From the Guidelines
Norwalk virus, also known as norovirus, is a highly contagious virus that causes gastroenteritis, an inflammation of the stomach and intestines, as classified in the genus Norovirus of the family Caliciviridae 1. It spreads easily through contaminated food or water, by touching contaminated surfaces, or through direct contact with an infected person. Symptoms typically include sudden onset of nausea, vomiting, watery diarrhea, and abdominal cramps, often accompanied by low-grade fever, headache, and body aches. These symptoms usually appear 12-48 hours after exposure and last 1-3 days. There is no specific medication to treat norovirus infection as antibiotics are ineffective against viruses. Treatment focuses on preventing dehydration by drinking plenty of fluids to replace those lost through vomiting and diarrhea. Over-the-counter medications like acetaminophen can help relieve fever and body aches. Prevention involves thorough handwashing with soap and water, especially after using the bathroom and before handling food, proper disinfection of contaminated surfaces with bleach-based cleaners, and avoiding food preparation for others while sick and for at least 48 hours after symptoms resolve, as recommended by the updated norovirus outbreak management and disease prevention guidelines 1. The virus is particularly problematic in closed environments like cruise ships, nursing homes, and schools due to its high contagiousness and environmental stability, causing at least 50% of all gastroenteritis outbreaks worldwide, and approximately 21 million illnesses attributable to norovirus are estimated to occur annually in the United States 1. Some key features of norovirus infection include:
- Acute onset, nonbloody diarrhea, vomiting, nausea, and abdominal cramps 1
- Incubation period of 12–48 hours 1
- Low-grade fever and body aches may also be associated with infection 1
- Asymptomatic persons can shed virus, albeit at lower titers than symptomatic persons, and the role of asymptomatic infection in transmission and outbreaks of norovirus remains unclear 1. Overall, norovirus is a significant public health concern, and prevention and control measures are crucial to reducing the spread of the virus, especially in high-risk settings.