Eretmapodites mosquitoes are potential bridge vectors for arboviruses in western Côte d’Ivoire

Background Mosquito-borne arboviral diseases pose an increasing threat to public health. Many of them emerge from spillover events of arboviruses originating from enzoonotic cycles within primary rainforests, where they are maintained. Transmission to humans occurs through bridge vectors – mosquito species that feed on both animals and humans. One potential source of new or re-emerging arboviruses is the Taï National Park in Côte d’Ivoire, one of the largest remaining areas of primary rainforest in West Africa. This study aims to identify mosquito species in the Taï National Park with the potential to act as a bridge vector, facilitating the spillover of arboviruses to human populations. Methods From December 2021 to September 2022, we sampled mosquitoes in three zones: the primary rainforest of Taï National Park (sylvatic zone), the edge at Pauléoula village (transition zone) and the town of Taï near the park (urban zone). To collect mosquitoes, we used four box gravid traps and four CO ₂ -baited light traps. We conducted sampling over 120 days, resulting in 160 trap-days per trap type and zone. Results Across all zones, we collected 4,603 mosquito specimens (3,589 females and 1,014 males), belonging to 29 species. Species richness was highest in the urban zone ( n  = 22), followed by the sylvatic zone ( n  = 20) and the transition zone ( n  = 14). However, mosquito abundance was greatest in the sylvatic zone ( n  = 2,192), followed by the urban zone ( n  = 1,226) and transition zone ( n  = 1,185). Among the species that were frequent and present in more than one zone, we identified three vector species: Aedes aegypti, Eretmapodites fraseri and Eretmapodites quinquevittatus , with Er. fraseri being the most abundant. Conclusion Eretmapodites fraseri is a predominant mosquito species in the Taï National Park and may serve as an important bridge vector for new or re-emerging arboviruses. As the next step, we will screen our samples for arboviruses using metagenomics approaches. Additionally, we will further investigate the potential role of Er. fraseri as a vector species in arbovirus transmission.