Immature mosquitoes from groundwater habitats in a temperate wetland of Argentina: Environmental associations and seasonal variation of community attributes

We studied the seasonal patterns of 3 community attributes (breeding site index, richness, and diversity) of groundwater mosquito immatures and their associations with meso-and microhabitat factors in the Paran Lower Delta, Argentina, from December 2009 to November 2010. Monthly collections at 4 sites yielded 2,313 mosquito immatures, belonging to 19 species assigned to 6 genera. Immatures developed in a wide range of microenvironmental conditions (water temperature 4.030.2°C, pH 5.49.1, electrical conductivity 0.026.33 mS/cm, and dissolved oxygen 0235.6), and their occurrence was significantly associated with lower water temperature and dissolved oxygen values. Most frequently captured species were Culex dolosus s.l. (58.6), Aedes crinifer (22.9), and Cx. intrincatus (19.0). Breeding site index was highest in winter (0.76) and lowest in spring (0.54). Species richness and diversity varied significantly among seasons (peaking in summer), land uses, and habitat types.Fil: Cardo, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Unidad de Ecología de Reservorios y Vectores de Parásitos; ArgentinaFil: Vezzani, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Unidad de Ecología de Reservorios y Vectores de Parásitos; ArgentinaFil: Carbajo, Anibal Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Unidad de Ecología de Reservorios y Vectores de Parásitos; Argentin

Aedes aegypti spreading in South America: New coldest and southernmost records

The geographic distribution of Aedes (Stegomyia) aegypti (L.) in South America has been expanding during the last decades. Herein we present two new distribution records that extend its southern limits towards localities with extremer environmental conditions than reported to date. San Antonio Oeste constitutes the southernmost finding for the continent (40º44’S), whereas Tandil is the infested locality with the coldest mean annual temperature in Argentina (14.17ºC). The projection of a previous distribution model for Ae. aegypti predicts these two cities as positive and suggests several other localities with suitable conditions for vector proliferation beyond its assumed distribution limits.Fil: Rubio, Alejandra. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Cardo, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Vezzani, Dario. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto Multidisciplinario de Ecosistemas y Desarrollo Sustentable; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carbajo, Anibal Eduardo. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Assessment of Culex pipiens bioforms in the world’s southernmost distribution limit

The mosquito Culex pipiens s.s. L. occurs as two bioforms that differ in physiology and behaviour affecting virus transmission cycles. To assess the occurrence of Cx. pipiens bioforms in the southernmost limit of its distribution, specimens were collected aboveground in southern Buenos Aires Province and east Patagonia, Argentina. Ten larvae and 25 adults were individually processed and identified by polymerase chain reaction (PCR) amplification of Ace-2 and CQ11 loci. Culex quinquefasciatus Say (one larva, two adults), Cx. pipiens f. molestus (one larva, one adult) and one adult of hybrid origin were identified in Buenos Aires Province; only Cx. pipiens f. molestus was recorded in Patagonia (eight larvae, 21 adults). The potential absence of bioform pipiens and its implications in arbovirus enzootic cycles is discussed.Fil: Cardo, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Rubio, Alejandra. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Vezzani, Dario. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto Multidisciplinario de Ecosistemas y Desarrollo Sustentable; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Carbajo, Anibal Eduardo. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

An interdisciplinary approach to assess human health risk in an urban environment: A case study in temperate Argentina

