First identification of porcine parvovirus 7 in China

Abstract

Porcine parvovirus (PPV) are small, non-enveloped and single-stranded DNA viruses, taxonomically classifiable within the family Parvoviridae. Seven PPV genotypes (PPV1 to PPV7) have been identified to date. PPV7, the most recently discovered PPV genotype, was first reported in US pigs in 2016. To explore PPV7 status in Chinese pig populations a total of 64 serum samples collected from two commercial farms in Guangdong province in 2014 were analyzed. PPV7 DNA was detected in 32.8% (21/64) of tested samples. On the porcine circovirus type 2 (PCV2) positive farm, the prevalence rate of PPV7 was 65.5% (19/29) which was significantly higher than that on the PCV2 negative farm (2/35, 5.7%), indicating a possible association between PCV2 and PPV7 infections. The sequences of three PPV7 strains were determined. Phylogenetic analysis revealed that the identified PPV7 strains circulating in China shared 98.7%-99.7% nucleotide homology with the US strain. Further sequence comparison analysis indicated that GD-2014-2 and GD-2014-3 possess a consecutive 9-nt deletion in the VP gene. This is the first report of the existence of PPV7 in China and this finding will strengthen understanding of the epidemiology of porcine parvovirus in Chinese pigs.

Çin’in Fujian Eyaletinde Domuz Parvovirus 7 (PPV7) İzolatlarının Genetik Karakterizasyonu

“…Based on sequence analysis of complete coding regions, the sequenced sequences (PPV7 FJFZ2017 and PPV7 FJLY2017) shared 99.7% nucleotide similarity with each other, shared 98.8% and 99.0% with PPV7 strain 42 [6] which was first identified in the US swine, shared 98.5% to 99.0% with PPV7 strains (GD-2014-1, GD-2014-2 and GD-2014-3) [9] which were first identified in Southern China. Phylogenetic analysis based on genome sequences under the family Parvoviridae (subfamily: Densovirinae and Parvovirinae) indicated that all the PPV7 isolates, together with TuPV and RPV2, were formed a distinct cluster (Chapparvovirus), different with other porcine parvoviruses.…”

“…Previously study also demonstrated that Chapparvovirus still have unclear species. PPV7 was firstly discovered by metagenomic sequencing from porcine rectal swabs of healthy adult pigs in the USA, in 2016 [8] , then was identified in Guangdong Province in southern China [9] with no significant clinical signs observed. In this study, we sequenced and analysis the PPV7 isolates from lung tissues in Fujian, which help us to understand the genetic diversity of porcine parvoviruses in China.…”

“…Recently, a novel genus parvoviruses (proposed Chapparvovirus) has been discovered from turkeys [5] , Eidolon helvums [6] , wild rats [7] and pigs (namely porcine parvovirus 7, PPV7) [8,9] . Previously study also demonstrated that Chapparvovirus still have unclear species.…”

“…The eluted DNAs were stored at -20°C until PCR detection. The presence of PPV7 DNA was initially detected by PCR with primers (PPV7-3434-F and PPV7-3654-R, see Table 1) targeting a 241 bp fragment of the VP gene as described previously [9] . The amplifications were performed using 2×TransTaq-T PCR SuperMix (+dye) (Transgen Biotek, Beijing, China) in a 50 µL PCR reaction containing 25 µL of 2X TransTaq-T PCR SuperMix, 1 µL PPV7-3434-F and PPV7-3654-R primer (10 µM each), 2 µL of the extracted DNA and 21 µL of PCR-grade water under the following conditions: denaturation for 5 min at 94°C followed by 35 cycles of 94°C for 30 sec, 56°C for 30 sec and 72°C for 30 sec, then with a final extension step at 72°C for 10 min.…”

“…Primers for genome sequencing (Table 1) were designed according to the similar strategy described previously [9] after optimized, with overlapped fragments encompassed the PPV7 genome. All the PCR positive samples' genomes were amplified by PCR technology.…”