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, in an effort to control its rabbit population, has intentionally spread calicivirus.
Transmission of caliciviruses is generally by the fecal-oral route, but they can also be transmitted via the respiratory
Calicivirus infections commonly cause acute gastroenteritis and 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.