Canine Distemper: Transmission, Diagnosis, Treatment

Article written by Isabelle Vixège, DVM 

Once common in France, thanks to vaccination, canine distemper is a serious viral disease in dogs. Puppies are particularly susceptible to it. Currently, there is no treatment for this virus. Vaccination is recommended from 8 weeks of age.

1. Definition: What is canine distemper?

Canine distemper is caused by a Morbillivirus from the Paramyxoviridae family; it is related to the human measles virus. It attacks the epithelial cells of the respiratory system and digestive tract. Neurological forms due to demyelination (destruction of the myelin that forms the sheath of nerve fibers) are also observed.

This disease was discovered in 1905 by veterinary surgeon Dr. Henri Carré, hence its French name. In English-speaking countries, it is called Canine Distemper Disease. It is also sometimes called "puppy disease" or "young dog disease," because it is particularly virulent in puppies. However, it can affect any unvaccinated animal.

2. Transmission: How is it caught?

2.a Transmission between animals

Canine distemper is a contagious virus among dogs. It is transmitted through contact with a sick animal. Secretions such as droplets from sneezes or coughs, diarrhea, etc., are contaminating. Indirect contamination (e.g., by carrying the virus on clothes) is possible.

Dogs are not the only species affected by the canine distemper virus; it also affects ferrets and wild carnivores such as foxes and wolves.

2.b Transmission to humans

Humans are not susceptible to canine distemper. Therefore, there is no risk in being around a sick animal (although basic hygiene should always be observed) as this virus is not contagious to humans.

Cats are also not affected by Distemper.

3. Identification: What are the main symptoms of canine distemper?

The incubation period for canine distemper ranges from 3 days to one month. In an affected dog, initially, hyperthermia (a high fever) is observed, followed by various clinical signs. Symptoms of canine distemper can be digestive, respiratory, cutaneous, and neurological.

• Lethargy, loss of appetite, emaciation
• Vomiting, diarrhea
• Coughing, sneezing, nasal and ocular discharge
• Thickening of the nose and paw pads
• Muscle contractions (myoclonus), abnormal gait, seizures

Neurological symptoms usually appear late in the disease progression. They can also be the only symptoms present. They worsen the prognosis.

Minor forms are sometimes observed in vaccinated adult dogs (transient fever, mild rhinitis, or cough).

Canine distemper is particularly formidable in communities (shelters, kennels, etc.) where it spreads like wildfire. Sick animals must be isolated, and premises thoroughly disinfected.

If you have the slightest doubt, it is important to consult a veterinarian.

4. Disease Diagnosis: How to confirm canine distemper?

In a sick animal, a PCR test can be performed to detect the virus's DNA. Samples are taken from nasal or ocular discharge, urine, blood, or even cerebrospinal fluid in neurological forms.

PCR identifies the viral strain (the "variant") responsible.

The virus can also be sought by histological analysis of mucous membranes (microscopic observation of viral inclusions in cells).

Did you know? In the context of selling a puppy, canine distemper is a redhibitory defect. This means that if the pathology declares itself within 7 days of the transaction, the transaction can be canceled.

5. Treatment for canine distemper: How to cure canine distemper in dogs?

Unfortunately, there is no specific treatment for this viral disease.

5.a. Treatment for puppies

Care will consist of supporting the general condition and immune system, combating symptoms and secondary infections. For this purpose, the young dog may be hospitalized for IV fluids. In case of digestive symptoms, anti-vomiting drugs and intestinal protectants are administered. A superimposed bacterial pneumonia will be treated with broad-spectrum antibiotics.

5.b. Treatment for dogs affected by the virus

It is identical to that for puppies. The risks of dehydration in cases of gastroenteritis are lower. During hospitalizations, affected dogs must be kept in a specific kennel to avoid contaminating other animals.

6. Prevention: What vaccine for canine distemper?

Before the discovery of the vaccine, France was regularly affected by epidemics. Thanks to massive vaccination campaigns, canine distemper has become rare in the country. But we must not let our guard down, as this viral disease has not completely disappeared.

Several vaccines are available against this disease. The WSAVA (World Small Animal Veterinary Association) recommends the following vaccination protocol for puppies:

• First vaccination around 8 weeks (not before 6 weeks)
• First booster at 12 weeks
• Second booster at 16 weeks
• Third booster between 6 and 12 months

Adult dogs should then be revaccinated every 2/3 years.

Rare severe cases of canine distemper are observed in properly vaccinated dogs. These are thought to be so-called wild strains (i.e., genetically different from the one included in the vaccine).

7. Prognosis: What are the chances of recovery, and is it a fatal disease?

Canine distemper is a serious disease that can be fatal. It is considered fatal in approximately 50% of cases. The appearance of neurological symptoms is a bad sign.

There are no breed or sex predispositions. Puppies over 3 months are particularly susceptible because they are no longer protected by maternal antibodies (if the mother is vaccinated).

Regular vaccination is the best way to protect your dog against the canine distemper virus.

Article written by Isabelle Vixège, DVM