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.
Peer reviewer acknowledgements
BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.
Disclosures
Peer reviewer affiliations and disclosures pertain to the time of the review.
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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