How does an encephalitic tick manifest in dogs? - briefly
Infected dogs usually exhibit acute neurological signs—fever, lethargy, ataxia, tremors, seizures, facial paralysis, or altered mentation—often emerging within days of the bite. Without prompt veterinary treatment, these symptoms can progress rapidly and become life‑threatening.
How does an encephalitic tick manifest in dogs? - in detail
Encephalitic disease transmitted by ticks in dogs begins after an incubation period of 5–21 days, during which the pathogen multiplies in peripheral tissues before crossing the blood‑brain barrier. Initial manifestations are non‑specific: fever (38.5–40 °C), lethargy, loss of appetite, and muscle pain. Within 24–48 hours, neurological signs emerge and may include:
- Ataxia or unsteady gait
- Tremors and involuntary muscle contractions
- Cranial nerve deficits such as facial paralysis, drooping eyelids, or altered pupillary response
- Hyperesthesia causing exaggerated reaction to touch or sound
- Seizure activity, ranging from focal twitching to generalized convulsions
- Altered mentation, from mild disorientation to coma
Concurrent systemic abnormalities often accompany the central nervous system involvement:
- Elevated heart and respiratory rates
- Pale or icteric mucous membranes indicating hemolysis
- Hematuria or proteinuria reflecting renal involvement
- Gastrointestinal upset, including vomiting and diarrhea
Laboratory evaluation typically reveals leukocytosis with a left shift, increased inflammatory markers (C‑reactive protein, fibrinogen), and, in severe cases, mild thrombocytopenia. Cerebrospinal fluid analysis shows pleocytosis, elevated protein, and occasionally detectable pathogen DNA by PCR. Imaging (MRI or CT) may demonstrate focal edema or diffuse encephalitic changes, but normal scans do not exclude disease.
Prognosis correlates with the rapidity of therapeutic intervention. Early administration of anti‑tick antibiotics (e.g., doxycycline) combined with anti‑inflammatory agents (corticosteroids or NSAIDs) and supportive care (fluid therapy, seizure control) improves survival rates. Delayed treatment often results in irreversible neuronal damage, chronic paresis, or fatal outcome.
Monitoring includes daily neurological examinations, temperature checks, and reassessment of blood work. Serial PCR testing confirms pathogen clearance, while repeat imaging assesses resolution of cerebral lesions. Rehabilitation may be necessary for dogs with residual gait abnormalities or muscle weakness.