Norovirus Outbreaks
A norovirus outbreak is defined as an occurrence of two or more similar illnesses resulting from a common exposure that is either suspected or laboratory-confirmed to be caused by norovirus.
Current Outbreaks
There are no open investigations.
Previous Outbreaks
CDC is working with the U.S. Food and Drug Administration (FDA), the Texas Department of State Health Services, along with other state and local officials to investigate a multistate norovirus outbreak linked to raw oysters from harvest area TX 1, Galveston Bay, Texas.
The Texas Department of State Health Services and the Florida Department of Health notified the FDA of illnesses associated with eating raw oysters harvested from TX 1, Galveston Bay, Texas. On December 8, 2022, the Texas Department of State Health Services issued a recall on all oysters harvested between 11/17/2022 and 12/7/2022 from harvest area TX 1, Galveston Bay, Texas. They also informed the Interstate Shellfish Sanitation Conference who notified other member states. This resulted in other states initiating recall measures consistent with the Interstate Shellfish Sanitation Conference agreement.
As of April 11, 2023, 322 norovirus illnesses have been reported from 7 states. Restaurants and retailers in Tennessee (TN) received raw oysters harvested in area TX 1, but no illnesses were reported from TN. CDC is working with state and local partners to determine a more accurate number of illnesses in this outbreak and will update this number as more information is gathered.
Norovirus is the leading cause of foodborne illness in the United States. However, state, local, and territorial health departments are not required to report individual cases of norovirus illness to a national surveillance system. That’s why we may not know about many cases, especially if people do not go to a doctor’s office or hospital. Each year, there are about 2,500 reported norovirus outbreaks in the United States. Norovirus outbreaks occur throughout the year but are most common from November to April.
State and local public health officials are interviewing people about the foods they ate a day to four days before they got sick. In interviews, many of the sick people reported eating raw oysters.
State and local officials have collected information about the source of oysters from restaurants where sick people ate. FDA has confirmed that potentially contaminated raw oysters were harvested in area TX 1, Galveston Bay, Texas. The FDA and the states are conducting a trace forward investigation to determine where the raw oysters were distributed and to ensure they’re removed from the food supply.
This investigation is ongoing. CDC will update the public as more information is gathered.
This investigation is closed. Stay up to date on food recalls and outbreaks to avoid getting sick from eating contaminated food.
The Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), along with the Public Health Agency of Canada (PHAC), the Canadian Food Inspection Agency, and state and local partners, investigated a multistate outbreak of norovirus illnesses linked to raw oysters from British Columbia.
Illnesses: 192 illnesses* have been reported as of June 1, 2022
States affected: CA, CO, FL, HI, IL, MA, MN, NJ, NV, NY, OR, TX and WA
Recall: No
Investigation Status: Active
*This number is an estimate based on the information we have at this time. CDC is working with state and local partners to determine a more accurate number of illnesses in this outbreak and will update this number as more information is gathered.
If eaten raw, oysters and other filter-feeding shellfish can contain viruses and bacteria that can cause illness or death. Anyone who consumes raw shellfish is at risk of contracting norovirus. Children younger than five years old, the elderly, and those people with weakened immune systems are more likely to have severe infections. Food contaminated with norovirus may look, smell, or taste normal. To avoid food poisoning from oysters, cook them well to a temperature of at least 145 degrees F.
Do not serve or sell raw oysters harvested from the following harvest locations (or landfiles) within the south and central parts of Baynes Sound, British Columbia, Canada:
- Retailers should not serve raw oysters harvested from the following harvest locations within British Columbia: BC 14-8 and BC 14-15, with harvest starting as early as January 31, 2022, which will be printed on product tags.
- The FDA has confirmed that potentially contaminated raw oysters harvested in the south and central parts of Baynes Sound, British Columbia, Canada, were distributed to restaurants and retailers in CA, CO, FL, HI, IL, MA, MN, NJ, NV, NY, OR, TX, and WA. It is possible that additional states received these oysters through further distribution within the U.S.
Throw away any remaining oysters or return them to your distributor for destruction.
These oysters may be contaminated with norovirus. Follow these steps:
- Wash and sanitize containers and surfaces that may have come into contact with these oysters.
- Wash hands with warm water and soap following the cleaning and sanitation process.
Do not eat any raw oysters from the areas listed above. If you have oysters at home from any of the areas listed above, throw them away. Clean any utensils or food preparation surfaces that may have touched the oysters.
If you think you might have gotten sick from eating possibly contaminated raw oysters, talk to your healthcare provider and report your illness to your local health department.
The most common symptoms are:
- Diarrhea
- Vomiting
- Nausea
- Stomach pain
- A person usually develops symptoms 12 to 48 hours after being exposed to norovirus. Most people with norovirus illness get better within 1 to 3 days.
- With this illness, there is a risk of dehydration, so call a healthcare provider right away if young children, older people, or anyone getting sick seems dehydrated.
- Cook oysters and other shellfish thoroughly before eating them (at least 145 degrees); quick steaming is not enough.
- Wash your hands thoroughly with soap and water often.
- Carefully wash fruits and vegetables before preparing and eating them.
- Do not prepare food or care for others when you are sick, and for at least two days after symptoms stop.
- Clean and disinfect contaminated surfaces. Wash contaminated laundry thoroughly.
CDC is working with the U.S. Food and Drug Administration (FDA) state, and local officials, and with Canadian public health authorities to investigate a multistate norovirus outbreak linked to raw oysters from British Columbia, Canada.
As of June 1, 2022, 192 norovirus illnesses have been reported from 13 states: CDC is working with state and local partners to determine a more accurate number of illnesses in this outbreak and will update this number as more information is gathered. FDA Advises Restaurants and Retailers Not to Serve or Sell Potentially Contaminated Raw Oysters from Canada (April 2022)
Norovirus is the leading cause of foodborne illness in the United States. However, state, local, and territorial health departments are not required to report individual cases of norovirus illness to a national surveillance system. That’s why we may not know about many cases, especially if people do not go to a doctor’s office or hospital. Each year, there are about 2,500 reported norovirus outbreaks in the United States. Norovirus outbreaks occur throughout the year but are most common from November to April.
State and local public health officials are interviewing people about the foods they ate a day to four days before they got sick. In interviews, many of the sick people reported eating raw oysters.
State and local officials have collected information about the source of oysters from restaurants where sick people ate. FDA has confirmed that potentially contaminated raw oysters were harvested in the south and central parts of Baynes Sound, British Columbia, Canada. The FDA and the states are conducting a trace forward investigation to determine where the raw oysters were distributed and to ensure they’re removed from the food supply.
This investigation is ongoing. CDC will update the public as more information is gathered.