342 research outputs found
Inferring metabolic mechanisms of interaction within a defined gut microbiota
The diversity and number of species present within microbial communities create the potential for a multitude of interspecies metabolic interactions. Here, we develop, apply, and experimentally test a framework for inferring metabolic mechanisms associated with interspecies interactions. We perform pairwise growth and metabolome profiling of co-cultures of strains from a model mouse microbiota. We then apply our framework to dissect emergent metabolic behaviors that occur in co-culture. Based on one of the inferences from this framework, we identify and interrogate an amino acid cross-feeding interaction and validate that the proposed interaction leads to a growth benefit in vitro. Our results reveal the type and extent of emergent metabolic behavior in microbial communities composed of gut microbes. We focus on growth-modulating interactions, but the framework can be applied to interspecies interactions that modulate any phenotype of interest within microbial communities
Mosquito Magnet ® traps as a potential means of monitoring blackflies of medical and veterinary importance
Mosquito Magnet® traps, deployed in widespread parts of England as part of nationwide mosquito surveillance projects, also caught blackflies. As many as 1242 blackflies were caught in a trapping session lasting 4 days. Principal among the species caught were Simulium equinum, Simulium lineatum and Simulium ornatum s.l. As S. ornatum s.l. is a vector that transmits Onchocerca linealis to cattle and S. equinum is responsible for dermatitis ('sweet itch') in cattle and horses, it is suggested that Mosquito Magnet® traps could be used to monitor and partially control these pests, as well as nuisance anthropophilic blackflies such as Simulium posticatum that can cause simuliidosis in southern England
Finite to infinite steady state solutions, bifurcations of an integro-differential equation
We consider a bistable integral equation which governs the stationary
solutions of a convolution model of solid--solid phase transitions on a circle.
We study the bifurcations of the set of the stationary solutions as the
diffusion coefficient is varied to examine the transition from an infinite
number of steady states to three for the continuum limit of the
semi--discretised system. We show how the symmetry of the problem is
responsible for the generation and stabilisation of equilibria and comment on
the puzzling connection between continuity and stability that exists in this
problem
Rat Stem-Cell Factor Induces Splenocytes Capable Of Regenerating The Thymus
Cytokine regulation of prethymic T-lymphoid progenitor-cell proliferation and/or
differentiation has not been well-defined, although much is known of cytokine
regulation of hemopoietic stem- and progenitor-cell development. Here we use a
recently identified hemopoietic growth factor, stem-cell factor (SCF) (a form of the c-kit
ligand), and a transplant model of thymocyte regeneration to assess the effect of SCF on
the in vivo generation of prethymic, thymocyte progenitor-cell activity. We show that
recombinant rat SCF (rrSCF164 administered to weanling rats selectively induces an
increase in thymocyte progenitor activity in the spleens of treated rats as compared to
rats treated with vehicle, polyethylene glycol (PEG)-conjugated rat albumin, or
recombinant human granulocyte colony-stimulating factor (rhG-CSF). These data
demonstrate that administration of SCF in vivo affects extrathymic-origin thymocyte
regenerating cells and may influence, directly or indirectly, early prethymic stages of T-cell
lymphopoiesis in addition to its known effect on early stages of myelopoiesis and
erythropoiesis
Discovery of a single male Aedes aegypti (L.) in Merseyside, England
© The Author(s). 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The file attached is the published (publishers PDF) version of the article
The passive surveillance of ticks using companion animal electronic health records
Ticks represent a large global reservoir of zoonotic disease. Current surveillance systems can be time and labour intensive. We propose that the passive surveillance of companion animal electronic health records (EHRs) could provide a novel methodology for describing temporal and spatial tick activity. A total of 16 58 857 EHRs were collected over a 2-year period (31 March 2014 and 29 May 2016) from companion animals attending a large sentinel network of 192 veterinary clinics across Great Britain (the Small Animal Veterinary Surveillance Network - SAVSNET). In total, 2180 EHRs were identified where a tick was recorded on an animal. The relative risk of dogs presenting with a tick compared with cats was 0·73 (95% confidence intervals 0·67-0·80). The highest number of tick records were in the south central regions of England. The presence of ticks showed marked seasonality with summer peaks, and a secondary smaller peak in autumn for cats; ticks were still being found throughout most of Great Britain during the winter. This suggests that passive surveillance of companion animal EHRs can describe tick activity temporally and spatially in a large cohort of veterinary clinics across Great Britain. These results and methodology could help inform veterinary and public health messages as well as increase awareness of ticks and tick-borne diseases in the general population
