Norovirus (Caliciviridae)
Caliciviridae: Norovirus
Key Features
Naked RNA viruses with icosahedral capsids.
Caliciviridae comprise single-stranded, positive sense RNA genomes.
Norwalk virus is the prototypical species. Referred to as the "winter vomiting bug."
Round ichosahedral shape with characteristic "spikes" on its surface.
Norovirus is a leading cause of epidemic and sporadic gastroenteritis
Vomiting, watery diarrhea, and stomach pain.
Norovirus infection is often thought of as "stomach flu," and is responsible for approximately 20 million cases of gastroenteritis in the United States per year.
Symptoms are typically self-limiting, and last approximately three days.
However, illness may be more severe in the very young or very old.
No specific treatment, but rehydration therapy (administration of water and electrolytes) is recommended.
Transmitted via the fecal-oral route; often in contaminated water or foods.
Low infectious dose (relatively few virions can cause infection).
Prolonged viral shedding promotes transmission from host to host.
Genetically diverse, so re-infection by different strains is possible.
No vaccine.
Prevention = good hygiene, including thorough hand washing.
Sapovirus is another genus of Caliciviridae that infects humans and causes gastroenteritis.