Transmission potential of Culex and Aedes species for Madariaga virus, a member of the eastern equine encephalitis virus complex

Carvalho-Leandro, D. d.; Ferreira, F. C.; Santos, N. F.; Sames, W. J.; Tian, Y.; Ndeffo-Mbah, M. L.; Costa, E. A.; Turell, M. J.; Hamer, G. L.; Magalhaes, T.

doi:10.1101/2025.09.02.673670

bioRxiv · 10.1101/2025.09.02.673670

Transmission potential of Culex and Aedes species for Madariaga virus, a member of the eastern equine encephalitis virus complex

Carvalho-Leandro, D. d.·Ferreira, F. C.·Santos, N. F.·Sames, W. J.·Tian, Y.·Ndeffo-Mbah, M. L.·Costa, E. A.·Turell, M. J.·Hamer, G. L.·Magalhaes, T.

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Abstract

Madariaga virus (MADV), widely distributed in Latin America, can cause severe disease in humans and equids, yet, key aspects of its transmission cycle remain unclear. To identify mosquitoes that could act as MADV vectors, we assessed the vector competence of Aedes aegypti, Ae. albopictus, Ae. taeniorhynchus, Culex tarsalis, Cx. coronator, and Cx. quinquefasciatus, following oral exposure to MADV isolated in Panama (all species) or Brazil (Ae. taeniorhynchus only). MADV RNA and infectious virus were quantified from mosquito bodies, legs, and saliva. At 14 days post-exposure, five species had virus in all biological sample types. Culex quinquefasciatus was susceptible to infection and dissemination but had no positive saliva samples. Aedes taeniorhynchus showed higher infection probabilities with MADV-BR. Time-course analysis revealed distinct dynamics in Ae. aegypti and Ae. albopictus. Our findings indicate MADV may be compatible with mosquito species present in endemic regions and areas at risk of virus introduction.

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Carvalho-Leandro, D. d., Ferreira, F. C., Santos, N. F., Sames, W. J., Tian, Y., Ndeffo-Mbah, M. L., Costa, E. A., Turell, M. J., Hamer, G. L., Magalhaes, T.. 2025-09-04. Transmission potential of Culex and Aedes species for Madariaga virus, a member of the eastern equine encephalitis virus complex. https://doi.org/10.1101/2025.09.02.673670

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