How long is the stomach flu contagious cdc

Norovirus includes a group of viruses that cause “stomach flu” or gastroenteritis in people. Individuals may become very sick with acute vomiting and diarrhea lasting 1-2 days. These viruses are the most common cause of food-borne outbreaks. This virus is extremely contagious and can spread rapidly through congregated facilities such as day-care, long term care and school environments. The virus can spread person-to-person, through contact with surfaces in the environment and through contaminated food and beverages.

Resources for Maine Residents:

• Norovirus fact sheet (PDF)
• Federal CDC Norovirus
• Norovirus on cruise ships
• US EPA guidance on cleaning agents for norovirus (PDF)

Resources for Healthcare Providers:

• Norovirus Outbreak Surveillance Reports 2011 (PDF) | 2012 (PDF) | 2013 (PDF) | 2014 (PDF) | 2015 (PDF)
• Maine CDC Norovirus Outbreak Guidance for Long Term Care (Word)
• Maine CDC Norovirus Outbreak Checklist (Word)
• CDC Updated Norovirus Outbreak Management and Disease Prevention Guidelines 2011 (PDF)
• Health and Environmental Testing Laboratory - Sample Submission
• Federal CDC - Norovirus in Health Care Settings
• Norovirus in Healthcare Facilities Fact Sheet (PDF)
• CDC HICPAC Guideline (PDF) for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings

It is important to drink plenty of fluids lost through vomiting and diarrhea to avoid dehydration. Antibiotics are not effective in treating norovirus. Time, rest and avoiding contact with others is important. See a doctor or go to an urgent care walk-in clinic if you or someone you are caring for seems dehydrated. For additional information go to www.cdc.gov

Norovirus goes by many different names: winter vomiting bug, food poisoning and stomach flu among them. Like influenza, norovirus is caused by a virus, and it is a very common infection that affects millions of people each year. 

So, what is it? A norovirus infection affects the stomach and intestines and can cause vomiting and diarrhea. Norovirus is a very contagious disease and takes between 12 to 48 hours to incubate and start showing symptoms. Because a virus causes it, antibiotics will not help treat it. 

Dr. Edwin Yu is an infectious disease specialist at Banner – University Medical Center Phoenix. He describes it as serious from a population health standpoint as it is very contagious leading to major outbreaks.

“Think of a cruise ship where it can spread quickly and affect a large proportion of the passengers,” Dr. Yu said. 

According to the Centers for Disease Control and Prevention, norovirus outbreaks can happen any time during the year, but most of the time, people get it from November through April. In the United States, the CDC estimates that each year norovirus:

• Causes 19 to 21 million cases of acute viral gastroenteritis
• Leads to 1.7 to 1.9 million outpatient visits and 400,000 emergency department visits
• Contributes to 56,000 to 71,000 hospitalizations and 570 to 800 deaths, mostly among young children and the elderly

Norovirus symptoms

When you get norovirus, telltale symptoms start showing up shortly after getting infected. According to the CDC, common symptoms include diarrhea, vomiting, nausea and stomach pain. Additionally, some people may have a fever, headaches and body aches.

“Typically, symptoms run for 1-3 days,” Dr. Yu said. “That said, even after infected individuals recover they can still shed the virus in their stool for a few weeks.”

As Dr. Yu and the CDC note, norovirus can spread quickly. The CDC’s website states, “You can get norovirus by accidentally getting tiny particles of poop or vomit from an infected person in your mouth.”

How does this happen? Three primary ways:

• You eat food or drink liquid contaminated with norovirus.
• You touch contaminated things—a countertop or doorknob, for example—and then put your fingers in your mouth.
• You have direct contact with someone who is infected with norovirus. This could be something as simple as caring for them or sharing food or eating utensils with them.

Typically, people are contagious with norovirus when they have active symptoms—particularly vomiting. You also can be very contagious for the first few days after you recover from norovirus. The CDC notes studies have shown people remain contagious for two or more weeks after they feel better.

Plus, you can always get norovirus from contaminated food or water, which is why it is one of the main causes for food poisoning. It only takes a small amount of the virus to get you sick. Food and water become contaminated when an infected person with dirty hands touches the food. It can also happen when the food sits on a counter that has norovirus on it. Or, the food was grown using contaminated irrigation water.

Norovirus prevention

Cleanliness is important to beating norovirus. To prevent getting it, practice good hand hygiene—meaning wash your hands thoroughly—and properly clean your food before eating it.

“Wash your hands with soap and water,” Dr. Yu said. “It is resistant to alcohol, so therefore, alcohol-based hand gels will not work.”

Be sure to wash your hands after each time you use the toilet, change a diaper, before you prepare food and when you give someone medicine. 

With fruits and vegetables, make sure to clean them thoroughly before eating them. If you suspect they have been contaminated with norovirus, you should throw them away. According to the CDC, norovirus can survive heat as high as 145 degrees Fahrenheit and quick steaming.

If you are sick, you should not prepare food or care for others. In fact, the CDC says a lot of people infected during an outbreak likely got the disease from restaurants. And, if your job requires you to prepare food for others, do not plan on touching the food for at least two days after your symptoms have stopped.

Also consider disinfecting surfaces after someone vomits or has diarrhea. This can prevent norovirus particles from living on different surfaces until someone else touches them. Always use a cleanser the Environmental Protection Agency has identified as effective against norovirus.

Finally, make sure you wash your laundry thoroughly. The CDC recommends:

• Handling any soiled items carefully. You should consider wearing rubber or disposable gloves when handling dirty laundry from a sick person
• Washing the items with detergent and hot water. Run the wash with the longest cycle length and then machine dry them

Norovirus treatment

Dr. Yu says there is no specific treatment, and he notes it is important to stay hydrated and replenish electrolytes lost from the vomiting and diarrhea. You can drink Pedialyte, an oral rehydration solution, sports drinks or other electrolyte-rich liquids.

Signs of dehydration include:

• A decrease in urination
• A dry mouth and throat
• Dizziness when standing up

Dehydration can lead to serious complications and, if it gets severe, can put you in the hospital. If you or someone you know appears to be dehydrated, call the doctor.

Dr. Yu’s final piece of advice for norovirus is to remember it is very contagious, and infected individuals should not handle or prepare food even for several days. He adds that norovirus is certainly a valid reason to not cook for others and for calling in sick to work.

“It is a significant nuisance,” Dr. Yu said. “If you ever had it, you would remember it because of all the vomiting and diarrhea.”

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