From the Guidelines
Norovirus is a highly contagious virus that causes gastroenteritis, responsible for at least 50% of all gastroenteritis outbreaks worldwide, and a major cause of foodborne illness, as reported in the updated guidelines by the MMWR Recommendations and Reports in 2011 1. Norovirus, also known as Norwalk-like virus, is a common cause of epidemic gastroenteritis, estimated to cause approximately 21 million illnesses annually in the United States alone 1. The virus spreads easily through:
- Contaminated food
- Water
- Surfaces
- Direct contact with infected individuals Symptoms of norovirus infection typically include:
- Sudden onset of nausea
- Vomiting
- Watery diarrhea
- Stomach cramps
- Low-grade fever
- Headache
- Body aches These symptoms usually appear 12-48 hours after exposure and last 1-3 days. According to the guidelines, treatment focuses on preventing dehydration through oral rehydration with water, sports drinks, or oral rehydration solutions like Pedialyte 1. No specific antiviral medication exists for norovirus, and antibiotics are ineffective since it's viral. Prevention is crucial and includes:
- Thorough handwashing with soap and water for at least 20 seconds, especially after using the bathroom and before handling food
- Avoiding preparing food for others for at least 48 hours after symptoms resolve, as the virus can continue shedding 1. Norovirus is particularly problematic in closed settings like cruise ships, schools, and healthcare facilities because it requires only a small amount of virus particles to cause infection and can survive on surfaces for days or weeks.
From the Research
Definition and Characteristics of Norovirus
- Norovirus is a leading cause of childhood vomiting and diarrhea in the United States and globally 2
- It is an enteric non-enveloped virus that is the leading cause of gastroenteritis across all age groups 3
- Norovirus is responsible for around 200,000 deaths annually and outbreaks are common in small communities such as educational and care facilities 3
- The virus is genetically diverse with multiple genogroups and genotypes cocirculating globally and causing disease in humans 4
Transmission and Outbreaks
- Norovirus is primarily transmitted via the fecal-oral route and only a very small number of virions are required for infection 4
- Outbreaks of norovirus are extremely difficult to control when they occur, especially in settings like long-term care facilities, daycares, and hospitals 3, 4
- The virus can be spread directly from individual to individual as well as indirectly via contaminated food and water 5
Symptoms and Treatment
- Norovirus infection is characterized by diarrhea, vomiting, fever, headache, and stomach pain 5
- Gastroenteritis develops 12 to 48 hours after exposure and recovery typically occurs within 1 to 3 days 5
- There is no specific treatment of norovirus gastroenteritis, and available treatments are limited to rehydration therapies and supportive care 2, 4
Prevention and Control
- Prevention of norovirus infection depends mainly on strict personal and community hygiene measures, such as hand washing and cleaning or disinfection of contaminated surfaces 6, 5
- Vaccines to prevent norovirus illness are currently under development, with several candidates in clinical trials 2, 3, 4