Epidemiological patterns of Crimean-Congo hemorrhagic fever in Iran and its neighboring endemic high-risk territories: A systematic review.

This study synthesizes epidemiological, virological, and ecological data from Iran and its neighboring endemic countries between 2005 and 2025. Analysis of 55 included studies revealed that the disease disproportionately affects males aged 15-44, particularly livestock handlers, slaughterhouse workers, and housewives, with elevated incidence in border provinces during spring and summer. Hyalomma ticks were identified as the primary reservoirs and vectors, while domestic ruminants-sheep, goats, and cattle -were confirmed as served as amplifying hosts. Phylogenetic investigations highlighted the Asia 1 genotype (Clade IV) across all three nations. Case fatality rates varied regionally, ranging from 8% to 20% in Iran and escalating to 12%-40% in Iran's territories, reflecting disparities in healthcare access and outbreak management. Endemic transmission hubs were concentrated in interconnected border zones, driven by unregulated livestock trade and seasonal migration that facilitate bidirectional pathogen exchange. The findings underscore the role of ecological connectivity and socioeconomic practices in perpetuating CCHF's regional burden. This review provides a novel, integrated perspective on cross-border transmission dynamics, offering insights for targeted interventions. Addressing these gaps will be critical to curbing CCHF's impact high-risk regions.