IFNA1 and Japanese encephalitis: Vero cell lines are deficient in the synthesis of interferon alpha and beta (IFN α/β) – host immune defence molecules aimed at restricting viral replication, and a wide range of arthropod-borne viruses including strains of dengue types 1–4, West Nile, Japanese encephalitis, Usutu [57, 58] and ZIKV [41] replicate and elicit CPE in Vero cells.