Endemic Arenaviruses in Latin America

New World (NW) arenaviruses, including Guanarito virus (Mammarenavirus guanaritoense) (GTOV), Sabia virus (Mammarenavirus brazilense) (SBAV), Machupo virus (Mammarenavirus machupoense) (MACV), Chapare virus (Mammarenavirus chapareense) (CHAPV), and Junin virus (Mammarenavirus juninense) (JUNV), are a group of segmented negative-sense RNA viruses belonging to the family Arenaviridae, endemic in South America. These viruses have zoonotic origins and are primarily transmitted through contact with infected rodents. Person-to-person transmission, although less frequent, can occur in nosocomial settings. The spectrum of infections caused by these pathogens varies, ranging from self-limited febrile illnesses to severe hemorrhagic fever, with each virus presenting unique clinical characteristics. The emergence of these hemorrhagic fevers caused by NW arenaviruses can be traced back to the late 1950s in South America. These viruses have coexisted with their natural hosts, NW rodents, for millions of years. Their transition into infectious agents in humans coincided with environmental changes and shifts in agricultural practices, leading to explosive increases in host rodent populations. This chapter provides a comprehensive review of the epidemiology, pathology, clinical manifestations, and therapeutic approaches associated with the most prevalent NW arenaviruses, including GTOV, SBAV, MACV, CHAPV, and JUNV. Understanding the characteristics of these viruses and their impact on human health is crucial for developing effective prevention and treatment strategies