Serological Evidence of Orthopoxvirus Circulation Among Equids, Southeast Brazil

Abstract

Since 1999 Vaccinia virus (VACV) outbreaks involving bovines and humans have been reported in Brazil; this zoonosis is known as Bovine Vaccinia (BV) and is mainly an occupational disease of milkers. It was only in 2008 (and then again in 2011 and 2014) however, that VACV was found causing natural infections in Brazilian equids. These reports involved only equids, no infected humans or bovines were identified, and the sources of infections remain unknown up to date. The peculiarities of Equine Vaccinia outbreaks (e.g., absence of human infection), the frequently shared environments, and fomites by equids and bovines in Brazilian farms and the remaining gaps in BV epidemiology incited a question over OPV serological status of equids in Brazil. For this report, sera from 621 equids - representing different species, ages, sexes and locations of origin within Minas Gerais State, southeast Brazil – were examined for the presence of anti-Orthopoxvirus (OPV) antibodies. Only 74 of these were sampled during an Equine Vaccinia outbreak, meaning some of these specific animals presented typical lesions of OPV infections. The majority of sera, however, were sampled from animals without typical signs of OPV infection and during the absence of reported Bovine or Equine Vaccinia outbreaks. Results suggest the circulation of VACV among equids of southeast Brazil even prior to the time of the first VACV outbreak in 2008. There is a correlation of OPVs outbreaks among bovines and equids although many gaps remain to our understanding of its nature. The data obtained may even be carefully associated to recent discussion over OPVs history. Moreover, data is available to improve the knowledge and instigate new researches regarding OPVs circulation in Brazil and worldwide.

Twenty Years after Bovine Vaccinia in Brazil: Where We Are and Where Are We Going?

“…Furthermore, the presence of domestic felids on a property was significantly associated with diminished odds of a cow having OPV-neutralizing antibodies. Another study also conducted in Minas Gerais State revealed a seroprevalence of neutralizing antibodies against OPV in 20.6% was also described in equids, raising questions about the role of equids in the VACV epidemiological chain, as well as unrecognized infections and silent circulation [ 51 ].…”

Monkeypox 2022 outbreak in non-endemic countries: Open questions relevant for public health, nonpharmacological intervention and literature review

“…As a matter of fact, the evidence of intense animal circulation of OPXVs in rural areas of Brazil in the absence of recognized outbreaks was corroborated by subsequent serological studies in humans, dairy cattle, horses, and wild animals ( Costa et al., 2016 ; Borges et al., 2017 ; Miranda et al., 2017 ; Rehfeld et al., 2017 ; Borges et al., 2018 ), and by outbreak reports in domestic buffalo calves from various Brazilian areas, caused mainly by the brazilian VACV strain, named Pernambuco (VACV-PE) ( Franco-Luiz et al., 2016 ; Costa et al., 2016 ; Lima et al., 2018 ).…”

Educational Approach to Prevent the Burden of Vaccinia Virus Infections in a Bovine Vaccinia Endemic Area in Brazil

“…BV is endemic in Serro region and different studies have already reported several outbreaks since 2005 [ 2 , 24 , 25 , 26 ]. Furthermore, other studies conducted in the absence of outbreaks have also reported VACV infections in humans, dairy cattle, horses, and wild animals through serological assays [ 23 , 32 , 37 , 38 , 39 ].…”