Category Archives: Norovirus

USA – Foodborne Illness Outbreaks at Retail Food Establishments — National Environmental Assessment Reporting System, 25 State and Local Health Departments, 2017–2019



Problem/Condition: Each year, state and local public health departments report hundreds of foodborne illness outbreaks associated with retail food establishments (e.g., restaurants or caterers) to CDC. Typically, investigations involve epidemiology, laboratory, and environmental health components. Health departments voluntarily report epidemiologic and laboratory data from their foodborne illness outbreak investigations to CDC through the National Outbreak Reporting System (NORS); however, minimal environmental health data from outbreak investigations are reported to NORS. This report summarizes environmental health data collected during outbreak investigations and reported to the National Environmental Assessment Reporting System (NEARS).

Period Covered: 2017–2019.

Description of System: In 2014, CDC launched NEARS to complement NORS surveillance and to use these data to enhance prevention efforts. State and local health departments voluntarily enter data from their foodborne illness outbreak investigations of retail food establishments into NEARS. These data include characteristics of foodborne illness outbreaks (e.g., etiologic agent and factors contributing to the outbreak), characteristics of establishments with outbreaks (e.g., number of meals served daily), and food safety policies in these establishments (e.g., ill worker policy requirements). NEARS is the only available data source that collects environmental characteristics of retail establishments with foodborne illness outbreaks.

Results: During 2017–2019, a total of 800 foodborne illness outbreaks associated with 875 retail food establishments were reported to NEARS by 25 state and local health departments. Among outbreaks with a confirmed or suspected agent (555 of 800 [69.4%]), the most common pathogens were norovirus and Salmonella, accounting for 47.0% and 18.6% of outbreaks, respectively. Contributing factors were identified in 62.5% of outbreaks. Approximately 40% of outbreaks with identified contributing factors had at least one reported factor associated with food contamination by an ill or infectious food worker. Investigators conducted an interview with an establishment manager in 679 (84.9%) outbreaks. Of the 725 managers interviewed, most (91.7%) said their establishment had a policy requiring food workers to notify their manager when they were ill, and 66.0% also said these policies were written. Only 23.0% said their policy listed all five illness symptoms workers needed to notify managers about (i.e., vomiting, diarrhea, jaundice, sore throat with fever, and lesion with pus). Most (85.5%) said that their establishment had a policy restricting or excluding ill workers from working, and 62.4% said these policies were written. Only 17.8% said their policy listed all five illness symptoms that would require restriction or exclusion from work. Only 16.1% of establishments with outbreaks had policies addressing all four components relating to ill or infectious workers (i.e., policy requires workers to notify a manager when they are ill, policy specifies all five illness symptoms workers need to notify managers about, policy restricts or excludes ill workers from working, and policy specifies all five illness symptoms requiring restriction or exclusion from work).

Interpretation: Norovirus was the most commonly identified cause of outbreaks reported to NEARS, and contamination of food by ill or infectious food workers contributed to approximately 40% of outbreaks with identified contributing factors. These findings are consistent with findings from other national outbreak data sets and highlight the role of ill workers in foodborne illness outbreaks. Although a majority of managers reported their establishment had an ill worker policy, often these policies were missing components intended to reduce foodborne illness risk. Contamination of food by ill or infectious food workers is an important cause of outbreaks; therefore, the content and enforcement of existing policies might need to be re-examined and refined.

Public Health Action: Retail food establishments can reduce viral foodborne illness outbreaks by protecting food from contamination through proper hand hygiene and excluding ill or infectious workers from working. Development and implementation of policies that prevent contamination of food by workers are important to foodborne outbreak reduction. NEARS data can help identify gaps in food safety policies and practices, particularly those concerning ill workers. Future analyses of stratified data linking specific outbreak agents and foods with outbreak contributing factors can help guide the development of effective prevention approaches by describing how establishments’ characteristics and food safety policies and practices relate to foodborne illness outbreaks.

Research – Cruise Ship Illness Cases Surpass 2019 Levels – What It Means

Cruise Hive

Recorded outbreaks of gastrointestinal illnesses have been reported aboard 12 cruises so far in 2023, already surpassing the total number of outbreaks in 2019, the last year of full data available. Does this mean that cruises have become unhealthier or at higher risk for such outbreaks?

12 Outbreaks in Less Than 5 Months

Only five months into 2023, a dozen outbreaks of gastrointestinal illnesses aboard cruise ships have been reported to the Vessel Sanitation Program (VSP) of the US Centers for Disease Control and Prevention (CDC).

