Canine Adenovirus


What is Canine Adenovirus?

There are two types of canine adenovirus, type one (CAV-1) and type two (CAV-2). Canine adenovirus-1 causes infectious canine hepatitis, which is a viral infection of the liver. While canine adenovirus-2  is one of a few viruses that causes canine infectious tracheobronchitis, which is also known as kennel cough.


What are the symptoms of Canine Adenovirus?

Canine Adenovirus, type one (CAV-1)

Symptoms of this type of adenovirus can cause a brief illness with non-specific mild symptoms such as:

  • decreased appetite

  • lethargy

  • mild fever

Severe cases can result in liver disease. Symptoms of liver disease can include:

  • jaundice

  • vomiting

  • hepatic encephalopothy

  • abdominal pain

Some dogs with CAV-1 infection can develop cloudiness on one or both of their eyes, this is known as “blue eye”. Some severe cases can also develop bleeding disorders. Death can results from a severe case due to the bleeding disorder or severe liver disease progressing to liver failure.

Canine Adenovirus, type two (CAV-2)

Symptoms of this type of adenovirus can cause symptoms related to the respiratory system. Some dogs who have contracted the virus may not show any signs of infection, while other may show some or all of the following symptoms:

  • Low-grade fever

  • Nasal discharge

  • Lack of energy

  • Loss of appetite

  • A dry, hacking cough

  • Retching and gagging

  • Coughing up a white, foamy discharge

  • Conjunctivitis

How is Canine Adenovirus diagnosed?

Canine Adenovirus, type one (CAV-1)

If infectious canine hepatitis is suspected a complete blood and urine profile will be recommended to look for signs of infection and liver disease. Other laboratory tests may include coagulation tests to check for the clotting function and serology testing for antibodies to CAV-1. Tests may also be done to rule out canine parvovirus and canine distemper.

Diagnostic imaging such as x-rays or ultrasound may be needed to look for enlargement of the liver and fluid in the abdominal cavity.

A liver biopsy may also need to be performed to make a conclusive diagnosis.


Canine Adenovirus, type two (CAV-2)

Specific diagnosis of CAV-2 is usually not necessary.  The dog will usually be diagnosed as having kennel cough, but whether it was caused by CAV-2 or another respiratory virus is usually not investigated. Diagnosis is usually based on the dog’s medical history, clinical signs, vaccination history and physical exam.

How is Canine Adenovirus treated and prevented?

Adenoviruses are spread directly from dog to dog through infected respiratory secretions or by contact with contaminated feces or urine. Infected dogs (with either form of the virus) should be separated from other dogs in the household and kept away from kennels, off leash parks and other areas frequented by dogs until the infection has run its course.

Canine Adenovirus, type one (CAV-1)

Since it is a virus, treatment is centered on supportive care to decrease the severity of the symptoms. Most dogs recover with outpatient treatment if the attack is mild, but more severe cases may need hospitalization. Fluid therapy may be recommended in the form of subcutaneous fluids for a mild infection. IV fluid therapy may be necessary for dogs suffering from something more severe. Antibiotics are given to decrease the risk of bacterial infection which can result from a weakened immune system. These can be administered orally or by injection if the dog is hospitalized. Supplements that promote liver cell regeneration may also support recovery from canine infectious hepatitis. In extreme severe cases, blood transfusions may be necessary.

Lesions and tissue damage sometimes remain visible on the interior organs of dogs who have survived severe forms of the disease. During the course of the disease lesions are also commonly seen on the eye (“blue eye”). These eye lesions usually remain after recovery, making  your dog’s eyes more sensitive to bright for the rest of their lives.


Canine Adenovirus, type two (CAV-2)

Many canine infectious respiratory diseases, including the one caused by CAV-2 are usually self limiting diseases. They will run their course within a two week period. If the infection is more severe, cough suppressants may be prescribed. Chronic cases may require antibiotics if a secondary infection has had opportunity to set in. Supplementation with probiotics or other immune system support product may be recommended to help their immune system. Using a humidifier or placing your dog in the bathroom while you shower can help with congestion and discomfort.

Dogs suffering from canine infectious tracheobronchitis should also be kept away from respiratory irritants such as cigarette smoke, strong fragrances, camp fire smoke etc.


Vaccination is available against canine adenovirus, it is part of the DA2PP core vaccine given to dogs (the “A” in the vaccine name stands for adenovirus). Since canine adenovirus-2 is closely related to canine adenovirus-1, the modified live canine adenovirus-2 is used in the vaccine will provide protection against both canine infectious tracheobronchitis and canine infectious hepatitis.