Norovirus
Written by Pal Randhawa, Dalhousie undergraduate student, April 2009
- epidemiology
- classification and characteristics
- transmission and infection
- pathogenicity and virulence
- clinical manifestations
- diagnosis
- treatment
Epidemiology
Classification and Characteristics
smaller than rotaviruses
Transmission and Infection
Transmission associated with
- contaminated food
- person to person contact
- oysters
- contaminated water
However, many times the mode of transmission is not clear.
Pathogenicity and Virulence
Norovirus damages intestinal microvilli, resulting in malabsorption of fat.
Virulence occurs due to the following features:
- low infectious dose
- prolonged asymptomatic shedding
- environmental stability
- strain diversity
- incomplete immunity
Clinical Manifesations
Symptoms vary patient to paitient, but are typified by explosive projectile vomiting, diarrhea or both.
Also common are:
- myalgias
- malaise
- headache
- low grade flu like symptoms
Clinical criteria include:
- short incubation period
- short symptomatic illness
- high frew of vomiting
- absence of bacterial pathogens
Diagnosis
Norovirus is non–culturable, but can be detected with PCR.
Treatment
Norovirus is self-limiting, and treatment is supportive in nature.