How does the encephalitis tick affect humans? - briefly
The encephalitis‑carrying tick transmits viruses such as Powassan and tick‑borne encephalitis, producing inflammation of the brain and meninges. Clinical presentation includes fever, severe headache, neck rigidity, and possible neurological deficits, while prompt antiviral therapy and supportive care reduce disease severity.
How does the encephalitis tick affect humans? - in detail
The encephalitis tick serves as the primary vector for the tick‑borne encephalitis (TBE) virus, a flavivirus transmitted during prolonged blood meals. Virus particles enter the host’s bloodstream, disseminate to regional lymph nodes, and cross the blood‑brain barrier after an incubation period of 7–14 days. Clinical presentation follows three sequential phases.
The initial phase manifests as nonspecific febrile illness: high temperature, headache, myalgia, and malaise. Laboratory findings often reveal mild leukocytosis and elevated C‑reactive protein. Symptoms resolve spontaneously in approximately one‑third of cases, but the virus may persist in the central nervous system.
The second, neurologic phase occurs in 30–40 % of infected individuals. Typical signs include:
- Severe headache and neck stiffness
- Photophobia and altered mental status
- Focal neurological deficits (e.g., facial palsy, ataxia)
- Seizures in severe cases
Cerebrospinal fluid analysis shows pleocytosis with lymphocytic predominance, elevated protein, and normal glucose. Magnetic resonance imaging may demonstrate hyperintense lesions in the thalamus, basal ganglia, or brainstem.
The third phase, when present, involves long‑term sequelae. Persistent deficits comprise:
- Cognitive impairment (memory loss, reduced concentration)
- Motor dysfunction (tremor, gait instability)
- Chronic fatigue and mood disorders
Recovery can be incomplete; up to 10 % of patients retain some neurological impairment after one year.
Risk factors for severe disease include advanced age, lack of prior vaccination, and exposure to infected tick habitats (forests, grasslands). Children and immunocompromised individuals exhibit higher rates of neurologic involvement.
Prevention relies on vaccination, personal protective measures (long sleeves, tick repellents), and prompt tick removal. Early diagnosis, supported by serologic testing for specific IgM and IgG antibodies, enables timely supportive care, which remains the main therapeutic approach because antiviral agents are ineffective against the virus.
«Vaccination against TBE reduces the incidence of neurologic disease by more than 95 %», according to the European Centre for Disease Prevention and Control, underscoring the public‑health importance of immunization programs in endemic regions.