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Canine Distemper Virus This is a condition which affects the nervous system, the gastrointestinal system and the respiratory system. The highest incidence is in the 3-6 month age group. Similar virus to that which causes human measles (morbillivirus). Spread by air in droplets from the respiratory tract, the virus does not survive for long in the environment, so spreads most rapidly when dogs are in close contact. Now largely controlled by vaccination. Infection occurs by inhaling the virus. It replicates in the lymphoid system, then spreads to the nervous tissue and the epithelial cells lining the intestinal and respiratory passages. In most dogs the immune response will eliminate the infection. In those who do not the disease takes up to 2 weeks to develop, nervous signs do not appear until 4-5 weeks after initial infection. Onset is gradual, often with a wide variety of clinical signs, initially dull, inappetant, high temperature, conjunctivitis, vomiting and diarrhoea then develop followed by a cough and increased respiratory rate. Thick nasal discharge, sneezing and conjunctivitis are next, this can last for 2-3 weeks. By the third week of illness hyperkeratosis (thickening of skin) on the foot pads occurs. By the fourth week nervous signs such as muscle spasms, twitching, restlessness, apprehension, even classical epileptic fits can develop. Severely affected animals can get a hind limb paralysis, milder cases develop balance problems and difficulty with coordination. Animals that survive can have permanent neurological defects Treatment options are limited, once nervous signs appear the prognosis becomes extremely poor. Aside from antibiotics to prevent secondary infection and phenobarbitone to control fits treatment is symptomatic. Typical support therapy will include fluids, electrolytes, B vitamins, and nutritional support Vaccination is an extremely effective means of control. Around 95% of pups at 13 weeks old will mount an effective immune response. |
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