Screening Ticks for Crimean-Congo Hemorrhagic Fever Virus and Aigai Virus in Greece

Ixodid ticks are vectors for a plethora of pathogens, including the Crimean-Congo hemorrhagic fever virus (CCHFV), which causes severe disease in humans. Two autochthonous CCHF human cases were reported in 2025 in Greece. The aim of the present study was to gain a better insight into the geographic distribution and prevalence of CCHFV and the related Aigai virus (AIGV) in ticks in Greece. Therefore, 680 ticks (135 Hyalomma and 545 Rhipicephalus ticks) collected during 2024 from livestock (sheep, goats, cattle) and from the environment were tested for CCHFV and AIGV. AIGV was detected in 12 adult Rhipicephalus bursa ticks (12/511, 2.3%), while all Hyalomma ticks and R. bursa nymphs were negative for both viruses. AIGV-positive ticks were collected in May and June from goats and sheep in two distantly located regional units of Greece. AIGV sequences from partial S RNA segment differ from the prototype AIGV strain (AP-92) by 10.3% and 1.4% at the nucleotide and amino acid level, respectively. Integrated surveillance studies are needed in ticks, humans, wild and domestic animals within a One Health framework to gain a better insight into the epidemiology of CCHF in Greece, while clinical research is needed to elucidate the impact of AIGV in public health.