Unplanned urbanization increases the exposure of people to environmental hazards. Within a landscape ecology framework, this study is a diagnosis of human health risk in San Martín, an urban district of Buenos Aires, Argentina. Risk was estimated by combining four hazard indexes (water and air pollution, and mosquito and rodent infestation) and a vulnerability index. Each index was obtained by integrating environmental and socio-demographic layers in a Geographic Information System. Spatial autocorrelation was assessed for each hazard, vulnerability and risk indexes using Moran's tests. Also, spatial associations between pairs of variables were addressed by means of Geographically Weighted Regressions. The robustness of hazard and vulnerability indexes was checked by a sensitivity analysis. In General San Martín district, 83.3% of the population is exposed to relatively high levels of at least one hazard; 7.4% is exposed to relatively high levels of all hazards (11.5% of the total area) and only 16.7% lives in areas of relatively low levels of all hazards (15.4% of the total area). Areas where hazard intensity was relatively high corresponded to those areas where the most vulnerable population lives, enhancing human health risk. The models for hazards and vulnerability were reasonably robust to changes in the weights of the variables considered. Our results highlight the spatially heterogeneous nature of human health risk in an urban landscape, and reveal the location of critical risk hotspots where reduction or mitigation actions should be focused.Fil: Morandeira, Natalia Soledad. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Castesana, Paula Soledad. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: Cardo, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Salomone, Vanesa Natalia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Vadell, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Rubio, Alejandra. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Assessment of Environmental Hazards to Public Health in Temperate Urban Argentina

Human health risk in urban areas depends on multiple environmental features. We performed a year-round survey in a highly urbanized district located in temperate Argentina (General San Martín, Buenos Aires) to establish baseline information about environmental hazards associated with health risks. Sampling was stratified into low and high hazardous zones according to estimated indexes previously developed for the area for four hazards: drinking water and air pollution, and mosquito and rodent infestation. Water from wells showed lower concentrations of aluminum, manganese and iron, and higher values of arsenic than tap samples, with the latter showing records above the maximum permitted for arsenic, aluminum and chromium. Benzene concentration in air was higher in summer than in winter, and in areas close to dumps and landfills, gas stations, high traffic pathways and industries with respect to low hazard areas. Adult mosquito collections were more abundant in high hazardous areas, three species from the genus Culex dominated the captures and the proportion of individuals from each species was variable seasonally and spatially. Rodent activity was recorded inside and outside dwellings, and its observed values did not differ between low and high hazardous areas. In the comparison between field data and estimated hazard maps, high accuracy was obtained for air pollution maps, intermediate accuracy for water pollution and mosquito infestation, and poor accuracy for rodent infestation. How to improve field surveys and estimated maps are both discussed, highlighting the need for dynamic feedback between GIS-based models and environmental monitoring.Fil: Vadell, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Salomone, Vanesa Natalia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Castesana, Paula Soledad. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Morandeira, Natalia Soledad. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rubio, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; ArgentinaFil: Cardo, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Is autumn the key for dengue epidemics in non endemic regions? The case of Argentina

Background. Dengue is a major and rapidly increasing public health problem. In Argentina, the southern extreme of its distribution in the Americas, epidemic transmission takes place during the warm season. Since its re-emergence in 1998 two major outbreaks have occurred, the biggest during 2016. To identify the environmental factors that trigger epidemic events, we analyzed the occurrence and magnitude of dengue outbreaks in time and space at different scales in association with climatic, geographic and demographic variables and number of cases in endemic neighboring countries. Methods. Information on dengue cases was obtained from dengue notifications reported in the National Health Surveillance System. The resulting database was analyzed by Generalized Linear Mixed Models (GLMM) under three methodological approaches to: identify in which years the most important outbreaks occurred in association with environmental variables and propose a risk estimation for future epidemics (temporal approach); characterize which variables explain the occurrence of local outbreaks through time (spatio-temporal approach); and select the environmental drivers of the geographical distribution of dengue positive districts during 2016 (spatial approach). Results. Within the temporal approach, the number of dengue cases country-wide between 2009 and 2016 was positively associated with the number of dengue cases in bordering endemic countries and negatively with the days necessary for transmission (DNT) during the previous autumn in the central region of the country. Annual epidemic intensity in the period between 1999-2016 was associated with DNT during previous autumn and winter. Regarding the spatio-temporal approach, dengue cases within a district were also associated with mild conditions in the previous autumn along with the number of dengue cases in neighboring countries. As for the spatial approach, the best model for the occurrence of two or more dengue cases per district included autumn minimum temperature and human population as fixed factors, and the province as a grouping variable. Explanatory power of all models was high, in the range 57-95%. Discussion. Given the epidemic nature of dengue in Argentina, virus pressure from endemic neighboring countries along with climatic conditions are crucial to explain disease dynamics. In the three methodological approaches, temperature conditions during autumn were best associated with dengue patterns. We propose that mild autumns represent an advantage for mosquito vector populations and that, in temperate regions, this advantage manifests as a larger egg bank from which the adult population will re-emerge in spring. This may constitute a valuable anticipating tool for high transmission risk events.Fil: Carbajo, Anibal Eduardo. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cardo, María Victoria. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guimarey, Pilar Consuelo. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Lizuain, Arturo Andrés. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Buyayisqui, María Pía. Ministerio de Salud de la Nación; ArgentinaFil: Varela, Teresa. Ministerio de Salud de la Nación; ArgentinaFil: Utgés, Maria E.. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Giovacchini, Carlos. Ministerio de Salud de la Nación; ArgentinaFil: Santini, Maria Soledad. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Estructura de las comunidades de mosquitos de cuerpos de agua en el suelo en el Bajo Delta del Río Paraná: un enfoque multiescalar considerando la heterogeneidad ambiental y las estrategias de oviposición

