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1.
Background and objectivesThe prevalence of anaemia is an important health indicator, although there is little rigorous information gathered on the elderly population, particularly in those over 80 years old. The same criteria that are used in the general population are often used to define anaemia in the elderly. The epidemiological data collected by the WHO in 1968 (that have been used to generalise this criteria), did not include the population over 65 years-old.Two objectives are established, which includes a critical review of the available evidence on whether the criteria used to define anaemia in the adult population can be extrapolated to the elderly, and a review of publications on the prevalence of anaemia in the elderly over 80 years-old.Material and methodsA systematic bibliographic search was performed on the established objectives.ResultsAlthough the WHO criteria, based on data from 1968, are widely used, other possible cut-off points have been proposed for elderly people. A total of 20 studies were found that were conducted in North America and Europe, with only 70,000 patients, and different age criteria. The prevalence of anaemia ranges between 3% and 63%, depending on the diagnostic criteria, age, and whether they were institutionalised or not.ConclusionsAnaemia is a very prevalent disease in elderly patients. The collection of large databases is necessary to determine more adequate diagnostic criteria.  相似文献   

2.
Mosquito-borne diseases contribute significantly to the global disease burden. High-profile elimination campaigns are currently underway for many parasites, e.g., Plasmodium spp., the causal agent of malaria. Sustaining momentum near the end of elimination programs is often difficult to achieve and consequently quantitative tools that enable monitoring the effectiveness of elimination activities after the initial reduction of cases has occurred are needed. Documenting progress in vector-borne disease elimination is a potentially important application for the theory of critical transitions. Non-parametric approaches that are independent of model-fitting would advance infectious disease forecasting significantly. In this paper, we consider compartmental Ross-McDonald models that are slowly forced through a critical transition through gradually deployed control measures. We derive expressions for the behavior of candidate indicators, including the autocorrelation coefficient, variance, and coefficient of variation in the number of human cases during the approach to elimination. We conducted a simulation study to test the performance of each summary statistic as an early warning system of mosquito-borne disease elimination. Variance and coefficient of variation were highly predictive of elimination but autocorrelation performed poorly as an indicator in some control contexts. Our results suggest that tipping points (bifurcations) in mosquito-borne infectious disease systems may be foreshadowed by characteristic temporal patterns of disease prevalence.  相似文献   

3.
The objectives of this trial were to evaluate and compare the test characteristics of a number of indirect tests of bacteriological status of the milk from goats and sheep and to assess the affect of varying levels of prevalence of infection on the performance of those tests.The somatic cell count, California mastitis test (CMT) score, electrical impedance and the bacteriological status of 220 and 262 milk samples from the glands of lactating dairy goats and sheep, respectively, were determined. The sensitivity and specificity of indirect tests in predicting the bacteriological status were compared by analyzing the areas under the receiver operating characteristic curve and calculating the likelihood ratio at various cut-off values.Bacteria were isolated from 17.7 and 4.6% of glands from goats and sheep, respectively. Somatic cell count was a better predictor of bacteriological status than either the CMT score or impedance in both goats and sheep. However, knowledge of the CMT score in both sheep and goats and the impedance in goats increases the likelihood of predicting the presence of a bacterial pathogen compared to no testing at all (P<0.05). Knowledge of the age and days postpartum of the animals at the time of testing did not increase the probability that infection status could be predicted. Variation in cut-off levels to predict infection status reported in the literature may be due to variation in the prevalence of infection in the populations studied. Use of likelihood ratio allows comparison of tests over a range of prevalence’s as likelihood ratios are independent of prevalence. The prevalence of infection within a herd should be considered when selecting a cut-off value for indirect testing for the presence of bacteria in milk of small ruminants.  相似文献   

4.

Introduction

Previous comparison studies of the Kalon and HerpeSelect 2 ELISA IgG assays on sub-Saharan samples have found differences in the sensitivity and specificity of these assays. Using longitudinal samples from an HIV prevention study, we compared both assays and determined the HSV-2 prevalence and incidence in a South African young female population at elevated risk of acquiring HIV.

