1,720,963 research outputs found
First record of Hepatozoon spp. in Alpine wild rodents: implications and perspectives for transmission dynamics across the food web
Get PDFAmong the Apicomplexa parasites, Hepatozoon spp. have been mainly studied in domestic animals and peri-urban areas. The epidemiology of Hepatozoon spp. is poorly investigated in natural systems and wild hosts because of their scarce veterinary and economic relevance. For most habitats, the occurrence of these parasites is unknown, despite their high ecosystemic role. To fill this gap for alpine small mammals, we applied molecular PCR-based methods and sequencing to determine the Hepatozoon spp. in 830 ear samples from 11 small mammal species (i.e., Apodemus, Myodes, Chionomys, Microtus, Crocidura and Sorex genera) live-trapped during a cross-sectional study along an altitudinal gradient in the North-Eastern Italian Alps. We detected Hepatozoon spp. with an overall prevalence of 35.9%. Two species ranging from 500 m a.s.l. to 2500 m a.s.l. were the most infected: My. glareolus, followed by Apodemus spp. Additionally, we detected the parasite for the first time in another alpine species: C. nivalis at 2000–2500 m a.s.l. Our findings suggest that several rodent species maintain Hepatozoon spp. along the alpine altitudinal gradient of habitats. The transmission pathway of this group of parasites and their role within the alpine mammal community need further investigation, especially in consideration of the rapidly occurring environmental and climatic changes
Seasonal and environmental determinants of small mammals and their zoonotic potential across a wide latitudinal and altitudinal gradient
No full textThe functional role and position of a species within the environment is strongly governed by the interplay between species internal state, abiotic and biotic environmental conditions, as well as by multi-species interactions (predation, competition and parasitism). In this work we have implemented a multifactorial niche-based approach to evaluate the consequences and patterns of environmental, climate and anthropic changes on small mammal populations and assemblages, considering also the cascading effects on parasite loads and thus on emergence of zoonotic and non-zoonotic diseases. To achieve this goal, we carried out a treatment-control experiment with supplemental ad libitum food accessible all-yearround to woodland rodents at two latitudinal extremes i.e. Norway (from 2013 to 2015) and Italy (from 2019 to 2021). Secondly, we assessed the composition of small mammal assemblages across a wide altitudinal gradient (from 500 to 2500 m a.s.l.) in the Italian Alps (2019–2020). In both studies, we livetrapped small mammal species using a capture-mark-recapture approach. In Italy only, we counted the tick burden on rodents and collected biological samples (ear biopsy, blood sample) and molecular and serological screenings were subsequently performed for rodent- and vector-borne pathogens assessment. Within this work, we captured a total of 917 small mammals in Norway and 830 in Italy. In the latitudinal comparison, only bank vole (Myodes glareolus) was sampled in Norway, while two mice species (Apodemus sylvaticus and A. flavicollis) and bank vole in Italy. Within this comparison, we found that individual rodent survivorship seemed to be governed by seasonal cycles and overridden by food availability only when unfavourable conditions occurred. Conversely, local population size generally increased with supplemental food availability, unless when both mice and voles were sympatric (in Italy only). In this case, the dominant species (i.e., Apodemusspp.) performed better both on survival and population size respect to the subordinate one (i.e., M. glareolus). In Italy, rodent abundance and spatial aggregation registered at sites provided with supplemental food favoured also tick burden on rodent hosts, especially on heavier animals. Beyond exploitation of rodent hosts, ticks were also favoured by less-limiting climatic conditions, indeed we sampled them at 2000–2500 m a.s.l., the highest altitude at which ticks were recorded in central Europe. At those altitudes, representing the cold and remote edges of small mammal distribution, we monitored the distributional overlap of snow vole (Chionomys nivalis), field voles (Microtus spp.) and unexpectedly of bank vole, which occupied also woodland habitats in sympatry with mice. Further, we also detected an altitudinal pattern among vector-borne pathogens, with Borrelia spp. infection at low altitudes, while Anaplasma phagocytophilum and Babesia microti mainly occurred at high altitudes. Beyond these common vectorborne pathogens, we also found Hepatozoon spp. along the entire altitudinal gradient and on snow voles for the first time. These findings suggest that modifications in rodent demography and community structure, as well as host-parasite association, were favoured by homogeneous and human-disrupted areas such as at ungulate feeding stations. In these areas, if tick density in the environment is supportive, the presence of both rodents and deer may favour the completion of tick life cycle and enhance pathogens circulation among hosts. Moreover, the generalist species (e.g. M. glareolus), that occurred along a wide altitudinal range in sympatry with more specialist (e.g. Apodemus spp.) and climate-sensitive ones (e.g. C. nivalis), may be prone to upward distributional shifts and further promote the geographic expansion of arthropod vectors. This may also facilitate the spread and transmission of zoonotic pathogens under a climate change context. Overall, this study suggests that the multiple extrinsic and intrinsic environmental facets and biotic interspecific forces governing small mammal demography and communities should be considered ensemble using a multi-factorial approach, especially in perturbed ecosystems. Further, changes in small mammal populations and communities seem to alter host-vectorpathogen interactions, increasing the risk of transmission of infectious diseases both on wildlife and humans
Interspecific competition between mice and voles induced by ad libitum food resources: a simulation of climate change effects on sympatric species?
