Update on Equine and Canine Influenza

The best way to protect your horses and dogs from influenza virus is to vaccinate at-risk animals, practice good hygiene, and isolate infected animals, according to Tara C. Anderson, DVM, MPH, a PhD candidate at the University of Florida.

Anderson and her UF colleague, E. Paul J. Gibbs, BVSc, PhD, Fellow RCVS, wrote a review of equine and canine influenza (EIV and CIV) to "summarize influenza viruses that affect horses and dogs and highlight the importance of monitoring our companion animals for infectious diseases such as influenza."

Even though there is no evidence that people can acquire either virus from their pets, influenza viruses have shown they can mutate rapidly and jump species. Therefore, they should be included in surveillance and monitoring programs, Anderson reasoned.

In the United States EIV jumped to dogs and mutated to create a new species-specific disease--canine influenza virus. Other countries also have reported incidences of EIV virus jumping from horses to dogs; therefore it's a good idea to separate dogs and horses if there is an EIV outbreak on the farm, she warned.

So far there have been no reports of horses getting CIV. "Experimental work has shown that horses are susceptible to CIV; however, there have been no reported transmissions of CIV to any other species, including horses."

As for EIV, outbreaks can be challenging for horse owners to manage. Influenza viruses are difficult to contain because animals transmit the virus to others before they show signs of being sick, and many animals do not develop clinical signs but still shed virus.

"Health exams and quarantines are important for disease prevention; however, once the pathogen is introduced into a horse population, it is highly contagious and the severity of the outbreak will depend on many factors, including the prior immunity of the population," she said, which is why vaccination is important.

The study, "Equine and canine influenza: a review of current events" was published online ahead of print in the April Animal Health Research Reviews.

The abstract is available on PubMed.

About the Author

Marie Rosenthal, MS

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