In September 2023, the UK Health Security Agency identified cases of Salmonella Saintpaul distributed across England, Scotland, and Wales, all with very low genetic diversity. Additional cases were identified in Portugal following an alert raised by the United Kingdom. Ninety-eight cases with a similar genetic sequence were identified, 93 in the United Kingdom and 5 in Portugal, of which 46% were aged under 10 years. Cases formed a phylogenetic cluster with a maximum distance of six single nucleotide polymorphisms (SNPs) and average of less than one SNP between isolates. An outbreak investigation was undertaken, including a case–control study. Among the 25 UK cases included in this study, 13 reported blood in stool and 5 were hospitalized. One hundred controls were recruited via a market research panel using frequency matching for age. Multivariable logistic regression analysis of food exposures in cases and controls identified a strong association with cantaloupe consumption (adjusted odds ratio: 14.22; 95% confidence interval: 2.83–71.43; p-value: 0.001). This outbreak, together with other recent national and international incidents, points to an increase in identifications of large outbreaks of Salmonella linked to melon consumption. We recommend detailed questioning and triangulation of information sources to delineate consumption of specific fruit varieties during Salmonella outbreaks.

Following an outbreak of Salmonella Typhimurium in Wales in July 2021 associated with sheep meat and offal, further genetically related cases were detected across the UK. Cases were UK residents with laboratory-confirmed Salmonella Typhimurium in the same 5-single-nucleotide polymorphism (SNP) single-linkage cluster with specimen date between 01/08/2021–2031/12/2022. We described cases using routine (UK) and enhanced (Wales only) surveillance data. Exposures in cases in Wales were compared with non-Typhimurium Salmonella case–controls. Environmental Health Practitioners and the Food Standards Agency investigated supply chains of food premises reported by ≥2 cases. Animal, carcass, and environmental samples taken for diagnostic or monitoring purposes for gastrointestinal pathogens were included in microbiological investigations. We identified 142 cases: 75% in England, 23% in Wales and 3% in Scotland. Median age was 32 years, and 59% were male. Direct contact with sheep was associated with becoming a case (aOR: 14, 95%CI: 1.4–145) but reported by few (6/32 cases). No single food item, premises, or supplier linked all cases. Multi-agency collaboration enabled the identification of isolates in the same 5-SNP single-linkage cluster from a sheep carcass at an English abattoir and in ruminant, wildlife, poultry, and environmental samples, suggesting multiple vehicles and pathways of infection.

Excluding children with Shiga toxin-producing Escherichia coli (STEC) from childcare until microbiologically clear of the pathogen, disrupts families, education, and earnings. Since PCR introduction, non-O157 STEC serotype detections in England have increased. We examined shedding duration by serotype and transmission risk, to guide exclusion advice. We investigated STEC cases aged <6 years, residing in England and attending childcare, with diarrhoea onset or sample date from 31 March 2018 to 30 March 2022. Duration of shedding was the interval between date of onset or date first positive specimen and earliest available negative specimen date. Transmission risk was estimated from proportions with secondary cases in settings attended by infectious cases. There were 367 cases (STEC O157 n = 243, 66.2%; STEC non-O157 n = 124, 33.8%). Median shedding duration was 32 days (IQR 20–44) with no significant difference between O157 and non-O157; 2% (n = 6) of cases shed for ≥100 days. Duration of shedding was reduced by 17% (95% CI 4–29) among cases reporting bloody diarrhoea. Sixteen settings underwent screening; four had secondary cases (close contacts’ secondary transmission rate = 13%). Shedding duration estimates were consistent with previous studies (median 31 days, IQR 17–41). Findings do not warrant guidance changes regarding exclusion and supervised return of prolonged shedders, despite serotype changes.

A testing rate for measles above 80% is required by the WHO European Region Measles Elimination strategy to verify elimination. To comply with this rate, we explored factors associated with the return of oral fluid kits (OFK) by suspected measles cases. We described the cases and conducted a mixed-effects analysis to assess the relationship between socio-demographic and public health management characteristics and the likelihood of returning an OFK to the reference laboratory. Of 3,929 cases who were sent a postal OFK, 2,513 (67%) returned the kit. Adjusting for confounding, registration with a general practitioner (GP) (aOR:1.48, 95%CI:1.23–1.76) and living in a less deprived area (aOR:1.35, 95%CI:1.04–1.74) were associated with an increased likelihood of returning the OFK. The odds of returning the OFK also increased if the HPT contacted the parents/guardians of all cases prior to sending the kit and confirmed their address (aOR:2.01, 95%CI:1.17–3.42). Cases notified by a hospital (aOR:1.94, 95%CI:1.31–2.87) or GP (aOR:1.52; 95%CI:1.06–2.16) also had higher odds of returning the OFK. HPTs may want to consider these factors when managing suspected cases of measles since this may help in increasing the testing rates to the WHO-recommended level.

On 16–17 January 2020, four suspected mumps cases were reported to the local Public Health Authorities with an epidemiological link to a local school and football club. Of 18 suspected cases identified, 14 were included in this study. Laboratory results confirmed mumps virus as the cause and further sequencing identified genotype G. Our findings highlight that even with a high MMR vaccine coverage, mumps outbreaks in children and young adults can occur. Since most of the cases had documented immunity for mumps, we hypothesise that waning immunity or discordant mumps virus strains are likely explanations for this outbreak.