The virucidal activity of Cb AEs is mediated by enzymatic degradation of the viral lipidic envelope. (A) Lipase enzymatic activity of Cb AE-1, Cb AE-2 and Cb AE-1-S187G measured via an egg yolk agar plate assay. (B, C) Analysis of the exposure of DENV (B) or ZIKV (C) genomic RNA. DENV or ZIKV was first treated with serial concentrations of Cb AE-1, Cb AE-2 or BSA and then with RNase-A. Viral RNA degradation was evaluated by RT-qPCR. (D, E) The S187G mutant of Cb AE-1 fully lost its ability to suppress DENV (D) and ZIKV (E) infection: inhibition curves of Cb AE-1 and Cb AE-1-S187G against DENV (D) or ZIKV(E). Serial concentrations of Cb AE-1 or Cb AE-1-S187G were mixed with 50 pfu of DENV or ZIKV in VP-SFM medium to perform standard plaque reduction neutralization tests (PRNTs). (F) Representative negative stained transmission electron microscopy images of ZIKV particles treated with 10 µg/ml BSA (arrow head) and those treated with 10 µg/ml Cb AE-1 (empty arrow head); high magnification: 120,000×, low magnification: 30,000×. (G, H) Rate of DENV (G) or ZIKV (H) replication inhibition following exposure to Cb AEs before viral infection of Vero cell monolayers. The viral genome was quantified by RT-qPCR. (B, C, G, H) Significance was determined using unpaired t-tests. Data are presented as the mean ± SEM.