11 May 2015

Research Committee Articles of the Week, May 11, 2015

Articles from May_11_2015

Research Committee Selected Articles for the Week of May_11_2015

Communicating on Twitter during a disaster: An analysis of tweets during Typhoon Haiyan in the Philippines

Social media in crisis situations, such as natural disasters, have been recognized by scholars and practitioners as key communication channels that can complement traditional channels. However, there is limited empirical examination from the user perspective of the functions that social media play and the factors that explain such uses. In this study we examine Twitter use during and after Typhoon Haiyan pummeled the Philippines. We tested a typology of Twitter use based on previous research, and explored external factors - time of use and geographic location - and internal factors - type of stakeholders (e.g. ordinary citizens, journalists, etc.) and social media engagement - to predict these uses. The results showed that different stakeholders used social media mostly for dissemination of second-hand information, in coordinating relief efforts, and in memorializing those affected. Recommendations for future research and applications in future crises are also presented. © 2015 Elsevier Ltd.

An educational programme for nursing college staff and students during a MERS- coronavirus outbreak in Saudi Arabia

Background: The Middle Eastern Respiratory Syndrome Coronavirus is a serious and emerging issue in Saudi Arabia and the world. A response was required to reduce possible disease transmission between the hospital and university. College of Nursing academic staff developed a programme in response to the educational and emotional needs of participants. Methods: A MERS-CoV Task Force responded to the rapidly unfolding epidemic. The aim was to find out what nursing staff and nursing students in the college knew about MERS- CoV. While most gaps in knowledge were addressed after an intense information seminar, other learning needs were identified and responded to. Results: The total number of people attending the education sessions was133, including 65 students. 18 faculty members attended and 57 support staff. Data was gathered on gaps in participant knowledge and a plan was developed to address the gaps. Policies were established around student participation in clinical and return to work practices for staff with any symptoms. Conclusion: In hospitals there is above average risk for exposure to infectious diseases. Student nurses travel between hospital and university, with the capacity to act as a conduit of pathogens to large, susceptible populations. Nursing colleges must respond thoroughly to protect students and staff and prevent spread of disease into the university community in the midst of an epidemic. © Stirling et al.; licensee BioMed Central.

Respiratory tract infections in the military environment

Military personnel fighting in contemporary battlefields as well as those participating in combat training are at risk of contracting respiratory infections. Epidemiological studies have demonstrated that soldiers deployed to the harsh environment have higher rates of newly reported respiratory symptoms than non-deployers. Acute respiratory diseases are the principle reason for outpatient treatment and hospitalization among military personnel, with an incidence exceeding that of the adult civilian population by up to three-fold. Adenoviruses, influenza A and B viruses, Streptococcus pneumoniae, Streptococcus pyogenes, coronaviruses and rhinoviruses have been identified as the main causes of acute respiratory infections among the military population. Although infective pathogens have been extensively studied, a significant proportion of illnesses (over 40%) have been due to unknown causative agents. Other health hazards, which can lead to respiratory illnesses among troops, are extreme air temperatures, desert dust, emissions from burn pits, industrial pollutants, and airborne contaminants originating from degraded soil. Limited diagnostic capabilities, especially inside the area of operations, make it difficult to accurately estimate the exact number of respiratory diseases in the military environment. The aim of the study was to discuss the occurrence of respiratory tract infections in army personnel, existing risk factors and preventive measures. © 2014 Elsevier B.V.

Livestock trade networks for guiding animal health surveillance

Background: Trade in live animals can contribute to the introduction of exotic diseases, the maintenance and spread endemic diseases. Annually millions of animals are moved across Europe for the purposes of breeding, fattening and slaughter. Data on the number of animals moved were obtained from the Directorate General Sanco (DG Sanco) for 2011. These were converted to livestock units to enable direct comparison across species and their movements were mapped, used to calculate the indegrees and outdegrees of 27 European countries and the density and transitivity of movements within Europe. This provided the opportunity to discuss surveillance of European livestock movement taking into account stopping points en-route. Results: High density and transitivity of movement for registered equines, breeding and fattening cattle, breeding poultry and pigs for breeding, fattening and slaughter indicates that hazards have the potential to spread quickly within these populations. This is of concern to highly connected countries particularly those where imported animals constitute a large proportion of their national livestock populations, and have a high indegree. The transport of poultry (older than 72hours) and unweaned animals would require more rest breaks than the movement of weaned animals, which may provide more opportunities for disease transmission. Transitivity is greatest for animals transported for breeding purposes with cattle, pigs and poultry having values of over 50%. Conclusions: This paper demonstrated that some species (pigs and poultry) are traded much more frequently and at a larger scale than species such as goats. Some countries are more vulnerable than others due to importing animals from many countries, having imported animals requiring rest-breaks and importing large proportions of their national herd or flock. Such knowledge about the vulnerability of different livestock systems related to trade movements can be used to inform the design of animal he

Public preferences for vaccination and antiviral medicines under different pandemic flu outbreak scenarios

Background: During the 2009-2010 A(H1N1) pandemic, many people did not seek care quickly enough, failed to take a full course of antivirals despite being authorised to receive them, and were not vaccinated. Understanding facilitators and barriers to the uptake of vaccination and antiviral medicines will help inform campaigns in future pandemic influenza outbreaks. Increasing uptake of vaccines and antiviral medicines may need to address a range of drivers of behaviour. The aim was to identify facilitators of and barriers to being vaccinated and taking antiviral medicines in uncertain and severe pandemic influenza scenarios using a theoretical model of behaviour change, COM-B. Methods: Focus groups and interviews with 71 members of the public in England who varied in their at-risk status. Participants responded to uncertain and severe scenarios, and to messages giving advice on vaccination and antiviral medicines. Data were thematically analysed using the theoretical framework provided by the COM-B model. Results: Influences on uptake of vaccines and antiviral medicines - capabilities, motivations and opportunities - are part of an inter-related behavioural system and different components influenced each other. An identity of being healthy and immune from infection was invoked to explain feelings of invulnerability and hence a reduced need to be vaccinated, especially during an uncertain scenario. The identity of being a 'healthy person' also included beliefs about avoiding medicine and allowing the body to fight disease 'naturally'. This was given as a reason for using alternative precautionary behaviours to vaccination. This identity could be held by those not at-risk and by those who were clinically at-risk. Conclusions: Promoters and barriers to being vaccinated and taking antiviral medicines are multi-dimensional and communications to promote uptake are likely to be most effective if they address several components of behaviour. The benefit of using the COM-B mo

Detection of influenza-like illness aberrations by directly monitoring Pearson residuals of fitted negative binomial regression models

Background: Emerging novel influenza outbreaks have increasingly been a threat to the public and a major concern of public health departments. Real-time data in seamless surveillance systems such as health insurance claims data for influenza-like illnesses (ILI) are ready for analysis, making it highly desirable to develop practical techniques to analyze such readymade data for outbreak detection so that the public can receive timely influenza epidemic warnings. This study proposes a simple and effective approach to analyze area-based health insurance claims data including outpatient and emergency department (ED) visits for early detection of any aberrations of ILI. Methods: The health insurance claims data during 2004-2009 from a national health insurance research database were used for developing early detection methods. The proposed approach fitted the daily new ILI visits and monitored the Pearson residuals directly for aberration detection. First, negative binomial regression was used for both outpatient and ED visits to adjust for potentially influential factors such as holidays, weekends, seasons, temporal dependence and temperature. Second, if the Pearson residuals exceeded 1.96, aberration signals were issued. The empirical validation of the model was done in 2008 and 2009. In addition, we designed a simulation study to compare the time of outbreak detection, non-detection probability and false alarm rate between the proposed method and modified CUSUM. Results: The model successfully detected the aberrations of 2009 pandemic (H1N1) influenza virus in northern, central and southern Taiwan. The proposed approach was more sensitive in identifying aberrations in ED visits than those in outpatient visits. Simulation studies demonstrated that the proposed approach could detect the aberrations earlier, and with lower non-detection probability and mean false alarm rate in detecting aberrations compared to modified CUSUM methods. Conclusions: The proposed simple app

Derivation and Internal Validation of the Ebola Prediction Scorefor Risk Stratification of Patients With Suspected EbolaVirusDisease

Study objective: The current outbreak of Ebola virus disease in West Africa is the largest on record and has overwhelmed the capacity of local health systems and the international community to provide sufficient isolation and treatment of all suspected cases. The goal of this study is to develop a clinical prediction model that can help clinicians risk-stratify patients with suspected Ebola virus disease in the context of such an epidemic. Methods: A retrospective analysis was performed of patient data collected during routine clinical care at the Bong County Ebola Treatment Unit in Liberia during its first 16 weeks of operation. The predictive power of 14 clinical and epidemiologic variables was measured against the primary outcome of laboratory-confirmed Ebola virus disease, using logistic regression to develop a final prediction model. Bootstrap sampling was used to assess the internal validity of the model and estimate its performance in a simulated validation cohort. Results: Ebola virus disease testing results were available for 382 (97%) of 395 patients admitted to the Ebola treatment unit during the study period. A total of 160 patients (42%) tested positive for Ebola virus disease. Logistic regression analysis identified 6 variables independently predictive of laboratory-confirmed Ebola virus disease, including sick contact, diarrhea, loss of appetite, muscle pains, difficulty swallowing, and absence of abdominal pain. The Ebola Prediction Score, constructed with these 6 variables, had an area under the receiver operator characteristic curve of 0.75 (95% confidence interval 0.70 to 0.80) for the prediction of laboratory-confirmed Ebola virus disease. Patients with higher Ebola Prediction Scores had higher likelihoods of laboratory-confirmed Ebola virus disease. Conclusion: The Ebola Prediction Score can be used by clinicians as an adjunct to current Ebola virus disease case definitions to risk-stratify patients with suspected Ebola virus disease. Clinicians

Resilient information networks for coordination of foodborne disease outbreaks

Foodborne disease outbreaks are increasingly being seen as a greater concern by public health authorities. It has also become a global research agenda to identify improved pathways to coordinating outbreak detection. Furthermore, a significant need exists for timely coordination of the detection of potential foodborne disease outbreaks to reduce the number of infected individuals and the overall impact on public health security. This study aimed to offer an effective approach for coordinating foodborne disease outbreaks. First, we identify current coordination processes, complexities, and challenges. We then explore social media surveillance strategies, usage, and the power of these strategies to influence decision-making. Finally, based on informal (social media) and formal (organizational) surveillance approaches, we propose a hybrid information network model for improving the coordination of outbreak detection. Copyright © 2015 Society for Disaster Medicine and Public Health, Inc.

A practical approach to designing syndromic surveillance systems for livestock and poultry

The field of animal syndromic surveillance (SyS) is growing, with many systems being developed worldwide. Now is an appropriate time to share ideas and lessons learned from early SyS design and implementation. Based on our practical experience in animal health SyS, with additions from the public health and animal health SyS literature, we put forward for discussion a 6-step approach to designing SyS systems for livestock and poultry.The first step is to formalise policy and surveillance goals which are considerate of stakeholder expectations and reflect priority issues (1). Next, it is important to find consensus on national priority diseases and identify current surveillance gaps. The geographic, demographic, and temporal coverage of the system must be carefully assessed (2). A minimum dataset for SyS that includes the essential data to achieve all surveillance objectives while minimizing the amount of data collected should be defined. One can then compile an inventory of the data sources available and evaluate each using the criteria developed (3). A list of syndromes should then be produced for all data sources. Cases can be classified into syndrome classes and the data can be converted into time series (4). Based on the characteristics of the syndrome-time series, the length of historic data available and the type of outbreaks the system must detect, different aberration detection algorithms can be tested (5). Finally, it is essential to develop a minimally acceptable response protocol for each statistical signal produced (6).Important outcomes of this pre-operational phase should be building of a national network of experts and collective action and evaluation plans. While some of the more applied steps (4 and 5) are currently receiving consideration, more emphasis should be put on earlier conceptual steps by decision makers and surveillance developers (1-3). © 2014 Elsevier B.V.

Emerging infectious disease (EID) communication during the 2009 H1N1 influenza outbreak: Literature review (2009-2013) of the methodology used for EID communication analysis

Objective This year alone has seen outbreaks of epidemics such as Ebola, Chikungunya, and many other emerging infectious diseases (EIDs). We must look to the responses of recent outbreaks to help guide our strategies in current and future outbreaks or we risk repeating the same mistakes. The objective of this paper was to conduct a systematic literature review of the methodology used by studies that examined EID communication during the 2009 H1N1 pandemic outbreak through different communication channels or by analyzing contents and strategies. Methods This was a systematic review of the literature (n=61) studying risk communication strategies of H1N1 influenza, published between 2009 and 2013, and retrieved from searches of computerized databases, hand searches, and authoritative texts by use of specific search criteria. Searches were followed by review, categorization, and mixed qualitative and quantitative content analysis. Results Of 41 articles that used quantitative methods, most used surveys (n=35); some employed content analyses (n=4) and controlled trials (n=2). The 16 articles that employed qualitative methods relied on content analyses (n=10), semi-structured interviews (n=2) and focus groups (n=4). Four more articles used mixed-methods or nonstandard methods. Seven different topic categories were found: risk perception and effects on behaviors, framing the risk in the media, public concerns, trust, optimistic bias, uncertainty, and evaluating risk communication. Conclusions Up until 2013, studies tended to be descriptive and quantitative rather than discursive and qualitative and to focus on the role of the media as representing information and not as a medium for actual communication with the public. Several studies from 2012, and increasingly more in 2013, addressed issues of discourse and framing and the complexity of risk communication with the public. Formative evaluations that use recommendations from past research when designing communication camp

Networks of preparedness and response during Australian H1N1 outbreak

Objective New theoretical and practical approaches were used to determine the outcome of complex interorganizational networks during the 2009 H1N1 outbreak in Australia. Methods Seventy health professionals from different skill sets and organizational positions who participated in the 2009 swine influenza H1N1 outbreak in Australia were surveyed. Interviews were designed to collect both qualitative and quantitative data to build a comprehensive and in-depth understanding of the dynamics of interorganizational networks that evolve during the coordinated response to the H1N1 outbreak. Three main components of network theory, ie, degree centrality, connectedness, and tie strength, were used to construct a performance model for assessing networks of preparedness and response. Results We observed that increasing communication frequency and diversifying the tiers of the interorganizational links enhanced the overall network's performance in the case of formal coordination. Network measures such as centrality, connectedness, and tie strength were relevant and resulted in improving the entire network's performance during the outbreak. Conclusion In the context of a disease outbreak in a complex environment and a large geographical area, this investigation has provided a new perspective for understanding how the structure of a collaborative network of personnel affects the performance of the overall network. Copyright © 2015 Society for Disaster Medicine and Public Health, Inc.

Transmission and effect of multiple clusters of seasonal influenza in a swiss geriatric hospital

Objectives To investigate a nosocomial outbreak of influenza. Design Prospective outbreak investigation with active case finding and molecular typing. Setting A large academic geriatric hospital in Switzerland. Participants Elderly hospitalized adults. Measurements Based on syndromic surveillance, a nosocomial influenza outbreak was suspected in February 2012. All suspected cases were screened for respiratory viruses using real-time reverse transcription polymerase chain reaction of nasopharyngeal swabs. Infection control procedures (droplet precautions with single room isolation whenever possible) were implemented for all suspected or confirmed cases. Specimens positive for influenza viruses were processed and sequenced whenever possible to track transmission dynamics. Results Respiratory samples from 155 suspected cases were analyzed during the outbreak period, of which 69 (44%) were positive for influenza virus, 26 (17%) were positive for other respiratory viruses, and 60 (39%) were negative. Three other cases fulfilled clinical criteria for influenza infection but were not sampled, and one individual was admitted with an already positive test, resulting in a total of 73 influenza cases, of which 62 (85%) were classified as nosocomial. Five distinct clusters of nosocomial transmission were identified using viral sequencing, with epidemiologically unexpected in-hospital transmission dynamics. Seven of 23 patients who experienced influenza complications died. Sixteen healthcare workers experienced an influenza-like illness (overall vaccination rate, 36%). Conclusion Nosocomial influenza transmission caused more secondary cases than repeated community importation during this polyclonal outbreak. Molecular tools revealed complex transmission dynamics. Low healthcare worker vaccination rates and gaps in recommended infection control procedures are likely to have contributed to nosocomial spread of influenza, which remains a potentially life-threatening disease in elde

A rationale to unify measurements of effectiveness for animal health surveillance

Surveillance systems produce data which, once analysed and interpreted, support decisions regarding disease management. While several performance measures for surveillance are in use, no theoretical framework has been proposed yet with a rationale for defining and estimating effectiveness measures of surveillance systems in a generic way. An effective surveillance system is a system whose data collection, analysis and interpretation processes lead to decisions that are appropriate given the true disease status of the target population. Accordingly, we developed a framework accounting for sampling, testing and data interpretation processes, to depict in a probabilistic way the direction and magnitude of the discrepancy between "decisions that would be made if the true state of a population was known" and the "decisions that are actually made upon the analysis and interpretation of surveillance data". The proposed framework provides a theoretical basis for standardised quantitative evaluation of the effectiveness of surveillance systems. We illustrate such approaches using hypothetical surveillance systems aimed at monitoring the prevalence of an endemic disease and at detecting an emerging disease as early as possible and with an empirical case study on a passive surveillance system aiming at detecting cases of Highly Pathogenic Avian Influenza cases in Vietnamese poultry. © 2015 Elsevier B.V.

Public risk perceptions and preventive behaviors during the 2009 H1N1 influenza pandemic

Objective This study examines the public perception of the 2009 H1N1 influenza risk and its association with flu-related knowledge, social contexts, and preventive behaviors during the second wave of the influenza outbreak in Arizona. Methods Statistical analyses were conducted on survey data, which were collected from a random-digit telephone survey of the general public in Arizona in October 2009. Results The public perceived different levels of risk regarding the likelihood and their concern about contracting the 2009 H1N1 flu. These measures of risk perception were primarily correlated with people of Hispanic ethnicity, having children in the household, and recent seasonal flu experience in the previous year. The perceived likelihood was not strongly associated with preventive behaviors, whereas the perceived concern was significantly associated with precautionary and preparatory behaviors. The association between perceived concern and precautionary behavior persisted after controlling for demographic characteristics. Conclusions Pandemic preparedness and response efforts need to incorporate these findings to help develop effective risk communication strategies that properly induce preventive behaviors among the public. Copyright © 2015 Society for Disaster Medicine and Public Health, Inc.

Detection of influenza vaccine effectiveness among nursery school children: Lesson from a season with cocirculating respiratory syncytial virus

In the winter influenza epidemic season, patients with respiratory illnesses including respiratory syncytial virus (RSV) infections increase among young children. Therefore, we evaluated the effectiveness of influenza vaccine against influenza-like illness (ILI) using a technique to identify outbreaks of RSV infection and to distinguish those patients from ILI patients. The study subjects were 101 children aged 12 to 84 months attending nursery school. We classified the cases into 6 levels based on the definitions of ILI for outcomes. We established observation periods according to information obtained from regional surveillance and rapid diagnostic tests among children. Multivariate odds ratios (ORs) for each case classification were obtained using a logistic regression model for each observation period. For the entire observation period, ORs for cases with fever plus respiratory symptoms were reduced marginally significantly. For the local influenza epidemic period, only the OR for the most serious cases was significantly decreased (0.20 [95%CI: 0.04-0.94]). During the influenza outbreak among the nursery school children, multivariate ORs for fever plus respiratory symptoms decreased significantly (? 38.0°C plus ? one symptoms: 0.23 [0.06-0.91), ? 38.0°C plus ? 2 symptoms: 0.21 [0.05-0.85], ? 39.0°C plus ? one symptoms: 0.18 [0.04-0.93] and ? 39.0°C plus ? 2 symptoms: 0.16 [0.03-0.87]). These results suggest that confining observation to the peak influenza epidemic period and adoption of a strict case classification system can minimize outcome misclassification when evaluating the effectiveness of influenza vaccine against ILI, even if influenza and RSV cocirculate in the same season. © 2015 Taylor & Francis Group, LLC.

Perceptions and behavioral responses of the general public during the 2009 influenza A (H1N1) pandemic: A systematic review

The public plays an important role in controlling the spread of a virus by adopting preventive measures. This systematic literature review aimed to gain insight into public perceptions and behavioral responses to the 2009 influenza A (H1N1) pandemic, with a focus on trends over time and regional differences. We screened 5498 articles and identified 70 eligible studies from PubMed, Embase, and PsychINFO. Public misconceptions were apparent regarding modes of transmission and preventive measures. Perceptions and behaviors evolved during the pandemic. In most countries, perceived vulnerability increased, but perceived severity, anxiety, self-efficacy, and vaccination intention decreased. Improved hygienic practices and social distancing were practiced most commonly. However, vaccination acceptance remained low. Marked regional differences were noted. To prevent misconceptions, it is important that health authorities provide up-to-date information about the virus and possible preventive measures during future outbreaks. Health authorities should continuously monitor public perceptions and misconceptions. Because public perceptions and behaviors varied between countries during the pandemic, risk communication should be tailored to the specific circumstances of each country. Finally, the use of health behavior theories in studies of public perceptions and behaviors during outbreaks would greatly facilitate the development of effective public health interventions that counter the effect of an outbreak. Copyright © 2015 Society for Disaster Medicine and Public Health, Inc.

Spread and persistence of influenza A viruses in waterfowl hosts in the North American Mississippi migratory flyway

While geographic distance often restricts the spread of pathogens via hosts, this barrier may be compromised when host species are mobile. Migratory waterfowl in the order Anseriformes are important reservoir hosts for diverse populations of avian-origin influenza A viruses (AIVs) and are assumed to spread AIVs during their annual continental-scale migrations. However, support for this hypothesis is limited, and it is rarely tested using data from comprehensive surveillance efforts incorporating both the temporal and spatial aspects of host migratory patterns. We conducted intensive AIV surveillance of waterfowl using the North American Mississippi Migratory Flyway (MMF) over three autumn migratory seasons. Viral isolates (n = 297) from multiple host species were sequenced and analyzed for patterns of gene dispersal between northern staging and southern wintering locations. Using a phylogenetic and nucleotide identity framework, we observed a larger amount of gene dispersal within this flyway rather than between the other three longitudinally identified North American flyways. Across seasons, we observed patterns of regional persistence of diversity for each genomic segment, along with limited survival of dispersed AIV gene lineages. Reassortment increased with both time and distance, resulting in transient AIV constellations. This study shows that within the MMF, AIV gene flow favors spread along the migratory corridor within a season, and also that intensive surveillance during bird migration is important for identifying virus dispersal on time scales relevant to pandemic responsiveness. In addition, this study indicates that comprehensive monitoring programs to capture AIV diversity are critical for providing insight into AIV evolution and ecology in a major natural reservoir. © 2015, American Society for Microbiology.

Immune responses of wild birds to emerging infectious diseases

Summary: Over the past several decades, outbreaks of emerging infectious diseases (EIDs) in wild birds have attracted worldwide media attention, either because of their extreme virulence or because of alarming spillovers into agricultural animals or humans. The pathogens involved have been found to infect a variety of bird hosts ranging from relatively few species (e.g. Trichomonas gallinae) to hundreds of species (e.g. West Nile Virus). Here we review and contrast the immune responses that wild birds are able to mount against these novel pathogens. We discuss the extent to which these responses are associated with reduced clinical symptoms, pathogen load and mortality, or conversely, how they can be linked to worsened pathology and reduced survival. We then investigate how immune responses to EIDs can evolve over time in response to pathogen-driven selection using the illustrative case study of the epizootic outbreak of Mycoplasma gallisepticum in wild North American house finches (Haemorhous mexicanus). We highlight the need for future work to take advantage of the substantial inter- and intraspecific variation in disease progression and outcome following infections with EID to elucidate the extent to which immune responses confer increased resistance through pathogen clearance or may instead heighten pathogenesis. © 2015 John Wiley & Sons Ltd.

Epidemic spreading and global stability of an SIS model with an infective vector on complex networks

In this paper, we present a new SIS model with delay on scale-free networks. The model is suitable to describe some epidemics which are not only transmitted by a vector but also spread between individuals by direct contacts. In view of the biological relevance and real spreading process, we introduce a delay to denote average incubation period of disease in a vector. By mathematical analysis, we obtain the epidemic threshold and prove the global stability of equilibria. The simulation shows the delay will effect the epidemic spreading. Finally, we investigate and compare two major immunization strategies, uniform immunization and targeted immunization. © 2015 Elsevier B.V.

Optimal vaccination policy and cost analysis for epidemic control in resource-limited settings

Purpose - The purpose of this paper is to use analytical method and optimization tools to suggest time-optimal vaccination program for a basic SIR epidemic model with mass action contact rate when supply is limited. Design/methodology/approach - The Lagrange Multiplier Method and Pontryagin's Maximum Principle are used to explore optimal control strategy and obtain analytical solution for the control system to minimize the total cost of disease with boundary constraint. The numerical simulation is done with Matlab using the sequential linear programming method to illustrate the impact of parameters. Findings - The result highlighted that the optimal control strategy is Bang-Bang control - to vaccinate with maximal effort until either all of the resources are used up or epidemic is over, and the optimal strategies and total cost of vaccination are usually dependent on whether there is any constraint of resource, however, the optimal strategy is independent on the relative cost of vaccination when the supply is limited. Practical implications - The research indicate a practical view that the enhancement of daily vaccination rate is critical to make effective initiatives to prevent epidemic from out breaking and reduce the costs of control. Originality/value - The analysis of the time-optimal application of outbreak control is of clear practical value and the introducing of resource constraint in epidemic control is of realistic sense, these are beneficial for epidemiologists and public health officials. © Emerald Group Publishing Limited.

Factors associated with hospitalization for blood-borne viral infections among treatment-seeking illicit drug users

Blood-borne viral infections (BBVIs) are important health consequences of illicit drug use. This study assessed predictors of inpatient hospital admissions for BBVIs in a cohort of 4817 clients seeking treatment for drug use in Finland. We examined clients' data on hospital admissions registered in the Finnish National Hospital Discharge Register from 1997 to 2010 with diagnoses of BBVIs. Cox proportional hazards regression analyses were separately conducted for each of the three BBVI groups to test for association between baseline variables and hospitalizations. Findings were reported as adjusted hazard ratios (aHRs). Based upon primary discharge diagnoses, 81 clients were hospitalized for HIV, 116 for hepatitis C, and 45 for other types of hepatitis. Compared to those admitted for hepatitis C and other hepatitis, drug users with HIV had higher total number of hospital admissions (294 versus 141 and 50 respectively), higher crude hospitalization rate (7.1 versus 3.4.and 1.2 per 1000 person-years respectively), and higher total length of hospital stay (2857 days versus 279 and 308 respectively). Trends in hospitalization for all BBVI groups declined at the end of follow-up. HIV positive status at baseline (aHR: 6.58) and longer duration of drug use (aHR: 1.11) were independently associated with increased risk for HIV hospitalization. Female gender (aHR: 3.05) and intravenous use of primary drug (aHR: 2.78) were significantly associated with HCV hospitalization. Having hepatitis B negative status at baseline (aHR: 0.25) reduced the risk of other hepatitis hospitalizations. Illicit drug use coexists with blood-borne viral infections. To address this problem, clinicians treating infectious diseases need to also identify drug use in their patients and provide drug treatment information and/or referral. © 2015 Elsevier Inc.

Risk communication during the 2009 influenza A (H1N1) pandemic: Stakeholder experiences from eight European countries

Objective We aimed to assess professional stakeholders' perceptions of the risk-communication difficulties faced during the 2009 influenza A (H1N1) pandemic in Europe. Methods Semi-structured interviews were conducted with experts involved in the management of the 2009 swine flu pandemic from different European countries. The interviews were recorded, transcribed, and coded. Results A total of 25 experts from 8 European countries were interviewed: 9 from the micro-level, 10 from the meso-level, and 6 from the macro-level of employment. The interviews revealed 3 main themes: vaccine issues, communication issues, and general problems. As reasons for the low vaccination coverage, stakeholders mentioned the late arrival of the vaccines, the moderate character of the pandemic, vaccine safety concerns, and a general skepticism toward vaccination. Communication needs varied between the different levels of employment: macro- and meso-level stakeholders preferred fast information but from multiple sources; the micro-level stakeholders preferred one credible source. Throughout Europe, collaboration with the media was perceived as poor and professionals felt misunderstood. Conclusions Professional stakeholders should be enabled to access reliable information rapidly through preestablished channels; emphasis should be placed on establishing sustainable cooperations between experts and the media; and measures to improve trust in health authorities, such as the transparent communication of uncertainties, should be encouraged. Copyright © 2015 Society for Disaster Medicine and Public Health, Inc.

Quantitative and qualitative assessment of the bovine abortion surveillance system in France

Bovine abortion is the main clinical sign of bovine brucellosis, a disease of which France has been declared officially free since 2005. To ensure the early detection of any brucellosis outbreak, event-driven surveillance relies on the mandatory notification of bovine abortions and the brucellosis testing of aborting cows. However, the under-reporting of abortions appears frequent. Our objectives were to assess the aptitude of the bovine abortion surveillance system to detect each and every bovine abortion and to identify factors influencing the system's effectiveness. We evaluated five attributes defined by the U.S. Centers for Disease Control with a method suited to each attribute: (1) data quality was studied quantitatively and qualitatively, as this factor considerably influences data analysis and results; (2) sensitivity and representativeness were estimated using a unilist capture-recapture approach to quantify the surveillance system's effectiveness; (3) acceptability and simplicity were studied through qualitative interviews of actors in the field, given that the surveillance system relies heavily on abortion notifications by farmers and veterinarians. Our analysis showed that (1) data quality was generally satisfactory even though some errors might be due to actors' lack of awareness of the need to collect accurate data; (2) from 2006 to 2011, the mean annual sensitivity - i.e. the proportion of farmers who reported at least one abortion out of all those who detected such events - was around 34%, but was significantly higher in dairy than beef cattle herds (highlighting a lack of representativeness); (3) overall, the system's low sensitivity was related to its low acceptability and lack of simplicity. This study showed that, in contrast to policy-makers, most farmers and veterinarians perceived the risk of a brucellosis outbreak as negligible. They did not consider sporadic abortions as a suspected case of brucellosis and usually reported abortions only to

A novel response to an outbreak of infectious syphilis in Christchurch, New Zealand

During 2012, Christchurch experienced a dramatic increase in cases of infectious syphilis among men who have sex with men. This was accompanied by some novel trends; notably, the acquisition of infection in a younger age group, with local sexual contacts, commonly via the use of social media. This study is a report on an approach to case identification and public health communication as a component of a multifaceted outbreak response. Enhanced syphilis surveillance data on public health responses to outbreaks of sexually transmissible infections was collated and reviewed, alongside clinical records and literature. Reported outbreak response methods were adapted for the Christchurch cohort. A Facebook page was created to raise awareness of infectious syphilis, the importance of screening and where to get tested. Twenty-six males were diagnosed with infectious syphilis in 2012, an increase from previous years, of which 22 reported only male sexual contact. High use of social media used to find potential sexual contacts was reported. Enhanced syphilis surveillance characterised in detail an infectious syphilis outbreak in Christchurch. Index cases were identified, contact tracing mapping was used to identify transmission networks and social media was also used to educate the risk group. There was a decrease in infectious syphilis presentations, with no cases in the last 3 months of 2012. © CSIRO 2015.

The livestock reservoir for antimicrobial resistance: A personal view on changing patterns of risks, effects of interventions and the way forward

The purpose of this review was to provide an updated overview on the use of antimicrobial agents in livestock, the associated problems for humans and current knowledge on the effects of reducing resistance in the livestock reservoir on both human health and animal production. There is still limiting data on both use of antimicrobial agents, occurrence and spread of resistance as well as impact on human health. However, in recent years, emerging issues related to methicillin-resistant Staphylococcus aureus, Clostridium difficile, Escherichia coli and horizontally transferred genes indicates that the livestock reservoir has a more significant impact on human health than was estimated 10 years ago, where the focus was mainly on resistance in Campylobacter and Salmonella. Studies have indicated that there might only be a marginal if any benefit from the regular use of antibiotics and have shown that it is possible to substantially reduce the use of antimicrobial agents in livestock production without compromising animal welfare or health or production. In some cases, this should be done in combination with other measures such as biosecurity and use of vaccines. To enable better studies on both the global burden and the effect of interventions, there is a need for global harmonized integrated and continuous surveillance of antimicrobial usage and antimicrobial resistance, preferably associated with data on production and animal diseases to determine the positive and negative impact of reducing antimicrobial use in livestock. © 2015 The Author(s).

