Epidemiological Questions Research Articles

Lower urinary tract symptoms against the background of benign prostatic hyperplasia (LUTS/BPH) and testosterone deficiencyare there any links? General questions of terminology, methodology and age epidemiology

Lower urinary tract symptoms against the background of benign prostatic hyperplasia (LUTS/BPH) and testosterone deficiencyare there any links? General questions of terminology, methodology and age epidemiology

Genomic Epidemiology as a Public Health Tool to Combat Mosquito-Borne Virus Outbreaks.

Next-generation sequencing technologies, exponential increases in the availability of virus genomic data, and ongoing advances in phylogenomic methods have made genomic epidemiology an increasingly powerful tool for public health response to a range of mosquito-borne virus outbreaks. In this review, we offer a brief primer on the scope and methods of phylogenomic analyses that can answer key epidemiological questions during mosquito-borne virus public health emergencies. We then focus on case examples of outbreaks, including those caused by dengue, Zika, yellow fever, West Nile, and chikungunya viruses, to demonstrate the utility of genomic epidemiology to support the prevention and control of mosquito-borne virus threats. We extend these case studies with operational perspectives on how to best incorporate genomic epidemiology into structured surveillance and response programs for mosquito-borne virus control. Many tools for genomic epidemiology already exist, but so do technical and nontechnical challenges to advancing their use. Frameworks to support the rapid sharing of multidimensional data and increased cross-sector partnerships, networks, and collaborations can support advancement on all scales, from research and development to implementation by public health agencies.

Progress Toward Global Eradication of Dracunculiasis - January 2018-June 2019.

Dracunculiasis (also known as Guinea worm disease) is caused by the parasite Dracunculus medinensis and is acquired by drinking water containing copepods (water fleas) infected with D. medinensis larvae. The worm typically emerges through the skin on a lower limb approximately 1 year after infection, resulting in pain and disability (1). There is no vaccine or medicine to treat the disease; eradication efforts rely on case containment* to prevent water contamination and other interventions to prevent infection, including health education, water filtration, chemical treatment of unsafe water with temephos (an organophosphate larvicide to kill copepods), and provision of safe drinking water (1,2). In 1986, with an estimated 3.5 million cases† occurring each year in 20 African and Asian countries§ (3), the World Health Assembly called for dracunculiasis elimination (4). The global Guinea Worm Eradication Program (GWEP), led by The Carter Center and supported by the World Health Organization (WHO), CDC, the United Nations Children's Fund, and other partners, began assisting ministries of health in countries with dracunculiasis. This report, based on updated health ministry data, describes progress to eradicate dracunculiasis during January 2018-June 2019 and updates previous reports (2,4,5). With only five countries currently affected by dracunculiasis (Angola, Chad, Ethiopia, Mali, and South Sudan), achievement of eradication is within reach, but it is challenged by civil unrest, insecurity, and lingering epidemiologic and zoologic questions.

Identifying People with Dementia in Electronic Primary Care Records in the UK

Abstract Background Many epidemiological questions need to be answered regarding dementia, including the causes, prognosis, comorbidities, and treatment of the condition and complications. A routine electronic primary care dataset provides a way of investigating some of the complicated factors with rich information. However, there has been concern regarding whether dementia is recorded well enough. Methods This study has therefore explored this by conducting a systematic review to understand how dementia has been identified previously in primary care databases in the UK, and added to this by exploring additional terms and symptoms, and medications that might be helpful in identifying people with dementia. The study estimated the prevalence and incidence rates of dementia in The Health Improvement Network (THIN) database and compared with other longitudinal studies using the comprehensive list of diagnostic codes. Results The estimated incidence rates per 1,000 person-years for the 60+ age group who had any of the first diagnosis among the Quality Outcomes Framework (QOF) defined codes, Other diagnoses, Dementia symptoms and Prescribed medications were 2.5, 4.7, and 15.9 in 1995, 2004, and 2015 respectively. The estimated prevalence were 2.8, 3.2, and 10.2 in 1995, 2004, and 2015 respectively. Conclusions The codes related to dementia symptoms (represented by mini-mental state examination, the six item cognitive impairment test, referral to memory clinic and behaviour assessment) seem to cover a broad definition of dementia or pre-existing dementia population in the UK primary care records. At least, using of the Other diagnoses (represented by dementia annual review, senile/presenile dementia and dementia monitoring) in addition to the QOF defined codes, and Prescribed medications were evidenced that will not missing out a number of people with dementia. Key messages The codes related to dementia symptoms seem to cover a broad definition of dementia or pre-existing dementia population in electronic primary care records in the UK. Nevertheless, the codes about non-specific or temporary symptoms may need to be used carefully as it is possible for memory or cognitive function to be impaired temporarily due to other factors.

