Caliciviridae Other Than Noroviruses

Abstract

Besides noroviruses, the Caliciviridae family comprises four other accepted genera: Sapovirus, Lagovirus, Vesivirus, and Nebovirus. There are six new genera proposed: Recovirus, Valovirus, Bavovirus, Nacovirus, Minovirus, and Salovirus. All Caliciviridae have closely related genome structures, but are genetically and antigenically highly diverse and infect a wide range of mammalian host species including humans. Recombination in nature is not infrequent for most of the Caliciviridae, contributing to their diversity. Sapovirus infections cause diarrhoea in pigs, humans and other mammalian hosts. Lagovirus infections cause systemic haemorrhagic disease in rabbits and hares, and vesivirus infections lead to lung disease in cats, vesicular disease in swine, and exanthema and diseases of the reproductive system in large sea mammals. Neboviruses are an enteric pathogen of cattle, differing from bovine norovirus. At present, only a few selected caliciviruses can be propagated in cell culture (permanent cell lines or enteroids), and for most of the cultivatable caliciviruses helper virus-free, plasmid only-based reverse genetics systems have been established. The replication cycles of the caliciviruses are similar as far as they have been explored: viruses interact with a multitude of cell surface attachment factors (glycans) and co-receptors (proteins) for adsorption and penetration, use cellular membranes for the formation of replication complexes and have developed mechanisms to circumvent innate immune responses. Vaccines have been developed against lagoviruses and vesiviruses, and are under development against human noroviruses.

Genomic Analyses of Human Sapoviruses Detected over a 40-Year Period Reveal Disparate Patterns of Evolution among Genotypes and Genome Regions

“…Recombination between the RdRp-and VP1-encoding genes has been extensively shown for noroviruses, and proposed to play a major role in the emergence of novel strains [14,66,67]. In sapoviruses, the RdRp and VP1 proteins are encoded in the same ORF1, while in noroviruses, those proteins are encoded by two different ORFs [15]; ORF1 and ORF2, respectively. The high frequency of RdRp-VP1 recombinant norovirus strains has been explained by the fact that the ORF1/2 junction region is highly conserved across norovirus strains, which facilitates template switching between the genomic and/or sub-genomic RNA that encodes VP1 and VP2 [67].…”

“…Indeed, recombination has been shown to be an important mechanism of diversification for norovirus and other caliciviruses [1,14,15]. Some of the recombination events reported for sapoviruses did not clearly describe both parental strains [5][6][7]10,13], thus the "recombination signal" might be confounded by the possibility of different evolutionary diversification patterns among sapovirus genomic regions [16].…”

Nitazoxanide protects cats from feline calicivirus infection and acts synergistically with mizoribine in vitro

“…Feline calicivirus (FCV), the major representative of the family Caliciviridae, primarily causes upper respiratory tract disease in cats. Highly virulent strains of FCV (VS-FCV) can cause systemic diseases, including subcutaneous edema, necrosis in multiple organs (liver, spleen, pancreas) and interstitial pneumonia (Desselberger, 2019). FCV vaccines have been commercially available for 30 years but FCV remains highly prevalent among cats, and none of the vaccines currently on sale can protect cats from all strains of FCV (Sato et al, 2017).…”

A common problem in the purification of calicivirus raised by molecular sieving: balance between purification and loss of viral particles

“…Caliciviridae are nonenveloped, positive-stranded RNA viruses including Norovirus, Sapovirus, Lagovirus, Vesivirus and so on [1]. Norovirus and Sapovirus could lead to gastrointestinal disease in humans and not easy to study in laboratory [2]. Feline Calicivirus (FCV), due to the advantages of the safety as well as the ease to culture and replicate compared with other kinds of viruses in Caliciviridae, shows important research value and becomes a very good model for relative studies.…”