UPDATED: Illnesses are not limited to restaurant customers. People with whom the customers have had close contact have also reported illnesses.

Human transmission of norovirus is likely what made dozens, possibly hundreds, of people in Transylvania County, NC, sick in an outbreak among customers of a McDonald’s restaurant.

Samples collected from patients by their health care providers tested positive for norovirus. Those results were confirmed by the North Carolina State Laboratory of Public Health, according to the Transylvania County Public Health Department. Illnesses have been reported from customers of the restaurant and people with whom they have had close contact.

“Based on our current evidence, we believe it was due to human contamination rather than any one particular food or drink item,” Tara Rybka, public health educator with the county, told Food Safety News.

Rybka did not specifically say whether the person or people responsible for the contamination are employees at the restaurant. People can spread the virus to others and contaminate foods and other items before they begin to feel symptoms. 

The highly contagious norovirus is difficult to kill with sanitizers and can easily contaminate foods, beverages, surfaces such as counters, food containers and utensils. The virus can live on surfaces for long periods of time. 

Health care providers reported more than 70 cases of suspected foodborne illnesses to the county this past week. More than 200 other people called the health department themselves to report severe nausea, vomiting and diarrhea. Many of the sick people reported having consumed food and or beverages from a McDonald’s restaurant in Brevard, NC, on Asheville Highway.

Public health officials say there is no evidence that the outbreak in Transylvania County is related to the ongoing nationwide outbreak of cyclosporiasis related to McDonald’s salads containing salad mix from Fresh Express. Fresh Express, which is a subsidiary of the multi-national icon Chiquita Brands. That outbreak has sickened almost 400 people in 16 states with infections caused by the Cyclospora parasite. 

The operators of the McDonald’s in Brevard, NC, voluntarily closed the restaurant for a couple of days this past week to deep clean it. They reopened the location on Friday.

(To sign up for a free subscription to Food Safety News, click here.)