63 research outputs found

    Carbon dioxide diffuse emission and thermal energy release from hydrothermal systems at Copahue-Caviahue Volcanic Complex (Argentina).

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    The north-western sector of Caviahue caldera (Argentina), close to the active volcanic system of Copahue, is characterized by the presence of several hydrothermal sites that host numerous fumarolic emissions, anomalous soil diffuse degassing of CO2 and hot soils. In March 2014, measurements of soil CO2 fluxes in 5 of these sites (namely, Las M\ue1quinas, Las Maquinitas I, Las Maquinitas II, Anfiteatro, and Termas de Copahue) allowed an estimation that ~165t of deeply derived CO2 is daily released. The gas source is likely related to a relatively shallow geothermal reservoir containing a single vapor phase as also suggested by both the geochemical data from the 3 deep wells drilled in the 1980s and gas geoindicators applied to the fumarolic discharges. Gas equilibria within the H-C-O gas system indicate the presence of a large, probably unique, single phase vapor zone at 200-210\ub0C feeding the hydrothermal manifestations of Las M\ue1quinas, Las Maquinitas I and II and Termas de Copahue. A natural thermal release of 107MW was computed by using CO2 as a tracer of the original vapor phase. The magmatic signature of the incondensable fumarolic gases, the wide expanse of the hydrothermal areas and the remarkable high amount of gas and heat released by fluid expulsion seem to be compatible with an active magmatic intrusion beneath this portion of the Caviahue caldera

    LABEC, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage

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    The LABEC laboratory, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage, located in the Scientific and Technological Campus of the University of Florence in Sesto Fiorentino, started its operational activities in 2004, after INFN decided in 2001 to provide our applied nuclear physics group with a large laboratory dedicated to applications of accelerator-related analytical techniques, based on a new 3 MV Tandetron accelerator. The new accelerator greatly improved the performance of existing Ion Beam Analysis (IBA) applications (for which we were using since the 1980s an old single-ended Van de Graaff accelerator) and in addition allowed to start a novel activity of Accelerator Mass Spectrometry (AMS), in particular for 14C dating. Switching between IBA and AMS operation became very easy and fast, which allowed us high flexibility in programming the activities, mainly focused on studies of cultural heritage and atmospheric aerosol composition, but including also applications to biology, geology, material science and forensics, ion implantation, tests of radiation damage to components, detector performance tests and low-energy nuclear physics. This paper describes the facilities presently available in the LABEC laboratory, their technical features and some success stories of recent applications

    Parasite spread at the domestic animal - wildlife interface: anthropogenic habitat use, phylogeny and body mass drive risk of cat and dog flea (Ctenocephalides spp.) infestation in wild mammals

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    Spillover of parasites at the domestic animal - wildlife interface is a pervasive threat to animal health. Cat and dog fleas (Ctenocephalides felis and C. canis) are among the world's most invasive and economically important ectoparasites. Although both species are presumed to infest a diversity of host species across the globe, knowledge on their distributions in wildlife is poor. We built a global dataset of wild mammal host associations for cat and dog fleas, and used Bayesian hierarchical models to identify traits that predict wildlife infestation probability. We complemented this by calculating functional-phylogenetic host specificity to assess whether fleas are restricted to hosts with similar evolutionary histories, diet or habitat niches.Over 130 wildlife species have been found to harbour cat fleas, representing nearly 20% of all mammal species sampled for fleas. Phylogenetic models indicate cat fleas are capable of infesting a broad diversity of wild mammal species through ecological fitting. Those that use anthropogenic habitats are at highest risk. Dog fleas, by contrast, have been recorded in 31 mammal species that are primarily restricted to certain phylogenetic clades, including canids, felids and murids. Both flea species are commonly reported infesting mammals that are feral (free-roaming cats and dogs) or introduced (red foxes, black rats and brown rats), suggesting the breakdown of barriers between wildlife and invasive reservoir species will increase spillover at the domestic animal - wildlife interface.Our empirical evidence shows that cat fleas are incredibly host-generalist, likely exhibiting a host range that is among the broadest of all ectoparasites. Reducing wild species' contact rates with domestic animals across natural and anthropogenic habitats, together with mitigating impacts of invasive reservoir hosts, will be crucial for reducing invasive flea infestations in wild mammals

    Ch 4. Applying a multi-scale HACCP approach to understanding and preventing zoonotic parasite transmission in urban ecosystems: Echinococcus multilocularis and Alveolar Echinococcosis in North America.

