73 research outputs found

    Characterizing the transitioning epidemiology of herpes simplex virus type 1 in the USA: Model-based predictions

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    Background: Herpes simplex virus type 1 (HSV-1) is a prevalent lifelong infection that appears to be undergoing an epidemiologic transition in the United States (US). Using an analytical approach, this study aimed to characterize HSV-1 transitioning epidemiology and estimate its epidemiologic indicators, past, present, and future. Methods: An age-structured mathematical model was developed to describe HSV-1 transmission through oral and sexual modes of transmission. The model was fitted to the National Health and Nutrition Examination Surveys, 1976-2016 data series. Results: HSV-1 seroprevalence was projected to decline from 61.5% in 1970 to 54.8% in 2018, 48.5% in 2050, and 42.0% in 2100. In 30% for those aged 0-19 years, but 60. Meanwhile, the number of new infections per year (oral and genital) was persistent at 2,762,000 in 1970, 2,941,000 in 2018, 2,933,000 in 2050, and 2,960,000 in 2100. Of this total, genital acquisitions contributed 252,000 infections in 1970, 410,000 in 2018, 478,000 in 2050, and 440,000 in 2100 - a quarter of which are symptomatic with clinical manifestations. For those aged 15-49 years, nearly 25% of incident infections are genital. Most genital acquisitions (> 85%) were due to oral-to-genital transmission through oral sex, as opposed to genital-to-genital transmission through sexual intercourse. Conclusion: HSV-1 epidemiology is undergoing a remarkable transition in the US, with less exposure in childhood and more in adulthood, and less oral but more genital acquisition. HSV-1 will persist as a widely prevalent infection, with ever-increasing genital disease burden.This publication was made possible by NPRP grant number 9-040-3-008 from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors. The authors are also grateful for pilot funding provided by the Biomedical Research Program and infrastructure support provided by the Biostatistics, Epidemiology, and Biomathematics Research Core, both at Weill Cornell Medicine in Qatar

    Herpes simplex virus type 1 epidemiology in Latin America and the Caribbean: Systematic review and meta-analytics

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    Objectives To investigate the epidemiology of herpes simplex virus type 1 (HSV-1) in Latin America and the Caribbean. Methods Systematic review and meta-analytics guided by the Cochrane Collaboration Handbook and reported following the PRISMA guidelines. Results Thirty-three relevant reports were identified including 35 overall (and 95 stratified) seroprevalence measures, and five and nine proportions of virus isolation in genital ulcer disease (GUD) and in genital herpes, respectively. Pooled mean seroprevalence was 57.2% (95% CI: 49.7-64.6%) among children and 88.4% (95% CI: 85.2-91.2%) among adults. Pooled mean seroprevalence was lowest at 49.7% (95% CI: 42.8-56.6%) in those aged ?10, followed by 77.8% (95% CI: 67.9-84.8%) in those aged 10-20, 82.8% (95% CI: 73.1-90.8%) in those aged 20-30, 92.5% (95% CI: 89.4-95.1%) in those aged 30-40, and 94.2% (95% CI: 92.7-95.5%) in those aged ?40. Age was the strongest source of heterogeneity in seroprevalence, explaining 54% of variation. Evidence was found for seroprevalence decline over time. Pooled mean proportion of HSV-1 isolation was 0.9% (95% CI: 0.0-3.6%) in GUD and 10.9% (95% CI: 4.4-19.4%) in genital herpes. Conclusions HSV-1 is a widely prevalent infection in this region, but its epidemiology may be slowly transitioning, with still limited contribution for HSV-1 in genital herpes

    Quasifree kaon-photoproduction from nuclei in a relativistic approach

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    We compute the recoil polarization of the lambda-hyperon and the photon asymmetry for the quasifree photoproduction of kaons in a relativistic impulse-approximation approach. Our motivation for studying polarization observables is threefold. First, polarization observables are more effective discriminators of subtle dynamics than the unpolarized cross section. Second, earlier nonrelativistic calculations suggest an almost complete insensitivity of polarization observables to distortions effects. Finally, this insensitivity entails an enormous simplification in the theoretical treatment. Indeed, by introducing the notion of a ``bound-nucleon propagator'' we exploit Feynman's trace techniques to develop closed-form, analytic expressions for all photoproduction observables. Moreover, our results indicate that polarization observables are also insensitive to relativistic effects and to the nuclear target. Yet, they are sensitive to the model parameters, making them ideal tools for the study of modifications to the elementary amplitude --- such as in the production, propagation, and decay of nucleon resonances --- in the nuclear medium.Comment: 15 pages and 6 figures - submitted to PR

    Association between HCV infection and diabetes type 2 in Egypt: Is it time to split up?

