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 Nombre and Andes hantaviruses. Antibody-positive samples were tested by RT-PCR, amplified products were sequenced, 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 guyannensis), 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 genotypes. The genotype recovered from O. fornesi, is designated herein as Anajatuba (ANAJ) and the genotype recovered 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 Río Mamoré virus, a virus associated with Oligoryzomys microtis 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.

Epidemia de febre do Oropouche em Serra Pelada, município de Curionópolis, Pará, 1994 / Fever epidemic of Oropouche virus in Serra Pelada, municipality of Curionópolis, Pará State, 1994

In the final of November 1994, an outbreak of a febrile disease was observed in the Serra Pelada gold mine (5 degrees 35'S: 49 degrees 30'W) in the Southeast region of Pará State. Twenty samples were collected and sent to the laboratory of Arbovirus of Instituto Evandro Chagas. The tests showed that the disease was caused by Oropouche virus (Bunyaviridae, Bunyavirus, Simbu serological group). Between 8-22 December 296 serum samples were taken (54 from febrile patients, 16 paired samples and 242 from contacts and convalescent patients) of the 73 familiar groups. From febrile patients, ten Oropouche virus strains were obtained. From paired serum, six seroconversions were obtained and 242 other Oropouche infections were diagnosed by HI and MAC ELISA. The clinical-picture of febrile disease accompanied by severe bedache, chills, myalgia, photophobia retrobulbar pain and malaise was observed. Involvement of central nervous system was not observed. Based on the serological data, we estimated that in the outbreak of Serra Pelada around 5,000 cases occurred corresponding to a prevalence of 83 per cent.