Detection of Fluorescent Powders and Their Effect on Survival and Recapture of Aedes aegypti (Diptera: Culicidae).

The use of insect markers, such as fluorescent powders, is a useful tool for studying ecological and epidemiological questions. Evaluating their effect on vectors of human disease agents, such as the invasive mosquito vector Aedes aegypti (Linnaeus), is crucial for their practical and reliable use, especially in parameters linked to the risk of disease transmission such as adult survival, dispersal, and host-seeking. Seven fluorescent powders (Hercules Radiant, DayGlo (DG), Risk Reactor (RR), and Angstrom Technologies), applied externally on cohorts of Ae. aegypti female mosquitoes, were tested to determine their impact on survival and recapture by baited mosquito traps, and their detectability after being exposed to controlled laboratory and semifield environments. There were no significant differences in survival among marked and unmarked females across all powders. Marked females were significantly less likely to be captured in baited traps relative to unmarked females, except for one of the DG powders. All females remained visibly marked on five parts of their body for 30 d (under both environments), except for one of the RR powders. The tested powders and application method are suitable for tracking mosquitoes throughout most of their lives under different environments, without significantly affecting their survival, but with potential impact on recapture by baited traps, possibly due to effects on senses or other physiological traits.

Development of a Multilocus sequence typing (MLST) scheme for Pan-Leishmania

Since the description of the Leishmania genus, its identification and organization have been a challenge. A high number of molecular markers have been developed to resolve phylogenetic differences at the species level and for addressing key epidemiological and population genetics questions. Based on Multilocus enzyme electrophoresis (MLEE), Multilocus sequence typing (MLST) schemes have been developed using different gene candidates. From 38 original gene targets proposed by other authors, 27 of them were chosen. In silico selection was made by analyzing free access genomic sequence data of 33 Leishmania species, one Paraleishmania representative, and one outgroup, in order to select the best 15 loci. De novo amplifications and primers redesign of these 15 genes were analyzed over a panel of 20 reference strains and isolates. Phylogenetic analysis was made at every step. Two MLST schemes were selected. The first one was based on the analysis of three-gene fragments, and it is suitable for species assignment as well as basic phylogenetic studies. By the addition of seven-genes, an approach based on the analysis of ten-gene fragments was also proposed. This is the first work that two optimized MLST schemes have been suggested, validated against a phylogenetically diverse panel of Leishmania isolates. MLST is potentially a powerful phylogenetic approach, and most probably the new gold standard for Leishmania spp. characterization.

Analysis of anticholinergic and sedative medicine effects on physical function, cognitive function, appetite and frailty: a cross-sectional study in Australia

ObjectiveTo test the association between use of medicines with anticholinergic or sedative properties and physical function, cognitive function, appetite and frailty.Design, setting and participantsThis cross-sectional study analysed baseline data collected...

Untangling the dynamics of persistence and colonization in microbial communities

A central goal of community ecology is to infer biotic interactions from observed distributions of co-occurring species. Evidence for biotic interactions, however, can be obscured by shared environmental requirements, posing a challenge for statistical inference. Here, we introduce a dynamic statistical model, based on probit regression, that quantifies the effects of spatial and temporal covariance in longitudinal co-occurrence data. We separate the fixed pairwise effects of species occurrences on persistence and colonization rates, a potential signal of direct interactions, from latent pairwise correlations in occurrence, a potential signal of shared environmental responses. We first validate our modeling framework with several simulation studies. Then, we apply the approach to a pressing epidemiological question by examining how human papillomavirus (HPV) types coexist. Our results suggest that while HPV types respond similarly to common host traits, direct interactions are sparse and weak, so that HPV type diversity depends largely on shared environmental drivers. Our modeling approach is widely applicable to microbial communities and provides valuable insights that should lead to more directed hypothesis testing and mechanistic modeling.

