Equine influenza is easily spread among horses, but there are ways to decrease exposure and reduce the severity of the disease.

EQUUS “Farm Calls” is brought to you in 2022 by Farnam—Your Partner in Horse Care.

“Equine influenza is like human flu in that it is caused by a virus that produces respiratory illness,” said Dr. Tom Chambers, a professor at the University of Kentucky’s Gluck Equine Research Center.

Chambers focuses his research on the study of infectious diseases and heads one of three global Equine Reference Laboratories for Equine Influenza under the aegis of the World Organization for Animal Health. He has been at the Gluck Center for nearly 32 years, having studied avian and human influenza viruses for 10 years before that, and has been in the forefront of equine influenza vaccine research.

Chambers said equine influenza clinical signs differ from horse to horse. One horse might get a 106-degree fever and the next horse doesn’t look sick, even though it is infected with the influenza virus. However, noted Chambers, just because the horse doesn’t look sick doesn’t mean it is not shedding influenza virus!

“The way the virus survives is to not make the horse do anything different,” said Chambers. That way the horse co-mingles with other animals and the virus continues to spread.

And spread it does! Rapidly!

One of the ways the influenza viruses are so efficient is that they are always changing their “appearance” to the host. That way the host’s immune system has a hard time building defenses against influenza virus.

Horse owners have learned those lessons about respiratory virus spread well in the last few years of the COVID-19 pandemic.

“Equine influenza is seldom fatal,” noted Chambers. Killing the host is not a great way to continue to spread a virus, so it is not in the virus’ best interest to kill everything it comes in contact with.

“There are [equine influenza] vaccines that are good, but they do not give life-long protection,” said Chambers.

Any horse is potentially at risk to contract equine influenza, but the risk is greater when horses mingle in social groups outside their usual environments. “The shipping process is stressful, and stress can let some viruses take hold,” said Chambers.

Horse owners should talk to their veterinarians about risk-based vaccination strategies for protecting their animals against equine influenza. Another way to protect horses is to practice good biosecurity.

“You can’t put masks on horses, but you can use social distancing, as in quarantine,” said Chambers.

He recommends that any horse coming to your property from another farm or area be quarantined for two weeks.

In this podcast Chambers talks about:

• What is equine influenza?
• Why is it important to horse owners?
• Horse owners have learned from COVID-19 that respiratory viruses “change” or “drift” with a “new strain” occurring, which is true of equine influenza. Explain that to us.
• What horses are at most risk?
• How can you best protect horses from equine influenza?
  • Vaccines
  • Management/biosecurity
• Testing is important, so let your vet swab your horse and submit it; what happens to those tests?
• Disinfecting against equine influenza
• What’s going on in your lab now?

EQUUS “Farm Calls” is a production of the Equine Network LLC.