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1.
Acta Derm Venereol ; 104: adv32323, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38738773

RESUMEN

Recap of atopic eczema (RECAP) is a self-reported 7-item questionnaire recommended by the Harmonising Outcome Measures in Eczema initiative to measure eczema control. As RECAP has not been validated in a real-world clinical population in Asia, RECAP was investigated as a measure of eczema control in Singapore. Patients with atopic eczema at the National Skin Centre from July 2019 to January 2020 were included for analysis. Both patient- and physician-reported outcome measures were available for correlation analyses. Correlation analysis was also performed to investigate construct validity, and floor or ceiling effects of RECAP. A total of 260 atopic eczema patients aged between 15 and 87 years were recruited. There were minimal floor and ceiling effects for RECAP scores. There were strong, significant correlations of RECAP with POEM (r = 0.84, p < 0.001) and DLQI (r = 0.81, p < 0.001). Correlation with SCORAD was moderate (r = 0.60, p < 0.001). Correlations remained similar after age, gender, and ethnicity adjustments. Discriminative validity was demonstrated by a significant linear trend of increasing RECAP scores with increasing eczema severity. RECAP demonstrates good discriminative and construct validity evidenced by strong correlations with symptoms and quality of life and moderate correlations with eczema signs. RECAP is useful to measure eczema control in Singapore.


Asunto(s)
Dermatitis Atópica , Calidad de Vida , Índice de Severidad de la Enfermedad , Humanos , Adulto , Femenino , Masculino , Persona de Mediana Edad , Singapur/epidemiología , Dermatitis Atópica/diagnóstico , Anciano , Adolescente , Adulto Joven , Anciano de 80 o más Años , Reproducibilidad de los Resultados , Medición de Resultados Informados por el Paciente , Valor Predictivo de las Pruebas , Autoinforme
2.
Exp Dermatol ; 32(11): 2023-2028, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37583346

RESUMEN

Interim analysis of the National Skin Centre Singapore Psoriasis Biologics Registry (SINGPSOR) from August 2017 to May 2021, in which 58 patients were analysed, showing that those receiving biologic treatment had significantly more severe psoriasis based on PASI (Psoriasis Area and Severity Index), BSA (body surface area) and PGA (Physician Global Assessment) measures at baseline, demonstrated a statistically non-significant trend towards greater improvement with treatment, and had a lower percentage of adverse events compared to those receiving conventional systemic therapy. Future analyses of SINGPSOR, with larger sample size and longer follow-up, will be invaluable to further characterize these patients and their treatment outcomes.


Asunto(s)
Productos Biológicos , Psoriasis , Humanos , Singapur , Psoriasis/tratamiento farmacológico , Psoriasis/inducido químicamente , Resultado del Tratamiento , Sistema de Registros , Productos Biológicos/uso terapéutico , Medición de Resultados Informados por el Paciente , Índice de Severidad de la Enfermedad , Adalimumab/uso terapéutico
3.
Photodermatol Photoimmunol Photomed ; 39(4): 343-350, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36345565

