♦ 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”).