The effects of particular viral proteins on STAT1 and STAT2 tyrosine phosphorylation differed, with measles V protein having no effect on IFN-I-induced tyrosine phosphorylation of either STAT and phlebovirus NSPs of Heartland virus (HRTV) and severe fever with thrombocytopenia syndrome virus (SFTSV) showing inhibitory activity with respect to phosphorylation of STAT2, specifically. The gene discussed is STAT1; the disease is Fever.