Genetic identification and characterization of limestone canyon virus, a unique Peromyscus-borne hantavirus

Hantaviruses, family Bunyaviridae, are rodent-borne RNA viruses that can cause hantavirus pulmonary syndrome (HPS) in various regions of the Americas. A coevolutionary relationship exists between hantaviruses and their specific rodent reservoir hosts; the phylogeny of the viruses generally matches that of the rodents. There are several Peromyscus-borne hantaviruses, including Sin Nombre virus, the most common cause of HPS in North America. This report describes the genetic detection and characterization of a newly discovered Peromyscus boylii-borne virus, Limestone Canyon (LSC) virus, the most divergent member of the Peromyscus-borne hantaviruses to date. Analysis of a 1209-nucleotide region of the S segment of LSC virus showed it to be more closely related to hantaviruses found in harvest mice (Reithrodontomys megalotis and R. mexicanus) than to other Peromyscus-associated hantaviruses (Sin Nombre, New York, and Monongahela). Phylogenetic analysis of virtually the entire M genome segment (3489 nucleotides) of LSC virus revealed a similar picture in which LSC virus was found to be very distinct from other Peromyscus-associated viruses, but its exact relationship to the other Peromyscus-borne and the Reithrodontomys-borne viruses was not resolved. These results indicate that hantavirus host species-jumping events can occur by which a hantavirus may switch to, and become established in, a rodent host belonging to a different genus. P. boylii are present throughout the southwestern United States and central Mexico. More extensive screening of HPS patients by using RT-PCR assays will be necessary to determine if LSC virus can cause human disease.