Tick-borne diseases: a severe health threat

Along with Lyme borreliosis, tick-borne encephalitis is the most common tick-borne disease in Europe.¹ 

Borreliosis is caused by bacteria transmitted to humans through the tick bite. The disease is most frequent in Europe but also occurs in North America and Asia.² There is no vaccine against borreliosis but most infections can be treated effectively with antibiotics.² 

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system which, in the majority of cases, also results from the bite of an infected tick.³ Every year, about 10,000-12,000 cases are reported but actual numbers are assumed to be much higher.³ In contrast to borreliosis, an effective vaccination is available against TBE.

Although Crimean-Congo haemorrhagic fever (CCHF) is rare in Europe, cases have been reported in in the Balkan and Mediterranean regions.⁴ CCHF is a life-threatening tick-borne disease caused by a virus that can also spread from human to human via contaminated blood. According to the World Health Organization (WHO), CCHF is currently one of the most important infectious diseases with pandemic potential and is therefore included in the WHO priorities for research and product development.⁵

Furthermore, climate change is contributing to the spread of tick-borne diseases by permitting expansion of tick habitats due to warming average temperatures. This increases the risk of such diseases in previously less affected areas.⁶

^{1 ECDC: Key messages about tick-borne encephalitis and tick-borne diseases – as of January 2025
2 ECDC: Factsheet about Borreliosis – as of January 2025 (last update: March 2016)
3 WHO: Tick-borne encephalitis – as of February 2025
4 ECDC: Crimean-Congo haemorrhagic fever – as of March 2025
5 ECDC: Factsheet for health professionals about Crimean-Congo haemorrhagic fever – as of March 2025 (last update: December 2023)
6 CDC: Vector-Borne Diseases – as of March 2025 (last update: March 2024)}