Phylogenetic Analysis and Serological Investigation of Porcine Circovirus Indicates Frequent Infection with Various Subtypes

Figures

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  Figure 1. The geographical distribution of samples from Sichuan Province. The number of samples ranged from 3 to 211 (A). The number of positive samples detected via SYBR Green-based real-time PCR assay (B).

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  Figure 2. ML trees of PCV2 ORF2 gene. Scale bar: 0.1. (A) ML tree of ORF2 from PCV2 strains before 2009 (model: TN93 + G4). (B) ML tree of ORF2 from PCV2 strains during 2009–2016 (model: TIM3 + R4). (C) ML tree of ORF2 from PCV2 strains during 2017–2018 (model: TIM3 + R3). (D) ML tree of ORF2 from PCV2 strains after 2019 (model: TIM3 + R3). (E) ML tree of PCV3 ORF2 gene. Scale bar: 0.01 (model: TN93 + R3).

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  Figure 3. Amino acid sequence alignment of PCV2 (A) and PCV3 (B) in Cap protein. The black boxes show the residues’ deletion or frameshift mutation. The conserved amino acid sites are marked with the red background and blue boxes.

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  Figure 4. Expression and identification of PCV2, PCV3 and PCV4 Cap protein. PCV2a, 2b, 2d, PCV3a, PCV3b and PCV4 Cap proteins were identified via Western blot using anti-Strep tag antibody (A) and PCV2-, PCV3- and PCV4-positive sera (B). −: negative control, a, b, d: sub genotype of PCV2 and PCV3.

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  Figure 5. Seroprevalence of antibodies in 2019 and 2021. The OD450 values of all serum samples (n = 165) are displayed as a heatmap (A), and the total number of positive samples are shown in a Venn diagram (B). The distribution dot plot showed the positive rate of each antigen (C), while the annual positive rate is shown in a bar chart (D).