bovine herpesvirus 1

Preferred Scientific Name

• bovine herpesvirus 1

International Common Names

• English: infectious bovine rhinotracheitis virus

English acronym

• BoHV-1
• IBRV

• Domain: Virus
•     Group: "ssDNA viruses"
•         Group: "DNA viruses"
•             Order: Herpesvirales
•                 Family: Herpesviridae
•                     Genus: Varicellovirus
•                         Species: bovine herpesvirus 1

BHV-1 belongs to the family Herpesviridae, subfamily Alphaherpesvirinae, genus Varicellovirus. BHV-1 is an enveloped virus with an icosahedric capsid made of 162 capsomeres (Schwyzer and Ackermann, 1996). BHV-1 is a double-stranded DNA virus, 135-140 kbp in size (Mayfield et al., 1983; Wyler et al., 1989). At least ten glycoproteins are present on the envelope. They can be differentiated into glycoproteins essential for virus replication like gB, gD and gH, and non essential glycoproteins like gC, gE and gI (Baranowski et al., 1996). The three major glycoproteins, i.e. the most abundant ones in the virion, are gB, gC and gD.

The virus exhibits a tropism for epithelial cells, blood mononuclear cells and neurones. Virus replication takes place in the nucleus of the infected cell.

BHV-1 has two subtypes, called subtype 1 and 2, which can be characterized by the restriction endonuclease profiles of viral DNA (Engels et al., 1987), and by a few discriminating monoclonal antibodies (Metzler et al., 1985; Rijsewijk et al., 1999). All BHV-1 strains are very close, both antigenically and genomically. Since the 1970s, strains of subtype 1 have mainly been isolated from the respiratory tract (IBR strains). Strains of subtype 2 are mainly genital viruses, which had been isolated before the 1970s (Edwards et al., 1990). However, the subtype distinction does not segregate all the respiratory strains from the genital isolates. Strains isolated from aborted foetuses mainly belong to subtype 1 (Pauli et al., 1984; Miller et al., 1991). Whatever the vaccine strain used, each subtype will successfully protect against the other one.

Previously, BHV-1 subtype 3 was assigned a virus species and is now called BHV-5 or bovine encephalitis herpesvirus (Brake and Studdert, 1985).

BHV-1 strains can also be distinguished on the basis of their virulence. Hypervirulent and attenuated strains have been characterized by the induced clinical signs in experimentally infected animals (Kaashoek et al., 1996). However, the virulence character cannot be linked to a biochemical marker.

Several alphaherpesviruses isolated from other ruminant species are closely related to BHV-1: caprine herpesvirus 1 (CapHV-1) (Engels et al., 1987), cervine herpesvirus 1 (CerHV-1) (Inglis et al., 1983), rangiferine herpesvirus 1 (RanHV-1) (Ek-Kommonen et al., 1986) and buffalo herpesvirus (Brake and Studdert, 1985). Recently, a herpesvirus related to BHV-1 was also isolated from elk (Deregt et al., 2000).

Disease(s) associated with this pathogen is/are on the list of diseases notifiable to the World Organisation for Animal Health (OIE). The distribution section contains data from OIE's Handistatus database on disease occurrence. Please see the AHPC library for further information from OIE, including the International Animal Health Code and the Manual of Standards for Diagnostic Tests and Vaccines. Also see the website: www.oie.int.