Methods

Samples at baseline were tested in both assays using the manufacturers’ guidelines (cut-off > 1.10). When non-reactive in one assay, the final visit samples were tested to determine the incidence rate. Using correlation and regression analyses, the intra- and inter-assay variabilities were assessed.

Results

The prevalence rate was 41.1% and 44.9% for Kalon and HerpeSelect using the manufacturer guidelines, respectively. Agreement between the two tests were high (kappa = 0.92). The original optical density values of both assays were highly correlated (R = 0.94), but the calibrator and correspondingly cut-off index values differed between the assays. Lowering the index value cut-off for the Kalon assay by 40% (to 0.66) resulted in a HSV-2 prevalence of 43.2%, and increased agreement between the assays (to kappa = 0.96). The incidence rate was 16.3/100 Person Years using the lower cut-off for the Kalon assay.

Discussion

In this longitudinal study, we showed that the performance of the two assays was very similar. After lowering the cut-off for the Kalon assay to 0.66 early infections were detected without impairing its specificity. The prevalence and incidence rates are in line with previously described rates for sub-Saharan African cohorts.  相似文献   

5.

Background

Bovine tuberculosis (BTB) today primarily affects developing countries. In Africa, the disease is present essentially on the whole continent; however, little accurate information on its distribution and prevalence is available. Also, attempts to evaluate diagnostic tests for BTB in naturally infected cattle are scarce and mostly complicated by the absence of knowledge of the true disease status of the tested animals. However, diagnostic test evaluation in a given setting is a prerequisite for the implementation of local surveillance schemes and control measures.

Methodology/Principal Findings

We subjected a slaughterhouse population of 954 Chadian cattle to single intra-dermal comparative cervical tuberculin (SICCT) testing and two recently developed fluorescence polarization assays (FPA). Using a Bayesian modeling approach we computed the receiver operating characteristic (ROC) curve of each diagnostic test, the true disease prevalence in the sampled population and the disease status of all sampled animals in the absence of knowledge of the true disease status of the sampled animals. In our Chadian setting, SICCT performed better if the cut-off for positive test interpretation was lowered from >4 mm (OIE standard cut-off) to >2 mm. Using this cut-off, SICCT showed a sensitivity and specificity of 66% and 89%, respectively. Both FPA tests showed sensitivities below 50% but specificities above 90%. The true disease prevalence was estimated at 8%. Altogether, 11% of the sampled animals showed gross visible tuberculous lesions. However, modeling of the BTB disease status of the sampled animals indicated that 72% of the suspected tuberculosis lesions detected during standard meat inspections were due to other pathogens than Mycobacterium bovis.

Conclusions/Significance

Our results have important implications for BTB diagnosis in a high incidence sub-Saharan African setting and demonstrate the practicability of our Bayesian approach for diagnostic test evaluation.  相似文献   

6.
In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing a negative association, but no significant explanatory power was offered for PorTLS.  相似文献   

7.
There are 3 strains of Encephalitozoon cuniculi that occur in mammals. Strain III is associated with clinical disease in dogs, although some can be asymptomatic carriers and excrete spores in their urine. Several cases of human E. cuniculi infection caused by strain III have been observed in immunocompromised patients, indicating that E. cuniculi should be considered a zoonotic agent. Encephalitozoon cuniculi can cause fatal disease in maternally-infected or young dogs. Clinical signs in these animals included blindness, encephalitis, retarded growth rate, and nephritis. Encephalitozoon cuniculi has also been associated with primary renal failure in adult dogs. The present study used the direct agglutination test (DAT, cut-off 1:50) and the indirect fluorescent antibody test (IFAT, cut-off 1:10) to examine the prevalence of antibodies to E. cuniculi in dogs from Brazil and Colombia. Using the DAG, 31 (27.4%) of 113 dogs from Brazil and 47 (18.5%) of 254 dogs from Colombia were seropositive. Nine (14.3%) of 63 dogs from Brazil and 18 (35.3%) of the 51 dogs from Colombia were seropositive by indirect immunofluorescent antibody test. These results indicate that dogs from Brazil and Colombia are exposed to E. cuniculi.  相似文献   

