From lesions to viral clones: biological and molecular diversity amongst autochthonous Brazilian vaccinia virus.

Graziele Oliveira,Giliane Trindade,José Diomedes Neto,Rafael Calixto,Jonas Albarnaz,Ana Andrade,Cairo Oliveira,Jônatas Abrahão,Gabriel Almeida,Paulo Ferreira,Erna Kroon,Maurício Lima,Felipe Assis

doi:10.3390/v7031218

Abstract

Vaccinia virus (VACV) has had an important role for humanity because of its use during the smallpox eradication campaign. VACV is the etiologic agent of the bovine vaccinia (BV), an emerging zoonosis that has been associated with economic, social, veterinary and public health problems, mainly in Brazil and India. 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 at least two groups based on genetic and biological diversity: group 1 (G1) and group 2 (G2). In this study, we went to the field and investigated VACV clonal diversity directly from exanthemous lesions, during BV outbreaks. Our results demonstrate that the G1 VACV-BR were more frequently isolated. Furthermore, we were able to co-detect the two variants (G1 and G2) in the same sample. Molecular and biological analysis corroborated previous reports and confirmed the co-circulation of two VACV-BR lineages. The detected G2 clones presented exclusive genetic and biological markers, distinct to reference isolates, including VACV-Western Reserve. Two clones presented a mosaic profile, with both G1 and G2 features based on the molecular analysis of A56R, A26L and C23L genes. Indeed, some SNPs and INDELs in A56R nucleotide sequences were observed among clones of the same virus population, maybe as a result of an increased mutation rate in a mixed population. These results provide information about the diversity profile in VACV populations, highlighting its importance to VACV evolution and maintenance in the environment.

Highlights

Vaccinia virus (VACV) has had an important role in human history due to its use as a vaccine during the smallpox vaccination campaign, resulting in the eradication of this deadly disease in 1980 [1]
Three clones isolated from the VACV-BABV (BABV-Clone 2, BABV-Clone 3 and BABV-Clone 4) showed a large-plaque profile, while two other clones (BABV-Clone 1 and BAB-Clone 5) presented a small-plaque profile; and the VACV-GOBV showed a single clone (GOBV-Clone 2) with a large-plaque profile and four clones (GOBV-Clone 1, GOBV-Clone 3, GOBV-Clone 4 and GOBV-Clone 5) with the small-plaque profile
Bovine vaccinia outbreaks have been increasingly reported in Brazil since 1999 causing economic, social, veterinary and public health problems [11]

Summary

Introduction

Vaccinia virus (VACV) has had an important role in human history due to its use as a vaccine during the smallpox vaccination campaign, resulting in the eradication of this deadly disease in 1980 [1]. Following Smallpox eradication, other zoonotic orthopoxviruses (OPV) have emerged worldwide, such as Cowpox virus (CPXV), in Europe, Monkeypox virus (MPXV), endemic in many African countries and recently introduced in the USA, and VACV, endemic in Brazil and India [5,6,7,8,9,10,11,12,13]. The lesions occur primarily on milkers’ hands and arms. Other symptoms, such as fever, myalgia, headache, arthralgia and lymphadenopathy are frequently reported [11,16]. Reports have suggested a possible human-to-human transmission of VACV [16,17,18]

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