been interviewed and have a completed regional questionnaire or an outbreak questionnaire. Of those cases with a completed questionnaire, 95 (83%) report eating food prepared outside of the home in the week prior to symptom onset. Case interviews identified 5 food businesses where two or more independent cases reported attending in the week prior to symptom onset. These food businesses link 24 cases in total. Eleven of these cases report eating dishes made with eggs. The signal for egg consumption remains the strongest in this investigation to date. Food chain investigations to date have identified that these premises are supplied by eggs from multiple sources, including egg importers. Local investigations have also identified possible cross-contamination risk events within two of these settings. At this time there is no identified link to UK-produced eggs or poultry. The FSA is liaising with local authority environmental health teams who have provided advice on food safety management to food businesses where issues have been identified.

This outbreak of Salmonella Enteritidis is phylogenetically linked (within 25 SNPs) to a previous outbreak from 2025 which was also linked to imported eggs (2). UKHSA, alongside APHA, FSA and Devolved Administrations are working to collate the information gathered in these outbreaks to explore any potential risks posed from imported eggs and implement preventative measures if necessary.

References

1. UKHSA (2026). ‘Non-typhoidal Salmonella data 2015 to 2024’

2. UKHSA (2025). ‘Outbreak of Salmonella Enteritidis in the UK, November 2025’ Health Protection Report: volume 19, number 11