Porcine Circovirus 3 Infection Research Articles

Detection and sequencing of porcine circovirus 3 in commercially sourced laboratory mice.

Porcine circovirus 3 (PCV3), a recently discovered virus, has spread widely in pigs throughout the world. In order to investigate the possibility of mice used to study the infection of PCV3, commercially sourced Balb/C and ICR mice were screened for PCV3 infection. Blood samples were collected from 20 mice (10 each of Balb/c and ICR), DNA was extracted, and subjected to PCR with PCV3 specific primers. We found all 20 serum samples tested positive for PCV3 DNA. From four mice, the complete genomes of PCV3 were amplified and sequenced, and a phylogenetic tree was constructed. The results showed that the amplified genome was 2000 bp, and sequence comparison showed that the homology of the complete genome and ORF2 gene with those of porcine PCV3 are 97.9%–98.8% and 96.9%–98.3%, respectively. Amino acids alignment results showed that the Cap protein of the mouse PCV3 isolates share 90.7%–96.3% amino acid homology with that of the references strains derived from pigs. Phylogenetic analysis based on ORF2 sequences showed that all PCV3 strains clustered together and were clearly separate from other circovirus species. We detected PCV3 in experimental mice in China for the first time, which is an opportunity to use mice to study the infection of PCV3 and a potential hazard to swine industry.

Porcine circovirus 3 is highly prevalent in serum and tissues and may persistently infect wild boar (Sus scrofa scrofa).

Porcine circovirus 3 (PCV‐3) prevalence has been minimally investigated in wild boar; dynamics of infection and viral tissue distribution are currently unknown. In this study, serum samples from 518 wild boar (from years 2004 to 2018) were used to study frequency of infection. Also, serum samples from 19 boar captured and recaptured at least two times for a period of time from 1 month to 1 year were collected to determine PCV‐3 infection dynamics. Finally, to elucidate PCV‐3 DNA organic distribution, sera, different tissues and faeces were obtained from 35 additional wild boar. PCV‐3 DNA was extracted and amplified with a conventional PCR. For the PCV‐3 PCR‐positive sera from the longitudinally sampled and different tissue types, a quantitative PCR was performed. Genome sequence was obtained from a number of PCV‐3 PCR‐positive samples from different years, different time‐points of infection and tissues. Obtained results confirmed the susceptibility of wild boar to the virus, showing high frequency of PCV‐3 detection (221 out of 518, 42.66%) and demonstrating circulation at least since 2004. Compiled data indicate the possibility of long‐term infections, since 5 out of 10 PCV‐3 PCR‐positive boars longitudinally sampled showed positivity in samplings separated for more than 5 months. All tested tissue types’ harboured PCV‐3 genome, with the highest percentage of PCR positivity in submandibular lymph node, tonsil, lung, liver, spleen and kidney. The amount of DNA in all tested PCV‐3 PCR‐positive samples was moderate to low. All partial and complete PCV‐3 sequences obtained from wild boar displayed high nucleotide identity, higher than 98%. In conclusion, this study further confirms that wild boar is susceptible to PCV‐3 infection, showing high frequency of detection in this animal species. Furthermore, PCV‐3 can be found in different tissues of wild boar and is apparently able to cause persistent infection.