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‣ Joint Modeling, Covariate Adjustment, and Interaction: Contrasting Notions in Risk Prediction Models and Risk Prediction Performance

Kerr, Kathleen F.; Pepe, Margaret S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/2011 Português
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Epidemiologic methods are well established for investigating the association of a predictor of interest and disease status in the presence of covariates also associated with disease. There is less consensus on how to handle covariates when the goal is to evaluate the increment in prediction performance gained by a new marker when a set of predictors already exists. We distinguish between adjusting for covariates and joint modeling of disease risk in this context. We show that adjustment versus joint modeling are distinct concepts, and we describe the specific conditions where they are the same. We also discuss the concept of interaction among variables and describe a notion of interaction that is relevant to prediction performance. We conclude with a discussion of the most appropriate methods for evaluating new biomarkers in the presence of existing predictors.

‣ Comparison of Address-based Sampling and Random-digit Dialing Methods for Recruiting Young Men as Controls in a Case-Control Study of Testicular Cancer Susceptibility

Clagett, Bartholt; Nathanson, Katherine L.; Ciosek, Stephanie L.; McDermoth, Monique; Vaughn, David J.; Mitra, Nandita; Weiss, Andrew; Martonik, Rachel; Kanetsky, Peter A.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
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Random-digit dialing (RDD) using landline telephone numbers is the historical gold standard for control recruitment in population-based epidemiologic research. However, increasing cell-phone usage and diminishing response rates suggest that the effectiveness of RDD in recruiting a random sample of the general population, particularly for younger target populations, is decreasing. In this study, we compared landline RDD with alternative methods of control recruitment, including RDD using cell-phone numbers and address-based sampling (ABS), to recruit primarily white men aged 18–55 years into a study of testicular cancer susceptibility conducted in the Philadelphia, Pennsylvania, metropolitan area between 2009 and 2012. With few exceptions, eligible and enrolled controls recruited by means of RDD and ABS were similar with regard to characteristics for which data were collected on the screening survey. While we find ABS to be a comparably effective method of recruiting young males compared with landline RDD, we acknowledge the potential impact that selection bias may have had on our results because of poor overall response rates, which ranged from 11.4% for landline RDD to 1.7% for ABS.

‣ Genotypic and Epidemiologic Trends of Norovirus Outbreaks in the United States, 2009 to 2013

Vega, Everardo; Barclay, Leslie; Gregoricus, Nicole; Shirley, S. Hannah; Lee, David; Vinjé, Jan
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /01/2014 Português
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Noroviruses are the leading cause of epidemic acute gastroenteritis in the United States. From September 2009 through August 2013, 3,960 norovirus outbreaks were reported to CaliciNet. Of the 2,895 outbreaks with a known transmission route, person-to-person and food-borne transmissions were reported for 2,425 (83.7%) and 465 (16.1%) of the outbreaks, respectively. A total of 2,475 outbreaks (62.5%) occurred in long-term care facilities (LTCF), 389 (9.8%) in restaurants, and 227 (5.7%) in schools. A total of 435 outbreaks (11%) were typed as genogroup I (GI) and 3,525 (89%) as GII noroviruses. GII.4 viruses caused 2,853 (72%) of all outbreaks, of which 94% typed as either GII.4 New Orleans or GII.4 Sydney. In addition, three non-GII.4 viruses, i.e., GII.12, GII.1, and GI.6, caused 528 (13%) of all outbreaks. Several non-GII.4 genotypes (GI.3, GI.6, GI.7, GII.3, GII.6, and GII.12) were significantly more associated with food-borne transmission (odds ratio, 1.9 to 7.1; P < 0.05). Patients in LTCF and people ≥65 years of age were at higher risk for GII.4 infections than those in other settings and with other genotypes (P < 0.05). Phylogeographic analysis identified three major dispersions from two geographic locations that were responsible for the GI.6 outbreaks from 2011 to 2013. In conclusion...