No full textHow resources are partitioned among sympatric species is conditional to extrinsic (e.g. climate driven) and intrinsic (e.g. demography-dependent) factors. To analyse these effects, we carried out a treatment-control experiment with supplemental ad libitum food accessible to the community of wild rodents, throughout seasons at two latitudinal extremes. We intensively live-trapped woodland rodents in north-eastern Italian Alps (2019 – 2021) and in south-eastern Norway (2013 – 2015), and applied multistate open robust design models to estimate the variability of demographic parameters under the experimental settings. Rodent assemblage was different at the two latitudes, with yellow-necked mouse, wood mouse (Apodemus spp.) and bank vole (Myodes glareolus) living in sympatry in Italy, whereas only bank vole occurred in Norway. In Norway, food scarcity and harsh climate seemed to limit rodent survival and abundance. In Italy, supplemental food promoted mice abundance, which in turn seemed to depress voles survival and abundance, most likely due to inter-specific behavioural and exploitative competition. The competitive mechanisms which we induced by providing ad libitum food resources may simulate population responses under climate change scenarios, with generalist species (e.g. Muridae) becoming prevalent part of the assemblage and overriding specialist species (e.g. Arvicolinae), also at the current extremes of their distribution range
Rodents and pathogens distribution along an altitudinal gradient in the Italian Alps
No full textIn a global change context, the association between generalists and specialists could be a determinant of ecosystem stability. This holds particularly true in mountain ecosystems, where the environmental tolerance of generalists to global warming may lead to their upward distributional shifts, while a decline is expected in specialists. As a consequence, even the parasites that these species carry can shift, eventually promoting the emergence of infectious diseases in newly colonized areas. We examined these relationships in small mammals along an altitudinal gradient in the Italian Alps (Province of Trento), where we identified 5 altitudinal belts from 500 to 2500 m a.s.l. with 500-meter intervals. We live-trapped small mammals applying capture-mark-recapture technique in 2019 and 2020. We counted ticks on rodents and collected blood and ear biopsy samples. Molecular PCR based methods coupled with sequencing and serological assays were performed for vector- and rodent-borne pathogens screening. We analysed probability of infection with Generalized Linear Mixed Models . Overall, we captured 333 animals belonging to 11 species (Apodemus flavicollis, A. sylvaticus, Chionomys nivalis, Microtus arvalis, M. subterraneus, M. agrestis, Myodes glareolus, Sorex araneus, S. alpinus, S. minutus, Crocidura leucodon). Apodemus spp. and My. glareolus were sympatric in the montane belt, from 500 to 1500 m a.s.l. My. glareolus was also present in the alpine belts, from 2000 to 2500 m, together with C. nivalis, Microtus spp. and shrews. We counted 3782 feeding-ticks belonging to the genus Ixodes. From the molecular screening of 324 ear samples we detected an unevenly altitudinal pattern of tick-borne pathogens distributions , with Borrelia spp. occurring up to 1500 m a.s.l. (prevalence 13.88%), while Anaplasma phagocytophilum (7.09%) and Babesia microti (3.08%) mainly recorded in alpine belts. We screened 440 sera samples and detected Dobrava virus in A. flavicollis (0.8%). Also 10% C. nivalis tested positive to both Dobrava/Puumala viruses. All samples tested negative for Tick-borne encephalitis virus. The observed altitudinal segregation in pathogens distribution revealed that this factor acted in a space-for-time way, mimicking the long-term temporal climatic variations expected under global warming. This may be explained by the presence of a more specialist endophilic tick species at higher altitudes that solely utilize small mammals as hosts for all developmental stages (e.g., Ixodes trianguliceps). Moreover, our findings supported the expansion of the generalist species My. glareolus toward higher altitudes, where specialists, such as C. nivalis, resulted restricted only in some specific habitats. The potential replacement of specialists by generalists can cause an homogenization at the community level, which in turn could alter ecosystem functioning and host-parasite-pathogen association, with implication for spreading of emerging infectious diseases
EUROSMALLMAMMALS: a network for collaborative science in small mammal ecology
No full textEnvironmental, climatic and anthropogenic modifications constantly impact worldwide ecosystems resulting in global scale biological responses across all ecological levels (individual, population, species and community). As a consequence living organisms can adapt their niche breadth either via genetic evolution and phenotypic plasticity or through distributional shifts, which may alter the communities, lead to novel host–vector species pairings and to the emergence of infectious disease. To detect and investigate these responses on wildlife, animals often require long-term monitoring studies or (possibly) retrospective spatio-temporal longitudinal studies across environmental gradients. Small mammals are an elusive group of animals particularly important for their ecological and epidemiological role, and for their capability to track environmental and climatic changes through functional and numerical responses. In this context, data sharing and reuse can play a crucial role to address unforeseen questions on global changes across a broad range of habitats and species. In 2019 within the collaborative network “EUROMAMMALS ́’ (https://euromammals.org), we have initiated a new branch specifically dedicated to small mammals named EUROSMALLMAMMALS. Our