WorldWideScience

Sample records for hypothetical disease epidemics

  1. The Impact of Resources for Clinical Surveillance on the Control of a Hypothetical Foot-and-Mouth Disease Epidemic in Denmark

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette

    2014-01-01

    The objectives of this study were to assess whether current surveillance capacity is sufficient to fulfill EU and Danish regulations to control a hypothetical foot-and-mouth disease (FMD) epidemic in Denmark, and whether enlarging the protection and/or surveillance zones could minimize economic...

  2. [Epidemic parotiditis, a reportable disease].

    Science.gov (United States)

    Boverhoff, J C; Baart, J A

    2013-01-01

    Three consecutive patients with an acute swelling of one of the cheeks, were diagnosed with epidemic parotiditis. The first phase of the diagnostic procedure for an acute cheek swelling is to eliminate the possibility of odontogenic causes. When odontogenic problems have been excluded, non-dentition-related causes may be considered. An acute, progressive swelling in the preauricular area can often be attributed to an inflammation of the parotid gland, but epidemic parotiditis should also be considered. Epidemic parotiditis, or mumps, is caused by the mumps virus. Contamination occurs aerogenically. In the Netherlands, mumps vaccine is an ingredient of the governmental combined mump-measles-rubella inoculation programme. However, in recent years several small-scale parotiditis epidemics have broken out, predominantly among young, inoculated adults. Oropharyngeal mucus and blood samples are needed to diagnose the disease. Each case of the disease should be reported to the community healthcare service.

  3. [Aluminum, hypothetic cause of Alzheimer disease].

    Science.gov (United States)

    Pailler, F M; Bequet, D; Corbé, H; Giudicelli, C P

    1995-03-11

    A great deal of research has focused on aluminium as a putative causative factor in Alzheimer's disease. We measured by atomic absorption spectrophotometry aluminium levels in blood, urine and cerebrospinal fluid from 15 patients with Alzheimer's disease, compared with 20 control individuals. There were no statistically significant differences between the two groups. This suggests that aluminium is not a causative factor for Alzheimer's disease.

  4. The Economics of Epidemic Diseases.

    Science.gov (United States)

    Dimitri, Nicola

    2015-01-01

    Epidemic, infectious, diseases affect a large number of individuals across developing as well as developed countries. With reference to some very simple diffusion models, in this paper we consider how available economic resources could be optimally allocated by health authorities to mitigate, possibly eradicate, the disease. Optimality was defined as the minimization of the long run number of infected people. The main goal of the work has been to introduce a methodology for deciding if it would be best to concentrate resources to prevent contact between individuals and with an external source, or to develop a new treatment for curing the disease, or both. The analysis suggests that this depends on the cost functions, that is the available technology, for controlling the relevant parameters underlying the epidemics as well as on the available financial resources. In the case of the recent Ebola outbreak, the suggestions of the model have been consistent with the policies adopted.

  5. Impact of clinical surveillance during a foot-and-mouth disease epidemic

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette

    The objectives of this study were to assess, whether the current surveillance capacity is sufficient to fulfill EU and Danish regulations to control a hypothetical foot-and-mouth disease (FMD) epidemic in Denmark, and whether enlarging the protection and/or surveillance zones could reduce epidemic...

  6. Familial epidemic of meningococcal disease.

    Science.gov (United States)

    Smilović, V; Vrbanec-Megla, L; Payerl-Pal, M; Puntarić, D; Baklaić, Z

    1998-03-01

    Two closely related boys from the same house hold (Home 1), aged two and three, were affected with fulminant meningococcal sepsis known as Waterhouse-Friderichsen syndrome. Neisseria meningitidis serogorup B was isolated from their blood and cerebrospinal fluid. The two-year-old boy died one day after the onset of the disease. Epidemiological examination of contacts and pharyngeal swabs were performed in 14 persons from the household, all of them relatives of the affected children, as well as in a number of other contacts. Chemoprophylaxis with cotrimoxazole was simultaneously administered to all contacts. Family histories revealed that two contacts from the household where the patients did not live (Home 2) were inadvertently omitted. Subsequent examinations, following a report of another contagious disease (salmonelosis), revealed that these two persons were Neisseria meningitidis carriers, together with another one in the same household. The carriers most probably caused the infection of a third, five-year-old boy, the deceased boy's brother (Home 1) who also developed fulminant meningococcal sepsis. The failure to take the appropriate prophylaxis led to a prolonged carrier state in the carrier from the second household. Repeated pharyngeal swab sampling revealed two more carriers from both households that had previously been negative. Control of the epidemic was achieved after 5 weeks by repeated and controlled chemoprophylaxis with ciprofloxacin, and by repeated epidemiological examinations, disinfection, and daily health surveillance by the Sanitary Inspectorate. This extremely rare instance of a familial epidemic with three infected persons emphasizes the need for consistent chemoprophylaxis in meningococcal disease contacts.

  7. Impact of clinical surveillance during a foot-and-mouth disease epidemic

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette

    The objectives of this study were to assess, whether the current surveillance capacity is sufficient to fulfill EU and Danish regulations to control a hypothetical foot-and-mouth disease (FMD) epidemic in Denmark, and whether enlarging the protection and/or surveillance zones could reduce epidemic...... duration, number of infected herds and the economic losses from an epidemic. The stochastic spatial simulation model DTU-DADS was enhanced to include simulation of surveillance of herds within the protection and surveillance zones and the model was used to model spread of FMD between herds. A queuing...

  8. Obesity and kidney disease: hidden consequences of the epidemic

    African Journals Online (AJOL)

    Obesity has become a worldwide epidemic, and its prevalence has been projected to ... Keywords: chronic kidney disease, kidney cancer, nephrolithiasis, obesity, prevention ... kidney disease on the occasion of the 2017 World Kidney Day.

  9. Tuberculosis and Cardiovascular Disease: Linking the Epidemics.

    Science.gov (United States)

    Huaman, Moises A; Henson, David; Ticona, Eduardo; Sterling, Timothy R; Garvy, Beth A

    The burden of tuberculosis and cardiovascular disease (CVD) is enormous worldwide. CVD rates are rapidly increasing in low- and middle-income countries. Public health programs have been challenged with the overlapping tuberculosis and CVD epidemics. Monocyte/macrophages, lymphocytes and cytokines involved in cellular mediated immune responses against Mycobacterium tuberculosis are also main drivers of atherogenesis, suggesting a potential pathogenic role of tuberculosis in CVD via mechanisms that have been described for other pathogens that establish chronic infection and latency. Studies have shown a pro-atherogenic effect of antibody-mediated responses against mycobacterial heat shock protein-65 through cross reaction with self-antigens in human vessels. Furthermore, subsets of mycobacteria actively replicate during latent tuberculosis infection (LTBI), and recent studies suggest that LTBI is associated with persistent chronic inflammation that may lead to CVD. Recent epidemiologic work has shown that the risk of CVD in persons who develop tuberculosis is higher than in persons without a history of tuberculosis, even several years after recovery from tuberculosis. Together, these data suggest that tuberculosis may play a role in the pathogenesis of CVD. Further research to investigate a potential link between tuberculosis and CVD is warranted.

  10. Dynamics of epidemic diseases on a growing adaptive network

    Science.gov (United States)

    Demirel, Güven; Barter, Edmund; Gross, Thilo

    2017-02-01

    The study of epidemics on static networks has revealed important effects on disease prevalence of network topological features such as the variance of the degree distribution, i.e. the distribution of the number of neighbors of nodes, and the maximum degree. Here, we analyze an adaptive network where the degree distribution is not independent of epidemics but is shaped through disease-induced dynamics and mortality in a complex interplay. We study the dynamics of a network that grows according to a preferential attachment rule, while nodes are simultaneously removed from the network due to disease-induced mortality. We investigate the prevalence of the disease using individual-based simulations and a heterogeneous node approximation. Our results suggest that in this system in the thermodynamic limit no epidemic thresholds exist, while the interplay between network growth and epidemic spreading leads to exponential networks for any finite rate of infectiousness when the disease persists.

  11. Cost-effectiveness models for chronic obstructive pulmonary disease : cross-model comparison of hypothetical treatment scenarios

    NARCIS (Netherlands)

    Hoogendoorn, Martine; Feenstra, Talitha L; Asukai, Yumi; Borg, Sixten; Hansen, Ryan N; Jansson, Sven-Arne; Samyshkin, Yevgeniy; Wacker, Margarethe; Briggs, Andrew H; Lloyd, Adam; Sullivan, Sean D; Rutten-van Mölken, Maureen P M H

    2014-01-01

    OBJECTIVES: To compare different chronic obstructive pulmonary disease (COPD) cost-effectiveness models with respect to structure and input parameters and to cross-validate the models by running the same hypothetical treatment scenarios. METHODS: COPD modeling groups simulated four hypothetical inte

  12. Hypothetical Justifications

    Directory of Open Access Journals (Sweden)

    Bernd Lahno

    2009-01-01

    Full Text Available A basic conviction in moral non-cognitivism is: only hypothetical norms may be justified. Hartmut Kliemt argues for a moderate variant: there are only hypothetical justifications of norms whether the norms are hypothetical or categorical in kind. In this paper the concept of 'hypothetical justification' is analyzed. It is argued that hypothetical justifications are not of the kind that we should look for in normative ethics.

  13. Epidemic Intelligence. Langmuir and the Birth of Disease Surveillance

    Directory of Open Access Journals (Sweden)

    Lyle Fearnley

    2010-12-01

    Full Text Available In the wake of the SARS and influenza epidemics of the past decade, one public health solution has become a refrain: surveillance systems for detection of disease outbreaks. This paper is an effort to understand how disease surveillance for outbreak detection gained such paramount rationality in contemporary public health. The epidemiologist Alexander Langmuir is well known as the creator of modern disease surveillance. But less well known is how he imagined disease surveillance as one part of what he called “epidemic intelligence.” Langmuir developed the practice of disease surveillance during an unprecedented moment in which the threat of biological warfare brought civil defense experts and epidemiologists together around a common problem. In this paper, I describe how Langmuir navigated this world, experimenting with new techniques and rationales of epidemic control. Ultimately, I argue, Langmuir′s experiments resulted in a set of techniques and infrastructures – a system of epidemic intelligence – that transformed the epidemic as an object of human art.

  14. Chronic kidney disease – the silent epidemic

    African Journals Online (AJOL)

    2007-08-16

    Aug 16, 2007 ... kidney disease (CKD), which brings with it a huge burden of cardiovascular disease (CVD) ... preparation for renal replacement therapy. Most pathology ..... Health and Nutrition Examination Surveys. (NHANES III) revealed ...

  15. Siting epidemic disease: 3 centuries of American history.

    Science.gov (United States)

    Rosenberg, Charles E

    2008-02-15

    Epidemics of infectious disease have always played a role in American history, and such epidemics are sited in time and place and configured in terms of ecology and demography, available medical knowledge, and cultural values and collective experience. The mix of these variables has changed dramatically since the theocratic world of 17th-century New England, but the relevance of each remains. Avian influenza already exists virtually in Western society in terms of planning, global networks, laboratory research, social expectations, media representations, and a specific shared history based on the memory of the 1918 influenza pandemic.

  16. Disease-induced resource constraints can trigger explosive epidemics

    CERN Document Server

    Böttcher, Lucas; Araújo, Nuno A M; Herrmann, Hans J; Helbing, Dirk

    2015-01-01

    Advances in mathematical epidemiology have led to a better understanding of the risks posed by epidemic spreading and informed strategies to contain disease spread. However, a challenge that has been overlooked is that, as a disease becomes more prevalent, it can limit the availability of the capital needed to effectively treat those who have fallen ill. Here we use a simple mathematical model to gain insight into the dynamics of an epidemic when the recovery of sick individuals depends on the availability of healing resources that are generated by the healthy population. We find that epidemics spiral out of control into "explosive" spread if the cost of recovery is above a critical cost. This can occur even when the disease would die out without the resource constraint. The onset of explosive epidemics is very sudden, exhibiting a discontinuous transition under very general assumptions. We find analytical expressions for the critical cost and the size of the explosive jump in infection levels in terms of the...

  17. Preventing the Epidemic of Non-Communicable Diseases: An Overview

    OpenAIRE

    Robson, Anthony,

    2013-01-01

    International audience; Diet, lifestyle and environment do not just affect a person's health, they also determine the health of their children and possibly the health of their grandchildren. Non-communicable disease is a global epidemic because of the combined effect of the modern diet (including drug abuse) and a sedentary lifestyle. A low energy dense, drug-free diet rich in bioavailable nutrients-plus-exercise is most effective for preventing non-communicable disease throughout life. Nanoc...

  18. Preventing the Epidemic of Non-Communicable Diseases: An Overview

    OpenAIRE

    2013-01-01

    International audience; Diet, lifestyle and environment do not just affect a person's health, they also determine the health of their children and possibly the health of their grandchildren. Non-communicable disease is a global epidemic because of the combined effect of the modern diet (including drug abuse) and a sedentary lifestyle. A low energy dense, drug-free diet rich in bioavailable nutrients-plus-exercise is most effective for preventing non-communicable disease throughout life. Nanoc...

  19. [Epidemics and diseases during the Independence period in Mexico].

    Science.gov (United States)

    Viesca-Treviño, Carlos

    2010-01-01

    The epidemics and endemic diseases in Mexico were not a problem before the Independence period. Hunger was less than in the past. The 1806 Influenza epidemics had been forgotten. Measles was considered a benign illness. In 1810, there was an increase in the number of cases of black vomit in Veracruz. Sixty percent of 541 hospitalized patients die of the disease. In 1812, an outbreak of yellow fever spread from Veracruz to Jalapa accompanying the movement of troops and killing over 300 soldiers of the Castilla's Battalion. The appearance of petechial fever, maybe typhus marketed in 1813 the onset of the most important epidemics. The preceding was the indirect effect of war: diseases of prisons and military quarters which became overwhelming in times where the movements of troops and of important groups of populations along with crowing, loss homes, hunger and bad hygiene habits. There was also Influenza or "pestilent cold." Measures of detection and quarantine were taken. "Naranjate" mixed with tartaric cremor was used against fever. Fumigation with nitric acid and burners, where they incinerated gun powder were among the health protection policies. It is noteworthy the advance and relief provided by the introduction of smallpox vaccine, the only preventive mean useful against smallpox which was a breakthrough in public health.

  20. On the political economy of plant disease epidemics : capita selecta in historical epidemiology

    NARCIS (Netherlands)

    Zadoks, J.C.

    2008-01-01

    Food security has been and always will be a human concern. Food security has always been fragile, threatened by a variety of factors including plant disease epidemics. Several plant disease epidemics of the past lead to questions like: What happened? How did people deal with these epidemics? What we

  1. Cooperating epidemics of foodborne diseases with diverse trade networks

    CERN Document Server

    Min, Yong; Jin, Xiaogang; Chang, Jie

    2012-01-01

    The frequent outbreak of severe foodborne diseases warns of a potential threat that the global trade networks could spread fatal pathogens. The global trade network is a typical overlay network, which compounds multiple standalone trade networks representing the transmission of a single product and connecting the same set of countries and territories through their own set of trade interactions. Although the epidemic dynamic implications of overlay networks have been debated in recent studies, some general answers for the overlay of multiple and diverse standalone networks remain elusive, especially the relationship between the heterogeneity and diversity of a set of standalone networks and the behavior of the overlay network. In this paper, we establish a general analysis framework for multiple overlay networks based on diversity theory. The framework could reveal the critical epidemic mechanisms beyond overlay processes. Applying the framework to global trade networks, we found that, although the distributio...

  2. Optimal sampling strategies for detecting zoonotic disease epidemics.

    Science.gov (United States)

    Ferguson, Jake M; Langebrake, Jessica B; Cannataro, Vincent L; Garcia, Andres J; Hamman, Elizabeth A; Martcheva, Maia; Osenberg, Craig W

    2014-06-01

    The early detection of disease epidemics reduces the chance of successful introductions into new locales, minimizes the number of infections, and reduces the financial impact. We develop a framework to determine the optimal sampling strategy for disease detection in zoonotic host-vector epidemiological systems when a disease goes from below detectable levels to an epidemic. We find that if the time of disease introduction is known then the optimal sampling strategy can switch abruptly between sampling only from the vector population to sampling only from the host population. We also construct time-independent optimal sampling strategies when conducting periodic sampling that can involve sampling both the host and the vector populations simultaneously. Both time-dependent and -independent solutions can be useful for sampling design, depending on whether the time of introduction of the disease is known or not. We illustrate the approach with West Nile virus, a globally-spreading zoonotic arbovirus. Though our analytical results are based on a linearization of the dynamical systems, the sampling rules appear robust over a wide range of parameter space when compared to nonlinear simulation models. Our results suggest some simple rules that can be used by practitioners when developing surveillance programs. These rules require knowledge of transition rates between epidemiological compartments, which population was initially infected, and of the cost per sample for serological tests.

  3. Retracing micro-epidemics of Chagas disease using epicenter regression.

    Directory of Open Access Journals (Sweden)

    Michael Z Levy

    2011-09-01

    Full Text Available Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1.

  4. Retracing micro-epidemics of Chagas disease using epicenter regression.

    Science.gov (United States)

    Levy, Michael Z; Small, Dylan S; Vilhena, Daril A; Bowman, Natalie M; Kawai, Vivian; Cornejo del Carpio, Juan G; Cordova-Benzaquen, Eleazar; Gilman, Robert H; Bern, Caryn; Plotkin, Joshua B

    2011-09-01

    Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1.

  5. Understanding impacts of climatic extremes on diarrheal disease epidemics: Insights from mechanistic disease propagation models

    Science.gov (United States)

    Jutla, A.; Akanda, A. S.; Colwell, R. R.

    2013-12-01

    An epidemic outbreak of diarrheal diseases (primarily cholera) in Haiti in 2010 is a reminder that our understanding on disease triggers, transmission and spreading mechanisms is incomplete. Cholera can occur in two forms - epidemic (defined as sudden outbreak in a historically disease free region) and endemic (recurrence and persistence of the disease for several consecutive years). Examples of countries with epidemic cholera include Pakistan (2008), Congo (2008), and most recently Haiti (2010). A significant difference between endemic and epidemic regions is the mortality rate, i.e., 1% or lower in an endemic regions versus 3-7% during recent epidemic outbreaks. A fundamentally transformational approach - a warning system with several months prediction lead time - is needed to prevent disease outbreak and minimize its impact on population. Lack of information on spatial and temporal variability of disease incidence as well as transmission in human population continues to be significant challenge in the development of early-warning systems for cholera. Using satellite data on regional hydroclimatic processes, water and sanitation infrastructure indices, and biological pathogen growth information, here we present a Simple, Mechanistic, Adaptive, Remote sensing based Regional Transmission or SMART model to (i) identify regions of potential cholera outbreaks and (ii) quantify mechanism of spread of the disease in previously disease free region. Our results indicate that epidemic regions are located near regional rivers and are characterized by sporadic outbreaks, which are likely to be initiated during episodes of prevailing warm air temperature with low river flows, creating favorable environmental conditions for the growth of cholera bacteria. Heavy rainfall, through inundation or breakdown of sanitary infrastructure, accelerates interaction between contaminated water and human activities, resulting in an epidemic. We discuss the above findings in light of

  6. Cardiovascular disease in Latin America: the growing epidemic.

    Science.gov (United States)

    Fernando, Lanas; Pamela, Serón; Alejandra, Lanas

    2014-01-01

    Cardiovascular diseases (CVD) produce almost a million deaths a year in Latin America (LA), becoming the main cause of death in the last years, and it is estimated that the number of deaths in the region attributable to CVD will increase in the near future. This new epidemic is a consequence of the demographic, economic and social changes observed in LA in recent years. Coronary heart disease and stroke causes 42.5% and 28.8%, respectively of the CVD mortality in the region. Chagas heart involvement and rheumatic heart disease, once a major health problem, are responsible of only 1% of the mortality each. Improving in socioeconomic status, increased life expectancy and high prevalence of risk factors for atherosclerosis have been the major determinants of this marked epidemiologic change.

  7. Early cost-utility analysis of general and cerebrospinal fluid-specific Alzheimer's disease biomarkers for hypothetical disease-modifying treatment decision in mild cognitive impairment

    NARCIS (Netherlands)

    Handels, Ron L. H.; Joore, Manuela A.; Tran-Duy, An; Wimo, Anders; Wolfs, Claire A. G.; Verhey, Frans R. J.; Severens, Johan L.

    2015-01-01

    Introduction: The study aimed to determine the room for improvement of a perfect cerebrospinal fluid (CSF) biomarker and the societal incremental net monetary benefit of CSF in subjects with mild cognitive impairment (MCI) assuming a hypothetical disease-modifying Alzheimer's disease (AD) treatment.

  8. Epidemic progression on networks based on disease generation time

    Science.gov (United States)

    Davoudi, Bahman; Moser, Flavia; Brauer, Fred; Pourbohloul, Babak

    2013-01-01

    We investigate the time evolution of disease spread on a network and present an analytical framework using the concept of disease generation time. Assuming a susceptible–infected–recovered epidemic process, this network-based framework enables us to calculate in detail the number of links (edges) within the network that are capable of producing new infectious nodes (individuals), the number of links that are not transmitting the infection further (non-transmitting links), as well as the number of contacts that individuals have with their neighbours (also known as degree distribution) within each epidemiological class, for each generation period. Using several examples, we demonstrate very good agreement between our analytical calculations and the results of computer simulations. PMID:23889499

  9. Degree of host susceptibility in the initial disease outbreak influences subsequent epidemic spread.

    Science.gov (United States)

    Severns, Paul M; Estep, Laura K; Sackett, Kathryn E; Mundt, Christopher C

    2014-12-01

    Disease epidemics typically begin as an outbreak of a relatively small, spatially explicit population of infected individuals (focus), in which disease prevalence increases and rapidly spreads into the uninfected, at-risk population. Studies of epidemic spread typically address factors influencing disease spread through the at-risk population, but the initial outbreak may strongly influence spread of the subsequent epidemic.We initiated wheat stripe rust Puccinia striiformis f. sp. tritici epidemics to assess the influence of the focus on final disease prevalence when the degree of disease susceptibility differed between the at-risk and focus populations.When the focus/at-risk plantings consisted of partially genetic resistant and susceptible cultivars, final disease prevalence was statistically indistinguishable from epidemics produced by the focus cultivar in monoculture. In these experimental epidemics, disease prevalence was not influenced by the transition into an at-risk population that differed in disease susceptibility. Instead, the focus appeared to exert a dominant influence on the subsequent epidemic.Final disease prevalence was not consistently attributable to either the focus or the at-risk population when focus/at-risk populations were planted in a factorial set-up with a mixture (~28% susceptible and 72% resistant) and susceptible individuals. In these experimental epidemics, spatial heterogeneity in disease susceptibility within the at-risk population appeared to counter the dominant influence of the focus.Cessation of spore production from the focus (through fungicide/glyphosate application) after 1.3 generations of stripe rust spread did not reduce final disease prevalence, indicating that the focus influence on disease spread is established early in the epidemic.Synthesis and applications. Our experiments indicated that outbreak conditions can be highly influential on epidemic spread, even when disease resistance in the at-risk population is

  10. Obesity and kidney disease: Hidden consequences of the epidemic.

    Science.gov (United States)

    Kovesdy, C P; Furth, S; Zoccali, C; World Kidney Day Steering Committee

    2017-03-01

    Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long-term. The incidence of obesity-related glomerulopathy has increased tenfold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle, and health policy measures that makes preventive behaviors an affordable option.

  11. Copper-2 Hypothesis for Causation of the Current Alzheimer's Disease Epidemic Together with Dietary Changes That Enhance the Epidemic.

    Science.gov (United States)

    Brewer, George J

    2017-03-20

    Alzheimer's disease, the most common cause of dementia, is at epidemic proportions (15 to 44% depending on age, of those age 65 to 84) in the U.S. and other developed countries but remains relatively rare in undeveloped countries. Surprisingly, solid historical data reveal the epidemic is a creature of the last century. That is, the disease was also rare in developed countries, until the 20th century. It is disappointing that these historical and demographic facts have been ignored by the Alzheimer's disease scientific community. Disappointing because these facts clearly point at an environmental change in the 20th century in developed countries as a major factor in causing the epidemic. Some scientists have discarded the claimed rarity of the disease in the 19th century as incorrect, saying that Alzheimer's disease is a disease of aging and that the increasing lifespan of people accounts for the current high prevalence of the disease, but this cavalier attitude ignores historical data indicating there were many elderly people in the 19th century who were not getting Alzheimer's disease with any significant frequency. In this review, after documenting that the observed assertions about historical and demographic facts are correct, evidence is amassed that the main environmental culprit causing the Alzheimer's epidemic is ingestion of divalent copper or copper-2. The two sources of copper-2 ingestion are drinking water and multimineral supplement pills containing copper. The increase in copper plumbing use in developed countries parallels the increasing prevalence of Alzheimer's disease. It has been shown that enough copper is leached from copper plumbing in most households to cause Alzheimer's disease, using the Alzheimer's disease animal model studies as a guide to toxic levels. It is relatively easy to avoid or greatly diminish copper-2 ingestion by not using copper containing supplement pills and testing drinking water for copper levels. If the copper in water

  12. Disease Control Implications of India's Changing Multi-Drug Resistant Tuberculosis Epidemic

    OpenAIRE

    Sze-Chuan Suen; Eran Bendavid; Goldhaber-Fiebert, Jeremy D.

    2014-01-01

    BACKGROUND: Multi-drug resistant tuberculosis (MDR TB) is a major health challenge in India that is gaining increasing public attention, but the implications of India's evolving MDR TB epidemic are poorly understood. As India's MDR TB epidemic is transitioning from a treatment-generated to transmission-generated epidemic, we sought to evaluate the potential effectiveness of the following two disease control strategies on reducing the prevalence of MDR TB: a) improving treatment of non-MDR TB;...

  13. [Epidemics and disease during the Revolution Period in Mexico].

    Science.gov (United States)

    Sanfilippo-Borrás, José

    2010-01-01

    The health condition in Mexico was bad around de beginning of the revolutionary period. The movement of troops led the development of epidemics like yellow fever, typhus, smallpox, and influenza that were enhance with natural disasters and hunger in whole country, from cost to cost and in the north big cities like Monterrey, Guadalajara and Saltillo. Doctor Liceaga conducted a well planned campaign against yellow fever eradicating water stagnant deposits in order to combat the vector transmission, the Aedes aegypti, mosquito with satisfactory results. The first smallpox epidemic in the XX Century in Mexico was in 1916. The Mexican physicians used the smallpox vaccine against this epidemic. An American physician named Howard Taylor Ricketts arrived to Mexico for studying the typhus transmission. Accidentally he had been infected and finally, he died from typhus. Definitively, the epidemics predominate along de revolutionary period in Mexico.

  14. Epidemic assistance by the Centers for Disease Control and Prevention: role of the Epidemic Intelligence Service, 1946-2005.

    Science.gov (United States)

    Thacker, Stephen B; Stroup, Donna F; Sencer, David J

    2011-12-01

    Since 1946, the Centers for Disease Control and Prevention has responded to urgent requests from US states, federal agencies, and international organizations through epidemic-assistance investigations (Epi-Aids). The authors describe the first 60 years of Epi-Aids, breadth of problems addressed, evolution of methodologies, scope of activities, and impact of investigations on population health. They reviewed Epi-Aid reports and EIS Bulletins, contacted current and former Epidemic Intelligence Service staff, and systematically searched the PubMed and Web of Science databases. They abstracted information on dates, location, staff involved, health problems, methods, and impacts of investigations according to a preplanned protocol. They assessed the methods presented as well as the quality of reports. During 1946-2005, a total of 4,484 investigations of health events were initiated by 2,815 Epidemic Intelligence Service officers. In the early years, the majority were in response to infectious agents, although environmental problems emerged. Investigations in subsequent years focused on occupational conditions, birth defects, reproductive health, tobacco use, cancer, violence, legal debate, and terrorism. These Epi-Aids heralded expansion of the agency's mission and presented new methods in statistics and epidemiology. Recommendations from Epi-Aids led to policy implementation, evaluation, or modification. Epi-Aids provide the Centers for Disease Control and Prevention with the agility to respond rapidly to public health crises.

  15. Results of epidemic simulation modeling to evaluate strategies to control an outbreak of foot-and-mouth disease.

    Science.gov (United States)

    Bates, Thomas W; Thurmond, Mark C; Carpenter, Tim E

    2003-02-01

    To assess estimated effectiveness of control and eradication procedures for foot-and-mouth disease (FMD) in a region of California. 2,238 herds and 5 sale yards in Fresno, Kings, andTulare counties of California. A spatial stochastic model was used to simulate hypothetical epidemics of FMD for specified control scenarios that included a baseline eradication strategy mandated by USDA and supplemental control strategies of slaughter or vaccination of all animals within a specified distance of infected herds, slaughter of only high-risk animals identified by use of a model simulation, and expansion of infected and surveillance zones. Median number of herds affected varied from 1 to 385 (17% of all herds), depending on type of index herd and delay in diagnosis of FMD. Percentage of herds infected decreased from that of the baseline eradication strategy by expanding the designated infected area from 10 to 20 km (48%), vaccinating within a 50-km radius of an infected herd (41%), slaughtering the 10 highest-risk herds for each infected herd (39%), and slaughtering all animals within 5 km of an infected herd (24%). Results for the model provided a means of assessing the relative merits of potential strategies for control and eradication of FMD should it enter the US livestock population. For the study region, preemptive slaughter of highest-risk herds and vaccination of all animals within a specified distance of an infected herd consistently decreased size and duration of an epidemic, compared with the baseline eradication strategy.

  16. A chaotic model for the epidemic of Ebola virus disease in West Africa (2013-2016).

    Science.gov (United States)

    Mangiarotti, Sylvain; Peyre, Marisa; Huc, Mireille

    2016-11-01

    An epidemic of Ebola Virus Disease (EVD) broke out in Guinea in December 2013. It was only identified in March 2014 while it had already spread out in Liberia and Sierra Leone. The spill over of the disease became uncontrollable and the epidemic could not be stopped before 2016. The time evolution of this epidemic is revisited here with the global modeling technique which was designed to obtain the deterministic models from single time series. A generalized formulation of this technique for multivariate time series is introduced. It is applied to the epidemic of EVD in West Africa focusing on the period between March 2014 and January 2015, that is, before any detected signs of weakening. Data gathered by the World Health Organization, based on the official publications of the Ministries of Health of the three main countries involved in this epidemic, are considered in our analysis. Two observed time series are used: the daily numbers of infections and deaths. A four-dimensional model producing a very complex dynamical behavior is obtained. The model is tested in order to investigate its skills and drawbacks. Our global analysis clearly helps to distinguish three main stages during the epidemic. A characterization of the obtained attractor is also performed. In particular, the topology of the chaotic attractor is analyzed and a skeleton is obtained for its structure.

  17. A chaotic model for the epidemic of Ebola virus disease in West Africa (2013-2016)

    Science.gov (United States)

    Mangiarotti, Sylvain; Peyre, Marisa; Huc, Mireille

    2016-11-01

    An epidemic of Ebola Virus Disease (EVD) broke out in Guinea in December 2013. It was only identified in March 2014 while it had already spread out in Liberia and Sierra Leone. The spill over of the disease became uncontrollable and the epidemic could not be stopped before 2016. The time evolution of this epidemic is revisited here with the global modeling technique which was designed to obtain the deterministic models from single time series. A generalized formulation of this technique for multivariate time series is introduced. It is applied to the epidemic of EVD in West Africa focusing on the period between March 2014 and January 2015, that is, before any detected signs of weakening. Data gathered by the World Health Organization, based on the official publications of the Ministries of Health of the three main countries involved in this epidemic, are considered in our analysis. Two observed time series are used: the daily numbers of infections and deaths. A four-dimensional model producing a very complex dynamical behavior is obtained. The model is tested in order to investigate its skills and drawbacks. Our global analysis clearly helps to distinguish three main stages during the epidemic. A characterization of the obtained attractor is also performed. In particular, the topology of the chaotic attractor is analyzed and a skeleton is obtained for its structure.

  18. Integrating Remote Sensing and Disease Surveillance to Forecast Malaria Epidemics

    Science.gov (United States)

    Wimberly, M. C.; Beyane, B.; DeVos, M.; Liu, Y.; Merkord, C. L.; Mihretie, A.

    2015-12-01

    Advance information about the timing and locations of malaria epidemics can facilitate the targeting of resources for prevention and emergency response. Early detection methods can detect incipient outbreaks by identifying deviations from expected seasonal patterns, whereas early warning approaches typically forecast future malaria risk based on lagged responses to meteorological factors. A critical limiting factor for implementing either of these approaches is the need for timely and consistent acquisition, processing and analysis of both environmental and epidemiological data. To address this need, we have developed EPIDEMIA - an integrated system for surveillance and forecasting of malaria epidemics. The EPIDEMIA system includes a public health interface for uploading and querying weekly surveillance reports as well as algorithms for automatically validating incoming data and updating the epidemiological surveillance database. The newly released EASTWeb 2.0 software application automatically downloads, processes, and summaries remotely-sensed environmental data from multiple earth science data archives. EASTWeb was implemented as a component of the EPIDEMIA system, which combines the environmental monitoring data and epidemiological surveillance data into a unified database that supports both early detection and early warning models. Dynamic linear models implemented with Kalman filtering were used to carry out forecasting and model updating. Preliminary forecasts have been disseminated to public health partners in the Amhara Region of Ethiopia and will be validated and refined as the EPIDEMIA system ingests new data. In addition to continued model development and testing, future work will involve updating the public health interface to provide a broader suite of outbreak alerts and data visualization tools that are useful to our public health partners. The EPIDEMIA system demonstrates a feasible approach to synthesizing the information from epidemiological

  19. Phylogeographic analysis of the 2000-2002 foot-and-mouth disease epidemic in Argentina

    Science.gov (United States)

    Foot-and-mouth disease (FMD) is a highly transmissible disease of livestock. FMD has been eradicated from many countries and the consequences of FMD epidemics are, in some cases, devastating. That was the case of Argentina in 2000-2002, where within few months, FMD virus spread throughout most of t...

  20. AIDS Epidemic Spurs Social Scientists to Examine Behavior Linked to Disease.

    Science.gov (United States)

    Wheeler, David L.

    1987-01-01

    The AIDS epidemic is spurring social scientists to try to understand the social and sexual forces that spread the sexually transmitted disease, to learn how to change the personal behavior that makes up those forces, and to improve and prolong the lives of those who have the disease. (MLW)

  1. Protection motivation theory and social distancing behaviour in response to a simulated infectious disease epidemic.

    Science.gov (United States)

    Williams, Lynn; Rasmussen, Susan; Kleczkowski, Adam; Maharaj, Savi; Cairns, Nicole

    2015-01-01

    Epidemics of respiratory infectious disease remain one of the most serious health risks facing the population. Non-pharmaceutical interventions (e.g. hand-washing or wearing face masks) can have a significant impact on the course of an infectious disease epidemic. The current study investigated whether protection motivation theory (PMT) is a useful framework for understanding social distancing behaviour (i.e. the tendency to reduce social contacts) in response to a simulated infectious disease epidemic. There were 230 participants (109 males, 121 females, mean age 32.4 years) from the general population who completed self-report measures assessing the components of PMT. In addition, participants completed a computer game which simulated an infectious disease epidemic in order to provide a measure of social distancing behaviour. The regression analyses revealed that none of the PMT variables were significant predictors of social distancing behaviour during the simulation task. However, fear (β = .218, p < .001), response efficacy (β = .175, p < .01) and self-efficacy (β = .251, p < .001) were all significant predictors of intention to engage in social distancing behaviour. Overall, the PMT variables (and demographic factors) explain 21.2% of the variance in intention. The findings demonstrated that PMT was a useful framework for understanding intention to engage in social distancing behaviour, but not actual behaviour during the simulated epidemic. These findings may reflect an intention-behaviour gap in relation to social distancing behaviour.

  2. The Dynamics of Epidemic Model with Two Types of Infectious Diseases and Vertical Transmission

    Directory of Open Access Journals (Sweden)

    Raid Kamel Naji

    2016-01-01

    Full Text Available An epidemic model that describes the dynamics of the spread of infectious diseases is proposed. Two different types of infectious diseases that spread through both horizontal and vertical transmission in the host population are considered. The basic reproduction number R0 is determined. The local and the global stability of all possible equilibrium points are achieved. The local bifurcation analysis and Hopf bifurcation analysis for the four-dimensional epidemic model are studied. Numerical simulations are used to confirm our obtained analytical results.

  3. Predictability and epidemic pathways in global outbreaks of infectious diseases: the SARS case study

    Directory of Open Access Journals (Sweden)

    Barthélemy Marc

    2007-11-01

    Full Text Available Abstract Background The global spread of the severe acute respiratory syndrome (SARS epidemic has clearly shown the importance of considering the long-range transportation networks in the understanding of emerging diseases outbreaks. The introduction of extensive transportation data sets is therefore an important step in order to develop epidemic models endowed with realism. Methods We develop a general stochastic meta-population model that incorporates actual travel and census data among 3 100 urban areas in 220 countries. The model allows probabilistic predictions on the likelihood of country outbreaks and their magnitude. The level of predictability offered by the model can be quantitatively analyzed and related to the appearance of robust epidemic pathways that represent the most probable routes for the spread of the disease. Results In order to assess the predictive power of the model, the case study of the global spread of SARS is considered. The disease parameter values and initial conditions used in the model are evaluated from empirical data for Hong Kong. The outbreak likelihood for specific countries is evaluated along with the emerging epidemic pathways. Simulation results are in agreement with the empirical data of the SARS worldwide epidemic. Conclusion The presented computational approach shows that the integration of long-range mobility and demographic data provides epidemic models with a predictive power that can be consistently tested and theoretically motivated. This computational strategy can be therefore considered as a general tool in the analysis and forecast of the global spreading of emerging diseases and in the definition of containment policies aimed at reducing the effects of potentially catastrophic outbreaks.

  4. Behavioral responses to epidemics in an online experiment: using virtual diseases to study human behavior.

    Science.gov (United States)

    Chen, Frederick; Griffith, Amanda; Cottrell, Allin; Wong, Yue-Ling

    2013-01-01

    We report the results of a study we conducted using a simple multiplayer online game that simulates the spread of an infectious disease through a population composed of the players. We use our virtual epidemics game to examine how people respond to epidemics. The analysis shows that people's behavior is responsive to the cost of self-protection, the reported prevalence of disease, and their experiences earlier in the epidemic. Specifically, decreasing the cost of self-protection increases the rate of safe behavior. Higher reported prevalence also raises the likelihood that individuals would engage in self-protection, where the magnitude of this effect depends on how much time has elapsed in the epidemic. Individuals' experiences in terms of how often an infection was acquired when they did not engage in self-protection are another factor that determines whether they will invest in preventive measures later on. All else being equal, individuals who were infected at a higher rate are more likely to engage in self-protective behavior compared to those with a lower rate of infection. Lastly, fixing everything else, people's willingness to engage in safe behavior waxes or wanes over time, depending on the severity of an epidemic: when prevalence is high, people are more likely to adopt self-protective measures as time goes by; when prevalence is low, a 'self-protection fatigue' effect sets in whereby individuals are less willing to engage in safe behavior over time.

  5. Mexico's other wars: epidemics, disease, and public health in Guanajuato, Mexico, 1810-1867.

    Science.gov (United States)

    Thompson, A T

    1996-01-01

    "Mexico's Other Wars" refers to the fight against disease, particularly epidemic disease, during the period when Mexico gained its independence and was involved in the very conflictive process of nation-building, from 1810-1867. Controlling and eradicating disease was an integral part of that process. In this period, fighting disease assumed the crucial political purpose of making all people healthier as one means of building an economically productive civil society. To attain this goal, early nineteenth-century local policy makers organized an increasingly secular and integrated public health system governed by municipal and state officials who legislated local public health regulations. While disease was not eradicated, the incidence and severity of epidemics decreased and likely contributed, as one of many factors, to population increase. This process was evident in the city and state of Guanajuato, the focus of this paper, for Guanajuato's population almost doubled in this period despite war and intermittent armed conflict.

  6. Topographic determinants of foot and mouth disease transmission in the UK 2001 epidemic

    Directory of Open Access Journals (Sweden)

    Keeling Matthew J

    2006-01-01

    Full Text Available Abstract Background A key challenge for modelling infectious disease dynamics is to understand the spatial spread of infection in real landscapes. This ideally requires a parallel record of spatial epidemic spread and a detailed map of susceptible host density along with relevant transport links and geographical features. Results Here we analyse the most detailed such data to date arising from the UK 2001 foot and mouth epidemic. We show that Euclidean distance between infectious and susceptible premises is a better predictor of transmission risk than shortest and quickest routes via road, except where major geographical features intervene. Conclusion Thus, a simple spatial transmission kernel based on Euclidean distance suffices in most regions, probably reflecting the multiplicity of transmission routes during the epidemic.

  7. Ebola virus disease in West Africa: outbreak or epidemic?

    African Journals Online (AJOL)

    Gboyega Ogunbanjo

    2014-08-20

    Aug 20, 2014 ... By definition, a disease “outbreak” is “the occurrence of cases of disease in a ... waiting for things to go wrong, and then expecting others to solve the problem for us? ... WHO [homepage on the Internet]. c2014. Available from: ...

  8. The epidemic of the 20(th) century: coronary heart disease.

    Science.gov (United States)

    Dalen, James E; Alpert, Joseph S; Goldberg, Robert J; Weinstein, Ronald S

    2014-09-01

    Heart disease was an uncommon cause of death in the US at the beginning of the 20th century. By mid-century it had become the commonest cause. After peaking in the mid-1960s, the number of heart disease deaths began a marked decline that has persisted to the present. The increase in heart disease deaths from the early 20th century until the 1960s was due to an increase in the prevalence of coronary atherosclerosis with resultant coronary heart disease, as documented by autopsy studies. This increase was associated with an increase in smoking and dietary changes leading to an increase in serum cholesterol levels. In addition, the ability to diagnose acute myocardial infarction with the aid of the electrocardiogram increased the recognition of coronary heart disease before death. The substantial decrease in coronary heart disease deaths after the mid-1960s is best explained by the decreased incidence, and case fatality rate, of acute myocardial infarction and a decrease in out-of-hospital sudden coronary heart disease deaths. These decreases are very likely explained by a decrease in coronary atherosclerosis due to primary prevention, and a decrease in the progression of nonobstructive coronary atherosclerosis to obstructive coronary heart disease due to efforts of primary and secondary prevention. In addition, more effective treatment of patients hospitalized with acute myocardial infarction has led to a substantial decrease in deaths due to acute myocardial infarction. It is very likely that the 20th century was the only century in which heart disease was the most common cause of death in America.

  9. Obesity and lower limb venous disease - The epidemic of phlebesity.

    Science.gov (United States)

    Davies, Huw Ob; Popplewell, Matthew; Singhal, Rishi; Smith, Neil; Bradbury, Andrew W

    2017-05-01

    Introduction Lower limb venous disease affects up to one half, and obesity up to one quarter, of the adult population. Many people are therefore affected by, and present to health services for the treatment of both conditions. This article reviews the available evidence of pathophysiological and clinical relationship between obesity and varicose veins, chronic venous insufficiency and ulceration and deep vein thrombosis. Methods A literature search of PubMed and Cochrane libraries was performed in accordance with PRISMA statement from 1946 to 2015, with further article identification from following cited references for articles examining the relationship between obesity and venous disease. Search terms included obesity, overweight, thrombosis, varicose veins, CEAP, chronic venous insufficiency, treatment, endovenous, endothermal, sclerotherapy, bariatric surgery and deep vein thrombosis. Results The proportion of the population suffering from lower limb venous disease and obesity is increasing. Obesity is an important risk factor for all types of lower limb venous disease, and obese patients with lower limb venous disease are more likely to be symptomatic as a result of their lower limb venous disease. The clinical diagnosis, investigation, imaging and treatment of lower limb venous disease in obese people present a number of challenges. The evidence base underpinning medical, surgical and endovenous management of lower limb venous disease in obese people is limited and such treatment may be associated with worse outcomes and increased risks when compared to patients with a normal body mass index. Conclusion Lower limb venous disease and obesity are both increasingly common. As such, phlebologists will be treating ever greater numbers of obese patients with lower limb venous disease, and clinicians in many other specialties are going to be treating a wide range of obesity-related health problems in people with or at risk of lower limb venous disease. Unfortunately

  10. Communicating risk and promoting disease mitigation measures in epidemics and emerging disease settings.

    Science.gov (United States)

    Schiavo, Renata; May Leung, May; Brown, Mason

    2014-03-01

    This review aims to identify and assess evidence on interventions to communicate risk and promote disease mitigation measures in epidemics and emerging disease outbreak settings. The study focuses on data that are relevant to low and middle-income country (LMIC) settings. We conducted a comprehensive literature search using five major electronic databases (Pubmed Medline, Biomed Central, EMBASE, Science of Citation Index, and Cochrane Library) and other sources to identify relevant studies published from January 2002 to July 2013. The review was guided by the socio-ecological model/perspective of public health and the ideation theory and focused on interventions at the community, healthcare, and multi-sectoral settings, which also reflect key intervention levels of the Ottawa Charter for Health Promotion. Eligible quantitative studies were selected according to specific study criteria and assessed using the Critical Appraisal Skills Program (CASP) framework. Conversely, qualitative studies, reviews, case studies, and editorials were not included. Studies were selected by two independent reviewers. Twenty-nine relevant studies from 16 countries were included. Most studies focused on a single intervention or intervention level, rather than multi-sectoral interventions. The majority of the evidence relates to programs aimed at behavioral and social results (or relevant intermediate steps) within a specific population group. Two studies included implications for improvements in health service delivery, two studies examined the intervention's impact on health systems-related outcomes, and three had also implications for environmental health outcomes. Cost- and health equity-related implications for select evidence were also discussed. The paucity of well-designed quantitative evaluations of interventions to communicate health risk and promote disease control measures in LMICs does not allow for any definitive conclusions. Yet, the review identified several promising

  11. The link between the epidemics of obesity and allergic diseases

    DEFF Research Database (Denmark)

    Hersoug, Lars-Georg; Linneberg, A

    2007-01-01

    There is increasing epidemiological evidence that obesity increases the risk of asthma, atopic, and autoimmune diseases. We hypothesize that the increase in these diseases is caused, at least in part, by decreased immunological tolerance as a consequence of immunological changes induced by adipok......There is increasing epidemiological evidence that obesity increases the risk of asthma, atopic, and autoimmune diseases. We hypothesize that the increase in these diseases is caused, at least in part, by decreased immunological tolerance as a consequence of immunological changes induced......-lymphocytes (Tregs). Additionally, adiponectin, which decreases with increasing obesity, down-regulates the secretion of IL10 from macrophages and adipocytes. These changes in IL6, leptin, and IL10 decrease the regulatory effect of Tregs resulting in decreased immunological tolerance to antigens. In pregnant women......, these obesity-induced immunological changes might be transmitted to the fetus by epigenetic inheritance thereby increasing the risk of atopic disease. We propose that obesity results in immunological changes resulting in decreased immunological tolerance to antigens and skewing of the immune system towards a Th...

  12. [Epidemic diseases in the Polish Kingdom in the thirties of the 19th century].

