The sigmodontine South American rodent genus Oligoryzomys was first described as a subgenus of the genus Oryzomys to group together species distinguished by morphological measurements. To describe the dispersion patterns of this genus in South America, in this study, a total of 100 sequences were analyzed and compared with sequences of 9 Oligoryzomys species from GenBank. The sequences comprised 90 mitochondrial cytochrome b genes and 10 nuclear interphotoreceptor retinoid-binding protein genes, from 75 individuals of 7 species from 27 localities. Topologies of different phylogenetic trees revealed Oligoryzomys as a monophyletic genus containing 2 main species groups, one designated as the "Amazon-Cerrado" assemblage and the second as the "Pampa-Andean" clade. The north-to-south geographic pattern observed supports the hypothesis that the genus started from the northern Andes, occupied the Amazon and the Cerrado, and later inhabited the more southern regions of South America.

In this study, the geographic patterns of genetic variation of three rodent species belonging to the tribe Oryzomyini were investigated using the mitochondrial cytochrome b and nuclear IRBP genes in biomes that are undergoing degradation processes to a greater or lesser degree. The samples are from 25 collecting localities distributed throughout the Amazon, Cerrado, Atlantic Forest, and Pampa biomes. The results show that the three species have a population and geographic structure, besides being in demographic equilibrium. The phylogenetic analyses performed on Euryoryzomys russatus and Hylaeamys megacephalus showed these specimens grouped in three distinct clades forming geographic gradients (North-South direction in H. megacephalus). Intraspecific genetic divergence was higher in H. megacephalus (4.53%), followed by E. russatus (1.79%), and lowest in Sooretamys angouya (0.88%). The results obtained indicate that, necessarily, the management strategies to preserve genetic diversity should be different for each species, since each of them presented specific population parameters.

SUMMARYHantavirus cardiopulmonary syndrome (HCPS) is an infectious disease caused by hantaviruses of the family Bunyaviridae, and is transmitted by aerosols of excreta of infected rodents. The aim of the present study was to determine antibody levels to hantavirus in the population that lives at frontier of Brazil and Argentina. Participated of the study 405 individuals living in the municipalities of Bandeirante, Santa Helena, Princesa and Tunapolis, state of Santa Catarina, Brazil. IgG antibodies to hantavirus were analyzed in sera by an ELISA that uses a recombinant N protein of Araraquara hantavirus as antigen. The results were also confirmed by immunofluorescent test. Eight individuals showed antibodies to hantavirus (1.97% positivity), with serum titers ranging from 100 to 800. Six seropositives were males, older than 30 years and farmers. Our results reinforce previous data on hantavirus circulation and human infections in the southern border of Brazil with Argentina.

No abstract

Submetido em 20/11/2012 Aceito para publicação em 02/10/2013 ResumoO grau de ameaça e a importância ecológica dos mamíferos terrestres evidenciam a necessidade da constante realização de pesquisas com o intuito de acrescentar informações ao conhecimento atual sobre esse tema. Este estudo teve por objetivo fornecer uma lista de espécies de mamíferos terrestres em um remanescente de Mata Atlântica localizado no sudoeste do estado do Paraná. A riqueza de espécies e a frequência de ocorrência foram estudadas de abril a outubro de 2009, utilizando dois métodos: observação direta e registro de vestígios. Foram registrados 20 táxons distribuídos em sete ordens: Artiodactyla, Carnivora, Didelphimorphia, Lagomorpha, Primates, Rodentia e Xenarthra. Dentre estes, quatro táxons foram registrados tanto por observação direta quanto pelo registro de vestígios e os demais foram registrados somente por meio de vestígios. As espécies com ocorrência mais frequente foram Didelphis sp. (30,6%) e Cerdocyon thous (25,6%). Dos 20 táxons registrados, Leopardus pardalis, Leopardus tigrinus e Cuniculus paca constam como vulneráveis no Livro Vermelho da Fauna Ameaçada no Estado do Paraná. Apesar de pequena, a área de estudo deve auxiliar na disponibilidade de alimento e abrigo para a mastofauna, representando um importante elemento da paisagem regional.