Probable vector of Crimean-Congo hemorrhagic fever virus; Hyalomma aegyptium: a systematic review and meta-analysis.

Introduction: Crimean-Congo hemorrhagic fever (CCHF) is the widest emerging severe viral tick-borne disease affecting humans. Crimean-Congo haemorrhagic fever virus (CCHFV) circulates by routine enzootic tick-vertebrate hosts-tick transmission cycles. We aimed to evaluate the molecular prevalence of CCHFV in ticks on a global scale.

Methods: A systematic procedure was used to perform this review and meta-analysis using PubMed, Google Scholar, and Web of Science databases from 1 January 2000 through 12 April 2023. Of the 2310 papers identified, 43 articles met the inclusion criteria for this study.

Results: The overall prevalence of CCHFV was 4.0% (95%CI: 2.7-6.0%) in ticks on the global scale, with heterogeneity (I²=96.387; p=0.0001). The genus Hyalomma was shown as the most frequent tick infected with CCHFV 5.4% (95%CI: 3.3-8.7%). We found that the pooled prevalence of CCHFV was higher in Hyalomma aegyptium 27.6% (95%CI: 22.7-33.2%). The pooled prevalence was higher in Asia 5.1% (95%CI: 3.3-7.7%), and Spain 21.0% (95%CI: 3.4-66.9). The locations with annual rainfall of 401-1000 mm 6.1% (95%CI: 2.6-13.5%) and latitude of 31-40° 6.0% (95%CI: 4.1-8.9%) were associated with the greatest pooled prevalence of CCHFV in ticks.

Conclusions: Surveillance of CCHFV in ticks will give a better comprehension for the future implementation of public health interventions. The question of whether Hyalomma aegyptium is a plausible or certain vector should be the subject of further investigation.