Tick-borne relapsing fever (TBRF) is a disease caused by several species of spiral-shaped bacteria (spirochaetes) that are transmitted to humans through the bite of infected soft ticks. At least six TBRF species are known to occur in Europe or close to its boundaries. The greatest endemic risk in Europe lies in the Iberian peninsula, particularly in the Mediterranean part.

The disease is characterised by relapsing or recurring episodes of fever, often accompanied by headache, muscle and joint aches and nausea. The number of relapses is highly variable and the interval between fever episodes ranges from four to 14 days. Reports of death are rare.

Recommended measures to prevent infection include avoiding tick-infested areas (especially during summer months), wearing long trousers and tucking trouser legs into socks, using tick repellents, and using bed nets when sleeping on the ground or camping.