Norovirus, rotavirus, or stomach flu - what's the difference?

Sherry Kuyt | Advance Newspapers By Sherry Kuyt | Advance Newspapers
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on January 26, 2012 at 3:40 PM, updated April 05, 2013 at 9:28 PM

CDC Norovirus.jpg Norovirus, which resembles tiny clusters of grapes, is often the real culprit behind so-called 'stomach flu.'
If you're suffering from vomiting or diarrhea, you may not know - or care - exactly which bug caused your complaint.

In fact, many people refer to gastrointestinal illness simply as “stomach flu.”

But that’s a misnomer, according to Cindy Stiles, a registered nurse with the Allegan County, Michigan Health Department.

She said these cases probably aren’t real “flu” or influenza, which is a respiratory illness. Instead, rotavirus and norovirus are often the culprits, although they are rarely identified.

“It is more common than people think, and is responsible for much of 'stomach flu' or the '24-hour bug'” she said.

“I haven't heard of any cases of noro in Allegan County, but there have been cases and outbreaks in Region 5 and all over Michigan for that matter."

Brian Hartl, an epidemiologist for the Kent County, Michigan Health Department, said norovirus is a likely suspect when gastrointestinal illness affects long-term care facilities.

If these viruses are so common, why are the cases rarely confirmed? Perhaps it's because most people just suffer at home, and don't go to the doctor or emergency room unless their symptoms are severe.

If a medical staff member wants to turn in a sample for testing to the Michigan Health Department in Lansing, he or she must arrange for the test ahead of time, and there is a cost of at least $200.

By the time the results are back, the patient is often feeling better. So testing is often reserved for cases which occur in schools, nursing homes, or other places where the higher number of people in the same facility creates a greater risk.

"Norovirus is very contagious, and can be easily spread from person to person, especially in group settings," Stiles said.

Norovirus gets its name from Norwalk, Ohio, where an outbreak occurred in 1968. The round-shaped virus affects all ages, and is a common cause of "food poisoning."

Another germ - rotavirus, named for its wheel-like shape - is the most common cause of severe diarrhea among children, according to the Centers for Disease Control and Prevention (

Children often contract the illness when they put their fingers or other contaminated objects into their mouths. Adults infected with rotavirus may not have symptoms, but can still spread the illness to others.

Both norovirus and rotavirus thrive in fecal matter, and a common method of transmission is poor bathroom hygiene - neglecting to wash the hands after using the toilet or changing a diaper.

They are also transmitted when an infected person's unwashed hands touch food or other objects, including dishes, doorknobs, faucets, and other surfaces.

Vaccines are available for rotavirus, but are not yet available for norovirus. Rotavirus infections tend to occur during the cooler months (October to April), while norovirus strikes all year long.

Whether the offender is norovirus, rotavirus, or some other germ, the treatment for gastrointestinal illness is basically the same: get lots of rest, drink clear liquids, and nibble on crackers until you feel better.

Those whose symptoms are severe, or who belong to a special risk group - including infants and the elderly - should check with a physician.

The "flu shot" does not prevent this type of illness, but there are other ways to keep it from spreading, according to Stiles.

"People can reduce their chance of getting infected by frequent hand washing, using soap and warm, running water for a minimum of 20 seconds," she said. "Alcohol-based hand sanitizers do not work against norovirus."

People should avoid sharing food or drinks, and should use bleach or other disinfectants to keep surfaces clean. It is also important to thoroughly wash clothes and towels used by a sick person.

"Since the virus is passed in vomit and stool, children should not go to daycare or school while they have diarrhea or vomiting," said Stiles.

"Persons who work in nursing homes, take care of patients, or handle food should stay out of work until at least two to three days after symptoms end."

To see more stories by Sherry Kuyt, visit or You can also follow her on Twitter, @Skuyt.