ORIGINAL ARTICLE Distribution and genetic diversity of porcine hokovirus in wild boars Da ´niel Cadar • Attila Csa ´gola • Ma ´rta L} orincz • Kata Tomba ´cz • Marina Spı ˆnu • Tama ´s Tuboly Received: 24 June 2011 / Accepted: 15 September 2011 / Published online: 1 October 2011 Ó Springer-Verlag 2011 Abstract Porcine hokovirus (PHoV), a newly discovered member of the family Parvoviridae and the proposed genus Hokovirus, is considered phylogenetically distinct from other parvoviruses. Here, we report a comprehensive spa- tio-temporal study of PHoV infection in Romanian wild boars. The prevalence of PHoV differed significantly in samples from 2006/2007 (22.76%) and 2010/2011 (50.54%), and also increased with age. Sequence analysis of PHoVs from 2006/2007 showed a close relationship to PHoVs from pigs from England and wild boars from Germany, while the PHoVs from 2010/2011 were mostly similar to isolates from Hong Kong. The most variable regions were detected in the NS1 gene and proved to be suitable for analysis of the genetic diversity of the virus. It was observed that PHoVs from older wild boar samples differed from those collected recently. These results sug- gested that porcine hokovirus could be a newly emerging virus of both domestic and wild pigs with yet unknown implications. Introduction Members of the family Parvoviridae are small, icosahe- dral, non-enveloped viruses with linear, single-stranded DNA genomes. The family, based on host range, is cur- rently divided into two subfamilies: the subfamily Par- vovirinae, whose members infect vertebrates, includes five genera, namely Dependovirus, Erythrovirus, Amdovirus, Bocavirus and Parvovirus, whereas members of the sub- family Densovirinae are present in insects and other arthropods [7]. The genomes contain two major open reading frames (ORFs) encoding the non-structural and the capsid proteins. During the last few years, a number of previously unknown parvoviruses have been detected, such as human and porcine bocaviruses (HBoV and PBoV) belonging to the genus Bocavirus [2, 4, 5, 7, 10, 11, 13, 14]. Furthermore, new viruses of swine and cattle were discovered in Hong Kong in 2008 [9], and the addition of a tentative genus, Hokovirus, to the subfamily Parvovirinae has been proposed [9]. Comparative sequence and phylogenetic analysis showed that the gen- omes of the novel porcine and bovine hokoviruses (PHoV and BHoV) were most similar to those of the newly described human parvovirus types 4 and 5 (PARV4/5), forming a distinct cluster within the parvoviruses. They also differed from other parvoviruses by their relatively large predicted VP1 protein and the presence of a unique small putative protein [9]. The latest taxonomic report by the International Committee on Taxonomy of Viruses [7] does not include these viruses or the suggested genus Hokovirus in the family Parvoviridae, nor are they listed among the proposed tentative members. Based on the observations of Lau et al. [9] about the genomic organi- zation of PHoV, Cheung et al. [6] have suggested that porcine hokovirus (PHoV) should be classified as porcine parvovirus type 3 (PPV3). Considering that, until now, no official taxonomic classification of the virus is available, we will refer to it as porcine hokovirus (PHoV), as pro- posed by Lau et al. [9]. D. Cadar (&) Á M. Spı ˆnu Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Manastur 3-5, Box 400372, Cluj-Napoca, Romania e-mail: dimmuvet@yahoo.com A. Csa ´gola Á M. L} orincz Á K. Tomba ´cz Á T. Tuboly Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent Istva ´n University, Hunga ´ria krt. 23-25, Budapest, Hungary 123 Arch Virol (2011) 156:2233–2239 DOI 10.1007/s00705-011-1125-6