SummaryIn this study, we identified hantavirus genotypes and their reservoirs and evaluated the spatial and temporal distribution of the virus in rodent population in three protected areas of Argentina over 3 years (2007)(2008)(2009)(2010). A total of 837 rodents were captured with an effort of 22 117 trap-nights. We detected the genotype Lechiguanas in Oligoryzomys nigripes and O. flavescens and Pergamino in Akodon azarae.There was no correlation between seroprevalence and trap success of the host. The proportion of seropositive males was significantly higher than the proportion of seropositive females. The total length of seropositives was higher than that of seronegatives in each host species. Seropositive individuals were observed in warm months and not in cold months, which suggests an infection cycle. This investigation confirms that protected areas of central east Argentina are places with a variety of sylvan rodents species associated with different hantavirus genotypes where reservoirs are numerically dominant. Although there was more than one known reservoir of hantavirus, only one species had antibodies in each area. This can be explained because the transmission of the virus does need not only the presence of a rodent species but also a threshold density. Longevity of even a small proportion of the host population in cold months may provide a trans-seasonal mechanism for virus persistence. The seroprevalence detected was higher than the one found before in rodent populations of Argentina, and this explains the appearance of human cases in two of these three areas.

The aim of this research was to compare the abundance, growth, age structure and reproductive patterns of Rattus norvegicus and Mus musculus populations of a shanty town and a parkland in the city of Buenos Aires, Argentina. Live trapping of rodents was conducted in each area every 2 months, from September 2006 to August 2007. Abundance of R. norvegicus and M. musculus was significantly higher in the shanty town than in the parkland. Abundance of both species showed significant differences between trapping sessions in both study sites. Both species showed a peak in abundance in summer in the parkland and also in autumn in the shanty town. Age structure of both species differed between summer-autumn and winter-spring in the shanty town. In the parkland, pregnant females of both species were only found in spring-summer. No significant differences were found in any of the reproductive parameters compared between the shanty town and the parkland. Our results suggest that the shanty town represents a favourable but not constant habitat for rodents throughout the year.

We captured 3 hantavirus rodent hosts in Otamendi Natural Reserve, Argentina, during 2007–2012. Hantavirus antibodies were found only in Akodon azarae grass mice, mainly in males and old animals. Higher abundance of this species was associated with warm and rainy weather and high water levels, which peaked after a strong El Niño event.

Hantavirus pulmonary syndrome (HPS) is a severe zoonotic disease caused by hantaviruses hosted in various rodents species. In Argentina, its transmission to humans has been associated to exposure during activities such as farming, recreation, and tourism which are carried out in wild and rural areas. The aim of this study was to analyze the macro- and micro-habitat use and spatio-temporal variation of small sylvan rodents in Pre Delta and Islas de Santa Fe national parks, located in an HPS-endemic area of Argentina. Rodent communities were studied at six sites: two islands, a riparian forest, an inland forest, a marsh, and the margins of a pond. A total of 453 individuals of five species were captured with a trapping effort of 9471 trap-nights. Maximum species richness was found at the marsh and the pond margin sites. Abundance of rodents was influenced by flooding events. Two hantavirus reservoirs, Oligoryzomys flavescens and Akodon azarae, were identified in the area. O. flavescens was captured in every habitat, but it was dominant in Islas de Santa Fe National Park where its abundance was strongly influenced by flooding. A. azarae was captured in every habitat except on the islands. A. azarae behaved as a generalist species at a micro-habitat scale in every habitat of Pre Delta National Park except for the marsh where it selected patches with low vegetation height. Based on these results, several disease prevention measures, including the use of rodent-proof containers for food, and keeping the grass short in the camp site, are proposed in order to reduce the risk to visitors and residents of contracting HPS.