Veterinary/zoology session

Parvovirus infections of swine, with the classical porcine parvovirus (PPV) strains are widespread worldwide and are responsible for reproductive disorders, especially in those herds where vaccination protocols are not followed correctly or, where vaccine efficacy is decreased due to immunosuppressive factors. Thanks to the rapidly improving nucleic acid amplification technologies new porcine parvoviruses had been described during the last years. An unusual parvovirus was detected in pig sera in Myanmar, and provisionally named PPV2, as the genome was distantly related to previously known porcine parvovirus sequences. Later, during the year 2007 yet another parvovirus was described in pigs in Hong Kong and hence named porcine hokovirus (PHoV). PHoV was found to be genetically similar to the also recently described human parvovirus type 4 and 5 (PARV4, 5) and the bovine hokoviruses. The worldwide occurrence of these newly discovered swine parvoviruses is not known yet. The purpose of this study was to determine if hokoviruses were also present in Hungary, or they were only characteristic in the Hong Kong area, and if positive cases were identified, to determine the prevalence of PHoV in Hungary and compare the sequences with those available in the GenBank.

Organ samples (lungs, liver, kidneys, spleen and lymph nodes) were collected randomly at slaughterhouses and the Department of Pathology between 2006 and 2009. The samples were processed following standard nucleic acid purification methods and tested for the presence of hokovirus genomes by polymerase chain reaction (PCR) and sequencing. Primer pairs were synthesized for amplification and sequencing, and a different set of primers comprising a short region of 130 bases was designed for diagnostic purposes. PCR was carried out as a standard amplification procedure.

PCR results with the diagnostic primers indicated that 39% of the samples were positive for PHoV, similar to the prevalence already described by the original study in Hong Kong. No geographic differences could be detected in the prevalence of the virus, though comparing samples according to the year of collection, an increase could be shown between 2006 and 2009.