1,289 research outputs found

    Mobile-Based Analysis of Malaria-Infected Thin Blood Smears: Automated Species and Life Cycle Stage Determination

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    Microscopy examination has been the pillar of malaria diagnosis, being the recommended procedure when its quality can be maintained. However, the need for trained personnel and adequate equipment limits its availability and accessibility in malaria-endemic areas. Rapid, accurate, accessible diagnostic tools are increasingly required, as malaria control programs extend parasite-based diagnosis and the prevalence decreases. This paper presents an image processing and analysis methodology using supervised classification to assess the presence of malaria parasites and determine the species and life cycle stage in Giemsa-stained thin blood smears. The main differentiation factor is the usage of microscopic images exclusively acquired with low cost and accessible tools such as smartphones, a dataset of 566 images manually annotated by an experienced parasilogist being used. Eight different species-stage combinations were considered in this work, with an automatic detection performance ranging from 73.9% to 96.2% in terms of sensitivity and from 92.6% to 99.3% in terms of specificity. These promising results attest to the potential of using this approach as a valid alternative to conventional microscopy examination, with comparable detection performances and acceptable computational times.Financial support from North Portugal Regional Operational Programme (NORTE2020), Portugal 2020 and the European Regional Development Fund (ERDF) from the European Union through the project Deus ex Machina: Symbiotic Technology for Societal Efficiency Gains’, NORTE-01-0145-FEDER-000026.N/

    First description of food-borne Salmonella enterica resistance regions R1 and R3 associated with IS26 elements

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    In this study, we assessed the presence of IS26 in food-borne ASSuT-type Salmonella enterica isolates. A new genetic region (R3) wasdescribed, that included a C14 caspase gene between IS26 elements. R3 was present in two Salmonella Rissen isolates from a swine carcass anda meat handler, collected at the same abattoir. Furthermore, a new rearrangement of resistance region R1, harboring the blaTEM-1 gene flanked byIS26 elements, was identified in Salmonella Typhimurium and Salmonella 4,[5],12:i:-, from different samples. This study highlights the zoonoticpotential of Salmonella spp. isolates and the possible role of IS26 in the mobilization of resistance genes.In this study, we assessed the presence of IS26 in food-borne ASSuT-type Salmonella enterica isolates. A new genetic region (R3) wasdescribed, that included a C14 caspase gene between IS26 elements. R3 was present in two Salmonella Rissen isolates from a swine carcass anda meat handler, collected at the same abattoir. Furthermore, a new rearrangement of resistance region R1, harboring the blaTEM-1 gene flanked byIS26 elements, was identified in Salmonella Typhimurium and Salmonella 4,[5],12:i:-, from different samples. This study highlights the zoonoticpotential of Salmonella spp. isolates and the possible role of IS26 in the mobilization of resistance genes

    Protozoa as the “underdogs” for microbiological quality evaluation of fresh vegetables

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    The monitoring of the microbial quality of fresh products in the industrial environment has mainly focused on bacterial indicators. Protozoa, such as Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii, and Cyclospora cayetanensis, are routinely excluded from detection and surveillance systems, despite guidelines and regulations that support the need for tracking and monitoring these pathogens in fresh food products. Previous studies performed by our laboratory, within the scope of the SafeConsume project, clearly indicated that consumption of fresh produce may be a source of T. gondii, thus posing a risk for the contraction of toxoplasmosis for susceptible consumers. Therefore, preliminary work was performed in order to assess the microbiological quality of vegetables, highlighting not only bacteria (Escherichia. coli, Listeria monocytogenes, and Salmonella spp.), but also the zoonotic protozoa G. duodenalis and Cryptosporidium spp. Although all samples were found to be acceptable based on bacteriological parameters, cysts of G. duodenalis and oocysts of Cryptosporidium spp. were observed in vegetables. Moreover, it was possible to genetically characterize G. duodenalis positive samples as assemblage A, a genotype that poses risks to human health. Although these are preliminary results, they highlight the need to include protozoa in the microbiological criteria for foodstuffs, as required by EU Law No. 1441/2007, and to improve inactivation and removal procedures of (oo)cysts in fresh produce and water.info:eu-repo/semantics/publishedVersio

    Carcinogenic Ability of Schistosoma Haematobium Possibly through Oncogenic Mutation of KRAS Gene

