Detection of a novel circovirus – PCV3
Detection of a novel porcine circovirus – PCV3 – by UMN VDL diagnosticians and researchers and others was recently reported in the journal Virology. The paper describes tissue lesions in pigs that were associated with PCV3 infection.
The UMN VDL has run a PCV3 PCR in its development lab and results indicate that PCV3 isn't a new infection but has been circulating undetected. We know little more than this about the virus but will continue to investigate and accumulate findings. The significance - if any - of PCV3 as a common and relevant agent of disease in pigs is not apparent at this time. Challenge studies have not been conducted and so all of the questions normally answered by a pathogenesis study are unknown. Please contact us if you have questions.
See the following abstract of the article:
Background: Porcine circovirus 2 causes different clinical syndromes resulting in a significant economic loss in the pork industry. Three pigs with unexplained cardiac and multi-organ inflammation that tested negative for PCV2 and other known porcine pathogens were further analyzed.
Methods: Histology was used to identify microscopic lesions in multiple tissues. Metagenomics was used to detect viral sequences in tissue homogenates. In situ hybridization was used to detect viral RNA expression in cardiac tissue.
Results: In all three cases we characterized the genome of a new circovirus we called PCV3 with a replicase and capsid proteins showing 55 and 35 % identities to the genetically-closest proteins from a bat-feces associated circovirus and were even more distant to those of porcine circovirus 1 and 2. Common microscopic lesions included non-suppurative myocarditis and/or cardiac arteriolitis. Viral mRNA was detected intralesionally in cardiac cells. Deep sequencing in tissues also revealed the presence of porcine astrovirus 4 in all three animals as well as rotavirus A, porcine cytomegalovirus and porcine hemagglutinating encephalomyelitis virus in individual cases.
Conclusion: The pathogenicity and molecular epidemiology of this new circovirus, alone or in the context of co-infections, warrants further investigations.
Others have reported similar lesions associated with the PCV3 virus.