Canine distemper is a highly contagious and potentially fatal viral disease caused by the Canine Distemper Virus (CDV), a member of the Paramyxoviridae family. Despite advances in vaccination, this disease remains a significant threat, particularly in unvaccinated dogs and wildlife populations such as foxes, wolves, raccoons, and skunks.
Pathogenesis
CDV primarily targets the respiratory, gastrointestinal, and central nervous systems. After initial infection through respiratory droplets, the virus replicates in the lymphatic tissue of the respiratory tract, leading to viremia. If the immune response is insufficient, the virus spreads to epithelial and nervous tissues, causing multisystemic disease.
Clinical Signs
The clinical presentation of canine distemper can vary widely depending on the stage of infection and the systems affected. Common signs include:
- Respiratory: Nasal discharge, coughing, and pneumonia.
- Gastrointestinal: Vomiting and diarrhea.
- Neurological: Seizures, ataxia, myoclonus (involuntary muscle contractions), and behavioral changes.
- Dermatological: Hyperkeratosis of the footpads and nasal planum (“hard pad disease”).
Some dogs may show mild signs, while others progress to severe systemic involvement. The neurological signs can appear weeks to months after recovery from the initial illness.
Diagnosis
Accurate diagnosis requires a combination of history, clinical signs, and laboratory testing:
- History: Exposure to unvaccinated or infected dogs.
- Imaging: Chest radiographs may reveal signs of pneumonia.
- Laboratory Tests:
- PCR testing of swabs (conjunctival, nasal, or throat).
- Rapid Test for CDV-specific antibodies/antigens.
- Cytology: Detection of inclusion bodies in epithelial cells or blood smears.
Treatment
There is no specific antiviral therapy for CDV. Treatment focuses on supportive care:
- Fluid Therapy: To correct dehydration and electrolyte imbalances.
- Antibiotics: To prevent or treat secondary bacterial infections.
- Anticonvulsants: For managing seizures.
- Nutritional Support: To counteract anorexia and weight loss.
Prognosis varies; dogs with mild respiratory or gastrointestinal signs may recover, while those with severe neurological involvement often have a guarded to poor prognosis.
Prevention and Control
Prevention primarily involves vaccination, which is highly effective and essential for puppies and unvaccinated dogs. Puppies should receive their first distemper vaccine at 6-8 weeks of age, followed by booster shots according to veterinary recommendations. Controlling the spread includes isolating infected animals, maintaining hygiene in kennels and communal spaces, and avoiding contact between unvaccinated pets and potentially infected animals. Public awareness and regular veterinary check-ups are key to reducing outbreaks and safeguarding canine health.
