Raw Oysters & Clams Recalled in 9 States Due to Norovirus Risk | Healio

The Food and Drug Administration (FDA) this week warned consumers and retailers about recalled raw oysters and clams potentially contaminated with norovirus, impacting at least nine states. The shellfish were harvested from Washington’s Drayton Harbor between February 13 and March 3, raising concerns about foodborne illness linked to the region’s shellfish harvesting practices.

Potential Exposure and Geographic Reach

The recall affects oysters distributed solely within Washington state. However, the implicated clams were shipped to a wider geographic area, including Arizona, California, Florida, Georgia, Illinois, Nevada, New York, Oregon, and Washington. The FDA also noted the possibility of further distribution to other states, urging consumers nationwide to exercise caution. The oysters were harvested by Drayton Harbor Oyster Company, while the Lummi Indian Business Council harvested the clams.

The Washington Department of Health initially alerted the FDA on March 4, reporting a norovirus-like illness outbreak associated with raw oyster consumption. This prompted the FDA to advise restaurants and food retailers to immediately dispose of any remaining products, either through garbage disposal or by coordinating destruction with their distributors.

Understanding Norovirus and the Risk

Norovirus is a highly contagious virus that causes gastroenteritis – inflammation of the stomach and intestines. Symptoms typically include diarrhea, vomiting, nausea, and stomach pain. While most individuals recover within 12 to 48 hours, the illness can be more severe for children, older adults, and individuals with compromised immune systems, according to the Centers for Disease Control and Prevention (CDC). CDC information on Norovirus provides detailed guidance on prevention and symptoms.

Carlota Medus, PhD, MPH, an epidemiologist with the Minnesota Department of Health, explained that the likely source of contamination is human waste entering the water supply where the shellfish were harvested. “Bivalve mollusks are filter feeders, so anything that is in the water, including pathogens that cause human illness, can end up inside the oyster or mollusk,” she told Healio. “When you eat them raw, they can build you sick. Norovirus outbreaks associated with oysters are not rare.”

It’s important to note that food contaminated with norovirus often appears, smells, and tastes normal, making detection difficult without laboratory testing. This underscores the importance of adhering to the FDA’s recall guidance and avoiding consumption of potentially contaminated shellfish.

Filter Feeders and Contamination Pathways

The vulnerability of oysters and clams to contamination stems from their feeding mechanism. As filter feeders, these shellfish continuously draw water through their systems to extract nutrients. Unfortunately, this process also means they can accumulate viruses, bacteria, and other pathogens present in the surrounding water. The FDA provides detailed information on shellfish safety, including potential contaminants and monitoring programs.

Human sewage, whether from failing septic systems, wastewater treatment plant overflows, or recreational water activities, can introduce norovirus into coastal waters. Factors like rainfall, tidal patterns, and proximity to population centers can influence the level of contamination. Regular monitoring of shellfish harvesting areas is crucial to identify and mitigate these risks.

Norovirus: A Leading Cause of Foodborne Illness

Norovirus is the leading cause of vomiting, diarrhea, and foodborne illness in the United States, causing approximately 2,500 reported outbreaks annually. Most infections occur through direct contact with an infected person, but contaminated food, including raw shellfish, is a significant source of outbreaks. The CDC estimates that norovirus causes 14 to 17 million illnesses, 145,000 hospitalizations, and 146 deaths each year in the US. Healio reports on the leading causes of foodborne illness, highlighting the prevalence of norovirus.

Public Health Response and Ongoing Monitoring

The FDA is working with state and local health authorities to investigate the outbreak and assess the extent of the contamination. This includes tracing the distribution of the recalled shellfish and conducting environmental sampling to identify the source of the norovirus. The agency will continue to provide updates as more information becomes available.

State health departments play a critical role in monitoring shellfish harvesting areas and implementing control measures to prevent contamination. These measures may include temporary closures of harvesting areas, increased water quality testing, and improved wastewater management practices.

What to Do If You Suspect Illness

Individuals who have consumed raw oysters or clams from Drayton Harbor between February 13 and March 3 and are experiencing symptoms of norovirus should consult a healthcare professional. While there is no specific treatment for norovirus infection, supportive care, such as hydration, can assist manage symptoms. It’s also important to practice excellent hygiene, including frequent handwashing, to prevent the spread of the virus to others.

The FDA advises consumers to stay informed about recalls and safety alerts by visiting the agency’s website and subscribing to email notifications. The FDA’s alerts and advisories page provides the latest information on food safety issues.

Carlota Medus, PhD, MPH can be reached at [email protected].