Tick-borne encephalitis among US travellers, 2010-20

Area of Science:

• Medical Entomology
• Infectious Diseases
• Neurology

Background:

• Tick-borne encephalitis (TBE) is a significant arboviral disease prevalent in Europe and Asia.
• TBE cases in US travelers are rare, with limited documented instances prior to 2021.
• A TBE vaccine became available in the USA in August 2021, highlighting the need for updated traveler risk assessment.

Purpose of the Study:

• To review diagnostic testing for TBE at the CDC from 2010-2020.
• To analyze demographics, clinical presentations, and risk factors of TBE cases in US travelers.
• To inform pre-travel health counseling for individuals visiting TBE-endemic areas.

Main Methods:

• Retrospective review of TBE diagnostic testing at the CDC from 2010-2020.
• Data collection on confirmed TBE cases, including patient demographics and travel history.
• Analysis of clinical symptoms and reported risk factors, such as tick bites and outdoor activities.

Main Results:

• Six civilian US travelers were diagnosed with TBE between 2010 and 2020.
• Affected travelers included both pediatric and adult males who visited Europe or Russia.
• Reported activities included hiking and camping; two cases had a known tick bite, and symptoms included meningitis or encephalitis.

Conclusions:

• TBE cases among US travelers are infrequent but warrant clinical consideration.
• Pre-travel counseling should emphasize TBE risk reduction strategies and vaccine availability.
• Clinicians should suspect TBE in patients with neurological or febrile illnesses after returning from endemic regions.