Key message 1: Ticks can carry disease
Ticks are abundant in woodlands all across Europe from early spring to late autumn. They live by sucking blood from animals and occasionally bite humans.
Ticks themselves do not cause disease but if a tick is infected with a virus or bacterium, then that pathogen can be transmitted through the tick’s bite and cause disease in humans.
There are two common tick-borne diseases in Europe:
- Tick-borne encephalitis (TBE): The TBE virus can infect the brain and cause tick-borne encephalitis (brain inflammation). About one in four people infected with the TBE virus fall ill and develop symptoms of encephalitis which include high fever, severe headache, and sometimes paralysis and convulsions. Most patients with TBE encephalitis will recover but up to one third will suffer long-term complications of the disease.
There is no specific treatment for TBE once you are infected but there is an effective vaccine that prevents infection.
- Lyme borreliosis is caused by a bacterium, the spirochete Borrelia burgdorferi, which lives in the stomach of ticks and can be transmitted when humans are bitten by infected ticks.
The clinical presentation of borrelia infection ranges from no symptoms at all to a characteristic skin rash called ‘erythema migrans’ and meningitis with neurological symptoms.
Lyme borreliosis is effectively treated and cured with antibiotics.
There are other much more rare tick-borne diseases in Europe of which two are of importance:
- Crimean Congo haemorrhagic fever (CCHF) is a viral infection that causes severe disease with bleeding in humans. The disease is present in Africa and the Middle-East. Occasionally, small numbers of cases are reported from Albania, Bulgaria, Kosovo, and Turkey. The first case in Greece was reported in 2008.
Humans are infected through the bite of an infected tick or by contact with infected blood or other tissue from infected animals or humans. People who work with livestock and other animals are most at risk of CCHF.
- Tick-borne relapsing fever (TBRF) is a tick-borne disease that is rare in Europe. Like Lyme borreliosis, it is caused by a spirochete of the genus Borrelia and can be treated with antibiotics. The ticks that carry the spirochetes that cause TBRF are found on the Iberian Peninsula and in Asia Minor. Most cases reported in Europe are imported from parts of the world where the disease is more common.