Canine distemper is a contagious, incurable, often fatal, multisystemic viral disease that affects the respiratory, gastrointestinal, and central nervous systems. Distemper is caused by the canine distemper virus (CDV).

Incidence

Canine distemper occurs worldwide, and once was the leading cause of death in unvaccinated puppies. Widespread vaccination programs have dramatically reduced its incidence.

CDV occurs among domestic dogs and many other carnivores, including raccoons, skunks, and foxes. CDV is fairly common in wildlife. The development of a vaccine in the early 1960s led to a dramatic reduction in the number of infected domestic dogs. It tends to occur now only as sporadic outbreaks.

Young puppies between 3 and 6 months old are most susceptible to infection and disease and are more likely to die than infected adults. Nonimmunized older dogs are also highly susceptible to infection and disease. Nonimmunized dogs that have contact with other nonimmunized dogs or with wild carnivores have a greater risk of developing canine distemper.

Transmission

Infected dogs shed the virus through bodily secretions and excretions, especially respiratory secretions. The primary mode of transmission is airborne viral particles that dogs breathe in. Dogs in recovery may continue to shed the virus for several weeks after symptoms disappear, but they no longer shed the virus once they are fully recovered.


Symptoms


Early symptoms include fever, loss of appetite, and mild eye inflammation that may only last a day or two. Symptoms become more serious and noticeable as the disease progresses.

The initial symptom is fever (103F to 106F), which usually peaks 3 to 6 days after infection. The fever often goes unnoticed and may peak again a few days later. Dogs may experience eye and nasal discharge, depression, and loss of appetite (anorexia). After the fever, symptoms vary considerably, depending on the strain of the virus and the dog's immunity.

Many dogs experience gastrointestinal and respiratory symptoms, such as:

* Conjunctivitis (discharge from the eye)
* Diarrhea
* Fever (usually present but unnoticed)
* Pneumonia (cough, labored breathing)
* Rhinitis (runny nose)
* Vomiting


Many dogs experience symptoms of the eye:

* Inflammation of the eye Lesions on the retina (the innermost layer of the eye)
* Optic neuritis (inflammation of the optic nerve which leads to blindness)

Two relatively minor conditions that often become chronic, even in dogs that recover are:

* Enamel hypoplasia (unenameled teeth that erode quickly in puppies whose permanent teeth haven't erupted yet - the virus kills all the cells that make teeth enamel)
* Hyperkeratosis (hardening of the foot pads and nose)

In utero infection of fetuses is rare, but can happen. This can lead to spontaneous abortion, persistent infection in newborn puppies, or the birth of normal looking puppies that rapidly develop symptoms and die within 4 to 6 weeks.

Prevention

Vaccinate your puppy at 8 weeks of age every 3-4 weeks until 16 weeks of age. Another vaccine should be given at a year of age and boostered every 3 years therafter.