Ticks infected with Crimean-Congo hemorrhagic fever virus (CCHFV): A decision approach systematic review and meta-analysis regarding their role as vectors

Background: There are many studies present in literature performed to isolate CCHFV from ticks. However, gaps in knowledge for estimating global annual CCHFV infection rates; global CCHFV infection rates and records; CCHFV infection trend in ticks and ticks infested animals; and lack a decision regarding the role of ticks as CCHFV vectors caused to conduct this review. Methods: From 605 papers identified, 150 papers were selected to become the study meta-analysis (57 papers), detailed CCHFV infected ticks (63 papers), and systematic review (99 papers) parts. Results: Since there are no significant differences between the annual tick CCHFV infection rates; tick CCHFV infection rates between continents; and CCHFV infection rates between tick species and gender of ticks, and ticks and tick species infested animals. Given that ticks are considered both as CCHFV reservoirs and vectors. It is possible a little burden of CCHFV in infected ticks in natural enzootic cycles to maintain and disseminate CCHFV in humans. The decision regarding the role of ticks as CCHFV vectors administrated based on the study and a separately literature search regarding the role of ticks as CCHFV vectors; CCHFV infection rates and records; and trend of CCHFV infection records in 31 tick species. The trend of CCHFV infection records in 31 tick species exhibited a decreasing trend indicating the degree and importance of their roles as CCHFV vectors. Conclusions: Among 31 CCHFV infected tick species, 15 species have been enrolled as proven vectors and 16 species are suspected as potential vectors.

Automated summary

This study conducted a review on the global annual CCHFV infection rates, CCHFV infection trend in ticks and ticks infested animals, and the role of ticks as CCHFV vectors. The results showed no significant differences in infection rates among different tick species and genders, and between ticks and tick-infested animals. Ticks are considered both as reservoirs and vectors for CCHFV, playing a key role in maintaining and disseminating the virus in natural enzootic cycles.