A new piece in the CDC’s Weekly Morbidity and Mortality Report (MMWR) has the results of a study on a norovirus outbreak that occurred in a Tennessee restaurant during Thanksgiving weekend in 2017.
On November 28, 2017, the manager of restaurant A reported receiving 18 complaints from patrons who had dined there on Thanksgiving Day four days before. All were suffering from gastrointestinal illnesses. The Tennessee Department of Health conducted an investigation and recommended measures to prevent further growth of the outbreak.
Investigators found that one person vomiting in a private dining room. An employee immediately used disinfectant spray that was labeled as effective against Norovirus to clean up. After washing his hands, the employee served family-style platters of food and cut pecan pie.
Restaurant A served 676 people a limited menu on Thanksgiving Day. The manager gave investigators contact information about who was at that meal. All patrons with contact information were called, and a questionnaire was sent out. One hundred thirty-seven people of the 676 were enrolled in a case study.
A probable case was defined as diarrhea or vomiting within 3 days of eating at the restaurant. Environmental swab were taken at the restaurant and tested for norovirus. Stool specimens identified Norovirus GII.P16-GII.4 Sydney, which was also found on a table leg next to the vomitus.
There were 36 case patients identified in this study. Most people got sick within 31 hours after eating at restaurant A. The mean illness duration was 3 days. Patients suffered from diarrhea, fatigue, nausea, vomiting, fever, and abdominal cramps.
The pecan pie was significantly associated with this norovirus outbreaks, but it was eaten by only 47% of the patients. People eating from 11:00 am to 1:00 pm were significantly more likely to get sick, since the patron vomited at noon.
Researchers think that transmission of the virus near the vomiting event occurred by aerosol or by touching contaminated surfaces. Norivirus spread through the restaurant occurred through the air, person-to-person contact, fomite (contaminated surfaces) and foodborne routes. Inadequate employee handwashing likely caused the pecan pie to become contaminated.
The moral of this study is that when anyone vomits, people who clean it up should wear gloves and gowns. Restaurants should have a written plan detailing how employees should deal with potential norovirus outbreaks; using protective gear is just one point. And the need for proper handwashing should be reinforced to prevent further norovirus outbreaks.
