Abstract
Vaccinia virus naturally circulates in Brazil and is the causative agent of a zoonotic disease known as bovine vaccinia (BV). We retrospectively evaluated two populations from the Amazon and Southeast Regions. BV outbreaks had not been reported in these regions before sample collection. Neutralising antibodies were found in 13 individuals (n = 132) with titres ranging from 100 ≥ 6,400 neutralising units/mL. Univariate analysis identified age and vaccination as statistically significant risk factors in individuals from the Southeast Region. The absence of detectable antibodies in vaccinated individuals raises questions about the protection of smallpox vaccine years after vaccination and reinforces the need for surveillance of Orthopoxvirus in Brazilian populations without evidence of previous outbreaks.
Highlights
Thirty-four years ago, the world celebrated the eradication of smallpox, a lethal disease caused by Variola virus infection
Vaccinia virus (VACV), a species belonging to the Orthopoxvirus (OPV) genus that demonstrates serological cross-reactivity with other OPV species, was used as the vaccine antigen during the World Health Organization (WHO) campaign
bovine vaccinia (BV) outbreaks associated with vaccine strains were reported during the smallpox eradication campaigns in Latin America and Asia (Fenner et al 1988), these notifications ceased after vaccination suspension, with only a few cases reported in the 1980’s in Southeast Brazil related to contact with cows during milking (Silva et al 1986)
Summary
Thirty-four years ago, the world celebrated the eradication of smallpox, a lethal disease caused by Variola virus infection. VACV is the cause of a zoonotic disease known as bovine vaccinia (BV) and can be transmitted to humans by direct contact with infected animals during milking, resulting in lesions on the hands and arms
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