Genetic diversity of porcine circovirus 3 strains and the first detection of two different PCV3 strains coinfecting the same host in Minas Gerais, Brazil

Phylogenetic analysis of porcine circovirus 3 circulating in Canadian pigs

Introduction

Porcine circovirus 3 (PCV3) has been detected in pigs worldwide and associated with several clinical signs.

Methods

To investigate the genetic diversity of PCV3 strains circulating in Canada, 44 PCV3 positive samples from Saskatchewan (2/44), Manitoba (2/44), Quebec (4/44), Alberta (11/44) and Ontario (25/44) submitted to diagnostic laboratories in Canada between 2019 and 2021 were sequenced and analyzed.

Results

Phylogenetic analysis of capsid genes showed that all of the 44 Canadian strains classified into PCV3a and segregated into seven lineages with common amino acid changes observed at A24V, R27K, N56D, T77S, Q98R, L150I (F) and R168K positions.

Conclusion

Future studies are required to determine whether the polymorphisms in capsid proteins, as revealed in this study, could be associated with differences in the pathogenicity or antigenicity of PCV3 strains. This is the first phylogenetic analysis of PCV3 strains among different provinces in Canada.

Recent Progress on Epidemiology and Pathobiology of Porcine Circovirus 3

The recently discovered porcine circovirus 3 (PCV3) belongs to the Circovirus genus of the Circoviridae family together with the other three PCVs, PCV1, PCV2, and PCV4. As reported, PCV3 can infect pig, wild boar, and several other intermediate hosts, resulting in single or multiple infections in the affected animal. The PCV3 infection can lead to respiratory diseases, digestive disorders, reproductive disorders, multisystemic inflammation, and immune responses. Up to now, PCV3 infection, as well as the disease caused by PCV3, has been reported in many swine farms worldwide with high positive rates, which indicates that the virus may be another important pathogen in the swine industry. Therefore, we reviewed the current progress on epidemiology and pathobiology of PCV3, which may provide the latest knowledge of the virus and PCV3-related diseases.

Porcine circovirus 3 in North and South America: Epidemiology and genetic diversity

Porcine circovirus 3 (PCV3) is a recently discovered virus that has been detected in the swine population worldwide. PCV3 infection has been associated with several signs, but its pathogenicity is currently uncertain. This review article aimed to analyse the PCV3 strains that circulate in different countries in North and South America. We demonstrated the main regions of polymorphisms in the capsid protein structure. Furthermore, we found that PCV3 has at least six different lineages circulating in the Americas. Additional studies are required to determine the role of PCV3 in different clinical syndromes and its epidemiology in swine herds in North and South American countries.