RESUMEN

BACKGROUND: Previous studies regarding the risk of skin malignancy with NBUVB have been performed in Caucasian patients, but few studies have been conducted in Asians. AIM: The aim of the study was to determine the risk of skin cancer in Asian patients with psoriasis and vitiligo receiving NBUVB phototherapy. METHODS: We performed a 9-year retrospective study including all patients with psoriasis and vitiligo receiving NBUVB (either 311 nm wavelength through cabin phototherapy or 308 nm through excimer lamp phototherapy) at the National Skin Centre. We matched the identification numbers of patients to the National Registry of Diseases Office database and collected data on all skin cancers diagnosed. RESULTS: A total of 3730 patients were included. During the course of the study, 12 cases of skin cancer were diagnosed, of which 10 were basal cell carcinomas, and 2 were squamous cell carcinomas. No cases of melanoma were detected in the study. The age-standardized incidence of skin cancer in psoriasis and vitiligo patients who received phototherapy was 47.5 and 26.5, respectively, which is higher than the incidence of skin cancers in the general population. Risk of skin malignancy was positively correlated with the cumulative (p = .008) and maximum dose of phototherapy (p = .011) as well as previous systemic treatments (p = .006). LIMITATIONS: Limitations include a relatively short follow-up period as well as the lack of quantification of solar exposure. CONCLUSIONS: NBUVB phototherapy in Asian skin increases the risk of skin malignancy. The risk of skin malignancy is higher with psoriasis patients, greater cumulative and maximal dose of phototherapy as well as the use of systemic therapy. Despite the increased risk, the absolute number of skin malignancies remains low, especially for vitiligo patients, with no cases of melanoma diagnosed-a reassuring finding that phototherapy remains a safe alternative in the treatment of psoriasis and vitiligo.


Asunto(s)
Melanoma , Psoriasis , Neoplasias Cutáneas , Terapia Ultravioleta , Vitíligo , Humanos , Estudios Retrospectivos , Vitíligo/epidemiología , Incidencia , Terapia Ultravioleta/efectos adversos , Fototerapia/efectos adversos , Psoriasis/complicaciones , Psoriasis/epidemiología , Psoriasis/radioterapia , Neoplasias Cutáneas/epidemiología , Neoplasias Cutáneas/etiología , Melanoma/epidemiología , Melanoma/radioterapia , Resultado del Tratamiento
4.
Australas J Dermatol ; 64(3): 368-377, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37162207

RESUMEN

BACKGROUND: Atopic dermatitis (AD) is one of the most prevalent chronic inflammatory skin conditions. We aimed to describe the clinical features of adult-onset and childhood-onset AD in a multi-ethnic Asian population. METHODS: A retrospective study was performed of 188 patients with AD managed at a tertiary skin institution in Singapore. Patient demographics, clinical features and disease scores were analysed. RESULTS: Clinical features related to pigmentary changes, such as orbital darkening and Dennie-Morgan folds were more prevalent among childhood-onset AD patients than in adult-onset AD patients. Similarly, features related to prolonged scratching or friction, such as anterior neck folds, perifollicular accentuation and infra-auricular/infranasal fissuring were also more prevalent in childhood-onset AD patients. Disease scores such as SCORAD and EASI were not different between patients with childhood versus adult-onset disease. CONCLUSION: There were significant differences in clinical features between childhood-onset and adult-onset AD. Certain features are related to pigmentary changes and might be more accentuated in patients with skin of colour. Further studies are needed to understand how the different features might be clinically significant and related to the various AD endotypes and disease trajectories.


Asunto(s)
Dermatitis Atópica , Humanos , Adulto , Dermatitis Atópica/diagnóstico , Dermatitis Atópica/epidemiología , Estudios Retrospectivos , Piel , Singapur/epidemiología , Índice de Severidad de la Enfermedad
5.
Contact Dermatitis ; 86(5): 398-403, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35133669

RESUMEN

BACKGROUND: Although the traditional understanding is that contact sensitization is less frequent in patients with atopic dermatitis (AD), recent studies have shown similar or higher rates of positive patch-test results in AD patients. OBJECTIVES: We sought to characterise the pattern of contact sensitization in patients with and without AD and evaluate the association between AD and contact sensitization. METHOD: This was a single-center, 10-year retrospective review of patients who underwent patch testing between 2007 and 2017. RESULTS: There were 4903 patients (male-to-female ratio = 1:1.4; mean age 40.1 years) included. About half (2499, 51.0%) of all patients developed at least one positive reaction. The top five frequent reactions were to nickel sulfate (45.4%), potassium dichromate (16.0%), p-phenylenediamine (13.4%), Myroxylon pereirae (11.8%), and fragrance mix I (11.2%). The overall prevalence of contact sensitization was not significantly different between patients with or without AD. Patients with AD were less likely to develop contact allergies to budesonide and thiuram mix, and more likely to develop contact allergies to potassium dichromate. CONCLUSIONS: Contact sensitization was detected in 50% of patients who were patch tested. Nickel sulfate was the most frequently sensitizing allergen. The prevalence of contact allergies in atopic patients is comparable to that in non-atopic patients.