8.
Definitions of epidemiological concepts regarding disease monitoring and surveillance can be found in textbooks on veterinary epidemiology. This paper gives a review of how the concepts: monitoring, surveillance, and disease control strategies are defined. Monitoring and surveillance systems (MO&SS) involve measurements of disease occurrence, and the design of the monitoring determines which types of disease occurrence measures can be applied. However, the knowledge of the performance of diagnostic tests (sensitivity and specificity) is essential to estimate the true occurrence of the disease. The terms, disease control programme (DCP) or disease eradication programme (DEP), are defined, and the steps of DCP/DEP are described to illustrate that they are a process rather than a static MO&SS.  相似文献   

9.
The early diagnosis and treatment of individuals harboring M. tuberculosis is key to ensuring the effectiveness of health programs aimed at the elimination of tuberculosis (TB). Monitoring for TB also has other important health care implications for the related immune pathology caused by the chronic inflammatory response to M. tuberculosis. Moreover, the recent introduction of biologic therapies for the treatment of several immune-mediated inflammatory diseases has shown unexpected high frequencies of reactivation of latent TB. The present cross-sectional study is aimed at estimating the prevalence of latent tuberculosis infection (LTBI) in different groups of subjects, either undergoing a routine program of screening for TB or a clinical monitoring of autoimmune or lung disorders, by analyzing their immune response in vitro to a pool of different M. tuberculosis antigens through an IFN-gamma-release assay (IGRA). We consecutively tested 1,644 subjects including health care workers (931), healthy immigrants from different countries (93), patients with a diagnosis of psoriasis (405), patients with lung inflammatory disease (60) or lung neoplasia (32) and a group of HIV-1 infected Italian subjects (120). The prevalence of IGRAs positive responses among health care workers was 8.9 percent. In comparison, significantly higher frequencies were found in healthy immigrant subjects (33.3%), similar to those found in inflammatory broncho-pneumopathies (34.5%) or lung cancer (29.6%). Interestingly, an unexpected high prevalence was also found in patients affected by psoriasis (18.0%), while HIV-infected subjects had values comparable to those of health care workers (10.8%). An age cut-off was determined and applied for each group by receiver operating characteristic (ROC) curves in order to perform the statistical analysis among age-comparable groups. Multivariate analysis showed that the age and clinical conditions such as having a diagnosis of psoriasis or a lung inflammatory disease were independent risk factors for developing an IGRA positive response. This study highlights an unprecedented high prevalence of IGRA positive responses among patients affected by psoriasis and emphasizes the need for a preliminary assessment of LTBI before the administration of any biologic therapy based on cytokine antagonists such as anti-TNF-alpha. Moreover, screening for LTBI should be routinely performed in the presence of a chronic pulmonary disease.  相似文献   

10.

Definitions of epidemiological concepts regarding disease monitoring and surveillance can be found in textbooks on veterinary epidemiology. This paper gives a review of how the concepts: monitoring, surveillance, and disease control strategies are defined. Monitoring and surveillance systems (MO&SS) involve measurements of disease occurrence, and the design of the monitoring determines which types of disease occurrence measures can be applied. However, the knowledge of the performance of diagnostic tests (sensitivity and specificity) is essential to estimate the true occurrence of the disease. The terms, disease control programme (DCP) or disease eradication programme (DEP), are defined, and the steps of DCP/DEP are described to illustrate that they are a process rather than a static MO&SS.

