Research Article Molecular Phylogeny of Suid Herpesvirus 1 Antônio A. Fonseca Jr., 1 Érica B. Sales, 2 Marcos B. Heinemann, 2 and Jenner K. P. Reis 2 1 Laborat´ orio de Biologia Molecular, Laborat´ orio Nacional Agropecu´ ario – Lanagro/MG, Minist´ erio da Agricultura, Pecu´ aria e Abastecimento, Avenida Rˆ omulo Joviano s/n, Fazenda Modelo, 33600-000 Pedro Leopoldo, MG, Brazil 2 Escola de Veterin´ aria, Universidade Federal de Minas Gerais, Avenida Antˆ onio Carlos, 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil Correspondence should be addressed to Antˆ onio A. Fonseca Jr.; antonio.fonseca@agricultura.gov.br Received 12 September 2013; Accepted 8 January 2014; Published 10 April 2014 Academic Editors: M. Magnani, S. P¨ ohlmann, D. Shukla, and A. Vallinoto Copyright © 2014 Antˆ onio A. Fonseca Jr. et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pseudorabies is a disease that signifcantly impacts the swine industry. Tis disease is caused by Suid Herpesvirus 1 (SuHV-1), which is a double-stranded DNA virus that belongs to the Herpesviridae family and the Alphaherpesvirinae subfamily and exhibits a slow rate of genetic evolution. Te aim of this study was to use both full and partial sequences of SuHV-1 genes available in GenBank to examine the evolution and divergence of viruses isolated in diferent parts of the world. Partial and complete sequences of SuHV-1 genes were obtained either from GenBank (i.e., us6, us7, us8, us9, ul14, ul49.5, and ul44) or from genetic sequencing of Brazilian SuHV-1 samples. Te results of this study corroborate previous phylogenetic studies of SuHV-1 that demonstrated diferent evolutionary profles of isolates from diferent parts of the globe, with a rapid genetic dispersion of Chinese isolates. All of the phylogenetic trees generated in this study demonstrated a large genetic distance between SuHV-1 isolates from the Western and Eastern regions of the world. 1. Introduction Pseudorabies (PR) is a disease that signifcantly impacts the swine industry. Tis disease is caused by Suid Herpesvirus 1 (SuHV-1), which is a double-stranded DNA virus that belongs to the Herpesviridae family and the Alphaherpesvirinae subfamily and exhibits a slow genetic evolution. Te primary hosts of SuHV-1 are domestic or wild pigs (Sus scrofa). Tis disease also afects cows, dogs, and cats, but, in these species, the disease is fatal in nearly 100% of cases [1]. Although PR has been eradicated in domestic swine in many countries, such as the United States, Germany, and England, this disease still occurs in wild boars and other feral swine in these countries [2]. SuHV-1 has only one serotype and can be genetically typed using methods including whole genome enzymatic restriction with BamHI, which demonstrates the presence of four genomic types [3, 4]. However, most recent publications also use partial sequences of the ul44 gene to evaluate the genetic variation of SuHV-1 isolates [5–8]. Tis gene encodes glycoprotein C (gC), which is a protein that is considered to be a potent inducer of the immune response and the principal component of adhesion to host cell receptors [9]. Phylogenetic analysis of partial sequences of ul44 separates SuHV-1 into fve genotypes, with specifc clades that include sequences derived from viruses isolated from domestic pigs or wild boars [10]. Te us8 gene has also been used for phylogenetic analysis of SuHV-1 [6, 11, 12]. Tis gene is more conserved than ul44 but can also be used to detect genetic diferences between SuHV-1 isolates from diferent regions. us8 encodes glycoprotein E (gE). Although gE is not essential for viral replication, the absence of this protein reduces the virulence of the virus. us8 is frequently deleted in attenuated SuHV-1 vaccine strains [13]. Sequences from other SuHV-1 genes are available in GenBank, but these genes are not used in studies of genetic variability. Te herpesvirus genome is typically highly con- served [3] and even genes such as ul44 do not have sufcient variability to generate high-resolution phylogenetic trees [5– 8]. Other genes could also be used, and some genes that are involved in envelope formation could contain enough Hindawi Publishing Corporation ISRN Virology Volume 2014, Article ID 463173, 7 pages http://dx.doi.org/10.1155/2014/463173