nausea vomiting and diarrhea that comes on suddenly becomes severe then begins to get better within a few days is usually due to a viral gastroenteritis (an infection of the stomach and intestine by a virus). although the influenza virus can cause these symptoms “stomach flu” is almost always caused by other non-influenza viruses. sometimes bacteria such as salmonella may be responsible. people with viral gastroenteritis may continue to shed virus in their stool for weeks well after the time they feel better. it’s likely that they can easily pass the virus on to others during this time. it’s best to pay extra close attention to hand hygiene for a full month after a gastroenteritis. that means thorough hand washing on every bathroom trip and keeping alcohol-based hand sanitizer around for easy use by all household members.
how long is stomach flu contagious?