Canine Influenza


Canine influenza (CI), or dog flu, is a highly contagious viral infection affecting dogs as well as cats. Influenza infections belong to the household Orthomyxoviridae. Canine influenza is a Type A influenza infection and is even more identified based upon the composition of two specific proteins in the lipid external layer of the capsid: hemagglutinin (HA) and neuraminidase (NA). At present, two strains of canine influenza infection have actually been recognized in the United States: H3N8 and H3N2.

Influenza viruses are able to quickly change and give rise to brand-new pressures that can infect various species. Both stress of canine influenza recognized in the U.S. can be traced to influenza strains understood to infect types besides dogs. At some point, these viruses got the capability to contaminate dogs and be transmitted from dog to dog.

Canine H3N8 influenza was first determined in Florida in 2004 in racing greyhounds. It is thought this stress developed from an equine H3N8 influenza pressure that jumped from horses to dogs. Because being discovered in 2004, canine H3N8 influenza has been recognized in dogs in a lot of U.S. states and the District of Columbia.

Canine H3N2 influenza was first recognized in the United States in March 2015 following a break out of breathing illness in dogs in the Chicago area. Prior to this, reports of canine H3N2 influenza virus were limited to South Korea, China and Thailand. It was initially identified in dogs in Asia in 2006-2007 and most likely arose through the direct transfer of a bird influenza infection– potentially from amongst infections circulating in live bird markets– to dogs.

Following the initial medical diagnosis in Chicago, extra cases of canine H3N2 influenza were reported in a number of states. In early 2016, a group of shelter cats in Indiana were diagnosed with H3N2 canine influenza. It is believed the virus was transferred to them from contaminated dogs.

In May 2017, canine H3N2 influenza was identified in dogs in Florida, Georgia, North Carolina, South Carolina, Texas, Kentucky, Tennessee, Missouri, Louisiana, and Illinois. This was the same stress of H3N2 associated with the 2015 outbreak in Chicago.

There is no evidence that either stress of canine influenza (H3N8 or H3N2) can infect humans.

What Causes Canine Flu?

The virus that causes dog flu, Influenza Type A (H3N8), was first determined in Florida in 2004. It mainly infects the respiratory system and is exceptionally contagious. A vaccine was given full license by the United States Department of Agriculture in 2009 (Nobivac ® Canine Flu H3N8). Some dogs can be exposed to the infection and fight off infection without showing clinical signs.

Canine Flu Symptoms

Dogs that are infected with the canine influenza virus might develop two various syndromes:

  • Mild. These dogs will have a cough that is typically wet and can have nasal discharge. Sometimes, it will be more of a dry cough. Most of the times, the symptoms will last 10 to 30 days and generally will disappear on its own.
  • Severe. Generally, these dogs have a high fever (above 104 degrees Fahrenheit) and develop signs very quickly. Pneumonia, particularly hemorrhagic pneumonia, can establish. The influenza virus affects the capillaries in the lungs, so the dog may spend blood and have difficulty breathing if there is bleeding into the alveoli (air sacs). Patients might also be infected with bacterial pneumonia, which can further complicate the circumstance.

General signs of these syndromes include:

  • coughing
  • sneezing
  • anorexia
  • fever
  • despair

Red and/or runny eyes and runny nose might be seen in some dogs. In many cases, there is a history of contact with other dogs that carried the infection.


Besides a physical, the vet will want to perform a complete blood count and clinical chemistry on the dog. Usually, boosts are seen in the white blood cells, specifically the neutrophils, a white blood cell that is damaging to microbes. X-rays (radiographs) can be taken of the dog’s lungs to identify the kind of pneumonia.

Another diagnostic tool called a bronchoscope can be used to see the trachea and larger bronchi. Cell samples can also be gathered by performing a bronchial wash or a bronchoalveolar lavage. These samples will usually have big amounts of neutrophils and might consist of bacteria.

Finding the virus itself is extremely tough and is normally not advised. There is a blood (serological) test that can support a canine influenza medical diagnosis. Most of the times, a blood sample is taken after initial symptoms establish and then again 2 to 3 weeks later on.

What to Do When Your Dog Has the Flu?

The mild type is generally treated with cough suppressants. Antibiotics might be used if there is a secondary bacterial infection. Rest and isolation from other dogs is likewise essential.

The severe type has to be dealt with strongly with a broad spectrum of antibiotics, fluids and other basic support treatments. Hospitalization and isolation are needed until the dog is stable.

Living and Management

A vaccine for the canine flu is currently readily available, though it needs to just be thought about after talking with your vet. In addition, there are other breathing conditions that can be immunized against, specifically Bordetella bronchiseptica, the bacteria responsible for what is typically called “kennel cough.”

Any dog that is presumed to have canine influenza should be isolated from other dogs. Those dogs with the mild type of the infection generally recuperate on their own. Dog influenza is not a contagion problem for human beings or other species.


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