Despite the emerging threat of the Mayaro virus (MAYV) in Central and South-America, there are no licensed
antivirals or
vaccines available for this neglected mosquito-borne virus. Here, we optimized a robust
antiviral assay based on the inhibition of the cytopathogenic effect that could be used for high-throughput screening to identify MAYV inhibitors. We first evaluated different cell lines and virus inputs to determine the best conditions for a reliable and reproducible
antiviral assay. Next, we used this assay to evaluate a panel of
antiviral compounds with known activity against other arboviruses. Only three drugs were identified as inhibitors of MAYV: β-D-N4-hydroxycytidine (EIDD-1931),
favipiravir and
suramin. The in vitro anti-MAYV activity of these
antiviral compounds was further confirmed in a virus yield assay. These
antivirals can therefore serve as reference compounds for future anti-MAYV compound testing. In addition, it is of interest to further explore the activity of
EIDD-1931 and its orally bioavailable
pro-drug molnupiravir in animal
infection models to determine whether it offers promise for the treatment of MAYV
infection.