CDV infects an animal through aerosol inoculation (breathing) or through ingestion. The virus contacts epithelium of the respiratory tract where it is picked up by macrophages. The virus is carried to local lymphatics – tonsils and bronchial lymph nodes. Virus numbers increase here as the virus divides. By about day 5, the virus makes its way to the spleen, lamina propria of the stomach, small intestine, mesenteric lymph nodes and the Kupffer cells of the liver.  This spread induces a profound immunosuppression in the animal.

Dependent upon the individuals ability to mount an immune response to the virus, several things can occur to the dog:

1) Those animals with adequate antibodies and that are able to mount a good immune response should have cleared the virus and should show no real apparent illness. These animals also have a very low prevalence of CNS illness

2) Dogs with intermediate or low levels of immune response will likely have viral spread to the epithelial tissues by about day 10. This is the time when shedding of the virus, which can be done from any body excretion, can occur. CNS infection is possible. These signs develop after the GI and respiratory signs have been expressed.   After, the dog can again recover, although his chances of doing so are now lower than in those animals with a better immune system.

Those dogs  that do not recover  can develop chronic neurological signs caused by demyelination. This dogs will usually die. Other dogs may appear to recover from the virus, which is misleading. The  virus will remain the brain, and after a period of time (often years), recurrent neurological problems will develop, including such signs as atazia and seizures.

The incubation period for the virus is between 6 and 10 days. Vaccination is highly recommended as prevention is the best cure.

Viral Characteristics
Clinical Signs
Transmission and Risk
Other Species
Treatment and Prognosis
Medical Dictionary