    Science.gov (United States)

    Rutkowski, Marek

    2004-01-01

    We can observe that after downfall of the November Insurrection the authorities of the Polish Kingdom were effectively engaged in the fight against numerous epidemic diseases plaguing the local society. Among "contagions" of the time there were varicella, "gastric-nervous fever", "gastric-rhinitis fever" and typhus (especially in 1836). As usual, cholera was the most dangerous one. All medical and epidemiological services in the Polish Kingdom were making effective remedial measures in order to neutralize results of the epidemics. The implemented methods were effective enough to limit considerably the incidence and number of deceased during the epidemic, which started in October 1836 and lasted till the next year. An obligation of effective cooperation between the Polish authorities and the Russian army was introduced then. The sanitary action against cholera in 1836-1837 should be very highly assessed from the logistic point of view. The wide action of protective vaccination against varicella and numerous sanitary rules completed the favorable image of the Polish Kingdom sanitary services. All the factors mentioned above lead to a conclusion that in the thirtieth of the 19th century both civil and military authorities of the Polish Kingdom did practically utmost in order to limit negative results of cyclical recurrences of epidemic diseases. It should be also stressed that the protective actions undertaken in that time were both direct and long lasting enterprises.

  13. Political Economy of Epidemic Kidney Disease in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Asoka Bandarage

    2013-10-01

    Full Text Available The Chronic Kidney Disease (CKD, taking the lives of thousands in poor farming communities in Sri Lanka, is commonly seen as a problem peculiar to the island’s north central dry zone agricultural region. The prevailing bio-medical focus is on identifying one or more “environmental nephrotoxins.” While delineating important controversies on the etiology of the disease, this article seeks to broaden the discourse on the hitherto neglected political economy of CKD in Sri Lanka. In so doing, it seeks to bring together the bio-medical debate on the impact of widespread and unregulated use of agrochemicals on public health and kidney disease with broader global interdisciplinary perspectives on the industrialization of agriculture and the consolidation of food production by transnational agribusiness corporations. The article concludes pointing out environmentally sustainable and socially equitable development and organic agriculture as the long-term solutions to CKD in Sri Lanka and elsewhere.

  14. Mortality from diabetic renal disease: a hidden epidemic.

    Science.gov (United States)

    Rao, Chalapati; Adair, Timothy; Bain, Chris; Doi, Suhail A R

    2012-04-01

    Population-level mortality indicators can be useful outcome measures of diabetes care. Death registration systems serve as the main source of data for such measures. However, standard mortality indicators based on underlying causes do not adequately reflect the burden from diabetic renal disease. This article presents findings from analysis of multiple causes of death available from death registration data for Australia and USA. Both countries use an automated system that applies prescribed rules to select and code the underlying cause for each registered death. Deaths with diabetes as underlying cause were grouped according to their diabetic complications as defined by the International Classification of Diseases. Age-standardized mortality rates were calculated for the underlying cause rubric 'diabetes with renal complications'. These were contrasted with rates calculated using additional deaths where diabetes was the underlying cause and renal failure was listed as a consequence. These analyses identified that current automated programmes code three-fourths of all diabetes deaths to 'diabetes without complications', despite additional factors being listed. Estimated multiple cause death rates from diabetic renal disease are four to nine times higher than underlying cause rates for 'diabetes with renal complications' in both countries; and show a rising trend in contrast to the latter. These findings indicate that routine underlying cause statistics for USA and Australia grossly under estimate mortality from diabetic renal disease. Clear guidelines on the certification, coding and statistical presentation of diabetes mortality are needed for epidemiology and health policy.

  15. The Silent Epidemic. Teens and Sexually Transmitted Diseases.

    Science.gov (United States)

    Francis, Susan

    1998-01-01

    One-quarter of the 3 million new cases of sexually transmitted diseases (STDs) each year occur in teenagers. Teens are at high risk because of biological, age, and behavioral factors. Education is the best weapon against STDs. As their children's first sex educators, parents must make every effort to promote STD education at home and school. (SM)

  16. Obesity and kidney disease: hidden consequences of the epidemic

    African Journals Online (AJOL)

    exercise, can dramatically help in preventing obesity and kidney disease. ... Epidemiology of obesity in adults and children. Over the last 3 ... of obesity also affects children. In the US in .... population-based study of 5.24 million individuals from the UK, .... intervention including caloric restriction and increased physical activity ...

  17. Detection of Severe Respiratory Disease Epidemic Outbreaks by CUSUM-Based Overcrowd-Severe-Respiratory-Disease-Index Model

    Directory of Open Access Journals (Sweden)

    Carlos Polanco

    2013-01-01

    Full Text Available A severe respiratory disease epidemic outbreak correlates with a high demand of specific supplies and specialized personnel to hold it back in a wide region or set of regions; these supplies would be beds, storage areas, hemodynamic monitors, and mechanical ventilators, as well as physicians, respiratory technicians, and specialized nurses. We describe an online cumulative sum based model named Overcrowd-Severe-Respiratory-Disease-Index based on the Modified Overcrowd Index that simultaneously monitors and informs the demand of those supplies and personnel in a healthcare network generating early warnings of severe respiratory disease epidemic outbreaks through the interpretation of such variables. A post hoc historical archive is generated, helping physicians in charge to improve the transit and future allocation of supplies in the entire hospital network during the outbreak. The model was thoroughly verified in a virtual scenario, generating multiple epidemic outbreaks in a 6-year span for a 13-hospital network. When it was superimposed over the H1N1 influenza outbreak census (2008–2010 taken by the National Institute of Medical Sciences and Nutrition Salvador Zubiran in Mexico City, it showed that it is an effective algorithm to notify early warnings of severe respiratory disease epidemic outbreaks with a minimal rate of false alerts.

  18. Detection of severe respiratory disease epidemic outbreaks by CUSUM-based overcrowd-severe-respiratory-disease-index model.

    Science.gov (United States)

    Polanco, Carlos; Castañón-González, Jorge Alberto; Macías, Alejandro E; Samaniego, José Lino; Buhse, Thomas; Villanueva-Martínez, Sebastián

    2013-01-01

    A severe respiratory disease epidemic outbreak correlates with a high demand of specific supplies and specialized personnel to hold it back in a wide region or set of regions; these supplies would be beds, storage areas, hemodynamic monitors, and mechanical ventilators, as well as physicians, respiratory technicians, and specialized nurses. We describe an online cumulative sum based model named Overcrowd-Severe-Respiratory-Disease-Index based on the Modified Overcrowd Index that simultaneously monitors and informs the demand of those supplies and personnel in a healthcare network generating early warnings of severe respiratory disease epidemic outbreaks through the interpretation of such variables. A post hoc historical archive is generated, helping physicians in charge to improve the transit and future allocation of supplies in the entire hospital network during the outbreak. The model was thoroughly verified in a virtual scenario, generating multiple epidemic outbreaks in a 6-year span for a 13-hospital network. When it was superimposed over the H1N1 influenza outbreak census (2008-2010) taken by the National Institute of Medical Sciences and Nutrition Salvador Zubiran in Mexico City, it showed that it is an effective algorithm to notify early warnings of severe respiratory disease epidemic outbreaks with a minimal rate of false alerts.

  19. Harvesting can increase severity of wildlife disease epidemics

    OpenAIRE

    Choisy, Marc; Rohani, Pejman

    2006-01-01

    Theoretical studies of wildlife population dynamics have proved insightful for sustainable management, where the principal aim is to maximize short-term yield, without risking population extinction. Surprisingly, infectious diseases have not been accounted for in harvest models, which is a major oversight because the consequences of parasites for host population dynamics are well-established. Here, we present a simple general model for a host species subject to density dependent reproduction ...

  20. Some Models for Epidemics of Vector-Transmitted Diseases

    OpenAIRE

    Brauer, Fred; Castillo-Chavez, Carlos; Mubayi, Anuj; Towers, Sherry

    2016-01-01

    Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito) vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birt...

  1. Population-level differences in disease transmission: a Bayesian analysis of multiple smallpox epidemics.

    Science.gov (United States)

    Elderd, Bret D; Dwyer, Greg; Dukic, Vanja

    2013-09-01

    Estimates of a disease's basic reproductive rate R0 play a central role in understanding outbreaks and planning intervention strategies. In many calculations of R0, a simplifying assumption is that different host populations have effectively identical transmission rates. This assumption can lead to an underestimate of the overall uncertainty associated with R0, which, due to the non-linearity of epidemic processes, may result in a mis-estimate of epidemic intensity and miscalculated expenditures associated with public-health interventions. In this paper, we utilize a Bayesian method for quantifying the overall uncertainty arising from differences in population-specific basic reproductive rates. Using this method, we fit spatial and non-spatial susceptible-exposed-infected-recovered (SEIR) models to a series of 13 smallpox outbreaks. Five outbreaks occurred in populations that had been previously exposed to smallpox, while the remaining eight occurred in Native-American populations that were naïve to the disease at the time. The Native-American outbreaks were close in a spatial and temporal sense. Using Bayesian Information Criterion (BIC), we show that the best model includes population-specific R0 values. These differences in R0 values may, in part, be due to differences in genetic background, social structure, or food and water availability. As a result of these inter-population differences, the overall uncertainty associated with the "population average" value of smallpox R0 is larger, a finding that can have important consequences for controlling epidemics. In general, Bayesian hierarchical models are able to properly account for the uncertainty associated with multiple epidemics, provide a clearer understanding of variability in epidemic dynamics, and yield a better assessment of the range of potential risks and consequences that decision makers face.

  2. Widespread amphibian extinctions from epidemic disease driven by global warming.

    Science.gov (United States)

    Pounds, J Alan; Bustamante, Martín R; Coloma, Luis A; Consuegra, Jamie A; Fogden, Michael P L; Foster, Pru N; La Marca, Enrique; Masters, Karen L; Merino-Viteri, Andrés; Puschendorf, Robert; Ron, Santiago R; Sánchez-Azofeifa, G Arturo; Still, Christopher J; Young, Bruce E

    2006-01-12

    As the Earth warms, many species are likely to disappear, often because of changing disease dynamics. Here we show that a recent mass extinction associated with pathogen outbreaks is tied to global warming. Seventeen years ago, in the mountains of Costa Rica, the Monteverde harlequin frog (Atelopus sp.) vanished along with the golden toad (Bufo periglenes). An estimated 67% of the 110 or so species of Atelopus, which are endemic to the American tropics, have met the same fate, and a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) is implicated. Analysing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with 'very high confidence' (> 99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances. We propose that temperatures at many highland localities are shifting towards the growth optimum of Batrachochytrium, thus encouraging outbreaks. With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable.

  3. Washing our hands of the congenital cytomegalovirus disease epidemic

    Directory of Open Access Journals (Sweden)

    Cannon Michael J

    2005-06-01

    Full Text Available Abstract Background Each year in the United States, an estimated 40,000 children are born with congenital cytomegalovirus (CMV infection, causing an estimated 400 deaths and leaving approximately 8000 children with permanent disabilities such as hearing or vision loss, or mental retardation. More children are affected by serious CMV-related disabilities than by several better-known childhood maladies, including Down syndrome, fetal alcohol syndrome, and spina bifida. Discussion Congenital CMV is a prime target for prevention not only because of its substantial disease burden but also because the biology and epidemiology of CMV suggest that there are ways to reduce viral transmission. Because exposure to the saliva or urine of young children is a major cause of CMV infection among pregnant women, it is likely that good personal hygiene, especially hand-washing, can reduce the risk of CMV acquisition. Experts agree that such measures are likely to be efficacious (i.e., they will work if consistently followed and the American College of Obstetricians and Gynecologists recommends that physicians counsel pregnant women about preventing CMV acquisition through careful attention to hygiene. However, because of concerns about effectiveness (i.e., Will women consistently follow hygienic practices as the result of interventions?, the medical and public health communities appear reluctant to embrace primary CMV prevention via improved hygienic practices, and educational interventions are rare. Current data on the effectiveness of such measures in preventing CMV infection are promising, but limited. There is strong evidence, however, that educational interventions can prevent other infectious diseases with similar transmission modes, suggesting that effective interventions can also be found for CMV. Until a CMV vaccine becomes available, effective educational interventions are needed to inform women about congenital CMV prevention. Summary Perhaps no single

  4. Disease epidemics: Lessons for resilience in an increasingly connected world

    Science.gov (United States)

    Allen, Craig R.; DeWitte, S.N.; Kurth, M.H.; Linkov, I.

    2016-01-01

    In public health, the term resilience often refers to the personality traits that individuals possess which help them endure and recover from stressors. However, resilience as a system characteristic, especially in regards to complex social-ecological systems, can be informative for public health at scales larger than the individual. Acute shocks to systems occur against a background of existing conditions, which are crucial determinants of the eventual public health outcomes of those shocks, and in the context of complex dependencies among and between ecological and societal elements. Many components of a system's baseline condition are chronic public health concerns themselves and diminish the capacity of the system to perform in the face of acute shocks. The emerging field of resilience management is concerned with holistically assessing and improving a system's ability to prepare for and absorb disruption, and then recover and adapt across physical, information, environmental and social domains. Integrating resilience considerations into current risk- and evidence-based approaches to disease control and prevention1 can move public health efforts toward more proactive and comprehensive solutions for protecting and improving the health of communities. Here, we look to the case of the Black Death as an illustrative case of a dramatic transformation in human history, an acute shock to a system that was underlain by chronic social maladies, to derive lessons about resilience management for public health in contemporary systems.

  5. Alzheimer Disease and Its Growing Epidemic: Risk Factors, Biomarkers, and the Urgent Need for Therapeutics.

    Science.gov (United States)

    Hickman, Richard A; Faustin, Arline; Wisniewski, Thomas

    2016-11-01

    Alzheimer disease (AD) represents one of the greatest medical challenges of this century; the condition is becoming increasingly prevalent worldwide and no effective treatments have been developed for this terminal disease. Because the disease manifests at a late stage after a long period of clinically silent neurodegeneration, knowledge of the modifiable risk factors and the implementation of biomarkers is crucial in the primary prevention of the disease and presymptomatic detection of AD, respectively. This article discusses the growing epidemic of AD and antecedent risk factors in the disease process. Disease biomarkers are discussed, and the implications that this may have for the treatment of this currently incurable disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Epidemic disease decimates amphibian abundance, species diversity, and evolutionary history in the highlands of central Panama.

    Science.gov (United States)

    Crawford, Andrew J; Lips, Karen R; Bermingham, Eldredge

    2010-08-01

    Amphibian populations around the world are experiencing unprecedented declines attributed to a chytrid fungal pathogen, Batrachochytrium dendrobatidis. Despite the severity of the crisis, quantitative analyses of the effects of the epidemic on amphibian abundance and diversity have been unavailable as a result of the lack of equivalent data collected before and following disease outbreak. We present a community-level assessment combining long-term field surveys and DNA barcode data describing changes in abundance and evolutionary diversity within the amphibian community of El Copé, Panama, following a disease epidemic and mass-mortality event. The epidemic reduced taxonomic, lineage, and phylogenetic diversity similarly. We discovered that 30 species were lost, including five undescribed species, representing 41% of total amphibian lineage diversity in El Copé. These extirpations represented 33% of the evolutionary history of amphibians within the community, and variation in the degree of population loss and decline among species was random with respect to the community phylogeny. Our approach provides a fast, economical, and informative analysis of loss in a community whether measured by species or phylogenetic diversity.

  7. [Differences in influenza epidemics in Osaka City--epidemiological surveillance of infectious disease].

    Science.gov (United States)

    Murakami, T; Haruki, K; Seto, Y; Kimura, T; Shibe, K; Minoshiro, S

    1994-05-01

    Influenza viruses in outpatients with influenza symptoms in Osaka City were analyzed in an epidemiological surveillance of infectious disease between 1989 and 1993. During influenza epidemics a mixed prevalence of several types of influenza viruses existed. Three types of influenza viruses, AH1, AH3 and B, were isolated during the 1990/1991 season. Remarkably the three types of viruses were discovered in samplings collected on the same day and within a narrow area inside a radius of 800-1,000m from the surveyed hospitals. Different types of viruses were detected between brothers and among school children from same housing complexes. Influenza AH3 viruses detected in 1992/1993 season differed in antigenicity from those detected in the 1990/1991 and 1991/1992 seasons. Therefore it appears that mutation of the AH3 virus contributed to the large-scale influenza epidemic which occurred in the 1992/1993 season.

  8. Disease prevention versus data privacy: using landcover maps to inform spatial epidemic models.

    Science.gov (United States)

    Tildesley, Michael J; Ryan, Sadie J

    2012-01-01

    The availability of epidemiological data in the early stages of an outbreak of an infectious disease is vital for modelers to make accurate predictions regarding the likely spread of disease and preferred intervention strategies. However, in some countries, the necessary demographic data are only available at an aggregate scale. We investigated the ability of models of livestock infectious diseases to predict epidemic spread and obtain optimal control policies in the event of imperfect, aggregated data. Taking a geographic information approach, we used land cover data to predict UK farm locations and investigated the influence of using these synthetic location data sets upon epidemiological predictions in the event of an outbreak of foot-and-mouth disease. When broadly classified land cover data were used to create synthetic farm locations, model predictions deviated significantly from those simulated on true data. However, when more resolved subclass land use data were used, moderate to highly accurate predictions of epidemic size, duration and optimal vaccination and ring culling strategies were obtained. This suggests that a geographic information approach may be useful where individual farm-level data are not available, to allow predictive analyses to be carried out regarding the likely spread of disease. This method can also be used for contingency planning in collaboration with policy makers to determine preferred control strategies in the event of a future outbreak of infectious disease in livestock.

  9. Disease prevention versus data privacy: using landcover maps to inform spatial epidemic models.

    Directory of Open Access Journals (Sweden)

    Michael J Tildesley

    Full Text Available The availability of epidemiological data in the early stages of an outbreak of an infectious disease is vital for modelers to make accurate predictions regarding the likely spread of disease and preferred intervention strategies. However, in some countries, the necessary demographic data are only available at an aggregate scale. We investigated the ability of models of livestock infectious diseases to predict epidemic spread and obtain optimal control policies in the event of imperfect, aggregated data. Taking a geographic information approach, we used land cover data to predict UK farm locations and investigated the influence of using these synthetic location data sets upon epidemiological predictions in the event of an outbreak of foot-and-mouth disease. When broadly classified land cover data were used to create synthetic farm locations, model predictions deviated significantly from those simulated on true data. However, when more resolved subclass land use data were used, moderate to highly accurate predictions of epidemic size, duration and optimal vaccination and ring culling strategies were obtained. This suggests that a geographic information approach may be useful where individual farm-level data are not available, to allow predictive analyses to be carried out regarding the likely spread of disease. This method can also be used for contingency planning in collaboration with policy makers to determine preferred control strategies in the event of a future outbreak of infectious disease in livestock.

  10. Spatial statistical analysis of basal stem root disease under natural field epidemic of oil palm

    Science.gov (United States)

    Kamu, Assis; Phin, Chong Khim; Seman, Idris Abu; Wan, Hoong Hak; Mun, Ho Chong

    2015-02-01

    Oil palm or scientifically known as Elaeis guineensis Jacq. is the most important commodity crop in Malaysia and has greatly contributed to the economy growth of the country. As far as disease is concerned in the industry, Basal Stem Rot (BSR) caused by Ganoderma boninence remains the most important disease. BSR disease is the most widely studied with information available for oil palm disease in Malaysia. However, there is still limited study on the spatial as well as temporal pattern or distribution of the disease especially under natural field epidemic condition in oil palm plantation. The objective of this study is to spatially identify the pattern of BSR disease under natural field epidemic using two geospatial analytical techniques, which are quadrat analysis for the first order properties of partial pattern analysis and nearest-neighbor analysis (NNA) for the second order properties of partial pattern analysis. Two study sites were selected with different age of tree. Both sites are located in Tawau, Sabah and managed by the same company. The results showed that at least one of the point pattern analysis used which is NNA (i.e. the second order properties of partial pattern analysis) has confirmed the disease is complete spatial randomness. This suggests the spread of the disease is not from tree to tree and the age of palm does not play a significance role in determining the spatial pattern of the disease. From the spatial pattern of the disease, it would help in the disease management program and for the industry in the future. The statistical modelling is expected to help in identifying the right model to estimate the yield loss of oil palm due to BSR disease in the future.

  11. Viral meningitis epidemics and a single, recent, recombinant and anthroponotic origin of swine vesicular disease virus

    DEFF Research Database (Denmark)

    Bruhn, Christian Anders Wathne; Nielsen, Sandra Cathrine Abel; Samaniego Castruita, Jose Alfredo;

    2015-01-01

    BACKGROUND AND OBJECTIVES: Swine vesicular disease virus (SVDV) is a close relative of the human Enterovirus B serotype, coxsackievirus B5. As the etiological agent of a significant emergent veterinary disease, several studies have attempted to explain its origin. However, several key questions r...... stating that SVDV originated through co-infection, recombination, and a single anthroponotic event, during large viral meningitis epidemics around 1960/1961 involving the ancestral serotypes. The exact geographical origin of SVDV may remain untestable due to historical aspects....

  12. Fighting disease and epidemics: Ricardo Jorge and the internationalization of Portuguese science.

    Science.gov (United States)

    de Almeida, Maria Antónia Pires

    2013-06-01

    Ricardo Jorge was one of the principal doctors responsible for the sanitary transition in Portugal. He created and enforced the most important policies for disease control, both endemic and epidemic, which scourged the western world between the mid nineteenth century and beginning of the twentieth. His professional training and academic and scientific performances reveal Ricardo Jorge's value in Portuguese science and his efforts for its internationalization. His capacities were confirmed by the emergency of the sanitary situations with which he was confronted and by the authorities' confidence in him, by putting him in charge of the bubonic plague elimination process.

  13. Global dynamics behaviors for new delay SEIR epidemic disease model with vertical transmission and pulse vaccination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A robust SEIR epidemic disease model with a profitless delay and vertical transmission is formulated, and the dynamics behaviors of the model under pulse vaccination are analyzed.By use of the discrete dynamical system determined by the the model are under appropriate conditions.Using the theory on delay functional and impulsive differential equation, the sufficient condition with time delay for the permanence of the system is obtained, and it is proved that time delays, pulse vaccination and vertical transmission can bring obvious effects on the dynamics behaviors of the model.

  14. Traveling Wave Solutions for Epidemic Cholera Model with Disease-Related Death

    OpenAIRE

    Tianran Zhang; Qingming Gou

    2014-01-01

    Based on Codeço's cholera model (2001), an epidemic cholera model that incorporates the pathogen diffusion and disease-related death is proposed. The formula for minimal wave speed c ∗ is given. To prove the existence of traveling wave solutions, an invariant cone is constructed by upper and lower solutions and Schauder's fixed point theorem is applied. The nonexistence of traveling wave solutions is proved by two-sided Laplace transform. However, to apply two-sided Laplace transform, the pri...

  15. Nonstandard finite difference scheme for SIRS epidemic model with disease-related death

    Science.gov (United States)

    Fitriah, Z.; Suryanto, A.

    2016-04-01

    It is well known that SIRS epidemic with disease-related death can be described by a system of nonlinear ordinary differential equations (NL ODEs). This model has two equilibrium points where their existence and stability properties are determined by the basic reproduction number [1]. Besides the qualitative properties, it is also often needed to solve the system of NL ODEs. Euler method and 4th order Runge-Kutta (RK4) method are often used to solve the system of NL ODEs. However, both methods may produce inconsistent qualitative properties of the NL ODEs such as converging to wrong equilibrium point, etc. In this paper we apply non-standard finite difference (NSFD) scheme (see [2,3]) to approximate the solution of SIRS epidemic model with disease-related death. It is shown that the discrete system obtained by NSFD scheme is dynamically consistent with the continuous model. By our numerical simulations, we find that the solutions of NSFD scheme are always positive, bounded and convergent to the correct equilibrium point for any step size of integration (h), while those of Euler or RK4 method have the same properties only for relatively small h.

  16. Coupling infectious diseases, human preventive behavior, and networks--a conceptual framework for epidemic modeling.

    Science.gov (United States)

    Mao, Liang; Yang, Yan

    2012-01-01

    Human-disease interactions involve the transmission of infectious diseases among individuals and the practice of preventive behavior by individuals. Both infectious diseases and preventive behavior diffuse simultaneously through human networks and interact with one another, but few existing models have coupled them together. This article proposes a conceptual framework to fill this knowledge gap and illustrates the model establishment. The conceptual model consists of two networks and two diffusion processes. The two networks include: an infection network that transmits diseases and a communication network that channels inter-personal influence regarding preventive behavior. Both networks are composed of same individuals but different types of interactions. This article further introduces modeling approaches to formulize such a framework, including the individual-based modeling approach, network theory, disease transmission models and behavioral models. An illustrative model was implemented to simulate a coupled-diffusion process during an influenza epidemic. The simulation outcomes suggest that the transmission probability of a disease and the structure of infection network have profound effects on the dynamics of coupled-diffusion. The results imply that current models may underestimate disease transmissibility parameters, because human preventive behavior has not been considered. This issue calls for a new interdisciplinary study that incorporates theories from epidemiology, social science, behavioral science, and health psychology. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Varying total population enhances disease persistence: Qualitative analysis on a diffusive SIS epidemic model

    Science.gov (United States)

    Li, Huicong; Peng, Rui; Wang, Feng-Bin

    2017-01-01

    This paper performs qualitative analysis on an SIS epidemic reaction-diffusion system with a linear source in spatially heterogeneous environment. The main feature of our model lies in that its total population number varies, compared to its counterpart proposed by Allen et al. [2]. The uniform bounds of solutions are derived, based on which, the threshold dynamics in terms of the basic reproduction number is established and the global stability of the unique endemic equilibrium is discussed when spatial environment is homogeneous. In particular, the asymptotic profile of endemic equilibria is determined if the diffusion rate of the susceptible or infected population is small or large. The theoretical results show that a varying total population can enhance persistence of infectious disease, and therefore the disease becomes more threatening and harder to control.

  18. Transmission Dynamics and Final Epidemic Size of Ebola Virus Disease Outbreaks with Varying Interventions.

    Science.gov (United States)

    Barbarossa, Maria Vittoria; Dénes, Attila; Kiss, Gábor; Nakata, Yukihiko; Röst, Gergely; Vizi, Zsolt

    2015-01-01

    The 2014 Ebola Virus Disease (EVD) outbreak in West Africa was the largest and longest ever reported since the first identification of this disease. We propose a compartmental model for EVD dynamics, including virus transmission in the community, at hospitals, and at funerals. Using time-dependent parameters, we incorporate the increasing intensity of intervention efforts. Fitting the system to the early phase of the 2014 West Africa Ebola outbreak, we estimate the basic reproduction number as 1.44. We derive a final size relation which allows us to forecast the total number of cases during the outbreak when effective interventions are in place. Our model predictions show that, as long as cases are reported in any country, intervention strategies cannot be dismissed. Since the main driver in the current slowdown of the epidemic is not the depletion of susceptibles, future waves of infection might be possible, if control measures or population behavior are relaxed.

  19. [Study of epidemic area on Tsutsugamushi disease in Taizhou from 2013 to 2014].

    Science.gov (United States)

    He, Y L; Yang, H Y; Yu, C X; Zhang, X; Yi, Q H; Ma, Z L; Cha, J; Xu, X B; Zhang, Q; Dai, W J; Qian, W J; Yin, J; Zhu, S J; Xu, Z

    2017-03-06

    Objective: To study the epidemiological characteristics of tsutsugamushi disease, and to confirm the existence of the disease's epidemic foci in Taizhou. Methods: From 2013 to 2014, Dongxing town hospital and Xingqiao town hospital were selected as specimen collection sites in Jingjiang city. Blood samples (5 ml) were collected from 40 patients with acute tsutsugamushi disease. A total of 59 rodents were captured with cage night method in the survey sites at 5, 7, 9, 10, and 11 months in 2013, from which, the spleen, liver, and kidney specimens were selected. Chigger mites were captured by small blackboard method and from the ears of the captured rodents. A total of 226 small blackboards were laid, 27 mites were captured, and the samples were grounded into suspension. Nested-polymerase chain reaction and cell and tissue culture techniques were used to test the specimen from the probable patients, host animals and chigger mites. Results: Among the 40 acute tsutsugamushi disease blood samples, 29 were found to meet the test requirements, 17 were positive for orientia tsutsugamushi nucleic acid with 59% of the positive rate, and 1 stran orientia tsutsugamushi was isolated. 59 rats were captured and the density of mice was 5.5%. Among them, there were 26 Mus musculus (2.4%), 18 Rattus flavipectus (1.7%) and 15 Smelly shrew (density 1.4%). 1 Smelly shrew was tested positive for orientia tsutsugamushi nucleic acid, and the negative results were found in the other rodent specimens. 27 Chigge mites were collected by small blackboard method and the density of mites was 0.12 for each blackboard, among which 3 larvae and 24 nymphs were found. 33 Chigger mites were collected from the ears of 3 Smelly shrew, and the density of the mite was 11 per mouse. All the captured Chigger mites were identified as Leptotrombidium scutellare and 1 group of specimens of Chigger mites from the external environment were positive for orientia tsutsugamushi nucleic acid. Conclusion: There was a

  20. Disease control implications of India's changing multi-drug resistant tuberculosis epidemic.

    Directory of Open Access Journals (Sweden)

    Sze-Chuan Suen

    Full Text Available BACKGROUND: Multi-drug resistant tuberculosis (MDR TB is a major health challenge in India that is gaining increasing public attention, but the implications of India's evolving MDR TB epidemic are poorly understood. As India's MDR TB epidemic is transitioning from a treatment-generated to transmission-generated epidemic, we sought to evaluate the potential effectiveness of the following two disease control strategies on reducing the prevalence of MDR TB: a improving treatment of non-MDR TB; b shortening the infectious period between the activation of MDR TB and initiation of effective MDR treatment. METHODS AND FINDINGS: We developed a dynamic transmission microsimulation model of TB in India. The model followed individuals by age, sex, TB status, drug resistance status, and treatment status and was calibrated to Indian demographic and epidemiologic TB time trends. The main effectiveness measure was reduction in the average prevalence reduction of MDR TB over the ten years after control strategy implementation. We find that improving non-MDR cure rates to avoid generating new MDR cases will provide substantial non-MDR TB benefits but will become less effective in reducing MDR TB prevalence over time because more cases will occur from direct transmission--by 2015, the model estimates 42% of new MDR cases are transmission-generated and this proportion continues to rise over time, assuming equal transmissibility of MDR and drug-susceptible TB. Strategies that disrupt MDR transmission by shortening the time between MDR activation and treatment are projected to provide greater reductions in MDR prevalence compared with improving non-MDR treatment quality: implementing MDR diagnostic improvements in 2017 is expected to reduce MDR prevalence by 39%, compared with 11% reduction from improving non-MDR treatment quality. CONCLUSIONS: As transmission-generated MDR TB becomes a larger driver of the MDR TB epidemic in India, rapid and accurate MDR TB

  1. Traveling Wave Solutions for Epidemic Cholera Model with Disease-Related Death

    Directory of Open Access Journals (Sweden)

    Tianran Zhang

    2014-01-01

    Full Text Available Based on Codeço’s cholera model (2001, an epidemic cholera model that incorporates the pathogen diffusion and disease-related death is proposed. The formula for minimal wave speed c∗ is given. To prove the existence of traveling wave solutions, an invariant cone is constructed by upper and lower solutions and Schauder’s fixed point theorem is applied. The nonexistence of traveling wave solutions is proved by two-sided Laplace transform. However, to apply two-sided Laplace transform, the prior estimate of exponential decrease of traveling wave solutions is needed. For this aim, a new method is proposed, which can be applied to reaction-diffusion systems consisting of more than three equations.

  2. Traveling wave solutions for epidemic cholera model with disease-related death.

    Science.gov (United States)

    Zhang, Tianran; Gou, Qingming

    2014-01-01

    Based on Codeço's cholera model (2001), an epidemic cholera model that incorporates the pathogen diffusion and disease-related death is proposed. The formula for minimal wave speed c (∗) is given. To prove the existence of traveling wave solutions, an invariant cone is constructed by upper and lower solutions and Schauder's fixed point theorem is applied. The nonexistence of traveling wave solutions is proved by two-sided Laplace transform. However, to apply two-sided Laplace transform, the prior estimate of exponential decrease of traveling wave solutions is needed. For this aim, a new method is proposed, which can be applied to reaction-diffusion systems consisting of more than three equations.

  3. The effect of transmission route on plant virus epidemic development and disease control.

    Science.gov (United States)

    Jeger, Michael J; Madden, Laurence V; van den Bosch, Frank

    2009-05-21

    A model for indirect vector transmission and epidemic development of plant viruses is extended to consider direct transmission through vector mating. A basic reproduction number is derived which is the sum of the R(0) values specific for three transmission routes. We analyse the model to determine the effect of direct transmission on plant disease control directed against indirect transmission. Increasing the rate of horizontal sexual transmission means that vector control rate or indirect transmission rate must be increased/decreased substantially to maintain R(0) at a value less than 1. By contrast, proportionately increasing the probability of transovarial transmission has little effect. Expressions are derived for the steady-state values of the viruliferous vector population. There is clear advantage for an insect virus in indirect transmission to plants, especially where the sexual and transovarial transmission rates are low; however information on virulence-transmissibility relationships is required to explain the evolution of a plant virus from an insect virus.

  4. Simulation modelling of population dynamics of mosquito vectors for rift valley Fever virus in a disease epidemic setting.

    Directory of Open Access Journals (Sweden)

    Clement N Mweya

    Full Text Available Rift Valley Fever (RVF is weather dependent arboviral infection of livestock and humans. Population dynamics of mosquito vectors is associated with disease epidemics. In our study, we use daily temperature and rainfall as model inputs to simulate dynamics of mosquito vectors population in relation to disease epidemics.Time-varying distributed delays (TVDD and multi-way functional response equations were implemented to simulate mosquito vectors and hosts developmental stages and to establish interactions between stages and phases of mosquito vectors in relation to vertebrate hosts for infection introduction in compartmental phases. An open-source modelling platforms, Universal Simulator and Qt integrated development environment were used to develop models in C++ programming language. Developed models include source codes for mosquito fecundity, host fecundity, water level, mosquito infection, host infection, interactions, and egg time. Extensible Markup Language (XML files were used as recipes to integrate source codes in Qt creator with Universal Simulator plug-in. We observed that Floodwater Aedines and Culicine population continued to fluctuate with temperature and water level over simulation period while controlled by availability of host for blood feeding. Infection in the system was introduced by floodwater Aedines. Culicines pick infection from infected host once to amplify disease epidemic. Simulated mosquito population show sudden unusual increase between December 1997 and January 1998 a similar period when RVF outbreak occurred in Ngorongoro district.Findings presented here provide new opportunities for weather-driven RVF epidemic simulation modelling. This is an ideal approach for understanding disease transmission dynamics towards epidemics prediction, prevention and control. This approach can be used as an alternative source for generation of calibrated RVF epidemics data in different settings.

  5. High blood pressure: the foundation for epidemic cardiovascular disease in African populations.

    Science.gov (United States)

    Cooper, Richard S; Amoah, Albert G B; Mensah, George A

    2003-01-01

    High-blood pressure is a powerful independent risk factor for death from heart disease and stroke. It is also a common clinical condition affecting more than 600 million persons worldwide and seen in nearly all populations. Although reliable, large-scale, population-based data on high blood pressure in sub-Saharan Africa (SSA) are limited, recent studies provide important and worrisome findings in both epidemiology and clinical outcomes. Although overall hypertension prevalence is between 10%-15%, prevalence rates as high as 30%-32% have been reported in middle-income urban and some rural areas. Importantly, hypertension awareness, treatment, and control rates as low as 20%, 10%, and 1%, respectively have also been found. Stroke has been by far the most common clinical sequela. In most SSA settings, hypertension control assumes a relatively low priority and little experience exists in implementing sustainable and successful programs for drug treatment. Rapid urbanization and transition from agrarian life to the wage-earning economy of city life continue to fuel increases in average blood pressure levels and prevalence of hypertension. Although the true burden of high blood pressure in sub-Saharan Africa remains largely unmeasured, compelling preliminary evidence suggests that it is the foundation for epidemic cardiovascular disease in Africa and already contributes substantively to death and disability from stroke, heart failure, and kidney failure in this region. Success in limiting this epidemic in SSA will depend heavily on the implementation of sustainable and aggressive population-based programs for high blood pressure awareness, prevention, treatment, and control. It will be critical to obtain investments in improved surveillance and program-relevant research to provide the evidence base for policy development and effective hypertension prevention and control.

  6. Effect of crop growth and canopy filtration on the dynamics of plant disease epidemics spread by aerially dispersed spores.

    Science.gov (United States)

    Ferrandino, F J

    2008-05-01

    Most mathematical models of plant disease epidemics ignore the growth and phenology of the host crop. Unfortunately, reports of disease development are often not accompanied by a simultaneous and commensurate evaluation of crop development. However, the time scale for increases in the leaf area of field crops is comparable to the time scale of epidemics. This simultaneous development of host and pathogen has many ramifications on the resulting plant disease epidemic. First, there is a simple dilution effect resulting from the introduction of new healthy leaf area with time. Often, measurements of disease levels are made pro rata (per unit of host leaf area or total root length or mass). Thus, host growth will reduce the apparent infection rate. A second, related effect, has to do with the so-called "correction factor," which accounts for inoculum falling on already infected tissue. This factor accounts for multiple infection and is given by the fraction of the host tissue that is susceptible to disease. As an epidemic develops, less and less tissue is open to infection and the initial exponential growth slows. Crop growth delays the impact of this limiting effect and, therefore, tends to increase the rate of disease progress. A third and often neglected effect arises when an increase in the density of susceptible host tissue results in a corresponding increase in the basic reproduction ratio, R(0), defined as the ratio of the total number of daughter lesions produced to the number of original mother lesions. This occurs when the transport efficiency of inoculum from infected to susceptible host is strongly dependent on the spatial density of plant tissue. Thus, crop growth may have a major impact on the development of plant disease epidemics occurring during the vegetative phase of crop growth. The effects that these crop growth-related factors have on plant disease epidemics spread by airborne spores are evaluated using mathematical models and their importance is

  7. Hypothetical constructs, hypothetical questions, and the expert witness.

    Science.gov (United States)

    Brodsky, Stanley L; Titcomb, Caroline; Sams, David M; Dickson, Kara; Benda, Yves

    2012-01-01

    Professor John Henry Wigmore in 1940 described the hypothetical question as an intolerable obstruction of truth. Since that time, the nature and application of the hypothetical question in the courtroom, as well as responses to this line of questioning during expert testimony, have been sources of controversy. Governed by legal philosophical foundations, the hypothetical construct addresses what there is, in a general sense, and what can or ought to be. Alexy (2004) has described the nature of legal philosophy as the epistemological question of what we can know. This article begins by examining the philosophical underpinnings, legal parameters, and teaching purposes of posing hypothetical queries. A social-psychological backdrop for the use of hypothetical questions is then discussed followed by a broader discussion of the hypothetical question's role in court procedures. This paper identifies hypothetical questions used in court as devices to elicit information, or as predictions that potentially change underlying factual interpretations of evidence. In particular, on cross examination hypothetical questions seek to make opposing experts assume facts that are incongruent with their conclusions or opinions. Sometimes in these situations, experts are led to re-evaluate opinions based on alternative understandings of events and behaviors. Thus, this paper's final aim is to explore a foundational understanding of hypothetical questions asked of expert witnesses with special reference to mental health issues. Options for responding to hypothetical questions on the stand are considered along the dimensions of assertiveness-passivity, compliance-resistance, and possible redefinitions of the hypothetical issues.

  8. Porcine Epidemic Diarrhea in Europe: In-Detail Analyses of Disease Dynamics and Molecular Epidemiology

    Directory of Open Access Journals (Sweden)

    Dennis Hanke

    2017-07-01

    Full Text Available Porcine epidemic diarrhea (PED is an acute and highly contagious enteric disease of swine caused by the eponymous virus (PEDV which belongs to the genus Alphacoronavirus within the Coronaviridae virus family. Following the disastrous outbreaks in Asia and the United States, PEDV has been detected also in Europe. In order to better understand the overall situation, the molecular epidemiology, and factors that might influence the most variable disease impact; 40 samples from swine feces were collected from different PED outbreaks in Germany and other European countries and sequenced by shot-gun next-generation sequencing. A total of 38 new PEDV complete coding sequences were generated. When compared on a global scale, all investigated sequences from Central and South-Eastern Europe formed a rather homogeneous PEDV S INDEL cluster, suggesting a recent re-introduction. However, in-detail analyses revealed two new clusters and putative ancestor strains. Based on the available background data, correlations between clusters and location, farm type or clinical presentation could not be established. Additionally, the impact of secondary infections was explored using the metagenomic data sets. While several coinfections were observed, no correlation was found with disease courses. However, in addition to the PEDV genomes, ten complete viral coding sequences from nine different data sets were reconstructed each representing new virus strains. In detail, three pasivirus A strains, two astroviruses, a porcine sapelovirus, a kobuvirus, a porcine torovirus, a posavirus, and an enterobacteria phage were almost fully sequenced.

  9. Public health and public trust: Survey evidence from the Ebola Virus Disease epidemic in Liberia.

    Science.gov (United States)

    Blair, Robert A; Morse, Benjamin S; Tsai, Lily L

    2017-01-01

    Trust in government has long been viewed as an important determinant of citizens' compliance with public health policies, especially in times of crisis. Yet evidence on this relationship remains scarce, particularly in the developing world. We use results from a representative survey conducted during the 2014-15 Ebola Virus Disease (EVD) epidemic in Monrovia, Liberia to assess the relationship between trust in government and compliance with EVD control interventions. We find that respondents who expressed low trust in government were much less likely to take precautions against EVD in their homes, or to abide by government-mandated social distancing mechanisms designed to contain the spread of the virus. They were also much less likely to support potentially contentious control policies, such as "safe burial" of EVD-infected bodies. Contrary to stereotypes, we find no evidence that respondents who distrusted government were any more or less likely to understand EVD's symptoms and transmission pathways. While only correlational, these results suggest that respondents who refused to comply may have done so not because they failed to understand how EVD is transmitted, but rather because they did not trust the capacity or integrity of government institutions to recommend precautions and implement policies to slow EVD's spread. We also find that respondents who experienced hardships during the epidemic expressed less trust in government than those who did not, suggesting the possibility of a vicious cycle between distrust, non-compliance, hardships and further distrust. Finally, we find that respondents who trusted international non-governmental organizations (INGOs) were no more or less likely to support or comply with EVD control policies, suggesting that while INGOs can contribute in indispensable ways to crisis response, they cannot substitute for government institutions in the eyes of citizens. We conclude by discussing the implications of our findings for future

  10. Real time bayesian estimation of the epidemic potential of emerging infectious diseases.

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    Luís M A Bettencourt

    Full Text Available BACKGROUND: Fast changes in human demographics worldwide, coupled with increased mobility, and modified land uses make the threat of emerging infectious diseases increasingly important. Currently there is worldwide alert for H5N1 avian influenza becoming as transmissible in humans as seasonal influenza, and potentially causing a pandemic of unprecedented proportions. Here we show how epidemiological surveillance data for emerging infectious diseases can be interpreted in real time to assess changes in transmissibility with quantified uncertainty, and to perform running time predictions of new cases and guide logistics allocations. METHODOLOGY/PRINCIPAL FINDINGS: We develop an extension of standard epidemiological models, appropriate for emerging infectious diseases, that describes the probabilistic progression of case numbers due to the concurrent effects of (incipient human transmission and multiple introductions from a reservoir. The model is cast in terms of surveillance observables and immediately suggests a simple graphical estimation procedure for the effective reproductive number R (mean number of cases generated by an infectious individual of standard epidemics. For emerging infectious diseases, which typically show large relative case number fluctuations over time, we develop a bayesian scheme for real time estimation of the probability distribution of the effective reproduction number and show how to use such inferences to formulate significance tests on future epidemiological observations. CONCLUSIONS/SIGNIFICANCE: Violations of these significance tests define statistical anomalies that may signal changes in the epidemiology of emerging diseases and should trigger further field investigation. We apply the methodology to case data from World Health Organization reports to place bounds on the current transmissibility of H5N1 influenza in humans and establish a statistical basis for monitoring its evolution in real time.

  11. The effects of wealth, occupation, and immigration on epidemic mortality from selected infectious diseases and epidemics in Holyoke township, Massachusetts, 1850−1912

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    Susan Hautaniemi Leonard

    2015-11-01

    Full Text Available Background: Previous research suggests individual-level socioeconomic circumstances and resources may be especially salient influences on mortality within the broader context of social, economic, and environmental factors affecting urban 19th century mortality. Objective: We sought to test individual-level socioeconomic effects on mortality from infectious and often epidemic diseases in the context of an emerging New England industrial mill town. Methods: We analyze mortality data from comprehensive death records and a sample of death records linked to census data, for an emergent industrial New England town, to analyze infectious mortality and model socioeconomic effects using Poisson rate regression. Results: Despite our expectations that individual resources might be especially salient in the harsh mortality setting of a crowded, rapidly growing, emergent, industrial mill town with high levels of impoverishment, infectious mortality was not significantly lowered by individual socio-economic status or resources.

  12. A General Stochastic Information Diffusion Model in Social Networks Based on Epidemic Diseases

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    Hamidreza Sotoodeh

    2013-09-01

    Full Text Available Social networks are an important infrastructure forinformation, viruses and innovations propagation.Since users’behavior has influenced by other users’ activity, some groups of people would be made regard to similarity of users’interests. On the other hand, dealing with many events in real worlds, can be justified in social networks; spreadingdisease is one instance of them. People’s manner and infection severity are more important parameters in dissemination of diseases. Both of these reasons derive, whether the diffusion leads to an epidemic or not. SIRS is a hybrid model of SIR and SIS disease models to spread contamination. A person in this model can be returned tosusceptible state after it removed. According to communities which are established on the social network, we use thecompartmental type of SIRS model. During this paper, a general compartmental information diffusion model wouldbe proposed and extracted some of the beneficial parameters to analyze our model. To adapt our model to realistic behaviors, we use Mark ovian model, which would be helpful to create a stochastic manner of the proposed model.In the case of random model, we can calculate probabilities of transaction between states and predicting value of each state. The comparison between two mode of themodel shows that, the prediction of population would beverified in each state.

  13. [Clostridium difficile epidemic, Chile 2012: report of the Chilean Society for Infectious Diseases. A scientific historical analysis].

    Science.gov (United States)

    Cabello, Felipe

    2012-08-01

    A Summary Report from the Chilean Society for Infectious Diseases regarding the presence of a Clostridium difficile epidemic with several fatalities in Chile's premier emergency public hospital in Santiago is used to make a scientific historical analysis of the situation. This Summary Report identifies several hygienic and sanitary shortcomings that may have played a role in triggering this major epidemic. These include deficiencies in hand washing policies, overcrowding of beds in wards, relaxation of infection control policies, antimicrobial therapy mismanagement and lack of laboratory support. The relevance of these shortcomings to the epidemic is further supported by the lack of any laboratory evidence for the presence of hypertoxigenic strains of C. difficile. In an era of whole genome sequencing of pathogens to guide therapy, prevention, and epidemiological studies of infectious diseases, it is illuminating and sobering, as this report so clearly demonstrates, to realize that many epidemics of hospital infections still result from breakdowns in classical and ancillary asepsis and infection control measures developed in the nineteenth century by Semmelweis, Nightingale and Lister. As the Summary Report suggests, such hygienic breakdowns in countries like Chile are usually brought about by lack of implementation and regulation of national hospital infection control policies resulting from the shift of economic resources from the public to the private sector, despite the former being responsible for health care of 80% of the population.

