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This study aimed to analyse changes in the spatial distribution of Lutzomyia longipalpis in Posadas, an urban area located in northeastern Argentina. Data were obtained during the summer of 2007 and 2009 through two entomological surveys of peridomiciles distributed around the city. The abundance distribution pattern for 2009 was computed and compared with the previous pattern obtained in 2007, when the first human visceral leishmaniasis cases were reported in the city. Vector abundance was also examined in relation to micro and macrohabitat characteristics. In 2007 and 2009, Lu. longipalpis was distributed among 41.5% and 31% of the households in the study area, respectively. In both years, the abundance rates at most of the trapping sites were below 30 Lu. longipalpis per trap per night; however, for areas exhibiting 30-60 Lu. longipalpis and more than 60 Lu. longipalpis, the areas increased in both size and number from 2007-2009. Lu. longipalpis was more abundant in areas with a higher tree and bush cover (a macrohabitat characteristic) and in peridomiciles with accumulated unused material (a microhabitat characteristic). These results will help to prioritise and focus control efforts by defining which peridomiciles display a potentially high abundance of Lu. longipalpis.

The objective of this work was to evaluate the efficiency of an integrated program for the control of rodents in a shantytown of Buenos Aires City, Argentina. This program was developed in one year. During the preparation phase, an environmental survey of public spaces and dwellings was conducted in the test area to identify factors favoring the presence of rodents and to determine strategies and management measures to be implemented in the execution phase. Rodent abundance was monitored in the following four periods:(1) during the preparation phase, (2) during the execution phase, (3) immediately after the execution phase, and (4) 90 days after the end of the execution phase. According to the results of the preparation phase, we combined three different strategies to reduce rodent abundance in both dwellings and public spaces of the experimental area: rodenticide application, environmental sanitation in public spaces, and sanitary education.In this area the proportion of dwellings and public spaces with signs of rodent activity decreased significantly from the beginning of the trial to immediately after the end of the execution phase. There was a significant increase in rodent activity 90 days after the execution phase. This work reveals that although rodent infestation can be reduced in urban shantytowns, a long-term policy for sanitation improvement and sanitary education is required to keep rodent populations at safe levels for the community.

BackgroundUnderstanding the ecological processes that are involved in the transmission of zoonotic pathogens by small mammals may aid adequate and effective management measures. Few attempts have been made to analyze the ecological aspects that influence pathogen infection in small mammals in livestock production systems. We describe the infection of small mammals with Leptospira spp., Brucella spp., Trichinella spp. and Cysticercus fasciolaris and assess the related intrinsic and extrinsic factors in livestock production systems in central Argentina at the small mammal community, population and individual levels.Methodology/Principal findingsTen pig farms and eight dairy farms were studied by removal trapping of small mammals from 2008 to 2011. Each farm was sampled seasonally over the course of one year with cage and Sherman live traps. The 505 small mammals captured (14,359 trap-nights) included three introduced murine rodents, four native rodents and two opossums. Leptospira spp., anti-Brucella spp. antibodies and Trichinella spp. were found in the three murine rodents and both opossums. Rattus norvegicus was also infected with C. fasciolaris; Akodon azarae and Oligoryzomys flavescens with Leptospira spp.; anti-Brucella spp. antibodies were found in A. azarae. Two or more pathogens occurred simultaneously on 89% of the farms, and each pathogen was found on at least 50% of the farms. Pathogen infections increased with host abundance. Infection by Leptospira spp. also increased with precipitation and during warm seasons. The occurrence of anti-Brucella spp. antibodies was higher on dairy farms and during the winter and summer. The host abundances limit values, from which farms are expected to be free of the studied pathogens, are reported.Conclusions/SignificanceMurine rodents maintain pathogens within farms, whereas other native species are likely dispersing pathogens among farms. Hence, we recommend preventing and controlling murines in farm dwellings and isolating farms from their surroundings to avoid contact with other wild mammals.

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Summaryobjective To determine the prevalence of infection with hantaviruses in wild Rattus norvegicus and R. rattus populations in areas of Buenos Aires city. results Hantavirus seroprevalence was 11.9% in R. norvegicus (n = 151), varying between 0% and 26.1% depending on the site. Bigger sexually active males were more likely to be infected with Seoul virus than females or juvenile individuals. No antibody-reactive rodents were detected among 33 R. rattus analysed.conclusion Hantavirus infections are geographically widespread in Buenos Aires city and confirm that they have been enzootic there for at least 20 years.

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.