The early clinical features of dengue in adults: challenges for early clinical diagnosis

Background

The emergence of dengue throughout the tropical world is affecting an increasing proportion of adult cases. The clinical features of dengue in different age groups have not been well examined, especially in the context of early clinical diagnosis.

Methodology/Principal Findings

We structured a prospective study of adults (≥18 years of age) presenting with acute febrile illness within 72 hours from illness onset upon informed consent. Patients were followed up over a 3–4 week period to determine the clinical outcome. A total of 2,129 adults were enrolled in the study, of which 250 (11.7%) had dengue. Differences in the rates of dengue-associated symptoms resulted in high sensitivities when the WHO 1997 or 2009 classification schemes for probable dengue fever were applied to the cohort. However, when the cases were stratified into age groups, fewer older adults reported symptoms such as myalgia, arthralgia, retro-orbital pain and mucosal bleeding, resulting in reduced sensitivity of the WHO classification schemes. On the other hand, the risks of severe dengue and hospitalization were not diminshed in older adults, indicating that this group of patients can benefit from early diagnosis, especially when an antiviral drug becomes available. Our data also suggests that older adults who present with fever and leukopenia should be tested for dengue, even in the absence of other symptoms.

Conclusion

Early clinical diagnosis based on previously defined symptoms that are associated with dengue, even when used in the schematics of both the WHO 1997 and 2009 classifications, is difficult in older adults.     

Environmental Profile of a Community's Health (EPOCH): An Ecometric Assessment of Measures of the Community Environment Based on Individual Perception

BACKGROUND: Public health research has turned towards examining upstream, community-level determinants of cardiovascular disease risk factors. Objective measures of the environment, such as those derived from direct observation, and perception-based measures by residents have both been associated with health behaviours. However, current methods are generally limited to objective measures, often derived from administrative data, and few instruments have been evaluated for use in rural areas or in low-income countries. We evaluate the reliability of a quantitative tool designed to capture perceptions of community tobacco, nutrition, and social environments obtained from interviews with residents in communities in 5 countries. METHODOLOGY/ PRINCIPAL FINDINGS: Thirteen measures of the community environment were developed from responses to questionnaire items from 2,360 individuals residing in 84 urban and rural communities in 5 countries (China, India, Brazil, Colombia, and Canada) in the Environmental Profile of a Community's Health (EPOCH) study. Reliability and other properties of the community-level measures were assessed using multilevel models. High reliability (>0.80) was demonstrated for all community-level measures at the mean number of survey respondents per community (n?=?28 respondents). Questionnaire items included in each scale were found to represent a common latent factor at the community level in multilevel factor analysis models. CONCLUSIONS/ SIGNIFICANCE: Reliable measures which represent aspects of communities potentially related to cardiovascular disease (CVD)/risk factors can be obtained using feasible sample sizes. The EPOCH instrument is suitable for use in different settings to explore upstream determinants of CVD/risk factors.     

Increased risk of cognitive and functional decline in patients with atrial fibrillation: results of the ONTARGET and TRANSCEND studies

Background:

The role of atrial fibrillation in cognitive impairment and dementia, independent of stroke, is uncertain. We sought to determine the association of atrial fibrillation with cognitive and physical impairment in a large group of patients at high cardiovascular risk.

Methods:

We conducted a post-hoc analysis of two randomized controlled trials involving 31 546 patients, the aims of which were to evaluate the efficacy of treatment with ramipril plus telmisartan (ONTARGET) or telmisartan alone (TRANSCEND) in reducing cardiovascular disease. We evaluated the cognitive function of participants at baseline and after two and five years using the Mini–Mental State Examination (MMSE). In addition, we recorded incident dementia, loss of independence in activities of daily living and admission to long-term care facilities. We used a Cox regression model adjusting for main confounders to determine the association between atrial fibrillation and our primary outcomes: a decrease of three or more points in MMSE score, incident dementia, loss of independence in performing activities of daily living and admission to long-term care.

Results:

We enrolled 31 506 participants for whom complete information on atrial fibrillation was available, 70.4% of whom were men. The mean age of participants was 66.5 years, and the mean baseline MMSE score was 27.7 (standard deviation 2.9) points. At baseline, 1016 participants (3.3%) had atrial fibrillation, with the condition developing in an additional 2052 participants (6.5%) during a median follow-up of 56 months. Atrial fibrillation was associated with an increased risk of cognitive decline (hazard ratio [HR] 1.14, 95% confidence interval [CI] 1.03–1.26), new dementia (HR 1.30, 95% CI 1.14–1.49), loss of independence in performing activities of daily living (HR 1.35, 95% CI 1.19–1.54) and admission to long-term care facilities (HR 1.53, 95% CI 1.31–1.79). Results were consistent among participants with and without stroke or receiving antihypertensive drugs.

