Norovirus infection
Norovirus is the most common cause of acute gastroenteritis in the United States, producing watery, noninflammatory diarrhea with prominent vomiting after a short incubation period, spreading efficiently via the fecal-oral route with an infectious dose under 100 viral particles and viral shedding for up to two weeks after symptoms resolve; diagnosis is clinical or by nucleic acid amplification testing, and treatment is entirely supportive oral or IV rehydration since no antiviral or antimicrobial therapy exists.
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What this article covers
- Overview
The leading cause of acute viral gastroenteritis, across all ages: norovirus causes roughly 50% of all acute diarrhea in the United States and is the most common cause of gastroenteritis overall…
- Epidemiology
Norovirus is the most common cause of gastroenteritis in the United States, affecting all ages, in contrast to rotavirus, which is concentrated in young children.
- Risk factors
Close-quarters institutional settings (cruise ships, schools, long-term care facilities, healthcare facilities), where person-to-person and fomite transmission is efficient.
- Pathophysiology
Fecal-oral acquisition of a very low viral inoculum (under 100 particles) initiates infection, reflecting norovirus's exceptionally high infectivity relative to bacterial enteric pathogens.
- Clinical features
Watery, noninflammatory diarrhea, the hallmark presentation, without blood or the systemic toxicity typically seen in invasive bacterial diarrheal illness.
- Differential diagnosis
Rotavirus infection: another viral cause of acute watery diarrhea and vomiting, but concentrated in unvaccinated children under 2 years and associated with daycare exposure, rather than affecting all…
- Diagnosis
Norovirus gastroenteritis is a clinical diagnosis in the large majority of cases, based on the characteristic short-incubation, watery, noninflammatory diarrhea with prominent vomiting and fever…
- Management
First, assess hydration status, then begin oral rehydration therapy in any patient who can tolerate oral intake: an oral rehydration solution dosed at approximately 50-100 mL/kg over 4 hours to…
- Complications
Dehydration, the principal complication, ranging from mild to severe and occasionally requiring hospitalization for intravenous fluid support, particularly in young children, older adults, and patients with reduced oral intake.
- Prognosis
Excellent in the large majority of patients: norovirus gastroenteritis is self-limited, with symptom resolution typically within a few days and supportive care sufficient for recovery.
- Prevention
Rigorous hand hygiene with soap and water (norovirus is relatively resistant to alcohol-based hand sanitizer) after using the bathroom, before food preparation, and after contact with a symptomatic…
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Related articles
- Rotavirus infection
Rotavirus is a segmented double-stranded RNA reovirus and the classic cause of acute watery diarrhea and vomiting in young children, with fecal-oral transmission and a wintertime, daycare-associated pattern. Diagnosis is clinical; management is rehydration, and prevention rests on the live oral rotavirus vaccine.
- Campylobacter infection
Campylobacter is a comma-shaped, gram-negative bacillus and a leading cause of bacterial bloody diarrhea from undercooked poultry, unpasteurized milk, or infected animal contact, usually self-limited but treated with azithromycin for severe or high-risk disease, and a recognized trigger of Guillain-Barre syndrome and reactive arthritis.
- Isolation precautions
Isolation precautions pair standard precautions, used for every patient, with transmission-based precautions selected by a suspected or confirmed organism's dominant route: contact (gloves and gown), droplet (mask within 3 to 6 feet), or airborne (a negative-pressure room and a fit-tested N95 respirator). Hand hygiene and matching the barrier to the route are the core interventions.
- Escherichia coli infection
Escherichia coli is a gram-negative bacillus that causes most urinary tract infections and catheter-associated bloodstream infections, plus distinct diarrheagenic syndromes including travelers' diarrhea (ETEC) and hemorrhagic colitis with hemolytic uremic syndrome (EHEC/STEC). Diagnosis rests on culture with syndrome-specific colony-count thresholds, and management ranges from short-course oral antibiotics for cystitis to strictly supportive, antibiotic-avoiding care for EHEC.