You might not think so from the name, but canine distemper has nothing to do with a dog’s temperament! Canine distemper is a viral disease that causes respiratory and neurological signs, and changes in certain areas of the skin – particuarly the nose and paws. In fact, one old name for the disease caused by the virus was ‘hardpad’. The virus is a close relative of the measles virus that affects humans.
Canine distemper virus, or closely related viruses can also affect and cause disease outbreaks in a wide range of wild species, including ferrets, mink, otters, bears, big cats, non-human primates and even Asian elephants.
The main route of infection is via aerosol spread – the viral particles are spread by respiratory secretions from infected animals. Unlike some other viruses (for example canine parvovirus) canine distemper virus does not survive well in the environment, so direct contact with infected animals is usually required.
Shortly after infection, dogs will often have a fever for a few days. However, this may not be noticed unless they are also run-down or off their food. They then return to normal for a few days, before the fever recurs. This time the fever is accompanied by lethargy, poor appetite, discharge from the nose and eyes, and often laboured breathing and gastrointestinal signs.
More serious cases develop neurological signs – circling, head tilt, flickering eye movements (nystagmus), muscle twitching and seizures, and weakness or even paralysis. Seizures may be partial, involving only the head or jaw, or generalised tonic-clonic seizures. Generally, dogs that develop neurological signs are less likely to respond to supportive treatment. Even if they go on to recover, they may be left with some neurological signs for the rest of their life.
Distemper is a very serious condition. As it is a virus, there is no specific cure; cases simply have to be nursed, and secondary infections treated with antibiotics where they occur. Dogs that are severely affected with neurological signs may need to be euthanased (put to sleep) due to the severe impact the disease has on their quality of life.
As it is a viral disease, good immunity to distemper can be produced by vaccination with a modified live vaccine. After the puppy course, and a vaccination at 1 year of age, re-vaccination is recommended every three years.
Distemper is now rarely seen in the UK due to widespread uptake of vaccination. However, the disease has not been eradicated, especially as wildlife species can also carry virus. In 1990, there was an outbreak of distemper in Finland, after no cases had been seen in dogs for 16 years. This was thought to be due to a combination of the number of vaccinated dogs falling, and a batch of vaccine that wasn’t as effective as it should have been. This shows how important it is that we continue to vaccinate against infectious illnesses, even if they appear to be no longer common.
MSD veterinary manual: Canine Distemper Overview
“Outbreak of canine distemper in vaccinated dogs in Finland”. Veterinary Record 141(15) 380-3. 1997