Evolution of Bovine herpesvirus 4: recombination and transmission between African buffalo and cattle

Abstract

Bovine herpesvirus 4 (BoHV-4) has been isolated from cattle throughout the world, but virological and serological studies have suggested that the African buffalo is also a natural host for this virus. It has previously been found that the Bo17 gene of BoHV-4 was acquired from an ancestor of the African buffalo, probably around 1?5 million years ago. Analysis of the variation of the Bo17 gene sequence among BoHV-4 strains suggested a relatively ancient transmission of BoHV-4 from the buffalo to the Bos primigenius lineage, followed by a host-dependent split between zebu and taurine BoHV-4 strains. In the present study, the evolutionary history of BoHV-4 was investigated by analysis of five gene sequences from each of nine strains representative of the viral species: three isolated from African buffalo in Kenya and six from cattle from Europe, North America and India. No two gene sequences had the same evolutionary tree, indicating that recombination has occurred between divergent lineages; six recombination events were delineated for these sequences. Nevertheless, exchange has been infrequent enough that a clonal evolutionary history of the strains could be discerned, upon which the recombination events were superimposed. The dates of divergence among BoHV-4 lineages were estimated from synonymous nucleotide-substitution rates. The inferred evolutionary history suggests that African buffalo were the original natural reservoir of BoHV-4 and that there have been at least three independent transmissions from buffalo to cattle, probably via intermediate hosts and-at least in the case of North American strains-within the last 500 years. An independent observation supports the role of the African buffalo as the original host species of BoHV-4. The GenBank/EMBL/DDBJ accession numbers for the nucleotide sequences determined in this work are AY847305-AY847311 and AY847322-AY847348. Supplementary tables with primer details and GenBank accession numbers for the BoHV-4 sequenced regions are available in JGV Online.

Coinfection with Two Closely Related Alphaherpesviruses Results in a Highly Diversified Recombination Mosaic Displaying Negative Genetic Interference

“…With regard to the low rate of nucleotide substitution, recombination can be seen as an evolutionary driving force increasing the probability of a rare nonsynonymous mutation spreading within a herpesvirus species (44,45). In accordance with this hypothesis, recently reported phylogenetic evidence demonstrated both the high degree of gene conservation in natural herpesvirus populations and the emergence and spread of several natural recombinants in herpesvirus species that infect humans (1,24,25,29,(33)(34)(35)37) and animals (8,18,36). …”

Herpesvirus bovino 4 (BoHV-4): aspectos generales de su biología y situación en la República Argentina

“…Además, se postula que el proceso evolutivo del herpesvirus incluyó recombinaciones entre cepas divergentes, y que la evolución del gen Bo17 ocurrió independientemente de la evolución del genoma viral en su conjunto. La transmisión del BoHV-4 desde el búfalo africano al antecesor del ganado bovino no se produjo de manera directa, sino que probablemente ha involucrado a especies hospedadoras intermediarias, considerando que el Bos primigenius fue encontrado solo en Eurasia y África del Norte, mientras que el búfalo africano estaba restringido al África subsahariana 20 .…”

“…En contraste con la mayoría de los gammaherpesvirus, el BoHV-4 presenta la capacidad de replicar en un amplio rango de especies 48 , entre las que se encuentran el bisonte americano, el búfalo africano, diferentes especies de ciervos, cabras, ovejas, especies no rumiantes como el león, el gato doméstico y el conejo 20,38,45,54,56,59,73 , y una gran variedad de cultivos celulares incluyendo líneas celulares y cultivos primarios de células de bovino, ovino, caprino, canino, felino, porcino, conejo y pollo, así como en varias líneas celulares de humano 26,39,49,58 .…”

“…Si bien no se ha reconocido como agente causal de una entidad patológica específica, se asocia mayormente con infecciones del tracto reproductivo de los bovinos, particularmente durante el período posparto 17 . Aunque se detecta principalmente en el ganado bovino, también se ha identificado en otras especies, incluso no rumiantes, domésticas y silvestres 20,38,54,56,59,73 .…”

Tissular Distribution of Argentinean Strains of Bovine Herpesvirus Type 4 (BoHV-4) in Experimentally-Infected Calves

“…BoHV-4 has been isolated from cattle with respiratory infections, vulvovaginitis, mastitis, abortions, endometritis and apparently healthy animals throughout the world (Wellemans et al 1986, Miyano et al 2004, Izumi et al 2006, Bilge-Dagalp et al 2010, 2012. lions, domestic cats and rabbits (Kruger et al 2000, Lin et al 2000, Kálmán & Egyed 2005, Dewals et al 2006. Previous works carried on natural-and experimentally-infected animals have…”