Canine distemper is a devastating, sometimes fatal, virus that causes symptoms such as runny nose, cough and pneumonia, watery eyes, gastrointestinal disturbance, vomiting, diarrhea and neurological disturbances, which may be permanent in dogs that survive the acute phase of the illness. Although difficult to treat, the virus can be prevented easily with a series of distemper shots.
Prior to the development of the canine distemper shot, in the 1950s, distemper was a leading cause of death among domesticated dogs in the United States and elsewhere. Since vaccinating puppies against the illness has become a regular practice, distemper is now a rare occurrence in the general canine population and occurs most frequently in shelters, where large groups of stray animals are housed together.
Canine distemper shots are administered to puppies over a series of weeks and to dogs every 1 to 3 years to prevent canine distemper. They are often combined with canine parvovirus vaccines, as well as parainfluenza, leptospirosis and coronavirus.
Canine distemper vaccinations are available as a "live" vaccine or in a recombinant format. In the live vaccine, the virus is delivered in a modified version, which will induce an immune response without causing illness in a dog. The recombinant version of the vaccine introduces a live virus that is not associated with distemper as a carrier for a deactivated portion of the distemper virus to induce an immune response in the dog. The recombinant version is safer, as there is no possibility of the distemper virus becoming active in the dog, whereas the live version of the vaccination may rarely cause distemper.
The distemper vaccination is usually given to puppies when they are between the ages of 6 and 8 weeks old. Boosters are given every 2 to 4 weeks after the initial shot until the puppies are 16 weeks old. One year later, they receive another vaccine, and booster vaccinations are given again from 1 to 3 years later, based on antibody levels found in blood tests.
Some veterinarians caution against the practice of delivering "booster" vaccinations, including boosters for the distemper vaccine. They caution that overwhelming the immune system with too many live vaccines can cause chronic illness and even cancer in pets, in addition to other adverse reactions, including dry skin, skin eruptions, arthritis, joint maladies, urinary tract infections and seizure disorders. Speak to your veterinarian about the benefits versus the risks of repeated distemper vaccinations for your dog.