Alphaviruses, including Mayaro virus (MAYV) and Chikungunya virus (CHIKV), pose a growing public health threat, with increasing reports worldwide and no licensed antiviral treatments available. This study evaluated the antiviral activity of pyridine-3-carbohydrazide (P-3-C) against MAYV (strains BeAr and TRVL) and CHIKV (strain La Reunion, LR). Vero E6 or U-2OS cells were infected and treated with P-3-C for 24 h, and cell viab...