Los humedales son ecosistemas muy favorables para los insectos con estadios acuáticos, y dada su compleja dinámica del agua, son escenarios ideales para evaluar la influencia de las características ecofisiológicas de las especies en la estructuración de las comunidades en función del ambiente. En esta tesis, se investigó cómo se estructuran las comunidades de mosquitos (Diptera: Culicidae) que habitan en cuerpos de agua en el suelo (CAS) en función de la heterogeneidad ambiental a tres escalas espaciales de un humedal considerando sus efectos sobre distintas estrategias de oviposición. Entre los 1.689 CAS inspeccionados durante 2008- 2012 en el Bajo Delta del Río Paraná, se colectaron en total 10.626 inmaduros de mosquitos pertenecientes a 32 especies de siete géneros. Mediante el uso de modelos lineales generalizados y análisis de nicho se identificaron variaciones en la estructura de distintas comunidades en respuesta a la estacionalidad, a las características propias de los CAS, al uso de la tierra y al paisaje. Dichas respuestas dependieron de la estrategia de oviposición, siendo distintas las asociaciones entre la dinámica del agua (lluvia y mareas) y el uso de la tierra para mosquitos de inundación y de balsa. La composición del ensamble en CAS temporarios varió en función del paisaje, no así los otros atributos comunitarios; los patrones de recambio de especies estuvieron dominados por mosquitos de inundación. El conjunto de resultados sugiere que la heterogeneidad ambiental a distintas escalas espaciales afecta distintos atributos de las comunidades de mosquitos, y que las estrategias de oviposición tienen un rol central en dicha relación

Tire-breeding mosquitoes of public health importance along an urbanisation gradient in Buenos Aires, Argentina

Used vehicle tires are a source of mosquito vectors and a means of their introduction and expansion. With the aim of assessing the effects of urbanisation on the main mosquito vectors in temperate Argentina, the infestation levels of Aedes aegypti (L.) and Culex pipiens L. were studied in used tires from highly urbanised cities to low-urbanised small towns in Buenos Aires. Immatures of both species accounted for 96% of the 9,722 individuals collected; the total individuals collected represented seven species. The percentage of water-filled tires containing mosquitoes [container index (CI)] was 33% and the percentage of infested sites [site index (SI)] was 65.2%. These indexes decreased significantly from low to high urbanisation levels for both mosquito species. The relative abundance (RA) of Ae. aegypti immatures was slightly higher toward large cities, but showed no difference for Cx. pipiens. The CI of shaded tires was significantly higher than the CI of exposed tires for both mosquito species. There was no difference in RA values between shaded and sunlit tires. The CI and the SI were highest during the summer across the urbanisation levels, except for Cx. pipiens, which continued to increase during the autumn in small towns. Results related to urbanisation gradient, sunlit exposure and seasonality are discussed