Early Start to Tick-Borne Disease Season in Switzerland

Switzerland is experiencing an unusually early start to its tick-borne disease season in 2025, raising significant public health concerns across the nation. The Federal Office of Public Health (FOPH) has already reported six cases of tick-borne encephalitis, marking an unprecedented early-season occurrence not witnessed in the past twelve years.

The early emergence of tick-related health issues is directly linked to Switzerland's unusually mild winter, with temperatures consistently running 2 degrees above long-term averages. Scientific data confirms that ticks become active when temperatures reach 7 degrees Celsius, conditions that have occurred earlier this year. January 2025 alone saw 126 cases of Lyme disease, a significant increase from the 90 cases recorded in January 2024, demonstrating the immediate impact of warmer temperatures on disease transmission.

Two primary tick-borne diseases concern Swiss health authorities: tick-borne encephalitis (TBE) and Lyme borreliosis. While TBE can be prevented through vaccination, Lyme disease requires vigilant prevention and early detection. Lyme disease, caused by bacteria discovered by Willy Burgdorfer in 1980, typically presents with a characteristic rash and flu-like symptoms. Early antibiotic treatment is crucial for preventing long-term complications affecting the joints, heart, and nervous system.

Since 2019, Switzerland has taken proactive measures by including tick-borne encephalitis vaccination in basic health insurance coverage, making it accessible to all residents. This policy, recommended across nearly all of Switzerland, represents a significant step in public health protection. The healthcare system maintains vigilant monitoring of case numbers, with particular attention to the peak infection months of April through August.

Swiss health authorities strongly recommend preventive measures, including vaccination against TBE where appropriate, regular body checks after outdoor activities, and prompt medical consultation if symptoms appear. The public is advised to be particularly vigilant during the peak months of April through August, though this year's early onset demonstrates the need for year-round awareness. Those experiencing symptoms should seek medical attention immediately, especially given the importance of early treatment for Lyme disease.