Porcine circovirus type 3 (PCV3) is a novel circovirus species recently discovered in USA and China in cases of porcine dermatitis and nephropathy syndrome, reproductive failure, respiratory disease and multisystemic inflammation. This study reports on the first identification of PCV3 in Europe, in serum from pigs from Polish farms. A total of 1,050 serum samples were collected between 2014 and 2017 from sows and 3-20 weeks old pigs from 14 commercial farms representing different regions of Poland, different size and health status. The samples were pooled by 4-6 and tested with real-time PCR for PCV3. PCV3 DNA was detected in 12 of 14 farms (85.7%). On the PCV3-positive farms, the virus was detected in 5.9% to 65% serum pools. PCV3 was most common among weaned pigs and finishers (26.1% and 28.0% of serum pools, respectively). Sequence analysis of 359 nucleotide fragment of ORF2 showed highest identity of 99.7% to PCV3-US/SD2016 from USA. Our results indicate that PCV3 is a common virus among Polish pigs but no links to unexplained disease conditions were established.

Porcine parvoviruses are small non-enveloped DNA viruses, very resistant to inactivation, and ubiquitous in the global pig population. Porcine parvovirus type 1 (PPV1) has been known since the 1960s and is a major causative agent of reproductive failure in breeding herds. During the last decade, several new parvoviruses have been identified in pigs by molecular methods and have been consecutively designated as PPV2 through PPV6. Epidemiology data for these viruses are limited, and the impact of these newly recognized parvoviruses on pigs is largely unknown. To further generate knowledge on the distribution of PPVs in pigs, a total of 247 serum samples were collected from six commercial Polish pig farms during 2013-2015 and tested by PCR assays and ELISAs. The pigs ranged from two to 18 weeks of age at sample collection. Breeding herds supplying the investigated farms were routinely vaccinated against PPV1. While all growing pig samples were negative for PPV1 DNA, young pigs were frequently negative for PPV1 antibodies and seroconversion to PPV1 was commonly seen at 9-10 weeks of age. The PPV2 antibody detection was highest in young pigs (2-6-week-old) and decreased in older pigs indicating passively acquired antibodies. The DNA prevalence rates in the serum samples analysed were 19% for PPV2, 7.7% for PPV3, 2.4% for PPV4, 4.0% for PPV5 and 6.1% for PPV6. Most PPV DNA-positive samples were identified in 9- to 18-week-old pigs with no obvious association with disease on the farm. All recently emerging PPV genotypes were detected in Polish farms. Similar to previous reports in other pig populations, PPV2 was the most frequent PPV genotype circulating in Poland.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most common infectious diseases of swine globally. Since the course of PRRS virus (PRRSV) infection is subclinical, laboratory diagnosis is necessary to detect the virus or specific antibodies. The aim of this study was to assess the sensitivity and specificity of IDEXX PRRS X3 Ab Test (IDEXX, USA), Civtest Suis E/S (Hipra, Spain), INgezim PRRS 2.0 (Ingenasa, Spain), VetExpert PRRS Ab ELISA 4.0 (BioNote, Korea), Pigtype PRRSV Ab (Qiagen, Germany) and PrioCHECK PRRSV Antibody ELISA (ThermoFisher, USA), using serum samples obtained from 5 conventional PRRSV-positive and 5 PRRSVnegative Polish pig farms. Specificity of ELISAs ranged from 94.2% (ThermoFisher) to 100% (IDEXX and Hipra). ThermoFisher ELISA had the highest detection rate and detected 67.2% samples from PRRSV-positive farms as positive but considering its low specificity some of the positive results may be incorrect. IDEXX ELISA considered as a reference detected 64.8% positive sera in PRRSV-positive farms. On the other hand Hipra Elisa identified only 51.8% of samples as positive. The diagnostic sensitivity of five ELISAs relative to IDEXX ranged from 80.3% (Hipra) to 96.3% (ThermoFisher). Our study showed significant differences in specificity and diagnostic sensitivity between the compared kits. The differences in the performance appeared to be practically negligible on farms where early infection with PRRSV occurred. However, on PRRSV-negative farms, or farms with PRRSV stable sow herds, some ELISAs can give results not reflecting the infection status in specific age groups.

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Porcine parvovirus type 1 is a major causative agent of swine reproductive failure. During the past decade, several new parvoviruses have been discovered in pigs. Porcine parvovirus type 6 (PPV6), recently identified, has been reported in pigs in China and in the USA while the PPV6 status in the European pig population remains undetermined. In the present study, PPV6 DNA was identified in serum samples collected from domestic pigs in Poland. In investigated herds, the prevalence of PPV6 was 14.9 % (15/101 samples). Sequencing was conducted, and 11 nearly complete PPV6 genomes were obtained. Phylogenetic analysis indicated that PPV6 sequences cluster into four distinct groups, and the Polish PPV6 strains from three individual farms were present in three of these four groups. In addition, the Polish PPV6 strain P15-1 was identified as a putative recombination of an ORF1 from US stains and an ORF2 from Chinese strains. This is the first identification of PPV6 in Europe, and this finding will encourage future epidemiological studies on parvoviruses in European pigs.Electronic supplementary materialThe online version of this article (doi:10.1007/s11262-016-1386-y) contains supplementary material, which is available to authorized users.