If you have a 'stomach flu,' chances are it's actually norovirus: What you should know

If you’ve ever gotten sick from eating something “bad,” you may have had an encounter with norovirus.

Sometimes called a “stomach bug” or “stomach flu” — though it’s not related to the flu — norovirus is the leading cause of foodborne illness in the United States, causing between 19 million and 21 million cases of infectious vomiting and diarrhea each year.

Norovirus outbreaks can affect anyone, anywhere. Earlier this month, for example, a cruise trip was cut short after 475 passengers became ill with the infection, which spread more easily due to the confines of the ship.

What is norovirus?

Norovirus is a highly contagious virus that causes gastroenteritis, which is inflammation in the stomach and intestines. It can infect people of all ages, and an infection can occur multiple times because there are many different strains of norovirus.

People who come down with an infection may experience symptoms like abdominal pain, nausea, vomiting and diarrhea. Usually, these symptoms develop within 12 to 48 hours after exposure and go away within one to three days. However, children, older adults and people with other illnesses are susceptible to more severe symptoms since they are at risk for dehydration from the infection.

Outbreaks can happen year-round but are more frequent from November to April.

How can you get Norovirus?

Norovirus is transmitted by any kind of contact that causes the virus to enter the mouth. You can pick it up directly from contact with another person, by touching an infected surface and then touching your mouth or by eating contaminated food or water. It’s frequently found in places where there are a lot of people, and the most common places for outbreaks to occur are health care facilities, restaurants and schools or daycare centers. Cruise ships account for only 1 percent of overall outbreaks.

How to prevent and treat a norovirus infection

If you think you have symptoms of a possible infection, rest and drink plenty of fluids. Antibiotics cannot help because the infection is viral — antibiotics only work on bacterial infections. Most importantly, avoid contact with other people and make sure to wash your hands often.

Also clean any dirty clothes, making sure to handle soiled items with care. Do not prepare food for others and disinfect any contaminated surfaces with bleach. You are contagious from the moment you start feeling sick to the first few days after you recover. If you suspect an outbreak in your community, you should also contact your state or local health department.

Dr. Tiffany Truong is a resident physician in internal medicine in Houston and a member of the ABC News Medical Unit.