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    Purpose: There is a conflicting evidence about the association between hepatitis C virus (HCV) infection and diabetes mellitus. The objective of this study was to assess this association in Egypt, the country with the highest HCV prevalence in the world. Methods: The source of data was from the Egypt Demographic and Health Survey conducted in 2008. Using multivariable logistic regression analyses to account for known confounders, the association was investigated at two levels']: (1) HCV exposure (HCV antibody status) and diabetes mellitus and (2) diabetes mellitus and chronic HCV infection (HCV RNA status) among HCV-exposed individuals. Results: We found no evidence for an association between HCV antibody status and diabetes (adjusted odds ratio [OR] = 0.87; 95% confidence interval [CI], 0.63-1.19). However, among HCV-exposed individuals, we found an evidence for an association between diabetes and active HCV infection (adjusted OR = 2.44, 95% CI, 1.30-4.57). Conclusions: Although it does not appear that HCV exposure and diabetes are linked, there might be an association between diabetes and chronic HCV infection. The HCV-diabetes relationship may be more complex than previously anticipated. Therefore, a call for an "amicable divorce" to the HCV-diabetes relationship could be premature

    HIV and herpes simplex virus type 2 epidemiological synergy: Misguided observational evidence? A modelling study

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    Objectives To investigate whether observational studies of HIV and herpes simplex virus type 2 (HSV-2) infections have the capacity to assess the HIV/HSV-2 epidemiological synergy. Methods An individual-based Monte Carlo model was used to simulate HIV/HSV-2 epidemics in two scenarios: no HIV/HSV-2 biological interaction and HSV-2 seropositivity enhancing HIV acquisition. Cross-sectional observational studies were simulated by sampling individuals from the population to assess resulting crude and adjusted ORs of the HIV/HSV-2 association. Meta-analyses were conducted to estimate the pooled mean ORs. Impact of under-reporting of sexual behaviour and misc

    Epidemiology of Stroke in the MENA Region: A Systematic Review.

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    Introduction: Stroke is a major burden on the health system due to high fatality and major disability in survivors. Whilst Stroke incidence has declined in the developed world, it continues to increase in developing nations, including the MENA (Middle East and North Africa) region. This may reflect different risk factors and strategies to treat and manage patients prior to and after Stroke. Methods: We have conducted a systematic review of the prevalence, incidence and mortality of Stroke in the 23 countries of MENA region following the PRISMA guidelines. Results: 8,874 published papers were retrieved through both PubMed and Embase. Of those, 38 studies were found to be eligible for inclusion in this review. Only thirteen countries in the MENA region had data points for the critical stroke parameters. Of these qualified studies, 14 were prospective, population-based studies. In the age-adjusted studies, incidence ranged widely between 16/100,000 in a prospective population-based in Iran to 162/100,000 in Libya. Age-adjusted prevalence was available only from Tunisia at 184/100,000. Mortality for all strokes from the eight countries reporting this measure found the 30 day-case fatality ranged from 9.3% in Qatar to 30% in Pakistan. Most stroke studies in the MENA region were small sized, hospital-based, lacked confidence intervals and did not provide prevalence and mortality figures. Conclusion: National policymakers, public health and medical care stakeholders need more reliable epidemiologic studies on Stroke from the MENA region to plan more effective preventive and therapeutic strategies

    Quasifree eta photoproduction from nuclei and medium modifications of resonances

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    We investigate the sensitivity of the differential cross section, recoil nucleon polarization and the photon asymmetry to changes in the elementary amplitude, medium modifications of the resonance (S11,D13)(S_{11},D_{13}) masses, as well as nuclear target effects. All calculations are performed within a relativistic plane wave impulse approximation formalism resulting in analytical expressions for all observables. The spin observables are shown to be unique tools to study subtle effects that are not accessible by only looking at the unpolarized differential cross section.Comment: 27 pages, 8 figures, Revtex, To be published in Phys. Rev.

