By Amir Mohammad
Public Health
Dr. Amir Mohammad
If you’ve been keeping up with the non-political news lately, you may have noticed a surge in norovirus cases across the US. For many, the term “norovirus” brings to mind outbreaks of diarrheal illness on cruise ships. However, these recent outbreaks are occurring in a variety of settings and are not confined to the ocean.
At least 80 people became ill in December after consuming raw oysters linked to a norovirus outbreak at a restaurant event in Los Angeles. The oysters, sourced from British Columbia, Canada, were distributed to 14 states and the District of Columbia before being recalled. Following the outbreak, the Food and Drug Administration issued a warning advising against eating these contaminated oysters.
Norovirus is a highly contagious virus responsible for 58 percent of foodborne illnesses in the US. It spreads rapidly through contaminated food, surfaces or direct contact with infected individuals. It causes symptoms such as nausea, vomiting, diarrhea, stomach pain, fever and body aches.
Dr. William Schaffner, a professor of infectious diseases at Vanderbilt University School of Medicine, explains that norovirus is exceptionally contagious due to two key factors: its ease of transmission and its resilience on surfaces, where it can survive for days or even weeks. People can become infected through contact with an infected individual, consuming contaminated food or water or touching contaminated surfaces. This high transmissibility makes norovirus particularly problematic in crowded, indoor environments such as cruise ships, nursing homes, schools and day care centers.
Research has highlighted that contaminated water, especially untreated sewage, can introduce norovirus into the food supply via irrigation. Shellfish like oysters and mussels are frequently implicated in outbreaks since they filter water to feed, accumulating concentrated levels of bacteria and viruses in their tissues.
Good hand hygiene is the best line of defense against norovirus, but relying solely on hand sanitizers isn’t enough. According to Schaffner, the virus’s structure makes it less vulnerable to alcohol-based sanitizers and wipes. Washing hands with soap and water for at least 20 seconds is significantly more effective at removing the virus. The Centers for Disease Control and Prevention particularly advises handwashing after using the restroom, changing diapers, before preparing food or administering medication.
There is currently no antiviral treatment for norovirus infections. Physicians typically advise patients to stay home from work or school and focus on staying hydrated by drinking plenty of fluids. Most cases of norovirus resolve on their own within a few days without the need for medical intervention.
Certain groups, including young children, older adults and individuals with weakened immune systems, are at greater risk of severe illness due to the likelihood of experiencing dehydration. Symptoms of severe dehydration can include fatigue, dizziness and irritability in children. In more serious cases, hospitalization may be required for intravenous fluid administration to restore hydration and prevent complications.
The rise in norovirus infections highlights the importance of food safety measures and vigilance in identifying and managing outbreaks to prevent further spread. The situation also underscores how easily this highly contagious virus can infiltrate food supplies and affect public health.
Dr. Amir Mohammad is the director of public health for the town of Orange.