26 research outputs found

    Serological Evidence of Subclinical Transmission of the 2009 Pandemic H1N1 Influenza Virus Outside of Mexico

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    Background: Relying on surveillance of clinical cases limits the ability to understand the full impact and severity of an epidemic, especially when subclinical cases are more likely to be present in the early stages. Little is known of the infection and transmissibility of the 2009 H1N1 pandemic influenza (pH1N1) virus outside of Mexico prior to clinical cases being reported, and of the knowledge pertaining to immunity and incidence of infection during April-June, which is essential for understanding the nature of viral transmissibility as well as for planning surveillance and intervention of future pandemics. Methodology/Principal Findings: Starting in the fall of 2008, 306 persons from households with schoolchildren in central Taiwan were followed sequentially and serum samples were taken in three sampling periods for haemagglutination inhibition (HI) assay. Age-specific incidence rates were calculated based on seroconversion of antibodies to the pH1N1 virus with an HI titre of 1: 40 or more during two periods: April-June and September-October in 2009. The earliest time period with HI titer greater than 40, as well as a four-fold increase of the neutralization titer, was during April 26-May 3. The incidence rates during the pre-epidemic phase (April-June) and the first wave (July-October) of the pandemic were 14.1% and 29.7%, respectively. The transmissibility of the pH1N1 virus during the early phase of the epidemic, as measured by the effective reproductive number R(0), was 1.16 (95% confidence interval (CI): 0.98-1.34). Conclusions: Approximately one in every ten persons was infected with the 2009 pH1N1 virus during the pre-epidemic phase in April-June. The lack of age-pattern in seropositivity is unexpected, perhaps highlighting the importance of children as asymptomatic transmitters of influenza in households. Although without virological confirmation, our data raise the question of whether there was substantial pH1N1 transmission in Taiwan before June, when clinical cases were first detected by the surveillance network

    DISCOVERING DISASTER EVENTS FROM SOCIAL MEDIA STREAMS

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    Natural and man-made disasters can both cause severe loss of lives and economic damages. Examples include earthquakes, floods, and road crashes. Nevertheless, to rapidly and accurately identify the latest status of a disaster event is undoubtedly one of the most difficult tasks for agencies in crisis management. In this work, we thus propose to monitor online data streams in social media for detecting and tracking real world events. Unlike conventional media, social media is advantageous because of its immediateness, huge data scale, and worldwide availability. Nevertheless, the messages generated by netizens could be incomplete, subjective, or even error prone. Only with an appropriately designated scheme, invaluable clues embedded in huge amounts of online messages can be discovered when carefully exploiting the information over content, temporal, and social dimensions. Specifically, we collect data from multiple social networks, conduct real-time analysis, and present interactive visualization. Experimental studies show that the proposed scheme is demonstrated to be feasible for agencies in practice

    Predicting the progress of colon cancer by DNA methylation markers of the p16 gene in feces - Evidence from an animal model

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    A new noninvasive screening tool for colorectal neoplasia detects epigenetic alterations exhibited by gastrointestinal tumor cells shed into stool. There is insufficient existing data to determine temporal associations between colorectal cancer (CRC) progression and aberrant DNA methylation. To evaluate the feasibility of using fecal DNA methylation status to determine CRC progression, we collected stool samples from 14 male SD rats aged six weeks, and administered subcutaneous injections of either 1,2-dimethylhydrazine or saline weekly. p16 DNA methylation statuses in tumorous and normal colon tissue, and from stool samples were determined using methylation-specific PCR. Additionally, p16 methylation was detected in stool DNA from 85.7% of the CRC rats. The earliest change in p16 methylation status in the DMH-treated group stool samples occurred during week nine; repeatabilities were 57.1% in week 19 (p = 0.070) and 85.7% in week 34 (p = 0.005). A temporal correlation was evidenced between progression of CRC and p16 methylation status, as evidenced by DMH-induced rat feces. Using fecal DNA methylation status to determine colorectal tissue methylation status can reveal CRC progression. Our data suggests that p16 promoter methylation is a feasible epigenetic marker for the detection and may be useful for CRC screening