    Urban Chikungunya in the Middle East and North Africa: A systematic review

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    Background: The epidemiology of Chikungunya virus (CHIKV) in the Middle East and North Africa (MENA) is not well characterized despite increasing recognition of its expanding infection and disease burden in recent years. Methodology / Principal findings: Following Cochrane Collaboration guidelines and reporting our findings following PRISMA guidelines, we systematically reviewed records describing the human prevalence and incidence, CHIKV prevalence/infection rates in vectors, outbreaks, and reported cases for CHIKV across the MENA region. We identified 29 human seroprevalence measures, one human incidence study, one study reporting CHIKV infection rates in Aedes, and nine outbreaks and case reports/series reported in the MENA from 1970–2015. Overall, anti-CHIKV antibody or reports of autochthonous transmission were identified from 10 of 23 countries in the MENA region (Djibouti, Egypt, Iraq, Iran, Kuwait, Pakistan, Saudi Arabia, Somalia, Sudan, and Yemen), with seroprevalence measures among general populations (median 1.0%, range 0–43%) and acute febrile illness populations (median 9.8%, range 0–30%). Sudan reported the highest number of studies (n = 11) and the highest seroprevalence among general populations (median 12%, range 0–43%) and undifferentiated acute febrile illness populations (median 18%, range 10–23%). CHIKV outbreaks were reported from Djibouti, Pakistan, Sudan, and Yemen. Conclusions / Significance: Seroprevalence studies and outbreak reports suggest endemic transmission of urban cycle CHIKV in at least the Red Sea region and Pakistan. However, indications of seroprevalence despite a low quantity of CHIKV epidemiologic research from the region suggests that CHIKV transmission is currently underrecognized

    Global, regional, and national incidence, prevalence, and years lived with disability for 354 Diseases and Injuries for 195 countries and territories, 1990-2017: A systematic analysis for the Global Burden of Disease Study 2017

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    This online publication has been corrected. The corrected version first appeared at thelancet.com on June 20, 2019BACKGROUND:The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. METHODS:We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. FINDINGS:Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). INTERPRETATION:Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury. FUNDING:Bill & Melinda Gates Foundation.Spencer L James ... Azmeraw T Amare ... Peter S Azzopardi ... Bernhard T Baune ... Liliana G Ciobanu ... Garumma Tolu Feyissa ... Tiffany K Gill ... Ratilal Lalloo ... Jean Jacques Noubiap ... Andrew T Olagunju ... Engida Yisma ... et al. (GBD 2017 Disease and Injury Incidence and Prevalence Collaborators

    Abnormal number of Nambu-Goldstone bosons in the color-asymmetric 2SC phase of an NJL-type model

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    We consider an extended Nambu--Jona-Lasinio model including both (q \bar q)- and (qq)-interactions with two light-quark flavors in the presence of a single (quark density) chemical potential. In the color superconducting phase of the quark matter the color SU(3) symmetry is spontaneously broken down to SU(2). If the usual counting of Goldstone bosons would apply, five Nambu-Goldstone (NG) bosons corresponding to the five broken color generators should appear in the mass spectrum. Unlike that expectation, we find only three gapless diquark excitations of quark matter. One of them is an SU(2)-singlet, the remaining two form an SU(2)-(anti)doublet and have a quadratic dispersion law in the small momentum limit. These results are in agreement with the Nielsen-Chadha theorem, according to which NG-bosons in Lorentz-noninvariant systems, having a quadratic dispersion law, must be counted differently. The origin of the abnormal number of NG-bosons is shown to be related to a nonvanishing expectation value of the color charge operator Q_8 reflecting the lack of color neutrality of the ground state. Finally, by requiring color neutrality, two massive diquarks are argued to become massless, resulting in a normal number of five NG-bosons with usual linear dispersion laws.Comment: 13 pages, 4 figures, revtex
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