STAT2 and viral infectious disease: Compared to the commonly used A129, Ifnar-/-, or the AG129 mice as models of viral infections, in which either the type I interferon (A129 and Ifnar-/- mice) or both type I and type II interferon receptors are knocked out (AG129 mice), STAT2 KO hamsters are only partially defective in type I interferon signaling, thus they are less immunocompromised than the above-mentioned mouse models.