Vector competence of temperate and tropical mosquito species for Babanki virus

Babanki virus (BBKV), an alphavirus belonging to the Western Equine Encephalitis antigenic complex, was first isolated from Mansonia africana mosquitoes in 1969 but remains poorly characterized. Transmitted to humans and animals through the bite of an infectious female mosquito, it is associated with febrile illness, rash, and arthritis, similarly to its close relative Sindbis virus. No specific treatment or vaccine is currently available. Here, we experimentally assessed the vector competence of mosquito species from tropical and temperate regions under ecologically relevant temperature conditions. Using a BBKV molecular clone, individual midguts, salivary glands, legs, and saliva samples were collected at different time points to assess infection, dissemination, and transmission dynamics in Aedes (Aedes albopictus from Nice and Réunion Island, and Aedes aegypti) and Culex (Culex pipiens molestus from Paris and Culex quinquefasciatus) mosquitoes. We show that BBKV efficiently infects and disseminates in all tested species, with Aedes mosquitoes exhibiting higher infection rates (>70%) compared to Culex species. Importantly, infectious viral particles were detected in mosquito saliva, confirming transmission potential. Viral replication persisted over time and was supported by both RNA quantification and infectious virus titration. Overall, our results show that multiple mosquito species from both temperate and tropical regions are competent vectors for BBKV, highlighting a significant emergence potential.