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

Abstract

Orthopoxvirus (OPV) infections have been present in human life for hundreds of years. It is known that Variola virus (VARV) killed over 300 million people in the past; however, it had an end thanks to the physician Edward Jenner (who developed the first vaccine in history) and also thanks to a massive vaccination program in the 20th century all over the world. Although the first vaccine was created using the Cowpox virus (CPXV), it turned out later that the Vaccinia virus was the one used during the vaccination program. VACV is the etiological agent of bovine vaccinia (BV), a zoonotic disease that has emerged in Brazil and South America in the last 20 years. BV has a great impact on local dairy economies and is also a burden to public health. In this review, we described the main events related to VACV and BV emergence in Brazil and South America, the increase of related scientific studies, and the issues that science, human and animal medicine are going to face if we do not be on guard to this virus and its disease.

Keywords: Vaccinia virus; bovine vaccinia; laboratory diagnosis; neglected disease; public health; zoonosis.

Figure 1

Characterization of vaccinia virus circulation in the South American continent. (A) Map of South America indicating the countries where VACV has been detected or suggested to be circulating. The countries in gray color have not recorded VACV detection or suggestion so far. The blue gradient in the left highlights the first records of VACV in Brazil starting in 1999 to the last one in 2014, in Colombia. (B) Map of Brazil indicating the States where VACV has been detected or suggested to be circulating. The states in gray color have not recorded VACV detection or suggestion so far. The blue gradient in the right highlights the States from the lowest to the highest index of records reported by scientific publications. Acre (AC), Maranhão (MA), Mato Grosso (MT), Pernambuco (PE), Rondônia (RO), Tocantins (TO), and the Federal District (DF) present only one record each. On the other hand, Minas Gerais (MG) is the state with the highest number of VACV cases (110 records). The pink circles indicate the States of Brazil where there are certified laboratories for the diagnosis of Poxvirus diseases. This map was made using the Free and Open Source QGIS program based on free shapefiles by Instituto Brasileiro de Geografia e Estatística (IBGE) available at https://www.ibge.gov.br/geociencias/downloads-geociencias.html (accessed on 16 October 2020).

Figure 2

(A) Distribution of published scientific papers about Vaccinia virus and/or Bovine Vaccinia, Flavivirus, Alphavirus and Arboviruses during 2000–2020 in Brazil. We included a total of 3.511 publications identified by conducting electronic searches in PubMed platform, available at https://pubmed.ncbi.nlm.nih.gov/ (accessed on 15 March 2021). Published studies were identified using the keywords Vaccinia virus, Bovine Vaccinia, and Brazil (n = 281); Flavivirus and Brazil (n = 2.184); Alphavirus and Brazil (n = 243); and Arboviruses and Brazil (n = 803). An average of 13.4 VACV publications per year were identified. (B) Analysis between the numbers of published papers in Brazil (according to the theme of interest) and the summary of scientific research investments over the past twenty years. Although the decrease in publications of BR-VACV is related to the reduction in funding for its research, the same is not valid for the research related to arboviruses.

Figure 3

A vertical timeline of the main events regarding the Vaccinia virus occurrence dairy products and cattle in Brazil during 2000–2020.