Viral protein involved in the evasion of host innate defense by inhibiting the MAVS protein. During viral replication, dsRNA is produced and detected by DDX58/RIG-I or IFIH1/MDA5 that will activate MAVS to coordinate pathways leading to induction of antiviral cytokines. Several viral proteins including NS3/4A from Hepatitis C, or protease 3C from hepatitis A virus, cleave MAVS to abrogate its activity.