New World (NW) hemorrhagic fever (HF) arenaviruses are a group of rodent-borne zoonotic pathogens that cause severe disease with high case fatality rates upon transmission into human populations. These agents belong to clades B and D of the genus Mammarenavirus, family Arenaviridae, and include Junín virus (JUNV), Machupo virus (MACV), Guanarito virus (GTOV), Chapare virus (CHPV), Sabiá virus (SABV), and Whitewater Arroyo virus (WWAV). The GP1 subcomponent of the New World arenavirus GP is a primary target of the neutralizing antibody response, which has been shown to be effective in the prevention and treatment of infection.