What are the treatment and management options for Norwalk virus infection?

Treatment and Management of Norwalk Virus Infection

The cornerstone of Norwalk virus (norovirus) management is oral rehydration therapy, with supportive care focused on preventing dehydration and electrolyte imbalances, as this is a self-limited illness typically resolving within 24-72 hours. 1

Clinical Management Algorithm

1. Hydration Management

• First-line treatment: Oral rehydration therapy (ORT) using oral rehydration solution (ORS)
  • For children: WHO or commercially available ORS formulations
  • For adults: Clear fluids, sports drinks, or diluted fruit juices
• Severe dehydration: Intravenous fluid replacement only when oral intake is inadequate or dehydration is severe 2

2. Symptomatic Treatment

• Antiemetics: Consider ondansetron for severe vomiting preventing adequate oral rehydration, particularly in children >4 years 1
• Bismuth subsalicylate: May reduce duration of Norwalk infection from 27 to 20 hours 2, 1
• Antimotility drugs:
  • Contraindicated in children <18 years
  • May be used cautiously in adults without fever or bloody diarrhea 1

3. Nutritional Support

• Continue normal feeding during illness when possible
• Resume age-appropriate usual diet during or immediately after rehydration
• Easily digestible foods recommended (bananas, rice, applesauce, toast) 1
• Breast milk has protective effects against viral enteric infections; infants can usually be "fed through" an episode 2, 1

Special Population Considerations

Children

• Higher risk of dehydration; monitor closely
• May experience more severe symptoms and slightly longer duration 1
• Mild lactose intolerance may develop 10-14 days after rotavirus infection 2

Elderly

• At higher risk for severe dehydration and electrolyte imbalances
• May experience prolonged constitutional symptoms for several weeks 1
• Those receiving diuretic medications require particular attention to hydration status 2

Immunocompromised Individuals

• May experience prolonged viral shedding and more severe disease 1
• Require closer monitoring for complications

Infection Control Measures

Personal Hygiene

• Vigorous handwashing with soap and water for at least 20 seconds
  • Alcohol-based hand sanitizers (≥70% ethanol) can be used as an adjunct but not a substitute for handwashing 2
• Exclude ill staff in food service, childcare, and healthcare settings until 48-72 hours after symptom resolution 2

Environmental Control

• Clean and disinfect contaminated surfaces with:
  • Chlorine bleach solution (1,000-5,000 ppm; 1:50-1:10 dilution of household bleach) 2
  • EPA-approved disinfectants with label claims for norovirus 2
• Handle soiled linens with minimal agitation; launder with detergent at maximum cycle length 2

Outbreak Management

• Isolate ill persons in institutional settings for 24-48 hours after symptom resolution 2
• Food handlers should not prepare food for at least 2 days after resolution of illness 1
• Collect stool specimens from at least 5 persons during acute phase (≤72 hours from onset) for diagnosis 2

Pitfalls and Caveats

1. Antimicrobial resistance: Antibiotics are ineffective and not indicated as Norwalk virus is a viral infection 2

2. Rehydration challenges: Vomiting may impede oral rehydration; small, frequent sips may be better tolerated than larger volumes 1

3. Disinfection limitations: Norwalk virus is highly resistant to chlorine (requires 10 mg/L for inactivation) compared to other enteric viruses 2

4. Transmission risks: Norwalk virus can remain infective when frozen for years or heated to 60°C for 30 minutes; cooking temperatures at boiling or above are needed for inactivation 2

5. Secondary spread: High secondary attack rates (50-70%) necessitate strict infection control measures to prevent institutional outbreaks 1, 3

By following this management approach, healthcare providers can effectively manage Norwalk virus infections while minimizing complications and preventing further transmission.