1,720,962 research outputs found
Development of disease risk assessment on invasive alien species: evaluation of the risk of introduction of new infections and spread of local ones
No full textInvasive alien species (IAS) represent one of the main global threats to biological conservation and can heavily affect human activities. To tackle this issue, the European Community has approved Regulation No 1143/2014 to define a common intervention line. According to it, a list of invasive alien species of Union concern has been defined and will be regularly updated in order to define priority interventions. Although infectious diseases have dramatic impacts on human health, economic sustainability of animal farming and biodiversity conservation, they are rarely included into evaluations due to the methodological complexities of their risk assessment. We used raccoon (Procyon lotor), coypu (Myocastor coypus) and grey squirrel (Sciurus carolinensis) as model species to develop a qualitative methodology for disease risk assessment that allows to assign each IAS’ pathogen into one out of four risk categories, depending on its impacts and the likelihood of the infection to occur. For each IAS we assessed the risk towards humans, domestic animals and wildlife relative to the introduction of new parasites and the amplification of local ones. Additionally we obtained a total disease risk evaluation for every species that included all these aspects. We also estimated the uncertainty level associated with each risk estimate to point out knowledge gaps. The hazard identification, carried through bibliographic review, identified 377 parasite species showing that raccoon is the IAS infected by the highest number of pathogens. The multiple outcomes produced by our approach showed that raccoon plays the highest risk of introduction and spreading of infections toward humans, livestock and wildlife. Moreover, it is the species with the highest uncertainty. This approach provides a method to explore whether alien species, with relatively low impact on biodiversity and human economy, might indeed entail high disease risks, underlining the importance to consider different aspects in the IAS risk assessment
Disease Risk Assessment and Invasive Alien Species: developing a methodological approach to evaluate the risk of introduction of new infections and spread of local ones
No full textInvasive alien species (IAS) represent one of the main global threats to biological conservation and can even exert a great impact on human activities. To cope with this issue, the European Community has recently approved a Regulation (Reg. EU No 1143/2014) to define a common intervention line. According to this Regulation, a list of invasive alien species considered to be of Union concern has been defined and will be regularly updated in order to define priority interventions. Although infectious diseases may play a relevant role in the establishment of IAS and have dramatic impacts on human health, economic sustainability of animal farming and biodiversity conservation, diseases are rarely included into evaluations due to the methodological complexities of their risk assessment. Every mammal species can be indeed infected by up to hundreds of different parasites which can be transmitted to humans, domestic animals and other wildlife. Alien species may thus act as carriers of new infections in the area of release, or as new competent hosts for autochthonous infections, amplifying their local transmission and maintenance. Here we used raccoon (Procyon lotor), coypu (Myocastor coypus) and grey squirrel (Sciurus carolinensis) as model species to develop a qualitative methodology for Disease Risk Assessment that allows to assign each IAS into one out of four discrete risk categories. Assignment to these categories is obtained by scaling the likelihood of infection occurrence over its impact, with each of these two elements defined in turn through four discrete categories. Hazard assessment, determined through the analysis of existing scientific literature, identified a total of 377 parasite species reported in 388 scientific papers. Thus, for each infection, we defined the impact and likelihood of their introduction or local amplification in relation to transmission to humans, domestic animals or other wildlife. Based on these data, for each of the three IAS we assessed the risk towards humans, domestic animals and other wildlife relative to the introduction of new parasites and the amplification of local ones. Additionally, for each host species we obtained a total disease risk evaluation that included all these partial aspects. Concurrently, we also carried out