  相似文献   

11.
Human cytomegalovirus (HCMV) end-organ disease in solid-organ transplant recipients (SOTR) may be associated with either high or low HCMV load in blood. In transplantation Centers where the preemptive therapy approach is adopted, antiviral therapy of systemic HCMV infections is initiated upon reaching pre-determined cut-off levels of viral DNA in blood, whereas no guidelines are provided for local end-organ infection/disease. In the latter case, clinicians often start antiviral treatment without defining the etiology of local symptoms. Here, we describe 14 cases of SOTR, in which a documented HCMV end-organ disease was observed. Nine patients had a systemic viral load lower than the cut-off for preemptive therapy and were treated based on viral load of local HCMV disease. The remaining five patients had a systemic viral load greater than the preemptive therapy cut-off and were efficiently treated for both the systemic and the local HCMV disease. Thus, HCMV infection in the post-transplant period must be monitored virologically both in blood and locally. End-organ disease in preemptively treated patients, seems to be associated with lack of development (primary HCMV infection) or reconstitution (reactivated infection) of HCMV-specific CD4+ and CD8+ T-cell immunity or with its functional impairment.  相似文献   

12.
BackgroundWe sought to identify the distribution and cut-off value of the ‘homeostasis model assessment of insulin resistance’ (HOMA-IR) according to gender and menopausal status for metabolic syndrome in Koreans.MethodsData were from the Korean National Health and Nutrition Examination Survey in 2008–2010. The subjects included adults aged 20 years or older. We excluded participants who had diabetes or fasting serum glucose ≥ 7 mmol/L. Finally, 11,121 subjects (4,911 men, 3,597 premenopausal women, 2,613 postmenopausal women) were enrolled. The modified Adult Treatment Panel III criteria were used to define metabolic syndrome.ResultsThe mean HOMA-IR was 2.11 (2.07–2.15) for men, 2.0 (1.97–2.04) for premenopausal women, and 2.14 (2.2–2.19) for postmenopausal women. The first cut-off values in men, premenopausal women, and postmenopausal women were 2.23 (sensitivity 70.6%, specificity 66.9%), 2.39 (sensitivity 72.3%, specificity 76.4%), and 2.48 (sensitivity 51.9%, specificity 80.2%), respectively. Based on the first HOMA-IR cut-off value, the prevalence of metabolic syndrome was 22.9% in men, 13.7% in premenopausal women, and 51.6% in postmenopausal women. The second cut-off value was around 3.2 in all three groups. Based on the second HOMA-IR cut-off value, the prevalence of metabolic syndrome was 50.8% in men, 42.5% in premenopausal women, and 71.6% in postmenopausal women.ConclusionIn conclusion, the first cut-off values for HOMA-IR were 2.2–2.5 and the second cut-off value was 3.2 in Korea. The distribution of HOMA-IR showed differences according to gender and menopausal status. When we apply HOMA-IR, we should consider gender, menopausal status, and the prevalence of metabolic syndrome.  相似文献   

13.
To identify optimal cut-off points of fasting plasma glucose (FPG) for two-step strategy in screening abnormal glucose metabolism and estimating prevalence in general Chinese population. A population-based cross-sectional study was conducted on 7913 people aged 20 to 74 years in Harbin. Diabetes and pre-diabetes were determined by fasting and 2 hour post-load glucose from the oral glucose tolerance test in all participants. Screening potential of FPG, cost per case identified by two-step strategy, and optimal FPG cut-off points were described. The prevalence of diabetes was 12.7%, of which 65.2% was undiagnosed. Twelve percent or 9.0% of participants were diagnosed with pre-diabetes using 2003 ADA criteria or 1999 WHO criteria, respectively. The optimal FPG cut-off points for two-step strategy were 5.6 mmol/l for previously undiagnosed diabetes (area under the receiver-operating characteristic curve of FPG 0.93; sensitivity 82.0%; cost per case identified by two-step strategy ¥261), 5.3 mmol/l for both diabetes and pre-diabetes or pre-diabetes alone using 2003 ADA criteria (0.89 or 0.85; 72.4% or 62.9%; ¥110 or ¥258), 5.0 mmol/l for pre-diabetes using 1999 WHO criteria (0.78; 66.8%; ¥399), and 4.9 mmol/l for IGT alone (0.74; 62.2%; ¥502). Using the two-step strategy, the underestimates of prevalence reduced to nearly 38% for pre-diabetes or 18.7% for undiagnosed diabetes, respectively. Approximately a quarter of the general population in Harbin was in hyperglycemic condition. Using optimal FPG cut-off points for two-step strategy in Chinese population may be more effective and less costly for reducing the missed diagnosis of hyperglycemic condition.  相似文献   

