UW News

February 10, 2005

That ‘stomach flu’ might be a norovirus

The party was delightful, the wine was fine, the music was great and the potluck buffet was so tasty that you got back in line twice. Unfortunately, you and a lot of your friends awoke with an ailment that’s a great deal more uncomfortable than a hangover.

You suffered from nausea, vomiting and diarrhea for from one to several days and told people at work that you’d had the stomach flu.

It’s more likely that you were suffering from a norovirus, once referred to as Norwalk virus. Dr. Jeff Duchin, the chief of communicable disease control at Public Health Seattle & King County, says actual flu virus rarely strikes the stomach in adults, while noroviruses are the most common form of food-borne illness in the United States, resulting in over 20 million cases a year.

Norovirus is the term used for a group of closely related, highly infectious viruses that are transmitted through the fecal-oral route and that cause acute gastroenteritis. Incubation is usually 24 to 48 hours, although onset can be as fast as 12 hours. It was dubbed Norwalk virus after a 1968 outbreak in Norwalk, Ohio, led to the virus’ identification.

“It’s sometimes called winter vomiting disease, although it is present year round,” Duchin says. “Summer camps are a big norovirus setting, although it can crop up at any time you have large numbers of people sharing common meals. We’ve had outbreaks on cruise ships as well, but the virus is more prevalent in the wintertime.”

Most people feel miserable for a couple of days, and then recover, but dehydration can be a threat for some patients.

“That can be serious for elderly people and those who have cardiovascular problems, as well as young infants who can’t take in fluids very well,” Duchin says. “Most people can take enough by mouth that they don’t become dehydrated.”

Once the virus finds its way into the house, you can take steps to prevent the spread of the disease from person to person.

“It is highly contagious, spreading when a sick person or someone who was recently ill doesn’t practice good, frequent hand-washing. It also spreads when people who are ill or recently recovered prepare food for others and don’t use good food preparation practices or wash their hands frequently,” Duchin says. “Norovirus can also spread to people and objects in the vicinity of vomiting people.”

To control norovirus outbreaks, Duchin emphasizes simple steps:

  • Frequent hand washing, before and after preparing food and after using the toilet.
  • Thorough, prompt clean-up of any vomit on floors or other surfaces, using household disinfectants.
  • Good hygiene and safe food preparation techniques in preparing and serving meals and snacks.

The discouraging part of a bout of norovirus is that people don’t develop a long-lasting immunity.

“You don’t develop protection just because you’ve had it once and people shouldn’t feel they can relax good hygiene measures that are necessary to prevent infection from noroviruses just because they’ve had an episode,” Duchin says. “You need to stay on your guard to prevent food-borne illness and person-to-person transmission of the infection.”