‣ Dietary assessment methods in epidemiologic studies

Shim, Jee-Seon; Oh, Kyungwon; Kim, Hyeon Chang
Fonte: Korean Society of Epidemiology Publicador: Korean Society of Epidemiology
Tipo: Artigo de Revista Científica
Publicado em 22/07/2014 Português
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Diet is a major lifestyle-related risk factor of various chronic diseases. Dietary intake can be assessed by subjective report and objective observation. Subjective assessment is possible using open-ended surveys such as dietary recalls or records, or using closed-ended surveys including food frequency questionnaires. Each method has inherent strengths and limitations. Continued efforts to improve the accuracy of dietary intake assessment and enhance its feasibility in epidemiological studies have been made. This article reviews common dietary assessment methods and their feasibility in epidemiological studies.

‣ The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted Human Immunodeficiency Virus (P2C2 HIV) Infection Study: Design and Methods

Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1996 Português
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The P2C2 HIV Study is a prospective natural history study initiated by the National Heart, Lung, and Blood Institute in order to describe the types and incidence of cardiovascular and pulmonary disorders that occur in children with vertically transmitted HIV infection (i.e., transmitted from mother to child in utero or perinatally). This article describes the study design and methods. Patients were recruited from five clinical centers in the United States. The cohort is composed of 205 infants and children enrolled after 28 days of age (Group I) and 612 fetuses and infants of HIV-infected mothers, enrolled prenatally (73%) or postnatally at age <28 days (Group II). The maternal-to-infant transmission rate in Group II was 17%. The HIV-negative infants in Group II (Group IIb) serves as a control group for the HIV-infected children (Group IIa). The cohort is followed at specified intervals for clinical examination, cardiac, pulmonary, immunologic, and infectious studies and for intercurrent illnesses. In Group IIa, the cumulative loss-to-follow-up rate at 3 years was 10.5%, and the 3-year cumulative mortality rate was 24.9%. The findings will be relevant to clinical and epidemiologic aspects of HIV infection in children.

‣ Age-Related Macular Degeneration and the Incidence of Cardiovascular Disease: A Systematic Review and Meta-Analysis

Wu, Juan; Uchino, Miki; Sastry, Srinivas M.; Schaumberg, Debra A.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
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Importance Research has indicated some shared pathogenic mechanisms between age-related macular degeneration (AMD) and cardiovascular disease (CVD). However, results from prior epidemiologic studies have been inconsistent as to whether AMD is predictive of future CVD risk. Objective: To systematically review population-based cohort studies of the association between AMD and risk of total CVD and CVD subtypes, coronary heart disease (CHD) and stroke. Data Sources A systematic search of the PubMed and EMBASE databases and reference lists of key retrieved articles up to December 20, 2012 without language restriction. Data Extraction Two reviewers independently extracted data on baseline AMD status, risk estimates of CVD and methods used to assess AMD and CVD. We pooled relative risks using random or fixed effects models as appropriate. Results: Thirteen cohort studies (8 prospective and 5 retrospective studies) with a total of 1,593,390 participants with 155,500 CVD events (92,039 stroke and 62,737 CHD) were included in this meta-analysis. Among all studies, early AMD was associated with a 15% (95% CI, 1.08–1.22) increased risk of total CVD. The relative risk was similar but not significant for late AMD (RR, 1.17; 95% CI, 0.98–1.40). In analyses restricted to the subset of prospective studies...

‣ Acid Suppression Therapy Does Not Predispose to Clostridium difficile Infection: The Case of the Potential Bias

Novack, Lena; Kogan, Slava; Gimpelevich, Larisa; Howell, Michael; Borer, Abraham; Kelly, Ciarán P.; Leffler, Daniel A.; Novack, Victor
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
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Objective: An adverse effect of acid-suppression medications on the occurrence of Clostridium difficile infection (CDI) has been a common finding of many, but not all studies. We hypothesized that association between acid-suppression medications and CDI is due to the residual confounding in comparison between patients with infection to those without, predominantly from non-tested and less sick subjects. We aimed to evaluate the effect of acid suppression therapy on incidence of CDI by comparing patients with CDI to two control groups: not tested patients and patients suspected of having CDI, but with a negative test. Methods: We conducted a case-control study of adult patients hospitalized in internal medicine department of tertiary teaching hospital between 2005–2010 for at least three days. Controls from each of two groups (negative for CDI and non-tested) were individually matched (1∶1) to cases by primary diagnosis, Charlson comorbidity index, year of hospitalization and gender. Primary outcomes were diagnoses of International Classification of Diseases (ICD-9)–coded CDI occurring 72 hours or more after admission. Results: Patients with CDI were similar to controls with a negative test, while controls without CDI testing had lower clinical severity. In multivariable analysis...