Evolution of the syphilis epidemic among men who have sex with men

Syphilis has existed for millenni, but its epidemiology was only recently linked to men who have sex with men (MSM) after the introduction of penicillin in the 1940s; the syphilis epidemic became concentrated within the MSM community in subsequent decades. The HIV/AIDS epidemic in the 1980s led to a surge of new syphilis cases and revealed the potentiation between HIV and syphilis, as evidenced by a shift in the natural history of neurosyphilis. In response, MSM revolutionised their sexual behaviour by implementing community-driven seroadaptive strategies to stem HIV transmission. The Centers for Disease Control in the US called for the elimination of syphilis in the late 1990s since the rates had fallen sharply but this effort was overtaken by a resurgence of global outbreaks among MSM in the 2000s, many of which were linked to methamphetamine use and sexual networking websites. Syphilis remains highly prevalent today, especially among MSM and individuals infected with HIV, and it continues to present a significant public health conundrum. Innovative syphilis prevention strategies are warranted. MSM engaging in high-risk behaviour such as condomless anal receptive intercourse, sex with multiple partners or recreational drug use should be routinely screened for syphilis infection; they should also be counselled about the limits of seroadaptive behaviours and HIV pre-exposure prophylaxis as they relate to syphilis transmission. © CSIRO 2015.

Internet activity as a proxy for vaccination compliance

Tracking the progress of vaccination campaigns is a challenging and important public health need. Examining a recent Polio outbreak in the Middle East, we show that novel methods utilizing online search trends have great potential to provide a real-time, reliable proxy for vaccination rates over space and time. © 2015 Elsevier Ltd.

Pertussis models to inform vaccine policy

Pertussis remains a challenging public health problem with many aspects of infection, disease and immunity poorly understood. Initially controlled by mass vaccination, pertussis resurgence has occurred in some countries with wellestablished vaccination programs, particularly among adolescents and young adults. Several studies have used mathematical models to investigate drivers of pertussis epidemiology and predict the likely impact of different vaccination strategies. We reviewed a number of these models to evaluate their suitability to answer questions of public health importance regarding optimal vaccine scheduling. We critically discuss the approaches adopted and the impact of chosen model structures and assumptions on study conclusions. Common limitations were a lack of contemporary, population relevant data for parameterization and a limited understanding of the relationship between infection and disease. We make recommendations for future model development and suggest epidemiologic data collections that would facilitate efforts to reduce uncertainty and improve the robustness of model-derived conclusions. © 2015 Taylor & Francis Group, LLC.

Potential impact of climatic variability on the epidemiology of dengue in Risaralda, Colombia, 2010-2011

Dengue continues to be the most important viral vector-borne disease in the world, particularly in Asia and Latin America, and is significantly affected by climate variability. The influence of climate in an endemic region of Colombia, from 2010 to 2011, was assessed. Epidemiological surveillance data (weekly cases) were collected, and incidence rates were calculated. Poisson regression models were used to assess the influence of the macroclimatic variable ONI (Oscillation Niño Index) and the microclimatic variable pluviometry (mm of rain for Risaralda) on the dengue incidence rate, adjusting by year and week. During the study period, 13,650 cases were reported. In 2010, the rates ranged from 8.6 cases/100,000 pop. up to a peak of 75.3 cases/100,000 pop. for a cumulative rate of 456.2 cases/100,000 pop. in that week. The climate variability in 2010 was higher (ONI 1.6, El Niño to -1.5, La Niña) than in 2011 (ONI -1.4, La Niña to -0.2, Neutral). The mean pluviometry was 248.45mm (min 135.9-max 432.84). During El Niño, cases were significantly higher (mean 433.81) than during the climate neutral period (142.48) and during the La Niña (52.80) phases (ANOVA F=66.59; p<0.001). Regression models showed that the ONI (coefficient 0.329; 95%CI 0.209-0.450) and pluviometry (coefficient 0.003; 95%CI 0.002-0.004) were highly significant independent variables associated with dengue incidence rate, after adjusting by year and week (p<0.001, pseudo r2=0.6913). El Niño significantly affected the incidence of dengue in Risaralda. This association with climate change and variability should be considered in the elements influencing disease epidemiology. In addition, predictive models should be developed further with more available data from disease surveillance. © 2014 King Saud Bin Abdulaziz University for Health Sciences.

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