A new strain of the highly contagious norovirus has reached the U.S. from Australia.
The U.S. Centers for Disease Control and Prevention (CDC) reports that the new norovirus, named GII.4 Sydney because it's believed to have started in Sydney, Australia, is the leading cause of norovirus outbreaks in the U.S.
In the CDC's Morbidity and Mortality Weekly Report released Jan. 25, the noroviruses are: the leading cause of epidemic gastroenteritis, including foodborne outbreaks, in the U.S. Hospitalization and mortality associated with norovirus infection occur most frequently among elderly persons, young children, and immunocompromised patients.
An article in Time, Health and Family reported that
- Norovirus is often confused with what many call "stomach flu" because of its contemporaneous circulation with influenza during winter months
- Norovirus causes 21 million cases of illness, often involving severe vomiting and diarrhea, 70,000 hospitalizations each year in the U.S., and 800 deaths.
- Where influenza is a respiratory illness, norovirus, which comes in five forms, favors the stomach and intestinal tract, causing inflammation of tissues that leads to pain, nausea, and the diarrhea and vomiting.
Time reports that the CDC says 51 percent of the cases in the U.S. were caused by person-to-person transmission, and 20 percent resulted from contaminated food.
Most infections occur in places where large numbers of people are gathered, such as schools, nursing homes and cruise ships, where the virus can pass easily from host to host.
In Australia, the CDC said long-term–care facilities and restaurants were the most frequently reported settings of the GII.4 Sydney outbreaks. The rate of infection increases in places where large numbers of people are gathered and the virus is passed quickly from host to host.
The CDC reports reports the new strain of norovirus was first identified in March 2012 in Australia and has since sickened people on several continents.
According to Time: Historically, the GII strains have caused more severe illness than other versions of the virus, but officials at the CDC says it is too early in the season to determine if GII.4 Sydney is infecting people at higher rates than in previous years. The norovirus season runs from November through March and cases typically peak in January.
“Although most of the time you recover after 24 or 48 hours, [norovirus] is a reason for people to come to the emergency room, and is even responsible for a small number of death each year. It’s not a completely innocuous virus and can certainly ruin a vacation,” Dr. John Treanor, chief of the Infectious Diseases Division at the University of Rochester Medical Center told Time.
So far, no treatments exist for the norovirus but Treanor told Time a group of scientists are currently testing a vaccine developed by LigoCyte Pharmaceuticals. The shot contains a part of the norovirus’ outer layer, which they hope will generate a strong immune response in those who get immunized.
Preventing infection with norovirus is similar to protecting against influenza.
The CDC recommends the following:
- Wash your hands carefully with soap and water, especially after using the bathroom or changing diapers and before handling food.
- Carefully wash produce and seafood before cooking and consuming them. Cook oysters and other shellfish thoroughly before eating them. Be aware that noroviruses are relatively resistant. They can survive temperatures as high as 140°F and quick steaming processes that are often used for cooking shellfish.
- When you’re sick, wait 2-3 days after you recover before preparing food for anyone. Many local and state health departments require that food handlers and preparers with norovirus illness not work until at least 2 to 3 days after they recover. If you were recently sick, you can be given different duties in the restaurant, such as working at a cash register or hosting.
- Immediately clean any infected or contaminated surfaces and wash laundry thoroughly after throwing up or having diarrhea. Immediately clean and disinfect contaminated surfaces. Use a chlorine bleach solution with a concentration of 1000–5000 ppm (5–25 tablespoons of household bleach [5.25 percent] per gallon of water) or other disinfectant registered as effective against norovirus by the Environmental Protection Agency (EPA).