‣ Improving Health Service Delivery in Developing Countries : From Evidence to Action

Peters, David H.; El-Saharty, Sameh; Siadat, Banafsheh; Janovsky, Katja; Vujicic, Marko
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research
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Decision makers and the public are in need of information to guide their decisions about how to strengthen health services. This book pulls together available evidence concerning strategies to improve health services delivery in low- and middle-income countries (LMICs), using current methods to assemble a knowledge base and analyze the findings. It describes the results of reviews of such strategies, and how such strategies can produce gains for the poor. This type of information is intended to help decision makers in LMICs learn from others and from their own experiences, so that they may develop and implement strategies that will improve health services in their own setting. The book provides some suggestions for what works and how to improve implementation, as the evidence does not hold up for 'blueprint' planning. It finds that there are many ways that can succeed in improving health services. But not nearly enough attention has been paid to demonstrating how to improve services for the poor. Approaches that ask difficult questions, use information intelligently, and involve key stakeholders and institutions are critical to 'learning and doing' practices that underlie successful implementation of health services.

‣ An analysis of objective quality indicators on Year Book citations: implications for MEDLINE searchers.

Johnson, E D; McKinin, E J; Sievert, M E; Reid, J C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1997 Português
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PURPOSE: This study is an analysis of Mosby Year Book citations from Ovid Online's Comprehensive Core Medical Library (CCML). The purpose of this study was twofold: (1) to determine whether Year Book citations were more likely to be judged "key" than non-Year Book citations by clinicians; and (2) to determine whether the MEDLINE record of Year Book citations evaluated as key contained objective quality indicators that searchers might use to target key articles. BACKGROUND: As part of the MEDLINE/Full-Text Research Project, health care professionals evaluated search output from CCML on a five-point scale. The scale included the choice "key" for those items which the evaluator would not want to miss. Because the output contained items from the Year Book series, it was possible to determine whether the Year Book items were evaluated as key more frequently than expected. METHODS: This study analyzes the MEDLINE records corresponding to 110 references from the Mosby Year Book series evaluated as key by clinicians receiving search output from CCML. The records were examined for the presence of such searchable elements as Medical Subject Headings (MeSH) terms and publication types related to study design, evidence of research support, inclusion in the Abridged Index Medicus (AIM) subset...

‣ Canadian heart health surveys: a profile of cardiovascular risk. Survey methods and data analysis. Canadian Heart Health Surveys Research Group.

MacLean, D R; Petrasovits, A; Nargundkar, M; Connelly, P W; MacLeod, E; Edwards, A; Hessel, P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/06/1992 Português
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OBJECTIVE: To describe the methods used in nine provincial surveys carried out as part of the Canadian Heart Health Initiative. DESIGN: Population-based cross-sectional surveys, following a core standardized protocol, implemented by provincial departments of health in collaboration with Health and Welfare Canada. Data were obtained through a home interview and a clinic visit. A standard manual of field operations and standardized training procedures were used in all provinces. SETTING: Nine Canadian provinces during the period 1986 to 1990. PARTICIPANTS: A probability sample of 26,293 men and women aged 18 to 74 years was selected from the health insurance registries in each province. Over 30% of the participants had post-secondary education. About 50% were 18 to 34 years old. OUTCOME MEASURES: Data on sociodemographic characteristics, hypertensive and diabetic status, knowledge and awareness of the causes and consequences of cardiovascular disease and two blood pressure measurements were obtained in a home interview. During a clinic visit, data were collected on height, weight (waist and hip circumferences in four provinces), two blood pressure measures and a blood sample. Total plasma cholesterol, triglycerides and high- and low-density lipoprotein cholesterol were measured in the Lipid Research Laboratory...