Interpretation of Whole-Genome Sequencing for Enteric Disease Surveillance and Outbreak Investigation.

The routine use of whole-genome sequencing (WGS) as part of enteric disease surveillance is substantially enhancing our ability to detect and investigate outbreaks and to monitor disease trends. At the same time, it is revealing as never before the vast complexity of microbial and human interactions that contribute to outbreak ecology. Since WGS analysis is primarily used to characterize and compare microbial genomes with the goal of addressing epidemiological questions, it must be interpreted in an epidemiological context. In this article, we identify common challenges and pitfalls encountered when interpreting sequence data in an enteric disease surveillance and investigation context, and explain how to address them.

Dashboards as strategy to integrate multiple data streams for real time surveillance

Dashboards as strategy to integrate multiple data streams for real time surveillance

Quantification of Facial Traits.

Measuring facial traits by quantitative means is a prerequisite to investigate epidemiological, clinical, and forensic questions. This measurement process has received intense attention in recent years. We divided this process into the registration of the face, landmarking, morphometric quantification, and dimension reduction. Face registration is the process of standardizing pose and landmarking annotates positions in the face with anatomic description or mathematically defined properties (pseudolandmarks). Morphometric quantification computes pre-specified transformations such as distances. Landmarking: We review face registration methods which are required by some landmarking methods. Although similar, face registration and landmarking are distinct problems. The registration phase can be seen as a pre-processing step and can be combined independently with a landmarking solution. Existing approaches for landmarking differ in their data requirements, modeling approach, and training complexity. In this review, we focus on 3D surface data as captured by commercial surface scanners but also cover methods for 2D facial pictures, when methodology overlaps. We discuss the broad categories of active shape models, template based approaches, recent deep-learning algorithms, and variations thereof such as hybrid algorithms. The type of algorithm chosen depends on the availability of pre-trained models for the data at hand, availability of an appropriate landmark set, accuracy characteristics, and training complexity. Quantification: Landmarking of anatomical landmarks is usually augmented by pseudo-landmarks, i.e., indirectly defined landmarks that densely cover the scan surface. Such a rich data set is not amenable to direct analysis but is reduced in dimensionality for downstream analysis. We review classic dimension reduction techniques used for facial data and face specific measures, such as geometric measurements and manifold learning. Finally, we review symmetry registration and discuss reliability.

Using GIS to Address Epidemiologic Research Questions

GIS provide us with a view of human health that cannot be obtained by other methods. The review considers recent uses of GIS to address epidemiologic questions by taking into account their spatial dimensions, highlighting the most commonly adopted methods and current trends. Methods for geocoding individual health data vary by place depending on the databases available and are not always described in sufficient detail. Open and proprietary online geocoding services are becoming more widely used, but they pose issues for health research. Spatial scan statistics have been joined by statistics measuring spatial autocorrelation as key methods for detecting clusters. Numerous studies revealing significant global and local patterns in health conditions are leading to increased interest in methods, such as geographically weighted regression, to explore spatially varying relationships between factors and outcomes. The software packages for clustering and geographically weighted regression analyses are generally available in free downloadable packages. Health research using these methods is now being conducted in every region of the world, but much of this work appears outside mainstream epidemiology journals. The spatial data handling capabilities of GIS have made it possible to manage and analyze health data in new ways. Technological change affecting how health researchers acquire and process the digital spatial data required to use GIS to answer epidemiologic questions presents challenges for the future.

Prevalence of Foot Pain Across an International Consortium of Population-Based Cohorts.

