The genetic mutation has been localized to the dog leukocyte antigen class II on chromosome 12. This mutations is similarly responsible for hypertrophic osteodystrophy in the Weimaraner, anal furunculosis in German shepherds and hypoadrenocorticism in the Nova Scotia Duck Tolling Retriever. The mutations results in autoantibodies against glial fibrillary acidic protein +ve astrocytes.
This is a progressive and fatal disease affecting 1 – 2% of Pugs, usually before 7 years of age. There has been no laboratory evidence for an infectious cause, and the etiology is now presumed to be immunologic.
Pug dog encephalitis has been likened to fulminate atypical forms of human multiple sclerosis in its form and strong association to a specific human leukocyte antigen class II genotype.
Clinically affected pugs present as either an acute cases, with onset and progression of clinical signs occurring within 2 weeks, or a chronic form ranging from 4 to 6 months, showing various clinical signs with progressive ataxia, mental unresponsiveness, partial or full seizures, partial blindness, circling, ataxia and eventual recumbency, dementia and death.
Diagnosis is based on presenting clinical signs, histopathological evidence of perivacular encephalitis and exclusion of other causes of encephalitis.
Histopathologically, the affected regions show characteristic wide distribution of degenerated neurons with glial satellitosis and neuronophagia and prominent perivascular cuffing with lymphoid cells. The encephalitis is usually restricted to the cerebrum in Pugs, whereas other parts of the brain and brainstem may be involved in other breeds.
DNA testing is considered a definitive diagnosis.
- Texas A&M
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