Asunto(s)
Dermatitis Alérgica por Contacto , Dermatitis Atópica , Dermatología , Adulto , Alérgenos/efectos adversos , Dermatitis Alérgica por Contacto/epidemiología , Dermatitis Alérgica por Contacto/etiología , Dermatitis Atópica/inducido químicamente , Dermatitis Atópica/epidemiología , Femenino , Humanos , Masculino , Pruebas del Parche/métodos , Dicromato de Potasio/efectos adversos , Estudios Retrospectivos
6.
Pediatr Dermatol ; 39(1): 69-76, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34971009

RESUMEN

BACKGROUND: Pediatric allergic contact dermatitis (ACD) is increasingly prevalent. Patch testing is the gold-standard diagnostic investigation. The aims of our study were to describe the clinical profile of pediatric patients with ACD in a multi-ethnic Asian population and identify the common contact allergens. METHODS: This was a retrospective study involving children and adolescents aged 16 years or younger with clinically suspected ACD who underwent patch testing between January 2007 and March 2020 at two institutions in Singapore. Information pertaining to their demographics, atopy history, clinical presentation, and patch test results was analyzed. RESULTS: A total of 252 patients were included. The mean age was 10.9 years (1.0-16.7 years). The majority were Chinese (79.8%) and girls (57.5%). Many (66.3%) had atopic dermatitis (AD), which was mild. The most common presentation was an acral eczematous rash. The sensitization rate was 50.0%. The most frequent reactions were to nickel sulfate (49.2%) and fragrance mix (19.1%). The overall rate of relevant positive patch tests was 72.5%. Patients with AD were less likely to have a reaction to fragrance mix (p = .019) and more likely to have a reaction to disperse blue (p = .041). Compared to younger children, adolescents were less likely to have a positive patch test (p = .008). Indians were also less likely to have a positive reaction (p = .004). CONCLUSION: Metals and fragrances were the most common allergens causing childhood ACD in Singapore. Patients with AD were less likely to be sensitized to fragrances and more likely to be sensitized to disperse blue dye.


Asunto(s)
Dermatitis Alérgica por Contacto , Dermatitis Atópica , Adolescente , Alérgenos , Niño , Preescolar , Dermatitis Alérgica por Contacto/diagnóstico , Dermatitis Alérgica por Contacto/epidemiología , Femenino , Humanos , Lactante , Masculino , Pruebas del Parche , Estudios Retrospectivos
7.
Neurochem Res ; 46(7): 1801-1813, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33871800

RESUMEN

This study was designed to investigate the role of miR-671-5p in in vitro and in vivo models of ischemic stroke (IS). Middle cerebral artery occlusion and reperfusion (MCAO/R) in C57BL/6 mice as well as oxygen-glucose deprivation and reoxygenation (OGD/R) in a mouse hippocampal HT22 neuron line were used as in vivo and in vitro models of IS injury, respectively. miR-671-5p agomir, miR-671-5p antagomir, pcDNA3.1-NF-κB, and negative controls were transfected into cells using riboFECT CP reagent. miR-671-5p agomir, pcDNA3.1-NF-κB, and negative vectors were administered into MCAO/R mice via intracerebroventricular injection. The results showed that miR-671-5p was significantly downregulated and that miR-671-5p agomir alleviated injury and neuroinflammation induced by ischemic reperfusion. A dual-luciferase reporter assay confirmed that NF-κB is a direct target of miR-671-5p. Reverse experiments showed that miR-671-5p agomir reduced neuroinflammation via suppression of NF-κB expression in both in vitro and in vivo models of IS. Our data suggest that miR-671-5p may be a viable therapeutic target for diminishing neuroinflammation in patients with IS.