  14. Phylodynamic reconstruction of O CATHAY topotype foot-and-mouth disease virus epidemics in the Philippines.

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    Di Nardo, Antonello; Knowles, Nick J; Wadsworth, Jemma; Haydon, Daniel T; King, Donald P

    2014-01-01

    Reconstructing the evolutionary history, demographic signal and dispersal processes from viral genome sequences contributes to our understanding of the epidemiological dynamics underlying epizootic events. In this study, a Bayesian phylogenetic framework was used to explore the phylodynamics and spatio-temporal dispersion of the O CATHAY topotype of foot-and-mouth disease virus (FMDV) that caused epidemics in the Philippines between 1994 and 2005. Sequences of the FMDV genome encoding the VP1 showed that the O CATHAY FMD epizootic in the Philippines resulted from a single introduction and was characterised by three main transmission hubs in Rizal, Bulacan and Manila Provinces. From a wider regional perspective, phylogenetic reconstruction of all available O CATHAY VP1 nucleotide sequences identified three distinct sub-lineages associated with country-based clusters originating in Hong Kong Special Administrative Region (SAR), the Philippines and Taiwan. The root of this phylogenetic tree was located in Hong Kong SAR, representing the most likely source for the introduction of this lineage into the Philippines and Taiwan. The reconstructed O CATHAY phylodynamics revealed three chronologically distinct evolutionary phases, culminating in a reduction in viral diversity over the final 10 years. The analysis suggests that viruses from the O CATHAY topotype have been continually maintained within swine industries close to Hong Kong SAR, following the extinction of virus lineages from the Philippines and the reduced number of FMD cases in Taiwan.

  15. Childhood cardiovascular risk factors in South Asians: A cause of concern for adult cardiovascular disease epidemic

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    Duggirala Sivaram Prasad

    2011-01-01

    Full Text Available Cardiovascular risk factors in children are increasing at an alarming rate in the western world. However, there is limited information regarding these in the South Asian children. This review attempts at summarizing such evidence. South Asians are remarkable for the earlier onset of adult cardiovascular disease (CVD by almost a decade compared to the Caucasians. We identified published literature, mainly on PubMed, Embase and Cochrane library using specific search terms such as lipid abnormalities, high blood pressure, hyperglycemia, tobacco use, obesity, physical inactivity, and unhealthy dietary practices. Atherosclerotic CVD processes begin early in childhood and are influenced over the life course by genetic and potentially modifiable risk factors and environmental exposure. 80% of adult CVD burden will fall on the developing nations by 2020. The concept of primordial prevention is fast emerging as a necessary prevention tool to curb adult CVD epidemic. Established guidelines and proven preventive strategies on cardiovascular health exist; however, are always implemented half-heartedly. Composite screening and prediction tools for adults can be adapted and validated in children tailored to South Asian population. South Asian children could be at a greater risk of developing cardiovascular risk factors at an earlier stage, thus, timely interventions are imperative.

  16. The Emerging Epidemic of Cardiovascular Risk Factors and Atherosclerotic Disease in Developing Countries.

    Science.gov (United States)

    Teo, Koon K; Dokainish, Hisham

    2017-03-01

    Cardiovascular disease (CVD) and its risk factors, which are major health burdens in high-income countries, are a growing problem in developing or lower-income countries, where the vast majority of CVD now occurs. Two case-control studies, INTERHEART and INTERSTROKE, which included a majority of patients from developing countries, were seminal in identifying common risk factors explaining the vast majority of risk for acute myocardial infarction and stroke, respectively. The population-based Prospective Urban and Rural Epidemiological (PURE) study, which included > 150,000 participants, also with a majority from developing countries, found that although high-income countries were at highest cardiovascular (CV) risk, they had the lowest incidence of CVD and associated case-fatality rates, whereas patients in low-income countries had the lowest CV risk and yet the highest CVD and case-fatality rates. The PURE study also demonstrated relatively low rates of CV medicine use in high- and middle-income countries, but even lower rates in low-income countries, where these medicines were often either unavailable or unaffordable. The PURE study also demonstrated that control of CV risk factors and adherence to lifestyle modifications, although suboptimal globally, were poorest in low-income countries. Taken together, these data identify common CV risk factors requiring targeted, systematic, sustained, and effective interventions in developing countries to mitigate the emerging epidemic of CVD in these regions of the world.

  17. Modeling the epidemic of nonalcoholic fatty liver disease demonstrates an exponential increase in burden of disease.

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    Estes, Chris; Razavi, Homie; Loomba, Rohit; Younossi, Zobair; Sanyal, Arun J

    2017-08-12

    Nonalcoholic fatty liver disease (NAFLD) and resulting nonalcoholic steatohepatitis (NASH) are highly prevalent in the US, where they are a growing cause of cirrhosis and hepatocellular carcinoma (HCC), and increasingly, an indicator for liver transplantation. A Markov model was used to forecast NAFLD disease progression. Incidence of NAFLD was based on historical and projected changes in adult prevalence of obesity and type 2 diabetes mellitus (DM). Assumptions were derived from published literature where available, and validated using national surveillance data for incidence of NAFLD-related HCC. Projected changes in NAFLD-related cirrhosis, advanced liver disease, and liver-related mortality were quantified through 2030. Prevalent NAFLD cases are forecasted to increase 21%, from 83.1 (2015) to 100.9 million (2030), while prevalent NASH cases will increase 63% from 16.52 to 27.00 million cases. Overall NAFLD prevalence among the adult population (aged ≥15 years) is projected at 33.5% in 2030, and the median age of the NAFLD population will increase from 50 to 55 years during 2015-2030. In 2015, approximately 20% of NAFLD cases were classified as NASH, increasing to 27% by 2030, a reflection of both disease progression and an aging population. Incidence of decompensated cirrhosis will increase 168% to 105,430 cases by 2030, while incidence of HCC will increase by 137% to 12,240 cases. Liver deaths will increase 178% to an estimated 78,300 deaths in 2030. During 2015-2030, there are nearly 800,000 excess liver deaths. With continued high rates of adult obesity and DM, and an aging population, NAFLD-related liver disease and mortality will increase in the US. Strategies to slow the growth of NAFLD cases and therapeutic options are necessary to mitigate disease burden. This article is protected by copyright. All rights reserved. © 2017 by the American Association for the Study of Liver Diseases.

  18. Kawasaki disease and the emerging coronary artery disease epidemic in India: is there a correlation?

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    Singh, Surjit; Aulakh, Roosy; Kawasaki, Tomisaku

    2014-04-01

    Although Kawasaki disease (KD) is now being increasingly reported from India, the vast majority of children with KD are still not being diagnosed and treated. A recent study from Chandigarh has shown that the incidence of KD is at least 4.54/100,000 children below 15 y of age. Extrapolations of this figure suggest that a minimum of 17,417 new cases of KD would be occurring every year in our country. A significant proportion of these children may develop coronary artery abnormalities. These children would then be at risk of developing myocardial ischemia as young adults. It is authors' contention that (undiagnosed) KD in childhood may be contributing to the growing pool of coronary artery disease (CAD) in India. Similarly, a missed diagnosis of KD in childhood should be considered as a possibility while evaluating adults with CAD, especially when there are no overt risk factors and no family history of the disease.

  19. Accuracy of Zika virus disease case definition during simultaneous Dengue and Chikungunya epidemics.

    Science.gov (United States)

    Braga, José Ueleres; Bressan, Clarisse; Dalvi, Ana Paula Razal; Calvet, Guilherme Amaral; Daumas, Regina Paiva; Rodrigues, Nadia; Wakimoto, Mayumi; Nogueira, Rita Maria Ribeiro; Nielsen-Saines, Karin; Brito, Carlos; Bispo de Filippis, Ana Maria; Brasil, Patrícia

    2017-01-01

    Zika is a new disease in the American continent and its surveillance is of utmost importance, especially because of its ability to cause neurological manifestations as Guillain-Barré syndrome and serious congenital malformations through vertical transmission. The detection of suspected cases by the surveillance system depends on the case definition adopted. As the laboratory diagnosis of Zika infection still relies on the use of expensive and complex molecular techniques with low sensitivity due to a narrow window of detection, most suspected cases are not confirmed by laboratory tests, mainly reserved for pregnant women and newborns. In this context, an accurate definition of a suspected Zika case is crucial in order for the surveillance system to gauge the magnitude of an epidemic. We evaluated the accuracy of various Zika case definitions in a scenario where Dengue and Chikungunya viruses co-circulate. Signs and symptoms that best discriminated PCR confirmed Zika from other laboratory confirmed febrile or exanthematic diseases were identified to propose and test predictive models for Zika infection based on these clinical features. Our derived score prediction model had the best performance because it demonstrated the highest sensitivity and specificity, 86·6% and 78·3%, respectively. This Zika case definition also had the highest values for auROC (0·903) and R2 (0·417), and the lowest Brier score 0·096. In areas where multiple arboviruses circulate, the presence of rash with pruritus or conjunctival hyperemia, without any other general clinical manifestations such as fever, petechia or anorexia is the best Zika case definition.

  20. Probability of exporting infected carcasses from vaccinated pigs following a foot-and-mouth disease epidemic.

    Science.gov (United States)

    de Vos, Clazien J; Nielen, Mirjam; Lopez, Emelinda; Elbers, Armin R W; Dekker, Aldo

    2010-04-01

    Emergency vaccination is an effective control strategy for foot-and-mouth disease (FMD) epidemics in densely populated livestock areas, but results in a six-month waiting period before exports can be resumed, incurring severe economic consequences for pig exporting countries. In the European Union, a one-month waiting period has been discussed based on negative test results in a final screening. The objective of this study was to analyze the risk of exporting FMD-infected pig carcasses from a vaccinated area: (1) directly after final screening and (2) after a six-month waiting period. A risk model has been developed to estimate the probability that a processed carcass was derived from an FMD-infected pig (P(carc)). Key variables were herd prevalence (P(H)), within-herd prevalence (P(A)), and the probability of detection at slaughter (P(SL)). P(H) and P(A) were estimated using Bayesian inference under the assumption that, despite all negative test results, > or =1 infected pigs were present. Model calculations indicated that P(carc) was on average 2.0 x 10(-5) directly after final screening, and 1.7 x 10(-5) after a six-month waiting period. Therefore, the additional waiting time did not substantially reduce P(carc). The estimated values were worst-case scenarios because only viraemic pigs pose a risk for disease transmission, while seropositive pigs do not. The risk of exporting FMD via pig carcasses from a vaccinated area can further be reduced by heat treatment of pork and/or by excluding high-risk pork products from export.

  1. Accuracy of Zika virus disease case definition during simultaneous Dengue and Chikungunya epidemics

    Science.gov (United States)

    Bressan, Clarisse; Dalvi, Ana Paula Razal; Calvet, Guilherme Amaral; Daumas, Regina Paiva; Rodrigues, Nadia; Wakimoto, Mayumi; Nogueira, Rita Maria Ribeiro; Nielsen-Saines, Karin; Brito, Carlos

    2017-01-01

    Background Zika is a new disease in the American continent and its surveillance is of utmost importance, especially because of its ability to cause neurological manifestations as Guillain-Barré syndrome and serious congenital malformations through vertical transmission. The detection of suspected cases by the surveillance system depends on the case definition adopted. As the laboratory diagnosis of Zika infection still relies on the use of expensive and complex molecular techniques with low sensitivity due to a narrow window of detection, most suspected cases are not confirmed by laboratory tests, mainly reserved for pregnant women and newborns. In this context, an accurate definition of a suspected Zika case is crucial in order for the surveillance system to gauge the magnitude of an epidemic. Methodology We evaluated the accuracy of various Zika case definitions in a scenario where Dengue and Chikungunya viruses co-circulate. Signs and symptoms that best discriminated PCR confirmed Zika from other laboratory confirmed febrile or exanthematic diseases were identified to propose and test predictive models for Zika infection based on these clinical features. Results and discussion Our derived score prediction model had the best performance because it demonstrated the highest sensitivity and specificity, 86·6% and 78·3%, respectively. This Zika case definition also had the highest values for auROC (0·903) and R2 (0·417), and the lowest Brier score 0·096. Conclusions In areas where multiple arboviruses circulate, the presence of rash with pruritus or conjunctival hyperemia, without any other general clinical manifestations such as fever, petechia or anorexia is the best Zika case definition. PMID:28650987

  2. Approximate formulae (deduced from a mathematical model) for the characteristics of the interepidemic and epidemic periods of some virus diseases.

    Science.gov (United States)

    Cristea, A L; Deutsch, I; Copelovici, Y

    1992-01-01

    By a qualitative analysis of the solutions of the mathematical model equations (describing the morbidity and susceptibility evolution in a viral epidemics), approximate formulae for the extreme values of the variables and for the duration of the main phases of a multiannual cycle are deduced. These formulae were validated by numerical simulation of the solutions, leading to the exact values of the mentioned essential characteristics of the diseases propagation.

  3. The wisdom of crowds in action: Forecasting epidemic diseases with a web-based prediction market system.

    Science.gov (United States)

    Li, Eldon Y; Tung, Chen-Yuan; Chang, Shu-Hsun

    2016-08-01

    The quest for an effective system capable of monitoring and predicting the trends of epidemic diseases is a critical issue for communities worldwide. With the prevalence of Internet access, more and more researchers today are using data from both search engines and social media to improve the prediction accuracy. In particular, a prediction market system (PMS) exploits the wisdom of crowds on the Internet to effectively accomplish relatively high accuracy. This study presents the architecture of a PMS and demonstrates the matching mechanism of logarithmic market scoring rules. The system was implemented to predict infectious diseases in Taiwan with the wisdom of crowds in order to improve the accuracy of epidemic forecasting. The PMS architecture contains three design components: database clusters, market engine, and Web applications. The system accumulated knowledge from 126 health professionals for 31 weeks to predict five disease indicators: the confirmed cases of dengue fever, the confirmed cases of severe and complicated influenza, the rate of enterovirus infections, the rate of influenza-like illnesses, and the confirmed cases of severe and complicated enterovirus infection. Based on the winning ratio, the PMS predicts the trends of three out of five disease indicators more accurately than does the existing system that uses the five-year average values of historical data for the same weeks. In addition, the PMS with the matching mechanism of logarithmic market scoring rules is easy to understand for health professionals and applicable to predict all the five disease indicators. The PMS architecture of this study affords organizations and individuals to implement it for various purposes in our society. The system can continuously update the data and improve prediction accuracy in monitoring and forecasting the trends of epidemic diseases. Future researchers could replicate and apply the PMS demonstrated in this study to more infectious diseases and wider

  4. PROFILE OF HUMAN RABIES CASES ADMITTED AT EPIDEMIC DISEASES HOSPITAL, BANGALORE, INDIA

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    Mahendra

    2014-05-01

    Full Text Available OBJECTIVES: The present study was carried out with the following objectives 1. To describe the socio demographic profile of human rabies cases 2. To describe the pattern of clinical presentation 3. To assess the quality of data in the case record forms of the human rabies cases TYPE OF STUDY: Case Record Analysis. MATERIAL AND METHODS: Case records of suspect human rabies cases. Data analyzed using proportions. STUDY PERIOD: April 2009 to March 2012. RESULTS: 75 suspected human rabies cases were admitted to the epidemic diseases hospital during the study period. 64 (85.33% of the cases were from the state of Karnataka, 11 (14.67% were from Andhra Pradesh and Tamilnadu. 61 (81.33% were males. 17 (22.67% were children aged ≤ 15 years. 44 (58.67% of the cases were from rural areas. In 71 (94.67% of the victims, the exposure was to dogs. Mean duration of time since bite to seeking admission was 118 days. Category of the wound was documented for 43 (57.33% of the 75 cases. Of these, 40 (93.02% had category III exposure. 61 (81.33% of the case records had data regarding wound toilet and only 12 (19.68% of the victims had performed wound toilet. Only 1 (1.47% of the victims had received rabies immunoglobulin, but had not completed the scheduled vaccination regimen. 43 (67.19% had not received any post exposure prophylaxis. Clinical signs and symptoms of rabies had been entered in 68 (90.67% of the case records, and all had hydrophobia. CONCLUSION: Most of the suspected human rabies cases admitted had not received post exposure prophylaxis or had received incomplete post exposure prophylaxis. The data entered into the case record forms of the patients was mostly incomplete.

  5. Spatial and temporal patterns of chronic wasting disease: fine-scale mapping of a wildlife epidemic in Wisconsin.

    Science.gov (United States)

    Osnas, Erik E; Heisey, Dennis M; Rolley, Robert E; Samuel, Michael D

    2009-07-01

    Emerging infectious diseases threaten wildlife populations and human health. Understanding the spatial distributions of these new diseases is important for disease management and policy makers; however, the data are complicated by heterogeneities across host classes, sampling variance, sampling biases, and the space-time epidemic process. Ignoring these issues can lead to false conclusions or obscure important patterns in the data, such as spatial variation in disease prevalence. Here, we applied hierarchical Bayesian disease mapping methods to account for risk factors and to estimate spatial and temporal patterns of infection by chronic wasting disease (CWD) in white-tailed deer (Odocoileus virginianus) of Wisconsin, U.S.A. We found significant heterogeneities for infection due to age, sex, and spatial location. Infection probability increased with age for all young deer, increased with age faster for young males, and then declined for some older animals, as expected from disease-associated mortality and age-related changes in infection risk. We found that disease prevalence was clustered in a central location, as expected under a simple spatial epidemic process where disease prevalence should increase with time and expand spatially. However, we could not detect any consistent temporal or spatiotemporal trends in CWD prevalence. Estimates of the temporal trend indicated that prevalence may have decreased or increased with nearly equal posterior probability, and the model without temporal or spatiotemporal effects was nearly equivalent to models with these effects based on deviance information criteria. For maximum interpretability of the role of location as a disease risk factor, we used the technique of direct standardization for prevalence mapping, which we develop and describe. These mapping results allow disease management actions to be employed with reference to the estimated spatial distribution of the disease and to those host classes most at risk. Future

  6. Spatial and temporal patterns of chronic wasting disease: Fine-scale mapping of a wildlife epidemic in Wisconsin

    Science.gov (United States)

    Osnas, E.E.; Heisey, D.M.; Rolley, R.E.; Samuel, M.D.

    2009-01-01

    Emerging infectious diseases threaten wildlife populations and human health. Understanding the spatial distributions of these new diseases is important for disease management and policy makers; however, the data are complicated by heterogeneities across host classes, sampling variance, sampling biases, and the space-time epidemic process. Ignoring these issues can lead to false conclusions or obscure important patterns in the data, such as spatial variation in disease prevalence. Here, we applied hierarchical Bayesian disease mapping methods to account for risk factors and to estimate spatial and temporal patterns of infection by chronic wasting disease (CWD) in white-tailed deer (Odocoileus virginianus) of Wisconsin, USA. We found significant heterogeneities for infection due to age, sex, and spatial location. Infection probability increased with age for all young deer, increased with age faster for young males, and then declined for some older animals, as expected from disease-associated mortality and age-related changes in infection risk. We found that disease prevalence was clustered in a central location, as expected under a simple spatial epidemic process where disease prevalence should increase with time and expand spatially. However, we could not detect any consistent temporal or spatiotemporal trends in CWD prevalence. Estimates of the temporal trend indicated that prevalence may have decreased or increased with nearly equal posterior probability, and the model without temporal or spatiotemporal effects was nearly equivalent to models with these effects based on deviance information criteria. For maximum interpretability of the role of location as a disease risk factor, we used the technique of direct standardization for prevalence mapping, which we develop and describe. These mapping results allow disease management actions to be employed with reference to the estimated spatial distribution of the disease and to those host classes most at risk. Future

  7. Neurological images and the predictors for neurological sequelae of epidemic herpangina/hand-foot-mouth disease with encephalomyelitis.

    Science.gov (United States)

    Tsai, Jeng-Dau; Kuo, Hung-Tsung; Chen, Shan-Ming; Lue, Ko-Huang; Sheu, Ji-Nan

    2014-04-01

    Since 1998 in Taiwan, enterovirus (EV) 71 epidemics have caused encephalomyelitis and placed a significant burden on parents and physicians. In this study, we present clinical manifestations, magnetic resonance (MR) imaging findings, and neurological sequelae on epidemic EV-infected patients with encephalomyelitis. Of the 46 patients, 14 patients presented with neurological sequelae; of them, 3 patients suffered from complications of mental regression. Predictors of unfavorable neurological sequelae were myoclonic jerks (> 4 times/night) and pleocytosis (167/μL) of the cerebrospinal fluid (CSF). Results from viral culture and MR imaging indicated that positive identification of EV71 infection was associated significantly with lesions on MR imaging. Our results show that hand-foot-mouth disease carries a higher risk of encephalomyelitis and that frequent myoclonic jerks and pleocytosis of the CSF are risk factors for subsequent neurological sequelae. Positive identification of EV71 might be useful as a predictor of lesions in MR imaging.

  8. Kin groups and trait groups: population structure and epidemic disease selection.

    Science.gov (United States)

    Fix, A G

    1984-10-01

    A Monte Carlo simulation based on the population structure of a small-scale human population, the Semai Senoi of Malaysia, has been developed to study the combined effects of group, kin, and individual selection. The population structure resembles D.S. Wilson's structured deme model in that local breeding populations (Semai settlements) are subdivided into trait groups (hamlets) that may be kin-structured and are not themselves demes. Additionally, settlement breeding populations are connected by two-dimensional stepping-stone migration approaching 30% per generation. Group and kin-structured group selection occur among hamlets the survivors of which then disperse to breed within the settlement population. Genetic drift is modeled by the process of hamlet formation; individual selection as a deterministic process, and stepping-stone migration as either random or kin-structured migrant groups. The mechanism for group selection is epidemics of infectious disease that can wipe out small hamlets particularly if most adults become sick and social life collapses. Genetic resistance to a disease is an individual attribute; however, hamlet groups with several resistant adults are less likely to disintegrate and experience high social mortality. A specific human gene, hemoglobin E, which confers resistance to malaria, is studied as an example of the process. The results of the simulations show that high genetic variance among hamlet groups may be generated by moderate degrees of kin-structuring. This strong microdifferentiation provides the potential for group selection. The effect of group selection in this case is rapid increase in gene frequencies among the total set of populations. In fact, group selection in concert with individual selection produced a faster rate of gene frequency increase among a set of 25 populations than the rate within a single unstructured population subject to deterministic individual selection. Such rapid evolution with plausible rates of

  9. Zika virus epidemic in Brazil. I. Fatal disease in adults: Clinical andlaboratorial aspects

    Science.gov (United States)

    Azevedo, Raimunda S.S.; Araujo, Marialva T.; Martins Filho, Arnaldo J.; Oliveira, Consuelo S.; Nunes, Bruno T.D.; Cruz, Ana C.R.; Nascimento, Ana G.P.A.C.; Medeiros, Rita C.; Caldas, Cezar A.M.; Araujo, Fernando C.; Quaresma, Juarez A.S.; Vasconcelos, Barbara C.B.; Queiroz, Maria G.L.; Travassos da Rosa, Elizabeth S.; Henriques, Daniele F.; Silva, Eliana V.P.; Chiang, Jannifer O.; Martins, Lívia C.; Medeiros, Daniele B.A.; Lima, Juliana A.; Nunes, Márcio R.T.; Cardoso, Jedson F.; Silva, Sandro P.; Shi, Pei-Yong; Tesh, Robert B.; Rodrigues, Sueli G.; Vasconcelos, Pedro F.C.

    2017-01-01

    Background Zika virus (ZIKV) was first detected in Brazil in May 2015 and the country experienced an explosive epidemic. However, recent studies indicate that the introduction of ZIKV occurred in late 2013. Cases of microcephaly and deaths associated with ZIKV infection were identified in Brazil in November, 2015. Objectives To determine the etiology of three fatal adult cases. Study design Here we report three fatal adult cases of ZIKV disease. ZIKV infection in these patients was confirmed by cells culture and/or real-time reverse transcriptase polymerase chain reaction (RT-qPCR) and by antigen detection using immunohistochemical assay. Samples of brain and other selected organs taken at autopsy from three patients were also analyzed by histopathological and immunohistological examination. Results The first patient, a 36-year-old man with lupus and receiving prednisone therapy, developed a fulminant ZIKV infection. At autopsy, RT-qPCR of blood and tissues was positive for ZIKV RNA, and the virus was cultured from an organ homogenate. The second patient, a previously healthy female, 16 years of age, presented classic symptoms of Zika fever, but later developed severe thrombocytopenia, anemia and hemorrhagic manifestations and died. A blood sample taken on the seventh day of her illness was positive RT-PCR for ZIKV RNA and research in the serum was positive for antinuclear factor fine speckled (1/640), suggesting Evans syndrome (hemolytic anemia an autoimmune disorder with immune thrombocytopenic purpura) secondary to ZIKV infection. The third patient was a 20-year-old woman hospitalized with fever, pneumonia and hemorrhages, who died on 13 days after admission. Histopathological changes were observed in all viscera examined. ZIKV antigens were detected by immunohistochemistry in viscera specimens of patients 1 and 3. These three cases demonstrate other potential complications of ZIKV infection, in addition to microcephaly and Guillain-Barre syndrome (GBS), and

  10. Implementation and validation of an economic module in the Be-FAST model to predict costs generated by livestock disease epidemics: Application to classical swine fever epidemics in Spain.

    Science.gov (United States)

    Fernández-Carrión, E; Ivorra, B; Martínez-López, B; Ramos, A M; Sánchez-Vizcaíno, J M

    2016-04-01

    Be-FAST is a computer program based on a time-spatial stochastic spread mathematical model for studying the transmission of infectious livestock diseases within and between farms. The present work describes a new module integrated into Be-FAST to model the economic consequences of the spreading of classical swine fever (CSF) and other infectious livestock diseases within and between farms. CSF is financially one of the most damaging diseases in the swine industry worldwide. Specifically in Spain, the economic costs in the two last CSF epidemics (1997 and 2001) reached jointly more than 108 million euros. The present analysis suggests that severe CSF epidemics are associated with significant economic costs, approximately 80% of which are related to animal culling. Direct costs associated with control measures are strongly associated with the number of infected farms, while indirect costs are more strongly associated with epidemic duration. The economic model has been validated with economic information around the last outbreaks in Spain. These results suggest that our economic module may be useful for analysing and predicting economic consequences of livestock disease epidemics. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. A study of an epidemic of acute respiratory disease in Jaipur town.

    Directory of Open Access Journals (Sweden)

    Mathur M

    2000-04-01

    Full Text Available AIM: To detect an association between the sudden epidemic with respiratory symptoms, and fogging with dichlorovos in Jaipur town and to find out probable mechanism of causation of the epidemic. SUBJECTS AND METHODS: In this community based study of the epidemic, house to house survey of households selected using systematic random sampling was carried out. The incidence in the exposed and unexposed population, the relative risk and attributable risk were calculated. RESULTS: The incidence of cases was high (58.9% in subjects present on roads at the time of fogging as compared to in those who were inside rooms of the houses (5.4% and in those who were not in the locality at that time (1.8% [Relative Risk (RR=32.7 and Attributable Risk (AR=96.9%]. CONCLUSION: High RR and AR in the present epidemic indicate strong association between fogging and occurrence of symptoms. In absence of signs and symptoms of organophosphorus poisoning it suggests that this could have been due to an inappropriate solvent or defective functioning of fog generator, leading to generation of an unusual dark fog, that might have irritated eyes and respiratory tract of exposed residents.

  12. Atmospheric Spread of Foot-and-mouth Disease During The Early Phase of The Uk Epidemic 2001

    Science.gov (United States)

    Sørensen, J. H.; Mikkelsen, T.; Astrup, P.; Alexandersen, S.; Donaldson, A. I.

    Foot-and-mouth disease (FMD) is a highly contagious viral disease in cloven-hoofed domesticated and wild animals. The highly contagious nature of FMD is a reflection of the wide range of species which are susceptible, the enormous quantities of virus liberated by infected animals, the range of excretions and secretions which can be infectious, the stability of the virus in the environment, the multiplicity of routes of infection and the very small doses of virus that can initiate infection in susceptible hosts. One of the routes for the spread of the disease is the atmospheric dispersion of virus exhaled by infected animals. Such spread can be rapid and extensive, and it is known in certain circumstances to have occurred over a distance of several hundred kilometres. For the FMD epidemic in UK in 2001, atmospheric dispersion models were applied in real time in order to describe the atmospheric dispersion of virus for the larger outbreaks of the disease. The operational value of such modelling is first of all to identify risk zones, which is helpful to the emergency management. The paper addresses the modelling techniques and presents results related with the epidemic in UK in 2001.

  13. The development of a massive open online course during the 2014-15 Ebola virus disease epidemic.

    Science.gov (United States)

    Evans, Dabney P; Luffy, Samantha M; Parisi, Stephanie; Del Rio, Carlos

    2017-08-12

    Timely training was urgently needed at the onset of the 2014 Ebola virus disease epidemic. Massive open online courses (MOOCs) have grown in popularity, though little is known about their utility in time-sensitive situations, including infectious disease outbreaks. We created the first English language massive open online course on Ebola virus disease. Designed by a team representing various units of Emory University and six partner institutions, the six module course was aimed at a global general audience but also relevant for health care professionals. Over 7,000 learners from 170 countries participated in the initial course offering. More than a third of learners were from emerging economies, including seven percent from Africa, and another 13% from countries outside the United States who received individuals requiring treatment for Ebola virus disease. Creating and producing the first English language MOOC on EVD in a short time period required effective collaboration and strong coordination between subject matter and course development experts from Emory. Through these collaborative efforts, the development team was able to provide urgently needed training and educational materials while the epidemic of EVD continued to radiate through West Africa. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Taipei's use of a multi-channel mass risk communication program to rapidly reverse an epidemic of highly communicable disease.

    Directory of Open Access Journals (Sweden)

    Muh-Yong Yen

    Full Text Available BACKGROUND: In September 2007, an outbreak of acute hemorrhagic conjunctivitis (AHC occurred in Keelung City and spread to Taipei City. In response to the epidemic, a new crisis management program was implemented and tested in Taipei. METHODOLOGY AND PRINCIPAL FINDINGS: Having noticed that transmission surged on weekends during the Keelung epidemic, Taipei City launched a multi-channel mass risk communications program that included short message service (SMS messages sent directly to approximately 2.2 million Taipei residents on Friday, October 12th, 2007. The public was told to keep symptomatic students from schools and was provided guidelines for preventing the spread of the disease at home. Epidemiological characteristics of Taipei's outbreak were analyzed from 461 sampled AHC cases. Median time from exposure to onset of the disease was 1 day. This was significantly shorter for cases occurring in family clusters than in class clusters (mean+/-SD: 2.6+/-3.2 vs. 4.39+/-4.82 days, p = 0.03, as well as for cases occurring in larger family clusters as opposed to smaller ones (1.2+/-1.7 days vs. 3.9+/-4.0 days, p<0.01. Taipei's program had a significant impact on patient compliance. Home confinement of symptomatic children increased from 10% to 60% (p<0.05 and helped curb the spread of AHC. Taipei experienced a rapid decrease in AHC cases between the Friday of the SMS announcement and the following Monday, October 15, (0.70% vs. 0.36%. By October 26, AHC cases reduced to 0.01%. The success of this risk communication program in Taipei (as compared to Keelung is further reflected through rapid improvements in three epidemic indicators: (1 significantly lower crude attack rates (1.95% vs. 14.92%, p<0.001, (2 a short epidemic period of AHC (13 vs. 34 days, and (3 a quick drop in risk level (1 approximately 2 weeks in Taipei districts that border Keelung (the original domestic epicenter. CONCLUSIONS AND SIGNIFICANCE: The timely launch of this systematic

  15. Chronic wasting disease (CWD) susceptibility of several North American rodents that are sympatric with cervid CWD epidemics

    Science.gov (United States)

    Heisey, D.M.; Mickelsen, N.A.; Schneider, J.R.; Johnson, C.J.; Langenberg, J.A.; Bochsler, P.N.; Keane, D.P.; Barr, D.J.

    2010-01-01

    Chronic wasting disease (CWD) is a highly contagious always fatal neurodegenerative disease that is currently known to naturally infect only species of the deer family, Cervidae. CWD epidemics are occurring in free-ranging cervids at several locations in North America, and other wildlife species are certainly being exposed to infectious material. To assess the potential for transmission, we intracerebrally inoculated four species of epidemic-sympatric rodents with CWD. Transmission was efficient in all species; the onset of disease was faster in the two vole species than the two Peromyscus spp. The results for inocula prepared from CWD-positive deer with or without CWD-resistant genotypes were similar. Survival times were substantially shortened upon second passage, demonstrating adaptation. Unlike all other known prion protein sequences for cricetid rodents that possess asparagine at position 170, our red-backed voles expressed serine and refute previous suggestions that a serine in this position substantially reduces susceptibility to CWD. Given the scavenging habits of these rodent species, the apparent persistence of CWD prions in the environment, and the inevitable exposure of these rodents to CWD prions, our intracerebral challenge results indicate that further investigation of the possibility of natural transmission is warranted. Copyright ?? 2010, American Society for Microbiology. All Rights Reserved.

  16. Disease load at conception predicts survival in later epidemics in a historical French-Canadian cohort, suggesting functional trans-generational effects in humans.

    Directory of Open Access Journals (Sweden)

    Kai Willführ

    Full Text Available OBJECTIVE: Functional trans-generational and parental effects are potentially important determinants of health in several mammals. For humans, the existing evidence is weak. We investigate whether disease exposure triggers functional trans-generational response effects among humans by analyzing siblings who were conceived under different disease loads, and comparing their mortality in later epidemics. Under functional trans-generational response mechanisms, we expect that those who were conceived under high pathogenic stress load will have relatively low mortality during a later epidemic. METHODS: We use data from the Registre de la Population du Québec Ancien, which covers the historical population living in St. Lawrence Valley, Québec, Canada. Children born in 1705-1724 were grouped according to their exposure during conception to the measles 1714-15 epidemic. The 1714-15 epidemic was followed by two mortality crises in 1729-1734. The cause of the first crises in 1729 is not exactly known. The second crisis in 1732 was caused by a smallpox epidemic. Using proportional hazard Cox regression models with multivariate adjustment and with fixed-effects approach that compare siblings, we analyze whether mortality in 1729-1734 is affected by exposure to the 1714-15 epidemic. RESULTS: Children who were conceived during the peak of the measles epidemic of 1714-15 exhibited significantly lower mortality during the 1729-1734 crisis than those who were born before the 1714-15 epidemic (mortality hazard ratio 0.106, p<.05 in multivariate adjusted models; 0.142 p<.1 in sibling comparison models. CONCLUSIONS: The results are consistent with a trans-generational mechanism that functionally responds to pathogen stress and suggest that early disease exposure may be protective later in life. Alternative explanations for the mortality patterns are discussed and shown to be problematic.

  17. Simulated epidemics in an empirical spatiotemporal network of 50,185 sexual contacts

    CERN Document Server

    Rocha, Luis Enrique Correa; Holme, Petter

    2010-01-01

    We study implications of the dynamical and spatial contact structure between Brazilian escorts and sex-buyers for the spreading of sexually transmitted infections (STI). Despite a highly skewed degree distribution diseases spreading in this contact structure have rather well-defined epidemic thresholds. Temporal effects create a broad distribution of outbreak sizes even if the transmission probability is taken to the hypothetical value of 100%. Temporal correlations speed up outbreaks, especially in the early phase, compared to randomized contact structures. The time-ordering and the network topology, on the other hand, slow down the epidemics. Studying compartmental models we show that the contact structure can probably not support the spread of HIV, not even if individuals were sexually active during the acute infection. We investigate hypothetical means of containing an outbreak and find that travel restrictions are about as efficient as removal of the vertices of highest degree. In general, the type of co...

  18. Chronic Non-Communicable Cardiovascular and Pulmonary Disease in sub-Saharan Africa: An Academic Model for Countering the Epidemic

    Science.gov (United States)

    Bloomfield, Gerald S.; Kimaiyo, Sylvester; Carter, E. Jane; Binanay, Cynthia; Corey, G. Ralph; Einterz, Robert M.; Tierney, William M.; Velazquez, Eric J.

    2011-01-01

    Summary Non-communicable diseases are rapidly overtaking infectious, perinatal, nutritional and maternal diseases as the major causes of worldwide death and disability. It is estimated that within the next 10-15 years, the increasing burden of chronic diseases and the ageing of the population will expose the world to an unprecedented burden of chronic diseases. Preventing the potential ramifications of a worldwide epidemic of chronic non-communicable diseases in a sustainable manner requires coordinated, collaborative efforts. Herein we present our collaboration's strategic plan to understand, treat and prevent chronic cardiovascular and pulmonary disease in Western Kenya which builds on a two decade partnership between academic universities in North America and Kenya; the Academic Model Providing Access to Healthcare (AMPATH). We emphasize the importance of training Kenyan clinician-investigators who will ultimately lead efforts in cardiovascular and pulmonary disease care, education and research. This penultimate aim will be achieved by our five main goals. Our goals include creating an administrative core capable of managing operations, develop clinical and clinical research training curricula, enhancing existing technology infrastructure and implementing relevant research programs. Leveraging a strong international academic partnership with respective expertise in cardiovascular medicine, pulmonary medicine and medical informatics we have undertaken to understand and counter cardiovascular and pulmonary disease in Kenya by addressing patient care, teaching and clinical research. PMID:21570512

  19. The impact of spatial arrangements on epidemic disease dynamics and intervention strategies

    Science.gov (United States)

    Kelly, Michael R.; Tien, Joseph H.; Eisenberg, Marisa C.; Lenhart, Suzanne

    2017-01-01

    The role of spatial arrangements on the spread and management strategies of a cholera epidemic is investigated. We consider the effect of human and pathogen movement on optimal vaccination strategies. A metapopulation model is used, incorporating a susceptible–infected–recovered system of differential equations coupled with an equation modelling the concentration of Vibrio cholerae in an aquatic reservoir. The model compared spatial arrangements and varying scenarios to draw conclusions on how to effectively manage outbreaks. The work is motivated by the 2010 cholera outbreak in Haiti. Results give guidance for vaccination strategies in response to an outbreak. PMID:26981710

  20. Serosurveillance of wild deer and wild boar after the epidemic of foot-and-mouth disease in the Netherlands in 2001

    NARCIS (Netherlands)

    Elbers, A.R.W.; Dekker, A.; Dekkers, L.J.M.

    2003-01-01

    Blood samples from 140 wild deer and 208 wild boar shot in the aftermath of the epidemic of foot-and-mouth disease in the Netherlands in 2001 were examined for antibodies to foot-and-mouth disease virus. They were all negative

  1. Analysis of the epidemiological dynamics during the 1982-1983 epidemic of foot-and-mouth disease in Denmark based on molecular high-resolution strain identification

    DEFF Research Database (Denmark)

    Christensen, Laurids Siig; Normann, Preben; Thykier-Nielsen, Søren

    2005-01-01

    An epidemic of foot-and-mouth disease (FMD) causing a total of 23 cases in 1982-1983, primarily on the island of Funen, Denmark, was subjected to molecular epidemiological investigations. In an attempt to exploit the quasi-species nature of foot-and-mouth disease virus strains for molecular high...

  2. Modularity promotes epidemic recurrence

    CERN Document Server

    Jesan, T; Sinha, Sitabhra

    2016-01-01

    The long-term evolution of epidemic processes depends crucially on the structure of contact networks. As empirical evidence indicates that human populations exhibit strong community organization, we investigate here how such mesoscopic configurations affect the likelihood of epidemic recurrence. Through numerical simulations on real social networks and theoretical arguments using spectral methods, we demonstrate that highly contagious diseases that would have otherwise died out rapidly can persist indefinitely for an optimal range of modularity in contact networks.

  3. Modeling the dynamical interaction between epidemics on overlay networks

    CERN Document Server

    Marceau, Vincent; Hébert-Dufresne, Laurent; Allard, Antoine; Dubé, Louis J

    2011-01-01

    Epidemics seldom occur as isolated phenomena. Typically, two or more viral agents spread within the same host population and may interact dynamically with each other. We present a general model where two viral agents interact via an immunity mechanism as they propagate simultaneously on two networks connecting the same set of nodes. Exploiting a correspondence between the propagation dynamics and a dynamical process performing progressive network generation, we develop an analytic approach that accurately captures the dynamical interaction between epidemics on overlay networks. The formalism allows for overlay networks with arbitrary joint degree distribution and overlap. To illustrate the versatility of our approach, we consider a hypothetical delayed intervention scenario in which an immunizing agent is disseminated in a host population to hinder the propagation of an undesirable agent (e.g. the spread of preventive information in the context of an emerging infectious disease).

  4. Abrupt transition to heightened poliomyelitis epidemicity in England and Wales, 1947-1957, associated with a pronounced increase in the geographical rate of disease propagation.

    Science.gov (United States)

    Smallman-Raynor, M R; Cliff, A D

    2014-03-01

    The abrupt transition to heightened poliomyelitis epidemicity in England and Wales, 1947-1957, was associated with a profound change in the spatial dynamics of the disease. Drawing on the complete record of poliomyelitis notifications in England and Wales, we use a robust method of spatial epidemiological analysis (swash-backwash model) to evaluate the geographical rate of disease propagation in successive poliomyelitis seasons, 1940-1964. Comparisons with earlier and later time periods show that the period of heightened poliomyelitis epidemicity corresponded with a sudden and pronounced increase in the spatial rate of disease propagation. This change was observed for both urban and rural areas and points to an abrupt enhancement in the propensity for the geographical spread of polioviruses. Competing theories of the epidemic emergence of poliomyelitis in England and Wales should be assessed in the light of this evidence.

  5. Glyphosate, Hard Water and Nephrotoxic Metals: Are They the Culprits Behind the Epidemic of Chronic Kidney Disease of Unknown Etiology in Sri Lanka?

    Science.gov (United States)

    Jayasumana, Channa; Gunatilake, Sarath; Senanayake, Priyantha

    2014-01-01

    The current chronic kidney disease epidemic, the major health issue in the rice paddy farming areas in Sri Lanka has been the subject of many scientific and political debates over the last decade. Although there is no agreement among scientists about the etiology of the disease, a majority of them has concluded that this is a toxic nephropathy. None of the hypotheses put forward so far could explain coherently the totality of clinical, biochemical, histopathological findings, and the unique geographical distribution of the disease and its appearance in the mid-1990s. A strong association between the consumption of hard water and the occurrence of this special kidney disease has been observed, but the relationship has not been explained consistently. Here, we have hypothesized the association of using glyphosate, the most widely used herbicide in the disease endemic area and its unique metal chelating properties. The possible role played by glyphosate-metal complexes in this epidemic has not been given any serious consideration by investigators for the last two decades. Furthermore, it may explain similar kidney disease epidemics observed in Andra Pradesh (India) and Central America. Although glyphosate alone does not cause an epidemic of chronic kidney disease, it seems to have acquired the ability to destroy the renal tissues of thousands of farmers when it forms complexes with a localized geo environmental factor (hardness) and nephrotoxic metals. PMID:24562182

  6. Glyphosate, Hard Water and Nephrotoxic Metals: Are They the Culprits Behind the Epidemic of Chronic Kidney Disease of Unknown Etiology in Sri Lanka?

    Directory of Open Access Journals (Sweden)

    Channa Jayasumana

    2014-02-01

    Full Text Available The current chronic kidney disease epidemic, the major health issue in the rice paddy farming areas in Sri Lanka has been the subject of many scientific and political debates over the last decade. Although there is no agreement among scientists about the etiology of the disease, a majority of them has concluded that this is a toxic nephropathy. None of the hypotheses put forward so far could explain coherently the totality of clinical, biochemical, histopathological findings, and the unique geographical distribution of the disease and its appearance in the mid-1990s. A strong association between the consumption of hard water and the occurrence of this special kidney disease has been observed, but the relationship has not been explained consistently. Here, we have hypothesized the association of using glyphosate, the most widely used herbicide in the disease endemic area and its unique metal chelating properties. The possible role played by glyphosate-metal complexes in this epidemic has not been given any serious consideration by investigators for the last two decades. Furthermore, it may explain similar kidney disease epidemics observed in Andra Pradesh (India and Central America. Although glyphosate alone does not cause an epidemic of chronic kidney disease, it seems to have acquired the ability to destroy the renal tissues of thousands of farmers when it forms complexes with a localized geo environmental factor (hardness and nephrotoxic metals.

  7. Glyphosate, hard water and nephrotoxic metals: are they the culprits behind the epidemic of chronic kidney disease of unknown etiology in Sri Lanka?

    Science.gov (United States)

    Jayasumana, Channa; Gunatilake, Sarath; Senanayake, Priyantha

    2014-02-20

    The current chronic kidney disease epidemic, the major health issue in the rice paddy farming areas in Sri Lanka has been the subject of many scientific and political debates over the last decade. Although there is no agreement among scientists about the etiology of the disease, a majority of them has concluded that this is a toxic nephropathy. None of the hypotheses put forward so far could explain coherently the totality of clinical, biochemical, histopathological findings, and the unique geographical distribution of the disease and its appearance in the mid-1990s. A strong association between the consumption of hard water and the occurrence of this special kidney disease has been observed, but the relationship has not been explained consistently. Here, we have hypothesized the association of using glyphosate, the most widely used herbicide in the disease endemic area and its unique metal chelating properties. The possible role played by glyphosate-metal complexes in this epidemic has not been given any serious consideration by investigators for the last two decades. Furthermore, it may explain similar kidney disease epidemics observed in Andra Pradesh (India) and Central America. Although glyphosate alone does not cause an epidemic of chronic kidney disease, it seems to have acquired the ability to destroy the renal tissues of thousands of farmers when it forms complexes with a localized geo environmental factor (hardness) and nephrotoxic metals.

  8. Rainfall-driven epidemic cholera: hydrologic controls on water-borne disease and multi-season projections

    Science.gov (United States)

    Righetto, L.; Bertuzzo, E.; Mari, L.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2012-12-01

    Following the acknowledgement of a clear correlation between rainfall events and cholera resurgence, that was observed in Haiti starting from May 2011, we use a multi-variate Poisson generator to produce rainfall inputs, with which we force spatially explicit models of cholera spreading. Our models consist of ODE systems of equations, describing a network of human communities (divided in Susceptible, Infected and Recovered individuals) connected by river transport of pathogens and human mobility. We perform an a posteriori analysis -- from the beginning of the epidemic until December 2011 -- to assess the model reliability in predicting cholera cases and in testing control measures -- involving vaccination and sanitation campaigns. We then run a multi-seasonal prediction of the course of the epidemic until December 2015, to investigate further resurgences of cholera in the region and to evaluate, again, the effect of policies which may bring to the eradication of the disease in Haiti. We conclude that mathematical models may represent a key information tool for policy makers, as a way to preliminarly assess the possible future course of an epidemic and to test intervention policies to be deployed. Effect of intervention policies on the predicted course of the epidemic between 28/05-31/12/2011 (blue lines: simulations with the observed rainfall pattern; red lines/shaded range: median/25th-75th percentile range of simulations with generated rainfall). A) Effect of a reduction of the 20% of the contact rate , applied in one month starting from the 1st of June (dashed blue/red lines) or the 1st of July (dotted blue/red lines). B) A) Effect of a vaccination of 4 million individuals, implemented in one month starting from the 1st of June (dashed blue/red lines) or the 1st of July (dotted blue/red lines). C) Number of new cases in the period 28/05-31/12/2011 as a function of the reduction of the contact rate . D) Number of new cases in the period 28/05-31/12/2011 as a

  9. Coverage of the Ebola Virus Disease Epidemic in Three Widely Circulated United States Newspapers: Implications for Preparedness and Prevention

    Directory of Open Access Journals (Sweden)

    Corey H Basch

    2014-12-01

    Full Text Available Background:Widespread media attention about Ebola influences public aware-ness and interest, yet there is limited research on what aspects of Ebola have and have not been communicated through the media. Methods:We examined the nature and extent of coverage about Ebola in the three most widely circulated United States (U.S. daily newspapers. Between September 17, 2014 and October 17, 2014, 301 articles about Ebola in The New York Times, USA Today, and The Wall Street Journal were identified and cod-ed. Results:The most common topic was coverage of cases in the United States (39%, followed by the outbreak in Africa (33.6%. Conclusion:This is the first study to describe coverage of the Ebola epidemic in widely circulated U.S. newspapers. A substantial portion of the American public is concerned about being infected with Ebola virus disease (EVD. In this study, a large emphasis was placed on death tolls and the cases in the United States. Much more can be done to educate readers about relevant aspects of the Ebola epidemic, including how Ebola is and is not transmitted.

