Canine Distemper is a Deadly but Preventable Disease

The canine distemper virus is the leading cause of canine infectious disease deaths. The virus is widespread and very resistant to cold; most distemper cases are seen in the fall and winter. Canine distemper virus (CDV) infection is usually seen in unvaccinated dogs three to six months old and kills more puppies than adults. A highly contagious disease, it is made more lethal by severe secondary bacterial infection.

What is the course of the disease? CDV is unstable and is weakened by exposure to heat, detergents, and sunlight. The virus is harbored in the fluids or secretions from the respiratory system of an infected dog. The most common means of transmission is aerosol droplets. It is spread by direct contact with other dogs and possibly with contaminated objects. CDV is shed in the feces and urine of infected dogs, and probably through the mother's placenta to her puppies.

After it enters the upper respiratory tract, CDV spreads to the tonsils and lymph nodes, where it replicates. Then it enters the blood stream, where it is transported to the cells that line the surfaces of the body, including the intestinal and respiratory tract.

What are the symptoms of canine distemper? About half of infected dogs show little illness, but the rest develop severe disease. Each infected dog does not display every symptom, and the disease course with the individual. After initial infection there is a six- to fifteen-day incubation period with no symptoms. Then a high fever and malaise (depression) develop. The dog recovers from these symptoms and seems to be fine for up to a week. Eventually a clear nasal discharge develops which looks like an upper respiratory infection, followed by listlessness, fever, decreased appetite, and a greenish nasal discharge. Some dogs will recover if treated at this stage; others improve temporarily. Later symptoms can include cough, diarrhea, vomiting, a yellow nasal discharge, conjunctivitis with sticky lids, anorexia, smelly diarrhea, skin eruptions on the belly or between the hind legs, and development of thick skin on the nose and food pads called hard-pad. Because of diarrhea and vomiting, the animal may become dehydrated.

The virus may also spread to the nervous system, causing neurologic symptoms. Slobbering, head shaking, and chewing movements are followed by epileptic-like seizures. The dog may become aggressive, show confusion and lethargy, wander aimlessly, and even fall over and kick his feet. These are symptoms of encephalitis, or brain inflammation. Another neurologic symptom is chorea, painful, rhythmic jerks and twitches all over the body. If the dog recovers, the chorea will be permanent but will probably become less severe. In addition to all the other symptoms, there may be difficulty breathing due to lung inflammation and an unkempt appearance to the fur. The spleen may become enlarged.

How is canine distemper diagnosed? Since the symptoms of canine distemper are similar to those of a number of diseases, the diagnosis is problematic. Be aware that canine distemper and rabies can look similar, so when in doubt, handle the dog with caution. There is no test that will give an accurate diagnosis of canine distemper. It is usually arrived at by examining the history, symptoms, and response to treatment, and lab work such as blood smears.

What's the treatment for canine distemper? No treatment exists that kills the virus once the dog is infected. Recovery really depends on the state of the dog's immune system: the healthier the dog, the more likely that he will survive. Supportive care is very important and can lead to recovery in a few days to a week. But distemper often progresses despite treatment. Some animals seem to recover, then relapse.

The real purpose of treatment for canine distemper is to buy time for the immune system to respond to the viral attack. Fever and infection are treated with antibiotics. Dehydration, vomiting, and diarrhea may require IV fluids. Neurologic symptoms can be treated with anti-seizure medication, or if they are very severe, the vet may recommend euthanasia. Holistic veterinarian Dr. Richard Pitcairn believes that conventional drugs don't do much good and may increase the chances of developing encephalitis. Instead, he recommends homeopathy and nutritional therapy, including fasting the dog on vegetable broth and pure water for up to a week along with high doses of vitamin C. Any eye discharge can be treated with saline solution followed by cod liver oil or olive oil.

How can you prevent canine distemper? The only effective method of protecting your dog against CDV infection is vaccination. Puppies should receive a distemper vaccination starting at six to eight weeks of age, with boosters at three-week intervals until the course is complete. After the initial shots, periodic boosters are recommended. You should discuss the frequency of the boosters with your vet.

After the disease has run its course, in order to prevent recontamination it is important to disinfect contaminated areas as well as washing food and water bowls and other contaminated items with a solution of one cup of chlorine bleach in a gallon of water.

Fortunately, canine distemper is not a zoonotic disease, that is, there is no evidence that the virus can be transmitted to cats or humans.