What is it?
Distemper is an infectious disease of dogs, also known as "hardpad". It is a very serious condition, and has a mortality rate of approximately 50%; in addition, even dogs who survive and appear to recover may develop symptoms later in life due to the original infection.
What causes it?
Distemper is caused by Canine Distemper Virus - a viral infection closely related to measles. Dogs can contract it by accidentally inhaling or swallowing fluid droplets from an infected dog (produced by the infected dog sneezing them out, but also in the vomit, diarrhoea and urine). Foxes and other wildlife may act as a reservoir for the virus, accounting for sporadic outbreaks in unprotected dogs.
What dogs are at risk?
Any unvaccinated dog is at risk from Distemper; however, if the percentage of dogs in the area that are vaccinated is high enough, the risk is relatively low as the virus will not be able to become established in the population. The more people who choose not to vaccinate however, the higher the risk is for everyone's pets.
What are the symptoms?
Initially, there is a fever, which peaks within a week and may not be noticed. However, a few days later it returns, also causing a runny nose and runny eyes; this is rapidly followed by vomiting and diarrhoea, and a thickening of the skin on the footpads (hence "hardpad"). Some dogs will develop infection of the brain and spinal cord, causing wobbliness, paralysis, seizures or a coma, About half of all infected dogs will die or need to be put to sleep, but this may take weeks or even months. In recovered dogs, some will have damage to their eyesight or persistent neurological problems and a certain percentage seem to be fine but will go on to develop "Old Dog Encephalitis", a degenerative brain disease in later life. This usually causes seizures or a "dementia-like" syndrome.
How is it diagnosed?
Clinical disease is relatively rare nowadays; however, compatible symptoms in an unvaccinated dog are highly suggestive. Confirmation of the diagnosis usually requires virus isolation in a specialist lab from blood, fluid or tissue samples.
How can it be treated or managed?
There is no specific treatment available; the standard treatment is supportive (with fluids and symptomatic relief - e.g. antiemetic drugs for vomiting, or anticonvulsants for seizures). Antibiotics are often used to help prevent secondary infections which may in themselves prove fatal. At all times, however, the infected dog must be kept in quarantine, away from other dogs, to minimise the risk of transmission of the infection.
Can it be prevented?
Yes - the modern Distemper vaccine is very effective, and once the primary course (2 injections 2-4 weeks apart, then a booster at 12 months) is completed, only needs topping-up every 3 years (to ensure that protection is maintained in the vast majority of dogs).