ObjectiveDespite the potential burden of foot pain, some of the most fundamental epidemiologic questions surrounding the foot remain poorly explored. The prevalence of foot pain has proven to be difficult to compare across existing studies due to variations in case definitions. The objective of this study was to investigate the prevalence of foot pain in several international population‐based cohorts using original data and to explore differences in the case definitions used.MethodsFoot pain variables were examined in 5 cohorts: the Chingford 1000 Women Study, the Johnston County Osteoarthritis Project, the Framingham Foot Study, the Clinical Assessment Study of the Foot, and the North West Adelaide Health Study. One question about foot pain was chosen from each cohort based on its similarity to the American College of Rheumatology pain question.ResultsThe precise definition of foot pain varied between the cohorts. The prevalence of foot pain ranged from 13% to 36% and was lowest in the cohort in which the case definition specific to pain was used, compared to the 4 remaining cohorts in which a definition included components of pain, aching, or stiffness. Foot pain was generally more prevalent in women and obese individuals and generally increased with age, with the prevalence being much lower in younger participants (ages 20–44 years).ConclusionFoot pain is common and is associated with female sex, older age, and obesity. Estimates of the prevalence of foot pain are likely to be affected by the case definition used. Therefore, in future population studies, the use of consistent measures of data collection must be considered.

PO 8446 COLLABORATIVE TUBERCULOSIS RESEARCH AGENDA AT KEMRI CENTER FOR GLOBAL HEALTH RESEARCH, KISUMU, KENYA

BackgroundDeveloping countries grapple with inadequate funding amidst high burden of diseases. Africa is home to 9 of the 22 countries with a high tuberculosis (TB) burden and to 29 of the 41 countries with a high TB-HIV burden. Kenya is among the high TB and high TB-HIV burden countries. The Western Kenya region has the highest burden of TB and HIV. North-South partnerships are pivotal in ameliorating funding gaps in clinical research.MethodsWhile optimising existing infrastructure and organising programme support (i.e sensitisation and awareness creation, leading to study participant recruitment), from 2005 to date we conducted with multiple North-South collaborators capacity strengthening, TB prevalence survey, observational studies, operational research, and vaccine and drug trials.ResultsTB prevalence survey showed 600 cases per 100,000 population, TB epidemiological studies among adolescents and infants yielded 680 and 900/100,000 population respectively while 2 TB vaccine trials among infants and adults were conducted in Siaya. Three TB drug trials and a TB patient observational cum bio-bank study were concluded in Kisumu. KEMRI TB laboratory was upgraded from BSL2 to BSL3, was ISO-accredited in 2013, renewed in 2015 and 2017 and supports TB programme health facilities with retreatment specimens, supervision and mentorship. Over 25 operational TB studies grouped into community and case detection (increasing case detection), diagnostic and molecular (new diagnostic methods) and epidemiology studies (testing and monitoring cohorts for epidemiological questions) were implemented. Five PhDs, 9 Master’s, 2 Postgraduate Diplomas, 6 Bachelor’s degrees and 10 Diplomas have been supported. Siaya clinical research center was built while in Kisumu an adolescent clinic was constructed. This work involved 18 northern and 26 southern partners. Over 35 publications have been published out of these collaborations.ConclusionNorth-South collaborations provided funding, expertise and resources to harness research capacity of KEMRI; hence the need to foster a global networking culture.

Secondary Rhinoplasty: Aesthetic and Functional Concerns.

Aesthetic and functional concerns, especially after multiple revision rhinoplasties, continue to provide a challenge even for the experienced surgeon. This study aimed to report the results in terms of "secondary rhinoplasty," performed by the senior author after previous rhinoplasty. This descriptive prospective study was carried on 150 patients with surgical indication of secondary rhinoplasty and they were asked to fill out the questionnaire divided into 3 parts: overall epidemiological questions, questions of patients' aesthetic and functional complaints, and objective evaluation by the surgeon. The nasal problems in the upper and middle regions were divided into high or low, broad or narrow, crooked, irregularity of nasal bridge, or other alterations. The patients included in the study had surgical programming of secondary rhinoplasty, with mandatory aesthetic and optional functional purposes, having previous rhinoplasty with the same or different surgeon. There were 136 females and 14 males with the mean age of 31.52 (6.36) years. The most common complaints were related to the nose tip with 123 cases included deviated tip and pinched (bilateral) with 25.3%, 30.7%, and 25.3%, middle nose with 78 cases included mid vault deviation, inverted V, and polly beak with 31.3%, 18%, and 9.3%, and upper nasal region with 69 cases included dorsum irregularity and wide dorsum with the rates of 22.7% and 16.7%, respectively; respiratory problem was reported in 13 cases. Unilateral or bilateral twisting at the nasal tip had the highest percentages, and the lowest incidence was in relation to the complaints of the upper nasal part.

