As is evidenced by the clinical signs, dogs are extrememly variable in terms of presenting signs, and in terms of when these signs  appear This makes definative diagnosis a challenge and can be frustrating for the veterinarian.  The following signals should make you suspect you have a distemper case:

1) Poor previous vaccination history. Puppies should be vaccinated between 6 and 8 weeks of age, and then given two more boosters at 12 and 16 weeks. If this has not been done, the risk of developing distemper is substantially higher in the puppy.

2) History of exposure. The virus is very contagious, so exposure to other dogs or their environment increases the risk of your dog getting distemper.

3) Physical exam findings. Again these can be variable dependent on a number of factors such as age, immune status, overall health of the animal, etc. In some cases signs do not appear until late in the disease, whereas other animals may show signs after only been infected for about 5 days. Check out clinical signs for more information.

4) Postitive identification based on blood samples or necropsy results (histologic lesions or immunoflurescent assay for viral antigen in tissues)

Distemper is often confused with other systemic infections including:

- leptospirosis
- infectious canine hepatitis
- Rocky Mountain spotted fever
- lead intoxication
- organophosphates intoxication

Based upon testing the veterinarian should be able to rule out these differentials.

The classical presentation is a young puppy that presents in a febrile condition with multisystemic manifestations including neurologic signs that develop later on in the disease.

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