Search Results (3)

The family Caliciviridae encompasses a diverse group of non-enveloped, positive-sense RNA viruses that are significant pathogens in veterinary medicine. This narrative review summarizes the current state of knowledge regarding the clinical, molecular, and epidemiological features of the three calicivirus genera identified in bovine hosts: Norovirus, Nebovirus, and Vesivirus. Bovine noroviruses and neboviruses are neglected enteric pathogens, frequently detected in association with neonatal calf diarrhea and often present in co-infections with other enteric agents. Clinical presentations for these enteric viruses range from severe, watery diarrhea to asymptomatic shedding, with distinct pathogenic profiles observed between norovirus genotypes GIII.1 and GIII.2. In contrast, the genus Vesivirus exhibits a broad host range, and bovine vesivirus strains are phylogenetically linked to vesiviruses identified in pigs and marine animals. Bovine vesivirus infections are associated with a broader spectrum of clinical manifestations, including respiratory disease, vesicular lesions, and abortion. Serological and virological surveys indicate that exposure to these viruses is ubiquitous in cattle populations globally. While direct evidence of human infection by bovine noroviruses and neboviruses remains limited, vesiviruses possess a confirmed capacity for cross-species transmission to humans. Significant knowledge gaps remain, particularly regarding in vitro culture systems, necessitating further research to facilitate vaccine development and clarify transmission dynamics. Full article

Neboviruses (NeVs) from the Caliciviridae family have been linked to enteric diseases in bovines and have been detected worldwide. As viruses rely entirely on the cellular machinery of the host for replication, their ability to thrive in a specific host is greatly impacted by the specific codon usage preferences. Here, we systematically analyzed the codon usage bias in NeVs to explore the genetic and evolutionary patterns. Relative Synonymous Codon Usage and Effective Number of Codon analyses indicated a marginally lower codon usage bias in NeVs, predominantly influenced by the nucleotide compositional constraints. Nonetheless, NeVs showed a higher codon usage bias for codons containing G/C at the third codon position. The neutrality plot analysis revealed natural selection as the primary factor that shaped the codon usage bias in both the VP1 (82%) and VP2 (57%) genes of NeVs. Furthermore, the NeVs showed a highly comparable codon usage pattern to bovines, as reflected through Codon Adaptation Index and Relative Codon Deoptimization Index analyses. Notably, yak NeVs showed considerably different nucleotide compositional constraints and mutational pressure compared to bovine NeVs, which appear to be predominantly host-driven. This study sheds light on the genetic mechanism driving NeVs’ adaptability, evolution, and fitness to their host species. Full article

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. Full article