Norovirus, often called the “stomach flu” or “stomach bug,” is a highly contagious virus that causes inflammation of the stomach or intestines, known as acute gastroenteritis. This common illness leads to sudden vomiting and diarrhea, affecting people of all ages. Its widespread nature and ease of transmission make understanding norovirus important for public health.
How Norovirus Spreads
Norovirus spreads very easily, primarily through the fecal-oral route. This means the virus is found in the stool and vomit of infected individuals and can be transmitted when microscopic particles are ingested. Direct contact with someone who has norovirus, such as caring for them or sharing food, can lead to infection.
The virus also spreads by consuming contaminated food or water. This can occur if food is prepared by an infected person who has not thoroughly washed their hands, or if shellfish like oysters and clams are eaten raw or undercooked. Touching contaminated surfaces or objects and then touching your mouth before washing your hands is another common way to get sick. As few as 100 virus particles are thought to be enough to cause infection.
Symptoms and What to Expect
Norovirus infection symptoms begin suddenly, 12 to 48 hours after exposure. These include nausea, vomiting, diarrhea, and stomach cramps. Some individuals may also experience a low-grade fever, headache, and body aches.
Most people feel better within one to three days. However, cases in young children, older adults, and hospitalized patients can last longer, up to four to six days. Dehydration is a primary concern due to frequent vomiting and diarrhea. Signs of dehydration include decreased urination, a dry mouth and throat, and dizziness when standing.
Managing Norovirus at Home
Managing norovirus at home focuses on preventing dehydration due to fluid loss. Drink plenty of liquids like water, oral rehydration solutions, or clear broths, taking small sips if feeling sick. Avoid sugary drinks, caffeine, and alcohol, as they can worsen dehydration.
When able to eat, consume bland foods such as bananas, rice, applesauce, and toast (BRAT diet) is recommended. These foods are easier on the stomach during recovery. Avoid fatty, spicy, or dairy foods until symptoms subside. Getting plenty of rest also supports recovery. Seek medical attention if signs of severe dehydration develop, such as infrequent urination, extreme dizziness, or if symptoms worsen.
Preventing Norovirus Infection
Preventing norovirus infection begins with thorough handwashing using soap and water, especially after using the restroom, changing diapers, and before preparing or eating food. Alcohol-based hand sanitizers are less effective against norovirus than soap and water. Wash hands for at least 20 seconds to reduce viral contamination.
Food safety practices are also important. Properly cook shellfish, particularly oysters and clams, and thoroughly wash raw fruits and vegetables with clean running water before consumption. Immediately clean and disinfect contaminated surfaces after illness is important, using a bleach-based cleaner or a solution of 12 ounces of bleach per gallon of water.
Wash contaminated clothing and linens separately in hot water, preferably at 60°C (140°F). Individuals with norovirus should stay home from work or school and avoid preparing food for others for at least 48 hours after symptoms have completely resolved, as the virus can still be shed.