Asunto(s)
Infarto de la Arteria Cerebral Media/metabolismo , Inflamación/metabolismo , MicroARNs/metabolismo , Subunidad p50 de NF-kappa B/metabolismo , Animales , Antagomirs/farmacología , Encéfalo/patología , Hipoxia de la Célula/fisiología , Línea Celular , Regulación hacia Abajo/fisiología , Glucosa/deficiencia , Infarto de la Arteria Cerebral Media/complicaciones , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Infarto de la Arteria Cerebral Media/patología , Inflamación/tratamiento farmacológico , Inflamación/etiología , Inflamación/patología , Masculino , Ratones Endogámicos C57BL , MicroARNs/agonistas , MicroARNs/antagonistas & inhibidores , Oxígeno/metabolismo
8.
J Gastroenterol Hepatol ; 36(6): 1529-1537, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33047825

RESUMEN

BACKGROUND AND AIM: The impact of chronic constipation on health-related quality of life (HRQoL), work productivity, and healthcare resource use in Japan is not well understood. This study aimed to evaluate and compare the humanistic burden of respondents with chronic constipation to respondents without chronic constipation and to respondents with type 2 diabetes mellitus (T2DM), irritable bowel syndrome (IBS), and gastroesophageal reflux disease (GERD), respectively. METHODS: This cross-sectional study collected demographic and general health data and HRQoL data as measured by the Short Form 12-Item (Version 2) Health Survey and EuroQol 5-dimension health surveys. Health impacts on employment-related activities and indirect costs were measured using the Work Productivity and Activity Impairment questionnaire. Propensity score matching was used to identify a control group without chronic constipation. Multivariate generalized linear models were used to identify potential factors that may impact the outcomes of respondents. RESULTS: A total of 30 001 individuals responded to the Japan National Health and Wellness Survey 2017, whereof 3373 (11.2%) reported having chronic constipation; 963 were physician diagnosed. Compared with matched controls, patients with physician-diagnosed chronic constipation had lower mean HRQoL scores and higher mean absenteeism, presenteeism, total Work Productivity and Activity Impairment, and indirect costs. Physician-diagnosed chronic constipation was associated with a higher health burden than T2DM, IBS, and GERD. CONCLUSIONS: Chronic constipation is associated with a considerable health burden, which is higher compared with T2DM, IBS, and GERD. These results suggest an urgent need for effective treatment of Japanese patients with chronic constipation to improve their quality of life.


Asunto(s)
Estreñimiento/fisiopatología , Estreñimiento/psicología , Eficiencia/fisiología , Medicina del Trabajo , Calidad de Vida , Rendimiento Laboral/estadística & datos numéricos , Adulto , Anciano , Pueblo Asiatico , Enfermedad Crónica , Estreñimiento/terapia , Costo de Enfermedad , Estudios Transversales , Diabetes Mellitus Tipo 2 , Femenino , Reflujo Gastroesofágico , Humanos , Síndrome del Colon Irritable , Japón , Masculino , Persona de Mediana Edad
9.
Appetite ; 148: 104555, 2020 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-31843684

