Kobuvirus

Kobuvirus is a viral genus belonging to the family Picornaviridae. The genus is comprised of two species, Aichi virus and Bovine kobuvirus, each possessing a single serotype. Aichi virus infects man (1,2), while bovine kobuvirus (3), as suggested by its name, infects cattle.

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Virus particles

The molecular mass of a typical virion particle of this genus is typically eight to nine million. The virions of the viruses in this genus consist of capsids that are 27 to 30 nm in diameter (1). The capsid is described as being round and displaying icosahedral symmetry. The capsid is believed to consist of 12 capsomers and the capsid shell structure of these virions has a monolayer composition (1). Using conventional electron microscopy, the structure of the capsid surface can be visualised (1,2). The virus particles contain a single species of ssRNA. These virions have a sedimentation coefficient of 140-165 S20w. The particles are described to be “relatively stable” in vitro (in comparison to other viruses) and stable in acidic conditions of pH 3.5 (2). They have also been found to be insensitive to treatment with some chemicals including chloroform, ether and non-ionic detergents (2).

Genetics

The viruses in this genus have single-stranded, linear non-segmented, positive-sense RNA genomes with lengths of approximately 8.2-8.3 kb (2,3).

References

(1) Yamashita, T., S. Kobayashi, K. Sakae, S. Nakata, S. Chiba, Y. Ishihara, and S. Isomura. 1991. Isolation of cytopathic small round viruses with BS-C-1 cells from patients with gastroenteritis. J. Infect. Dis. 164:954–957.

(2) Yamashita, T., Sakae, K., Tsuzuki, H., Suzuki, Y., Ishikawa, N., Takeda, N., Miyamura, T. and Yamazaki, S. (1998). Complete nucleotide sequence and genetic organization of Aichi virus, a distinct member of the Picornaviridae associated with acute gastroenteritis in humans. J. Virol. 72: 8408-8412.

(3) Yamashita, T., Ito, M., Kabashima, Y., Tsuzuki, H., Fujiura, A. and Sakae, K. (2003). Isolation and characterization of a new species of kobuvirus associated with cattle. J. Gen. Virol. 84: 3069-3077.