Filling the gaps in the Argentinian distribution of orthohantavirus: First finding of Lechiguanas virus in rodents from Corrientes, Argentina.

Hantavirus Pulmonary Syndrome (HPS) is an emerging infectious disease caused by orthohantaviruses in the Americas. In Argentina, since 1995, several reservoirs and virus variants have been described, but the northeastern and central endemic zones in the country include an area without human or rodent infections, despite sharing rodent species with areas with that disease. The aim of this study was to search for orthohantavirus in rodent communities that inhabit this area, which borders two endemic areas of HPS. Small rodents were captured in June of 2022 through a total effort of 644 trap nights distributed in five grids located in the Iberá National Park, Corrientes, Northeastern Argentina. All rodents were sexed, weighed, and the species was recorded. Blood samples were extracted to detect ANDV-specific immunoglobulin G (IgG), and to extract the RNA virus. Trimmed sequences were mapped against reference sequences from GenBank. We captured a total of 36 Oligoryzomys flavescens and 15 Oxymycterus rufus. We detected the O. flavescens species infected with Lechiguanas orthohantavirus in the camping area of the National Park. A nucleotide comparison with previously published sequences shows a 98.34% similarity to the virus obtained from a human case of HPS reported in the adjacent Misiones province. This study demonstrated, for the first time, that O. flavescens is a host of the Lechiguanas orthohantavirus in this zone and contributes to closing information gaps on the distribution of orthohantavirus in Argentina. Additionally, the high similarity with the hantavirus found in the human case of Misiones suggests that the reservoir in that province would also be O. flavescens (not previously confirmed). This information permits us to focus on the preventive measurements to protect the human population.

Pequenos mamiferos nao-voadores (Didelphimorphia, Rodentia) em campos litoraneos do extremo sul do Brasil

Non-volant small mammals are key elements in natural environments due its importance as food resource. This study aimed to investigate the species composition and habitat occupancy by non-volant small mammals (Didelphimorphia, Rodentia) in a coastal grassland area in southern Rio Grande do Sul coastal plain. Between April 2009 and March 2010 pitffal traps were used to capture small mammals in coastal grasslands associated to sand dunes and arbustive Restinga. We sampled 180 individuals including two marsupials (Cryptonanus guahybae and Didelphis albiventris) and seven rodent species (Calomys laucha, Cavia aperea, Ctenomys flamarioni, Deltamys kempi, Oligoryzomys flavescens, Oxymycterus nasutus and Scapteromys tumidus). Cryptonanus guahybae, D. albiventris and C. flamarioni were captured only in dunes while C. aperea and O. nasutus were recorded only in arbustive Restinga habitats. Calomys laucha, D. kempi, O. flavescens and O. nasutus were captured in both habitats. Oligoryzomys flavescens and C. laucha were the most representative species in both habitats, comprising respectively 40.7 and 38.9% of captures in dunes and 56.3 and 34.9% of captures in Restinga habitats. The species richness recorded in the sampled coastal grasslands area was lower than those previously recorded in subtropical forest coastal systems.

Pequenos mamíferos não-voadores são elementos chave em ambientes naturais devido a sua importância como recurso alimentar. Este estudo teve como objetivo investigar a composição de espécies e a ocupação de habitat por pequenos mamíferos não-voadores (Didelphimorphia, Rodentia) em uma área de campos litorâneos na região sul da planície costeira do Rio Grande do Sul. Entre abril de 2009 e março de 2010 armadilhas de interceptação e queda foram utilizadas para a captura de pequenos mamíferos em campos associados a dunas e a restinga arbustiva. Foram amostrados 180 indivíduos pertencentes a duas espécies de marsupiais (Cryptonanus guahybae e Didelphis albiventris) e sete espécies de roedores (Calomys laucha, Cavia aperea, Ctenomys flamarioni, Deltamys kempi, Oligoryzomys flavescens, Oxymycterus nasutus e Scapteromys tumidus). Cryptonanus guahybae, D. albiventris e C. flamarioni foram capturados somente em dunas, enquanto que C. aperea e O. nasutus foram registrados somente em restinga arbustiva. Calomys laucha, D. kempi, O. flavescens e O. nasutus foram capturados em ambos os ambientes. Oligoryzomys flavescens e C. laucha foram as espécies mais representativas em ambos os ambientes, compreendendo respectivamente 40,7 e 38,9% das capturas em dunas, e 56,3 e 34,9% das capturas em restinga. A riqueza de espécies registrada na área de campo litorâneo amostrada foi inferior a aquelas previamente registradas em sistemas florestais costeiros subtropicais.