Many pet parents realize they can catch the flu during the chilly winter months. They wash their hands and take vaccinations to avoid getting sick. Unfortunately, most owners don’t know their dogs can also get dog flu. Canines can spread the flu, just like human beings do when they’re in close contact with one another.

In today’s Tipp City Veterinary Hospital blog, you’ll learn about canine influenza. Pet owners will find out about the illnesses symptom’s, effective treatments, and how to prevent the dog flu.

What is Canine Influenza (Dog Flu)?

Canine influenza (CI), or the dog flu, is a contagious viral infection that can harm dogs and cats. According to the American Veterinary Medical Association, the Type A influenza virus belongs to the Orthomyxoviridae family. There is no evidence of the disease can transmit between canines and humans.

Scientists have identified two strains of the influenza virus in the United States: H3N8 and H3N2. The Influenza A(H3N2) viruses differ from the seasonal influenza A(H3N2) ones that spread in people.

Influenza viruses mutate and give rise to new species that infect dogs. Both strains in America can be traced back to ones that have affected other species.

Canine influenza virus isn’t widespread in the American dog population. Many pets haven’t come in contact with the virus. Unfortunately, almost 80 percent of dogs exposed to canine influenza develop the illness. The mortality rate is less than 10 percent, and occur in pets with the most harmful forms of the disease. The worst cases have contracted pneumonia. There are no recorded fatalities of cats that developed canine influenza.

Where Did Canine Influenza Cases Originate?

Both H3N8 and H3N2 have two separate origins according to the U.S. Centers for Disease Control.

Canine H3N8 Influenza – In 2004, scientists first discovered the canine influenza H3N8 virus in Florida racing greyhounds. H3N8 was called equine influenza since it primarily infected horses. Researchers believed the virus adapted and jumped species from equines to canines. The virus now causes illness in dogs. It spreads among animals housed in kennels and shelters. This contagious virus has become a canine-specific illness.

After its identification, veterinarians said it was an emerging pathogen in the dog population in 2005. Today, scientists have detected H3N8 in most dogs within the United States and the District of Columbia.

Canine H3N2 Influenza – This virus originated in birds, then spread to dogs. Biologists discovered the Canine Influenza A H3N2 virus in South Korea around 2007. This contagious disease spread to dogs in Thailand, China, and Canada. The U.S. Centers for Disease Control identified the first United States H3N2 canine virus cases in April 2015. The federal agency located genetically identical versions of Asian H3N2 strains in American dogs. They’ve reported cases of H3N2 in 30 states. Infected canines have transmitted to the influenza virus to uninfected cats.

How Do Dogs Transmit Canine Influenza?

Dogs transmit the flu virus when they cough, bark, or sneezes that spray droplets or virus-containing aerosols that travel 20 feet away. It also spreads among canines who are in close contact with other infected dogs. These areas include kennels, shared food and water bowls, collars, and leashes. Other dogs transmit the virus when they come into contact with another canine’s nose when greeting them.

The H3N8 virus can stay alive on surfaces and infect other canines for up to 48 hours. Pet owners should use the following protocols to prevent the spread of infection between pets.

  • H3N2 CIV can remain in the environment for 12 to 24 hours. Pet owners can kill the virus using disinfectants or hand washing with soap and water.
  • Pet owners should disinfect any objects infected dogs have touched. Cleaning items will prevent exposing other canines to the virus.
  • People should wash their hands and clean all clothing if they come in contact with infected animals to lower transmission risks.

Can Dogs with the Flu Infect People?

Canine influenza viruses pose a low threat of transmission to people. So far, there is no evidence that the disease can transfer from dogs to people. There are no reported cases of canine influenza infections from dogs to human beings in the U.S. or internationally.

Influenza viruses rapidly change. In the future, the virus could infect people and spread. The World Health Organization uses a global surveillance system to detect human infections from influenza A viruses of animal origin (like the Avian or Swine Flu).

Incubation Period of the Canine Influenza

The H3N8 virus has an incubation period of one to five days. Your dog will show signs that it has contracted the virus between two and eight days after they’re infected. Most canines with H3N8 remain contagious for ten days after exposure.

