Assessing the variability of Brazilian Vaccinia virus isolates from a horse exanthematic lesion: coinfection with distinct viruses

Abstract

During the last bovine vaccinia (BV) outbreaks, several Vaccinia virus (VACV) strains were isolated and characterised, revealing significant polymorphisms between strains, even within conserved genes. Although the epidemiology of VACV has been studied in BV outbreaks, there is little data about the circulation of the Brazilian VACV isolates. This study describes the genetic and biological characterisation of two VACV isolates, Pelotas 1 virus (P1V) and Pelotas 2 virus (P2V), which were obtained concomitantly from a horse affected by severe cutaneous disease. Despite being isolated from the same exanthematic clinical sample, P1V and P2V showed differences in their plaque phenotype and in one-step growth curves. Moreover, P1V and P2V presented distinct virulence profiles in a BALB/c mouse model, as observed with other Brazilian VACV isolates. Sequencing and phylogenetic analysis of four different genes demonstrated that the isolates are segregated in different VACV clusters. Our results raise interesting questions about the diversity of VACV isolates in Brazil.

Pseudovaríola e estomatite papular em bovinos no Estado de Rondônia, Brasil

“…Embora tenham sido identifi cados em propriedades diferentes, é curioso o fato de dois vírus distintos estarem associados com doença em rebanhos vizinhos no mesmo período, uma vez que os nove casos foram identifi cados entre fi nal de outubro e meados de novembro de 2012. A identifi cação concomitante de dois diferentes genótipos de poxvírus já foi relatada em rebanhos bovinos (TRINDADE et al, 2006) e equinos (CAMPOS et al, 2011) infectados pelo VACV, e em bovinos com lesões nos tetos decorrentes da coinfecção por VACV e ORFV (SANT 'ANA et al, 2013). Coinfecção também já foi relatada em ordenadores e bovinos com lesões causadas por VACV e PCPV (ABRAHÃO et al, 2010b).…”

“…Casos de coinfecções causadas por poxvírus de diferentes genótipos ou gêneros também já foram descritas em surtos de doença vesicular de bovinos (TRINDADE et al, 2006;. A origem e o signifi cado dessas coinfecções na patogenia das doenças ainda não estão esclarecidos, embora se acredite que a infecção associada com múltiplos vírus possa resultar em lesões mais severas e de aspecto infl amatório mais pronunciado (ABRAHÃO et al, 2010b;CAMPOS et al, 2011).…”

Experimental infection of horses with Vaccinia virus

“…Nonetheless, in 2008 a VACV outbreak, caused by two genetic and phenotypically divergent isolates was described in horses from Southern Brazil (BRUM et al, 2010;CAMPOS et al, 2011). The disease was characterized by ulcerative, scabby, and hemorrhagic lesion in the muzzle and mucocutaneous junction of mouth and nostrils (BRUM et al, 2010).…”

Guinea pigs experimentally infected with vaccinia virus replicate and shed, but do not transmit the virus

“…Two VACV strains (P1V and P2V), belonging from different genogroups, were isolated from the same sick animal (BRUM et al, 2010, CAMPOS et al, 2011. The origin of this outbreak is still under investigation yet some hypotheses have been considered and, progressively discarded.…”

“…Mice are also highly susceptible to VACV P1V e P2V (CAMPOS et al, 2012). Based on these studies, rabbits were proposed as a model for VACV pathogenesis (CARGNELUTTI et al, 2011 and mice have been used for preliminary phenotypic screening of VACV isolates (FERREIRA et al, 2008;CAMPOS et al, 2011).…”