Muju virus (MUV) is a zoonotic negative-sense single-stranded RNA virus of the genus Orthohantavirus. It is a member virus of Puumala orthohantavirus. It is one of four rodent-borne Hantaviruses found in the Republic of Korea. It is the etiologic agent for Hantavirus hemorrhagic fever with renal syndrome (HFRS). The other species responsible for HFRS in Korea are Seoul orthohantavirus, Hantaan orthohantavirus, and Soochong virus.