  10. Framing tropical disease in London: Patrick Manson, Filaria perstans, and the Uganda sleeping sickness epidemic, 1891-1902.

    Science.gov (United States)

    Haynes, D M

    2000-12-01

    Much of the historical literature on tropical medicine represents the periphery as the chief site for the production of western knowledge about disease in the British empire. This study on the Filaria perstans-sleeping sickness hypothesis revises this perspective by showing how the imperial metropole functioned as a culture space for the construction of knowledge about the empire. Beginning in 1891, Patrick Manson used the publicity resources of London to generate a rhetorical imperative for the confirmation of his hypothesis without ever leaving Britain. Later, while he was medical adviser to the imperial state, the 1900 sleeping sickness epidemic in Uganda presented Manson with a unique opportunity to determine the validity of his hypothesis. By exaggerating the possible spread of the epidemic privately among Foreign Office personnel and publicly in the medical press, he succeeded in mobilizing the first Royal Society sleeping sickness research expedition to Africa in 1902. While this expedition ultimately disproved Manson's hypothesis, this outcome ironically created the very conditions for the identification of the actual causal agent (Trypanosoma gambiense) and its vector (tsetse fly) by Aldo Castellani and David Bruce respectively.

  11. [The 2011 HUS epidemic in Germany. Challenges for disease control: what should be improved?].

    Science.gov (United States)

    Krause, G; Frank, C; Gilsdorf, A; Mielke, M; Schaade, L; Stark, K; Burger, R

    2013-01-01

    From May to July 2011 [corrected] the world's largest outbreak of hemolytic uremic syndrome (HUS) occurred in northern Germany with dramatic consequences for the population, the health care system and the food industry. In the following we examine the detection of the outbreak, epidemic management and related public communication aspects based on scientific publications, media reports as well as own and new data analyses. The subsequent 17 recommendations concern issues such as participation in and implementation of existing and new surveillance systems particularly with respect to physicians, broad application of finely tuned microbiological typing, improved personnel capacity and crisis management structures within the public health service and evidence-based communication by administrations and scientific associations. Outbreaks of similar dimensions can inevitably occur again and result in costs which will far exceed investments needed for early detection and control. This societal balance should be taken into account in spite of limited resources in the public health sector.

  12. Impact on Epidemic Measles of Vaccination Campaigns Triggered by Disease Outbreaks or Serosurveys: A Modeling Study.

    Science.gov (United States)

    Lessler, Justin; Metcalf, C Jessica E; Cutts, Felicity T; Grenfell, Bryan T

    2016-10-01

    Routine vaccination supplemented by planned campaigns occurring at 2-5 y intervals is the core of current measles control and elimination efforts. Yet, large, unexpected outbreaks still occur, even when control measures appear effective. Supplementing these activities with mass vaccination campaigns triggered when low levels of measles immunity are observed in a sample of the population (i.e., serosurveys) or incident measles cases occur may provide a way to limit the size of outbreaks. Measles incidence was simulated using stochastic age-structured epidemic models in settings conducive to high or low measles incidence, roughly reflecting demographic contexts and measles vaccination coverage of four heterogeneous countries: Nepal, Niger, Yemen, and Zambia. Uncertainty in underlying vaccination rates was modeled. Scenarios with case- or serosurvey-triggered campaigns reaching 20% of the susceptible population were compared to scenarios without triggered campaigns. The best performing of the tested case-triggered campaigns prevent an average of 28,613 (95% CI 25,722-31,505) cases over 15 y in our highest incidence setting and 599 (95% CI 464-735) cases in the lowest incidence setting. Serosurvey-triggered campaigns can prevent 89,173 (95% CI, 86,768-91,577) and 744 (612-876) cases, respectively, but are triggered yearly in high-incidence settings. Triggered campaigns reduce the highest cumulative incidence seen in simulations by up to 80%. While the scenarios considered in this strategic modeling exercise are reflective of real populations, the exact quantitative interpretation of the results is limited by the simplifications in country structure, vaccination policy, and surveillance system performance. Careful investigation into the cost-effectiveness in different contexts would be essential before moving forward with implementation. Serologically triggered campaigns could help prevent severe epidemics in the face of epidemiological and vaccination uncertainty

  13. 羊场主要流行疫病调查%Major Epidemic Diseases Investigation at Sheep Farm

    Institute of Scientific and Technical Information of China (English)

    颜艾; 王开功; 文明; 周碧君; 程振涛; 岳筠; 李敬丹; 隆华; 周珊珊

    2011-01-01

    本试验旨在了解贵州省规模化养羊场、种羊场、散养户的主要疫病流行病学动态,疫苗免疫状态、疫病控制效果等,以期为羊群疫病的防控决策提供科学依据.于2007-2010年对贵州省A、B、C、D、E、F、G、H、I 9个地(州市)部分规模化羊场、种羊场和散养户进行了羊主要疫病流行病学调查和病原学检测.结果显示,9个地州市羊口蹄疫O型、口蹄疫亚洲Ⅰ型、口蹄疫隐性感染、布鲁氏杆菌病、山羊痘,平均阳性率分别为58.85%、47.83%、10.39%、7.67%、90.00%;同时在发病羊中检出山羊痘、羔羊大肠杆菌病、葡萄球菌病,多种寄生虫混合感染,羊传染性胸膜肺炎等.以上数据表明在部分养殖场中虽加强免疫防控,但抗体效价仍较低,且细菌性疾病混合感染普遍存在,成为羊病防疫中不可忽视的一个环节.%For understanding epidemics dynamic,vaccine immune status and disease control effect of the scale goats farm, the breeding goat farm and free-range raising farm. We do major epidemiologically investigate and etiologically detect for epidemic disease in the Zunyi,Liupanshui,Bijie southeast of the Guizhou province from 2007 to 2010. Providing a evidence for the next step of flocks epidemics counter-measures decision-making. The result showed that the average antibody positive rate of FMD type I , FMD type O.inapparent infection of FMD, Brucella, and GPV was 58. 85%, 47. 83%, 10. 39%, 7. 67%, 90. 00% in the nine districts; contemporary we detected the GPV,lamb colibacillosis,Staphylococcus aureus disease and mange mite disease etc,above data showed that although strengthen the immune antibody titer prevention and control,but is still low, and mixed infection bacterial disease common see,that become the a link cannot be neglected in goats epidemic prevention.

  14. Epidemiology of the Foot-and-Mouth Disease Serotype O Epidemic of November 2010 to April 2011 in the Republic Of Korea.

    Science.gov (United States)

    Yoon, H; Yoon, S-S; Kim, Y-J; Moon, O-K; Wee, S-H; Joo, Y-S; Kim, B

    2015-06-01

    The largest epidemic of foot-and-mouth disease (FMD) in Korea since the first record in 1911 occurred between November 2010 and April 2011. The outbreak was confirmed in 153 farms, and more than three million animals were destroyed. This study presents the temporal and spatial distribution patterns, epidemiological investigation and the control measures for the 2010/2011 epidemic in Korea. The index case of this 2010/2011 FMD epidemic was reported in a pig-farming complex with five piggeries in Andong, GyeongBuk Province, on 28 November 2010, and the outbreak lasted 145 days. The largest number of new detection of the infected farms per day was recorded in mid-January. Epidemiological investigation revealed that the FMD virus had spread from farm to farm through routine movements associated with animal husbandry operations. In contrast to FMD epidemics in other countries in which movement of the infected animals largely contributed to the spread of the disease, human behaviours were major factors in the spread of the FMD virus in the Korean epidemic. The 2010/2011 epidemic was first confirmed in a local small and medium city where share of smallholder producers is higher than that of other provinces. Although Korea had a well-developed emergent response system with the experience of controlling infection and re-obtaining FMD-free status after the previous epidemics, Korea was prompted to revise their contingency plan by tailoring it to its unique livestock environment. Practical contingency plans tailored to Korea for control of FMD can be fully effective when farmers, livestock-related agencies, veterinary service providers and the general public work together.

  15. Potential risk associated with animal culling and disposal during the foot-and-mouth disease epidemic in Japan in 2010.

    Science.gov (United States)

    Hayama, Yoko; Kimura, Yoshinari; Yamamoto, Takehisa; Kobayashi, Sota; Tsutsui, Toshiyuki

    2015-10-01

    The large-scale foot-and-mouth (FMD) outbreak in 2010 in Japan presented logistical challenges in conducting animal culling and disposal. During the epidemic, culling of animals on infected farms was delayed owing to the difficulties in finding suitable burial sites. In this study, a retrospective matched case-control study was conducted to investigate the potential transmission risk associated with carcass disposal by considering the geographical relationship between farms and burial sites. The results showed that burial sites and transportation routes used for carcass disposal were not significant infection sources to the neighboring farms. However, infectious farms within 500 m, particularly, pig infected farms, posed a significant transmission risk to the neighboring farms. Implementation of strict bio-security measures during carcass disposal operation is essential to reduce the risk of disease transmission to neighboring farms.

  16. Impact on Epidemic Measles of Vaccination Campaigns Triggered by Disease Outbreaks or Serosurveys: A Modeling Study

    Science.gov (United States)

    Metcalf, C. Jessica E.; Cutts, Felicity T.; Grenfell, Bryan T.

    2016-01-01

    Background Routine vaccination supplemented by planned campaigns occurring at 2–5 y intervals is the core of current measles control and elimination efforts. Yet, large, unexpected outbreaks still occur, even when control measures appear effective. Supplementing these activities with mass vaccination campaigns triggered when low levels of measles immunity are observed in a sample of the population (i.e., serosurveys) or incident measles cases occur may provide a way to limit the size of outbreaks. Methods and Findings Measles incidence was simulated using stochastic age-structured epidemic models in settings conducive to high or low measles incidence, roughly reflecting demographic contexts and measles vaccination coverage of four heterogeneous countries: Nepal, Niger, Yemen, and Zambia. Uncertainty in underlying vaccination rates was modeled. Scenarios with case- or serosurvey-triggered campaigns reaching 20% of the susceptible population were compared to scenarios without triggered campaigns. The best performing of the tested case-triggered campaigns prevent an average of 28,613 (95% CI 25,722–31,505) cases over 15 y in our highest incidence setting and 599 (95% CI 464–735) cases in the lowest incidence setting. Serosurvey-triggered campaigns can prevent 89,173 (95% CI, 86,768–91,577) and 744 (612–876) cases, respectively, but are triggered yearly in high-incidence settings. Triggered campaigns reduce the highest cumulative incidence seen in simulations by up to 80%. While the scenarios considered in this strategic modeling exercise are reflective of real populations, the exact quantitative interpretation of the results is limited by the simplifications in country structure, vaccination policy, and surveillance system performance. Careful investigation into the cost-effectiveness in different contexts would be essential before moving forward with implementation. Conclusions Serologically triggered campaigns could help prevent severe epidemics in the

  17. [Epidemic trend on notifiable communicable diseases from 2010 to 2015 in Beijing].

    Science.gov (United States)

    Gao, J H; Huang, R G

    2016-06-01

    To analyze the trends and epidemiological characteristics of notifiable communicable diseases from 2010 to 2015 in Beijing so as to provide reliable reference data. Data on the epidemiological characteristics was gathered and analyzed through the monitoring programs on notifiable diseases, reported by the China Information System for Disease Control and Prevention, from 2010 to 2015. A total of 764 290 cases of notifiable communicable diseases were reported from 2010 to 2015 in Beijing. The annual reported incidence on notifiable communicable diseases showed an annual downward (χ(2)=1.25×10(4), Pdiseases and respiratory infectious diseases also showed an annual downward (χ(2)=1.25×10(4), Pchildren under 7 years old appeared higher than that of the other age groups that accounted for 47.79% of the total reported cases. High incidence mainly appeared in children that living scattering around which accounted for 31.64% of the total reported cases. The first three leading incidence rates seen in other infectious diseases were infectious diarrhea, hand-foot-and-mouth disease and dysentery for the last consecutive 6 years. The laboratory diagnosed rate on notifiable disease was 16.67%, but with a trend of annual increase. Intestinal infective diseases kept the highest incidence among all the notifiable communicable diseases, suggesting the necessity of improving the prevention and control programs on notifiable communicable diseases in preschool, especially in those children with their houses scattered around. Programs on laboratory diagnosis also need to be strengthened.

  18. Children's Participation in a Virtual Epidemic in the Science Classroom: Making Connections to Natural Infectious Diseases

    Science.gov (United States)

    Neulight, Nina; Kafai, Yasmin B.; Kao, Linda; Foley, Brian; Galas, Cathleen

    2007-01-01

    This study investigated students' understanding of a virtual infectious disease in relation to their understanding of natural infectious diseases. Two sixth-grade classrooms of students between the ages of 10 and 12 (46 students) took part in a participatory simulation of a virtual infectious disease, which was integrated into their science…

  19. Children's Participation in a Virtual Epidemic in the Science Classroom: Making Connections to Natural Infectious Diseases

    Science.gov (United States)

    Neulight, Nina; Kafai, Yasmin B.; Kao, Linda; Foley, Brian; Galas, Cathleen

    2007-01-01

    This study investigated students' understanding of a virtual infectious disease in relation to their understanding of natural infectious diseases. Two sixth-grade classrooms of students between the ages of 10 and 12 (46 students) took part in a participatory simulation of a virtual infectious disease, which was integrated into their science…

  20. Distribution of cow-calf producers' beliefs about reporting cattle with clinical signs of foot-and-mouth disease to a veterinarian before or during a hypothetical outbreak.

    Science.gov (United States)

    Delgado, Amy H; Norby, Bo; Scott, H Morgan; Dean, Wesley; McIntosh, W Alex; Bush, Eric

    2014-12-01

    Understanding the prevalence of cattle producers' beliefs regarding disease reporting can help officials improve surveillance programs with passive data collection. A cross-sectional survey was conducted in Texas in 2008 and 2009 to determine beliefs about reporting cattle with clinical signs consistent with foot-and-mouth disease (FMD) either prior to (scenario 1) or during an on-going outbreak of FMD (scenario 2). Two questionnaires were developed and distributed to Texas cow-calf producers in order to evaluate their behavioral, control, and normative beliefs related to disease reporting. The context for each behavior was provided through the use of scenarios, and belief strength was measured using a 7-point Likert-like scale. Beliefs were compared across scenarios and demographic categories, and the effect of scenario on belief examined using ordinal logistic regression. Respondents agreed that reporting clinically suspect cases would have positive economic and emotional consequences; however, when an outbreak was known to be present, producers were less likely to agree with many of the positive outcomes of reporting. Important barriers to disease reporting indicated by producers included a lack of knowledge related to clinical signs of highly contagious cattle diseases and which cattle are at risk of contracting FMD. In general, beliefs about barriers to reporting did not differ based on scenario. Veterinarians and regulatory authorities were the groups perceived to most strongly expect disease reporting, regardless of the scenario. Risk education for producers related to clinical signs of reportable livestock diseases, post-reporting procedures, and an understanding of FMD introduction and spread may improve the reporting of cattle with clinical signs consistent with FMD. Published by Elsevier B.V.

  1. Infectious diseases epidemic threats and mass gatherings: Refocusing global attention on the continuing spread of the Middle East Respiratory syndrome coronavirus (MERS-CoV)

    NARCIS (Netherlands)

    Zumla, A. (Alimuddin); Alagaili, A.N. (Abdulaziz N.); Cotten, M. (Matthew); Azhar, E.I. (Esam I.)

    2016-01-01

    textabstractMedia and World Health Organization (WHO) attention on Zika virus transmission at the 2016 Rio Olympic Games and the 2015 Ebola virus outbreak in West Africa diverted the attention of global public health authorities from other lethal infectious diseases with epidemic potential. Mass

  2. Infectious diseases epidemic threats and mass gatherings: Refocusing global attention on the continuing spread of the Middle East Respiratory syndrome coronavirus (MERS-CoV)

    NARCIS (Netherlands)

    Zumla, A. (Alimuddin); Alagaili, A.N. (Abdulaziz N.); Cotten, M. (Matthew); Azhar, E.I. (Esam I.)

    2016-01-01

    textabstractMedia and World Health Organization (WHO) attention on Zika virus transmission at the 2016 Rio Olympic Games and the 2015 Ebola virus outbreak in West Africa diverted the attention of global public health authorities from other lethal infectious diseases with epidemic potential. Mass gat

  3. Infectious diseases epidemic threats and mass gatherings: Refocusing global attention on the continuing spread of the Middle East Respiratory syndrome coronavirus (MERS-CoV)

    NARCIS (Netherlands)

    Zumla, A. (Alimuddin); Alagaili, A.N. (Abdulaziz N.); Cotten, M. (Matthew); Azhar, E.I. (Esam I.)

    2016-01-01

    textabstractMedia and World Health Organization (WHO) attention on Zika virus transmission at the 2016 Rio Olympic Games and the 2015 Ebola virus outbreak in West Africa diverted the attention of global public health authorities from other lethal infectious diseases with epidemic potential. Mass gat

  4. Impact of infectious disease epidemics on tuberculosis diagnostic, management, and prevention services: experiences and lessons from the 2014–2015 Ebola virus disease outbreak in West Africa

    Directory of Open Access Journals (Sweden)

    Rashid Ansumana

    2017-03-01

    Full Text Available The World Health Organization (WHO Global Tuberculosis Report 2015 states that 28% of the world's 9.6 million new tuberculosis (TB cases are in the WHO Africa Region. The Mano River Union (MRU countries of West Africa–Guinea, Sierra Leone, and Liberia–have made incremental sustained investments into TB control programmes over the past two decades. The devastating Ebola virus disease (EVD outbreak of 2014–2015 in West Africa impacted significantly on all sectors of the healthcare systems in the MRU countries, including the TB prevention and control programmes. The EVD outbreak also had an adverse impact on the healthcare workforce and healthcare service delivery. At the height of the EVD outbreak, numerous staff members in all MRU countries contracted EBV at the Ebola treatment units and died. Many healthcare workers were also infected in healthcare facilities that were not Ebola treatment units but were national hospitals and peripheral health units that were unprepared for receiving patients with EVD. In all three MRU countries, the disruption to TB services due to the EVD epidemic will no doubt have increased Mycobacterium tuberculosis transmission, TB morbidity and mortality, and decreased patient adherence to TB treatment, and the likely impact will not be known for several years to come. In this viewpoint, the impact that the EVD outbreak had on TB diagnostic, management, and prevention services is described. Vaccination against TB with BCG in children under 5 years of age was affected adversely by the EVD epidemic. The EVD outbreak was a result of global failure and represents yet another ‘wake-up call’ to the international community, and particularly to African governments, to reach a consensus on new ways of thinking at the national, regional, and global levels for building healthcare systems that can sustain their function during outbreaks. This is necessary so that other disease control programmes (like those for TB, malaria

  5. Hand, Foot, and Mouth Disease in China: Modeling Epidemic Dynamics of Enterovirus Serotypes and Implications for Vaccination.

    Directory of Open Access Journals (Sweden)

    Saki Takahashi

    2016-02-01

    Full Text Available Hand, foot, and mouth disease (HFMD is a common childhood illness caused by serotypes of the Enterovirus A species in the genus Enterovirus of the Picornaviridae family. The disease has had a substantial burden throughout East and Southeast Asia over the past 15 y. China reported 9 million cases of HFMD between 2008 and 2013, with the two serotypes Enterovirus A71 (EV-A71 and Coxsackievirus A16 (CV-A16 being responsible for the majority of these cases. Three recent phase 3 clinical trials showed that inactivated monovalent EV-A71 vaccines manufactured in China were highly efficacious against HFMD associated with EV-A71, but offered no protection against HFMD caused by CV-A16. To better inform vaccination policy, we used mathematical models to evaluate the effect of prospective vaccination against EV-A71-associated HFMD and the potential risk of serotype replacement by CV-A16. We also extended the model to address the co-circulation, and implications for vaccination, of additional non-EV-A71, non-CV-A16 serotypes of enterovirus.Weekly reports of HFMD incidence from 31 provinces in Mainland China from 1 January 2009 to 31 December 2013 were used to fit multi-serotype time series susceptible-infected-recovered (TSIR epidemic models. We obtained good model fit for the two-serotype TSIR with cross-protection, capturing the seasonality and geographic heterogeneity of province-level transmission, with strong correlation between the observed and simulated epidemic series. The national estimate of the basic reproduction number, R0, weighted by provincial population size, was 26.63 for EV-A71 (interquartile range [IQR]: 23.14, 30.40 and 27.13 for CV-A16 (IQR: 23.15, 31.34, with considerable variation between provinces (however, predictions about the overall impact of vaccination were robust to this variation. EV-A71 incidence was projected to decrease monotonically with higher coverage rates of EV-A71 vaccination. Across provinces, CV-A16 incidence in the

  6. Non-alcoholic fatty liver disease: a new epidemic in children.

    Science.gov (United States)

    Ciocca, Mirta; Ramonet, Margarita; Álvarez, Fernando

    2016-12-01

    Non-alcoholic fatty liver disease is considered one of the most common causes of liver disease in adults and children, consistent with the increased prevalence of obesity in both populations worldwide. It is a multifactorial condition involving a broad spectrum of liver diseases than range from simple steatosis to steatohepatitis, and characterized by histological findings of inflammation and fibrosis. Its pathogenesis and progression are not fully understood yet, and a more complete understanding of liver disease may aid in developing new therapies and noninvasive diagnostic tools. Liver biopsy remains the gold standard for disease staging. Although lifestyle and diet modifications are the keys in non-alcoholic fatty liver disease treatment, the development of new drugs may be promising for patients failing first-line therapy.

  7. Insights in public health: The hidden epidemic: sexually transmitted diseases in 2014.

    Science.gov (United States)

    Katz, Alan R

    2014-08-01

    Diseases caused by sexually transmitted agents are among the most common infectious diseases in the United States. Sexually transmitted diseases (STDs) have serious sequelae including physical pain, emotional distress, adverse reproductive outcomes, and cancer. They also pose an economic burden on society. STDs are challenging to prevent and control due to a general reluctance to address sexual health issues in an open manner. Human papillomavirus infection, chlamydia, and gonorrhea have recently been addressed by the Centers for Disease Control and Prevention in their Grand Rounds series reflecting their high-profile status on the national prevention and control agenda. This Insights column will focus on these three STDs.

  8. Analysis of factors associated with hesitation to restart farming after depopulation of animals due to 2010 foot-and-mouth disease epidemic in Japan

    Science.gov (United States)

    KADOWAKI, Hazumu; KAYANO, Taishi; TOBINAGA, Takaharu; TSUTSUMI, Atsuro; WATARI, Michiko; MAKITA, Kohei

    2016-01-01

    An outbreak of foot-and-mouth disease (FMD) occurred in Miyazaki Prefecture, Japan, in 2010. This epidemic was controlled with culling and vaccination, and resulted in the death of nearly 290,000 animals. This paper describes the factors associated with hesitation to restart farming after the epidemic. A questionnaire survey was conducted to assess the mental health of farmers one year after the end of the FMD epidemic in affected areas, and univariate and multivariable analyses were performed. Of 773 farms which had answered the question about restart farming, 55.4% (428/773) had resumed or were planning to resume operation. The farms hesitated restarting were characterized by small scale (P=0.06) and having multiple sources of income (P<0.01). Personal attributes associated with hesitation to restart were advanced age of the owner (P<0.01), with someone with bad physical conditions (P=0.04) and small family size (P<0.01). Factors related to disease control during the epidemic that were associated with hesitation to restart were vaccination of animals (P<0.01), not assisting with culling on other farms (P<0.01), and higher satisfaction with information provided by the government (P=0.02). We found that farmers hesitated to resume farming because they had a limited labor force, had an alternative business or were mentally distressed during disease control. PMID:27149890

  9. Viral meningitis epidemics and a single, recent, recombinant and anthroponotic origin of swine vesicular disease virus

    DEFF Research Database (Denmark)

    Bruhn, Christian Anders Wathne; Nielsen, Sandra Cathrine Abel; Samaniego Castruita, Jose Alfredo

    2015-01-01

    BACKGROUND AND OBJECTIVES: Swine vesicular disease virus (SVDV) is a close relative of the human Enterovirus B serotype, coxsackievirus B5. As the etiological agent of a significant emergent veterinary disease, several studies have attempted to explain its origin. However, several key questions...

  10. Investigation of airborne foot-and-mouth disease virus transmission during low-wind conditions in the early phase of the UK 2001 epidemic

    DEFF Research Database (Denmark)

    Mikkelsen, T.; Alexandersen, S.; Astrup, P.;

    2003-01-01

    animals. Such spread can be rapid and extensive, and it is known in certain circumstances to have transmitted disease over a distance of several hundred kilometres. During the 2001 FMD epidemic in the United Kingdom (UK), atmospheric dispersion models were applied in real time in order to assess...... techniques and presents the results obtained of detailed analyses performed during the early stages of the UK 2001 epidemic. This paper investigates the potential for disease spread in relation to two outbreaks (Burnside Farm, Heddon-on-the-Wall and Prestwick Hall Farm, Ponteland, Northumberland). A separate...... paper (Gloster et al., 2002) provides a more detailed analysis of the airborne disease transmission in the vicinity of Burnside Farm. The combined results are consistent with airborne transmission of disease to livestock in the Heddon-on-the-Wall area. Local topography may have played a significant role...

  11. Investigation of airborne foot-and-mouth disease virus transmission during low-wind conditions in the early phase of the UK 2001 epidemic

    DEFF Research Database (Denmark)

    Mikkelsen, T.; Alexandersen, S.; Astrup, P.;

    2003-01-01

    animals. Such spread can be rapid and extensive, and it is known in certain circumstances to have transmitted disease over a distance of several hundred kilometres. During the 2001 FMD epidemic in the United Kingdom (UK), atmospheric dispersion models were applied in real time in order to assess...... techniques and presents the results obtained of detailed analyses performed during the early stages of the UK 2001 epidemic. This paper investigates the potential for disease spread in relation to two outbreaks (Burnside Farm, Heddon-on-the-Wall and Prestwick Hall Farm, Ponteland, Northumberland). A separate...... paper (Gloster et al., 2002) provides a more detailed analysis of the airborne disease transmission in the vicinity of Burnside Farm. The combined results are consistent with airborne transmission of disease to live stock in the Heddon-on-the Wall area. Local topography may have played a significant...

  12. Nutritional and food protection against epidemic emerging neuropathy. Epidemiological findings in the unique disease-free urban area of Cuba.

    Science.gov (United States)

    Barnouin, J; Verdura Barrios, T; Chassagne, M; Pérez Cristiá, R; Arnaud, J; Fleites Mestre, P; Montoya, M E; Favier, A

    2001-09-01

    A survey was conducted through the SECUBA (SEguridad alimentaria en CUba y Buena Alimentación) research program in Cuban healthy smokers living in Guantánamo and in Havana. The aim of the survey was to investigate biological and nutritional factors connected with the occurrence of zero epidemic neuropathy (EN) observed in Guantánamo urban area since the disease emerged in Cuba. Blood riboflavin status and carotenoid and selenium concentrations were higher in Guantánamo than in Havana smokers. Food dietary quantities of plantain banana, pepper (Capsicum spp.), bovine meat and milk products were higher in Guantánamo. Inversely, foods rich in cholesterol, especially eggs, were more consumed in Havana. Through riboflavin, carotenoid and selenium contents and specific antioxidants substances (indoleamines, capsaicin), the foods more consumed in Guantánamo could be considered as EN protective factors. Disease protective effects could be exerted via enhancement of defence mechanisms against free radical damage and related mechanisms focused on redox recycling of glutathione and local protection from carotenoids. Finally, the results of the present study should help Cuba, through a better EN control, to improve long-term food safety and define healthier dietary habits.

  13. Predicting distribution of Aedes aegypti and Culex pipiens complex, potential vectors of Rift Valley fever virus in relation to disease epidemics in East Africa

    Directory of Open Access Journals (Sweden)

    Clement Nyamunura Mweya

    2013-10-01

    Full Text Available Background: The East African region has experienced several Rift Valley fever (RVF outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. Methods: Diverse ecological niche modelling techniques have been developed for this purpose: we present a maximum entropy (Maxent approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Results: Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Conclusion: Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods.

  14. Epidemic of Chronic Kidney Disease in India -What Can Be Done?

    Directory of Open Access Journals (Sweden)

    Prabahar Murugesan

    2008-01-01

    Full Text Available The exact prevalence of chronic kidney disease in India is not clear in the absence of regular national registry data and provided only by small observational series or rely on reports from personal experience, but the quality of data is quiet uneven. There are only three population based studies in India commenting on the magnitude of chronic kidney disease. In a prevention program started at community level in Chennai, the reported prevalence is 0.86% in the project population and 1.39% in the control region. The second study is based on Delhi involving 4972 urban patients. The prevalence of chronic renal failure (defined as serum creatinine more than 1.8 mg/dL to be 0.79 % or 7852 per million/population. The third study perhaps the only longitudinal study to identify the incidence of end stage renal disease is based on 572,029 subjects residing in city of Bhopal suggests that the average crude and age adjusted incidence rates of end stage renal disease were 151 and 232 per million population respectively. The resources and skill for taking care of this large case load, both in terms of personal and health care infrastructure do not exist currently and would need to be created. To tackle the problem of limited access to renal replacement therapy, an important method would be to try and reduce the incidence of end stage renal disease and the need of renal replacement therapy by preventive measures. It is clear that treatment of chronic kidney disease and its advanced stage end stage renal disease is expensive and beyond the reach of average Indian. Thus it is crucial that prevention of chronic kidney disease has to be the goal of medical fraternity, government of India and the general public. This article suggests a series of primary, secondary and tertiary preventive measures for prevention of chronic kidney disease. Clearly there are already many effective and attractive interventions for the treatment and prevention of chronic kidney disease

  15. Epidemics of emerging animal diseases and food-borne infection problems over the last 5 years in Japan.

    Science.gov (United States)

    Yamane, Itsuro

    2006-10-01

    There have been several emerging animal diseases and food-borne infection problems occurring in Japan over the last 5 years. We describe brief pictures of these epidemics and our control activities. As acute contagious and/or emerging animal diseases, the foot and mouth disease (FMD) outbreak caused by the Pan-Asian topotype of the type O virus occurred in March 2000 after 92 years of FMD-free status. In 2004, four cases of the highly pathogenic avian influenza (HPAI), which was the first outbreak after 79 years, and caused by the H5N1 subtype, were identified. As part of the responses against these outbreaks, all the animals in the affected farms were destroyed, and movement control areas were established around the infected premises, and a nation-wide intensive survey for FMD and HPAI was performed. As for food-borne or feed-borne infections, the first bovine spongiform encephalopathy (BSE) was identified in September 2001 and 19 more cases have been reported until June 2005. A large outbreak of food-borne infection caused by low-fat milk contaminated with enterotoxin A produced by Staphylococcus aureus, involving more than 13,000 patients, occurred in 2000. In 2003, people who consumed uncooked liver and meat from wild boar and deer developed clinical signs of hepatitis caused by the hepatitis E virus. Pork is also suspected as natural source of virus transmission. Early detection of the first cases and rapid action in preventing and controlling the spread of infections are very important combined with proper risk communication about correct information of the diseases.

  16. The Obesity Epidemic

    Centers for Disease Control (CDC) Podcasts

    2011-07-18

    Learn about obesity and the community initiatives taking place to prevent and reduce this epidemic.  Created: 7/18/2011 by National Center for Chronic Disease Prevention and Health Promotion, Division of Nutrition, Physical Activity and Obesity.   Date Released: 7/18/2011.

  17. 中医温病诊疗知识模型初探%Preliminary Study on Knowledge Model on Diagnosis and Treatment of Epidemic Febrile Disease in TCM

    Institute of Scientific and Technical Information of China (English)

    于琦; 杨阳; 李敬华; 朱晓博; 王静; 张晶; 奚怀平; 崔蒙; 李园白; 宓金华; 梁欣颖; 朱玲; 刘丽红; 田野

    2012-01-01

    Objective To establish knowledge model on diagnosis and treatment of epidemic febrile disease in TCM, comb epidemic febrile disease literature knowledge and assist clinical decision of febrile disease. Methods The model was established based on ontology, the rational knowledge representation methods, OWL2 ontology language for modeling tools. Results More reasonable and clearer hierarchy structure epidemic febrile disease clinics knowledge model was established by combing concept relations of epidemic febrile disease, establishing equivalence class and contacting information of the parent-child relationship. The function of the model on learning and reasoning was realized by machine learning and inference engine, which could provide clinicians with a literature reference. Conclusion This study established the knowledge model of diagnosis and treatment of epidemic febrile disease, and realized the epidemic febrile disease clinical decision support, which provides a kind of effective way of knowledge organization on TCM literature assist TCM clinical decision-making.%目的 建立温病诊疗知识模型,梳理温病文献知识,辅助中医温病临床决策.方法 从中医温病学入手,以本体论为基础,采用合理的知识表示方式,以OWL2本体语言为建模工具,进行模型构建的探索研究.结果 通过梳理温病诊疗概念关系,建立等价类和父子关系的联系方式,初步建立层次较清楚、结构较为合理的中医温病诊疗知识模型;通过机器学习和推理机,实现模型学习推理的功能,为临床医生提供文献参考.结论 本研究初步建立了中医温病诊疗知识模型,并实现辅助中医温病临床决策,为中医文献支持中医临床决策提供了一种有效的知识组织方式.

  18. Pin1, a new player in the fate of HIF-1α degradation: an hypothetical mechanism inside vascular damage as Alzheimer’s disease risk factor.

    Directory of Open Access Journals (Sweden)

    Elena eLonati

    2014-01-01

    Full Text Available Aetiology of neurodegenerative mechanisms underlying Alzheimer's disease (AD are still under elucidation. The contribution of cerebrovascular deficiencies (such as cerebral ischemia/stroke has been strongly endorsed in recent years. Reduction of blood supply leading to hypoxic condition is known to activate cellular responses mainly controlled by hypoxia-inducible transcription factor-1 (HIF-1. Thus alterations of oxygen responsive HIF-1α subunit in the central nervous system may contribute to the cognitive decline, especially influencing mechanisms associated to APP (amyloid precursor protein amyloidogenic metabolism. Although HIF-1α protein level is known to be regulated by von Hippel-Lindau (VHL ubiquitin-proteasome system, it has been recently suggested that Gsk-3β (glycogen synthase kinase-3β promotes a VHL-independent HIF-1α degradation. Here we provide evidences that in rat primary hippocampal cell cultures, HIF-1α degradation might be mediated by a synergic action of Gsk-3β and Pin1 (peptidyl-prolyl cis/trans isomerase. In post-ischemic conditions, such as those mimicked with oxygen glucose deprivation (OGD, HIF-1α protein level increases remaining unexpectedly high for long time after normal condition restoration jointly with the increase of LDH (lactate dehydrogenase and BACE1 (β-secretase 1 protein expression (70% and 140% respectively. Interestingly the Pin1 activity decreases about 40%-60% and Pin1S16 inhibitory phosphorylation significantly increases, indicating that Pin1 binding to its substrate and enzymatic activity are reduced by treatment. Co-immunoprecipitation experiments demonstrate that HIF-1α/Pin1 in normoxia are associated, and that in presence of specific Pin1 and Gsk-3β inhibitors their interaction is reduced in parallel to an increase of HIF-1α protein level. Thus we suggest that in post-OGD neurons the high level of HIF-1α might be due to Pin1 binding ability and activity reduction which affects HIF-1

  19. Economics of eradicating Foot-and-Mouth disease epidemics with alternative control strategies

    NARCIS (Netherlands)

    Bergevoet, R.H.M.; Asseldonk, van M.A.P.M.

    2014-01-01

    The paper presents an economic analysis of Foot-and-Mouth Disease (FMD) control strategies for livestock herds. Alternative vaccination-to-live control strategies were compared to the strategy that involves culling of all susceptible animals in an area of 1 km around infected herds in addition to

  20. Surveillance of emerging diseases in cattle : Application to the Schmallenberg virus epidemic in the Netherlands

    NARCIS (Netherlands)

    Veldhuis, A.M.B.

    2016-01-01

    Animal health surveillance is an essential component to protect animal health, facilitate trade, and protect public health. Reliable surveillance systems are able to rapidly identify outbreaks of emerging animal diseases in previously free areas to enable the implementation of control measures. In

  1. Modelling diseases with relapse and nonlinear incidence of infection: a multi-group epidemic model

    Science.gov (United States)

    Wang, Jinliang; Pang, Jingmei; Liu, Xianning

    2014-01-01

    In this paper, we introduce a basic reproduction number for a multi-group SIR model with general relapse distribution and nonlinear incidence rate. We find that basic reproduction number plays the role of a key threshold in establishing the global dynamics of the model. By means of appropriate Lyapunov functionals, a subtle grouping technique in estimating the derivatives of Lyapunov functionals guided by graph-theoretical approach and LaSalle invariance principle, it is proven that if it is less than or equal to one, the disease-free equilibrium is globally stable and the disease dies out; whereas if it is larger than one, some sufficient condition is obtained in ensuring that there is a unique endemic equilibrium which is globally stable and thus the disease persists in the population. Furthermore, our results suggest that general relapse distribution are not the reason of sustained oscillations. Biologically, our model might be realistic for sexually transmitted diseases, such as Herpes, Condyloma acuminatum, etc. PMID:24963980

  2. Modelling diseases with relapse and nonlinear incidence of infection: a multi-group epidemic model.

    Science.gov (United States)

    Wang, Jinliang; Pang, Jingmei; Liu, Xianning

    2014-01-01

    In this paper, we introduce a basic reproduction number for a multi-group SIR model with general relapse distribution and nonlinear incidence rate. We find that basic reproduction number plays the role of a key threshold in establishing the global dynamics of the model. By means of appropriate Lyapunov functionals, a subtle grouping technique in estimating the derivatives of Lyapunov functionals guided by graph-theoretical approach and LaSalle invariance principle, it is proven that if it is less than or equal to one, the disease-free equilibrium is globally stable and the disease dies out; whereas if it is larger than one, some sufficient condition is obtained in ensuring that there is a unique endemic equilibrium which is globally stable and thus the disease persists in the population. Furthermore, our results suggest that general relapse distribution are not the reason of sustained oscillations. Biologically, our model might be realistic for sexually transmitted diseases, such as Herpes, Condyloma acuminatum, etc.

  3. Economics of eradicating Foot-and-Mouth disease epidemics with alternative control strategies

    NARCIS (Netherlands)

    Bergevoet, R.H.M.; Asseldonk, van M.A.P.M.

    2014-01-01

    The paper presents an economic analysis of Foot-and-Mouth Disease (FMD) control strategies for livestock herds. Alternative vaccination-to-live control strategies were compared to the strategy that involves culling of all susceptible animals in an area of 1 km around infected herds in addition to st

  4. Dialysis enrollment patterns in Guatemala: evidence of the chronic kidney disease of non-traditional causes epidemic in Mesoamerica.

    Science.gov (United States)

    Laux, Timothy S; Barnoya, Joaquin; Guerrero, Douglas R; Rothstein, Marcos

    2015-04-14

    In western Nicaragua and El Salvador, chronic kidney disease (CKD) is highly prevalent and generally affects young, male, agricultural (usually sugar cane) workers without the established CKD risk factors. It is yet unknown if the prevalence of this CKD of Non-Traditional causes (CKDnT) extends to the northernmost Central American country, Guatemala. Therefore, we sought to compare dialysis enrollment rates by region, municipality, sex, daily temperature, and agricultural production in Guatemala and assess if there is a similar CKDnT distribution pattern as in Nicaragua and El Salvador. The National Center for Chronic Kidney Disease Treatment (Unidad Nacional de Atención al Enfermo Renal Crónico) is the largest provider of dialysis in Guatemala. We used population, Human Development Index, literacy, and agricultural databases to assess the geographic, economic, and educational correlations with the National Center for Chronic Kidney Disease Treatment's hemodialysis and peritoneal dialysis enrollment database. Enrollment rates (per 100 000) inhabitants were compared by region and mapped for comparison to regional agricultural and daytime temperature data. The distribution of men and women enrolled in dialysis were compared by region using Fisher's exact tests. Spearman's rank correlation coefficients were calculated. Dialysis enrollment is higher in the Southwest compared to the rest of the country where enrollees are more likely (p < 0.01) to be male (57.8%) compared to the rest of the country (49.3%). Dialysis enrollment positively correlates with Human Development Index and literacy rates. These correlations are weaker in the agricultural regions (predominantly sugar cane) of Southwest Guatemala. In Guatemala, CKDnT incidence may have a similar geographic distribution as Nicaragua and El Salvador (higher in the high temperature and sugar cane growing regions). Therefore, it is likely that the CKNnT epidemic extends throughout the Mesoamerican region.

  5. A disease epidemic on Zizyphus mucronata in the Kruger National Park caused by Coniodictyum chevalieri.

    Science.gov (United States)

    Maier, Wolfgang; Khoza, Thembi; Harmse, Neil; Wingfield, Brenda D; Wingfield, Michael J

    2006-01-01

    This study records a severe outbreak of a disease on Zizyphus mucronata (Rhamnaceae) in Greater Kruger National Park, South Africa. The causal agent of the disease was found to be Coniodictyum chevalieri, a fungus previously believed to be very rare. Detailed illustrations of the symptoms and fungus are presented in order to facilitate future studies. The known geographical distribution of Coniodictyum is presented in relation to the distribution of its host, and a short review of its systematic history is also given. This also treats an invalidly published species name in South Africa, which has confused the literature. A DNA-based phylogeny is presented for the pathogen and this reflects the unique nature of its geographical distribution and biology.

  6. Growing Epidemic of Coronary Heart Disease in Low- and Middle-Income Countries

    Science.gov (United States)

    Gaziano, Thomas A.; Bitton, Asaf; Anand, Shuchi; Abrahams-Gessel, Shafika; Murphy, Adrianna

    2010-01-01

    Coronary heart disease (CHD) is the single largest cause of death in the developed countries and is one of the leading causes of disease burden in developing countries. In 2001, there were 7.3 million deaths due to CHD worldwide. Three-fourths of global deaths due to CHD occurred in the low and middle-income countries. The rapid rise in CHD burden in most of the low and middle and income countries is due to socio-economic changes, increase in life span and acquisition of lifestyle related risk factors. The CHD death rate, however, varies dramatically across the developing countries. The varying incidence, prevalence, and mortality rates reflect the different levels of risk factors, other competing causes of death, availability of resources to combat CVD, and the stage of epidemiologic transition that each country or region finds itself. The economic burden of CHD is equally large but solutions exist to manage this growing burden. PMID:20109979

  7. Using multitype branching processes to quantify statistics of disease outbreaks in zoonotic epidemics

    Science.gov (United States)

    Singh, Sarabjeet; Schneider, David J.; Myers, Christopher R.

    2014-03-01

    Branching processes have served as a model for chemical reactions, biological growth processes, and contagion (of disease, information, or fads). Through this connection, these seemingly different physical processes share some common universalities that can be elucidated by analyzing the underlying branching process. In this work we focus on coupled branching processes as a model of infectious diseases spreading from one population to another. An exceedingly important example of such coupled outbreaks are zoonotic infections that spill over from animal populations to humans. We derive several statistical quantities characterizing the first spillover event from animals to humans, including the probability of spillover, the first passage time distribution for human infection, and disease prevalence in the animal population at spillover. Large stochastic fluctuations in those quantities can make inference of the state of the system at the time of spillover difficult. Focusing on outbreaks in the human population, we then characterize the critical threshold for a large outbreak, the distribution of outbreak sizes, and associated scaling laws. These all show a strong dependence on the basic reproduction number in the animal population and indicate the existence of a novel multicritical point with altered scaling behavior. The coupling of animal and human infection dynamics has crucial implications, most importantly allowing for the possibility of large human outbreaks even when human-to-human transmission is subcritical.

  8. Discrete epidemic models.

    Science.gov (United States)

    Brauer, Fred; Feng, Zhilan; Castillo-Chavez, Carlos

    2010-01-01

    The mathematical theory of single outbreak epidemic models really began with the work of Kermack and Mackendrick about decades ago. This gave a simple answer to the long-standing question of why epidemics woould appear suddenly and then disappear just as suddenly without having infected an entire population. Therefore it seemed natural to expect that theoreticians would immediately proceed to expand this mathematical framework both because the need to handle recurrent single infectious disease outbreaks has always been a priority for public health officials and because theoreticians often try to push the limits of exiting theories. However, the expansion of the theory via the inclusion of refined epidemiological classifications or through the incorporation of categories that are essential for the evaluation of intervention strategies, in the context of ongoing epidemic outbreaks, did not materialize. It was the global threat posed by SARS in that caused theoreticians to expand the Kermack-McKendrick single-outbreak framework. Most recently, efforts to connect theoretical work to data have exploded as attempts to deal with the threat of emergent and re-emergent diseases including the most recent H1N1 influenza pandemic, have marched to the forefront of our global priorities. Since data are collected and/or reported over discrete units of time, developing single outbreak models that fit collected data naturally is relevant. In this note, we introduce a discrete-epidemic framework and highlight, through our analyses, the similarities between single-outbreak comparable classical continuous-time epidemic models and the discrete-time models introduced in this note. The emphasis is on comparisons driven by expressions for the final epidemic size.

  9. Post-epidemic Chikungunya disease on Reunion Island: course of rheumatic manifestations and associated factors over a 15-month period.

    Directory of Open Access Journals (Sweden)

    Daouda Sissoko

    Full Text Available Although the acute manifestations of Chikungunya virus (CHIKV illness are well-documented, few data exist about the long-term rheumatic outcomes of CHIKV-infected patients. We undertook between June and September 2006 a retrospective cohort study aimed at assessing the course of late rheumatic manifestations and investigating potential risk factors associated with the persistence of these rheumatic manifestations over 15 months. 147 participants (>16 yrs with laboratory-confirmed CHIKV disease diagnosed between March 1 and June 30, 2005, were identified through a surveillance database and interviewed by telephone. At the 15-month-period evaluation after diagnosis, 84 of 147 participants (57% self-reported rheumatic symptoms. Of these 84 patients, 53 (63% reported permanent trouble while 31 (37% had recurrent symptoms. Age > or=45 years (OR = 3.9, 95% CI 1.7-9.7, severe initial joint pain (OR = 4.8, 95% CI 1.9-12.1, and presence of underlying osteoarthritis comorbidity (OR = 2.9, 95% CI 1.1-7.4 were predictors of nonrecovery. Our findings suggest that long-term CHIKV rheumatic manifestations seem to be a frequent underlying post-epidemic condition. Three independent risk factors that may aid in early recognition of patients with the highest risk of presenting prolonged CHIKV illness were identified. Such findings may be particularly useful in the development of future prevention and care strategies for this emerging virus infection.

  10. Proximity Networks and Epidemics

    CERN Document Server

    Toroczkai, Z

    2007-01-01

    Disease spread in most biological populations requires the proximity of agents. In populations where the individuals have spatial mobility, the contact graph is generated by the "collision dynamics" of the agents, and thus the evolution of epidemics couples directly to the spatial dynamics of the population. We first briefly review the properties and the methodology of an agent-based simulation (EPISIMS) to model disease spread in realistic urban dynamic contact networks. Using the data generated by this simulation, we introduce the notion of dynamic proximity networks which takes into account the relevant time scales for disease spread: contact duration, infectivity period and rate of contact creation. This approach promises to be a good candidate for a unified treatment of epidemic types that are driven by agent collision dynamics. In particular, using a simple model, we show that it can can account for the observed qualitative differences between the degree distributions of contact graphs of diseases with ...

