Caracterização molecular e biológica de amostras de vaccinia virus isoladas durante surtos de vaccinia bovina no Brasil

Abstract

The genus orthopoxvirus (OPV), belonging to Poxviridae family, comprises viruses with complex morphology, multiplication site in the cytoplasm and a large extensive genome of double-stranded DNA. The Vaccinia virus (VACV), member of this genus, is an important zoonotic agent, affecting mainly the milk and cattle milkers, which gives the disease an occupational character. Since 1999, the VACV has been linked to outbreaks of a disease called bovine vaccinia (BV), characterized by rash injuries on the teats and udder of lactating animals, and milkers hands and forearm in various regions and biomes in Brazil, mainly in southeast. Molecular and biological studies indicate the circulation in Brazil of two groups of VACV with distinct phenotypic and genetic characteristics. Due to the large number of reported cases of VB in recent years, the major impact of the disease to the country's economy, traditional in the production of milk and milk products, this study aims to evaluate the genetic and phenotypic diversity of Brazilian VACV isolates detected in both human and cattle specimens during 2005 to 2011 years in various regions of Brazil. Among of the 402 samples tested, 168 (41.8%) were positive after screening by PCR for viral VGF gene. Of these, 92 samples were selected for molecular characterization. Only three samples from the same outbreak, occurring in Serro region in 2011, showed the genetic signature of the group 2 of VACV-BR comprising mice-virulent strains such as GP1V, SAV, BAV and P1V, whereas the other samples showed the genetic profile group 1 of VACV-BR, comprising isolated as GP2V, PSTV, ARAV, CTGV and S2V. Biological and molecular data presented in this work show that co-circulation of different VACV lineages in Brazil, with a higher prevalence of group 1 samples. However, the reasons for this remain unknown. This was the first time a sample VACV-BR group 2 have been isolated from humans. The study of polymorphism between different isolates VACV opens the door to future studies of the genetic evolution of these isolates, its pathogenesis and even antiviral control.