Characterization of BoHV-5 field strains circulation and report of transient specific subtype of bovine herpesvirus 5 in Argentina
1 Virology Institute, Veterinary and Agricultural Science Research Centre (CICVyA), National Institute of Agricultural Technology (INTA), N. Repetto y Los Reseros S/N, CC25 (B1712WAA), Castelar, Buenos Aires, Argentina
2 Virology and Viral Diseases, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Boulevard de Colonster, 20, B43b, B-4000 Liège, Belgium
3 Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Rivadavia 1917 (C1033AAJ), Ciudad Autónoma de Buenos Aires, Argentina
4 Laboratorio Azul, Av. 25 de Mayo 479/485 (7300), Azul, Buenos Aires, Argentina
5 National University of the Center of Buenos Aires Province, Faculty of Veterinary Medicine, Department of Animal Health and Preventive Medicine, Virology Area, Paraje Arroyo Seco s/n, Tandil (7000), Buenos Aires, Argentina
BMC Veterinary Research 2011, 7:8 doi:10.1186/1746-6148-7-8Published: 7 February 2011
Bovine herpesvirus 5 (BoHV-5) is a member of the subfamily Alphaherpesvirinae responsible for meningo-encephalitis in young cattle. The first case of bovine meningo-encephalitis associated with a herpesvirus infection was reported in Australia. The current geographical distribution of BoHV-5 infection is mainly restricted to South America, especially Brazil and Argentina. Outbreaks of BoHV-5 are regularly observed in Argentina suggesting the circulation of the virus in the bovine population.
Seventeen field strains of BoHV-5 isolated from 1984 to now were confirmed by differential PCR and subjected to restriction endonuclease analysis (REA). Viral DNA was cleaved with BstEII which allows the differentiation among subtypes a, b and non a, non b. According to the REA with BstEII, only one field strain showed a pattern similar to the Argentinean A663 strain (prototype of BoHV-5b). All other isolates showed a clear pattern similar to the Australian N569 strain (prototype of BoHV-5a) consistent with the subtypes observed in Brazil, the other South-American country where BoHV-5 is known to be prevalent. The genomic region of subtype b responsible for the distinct pattern was determined and amplified by PCR; specifically a point mutation was identified in glycoprotein B gene, on the BstEII restriction site, which generates the profile specific of BoHV-5b.
This is the first report of circulation of BoHV-5a in Argentina as the prevailing subtype. Therefore the circulation of BoHV-5b was restricted to a few years in Argentina, speculating that this subtype was not able to be maintained in the bovine population. The mutation in the gB gene is associated with the difference in the restriction patterns between subtypes "a" and "b".