Phylodynamic analysis of porcine circovirus type 2 reveals global waves of emerging genotypes and the circulation of recombinant forms

Franzo, G., Cortey, M., Segalés, J., Hughes, J. and Drigo, M. (2016) Phylodynamic analysis of porcine circovirus type 2 reveals global waves of emerging genotypes and the circulation of recombinant forms. Molecular Phylogenetics and Evolution, 100, pp. 269-280. (doi: 10.1016/j.ympev.2016.04.028) (PMID:27114187)

Abstract

Since the first description of Porcine circovirus type 2 (PCV2), four genotypes (PCV2a, PCV2b, PCV2c and PCV2d) have been recognized and three of them have been shown to exhibit worldwide distribution. Here, the population dynamics of PCV2 has been reconstructed over time and the factors that have shaped its evolution determined. The results obtained confirm that PCV2 originated approximately at the beginning of the 20th century. The most recent common ancestor of genotypes PCV2a, PCV2b, PCV2c and PCV2d circulated in the 1950s, 1980s, 1960s and 1950s, respectively, and the population sizes of the individual genotypes remained low until the mid 90s, coinciding with the identification of PCV2 as a major pathogen of the pig industry. The population dynamics of PCV2 have been characterized by the appearance of periodic waves of distinct genotypes that, after an initial rise, spread following major swine commercial routes and were then superseded by subsequent emerging genotypes. Various recombinant forms displayed comparable population dynamics and spreading routes to those of major genotypes, suggesting that recombinant strains are able to compete with parental ones. The capsid gene is subjected to immune selection and evasion of the host immune response seems to be a major force for the emergence and spread of new genotypes. In contrast, the evolution of other genes appears to be constrained by the particular genomic organization of PCV2. In summary, obtained results suggest that changes in farming strategies, international trade, host population immunity, recombination and the constraints imposed by genome organization have all played a major role in the evolutionary dynamics of PCV2.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hughes, Dr Joseph
• Authors: Franzo, G., Cortey, M., Segalés, J., Hughes, J., and Drigo, M.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
• Journal Name: Molecular Phylogenetics and Evolution
• Publisher: Elsevier
• ISSN: 1055-7903
• ISSN (Online): 1095-9513
• Published Online: 23 April 2016
• Copyright Holders: Copyright © 2016 Elsevier
• First Published: First published in Molecular Phylogenetics and Evolution 100:369-280
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher