Emergence and spread of Hyalomma ticks and Crimean-Congo haemorrhagic fever in Europe: a systematic review.

BACKGROUND: Crimean-Congo haemorrhagic fever (CCHF) is a severe, often fatal zoonotic disease caused by the CCHF virus (CCHFV). It is primarily transmitted by Hyalomma ticks, which serve as both reservoir and vector. While these ticks are endemic to Asia, Africa, and parts of Europe, recent detections in previously unaffected European regions raise concerns about the potential spread of the disease. OBJECTIVES: This study aims to systematically review the first detections of Hyalomma ticks, CCHFV, and CCHF disease in Europe. The goal is to support surveillance strategies and enhance preparedness for future outbreaks. METHODS: A systematic literature search was conducted across six international databases, complemented by targeted searches. From 1315 articles retrieved (1235 from systematic and 80 from targeted searches), 92 were included based on relevance to the presence of Hyalomma ticks, CCHFV, and/or CCHF in Europe. RESULTS: Hyalomma ticks are either endemic or have been detected at least once in 40 European countries. CCHFV and CCHF diseases have been reported in 24 and 22 countries, respectively. The distribution of Hyalomma ticks has expanded because of environmental and climatic changes, as well as increased movement of birds, livestock, and humans. CCHF has been present in Europe for decades, with early reports from Bulgaria, Russia, Ukraine, and Kosovo. More recent detections include Georgia, Spain, the UK, and Portugal. CONCLUSIONS: The ecological and climatic suitability for Hyalomma ticks is increasing across Europe, heightening the risk of CCHFV transmission. Integrated entomological surveillance and virological monitoring are essential for early detection and rapid response to potential outbreaks. Strengthening these efforts will be critical to containing the spread of CCHF and protecting public health.