1,720,969 research outputs found
PROBABILISTIC MODELLING IN FOOD SAFETY: A SCIENCE-BASED APPROACH FOR POLICY DECISIONS
Full text linkThis thesis deals with use of qualitative and quantitative probabilistic models for the animal-derived food safety management. Four unrelated models are presented: three quantitative and one qualitative. Two of the quantitative models concern the risk posed by pathogens in raw milk, in the first study, a probabilistic approach for the inclusion of the variability and the uncertainty in the consumers’ habits and the bacterial pathogenic potential is proposed while the second study, demonstrate how the overlook of the relationship between the storage time and temperature has led to overestimated results in raw milk-related models published so far and an equation to address the issue is provided. In the third study, quantitative modelling techniques are used to simulate the dynamics underlying the spread of Campylobacter in broiler flocks and quantify the potential effects that different on-farm mitigation strategies or management measures have on the microbial load in the intestine of infected birds at the end of the rearing period. In the qualitative study, a general approach for the estimation of the likelihoods of introduction of live parasites in aquaculture implants and the commercialization of infested product is outlined by using the example of Anisakids in farmed Atlantic salmon
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
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
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
Exploratory data analysis Listeria monocytogenes in dairy production process: an exploration of available data
No full textDue to the insufficient qualitative data of Listeria monocytogenes in production environment, this study
was aimed to evaluate the possibility to extract from a historical database useful information about
the occurrence of Listeria monocytogenes in different production process areas. Estimated probabilities
(p) and confidence limit (CL) were calculated using 3276 environmental samples data analysed
by GLMM model. The attempt to use historical data to estimate the occurrence of Listeria monocytogenes
in processing environment leads for some areas to high p value wide CL. The results suggest
the need for a targeted environmental sampling plan and provides some estimate sampling size
Consumers' behavior in quantitative microbial risk assessment for pathogens in raw milk: Incorporation of the likelihood of consumption as a function of storage time and temperature
Full text linkFoodborne disease as a result of raw milk consumption is an increasing concern in Western countries. Quantitative microbial risk assessment models have been used to estimate the risk of illness due to different pathogens in raw milk. In these models, the duration and temperature of storage before consumption have a critical influence in the final outcome of the simulations and are usually described and modeled as independent distributions in the consumer phase module. We hypothesize that this assumption can result in the computation, during simulations, of extreme scenarios that ultimately lead to an overestimation of the risk. In this study, a sensorial analysis was conducted to replicate consumers' behavior. The results of the analysis were used to establish, by means of a logistic model, the relationship between time–temperature combinations and the probability that a serving of raw milk is actually consumed. To assess our hypothesis, 2 recently published quantitative microbial risk assessment models quantifying the risks of listeriosis and salmonellosis related to the consumption of raw milk were implemented. First, the default settings described in the publications were kept; second, the likelihood of consumption as a function of the length and temperature of storage was included. When results were compared, the density of computed extreme scenarios decreased significantly in the modified model; consequently, the probability of illness and the expected number of cases per year also decreased. Reductions of 11.6 and 12.7% in the proportion of computed scenarios in which a contaminated milk serving was consumed were observed for the first and the second study, respectively. Our results confirm that overlooking the time–temperature dependency may yield to an important overestimation of the risk. Furthermore, we provide estimates of this dependency that could easily be implemented in future quantitative microbial risk assessment models of raw milk pathogens
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
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