Vaccinia virus: avaliação dadiversidade molecular e biológica de clones virais isolados de espécimes clínicos humanos e bovinos

Abstract

Vaccinia virus (VACV) played an important role for humanity because of its use during the smallpox eradication campaign. Furthermore, currently VACV has been widely used as a vector of the recombinant vaccines. Following smallpox eradication, other orthopoxviruses have emerged worldwide, such as Cowpox virus, Monkeypox virus and VACV. VACV is the etiologic agent of the bovine vaccinia (BV), an emerging zoonosis that has been associated with economic, social, veterinary and public health issues, mainly in Brazil. Despite the current and historical VACV importance, there is little information about its circulation, prevalence, origins and maintenance in the environment, natural reservoirs and diversity. Brazilian VACV (VACV-BR) are grouped into two groups, based on genetic and biological diversity: group 1 (G1) and group 2 (G2). G2 strains displays higher plaque sizes and are virulent to mice, unlike G1. Moreover, polymorphisms observed in VACV genes, such as A56R, A26L and C23L genes, have been used in phylogenetic studies and further confirmed the dichotomy between G1 and G2 VACV-BR. In this study, was investigated VACV clonal diversity from field samples, during BV outbreaks. The results demonstrated that the G1 VACV-BR viruses were more frequently isolated. Molecular and biological analysis corroborated previous reports and confirmed the co-circulation of two VACV-BR lineages. Furthermore, it was co-detect the two variants (G1 and G2) in a same sample. Two clones showed a mosaic profile, with both G1 and G2 features based on the molecular analysis of A56R, A26L and C23L genes, maybe as a result of an increased recombination rate in a mixed population. Indeed, some single nucleotide polymorphism (SNPs) and insertions and deletions (INDELs) in A56R nucleotide sequences were observed among clones of a given virus population. These results provide information about the diversity profile in VACV clones.