II. Epidemiology
- Epidemic outbreaks of Acute Diarrheal illness
- Most common cause of Viral Gastroenteritis in the world
- Causes 90% of non-Bacterial Gastroenteritis (and 18% of all Gastroenteritis)
- Norwalk Virus
- Named for a Gastroenteritis outbreak at an elementary school in Norwalk Ohio (1968)
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Caliciviridae (Calicivirus)
- Human Caliciviruses primarily cause acute Viral Gastroenteritis (fecal-oral transmission)
- Caliciviridae are a family of non-enveloped (naked) RNA Viruses with an icosahedral capsid
- Caliciviridae are Message Sense RNA Viruses (Positive Stranded, +ssRNA)
- Message sense RNA (+ssRNA) are identical to Messenger RNA (mRNA)
- Like mRNA, +ssRNA may be immediately translated by host ribosomes into Protein
III. Pathophysiology
- Taxonomy
- Family: Caliciviridae
- Genus: Norovirus
- Species: Norwalk Virus
- Transmission
- Fecal-oral route (Foodborne Illness or Waterborne Illness)
- Fomites and surfaces
- Precautions
- Highly contagious
- Bleach is effective at killing virus on surfaces (but many other disinfectants are not)
IV. Causes: Sources
- Contaminated drinking water
- Contaminated raw produce or uncooked food
- Shellfish from contaminated water
- Food contaminated by infected food handler
V. Symptoms
- Onset: 12 to 48 hours after exposure
- Duration: 12 to 60 hours
- Illness may be prolonged for months in Immunocompromised patients
- Systemic symptoms
- Low grade fever (variably present)
- Lethargy
- Weakness
- Myalgias
- Malaise
- Headache
- Gastrointestinal symptoms
- Nausea
- Projectile Vomiting (esp. children)
- Watery Diarrhea
- Abdominal Pain
VI. Prevention
- Antibody to Norwalk is not protective
VII. Resources
- CDC Norovirus
- Wikipedia Norovirus