IFIH1 and viral infectious disease: We have recently reported the loss of the IFIH1/MDA5-dependent response to double-stranded RNA in pangolins [24], leading us to put forward the hypothesis that a diminished innate immune response to certain RNA viruses, including coronaviruses, may avoid overshooting host defense reactions and loss of IFIH1 may have allowed for the evolution of tolerance as a strategy to survive viral infections.