Canine Distemper
NECROPSY REQUEST
CLINICAL DIAGNOSIS: DDx: Distemper, Rabies, Tetanus.
HISTORY: Owner got from animal shelter one week prior to euthanasia.
One week history of upper respiratory signs. Steady decline in stamina.
Hyperesthetic around face. Stiff-legged gait. Discharge from eyes and nose.
Excessive salivation. Aggressive. Muscle wasting.
Cautions: Rabies suspect.
CLINICAL QUESTIONS: R/O [rule out]: Distemper and rabies.
NECROPSY GROSS REPORT
ANIMAL IDENTIFICATION: A 13.86kg (30 lb.), adult, white and tan, castrated male, Siberian Husky dog in fair body condition is presented for necropsy.
INTEGUMENTARY AND
SPECIAL SENSES: The subcutis along the right lateral aspect of the ribs
is filled with small amounts of red gelatinous fluid (edema).
RESPIRATORY: The trachea is filled with a moderate amount of white
foamy fluid (edema). The lungs are diffusely mottled red to dark red to
purple, heavy, and firm, with multiple soft irregular nodules in the
parenchyma (bronchointerstitial pneumonia).
URINARY (Right kidney weight: 56g; Left kidney weight: 60g):
Multifocal, up to 1cm in diameter, red, flat areas are in the mucosa of the
urinary bladder (ecchymoses).
DIGESTIVE: Numerous, up to 5cm long, yellow to tan, flat, segmented
parasites (tapeworms) are within the lumen of the small intestine.
NERVOUS: The meningeal blood vessels are dilated and prominent
(congestion).
CARDIOVASCULAR (Heart weight: 0.104kg. The right ventricular free wall
is 1.8cm in width. The left ventricular free wall is 0.6cm in width.),
HEMIC AND LYMPHATIC (Spleen weight: 30g), GENITAL, LIVER
AND PANCREAS (Liver weight: 0.624kg), ENDOCRINE, MUSCULOSKELETAL:
No significant lesions observed.
POSTMORTEM ANALYSIS AND DIAGNOSIS: The cause of death is
euthanasia. The history of neurologic signs and the presumed
bronchointerstitial pneumonia on necropsy are suggestive of canine distemper.
Samples of lung and brain are submitted to TVMDL for canine distemper virus
testing. A brain sample is submitted to the Texas Department of Health for
rabies testing. Histopathology of selected tissues is pending.
TENTATIVE DIAGNOSIS: Bronchointerstitial pneumonia, presumed.
(Fig. 1 The lungs are uncollapsed, dark red and mottled, and are diffusely firm, consistent with an interstitial pneumonia pattern.)
NECROPSY HISTOPATHOLOGY REPORT
MICROSCOPIC LESIONS:
Lung: Severe, diffuse, subacute, bronchointerstitial pneumonia with syncytial
cells and intranuclear and intracytoplasmic inclusion bodies.
Liver: Severe diffuse congestion.
Stomach: Mild, multifocal, acute, epithelial cell necrosis.
Heart, Kidney, Brain, Urinary bladder: No significant lesions.
DIAGNOSIS: Canine distemper.
(Fig. 2 At low magnification, note the congested blood vessels, thickening of alveolar walls, and the inflammatory cells within alveolar spaces.)
(Fig. 3 At high magnification, note the syncytial cells (thick arrow) formed by viral-induced fusion of epithelial cells. Intracytoplasmic viral inclusion bodies (thin arrows) are present within some syncytial cells.)
(Fig. 4 Another high magnification view, showing an intranuclear inclusion body (thick arrow). Alveolar spaces contain many neutrophils (thin arrow) and fewer macrophages (arrowhead).)
INTERPRETIVE SUMMARY/COMMENTS:
The
histologic lesions in the lungs are consistent with canine distemper virus
infection. A fluorescent antibody (FA) test for canine distemper virus was
positive in both the lung and brain. Brain samples were negative for rabies
virus.
ANCILLARY LABORATORY RESULTS:
Brain, Lung (FA): Canine distemper virus - Positive.
Rabies test: Negative.
