What is Norovirus

Norovirus Magnified

Norovirus Magnified

Norovirus is the name given to a virus now known to be one of the main causes of gastroenteritis food poisoning. In reality, the term is applied to a number of similarly constructed viruses which also cause stomach and intestinal inflammation that in turn induces nausea vomiting and diarrhea.  It was originally called the Norwalk virus, after the Ohio town of that name where it was first identified.  Researchers had taken the opportunity provided by an outbreak of stomach problems. In the Norwalk elementary school, to follow through on previous studies, and prove what was long suspected, that a virus can be responsible for gastroenteritis problems.

Today it is recognized that Norovirus is one of the major causes of gastroenteritis outbreaks and isolated, individual instances as well.  The outbreak in Norwalk occurred in 1968 but it wasn’t until 1972 that the virus had been isolated.  A big factor in the researcher’s success had been the use of Immune Electron Microscopy, a technique, developed in the early 1940′s that made it possible to examine much smaller items than use of  traditional microscopes allowed.  However, while IEM technology made identifying the virus possible, human volunteers were still required to show the virus was actually the cause of the outbreak.

Dehydration is the biggest danger of Norovirus
The Norovirus is just one cause of food poisoning. Food borne illnesses can also be caused by bacteria, parasites, natural toxins, chemical toxins, and allergens.  The severity of a food borne illness will vary greatly depending on the person who has it and the cause. Norovirus is not usually life threatening to otherwise healthy people, but it does claim between five hundred and eight hundred lives in the United States annually.  Most of the victims are either young children or older adults.  The real danger for those suffering from Norovirus is the possibility of dehydration, which is always a concern when diarrhea and vomiting are suffered for any length of time.

Sanitation and hygiene are the keys to controlling Norovirus.
The Norovirus is often associated with cruise ships because of some well publicized out breaks that have occurred.  In fact outbreaks have been reported on twelve different cruise ships in the last five years. This is because ships are a closed environment and closed environments are readily susceptible to Norovirus outbreaks. Schools, hospitals, day care centers and nursing homes are all environments where the Norovirus could spread rapidly if not kept in check by good sanitation and hygiene practices.

Norovirus is spread through contaminated food, infected fecal matter or vomit, by contact with an infected person or by coming in contact with an infected source like food dishes or utensils and food surfaces.  The following practices, if followed faithfully, can help to reduce the spread of Norovirus

• Infected food service workers should not return to work for at least two days after their symptoms have ceased. A person can still be contagious for as long as a week after signs of the virus have passed.

• Thorough hand washing should be practiced by everyone but especially food service workers. This can include sanitizers, but soap and hot water are required as well.

• Food surfaces that may have been contaminated should be washed with a 5%-25% bleach solution. If a pre-mixed cleanser is used be sure it is labeled as effective against Norovirus.

• Food handlers should wear proper gloves to avoid infecting hand food such as sandwiches.

• Clothes or other fabrics that may have been exposed to the virus should be machine washed and machine dried.

• Fruits and vegetables should be washed thoroughly.

• Shellfish must be cooked thoroughly. The Norovirus is capable of living in temperatures up to 140 degrees Fahrenheit.

Norovirus is usually identified by its symptoms of diarrhea, vomiting, and nausea, and can last one to three days. There is no anti-viral medication for Norovirus and the disease just usually runs its course.  It is possible to identify it by testing stool samples but this is not routinely done.  A person who has experienced Norovirus will be likely to develop immunity to the specific strand by which he or she was infected, but will not be protected from similar strains.

Although the Norovirus is a factor in relatively few deaths each year, it is responsible for as many as twenty one million illnesses annually and anywhere from 50,000-70,000 hospitalizations. If the danger of dehydration is taken seriously and dealt with effectively, the dangers of Norovirus are minimal.  Food handlers, however, play the key role in limiting its spread.

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