Geographic distribution of Tick-borne encephalitis virus complex

Area of Science:

• Virology
• Epidemiology
• Public Health

Background:

• The geographic distribution of the tick-borne encephalitis virus (TBEV) complex is expanding.
• Increasing transboundary movement and serological cross-reactivity necessitate a comprehensive understanding of TBEV distribution.
• The TBEV complex includes TBE virus, Alkhurma haemorrhagic fever virus, Kyasanur forest disease virus, louping-ill virus, Omsk haemorrhagic fever virus, and Powassan virus.

Purpose of the Study:

• To identify the geographic distribution of the TBEV complex and associated viruses.
• To assess the risk of TBEV complex infection through seroprevalence studies.
• To inform diagnostic and control strategies by mapping TBEV distribution.

Main Methods:

• Systematic review of published reports using PubMed, EMBASE, and Cochrane library.
• Inclusion of TBEV complex case-related studies and seroprevalence studies.
• Analysis of surveillance data from endemic and non-endemic regions.

Main Results:

• National surveillance studies for TBEV were conducted in 20 countries across Europe and Asia.
• Human TBEV infections were reported in 14 additional countries.
• Seroprevalence studies identified TBEV complex infections in regions distant from the traditional TBEV belt, including Malaysia, Comoros, Djibouti, and Kenya.
• Specific viruses within the complex were reported in India, China, USA, Canada, Saudi Arabia, Egypt, UK, Ireland, and Siberia.
• Overlapping distributions of TBEV complex viruses with other pathogens were observed in several areas.

Conclusions:

• The geographic distribution of the TBEV complex is extensive and shows significant overlap with other viruses.
• Accurate serologic diagnosis requires awareness of potential cross-reactivity due to overlapping distributions.
• Knowledge of TBEV complex distribution patterns is crucial for implementing effective surveillance and control measures.