A Family of RNA Viruses naturally infecting Rodents and consisting of one genus (Arenavirus) with two groups: Old World Arenaviruses (Arenaviruses, Old World) and New World Arenaviruses (Arenaviruses, New World). Infection in Rodents is persistent and silent. Vertical transmission is through Milk-, Saliva-, or urine-borne routes. Horizontal transmission to Humans, Monkeys, and other Animals is important.