Lymphocytic Choriomeningitis Virus, Lassa Virus, and the South American Hemorrhagic Fevers (Arenaviruses)

Arenaviruses are transmitted by rodents and comprise several medically important pathogens that cause hemorrhagic fevers in humans. All arenaviruses can be divided based on their phylogenetic and antigenic relationships into Old World and New World virus complexes. The Old World complex includes arenaviruses that circulate worldwide and in Africa (i.e., lymphocytic choriomeningitis [LCMV] and Lassa [LASV] viruses). The New World complex includes viruses that circulate in South and North America (i.e., Junin [JUNV], Machupo [MACV], Guanarito [GTOV], and Sabia [SABV] viruses) and is further subdivided into three distinct clades designated as A, B, and C. The prototypic arenavirus LCMV has a worldwide distribution due to its association with Mus domesticus and Mus musculus and can cause febrile disease sometimes with central nervous system involvement as well as congenital infections. LASV is enzootic among rodents of the Murinae subfamily of the family Muridae inhabiting sub-Saharan Africa and is a causative agent of Lassa fever, a severe disease in humans. There are at least four pathogenic South American arenaviruses, JUNV, MACV, GTOV, and SABV, that are transmitted by rodents of the Sigmodontinae subfamily of the family Muridae and are known to cause hemorrhagic fever in humans in endemic areas of Argentina, Bolivia, Venezuela, and Brazil.