Caliciviridae



Vesivirus Lagovirus Norovirus Sapovirus

The Caliciviridae family are members of Class IV of the Baltimore scheme. They are positive-sense, single stranded RNA which is non-segmented. The caliciviruses have been found in a number of organisms such as humans, cattle, pigs, chickens, reptiles, dolphins and amphibians. The caliciviruses have a simple construction and are not enveloped. The capsid appears hexagonal/spherical and has icosahedral symmetry with a diameter of 35-39nm.

Caliciviruses are not very well studied because they do not grow in culture and there is no suitable animal model. Only recently have advances in molecular biology enabled the viral genome to be determined.

The name calicivirus is derived from the Latin word calyx meaning cup or goblet. This name is appropriate as many strains have visible cup-shaped depressions.

The Caliciviridae family include the following genera:
 * Genus Vesivirus; type species: Swine vesicular exanthema virus
 * Genus Lagovirus; type species: Rabbit hemorrhagic disease virus
 * Genus Norovirus; type species: Norwalk virus
 * Genus Sapovirus; type species: Sapporo virus

Australia and New Zealand, in an effort to control its rabbit population, has intentionally spread calicivirus.

Transmission
Transmission of caliciviruses is generally by the fecal-oral route, but they can also be transmitted via the respiratory route.

Human disease
Calicivirus infections commonly cause acute gastroenteritis,which is the inflammation of the stomach and intestines. Symptoms can include vomiting and diarrhoea. These symptoms emerge after an incubation time of 2 days and the symptoms only generally last for 3 days. Most calicivirus infections do not call for medical attention, but those who are immunocompromised may need to be hospitalised for rehydration therapy.