Canine distemper is a highly contagious, systemic, and viral disease of dogs. Canine distemper is also called by its other names Hard pad disease, Canine influenza, and Carres. This disease is found worldwide and it affects the respiratory, gastrointestinal, and nervous systems of dogs and puppies. This virus is also reported in different wild animals like wolves, tigers, foxes, etc.

Canine distemper virus (CDV) belongs to the Paramyxoviridae family. CDV is a fragile, enveloped, single-stranded RNA virus. It is sensitive to lipid solvents, such as ether, and most disinfectants, including phenols and quaternary ammonium compounds. Canine distemper virus is unstable outside the host. Canine distemper is transmitted mainly via aerosol droplets and also by secretions of infected animals.

Canine Distemper Pathogenesis

CDV has got an affinity for epithelial cells of the respiratory and alimentary tract. Lymphoid and nerve cells are more prone to get the attack.

Pathogenesis is as follows

Virus –> inhalation –> Pharynx –> Palatine tonsil –> Macrphages –> Lymphoid vessels –> Blood vessels –> Bone –> Marrow –> Spleen –> Lymphoid tissues –> Leukopenia –> Leukocytoosis

CDV enters the animal body and propagates in through above schematic route. CDV replicates initially in the lymphatic tissue of the respiratory system. Cell associated viremia occurs and it results in the infection of the respiratory, digestive & lymphatic tissues as well as the optic and CNS nerves.

How my pet can get canine distemper?

Dogs and puppies get infected mostly through inhalation route (aerosol or droplets). Transmission of virus takes place through sneezing or coughing of infected dog or wild animal. The virus is also discharged through body secretions and excretions of the infected animal. So, virus can also be transmitted through shared food, water and utensils. Mothers can transmit the virus through placenta to their puppies. Contact between wild animals and pet animals can also increase the risk of canine distemper disease spreadness.

Unvaccinated dogs and puppies with age less than 4 months are at high risk of acquiring infection.

Canine Distemper Symptoms / Clinical Signs

1. Animal is dull & depressed
2. A transient fever usually occurs 3–6 days after start of infection (Unnoticed)
3. Leukopenia (especially lymphopenia)
4. Encephalomyelitis
5. A second fever occurs (biphasic fever)
6. Serous nasal discharge
7. Mucopurulent ocular discharge
8. Lethargy & anorexia –
9. Secondary bacterial infections along with GI and respiratory signs
10. Dogs surviving the acute phase may have hyperkeratosis of the footpads and epithelium of the nasal planum, as well as enamel hypoplasia in incompletely erupted teeth.

Depending upon the clinical signs observed, canine distemper is divided into 5 types.

Pulmonary Form

It is characterized by

1. Oculonasal discharge
2. Pharyngitis
3. Bronchitis
4. Bronchopneumonia

Pulmonary form is more prevalent than digestive form.

Digestive Form

It is characterized by

1. Loss of appetite
2. Vomiting
3. Abdominal pain
4. Foul smelling, loose feaces
5. Haemorrhagic enteritis in young pups
6. Feaces may contain blood

Nervous Form

It is characterized by

1. Restlessness
2. Excitement
3. Chewing movements
4. Excessive salivation
5. Convulsions
6. Chorea (Jerky movements of group of muscles)
7. Muscular spasms of cheeks, jaws, head, neck or limb muscles may be observed

Occular Form

It is characterized by

1. Swollen eyelids
2. Congestion of conjunctival mucosa
3. Purulent discharge from eyes
4. Ulceration of cornes may found

Cutaneous Form

It is characterized by

1. Rash
2. Vesicles
3. Pustules on skin
4. Hyperkeratitis (Skin of foot pads and nose become hard)
5. Vesicopustular eruptions on ventral aspect of abdomen (distemper exanthema)

Treatment

Symptomatic & supportive treatment will be adopted. No specific antiviral agent is used widely for treatment purpose.

1. Broad spectrum antibiotics
2. Balnced electrolyte solutions
3. Parenteral nutrition
4. Anti-pyretics & analgesic are used
5. Anti-convulsants are used.
6. Sometimes immunosuppressive therapy with anti-inflammatory or greater dosages of glucocorticoids may be needed.
7. Anticanine distemper serum may be tried to safeguard the life of the patient.

Canine Distemper Vaccination

Vaccination against canine distemper is crucial for preventing the disease. Measle virus vaccine has been used to protect dog against distemper. This vaccine can be used in pups older than 6 weeks but this vaccine is not recommended for 2-6 months old pups. Measle virus vaccine can induce immunity in the presence of greater level of maternal distemper antibodies. While use of canine distemper modified-live virus vaccines in pups can interfere with maternal antibodies and they lack successful immunization.

Modified live virus vaccines should not be used in late pregnant or early lactation bitches.

Lyme borreliosis is another disease of dogs and cats which is responsible for lamness and lethargy in animals.