A FOODBORNE OUTBREAK OF CAMPYLOBACTERIOSIS AT A WEDDING – MELBOURNE, AUSTRALIA, 2022

Campylobacter is the most common bacterial cause of foodborne gastroenteritis in Australia, however outbreaks caused by the pathogen are relatively uncommon. On 4 March 2022, the Victorian Department of Health was notified of a gastrointestinal illness in 20 guests following attendance at a wedding reception on 12 February 2022. Four individuals were notified with laboratory confirmed campylobacteriosis, and an investigation was undertaken to determine the full extent of the outbreak and prevent further illness. A nested case-control study was conducted to determine the likely source of infection. Cases were defined as attendees of the wedding reception, with onset of diarrhoea and/or abdominal pain 1-10 days after attending the function. Controls were randomly selected from the remaining non-ill guests. Cases and controls were interviewed using a standardised menu-based questionnaire, and odds ratios (ORs) calculated of consumed foods. Food preparation processes were documented, and food samples collected. A total of 29 wedding guests met the case definition, with onset of illness between 2-5 days and major symptoms including diarrhoea (90%), abdominal pain (100%), headache (79%), and fever (62%). Two cases were hospitalised, one with ongoing neurological sequelae. Illness was found to be significantly associated with consumption of a duck breast brioche canape containing duck liver parfait following univariate analysis and stratification by other implicated foods (OR=2.85, 95% CI [1.03-7.86]). Cases aged 10-29 years were 13.2 times more likely to have eaten duck than controls in that age group. The investigation found the duck canape was the likely vehicle of infection in this outbreak. Consistent with the literature on Campylobacter transmission, it is likely that inadequate cooking of the duck liver for the parfait was the contributing factor that led to illness. This outbreak investigation highlights the risks posed by poultry dishes if undercooked, and that education of food handlers remains a priority.