evaluations to determine the uncertainty level associated with each of the risk estimates. Our analyses showed that the raccoon is the IAS infected by the highest number of parasite species (n=198), followed by grey squirrel (n=136) and coypu (n=44). The risk of introducing new parasites is thus higher for the raccoon, which may carry 37 high risk parasites: 16 zoonotic, 12 transmissible to domestic animals and 9 to wildlife. On the contrary, coypu presents the lowest risk of introducing new parasites with only 2 high risk parasites transmissible to humans and wildlife and 1 to domestic animals. Similarly, even the risk of amplifying local parasites is highest in raccoon, which may be infected by 16 parasite species that represent a high risk for humans and 6 for domestic and wild animals. Coypu resulted again the least risky species, with 4 high risk infections for humans and wildlife and 2 for domestic animals. As a consequence, the overall disease risk is higher for raccoons with 27 high risk infections for humans, 15 for domestic animals and 12 for wildlife, whereas coypu is the least risky species with 5 infections for humans and wildlife and 2 towards domestic animals. Finally, the risk estimates relative to raccoon shows the highest level of uncertainty and respect the coypu’s the lowest level. These results show that some alien species, despite having a relatively low impact on biodiversity and human economy, might indeed entail high disease risks, whereas species with a high environmental impact may pose negligible disease risks. The present methodological approach represents a first step towards a broader development of a disease risk analysis on a more comprehensive number of invasive alien species. Other than providing information on disease risk, the output of this assessment can serve as a guideline to indicate those knowledge gaps that should be covered. In particular, disease risk assessment should integrate experts’ opinions that define likelihoods of infection of less investigated parasite species with a participated involvement of stakeholders to better incorporate the perceived impacts. Once these results will be achieved, risk management plans to mitigate the potential disease impact posed by IAS could be defined
Valutazione del rischio sanitario delle specie invasive alloctone
No full textIntroduzione
La traslocazione di specie animali è alla base dell’emergenza/ri-emergenza di numerose malattie infettive. Le specie
alloctone invasive, in quanto specie introdotte dall’uomo al di fuori del proprio areale di origine, rappresentano un
potenziale rischio sanitario per la salute pubblica ed animale. Essendo il numero di introduzioni in costante crescita, il Reg.
UE n. 1143/2014 ha previsto l’istituzione di una lista di specie prioritarie su cui focalizzare gli interventi preventivi e
gestionali, sulla base di criteri di impatto sanitario, ambientale ed economico. Ad oggi però, sebbene siano state sviluppate
numerose metodologie per la valutazione del rischio ambientale, non è data adeguata attenzione agli aspetti sanitari, e
ancora manca una metodica che permetta la stima del rischio sanitario in questo contesto.
Obiettivi
Il nostro obiettivo è quello di sviluppare uno strumento qualitativo di valutazione del rischio sanitario rappresentato da
specie invasive di mammiferi verso uomo, animali domestici e fauna selvatica autoctona, che permetta agli amministratori
ed ai gestori locali di identificare le specie prioritarie su cui focalizzare le misure di prevenzione/controllo.
Metodi
Per raggiungere tale obiettivo, seguendo gli step necessari per eseguire una valutazione del rischio sanitario, abbiamo
identificato gli eventi attraverso cui una specie invasiva animale può influenzare le dinamiche di trasmissione delle infezioni
nel suo areale di introduzione. Lo strumento di valutazione del rischio si sviluppa attraverso una expert elicitation basata su
una serie di domande qualitative atte a valutare i fattori inerenti alla specie invasiva e all’areale di introduzione che
influenzano tali eventi.
Risultati.
L’analisi ha messo in evidenza due modalità principali di incremento del rischio sanitario locale: una di tipo diretto, data
dall’azione della specie come introduttore di nuovi patogeni o amplificatore di patogeni già presenti, e una di tipo indiretto,
data dalle possibili interazioni della specie invasiva con specie ospiti presenti nell’area.
Conclusioni
I meccanismi implicati nell’incremento del rischio sanitario locale in seguito all’introduzione di una specie invasiva sono
molteplici e complessi, potendo avvenire l’uno in concomitanza con l’altro ed essendo fortemente influenzati dal contesto.
