Seven Things You Need to Know About Equine Influenza

Researchers have been hard at work studying this contagious respiratory disease.

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equine influenza
A healthy horse that has nose-to-nose contact with a sick horse might not show clinical signs, but still could be shedding virus because it has been infected. | Photo: iStock

Due to its potentially devastating economic impact, researchers have been hard at work studying this contagious respiratory disease

Equine influenza epidemics date as far back as 433 A.D. In more recent times, an 1872 outbreak in Canada and the northeastern United States brought all equine-based commerce, transportation, and services to a standstill—an estimated 80-99% of horses in the region were affected, with 1-2% dying. It only took 90 days for this epidemic to spread from Toronto, Canada, throughout the United States and as far south as Cuba. In an era when everything depended on transport via horse power, this had a staggering effect on daily life.

In 1987 in India, an outbreak involved the infection of 27,000 horses. In Australia in 2007, imported horses from Japan became the index cases of influenza that, due to biosecurity lapses, circulated from the quarantine station to infect 70,000 naive (never exposed or vaccinated) Australian horses, wreaking losses of a billion dollars in productivity and function.

You can see why researchers worldwide are so motivated to study this highly contagious disease and develop effective vaccines to protect the horse population

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Written by:

Nancy S. Loving, DVM, owns Loving Equine Clinic in Boulder, Colorado, and has a special interest in managing the care of sport horses. Her book, All Horse Systems Go, is a comprehensive veterinary care and conditioning resource in full color that covers all facets of horse care. She has also authored the books Go the Distance as a resource for endurance horse owners, Conformation and Performance, and First Aid for Horse and Rider in addition to many veterinary articles for both horse owner and professional audiences.

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