Zoonotic Vaccinia Virus Outbreaks in Brazil

Abstract

The vaccinia virus (VACV) was used as a live vaccine during the WHO-led smallpox eradication campaign in the second half of the 20th century. The program culminated with the obliteration of the disease, one of the most important achievements in modern medicine. Interestingly, one of the key factors in the successful vaccination campaign – the VACV itself – is poorly understood in relation to its natural reservoirs, evolutionary history and origins, being frequently considered extinct as a naturally occurring virus. Nevertheless, orthopoxviruses other than variola virus have been known to circulate in Brazil since the early 1960s. More specifically, VACV has been associated with naturally acquired infections in humans, cattle and possibly other reservoirs since 1999, when bovine vaccinia outbreaks started to be consistently described year after year. In this article, we list and discuss the most important VACV outbreaks that have occurred in Brazil in the last 20 years. Phylogenetic issues are considered, as the latest studies point to large genetic variance among isolates. Clinical and epidemiological data, both published and new, are presented.

Keywords:

• bovine vaccinia
• orthopoxvirus
• phylogenetic analysis
• vaccinia virus
• zoonosis

Acknowledgements

The authors would like to thank all the students involved in the many outbreak studies over the years. Special thanks to Tânia Apolinário for critical reading of the manuscript and support.

Financial & competing interests disclosure

FG da Fonseca, EG Kroon, ML Nogueira and G de Souza Trindade are CNPq fellowship recipients. Parts of the work described in this article were supported by a CNPq grant, process number 473205/2009-2. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Additional information

Funding

FG da Fonseca, EG Kroon, ML Nogueira and G de Souza Trindade are CNPq fellowship recipients. Parts of the work described in this article were supported by a CNPq grant, process number 473205/2009-2. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.