  11. A discrete epidemic model for bovine Babesiosis disease and tick populations

    Science.gov (United States)

    Aranda, Diego F.; Trejos, Deccy Y.; Valverde, Jose C.

    2017-06-01

    In this paper, we provide and study a discrete model for the transmission of Babesiosis disease in bovine and tick populations. This model supposes a discretization of the continuous-time model developed by us previously. The results, here obtained by discrete methods as opposed to continuous ones, show that similar conclusions can be obtained for the discrete model subject to the assumption of some parametric constraints which were not necessary in the continuous case. We prove that these parametric constraints are not artificial and, in fact, they can be deduced from the biological significance of the model. Finally, some numerical simulations are given to validate the model and verify our theoretical study.

  12. Impact of infectious disease epidemics on tuberculosis diagnostic, management, and prevention services: experiences and lessons from the 2014-2015 Ebola virus disease outbreak in West Africa.

    Science.gov (United States)

    Ansumana, Rashid; Keitell, Samuel; Roberts, Gregory M T; Ntoumi, Francine; Petersen, Eskild; Ippolito, Giuseppe; Zumla, Alimuddin

    2017-03-01

    The World Health Organization (WHO) Global Tuberculosis Report 2015 states that 28% of the world's 9.6 million new tuberculosis (TB) cases are in the WHO Africa Region. The Mano River Union (MRU) countries of West Africa-Guinea, Sierra Leone, and Liberia-have made incremental sustained investments into TB control programmes over the past two decades. The devastating Ebola virus disease (EVD) outbreak of 2014-2015 in West Africa impacted significantly on all sectors of the healthcare systems in the MRU countries, including the TB prevention and control programmes. The EVD outbreak also had an adverse impact on the healthcare workforce and healthcare service delivery. At the height of the EVD outbreak, numerous staff members in all MRU countries contracted EBV at the Ebola treatment units and died. Many healthcare workers were also infected in healthcare facilities that were not Ebola treatment units but were national hospitals and peripheral health units that were unprepared for receiving patients with EVD. In all three MRU countries, the disruption to TB services due to the EVD epidemic will no doubt have increased Mycobacterium tuberculosis transmission, TB morbidity and mortality, and decreased patient adherence to TB treatment, and the likely impact will not be known for several years to come. In this viewpoint, the impact that the EVD outbreak had on TB diagnostic, management, and prevention services is described. Vaccination against TB with BCG in children under 5 years of age was affected adversely by the EVD epidemic. The EVD outbreak was a result of global failure and represents yet another 'wake-up call' to the international community, and particularly to African governments, to reach a consensus on new ways of thinking at the national, regional, and global levels for building healthcare systems that can sustain their function during outbreaks. This is necessary so that other disease control programmes (like those for TB, malaria, and HIV) are not

  13. The emerging global epidemic of paediatric inflammatory bowel disease--causes and consequences.

    Science.gov (United States)

    Malmborg, P; Hildebrand, H

    2016-03-01

    Two decades ago, paediatric inflammatory bowel disease (IBD) drew only modest interest from the international paediatric community. Since then, dramatically globally increasing incidence rates have made childhood-onset IBD a priority for most paediatric gastroenterologists. The emerging pandemia of paediatric IBD has fuelled a quest to identify the recent changes in early life exposures that could explain the increasing risk for IBD amongst today's children. Treatment of children with IBD should aim for symptom control but should also target restoration of growth and prevention of pubertal delay. The paediatric IBD phenotype seems to be characterized by more extensive disease location, and some comparative studies have suggested that childhood-onset IBD also represents a more severe phenotype than the adult-onset IBD form. In this review, we analyse recent global incidence trends of paediatric IBD. We present an update on the known and suggested risk factors that could explain the emerging global epidemia of paediatric IBD. We also draw attention to differences in treatment between children and adults with IBD. Finally, we highlight latest follow-up studies that question the proposed dynamic and aggressive nature of childhood-onset IBD.

  14. Combating the Epidemic of Obesity and Cardiovascular Disease: Perspectives from School-aged Children

    Directory of Open Access Journals (Sweden)

    Lavon Young

    2006-09-01

    Full Text Available This study was designed to assess students’ perceptions of the obstacles to positive dietary practices and increased physical activity and to solicit the students’ recommendations for addressing and possibly reducing the negative practices that are associated with the rise in obesity and the development of cardiovascular diseases. Data for the study were obtained from the administration of the 2005 Project Health High School Survey (PHHSS which measured the students’ perceptions regarding obstacles to eating more nutritious, healthier foods and obstacles to participating in daily physical activity. The reasons for students’ lack of interest in practicing more life-healthy behaviors are ranked and recorded. Some of the students indicated that they usually ate what they liked to eat, and the decision about what to eat was made because of the taste of the food without regard for any health consequence or negative health outcomes. Finding ways to reach these students at their young ages is the key to successfully combating the high prevalence of obesity and the development of other chronic diseases in childhood, as well as in adulthood.

  15. Strengthening Health Systems While Responding to a Health Crisis: Lessons Learned by a Nongovernmental Organization During the Ebola Virus Disease Epidemic in Sierra Leone

    Science.gov (United States)

    Cancedda, Corrado; Davis, Sheila M.; Dierberg, Kerry L.; Lascher, Jonathan; Kelly, J. Daniel; Barrie, Mohammed Bailor; Koroma, Alimamy Philip; George, Peter; Kamara, Adikali Alpha; Marsh, Ronald; Sumbuya, Manso S.; Nutt, Cameron T.; Scott, Kirstin W.; Thomas, Edgar; Bollbach, Katherine; Sesay, Andrew; Barrie, Ahmidu; Barrera, Elizabeth; Barron, Kathryn; Welch, John; Bhadelia, Nahid; Frankfurter, Raphael G.; Dahl, Ophelia M.; Das, Sarthak; Rollins, Rebecca E.; Eustis, Bryan; Schwartz, Amanda; Pertile, Piero; Pavlopoulos, Ilias; Mayfield, Allan; Marsh, Regan H.; Dibba, Yusupha; Kloepper, Danielle; Hall, Andrew; Huster, Karin; Grady, Michael; Spray, Kimberly; Walton, David A.; Daboh, Fodei; Nally, Cora; James, Sahr; Warren, Gabriel S.; Chang, Joyce; Drasher, Michael; Lamin, Gina; Bangura, Sherry; Miller, Ann C.; Michaelis, Annie P.; McBain, Ryan; Broadhurst, M. Jana; Murray, Megan; Richardson, Eugene T.; Philip, Ted; Gottlieb, Gary L.; Mukherjee, Joia S.; Farmer, Paul E.

    2016-01-01

    An epidemic of Ebola virus disease (EVD) beginning in 2013 has claimed an estimated 11 310 lives in West Africa. As the EVD epidemic subsides, it is important for all who participated in the emergency Ebola response to reflect on strengths and weaknesses of the response. Such reflections should take into account perspectives not usually included in peer-reviewed publications and after-action reports, including those from the public sector, nongovernmental organizations (NGOs), survivors of Ebola, and Ebola-affected households and communities. In this article, we first describe how the international NGO Partners In Health (PIH) partnered with the Government of Sierra Leone and Wellbody Alliance (a local NGO) to respond to the EVD epidemic in 4 of the country's most Ebola-affected districts. We then describe how, in the aftermath of the epidemic, PIH is partnering with the public sector to strengthen the health system and resume delivery of regular health services. PIH's experience in Sierra Leone is one of multiple partnerships with different stakeholders. It is also one of rapid deployment of expatriate clinicians and logistics personnel in health facilities largely deprived of health professionals, medical supplies, and physical infrastructure required to deliver health services effectively and safely. Lessons learned by PIH and its partners in Sierra Leone can contribute to the ongoing discussion within the international community on how to ensure emergency preparedness and build resilient health systems in settings without either. PMID:27688219

  16. A distinct Bemisia tabaci (Gennadius) (Hemiptera: Sternorrhyncha: Aleyrodidae) genotype cluster is associated with the epidemic of severe cassava mosaic virus disease in Uganda.

    Science.gov (United States)

    Legg, J P; French, R; Rogan, D; Okao-Okuja, G; Brown, J K

    2002-07-01

    During the 1990s, an epidemic of cassava mosaic virus disease caused major losses to cassava production in Uganda. Two factors associated with the epidemic were the occurrence of a novel recombinant begomovirus, EACMV-Ug, and unusually high populations of the whitefly vector, Bemisia tabaci. Here we present molecular evidence for the occurrence of two cassava-colonizing B. tabaci genotype clusters, Ug1 and Ug2, one of which, Ug2, can be consistently associated with the CMD epidemic in Uganda at the time of collection in 1997. By contrast, a second genotype cluster, Ug1, only occurred 'at' or 'ahead of' the epidemic 'front', sometimes in mixtures with Ug2. Comparison of mitochondrial cytochrome oxidase I gene sequences for Ug1 and Ug2 and well-studied B. tabaci reference populations indicated that the two Ugandan populations exhibited approximately 8% divergence, suggesting they represent distinct sub-Saharan African lineages. Neither Ugandan genotype cluster was identified as the widely distributed, polyphagous, and highly fecund B biotype of Old World origin, with which they both diverged by approximately 8%. Within genotype cluster divergence of Ug1 at 0.61 +/- 0.1% was twice that of Ug2 at 0.35 +/- 0.1%. Mismatch analysis suggested that Ug2 has undergone a recent population expansion and may be of nonUgandan origin, whereas Ug1 has diverged more slowly, and is likely to be an indigenous genotype cluster.

  17. Predicting and Evaluating the Epidemic Trend of Ebola Virus Disease in the 2014-2015 Outbreak and the Effects of Intervention Measures.

    Directory of Open Access Journals (Sweden)

    Zuiyuan Guo

    Full Text Available We constructed dynamic Ebola virus disease (EVD transmission models to predict epidemic trends and evaluate intervention measure efficacy following the 2014 EVD epidemic in West Africa. We estimated the effective vaccination rate for the population, with basic reproduction number (R0 as the intermediate variable. Periodic EVD fluctuation was analyzed by solving a Jacobian matrix of differential equations based on a SIR (susceptible, infective, and removed model. A comprehensive compartment model was constructed to fit and predict EVD transmission patterns, and to evaluate the effects of control and prevention measures. Effective EVD vaccination rates were estimated to be 42% (31-50%, 45% (42-48%, and 51% (44-56% among susceptible individuals in Guinea, Liberia and Sierra Leone, respectively. In the absence of control measures, there would be rapid mortality in these three countries, and an EVD epidemic would be likely recur in 2035, and then again 8~9 years later. Oscillation intervals would shorten and outbreak severity would decrease until the periodicity reached ~5.3 years. Measures that reduced the spread of EVD included: early diagnosis, treatment in isolation, isolating/monitoring close contacts, timely corpse removal, post-recovery condom use, and preventing or quarantining imported cases. EVD may re-emerge within two decades without control and prevention measures. Mass vaccination campaigns and control and prevention measures should be instituted to prevent future EVD epidemics.

  18. A discrete epidemic model for bovine Babesiosis disease and tick populations

    Directory of Open Access Journals (Sweden)

    Aranda Diego F.

    2017-06-01

    Full Text Available In this paper, we provide and study a discrete model for the transmission of Babesiosis disease in bovine and tick populations. This model supposes a discretization of the continuous-time model developed by us previously. The results, here obtained by discrete methods as opposed to continuous ones, show that similar conclusions can be obtained for the discrete model subject to the assumption of some parametric constraints which were not necessary in the continuous case. We prove that these parametric constraints are not artificial and, in fact, they can be deduced from the biological significance of the model. Finally, some numerical simulations are given to validate the model and verify our theoretical study.

  19. Assessing Hypothetical Gravity Control Propulsion

    CERN Document Server

    Millis, M G

    2006-01-01

    Gauging the benefits of hypothetical gravity control propulsion is difficult, but addressable. The major challenge is that such breakthroughs are still only notional concepts rather than being specific methods from which performance can be rigorously quantified. A recent assessment by Tajmar and Bertolami used the rocket equation to correct naive misconceptions, but a more fundamental analysis requires the use of energy as the basis for comparison. The energy of a rocket is compared to an idealized space drive for the following cases: Earth-to-orbit, interstellar transit, and levitation. The space drive uses 3.6 times less energy for Earth to orbit. For deep space travel, space drive energy scales as the square of delta-v, while rocket energy scales exponentially. This has the effect of rendering a space drive 150-orders-of-magnitude better than a 17,000-sec Specific Impulse rocket for sending a modest 5000 kg probe to traverse 5 light-years in 50 years. Indefinite levitation, which is impossible for a rocket...

  20. Preventing a Cardiovascular Disease Epidemic among Indigenous Populations through Lifestyle Changes

    Directory of Open Access Journals (Sweden)

    Lee Stoner

    2012-01-01

    Full Text Available Cardiovascular disease (CVD is the driving force behind the discrepancy in life expectancy between indigenous and non-indigenous groups in many countries. Preceding CVD many indigenous groups exhibit a cluster of cardiometabolic risk factors, including overweight-obesity, diabetes, high cholesterol, and high blood pressure. In turn, modifiable lifestyle risk factors contribute to the development of this cluster of cardiometabolic conditions. Modifiable lifestyle risk factors include, but are not limited to, physical inactivity, poor nutrition, excessive alcohol consumption, and cigarette smoking. Notably, these metabolic and lifestyle risk factors are relatively simple to monitor and track. The current review will look at modifiable cardiometabolic (overweight-obesity, diabetes mellitus, high cholesterol, and high blood pressure and lifestyle (physical inactivity, poor nutrition, risky alcohol behavior, and cigarette smoking risk factors among indigenous populations from Australia (Aboriginal Australians and Torres Strait Islanders, New Zealand (Mβori and the United States (Native Americans. Discussion will focus on the causal relationship between modifiable lifestyle risk factors and cardiometabolic outcomes, as well as, simple measurements for tracking these risk factors.

  1. Economics of eradicating Foot-and-Mouth disease epidemics with alternative control strategies

    Directory of Open Access Journals (Sweden)

    RHM Bergevoet

    2014-01-01

    Full Text Available The paper presents an economic analysis of Foot-and-Mouth Disease (FMD control strategies for livestock herds. Alternative vaccination-to-live control strategies were compared to the strategy that involves culling of all susceptible animals in an area of 1 km around infected herds in addition to standard measures as culling of infected herds, pre-emptive slaughter of contact herds, establishment of control and surveillance zones. Vaccination strategies differed with respect to the radius of vaccination around infected farms (2 km versus 5 km. As an example to illustrate the economic consequences the Netherlands was used. These strategies were evaluated for a Sparsely Populated Livestock Areas (SPLA with less than 2 farms/km² and a Densely Populated Livestock Areas (DPLA with more than 4 farms/km². Results of the partial budgeting FMD model revealed that for DPLA a control strategy which includes a vaccination radius of 2 km is most cost effective. For SPLA a control strategy which includes a 1 km culling radius around an infected farm is most cost effective.

  2. Global health security: the wider lessons from the west African Ebola virus disease epidemic.

    Science.gov (United States)

    Heymann, David L; Chen, Lincoln; Takemi, Keizo; Fidler, David P; Tappero, Jordan W; Thomas, Mathew J; Kenyon, Thomas A; Frieden, Thomas R; Yach, Derek; Nishtar, Sania; Kalache, Alex; Olliaro, Piero L; Horby, Peter; Torreele, Els; Gostin, Lawrence O; Ndomondo-Sigonda, Margareth; Carpenter, Daniel; Rushton, Simon; Lillywhite, Louis; Devkota, Bhimsen; Koser, Khalid; Yates, Rob; Dhillon, Ranu S; Rannan-Eliya, Ravi P

    2015-05-09

    The Ebola virus disease outbreak in West Africa was unprecedented in both its scale and impact. Out of this human calamity has come renewed attention to global health security--its definition, meaning, and the practical implications for programmes and policy. For example, how does a government begin to strengthen its core public health capacities, as demanded by the International Health Regulations? What counts as a global health security concern? In the context of the governance of global health, including WHO reform, it will be important to distil lessons learned from the Ebola outbreak. The Lancet invited a group of respected global health practitioners to reflect on these lessons, to explore the idea of global health security, and to offer suggestions for next steps. Their contributions describe some of the major threats to individual and collective human health, as well as the values and recommendations that should be considered to counteract such threats in the future. Many different perspectives are proposed. Their common goal is a more sustainable and resilient society for human health and wellbeing.

  3. Heterogeneous edge weights promote epidemic diffusion in weighted evolving networks

    Science.gov (United States)

    Duan, Wei; Song, Zhichao; Qiu, Xiaogang

    2016-08-01

    The impact that the heterogeneities of links’ weights have on epidemic diffusion in weighted networks has received much attention. Investigating how heterogeneous edge weights affect epidemic spread is helpful for disease control. In this paper, we study a Reed-Frost epidemic model in weighted evolving networks. Our results indicate that a higher heterogeneity of edge weights leads to higher epidemic prevalence and epidemic incidence at earlier stage of epidemic diffusion in weighted evolving networks. In addition, weighted evolving scale-free networks come with a higher epidemic prevalence and epidemic incidence than unweighted scale-free networks.

  4. [From dreaded epidemic to rare disease - smallpox in Sweden 1750-1900].

    Science.gov (United States)

    Sköld, P

    1994-01-01

    Smallpox contributed to the death of 300,000 people in Sweden between 1750 and 1800. It was one of the most feared diseases of the time. Most victims were children under the age of 10 years. It is estimated that one out of every ten children died from smallpox. The mortality rate was between 10% and 20% but those who survived faced severe complications. Most common were the disfiguring pockmarks among those previously infected. It turned out that women who had contracted smallpox married much later in life than the healthy. Also, both female and male fertility was lowered by smallpox infection. By the mid 1750s inoculation was introduced in Sweden. This was a preventive method where a mild infection was given by putting smallpox matter into an incision in the skin. Success was restricted to the wealthy, even if the doctors tried to reach the common people. The main reasons were lack of confidence for doctors, medical and epidemiological risks, costs and an ineffective organization. In 1801 Eberhard Zacharias Munch of Rosenschöld performed the first vaccination with cowpox matter in Sweden. In a few years an extensive practise was stabilized, which made the Swedish population one of the best vaccinated in the world. Moreover, a unique registration was compiled which, together with the parish records, makes the country one of the best documented. The main reasons behind the success was previous experiences of inoculation, international influences, abolition of the physicians monopoly, an effective organization, better opportunities for financing and rewards, and the compulsory law of 1816.

  5. Reconstructing the origin and transmission dynamics of the 1967-68 foot-and-mouth disease epidemic in the United Kingdom.

    Science.gov (United States)

    Wright, Caroline F; Knowles, Nick J; Di Nardo, Antonello; Paton, David J; Haydon, Daniel T; King, Donald P

    2013-12-01

    A large epidemic of foot-and-mouth disease (FMD) occurred in the United Kingdom (UK) over a seven month period in Northwest England from late 1967 to the summer of 1968. This was preceded by a number of smaller FMD outbreaks in the country, two in 1967, in Hampshire and Warwickshire and one in Northumberland during 1966. The causative agent of all four events was identified as FMD virus (FMDV) serotype O and the source of the large epidemic was attributed to infected bone marrow in lamb products imported from Argentina. However, the diagnostic tools available at the time were unable to entirely rule out connections with the earlier UK FMD outbreaks, as well as other potential sources from Europe. The aim of this study was to apply molecular sequencing to investigate the likely source of this epidemic using VP1 region and full genome (FG) sequences determined directly from clinical epithelium samples (n=13) or cell culture isolates (n=6), from this and contemporary outbreaks in the UK, Europe and South America. Analysis of the VP1 sequences provided evidence for at least three separate incursions of FMDV into the UK including one independent introduction that was responsible for the main 1967/68 epidemic. Analysis of FG sequences from the main 1967/68 outbreak (n=10) revealed nucleotide substitutions at 94 genomic sites providing evidence for the linear accumulation of nucleotide substitutions (rate=2.42 × 10(-)(5)nt substitutions/site/day). However, there were five samples where this linear relationship was absent, indicating evolutional dormancy of the virus, presumably outside a host. These results help define the evolutionary dynamics of FMDV during an epidemic and contribute to the knowledge and understanding from which to base future outbreak control strategies.

  6. Heterogeneity in District-Level Transmission of Ebola Virus Disease during the 2013-2015 Epidemic in West Africa.

    Directory of Open Access Journals (Sweden)

    Fabienne Krauer

    2016-07-01

    Full Text Available The Ebola virus disease (EVD epidemic in West Africa in 2013-2015 spread heterogeneously across the three hardest-hit countries Guinea, Liberia and Sierra Leone and the estimation of national transmission of EVD provides little information about local dynamics. To investigate district-level transmissibility of EVD, we applied a statistical modelling approach to estimate the basic reproduction number (R0 for each affected district and each country using weekly incident case numbers. We estimated growth rates during the early exponential phase of the outbreak using exponential regression of the case counts on the first eight weeks since onset. To take into account the heterogeneity between and within countries, we fitted a mixed effects model and calculated R0 based on the predicted individual growth rates and the reported serial interval distribution. At district level, R0 ranged from 0.36 (Dubréka to 1.72 (Beyla in Guinea, from 0.53 (Maryland to 3.37 (Margibi in Liberia and from 1.14 (Koinadugu to 2.73 (Western Rural in Sierra Leone. At national level, we estimated an R0 of 0.97 (95% CI 0.77-1.18 for Guinea, 1.26 (95% CI 0.98-1.55 for Liberia and 1.66 (95% CI 1.32-2.00 for Sierra Leone. Socio-demographic variables related to urbanisation such as high population density and high wealth index were found positively associated with R0 suggesting that the consequences of fast urban growth in West Africa may have contributed to the increased spread of EVD.

  7. Using Web Search Query Data to Monitor Dengue Epidemics: A New Model for Neglected Tropical Disease Surveillance

    Science.gov (United States)

    Chan, Emily H.; Sahai, Vikram; Conrad, Corrie; Brownstein, John S.

    2011-01-01

    Background A variety of obstacles including bureaucracy and lack of resources have interfered with timely detection and reporting of dengue cases in many endemic countries. Surveillance efforts have turned to modern data sources, such as Internet search queries, which have been shown to be effective for monitoring influenza-like illnesses. However, few have evaluated the utility of web search query data for other diseases, especially those of high morbidity and mortality or where a vaccine may not exist. In this study, we aimed to assess whether web search queries are a viable data source for the early detection and monitoring of dengue epidemics. Methodology/Principal Findings Bolivia, Brazil, India, Indonesia and Singapore were chosen for analysis based on available data and adequate search volume. For each country, a univariate linear model was then built by fitting a time series of the fraction of Google search query volume for specific dengue-related queries from that country against a time series of official dengue case counts for a time-frame within 2003–2010. The specific combination of queries used was chosen to maximize model fit. Spurious spikes in the data were also removed prior to model fitting. The final models, fit using a training subset of the data, were cross-validated against both the overall dataset and a holdout subset of the data. All models were found to fit the data quite well, with validation correlations ranging from 0.82 to 0.99. Conclusions/Significance Web search query data were found to be capable of tracking dengue activity in Bolivia, Brazil, India, Indonesia and Singapore. Whereas traditional dengue data from official sources are often not available until after some substantial delay, web search query data are available in near real-time. These data represent valuable complement to assist with traditional dengue surveillance. PMID:21647308

  8. Using web search query data to monitor dengue epidemics: a new model for neglected tropical disease surveillance.

    Directory of Open Access Journals (Sweden)

    Emily H Chan

    2011-05-01

    Full Text Available BACKGROUND: A variety of obstacles including bureaucracy and lack of resources have interfered with timely detection and reporting of dengue cases in many endemic countries. Surveillance efforts have turned to modern data sources, such as Internet search queries, which have been shown to be effective for monitoring influenza-like illnesses. However, few have evaluated the utility of web search query data for other diseases, especially those of high morbidity and mortality or where a vaccine may not exist. In this study, we aimed to assess whether web search queries are a viable data source for the early detection and monitoring of dengue epidemics. METHODOLOGY/PRINCIPAL FINDINGS: Bolivia, Brazil, India, Indonesia and Singapore were chosen for analysis based on available data and adequate search volume. For each country, a univariate linear model was then built by fitting a time series of the fraction of Google search query volume for specific dengue-related queries from that country against a time series of official dengue case counts for a time-frame within 2003-2010. The specific combination of queries used was chosen to maximize model fit. Spurious spikes in the data were also removed prior to model fitting. The final models, fit using a training subset of the data, were cross-validated against both the overall dataset and a holdout subset of the data. All models were found to fit the data quite well, with validation correlations ranging from 0.82 to 0.99. CONCLUSIONS/SIGNIFICANCE: Web search query data were found to be capable of tracking dengue activity in Bolivia, Brazil, India, Indonesia and Singapore. Whereas traditional dengue data from official sources are often not available until after some substantial delay, web search query data are available in near real-time. These data represent valuable complement to assist with traditional dengue surveillance.

  9. How is Indonesia coping with its epidemic of chronic noncommunicable diseases? A systematic review with meta-analysis

    Science.gov (United States)

    Wall, Stig; Hakimi, Mohammad; Dewi, Fatwa Sari Tetra; Weinehall, Lars; Nichter, Mark; Nilsson, Maria; Kusnanto, Hari; Rahajeng, Ekowati; Ng, Nawi

    2017-01-01

    Background Chronic noncommunicable diseases (NCDs) have emerged as a huge global health problem in low- and middle-income countries. The magnitude of the rise of NCDs is particularly visible in Southeast Asia where limited resources have been used to address this rising epidemic, as in the case of Indonesia. Robust evidence to measure growing NCD-related burdens at national and local levels and to aid national discussion on social determinants of health and intra-country inequalities is needed. The aim of this review is (i) to illustrate the burden of risk factors, morbidity, disability, and mortality related to NCDs; (ii) to identify existing policy and community interventions, including disease prevention and management strategies; and (iii) to investigate how and why an inequitable distribution of this burden can be explained in terms of the social determinants of health. Methods Our review followed the PRISMA guidelines for identifying, screening, and checking the eligibility and quality of relevant literature. We systematically searched electronic databases and gray literature for English- and Indonesian-language studies published between Jan 1, 2000 and October 1, 2015. We synthesized included studies in the form of a narrative synthesis and where possible meta-analyzed their data. Results On the basis of deductive qualitative content analysis, 130 included citations were grouped into seven topic areas: risk factors; morbidity; disability; mortality; disease management; interventions and prevention; and social determinants of health. A quantitative synthesis meta-analyzed a subset of studies related to the risk factors smoking, obesity, and hypertension. Conclusions Our findings echo the urgent need to expand routine risk factor surveillance and outcome monitoring and to integrate these into one national health information system. There is a stringent necessity to reorient and enhance health system responses to offer effective, realistic, and affordable ways

  10. How is Indonesia coping with its epidemic of chronic noncommunicable diseases? A systematic review with meta-analysis.

    Science.gov (United States)

    Schröders, Julia; Wall, Stig; Hakimi, Mohammad; Dewi, Fatwa Sari Tetra; Weinehall, Lars; Nichter, Mark; Nilsson, Maria; Kusnanto, Hari; Rahajeng, Ekowati; Ng, Nawi

    2017-01-01

    Chronic noncommunicable diseases (NCDs) have emerged as a huge global health problem in low- and middle-income countries. The magnitude of the rise of NCDs is particularly visible in Southeast Asia where limited resources have been used to address this rising epidemic, as in the case of Indonesia. Robust evidence to measure growing NCD-related burdens at national and local levels and to aid national discussion on social determinants of health and intra-country inequalities is needed. The aim of this review is (i) to illustrate the burden of risk factors, morbidity, disability, and mortality related to NCDs; (ii) to identify existing policy and community interventions, including disease prevention and management strategies; and (iii) to investigate how and why an inequitable distribution of this burden can be explained in terms of the social determinants of health. Our review followed the PRISMA guidelines for identifying, screening, and checking the eligibility and quality of relevant literature. We systematically searched electronic databases and gray literature for English- and Indonesian-language studies published between Jan 1, 2000 and October 1, 2015. We synthesized included studies in the form of a narrative synthesis and where possible meta-analyzed their data. On the basis of deductive qualitative content analysis, 130 included citations were grouped into seven topic areas: risk factors; morbidity; disability; mortality; disease management; interventions and prevention; and social determinants of health. A quantitative synthesis meta-analyzed a subset of studies related to the risk factors smoking, obesity, and hypertension. Our findings echo the urgent need to expand routine risk factor surveillance and outcome monitoring and to integrate these into one national health information system. There is a stringent necessity to reorient and enhance health system responses to offer effective, realistic, and affordable ways to prevent and control NCDs through

  11. Establishing a web-based integrated surveillance system for early detection of infectious disease epidemic in rural China: a field experimental study

    Directory of Open Access Journals (Sweden)

    Yan Wei-rong

    2012-02-01

    Full Text Available Abstract Background A crucial goal of infectious disease surveillance is the early detection of epidemics, which is essential for disease control. In China, the current surveillance system is based on confirmed case reports. In rural China, it is not practical for health units to perform laboratory tests to confirm disease and people are more likely to get 'old' and emerging infectious diseases due to poor living conditions and closer contacts with wild animals and poultry. Syndromic surveillance, which collects non-specific syndromes before diagnosis, has great advantages in promoting the early detection of epidemics and reducing the necessities of disease confirmation. It will be especially effective for surveillance in resource poor settings. Methods/Design This is a field experimental study. The experimental tool is an innovative electronic surveillance system, combining syndromic surveillance with the existing case report surveillance in four selected counties in China. In the added syndromic surveillance, three types of data are collected including patients' major symptoms from health clinics, pharmaceutical sales from pharmacies and absenteeism information from primary school. In order to evaluate the early warning capability of the new added syndromic surveillance, the timelines and validity of the alert signals will be analyzed in comparison with the traditional case reporting system. The acceptability, feasibility and economic evaluation of the whole integrated surveillance system will be conducted in a before and after study design. Discussions Although syndromic surveillance system has mostly been established in developed areas, there are opportunities and advantages of developing it in rural China. The project will contribute to knowledge, experience and evidence on the establishment of an integrated surveillance system, which aims to provide early warning of disease epidemics in developing countries.

  12. Stochastic epidemic models: a survey

    CERN Document Server

    Britton, Tom

    2009-01-01

    This paper is a survey paper on stochastic epidemic models. A simple stochastic epidemic model is defined and exact and asymptotic model properties (relying on a large community) are presented. The purpose of modelling is illustrated by studying effects of vaccination and also in terms of inference procedures for important parameters, such as the basic reproduction number and the critical vaccination coverage. Several generalizations towards realism, e.g. multitype and household epidemic models, are also presented, as is a model for endemic diseases.

  13. Development of primary malignant melanoma during treatment with a TNF-α antagonist for severe Crohn’s disease: a case report and review of the hypothetical association between TNF-α blockers and cancer

    Directory of Open Access Journals (Sweden)

    Kouklakis G

    2013-03-01

    Full Text Available George Kouklakis,1 Eleni I Efremidou,2 Michael Pitiakoudis,3 Nikolaos Liratzopoulos,2 Alexandros Ch Polychronidis2 1Endoscopy Unit, 2First Surgical Department, 3Second Surgical Department, Medical School, Democritus University of Thrace, University Hospital of Alexandroupolis, Alexandroupolis, Greece Abstract: It is recognized that immunosuppression may lead to reduced immune surveillance and tumor formation. Because of the immunosuppressive properties of tumor necrosis factor (TNF-alpha (TNF-α antagonists, it is plausible that these biologics may increase the risk of the occurrence of malignancies or the reactivation of latent malignancies. TNF-α antagonists have gained momentum in the field of dermatology for treating rheumatoid arthritis and psoriasis, and they have revolutionized the treatment of other inflammatory autoimmune diseases such as refractory Crohn's disease. However, there is accumulating evidence that TNF-α inhibitors slightly increase the risk of cancer, including malignant melanoma (MM. The authors herein report the case of a 54-year-old female patient who developed a primary MM during treatment with adalimumab for severe Crohn’s disease resistant to successive medical therapies. The patient had been receiving this TNF-α blocker therapy for 3 years before the occurrence of MM. After wide surgical excision of the lesion and staging (based on Breslow thickness and Clark level, evaluation with a whole-body computed tomography scan was negative for metastatic disease. The long duration of the adalimumab therapy and the patient's lack of a predisposition to skin cancer suggest an association between anti-TNF-α drugs and melanocytic proliferation. The authors also review the literature on the potential association between anti-TNF regimens and the occurrence of malignancies such as melanocytic proliferations. There is a substantial hypothetical link between anti-TNF-α regimens such as adalimumab and the potential for cancers

  14. 芝麻黄花叶病毒病田间流行规律%Epidemic Characteristics of Sesame Yellow Mosaic Virus Disease in Fields

    Institute of Scientific and Technical Information of China (English)

    高新国; 高宇溥; 杨正生

    2016-01-01

    Objective] To study the epidemic characteristics of sesame yellow mosaic virus disease in fields to provide references for the pre-vention and control of the disease.[Method] In 2014, the appearance and epidemic characteristics of sesame yellow mosaic virus disease in fields were investigated.[ Result] The appearance and epidemic characteristics of sesame yellow mosaic virus disease in fields was associated with the combination effect of the growing stage of sesame and aphid occurrence .Sesame plants were susceptible to sesame yellow mosaic virus in the seedling and early flowering stages.The morbidity peak occurred 15 d after the aphid peak.[Conclusion] Regulating the sowing date of sesame to prevent the aphid peak from occurring in the seedling and early flowering stages can effectively prevent the occurrence of sesame yellow mosaic virus disease.%[目的]明确芝麻黄花叶病毒病田间流行规律,为防治该病提供参考。[方法]于2014年调查芝麻黄花叶病毒病的田间发生、流行规律。[结果]芝麻黄花叶病毒病的发生、流行与芝麻的生育期和蚜虫发生密切相关。苗期、蕾期是感染芝麻黄花叶病毒病的敏感期。蚜虫发生高峰15 d后,病害出现发病高峰。[结论]调节芝麻播种期,使苗期、蕾期,特别是蕾期错过蚜虫发生高峰能有效预防芝麻黄花叶病毒病的发生。

  15. Epidemic centrality and the underestimated epidemic impact on network peripheral nodes

    CERN Document Server

    Sikic, Mile; Antulov-Fantulin, Nino; Stefancic, Hrvoje

    2011-01-01

    Studies of disease spreading on complex networks have provided a deep insight into the conditions of onset, dynamics and prevention of epidemics in human populations and malicious software propagation in computer networks. Identifying nodes which, when initially infected, infect the largest part of the network and ranking them according to their epidemic impact is a priority for public health policies. In simulations of the disease spreading in SIR model on studied empirical complex networks, it is shown that the ranking depends on the dynamical regime of the disease spreading. A possible mechanism leading to this dynamical dependence is illustrated in an analytically tractable example. A measure called epidemic centrality, averaging the epidemic impact over all possible disease spreading regimes, is introduced as a basis of epidemic ranking. Contrary to standard notion, the epidemic centrality of nodes with high degree, k-cores value or betweenness, which are structurally central, is comparable to epidemic c...

  16. A population-based, cross-sectional survey of the Zuni Pueblo: a collaborative approach to an epidemic of kidney disease.

    Science.gov (United States)

    Stidley, Christine A; Shah, Vallabh O; Narva, Andrew S; Dalton, Diane; MacCluer, Jean W; Bobelu, Arlene; Scavini, Marina; Welty, Thomas K; Zager, Philip G

    2002-02-01

    Approximately 80% of the Zuni Indians live in Zuni Pueblo in rural New Mexico. The Zuni are relatively endogamous and differ culturally and ethnically from neighboring tribes. The Zuni Pueblo is experiencing an epidemic of renal disease. The prevalence of end-stage renal disease (ESRD) among the Zuni Indians, adjusted for age and gender, is 6-fold and 21-fold higher than the prevalence rates for Native Americans and European Americans. Almost all Zuni tribal members have a relative with ESRD. This has led to strong public support for renal research. In response, the Zuni community has partnered with the Indian Health Service (IHS), University of New Mexico Health Sciences Center (UNMHSC), Southwest Foundation for Biomedical Research (SFBR), Dialysis Clinic Inc (DCI), and the National Institutes of Health (NIH) to establish a research consortium, the Zuni Kidney Project (ZKP). The goal of the ZKP is to reduce the burden of renal disease in the Zuni community. The ZKP combines traditional, population-based, epidemiologic methods with modern techniques of population genetics. The foundation of the ZKP is a population-based, cross-sectional survey (PBCSS). The PBCSS has 3 specific aims: (1) estimate the prevalence of renal disease in Zuni; (2) assess risk factors for renal disease susceptibility; and (3) identify participants for planned case-control, longitudinal cohort, and family studies designed to identify environmental, familial, and genetic risk factors for the susceptibility and/or progression of renal disease. Preliminary results of the PBCSS confirm that the epidemic of renal disease in Zuni Indians is due to high rates of both diabetic and nondiabetic renal disease.

  17. Reducing hypothetical bias in choice experiments

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Olsen, Søren Bøye; Nielsen, Rasmus Christian Fejer

    Hypothetical bias in stated preference studies is an essential problem which reduces the validity of the obtained welfare estimates for non-market goods. In the attempt to mitigate hypothetical bias, a type of reminder known as Cheap Talk, has been applied in previous studies and found to overall...... eliminate some of the hypothetical bias. The present paper tests an addition to Cheap Talk, an Opt-Out Reminder. The Opt-Out Reminder is an objective short script presented prior to the choice sets, prompting the respondent to choose the opt-out alternative, if he/she finds the proposed policy generated...... alternatives in a choice set too expensive. The results suggest that adding an Opt-Out Reminder to Cheap Talk can in fact reduce hypothetical bias even further and reduces some of the ineffectiveness of CT in relation to the survey bid range and experienced respondents....

  18. High burden of cardiovascular disease risk factors in Mexico: An epidemic of ischemic heart disease that may be on its way?

    Science.gov (United States)

    Acosta-Cázares, Benjamín; Escobedo-de la Peña, Jorge

    2010-08-01

    Whereas developed nations have witnessed a drop in the occurrence and mortality of ischemic heart disease, developing nations have recorded a constant rise. The burden of cardiovascular disease risk factors may explain this increase. We conducted a population-based cross-sectional survey to estimate the prevalence of cardiovascular risk factors in the population protected by the Mexican Social Security Institute. A total of 20,062 Mexicans, aged >or=20 years, 43.5% (8,727) male and 56.5% (11,335) female, randomly selected in a 4-stage stratified population-based sampling process were included. The most prevalent cardiovascular risk factor in men was smoking (31.9%), whereas in women, it was obesity (26.6%) and central obesity (49.7%). A similar high age-adjusted prevalence was observed in women and men for hypertension (29.7% and 28.8%), diabetes (12.94% and 12.66%), and hypercholesterolemia (13.81% and 12.36%). There was a clear age effect on the prevalence of diabetes, hypertension, and hypercholesterolemia, with increasing prevalence with aging. Smoking also had an age effect, but its prevalence increases as age diminishes. More than half of the subjects in reproductive age (20-44 years old) have at least 1 cardiovascular risk factor, mainly smoking. Cardiovascular risk factors are highly prevalent in the Mexican population, which seems to be between the second and third stages of the tobacco epidemic. The increased prevalence of risk factors clustering indicates the need for comprehensive integrated management of cardiovascular risk factors in Mexicans, with special emphasis on individuals at younger ages. Copyright 2010 Mosby, Inc. All rights reserved.

  19. Human mobility and epidemic invasion

    Science.gov (United States)

    Colizza, Vittoria

    2010-03-01

    The current H1N1 influenza pandemic is just the latest example of how human mobility helps drive infectious diseases. Travel has grown explosively in the last decades, contributing to an emerging complex pattern of traffic flows that unfolds at different scales, shaping the spread of epidemics. Restrictions on people's mobility are thus investigated to design possible containment measures. By considering a theoretical framework in terms of reaction-diffusion processes, it is possible to study the invasion dynamics of epidemics in a metapopulation system with heterogeneous mobility patterns. The system is found to exhibit a global invasion threshold that sets the critical mobility rate below which the epidemic is contained. The results provide a general framework for the understanding of the numerical evidence from detailed data-driven simulations that show the limited benefit provided by travel flows reduction in slowing down or containing an emerging epidemic.

  20. Epidemic cholera spreads like wildfire

    Science.gov (United States)

    Roy, Manojit; Zinck, Richard D.; Bouma, Menno J.; Pascual, Mercedes

    2014-01-01

    Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990-2006) and former British India (1882-1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks.

  1. Ebola Virus Disease 2013-2014 Outbreak in West Africa: An Analysis of the Epidemic Spread and Response

    Directory of Open Access Journals (Sweden)

    Orlando Cenciarelli

    2015-01-01

    Full Text Available The Ebola virus epidemic burst in West Africa in late 2013, started in Guinea, reached in a few months an alarming diffusion, actually involving several countries (Liberia, Sierra Leone, Nigeria, Senegal, and Mali. Guinea and Liberia, the first nations affected by the outbreak, have put in place measures to contain the spread, supported by international organizations; then they were followed by the other nations affected. In the present EVD outbreak, the geographical spread of the virus has followed a new route: the achievement of large urban areas at an early stage of the epidemic has led to an unprecedented diffusion, featuring the largest outbreak of EVD of all time. This has caused significant concerns all over the world: the potential reaching of far countries from endemic areas, mainly through fast transports, induced several countries to issue information documents and health supervision for individuals going to or coming from the areas at risk. In this paper the geographical spread of the epidemic was analyzed, assessing the sequential appearance of cases by geographic area, considering the increase in cases and mortality according to affected nations. The measures implemented by each government and international organizations to contain the outbreak, and their effectiveness, were also evaluated.

  2. Re-assessing the likelihood of airborne spread of foot-and-mouth disease at the start of the 1967-1968 UK foot-and-mouth disease epidemic

    DEFF Research Database (Denmark)

    Gloster, J.; Freshwater, A.; Sellers, R.F.

    2005-01-01

    development of the disease out to 60 km from the source. This conclusion is reached following a detailed epidemiological, meteorological and modelling study using original records and current modelling techniques. The role played by 'lee waves' as the mechanism for the spread is investigated. It is thought......The likelihood of airborne spread of foot-and-mouth disease at the start of the 1967-1968 epidemic is re-assessed in the light of current understanding of airborne disease spread. The findings strongly confirm those made at the time that airborne virus was the most likely cause of the rapid early...... to disease controllers if the outbreak had occurred in 2004....

  3. Re-assessing the likelihood of airborne spread of foot-and-mouth disease at the start of the 1967-1968 UK foot-and-mouth disease epidemic

    DEFF Research Database (Denmark)

    Gloster, J.; Freshwater, A.; Sellers, R.F.

    2005-01-01

    The likelihood of airborne spread of foot-and-mouth disease at the start of the 1967-1968 epidemic is re-assessed in the light of current understanding of airborne disease spread. The findings strongly confirm those made at the time that airborne virus was the most likely cause of the rapid early...... development of the disease out to 60 km from the source. This conclusion is reached following a detailed epidemiological, meteorological and modelling study using original records and current modelling techniques. The role played by 'lee waves' as the mechanism for the spread is investigated. It is thought...... to disease controllers if the outbreak had occurred in 2004....

  4. Drought, epidemic disease, and the fall of classic period cultures in Mesoamerica (AD 750-950). Hemorrhagic fevers as a cause of massive population loss.

    Science.gov (United States)

    Acuna-Soto, Rodolfo; Stahle, David W; Therrell, Matthew D; Gomez Chavez, Sergio; Cleaveland, Malcolm K

    2005-01-01

    The classical period in Mexico (AD 250-750) was an era of splendor. The city of Teotihuacan was one of the largest and most sophisticated human conglomerates of the pre-industrial world. The Mayan civilization in southeastern Mexico and the Yucatan peninsula reached an impressive degree of development at the same time. This time of prosperity came to an end during the Terminal Classic Period (AD 750-950) a time of massive population loss throughout Mesoamerica. A second episode of massive depopulation in the same area was experienced during the sixteenth century when, in less than one century, between 80% and 90% of the entire indigenous population was lost. The 16th century depopulation of Mexico constitutes one of the worst demographic catastrophes in human history. Although newly imported European and African diseases caused high mortality among the native population, the major 16th century population losses were caused by a series of epidemics of a hemorrhagic fever called Cocoliztli, a highly lethal disease unknown to both Aztec and European physicians during the colonial era. The cocoliztli epidemics occurred during the 16th century megadrought, when severe drought extended at times from central Mexico to the boreal forest of Canada, and from the Pacific to the Atlantic coast. The collapse of the cultures of the Classic Period seems also to have occurred during a time of severe drought. Tree ring and lake sediment records indicate that some of the most severe and prolonged droughts to impact North America-Mesoamerica in the past 1000-4000 years occurred between AD 650 and 1000, particularly during the 8th and 9th centuries, a period of time that coincides with the Terminal Classic Period. Based on the similarities of the climatic (severe drought) and demographic (massive population loss) events in Mesoamerica during the sixteenth century, we propose that drought-associated epidemics of hemorrhagic fever may have contributed to the massive population loss

  5. Effect of Rice Sowing Date on Occurrence of Small Brown Planthopper and Epidemics of Planthopper-Transmitted Rice Stripe Viral Disease

    Institute of Scientific and Technical Information of China (English)

    ZHU Jin-liang; ZHU Zeng-rong; ZHOU Yin; LU Qiang; SUN Xiang-liang; TAO Xian-guo; CHEN Yue; WANG Hua-di; CHENG Jia-an

    2009-01-01

    To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper (SBPH) Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted dee stripe viral (RSV) disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics (AUCPD or planthopper-day accumulation) or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger seale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.

  6. Epidemic situation and treatment progress of hand, foot and mouth disease%手足口病的流行状况与治疗进展

    Institute of Scientific and Technical Information of China (English)

    董国霞; 冷吉燕

    2008-01-01

    手足口病国内外均有散发、流行病例报道,今年安徽阜阳市出现暴发流行,目前缺乏特异、高效的抗病毒药物.对症和支持治疗是手足口病的主要治疗措施.加强监测,提高监测敏感性是控制本病流行的关键.%Objective To invastiigate epidemic situation and treatment progress of hand, foot and mouth disease in recent years. Methods Search of the epidemic situation and treatment progress of hand, foot and mouth disease from MEDLINE and CBM discs, SUmmary was employed to evaluate the results of the related research. Results HFMD prevails in part or in many parts of the world, at present it has a peak incidence. HFMD is outhreaking in the city of fuyang Anhui Province. There is not a Specific and Efficient Antiviral drugs at present. Symptomatic and supportive therapy is the major treatment for HFMD. Conclusion There is not a Specific methods of prevention, to strengthen the monitoring and Improve the sensitive of monitoring is the key of the Control of prevalence.

  7. Detection of hepatitis B surface antigen subtype adr in an epidemic of papular acrodermatitis of childhood (Gianotti's disease.

    Directory of Open Access Journals (Sweden)

    Kanzaki,Susumu

    1981-12-01

    Full Text Available Papular acrodermatitis of childhood (PAC has recently been reported to be associated with hepatitis B surface antigen (HBsAg subtype ayw. Between September, 1978, and June, 1979, we saw 14 patients with PAC in a small epidemic occurring in Iwakuni City, Japan. HBsAg was detected in sera from all patients. Subtyping of HBsAg in 11 patients showed that 8 had a determinant adr and 3 had no detectable determinant because of low antigen titers. The result suggests that factors other than the specific HBsAg subtype contribute to the development of PAC.