Mentre i meccanismi di tipo indiretto risultano difficilmente prevedibili, quelli di tipo diretto possono essere integrati
all’interno di una metodologia di valutazione del rischio, tenendo conto dei limiti dati dalla complessità del sistema e dalla
carenza di dati riguardante le infezioni delle specie invasive
Valutazione dell’efficacia delle strategie di intervento per il controllo delle malattie infettive attraverso la simulazione matematica della dinamica di infezione
No full textIntroduzione
Le strategie di gestione sanitaria delle infezioni sono disparate, variano tra loro per efficacia, costo e realizzabilità, ma in molti casi manca un’analisi comparativa e sistematica della loro efficacia e questa mancanza rende controversa la scelta della migliore strategia per la gestione sanitaria di un’infezione. L’utilizzo di modelli matematici, permettendo la simulazione a priori della dinamica delle infezioni in diversi scenari, consente un’analisi sistematica degli effetti degli interventi sulle popolazioni di interesse, e rappresenta uno strumento efficace per le scelte di gestione sanitaria. Un esempio di infezione la cui gestione sanitaria è ancora dibattuta è Baylisascaris procyonis, un elminta il cui ospite definitivo è il procione (Procyon lotor). L’ingestione delle forme infettanti di B. procyonis da parte dell’uomo può essere causa di sindrome da larva migrans, ad esito anche fatale, ma ad oggi non esiste una strategia d’intervento d’elezione per questa infezione. Le strategie attualmente prese in considerazione spaziano dalla rimozione dei procioni infetti, alla rimozione delle feci dall’ambiente, al trattamento antiparassitario degli animali.
Obiettivi
Per effettuare una corretta valutazione a priori dell'efficacia delle suddette strategie, è stato sviluppato un modello matematico per lo studio della dinamica di B. procyonis, simulando l'effetto dei diversi interventi.
Metodi
È stato innanzitutto elaborato un modello deterministico di tre equazioni differenziali, adattato all’interazione tra le popolazioni ospite (procione) e parassita (adulti e fase infettante di B. procyonis). Sono stati poi simulati i tre tipi di intervento gestionale (depopolamento, somministrazione di antielmintici e rimozione di feci dall’ambiente), dei quali è stato valutato l’effetto sull'infestazione ambientale delle forme infettanti. Le simulazioni sono state adattate a due diversi scenari, il caso di una popolazione parassitaria stabilizzata, e quello di una popolazione parassitaria in espansione.
Risultati
Le simulazioni hanno evidenziato come il metodo più rapido per l'eliminazione delle forme infettanti dall’ambiente sia la rimozione delle feci, ma come questo metodo necessiti di un grande sforzo di intervento per ottenere il risultato desiderato. La somministrazione di antielmintici e la rimozione dei procioni dall’area di intervento risultano invece più lenti nell’eliminare le forme infettanti, ma quest'ultima strategia permette il conseguimento del risultato con un minor sforzo, risultando quindi l'intervento più idoneo.
Conclusioni
I risultati ottenuti evidenziano come l’utilizzo di un modello matematico rappresenti un valido strumento per la valutazione a priori dell'efficacia e dell'applicabilità delle strategie di gestione sanitaria delle infezioni, permettendo l'individuazione della tipologia di intervento più adatta in base alle risorse disponibili e alle tempistiche desiderate
Development of a qualitative expert-based tool to assess invasive alien species disease risk
No full textIncreased global trade and travel have led to a rise in the number of invasive alien species (IAS) worldwide. Despite the acknowledgement of the substantial role wild species translocations pose in the emergence and re-emergence of pathogens of public health relevance, IAS are mainly studied for their environmental impacts and their disease risk towards humans and animals is still largely neglected. IAS, acting as hosts, may alter the infection dynamics in their area of release by introducing new pathogens or amplifying the local ones. Hence, early identification of IAS of possible health concern, i.e. the ones that, if successfully established in the area, would represent the highest disease risk, would allow to take the adequate preventive measures against their introduction and/or to manage them as a priority if they have been already introduced.
Existing risk assessment frameworks are unsuitable to address the multifaceted nature of disease risk posed by IAS. To this end, we have adapted existing qualitative risk assessment frameworks and developed a tool allowing systematic prioritisation of IAS based on the pathogens of public health relevance that may be spread to relevant targets (humans, livestock or wildlife) in a selected area of interest. The tool is framed around two main risk pathways aimed at characterising the risk of introduction and amplification of newly introduced and locally acquired pathogens respectively. For a given IAS, through a comprehensive set of qualitative questions aimed at characterising the epidemiological, environmental and biological factors increasing or decreasing the disease risk along the pathways, the tool generates the list of relevant pathogens at high, medium, low or negligible risk towards humans, livestock or wildlife. Thought to be used by a multi-disciplinary working group of experts, the tool allows for comparison of different IAS and therefore, systematic identification of IAS that should be prioritised
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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