According to a report from the Kansas Department of Health and Environment:

On Sunday, June 2, 2013 at 6:36 p.m., the Salina‐Saline County Health Department (SSCHD) received a call from Salina Regional Health Center (SRHC). SRHC reported that a patient in the emergency department was ill with gastrointestinal symptoms, and the patient knew of several others ill with similar symptoms who presented to Abilene Memorial Hospital. All the ill individuals attended a rehearsal dinner at Martinelli’s Little Italy Restaurant (158 S Santa Fe, Salina, KS, 67401) on May 31, 2013, and a wedding reception held at a different Salina location on June 1, 2013. SSCHD contacted the Kansas Department of Health and Environment’s Infectious Disease Epidemiology and Response section (KDHE) at 7:29 p.m. to report the
possible outbreak.

The following morning, SSCHD, KDHE, and the Kansas Department of Agriculture (KDA) began an investigation to determine the cause and scope of illness, and to implement prevention and control measures.

CONCLUSION 
Twenty‐eight cases and five secondary cases of gastroenteritis were associated with consuming food at a wedding rehearsal dinner at Martinelli’s Little Italy on May 31. Additionally, five others reported gastroenteritis after consuming food from the restaurant on that evening. Norovirus was confirmed as the causative agent among three individuals who attended the wedding rehearsal dinner and one individual who was not related to the wedding group. The symptoms, incubation time, and duration of illness reported are consistent with norovirus infection.
Although the restaurant was associated with illness, the vehicle of transmission could not be confirmed. The salad served at the wedding rehearsal dinner was statistically linked with illness; however, of the two other groups who ate food from the restaurant that evening, one consumed salad and one did not. Multiple menu items may have been contaminated with norovirus.

Norovirus is a highly contagious pathogen with a very low infectious dose, estimated to be between 10‐100 viral particles1. Transmitted primarily through the fecal‐oral route, norovirus particles may be spread through direct contact or through consuming fecally‐contaminated
food or water. Spread via aerosolized vomitus is also possible. The incubation period is normally 24 to 48 hours, and can range from 10 to 50 hours.2 Once infected, norovirus shedding can begin prior to the onset of symptoms and can persist for weeks after clinical symptoms
have ceased.

Norovirus has been detected in fecal specimens 3 to 14 hours before the onset of clinical symptoms and could be detected for 13 to 56 days after exposure to the virus3. Approximately 20% of norovirus infected individuals do not have clinical symptoms4. However, these individuals can still shed norovirus and can be potential sources of contamination. Investigations of foodborne norovirus outbreaks have implicated multiple food items, including oysters, salads, sandwiches, cakes, frosting, raspberries, drinking water, ice, and other food
items that were contaminated after cooking or that were ready to eat.

The epidemiological investigation was limited by several factors. First, the scope of illness was not fully determined. More extensive case finding, such as the use of credit card receipts to identify additional individuals who dined at the restaurant, could have been useful in
determining the full extent of the outbreak. Inaccuracies may be present in interviewees’ food and symptom histories due to recall bias.

This investigation was aided by SSCHD’s communications to area physicians, which allowed for the identification of an affected individual outside of the wedding group, as well as the collection of additional stool specimens for norovirus testing. The use of an online questionnaire, in combination with a mailed questionnaire, allowed for a good response rate while minimizing the staff time required for the investigation.

Because of initial uncertainty as to which wedding event was the source of illness, two inspections had to be conducted. KDA
conducted both inspections within 48 hours of notification.