Factores ecoambientales relacionados con potenciales reservorios de Leptospira spp. en la Reserva Ecológica Costanera Sur, Buenos Aires, Argentina

Las modificaciones ambientales generan entornos de interfaz en los que la transmisión de Leptospira spp. puede verse afectada. Con el objetivo de identificar y analizar variables ecoambientales asociadas a potenciales reservorios de Leptospira spp. en la Reserva Ecológica Costanera Sur (RECS) (Buenos Aires, Argentina) y áreas urbanizadas contiguas, se realizó un muestreo por conveniencia en líneas transectas, estratificado y proporcionado. Fueron capturados 170 mamíferos de 11 especies y se analizó la presencia de Leptospira spp. por serología, cultivo y PCR. En áreas conservadas, se registraron mayormente Didelphis albiventris y Deltamys kempi, mientras que el Oligoryzomys flavescens también fue hallado en áreas degradadas, y la Rattus norvegicus solo fue encontrada en áreas degradadas. No se detectó Leptospira spp. en los mamíferos silvestres. Un perro sin tenedor responsable resultó positivo por ser0ología. Las condiciones ambientales de la RECS sugieren un ecosistema poco propicio para Rattus, evidenciando la importancia de la conservación de áreas naturales en entornos urbanos.

Non-volant small mammals (Rodentia and Didelphimorphia) diversity in an isolated area of the Serra da Mantiqueira, Minas Gerais state, Brazil

The southeastern Atlantic Forest of the Zona da Mata Mineira is located in the extreme north of Minas Gerais state, Brazil. The Serra da Mantiqueira, is a mountainous region with a high diversity of small non-volant mammal species, several of which are rare species or endemic lineages. The presence of cryptic species in small mammals makes the karyotype an excellent tool for identification and detection of new lineages. We analyzed the karyotype of 14 species: 11 rodents – Abrawayaomys ruschii, Akodon cursor, Blarinomys breviceps, Delomys sublineatus, Juliomys ossitenuis, Oligoryzomys nigripes, Oligoryzomys flavescens, Oxymycterus dasytrichus, Rhipidomys tribei, Sooretamys angouya, and Thaptomys nigrita; and three marsupials – Monodelphis scalops, Philander quica, and Marmosops incanus. We described for the first time the fundamental autosomal number and the morphology of sex chromosomes of Abrawayaomys ruschii, a rare sigmodontine species, and described a new karyotype for Blarinomys. The revision of published karyotypes of the species herein studied enabled the expansion of the geographic distribution of Oligoryzomys nigripes and Delomys sublineatus.

Ixodes spp. (Acari: Ixodidae) ticks in Rio Grande do Sul state, Brazil

Among the 251 described species of ticks from the genus Ixodes, only eight were previously reported in Brazil, Ixodes amarali, Ixodes aragaoi, Ixodes auritulus, Ixodes fuscipes, Ixodes loricatus, Ixodes luciae, Ixodes paranaensis and Ixodes schulzei. Of those species, I. loricatus is considered commonly found, whereas I. auritulus and I. aragaoi were registered just one time in Rio Grande do Sul (RS) state, Southern Brazil. This paper aims to update the Ixodes species occurring in RS through the investigation of the ixodofauna of small rodents. Data from 314 wild rodents were analyzed from nine municipalities of Pampa biome and five from the Atlantic Rainforest in RS. Rodents belonging to the following species were infested by Ixodes spp. ticks: Akodon azarae, Akodon montensis, Akodon paranaensis, Akodon reigi, Calomys laucha, Delomys dorsalis, Deltamys kempi, Holochilus brasiliensis, Oligoryzomys flavescens, Oligoryzomys nigripes, Oxymycterus nasutus, Scapteromys tumidus (Cricetidae) and Cavia aperea (Caviidae). The tick identification was performed based on morphological dichotomous keys, their updates and by molecular techniques. Considering the ticks from the rodents and those collected directly from the environment, 34 specimens of Ixodes spp. were collected. Our results improved to five the list of Ixodes species that occur in RS: I. loricatus, I. auritulus, I. aragaoi, I. fuscipes and I. longiscutatus. Moreover, the finding of I. longiscutatus increases to nine the number of Ixodes species in Brazil. The occurrence of two species of the Ixodes ricinus complex (I. aragaoi and I. fuscipes) highlights the potential impact of Ixodes spp. ticks on public health.

To the systematics of the subgenus Hesperomyobia Bochkov, 1997 (Acariformes: Myobiidae: Radfordia)

A new myobiid mite species Radfordia (Hesperomyobia) akodon sp. nov. is described from Akodon varius Thomas (Rodentia: Cricetidae: Sigmodontinae) from Bolivia. This new species is known only from a female which differs from those of Radfordia (H.) sigmodontis Radford from Sigmodon hispidus Ray and Ord, and Radfordia (H.) sigmomys Bochkov and Fain from Sigmodon alstoni (Thomas) by the following features. In R. (H.) akodon sp. nov., setae vi are 50 μm long and 7 μm wide (vs. 10–12 μm long and 2 μm wide in R. sigmodontis, and 23–25 μm long and 2 μm wide in R. sigmomys), dorsal idiosomal setae si, se, c1, c2, d1, and d2 are 5–10 μm wide (vs. 2–3 μm wide in R. sigmodontis and R. sigmomys), and setae e1 are 2.6 times longer than f1 (vs. subequal in R. sigmodontis and R. sigmomys). In addition, Radfordia (Hesperomyobia) vandenberghi Fain and Lukoschus is newly recorded herein from Oligoryzomys flavescens (Waterhouse) and Oligoryzomys sp. (Rodentia: Cricetidae: Sigmodontinae) in Bolivia. It is suggested that this mite species is associated exclusively with hosts of the genus Oligoryzomys Bangs.