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    Schistosoma haematobium is a parasitic flatworm that infects millions of people, mostly in the developing world, and is associated with high incidence of bladder cancer, although why is not clear. Previously, we have used CD-1 mice to show that Schistosoma haematobium total antigen (Sh) has a carcinogenic ability. Sh intravesically instillation induced the development of several urothelial lesions, namely nodular hyperplasia and dysplasia (LGIUN—Low Grade Intra-Urothelial Neoplasia) after 40 weeks of treatment. These results suggested that Sh induce urothelium malignization. Bladder carcinoma frequently harbours gene mutations that constitutively activate the receptor tyrosine kinase-Ras pathway for this reason we studied activating mutations in KRAS gene. Twenty percent of the bladders with dysplasia presented a KRAS mutation in codon 12 of exon 2. We concluded from these results that the parasite extract of S. haematobium has carcinogenic ability possibly through oncogenic mutation of KRAS gene

    Granulomatous-like immune reaction and hepatic fibrosis induced by Schistosoma haematobium immature worms

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    Golden hamsters were inoculated with Schistosoma haematobium cercariae to examine histological lesions at different time points over an 18 month period of infection. Hamsters were sacrificed 26 weeks and 82 weeks after inoculation. The parasite was found in the blood and in the liver of infected animals as was expected, but we found exclusively male worms, no female worms nor eggs. Interestingly we observed unexpected hepatic lesions induced by S. haematobium immature male worms alone in the golden hamster, characteristic of schistosome eggs. Samples from liver, kidneys, lungs, bladder and gastrointestinal tract were collected during necropsy to evaluate injuries induced by S. haematobium. Notably we observed hepatitis in the liver of infected hamsters, no lesions were found in other organs. We also found liver fibrosis in infected hamsters. This study provides further experimental evidence for the role that schistosome worms, and their derived antigens, may play in the pathology of the infection and modulation of liver chronic inflammation in the murine model of schistosomiasis

    Schistosome and liver fluke derived catechol-estrogens and helminth associated cancers.

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    Infection with helminth parasites remains a persistent public health problem in developing countries. Three of these pathogens, the liver flukes Clonorchis sinensis, Opisthorchis viverrini and the blood fluke Schistosoma haematobium, are of particular concern due to their classification as Group 1 carcinogens: infection with these worms is carcinogenic. Using liquid chromatography-mass spectrometry (LC-MS/MS) approaches, we identified steroid hormone like (e.g., oxysterol-like, catechol estrogen quinone-like, etc.) metabolites and related DNA-adducts, apparently of parasite origin, in developmental stages including eggs of S. haematobium, in urine of people with urogenital schistosomiasis, and in the adult stage of O. viverrini. Since these kinds of sterol derivatives are metabolized to active quinones that can modify DNA, which in other contexts can lead to breast and other cancers, helminth parasite associated sterols might induce tumor-like phenotypes in the target cells susceptible to helminth parasite associated cancers, i.e., urothelial cells of the bladder in the case of urogenital schistosomiasis and the bile duct epithelia or cholangiocytes, in the case of O. viverrini and C. sinensis. Indeed we postulate that helminth induced cancers originate from parasite estrogen-host epithelial/urothelial cell chromosomal DNA adducts, and here we review recent findings that support this conjecture

    Farming for nature in the Montado: the application of ecosystem services in a results-based model

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    The Montado is a silvopastoral system with a tree cover of predominantly Quercus suber but also Quercus rotundifolia, where cattle or sheep graze the understory. It occupies more than one million hectares in southern Portugal, and a similar landscape, the Dehesa, covers ca. three million hectares in Spain. These silvopastoral systems can simultaneously benefit the environment and socio-economic activities by providing a bundle of ecosystem services (ESs). However, an ongoing trend of decline in tree density and the covered area is threat-ening such provision. Policies are needed to motivate farmers to secure the ESs that they provide. One possible format is the development of a results-based model (RBM) for agri-environment schemes (AES), implemented under the Common Agricultural Policy. In an RBM, farmers are paid when they deliver specific environmental results (ERs) (e.g. healthy and functional soils), that are linked with the provision of different (and often mul-tiple) ESs. This study defines possible ERs for the Montado and details how these results are linked to the pro-vision of ESs. It then considers management actions that can allow the achievement of these ERs and the costs of these actions. Our methodological approach is based on a transdisciplinary dialogue involving researchers, practitioners (i.e farmers), public authorities and policy makers. The results of the process include the identi-fication of four main ERs: a healthy soil ecosystem, a biodiverse native-Mediterranean pasture, an oak tree layer where regeneration exists (i.e. trees of different ages), and preserved or enhanced landscape elements, for example riparian galleries with vegetation. These ERs increase the supply of provisioning services (e.g. cork production), of regulating services, (e.g. carbon sequestration), and cultural services (e.g. aesthetic inspiration). RBMs allow farmers to use any management practice they choose as the focus is on the results. Nonetheless, to estimate costs we identified 12 potential strategic management practices (and their cost) along with the technical support that farmers would need. We conclude that an RBM could be an affordable solution for public policies in the Montado system, given the limited government budget for supporting AES.info:eu-repo/semantics/publishedVersio

