If you have '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.

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.