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The veterinary significance of emerging infectious diseases

Published: 9/10/2018

In this article from Clinician’s Brief, our official clinical practice journal, Dr. J. Scott Weese of the University of Guelph, Canada, takes the reader through the various paths and mechanisms that account for the appearance of new veterinary and human diseases...

Emerging infectious diseases pose a significant threat to humans and animals but are inherently unpredictable. Although historical trends and disease patterns can provide insight, determining which diseases are likely to emerge and the impact they will have on human and animal populations is an educated guess at best. Of additional concern is the estimate that 60% to 80% of emerging diseases are zoonotic,¹ which emphasizes the importance of veterinarians in the identification, prevention, and control of emerging infectious diseases.

An ecosystem approach to health considers disease occurrence to be at the intersection of the microbial agent, the host (human or animal), and the environment.¹ Any alterations in the agent, host, or environment can alter the risk for disease. Thus, new infectious disease threats can emerge from a variety of sources.

Emergence of New Pathogens

Emergence of new pathogens is uncommon but continues to occur. If highly transmissible, new pathogens can have profound effects, as the worldwide population would be immunologically naïve to the emerging pathogen. For example, the emergence of canine parvovirus in the 1970s² became a worldwide epidemic, with rapid international transmission and high morbidity and mortality rates.

Canine influenza is a more recent example of the threats posed by emerging pathogens. The emergence of equine-origin canine influenza H3N8 in the United States in the early 2000s3 demonstrated the potential impact of antigenic shift of influenza on the canine population. The more recent emergence of avian-origin canine influenza H3N2 caused—and continues to cause—widespread illness and disruption in parts of Asia, the United States, and Canada. 4,5

Zoonotic potential of emerging diseases requires sustained vigilance in a world of changing climate and increased travel worldwide.

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