Newly Recognized Hantaviruses Associated with Hantavirus Pulmonary Syndrome in Northern Brazil: Partial Genetic Characterization of Viruses and Serologic Implication of Likely Reservoirs

Following the occurrence of the first laboratory-confirmed cases of hantavirus pulmonary syndrome (HPS) in Maranhao State, Brazil, rodents were trapped and rodent materials screened by ELISA for antibodies to Sin Nom-bre and Andes hantaviruses. Antibody-positive samples were tested by RT-PCR, amplified products were se-quenced, and phylogenetic trees were constructed for comparison with known hantaviruses. From 104 rodent blood samples collected (40 Bolomys lasiurus, 52 Holochilus sciureus, 12 Oligoryzomys fornesi, and one Proechimys guyan-nensis), 21 (20.2%) were antibody-positive (one B. lasiurus, five O. fornesi, and 15 H. sciureus). Hantavirus RNA was amplified by PCR from two o. fornesi and four H. sciureus. Viral sequencing identified two hantavirus geno-types. The genotype recovered from o. fornesi, is designated herein as Anajatuba (ANA]) and the genotype re-covered from H. sciureus is designated Rio Mearim (RIME). Phylogenetic analysis of a 643-nucleotide region of the N segment showed both viruses to be most closely related (94-96 % nucleotide homology) to Rio Mamore virus, a virus associated with Oligoryzomys micro tis in Bolivia and Peru, but not found in northern Brazil. O. fornesi was frequently captured in and around human dwellings. H. sciureus, is a semi-aquatic rodent captured only in remote areas rarely frequented by humans. Key Words: Hantaviruses-HPS-Anajatuba virus-Oligoryzomys for-nesi-Rio Mearim virus-Holochilus sciureus-Phylogenetic characterization-Brazil. Vector-Borne Zoonotic Dis. 5,11-19. negative-stranded RNA segments. The large (L), medium (M), and small (5) segments are re-sponsible for encoding the viral polymerase, the G1 and G2 glycoproteins of the envelope, and the nucleocapsid protein, respectively (Schmaljohn 1996). Hantaviruses are hosted i