aim is to promote collaborative open science and networking among scientists involved in small mammal ecology across Europe, for connecting different species-specific bottom-up projects. From 2019, we contacted 20 European researchers involved in small mammal projects and 4 had requested to join the network later. In order to promote data sharing of reliable, standardized and harmonized data, partners were encouraged to fill a specific questionnaire in which they can provide the metadata of their projects. These metadata served as reference to translate small mammal data collection protocols into a relational database built under open-software platforms (PostgreSQL, PostGIS, Django, OpenLayers, Bootstrap, jQuery). Data included all the aspects covered during a small mammal study: study area characteristics, type of experimental designs, local environmental and climatic data, descriptors of capture events, data derived from laboratory and epidemiological analyses. Further, the partners shared their raw data which passed through quality check and harmonization process and then included in the database. At December 2021, 15 partners belonging to 9 countries across Europe (Spain and Andorra, France, Germany, Italy, Norway, Poland, Czech Republic, Albania) joined the network. The data, spanning from 1990 to 2019, included 48 small mammal species (e.g. voles, mice, glirids, lemmings and shrews), 70562 captures, 113 study areas and 7 pathogens (e.g. hantavirus, Leptospira spp., Borrelia spp., Babesia spp., TBEv, Anaplasma phagocytophilum and Hepatozoon spp.). Generally, the animals were captured applying live or snap-trapping methods. Moreover, some small mammal data derived from owl pellets analyses are included. We created a EUROSMALLMAMMALS website (https://eurosmallmammals.org) which includes project aim, scientific purposes and outputs, and a mailing list dedicated to the partners ([email protected]) to improve communication. EUROSMALLMAMMALS collaborative network is constantly expanding throughout European countries, involving partners that cover different fields of interest, e.g. population demography and dynamics, epidemiology, conservation genetics, community composition, prey-predator dynamics and landscape ecology. By scaling up the knowledge from the individual to the ecosystem and by sharing data and expertise on small mammals’ populations, this initiative could give the opportunity to fill some important knowledge gaps and provide novel perspectives to evaluate the effect of global changes on species distribution, ecosystems functioning and epidemiological aspects
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Are generalists species replacing specialists? Implications of hosts species distribution on tick-borne diseases along an altitudinal gradient in the Italian Alps.
No full textIntroduction In a global change context, the association between generalists and specialists could be a determinant of ecosystem stability. This holds particularly true in mountain ecosystems, where the environmental tolerance of generalists to global warming may lead to upward distributional shifts and thus declining of specialists. As a consequence of this altitudinal expansion, even the parasites that these species carry can shift, eventually promoting the emergence of infectious diseases in newly colonized areas. We examined these relationships in small mammals along an altitudinal gradient of Alpine habitats, analysing the differences in small mammals’ assemblage and pathogens’ occurrence. Methods We capture-mark-recaptured wild small mammals from 500 to 2500 m a.s.l. at 500-meters intervals in the Italian Alps, in 2019 and 2020. We counted ticks on rodents and collected ear biopsy samples. Molecular PCR-based methods coupled with sequencing and serological assays were performed for vector-borne pathogens screening. We analysed small mammal species assemblages and probability of infection along the altitudinal gradient with Redundancy Detrended Analysis (RDA) and Generalized Linear Mixed Models (GLMMs). Results In total we captured 333 animals belonging to 11 species (Apodemus flavicollis, A. sylvaticus, Chionomys nivalis, Microtus arvalis, M. subterraneus, M. agrestis, Myodes glareolus, Sorex araneus, S. alpinus, S. minutus, Crocidura leucodon) and counted 3782 ticks (3718 larvae and 64 nymphs) belonging to the genus Ixodes. A. flavicollis and My. glareolus occupied in sympatry the montane belts, from 500 to 1500 m a.s.l. My. glareolus was also present in the alpine belts, from 2000 to 2500 m, together with C. nivalis, Microtus spp. and shrews. We also detected an unevenly altitudinal pattern of distributions of vector-borne pathogens, with Borrelia spp. occurring up until 1500 m a.s.l. (prevalence 13.88%), while Anaplasma phagocytophilum (7.09%) and Babesia microti (3.08%) mainly recorded in alpine belts. Conclusions Wild rodents are important reservoirs of numerous tick-borne pathogens. The altitudinal segregation that we found, revealed that also parasites are affected by climate, as shown by the presence of A. phagocytophilum and B. microti at higher altitudes where I. ricinus has never been recorded. This made us speculate on the presence of a more specialist endophilic tick species that solely utilize small mammals as hosts for all developmental stages (such as Ixodes trianguliceps). Moreover, our findings support the expansion of the generalist species My. glareolus toward higher altitudes, where specialists, such as C. nivalis, were restricted only in some specific habitats. The potential replacement of specialists by generalists can cause an homogenization at the community level which in turn could alter ecosystem functioning, including the host-parasite-pathogen association with implication for emerging infectious diseases spread
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