Geographic Distribution and Genetic Diversity of Whitewater Arroyo Virus in the Southwestern United States

ResearchThe virus family Arenaviridae comprises two serocomplexes.The lymphocytic choriomeningitis-Lassa (Old World) complex includes lymphocytic choriomeningitis (LCM), Lassa, Mopeia, Mobala, and Ippy viruses.The Tacaribe (New World) complex includes Tamiami (TAM), Whitewater Arroyo (WWA), Pichindé (PIC), Amapari, Flexal, Guanarito, Junin, Latino, Machupo, Oliveros, Parana, Pirital, Sabiá, and Tacaribe viruses.The arenaviruses have bipartite, single-stranded RNA genomes (1).The large (L) genomic segment encodes the viral RNA-dependent RNA polymerase and a zinc-binding protein.The small (S) genomic segment encodes the nucleocapsid (N) protein and glycoprotein precursor.The most comprehensive knowledge of the phylogeny of the family Arenaviridae is based on a fragment of the N protein gene (2-4).Six arenaviruses are known to cause severe disease in humans.LCM virus is an agent of acute central nervous system disease (5) and congenital malformations (6).Lassa, Junin, Machupo, Guanarito, and Sabiá viruses are etiologic agents of hemorrhagic fever in western Africa, Argentina, Bolivia, Venezuela, and Brazil, respectively (7).The arenaviruses known to occur in North America are LCM, TAM, and WWA.LCM virus was introduced into the Americas along with its principal rodent host, Mus musculus (house mouse) (8).TAM virus is known only from Sigmodon hispidus (hispid cotton rat) in southern Florida (9-11).WWA virus was originally recovered from Neotoma albigula (whitethroated woodrat) collected from northwestern New Mexico (12).In a recent study (13), antibody to an arenavirus was found in five Neotoma species in the southwestern United States: N. albigula in Arizona, Colorado, and New Mexico; N. stephensi (Stephen's woodrat) in Arizona and New Mexico; N. mexicana (Mexican woodrat) in Arizona and Utah; and N. fuscipes (dusky-footed woodrat) and N. lepida (desert woodrat) in California.The purpose of the present study was to extend our knowledge of the geographic distribution and genetic diversity of the arenavirus(es) associated with Neotoma rodents in the southwestern United States.