Canine Adenovirus


Virus Characteristics

Effects on the Animal

Clinical Signs of Disease


Treatment and Prevention

Viruses of Dogs




  Virus Characteristics

Canine adenovirus-2 (CAV-2) is a member of the Adenoviridae virus family. It has been implicated as a cause of infectious diseases of the respiratory tract. Infectious tracheobronchitis (kennel cough) is an acute inflammation of the upper airways that can progress to fatal pneumonia in puppies, or to chronic bronchitis in older dogs. The disease is highly contagious and spreads quickly among dogs that are housed together (For example, kennels, veterinary clinics). CAV-2 is spread mainly via direct (nose-to-nose) and indirect contact with nasal secretions of infected dogs.

A 3-dimensional image of the adenovirus.

Effects on the Animal 

CAV-2 can be the primary virus involved in kennel cough, but infections involving canine parainfluenza virus and canine distemper virus may also be involved. In addition, agents such as Bordatella bronchiseptica can also serve as compounding factors in the formation of this disease. It is quite common that an infection will involve more than one of these agents. Stress and environmental extremes in ventilation, humidity and temperature can increase susceptibility to disease, and can also increase the severity of disease in an existing infection.

Several infectious agents lend to the appearence of Kennel Cough.

Clinical Signs 

Disease is first noted as a sudden harsh, dry cough, which can be productive or non-productive. Coughing is typically increased with excitement or exercise, and when pressure is applied to the neck with a collar. Affected dogs may experience gagging, retching and runny nose.

Dogs with non-complicated infections commonly do not show signs of a systemic illness, except for occasional partial anorexia. However, more serious respiratory complications can arise from the milder form of the disease. Secondary bacterial pneumonia can occur in young pups, as well as adult dogs with insufficient immune systems. Dogs with pre-existing ailments of the respiratory tract (For example, collapsed trachea, chronic bronchitis) may experience increased severity of these conditions. Such complicated infections may display clinical signs such as fever, pus in nasal discharge, depression, anorexia and productive coughing.

CAV-2 infections often cause coughing and retching.


The prognosis for recovery from uncomplicated infections is excellent. CAV-2 is typically self-limiting in healthy dogs and the infection resolves in approximately two weeks with appropriate treatment.

   Treatment and Prevention 

Prevention of disease involves minimizing exposure to the virus. Dogs that have recently been boarded in close proximity to other dogs should be isolated from other pups and dogs that have not been exposed. Kennel facilities should be adequately disinfected between uses. Keeping dogs in good health (For example,  proper nutrition and freedom from stress) will better enable them to respond to infection with CAV-2.

Dogs should also be immunized against CAV-2 via injection with a modified live virus vaccine. Puppies should receive their initial vaccinations when they are 6 to 8 weeks old. The vaccine should be administered 2 more times at 2 to 4 week intervals until the pups are 14 to 16 weeks old. Annual revaccination is recommended, but vaccinating at a lesser frequency may be acceptable for dogs that are at low risk of contacting the virus (Vaccination Program in Dogs).