Modelling the strategies for age specific vaccination scheduling during influenza pandemic outbreaks
Finding optimal policies to reduce the morbidity and mortality of the ongoing
pandemic is a top public health priority. Using a compartmental model with age
structure and vaccination status, we examined the effect of age specific
scheduling of vaccination during a pandemic influenza outbreak, when there is a
race between the vaccination campaign and the dynamics of the pandemic. Our
results agree with some recent studies on that age specificity is paramount to
vaccination planning. However, little is known about the effectiveness of such
control measures when they are applied during the outbreak. Comparing five
possible strategies, we found that age specific scheduling can have a huge
impact on the outcome of the epidemic. For the best scheme, the attack rates
were up to 10% lower than for other strategies. We demonstrate the importance
of early start of the vaccination campaign, since ten days delay may increase
the attack rate by up to 6%. Taking into account the delay between developing
immunity and vaccination is a key factor in evaluating the impact of
vaccination campaigns. We provide a general framework which will be useful for
the next pandemic waves as well
Diverse tick-borne microorganisms identified in free-living ungulates in Slovakia
Background: Free-living ungulates are hosts of ixodid ticks and reservoirs of tick-borne microorganisms in central Europe and many regions around the world. Tissue samples and engorged ticks were obtained from roe deer, red deer, fallow deer, mouflon, and wild boar hunted in deciduous forests of south-western Slovakia. DNA isolated from these samples was screened for the presence of tick-borne microorganisms by PCR-based methods. Results: Ticks were found to infest all examined ungulate species. The principal infesting tick was Ixodes ricinus, identified on 90.4% of wildlife, and included all developmental stages. Larvae and nymphs of Haemaphysalis concinna were feeding on 9.6% of wildlife. Two specimens of Dermacentor reticulatus were also identified. Ungulates were positive for A. phagocytophilum and Theileria spp. Anaplasma phagocytophilum was found to infect 96.1% of cervids, 88.9% of mouflon, and 28.2% of wild boar, whereas Theileria spp. was detected only in cervids (94.6%). Importantly, a high rate of cervids (89%) showed mixed infections with both these microorganisms. In addition to A. phagocytophilum and Theileria spp., Rickettsia helvetica, R. monacensis, unidentified Rickettsia sp., Coxiella burnetii, "Candidatus Neoehrlichia mikurensis", Borrelia burgdorferi (s.l.) and Babesia venatorum were identified in engorged I. ricinus. Furthermore, A. phagocytophilum, Babesia spp. and Theileria spp. were detected in engorged H. concinna. Analysis of 16S rRNA and groEL gene sequences revealed the presence of five and two A. phagocytophilum variants, respectively, among which sequences identified in wild boar showed identity to the sequence of the causative agent of human granulocytic anaplasmosis (HGA). Phylogenetic analysis of Theileria 18S rRNA gene sequences amplified from cervids and engorged I. ricinus ticks segregated jointly with sequences of T. capreoli isolates into a moderately supported monophyletic clade. Conclusions: The findings indicate that free-living ungulates are reservoirs for A. phagocytophilum and Theileria spp. and engorged ixodid ticks attached to ungulates are good sentinels for the presence of agents of public and veterinary concern. Further analyses of the A. phagocytophilum genetic variants and Theileria species and their associations with vector ticks and free-living ungulates are required.Fil: Kazimírová, Mária. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Hamšíková, Zuzana. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Spitalská, Eva. Slovak Academy of Sciences. Institute of Virology. Biomedical Research Center,; EslovaquiaFil: Minichová, Lenka. Slovak Academy of Sciences. Institute of Virology. Biomedical Research Center,; EslovaquiaFil: Mahríková, Lenka. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Caban, Radoslav. Široká ; EslovaquiaFil: Sprong, Hein. National Institute for Public Health and Environment.Laboratory for Zoonoses and Environmental Microbiology; Países BajosFil: Fonville, Manoj. National Institute for Public Health and Environment.Laboratory for Zoonoses and Environmental Microbiology; Países BajosFil: Schnittger, Leonhard. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kocianová, Elena. Slovak Academy of Sciences. Institute of Virology. Biomedical Research Center,; Eslovaqui
Recognizing speculative language in biomedical research articles: a linguistically motivated perspective
We explore a linguistically motivated approach to the problem of recognizing speculative language (“hedging”) in biomedical research articles. We describe a method, which draws on prior linguistic work as well as existing lexical resources and extends them by introducing syntactic patterns and a simple weighting scheme to estimate the speculation level of the sentences. We show that speculative language can be recognized successfully with such an approach, discuss some shortcomings of the method and point out future research possibilities.
