Prevalence of porcine circovirus type 3 in pigs in the southeastern Chinese province of Zhejiang

Abstract

Background Porcine circovirus type 3 (PCV3) was first reported in US in 2016. The virus was also identified later in China. Prevalence of PCV3 in Zhejiang province in southeastern China is not clear though it has been reported in many parts of China. Results PCV3 infection and its co-infection with other swine viral pathogens in pig herds of Zhejiang province were retrospectively investigated by quantitative PCR (qPCR) and its sero-prevalence by indirect ELISA. PCV3 was found positive in 67.1% of the 283 clinical samples taken from 2014 to 2017 as shown by qPCR. Single infection with PCV3 accounted for only one-third of the samples, and majority were of co-infections, predominantly with PEDV (41.6%) but generally low with other swine viruses. Indirect ELISA using the PCV3 capsid protein as the coating antigen revealed an average sero-positive rate of 52.6% (40.8 to 60.8%) in 2345 serum samples from 2011 to 2017, with earliest yet high positive findings in samples taken in 2012. Of 203 serum samples, the qPCR method showed more positive findings than ELISA (81.3% vs 56.2%). With 89 serum samples negative by ELISA, vast majority ( n = 81) were found positive by qPCR. There was negative correlation in levels of PCV3 DNA and anti-capsid antibody response. ORF2-based phylogenetic analysis revealed three major groups (PCV3a, PCV3b and PCV3c) of the 200 strains, 38 from this study and 162 reference strains from GenBank. Most of the strains from this study were clustered into PCV3c. Of the putative signature residues of the capsid protein (aa 24, 27, 77 and 150) relative to the three groups, only the PCV3a group strains showed a distinct pattern of residues VKSI (95% of the strains), while the other two groups did not have such a ‘signature’ pattern. Conclusions Results from this study provided further evidence that the novel virus PCV3 was widely distributed in China and might have emerged in Zhejiang province before 2014, most probably back in 2012 when there was high PCV3 sero-prevalence. PCV3 might be viremic in pigs and could spread by fecal shedding. Electronic supplementary material The online version of this article (10.1186/s12917-019-1977-7) contains supplementary material, which is available to authorized users.

Field infection of a gilt and its litter demonstrates vertical transmission and effect on reproductive failure caused by porcine circovirus type 3 (PCV3)

“…In this sense, farms can have variable ranges of PCV3 positivity within them; in our case, by PCR, we found that of 50 evaluated females, ten presented unique infection to PCV3 (20%). Reports in other geographical areas show that it is possible to find within a farm the presence of viral co-infections and unique infections with PCV3, which has been demonstrated by ELISA [ 33 ], PCR [ 34 – 36 ], qPCR [ 33 , 37 ], and metagenomic [ 18 ]. The most notable clinical manifestation in the studied farm was reproductive failures represented by decreased farrowing rate, increased stillbirth rate and mummy rate.…”

Recent Progress on Epidemiology and Pathobiology of Porcine Circovirus 3

“…Other porcine pathogens, especially viruses, co-infected with PCV3 were also found in healthy or sick pigs, such as PEDV, PRRSV, PCV4, pseudorabies virus (PRV), CSFV, and PPV, etc. [59][60][61][62][63][64][65][66][67][68][69]. PEDV is another common virus reported to be co-infected with PCV3 [59][60][61].…”

“…[59][60][61][62][63][64][65][66][67][68][69]. PEDV is another common virus reported to be co-infected with PCV3 [59][60][61]. Guo et al found that most of the 76 enteric samples collected from suckling piglets with severe diarrhea were mixed infection, and the co-infection rates of PCV2/PCV3, PCV2/PEDV, PCV3/PEDV were 69.74%, 57.89%, and 53.95%, respectively [59].…”

“…Guo et al found that most of the 76 enteric samples collected from suckling piglets with severe diarrhea were mixed infection, and the co-infection rates of PCV2/PCV3, PCV2/PEDV, PCV3/PEDV were 69.74%, 57.89%, and 53.95%, respectively [59]. Geng et al revealed that the PCV3 positive rate accounted for 67.1% of 283 clinical samples collected from 2014 to 2017 in pig herds of Zhejiang province, China [60]. The single infection rate of PCV3 was 30%, while the co-infection was the majority, mainly PEDV (41.6%) [60].…”

Establishment and Application of Dual TaqMan Fluorescence Quantitative Polymerase Chain Reaction (PCR) for the Detection of Porcine Circovirus Types 2 and 3

“…Retrospective research data demonstrated that PCV3 possessed a high sequence homology to bat circovirus, suggesting that PCV3 might have been derived early from bats and gradually adapted to pigs (Li et al 2018). In China, the infection rate of PCV3 is increasing in pig farms (Chen et al 2019;Geng et al 2019;Liu et al 2019;Xu et al 2018). Seriously, the positive rate of PCV2 and PCV3 co-infection in China is getting higher and higher (Guo et al 2020;Wang et al 2020a;Xia et al 2019;Zhang et al 2020).…”