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    Echinococcus multilocularis is an emerging zoonotic parasitic of the family Taenidae, and it is the causative agent of alveolar echinococcosis (AE) in humans, a disease with a case mortality rate of up to 90 per cent when untreated. The natural cycle of the disease involves wild canids as the definitive hosts and rodents that serve as the intermediate hosts. Infection of humans occurs through accidental ingestion of parasite eggs through contaminated food or close interactions with infected domestic dogs. In this chapter we describe the complex transmission dynamics of E. multilocularis at the interface of wildlife, domestic animals, humans and the environment, focusing on the emerging situation in a North American urban setting. We describe key ecological and socioeconomic factors that affect parasite distribution and the subsequent risk for humans at different geographical (local, regional and global) and temporal (seasonal and pluri-annual) scales. We also present various parasite control and risk management options based on a hazard analysis and critical control point (HACCP) approach

    Egg intensity and freeze-thawing of fecal samples affect sensitivity of Echinococcus multilocularis detection by PCR.

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    Echinococcus multilocularis is one of the most relevant zoonotic parasites with about 18,000 human cases per year. Its detection in wild host is crucial for disease prevention. The present study aimed to determine factors affecting the sensitivity of E. multilocularis detection by PCR using DNA extracted from fecal samples of coyotes (Canis latrans). Fecal samples were screened for the presence of Taeniidae eggs through centrifugation and sedimentation. DNAwas extracted from fecal samples with and without prior freeze-thawing of the sample and then subjected to PCR targeting a mitochondrial gene (nad1) and a multi-loci microsatellite marker (EmsB). The presence of PCR inhibitors was determined through internal amplification control. Subjecting the sample to repeated freeze-thaw cycles significantly increased the sensitivity of the PCR by 20 %. Likewise, egg intensity had a significant effect on PCR, an effect which was more pronounced for samples not subjected to freeze-thawing. Two ormore eggs per gram of feces significantly increased the odds for a positive PCR outcome. The presence of PCR inhibitors had no effect on PCR in samples subjected to freeze-thaw cycles, whereas in samples not subjected to freeze-thaw cycles, the presence of PCR inhibitors was associated with a 0.78 lower odds ratio of positive PCR outcome. Targeting a nuclear versus a mitochondrial gene did not have a significant effect on the sensitivity of PCR. We recommend freeze-thawing samples prior to DNA extraction to become a standard procedure for E. multilocularis detection in canid feces

    Feeding ecology informs parasite epidemiology: prey selection modulates encounter rate with Echinococcus multilocularis in urban coyotes.

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    We investigated the role of urban coyote feeding ecology in the transmission of Echinococcus multilocularis, the causative agent of Alveolar Echinococcosis in humans. As coyotes can play a main role in the maintenance of this zoonotic parasite within North American urban settings, such study can ultimately aid disease risk management. Between June 2012 and June 2013, we collected 251 coyote feces and conducted trapping of small mammals (n = 971) in five parks in the city of Calgary, Alberta, Canada. We investigated E. multilocularis epidemiology by assessing seasonal variations of coyote diet and the selective consumption of different rodent intermediate host species. Furthermore, accounting for small mammal digestibility and coyote defecation rates we estimated the number of small mammal preys ingested by coyote and consequently, coyote encounter rates with the parasite. Dominant food items included small mammals, fruit and vegetation, although hare and deer were seasonally relevant. The lowest frequency of occurrence per scat of small mammals was recorded in winter (39.4 %), when consumption of deer was highest (36.4 %). However, highest encounter rates (number of infected hosts predated/season) with E. multilocularis (95% CI: 1.0 - 22.4), combined with the lack of predation on non-competent small mammal species, suggest that winter is the critical season for transmission and control of this parasite. Within the small mammal assemblage, voles (Microtus pennsylvanicus and Myodes gapperi) were the selected preys of urban coyotes and likely played a key role for the maintenance of the urban sylvatic life-cycle of E. multilocularis in Calgary
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