RESUMEN

BACKGROUND: Many countries recommend parental involvement to enhance the effectiveness of healthy lifestyle interventions focusing on behavioural modifications that encourage weight management in children. Our study investigates to what extent the different constructs of the Theory of Planned Behaviour (TPB) are influencing healthy eating behaviour among mothers of pre-school and primary school children in Singapore. METHODS: A total of 716 mothers of pre-schoolers, 3-6 years old (N = 358) and primary school students, 7-12 years old (N = 358) were administered a survey to assess healthy eating behaviour using the TPB constructs. Bivariate correlations among TPB constructs were calculated and tested using Pearson's correlation. Multivariate generalized regression was performed to examine the associations between TPB constructs and healthy eating behaviour. RESULTS: More than 80% of children consumed less than the daily recommended servings of at least 1 glass of dairy,2 servings of fruit and 2 servings of vegetables per day advised by the Singapore Health Board. More primary school children consumed less dairy per day compared to pre-school children (48.9% vs 26.3%; p < 0.001). Primary school children's healthy eating behaviours were correlated with mother's perceived behavioural control (PBC) such as adequate discipline (ß = 0.40; p = 0.001), self-efficacy (ß = 0.35; p = 0.01) and a lower barrier that healthy food does not satisfy hunger (ß = -1.16; p < 0.001). Barriers that significantly reduced pre-school children's healthy food intake were lack of motivation among mothers (ß = -1.13; p < 0.001) and children (ß = -0.49; p = 0.02), lack of satiety (ß = -1.06; p = 0.02), difficulty in changing child's eating habits (ß = -0.58; p = 0.03), lack of family support (ß = -0.62; p = 0.03). CONCLUSIONS: Findings from this study provides a formative foundation for future research and exploration of plausible interventions around improving mother's PBC, self-efficacy and reducing barriers, which could increase mother's engagement in improving their children's healthy eating behaviours in Singapore.


Asunto(s)
Conducta Infantil , Dieta Saludable , Conducta Alimentaria , Conocimientos, Actitudes y Práctica en Salud , Relaciones Madre-Hijo , Madres , Adulto , Niño , Preescolar , Estudios Transversales , Cultura , Dieta , Familia , Femenino , Humanos , Hambre , Masculino , Persona de Mediana Edad , Madres/psicología , Motivación , Saciedad , Autoeficacia , Singapur , Encuestas y Cuestionarios
10.
J Infect Dis ; 219(12): 1913-1923, 2019 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-30722024

RESUMEN

BACKGROUND: Few studies have evaluated the relative cross-protection conferred by infection with different groups of viruses through studies of sequential infections in humans. We investigated the presence of short-lived relative cross-protection conferred by specific prior viral infections against subsequent febrile respiratory illness (FRI). METHODS: Men enlisted in basic military training between December 2009 and December 2014 were recruited, with the first FRI as the study entry point. ResPlex II assays and real-time polymerase chain reaction assays were used to detect viral pathogens in nasal wash samples, and survival analyses were performed to determine whether infection with particular viruses conferred short-lived relative cross-protection against FRI. RESULTS: Prior infection with adenovirus (hazard ratio [HR], 0.24; 95% confidence interval [CI], .14-.44) or influenza virus (HR, 0.52; 95% CI, .38-.73) conferred relative protection against subsequent FRI episode. Results were statistically significant even after adjustment for the interval between enlistment and FRI (P < .001). Adenovirus-positive participants with FRI episodes tended to be protected against subsequent infection with adenovirus, coronavirus, enterovirus/rhinovirus, and influenza virus (P = .062-.093), while men with influenza virus-positive FRI episodes tended be protected against subsequent infection with adenovirus (P = .044) and influenza virus (P = .081). CONCLUSION: Prior adenovirus or influenza virus infection conferred cross-protection against subsequent FRI episodes relative to prior infection due to other circulating viruses.


Asunto(s)
Protección Cruzada/inmunología , Infecciones del Sistema Respiratorio/inmunología , Virosis/inmunología , Virus/inmunología , Femenino , Humanos , Masculino , Personal Militar , Infecciones del Sistema Respiratorio/virología , Singapur , Análisis de Supervivencia , Virosis/virología
11.
J Bone Miner Metab ; 37(2): 307-318, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29520508