Canines infected with H3N2 are contagious for up to 3 to 4 weeks (26 days) longer than other canine respiratory pathogens.

Dogs are most contagious during the incubation period. They can transmit the virus even if they don’t show clinical signs of illness. Pets with no symptoms can still shed the virus.

Tests for Dog Flu

Bring your pet to Tipp City Veterinary Hospital if you suspect they have the flu. Most dogs with canine influenza will have the following symptoms. They include:

  • Runny Eyes
  • Coughing (moist and dry)
  • Sneezing
  • Fever
  • Eye Discharge
  • Lethargy
  • Reduced Appetite
  • Nasal Discharge
  • Difficulty Breathing

About 20 – 25 percent of dogs infected with canine influenza are asymptomatic.

Canine flu symptoms resemble Kennel Cough and other respiratory illnesses in dogs. Veterinarians can’t diagnose the disease with clinical signs (coughing, sneezing, and nasal discharge). They must use a test to confirm the diagnosis.

PCR is the most accurate diagnostic test available. A staff member will swab the back of your dog’s nasal cavity and caudal pharynx to perform the PCR.


Most veterinarians will provide supportive care for canine influenza patients. This treatment will help dogs’ bodies mount an immune response to the illness. Many pets recover from dog flu within two to three weeks.

Secondary bacterial infections can occur with infected dogs. The illness can trigger other health issues including pneumonia, dehydration. Canines with secondary medical conditions like pulmonary disease, immunosuppression, and tracheal collapse may experience complications.

The majority of pets can receive outpatient care. Infected dogs should be isolated from other household pets for four weeks. Pet owners should bring their pet back to the vet if their canine stops eating, stays lethargic, or develops other clinical signs.

Treatments include the following:

  • Antimicrobials – These drugs will treat any suspected secondary bacterial infections in pets. Most antibiotic treatments are broad-spectrum such as doxycycline or Clavamox.
  • Nonsteroidal anti-inflammatory drugs – These medications can reduce fever and inflammation.
  • Fluids – The liquids will maintain hydration and correct dehydration.
  • Cough suppressants – This medication can stop your dog from coughing.

Prevention and Controlling the Spread

Canine influenza can persist in the environment for two days. It is viable on hands and clothing or 24 hours. Disinfectants easily kill the virus in boarding, veterinarian office, and shelters. These include benzalkonium chloride, aldehydes, potassium peroxymonosulfate, phenols and bleach solutions (1:30 dilution).

Owners should establish disinfection protocols to prevent transmission. Pet owners should clean their hands with soap and water in the following situations:

  • Upon arriving at home
  • Before handling each pet
  • After coming into contact with a pet’s saliva, urine, feces or blood
  • After cleaning a dog’s crate
  • Before eating meals, taking breaks, or leaving home
  • Before and after using the restroom

You should isolate all dogs showing clinical signs of influenza. They should not be brought to training classes, shows, events, daycare, or boarding facilities until they’ve healed.

Vaccinations for Canine Influenza

There are effective canine vaccines available for both the H3N8 and H3N2 canine flu strains. Vaccines aren’t right for every canine. Most veterinarians regard the influenza virus as a “lifestyle vaccine.” These vaccinations can prevent your pet from developing the flu and other complications. Whether your pet needs one or not depends on the following situations.

  • Owners don’t need to vaccinate their dogs if they don’t leave home or interact with others.
  • Many kennels require vaccinations before they’ll accept your dog. Even if the facility doesn’t enforce this requirement, your pet should still be vaccinated. Infected animals in confined areas can rapidly spread the virus to uninfected ones.
  • Get your dog vaccinated if you live in a city with high flu rates.
  • Your pet should receive a vaccination if it travels, goes to parks, or attends shows.
  • A dog or cat has secondary health conditions.

About Tipp City Veterinary Hospital

Stop by Tipp City Veterinary Hospital if you suspect your pet has contracted canine influenza. Contact us today to schedule an appointment with one of our veterinarians.