‣ Snippets From the Past: The Evolution of Wade Hampton Frost's Epidemiology as Viewed From the American Journal of Hygiene/Epidemiology

Morabia, Alfredo
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
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Wade Hampton Frost, who was a Professor of Epidemiology at Johns Hopkins University from 1919 to 1938, spurred the development of epidemiologic methods. His 6 publications in the American Journal of Hygiene, which later became the American Journal of Epidemiology, comprise a 1928 Cutter lecture on a theory of epidemics, a survey-based study of tonsillectomy and immunity to Corynebacterium diphtheriae (1931), 2 papers from a longitudinal study of the incidence of minor respiratory diseases (1933 and 1935), an attack rate ratio analysis of the decline of diphtheria in Baltimore (1936), and a 1936 lecture on the age, time, and cohort analysis of tuberculosis mortality. These 6 American Journal of Hygiene /American Journal of Epidemiology papers attest that Frost's personal evolution mirrored that of the emerging “early” epidemiology: The scope of epidemiology extended beyond the study of epidemics of acute infectious diseases, and rigorous comparative study designs and their associated quantitative methods came to light.

‣ Local television news coverage of traumatic deaths and injuries

McArthur, David L; Magaña, Daniel; Peek-Asa, Corinne; Kraus, Jess F
Fonte: Copyright 2001 BMJ Publishing Group Publicador: Copyright 2001 BMJ Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /12/2001 Português
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Objective To assess how local television news programs' reporting of injuries and deaths from traumatic causes compares with coroners' records of deaths and the estimated incidence of injuries in the same geographic area during the same time. Methods Using epidemiologic methods, we identified the underlying cause of death or injury in each of 828 local television news stories broadcast in Los Angeles during late 1996 or early 1997 that concerned recent (<3 days) traumatic injuries or deaths in Los Angeles County. Odds ratios were computed using deaths by homicide or injuries sustained in assaults as the referent group. Results The number of persons depicted as dead amounted to 47.8% of the actual total number of traumatic deaths occurring in Los Angeles County during the study period. In contrast, the number depicted as injured represented only 3.4% of injuries due to traumatic causes. Both injuries and deaths due to fires, homicides, and legal interventions were proportionally well represented. However, injuries and deaths from accidental poisoning, falls, and suicide were significantly underrepresented. Conclusions Some types of events receive disproportionately more news coverage than others. Local television news tends strongly to present only those events concerned with death or injury that are visually compelling. We discuss reasons for concern about the effect that this form of information bias has on public understanding of health issues and possible counteractions that physicians can take.

‣ Preventing Cognitive Decline in Older African Americans with Mild Cognitive Impairment: Design and Methods of a Randomized Clinical Trial

Rovner, Barry W.; Casten, Robin J.; Hegel, Mark T.; Leiby, Benjamin E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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Mild Cognitive Impairment (MCI) affects 25% of older African Americans and predicts progression to Alzheimer's disease. An extensive epidemiologic literature suggests that cognitive, physical, and/or social activities may prevent cognitive decline. We describe the methods of a randomized clinical trial to test the efficacy of Behavior Activation to prevent cognitive decline in older African Americans with the amnestic multiple domain subtype of MCI. Community Health Workers deliver 6 initial in-home treatment sessions over 2-3 months and then 6 subsequent in-home booster sessions using language, materials, and concepts that are culturally relevant to older African Americans during this 24 month clinical trial. We are randomizing 200 subjects who are recruited from churches, senior centers, and medical clinics to Behavior Activation or Supportive Therapy, which controls for attention. The primary outcome is episodic memory as measured by the Hopkins Verbal Learning Test-Revised at baseline and at months 3, 12, 18, and 24. The secondary outcomes are general and domain-specific neuropsychological function, activities of daily living, depression, and quality-of-life. The negative results of recent clinical trials of drug treatments for MCI and Alzheimer's disease suggest that behavioral interventions may provide an alternative treatment approach to preserve cognition in an aging society.

‣ A prospective study of medical care utilization and morbidity in preschool children belonging to a prepaid group practice: background and methods.

Morgenstern, H.; Horwitz, S. M.; Berkman, L. F.
Fonte: Yale Journal of Biology and Medicine Publicador: Yale Journal of Biology and Medicine
Tipo: Artigo de Revista Científica
Publicado em //1986 Português
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The purpose of this paper is to describe the background and methods of a prospective study of medical care utilization and morbidity in a fixed cohort of over 500 preschool children whose families belonged to a prepaid group practice affiliated with Yale University. Following baseline interviews with their mothers, study children were followed for 12 months between 1981 and 1982. Information concerning the subjects' contacts with the health care facility serving members of the group practice was collected from accompanying adults, attending clinicians, and medical records. Using these data, we were able to identify episodes of care, linking all clinical visits and phone calls for single occurrences of an illness or injury. The major aim of the study is to identify psychosocial determinants of pediatric utilization (for both acute and preventive care) and of childhood morbidity. The possible predictors of principal interest are factors associated with the family environment, such as social stress and strain, family structure, and different aspects of the mother's social network. The dual emphasis on both illness and behavior outcomes is based on the important interrelationship between epidemiologic and health services research, especially when examining psychosocial effects.

