Canine Distemper a real killer

Yesterday we admitted into the hospital an unvaccinated sick puppy.  Symptoms of the puppy included a fever, anorexia, dehydration, screaming when touched, muscle twitches and an inability to stand on it's own.  Following blood work and based on its fever and neurological symptoms our diagnosis was canine distemper;  a highly contagious viral disease of dogs seen worldwide.  Besides being transmitted by dogs, distemper is also carried by raccoons and coyotes, often seen in our neck of the woods.

Distemper initially reproduces in the lymphatic tissue of the respiratory tract. Once within the lymphatic tissues, it spreads to the respiratory system (lungs and nasal passages), the GI tract, as well as the central nervous system and optic nerves.  How severely a dog will be effected by the virus depends on its level of immunity; thus puppies are effected the most severely as their immune systems are poorly developed.

As with most viruses, symptoms begin 3-6 days after exposure starting with a fever and inappetence.  The fever subsides for several days before a second fever occurs,  this may be accompanied by serous nasal discharge, mattery eyes, and anorexia. GI and respiratory signs may follow and are usually complicated by secondary bacterial infections. Inflammation of the brain (encephalitis) is a common symptom seen in puppies.  Once the brain is infected the dog can suffer with fever, confusion, drowsiness, and fatigue and advance to more serious symptoms of  seizures or convulsions with drooling and often chewing movements of the jaw (gum chewing fits), involuntary twitching of muscles, and paresis or paralysis.  The seizures become more frequent and severe, and the dog may fall on its side and paddle its legs; involuntary urination and defecation (grand mal seizure, epileptiform convulsion) often occur. A dog may exhibit any or all of these neurologic signs in addition to others in the course of the disease. The course of the systemic disease may be as short as 10 days, but the onset of neurologic signs may be delayed for several weeks or months.

Chronic distemper encephalitis (old dog encephalitis, [ODE]), a condition often marked by ataxia, compulsive movements such as head pressing or continual pacing, and incoordinated hypermetria, may be seen in adult dogs without a history of signs related to systemic canine distemper. The development of neurologic signs is often more progressive.  Dogs with ODE are not infectious. The disease is caused by an inflammatory reaction associated with persistent canine distemper virus infection in the CNS.

Treatment is directed at limiting secondary bacterial invasion with antibiotics, supporting fluid balance, and controlling nervous manifestations with anticonvulsants. No single treatment is specific or uniformly successful. Dogs may recover completely from systemic manifestations, but good nursing care is essential. Despite intensive care, some dogs do not make a satisfactory recovery.

Prevention: Vaccinate!! Vaccination for puppies should begin at 6 weeks of age and boostered every 3-4 weeks until 16 weeks of age.