# P-578. Foodborne outbreak at a public school in Mangystau region, Kazakhstan, 2024

## TL;DR

A foodborne illness outbreak affected 141 people at a school in Kazakhstan, with contaminated chicken and mashed potatoes identified as likely sources.

## Contribution

The study identifies specific food items and pathogens linked to a large school outbreak and led to nationwide food safety improvements.

## Key findings

- Contaminated chicken and mashed potatoes were strongly associated with illness (aRR=1.2 for both).
- S. sonnei was the most frequently isolated pathogen (56% of participants).
- Environmental assessments revealed significant food safety violations in the school canteen.

## Abstract

On 7 September 2024, 141 students and staff members at a public school in Kazakhstan reported gastrointestinal illness. All had eaten daily at the school canteen. We investigated the outbreak and suggested measures to prevent similar future outbreaks.Table 1.Factors associated with food poisoning in a public secondary school in Beshoky, Munaili district, Kazakhstan in September 2024: bivariate and multivariate analysis.RR: Relative risk95% CI - LL: Confidence interval low limit95% CI - UL: Confidence interval upper limitaRR: Adjusted relative riskP-value of Z test; all variables in the table are included in the Poisson regression model.

Factors associated with food poisoning in a public secondary school in Beshoky, Munaili district, Kazakhstan in September 2024: bivariate and multivariate analysis.

RR: Relative risk

95% CI - LL: Confidence interval low limit

95% CI - UL: Confidence interval upper limit

aRR: Adjusted relative risk

P-value of Z test; all variables in the table are included in the Poisson regression model.

We conducted a retrospective cohort study of students and staff who ate in the canteen during September 4-6, 2024. Cases were anyone experiencing diarrhea, vomiting, or abdominal pain from September 4–13. We interviewed consenting staff, canteen food handlers, and students, and reviewed medical records for those hospitalized. We collected participant and food handler samples [stool, rectal swab, or vomitus], food products, and surface samples. We used multivariable Poisson regression to estimate adjusted risk ratios (aRR) for exposures associated with illness.

Among 1,299 cohort members, 621 (48%) cases were identified; 93% were aged 5–12 years. Symptoms peaked on September 6–7 and included bloody diarrhea (74%), abdominal pain (70%), fever ≥38°C (68%), and vomiting (58%). Illness was associated with ages 5–11 vs ≥12 years (aRR=1.2, 95%CI=1.1–1.3), first-shift school attendance vs second-shift (aRR=1.1, 95%CI=1.02–1.08), consumption of mashed potatoes containing eggs (aRR=1.2, 95%CI=1.1–1.3), compote (aRR=1.1, 95%CI=1.05–1.14), and chicken served on September 5-6 (aRR=1.2, 95%CI=1.13–1.27) (Table 1). We isolated S.sonnei, S.aureus, K.pneumoniae, and P.vulgaris in 56%, 17%, 7%, and 2% of participants, respectively. Among food handler, S.aureus was found in 17% and P.vulgaris in 100%. P.vulgaris and S.aureus were detected in four chicken and mashed potato food samples from September 6. In total, 528 (85%) cases had eaten chicken, and 512 (82%) mashed potatoes. Environmental assessment revealed numerous food safety violations (cross-contamination, food storage temperatures, hygiene practices).

The investigation highlighted critical gaps in food safety and a lack of monitoring in Kazakhstan’s schools. This led to a country-wide school canteen inspection program and food safety training for 7,471 schools.

All Authors: No reported disclosures