  8. Detection of hepatitis B surface antigen subtype adr in an epidemic of papular acrodermatitis of childhood (Gianotti's disease).

    Science.gov (United States)

    Kanzaki, S; Kanda, S; Terada, K; Nohno, S; Kumano, K; Narahara, K; Hayashi, H; Kimoto, H

    1981-12-01

    Papular acrodermatitis of childhood (PAC) has recently been reported to be associated with hepatitis B surface antigen (HBsAg) subtype ayw. Between September, 1978, and June, 1979, we saw 14 patients with PAC in a small epidemic occurring in Iwakuni City, Japan. HBsAg was detected in sera from all patients. Subtyping of HBsAg in 11 patients showed that 8 had a determinant adr and 3 had no detectable determinant because of low antigen titers. The result suggests that factors other than the specific HBsAg subtype contribute to the development of PAC.

  9. Reducing hypothetical bias in choice experiments

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Olsen, Søren Bøye; Nielsen, Rasmus Christian Fejer

    eliminate some of the hypothetical bias. The present paper tests an addition to Cheap Talk, an Opt-Out Reminder. The Opt-Out Reminder is an objective short script presented prior to the choice sets, prompting the respondent to choose the opt-out alternative, if he/she finds the proposed policy generated...... alternatives in a choice set too expensive. The results suggest that adding an Opt-Out Reminder to Cheap Talk can in fact reduce hypothetical bias even further and reduces some of the ineffectiveness of CT in relation to the survey bid range and experienced respondents....

  10. Epidemics in interconnected small-world networks

    NARCIS (Netherlands)

    Liu, M.; Li, D.; Qin, P.; Liu, C.; Wang, H.; Wang, F.

    2015-01-01

    Networks can be used to describe the interconnections among individuals, which play an important role in the spread of disease. Although the small-world effect has been found to have a significant impact on epidemics in single networks, the small-world effect on epidemics in interconnected networks

  11. The Epidemic and Control Situation of Hydatid Disease in Xinjiang%新疆包虫病流行现状与防控对策

    Institute of Scientific and Technical Information of China (English)

    李晓军; 刘志强; 努尔; 古努尔; 米晓云; 张壮志; 王文明; 赵莉; 石保新; 张文宝; 闫昊; 王光雷; 张兰江; 张旭

    2012-01-01

    包虫病是一种严重危害人畜健康的寄生虫病。新疆是包虫病高发区,本文就该病目前在新疆的流行现状和防控情况进行了综述。我国主要流行囊型包虫病和泡型包虫病。石渠棘球绦虫仅在我国青藏高原的藏狐体内找到。本文简述了我国现流行的包虫病病原体的分类和形态等;同时,还阐述了国内包虫病的流行和防控现状,指出了包虫病防控工作面临的挑战,强调了包虫病控制应注意的关键环节。归纳和总结了该病的防控具体实施措施。%Hydatid Disease (HD) is the most common parasitic diseases in people and domestic animals. The disease is hyperendemic in Xinjiang. The present review summarizes the recent epidemic situation and control of HD in Xinjiang. There are prevalent Cystic HD and Alveolar HD in China. Echinococcus shiquicus has been isolated only from Tibetan foxes (Vulpes ferrilata) in the Tibetan Plateau region of China. The taxonomy and morphology of echinococcus are described briefly. At the same time, the epidemic and control situation of HD in China are reviewed. The paper stressed the key point and challenge to control HD. The control strategy of HD are also introduced and summarized.

  12. Molecular epidemiology of human enterovirus 71 at the origin of an epidemic of fatal hand, foot and mouth disease cases in Cambodia.

    Science.gov (United States)

    Duong, Veasna; Mey, Channa; Eloit, Marc; Zhu, Huachen; Danet, Lucie; Huang, Zhong; Zou, Gang; Tarantola, Arnaud; Cheval, Justine; Perot, Philippe; Laurent, Denis; Richner, Beat; Ky, Santy; Heng, Sothy; Touch, Sok; Sovann, Ly; van Doorn, Rogier; Tan Tran, Thanh; Farrar, Jeremy J; Wentworth, David E; Das, Suman R; Stockwell, Timothy B; Manuguerra, Jean-Claude; Delpeyroux, Francis; Guan, Yi; Altmeyer, Ralf; Buchy, Philippe

    2016-09-21

    Human enterovirus 71 (EV-A71) causes hand, foot and mouth disease (HFMD). EV-A71 circulates in many countries and has caused large epidemics, especially in the Asia-Pacific region, since 1997. In April 2012, an undiagnosed fatal disease with neurological involvement and respiratory distress occurred in young children admitted to the Kantha Bopha Children's Hospital in Phnom Penh, Cambodia. Most died within a day of hospital admission, causing public panic and international concern. In this study, we describe the enterovirus (EV) genotypes that were isolated during the outbreak in 2012 and the following year. From June 2012 to November 2013, 312 specimens were collected from hospitalized and ambulatory patients and tested by generic EV and specific EV-A71 reverse transcription PCR. EV-A71 was detected in 208 clinical specimens while other EVs were found in 32 patients. The VP1 gene and/or the complete genome were generated. Our phylogenetic sequencing analysis demonstrated that 80 EV-A71 strains belonged to the C4a subgenotype and 3 EV-A71 strains belonged to the B5 genotype. Furthermore, some lineages of EV-A71 were found to have appeared in Cambodia following separate introductions from neighboring countries. Nineteen EV A (CV-A6 and CV-A16), 9 EV B (EV-B83, CV-B3, CV-B2, CV-A9, E-31, E-2 and EV-B80) and 4 EV C (EV-C116, EV-C96, CV-A20 and Vaccine-related PV-3) strains were also detected. We found no molecular markers of disease severity. We report here that EV-A71 genotype C4 was the main etiological agent of a large outbreak of HFMD and particularly of severe forms associated with central nervous system infections. The role played by other EVs in the epidemic could not be clearly established.

  13. Seroepidemiologic survey of epidemic cholera in Haiti to assess spectrum of illness and risk factors for severe disease.

    Science.gov (United States)

    Jackson, Brendan R; Talkington, Deborah F; Pruckler, James M; Fouché, M D Bernadette; Lafosse, Elsie; Nygren, Benjamin; Gómez, Gerardo A; Dahourou, Georges A; Archer, W Roodly; Payne, Amanda B; Hooper, W Craig; Tappero, Jordan W; Derado, Gordana; Magloire, Roc; Gerner-Smidt, Peter; Freeman, Nicole; Boncy, Jacques; Mintz, Eric D

    2013-10-01

    To assess the spectrum of illness from toxigenic Vibrio cholerae O1 and risk factors for severe cholera in Haiti, we conducted a cross-sectional survey in a rural commune with more than 21,000 residents. During March 22-April 6, 2011, we interviewed 2,622 residents ≥ 2 years of age and tested serum specimens from 2,527 (96%) participants for vibriocidal and antibodies against cholera toxin; 18% of participants reported a cholera diagnosis, 39% had vibriocidal titers ≥ 320, and 64% had vibriocidal titers ≥ 80, suggesting widespread infection. Among seropositive participants (vibriocidal titers ≥ 320), 74.5% reported no diarrhea and 9.0% had severe cholera (reported receiving intravenous fluids and overnight hospitalization). This high burden of severe cholera is likely explained by the lack of pre-existing immunity in this population, although the virulence of the atypical El Tor strain causing the epidemic and other factors might also play a role.

  14. Reactions to Hypothetical, Jealousy Producing Events.

    Science.gov (United States)

    Hansen, Gary L.

    1982-01-01

    Asked subjects (N=220) how they would feel about their mates' behavior in eight hypothetical situations designed to measure jealousy. Responses indicated that jealousy is likely to be a major issue. Sex role orientation is most consistently related to jealousy with sex role traditional subjects being the most jealous. (Author)

  15. Stochastic Processes in Epidemic Theory

    CERN Document Server

    Lefèvre, Claude; Picard, Philippe

    1990-01-01

    This collection of papers gives a representative cross-selectional view of recent developments in the field. After a survey paper by C. Lefèvre, 17 other research papers look at stochastic modeling of epidemics, both from a theoretical and a statistical point of view. Some look more specifically at a particular disease such as AIDS, malaria, schistosomiasis and diabetes.

  16. Copper-2 Ingestion, Plus Increased Meat Eating Leading to Increased Copper Absorption, Are Major Factors Behind the Current Epidemic of Alzheimer's Disease.

    Science.gov (United States)

    Brewer, George J

    2015-12-02

    It has become clear that copper toxicity is playing a major role in Alzheimer's disease; but why is the brain copper toxicity with cognition loss in Alzheimer's disease so much different clinically than brain copper toxicity in Wilson's disease, which results in a movement disorder? Furthermore, why is the inorganic copper of supplement pills and in drinking water so much more damaging to cognition than the organic copper in food? A recent paper, which shows that almost all food copper is copper-1, that is the copper-2 of foods reverts to the reduced copper-1 form at death or harvest, gives new insight into these questions. The body has an intestinal transport system for copper-1, Ctr1, which channels copper-1 through the liver and into safe channels. Ctr1 cannot absorb copper-2, and some copper-2 bypasses the liver, ends up in the blood quickly, and is toxic to cognition. Humans evolved to handle copper-1 safely, but not copper-2. Alzheimer's is at least in part, a copper-2 toxicity disease, while Wilson's is a general copper overload disease. In this review, we will show that the epidemiology of the Alzheimer's epidemic occurring in developed, but not undeveloped countries, fits with the epidemiology of exposure to copper-2 ingestion leached from copper plumbing and from copper supplement pill ingestion. Increased meat eating in developed countries is also a factor, because it increases copper absorption, and thus over all copper exposure.

  17. Analysis of Epidemic Situation of Infectious Diseases in Huadian City in 2015%桦甸市2015年传染病疫情分析

    Institute of Scientific and Technical Information of China (English)

    周晓丹

    2016-01-01

    目的:了解桦甸市2015年法定传染病发病情况及流行趋势。方法采用描述性流行病学方法分析桦甸市2015年法定传染病疫情资料。结果2015年全市共报告甲乙丙类法定传染病病例434例,死亡率为0.23/10万。其中乙类传染病报告9种,发病率为79.82/10万,死亡1例;丙类传染病4种,发病率为18.04/10万,无死亡报告。结论当前肺结核、病毒性肝炎、梅毒、淋病、出血热、猩红热、艾滋病、布鲁菌病、麻疹、其它感染性腹泻、流行性腮腺炎、手足口病和流行性感冒是危害我市居民身体健康的主要传染病。%Objective To study the incidence and epidemic trends of infectious disease in Huadian city in 2015.Methods A descriptive epidemiological method was used to analyze the epidemic situation of notifiable diseases in Huadian city in 2015.Results In 2015 the city's total report, there were 434 cases of infectious diseases, the death rate was 0.23/100 thousands. The class B infectious diseases were reported in 9 cases, the incidence rate was 79.82/100 thousands, 1 cases was death, there were 4 kinds of class C infectious diseases, the incidence rate was 18.04/100 thousands, no death reported.Conclusion The pulmonary tuberculosis, viral hepatitis, syphilis, gonorrhea, hemorrhagic fever, scarlet fever, AIDS, brucellosis, measles and other infectious diarrhea, mumps, hand and foot mouth disease and influenza are the main risk of infectious diseases of residents health.

  18. Structural and Functional Annotation of Hypothetical Proteins of O139

    Directory of Open Access Journals (Sweden)

    Md. Saiful Islam

    2015-06-01

    Full Text Available In developing countries threat of cholera is a significant health concern whenever water purification and sewage disposal systems are inadequate. Vibrio cholerae is one of the responsible bacteria involved in cholera disease. The complete genome sequence of V. cholerae deciphers the presence of various genes and hypothetical proteins whose function are not yet understood. Hence analyzing and annotating the structure and function of hypothetical proteins is important for understanding the V. cholerae. V. cholerae O139 is the most common and pathogenic bacterial strain among various V. cholerae strains. In this study sequence of six hypothetical proteins of V. cholerae O139 has been annotated from NCBI. Various computational tools and databases have been used to determine domain family, protein-protein interaction, solubility of protein, ligand binding sites etc. The three dimensional structure of two proteins were modeled and their ligand binding sites were identified. We have found domains and families of only one protein. The analysis revealed that these proteins might have antibiotic resistance activity, DNA breaking-rejoining activity, integrase enzyme activity, restriction endonuclease, etc. Structural prediction of these proteins and detection of binding sites from this study would indicate a potential target aiding docking studies for therapeutic designing against cholera.

  19. [Cholera++ epidemic in Kenya].

    Science.gov (United States)

    Paugam, H

    1999-03-01

    A cholera epidemic in 1997 followed on the heels of the 1992 epidemic that claimed thousands of victims in Kenya. This time, it emerged in the Migori district near the Tanzanian border, when a woman who had married in Tanzania brought her five-month-old baby to visit her parents. The infant, who contracted serious diarrhea and vomiting, died before the mother could reach a dispensary. During the funeral, a perfect opportunity for the disease to spread, those attending observed the traditional ritual of touching the corpse, and then ate and drank with the next of kin. Many developed symptoms of cholera, and several died in the next few days, even before first aid could be administered. At the Public Health Laboratory in Nairobi, analyses confirmed the presence of the Ogawa strain of Vibrio cholerae. Given the global reputation of Médecins Sans Frontières [Doctors Without Borders] in the field of cholera, the head of public health for Homa Bay District issued a call for help in August 1997, asking the team to provide preventive solutions and assess the gravity of the situation. Despite intense logistical, technical and health initiatives, the epidemic spread like wildfire. Five months after the initial outbreak, in February 1998, two Canadian nurses working for MSF in Homa Bay hurriedly surveyed the situation in Nyanza Province, which has a population of three million. The author accompanied one of these nurses, Joceline Roy, a Quebecer in her forties, on a tour that lasted more than 15 hours. Roy worked conscientiously, with great precision and energy. This narrative conveys much more than the fatigue and hazards of travel in the developing world; it tells the story of an important, but little publicized, aspect of nursing.

  20. Environmental Factors Influencing Epidemic Cholera

    Science.gov (United States)

    Jutla, Antarpreet; Whitcombe, Elizabeth; Hasan, Nur; Haley, Bradd; Akanda, Ali; Huq, Anwar; Alam, Munir; Sack, R. Bradley; Colwell, Rita

    2013-01-01

    Cholera outbreak following the earthquake of 2010 in Haiti has reaffirmed that the disease is a major public health threat. Vibrio cholerae is autochthonous to aquatic environment, hence, it cannot be eradicated but hydroclimatology-based prediction and prevention is an achievable goal. Using data from the 1800s, we describe uniqueness in seasonality and mechanism of occurrence of cholera in the epidemic regions of Asia and Latin America. Epidemic regions are located near regional rivers and are characterized by sporadic outbreaks, which are likely to be initiated during episodes of prevailing warm air temperature with low river flows, creating favorable environmental conditions for growth of cholera bacteria. Heavy rainfall, through inundation or breakdown of sanitary infrastructure, accelerates interaction between contaminated water and human activities, resulting in an epidemic. This causal mechanism is markedly different from endemic cholera where tidal intrusion of seawater carrying bacteria from estuary to inland regions, results in outbreaks. PMID:23897993

  1. Epidemic processes in complex networks

    Science.gov (United States)

    Pastor-Satorras, Romualdo; Castellano, Claudio; Van Mieghem, Piet; Vespignani, Alessandro

    2015-07-01

    In recent years the research community has accumulated overwhelming evidence for the emergence of complex and heterogeneous connectivity patterns in a wide range of biological and sociotechnical systems. The complex properties of real-world networks have a profound impact on the behavior of equilibrium and nonequilibrium phenomena occurring in various systems, and the study of epidemic spreading is central to our understanding of the unfolding of dynamical processes in complex networks. The theoretical analysis of epidemic spreading in heterogeneous networks requires the development of novel analytical frameworks, and it has produced results of conceptual and practical relevance. A coherent and comprehensive review of the vast research activity concerning epidemic processes is presented, detailing the successful theoretical approaches as well as making their limits and assumptions clear. Physicists, mathematicians, epidemiologists, computer, and social scientists share a common interest in studying epidemic spreading and rely on similar models for the description of the diffusion of pathogens, knowledge, and innovation. For this reason, while focusing on the main results and the paradigmatic models in infectious disease modeling, the major results concerning generalized social contagion processes are also presented. Finally, the research activity at the forefront in the study of epidemic spreading in coevolving, coupled, and time-varying networks is reported.

  2. Reporting of suspect cases of foot-and-mouth-disease during the 2001 epidemic in the UK, and the herd sensitivity and herd specificity of clinical diagnosis.

    Science.gov (United States)

    McLaws, Melissa; Ribble, Carl; Stephen, Craig; McNab, Bruce; Barrios, Pablo Romero

    2007-01-16

    We described the clinical diagnostic process utilized during the 2001 epidemic of foot-and-mouth-disease in the United Kingdom (UK), and considered it as a series of diagnostic tests. Premises were classified according to these diagnostic-test results and actual disease status, determined by the reference test, which in this case was one or more internationally accepted laboratory tests. The herd-level sensitivity (HSe) and herd-level specificity (HSp) of the clinical diagnostic process were calculated directly, relative to these internationally accepted reference tests. In this process, the first diagnostic test was 'routine monitoring', which resulted in the identification of suspect cases based solely on the clinical observations of farmers or veterinarians. 6762 suspect cases were identified, and the test had a HSe of 97.6% (95% C.I.: 96.7, 98.3) and a HSp of 95.2% (95% C.I.: 95.0, 95.3). Suspect cases were then subject to the second diagnostic test, termed 'declaration', which consisted of a review of a description of the clinical signs by government veterinarians. Premises that tested positive became 'clinical cases'. The HSe of this test was 97.1% (95% C.I.: 96.2, 97.9), and the HSp was 90.9% (95% C.I.: 90.1, 91.6). During the epidemic, these tests were combined and applied in series, with an overall HSe of 94.7% (95% C.I.: 93.5, 95.7) and an overall HSp of 99.6% (95% C.I.: 99.5, 99.6). We also examined the effect of a policy shift that prohibited delaying the diagnosis pending laboratory testing where the animals exhibited equivocal clinical signs.

  3. Seroepidemiologic Survey of Epidemic Cholera in Haiti to Assess Spectrum of Illness and Risk Factors for Severe Disease

    Science.gov (United States)

    Jackson, Brendan R.; Talkington, Deborah F.; Pruckler, James M.; Fouché, M. D. Bernadette; Lafosse, Elsie; Nygren, Benjamin; Gómez, Gerardo A.; Dahourou, Georges A.; Archer, W. Roodly; Payne, Amanda B.; Hooper, W. Craig; Tappero, Jordan W.; Derado, Gordana; Magloire, Roc; Gerner-Smidt, Peter; Freeman, Nicole; Boncy, Jacques; Mintz, Eric D.

    2013-01-01

    To assess the spectrum of illness from toxigenic Vibrio cholerae O1 and risk factors for severe cholera in Haiti, we conducted a cross-sectional survey in a rural commune with more than 21,000 residents. During March 22–April 6, 2011, we interviewed 2,622 residents ≥ 2 years of age and tested serum specimens from 2,527 (96%) participants for vibriocidal and antibodies against cholera toxin; 18% of participants reported a cholera diagnosis, 39% had vibriocidal titers ≥ 320, and 64% had vibriocidal titers ≥ 80, suggesting widespread infection. Among seropositive participants (vibriocidal titers ≥ 320), 74.5% reported no diarrhea and 9.0% had severe cholera (reported receiving intravenous fluids and overnight hospitalization). This high burden of severe cholera is likely explained by the lack of pre-existing immunity in this population, although the virulence of the atypical El Tor strain causing the epidemic and other factors might also play a role. PMID:24106192

  4. Some discrete SI and SIS epidemic models

    Institute of Scientific and Technical Information of China (English)

    LI Jian-quan; LOU Jie; LOU Mei-zhi

    2008-01-01

    The probability is introduced to formulate the death of individuals, the recovery of the infected individuals and incidence of epidemic disease. Based on the assumption that the number of individuals in a population is a constant, discrete-time SI and SIS epidemic models with vital dynamics are established respectively corresponding to the case that the infectives can recover from the disease or not. For these two models, the results obtained in this paper show that there is the same dynamical behavior as their corresponding continuous ones, and the threshold determining its dynamical behavior is found. Below the threshold the epidemic disease dies out eventually, above the threshold the epidemic disease becomes an endemic eventually, and the number of the infectives approaches a positive constant.

  5. High Genetic Diversity of Newcastle Disease Virus in Wild and Domestic Birds in Northeastern China from 2013 to 2015 Reveals Potential Epidemic Trends.

    Science.gov (United States)

    Zhang, Pingze; Xie, Guangyao; Liu, Xinxin; Ai, Lili; Chen, Yanyu; Meng, Xin; Bi, Yuhai; Chen, Jianjun; Sun, Yuzhang; Stoeger, Tobias; Ding, Zhuang; Yin, Renfu

    2015-12-28

    Newcastle disease (ND), caused by the virulent Newcastle disease virus (NDV), is one of the most important viral diseases of birds globally, but little is currently known regarding enzootic trends of NDV in northeastern China, especially for class I viruses. Thus, we performed a surveillance study for NDV in northeastern China from 2013 to 2015. A total 755 samples from wild and domestic birds in wetlands and live bird markets (LBMs) were collected, and 10 isolates of NDV were identified. Genetic and phylogenetic analyses showed that five isolates from LBMs belong to class I subgenotype 1b, two (one from wild birds and one from LBMs) belong to the vaccine-like class II genotype II, and three (all from wild birds) belong to class II subgenotype Ib. Interestingly, the five class I isolates had epidemiological connections with viruses from southern, eastern, and southeastern China. Our findings, together with recent prevalence trends of class I and virulent class II NDV in China, suggest possible virus transmission between wild and domestic birds and the potential for an NDV epidemic in the future.

  6. Inferring epidemic contact structure from phylogenetic trees.

    Directory of Open Access Journals (Sweden)

    Gabriel E Leventhal

    Full Text Available Contact structure is believed to have a large impact on epidemic spreading and consequently using networks to model such contact structure continues to gain interest in epidemiology. However, detailed knowledge of the exact contact structure underlying real epidemics is limited. Here we address the question whether the structure of the contact network leaves a detectable genetic fingerprint in the pathogen population. To this end we compare phylogenies generated by disease outbreaks in simulated populations with different types of contact networks. We find that the shape of these phylogenies strongly depends on contact structure. In particular, measures of tree imbalance allow us to quantify to what extent the contact structure underlying an epidemic deviates from a null model contact network and illustrate this in the case of random mixing. Using a phylogeny from the Swiss HIV epidemic, we show that this epidemic has a significantly more unbalanced tree than would be expected from random mixing.

  7. Drought and Epidemic Typhus, Central Mexico, 1655–1918

    OpenAIRE

    Burns, Jordan N.; Acuna-Soto, Rudofo; David W. Stahle

    2014-01-01

    Epidemic typhus is an infectious disease caused by the bacterium Rickettsia prowazekii and transmitted by body lice (Pediculus humanus corporis). This disease occurs where conditions are crowded and unsanitary. This disease accompanied war, famine, and poverty for centuries. Historical and proxy climate data indicate that drought was a major factor in the development of typhus epidemics in Mexico during 1655–1918. Evidence was found for 22 large typhus epidemics in central Mexico, and tree-ri...

  8. Copper-2 Ingestion, Plus Increased Meat Eating Leading to Increased Copper Absorption, Are Major Factors Behind the Current Epidemic of Alzheimer’s Disease

    Science.gov (United States)

    Brewer, George J.

    2015-01-01

    It has become clear that copper toxicity is playing a major role in Alzheimer’s disease; but why is the brain copper toxicity with cognition loss in Alzheimer’s disease so much different clinically than brain copper toxicity in Wilson’s disease, which results in a movement disorder? Furthermore, why is the inorganic copper of supplement pills and in drinking water so much more damaging to cognition than the organic copper in food? A recent paper, which shows that almost all food copper is copper-1, that is the copper-2 of foods reverts to the reduced copper-1 form at death or harvest, gives new insight into these questions. The body has an intestinal transport system for copper-1, Ctr1, which channels copper-1 through the liver and into safe channels. Ctr1 cannot absorb copper-2, and some copper-2 bypasses the liver, ends up in the blood quickly, and is toxic to cognition. Humans evolved to handle copper-1 safely, but not copper-2. Alzheimer’s is at least in part, a copper-2 toxicity disease, while Wilson’s is a general copper overload disease. In this review, we will show that the epidemiology of the Alzheimer’s epidemic occurring in developed, but not undeveloped countries, fits with the epidemiology of exposure to copper-2 ingestion leached from copper plumbing and from copper supplement pill ingestion. Increased meat eating in developed countries is also a factor, because it increases copper absorption, and thus over all copper exposure. PMID:26633489

  9. Copper-2 Ingestion, Plus Increased Meat Eating Leading to Increased Copper Absorption, Are Major Factors Behind the Current Epidemic of Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    George J. Brewer

    2015-12-01

    Full Text Available It has become clear that copper toxicity is playing a major role in Alzheimer’s disease; but why is the brain copper toxicity with cognition loss in Alzheimer’s disease so much different clinically than brain copper toxicity in Wilson’s disease, which results in a movement disorder? Furthermore, why is the inorganic copper of supplement pills and in drinking water so much more damaging to cognition than the organic copper in food? A recent paper, which shows that almost all food copper is copper-1, that is the copper-2 of foods reverts to the reduced copper-1 form at death or harvest, gives new insight into these questions. The body has an intestinal transport system for copper-1, Ctr1, which channels copper-1 through the liver and into safe channels. Ctr1 cannot absorb copper-2, and some copper-2 bypasses the liver, ends up in the blood quickly, and is toxic to cognition. Humans evolved to handle copper-1 safely, but not copper-2. Alzheimer’s is at least in part, a copper-2 toxicity disease, while Wilson’s is a general copper overload disease. In this review, we will show that the epidemiology of the Alzheimer’s epidemic occurring in developed, but not undeveloped countries, fits with the epidemiology of exposure to copper-2 ingestion leached from copper plumbing and from copper supplement pill ingestion. Increased meat eating in developed countries is also a factor, because it increases copper absorption, and thus over all copper exposure.

  10. Estimating potential epidemic size following introduction of a long-incubation disease in scale-free connected networks of milking-cow movements in Ontario, Canada.

    Science.gov (United States)

    Dubé, C; Ribble, C; Kelton, D; McNab, B

    2011-05-01

    other network-analysis measures provided biased estimates of potential epidemic size. The bow-tie approach provided a schematic representation of the level of risk of each farm in the network in spreading an infection, but overestimated the lower- and upper-bound measures of potential epidemic size because it did not account for the time sequence of shipments. Our infection-chain results suggest that introducing a long-incubation disease into the network of farms enrolled in the DHI program in Ontario that was not identified until 12 months after the incursion would, in a worst-case scenario, have resulted in 168 farms (representing 5% of all Ontario DHI herds) being infected as a consequence of adult cow movements among DHI farms. This estimate increased to 850 farms (26% of all DHI herds) if the infection were not identified for 36 months.

  11. Silent mysteries: epigenetic paradigms could hold the key to conquering the epidemic of allergy and immune disease.

    Science.gov (United States)

    Martino, D J; Prescott, Susan L

    2010-01-01

    Epigenetic mechanisms provide new insights into how environmental changes may mediate the increasing propensity for complex immune diseases such as allergic disease. There is now strong evidence that early environmental exposures play a key role in activating or silencing genes by altering DNA and histone methylation, histone acetylation and chromatin structure. These modifications determine the degree of DNA compaction and accessibility for gene transcription, altering gene expression, phenotype and disease susceptibility. While there is already evidence that a number of early environmental exposures are associated with an increased risk of allergic disease, several new studies indicate in utero microbial and dietary exposures can modify gene expression and allergic disease propensity through epigenetic modification. This review explores the evidence that immune development is under clear epigenetic regulation, including the pattern of T helper (Th)1 and Th2 cell differentiation, regulatory T cell differentiation, and more recently, Th17 development. It also considers the mechanisms of epigenetic regulation and early immune defects in allergy prone neonates. The inherent plasticity conferred by epigenetic mechanisms clearly also provides opportunities for environmental strategies that can re-programme gene expression for disease prevention. Identifying genes that are differentially silenced or activated in relation to subsequent disease will not only assist in identifying causal pathways, but may also help identify the contributing environmental factors.

  12. Epidemics of Diaporthe adunca in experimental and in natural populations of Plantago lanceolata and the effect of partial resistance on disease development

    NARCIS (Netherlands)

    Linders, E.G.A.; Van Damme, J.M.M.; Zadoks, J.C.

    1996-01-01

    Epidemics of the splash-dispersed pathogenic fungus Diaporthe adunca on its host, the perennial herb Plantago lanceolata, were followed during two consecutive years in transects at roadsides in the Netherlands. Epidemics of D. adunca were also studied on clones of a susceptible and a partially resis

  13. Environmental Assessment : Chronic wasting disease management during an epidemic occurrence at Crescent Lake National Wildlife Refuge, Garden County, Nebraska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment is needed to manage for chronic wasting disease on Crescent Lake NWR. There were two alternatives seriously considered: no action and...

  14. 辽宁省当前毛皮动物疫病流行状况及对策%Discussion on the status and countermeasures of current fur animal epidemic disease in Liaoning province

    Institute of Scientific and Technical Information of China (English)

    范治斌; 董海燕; 尚学东; 刘双鸣; 崔健

    2014-01-01

    Liaoning province is the main producing areas of fur animal in China. Whether the epi-demic disease of fur animal can be effectively controlled becomes the key factor to the healthy de-velopment of the economic animal breeding industry. This article made a discussion on the species, distribution, epidemic situation and countermeasures of fur animal epidemic disease in Liaoning province, it has guiding significance for controlling the occurrence and spreading of fur animal epidemic.%辽宁省是我国毛皮动物的主要产区,毛皮动物疫病流行能否有效控制是关系到经济动物饲养行业能否健康发展的关键因素。本文对辽宁省毛皮动物的种类、分布、疫病流行情况及相应的对策进行了简要的分析,对控制毛皮动物疫病的发生和流行有重要的指导意义。

  15. An epidemic model for the interactions between thermal regime of rivers and transmission of Proliferative Kidney Disease in salmonid fish

    Science.gov (United States)

    Carraro, Luca; Bertuzzo, Enrico; Mari, Lorenzo; Gatto, Marino; Strepparava, Nicole; Hartikainen, Hanna; Rinaldo, Andrea

    2015-04-01

    Proliferative kidney disease (PKD) affects salmonid populations in European and North-American rivers. It is caused by the endoparasitic myxozoan Tetracapsuloides bryosalmonae, which exploits freshwater bryozoans (Fredericella sultana) and salmonids as primary and secondary hosts, respectively. Incidence and mortality, which can reach up to 90-100%, are known to be strongly related to water temperature. PKD has been present in brown trout population for a long time but has recently increased rapidly in incidence and severity causing a decline in fish catches in many countries. In addition, environmental changes are feared to cause PKD outbreaks at higher latitude and altitude regions as warmer temperatures promote disease development. This calls for a better comprehension of the interactions between disease dynamics and the thermal regime of rivers, in order to possibly devise strategies for disease management. In this perspective, a spatially explicit model of PKD epidemiology in riverine host metacommunities is proposed. The model aims at summarizing the knowledge on the modes of transmission of the disease and the life-cycle of the parasite, making the connection between temperature and epidemiological parameters explicit. The model accounts for both local population and disease dynamics of bryozoans and fish and hydrodynamic dispersion of the parasite spores and hosts along the river network. The model is time-hybrid, coupling inter-seasonal and intra-seasonal dynamics, the former being described in a continuous time domain, the latter seen as time steps of a discrete time domain. In order to test the model, a case study is conducted in river Wigger (Cantons of Aargau and Lucerne, Switzerland), where data about water temperature, brown trout and bryozoan populations and PKD prevalence are being collected.

  16. Dental Epidemic Diseases and Oral Health Knowledge in People with Disabilities: a Survey in a Southwest City of China

    Institute of Scientific and Technical Information of China (English)

    Guang-wen Li; Yan Zhang; Jun Wang; Zong-ke Gao; Gang Li

    2011-01-01

    @@ PEOPLE with disabilities constitute an important group in the field of oral health care, yet have rarely been studied.Based on WHO methodol- ogy of oral health survey, data of 531 persons with disabilities in vision, hearing, intelligence or extremity, or with mental disease are collected from 4 different dis- Received for publication November 4, 2010.

  17. Modeling Epidemic Network Failures

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Fagertun, Anna Manolova

    2013-01-01

    This paper presents the implementation of a failure propagation model for transport networks when multiple failures occur resulting in an epidemic. We model the Susceptible Infected Disabled (SID) epidemic model and validate it by comparing it to analytical solutions. Furthermore, we evaluate...... the SID model’s behavior and impact on the network performance, as well as the severity of the infection spreading. The simulations are carried out in OPNET Modeler. The model provides an important input to epidemic connection recovery mechanisms, and can due to its flexibility and versatility be used...... to evaluate multiple epidemic scenarios in various network types....

  18. Epidemic thresholds in a heterogenous population with competing strains

    Institute of Scientific and Technical Information of China (English)

    Wu Qing-Chu; FU Xin-Chu; Yang Meng

    2011-01-01

    Among many epidemic models, one epidemic disease may transmit with the existence of other pathogens or other strains from the same pathogen. In this paper, we consider the case where all of the strains obey the susceptible-infectedsusceptible mechanism and compete with each other at the expense of common susceptible individuals. By using the heterogenous mean-field approach, we discuss the epidemic threshold for one of two strains. We confirm the xistence of epidemic threshold in both finite and infinite populations subject to underlying epidemic transmission. Simulations in the Barabasi-Albert(BA)scale-free networks are in good agreement with the analytical results.

  19. Factors influencing performance of internet-based biosurveillance systems used in epidemic intelligence for early detection of infectious diseases outbreaks.

    Directory of Open Access Journals (Sweden)

    Philippe Barboza

    Full Text Available BACKGROUND: Internet-based biosurveillance systems have been developed to detect health threats using information available on the Internet, but system performance has not been assessed relative to end-user needs and perspectives. METHOD AND FINDINGS: Infectious disease events from the French Institute for Public Health Surveillance (InVS weekly international epidemiological bulletin published in 2010 were used to construct the gold-standard official dataset. Data from six biosurveillance systems were used to detect raw signals (infectious disease events from informal Internet sources: Argus, BioCaster, GPHIN, HealthMap, MedISys and ProMED-mail. Crude detection rates (C-DR, crude sensitivity rates (C-Se and intrinsic sensitivity rates (I-Se were calculated from multivariable regressions to evaluate the systems' performance (events detected compared to the gold-standard 472 raw signals (Internet disease reports related to the 86 events included in the gold-standard data set were retrieved from the six systems. 84 events were detected before their publication in the gold-standard. The type of sources utilised by the systems varied significantly (p<0001. I-Se varied significantly from 43% to 71% (p=0001 whereas other indicators were similar (C-DR: p=020; C-Se, p=013. I-Se was significantly associated with individual systems, types of system, languages, regions of occurrence, and types of infectious disease. Conversely, no statistical difference of C-DR was observed after adjustment for other variables. CONCLUSION: Although differences could result from a biosurveillance system's conceptual design, findings suggest that the combined expertise amongst systems enhances early detection performance for detection of infectious diseases. While all systems showed similar early detection performance, systems including human moderation were found to have a 53% higher I-Se (p=00001 after adjustment for other variables. Overall, the use of moderation, sources

  20. Communicating Science: The Role of Centers for Disease Control and Prevention's Field-Based Epidemic Intelligence Service Officers, 2009-2014.

    Science.gov (United States)

    Coronado, Fátima; Chen, Guan M; Smith, C Kay; Glynn, M Kathleen

    2016-01-01

    A highly skilled public health workforce is needed for responding to health threats, and that workforce must be able to communicate its scientific findings effectively. We evaluated the scientific communication effectiveness of the Centers for Disease Control and Prevention's (CDC's) field-based Epidemic Intelligence Service officers (EISOs). A descriptive analysis of all scientific information products produced and submitted for institutional clearance by CDC's field-based EISOs during 2009-2014. The number of abstracts, journal manuscripts, Morbidity and Mortality Weekly Reports (MMWRs), and other information products approved by CDC during 2009-2014; the number of those products published; and of those published, the number cited in the scientific literature. During 2009-2014, a total of 152 field-based EISOs produced 835 scientific information products, including 437 abstracts, 261 manuscripts, and 103 MMWRs. The majority of scientific information products submitted for clearance were abstracts (52.3%), and infectious diseases (75.3%) constituted the majority of topics. Among the 103 MMWRs and 261 manuscripts cleared, 88 (85%) and 199 (76%) were published, respectively, with the majority also infectious disease-related. The 199 published manuscripts were cited in the scientific literature 2415 times, and the 88 published MMWRs were cited 1249 times. Field-based EISOs published their work in 74 different peer-reviewed medical and public health journals, with 54% published in journals with impact factors of 1 to 5. Field-based EISOs' publications are a measurable marker that reflects proficiency in epidemiology, written communication, and professionalism, and those publications are a direct reflection of EISOs' contribution to local and state health departments. Our study establishes a baseline for future evaluations of publication outcome of scientific information products by EISOs. Information released by EISOs provides health professionals with the scientific

  1. 寨卡病毒病及疫情发展态势研究%Zika virus disease and its current epidemic trend

    Institute of Scientific and Technical Information of China (English)

    程瑾; 叶玲玲; 郝继英; 田德桥; 陈锐; 韩铁; 刘雪涛; 郑涛

    2016-01-01

    2015年5月以来在巴西等美洲中部和南部地区发生寨卡病毒大规模暴发流行,且疫情至今不断发展,呈蔓延扩大和跨境传播趋势. 世界卫生组织2016年2月1日宣布寨卡病毒正在美洲地区"爆炸性传播",巴西密集出现的新生儿小头畸形和其他神经系统病变构成"国际关注的突发公共卫生事件". 该文概述了寨卡病毒研究进展,重点分析此次疫情状况及发展态势.%Since May 2015, the Zika virus has been spreading across South and Middle America , especially in Brazil. On Feb 1, 2016,the World Health Organization said the Zika virus spread explosively and declared the Zika virus to be an international public health emergency as the disease was linked to thousands of birth defects in Brazil .This points to the ur-gent need to prevent the Zika virus .This paper outlines the research progress and discusses the epidemic trend of the Zika virus.

  2. Preparedness for epidemic disease or bioterrorism: minimum cost planning for the location and staffing of urban point-of-dispensing centers.

    Science.gov (United States)

    Bowen, William M; Chen, Jen-Yi; Tukel, Oya I

    2014-01-01

    Urban health authorities in the United States have been charged with developing plans for providing the infrastructure necessary to dispense prophylactic medications to their populations in the case of epidemic disease outbreak or bioterrorist attack. However, no specific method for such plans has been prescribed. This article formulates and demonstrates the use of an integer programming technique for helping to solve a part of the dispensing problem faced by cities, namely that of providing the federally required infrastructure at minimum cost, using their limited time and resources. Specifically, the technique minimizes the number of point-of-dispensing (POD) centers while covering every resident in all the census tracts within the city's jurisdiction. It also determines the optimal staffing requirement in terms of the number of nurses at each POD. This article includes a demonstration of the model using real data from Cleveland, OH, a mid-sized US city. Examples are provided of data and computational results for a variety of input parameter values such as population throughput rate, POD capacities, and distance limitations. The technique can be readily adapted to a wide range of urban areas.

  3. Be-CoDiS: A Mathematical Model to Predict the Risk of Human Diseases Spread Between Countries--Validation and Application to the 2014-2015 Ebola Virus Disease Epidemic.

    Science.gov (United States)

    Ivorra, Benjamin; Ngom, Diène; Ramos, Ángel M

    2015-09-01

    Ebola virus disease is a lethal human and primate disease that currently requires a particular attention from the international health authorities due to important outbreaks in some Western African countries and isolated cases in the UK, the USA and Spain. Regarding the emergency of this situation, there is a need for the development of decision tools, such as mathematical models, to assist the authorities to focus their efforts in important factors to eradicate Ebola. In this work, we propose a novel deterministic spatial-temporal model, called Between-Countries Disease Spread (Be-CoDiS), to study the evolution of human diseases within and between countries. The main interesting characteristics of Be-CoDiS are the consideration of the movement of people between countries, the control measure effects and the use of time-dependent coefficients adapted to each country. First, we focus on the mathematical formulation of each component of the model and explain how its parameters and inputs are obtained. Then, in order to validate our approach, we consider two numerical experiments regarding the 2014-2015 Ebola epidemic. The first one studies the ability of the model in predicting the EVD evolution between countries starting from the index cases in Guinea in December 2013. The second one consists of forecasting the evolution of the epidemic by using some recent data. The results obtained with Be-CoDiS are compared to real data and other model outputs found in the literature. Finally, a brief parameter sensitivity analysis is done. A free MATLAB version of Be-CoDiS is available at: http://www.mat.ucm.es/momat/software.htm.

  4. Epidemic Status of Tick and Tick-borne Diseases in Guangdong Province%广东省蜱及蜱传播疾病流行概况

    Institute of Scientific and Technical Information of China (English)

    李娟; 孙铭飞; 姜东续; 吴大成; 吴彩艳; 廖申权; 戚南山; 吕敏娜; 杨丽云; 吴玄光

    2014-01-01

    Tick is an important contributor to vector-borne diseases in China and tick-borne diseases have at-tracted much attention because of their increasing incidence and consequent significant harm to livestock and human health.The special climate,geography resources and dietary habits in Guangdong province provide good conditions for the survival of wildlife as well as increase the chances of people contacting with animals,which is helpful for tick and tick-borne disease spread.The most commonly observed tick species in Guangdong province contain 6 genus and 21 species,and human tick-borne diseases in Guangdong prov-ince include Lyme borreliosis,Q-fever,North-Asia tick-borne spotted fever and human granulocytic ana-plasmosis.Detailed information regarding the current epidemic status of tick and major tick-borne diseases in Guangdong province were reviewed in this paper,which would make efforts in government management and research for the prevention,control,diagnosis,and treatment of tick-borne diseases,as well as for the control of ticks.%蜱在吸食动物血液的同时可传播多种病原体,引发重要的人兽共患蜱传病,给人类健康和畜牧业发展带来严重危害,具有重要的公共卫生意义。近年来不断上升的发病率愈发引起人们的关注。广东省特殊的气候、地理资源环境和饮食习惯不但为野生动植物的生存提供了良好的环境,同时也增加了人与动物接触的机会,为新的蜱种和蜱媒病传播提供了方便。目前广东省分布流行的蜱种主要涉及6属21种,已经证实存在的蜱传病有莱姆病、Q 热、北亚蜱传斑点热和人粒细胞无形体。论文就广东省蜱的种类分布以及蜱传病的流行概况做一综述,为广东省蜱传病的防控措施制定及传播机制研究提供参考。

  5. Epidemic trend of periodontal disease in elderly Chinese population, 1987–2015: a systematic review and meta-analysis

    Science.gov (United States)

    Yang, Hongmei; Xiao, Li; Zhang, Lei; Deepal, Stacytabi; Ye, Guo; Zhang, Xiaonan

    2017-01-01

    Periodontal disease is a common oral health problem in the elderly population. The prevalence varied substantially due to absence of a universal diagnostic criteria. We conducted a systematic review to identify the epidemiological characteristics of periodontal diseases among Chinese elderly people. A total of 19 articles were included. The pooled detection rates for three indicators, including bleeding on probing (BOP), pocket depth (PD) and clinical attachment loss (CAL), were 53.9% (95% CI: 43.8–63.9%), 57.0% (50.8–63.2%), and 70.1% (65.4–74.8%), respectively. No significant differences in these indicators between urban and rural population. When stratified by gender, BOP (+) detection rates did not show any differences, but the detection rates of PD ≥ 4 mm and CAL ≥ 4 mm were significantly higher in males than in females (59.3% [53.4–65.2%] versus 50.8% [43.5–58.0%], RRPD = 1.13 [1.01–1.26]; 73.8% [70.0–77.7%] versus 65.2% [60.2–70.2%], RRCAL = 1.21 [1.11–1.32]). No statistically significant differences were observed between CAL ≥ 4 mm and PD ≥ 4 mm (RR = 1.12, [0.83–1.50]). A geographical map based on available data during 1987–2015 showed wide variations of periodontal disease across the mainland China. Some factors such as heterogeneity of case definitions, no specific diagnosis of periodontitis, and variable quality of the included studies could affect the final results. Hence, further high-quality epidemiological studies with standardized diagnostic criteria are needed. PMID:28358004

  6. Sleeping with the enemy: the United Nations Development Programme and its position on the non-communicable disease epidemic.

    Science.gov (United States)

    Jacob, Anil G; Lal, Pranay G; Buragohain, Anita

    2014-02-01

    The United Nations Development Programme's (UNDP) position on non-communicable diseases (NCDs) is undermined by a key issue at the global institutional level. Fundamentally, the nature of the relationship between international development agencies and the tobacco industry is at odds with the professed public health priorities of the former. At its core, the business model of the tobacco industry is premised on the sale of addictive and disease-causing substances that fuel NCDs in the first place. The role of the United Nations system and, in particular, UNDP is to 'build nations that can withstand crisis', not to collaborate with entities that profit from crises. This simple and well-established fact cannot be overlooked. We outline an array of conflict of interests. If the effects of NCDs are ever to be reversed, then international agencies such as the UNDP ought to adhere to ethical standards in choosing partners and avoid conflict of interests. In the absence of this, the UNDP may well compromise its own agenda and proliferate NCDs rather than containing them.

  7. Hypothetical conflict situations with friends and peers

    Directory of Open Access Journals (Sweden)

    Petrović Danijela S.

    2012-01-01

    Full Text Available This paper deals with age and sex differences in preferred strategies of conflict resolution in friendship and peer relationships. The study was conducted on the sample of 286 adolescents. Conflict resolution strategies have been investigated by the method of hypothetical conflict situations. For the purposes of this research, we have created an instrument consisting of 20 hypothetical situations, with the following subjects of conflict: breaking the agreement, non-compliance with opinion differences, provocations, dishonesty and stubbornness. Conflict resolution strategies we examined were giving in, withdrawal, competition and problem solving. The results have shown that problem solving is the dominant strategy of adolescents in conflict with friends, while in peer conflicts they more often opt for competition. Age differences are reflected in the fact that older adolescents are more likely to choose problem solving than younger, whereas younger adolescents are more likely to choose a retreat (withdrawal strategy than older. Girls are more prone to choosing problem solving than boys, who, on the other hand, tend to withdraw more than girls. Also, gender of the other person in the conflict is proved to be important - in conflict with male peers, adolescents choose competition to a greater extent and withdraw to a minor extent, compared to when they are in conflict with female peers. The results have practical implications as well. In programs for teaching constructive conflict resolution that are designed for younger adolescents there should be more emphasis on empowerment and training for assertive behaviour. In addition, when teaching about constructive conflict resolution strategies, it is important to consider the gender of adolescents as well as the gender of the person with whom they are in conflict.

  8. Effect on the Construction of Prevention System in Animal Epidemic Disease in Wujiang Town%甘州区乌江镇动物防疫体系建设的实效

    Institute of Scientific and Technical Information of China (English)

    赵福堂

    2012-01-01

    稳定基层防疫队伍是畜牧业发展的关键,本文分析了甘州区乌江镇村级防疫队伍的现状,主要就村级动物防疫员的选择、职责、管理等方面的作法进行了总结,并对防疫制度的落实、责任的明确、协助上级完成防疫任务等具体情况进行了分析。%To stabilize the epidemic prevention parade at basement layer was a key factor for the development of animal husbandry.This paper analyzed the present situation of epidemic disease prevention team at village level of Wujiang Town,Ganzhou district,and summarized some practices on the selection,duty and management of animal epidemic prevention staff at village level.It also analyzed some details in the fulfillment of epidemic prevention rule,definitely responsibility and assisting their superior in carrying out prevention task.

