RAF1 and infection: –55 Notably, just as DTV MN-PV320 acquired these NS3, NS4a, and NS5 substitutions during nonlethal infection, there were changes in viral diversity in the brains of these survivors similar to that observed in DTV NY21-027. It is also possible that these substitutions may not impact replicative fitness but could, instead, alter host immune activation, which can influence disease severity. Of note, the untranslated regions at the 5′ and 3′ end of the POWV genome were not included but are also known to influence transmissibility, immune evasion, and viral replication.56