Norwalk Virus

Agenda

• Norwalk History• How Does Norwalk Virus Work• How is the Virus transmitted• Signs and Symptoms• Norwalk Statistics• Therapy / Treatment• Preventative Measures

Norwalk History

• Norwalk virus was identified in 1972 after an outbreak of gastrointestinal illness in Norwalk, Ohio.

• Other viruses with similar features were described and are called Norwalk-like viruses.

How Does Norwalk Virus Work

• The virus attaches to the outside of cells lining your intestine. Then it transfers its genetic material into that cell.

• The cell reproduces, finally killing the human cell to release new copies of it that attach to more cells of your intestine's lining.

How is the Virus transmitted?

• These type of viruses are generally transmitted via contaminated food.

• Virus is shed in large numbers in the vomit and stool of infected individuals, most commonly while they are ill.

• Individuals may continue to shed virus after they have recovered from the illness.

• Norwalk virus may also be spread from person-to-person – reinfection can occur.

•Normally develops 24 - 48 hours after exposure.

•Headache / Vital signs are usually normal

•Abdominal Pain

•Mild fever in contrast to bacterial gastroenteritis

•1 - 5 days of watery diarrhea prominently associated with nausea and vomiting

Signs and Symptoms

•Tachycardia (Increased Pulse Rate) and hypotension (Low Blood Pressure) associated with severe dehydration

•Death can result from dehydration and acidosis

Signs and Symptoms

• In the United States:

•3.5 million cases/yr. in infants leading to 500,000 office visits and 30 deaths

•9.2 million cases (of 12.7 mil.total)/yr. of food-related illness

Norwalk and Norwalk Like Virus Statistics

•In the US:

• 12.7 million cases

•International:

• 200 million cases

•12.7 million cases x 4 episodes/day x 3 days duration x 200ml/episode = 3.6x1011 ml of diarrhea or 105 million gallons or 6 minutes of flow over Niagra Falls

Just How Much Diarrhea is That?

• Generally self-limiting /No specific treatment

• Oral rehydration with electrolyte solution esp. with children

• Intravenous (IV) treatment in severe dehydration

Therapy / Treatment

Preventative Measures

• Norwalk does not multiply in foods as many other bacteria do

• Thorough cooking destroys this virus• Shellfish (oysters, clams, mussels)

pose the greatest risk and any particular serving may be contaminated; there is no way to detect a contaminated oyster from a safe oyster.

Preventative Measures

• If you travel and an area appears it could have polluted water etc. drink only boiled drinks or bottled water etc.

• Exclude people that are sick from the kitchen

• Wash hands with soap and warm water