Distemper Flashcards
What type of virus is this?
Paramyxoviridae-enveloped
How prevalent is this?
Worldwide, super contagious, affects a large number of animals where dogs are the reservoir
How is it transmitted?
Inhaled or ingested via oronasal
What is phase 1?
Replication in the lymphoid tissue of the respiratory tract, which includes macrophages and bronchial lymph nodes
What is Phase 2?
viremia spreading after 1-5 days and extending to all lymphoid tissues
What happens if it is severe?
Depletion of vascular CD3+ T cells and CD21+ B cells along with necrosis and depletion of lymph node cortical areas
What are the two main events that happen with distemper?
Immune suppression and leukopenia
What type of immunity is needed to protect against this?
Cell mediated AND humoral. Viremia is determined by specific humoral response during that period. If no neutralizing antibodies, the virus will spread.
What is Phase 3?
Also called mucosal phase because it spreads to respiratory, GI, urogenital epithelium due to the virus’s pantropic nature. This is when the clinical signs happen
What are the clinical signs?
Biphasic fever: if transient, then the disease is subclinical but once the second fever comes, they will have clinical signs like serous nasal discharge, mucopurulent ocular discharge.
When are neuro signs seen?
During a longer course of the disease; can see encephalomyelitis, localized muscle twitching/myoclonus, and chewing gum fits. After systemic infection can see seizures and ataxia from cerebellar effects and posterior paralysis from spinal cord effects. Acute is 2-3 weeks after infection and subacute is 2-12 weeks.
What is the pathogenesis of acute CNS infection?
it targets neurons and glial cells and leads to grey matter disease (neuronal degeneration and inflammation)
What’s the pathogenesis of subacute CNS infection?
Targets oligodendrocytes and leads to a down regulation of myelin (white matter disease)
What’s the typical CNS disease?
Mix of grey and white matter
What is chronic distemper encephalitis?
Also called old dog, can be seen in vx old dogs with no infection, the antigen is detected in the brain but it is noninfectious and caused by an inflammatory reaction
What happens after infection?
Cutaneous hyperkeratosis: hard pad disease of the foot and calluses on the nose. Enamel hypoplasia since it targets ameloblasts.
What lesions can be seen?
Bronchopneumonia, enteritis, pustular dermatitis, interstitial pneumonia. Neuronal degeneration and inclusion bodies of the glial cells and neurons
How is this diagnosed?
Febrile dogs with multisystemic lesions, unvax dogs between 3 and 6 months mostly affected.
What has the highest viral loads and would be good for samples?
Urine, tonsils, conjunctival swabs, whole blood
What’s the prognosis?
Supportive therapy but poor if dogs show acute, progressive, severe neuro signs.
What about prevention?
Core vaccine, MLV that should not be used in pregnant or lactating dogs. Recomb canarypox vx for ferrets and zoo species.