RESUMEN

Osteoporosis remains undertreated in Japan, and bone fractures are the most frequent complications imposing heavy burden on individuals and the community. This paper investigates the clinical and economic burden of fractures among osteoporosis patients in Japan. The Japan National Health and Wellness Survey 2012-2014 database was used for analysis. Respondents aged ≥ 50 years and indicated a physician diagnosis of osteoporosis (N = 1107) were categorized into three subgroups: no prior fracture (N = 693), single fracture (N = 242), and multiple (≥ 2) fractures (N = 172). Health-related quality of life (HRQoL), work productivity and activity impairment, healthcare resource utilization and associated direct and indirect costs were compared across three fracture subgroups adjusting for respondents' sociodemographic and clinical characteristics using generalized linear regression models. The estimated fracture prevalence among respondents with osteoporosis who were ≥ 50 years was 37.4%, of whom 41.5% had multiple fractures. Relative to osteoporosis respondents with no fracture and with single fracture, those with multiple fractures reported significant higher disability in HRQoL, more healthcare resource utilization, and were associated with higher direct costs. Improved treatment of fractures among osteoporosis patients is necessary and may help reduce the clinical and economic burden in this osteoporosis population.


Asunto(s)
Costo de Enfermedad , Eficiencia , Ejercicio Físico , Recursos en Salud/economía , Osteoporosis/economía , Calidad de Vida , Absentismo , Anciano , Servicio de Urgencia en Hospital , Femenino , Encuestas Epidemiológicas , Humanos , Japón/epidemiología , Masculino , Osteoporosis/diagnóstico , Osteoporosis/epidemiología , Fracturas Osteoporóticas/economía , Prevalencia , Autoinforme
12.
Am J Epidemiol ; 187(1): 135-143, 2018 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-29309522

RESUMEN

Seasonal influenza epidemics occur year-round in the tropics, complicating the planning of vaccination programs. We built an individual-level longitudinal model of baseline antibody levels, time of infection, and the subsequent rise and decay of antibodies postinfection using influenza A(H1N1)pdm09 data from 2 sources in Singapore: 1) a noncommunity cohort with real-time polymerase chain reaction-confirmed infections and at least 1 serological sample collected from each participant between May and October 2009 (n = 118) and 2) a community cohort with up to 6 serological samples collected between May 2009 and October 2010 (n = 760). The model was hierarchical, to account for interval censoring and interindividual variation. Model parameters were estimated via a reversible jump Markov chain Monte Carlo algorithm using custom-designed R (https://www.r-project.org/) and C++ (https://isocpp.org/) code. After infection, antibody levels peaked at 4-7 weeks, with a half-life of 26.5 weeks, followed by a slower decrease up to 1 year to approximately preinfection levels. After the third wave, the seropositivity rate and the population-level antibody titer dropped to the same level as they were at the end of the first pandemic wave. The results of this analysis are consistent with the hypothesis that the population-level effect of individuals' waxing and waning antibodies influences influenza seasonality in the tropics.


Asunto(s)
Anticuerpos Antivirales/sangre , Subtipo H1N1 del Virus de la Influenza A/inmunología , Gripe Humana/epidemiología , Estaciones del Año , Clima Tropical , Femenino , Humanos , Gripe Humana/inmunología , Estudios Longitudinales , Masculino , Método de Montecarlo , Estudios Seroepidemiológicos , Singapur/epidemiología
14.
Epidemiology ; 27(1): 143-51, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26427723

