Knoxville (WVLT) - Many people mistake viruses for the flu and similarly many dismiss Norovirus as some sort of "stomach bug."
The number of cases of Norovirus seems to be increasing across the country, and many people don't even know what it is or how it's spread.
You've probably seen and heard the media reports of hundreds of cruise ship passengers coming down with a gastrointestinal illness, all at once.
But whether you know it or not, that probably wasn't your first encounter with Norovirus.
"Most people don't seek medical attention, so most of us have probably had a case of Norovirus, but haven't sought medical attention for it, because we get better before we even get into the doctor," says Knox County Public Health Officer Dr. Martha Buchanan.
In most people, Norovirus lasts 24 to 48 hours.
Symptoms include nausea, vomiting, diarrhea, stomach cramps and low-grade fever.
It's most commonly spread by eating contaminated food.
"What happens on the cruise ship or in the restaurant is you get a sick food worker who passes it to a whole bunch of people all at once, and so that's when we have an outbreak," explains Dr. Buchanan.
In fact, 28 cruise ship outbreaks were reported to the cdc just last year.
And nursing home trade groups say more facilities are reporting outbreaks than in recent years.
The spike in cases is prompting the federal government to better track movement of Norovirus across the country.
But it's still not a what's called a reportable illness, like the flu, that's tracked by the CDC.
"It's not reportable at this time, and they may be moving to making it reportable, so that we do have to keep data on it," says Dr. Buchanan.
Doctor Martha Buchanan says the Health Department reports Norovirus outbreaks to the state, usually an average of one or two a year.
And as of last week, the CDC is asking state health officials to provide information on outbreaks for a report to be issued in the next few weeks.
Norovirus typically strikes nursing homes, day care centers, hospitals and other group settings in the winter, and cruise ships all year round.
Though, this current wave of outbreaks could be linked to a new strain of the virus discovered last spring.
Hand-washing and good sanitation are the best ways to prevent the virus from spreading.