How dangerous is tick-borne encephalitis for humans? - briefly
Tick-borne encephalitis can cause severe neurological disease, with case‑fatality rates of 1–5% and long‑term neurological deficits in up to 30% of survivors. Effective vaccination lowers incidence, yet untreated infection remains a significant health threat.
How dangerous is tick-borne encephalitis for humans? - in detail
Tick‑borne encephalitis (TBE) is a viral infection transmitted by Ixodes ticks, prevalent in forested regions of Europe and Asia. Annual incidence ranges from a few hundred cases in low‑risk areas to several thousand in endemic zones such as the Baltic states, Central Europe, and parts of Russia. The disease exhibits a biphasic course: an initial febrile phase lasting 2–7 days, followed by a neurologic phase in 20–30 % of patients.
Neurologic manifestations include meningitis, encephalitis, and myelitis. Meningitis presents with headache, neck stiffness, and photophobia; encephalitis adds altered consciousness, seizures, and focal deficits; myelitis can cause paralysis and sensory loss. Severe forms may lead to permanent neurological sequelae—cognitive impairment, ataxia, or motor dysfunction—in up to 10 % of symptomatic cases. Reported case‑fatality rates vary by viral subtype: the European subtype shows 0.5–2 % mortality, while the Siberian subtype reaches 5–10 %.
Risk factors for severe disease encompass older age, immunosuppression, and lack of prior immunity. Children often experience milder illness, but long‑term neurocognitive effects have been documented. The incubation period averages 7–14 days, allowing a window for post‑exposure prophylaxis with immunoglobulin in rare circumstances, though routine use is not recommended.
Prevention relies on vaccination, which provides >95 % seroconversion after a primary series of three doses. Booster doses are advised every 3–5 years depending on age and exposure risk. Additional measures include avoiding tick habitats during peak activity (April–October), wearing protective clothing, and performing thorough body checks after outdoor activities. Prompt removal of attached ticks reduces transmission probability, as virus transmission typically requires ≥24 hours of attachment.
Therapeutic options are limited to supportive care; no specific antiviral drug is approved. Management includes analgesia, antipyretics, and, when indicated, corticosteroids to reduce cerebral edema. Rehabilitation services improve outcomes for patients with residual deficits.
In summary, TBE poses a moderate to high health threat in endemic regions, with a measurable mortality risk and a substantial burden of permanent neurological impairment among survivors. Vaccination and rigorous tick‑avoidance strategies remain the most effective means of reducing individual and public health impact.