14.
Disease monitoring and surveillance systems (MOSSs) have become one of the major components of veterinary activity. Such systems are used to assess the existing levels of prevalence, the effectiveness of control programmes and, after disease eradication, to document the continued absence of disease from a given region or zone. With decreasing disease or infection prevalence, traditional approaches become less reliable and increasingly costly. The objective of this work was to summarize and discuss methodological issues related to veterinary (animal health) MOSSs. There are considerable inconsistencies in the use of the terms 'monitoring' and 'surveillance'. Passive as well as active MOSS have their disadvantages when used for rare health-related events such as emerging and re-emerging diseases. There is a need for evaluation and improvement of these approaches. Integrated systems that call for the use of several parallel surveillance activities seem to be the favoured approach, and analytical methods to combine MOSS data from various sources into a population prevalence, or probability of disease freedom, are under development. The health and safety of the animal and human generations depends on our continuous ability to detect, monitor and control newly emerging or re-emerging livestock diseases and zoonoses rapidly. Uniform surveillance definitions, sound scientifically based approaches that use the resources and data available, and a pool of researchers and veterinary public health officials with sufficient training in epidemiology, are critically important to handle this challenging task.  相似文献   

15.
AIMS: To evaluate a conventional bacteriological test based on faecal culture and an indirect serum ELISA for detection of S. Dublin infected cattle. To compare the predictive values of the two tests in relation to the prevalence. METHODS AND RESULTS: A total of 4531 paired samples from cattle in 29 dairy herds were analysed for presence of S. Dublin bacteria in faeces and immunoglobulins directed against S. Dublin lipopolysaccharide in an indirect serum ELISA. Sensitivity and specificity were estimated at two ELISA cut-off values using a validation method based on latent class models, which presumably provides less biased results than traditional validation methods. Stratification of data into three age groups gave significantly better estimates of test performance of the ELISA. Receiver operating characteristic (ROC) curves were constructed for comparison of overall performance of the ELISA between the three age groups. The sensitivity of the faecal culture test was low (6-14%). ELISA appeared to have a higher validity for animals aged 100-299 days of age than older or younger animals. Overall, the negative predictive value of the ELISA was 2-10 times higher than for the faecal culture test at realistic prevalence of infection in the test population. CONCLUSIONS: The diagnostic sensitivity of the faecal culture test for detection of S. Dublin is poor, the specificity is 1. The superior sensitivity and negative predictive value of the serum ELISA makes this test preferable to faecal culture as an initial screening test and for certification of herds not infected with S. Dublin. SIGNIFICANCE AND IMPACT OF THE STUDY: A quantitative estimate of the sensitivity of a faecal culture test for S. Dublin in a general population was provided. ELISA was shown to be an appropriate alternative diagnostic test. Preferably, samples from animals aged 100-299 days of age should be used as these give the best overall performance of the ELISA. Plots of ROC curves and predictive values in relation to prevalence facilitates optimisation of the ELISA cut-off value.  相似文献   

