Gross Examination(1)bronchopustlesent
Thymic atrophy (shrinkage) in
Hyperkeratosis (hardening) of 
nose and footpads
Secondary Infections:
Interstitial pneumonia
Skin pustules
Necrosis of lymphatic tissue
                                               6.Enteritis (inflammation of the gut)      7. Skin Pustules                                            8. Bronchopneumonia

Histological or Microscopic Examination(1)
Cytoplasmic/Intranuclear inclusion bodies in:
GIT (gastrointestinal) system
 Neurological: gliosis
perivascular cuffing
nonsuppurative leptomeningitis
  Increased CSF (cerebral spinal fluid) protein

9: Distemper viral body inclusions present
in erythrocytes (red blood cells) and                                                                   10. Lung lesions in an African wild dog with canine distemper. leukocytes (white blood cells).                                                                          Hematoxylin and eosin staining.
A. Bronchiole occluded by inflammatory cells and cell debris.
B. Detail of A, showing multiple eosinophilic intracytoplasmic viral inclusions (arrows) in bronchiolar epithelium.



Distemper should be considered as a diagnosis for any
febrile (feverish) puppy with multisystemic disease, with associated
 neurological involvement (1). Diagnosis must be made
on the basis of vaccination history and clinical signs
and laboratory tests (2).

 The diagnosis may be confirmed by the following:

Histological lesions:

The presence of intracellular inclusion bodies in leukocytes, conjunctival or vaginal imprints, bronchial cells, urine sediments, or CSF is sought (1,6). Note, a negative result does not rule out CDV infection (2).

Immunofluorescent assay:

Viral antigens (proteins) may be detected in certain tissues including: conjunctival or vaginal imprints, tracheal cells and epithelia (1). In this assay, special proteins labeled with a fluorescent chemical are used to detect and bind viral antigens present in various tissue samples. As with histology, a negative result does not rule out the possibility of CDV infection (2). Virus isolation is not available at most veterinary diagnostic laboratories (6).


The serological presence of a viral specific IgM (antibodies) or an increased ratio of CSF to serum viral specific IgG (antibodies) will indicate the presence of CDV infection (1). The IgM antibody persists in dogs with distemper for 5 weeks to 3 months, depending on virus strain and host response, and may be evaluated using an ELISA test (6). Serology itself is not considered diagnostic for CDV as dogs may die without significant antibody production, and chronically infected dogs may have antibody levels comparable to vaccinated dogs (6).

Polymerase chain reaction (PCR) is a technique that helps identify viral nucleic acid. It is usually more sensitive than either histological examination for viral inclusion bodies or immunofluorescence (2,6).

Spinal Tap: 

Cerebrospinal fluid (CSF) may be examined for viral specific antibodies, interferon, elevated levels of particular proteins and mononuclear cells that indicate the presence of the virus (2,6).

Blood work is often non specific and non helpful in the diagnosis of CDV. In some cases, early infection may produce a lymphopenia (low white blood cell count). Leukocytosis  (high white blood cell count) may occur as the infection progresses (2). Thrombocytopenia (low platelet count) and monocytosis (high monocyte count) may be found (6).

Radiography (X-rays), Ultrasound and CT Scans may be used to nonspecifically diagnose pneumonia associated with CDV(2).

Differential diagnoses include (1,2):


11. Coccidiosis                               12. Neosporosis                               13. Leptospirosis

toxoplasma skull tick
    14. Toxoplamosis                    15. Organophosphate Poisoning              16. Rocky Mtn. Spotted Fever
   Gastroenteritis: Giardiasis, Parvovirus, Coronavirus, Toxin Ingestion
    Infectious Canine Hepatitis (Adenovirus)
    Kennel Cough