RESUMEN

BACKGROUND: Correlations between hemagglutination-inhibition titers (hereafter "titers") and protection against infection have been identified in historical studies. However, limited information is available about the dynamics of how titer influences protection. METHODS: Titers were measured in randomized, placebo-controlled vaccine trials in Hong Kong among pediatrics during September 2009-December 2010 and the United States among adults during Oct 2007-April 2008. Intermediate unobserved titers were imputed using three interpolation methods. As participants were recruited at different times leading to varying exposure to infection relative to entry, a modified proportional hazards model was developed to account for staggered entry into the studies and to quantify the correlation of titers with protection against influenza infections, adjusting for waning in titers. The model was fitted using Markov chain Monte Carlo and importance sampling. RESULTS: A titer of 1:40 was associated with a reduced infection risk of 40%-70% relative to a titer of 1:10, depending on the circulating strain; the corresponding protection associated with a titer of 1:80 was 54%-84%. Results were robust across interpolation methods. The trivalent-inactivated vaccine reduced cumulative incidence of influenza B and influenza A(H3N2) infections by six percentage points (pp; 95% credible interval = 2 pp, 10 pp) and 1 pp (95% credible interval = 0.3 pp, 2 pp) respectively, but not for influenza A(H1N1)pdm09. The live-attenuated vaccine showed little efficacy against influenza A(H3N2) infections. CONCLUSIONS: Titers are correlated with protection against influenza infections. The trivalent inactivated vaccine can reduce the risk of influenza A(H3N2) and influenza B infections in the community.


Asunto(s)
Subtipo H1N1 del Virus de la Influenza A/inmunología , Subtipo H3N2 del Virus de la Influenza A/inmunología , Virus de la Influenza B/inmunología , Vacunas contra la Influenza/inmunología , Gripe Humana/prevención & control , Adolescente , Adulto , Niño , Femenino , Pruebas de Inhibición de Hemaglutinación , Hong Kong/epidemiología , Humanos , Incidencia , Gripe Humana/epidemiología , Gripe Humana/inmunología , Masculino , Persona de Mediana Edad , Estados Unidos/epidemiología , Adulto Joven
18.
BMC Infect Dis ; 14: 539, 2014 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-25280926

RESUMEN

BACKGROUND: The distributions of incubation and relapse periods are key components of infectious disease models for the malaria parasite Plasmodium vivax; however, detailed distributions based upon experimental data are lacking. METHODS: Using a range of historical, experimental mosquito-transmitted human infections, Bayesian estimation with non-informative priors was used to determine parametric distributions that can be readily implemented for the incubation period and time-to-first relapse in P. vivax infections, including global subregions by parasite source. These analyses were complemented with a pooled analysis of observational human infection data with infections that included malaria chemoprophylaxis and long-latencies. The epidemiological impact of these distributional assumptions was explored using stochastic epidemic simulations at a fixed reproductive number while varying the underlying distribution of incubation periods. RESULTS: Using the Deviance Information Criteria to compare parameterizations, experimental incubation periods are most closely modeled with a shifted log-logistic distribution; a log-logistic mixture is the best fit for incubations in observational studies. The mixture Gompertz distribution was the best fit for experimental times-to-relapse among the tested parameterizations, with some variation by geographic subregions. Simulations suggest underlying distributional assumptions have critically important impacts on both the time-scale and total case counts within epidemics. CONCLUSIONS: These results suggest that the exponential and gamma distributions commonly used for modeling incubation periods and relapse times inadequately capture the complexity in the distributions of event times in P. vivax malaria infections. In future models, log-logistic and Gompertz distributions should be utilized for general incubation periods and relapse times respectively, and region-specific distributions should be considered to accurately model and predict the epidemiology of this important human pathogen.


Asunto(s)
Malaria Vivax/parasitología , Plasmodium vivax/fisiología , Teorema de Bayes , Quimioprevención , Epidemias , Humanos , Malaria Vivax/patología , Recurrencia , Factores de Tiempo
19.
BMC Infect Dis ; 14: 204, 2014 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-24735158

