Norovirus Symptoms, Duration, Transmission, and Prevention

Norovirus is the leading cause of acute gastroenteritis worldwide. Key facts:

Symptoms (12–48h post‑exposure)

• Sudden nausea, projectile vomiting.
• Watery, non‑bloody diarrhea.
• Abdominal cramps.
• Low‑grade fever, headache, myalgias, fatigue.

Course

• Typically 24–72 hours.
• Viral shedding persists 2+ weeks after recovery.
• Dehydration risk highest in young children, elderly, immunocompromised.

Transmission

• Fecal‑oral: contaminated food/water, fomites, aerosolized vomit.
• Extremely contagious: <100 virions can infect.
• Outbreaks: cruise ships, nursing homes, schools, restaurants.

Prevention

• Handwashing with soap/water (≥20 sec) – alcohol gels less effective against norovirus.
• Bleach‑based disinfection (1000–5000 ppm) for surfaces.
• Exclude ill food handlers ≥48h after symptom resolution.
• Cook shellfish thoroughly; wash produce.

Management

• Oral rehydration (ORS) – primary treatment.
• Antiemetics (ondansetron) if needed.
• No antibiotics (viral).
• Isolate until 48h symptom‑free.

No vaccine yet; candidate vaccines in trials. Immunity is short‑lived and strain‑specific.