NORWALK VIRUS

1. NORWALK VIRUS By: Channing Cox

2. TRANSMISSION • Humans are the only source for these viruses. • These viruses do not multiply outside the human body. • The viruses are present in the feces of infected persons and can be transmitted to others when hands are not thoroughly washed after having a bowel movement. • When food that is not later cooked is handled by an infected person who did not wash hands after toileting, others who eat the food can become infected. • People also can be infected by drinking water contaminated by sewage containing one of these viruses or by consuming ice made from contaminated water. • There is some evidence that the viruses can be transmitted by aerosolized vomitus.

3. SYMPTOMS • The signs and symptoms of Norwalk-like viruses are similar and usually occur between 24 hours and 48 hours after exposure. • They include nausea, vomiting, diarrhea, abdominal pain, muscle aches, headache, tiredness and low-grade fever. • Symptoms typically last 24 hours to 48 hours and subside on their own.

4. PREVALENCE • The U.S. Centers for Disease Control and Prevention estimates that more than 180,000 cases of Norwalk-like virus infections occur annually in the United States. • Some studies indicate that more than 60 percent of the U.S. population is exposed to one or more of these viruses by the age of 50.

5. PREVENTION • Food handlers should practice careful hand washing after having a bowel movement, especially when handling food that will not be cooked later. • Water supplies should be protected from the risk of contamination by sewage. • Plumbing in dwellings and business establishments should be constructed with no cross-connections to prevent sewage from entering the drinking water supply.

6. TREATMENT • Oral fluid and electrolyte replacement is generally adequate for the treatment of Norwalk Virus. • In cases of severe volume depletion, intravenous fluid and electrolyte resuscitation may be necessary. • Symptomatic relief can be achieved using antiemeticsfor nausea and vomiting and analgesics for myalgias and headache.

7. STRUCTURALFEATURES • There are really no certain structural features that help enhance the ability to cause a disease. • Although, the ability of the virus to survive relatively high levels of chlorine and varying temperatures help enhance its ability to cause disease. • Because of the diversity of NLV strains, lack of complete cross-protection, and lack of long-term immunity, repeated infections can occur throughout life.

8. ENVIRONMENTAL IMPACT • Norwalk virus - is highly contagious and often spreads in places like schools, cruise ships and nursing homes, especially during the winter. • Infected people usually recover in 2 to 3 days without serious or long-term health effects.

9. GLOBAL IMPACTS • In January 2013, the US Centers for Disease Control and Prevention (CDC) reported that a new norovirus strain, GII.4 Sydney, which was first detected in Australia, had spread to the United States. • During the last 4 months of 2012, GII.4 Sydney accounted for 53% of 266 norovirus outbreaks in the United States, with roughly half of them having resulted from direct person-to-person transmission and another 20% having been foodborne. • The virus affects around 267 million people and causes over 200,000 deaths each year; these deaths are usually in less developed countries and in the very young, elderly and immuno-suppressed.