|Group:||Group IV ((+)ssRNA)|
Erbovirus is a viral genus of the Picornaviridae family. Viruses belonging to the Erbovirus genus have been isolated in horses with acute upper febrile respiratory disease. The structure of the erbovirus virion is icosahedral, having a diameter of 27-30 nm.
The virion essentially is a nucleocapsid that is visible under an electron microscope and is able to infect cultured cells from a broad range of mammals including rabbit kidney (RK13), African green monkey kidney (Vero), equine foetal kidney (EFK), and is able to infect humans.
The RNA genome of the virion is inside the capsid that is composed by twelve capsomers, which are cup-shaped pentamers.
Erbovirus, as a typical picornavirus, has a single-stranded positive-sense RNA genome. A feature of the picornavirus genome is the virus protein that is linked at the 5’ end of the genome, known as "VPg" (Virus-Protein-attached-to-the-Genome). In addition, the 3’ end of the genome has a poly-A tail. The transcription of the erbovirus genome gives rise to a polyprotein which is further more processed and cleaved to give the mature viral proteins, in order from 5' to 3' : L ("Leader"), VP4, VP2, VP3, VP1, 2A, 2B, 2C, 3A (Vpg), 3B, 3Cpro, 3Dpol.
The type (and only) species of the Erbovirus genus is Equine rhinitis B virus which was recently found to have three phylogenetically distinct serotypes, equine rhinitis B virus (ERBV)-1, ERBV-2 and ERBV-3. One such phylogenetic group was found to mostly comprise of "acid stable" virus isolates, surviving pH 3.6 for 1 hour at room temperature.
ERBV's appear to infect most foals and weanlings, eliciting a low serum antibody response in stark contrast to equine rhinitis A virus (ERAV), which is the only species of the genus Aphthovirus that is not a foot-and-mouth disease virus (FMDV), and appears to only infect horses once they begin training for racing (approx. 2 years old). ERAV enters the blood and elicits a very high serum antibody response that seems to then limit the spread of the virus by herd-immunity, given that only approximately 40% of horses have detectable ERAV antibody. The low serum antibody response of ERBV appears to allow the continual, seasonal re-infection of horses. Horses are also known to shed ERBV for up to two years, possibly more.
- ↑ 1.0 1.1 1.2 1.3 "Notes on Genus: Erbovirus". dpvweb. http://www.dpvweb.net/notes/showgenus.php?genus=Erbovirus. Retrieved 2007-03-16.
- ↑ Dynon K, Black W, Ficorilli N, Hartley C, Studdert M (2007). "Detection of viruses in nasal swab samples from horses with acute, febrile, respiratory disease using virus isolation, polymerase chain reaction and serology". Aust Vet J 85 (1-2): 46–50. doi:10.1111/j.1751-0813.2006.00096.x. PMID 17300454.
- ↑ 3.0 3.1 3.2 "'Erbovirus'". ICTVdb. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.052.0.07.htm. Retrieved 2007-03-16.
- ↑ Kriegshäuser G, Deutz A, Kuechler E, Skern T, Lussy H, Nowotny N (2005). "Prevalence of neutralizing antibodies to Equine rhinitis A and B virus in horses and man". Vet Microbiol 106 (3-4): 293–6. doi:10.1016/j.vetmic.2004.12.029. PMID 15778036.
- ↑ Wutz G, Auer H, Nowotny N, Grosse B, Skern T, Kuechler E (1996). "Equine rhinovirus serotypes 1 and 2: relationship to each other and to aphthoviruses and cardioviruses". J Gen Virol 77 ( Pt 8): 1719–30. doi:10.1099/0022-1317-77-8-1719. PMID 8760418.
- ↑ Black W, Studdert M (2006). "Formerly unclassified, acid-stable equine picornaviruses are a third equine rhinitis B virus serotype in the genus Erbovirus". J Gen Virol 87 (Pt 10): 3023–7. doi:10.1099/vir.0.81937-0. PMID 16963761.
- ↑ Black W, Hartley C, Ficorilli N, Studdert M (2005). "Sequence variation divides Equine rhinitis B virus into three distinct phylogenetic groups that correlate with serotype and acid stability". J Gen Virol 86 (Pt 8): 2323–32. doi:10.1099/vir.0.80778-0. PMID 16033980.
- ↑ Black W, Wilcox R, Stevenson R, Hartley C, Ficorilli N, Gilkerson J, Studdert M (2007). "Prevalence of serum neutralising antibody to equine rhinitis A virus (ERAV), equine rhinitis B virus 1 (ERBV1) and ERBV2". Vet Microbiol 119 (1): 65–71. doi:10.1016/j.vetmic.2006.08.031. PMID 17046179.