How does an encephalitis tick manifest after a bite? - briefly
Initial signs appear 7–14 days after the bite and include fever, headache, and muscle pain. Progression may involve nausea, vomiting, confusion, stiff neck, or seizures, indicating central nervous system involvement.
How does an encephalitis tick manifest after a bite? - in detail
A bite from a tick infected with the tick‑borne encephalitis virus introduces the pathogen into the dermis. The entry point may show a small, erythematous papule; swelling and mild pain are common, but a pronounced local reaction is not typical.
The incubation interval ranges from five to fourteen days, occasionally extending to twenty‑eight days. During this silent phase the virus replicates in the regional lymph nodes before spreading hematogenously.
The initial clinical stage is systemic. Fever often exceeds 38 °C, accompanied by chills, fatigue, headache, and muscle aches. Nausea, vomiting, and mild abdominal discomfort may appear. Some patients report photophobia or mild neck stiffness at this point.
After a brief remission, a second phase develops in up to 60 % of cases. Neurological manifestations include:
- Meningeal irritation: neck rigidity, positive Kernig/Brudzinski signs.
- Encephalitic signs: confusion, disorientation, delirium, seizures.
- Cerebellar involvement: ataxia, dysmetria, tremor.
- Cranial nerve deficits: facial weakness, diplopia.
- Myelitis or radiculitis in severe cases, leading to motor weakness or sensory loss.
Cerebrospinal fluid analysis typically reveals lymphocytic pleocytosis (100–500 cells/µL), elevated protein (0.8–2.0 g/L), and normal glucose. Serology shows TBE‑specific IgM within the first week of neurological onset, followed by IgG conversion. PCR detection of viral RNA in blood or CSF is possible but less sensitive after the first week.
Complications may include respiratory insufficiency, profound paresis, and long‑term sequelae such as persistent cognitive deficits, gait disturbance, or hearing loss. Mortality varies by age and disease severity, reaching up to 2 % in younger adults and 20 % in older patients.
Therapeutic measures are supportive: antipyretics, analgesics, careful fluid management, and monitoring of neurological status. No antiviral drug has proven efficacy; intensive care may be required for respiratory or cardiac compromise. Prevention relies on vaccination of at‑risk populations and avoidance of tick exposure through protective clothing and repellents.