ORIGINAL ARTICLE Genetic characterization and phylogenetic analysis of porcine circovirus type 2 (PCV2) in Serbia Bozidar Savic • Vesna Milicevic • Dobrila Jakic-Dimic • Jovan Bojkovski • Radisa Prodanovic • Branislav Kureljusic • Aleksandar Potkonjak • Borivoje Savic Received: 9 July 2011 / Accepted: 18 September 2011 Ó Springer-Verlag 2011 Abstract Porcine circovirus type 2 (PCV2) is the main causative agent of postweaning multisystemic wasting syndrome (PMWS). To characterize and determine the genetic diversity of PCV2 in the porcine population of Serbia, nucleotide and deduced amino acid sequences of the open reading frame 2 (ORF2) of PCV2 collected from the tissues of pigs that either had died as a result of PMWS or did not exhibit disease symptoms were analyzed. Sequencing and phylogenetic analysis showed considerable diversity among PCV2 ORF2 sequences and the existence of two main PCV2 genotypes, PCV2b and PCV2a, with at least three clusters, 1A/B, 1C and 2D. In order to provide further proof that the 1C strain is circulating in the porcine popu- lation, the whole viral genome of one PCV2 isolate was sequenced. Genotyping and phylogenetic analysis using the entire viral genome sequences confirmed that there was a PMWS-associated 1C strain emerging in Serbia. Our anal- ysis also showed that PCV2b is dominant in the porcine population, and that it is exclusively associated with PMWS occurrences in the country. These data constitute a useful basis for further epidemiological studies regarding the het- erogeneity of PCV2 strains on the European continent. Introduction Porcine circovirus type 2 (PCV2) belongs to the family Circoviridae, genus Circovirus [31]. Among the various disease syndromes caused by PCV2, postweaning multi- systemic wasting syndrome (PMWS) is one that has become a global swine disease with a severe economic impact on the swine industry worldwide [1, 7, 12, 25, 26]. PCV2 has a circular single-stranded genome DNA [30], which contains three major open reading frames (ORF1, 2, 3). ORF1 encodes the replicase proteins involved in virus replication [20], ORF2 encodes the viral capsid protein [22], and ORF3 encodes a protein involved in PCV2- induced apoptosis in vitro [18]. Several genotyping studies have identified two distinct genotypes of PCV2 [2, 5, 11, 16, 21, 23, 29, 33], and a third genotype was identified in archived Danish samples [6]. To improve the usefulness of published names of PCV2 genotypes, the EU consortium on porcine circovirus diseases (www.pcvd.net) has pro- posed a unified nomenclature for PCV2 genotypes. The consortium proposes naming the three PCV2 genotypes PCV2a, PCV2b and PCV2c [27]. Using this system, ORF2 sequences of PCV2 are assigned to different genotypes when the genetic distance between them is at least 0.035 [27]. PCV2a is further subdivided into five clusters, 2A-2E, and PCV2b, into three clusters 1A-1C [23]. Several studies have reported a genetic shift from genotype PCV2a to PCV2b, linked to the occurrence of PMWS outbreaks in the USA and Canada in 2007, and in Europe in 2008 [3, 4, 6, 10]. Dupont et al. [6] have B. Savic (&)  V. Milicevic  D. Jakic-Dimic  R. Prodanovic  B. Kureljusic Department for Swine Diseases, Institute of Veterinary Medicine Belgrade, Vojvode Toze 14, 11 000 Belgrade, Serbia e-mail: sb.boban@sezampro.rs J. Bojkovski Faculty of Veterinary Medicine, University of Belgrade, B. Oslobodjena 18, 11000 Belgrade, Serbia A. Potkonjak Department for Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Dositej Obradovic Square 8, 21000 Novi Sad, Serbia B. Savic Clinical Center of Serbia, Visegradska 26, 11000 Belgrade, Serbia 123 Arch Virol DOI 10.1007/s00705-011-1130-9