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Search Results: 1 - 10 of 300731 matches for " Ken J. Forbes "
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The Heterogeneity, Distribution, and Environmental Associations of Borrelia burgdorferi Sensu Lato, the Agent of Lyme Borreliosis, in Scotland
Marianne C. James,Lucy Gilbert,Alan S. Bowman,Ken J. Forbes
Frontiers in Public Health , 2014, DOI: 10.3389/fpubh.2014.00129
Abstract: Lyme borreliosis is an emerging infectious human disease caused by the Borrelia burgdorferi sensu lato complex of bacteria with reported cases increasing in many areas of Europe and North America. To understand the drivers of disease risk and the distribution of symptoms, which may improve mitigation and diagnostics, here we characterize the genetics, distribution, and environmental associations of B. burgdorferi s.l. genospecies across Scotland. In Scotland, reported Lyme borreliosis cases have increased almost 10-fold since 2000 but the distribution of B. burgdorferi s.l. is so far unstudied. Using a large survey of over 2200 Ixodes ricinus tick samples collected from birds, mammals, and vegetation across 25 sites we identified four genospecies: Borrelia afzelii (48%), Borrelia garinii (36%), Borrelia valaisiana (8%), and B. burgdorferi sensu stricto (7%), and one mixed genospecies infection. Surprisingly, 90% of the sequence types were novel and, importantly, up to 14% of samples were mixed intra-genospecies co-infections, suggesting tick co-feeding, feeding on multiple hosts, or multiple infections in hosts. B. garinii (hosted by birds) was considerably more genetically diverse than B. afzelii (hosted by small mammals), as predicted since there are more species of birds than small mammals and birds can import strains from mainland Europe. Higher proportions of samples contained B. garinii and B. valaisiana in the west, while B. afzelii and B. garinii were significantly more associated with mixed/deciduous than with coniferous woodlands. This may relate to the abundance of transmission hosts in different regions and habitats. These data on the genetic heterogeneity within and between Borrelia genospecies are a first step to understand pathogen spread and could help explain the distribution of patient symptoms, which may aid local diagnosis. Understanding the environmental associations of the pathogens is critical for rational policy making for disease risk mitigation and land management.
Operationalising Factors That Explain the Emergence of Infectious Diseases: A Case Study of the Human Campylobacteriosis Epidemic
Norval J. C. Strachan, Ovidiu Rotariu, Marion MacRae, Samuel K. Sheppard, Alison Smith-Palmer, John Cowden, Martin C. J. Maiden, Ken J. Forbes
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079331
Abstract: A framework of general factors for infectious disease emergence was made operational for Campylobacter utilising explanatory variables including time series and risk factor data. These variables were generated using a combination of empirical epidemiology, case-case and case-control studies, time series analysis, and microbial sub-typing (source attribution, diversity, genetic distance) to unravel the changing/emerging aetiology of human campylobacteriosis. The study focused on Scotland between 1990–2012 where there was a 75% increase in reported cases that included >300% increase in the elderly and 50% decrease in young children. During this period there were three phases 1990–2000 a 75% rise and a 20% fall to 2006, followed by a 19% resurgence. The rise coincided with expansions in the poultry industry, consumption of chicken, and a shift from rural to urban cases. The post-2000 fall occurred across all groups apart from the elderly and coincided with a drop of the prevalence of Campylobacter in chicken and a higher proportion of rural cases. The increase in the elderly was associated with uptake of proton pump inhibitors. During the resurgence the increase was predominantly in adults and the elderly, again there was increasing use of PPIs and high prevalences in chicken and ruminants. Cases associated with foreign travel during the study also increased from 9% to a peak of 16% in 2006 before falling to an estimated 10% in 2011, predominantly in adults and older children. During all three periods source attribution, genetic distance, and diversity measurements placed human isolates most similar to those in chickens. A combination of emergence factors generic for infectious diseases were responsible for the Campylobacter epidemic. It was possible to use these to obtain a putative explanation for the changes in human disease and the potential to make an informed view of how incidence rates may change in the future.
