Roles of ticks in the occurrence of emerging and re-emerging vector-borne viruses of zoonotic importance in West Africa

Ticks are arthropod vectors that transmit a wide range of emerging and re-emerging vector-borne diseases (VBDs), many of which are of considerable zoonotic importance. Recently, tick-borne diseases (TBDs), particularly those caused by arboviruses, have emerged as a significant public health concern in West Africa. The complex socio-ecological landscape in West Africa contributes to the circulation of several tick-borne arboviruses (TBAs), including Crimean-Congo hemorrhagic fever virus (CCHFV) and Dugbe virus (DUGV), both members of the genus Orthonairovirus, as well as other tick-borne flaviviruses such as Alkhurma hemorrhagic fever virus (AHFV). These pathogens, transmitted primarily by ixodid and argasid ticks, have been linked to hemorrhagic fevers, febrile illnesses, and encephalitis in both humans and animals. The biological adaptations of ticks, such as transovarial and transstadial transmission, co-feeding, and prolonged host associations, enhance their vector competence and persistence across generations. This review examines epidemiology, host-vector dynamics, life cycles, ecology, dispersal mechanisms and factors affecting ticks and the distribution of tick-borne viruses in West Africa. We also examined the ecological and socio-economic drivers that influence tick populations and virus transmission dynamics, such as climate variability, livestock movement, and deforestation. Notably, surveillance gaps, diagnostic challenges, and limited integration of tick ecology into disease control strategies remain major constraints to effective prevention and response against the occurrence, sustenance, and spread of tick-borne diseases. We therefore propose a coordinated One Health approach integrating epidemiological surveillance, vector control, and targeted community education with enhanced laboratory infrastructure and cross-sectoral collaboration.