Surveillance of Ixodes ricinus ticks (Acari: Ixodidae) in Iceland
Background: Ixodes ricinus is a three-host tick, a principal vector of Borrelia burgdorferi (s.l.) and one of the main
vectors of tick-borne encephalitis (TBE) virus. Iceland is located in the North Atlantic Ocean with subpolar oceanic
climate. During the past 3–4 decades, average temperature has increased, supporting more favourable conditions
for ticks. Reports of I. ricinus have increased in recent years. If these ticks were able to establish in a changing
climate, Iceland may face new threats posed by tick-borne diseases.
Methods: Active field surveillance by tick flagging was conducted at 111 sites around Iceland from August 2015 to
September 2016. Longworth mammal traps were used to trap Apodemus sylvaticus in southwestern and southern
Iceland. Surveillance on tick importation by migratory birds was conducted in southeastern Iceland, using bird nets
and a Heligoland trap. Vulpes lagopus carcasses from all regions of the country were inspected for ticks. In addition,
existing and new passive surveillance data from two institutes have been merged and are presented. Continental
probability of presence models were produced. Boosted Regression Trees spatial modelling methods and its
predictions were assessed against reported presence.
Results: By field sampling 26 questing I. ricinus ticks (7 males, 3 females and 16 nymphs) were collected from
vegetation from three locations in southern and southeastern Iceland. Four ticks were found on migratory birds at their
arrival in May 2016. A total of 52 A. sylvaticus were live-trapped but no ticks were found nor on 315 V. lagopus carcasses.
Passive surveillance data collected since 1976, reports further 214 I. ricinus ticks from 202 records, with an
increase of submissions in recent years. The continental probability of presence model correctly predicts
approximately 75% of the recorded presences, but fails to predict a fairly specific category of recorded
presence in areas where the records are probably opportunistic and not likely to lead to establishment.
Conclusions: To the best of our knowledge, this study represents the first finding of questing I. ricinus ticks
in Iceland. The species could possibly be established locally in Iceland in low abundance, although no
questing larvae have yet been detected to confirm established populations. Submitted tick records have
increased recently, which may reflect an increase in exposure, or in interest in ticks. Furthermore, the
amount of records on dogs, cats and humans indicate that ticks were acquired locally, presenting a local
biting risk. Tick findings on migratory birds highlight a possible route of importation. Obtaining questing
larvae is now a priority to confirm that I. ricinus populations are established in Iceland. Further surveys on
wild mammals (e.g. Rangifer tarandus), livestock and migratory birds are recommended to better understand
their role as potential hosts for I. ricinus.Work was carried out under VectorNet, a European network for sharing data on the geographic distribution of arthropod vectors, transmitting human and animal disease agents (framework contract OC/EFSA/AHAW/2013/02-FWC1) funded by the European Food Safety Authority (EFSA) and the European Centre for Disease prevention and Control (ECDC). JM is also partly funded by the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Environmental Change and Health at the London School of Hygiene & Tropical Medicine in partnership with Public Health England (PHE), and in collaboration with the University of Exeter, University College London, and the Met Office; and partly funded by the NIHR HPRU on Emerging Infections and Zoonoses at the University of Liverpool in partnership with PHE and Liverpool School of Tropical Medicine.Peer Reviewe
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