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Synonym: Carre's disease, hard pad disease
Definition
- Acute febrile contagious disease of dogs caused by paramyxovirus and characterized by fever, acute catarrhal inflammation of various mucous membrane, pneumonia and in some cases skin lesions and involvement of CNS
Aetiology
Susceptibility
- Animals affected: Dogs, Foxes, Jackals Ferrets, and Wild Canidae
- Seals in Baltic Seas affected with phocid virus which is identical with CD
Transmission
- Ingestion and Inhalation
- CD almost always occurs with secondary Bacterial infection
- Bordetella bronchoseptica (pneumonia)
- Salmonella Sp (GI Lesion)
Pathogenesis
- Incubation period: 5 days.
- Virus infects all types of tissues (pantropic virus)
- Ingestion/ inhalation on entry
- Proliferation in local lymph node
- To blood viremia/ septicaemia
- To various tissues (skin, gastrointestinal tract, urinary, biliary tract)
- In brain vascular enodothelium
- In skin- Pustule formation due to secondary bacterial infection
- Brain- Old dog encephalitis
- Initial infection - Recovery - Distemper virus suppressed in CNS - unknown stimulus- Defective replication
- Direct damage to neurons and indirect damage to glial cells leads to produce demyelinating encephalitis
Clinical signs
- Diphasic Fever- First fever may be due to virus persits for 3 to 4 days
- Then temperature is normal upto 11 or 12th day.
- Again fever due to secondary bacterial infections
- Nasal Discharge, Conjunctivitis, Bronchitis
- Signs of Pneumonia
- Diarrhea – Dehydration / Emaciation
- Pustules on ventral abdomen/Inner thigh
- Hyperkeratosis of Digital pads (Hard Pad)
- Keratitis / Retinitis – Blindness
- Nervous symptoms – Epilepsy, chewing movements, salivation, in coordination
- muscular twitching in face, head, neck or shoulder muscles
- Torticollis, nystagmus and convulsions
Gross lesions
- Respiratory tract: catarrhal/Purulent exudates in nasal and pharyngeal mucosa.
- Purulent exudate in bronchioles – bronchoilitis capillaris
- In pure CD-Interstitial pneumonia
- In secondary bacterial infection: Purulent bronchopneumonia
- GI tract ; acute catarrh, swelling of peyer’s patches and lymph nodes.
- Heart : Hydropericardium, fatty degeneration and small haemorrhages of myocardium
- Liver: Parenchymatous degeneration/'Nut meg’ liver
- Eye: Catarrh of conjunctivitis
- Brain: Hyperemia of meninges
- Haemorrhages of Brain and spinal cord
Microscopic lesions
- Demyelination – Virus has got affinity for myelinated portion of brain and spinal cord.
- Perivascular cuffing, hemorrhages, edema of Virchow-Robin space, vasculitis, satellitosis, gliosis (with formation of gemistocytes), neuronophagic capillary proliferation, demyelination
- Inclusion bodies - Intra cytoplasmic or intranuclear inclusion acidophilic bodies (Round or Ovoid)
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Canine distemper-Intra cytoplasmic acidophilic
bodies (Round or Ovoid)
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The inclusion bodies are found in
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Respiratory tract: Epithelial cells of mucosa of nose, pharynx, bronchi, bronchioles, alveolar epithelium
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Digestive tract : Ducts of liver, pancreas and salivary glands
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Urogenital : urinary tract and genital passages
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CNS : Neurons and microglia
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Cytoplasmic inclusions in circulating neutrophils and erythrocytes is of diagnostic importance.
Diagnosis
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Participants