16.
17.
A high efficient Supply Chain (SC) would bring great benefits to an enterprise such as integrated resources, reduced logistics costs, improved logistics efficiency and high quality of overall level of services. So it is important to research various methods, performance indicator systems and technology for evaluating, monitoring, predicting and optimizing the performance of a SC. In this paper, the existing performance indicator systems and methods are discussed and evaluated. Various nature-inspired algorithms are reviewed and their applications for SC Performance Evaluation (PE) are discussed. Then, a model is proposed and developed using 5 Dimensional Balanced Scorecard (5DBSC) and LMBP (Levenberg-Marquardt Back Propagation) neural network for SC PE. A program is written using Matlab tool box to implement the model based on the practical values of the 14 indicators of 5DBSC of a given previous period. This model can be used to evaluate, predict and optimize the performance of a SC. The analysis results of a case study of a company show that the proposed model is valid, reliable and effective. The convergence speed is faster than that in the previous work.  相似文献   

18.
Various innovative diagnostic methods for Alzheimer’s disease (AD) have been developed in view of the increasing preva-lence and consequences of later-life dementia. Biomarkers in cerebrospinal fluid (CSF) and blood for AD are primarily based on the detection of components derived from amyloid plaques and neurofibrillary tangles (NFTs). Published reports on CSF and blood biomarkers in AD indicate that although biomarkers in body fluids may be utilized in the clinical diagnosis of AD, there are no specific markers that permit accurate and reliable diagnosis of early-stage AD or the monitoring of disease pro-gression.  相似文献   

19.
Chronic kidney disease (CKD) is a progressive pathological condition marked by deteriorating renal function over time. Diagnostic of kidney disease depend on serum creatinine level and glomerular filtration rate which is detectable when kidney function become half. The detection of kidney damage in an early stage needs robust biomarkers. Biomarkers allow monitoring the disease progression at initial stages of disease. On the onset of impairment in cellular organization there is perturbation in signaling molecules which are either up-regulated or down-regulated and act as an indicator or biomarker of diseased stage. This review compiled the cell signaling of different kidney biomarkers associated with the onset of chronic kidney diseases. Delay in diagnosis of CKD will cause deterioration of nephron function which leads to End stage renal disease and at that point patients require dialysis or kidney transplant. Detailed information on the complex network in signaling pathway leading to a coordinated pattern of gene expression and regulation in CKD will undoubtedly provide important clues to develop novel prognostic and therapeutic strategies for CKD.  相似文献   

20.
Ultrasonography of the optic nerve sheath diameter (ONSD) is a non-invasive and rapid method that might be helpful in the identification of increased intracranial pressure (ICP). The use of an ONSD greater than 5 mm on ultrasound as an indicator of increased ICP in a Caucasian population has been studied. However, the cut-off point of this predictor in Chinese patients has not been established. Thus, we conducted this study to identify the ONSD criterion for the detection of elevated opening pressure on lumbar puncture (LP) in a Chinese population and to investigate the influencing factors. This study was a blind cross-sectional study. Patients who presented with suspected increased ICP were included. The opening pressure on LP of each participant was confirmed. We analyzed the clinical differences between the groups of patients with abnormal and normal opening pressures on LP. A receiver operating characteristic curve was constructed to determine the ONSD cut-off point for the identification of abnormal opening pressure on LP. In total, 279 patients were recruited, and 101 patients presented with elevated opening pressure on LP. ONSD was a significant independent predictor of elevated opening pressure on LP (p<0.001). However, no statistical significance was observed regarding the factors that might have affected this relationship including gender, age, body mass index, waistline, head circumference, hypertension and pathological subtype. The ONSD cut-off point for the identification of elevated opening pressure on LP was 4.1 mm; this cut-off yielded a sensitivity of 95% and a specificity of 92%. ONSD is a strong and accurate predictor of elevated opening pressure on LP. The cut-off point of this predictor in a Chinese population was remarkably lower than that found in a Caucasian population. Thus, ethnic differences should be noted when using the ONSD as an indicator of increased ICP.  相似文献   

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