<i>Equid alphaherpesvirus 1</i> from Italian Horses: Evaluation of the Variability of the <i>ORF30</i>, <i>ORF33</i>, <i>ORF34</i> and <i>ORF68</i> Genes

<i>Equid alphaherpesvirus 1</i> (EHV-1) is an important pathogen of horses. It is spread worldwide and causes significant economic losses. The <i>ORF33</i> gene has a conserved region that is often used as target in diagnostic PCR protocols. Single nucleotide point (SNP) mutations in <i>ORF30</i> are usually used to distinguish between neuropathogenic and non-neuropathogenic genotypes. An <i>ORF68</i> SNP-based scheme has been used for grouping different isolates. Recently, the highest number of variable sites in EHV-1 from the UK has been found in ORF34. In this study, EHV-1 positive samples from Italian horses with a history of abortion were investigated by amplifying and sequencing the <i>ORF30</i>, <i>ORF33</i>, <i>ORF34</i> and <i>ORF68</i> genes. Most animals were infected by the neuropathogenic type A2254G. A 118 bp deletion was found at nucleotide positions 701&#8722;818 of the <i>ORF68</i> gene, making impossible to assign the samples to a known group. Sequencing of the <i>ORF34</i> gene with a newly designed nested PCR showed new SNPs. Analysis of these sequences and of those obtained from genetic databases allowed the identification of at least 12 groups. These data add depth to the knowledge of EHV-1 genotypes circulating in Italy.