Investigation of a suspected Foodborne outbreak at a village in Leribe District, Lesotho, September 2021

Introduction: Foodborne diseases are estimated to cause 420,000 deaths annually. On 8 September 2021, the Leribe District Medical Officer was alerted of a foodborne outbreak rumour on a social media page. We conducted the investigation to confirm the outbreak and determine its cause. Methods: A case series was conducted at a Village in Lesotho in September 2021. A suspected case was defined as any person with acute diarrhoea with or without blood, seizures, nausea, vomiting, feeling feverish, dizziness, and/ or abdominal pain, burning sensation in the eyes, confusion with or without convulsions, frothing, decreased level of consciousness/ unconsciousness at a village in, Leribe district from 6-8 September 2021. We reviewed patient medical records and interviewed suspected cases. We investigated the exposure histories of case patients and inspected their homes for potential exposures. We exhumed the pig head and liver for toxin testing. Results: We identified six suspected cases aged 47 - 69 years. The cases presented with vomiting, dizziness, headache, fever, and confusion after consuming fried pork liver. The suspected liver was from a pig that escaped overnight and returned the following day displaying the behaviour of a wild animal. The owner slaughtered the pig, stored it in room temperature overnight and disembowelled the following day. All cases were hospitalised with one case dead. The suspected pork liver tested positive for arsenic. There was no evidence of recent agricultural chemical use in the gardens and the fields. Conclusion: This outbreak may have been caused by the consumption of pork liver positive for arsenic. Appropriate slaughtering practices should be observed and practised.