A new strain of norovirus called GII.4 Sydney is currently spreading rapidly across the United States. First identified in Australia in March, the highly contagious intestinal strain is infecting people worldwide and has recently become the leading cause of all new U.S. viral outbreaks.
What is norovirus?
Often confused with the ‘stomach flu,' norovirus is a common form of viral gastroenteritis that according to the Centers for Disease Control and Prevention (CDC) affects more than 21 million people in the United States each year. Originating in the stomach and intestinal tract, the disease causes inflammation of the tissues leading to acute episodes of nausea, vomiting and diarrhea. Symptoms are usually accompanied by abdominal pain and in some instances norovirus can also cause muscle aches, lethargy, headache and even low-grade fever.
Infection comes on suddenly, with people developing symptoms within 24 to 48 hours of exposure. People infected with norovirus are contagious as soon as they become sick and remain contagious up to three days after they recover. The virus may last a few days, although for the very young, the elderly, or people with compromised immune systems, the disease can lead to more severe problems that can require medical attention.
According to the CDC,
'Norovirus is estimated to cause over 70,000 hospitalizations and 800 deaths each year in the United States.'
Unlike influenza, with which it is often confused, norovirus infection does not provide immunity. Other than supportive care there are currently no treatments available, although some promising results have come from human clinical trials conducted on a dry powder intranasal vaccine by the Montana-based research company, LigoCyte Pharmaceuticals. If a viable vaccine should be developed, the challenge would lie in figuring out how long the protection would last.
How does norvirus differ from the flu?
Often referred to as the ‘stomach flu,’ norovirus is not the same as influenza, although symptoms can overlap. The primary difference between the two is influenza is a virus of the respiratory tract while norovirus originates in the stomach and intestines. Common symptoms of the flu may include 'stomach flu'-like ailments; nausea, vomiting and diarrhea, but these are secondary to the illness and not the primary source of infection.
How do you get norovirus?
The most common way to contract norovirus is through person-to-person contact, which according to the CDC currently accounts for over half of all norovirus infections. Areas of concentrated populations such as cruise ships and long-term care facilities are most widely affected as their closed and crowded environments provide fertile ground for the virus to spread rapidly.
Another way to contract norovirus is through contaminated food or water. However, while norovirus is a major cause of ‘food poisoning,’ there are many other germs and chemicals that can bring about the ailment. Foods most commonly associated with norovirus outbreaks include shellfish, leafy greens and fresh fruit. The CDC estimates that food-borne outbreaks currently account for 20 % of reported norovirus cases.
A smaller source of infection can be attributed to contaminated surfaces, which when touched by the hands can transmit the virus to the body. While not all chemicals are effective in eradicating the norovirus from hard surfaces, the virus can be effectively killed by chlorine-based disinfectants.
What can you do?
Norovirus, while highly unpleasant, is not usually serious and quickly runs its course in one to two days.
If you contract norovirus, make sure to keep hydrated. Vomiting and diarrhea deplete the body of essential fluids which can lead to further complications. Drink plenty of liquids and consider oral rehydration therapy if the dehydration is severe.
To combat the potential for person-to-person contact, wash hands often and do not eat food prepared by anyone who has the virus. Clean and disinfect surfaces to prevent foodborne illness. Lastly, do not prepare food while infected.
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