  9. Uma abordagem ao estudo de epidemias de moléstias contagiosas: modelo conceitual baseado nas escalas espaciais e funcionais da propagação epidêmica An approach to the study of contagious disease epidemics: conceptual model based on spatial and functional scales of epidemic progression

    Directory of Open Access Journals (Sweden)

    Clovis K. Takiguti

    1986-06-01

    Full Text Available Propõe-se, uma nova abordagem para a solução do problema da metodologia padronizada, em epidemias. Consiste em um modelo conceitual, onde: (a Integram-se os componentes da epidemia de acordo com esse método amplamente utilizado por geógrafos, quando da difusão de inovações. Justifica-se pelo isomorfismo entre esta difusão e a disseminação de uma doença infecciosa, (b Essa sistemática tem em si, implícitos, os dados a serem colhidos no campo do surto epidêmico. Inclui, a intercorrelação dos elementos de composição do evento, permitindo a elucidação metódica (não simplesmente intuitiva do mecanismo da propagação do mesmo, (c O inter-relacionamento daqueles vários elementos, é feito racionalmente, pois são utilizadas inúmeras escalas espaciais (aspectos estáticos e funcionais (aspectos dinâmicos. A falha em identificar o conceito de escala (básico tem provocado muita confusão e, principalmente, evitado progressos importantes na análise epidêmica. Com efeito, essa não identificação da unidade de escala, tem prejudicado a padronização em epidemias.A new approach to the standardization of the study of epidemics is proposed. The approach proposed consists of a conceptual model where: (a the epidemic components are integrated according to models used by geographers in the study of innovation diffusion. This attitude is justified by the isomorphism between this diffusion and dissemination of an infectious disease; (b the model adopted takes into account the data to be collected in field work on epidemics. This permits a non-intuitive method for the elucidation of the mechanism of progression of epidemics, and (c the relationship between the several components is made rationally because of the use of some spatial scales (static view and some functional ones (dynamic view. The failure to identify the (basic concept of scale has provoked much confusion and has impeded important progress in the study of epidemics. As a

  10. Features of a clinical course of the acute respiratory diseases caused by adenoviruses of epidemic significant serotypes

    Directory of Open Access Journals (Sweden)

    N. I. L`vov

    2014-01-01

    Full Text Available The objective: To investigate etiological structure of adenoviral diseases in young people from organized groups and the clinical features of acute respiratory disease caused by different serotypes of adenovirus were identified.Materials and methods: A total 382 patients with adenovirusinfections were investigated. Virus isolation from nasopharyngeal swabs was carried out in cell cultures Vero, HeLa, Hep-2. Typing of adenoviruses was performed by virus neutralization test with polyclonal rabbit subtype specific sera. The average (M, standard deviation (SD and frequency of occurrence (% of clinical signs (respiratory and non-respiratory syndromes of pneumonia, protracted and recurrent course was calculated. Significance of the differences (p<0,05 of average frequency of cases compared to independent group of patients was evaluated by Student t-test and criterion φ2 (phi – square Fischer, respectively.Results: As result of investigation 199 adenovirus strains (52,1 % were isolated. 183 strains were serotyped: 64 (32,2 % – 3 serotype, 42 (21,1 % – 4 serotype, 38 (19,1 % – 7 serotype, 15 (7,5 % – 5 serotype, 11 (5,5 % – 21 serotype, 8 (4,0 % – 1 serotype, 3 (1,5 % – 2 serotype, 2 (1,0 % – 6 serotype. In assessing the features of the clinical course of adenoviral infection caused by the most actual serotypes (3, 4, 7 of adenovirus revealed that duration of diseases caused by serotype 7 was significantly longer and remained febrile fever (4,3±2,74 days, p<0,05, rhinitis (9,4±6,01 days, p<0,05, pharyngitis (7,9±2,87 days, p<0,05, laryngitis (7,3±2,87 days, p<0,05 and bronchitis (11,8±8,03 days, p<0,05, tonsillitis (63,0%, φ2=12,6, p<0,05, lymphadenopathy (63,0%, φ2=4,1, p<0,05, and pneumonia (34,2%, φ2=3,84, p<0,05 were registered significantly more frequently.Conclusion: The study showed that the adenoviruses of 3, 4 and 7 serotype have the greatest epidemiological significance. Clinical features

  11. Cooperative epidemics on multiplex networks

    CERN Document Server

    Azimi-Tafreshi, N

    2015-01-01

    The spread of one disease, in some cases, can stimulate the spreading of another infectious disease. Here, we treat analytically a symmetric co-infection model for spreading of two diseases on a 2-layer multiplex network. We allow layer overlapping, but we assume that each layer is random and locally loop-less. Infection with one of the diseases increases the probability to get infected by the other. Using generating function method, we calculate exactly the fraction of individuals infected with both diseases (so-called co-infected clusters) in the stationary state, as well as the epidemic spreading thresholds and the phase diagram of the model. With increasing cooperation, we observe a tricritical point and the type of transition changes from continuous to hybrid. Finally we compare the co-infected clusters in the case of co-operating diseases with the so-called viable clusters in networks with dependencies.

  12. Mathematical analysis and modeling of epidemics of rubber tree root diseases: Probability of infection of an individual tree

    Energy Technology Data Exchange (ETDEWEB)

    Chadoeuf, J.; Joannes, H.; Nandris, D.; Pierrat, J.C.

    1988-12-01

    The spread of root diseases in rubber tree (Hevea brasiliensis) due to Rigidoporus lignosus and Phellinus noxius was investigated epidemiologically using data collected every 6 month during a 6-year survey in a plantation. The aim of the present study is to see what factors could predict whether a given tree would be infested at the following inspection. Using a qualitative regression method we expressed the probability of pathogenic attack on a tree in terms of three factors: the state of health of the surrounding trees, the method used to clear the forest prior to planting, and evolution with time. The effects of each factor were ranked, and the roles of the various classes of neighbors were established and quantified. Variability between successive inspections was small, and the method of forest clearing was important only while primary inocula in the soil were still infectious. The state of health of the immediate neighbors was most significant; more distant neighbors in the same row had some effect; interrow spread was extremely rare. This investigation dealt only with trees as individuals, and further study of the interrelationships of groups of trees is needed.

  13. Modeling Epidemic Network Failures

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Fagertun, Anna Manolova

    2013-01-01

    the SID model’s behavior and impact on the network performance, as well as the severity of the infection spreading. The simulations are carried out in OPNET Modeler. The model provides an important input to epidemic connection recovery mechanisms, and can due to its flexibility and versatility be used......This paper presents the implementation of a failure propagation model for transport networks when multiple failures occur resulting in an epidemic. We model the Susceptible Infected Disabled (SID) epidemic model and validate it by comparing it to analytical solutions. Furthermore, we evaluate...

  14. 一起穿山甲疫情的病原分析%Pathogenic Analysis of A Disease Epidemic in Pangolins

    Institute of Scientific and Technical Information of China (English)

    陶立; 杨威; 闫鼎羽; 李军; 马春霞; 陈泽祥; 梁文汇; 阙腾程; 曾鹏; 李宝财

    2016-01-01

    In order to find out the cause of disease epidemic in raised pangolins,samples from two dead pan-golins were detected by bacterial isolation and PCR.Influenza virus,paramyxovirus or adenovirus virus could not be detected by PCR.Two bacterial strains were isolated from lungs of dead pangolins.Biochemi-cal tests,16 S rRNA sequence analysis of bacteria indicated that both isolates were Morganella morganii . Animal pathogenicity test suggested that the two isolates had strong pathogenic effect;while drug sensitiv-ity test showed that both isolates were highly sensitive to neomycin,spectinomycin and amikacin.%为了查明一起人工养殖穿山甲疫情的致病原因,应用病毒 PCR 检测和细菌分离的方法对2只前后病死穿山甲进行病原学检测。病毒 PCR 检测结果显示,未能从肺组织中检测到流感病毒、副黏病毒和腺病毒核酸。细菌分离结果表明,从2只病死穿山甲肺中各分离到1株优势菌株。细菌的生化试验、16 S rRNA 基因的序列分析表明,2株分离菌株均为摩氏摩根菌。小鼠的致病试验和分离菌的药敏试验结果表明,2株分离菌对小鼠有很强的致病作用,对新霉素、壮观霉素、阿米卡星高度敏感。

  15. The epidemic of Athens, 430 - 426 BC

    African Journals Online (AJOL)

    1998-01-01

    Jan 1, 1998 ... evidence, narrows down the many possibilities to epidemic typhus, plague, arboviral disease (e.g. Rift Valley fever) and smallpox. ... reviews have been published}" Instead of attempting to ... personal opinion about the origin of the plague, and the .... It was a previously unknown disease with an explosive.

  16. Can epidemics be non-communicable?

    DEFF Research Database (Denmark)

    Seeberg, Jens; Meinert, Lotte

    2015-01-01

    This article argues that the concept of communicability that is central to the distinction between communicable diseases (CDs) and noncommunicable diseases (NCDs) is poorly conceptualized. The epidemic spread of NCDs such as diabetes, depression, and eating disorders demonstrates that they are co...

  17. The new epidemic.

    Science.gov (United States)

    Allen, Jeanne V; Mellin, Grace C

    2014-03-01

    Editor's note: From its first issue in 1900 through to the present day, AJN has unparalleled archives detailing nurses' work and lives over the last century. These articles not only chronicle nursing's growth as a profession within the context of the events of the day, but they also reveal prevailing societal attitudes about women, health care, and human rights. Today's nursing school curricula rarely include nursing's history, but it's a history worth knowing. To this end, From the AJN Archives will be a frequent column, containing articles selected to fit today's topics and times.This month's article, from the November 1982 issue, is the first AJN article published on AIDS. It was early in the epidemic; only 608 cases of Kaposi's sarcoma and opportunistic infections had been reported to the Centers for Disease Control and Prevention-a mere trickle in the flood that was to come. Reading it now, aware of all we've learned since, we have a sense of how much we were fumbling around in the dark in those early days, searching for a cause and a cure, often going in wrong directions. The closest we had come to the true nature of the syndrome was an understanding that "life-style factors seem to be involved and the agent appears to be infectious." To read the complete article from our archives, go to http://bit.ly/1iswhZe.

  18. In Silico screening for functional candidates amongst hypothetical proteins

    DEFF Research Database (Denmark)

    Desler, Claus; Suravajhala, Prashanth; Sanderhoff, May

    2009-01-01

    BACKGROUND: The definition of a hypothetical protein is a protein that is predicted to be expressed from an open reading frame, but for which there is no experimental evidence of translation. Hypothetical proteins constitute a substantial fraction of proteomes of human as well as of other...... strategy where eukaryotic hypothetical proteins are sorted according to two criteria that can be reliably identified in silico: the presence of subcellular targeting signals and presence of characterized protein domains. To validate the selection strategy we applied it on a database of human hypothetical......, defined as hypothetical in 2006, have later been characterized as mitochondrial. CONCLUSION: Among the total amount of human proteins hypothetical in 2006, 21% have later been experimentally characterized and 6% of those have been shown to have a role in a mitochondrial context. In contrast, among...

  19. Urgent epidemic control mechanism for aviation networks

    KAUST Repository

    Peng, Chengbin

    2011-01-01

    In the current century, the highly developed transportation system can not only boost the economy, but also greatly accelerate the spreading of epidemics. While some epidemic diseases may infect quite a number of people ahead of our awareness, the health care resources such as vaccines and the medical staff are usually locally or even globally insufficient. In this research, with the network of major aviation routes as an example, we present a method to determine the optimal locations to allocate the medical service in order to minimize the impact of the infectious disease with limited resources. Specifically, we demonstrate that when the medical resources are insufficient, we should concentrate our efforts on the travelers with the objective of effectively controlling the spreading rate of the epidemic diseases. © 2011 Springer-Verlag Berlin Heidelberg.

  20. Inferring epidemic network topology from surveillance data.

    Science.gov (United States)

    Wan, Xiang; Liu, Jiming; Cheung, William K; Tong, Tiejun

    2014-01-01

    The transmission of infectious diseases can be affected by many or even hidden factors, making it difficult to accurately predict when and where outbreaks may emerge. One approach at the moment is to develop and deploy surveillance systems in an effort to detect outbreaks as timely as possible. This enables policy makers to modify and implement strategies for the control of the transmission. The accumulated surveillance data including temporal, spatial, clinical, and demographic information, can provide valuable information with which to infer the underlying epidemic networks. Such networks can be quite informative and insightful as they characterize how infectious diseases transmit from one location to another. The aim of this work is to develop a computational model that allows inferences to be made regarding epidemic network topology in heterogeneous populations. We apply our model on the surveillance data from the 2009 H1N1 pandemic in Hong Kong. The inferred epidemic network displays significant effect on the propagation of infectious diseases.

  1. The epidemic of Tuberculosis on vaccinated population

    Science.gov (United States)

    Syahrini, Intan; Sriwahyuni; Halfiani, Vera; Meurah Yuni, Syarifah; Iskandar, Taufiq; Rasudin; Ramli, Marwan

    2017-09-01

    Tuberculosis is an infectious disease which has caused a large number of mortality in Indonesia. This disease is caused by Mycrobacterium tuberculosis. Besides affecting lung, this disease also affects other organs such as lymph gland, intestine, kidneys, uterus, bone, and brain. This article discusses the epidemic of tuberculosis through employing the SEIR model. Here, the population is divided into four compartments which are susceptible, exposed, infected and recovered. The susceptible population is further grouped into two which are vaccinated group and unvaccinated group. The behavior of the epidemic is investigated through analysing the equilibrium of the model. The result shows that administering vaccine to the susceptible population contributes to the reduction of the tuberculosis epidemic rate.

  2. Dynamics of beneficial epidemics

    CERN Document Server

    Berdahl, Andrew; De Bacco, Caterina; Dumas, Marion; Ferdinand, Vanessa; Grochow, Joshua A; Hébert-Dufresne, Laurent; Kallus, Yoav; Kempes, Christopher P; Kolchinsky, Artemy; Larremore, Daniel B; Libby, Eric; Power, Eleanor A; Stern, Caitlin A; Tracey, Brendan

    2016-01-01

    Pathogens can spread epidemically through populations. Beneficial contagions, such as viruses that enhance host survival or technological innovations that improve quality of life, also have the potential to spread epidemically. How do the dynamics of beneficial biological and social epidemics differ from those of detrimental epidemics? We investigate this question using three theoretical approaches as well as an empirical analysis of concept propagation. First, in evolutionary models, we show that a beneficial horizontally-transmissible element, such as viral DNA, spreads super-exponentially through a population, substantially more quickly than a beneficial mutation. Second, in an epidemiological social network approach, we show that infections that cause increased connectivity lead to faster-than-exponential fixation in the population. Third, in a sociological model with strategic rewiring, we find that preferences for increased global infection accelerate spread and produce super-exponential fixation rates,...

  3. Epidemic features affecting the performance of outbreak detection algorithms

    Directory of Open Access Journals (Sweden)

    Kuang Jie

    2012-06-01

    Full Text Available Abstract Background Outbreak detection algorithms play an important role in effective automated surveillance. Although many algorithms have been designed to improve the performance of outbreak detection, few published studies have examined how epidemic features of infectious disease impact on the detection performance of algorithms. This study compared the performance of three outbreak detection algorithms stratified by epidemic features of infectious disease and examined the relationship between epidemic features and performance of outbreak detection algorithms. Methods Exponentially weighted moving average (EWMA, cumulative sum (CUSUM and moving percentile method (MPM algorithms were applied. We inserted simulated outbreaks into notifiable infectious disease data in China Infectious Disease Automated-alert and Response System (CIDARS, and compared the performance of the three algorithms with optimized parameters at a fixed false alarm rate of 5% classified by epidemic features of infectious disease. Multiple linear regression was adopted to analyse the relationship of the algorithms’ sensitivity and timeliness with the epidemic features of infectious diseases. Results The MPM had better detection performance than EWMA and CUSUM through all simulated outbreaks, with or without stratification by epidemic features (incubation period, baseline counts and outbreak magnitude. The epidemic features were associated with both sensitivity and timeliness. Compared with long incubation, short incubation had lower probability (β* = −0.13, P  Conclusions The results of this study suggest that the MPM is a prior algorithm for outbreak detection and differences of epidemic features in detection performance should be considered in automatic surveillance practice.

  4. Can epidemics be non-communicable?

    DEFF Research Database (Denmark)

    Seeberg, Jens; Meinert, Lotte

    2015-01-01

    This article argues that the concept of communicability that is central to the distinction between communicable diseases (CDs) and noncommunicable diseases (NCDs) is poorly conceptualized. The epidemic spread of NCDs such as diabetes, depression, and eating disorders demonstrates that they are co......This article argues that the concept of communicability that is central to the distinction between communicable diseases (CDs) and noncommunicable diseases (NCDs) is poorly conceptualized. The epidemic spread of NCDs such as diabetes, depression, and eating disorders demonstrates...... that they are communicable, even if they are not infectious. We need to more critically explore how they might be communicable in specific environments. All diseases with epidemic potential, we argue, should be assumed to be commun icable in a broader sense, and that the underlying medical distinction between infectious...... and noninfectious diseases confuses our understanding of NCD epidemics when these categories are treated as synonymous with ‘communicable’ and ‘noncommunicable’ diseases, respectively. The dominant role accorded to the concept of ‘lifestyle’, with its focus on individual responsibility, is part of the problem...

  5. Mutual Feedback Between Epidemic Spreading and Information Diffusion

    CERN Document Server

    Zhan, Xiu-Xiu; Zhou, Ge; Zhang, Zi-Ke; Sun, Gui-Quan; Zhu, Jonathan J H

    2015-01-01

    The impact that information diffusion has on epidemic spreading has recently attracted much attention. As a disease begins to spread in the population, information about the disease is transmitted to others, which in turn has an effect on the spread of disease. In this paper, using empirical results of the propagation of H7N9 and information about the disease, we clearly show that the spreading dynamics of the two-types of processes influence each other. We build a mathematical model in which both types of spreading dynamics are described using the SIS process in order to illustrate the influence of information diffusion on epidemic spreading. Both the simulation results and the pairwise analysis reveal that information diffusion can increase the threshold of an epidemic outbreak, decrease the final fraction of infected individuals and significantly decrease the rate at which the epidemic propagates. Additionally, we find that the multi-outbreak phenomena of epidemic spreading, along with the impact of inform...

  6. [The history of cholera epidemics in Israel].

    Science.gov (United States)

    Schwartz, Eli; Bar-El, Dan; Schur, Natan

    2005-05-01

    During the years 1831-1918 Israel (Palestine at that time) suffered from repeated cholera epidemics. The cholera epidemics were the major cause of severe health crisis among the population. The epidemics were transmitted by returening pilgrims returning from Mecca and, during the first world War, by the Turkish soldiers crossing the country. The disease caused panic amongst the population due to its high mortality rate. Quarantine which was the major measure taken by the government at that time was repeatedly broken by people trying to escape from the affected area. During the epidemic of 1902, patients were even reluctant to be treated by physicians as they were blamed for causing death. On the other hand, cholera was a major trigger for maintaining a better sanitation and establishing social relief systems within the communities. Most of the epidemics occurred in the old cities such as Jerusalem, Tiberia and Jaffa where infrastructure was inadequate. Cholera outbreaks were the trigger to build outside the old cities as in case of Jerusalem in which after the 1865 outbreak the city was expanded outside the walls. Since the end of the Ottoman period in Israel, cholera epidemics ceased, and except for very small occeasional small outbreaks, cholera is not seen here more.

  7. Untangling the Interplay between Epidemic Spread and Transmission Network Dynamics.

    Directory of Open Access Journals (Sweden)

    Christel Kamp

    Full Text Available The epidemic spread of infectious diseases is ubiquitous and often has a considerable impact on public health and economic wealth. The large variability in the spatio-temporal patterns of epidemics prohibits simple interventions and requires a detailed analysis of each epidemic with respect to its infectious agent and the corresponding routes of transmission. To facilitate this analysis, we introduce a mathematical framework which links epidemic patterns to the topology and dynamics of the underlying transmission network. The evolution, both in disease prevalence and transmission network topology, is derived from a closed set of partial differential equations for infections without allowing for recovery. The predictions are in excellent agreement with complementarily conducted agent-based simulations. The capacity of this new method is demonstrated in several case studies on HIV epidemics in synthetic populations: it allows us to monitor the evolution of contact behavior among healthy and infected individuals and the contributions of different disease stages to the spreading of the epidemic. This gives both direction to and a test bed for targeted intervention strategies for epidemic control. In conclusion, this mathematical framework provides a capable toolbox for the analysis of epidemics from first principles. This allows for fast, in silico modeling--and manipulation--of epidemics and is especially powerful if complemented with adequate empirical data for parameterization.

  8. Detecting nonlinearity and chaos in epidemic data

    Energy Technology Data Exchange (ETDEWEB)

    Ellner, S.; Gallant, A.R. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Statistics; Theiler, J. [Santa Fe Inst., NM (United States)]|[Los Alamos National Lab., NM (United States)

    1993-08-01

    Historical data on recurrent epidemics have been central to the debate about the prevalence of chaos in biological population dynamics. Schaffer and Kot who first recognized that the abundance and accuracy of disease incidence data opened the door to applying a range of methods for detecting chaos that had been devised in the early 1980`s. Using attractor reconstruction, estimates of dynamical invariants, and comparisons between data and simulation of SEIR models, the ``case for chaos in childhood epidemics`` was made through a series of influential papers beginning in the mid 1980`s. The proposition that the precise timing and magnitude of epidemic outbreaks are deterministic but chaotic is appealing, since it raises the hope of finding determinism and simplicity beneath the apparently stochastic and complicated surface of the data. The initial enthusiasm for methods of detecting chaos in data has been followed by critical re-evaluations of their limitations. Early hopes of a ``one size fits all`` algorithm to diagnose chaos vs. noise in any data set have given way to a recognition that a variety of methods must be used, and interpretation of results must take into account the limitations of each method and the imperfections of the data. Our goals here are to outline some newer methods for detecting nonlinearity and chaos that have a solid statistical basis and are suited to epidemic data, and to begin a re-evaluation of the claims for nonlinear dynamics and chaos in epidemics using these newer methods. We also identify features of epidemic data that create problems for the older, better known methods of detecting chaos. When we ask ``are epidemics nonlinear?``, we are not questioning the existence of global nonlinearities in epidemic dynamics, such as nonlinear transmission rates. Our question is whether the data`s deviations from an annual cyclic trend (which would reflect global nonlinearities) are described by a linear, noise-driven stochastic process.

  9. Fractional Derivatives in Dengue Epidemics

    Science.gov (United States)

    Pooseh, Shakoor; Rodrigues, Helena Sofia; Torres, Delfim F. M.

    2011-09-01

    We introduce the use of fractional calculus, i.e., the use of integrals and derivatives of non-integer (arbitrary) order, in epidemiology. The proposed approach is illustrated with an outbreak of dengue disease, which is motivated by the first dengue epidemic ever recorded in the Cape Verde islands off the coast of west Africa, in 2009. Numerical simulations show that in some cases the fractional models fit better the reality when compared with the standard differential models. The classical results are obtained as particular cases by considering the order of the derivatives to take an integer value.

  10. Fractional derivatives in Dengue epidemics

    CERN Document Server

    Pooseh, Shakoor; Torres, Delfim F M

    2011-01-01

    We introduce the use of fractional calculus, i.e., the use of integrals and derivatives of non-integer (arbitrary) order, in epidemiology. The proposed approach is illustrated with an outbreak of dengue disease, which is motivated by the first dengue epidemic ever recorded in the Cape Verde islands off the coast of west Africa, in 2009. Numerical simulations show that in some cases the fractional models fit better the reality when compared with the standard differential models. The classical results are obtained as particular cases by considering the order of the derivatives to take an integer value.

  11. Space-Time Point Pattern Analysis of Flavescence Dorée Epidemic in a Grapevine Field: Disease Progression and Recovery

    Science.gov (United States)

    Maggi, Federico; Bosco, Domenico; Galetto, Luciana; Palmano, Sabrina; Marzachì, Cristina

    2017-01-01

    Analyses of space-time statistical features of a flavescence dorée (FD) epidemic in Vitis vinifera plants are presented. FD spread was surveyed from 2011 to 2015 in a vineyard of 17,500 m2 surface area in the Piemonte region, Italy; count and position of symptomatic plants were used to test the hypothesis of epidemic Complete Spatial Randomness and isotropicity in the space-time static (year-by-year) point pattern measure. Space-time dynamic (year-to-year) point pattern analyses were applied to newly infected and recovered plants to highlight statistics of FD progression and regression over time. Results highlighted point patterns ranging from disperse (at small scales) to aggregated (at large scales) over the years, suggesting that the FD epidemic is characterized by multiscale properties that may depend on infection incidence, vector population, and flight behavior. Dynamic analyses showed moderate preferential progression and regression along rows. Nearly uniform distributions of direction and negative exponential distributions of distance of newly symptomatic and recovered plants relative to existing symptomatic plants highlighted features of vector mobility similar to Brownian motion. These evidences indicate that space-time epidemics modeling should include environmental setting (e.g., vineyard geometry and topography) to capture anisotropicity as well as statistical features of vector flight behavior, plant recovery and susceptibility, and plant mortality. PMID:28111581

  12. Preschool Children's Judgments about Hypothetical and Actual Transgressions.

    Science.gov (United States)

    Smetana, Judith G.; And Others

    1993-01-01

    Examined three and four year olds' judgments about transgressions. Children judged moral transgressions to be more serious, punishable, and wrong than conventional transgressions; hypothetical transgressions to be more wrong independent of rules than actual transgressions; and hypothetical moral transgressions to be more independent of rules than…

  13. Vaccination intervention on epidemic dynamics in networks

    CERN Document Server

    Peng, Xiao-Long; Fu, Xinchu; Zhou, Tao

    2013-01-01

    Vaccination is an important measure available for preventing or reducing the spread of infectious diseases. In this paper, an epidemic model including susceptible, infected, and imperfectly vaccinated compartments is studied on Watts-Strogatz small-world, Barab\\'asi-Albert scale-free, and random scale-free networks. The epidemic threshold and prevalence are analyzed. For small-world networks, the effective vaccination intervention is suggested and its influence on the threshold and prevalence is analyzed. For scale-free networks, the threshold is found to be strongly dependent both on the effective vaccination rate and on the connectivity distribution. Moreover, so long as vaccination is effective, it can linearly decrease the epidemic prevalence in small-world networks, whereas for scale-free networks it acts exponentially. These results can help in adopting pragmatic treatment upon diseases in structured populations.

  14. Epidemic Spreading in Contact Networks Based on Exposure Level

    Institute of Scientific and Technical Information of China (English)

    DUAN Wen-Qi; CHEN Zhong; LIU Zeng-Rong

    2006-01-01

    @@ Most epidemic models for the spread of diseases in contact networks take the assumption of the infected probability of a susceptible agent dependent on its absolute number of infectious neighbours. We introduce a new epidemic model in which the infected probability of a susceptible agent in contact networks depends not on its degree but on its exposure level. We find that effective average infection rate (λ) (i.e., the average number of infections produced by a single contact between infected individuals and susceptible individuals) has an epidemic threshold (λ)c = 1, which is related to recovery rate, epidemic mechanisms and topology of contact network. Furthermore,we show the dominating importance of epidemic mechanisms in determining epidemic patterns and discussed the implications of our model for infection control policy.

  15. 流行性脑脊髓膜炎疾病负担研究综述%Review of researches on disease burden due to epidemic cerebrospinal meningitis

    Institute of Scientific and Technical Information of China (English)

    王萌

    2012-01-01

    Epidemic cerebrospinal meningitis (ECM)is an infectious disease which attacks acutely,and makes progression rapidly. It will lead to death if improper treatment or not in time. Of the survivors, about 10-15% are with long-term sequelae,such as nerve deafness,blindness,oculomotor nerve palsy,paralysis of limbs,intellectual and emotional change,mental abnormality and so on. For the single ECM,there are not many researches of long-term sequelae. But the ECM is belonging to purulent meningitis,and it is a common type of bacterial meningitis. The research data of purulent meningitis or bacterial meningitis has important significance to understand the harm of the ECM deeply. There are lack of long-term follow-up data of ECM, and its mortality, morbidity or occurrence rate of sequelae is unknown; meanwhile, there is lack of the economic burden data of specific ECM of domestic and international.%流行性脑脊髓膜炎发病急,进展快,若救治不当或不及时易导致死亡.幸存者中,大约有10%~15%的人伴有长期的后遗症,如神经性耳聋、失明、动眼神经麻痹、四肢瘫痪、智力和情志改变、精神异常等.就流脑此单病种而言,长期后遗症方面的研究数据不多.但流脑属于化脓性脑膜炎,同时也是细菌性脑膜炎中常见的一种.参考化脓性脑膜炎或细菌性脑膜炎的研究数据对加深认识流脑的危害有重要意义.流脑缺乏长期随诊资料,病死率、致残率或后遗症发生率情况不详;同时,国内外缺乏针对流脑这一具体病种的经济负担数据.

  16. Epidemic situation of sexually transmitted disease in Nanjing City, 2006-2009%南京市2006~2009年性病疫情分析

    Institute of Scientific and Technical Information of China (English)

    王琛琛; 张敏; 吴苏姝; 郭璐

    2012-01-01

    OBJECTIVE To investigate the epidemic situation of sexually transmitted diseases (STDs) in Nanjing city, and to initiate preventive strategy against (STDs). METHODS The data of (STDs) were collected from medical institutions and direct network reporting system. RESULTS The annually average incidence of (STDs) was 90.33/100 000 and the incidence ratio of male to female was 1 : 0.57 in 2006-2009. Most of the patients were young adults, aged 20-39 years old (60.45%). The workers, unemployed and peasants were the main reported occupations of the patients (54.38%). From 2006-2009, the incidence of syphilis were 27.74/100 000, 29.86/100 000, 36.89/100 000 and 45.97/100 000 in each year, respectively. CONCLUSION The cases of STDs have been decreasing steadily in Nanjing in the recent past years. However, increasing trend is observed in cases of syphilis.%目的 了解南京市性传播疾病流行病学特征,为更好的制定有效防制措施提供科学依据.方法 对南京市各医疗和网络直报单位上报的2006~2009年度性病的疫情资料进行分析.结果 2006~2009年期间南京市性传播疾病年的年度平均发病率为90.33/10万.男女之比为1:0.57,年龄主要集中在20~39岁(60.45%).职业以工人、家务及待业人员和农民为主(54.38%).2006~2009年度梅毒的年发病率分别为27.74/10万、29.86/10万、36.89/10万、45.97/10万.结论 南京市性传播疾病的年发病率总体上呈平稳下降趋势,但梅毒的发病率则呈显著上升趋势.

  17. Event history analysis of dengue fever epidemic and inter-epidemic spells in Barbados, Brazil, and Thailand.

    Science.gov (United States)

    Parker, Daniel; Holman, Darryl

    2012-11-01

    This study investigated meteorological and demographic factors affecting the length of dengue fever epidemics and the length of time between epidemics in Barbados, Brazil, and Thailand. Region-specific meteorological and demographic data were collected for 104 sites from public sources. Fixed effects piecewise logistic event history analysis was used to quantify the effects of time-varying covariates on the duration of inter-epidemic spells and for the duration of epidemics. Mean monthly temperature was the most important factor affecting the duration of both inter-epidemic spells (β=0.543; confidence interval (CI) 0.4954, 0.5906) and epidemic spells (β=-0.648; CI -0.7553, -0.5405). Drought conditions increased the time between epidemics. Increased temperature hastened the onset of an epidemic, and during an epidemic, higher mean temperature increased the duration of the epidemic. By using a duration analysis, this study offers a novel approach for investigating the dynamics of dengue fever epidemiology. Furthermore, these results offer new insights into prior findings of a correlation between temperature and the geographic range and vector efficiency of dengue fever. Copyright © 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  18. WKB theory of epidemic fade-out in stochastic populations

    OpenAIRE

    Meerson, Baruch; Sasorov, Pavel V.

    2009-01-01

    Stochastic effects may cause fade-out of an infectious disease in a population immediately after an epidemic outbreak. We develop WKB theory to determine the most probable path of the system toward epidemic fade-out and to evaluate the fade-out probability. The most probable path is an instanton-like orbit in the phase space of the underlying Hamiltonian flow.

  19. 奶牛四种流产性疾病的流行现状及疫苗研究进展%Research Progress on the Vaccine and Epidemic Situation of Four Types of Abortion Disease in Dairy Cattle

    Institute of Scientific and Technical Information of China (English)

    李前勇; 张德志; 徐蓉; 吴艳秋; 詹飞; 吴润彪

    2014-01-01

    奶牛布氏杆菌病、传染性鼻气管炎、病毒性腹泻-黏膜病及新孢子虫病是导致我国奶牛流产发病比例升高的主要疾病,有效防控这四种疾病一直是世界关注的重点之一。本文对上述四种疾病的流行现状及疫苗研究进展进行了综述。%The four diseases including Bovine brucellosis, Bovine infection rhinotracheitis, Bovine viral diarrhea and Bovine neosporiasis are the main diseases that causing cow′s abortion. Pre-vention and control of these four diseases effectively have become one of the focuses. In this paper, research progress on the vaccine and epidemic situation of these four diseases had been reviewed.

  20. Configuring the autism epidemic

    DEFF Research Database (Denmark)

    Christensen, Fie Lund Lindegaard; Seeberg, Jens

    2017-01-01

    Autism has been described as an epidemic, but this claim is contested and may point to an awareness epidemic, i.e. changes in the definition of what autism is and more attention being invested in diagnosis leading to a rise in registered cases. The sex ratio of children diagnosed with autism...... is skewed in favour of boys, and girls with autism tend to be diagnosed much later than boys. Building and further developing the notion of ‘configuration’ of epidemics, this article explores the configuration of autism in Denmark, with a particular focus on the health system and social support to families...... with children diagnosed with autism, seen from a parental perspective. The article points to diagnostic dynamics that contribute to explaining why girls with autism are not diagnosed as easily as boys. We unfold these dynamics through the analysis of a case of a Danish family with autism....

  1. The Epidemics of Corruption

    CERN Document Server

    Blanchard, P; Krüger, T; Martin, P; Blanchard, Ph.

    2005-01-01

    We study corruption as a generalized epidemic process on the graph of social relationships. The main difference to classical epidemic processes is the strong nonlinear dependence of the transmission probability on the local density of corruption and the mean field influence of the overall corruption in the society. Network clustering and the degree-degree correlation play an essential role in corruption dynamics. We discuss phase transitions, the influence of the graph structure and the implications for epidemic control. Structural and dynamical arguments are given why strongly hierarchically organized societies like systems with dictatorial tendency are more vulnerable to corruption than democracies. A similar type of modelling can be applied to other social contagion spreading processes like opinion formation, doping usage, social disorders or innovation dynamics.

  2. Stating the Epidemic and Controll of Banana Blight According to Principle of Disease Tetra-angle%根据病害四角原理阐述香蕉枯萎病流行与防控

    Institute of Scientific and Technical Information of China (English)

    文衍堂; 谢昌平; 贺春萍; 胡美姣; 杨波

    2012-01-01

    According to principle of disease tetra-angle, relationship between human, host, pathogen and environment condition, stale the epidemic and control engineering of Banana blight caused by Fusarium oxysporum f. sp. cubense.%根据病害四角原理,即人、寄主植物、病原物和环境条件四方面的关系,阐述由尖镰孢古巴专化型弓致香蕉枯萎病流行与防控工程。

  3. The Prescription Opioid Pain Medication Overdose Epidemic

    Centers for Disease Control (CDC) Podcasts

    2016-04-19

    Overdose related to prescription opioids has become an epidemic. This podcast discusses the risks of this type of drug sometimes used to treat pain, and how to protect yourself. .  Created: 4/19/2016 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 4/19/2016.

  4. Social epidemics in the aftermath of disasters.

    NARCIS (Netherlands)

    IJzermans, C.J.

    2002-01-01

    Issue/problem: After disasters, terrorist attacks and wars social epidemics of medically unexplained physical symptoms/syndromes (ups) are often seen. In modern times people feel more vulnerable and especially under pressure of those incidents, everyday symptoms are interpreted as disease and causal

  5. Social epidemics in the aftermath of disasters.

    NARCIS (Netherlands)

    IJzermans, C.J.

    2002-01-01

    Issue/problem: After disasters, terrorist attacks and wars social epidemics of medically unexplained physical symptoms/syndromes (ups) are often seen. In modern times people feel more vulnerable and especially under pressure of those incidents, everyday symptoms are interpreted as disease and

  6. Nine challenges for deterministic epidemic models

    DEFF Research Database (Denmark)

    Roberts, Mick G; Andreasen, Viggo; Lloyd, Alun;

    2015-01-01

    , infections with time-varying infectivity, and those where superinfection is possible. We then consider the need for advances in spatial epidemic models, and draw attention to the lack of models that explore the relationship between communicable and non-communicable diseases. The final two challenges concern...

  7. Epidemic and power in imperial Recife

    Directory of Open Access Journals (Sweden)

    Rosilene Gomes Farias

    2016-06-01

    Full Text Available In 1856, during the cholera epidemic that hit Recife, actions were implemented to prevent the disease, which presupposed the social control of the poorest sections of the population. The article discusses how these actions demonstrate the power relations involving public and medical authorities in Recife of the Nineteenth Century.

  8. Epidemic Models for SARS and Measles

    Science.gov (United States)

    Rozema, Edward

    2007-01-01

    Recent events have led to an increased interest in emerging infectious diseases. This article applies various deterministic models to the SARS epidemic of 2003 and a measles outbreak in the Netherlands in 1999-2000. We take a historical approach beginning with the well-known logistic curve and a lesser-known extension popularized by Pearl and Reed…

  9. Social epidemics in the aftermath of disasters.

    NARCIS (Netherlands)

    IJzermans, C.J.

    2002-01-01

    Issue/problem: After disasters, terrorist attacks and wars social epidemics of medically unexplained physical symptoms/syndromes (ups) are often seen. In modern times people feel more vulnerable and especially under pressure of those incidents, everyday symptoms are interpreted as disease and causal

  10. In Silico screening for functional candidates amongst hypothetical proteins

    Directory of Open Access Journals (Sweden)

    Sanderhoff May

    2009-09-01

    Full Text Available Abstract Background The definition of a hypothetical protein is a protein that is predicted to be expressed from an open reading frame, but for which there is no experimental evidence of translation. Hypothetical proteins constitute a substantial fraction of proteomes of human as well as of other eukaryotes. With the general belief that the majority of hypothetical proteins are the product of pseudogenes, it is essential to have a tool with the ability of pinpointing the minority of hypothetical proteins with a high probability of being expressed. Results Here, we present an in silico selection strategy where eukaryotic hypothetical proteins are sorted according to two criteria that can be reliably identified in silico: the presence of subcellular targeting signals and presence of characterized protein domains. To validate the selection strategy we applied it on a database of human hypothetical proteins dating to 2006 and compared the proteins predicted to be expressed by our selecting strategy, with their status in 2008. For the comparison we focused on mitochondrial proteins, since considerable amounts of research have focused on this field in between 2006 and 2008. Therefore, many proteins, defined as hypothetical in 2006, have later been characterized as mitochondrial. Conclusion Among the total amount of human proteins hypothetical in 2006, 21% have later been experimentally characterized and 6% of those have been shown to have a role in a mitochondrial context. In contrast, among the selected hypothetical proteins from the 2006 dataset, predicted by our strategy to have a mitochondrial role, 53-62% have later been experimentally characterized, and 85% of these have actually been assigned a role in mitochondria by 2008. Therefore our in silico selection strategy can be used to select the most promising candidates for subsequent in vitro and in vivo analyses.

  11. Epidemic spreading with immunization on bipartite networks

    CERN Document Server

    Tanimoto, Shinji

    2011-01-01

    Bipartite networks are composed of two types of nodes and there are no links between nodes of the same type. Thus the study of epidemic spread and control on such networks is relevant to sexually transmitted diseases (STDs). When entire populations of two types cannot be immunized and the effect of immunization is not perfect, we have to consider the targeted immunization with immunization rates. We derive the epidemic thresholds of SIR and SIS models with immunization and illustrate the results with STDs on heterosexual contact networks.

  12. Epidemics: Lessons from the past and current patterns of response

    Science.gov (United States)

    Martin, Paul

    2008-09-01

    Hippocrates gave the term 'epidemic' its medical meaning. From antiquity to modern times, the meaning of the word epidemic has continued to evolve. Over the centuries, researchers have reached an understanding of the varying aspects of epidemics and have tried to combat them. The role played by travel, trade, and human exchanges in the propagation of epidemic infectious diseases has been understood. In 1948, the World Health Organization was created and given the task of advancing ways of combating epidemics. An early warning system to combat epidemics has been implemented by the WHO. The Global Outbreak Alert and Response Network (GOARN) is collaboration between existing institutions and networks that pool their human and technical resources to fight outbreaks. Avian influenza constitutes currently the most deadly epidemic threat, with fears that it could rapidly reach pandemic proportions and put several thousands of lives in jeopardy. Thanks to the WHO's support, most of the world's countries have mobilised and implemented an 'Action Plan for Pandemic Influenza'. As a result, most outbreaks of the H5N1 avian flu virus have so far been speedily contained. Cases of dengue virus introduction in countries possessing every circumstance required for its epidemic spread provide another example pertinent to the prevention of epidemics caused by vector-borne pathogens.

  13. 新疆周边国家主要传染病疫情及传入的风险分析%The epidemic situation of main infectious diseases in Xinjiang neighboring countries and the risk analysis transmitting into Xinjiang

    Institute of Scientific and Technical Information of China (English)

    艾克塔古丽安外尔江; 刘金宝; 何冰

    2014-01-01

    Objective To understand the epidemic situation of main infectious diseases in Xinjiang neighbor‐ing countries and the risk of transmitting into Xinjiang .Methods Collected and analyzed the main infec‐tious diseases cases in Xinjiang neighboring countries ,w hich have reported to World Health Organization in recent years .Results The serious infectious diseases spreading in Xinjiang neighboring countries are Cholera ,Plague ,poliomyelitis ,AIDS ,Tuberculosis and Malaria .These infectious diseases are more seri‐ous epidemic in India ,Afghanistan and Pakistan .Mongolia has reported plague cases every year .Conclu‐sion The infectious diseases surveillance should be strengthened at frontier ports ,so as to prevent the in‐fectious diseases into of Xinjiang .%目的:了解新疆周边国家主要传染病流行情况及传入新疆地区的风险。方法资料来源于世界卫生组织报告的新疆周边国家主要传染病病例数据资料,并对其进行统计学分析。结果新疆周边国家流行较为严重的传染病有霍乱、鼠疫、脊髓灰质炎、艾滋病、结核病、疟疾等。这几种传染病在印度、阿富汗、巴基斯坦等国家流行较严重。蒙古几乎每年都有鼠疫病例。结论必须加强口岸传染病监测,防止传染病传入新疆。

  14. Epidemics of mold poisoning past and present.

    Science.gov (United States)

    Meggs, William J

    2009-01-01

    Molds are ubiquitous throughout the biosphere of planet earth and cause infectious, allergic, and toxic diseases. Toxic diseases arise from exposure to mycotoxins produced by molds. Throughout history, there have been a number of toxic epidemics associated with exposure to mycotoxins. Acute epidemics of ergotism are caused by consumption of grain infested by fungi of the genus Claviceps, which produce the bioactive amine ergotamine that mimics the neurotransmitters norepinephrine, serotonin, and dopamine. Acute aflatoxin outbreaks have occurred from ingestion of corn stored in damp conditions that potentiate growth of the molds of the species Aspergillus. Contemporary construction methods that use cellulose substrates such as fiber board and indoor moisture have caused an outbreak of contaminated buildings with Stachybotrys chartarum, with the extent of health effects still a subject of debate and ongoing research. This article reviews several of the more prominent epidemics and discusses the nature of the toxins. Two diseases that were leading causes of childhood mortality in England in the 1970s and vanished with changing dietary habits, putrid malignant fever, and slow nervous fever were most likely toxic mold epidemics.

  15. Construction of the Monitoring Station for Epidemic Diseases and Bird Monitoring in South Anhui%皖南疫源疫病监测站的建设与鸟类监测

    Institute of Scientific and Technical Information of China (English)

    赵融

    2015-01-01

    根据皖南鸟类的分布和活动规律,合理布局建设皖南鸟类监测站,对皖南山区鸟类疫源疫病进行监测,构建长效防控预警机制,为有效保护濒危珍稀鸟类、保护物种多样性、防止野生鸟类疫源疫病向畜禽及人类传播蔓延、维护地方生态安全做出应有的贡献.%The South Anhui bird monitoring station should be rationally laid out and constructed according to the distribution and activity regularities of birds in South Anhui to monitor bird epidemic diseases in mountainous areas of South Anhui and establish the long-term control and early warning mechanism, making contributions to effectively protecting endangered and rare birds and biodiversity, protecting spread of wild bird epidemic diseases to livestock, poultry and humans and maintaining the local ecological security.

  16. Analysis on the epidemic factors of natural infectious focus disease and arbo infectious disease in Qianxi county%迁西县自然疫源性和虫媒传染病流行因素分析

    Institute of Scientific and Technical Information of China (English)

    陈晓东; 刘春燕; 陈淑君

    2012-01-01

    Objective To analyze the morbidity status and influencing factors of natural infectious focus diseases and arbo infectious diseases from January 2005 to June 2011 , and provide scientific basis for prevention and control the disease incidence and spread. Method Descriptive epidemiological method was used for analyzing the data and Excel 2003 software was used for statistics the data. Results 6 kinds 42 cases of infectious disease of natural infectious focus disease and arbo infectious disease were reported through directly network from 2005. 01 to 2011. 06 in Qianxi county, which including Rabies ( 2 cases) , Hemorrhagic fever with renal syndrome ( 25 cases) , Brucellosis ( 5 cases) , Typhus ( 8 cases) , Epidemic encephalitis B ( 1 cases) , Malaria (1 cases) . Among them, 2 were dead, the annual average incidence rate was 1. 61/100 000 and the fatality rate was 4. 76%. Climate warming, ecological environment change, rapid development of animal husbandry industry and propaganda and education shortage of disease prevention and cure were important impact factors of the occurrence and spread of natural infectious focus diseases and arbo infectious diseases in qianxi county. Conclusions Climate and ecological environment variation monitoring should be strengthened, at the same time, monitoring the natural infectious focus disease and arbo infectious disease, virus carrier status of host animal, vector biology and crowd immune status too. Relevant departments should enhance the cooperation and developed the comprehensive control.%目的 通过分析迁西县2005年1月-2011年6月迁西县自然疫源性和虫媒传染病的发病情况和影响因素,为有效预防和控制自然疫源性和虫媒传染病的发生和蔓延提供科学依据.方法 应用描述性流行病学方法对资料进行分析,数据采用Excel2003软件进行统计.结果 迁西县2005年1月~2011年6月通过网络直报报告自然疫源性和虫媒传染病包括狂犬病(2

  17. An Epidemic of Cirrhosis in Danish Women Revisited

    DEFF Research Database (Denmark)

    Petersen, J.; Skinhøj, P.; Thorsen, Thorkil

    1986-01-01

    Between 1944 and 1947 the mortality statistics for the Danish population show an epidemic increase of liver diseases: subacute necrosis and cirrhosis. The epidemic only affected female mortality rates. Mortality due to cirrhosis remained at a higher rate for women than men until 1970 as a result...... of an excess mortality in the cohort of women who in 1945 were over the age of 45. Up to 1981 this group showed an excess of 4,000 fatalities. A reevaluation of medico-statistical data shows that the disease cannot be explained by the epidemic hepatitis occurring in 1942-1944 or by increased consumption...

