Canine Distemper

Disease Overview

Canine distemper is a highly contagious, often fatal disease caused by a virus that attacks the respiratory, gastrointestinal, and the nervous systems. Contact among recently infected animals maintains the virus in a population, and a constant supply of puppies helps to provide a susceptible population for infection. Although immunity to virulent canine distemper is prolonged or lifelong, it is not as absolute after vaccination. Dogs that do not receive periodic immunizations may lose their protection and become infected after stress, immunosuppression, or contact with diseased animals.16

Merck Animal Health Solutions

For Canine Distemper


Distemper is spread through contact with bodily secretions (eg, nasal discharge), but is most commonly spread through airborne transmission (eg, sneezing and coughing).

Clinical Signs

  • Fever
  • Nasal discharge
  • Coughing
  • Vomiting
  • Diarrhea

Risk Factors

Young dogsDogs that come from shelters, rescue centers, breeding kennels, or pet storesBoarding at a kennel or doggie daycareVisiting groomers, dog parks, or engaging with other dogs on a daily basisDogs that live in multi-pet homes


16. Green C, Appel M. Canine distemper. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 3rd ed. St. Louis, MO: Saunders/Elsevier; 2006:27.