An Optimized Microsatellite Scheme for Assessing Populations of Xanthomonas phaseoli pv. manihotis.

Diverse molecular markers have been used to analyze the genetic diversity of plant pathogens. Compared with traditional fingerprinting methods, multiple loci variable number of tandem repeat analyses (MLVAs) have gained importance recently due to their reproducibility, high discriminatory power, ease of performance, low cost, and throughput potential. These characteristics are desirable for continuous pathogen monitoring, especially for pathogens with relatively low genetic diversity, and for disease epidemiology studies. Genetic diversity studies of Xanthomonas phaseoli pv. manihotis, which is the causal agent of cassava bacterial blight, have shown variability and changes in the bacterial population over time. Thus, an easy and fast method needs to be developed to type populations of this pathogen in different countries of the world, especially on small scales. In this study, we developed an MLVA scheme to analyze X. phaseoli pv. manihotis variability on a local scale. The MLVA-15 scheme comprises 15 variable number of tandem repeat loci grouped into four multiplex polymerase chain reaction pools. We showed that the MLVA-15 scheme had slightly higher discriminatory ability at the locality level when compared with amplified fragment length polymorphisms. The MLVA-15 scheme allowed for an accurate determination of the number of genotypes in the sample and showed reproducibility and portability. Additionally, this scheme could be used to analyze numerous strains in a reasonable timeframe. The MLVA-15 scheme was highly specific to X. phaseoli but up to eight tandem repeat loci could be amplified from other Xanthomonas spp. Finally, we assessed the utility of the scheme for analyses of X. phaseoli pv. manihotis genetic variability in the Colombian Caribbean region. MLVA-15 distinguished 88.9% of the haplotypes in our sample. Strains originating from the same field and isolated at the same time could be discriminated. In this study, the advantages of the MLVA-15 scheme targeting 6- or 7-bp repeats were demonstrated. Moreover, this scheme was a fast method that was appropriate for routine monitoring of X. phaseoli pv. manihotis populations on a local scale and, thus, was useful for addressing epidemiological questions.

Genomic and epidemiological insights into chlamydial epitheliocystis

Chlamydiae are obligate intracellular bacteria with highly reduced genomes, reflective of their abilities to sequester nutrients from the host. The host range of this phylum far exceeds that described for the Chlamydia genus which encompasses terrestrial animals; however, much of this diversity is uncultivated. Of particular evolutionary significance are members of the earliest diverging family, Candidatus Parilichlamydiaceae, comprising only uncultivated species associated with the fish gill disease, epitheliocystis. Epitheliocystis poses a significant threat to aquaculture industries globally. Due to the lack of culture systems for Ca. Parilichlamydiaceae, little is known about their biology, which also imposes further limitations on answering epidemiological questions. Gill extracts from three Chlamydiales-positive Australian aquaculture species were subject to DNA preparation to deplete host DNA and enrich microbial DNA, prior to metagenome sequencing. We obtained three metagenome-assembled Ca. Parilichlamydiaceae genomes from three different host species, and conducted functional genomics comparisons with diverse members of the phylum. Using these genomes, we developed a novel Ca. Parilichlamydia carangidicola-specific multi locus sequence analysis (MLSA) scheme to investigate genetic diversity in this species Genomic analysis revealed highly reduced genomes (∼0.8 Mbp) that share 342 orthologs with other chlamydial families, with a notable reduction in genes for synthesis of nucleotides and amino acids. MLSA revealed a high level of genetic diversity of Ca. P. carangidicola, with 20 genotypes distributed among 29 samples from four populations within the same aquaculture facility. Culture-independent genomics has provided an unprecedented insight into chlamydial evolution, pathogenicity and epidemiology. This approach could be adapted for further genomic epidemiological investigations.;

Phylogenetic relationship of Ornithobacterium rhinotracheale isolated from poultry and diverse avian hosts based on 16S rRNA and rpoB gene analyses

