IFNA1 and encephalitis: It is noteworthy that AAN-I-IFN have been found also in an extremely rare case of encephalitis following infection by Powassan virus (POWV), another tick-borne orthoflavivirus (103), suggesting a more general role of AAN-I-IFN in the development of encephalitis triggered by these tick-borne orthoflaviruses (Fig. 1).