Interpretation:

Cognitive and functional decline are important consequences of atrial fibrillation, even in the absence of overt stroke.A trial fibrillation is an important and modifiable cause of ischemic stroke, which may result in considerable physical and cognitive disability.¹ In addition, atrial fibrillation is associated with an increased risk of covert cerebral infarction, which is reported in about one-quarter of patients with atrial fibrillation who undergo magnetic resonance imaging of the brain.² Thus, atrial fibrillation may be an important determinant of cognitive and functional decline, even in the absence of clinical ischemic stroke. However, previous epidemiologic studies evaluating atrial fibrillation’s association with cognitive function have been inconsistent,^3–13 and very few have evaluated its association with functional outcomes.¹⁴A recent systematic review showed convincing evidence of an association between atrial fibrillation and dementia in patients with a history of stroke, but it concluded that there was considerable uncertainty of a link between atrial fibrillation and dementia in patients with no history of stroke.¹⁵ Large prospective cohort studies are required to determine a true association between atrial fibrillation and cognitive outcomes.In this study, we sought to determine the prospective association between atrial fibrillation and cognitive decline, loss of independence in activities of daily living and admission to long-term care facilities, using data from a large group of patients included in the ONTARGET and TRANSCEND trials.^16,17     

Sumoylation in Aspergillus nidulans: sumO inactivation, overexpression and live-cell imaging

Sumoylation, the reversible covalent attachment of small ubiquitin-like modifier (SUMO) peptides has emerged as an important regulator of target protein function. In Saccharomyces cerevisiae, but not in Schizosaccharyomes pombe, deletion of the gene encoding SUMO peptides is lethal. We have characterized the SUMO-encoding gene, sumO, in the filamentous fungus Aspergillus nidulans. The sumO gene was deleted in a diploid and sumODelta haploids were recovered. The mutant was viable but exhibited impaired growth, reduced conidiation and self-sterility. Overexpression of epitope-tagged SumO peptides revealed multiple sumoylation targets in A. nidulans and SumO overexpression resulted in greatly increased levels of protein sumoylation without obvious phenotypic consequences. Using five-piece fusion PCR, we generated a gfp-sumO fusion gene expressed from the sumO promoter for live-cell imaging of GFP-SumO and GFP-SumO-conjugated proteins. Localization of GFP-SumO is dynamic, accumulating in punctate spots within the nucleus during interphase, lost at the onset of mitosis and re-accumulating during telophase.     

Genome Analysis of Staphylococcus agnetis,an Agent of Lameness in Broiler Chickens

Lameness in broiler chickens is a significant animal welfare and financial issue. Lameness can be enhanced by rearing young broilers on wire flooring. We have identified Staphylococcus agnetis as significantly involved in bacterial chondronecrosis with osteomyelitis (BCO) in proximal tibia and femorae, leading to lameness in broiler chickens in the wire floor system. Administration of S. agnetis in water induces lameness. Previously reported in some cases of cattle mastitis, this is the first report of this poorly described pathogen in chickens. We used long and short read next generation sequencing to assemble single finished contigs for the genome and a large plasmid from the chicken pathogen. Comparison of the S. agnetis genome to those of other pathogenic Staphylococci shows that S.agnetis contains a distinct repertoire of virulence determinants. Additionally, the S. agnetis genome has several regions that differ substantially from the genomes of other pathogenic Staphylococci. Comparison of our finished genome to a recent draft genome for a cattle mastitis isolate suggests that future investigations focus on the evolutionary epidemiology of this emerging pathogen of domestic animals.     

Reduction of Cell Lysate Viscosity during Processing of Poly(3-Hydroxyalkanoates) by Chromosomal Integration of the Staphylococcal Nuclease Gene in Pseudomonas putida

Poly(3-hydroxyalkanoates) (PHAs) are biodegradable thermoplastics which are accumulated by many bacterial species in the form of intracellular granules and which are thought to serve as reserves of carbon and energy. Pseudomonas putida accumulates a polyester, composed of medium-side-chain 3-hydroxyalkanoic acids, which has excellent film-forming properties. Industrial processing of PHA involves purification of the PHA granules from high-cell-density cultures. After the fermentation process, cells are lysed by homogenization and PHA granules are purified by chemical treatment and repeated washings to yield a PHA latex. Unfortunately, the liberation of chromosomal DNA during lysis causes a dramatic increase in viscosity, which is problematic in the subsequent purification steps. Reduction of the viscosity is generally achieved by the supplementation of commercially available nuclease preparations or by heat treatment; however, both procedures add substantial costs to the process. As a solution to this problem, a nuclease-encoding gene from Staphylococcus aureus was integrated into the genomes of several PHA producers. Staphylococcal nuclease is readily expressed in PHA-producing Pseudomonas strains and is directed to the periplasm, and occasionally to the culture medium, without affecting PHA production or strain stability. During downstream processing, the viscosity of the lysate from a nuclease-integrated Pseudomonas strain was reduced to a level similar to that observed for the wild-type strain after treatment with commercial nuclease. The nuclease gene was also functionally integrated into the chromosomes of other PHA producers, including Ralstonia eutropha.