Detection and genetic analysis of a novel atypical porcine pestivirus from piglets with congenital tremor in Japan

Abstract

Atypical porcine pestivirus (APPV), which has been confirmed to be associated with congenital tremor (CT) in pigs, is a newly discovered porcine virus that has been found in the Americas, Europe, and Asia; however, no report of APPV in Japan has been published. We identified an APPV in the central nervous system of Japanese piglets with CT, and firstly determined and analyzed the complete genome sequence. Phylogenetic analysis using the complete genome nucleotide sequence of the Japanese APPV, named Anna/2020, and those of APPVs from the NCBI database showed that APPVs were divided into three genotypes (genotypes 1 to 3), and that Anna/2020 clustered with the genotype 3 APPV strains, but distantly branched from these strains. Pairwise complete coding region nucleotide sequence comparisons revealed that there was 94.0% to 99.7% sequence identity among the genotype 3 strains, while Anna/2020 showed 87.0% to 89.3% identity to those genotype 3 strains, suggesting that Anna/2020 represents a novel APPV lineage within genotype 3. Retrospective examinations using RT-PCR revealed one genotype 1 and two novel genotype 3 APPVs from pigs without CT, and that novel genotype 3 APPVs have been prevalent in Japan since at least 2007.

Detection and localization of atypical porcine pestivirus in the testicles of naturally infected, congenital tremor affected piglets

“…APPV was discovered in the United States in 2015, by metagenomic sequencing of a sample, which was real‐time quantitative reverse transcription PCR (qRT‐PCR) positive for porcine reproductive and respiratory syndrome virus (PRRSV) (Hause et al., 2015). To date, APPV has been identified in Germany (Beer et al., 2017; Postel et al., 2016), Sweden (Blomström et al., 2016), the Netherlands (de Groof et al., 2016), Austria (Schwarz et al., 2017), Spain (Muñoz‐González et al., 2017), China (Yuan et al., 2017), Great Britain, Italy (Postel et al., 2017), Brazil (Gatto, Harmon, et al., 2018), Hungary (Dénes et al., 2018), Canada (Dessureault et al., 2018), Switzerland (Kaufmann et al., 2019), Japan (Kasahara‐kamiie et al., 2021) and most recently in Denmark (Pedersen et al., 2021). APPV was also detected in wild boars in Germany and Serbia (Cagatay et al., 2018), suggesting that, similar to classical swine fever, wild boars may serve as a virus reservoir (Vilček & Nettleton, 2006).…”