Shifts in mosquito communities from diversity to dominance of potential arbovirus bridge vectors in the urban forest parks within arboviral foci in Abidjan, Côte d’Ivoire

Urban forest parks can offer a nature-based solution for carbon sequestration, climate change mitigation, well-being, leisure and education, but can harbour mosquitoes, including arbovirus vectors. The effects of ecozones on the species composition of mosquitoes and host-seeking behaviours of potential arbovirus vectors were assessed in three forest parks located within arboviral foci in Abidjan, Côte d’Ivoire. Mosquitoes and larval containers were sampled among urban and sylvatic ecozones, from January to September 2024. Collections yielded 8034 mosquitoes distributed into 31 species, including two newly recorded species, Eretmapodites grenieri and Toxorhynchites separatus . Abundance was higher in the urban ecozones, while species richness was twice as high in the sylvatic ecozones. Aedes aegypti dominated in all ecozones, but displayed higher abundance in the urban ecozones. Conversely, the newly established Aedes albopictus and several sylvan species were preponderant in the sylvatic ecozones. Larvae colonised mostly artificial containers in the urban ecozones, while unexpectedly occurring equitably in artificial and natural containers in the sylvatic ecozones. Aedes aegypti and Culex quinquefasiatus females were mostly seeking human hosts in the urban ecozones, whereas Ae . albopictus and Aedes dendrophilus were more aggressive in the sylvatic ecozones, and Aedes vittatus and Eretmapodites chrysogaster were biting indifferently among both ecozones. This study demonstrates that anthropophagic and zoophagic mosquito communities shift from diversity to dominance of key arbovirus vectors in the urban ecozones where females blood-feed abundantly on humans. Therefore, the urban-forest interface is an area of potential epidemiological importance requiring further investigation and should be prioritised for vector surveillance and control in the arboviral hotspots. Intersectoral vector control programmes, integrating public health, biodiversity conservation and ecotourism stakeholders, could reduce exposure of visitors and residents to arboviruses in the urban park environments.