Oregon Health Authority has released information about a Shigella outbreak that happened in August 2018 at a wedding in Yamhill County. One hundred seven people were allegedly sickened; 23 of those people had laboratory confirmed cases of shigellosis.
The wedding and reception took place on August 11, 2018. Over the next two days, wedding guests started reporting they were sick with vomiting and/or diarrhea fatigue, abdominal cramps, shaking chills, nausea, muscle aches, and bloody stools. Both Oregon Health Authority and Yamhill County Health and Human Services received reports of illness. The Multnomah County Health Department and the Oregon Department of Agriculture were informed about this outbreak.
Fecal samples from patients were cultured. On August 20, 2018, Shigella flexneri type 3a was identified in a specimen.
The caterer from the wedding and reception was contacted; they are based in Multnomah County. A menu was obtained, and wedding attendees were emailed a link to a survey asking them to identify foods they ate at the wedding and if they had been sick. Another survey was conducted when investigators discovered additional food exposures.
An official from Oregon Department of Agriculture inspected the venue, collected water samples and leftover strawberries and cucumbers, and looked at biosecurity at the event. Yamhill County specialists collected leftover potatoes. Food samples were tested for Shigella.
Among 263 wedding attendees and reception staff, 192 answered the first survey and 128 the second. In all, 107 Shigella cases were identified; 21% were confirmed. Most of the cases were Oregon residents. The median age of patients was 30 years. The average illness duration was 11 days, although it can take months before patients start feeling normal again.
Investigators focused on the wedding reception. Food was served buffet-style. Five items were identified that had a significantly increased risk of illness: asparagus, butter, bread, au gratin potatoes, and aioli served with the asparagus.
Of those who ate asparagus, 64% were sick, compared to 12.5% of those who said they did not eat asparagus. Asparagus consumption accounted for a higher percentage of cases, at 96%, than any other food. No asparagus was left over for testing.
There were no food handling violations at the caterer’s facility. Stool samples submitted by some of the staff were negative. The asparagus was sourced domestically. The venue’s water supply also tested negative.
Officials concluded that the outbreak of Shigella flexneri type 3a was most likely caused by contaminated asparagus. This outbreak was the second largest foodborne outbreak of Shigella flexneri infections in the U.S. since 1988. The source of the contamination was not definitely identified. The report concludes by stating that “poor food handlers hygiene is the most likely cause.”
