How Norovirus Spreads and What to Do When It Arrives in Your Home

The “stomach bug” or norovirus, can be a seasonal “downer” for the whole family. This so-called “perfect pathogen” is heartier than you might imagine. It spreads easily, remains viable on environmental surfaces for days (if it’s not hit with an effective disinfectant), and mutates over time, raising the possibility that your first harrowing experience with norovirus will not be your last.

Norovirus: Image courtesy of the Centers for Disease Control and Prevention

The Centers for Disease Control and Prevention (CDC) reports norovirus outbreaks are most common each year between November and April. In a typical year, there are between 19 and 21 million cases of norovirus in the US, tens of thousands of hospitalizations, and hundreds of deaths (mostly in young children and the elderly). Illness cases can rise significantly when a new strain of the virus circulates. Unlike seasonal flu, there is no vaccine for norovirus, but ongoing research could lead to a vaccine strategy.

Norovirus spreads by: person-to-person contact (including hand to hand to mouth contact); consuming fecally contaminated food or water; or touching contaminated surfaces and then putting unwashed hands in the mouth or the eyes. Norovirus causes inflammation of the stomach or intestines resulting in diarrhea, vomiting, nausea and stomach pain. Other symptoms may include fever, headache, and body aches, according to CDC. Symptoms generally develop in people within 12 to 48 hours of being exposed to norovirus. As the body loses water and salts from vomiting and diarrhea, the risk of dehydration rises, especially in young children, older adults, and people with other illnesses. WebMD advises dehydration can be prevented by taking in adequate amounts of fluids, especially water and juices. Mercifully, norovirus symptoms usually subside within one to three days.

Don’t Underestimate Norovirus’ Ability to Spread

The vomiting and diarrhea that norovirus causes in a human host is the virus’ way of casting itself into the environment in an endless “search” for new human hosts. And how effective that is for norovirus! A customer who vomited at a Tennessee restaurant on Thanksgiving last year triggered a norovirus outbreak in which 34 other diners were sickened. According to a CDC report on the outbreak, a restaurant employee used a spray disinfectant to clean the affected area, washed his or her hands, and then proceeded to serve platters of food.

Investigators found norovirus in some patient stool samples and from an environmental sample collected from a table leg. They determined that customers who were seated around the time of the vomiting incident were significantly more likely to become ill than customers served at other times on that day. They concluded norovirus particles had spread by multiple routes through the restaurant, including: tiny droplets in the air; person-to-person contact; patron contact with contaminated environmental surfaces; and food contamination that might have been facilitated by the employee’s inadequate hand-washing.

CDC Video: How to Squash Norovirus

The CDC video above provides clear, step-by-step directions on how to clean up and sanitize your surroundings following a “norovirus incident,” such as vomiting. Importantly, the viewer is instructed to don disposable gloves and a face mask, if possible, before cleaning up the virus-rich bodily fluids. Personal protection is important because, as CDC tells us, it only takes a few virus particles to make a person sick, yet those infected with the virus shed billions of norovirus particles. Our recommendation? Save the link to “Squash Norovirus” in the event norovirus invades your home.

CDC promotes many helpful resources on its norovirus multimedia page, including these posters, which the Water Quality & Health Council helped develop. These and other surface disinfection posters are downloadable at


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