RESUMEN

BACKGROUND: Few studies have comprehensively described tropical respiratory disease surveillance in military populations. There is also a lack of studies comparing clinical characteristics of the non-influenza pathogens with influenza and amongst themselves. METHODS: From May 2009 through October 2012, 7733 consenting cases of febrile respiratory illness (FRI) (temperature [greater than or equal to]37.5 degrees C with cough or sorethroat) and controls in the Singapore military had clinical data and nasal washes collected prospectively. Nasal washes underwent multiplex PCR, and the analysis was limited to viral mono-infections. RESULTS: 49% of cases tested positive for at least one virus, of whom 10% had multiple infections. 53% of the FRI cases fulfilled the definition of influenza-like illness (ILI), of whom 52% were positive for at least one virus. The most frequent etiologies for mono-infections among FRI cases were Influenza A(H1N1)pdm09 (13%), Influenza B (13%) and coxsackevirus (9%). The sensitivity, specificity, positive predictive value and negative predictive value of ILI for influenza among FRI cases were 72%, 48%, 40% and 69% respectively. On logistic regression, there were marked differences in the prevalence of different symptoms and signs between viruses with fever more prevalent amongst influenza and adenovirus infections than other viruses. CONCLUSION: There are multiple viral etiologies for FRI and ILI with differing clinical symptoms in the Singapore military. Influenza and coxsackevirus were the most common etiology for FRI, while influenza and adenoviruses displayed the most febrile symptoms. Further studies should explore these differences and possible interventions.


Asunto(s)
Personal Militar , Virosis/epidemiología , Adulto , Femenino , Humanos , Vacunas contra la Influenza , Gripe Humana/diagnóstico , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Gripe Humana/virología , Modelos Logísticos , Masculino , Prevalencia , Sensibilidad y Especificidad , Vigilancia de Guardia , Singapur/epidemiología , Virosis/diagnóstico , Virosis/virología
20.
BMC Infect Dis ; 14: 414, 2014 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-25066592

RESUMEN

BACKGROUND: The rate of decline of antibody titers to influenza following infection can affect results of serological surveys, and may explain re-infection and recurrent epidemics by the same strain. METHODS: We followed up a cohort who seroconverted on hemagglutination inhibition (HI) antibody titers (≥ 4-fold increase) to pandemic influenza A(H1N1)pdm09 during a seroincidence study in 2009. Along with the pre-epidemic sample, and the sample from 2009 with the highest HI titer between August and October 2009 (A), two additional blood samples obtained in April 2010 and September 2010 (B and C) were assayed for antibodies to A(H1N1)pdm09 by both HI and virus microneutralization (MN) assays. We analyzed pair-wise mean-fold change in titers and the proportion with HI titers ≥ 40 and MN ≥ 160 (which correlated with a HI titer of 40 in our assays) at the 3 time-points following seroconversion. RESULTS: A total of 67 participants contributed 3 samples each. From the highest HI titer in 2009 to the last sample in 2010, 2 participants showed increase in titers (by HI and MN), while 63 (94%) and 49 (73%) had reduction in HI and MN titers, respectively. Titers by both assays decreased significantly; while 70.8% and 72.3% of subjects had titers of ≥ 40 and 160 by HI and MN in 2009, these percentages decreased to 13.9% and 36.9% by September 2010. In 6 participants aged 55 years and older, the decrease was significantly greater than in those aged below 55, so that none of the elderly had HI titers ≥ 40 nor MN titers ≥ 160 by the final sample. Due to this decline in titers, only 23 (35%) of the 65 participants who seroconverted on HI in sample A were found to seroconvert between the pre-epidemic sample and sample C, compared to 53 (90%) of the 59 who seroconverted on MN on Sample A. CONCLUSIONS: We observed marked reduction in titers 1 year after seroconversion by HI, and to a lesser extent by MN. Our findings have implications for re-infections, recurrent epidemics, vaccination strategies, and for cohort studies measuring infection rates by seroconversion.


Asunto(s)
Anticuerpos Antivirales/inmunología , Subtipo H1N1 del Virus de la Influenza A/inmunología , Gripe Humana/inmunología , Adulto , Anciano , Estudios de Cohortes , Femenino , Pruebas de Inhibición de Hemaglutinación , Humanos , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Humana/epidemiología , Gripe Humana/virología , Masculino , Persona de Mediana Edad , Pruebas de Neutralización , Singapur/epidemiología , Vacunación/métodos , Adulto Joven
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