Retrospective study of porcine circovirus type 2 infection reveals a novel genotype PCV2f

Abstract

Porcine postweaning multisystemic wasting syndrome (PMWS) caused by porcine circovirus type 2 (PCV2) is a disease causing severe economic losses annually worldwide to the pig industry. PCV2 infection was first reported in China in 2000, and currently has three major genotypes, PCV2a, b and d, circulating in this country. To further elucidate the origin and prevalence of PCV2 in China, 123 clinical pig tissue samples collected in 25 provinces between 1990 and 1999 were analysed by PCV2-specific PCR, resulting in identification of 23 PCV2 strains collected between 1996 and 1999. Phylogenetic analysis based on the nucleotide sequences of open reading frame 2 (ORF2) showed that 20 of the 23 grouped within PCV2a, while the remaining three strains formed an independent clade, so far unreported and therefore named PCV2f. This genotype shared lower sequence identity with other known genotypes. This study provides further understanding of the genetic diversity and evolution of PCV2 and has tracked PCV2 infection in China back to 1996 rather than 2000.

Retrospective study of porcine circovirus 3 infection in China

“…A retrospective analysis of PCV2 infection in China has also been performed with the same clinical samples of the present PCV3 study, with the earliest PCV2 case also being detected in 1996 (Bao et al., ). In the latter report, PCV2a and a novel genotype PCV2f were found circulating between 1996 and 1999 in China, with PCV2a dominant (20/23) (Bao et al., ).…”

“…A retrospective analysis of PCV2 infection in China has also been performed with the same clinical samples of the present PCV3 study, with the earliest PCV2 case also being detected in 1996 (Bao et al., ). In the latter report, PCV2a and a novel genotype PCV2f were found circulating between 1996 and 1999 in China, with PCV2a dominant (20/23) (Bao et al., ). Previous studies revealed that PCV2a was the earliest genotype of PCV2, with the time to the most recent common ancestor (TMRCA) estimated to be 1964 (1948–1974) (Franzo, Cortey, Segalés, Hughes, & Drigo, ) or 1966 (1945–1983) (Firth, Charleston, Duffy, Shapiro, & Holmes, ).…”

“…To test for coinfection with CSFV or PCV2, assays for CSFV and PCV2 were conducted as previously described (Bao et al., ; Paton et al., ).…”

“…Most recently, PCV2 infection has been traced back to 1996 in China (Bao et al., ), while the prevalence of PCV3 before 2015 remained unknown. In this study, a retrospective analysis of PCV3 infection in China was conducted by analysing samples collected from pigs between 1990 and 1999 in 20 provinces, five autonomous regions and four municipalities.…”

Molecular epidemiology and genetic variation analyses of porcine circovirus type 2 isolated from Yunnan Province in China from 2016-2019

“…For example, the recombinant cluster that recombines between PCV2a and PCV2b strains can occur in the Cap protein-coding region through different patterns and yield different recombinants [16]. In 2018, results from a retrospective analysis showed that a new genotype, PCV2f, was tracked to samples collected in 1996 in China [17]. Up to now, there is no specific treatment available for PCV2 infection and PCVADs.…”