Many area dog clinics are tightening their protocols after doctors confirmed a fourth case of canine influenza, or dog flu, in Knoxville.

The University of Tennessee College of Veterinary Medicine’s virology lab said one of the infected dogs developed severe pneumonia and had to be euthanized.

West Bearden Veterinary Hospital is one of several vet clinics that will soon require flu vaccinations for incoming dogs prior to boarding. The facility will officially implement the change in September.

PREVIOUS: 2 new cases of dog flu confirmed in Knoxville area

"It used to be very rare for a clinic to require influenza [vaccinations], but now we and other clinics are now requiring that," said the animal hospital’s assistant manager Sierra Slautterback.

Slautterback said between the company’s two clinic locations, staff have administered at least 30 flu vaccines within the past week – a stark contrast from its previous average of only one every three months prior to the outbreak.

West Bearden is just one of several animal hospitals and clinics now requiring flu vaccinations for incoming dogs prior to boarding.

At Concord Veterinary Hospital in West Knoxville, which also now requires the vaccine for dog boarding, staff have administered at least 150 vaccines in the last week and ordered another 250 to prepare for the upcoming travel season.

UT's Veterinary School said, unlike the first three cases, the latest one has no apparent connection to a dog show in Georgia.

“Because of that, we’re more concerned about it getting into the general pet population,” said UT Veterinary Virologist Dr. Melissa Kennedy. She added, “Still, the majority of pet dogs are at low risk for exposure to this virus.”

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After the first two cases, Kennedy only recommended the vaccination for show dogs and dogs who stayed in boarding facilities. Now, she is recommending vaccinations for all social dogs that go to dog parks, kennels or groomers.

Kennedy said it’s easy to confuse dog flu with a simple kennel cough. Unlike kennel cough, dogs with dog flu often run a fever that can cause them to appear lethargic and even stop eating.

She recommends owners contact their veterinarian if they suspect their dog might be displaying those symptoms.

The virus is generally mild, similar to the flu in humans. In rare cases, it can become deadly with puppies, older dogs or dogs with immune deficiencies.