BackgroundOrnithobacterium (O.) rhinotracheale is an emerging bacterial pathogen in poultry and not fully understood to date. Because of its importance particularly for the global turkey meat industry, reliable diagnostic and characterization methods are needed for early treatment and in future for better vaccine production. The host range of birds infected by O. rhinotracheale or carrying the bacterium in their respiratory tract has constantly increased raising important epidemiological and taxonomic questions for a better understanding of its diversity, ecology and transmission cycles. The purpose of this study was to introduce partial rpoB gene sequencing for O. rhinotracheale into routine diagnostics to differentiate strains isolated from poultry and more diverse avian hosts (i.e., birds of prey, corvids and pigeons) and to compare phylogenetic relationships with results from 16S rRNA gene analysis and multilocus sequence typing (MLST).ResultsPartial 16S rRNA gene analysis revealed a high level of homogeneity among the 65 investigated O. rhinotracheale sequences with similarity values ranging from 98.6 to 100% between sequences from non-galliform and poultry species. The corresponding rpoB gene sequences were heterogeneous and ranged in their similarity values from 85.1 to 100%. The structure of the rpoB tree was in strong correlation with previous MLST results revealing three main clusters A (poultry and birds of prey), B (poultry, birds of prey and corvids) and C (pigeons), which were clearly separated from each other.ConclusionsBy using partial sequences from a single gene, the rpoB gene analysis is in good agreement with MLST results with a slight decrease in resolution to distinguish more similar strains. The present results provide strong evidence that traditional phenotypic and genetic methods may not properly represent the heterogeneous group of bacteria classified as O. rhinotracheale. From housekeeping gene analyses, it is very likely that the genus Ornithobacterium includes additional species and partial rpoB gene sequencing can be recommended as fast, cost-effective and readily available method to identify strains and differentiate between O. rhinotracheale and Ornithobacterium-like bacteria.

Maximising mosquito collections from barrier screens: the impacts of physical design and operation parameters

BackgroundTraditional methods for collecting outdoor resting mosquitoes are generally inefficient with relatively low numbers caught per unit effort. The barrier screen, designed to intercept mosquitoes as they fly between areas where blood meals are obtained and oviposition sites where eggs are laid, was developed in 2013 as a novel method of sampling outdoor mosquito populations. Barrier screens do not use an odorant lure and are thus a non-mechanical, simple, low maintenance and passive sampling method for use, even in isolated locations.MethodsTo maximise mosquito collections from barrier screens, multiple Latin square 3 × 3 experiments were conducted in Smithfield, Queensland, Australia. Parameters of barrier screens were varied including the effects of construction materials (net weight and colour), screen design and frequency of inspections.ResultsSignificantly more mosquitoes were collected on simple dark coloured screens of 50% or 70% shading weight with collections every 30 min. Sixty percent of mosquitoes were found on barrier screens within 60 cm of the ground.ConclusionsThe barrier screen is a relatively new adaptable tool that can answer a number of behavioural, ecological and epidemiological questions relevant for the surveillance and basic understanding of the movement and resting habits of mosquitoes by sex or physiological status. This method has demonstrated robustness in collecting a wide range of mosquito species as well as flexibility in where barrier screens can be deployed to explore mosquito movements within rural and peri-domestic environments.

Simulation and analysis of HIV-AIDS dynamics

One of the most intriguing questions in mathematical epidemiology are how can one efficiently control and prevent the propagation of a disease. The problem of disease modelling, simulation and control becomes even more fascinating if we look at various risk groups. Referring to HIV-AIDS disease, it is worldwide agreed that the HIV virus seemingly knows when it should attack the body such as to develop AIDS disease. The fundamental question is therefore related to the time and location of such process to happen. To answer to this question, we study a model of propagation of HIV-AIDS in a given population. The AIDS disease is hardly easier to understand than HIV propagation dynamic, but fortunately, we can simplify the system even further by studying the susceptible and infected population dynamics in their behaviour in isolation and/or interaction. Finally, we develop a simulation model based on observed behaviours of susceptible and infected populations. This allows us to test our ideas of how the HIV virus develops into the AIDS disease within the highly controlled environment of computer simulation. Based on these insights, we can suggest new experiments on the actual system and update our models accordingly.