Epizootiology of Tacaribe serocomplex viruses (Arenaviridae) associated with neotomine rodents (Cricetidae, Neotominae) in southern California.

The objective of this study was to advance our knowledge of the epizootiology of Bear Canyon virus and other Tacaribe serocomplex viruses (Arenaviridae) associated with wild rodents in California. Antibody (immunoglobulin G [IgG]) to a Tacaribe serocomplex virus was found in 145 (3.6%) of 3977 neotomine rodents (Cricetidae: Neotominae) captured in six counties in southern California. The majority (122 or 84.1%) of the 145 antibody-positive rodents were big-eared woodrats (Neotoma macrotis) or California mice (Peromyscus californicus). The 23 other antibody-positive rodents included a white-throated woodrat (N. albigula), desert woodrat (N. lepida), Bryant's woodrats (N. bryanti), brush mice (P. boylii), cactus mice (P. eremicus), and deer mice (P. maniculatus). Analyses of viral nucleocapsid protein gene sequence data indicated that Bear Canyon virus is associated with N. macrotis and/or P. californicus in Santa Barbara County, Los Angeles County, Orange County, and western Riverside County. Together, analyses of field data and antibody prevalence data indicated that N. macrotis is the principal host of Bear Canyon virus. Last, the analyses of viral nucleocapsid protein gene sequence data suggested that the Tacaribe serocomplex virus associated with N. albigula and N. lepida in eastern Riverside County represents a novel species (tentatively named "Palo Verde virus") in the genus Arenavirus.

GENETIC VARIATION IN MULTILOCUS MICROSATELLITE GENOTYPES IN TWO SPECIES OF WOODRATS (NEOTOMA MACROTIS AND N. FUSCIPES) FROM CALIFORNIA.

Five microsatellite loci were used to develop multilocus genotypes for Neotoma macrotis (n = 128) and N. fuscipes (n = 29). Several statistical analyses were used to estimate genetic structure, levels of genetic variability, and degree of relatedness within groups of these 2 species. Samples of N. macrotis represented 2 groups and 4 population clusters throughout southern California. Samples of N. fuscipes represented 2 regions in northern and southern California. Genetic structure was detected among samples of N. macrotis and N. fuscipes at a regional level. Both species displayed moderate to high genetic diversity in terms of mean expected heterozygosity (0.939 and 0.804 for N. macrotis and N. fuscipes, respectively) and mean polymorphic information content (0.930 and 0.761 for N. macrotis and N. fuscipes, respectively). Mean relatedness values within regions and populations of N. macrotis indicated 4th-order levels of relatedness within groups (e.g., distant-cousin relationships). Mean relatedness values within regions of N. fuscipes indicated 2nd-order (e.g., half-sibling) relationships within the northern region and 3rd-order (e.g., cousin) relationships in the southern region. One locus in particular (Nma04) was determined to be diagnostic in distinguishing between these 2 species.

Principal host relationships and evolutionary history of the North American arenaviruses.

A previous study suggested that the genomes of the arenaviruses native to North America are a product of genetic recombination between New World arenaviruses with significantly different phylogenetic histories. The purpose of this study was to extend our knowledge of the principal host relationships and evolutionary history of the North American arenaviruses. The results of this study suggest that the large-eared woodrat (Neotoma macrotis) is a principal host of Bear Canyon virus and that the present-day association of Bear Canyon virus with the California mouse (Peromyscus californicus) in southern California represents a successful host-jumping event from the large-eared woodrat to the California mouse. Together, the results of analyses of viral gene sequence data in this study and our knowledge of the phylogeography of the rodents that serve as principal hosts of the New World arenaviruses suggest that genetic recombination between arenaviruses with significantly different phylogenetic histories did not play a role in the evolution of the North American arenaviruses.