Tick-Borne Encephalitis (Forest Encephalitis)

Forest (tick-borne) encephalitis is an acute viral disease first identified in eastern USSR forests (May-Aug 1934), also called Russian spring-summer encephalitis. Wild rodents are reservoirs; ticks are vectors. Clinical: abrupt high fever, meningeal signs, altered consciousness, paralysis; abnormal CSF; frequent sequelae.

Common Symptoms

Irregular fever; involuntary movement; apathy; dementia; fatigue; low fever; nausea; remittent fever

Causes and Pathogenesis

Togaviridae, Flavivirus, TBE virus (far-eastern subtype); neurotropic, 30-40 nm icosahedron, +ssRNA ~4×10^6 Da, 218S. Envelope glycoprotein E (hemagglutinating/neutralizing antigen) mediates adsorption/entry; Arg changes alter tropism/virulence (Tyr384→His attenuates; His392→Tyr enhances). M/C proteins; 7 nonstructural proteins. Cold-resistant (months at -20°C, 1 year in 50% glycerol at 0°C); heat/disinfectant-sensitive (60°C/10 min, boiling instant; 3% cresol/20 min, 0.5% formalin/48 h). Isolates from brain; infectious RNA after phenol/ether. Grows in chick embryo/yolk sac/CAM/human embryo kidney/mouse embryo/pig kidney/sheep embryo/Hela/BHK-21. Antibodies: HI at day 5-7 peak 2-4 weeks; CFT at day 10-14 peak 1-2 months; neutralizing persists years. Western/Central European TBE (CETE) is a subtype (I. ricinus vector, milder). Pathogenesis: tick bite → E-protein receptor fusion → local node/mononuclear phagocyte replication → viremia at day 3-7 → brain capillaries → neurons. Outcome depends on inoculum and host immunity. Pathology: widespread gray/white matter and meninges; severe cervical spinal cord/brainstem/midbrain/basal ganglia (vs JE); inflammatory exudates, hemorrhages, perivascular lymphocyte cuffs, neuronal necrosis, gliosis; liver/kidney/heart/lung exudative/degenerative changes.

Treatment

Drug therapy, supportive therapy

Preventive Measures

Strictly endemic. Before entering: sanitation, rodent/insect control. Vaccinate first-time entrants. Wear "five-tight" protective clothing; tuck cuffs/collar/ankles. Disinfect patient clothing. (1) Tick control. (2) Five-tight suit + high boots + head net; repellent dimethyl phthalate (200 g/suit, 10-day efficacy). (3) Vaccine: 2 mL then 3 mL 7-10 days apart before March; annual booster.

Department to Visit

It is recommended to visit the Infectious Diseases department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.