USA – Norovirus outbreak linked to California restaurant sickens nearly 100

Food Safety News


A norovirus outbreak originating from a California restaurant has sickened about 100 people, according to the San Luis Obispo County Public Health Department.

Jessie Burmester, an epidemiologist from the health department, told KSBY news that 97 cases have been confirmed in connection with the outbreak earlier this month. While Burmester did not disclose the name of the restaurant involved, she revealed that the investigations consistently pointed to the same establishment.

“Our primary objective during investigations is to identify a common source or exposure point,” Burmester said. “Thus far, all individuals reporting illness have consistently provided the name of the restaurant.”

RASFF Alerts – Norovirus – Clams


Norovirus genogroup I and II in live clams (Chamelea gallina) from Italy in Spain


Norovirus genogroup I and II in clams from Italy in Spain


Norovirus genogroup I and II in japanese clam from Portugal in Spain

RASFF Alerts – Norovirus – Clams – Japanese Clams


Norovirus genogroup I and II in clams from Italy in Spain


Norovirus genogroup i and ii in japanese clam from Portugal in Spain

RASFF Alerts – Norovirus – French Oysters


Presence of norovirus genogroup I in oyster from France in Spain


Presence of Norovirus type I in oysters (Crassostrea gigas) from France in Spain

Research – Norway records rise in outbreaks in 2022

Food Safety News

The number of outbreaks and people sick in them in 2022 went up from the year before, based on new data from Norway.

A total of 34 foodborne outbreaks were reported in 2022, which is up from 23 and 25 outbreaks in 2020 and 2021 but lower than the 46 outbreaks in 2019.

Overall, 628 people were sick this past year with the largest incident affecting 100 people, according to a report published by the Norwegian Institute of Public Health (FHI). In the 25 outbreaks in 2021, 327 patients were recorded.

Eight norovirus outbreaks sickened 135 people in 2022. Five outbreaks with 148 cases were caused by Salmonella. Cryptosporidium and Yersinia were behind three each with 14 and 51 patients, respectively.

Ten people were sick in two Listeria outbreaks. One Campylobacter outbreak had six patients and one E. coli event affected seven people. The agent was unknown for 11 outbreaks with 257 cases.

Most foodborne outbreaks were reported in connection with restaurants, cafes and other catering establishments.

RASFF Alert- Norovirus – French Oysters


Norovirus in oysters from France in Belgium

Research – Getting Creative To Combat Foodborne Norovirus

Technology Networks

Every year, norovirus causes hundreds of millions of cases of food poisoning — and the deaths of at least 50,000 children — yet there exists no real way to control it. The virus has proven exceptionally difficult to study in the lab, and scientists have struggled to develop effective vaccines and drugs.

A new study at Washington University School of Medicine in St. Louis describes a creative way to make a vaccine against norovirus by piggybacking on the highly effective vaccines for rotavirus, an unrelated virus that also causes diarrhea.

The researchers created an experimental rotavirus-norovirus combo vaccine by adding a key protein from norovirus to a harmless strain of rotavirus. Mice that received the experimental vaccine produced neutralizing antibodies against both rotavirus and norovirus. The study, available online in Proceedings of the National Academy of Sciences, outlines an innovative approach to preventing one of the most common and intractable viral infections.

Research – How to deal with food poisoning while traveling—and how to avoid it altogether

National Geographic

Some countries have a reputation for putting travelers at a higher risk for gastrointestinal illnesses. But you can get sick from an improperly handled meal anywhere in the world.

Pad thai from a Bangkok street vendor or raw milk cheese from a bistro in France taste delicious in the moment. But for many travelers, the local dishes that make trips meaningful sometimes give them food poisoning—and the wrong sort of vacation memories.

By some metrics, gastrointestinal infections related to food or water affect 30 to 70 percent of all travelers during or immediately after their trips, according to a 2015 study in BMJ Clinical Evidence. Each year, one in six Americans and nearly one in 10 people worldwide suffer from such illnesses caused by bacteria (E. coli, salmonella, listeria), viruses (norovirus, hepatitis A), or parasites (giardiasis, roundworms, tapeworms).

Lower-income countries have a reputation for putting travelers at a higher risk for food poisoning, but people are just as likely to be sickened from an improperly handled meal in Italy or Australia—or from some sushi at their local supermarket.

Here’s why people get food poisoning, what to do if it strikes, and how to (maybe) prevent it, read at the link above.