    Hepatitis C Virus Infection among Injection Drug Users with and without Human Immunodeficiency Virus Co-Infection

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    <div><p>The aim of this study is to explore the prevalence of hepatitis C virus (HCV) infection among injection drug users (IDUs) with and without human immunodeficiency virus (HIV) infection in southern Taiwan. For 562 IDUs (265 anti-HIV negative, 297 anti-HIV positive), we analyzed liver function, anti-HIV antibody, anti-HCV antibody, HCV viral loads, and hepatitis B surface antigen (HBsAg). HIV RNA viral loads and CD4 cell count for anti-HIV-seropositive IDUs and the HCV genotype for HCV RNA-seropositive IDUs were measured. The seroprevalence rates of anti-HIV, anti-HCV, and HBsAg were 52.8%, 91.3%, and 15.3%, respectively. All the anti-HIV-seropositive IDUs were positive for HIV RNA. Anti-HCV seropositivity was the most important factor associated with HIV infection (odds ratio [OR], 25.06; 95% confidence intervals [CI], 8.97–74.9), followed by male gender (OR, 6.12; 95% CI, 4.05–9.39) and HBsAg seropositivity (OR, 1.90; 95% CI, 1.11–3.34). Among IDUs positive for anti-HCV, 80.7% had detectable HCV RNA. HCV viremia after HCV exposure was strongly related to HIV infection (OR, 6.262; 95% CI, 1.515–18.28), but negatively correlated to HBsAg seropositivity (OR, 0.161; 95% CI, 0.082–0.317). HCV genotype 6 was the most prevalent genotype among all IDUs (41.0%), followed by genotypes 1 (32.3%), 3 (12.8%), and 2 (5.6%). In conclusion, about half IDUs were infected with HIV and >90% with HCV infection. Male and seropositivity for HBsAg and anti-HCV were factors related to HIV infection among our IDUs. HIV was positively correlated, whereas hepatitis B co-infection was negatively correlated with HCV viremia among IDUs with HCV exposure. Different HCV molecular epidemiology was noted among IDUs.</p></div

    Serological response and persistence in schoolchildren with high baseline seropositive rate after receiving 2009 pandemic influenza A(H1N1) vaccine

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    The serological response of the current 2009 H1N1 pandemic influenza monovalent vaccine in children exhibiting high baseline seropositive rate was evaluated though a community-based household study. Seroprotection rate of >90% and seroconversion rate of >50% were observed in children one month after receiving the pandemic vaccine. Among children with low baseline antibody titer, a significant lower seroconversion rate (55%) was observed in children who received seasonal trivalent inactivated vaccine (TIV) prior to pandemic vaccine, when compared with those receiving the pandemic vaccine only (86%). Persistence of antibody against the pandemic influenza virus was observed 6 months after vaccination in >80% of children presenting seroprotective antibody levels. (C) 2010 Elsevier Ltd. All rights reserved

    Multivariate analysis of factors associated with HIV infection status among IDUs.

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    <p>HIV, human immunodeficiency virus; HBsAg, hepatitis B surface antigen; HCV, hepatitis C virus.</p><p>Factors used for logistic analysis included gender, age, hepatitis B surface antigen (HBsAg) status and anti-HCV antibody status.</p

    Characteristics and virological features of 562 IDUs with and without HIV infection.

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    <p>IDU, injection drug users; SD, standard deviation; AST, aspartate aminotransferase; ALT, alanine aminotransferase; HBsAg, hepatitis B surface antigen; HCV, hepatitis C virus</p>a<p>Ratio relative to upper normal limit, the unit of AST and ALT is IU/L.</p>b<p>Mann–Whitney <i>U</i>-test.</p>c<p>For 173 HCV RNA detectable IDUs without HIV infection and 241 HCV RNA undetectable IDUs with HIV infection.</p>d<p>All anti-HIV-positive subjects were seropositive for HIV RNA.</p
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