‣ Complete treatment of uncertainties in a model for dengue R0 estimation

Coelho,Flávio Codeço; Codeço,Cláudia Torres; Struchiner,Claudio José
Fonte: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz Publicador: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2008 Português
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In real epidemic processes, the basic reproduction number R0 is the combined outcome of multiple probabilistic events. Nevertheless, it is frequently modeled as a deterministic function of epidemiological variables. This paper discusses the importance of adequate treatment of uncertainties in such models. This is done by comparing two methods of uncertainty analysis: Monte Carlo uncertainty analysis (MCUA) and the Bayesian melding (BM) method. These methods are applied to a model for the determination of R0 of dengue fever based on entomological parameters. The BM was shown to provide a complete treatment of the uncertainties associated with model parameters. In contrast to MCUA, the incorporation of uncertainties led to realistic posterior distributions for parameter and variables. The incorporation, by the BM, of all the available information, from observational data to expert opinions, allows for the constructive use of uncertainties generating informative posterior distributions for all of the model's components that are coherent as a set.

‣ Casos importados e autóctones na dinâmica da epidemia de dengue no Brasil; Casos importados y autóctonos en la dinámica de epidemias de dengue en Brasil; Imported and autochthonous cases in the dynamics of dengue epidemics in Brazil

Degallier, Nicolas; Favier, Charly; Boulanger, Jean-Philippe; Menkes, Christophe
Fonte: Universidade de São Paulo. Faculdade de Saúde Pública Publicador: Universidade de São Paulo. Faculdade de Saúde Pública
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/02/2009 Português
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OBJETIVO: Estimar o número básico de reprodução da dengue (R0), com base nos casos importados, além dos casos autóctones. MÉTODOS: O estudo foi feito sobre dados epidemiológicos da epidemia de dengue em Brasília, 2003. O número básico de reprodução é determinado a partir da curva epidêmica, ajustando uma reta ao crescimento inicial do número de casos. Para simular uma epidemia com casos autóctones e importados, foi criado um modelo compartimentado do tipo "suscetíveis-infectados-resistentes". O R0 real foi estimado pela fração entre R0 dos casos autóctones e dos importados. RESULTADOS: A comparação de ambos valores de reprodução (apenas autóctones versus todos os casos) mostrou que considerando todos casos como autóctones, o valor de R0 foi superior a um, enquanto o R0 real era inferior a um. O mesmo resultado foi obtido com o conjunto de dados simulando uma epidemia com R0 fixo. O método foi também comparado a outros, observando-se que estes últimos subestimaram os valores do R0. CONCLUSÕES: A inclusão de tanto casos autóctones como os importados é essencial para modelar a dinâmica da epidemia, possibilitando informação crítica aos tomadores de decisão, responsáveis pelo controle da doença.; OBJETIVO: Estimar el número de reproducción básica (R0) de la fiebre del dengue incluyendo casos importados y autóctonos. MÉTODOS: El estudio fue realizado basándose en datos epidemiológicos de la epidemia del dengue ocurrida en Brasilia...

‣ Metodological issues in measuring the detection of emotional disorders by primary care physicians: a review of the literature

Iacoponi,Eduardo
Fonte: Faculdade de Saúde Pública da Universidade de São Paulo Publicador: Faculdade de Saúde Pública da Universidade de São Paulo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/1988 Português
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A series of studies in the field of Epidemiological Psychiatry have been performed over the last two decades, and these have focused on the ability of primary care physicians to detect emotional disorders in the patients that attend their practices. The scientific methodology utilized in these studies is the subject of this review, which contains a discussion concerning: a) interviewer awareness bias; b) accuracy of the instruments and c) medical and psychological concepts involved in defining minor emotional disorders. Suggestions for change in the methodology are made in each of the sections of the review.

