December 8, 2004

It is Norwalk virus season

NEWMARKET York Region Health Services advises residents that the Norwalk virus is circulating in the community. This illness can occur year round, but it is more common in the fall and winter. The virus is contagious so it is important to take proper precautions to prevent the spread of infection.
Norwalk virus is a very common cause of diarrhea and vomiting in humans. The usual symptoms are sudden onset of watery diarrhea, vomiting, cramps, headache, fever, chills and sore throat. These symptoms usually appear 24 to 48 hours after having contact with the virus.  The illness commonly lasts 24 to 48 hours. Immunity against the virus can last up to 14 weeks.
The Norwalk virus infects humans only, and spreads through exposure to infected people or contaminated food or water. The virus is passed in stool and in vomit. Outbreaks have been linked to sick food handlers, contaminated shellfish, or water contaminated with sewage. Direct contact or airborne transmission during vomiting has been suggested to explain the rapid spread in institutions. The virus is very contagious and only a few viruses are needed to cause illness.
Norwalk viruses are often associated with outbreaks in long term care facilities, homes for the aged and other adult institutions due to the close proximity of the residents. Outbreaks have also been linked to banquet halls, cruise ships, swimming pools, schools and restaurants.
There is no specific treatment available.  Drink liquids frequently to avoid becoming dehydrated.
How do you prevent Norwalk infections?
 Wash hands thoroughly after using the toilet, handling diapers or before preparing food.
 Clean and sanitize washrooms and all hand contact surfaces once daily or as needed.
 Avoid drinking untreated water.
 Cook shellfish thoroughly before eating.
For more information on the Norwalk virus or other health-related questions, contact York Region Health Services Health Connection at 1-800-361-5653 or visit

Contact:  Kim Clark, York Region Health Services
   905-841-3606 Ext. 4101

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