Geographic determinants of reported human Campylobacter infections in Scotland
Paul R Bessell, Louise Matthews, Alison Smith-Palmer, Ovidiu Rotariu, Norval JC Strachan, Ken J Forbes, John M Cowden, Stuart WJ Reid, Giles T Innocent
BMC Public Health , 2010, DOI: 10.1186/1471-2458-10-423
Abstract: Data on 33,967 confirmed Campylobacter infections in mainland Scotland between 2000 and 2006 (inclusive) that were spatially referenced to the postcode sector level were analysed. Risk factors including the Carstairs index of social deprivation, the easting and northing of the centroid of the postcode sector, measures of livestock density by species and population density were tested in univariate screening using a non-spatial generalised linear model. The NHS Health Board of the case was included as a random effect in this final model. Subsequently, a spatial generalised linear mixed model (GLMM) was constructed and age-stratified sensitivity analysis was conducted on this model.The spatial GLMM included the protective effects of the Carstairs index (relative risk (RR) = 0.965, 95% Confidence intervals (CIs) = 0.959, 0.971) and population density (RR = 0.945, 95% CIs = 0.916, 0.974. Following stratification by age group, population density had a significant protective effect (RR = 0.745, 95% CIs = 0.700, 0.792) for those under 15 but not for those aged 15 and older (RR = 0.982, 95% CIs = 0.951, 1.014). Once these predictors have been taken into account three NHS Health Boards remain at significantly greater risk (Grampian, Highland and Tayside) and two at significantly lower risk (Argyll and Ayrshire and Arran).The less deprived and children living in rural areas are at the greatest risk of being reported as a case of Campylobacter infection. However, this analysis cannot differentiate between actual risk and heterogeneities in individual reporting behaviour; nevertheless this paper has demonstrated that it is possible to explain the pattern of reported Campylobacter infections using both social and environmental predictors.Infection with bacteria of Campylobacter spp is the leading cause of human bacterial gastroenteritis in most developed countries [1]. In Scotland in 2006 there were 95.3 reported cases per 100,000 [2], although this figure is likely to represent
Using sequence data to identify alternative routes and risk of infection: a case-study of campylobacter in Scotland
Paul R Bessell, Ovidiu Rotariu, Giles T Innocent, Alison Smith-Palmer, Norval JC Strachan, Ken J Forbes, John M Cowden, Stuart WJ Reid, Louise Matthews
BMC Infectious Diseases , 2012, DOI: 10.1186/1471-2334-12-80
Abstract: C. jejuni samples from animal and environmental sources and from reported human cases confirmed between June 2005 and September 2006 were typed using MLST. The STRUCTURE software was used to assign the specific sequence types of the sporadic human cases to a particular source. We then used mixed case-case logistic regression analysis to compare the risk factors for being infected with C. jejuni from different sources.A total of 1,599 (46.3%) cases were assigned to poultry, 1,070 (31.0%) to ruminant and 67 (1.9%) to wild bird sources; the remaining 715 (20.7%) did not have a source that could be assigned with a probability of greater than 0.95. Compared to ruminant sources, cases attributed to poultry sources were typically among adults (odds ratio (OR) = 1.497, 95% confidence intervals (CIs) = 1.211, 1.852), not among males (OR = 0.834, 95% CIs = 0.712, 0.977), in areas with population density of greater than 500 people/km2 (OR = 1.213, 95% CIs = 1.030, 1.431), reported in the winter (OR = 1.272, 95% CIs = 1.067, 1.517) and had undertaken recent overseas travel (OR = 1.618, 95% CIs = 1.056, 2.481). The poultry assigned strains had a similar epidemiology to the unassigned strains, with the exception of a significantly higher likelihood of reporting overseas travel in unassigned strains.Rather than estimate relative risks for acquiring infection, our analyses show that individuals acquire C. jejuni infection from different sources have different associated risk factors. By enhancing our ability to identify at-risk groups and the times at which these groups are likely to be at risk, this work allows public health messages to be targeted more effectively. The rapidly increasing capacity to conduct genetic typing of pathogens makes such traced epidemiological analysis more accessible and has the potential to substantially enhance epidemiological risk factor studies.Epidemiological risk factor analyses are used to identify factors that influence the risk of individuals ac