‣ Active surveillance for acute flaccid paralysis in poliomyelitis high-risk areas in southern China

Chiba,Yasuo; Hikita,Kazuo; Matuba,Tsuyoshi; Chosa,Tooru; Shinji,Kyogoku; Jingjian,Yu; Zhao,Wang
Fonte: World Health Organization Publicador: World Health Organization
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2001 Português
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OBJECTIVE: On 29 October 2000 poliomyelitis was officially declared to have been eradicated from the Western Pacific Region. This article describes the results of surveillance for cases of acute flaccid paralysis (AFP) in China during the final phase of the eradication effort. METHODS: We conducted hospital-based active surveillance in high-risk areas for poliomyelitis in 5 provinces of southern China (Sichuan, Yunnan, Guizhou, Guangxi and Jiangxi) between 1995 and 1997 to determine the adequacy of reporting and laboratory diagnosis of cases of AFP. FINDINGS: A total of 1069 AFP cases occurring since 1993 were identified in 311 hospital visits. Less than 50% of AFP cases occurring in 1993 and 1994 had been reported by AFP surveillance, and laboratory diagnosis had been carried out on only a small proportion of these. However, improved cooperation between hospital sectors increased the rate of case reporting and laboratory diagnosis to 85% and 78%, respectively, in 1997. Despite this overall improvement, these two indicators were approximately 10-20% lower in Yunnan Province. Epidemiological analysis revealed that cases of clinical poliomyelitis accounted for as much as one-third of all AFP in 1993 and that some of these cases were clustered. Clusters were rarely observed after 1994. Active surveillance in the China-Myanmar border areas of Yunnan over 1995-96 detected 9 cross-border cases of clinical poliomyelitis...

‣ Complete treatment of uncertainties in a model for dengue R0 estimation

Coelho,Flávio Codeço; Codeço,Cláudia Torres; Struchiner,Claudio José
Fonte: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz Publicador: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2008 Português
Relevância na Pesquisa
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In real epidemic processes, the basic reproduction number R0 is the combined outcome of multiple probabilistic events. Nevertheless, it is frequently modeled as a deterministic function of epidemiological variables. This paper discusses the importance of adequate treatment of uncertainties in such models. This is done by comparing two methods of uncertainty analysis: Monte Carlo uncertainty analysis (MCUA) and the Bayesian melding (BM) method. These methods are applied to a model for the determination of R0 of dengue fever based on entomological parameters. The BM was shown to provide a complete treatment of the uncertainties associated with model parameters. In contrast to MCUA, the incorporation of uncertainties led to realistic posterior distributions for parameter and variables. The incorporation, by the BM, of all the available information, from observational data to expert opinions, allows for the constructive use of uncertainties generating informative posterior distributions for all of the model's components that are coherent as a set.

‣ Control of human African trypanosomiasis in the Quiçama focus, Angola

Ruiz,José Antonio; Simarro,Pere P.; Josenando,Teofilo
Fonte: World Health Organization Publicador: World Health Organization
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2002 Português
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OBJECTIVE: To update the epidemiological status of human African trypanosomiasis (HAT), also known as sleeping sickness, in the Quiçama focus, province of Bengo, Angola, and to establish a HAT control programme. METHODS: In 1997, 8796 people (the population of 31 villages) were serologically screened for Trypanosoma brucei gambiense, the causative agent of HAT. In 1998 and 1999, surveys were carried out in villages where HAT cases had been identified in 1997. Individuals were screened using the card agglutination trypanosomiasis test (CATT), and then examined for the presence of the parasite. CATT- positive individuals in whom the presence of the parasite could not be confirmed were further tested with the CATT using serum dilutions, and those with a positive antibody end titre of 1-in-4 or above were followed-up. Patients with £10 white cells/mul and no trypanosomes in their cerebrospinal fluid (CSF) were classified as being in the first stage of the disease. Vector control was not considered necessary or feasible. FINDINGS: The main transmission areas were on the Kwanza riverbanks, where 5042 inhabitants live. In 1997, the HAT prevalence was 1.97%, but this decreased to 0.55% in 1998 and to 0.33% in 1999. The relapse rate was 3% in patients treated with pentamidine and 3.5% in patients treated with melarsoprol. In patients treated with pentamidine...