In August 2018 the Oregon Health Authority (OHA) and local health departments in Oregon investigated an outbreak of Shigella flexneri type 3a infections among people who attended a wedding and reception in Yamhill County on August 11. One hundred twelve cases were identified of which 23 (21%) were laboratory confirmed. Eighty-two (77%) of the cases were Oregon residents; the remainder were residents of 11 other states. Ten were hospitalized. All cases recovered.

Persons who attended the rehearsal dinner were no more likely to become ill than those who did not attend it (RR 1.1, p=0.54). Thus, the epidemiologic investigation focused on food exposure at the wedding reception. Food was catered by Pearl Catering, a company in located in Portland. Five food items were each associated with a significantly increased risk of illness: asparagus, butter, bread, au gratin potatoes, and the aioli that was served with the asparagus. Investigators concluded that the contaminated vehicle was asparagus attributing to poor food handler hygiene as the means of transmission.