Distemper in dogs is caused by a very contagious virus called canine distemper virus (CDV). Infection is typically spread through mouth, nose, or eye secretions or fluids (e.g. particles from sneezing or coughing). Several strains exist which can result in different degrees of illness.
Canine distemper can affect the respiratory tract, gastrointestinal tract, skin, eyes, and/or the nervous system including the brain. Infections can be fatal. Distemper symptoms can include lying around more, fever, poor appetite, cough, runny nose or eyes, loose stool, vomiting, abnormal areas of skin swelling or thickening, trouble walking, twitching, and/or seizures. Young dogs are at highest risk for infection. The disease can also affect wildlife such as raccoons and foxes, and occasionally ferrets and cats.
No cure exists for canine distemper. Fortunately, a distemper vaccine (i.e. shot) is available. If your dog is appropriately vaccinated and boostered, he or she will not be able to become infected.
Distemper Vaccine for Dogs
Distemper vaccines are typically combined with other vaccines to reduce the number of injections needed. Several combination vaccines are available. DHPP or DAPP vaccines vaccinate for distemper virus, adenovirus-1, adenovirus-2 which causes hepatitis, parvovirus, and parainfluenza virus. DHLPP vaccines vaccinate for the same diseases as DHPP/DAPP as well as strains of leptospirosis. You may also hear these vaccines referred to as 5-in-1 or 5-way, 6-in-1 or 6-way, or 8-in-1 or 8-way vaccines depending on the combinations of vaccines being used in one vaccine shot.
When should dogs receive a distemper vaccine?
Dogs can be vaccinated as early as six weeks of age. This is especially important to know because puppies are at higher risk for becoming infected. Puppies should have their first distemper vaccine or shot at six to eight weeks old, then have the vaccine boostered every two to four weeks until they are sixteen weeks of age. After this initial set of puppy shots, they will need a booster at one year of age, then another booster every one to three years for the rest of their lives. Older dogs will need to receive at least two vaccines, two to four weeks apart, followed by a booster vaccine in one year and then every one to three years thereafter.
Distemper Vaccine Side Effects
For the most part, the distemper vaccine and most of the vaccines it can be combined with are very safe. Swelling or pain at the injection site is not uncommon. Some pets may be a little tired for the first 24 hours or so after being vaccinated. These are mild but normal effects of most vaccines and should improve with time and rest.
Some dogs may experience a vaccine reaction. This is a more serious side effect. Symptoms include hives or red splotches on the stomach, swelling of the face, and trouble breathing. If you notice these symptoms, call a veterinarian immediately as these symptoms can sometimes be life threatening. Dogs with a history of a vaccine reaction to distemper vaccines can sometimes continue to be vaccinated as needed. In order to do this, veterinarians will often pre-medicate dogs with steroids and/or antihistamines to prevent the reaction before it starts. Some veterinarians will also split up additional yearly vaccines over two to four weeks, such as rabies and kennel cough vaccines, to further prevent an overreaction by the immune system. Your veterinarian will be able to discuss concerns and solutions with you about whether to continue to vaccinate or not, and what to expect with future reactions.
Postvaccinal encephalitis is an inflammatory brain condition that has been reported rarely after vaccination for distemper virus. In young animals, hypertrophic osteodystrophy may be another side effect of distemper vaccine. This condition affects the growth plates of growing puppies leading to abnormal growth or bone development. Juvenile cellulitis, a skin condition associated with swollen lymph nodes and skin swelling or oozing, may also be associated with distemper vaccines in young puppies. Both hypertrophic osteodystrophy and juvenile cellulitis are rare, and the potential for the distemper vaccine to cause either issue is extremely low. Your veterinarian will be able to discuss these side effects and their risks with you thoroughly should you have any questions or concerns.