Protecting zoo animals from a deadly pathogen: Encephalomyocarditis virus

What is it about?

In our PLOS Pathogens research article, we document a fatal outbreak of disease in a zoo caused by encephalomyocarditis virus or EMCV. While the unexpected death of animals in a zoo is always disheartening, in particular to the people who took care of the animals on a daily basis, one particularly shocking property often observed with EMCV infection is the speed of lethality by which the virus can kill animals. In some cases, an animal that appears normal behaviorally may simply ‘drop dead’ from EMCV infection a few hours later. Despite EMCV being a serious pathogen of concern for all facilities that house wild animals, it has largely been understudied in the United States, where zoo outbreaks are common. To address this, we studied a number of aspects of the ecology and evolution of the virus, including which rodent species it may be associated with during an outbreak and how well autogenous vaccines (i.e., a vaccine made from a viral isolate recovered from that particular zoo) protect animals from not only the homologous virus used to create the vaccine, but other more divergent EMCV strains that the zoo animals may encounter in nature.

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Photo by James Hammond on Unsplash

Photo by James Hammond on Unsplash

Why is it important?

The socio-economic costs of EMCV outbreaks in zoos can be significant due to the death of multiple animals, potential closure of exhibits, extensive rodent removal and abatement of nesting sites along with subsequent active rodent monitoring, in addition to the emotional toll on zoo personnel who took care of the deceased animals. In recent years, there have also been several EMCV outbreaks involving threatened or endangered species in managed care, thus putting additional strains on wildlife conservation efforts. Understandably, these outbreaks and the loss of unique and endangered wildlife, such as elephants as noted in our article, are a major concern to zoos and conservation programs worldwide. It is hoped that this work will serve as a foundation to better understand where the virus normally resides in nature, the factors that precipitate outbreaks, and how to best protect animals from disease.

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