One More Piece in the VACV Ecological Puzzle: Could Peridomestic Rodents Be the Link between Wildlife and Bovine Vaccinia Outbreaks in Brazil?

Abstract

BackgroundDespite the fact that smallpox eradication was declared by the World Health Organization (WHO) in 1980, other poxviruses have emerged and re-emerged, with significant public health and economic impacts. Vaccinia virus (VACV), a poxvirus used during the WHO smallpox vaccination campaign, has been involved in zoonotic infections in Brazilian rural areas (Bovine Vaccinia outbreaks – BV), affecting dairy cattle and milkers. Little is known about VACV's natural hosts and its epidemiological and ecological characteristics. Although VACV was isolated and/or serologically detected in Brazilian wild animals, the link between wildlife and farms has not yet been elucidated.Methodology/Principal FindingsIn this study, we describe for the first time, to our knowledge, the isolation of a VACV (Mariana virus - MARV) from a mouse during a BV outbreak. Genetic data, in association with biological assays, showed that this isolate was the same etiological agent causing exanthematic lesions observed in the cattle and human inhabitants of a particular BV-affected area. Phylogenetic analysis grouped MARV with other VACV isolated during BV outbreaks.Conclusion/SignificanceThese data provide new biological and epidemiological information on VACV and lead to an interesting question: could peridomestic rodents be the link between wildlife and BV outbreaks?

Emergence and Reemergence of Vaccinia-Like Viruses: Global Scenario and Perspectives

“…monkeypox, buffalopox and bovine vaccinia infections [43]. In addition to a close variant of VACV called as buffalopox virus (BPXV) circulating among buffaloes, cows and human in India, there were many reports of emergence of human and animal pox infections in other parts of the world namely VACV like agents called Aracatuba virus (ARAV) and Cantagalo virus (CTGV) in cattle, humans [9,39] and wild rodents [1] have been reported in Brazil. There has been increase in the incidence of vaccine like virus infections in some parts of the world affecting not only animals but also humans.…”

Experimental infection of horses with Vaccinia virus

“…Vaccinia virus (VACV) belongs to family Poxviridae, genus Orthopoxvirus, and is associated with exanthematic and vesicular disease mainly in cattle, but also in man and, possibly in wild and peridomestic rodents (TRINDADE et al, 2007;ABRAHÃO et al, 2009;BORGES et al, 2013;PERES et al, 2013). Natural infection by VACV in horses was reported in Brazil, yet it seems to be a rare event (BRUM et al, 2010;MATOS et al, 2013).…”

“…The natural cycle of VACV infection is not completely known, yet the participation of wild/peridomestic rodents as reservoirs had been suggested (ABRAHÃO et al, 2009;BORGES et al, 2013;PERES et al, 2013). If this were the case, peridomestic rodents could transmit the virus to farm animals and then to man (ABRAHÃO et al, 2009).…”

“…If this were the case, peridomestic rodents could transmit the virus to farm animals and then to man (ABRAHÃO et al, 2009).…”

Vaccinia Virus: It’s Use in Smallpox Vaccine and Epidemiology

“…After ends of world vaccination campaign in Brazil in 1980, zoonotic Vaccinia outbreaks has been recorded in several regions of the country [4][5][6][7][8][9][10][11][12]. It is believed that the VACV used in the word vaccination campaign in Brazil from 1960 to 1970 was involved in the re-emergence of the disease [13].…”