Evolution of an Agriculture-Associated Disease Causing Campylobacter coli Clade: Evidence from National Surveillance Data in Scotland
Samuel K. Sheppard,John F. Dallas,Daniel J. Wilson,Norval J. C. Strachan,Noel D. McCarthy,Keith A. Jolley,Frances M. Colles,Ovidiu Rotariu,Iain D. Ogden,Ken J. Forbes,Martin C. J. Maiden
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015708
Abstract: The common zoonotic pathogen Campylobacter coli is an important cause of bacterial gastroenteritis worldwide but its evolution is incompletely understood. Using multilocus sequence type (MLST) data of 7 housekeeping genes from a national survey of Campylobacter in Scotland (2005/6), and a combined population genetic-phylogenetics approach, we investigated the evolutionary history of C. coli. Genealogical reconstruction of isolates from clinical infection, farm animals and the environment, revealed a three-clade genetic structure. The majority of farm animal, and all disease causing genotypes belonged to a single clade (clade 1) which had comparatively low synonymous sequence diversity, little deep branching genetic structure, and a higher number of shared alleles providing evidence of recent clonal decent. Calibration of the rate of molecular evolution, based on within-species genetic variation, estimated a more rapid rate of evolution than in traditional estimates. This placed the divergence of the clades at less than 2500 years ago, consistent with the introduction of an agricultural niche having had an effect upon the evolution of the C. coli clades. Attribution of clinical isolate genotypes to source, using an asymmetric island model, confirmed that strains from chicken and ruminants, and not pigs or turkeys, are the principal source of human C. coli infection. Taken together these analyses are consistent with an evolutionary scenario describing the emergence of agriculture-associated C. coli lineage that is an important human pathogen.
Elucidating the Aetiology of Human Campylobacter coli Infections
Francois Roux, Emma Sproston, Ovidiu Rotariu, Marion MacRae, Samuel K. Sheppard, Paul Bessell, Alison Smith-Palmer, John Cowden, Martin C. J. Maiden, Ken J. Forbes, Norval J. C. Strachan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064504
Abstract: There has been little research on the determinants of Campylobacter coli infection, despite its contributing up to 10% of human Campylobacter infections. A case-control and two case-case study methods explored the aetiology of C. coli over a one year period across Scotland. The case-control multivariate model found an increased risk of C. coli infection in people older than 19 years (O.R. = 3.352), and during the summer months (O.R. = 2.596), while residing in an urban area decreased the risk (O.R. = 0.546). The first case-case study compared C. coli and C. jejuni cases and also showed a higher risk of C. coli during the summer (O.R. = 1.313) and in people older than 19 years (O.R. = 0.791). Living in an urban area was associated with a reduced risk of infection (O.R. = 0.769). Multi-locus sequence typing (MLST) indicated that sheep and chicken C. coli sequence types (STs) were most frequently found in humans whilst those from cattle and pigs were rarer. MLST diversity was high in isolates from pigs and chicken, intermediate in human isolates, and low in ruminant isolates. The second case-case study used MLST data to ascribe putative sources of infection to the cases. The putative source for 40% of cases was chicken, with 60% acquired from other sources (ruminants 54% and pigs 6%). The case-case analysis also showed that female gender was a risk factor (O.R. = 1.940), which may be explained by females being more likely to prepare poultry in the home. These findings indicate differences between the aetiology of C. coli and C. jejuni infections: this should be taken into account by public health professionals when developing strategies to reduce the burden of human campylobacteriosis.
