Parvovírus suíno tipo 1: dinâmica evolutiva e implicações para a eficácia vacinal

Abstract

Porcine parvovirus type 1 (PPV1) is one of the main etiological agents responsible for causing reproductive failures in swine farms, frequently associated with SMEDI syndrome (stillbirth, mummification, embryonic death and infertility), resulting in significant economic losses. Although vaccination is the main control measure, its high resistance and the emergence of new variants raise concerns about the efficacy of currently used commercial vaccines. The objective of this study was to investigate the evolutionary dynamics of PPV1 through an integrated approach between bioinformatics and immunoinformatics, evaluating antigenic divergence and its implications for vaccine protection. For this purpose, 200 complete VP2 gene sequences were analyzed, spanning the period from 1963 to 2021. The results revealed the existence of five distinct genetic lineages, of which two lack representation of reference vaccine strains, indicating possible failure in immunological coverage. A high evolutionary rate of 1.57 × 10- 5 substitutions/site/year was estimated, comparable to that of RNA viruses. Sites 320 and 436 of the VP2 protein were identified under strong positive selection pressure, and specific mutations in antigenic regions were correlated with antigenic drift and pathogenicity. Additionally, promising T-cell epitopes were identified with high binding affinity to SLA alleles. In conclusion, PPV1 exhibits genetically divergent lineages with immune escape potential. These findings highlight the need for continuous genomic surveillance and the updating of immunogens. [resumo fornecido pelo autor]