Norovirus

What is norovirus?

Norovirus is a very common virus that causes diarrhea and vomiting in humans. Noroviruses are named after the original Norwalk virus and Norwalk-like viruses. The viruses are very small and often difficult to detect. Noroviruses are commonly responsible for outbreaks in places where people are in close proximity to each other. Such places include nursing homes, homes for the aged, banquets, cruise ships, swimming pools, childcare centres, schools, and restaurants.

How does a person get norovirus infection?

Humans are the only known reservoir for the norovirus therefore noroviruses are transmitted person to person. Noroviruses can also be transmitted through food. The “fecal-oral” route is the primary mode of transmission, although environmental contamination and aerosolization of the virus help explain the rapid spread in a group setting. Noroviruses are very contagious and only a few are needed to cause illness.

What are the symptoms?

Symptoms usually have a sudden onset and include watery non-bloody diarrhea, vomiting, abdominal cramps and nausea. A low-grade fever may occur and dehydration is possible. The illness usually lasts 24 to 48 hours; however, the norovirus can still be spread for up to 48 hours after the symptoms stop. These symptoms usually appear 24 to 48 hours after exposure to the virus.

How can you prevent norovirus infection?

Thorough hand washing is the best prevention. Make sure hands are properly washed after using the toilet, changing diapers, and before preparing or eating food.

• People ill with diarrhea and other norovirus symptoms should be isolated from others;
• Wash your hands when entering and leaving a healthcare facility or daycare setting;
• Carefully dispose of feces, and any materials contaminated with feces and/or vomit;
• Clean and sanitize washrooms and all hand contact surfaces once daily or as often as needed; and
• In long term care institutions, isolate ill residents from group activities until they are symptom free for 48 hours. Ill staff should remain off work until symptom free for 48 hours.

For more information please contact 1-800-958-6400 or the local Public Health Nursing Office.