Interaction Propositions: A Comparison of “Dramaturgical Analysis” and “Exchange Theory,” the Micro Sociological Explanations of Face-to-Face Communication Proposed by Erving Goffman and George C. Homans
J Forbes Farmer
Journal of Society and Communication , 2012,
Abstract: This article is an investigation into some aspects of the communication-focused exchange theory as proposed by George C. Homans and the dramaturgical analysis of Erving Goffman. By presenting evidence from the original writings of these “contemporary” social theorists, the author suggests that Goffman’s symbolic interactionism could be assimilated into Homans’ propositions, or laws, and gereralizations about communication, interactions and encounters.
A Proof of Concept Study on Cortisol Response to Three Different Educational Environs (Alone, Same-Sex, and Mixed-Sex)  [PDF]
Sean A. Forbes, Svetlana Chesser, Anthony J. Guarino
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.44A002
This proof of concept study assessed student cortisol levels under three environs: 1) alone; 2) same-sex setting; and 3) mixed-sex setting after completing a cognitive task. The results indicated that both males and females demonstrated increased levels in the same-sex environs compared to the other environs. The relevant issue for educators is whether this response is adaptive. Implications of these findings are discussed.
Growth and Toxin Production by Microcystis Aeruginosa PCC 7806 (Kutzing) Lemmerman at Elevated Salt Concentrations  [PDF]
Ken Black, Mete Yilmaz, Edward J. Phlips
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.26077
Abstract: One of the most common and widespread bloom-forming cyanobacteria associated with toxin production is Microcystis aeruginosa (Kutzing) Lemmerman. While normally associated with fresh water environments, this toxigenic species has been observed at bloom concentrations in a number of major estuaries worldwide. This study examined the effect of salinity on growth and toxin production by M. aeruginosa strain PCC 7806 under controlled laboratory conditions. Salt concentrations above 12.6 ppt resulted in total cessation of growth. Toxin production was similarly affected, with cultures grown in salt concentrations of 4.6 ppt and above yielding less toxin than the control after 20 days of culture. Toxin concentrations after 20 days of culture were 40% of the control at 4.6 ppt. The relative proportion of extracellular to intracellular toxin increased over time in cultures with salt concentrations greater than 4.6 ppt. Extracellular toxins persisted in the media long after the cessation of growth. The results suggest that the influence of M. aeruginosa and/or its toxins can extend well out into estuarine environments under the influence of significant freshwater inputs.
A constructive approach for discovering new drug leads: Using a kernel methodology for the inverse-QSAR problem
William WL Wong, Forbes J Burkowski
Journal of Cheminformatics , 2009, DOI: 10.1186/1758-2946-1-4
Abstract: In this paper, we describe the reversibility of our previously reported descriptor, the vector space model molecular descriptor (VSMMD) based on a vector space model that is suitable for kernel studies in QSAR modeling. Our inverse-QSAR approach can be described using five steps: (1) generate the VSMMD for the compounds in the training set; (2) map the VSMMD in the input space to the kernel feature space using an appropriate kernel function; (3) design or generate a new point in the kernel feature space using a kernel feature space algorithm; (4) map the feature space point back to the input space of descriptors using a pre-image approximation algorithm; (5) build the molecular structure template using our VSMMD molecule recovery algorithm.The empirical results reported in this paper show that our strategy of using kernel methodology for an inverse-Quantitative Structure-Activity Relationship is sufficiently powerful to find a meaningful solution for practical problems.The structural conformation and physicochemical properties of both the ligand and its receptor site determine the level of binding affinity that is observed in such an interaction. If the structural properties of the receptor site are known (for example, there is crystallographic data) then techniques involving approximations of potential functions can be applied to estimate or at least compare binding affinities of various ligands [1]. When this information is sparse or not available, as is the case for many membrane proteins, it becomes necessary to estimate affinities using only the properties of the ligand. This ligand-based prediction strategy is often used in applications such as virtual screening of molecular databases in a drug discovery procedure.In a more general setting we strive to establish the quantitative dependency between the molecular properties of a ligand and its binding affinity. To restate this goal using current terminology: we want to analyze the Quantitative Structure-Activity
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