If a tick bite occurs, how long before encephalitis signs appear and what are the symptoms? - briefly
Encephalitis usually emerges 1–3 weeks after a tick bite, with possible onset as early as a few days or as late as a month. Early manifestations comprise fever, headache, neck stiffness, confusion or seizures, followed by altered consciousness and focal neurological deficits.
If a tick bite occurs, how long before encephalitis signs appear and what are the symptoms? - in detail
Tick‑borne encephalitis (TBE) develops after a bite from an infected ixodid tick. The incubation period typically ranges from seven to fourteen days, but cases have been reported as early as three days and as late as twenty‑one days after exposure. The window of symptom onset is therefore most often within the second week following the bite.
The disease progresses through three phases, each with characteristic clinical features:
• First (prodromal) phase – abrupt fever, fatigue, headache, myalgia, and occasional nausea. Symptoms resemble a mild viral infection and last one to five days before remission.
• Second (asymptomatic) phase – a brief period of apparent recovery lasting two to seven days. No overt signs occur, but viral replication continues in the central nervous system.
• Third (neurological) phase – manifestation of encephalitic involvement. Common signs include: – High fever persisting beyond the prodrome. – Severe headache, often described as frontal or occipital. – Neck stiffness and photophobia. – Altered mental status ranging from confusion to coma. – Focal neurological deficits such as ataxia, tremor, or paresis. – Nausea, vomiting, and occasional seizures. – In children, irritability and lethargy may predominate.
Laboratory findings typically reveal pleocytosis in cerebrospinal fluid, elevated protein, and, in later stages, specific IgM antibodies against TBE virus. Early recognition of the temporal relationship between tick exposure and the onset of neurological signs is essential for prompt supportive care and, when available, antiviral therapy.