Summary
Definition
History and exam
Key diagnostic factors
- presence of risk factors
- fever
- fatigue
- general malaise
- headache
- body pains
- nausea
- mild meningitis
- severe encephalitis
- altered mental state
Other diagnostic factors
- cranial and spinal nerve palsies
- vestibular/hearing defects
- seizures
- paresis
- arms, shoulders, and head muscles paralysis
Risk factors
- history of recent tick bite
- summer months
- occupational exposure
- outdoors activities
- recent consumption of raw (unpasteurised) milk or dairy products
- age ≥45 years
- bioterrorism
Diagnostic investigations
1st investigations to order
- FBC
- erythrocyte sedimentation rate
- CRP
- LFTs
- CT brain
- cerebrospinal fluid analysis
- cerebrospinal fluid/serum serology
Investigations to consider
- cerebrospinal fluid/serum reverse-transcription polymerase chain reaction
- MRI head
- EEG
Treatment algorithm
suspected viral aetiology
confirmed TBE
Contributors
Authors
Ashley M. Croft, MA, MBBS, MSc, DTM&H, FFPHM

School of Pharmacy and Biomedical Science
University of Portsmouth
Portsmouth
UK
Disclosures
AMC declares that he has no competing interests.
Peer reviewers
John Williams, MRCP, DTM&H, DipHIVMed
Consultant Infectious Diseases Physician
The James Cook University Hospital
Middlesbrough
UK
Disclosures
JW declares that he has no competing interests.
Charlie Easmon, MBBS, MRCP, MSc Public Health, DTM&H, DOccMed
Medical Director
Your Excellent Health Service
Honorary Lecturer
UCL
London
UK
Disclosures
CE runs a private travel clinic.
References
Key articles
Taba P, Schmutzhard E, Forsberg P, et al. EAN consensus review on prevention, diagnosis and management of tick-borne encephalitis. Eur J Neurol. 2017 Oct;24(10):1214-e61. Abstract
UK Health Security Agency. Tick-borne encephalitis: epidemiology, diagnosis and prevention. Apr 2023 [internet publication].Full text
World Health Organization. Tick-borne encephalitis. 2025 [internet publication].Full text
Centers for Disease Control and Prevention. Tickborne diseases of the United States. May 2024 [internet publication].Full text
Reference articles
A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
Differentials
- Aseptic meningitis
- Encephalopathy (toxic/metabolic)
- Status epilepticus
More DifferentialsGuidelines
- Tick-borne diseases of the United States
- CDC Yellow Book: health information for international travel - tick-borne encephalitis
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