Co-circulation and genetic characteristics of porcine circoviruses in postweaning multisystemic wasting syndrome cases in commercial swine farms

Danh Cong Lai; Duyen My Thi Nguyen; Toan Tat Nguyen; Tram Ngoc Thi Ngo; Duy Tien Do

doi:10.1007/s13337-023-00849-4

Co-circulation and genetic characteristics of porcine circoviruses in postweaning multisystemic wasting syndrome cases in commercial swine farms

Virusdisease. 2023 Dec;34(4):531-538. doi: 10.1007/s13337-023-00849-4. Epub 2023 Nov 11.

Authors

Danh Cong Lai^{1

2}, Duyen My Thi Nguyen¹, Toan Tat Nguyen¹, Tram Ngoc Thi Ngo¹, Duy Tien Do¹

Affiliations

¹ Faculty of Animal Science and Veterinary Medicine, Nong Lam University - HCMC (NLU), Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam.
² Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583 USA.

PMID: 38046060
PMCID: PMC10686971 (available on 2024-12-01)
DOI: 10.1007/s13337-023-00849-4

Abstract

This study aimed to investigate the co-infection and genetic characteristics of Porcine circoviruses in PMWS-affected pigs in five commercial farrow-to-finish swine farms in Vietnam. By the end of 2022, the percentage of PMWS-affected pigs in these farms has increased significantly compared to previous years. The lymph node samples from ten PMWS typical cases were randomly collected to test for the presence of PRRSV, PCV2, PCV3 and PCV4. While PRRSV and PCV4 were not found in these cases, 10 and 3 out of 10 samples were positive for PCV2 and PCV3, respectively. Three farms in the study showed the co-infection of PCV2 and PCV3 in affected pigs. Besides, all PCV-positive samples were sequenced to evaluate genetic characterization of PCVs in PMWS-affected cases. Phylogenetic analysis showed that all PCV3 strains in the study were clustered into PCV3b genotype. 8 out of 10 PCV2 strains belonged to PCV2d genotype while the remaining two strains belonged to PCV2b genotypes. Two farms had co-circulation of PCV2b and PCV2d genotypes in two different age groups of pigs, which is reported for the first time in Vietnam. Several amino acid substitutions were identified in important antigenic regions in the capsid protein of the PCV2 field strains compared to vaccine strains. Taken together, the results showed the high co-prevalence of PCV3 and PCV2, and the wide genetic diversity of PCV2 field and vaccine strains may be the cause of the increased PMWS situation in these pig farms.

Supplementary information: The online version contains supplementary material available at 10.1007/s13337-023-00849-4.

Keywords: Genetic analysis; Mutation; PCV2; PCV3; Porcine circovirus.

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