    SARS-CoV-2 air and surface contamination in residential settings

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    © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.SARS-CoV-2 transmission occurs mainly indoors, through virus-laden airborne particles. Although the presence and infectivity of SARS-CoV-2 in aerosol are now acknowledged, the underlying circumstances for its occurrence are still under investigation. The contamination of domiciliary environments during the isolation of SARS-CoV-2-infected patients in their respective rooms in individual houses and in a nursing home was investigated by collecting surface and air samples in these environments. Surface contamination was detected in different contexts, both on high and low-touch surfaces. To determine the presence of virus particles in the air, two sampling methodologies were used: air and deposition sampling. Positive deposition samples were found in sampling locations above the patient's height, and SARS-CoV-2 RNA was detected in impactation air samples within a size fraction below 2.5 μm. Surface samples rendered the highest positivity rate and persistence for a longer period. The presence of aerosolized SARS-CoV-2 RNA occurred mainly in deposition samples and closer to symptom onset. To evaluate the infectivity of selected positive samples, SARS-CoV-2 viability assays were performed, but our study was not able to validate the virus viability. The presented results confirm the presence of aerosolized SARS-CoV-2 RNA in indoor compartments occupied by COVID-19 patients with mild symptoms, in the absence of aerosol-generating clinical procedures.This Project has been partially supported by Portuguese national funds via Fundação para a Ciência e a Tecnologia—Ministério da Ciência, Tecnologia e Ensino Superior (FCT-MCTES), under Project 679 Research4Covid19, UIDB/04539/2020 and UIDP/04539/2020.info:eu-repo/semantics/publishedVersio

    Analysis of shear forces during mash disk formation

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    This report concerns a forming process in which mash is forced from a spreading manifold into moulds on a rotating drum, transported in the moulds underneath a surface held flush with the drum (the shoe), and ejected from the moulds. The quality of the final product is understood to be related to the shear stresses experienced by the mash in the moulds as it is transported under the shoe. We describe and analyse mathematical models of the forming process, focusing on the fluid mechanics of mash in a mould. We treat this as a driven cavity flow and obtain flow profiles, stress profiles, and expressions for the maximum shear stress for different rheological models of the mash (Newtonian fluid, power-law fluid, and Bingham plastic)

    Investigation of the Level of Knowledge in Different Countries about Edible Insects: Cluster Segmentation

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    This study aimed to investigate the level of knowledge about edible insects (EIs) in a sample of people from thirteen countries (Croatia, Greece, Latvia, Lebanon, Lithuania, Mexico, Poland, Portugal, Romania, Serbia, Slovenia, Spain, and Turkey). Data collection was based on a questionnaire survey applied through online tools between July and November 2021. For data analysis, techniques such as factor analysis, cluster analysis, and chi-square tests were used, with a significance level of 5%. A total of 27 items were used to measure knowledge on a five-point Likert scale. Applying factor analysis with principal components and Varimax rotation, a solution that explains about 55% of variance was obtained. This accounts for four factors that retained 22 of the 27 initial items: F1 = Sustainability (8 items), F2 = Nutrition (8 items), F3 = Production Factors (2 items), and F4 = Health Concerns (4 items). Internal consistency was evaluated through Cronbach’s alpha. The cluster analysis consisted of the application of hierarchical methods followed by k-means and produced three clusters (1—‘fearful’, 2—‘farming,’ and 3—‘ecological’ individuals). The characterisation of the clusters revealed that age did not influence cluster membership, while sex, education, country, living environment, professional area, and income all influenced the composition of the clusters. While participants from Mexico and Spain were fewer in the ‘fearful’ cluster, in those from Greece, Latvia, Lebanon, and Turkey, the situation was opposed. Participants from rural areas were mostly in cluster 2, which also included a higher percentage of participants with lower income. Participants from professional areas linked with biology, food, and nutrition were mostly in cluster 3. In this way, we concluded that the level of knowledge about EIs is highly variable according to the individual characteristics, namely that the social and cultural influences of the different countries lead to distinct levels of knowledge and interpretation of information, thus producing divergent approaches to the consumption of insects—some more reluctant and measuring possible risks. In contrast, others consider EIs a good and sustainable protein-food alternative.info:eu-repo/semantics/publishedVersio
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