  18. A hierarchical network approach for modeling Rift Valley fever epidemics with applications in North America.

    Directory of Open Access Journals (Sweden)

    Ling Xue

    Full Text Available Rift Valley fever is a vector-borne zoonotic disease which causes high morbidity and mortality in livestock. In the event Rift Valley fever virus is introduced to the United States or other non-endemic areas, understanding the potential patterns of spread and the areas at risk based on disease vectors and hosts will be vital for developing mitigation strategies. Presented here is a general network-based mathematical model of Rift Valley fever. Given a lack of empirical data on disease vector species and their vector competence, this discrete time epidemic model uses stochastic parameters following several PERT distributions to model the dynamic interactions between hosts and likely North American mosquito vectors in dispersed geographic areas. Spatial effects and climate factors are also addressed in the model. The model is applied to a large directed asymmetric network of 3,621 nodes based on actual farms to examine a hypothetical introduction to some counties of Texas, an important ranching area in the United States of America. The nodes of the networks represent livestock farms, livestock markets, and feedlots, and the links represent cattle movements and mosquito diffusion between different nodes. Cattle and mosquito (Aedes and Culex populations are treated with different contact networks to assess virus propagation. Rift Valley fever virus spread is assessed under various initial infection conditions (infected mosquito eggs, adults or cattle. A surprising trend is fewer initial infectious organisms result in a longer delay before a larger and more prolonged outbreak. The delay is likely caused by a lack of herd immunity while the infection expands geographically before becoming an epidemic involving many dispersed farms and animals almost simultaneously. Cattle movement between farms is a large driver of virus expansion, thus quarantines can be efficient mitigation strategy to prevent further geographic spread.

  19. A hierarchical network approach for modeling Rift Valley fever epidemics with applications in North America.

    Science.gov (United States)

    Xue, Ling; Cohnstaedt, Lee W; Scott, H Morgan; Scoglio, Caterina

    2013-01-01

    Rift Valley fever is a vector-borne zoonotic disease which causes high morbidity and mortality in livestock. In the event Rift Valley fever virus is introduced to the United States or other non-endemic areas, understanding the potential patterns of spread and the areas at risk based on disease vectors and hosts will be vital for developing mitigation strategies. Presented here is a general network-based mathematical model of Rift Valley fever. Given a lack of empirical data on disease vector species and their vector competence, this discrete time epidemic model uses stochastic parameters following several PERT distributions to model the dynamic interactions between hosts and likely North American mosquito vectors in dispersed geographic areas. Spatial effects and climate factors are also addressed in the model. The model is applied to a large directed asymmetric network of 3,621 nodes based on actual farms to examine a hypothetical introduction to some counties of Texas, an important ranching area in the United States of America. The nodes of the networks represent livestock farms, livestock markets, and feedlots, and the links represent cattle movements and mosquito diffusion between different nodes. Cattle and mosquito (Aedes and Culex) populations are treated with different contact networks to assess virus propagation. Rift Valley fever virus spread is assessed under various initial infection conditions (infected mosquito eggs, adults or cattle). A surprising trend is fewer initial infectious organisms result in a longer delay before a larger and more prolonged outbreak. The delay is likely caused by a lack of herd immunity while the infection expands geographically before becoming an epidemic involving many dispersed farms and animals almost simultaneously. Cattle movement between farms is a large driver of virus expansion, thus quarantines can be efficient mitigation strategy to prevent further geographic spread.

  20. Resilience of epidemics on networks

    CERN Document Server

    Lu, Dan; Zhang, Jiaquan; Wang, Huijuan; Li, Daqing

    2016-01-01

    Epidemic propagation on complex networks has been widely investigated, mostly with invariant parameters. However, the process of epidemic propagation is not always constant. Epidemics can be affected by various perturbations, and may bounce back to its original state, which is considered resilient. Here, we study the resilience of epidemics on networks, by introducing a different infection rate ${\\lambda_{2}}$ during SIS (susceptible-infected-susceptible) epidemic propagation to model perturbations (control state), whereas the infection rate is ${\\lambda_{1}}$ in the rest of time. Through simulations and theoretical analysis, we find that even for ${\\lambda_{2}<\\lambda_{c}}$, epidemics eventually could bounce back if control duration is below a threshold. This critical control time for epidemic resilience, i.e., ${cd_{max}}$ can be predicted by the diameter (${d}$) of the underlying network, with the quantitative relation ${cd_{max}\\sim d^{\\alpha}}$. Our findings can help to design a better mitigation stra...

  1. Recovery rate affects the effective epidemic threshold with synchronous updating

    CERN Document Server

    Shu, Panpan; Tang, Ming; Zhao, Pengcheng; Zhang, Yi-Cheng

    2016-01-01

    Accurate identification of effective epidemic threshold is essential for understanding epidemic dynamics on complex networks. The existing studies on the effective epidemic threshold of the susceptible-infected-removed (SIR) model generally assume that all infected nodes immediately recover after the infection process, which more or less does not conform to the realistic situation of disease. In this paper, we systematically study the effect of arbitrary recovery rate on the SIR spreading dynamics on complex networks. We derive the theoretical effective epidemic threshold and final outbreak size based on the edge-based compartmental theory. To validate the proposed theoretical predictions, extensive numerical experiments are implemented by using asynchronous and synchronous updating methods. When asynchronous updating method is used in simulations, recovery rate does not affect the final state of spreading dynamics. But with synchronous updating, we find that the effective epidemic threshold decreases with re...

  2. Epidemic Process over the Commute Network in a Metropolitan Area

    Science.gov (United States)

    Yashima, Kenta; Sasaki, Akira

    2014-01-01

    An understanding of epidemiological dynamics is important for prevention and control of epidemic outbreaks. However, previous studies tend to focus only on specific areas, indicating that application to another area or intervention strategy requires a similar time-consuming simulation. Here, we study the epidemic dynamics of the disease-spread over a commute network, using the Tokyo metropolitan area as an example, in an attempt to elucidate the general properties of epidemic spread over a commute network that could be used for a prediction in any metropolitan area. The model is formulated on the basis of a metapopulation network in which local populations are interconnected by actual commuter flows in the Tokyo metropolitan area and the spread of infection is simulated by an individual-based model. We find that the probability of a global epidemic as well as the final epidemic sizes in both global and local populations, the timing of the epidemic peak, and the time at which the epidemic reaches a local population are mainly determined by the joint distribution of the local population sizes connected by the commuter flows, but are insensitive to geographical or topological structure of the network. Moreover, there is a strong relation between the population size and the time that the epidemic reaches this local population and we are able to determine the reason for this relation as well as its dependence on the commute network structure and epidemic parameters. This study shows that the model based on the connection between the population size classes is sufficient to predict both global and local epidemic dynamics in metropolitan area. Moreover, the clear relation of the time taken by the epidemic to reach each local population can be used as a novel measure for intervention; this enables efficient intervention strategies in each local population prior to the actual arrival. PMID:24905831

  3. 温病初起治疗宜汗与忌汗之辨%On the Compatibility and Incompatibility of Inducing Diaphoresis at the Beginning of Epidemic Febrile Diseases

    Institute of Scientific and Technical Information of China (English)

    马扬; 刘兰林

    2001-01-01

    对温病初起治疗宜汗与忌汗的问题进行了讨论。认为忌汗是指忌辛温发汗,宜汗则指病在表,汗是热邪的重要出路,用“辛”使热邪从肌表得以宣泄。指出温病一面宜喜汗解,一面忌汗伤阴,理论说法不一,治疗难以把握。强调宜汗忌汗这对矛盾既是对立的,又是统一的,其结果同样是为了祛邪和保存津液。表明辨证地运用宜汗和忌汗,则能有效地提高温病的临床疗效。%The article discusses the compatibility and incompatibility ofinducing diaphoresis at the beginning of epidemic febrile diseases.Incompatibility of inducing diaphoresis means avoiding using drugs pungent in flavor and warm in property to induce diaphoresis. Yet,induction of diaphoresis is often used when disease is located in the exterior because perspiration is an important means of getting rid of pathogenic heat. Use of pungent and warm drugs can drive the pathogenic heat off the exterior of the body. On the one hand,inducing diaphoresis is good for epidemic febrile diseases because it helps to relieve exterior syndrome,but on the other hand, perspiration may cause impairment of yin. Contradictory views have been existing on this subject and it is very hard to decide clinically. The authors emphasized that compatibility and incompatibility of inducing diaphoresis is the unity of opposites. The aim is to eliminate the pathogenic factors and preserve body fluid. Dialectical use of compatibility and incompatibility of inducing diaphoresis may efficiently improve clinical efficacy in treating epidemic febrile diseases.

  4. Drought and epidemic typhus, central Mexico, 1655-1918.

    Science.gov (United States)

    Burns, Jordan N; Acuna-Soto, Rudofo; Stahle, David W

    2014-03-01

    Epidemic typhus is an infectious disease caused by the bacterium Rickettsia prowazekii and transmitted by body lice (Pediculus humanus corporis). This disease occurs where conditions are crowded and unsanitary. This disease accompanied war, famine, and poverty for centuries. Historical and proxy climate data indicate that drought was a major factor in the development of typhus epidemics in Mexico during 1655-1918. Evidence was found for 22 large typhus epidemics in central Mexico, and tree-ring chronologies were used to reconstruct moisture levels over central Mexico for the past 500 years. Below-average tree growth, reconstructed drought, and low crop yields occurred during 19 of these 22 typhus epidemics. Historical documents describe how drought created large numbers of environmental refugees that fled the famine-stricken countryside for food relief in towns. These refugees often ended up in improvised shelters in which crowding encouraged conditions necessary for spread of typhus.

  5. The effect of risk-taking behaviour in epidemic models.

    Science.gov (United States)

    Sega, L; Maxin, D; Eaton, L; Latham, A; Moose, A; Stenslie, S

    2015-01-01

    We study an epidemic model that incorporates risk-taking behaviour as a response to a perceived low prevalence of infection that follows from the administration of an effective treatment or vaccine. We assume that knowledge about the number of infected, recovered and vaccinated individuals has an effect in the contact rate between susceptible and infectious individuals. We show that, whenever optimism prevails in the risk behaviour response, the fate of an epidemic may change from disease clearance to disease persistence. Moreover, under certain conditions on the parameters, increasing the efficiency of vaccine and/or treatment has the unwanted effect of increasing the epidemic reproductive number, suggesting a wider range of diseases may become endemic due to risk-taking alone. These results indicate that the manner in which treatment/vaccine effectiveness is advertised can have an important influence on how the epidemic unfolds.

  6. Drought and Epidemic Typhus, Central Mexico, 1655–1918

    Science.gov (United States)

    Acuna-Soto, Rudofo; Stahle, David W.

    2014-01-01

    Epidemic typhus is an infectious disease caused by the bacterium Rickettsia prowazekii and transmitted by body lice (Pediculus humanus corporis). This disease occurs where conditions are crowded and unsanitary. This disease accompanied war, famine, and poverty for centuries. Historical and proxy climate data indicate that drought was a major factor in the development of typhus epidemics in Mexico during 1655–1918. Evidence was found for 22 large typhus epidemics in central Mexico, and tree-ring chronologies were used to reconstruct moisture levels over central Mexico for the past 500 years. Below-average tree growth, reconstructed drought, and low crop yields occurred during 19 of these 22 typhus epidemics. Historical documents describe how drought created large numbers of environmental refugees that fled the famine-stricken countryside for food relief in towns. These refugees often ended up in improvised shelters in which crowding encouraged conditions necessary for spread of typhus. PMID:24564928

  7. 北京市门头沟区2007~2009年儿童传染病疫情分析%Analysis of epidemic situation of children infectious diseases in Mentougou district of Beijing from 2007 to 2009

    Institute of Scientific and Technical Information of China (English)

    李龙建; 刘英; 曹殿起; 和丽

    2012-01-01

    目的 分析2007 -2009年北京市门头沟区中小学生和幼托儿童传染病疫情,为传染病的预防控制提供科学依据.方法 采用描述流行病学方法,对中小学生和幼托儿童传染病发病资料进行统计分析.结果 该区中小学生和幼托儿童传染病发病分别为827例和501例;发病数居前5位病种依次为手足口病、其他感染性腹泻病、菌痢、甲型H1N1流感 和猩红热;发病月份主要集中在5月、9月和10月.结论 中小学校应以呼吸道传染病和消化道传染病、幼托机构以经接触传播传染病为防控重点;加强传染病的规范管理和监督检查,做好疫苗的免疫预防接种工作,提高公众对传染病的认知程度.%OBJECTIVE To study the epidemic situation of primary, secondary school students and kindergarten children in Mentougou district of Beijing from 2007 to 2009, and to provide scientific evidences for the control and prevention of infectious diseases. METHODS Descriptive epidemiology was used to analyze the data on the epidemic situation of infectious diseases a-mong primary, secondary school students and kindergarten children in Mentougou district. RESULTS The total cases of infectious diseases was 827 in primary and secondary schools and 501 in kindergartens. The top five diseases of the reported number were as following: hand foot and mouth disease, infectious diarrhea, bacillary dysentery, influenza A H1N1, and scarlet fever. Higher prevalences were concentrated on May, September and October. CONCLUSION More attention should be paid to prevent and control of the respiratory and digestive tract of infectious diseases in primary, secondary schools and the contact transmission of infectious diseases in kindergartens. Strengthen normative administration and supervision and inspection of infectious diseases, and do inoculation work of bacterin well about vaccination, and improve cognizant level of the public about infectious diseases.

  8. Comparing hypothetical versus non-hypothetical methods for measuring willingness to pay in a food context

    Directory of Open Access Journals (Sweden)

    Laura Martínez-Carrasco

    2015-12-01

    Full Text Available Choosing a valid procedure to measure willingness to pay (WTP is crucial for designating optimum price policies or for evaluating the demand for new products. This study compares two methods for obtaining WTP in a food context: a random nth price auction and an open-ended contingent valuation (CV question. Participants were regular salad tomato buyers of Alicante and they were randomly assigned to one of the two treatments. The products about which they would show their WTP were traditional tomato varieties. Both treatments were divided into three stages: in the first stage the only available information was a reference price for the tomatoes. In stages 2 and 3 we revealed the local origin and the organic grown of the tomatoes respectively. Our results show that in the auction the percentage of participants willing to pay the same or more than the reference price was between 20 and 30%. In the CV method this percentage was between 40 and 65%. The mean WTP in the auction, considering the whole of the individuals, was situated between 1.90 and 2.13 €/kg. These same results obtained through the CV were situated between 2.54 and 3.21 €/kg. The results confirmed the findings of previous papers in which the hypothetical bias of CV was clarified because it yields higher values for WTP than the auction, especially when referring to the number of individuals willing to pay more. Additionally, hedonic price models were estimated for the prices obtained by both methods with the result that in all the models, WTP was directly related to the price paid for the latest purchase of tomatoes.

  9. Comparing hypothetical versus non-hypothetical methods for measuring willingness to pay in a food context

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Carrasco, L.; Brugarolas, M.; Martínez-Poveda, A.; Ruiz-Martínez, J.J.

    2015-07-01

    Choosing a valid procedure to measure willingness to pay (WTP) is crucial for designating optimum price policies or for evaluating the demand for new products. This study compares two methods for obtaining WTP in a food context: a random nth price auction and an open-ended contingent valuation (CV) question. Participants were regular salad tomato buyers of Alicante and they were randomly assigned to one of the two treatments. The products about which they would show their WTP were traditional tomato varieties. Both treatments were divided into three stages: in the first stage the only available information was a reference price for the tomatoes. In stages 2 and 3 we revealed the local origin and the organic grown of the tomatoes respectively. Our results show that in the auction the percentage of participants willing to pay the same or more than the reference price was between 20 and 30%. In the CV method this percentage was between 40 and 65%. The mean WTP in the auction, considering the whole of the individuals, was situated between 1.90 and 2.13 €/kg. These same results obtained through the CV were situated between 2.54 and 3.21 €/kg. The results confirmed the findings of previous papers in which the hypothetical bias of CV was clarified because it yields higher values for WTP than the auction, especially when referring to the number of individuals willing to pay more. Additionally, hedonic price models were estimated for the prices obtained by both methods with the result that in all the models, WTP was directly related to the price paid for the latest purchase of tomatoes. (Author)

  10. Analysis of the compatibility of prescriptions depending on nature and flavor of drug in Detailed Analysis of Epidemic Warm Diseases%《温病条辨》咸寒苦甘法应用浅析

    Institute of Scientific and Technical Information of China (English)

    周晓平; 杨进

    2012-01-01

    咸寒苦甘法源于《黄帝内经》.在明清温病学家著述中,记载甚多.《温病条辨》中应用咸寒苦甘法之用在于清心络以开窍闭;清血络以散瘀热;泻结热以存阴液;清阴络以透余邪;补肝肾以救真阴.其病机关键在于邪伏较深,且阴液耗伤明显.分析可见咸寒苦甘法所主病证大多有伤及真阴之险,应以咸寒苦甘法固护真阴为重心,苦寒之品用以泄热存阴,甘寒甘苦法的应用主在留津气.%The compatibility of prescriptions depending onnature and flavor of drug derived from Huangdi Neijing.ln masters of Epidemic Febrile Disease's works, there are many records of that.In Detailed Analysis of Epidemic Warm Diseases, the compatibility aboutcold nature and the tastes: salty, sweet, bitter have the function of dispelling blood stasis andheat, assisting resuscitation, promoting the flow of Qi and blood inmeridians, purgation and saving the body fluid, clearing away heatin Yin collaterals and expelling pathogenic factors, filling liver and kidney and nourishing really Yin. In pathological mechanism we must catch key factors: deep evil and Yin fluid consumption injury obviously. Most diseases due to salty, cold, bitter and sweet may hurt kidney-Yin. So in treatment, salty-cold method should be used to protect kidney-Yin, bitter and cold are used to release heat and keep Yin, and the use of sweet-cold-sweet-bitter method is to storefunctional activities of the body fluid.

  11. A Review of Impact of Bam Earthquake on Cutaneous Leishmaniasis and Status: Epidemic of Old Foci, Emergence of New Foci and Changes in Features of the Disease

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Aflatoonian

    2016-01-01

    Full Text Available Background: Global findings indicate that incidence rate of cutaneous leishmaniasis (CL has significantly in­creased during the past decade, as documented in many countries. This review was aimed to evaluate the trend of CL cases in terms of demographic and clinical characteristics during a decade after the earthquake (2003–2012 com­pared to the corresponding period before the earthquake in Bam (1993–2003.Methods: Direct smear preparations along with different intrinsic methods were used for detection and identification of the causative agents.Results: Overall, 20999 cases of CL have occurred during the last 20 years (1993–2012, 6731 cases before and 14268 cases after the earthquake (P< 0.001.Conclusions: Following a major earthquake, several risk factors could activate epidemics of cutaneous leishmaniasis in old foci and induce emerging foci in new areas.

  12. Lexical exponents of hypothetical modality in Polish and Lithuanian

    Directory of Open Access Journals (Sweden)

    Roman Roszko

    2015-11-01

    To analyse both the languages there is used the method of theoretical contrastive studies, which the most important features are: (1 orienting the studies from the content grounds to the formal grounds, (2 using a semantic interlanguage as tertium comparationis. First of all, the content of hypothetical modality and its definition and paraphrase is given here. Next, the gradational character of this category is discussed. There are distinguished six groups of lexemes expressing the corresponding degrees of hypothetical modality — from a shadow of uncertainty (minimal degree of probability to an almost complete certainty (maximum degree of probability. The experimental Polish-Lithuanian corpus is widely applied in the studies.

  13. The Opioid Epidemic: Crisis and Solutions.

    Science.gov (United States)

    Skolnick, Phil

    2017-10-02

    The widespread abuse of prescription opioids and a dramatic increase in the availability of illicit opioids have created what is commonly referred to as the opioid epidemic. The magnitude of this epidemic is startling: About 4% of the adult US population misuses prescription opioids, and in 2015, more than 33,000 deaths were attributable to overdose with licit and illicit opioids. Increasing the availability of medication-assisted treatments (such as buprenorphine and naltrexone), the use of abuse-deterrent formulations, and the adoption of US Centers for Disease Control and Prevention prescribing guidelines all constitute short-term approaches to quell this epidemic. However, with more than 125 million Americans suffering from either acute or chronic pain, the development of effective alternatives to opioids, enabled at least in part by a fuller understanding of the neurobiological bases of pain, offers the best long-term solution for controlling and ultimately eradicating this epidemic. Expected final online publication date for the Annual Review of Pharmacology and Toxicology Volume 58 is January 6, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  14. Computational algebraic geometry of epidemic models

    Science.gov (United States)

    Rodríguez Vega, Martín.

    2014-06-01

    Computational Algebraic Geometry is applied to the analysis of various epidemic models for Schistosomiasis and Dengue, both, for the case without control measures and for the case where control measures are applied. The models were analyzed using the mathematical software Maple. Explicitly the analysis is performed using Groebner basis, Hilbert dimension and Hilbert polynomials. These computational tools are included automatically in Maple. Each of these models is represented by a system of ordinary differential equations, and for each model the basic reproductive number (R0) is calculated. The effects of the control measures are observed by the changes in the algebraic structure of R0, the changes in Groebner basis, the changes in Hilbert dimension, and the changes in Hilbert polynomials. It is hoped that the results obtained in this paper become of importance for designing control measures against the epidemic diseases described. For future researches it is proposed the use of algebraic epidemiology to analyze models for airborne and waterborne diseases.

  15. Restraining Epidemics by Improving Immunization Strategies

    CERN Document Server

    Schneider, Christian M; Havlin, Shlomo; Herrmann, Hans J

    2011-01-01

    The way diseases spread through social and global transportation networks is crucially determining their risk for humanity. Based on percolation theory we quantitatively analyze the effect of immunization strategies on the spreading of diseases through networks and propose a novel approach to improve their effectiveness. We find that the network's vulnerability to epidemics can be significantly reduced by implementing improved immunization strategies based on high betweenness centrality. We demonstrate this on two real networks, the global flight network, which is known as the most important source of pandemic spreading and a school friendship network. In theses networks, the average probability for a node to get infected is reduced by more than 10% compared to the betweenness centrality method believed to be the most efficient strategy to prevent epidemic spreading.

  16. Epidemic spreading with immunization rate on complex networks

    CERN Document Server

    Tanimoto, Shinji

    2011-01-01

    We investigate the spread of diseases, computer viruses or information on complex networks and also immunization strategies to prevent or control the spread. When an entire population cannot be immunized and the effect of immunization is not perfect, we need the targeted immunization with immunization rate. Under such a circumstance we calculate epidemic thresholds for the SIR and SIS epidemic models. It is shown that, in scale-free networks, the targeted immunization is effective only if the immunization rate is equal to one. We analyze here epidemic spreading on directed complex networks, but similar results are also valid for undirected ones.

  17. Mathematical models to characterize early epidemic growth: A review

    Science.gov (United States)

    Chowell, Gerardo; Sattenspiel, Lisa; Bansal, Shweta; Viboud, Cécile

    2016-09-01

    There is a long tradition of using mathematical models to generate insights into the transmission dynamics of infectious diseases and assess the potential impact of different intervention strategies. The increasing use of mathematical models for epidemic forecasting has highlighted the importance of designing reliable models that capture the baseline transmission characteristics of specific pathogens and social contexts. More refined models are needed however, in particular to account for variation in the early growth dynamics of real epidemics and to gain a better understanding of the mechanisms at play. Here, we review recent progress on modeling and characterizing early epidemic growth patterns from infectious disease outbreak data, and survey the types of mathematical formulations that are most useful for capturing a diversity of early epidemic growth profiles, ranging from sub-exponential to exponential growth dynamics. Specifically, we review mathematical models that incorporate spatial details or realistic population mixing structures, including meta-population models, individual-based network models, and simple SIR-type models that incorporate the effects of reactive behavior changes or inhomogeneous mixing. In this process, we also analyze simulation data stemming from detailed large-scale agent-based models previously designed and calibrated to study how realistic social networks and disease transmission characteristics shape early epidemic growth patterns, general transmission dynamics, and control of international disease emergencies such as the 2009 A/H1N1 influenza pandemic and the 2014-2015 Ebola epidemic in West Africa.

  18. Memory effects on epidemic evolution: The susceptible-infected-recovered epidemic model

    Science.gov (United States)

    Saeedian, M.; Khalighi, M.; Azimi-Tafreshi, N.; Jafari, G. R.; Ausloos, M.

    2017-02-01

    Memory has a great impact on the evolution of every process related to human societies. Among them, the evolution of an epidemic is directly related to the individuals' experiences. Indeed, any real epidemic process is clearly sustained by a non-Markovian dynamics: memory effects play an essential role in the spreading of diseases. Including memory effects in the susceptible-infected-recovered (SIR) epidemic model seems very appropriate for such an investigation. Thus, the memory prone SIR model dynamics is investigated using fractional derivatives. The decay of long-range memory, taken as a power-law function, is directly controlled by the order of the fractional derivatives in the corresponding nonlinear fractional differential evolution equations. Here we assume "fully mixed" approximation and show that the epidemic threshold is shifted to higher values than those for the memoryless system, depending on this memory "length" decay exponent. We also consider the SIR model on structured networks and study the effect of topology on threshold points in a non-Markovian dynamics. Furthermore, the lack of access to the precise information about the initial conditions or the past events plays a very relevant role in the correct estimation or prediction of the epidemic evolution. Such a "constraint" is analyzed and discussed.

  19. Phylogeography and molecular epidemiology of an epidemic strain of dengue virus type 1 in Sri Lanka.

    Science.gov (United States)

    Ocwieja, Karen E; Fernando, Anira N; Sherrill-Mix, Scott; Sundararaman, Sesh A; Tennekoon, Rashika N; Tippalagama, Rashmi; Krishnananthasivam, Shivankari; Premawansa, Gayani; Premawansa, Sunil; De Silva, Aruna Dharshan

    2014-08-01

    In 2009, a severe epidemic of dengue disease occurred in Sri Lanka, with higher mortality and morbidity than any previously recorded epidemic in the country. It corresponded to a shift to dengue virus 1 as the major disease-causing serotype in Sri Lanka. Dengue disease reached epidemic levels in the next 3 years. We report phylogenetic evidence that the 2009 epidemic DENV-1 strain continued to circulate within the population and caused severe disease in the epidemic of 2012. Bayesian phylogeographic analyses suggest that the 2009 Sri Lankan epidemic DENV-1 strain may have traveled directly or indirectly from Thailand through China to Sri Lanka, and after spreading within the Sri Lankan population, it traveled to Pakistan and Singapore. Our findings delineate the dissemination route of a virulent DENV-1 strain in Asia. Understanding such routes will be of particular importance to global control efforts.

  20. Large epidemic thresholds emerge in heterogeneous networks of heterogeneous nodes

    CERN Document Server

    Yang, Hui; Gross, Thilo

    2015-01-01

    One of the famous results of network science states that networks with heterogeneous connectivity are more susceptible to epidemic spreading than their more homogeneous counterparts. In particular, in networks of identical nodes it has been shown that heterogeneity can lower the epidemic threshold at which epidemics can invade the system. Network heterogeneity can thus allow diseases with lower transmission probabilities to persist and spread. Here, we point out that for real world applications, this result should not be regarded independently of the intra-individual heterogeneity between people. Our results show that, if heterogeneity among people is taken into account, networks that are more heterogeneous in connectivity can be more resistant to epidemic spreading. We study a susceptible-infected-susceptible model with adaptive disease avoidance. Results from this model suggest that this reversal of the effect of network heterogeneity is likely to occur in populations in which the individuals are aware of t...

  1. [Hippocrates. Aphorisms and Epidemics III. Two clinical texts].

    Science.gov (United States)

    Frøland, Anders

    2015-01-01

    The two Hippocratic texts, Aphorisms and Epidemics III, have not been translated into Danish previously. The Aphorisms are 412 short, pithy statements, mostly on the prognosis in relation to certain symptoms in the course of the diseases, very often febrile. The Aphorisms begin with the famous words: "Life is short, the Art long, opportunity fleeting, experiment treacherous, judgment difficult." (Transl. W H S Jones [22]). Epidemics III consists of 28 case histories, again mostly of febrile patients, but also of observations on the connection of the seasons with general morbidity and mortality. The author describes an epidemic, which in some respects resembles Thucydides' report on the plague in Athens in 430 BC. It is suggested, that observations as have been recorded in the seven Hippocratic texts on epidemic diseases are the material on which prognostic statements as those collected in the Aphorisms are founded.

  2. Topology dependent epidemic spreading velocity in weighted networks

    Science.gov (United States)

    Duan, Wei; Quax, Rick; Lees, Michael; Qiu, Xiaogang; Sloot, Peter M. A.

    2014-12-01

    Many diffusive processes occur on structured networks with weighted links, such as disease spread by airplane transport or information diffusion in social networks or blogs. Understanding the impact of weight-connectivity correlations on epidemic spreading in weighted networks is crucial to support decision-making on disease control and other diffusive processes. However, a real understanding of epidemic spreading velocity in weighted networks is still lacking. Here we conduct a numerical study of the velocity of a Reed-Frost epidemic spreading process in various weighted network topologies as a function of the correlations between edge weights and node degrees. We find that a positive weight-connectivity correlation leads to a faster epidemic spreading compared to an unweighted network. In contrast, we find that both uncorrelated and negatively correlated weight distributions lead to slower spreading processes. In the case of positive weight-connectivity correlations, the acceleration of spreading velocity is weak when the heterogeneity of weight distribution increases.

  3. 明清温病学家对阴阳学说的阐释与应用%Interpretation and application of theory of yin and yang by physicians of Epidemic Febrile Diseases in Ming and Qing dynasty

    Institute of Scientific and Technical Information of China (English)

    肖连宇; 赵岩松

    2016-01-01

    阴阳学说是中医学理论体系的基础。明清时期温病学派兴起,多用寒凉,重视养阴,改变了援易说医、贵阳贱阴的风气,而阴阳学说的基本特征仍体现在温病学派诸家的辨治特色中。以叶天士为代表的温病学家进一步发展了阴阳学说,并将阴阳平衡观体现在其“存津液”“养阴血”“通阳气”等辨治特色中。%Theory of yin and yang is the foundation of TCMtheoretical system.In Ming and Qing dynasty, school of Epidemic Febrile Diseases was rising,with the characteristics of drugs with cold or cool property in prescriptions and methods of nourishing yin.Although the arising school changed the conventional situ-ations of “using Changes to explain TCM”and “recuperating yang should be always considered as impor-tant rather than replenishing yin”,the basic feature of theory of yin and yang undoubtedly lay in its spe-cific differentiation and treatment.The physicians of Epidemic Febrile Diseases,with the representation of YE Tianshi,developed the theory of yin and yang of “preserving the body fluids”,“nourishing Yin and blood”and “promoting the flow of yang and qi”.

  4. Epidemic model with isolation in multilayer networks

    CERN Document Server

    Zuzek, L G Alvarez; Braunstein, L A

    2014-01-01

    The Susceptible-Infected-Recovered (SIR) model has successfully mimicked the propagation of such airborne diseases as influenza A (H1N1). Although the SIR model has recently been studied in a multilayer networks configuration, in almost all the research the dynamic movement of infected individuals, e.g., how they are often kept in isolation, is disregarded. We study the SIR model in two multilayer networks and use an isolation parameter, indicating time period, to measure the effect of isolating infected individuals from both layers. This isolation reduces the transmission of the disease because the time in which infection can spread is reduced. In this scenario we find that the epidemic threshold increases with the isolation time and the isolation parameter and the impact of the propagation is reduced. We also find that when isolation is total there is a threshold for the isolation parameter above which the disease never becomes an epidemic. We also find that regular epidemic models always overestimate the e...

  5. Epidemic spreading in random rectangular networks

    Science.gov (United States)

    Estrada, Ernesto; Meloni, Sandro; Sheerin, Matthew; Moreno, Yamir

    2016-11-01

    The use of network theory to model disease propagation on populations introduces important elements of reality to the classical epidemiological models. The use of random geometric graphs (RGGs) is one of such network models that allows for the consideration of spatial properties on disease propagation. In certain real-world scenarios—like in the analysis of a disease propagating through plants—the shape of the plots and fields where the host of the disease is located may play a fundamental role in the propagation dynamics. Here we consider a generalization of the RGG to account for the variation of the shape of the plots or fields where the hosts of a disease are allocated. We consider a disease propagation taking place on the nodes of a random rectangular graph and we consider a lower bound for the epidemic threshold of a susceptible-infected-susceptible model or a susceptible-infected-recovered model on these networks. Using extensive numerical simulations and based on our analytical results we conclude that (ceteris paribus) the elongation of the plot or field in which the nodes are distributed makes the network more resilient to the propagation of a disease due to the fact that the epidemic threshold increases with the elongation of the rectangle. These results agree with accumulated empirical evidence and simulation results about the propagation of diseases on plants in plots or fields of the same area and different shapes.

  6. Preferences for Physically Disabled Counselors in Hypothetical Counseling Situations

    Science.gov (United States)

    Mitchell, David C.; Frederickson, William A.

    1975-01-01

    The preferences of 320 undergraduate students for one of three disabled counselors or for a nondisabled counselor on each of Brabham and Thoreson's 20 hypothetical counseling situations were obtained. Significant counselor preferences existed for 18 of the 20 situations, and when categorized by sex, significant counselor preferences existed for 4…

  7. Genome-wide screens for expressed hypothetical proteins

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Durhuus, Jon Ambæk; Rasmussen, Lene Juel

    2012-01-01

    A hypothetical protein (HP) is defined as a protein that is predicted to be expressed from an open reading frame, but for which there is no experimental evidence of translation. HPs constitute a substantial fraction of proteomes of human as well as of other organisms. With the general belief...

  8. The Chandrasekhar's Equation for Two-Dimensional Hypothetical White Dwarfs

    CERN Document Server

    De, Sanchari

    2014-01-01

    In this article we have extended the original work of Chandrasekhar on the structure of white dwarfs to the two-dimensional case. Although such two-dimensional stellar objects are hypothetical in nature, we strongly believe that the work presented in this article may be prescribed as Master of Science level class problem for the students in physics.

  9. Scaffolding for Argumentation in Hypothetical and Theoretical Biology Concepts

    Science.gov (United States)

    Weng, Wan-Yun; Lin, Yu-Ren; She, Hsiao-Ching

    2017-01-01

    The present study investigated the effects of online argumentation scaffolding on students' argumentation involving hypothetical and theoretical biological concepts. Two types of scaffolding were developed in order to improve student argumentation: continuous scaffolding and withdraw scaffolding. A quasi-experimental design was used with four…

  10. Hypothetical Markets: Educational Application of Ronald Dworkin's "Sovereign Virtue"

    Science.gov (United States)

    Gough, Stephen

    2006-01-01

    The purpose of this paper is to consider, in principle and at the most general level, a particular possible approach to educational policy-making. This approach involves an education-specific application of the notion of hypothetical markets first developed in Ronald Dworkin's book "Sovereign Virtue: The theory and practice of equality" (2000).…

  11. A Hypothetical Learning Trajectory for Conceptualizing Matrices as Linear Transformations

    Science.gov (United States)

    Andrews-Larson, Christine; Wawro, Megan; Zandieh, Michelle

    2017-01-01

    In this paper, we present a hypothetical learning trajectory (HLT) aimed at supporting students in developing flexible ways of reasoning about matrices as linear transformations in the context of introductory linear algebra. In our HLT, we highlight the integral role of the instructor in this development. Our HLT is based on the "Italicizing…

  12. Substance Abuse Counselors and Moral Reasoning: Hypothetical and Authentic Dilemmas

    Science.gov (United States)

    Sias, Shari M.

    2009-01-01

    This exploratory study examined the assumption that the level of moral reasoning (Defining Issues Test; J. R. Rest, 1986) used in solving hypothetical and authentic dilemmas is similar for substance abuse counselors (N = 188). The statistical analyses used were paired-sample t tests, Pearson product-moment correlation, and simultaneous multiple…

  13. Model of epidemic control based on quarantine and message delivery

    Science.gov (United States)

    Wang, Xingyuan; Zhao, Tianfang; Qin, Xiaomeng

    2016-09-01

    The model provides two novel strategies for the preventive control of epidemic diseases. One approach is related to the different isolating rates in latent period and invasion period. Experiments show that the increasing of isolating rates in invasion period, as long as over 0.5, contributes little to the preventing of epidemic; the improvement of isolation rate in latent period is key to control the disease spreading. Another is a specific mechanism of message delivering and forwarding. Information quality and information accumulating process are also considered there. Macroscopically, diseases are easy to control as long as the immune messages reach a certain quality. Individually, the accumulating messages bring people with certain immunity to the disease. Also, the model is performed on the classic complex networks like scale-free network and small-world network, and location-based social networks. Results show that the proposed measures demonstrate superior performance and significantly reduce the negative impact of epidemic disease.

  14. Absence of epidemic thresholds in a growing adaptive network

    CERN Document Server

    Demirel, Güven

    2012-01-01

    The structure of social contact networks strongly influences the dynamics of epidemic diseases. In particular the scale-free structure of real-world social networks allows unlikely diseases with low infection rates to spread and become endemic. However, in particular for potentially fatal diseases, also the impact of the disease on the social structure cannot be neglected, leading to a complex interplay. Here, we consider the growth of a network by preferential attachment from which nodes are simultaneously removed due to an SIR epidemic. We show that increased infectiousness increases the prevalence of the disease and simultaneously causes a transition from scale-free to exponential topology. Although a transition to a degree distribution with finite variance takes place, the network still exhibits no epidemic threshold in the thermodynamic limit. We illustrate these results using agent-based simulations and analytically tractable approximation schemes.

  15. Survey of three bacterial louse-associated diseases among rural Andean communities in Peru: prevalence of epidemic typhus, trench fever, and relapsing fever.

    Science.gov (United States)

    Raoult, D; Birtles, R J; Montoya, M; Perez, E; Tissot-Dupont, H; Roux, V; Guerra, H

    1999-08-01

    Typhus and other louse-transmitted bacterial infections in Peruvian sierra communities are known to occur but have not recently been assessed. In this study, 194 of 1,280 inhabitants of four villages in Calca Province in the Urubamba Valley were included. Thirty-nine (20%) of the 194 volunteers had antibodies to Rickettsia prowazekii, whereas 24 (12%) had antibodies to Bartonella quintana and 2 against Borrelia recurrentis. There was a significant correlation between the presence of infesting ectoparasites and antibodies to R. prowazekii, as well as between antibodies to R. prowazekii and ectoparasite infestation and fever in the previous 6 months. The proportion of inhabitants infested with ectoparasites was significantly higher in the highest-altitude village than in the other three villages. Two volunteers' antibody levels suggested a recent typhus infection, but only B. quintana DNA was amplified from lice. Epidemic typhus remains extant in the area, and B. quintana infections were encountered and documented for the first time in South America.

  16. Development of the full-length cDNA clones of two porcine epidemic diarrhea disease virus isolates with different virulence

    Science.gov (United States)

    Li, Jie; Jin, Zhonghui; Gao, Yueyi; Zhou, Lei; Ge, Xinna; Guo, Xin; Yang, Hanchun

    2017-01-01

    The recently emerged highly virulent variants of porcine epidemic and diarrhea virus (PEDV) remain a huge threat to the worldwide swine industry. Here, we describe the development of a bacterial artificial chromosome (BAC) reverse genetics system for PEDV based on two recent Chinese field isolates, namely CHM2013 and BJ2011C. Phylogenetically, CHM2013 is closely related to the vaccine strain SM98 whereas the isolate BJ2011C belongs to the GIIb group, a cluster that contains many recent pandemic strains. The full-length cDNA clones of the two isolates were constructed into BAC under the control of CMV promoter. The rescued viruses rBJ2011C and rCHM2013 were found to replicate at the kinetics similar to their respective parental viruses in cell culture. When tested in the 2-day-old pig model, rBJ2011C caused severe diarrhea of piglets with extensive damages to the intestinal epithelium, leading to 100% fatality within 48 hours. In contrast, the rCHM2013-inoculated piglets all survived with only very minor tissue damage observed. Thus, we have successfully established a convenient platform for PEDV genome manipulation. This study also represents the first description of a DNA-launched reverse genetics system for the highly virulent PEDV. PMID:28301551

  17. Structural Analysis of Hypothetical Proteins from Helicobacter pylori: An Approach to Estimate Functions of Unknown or Hypothetical Proteins

    Directory of Open Access Journals (Sweden)

    Bong-Jin Lee

    2012-06-01

    Full Text Available Helicobacter pylori (H. pylori have a unique ability to survive in extreme acidic environments and to colonize the gastric mucosa. It can cause diverse gastric diseases such as peptic ulcers, chronic gastritis, mucosa-associated lymphoid tissue (MALT lymphoma, gastric cancer, etc. Based on genomic research of H. pylori, over 1600 genes have been functionally identified so far. However, H. pylori possess some genes that are uncharacterized since: (i the gene sequences are quite new; (ii the function of genes have not been characterized in any other bacterial systems; and (iii sometimes, the protein that is classified into a known protein based on the sequence homology shows some functional ambiguity, which raises questions about the function of the protein produced in H. pylori. Thus, there are still a lot of genes to be biologically or biochemically characterized to understand the whole picture of gene functions in the bacteria. In this regard, knowledge on the 3D structure of a protein, especially unknown or hypothetical protein, is frequently useful to elucidate the structure-function relationship of the uncharacterized gene product. That is, a structural comparison with known proteins provides valuable information to help predict the cellular functions of hypothetical proteins. Here, we show the 3D structures of some hypothetical proteins determined by NMR spectroscopy and X-ray crystallography as a part of the structural genomics of H. pylori. In addition, we show some successful approaches of elucidating the function of unknown proteins based on their structural information.

  18. In Silico Structural and Functional Annotation of Hypothetical Proteins of Vibrio cholerae O139

    Science.gov (United States)

    Islam, Md. Saiful; Shahik, Shah Md.; Sohel, Md.; Patwary, Noman I. A.

    2015-01-01

    In developing countries threat of cholera is a significant health concern whenever water purification and sewage disposal systems are inadequate. Vibrio cholerae is one of the responsible bacteria involved in cholera disease. The complete genome sequence of V. cholerae deciphers the presence of various genes and hypothetical proteins whose function are not yet understood. Hence analyzing and annotating the structure and function of hypothetical proteins is important for understanding the V. cholerae. V. cholerae O139 is the most common and pathogenic bacterial strain among various V. cholerae strains. In this study sequence of six hypothetical proteins of V. cholerae O139 has been annotated from NCBI. Various computational tools and databases have been used to determine domain family, protein-protein interaction, solubility of protein, ligand binding sites etc. The three dimensional structure of two proteins were modeled and their ligand binding sites were identified. We have found domains and families of only one protein. The analysis revealed that these proteins might have antibiotic resistance activity, DNA breaking-rejoining activity, integrase enzyme activity, restriction endonuclease, etc. Structural prediction of these proteins and detection of binding sites from this study would indicate a potential target aiding docking studies for therapeutic designing against cholera. PMID:26175663

  19. Reconstructing the 2003/2004 H3N2 influenza epidemic in Switzerland with a spatially explicit, individual-based model

    Directory of Open Access Journals (Sweden)

    Zinsstag Jakob

    2011-05-01

    Full Text Available Abstract Background Simulation models of influenza spread play an important role for pandemic preparedness. However, as the world has not faced a severe pandemic for decades, except the rather mild H1N1 one in 2009, pandemic influenza models are inherently hypothetical and validation is, thus, difficult. We aim at reconstructing a recent seasonal influenza epidemic that occurred in Switzerland and deem this to be a promising validation strategy for models of influenza spread. Methods We present a spatially explicit, individual-based simulation model of influenza spread. The simulation model bases upon (i simulated human travel data, (ii data on human contact patterns and (iii empirical knowledge on the epidemiology of influenza. For model validation we compare the simulation outcomes with empirical knowledge regarding (i the shape of the epidemic curve, overall infection rate and reproduction number, (ii age-dependent infection rates and time of infection, (iii spatial patterns. Results The simulation model is capable of reproducing the shape of the 2003/2004 H3N2 epidemic curve of Switzerland and generates an overall infection rate (14.9 percent and reproduction numbers (between 1.2 and 1.3, which are realistic for seasonal influenza epidemics. Age and spatial patterns observed in empirical data are also reflected by the model: Highest infection rates are in children between 5 and 14 and the disease spreads along the main transport axes from west to east. Conclusions We show that finding evidence for the validity of simulation models of influenza spread by challenging them with seasonal influenza outbreak data is possible and promising. Simulation models for pandemic spread gain more credibility if they are able to reproduce seasonal influenza outbreaks. For more robust modelling of seasonal influenza, serological data complementing sentinel information would be beneficial.

  20. Epidemia de doença meningocócica, 1970/1977: aparecimento e disseminação do processo epidêmico The epidemics of meningococcal disease, 1970/1977: its appearance and spread

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Barradas Barata

    1988-02-01

    Full Text Available Estuda-se o aparecimento da epidemia de doença meningocócica e sua disseminação na Cidade de São Paulo, SP (Brasil, destacando-se a progressão no tempo (mês de início do processo e no espaço (subdistritos e distritos. A análise dos diagramas de controle construídos a partir da experiência em anos endêmicos (1960/1969, por subdistritos e distritos da Capital, permite evidenciar a progressão da epidemia em ondas concêntricas, da periferia para as áreas centrais, a partir de janeiro de 1970. Os dados empíricos permitem mostrar a distribuição heterogênea dos casos nos diferentes segmentos da população.The beginning of the epidemics of meningococcal disease and its spread within the City of São Paulo is studied with emphasis given to its advance in time (month when it began and space (quarters and districts of the city. The analysis of the control charts that were built up from the data of the endemic years (1960 to 1969 for the quarters and districts of the city, gives evidence that the epidemics spread in concentric waves from the outskirts of the city into the central areas, and began in January, 1970. The empirical data also show that the cases were heterogeneously distributed in the different strata of the population.

  1. Investigation of airborne foot-and-mouth disease virus transmission during low-wind conditions in the early phase of the UK 2001 epidemic

    DEFF Research Database (Denmark)

    Mikkelsen, T.; Alexandersen, S.; Astrup, P.

    2003-01-01

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed domesticated and wild animals. The highly contagious nature of FMD is a reflection of the wide range of host species, the enormous quantities of virus liberated by infected animals, the range of excretions and secr......Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed domesticated and wild animals. The highly contagious nature of FMD is a reflection of the wide range of host species, the enormous quantities of virus liberated by infected animals, the range of excretions...... paper (Gloster et al., 2002) provides a more detailed analysis of the airborne disease transmission in the vicinity of Burnside Farm. The combined results are consistent with airborne transmission of disease to livestock in the Heddon-on-the-Wall area. Local topography may have played a significant role...

  2. An epidemic model for the future progression of the current Haiti cholera epidemic

    Science.gov (United States)

    Bertuzzo, E.; Mari, L.; Righetto, L.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2012-04-01

    As a major cholera epidemic progresses in Haiti, and the figures of the infection, up to December 2011, climb to 522,000 cases and 7,000 deaths, the development of general models to track and predict the evolution of the outbreak, so as to guide the allocation of medical supplies and staff, is gaining notable urgency. We propose here a spatially explicit epidemic model that accounts for the dynamics of susceptible and infected individuals as well as the redistribution of Vibrio cholera, the causative agent of the disease, among different human communities. In particular, we model two spreading pathways: the advection of pathogens through hydrologic connections and the dissemination due to human mobility described by means of a gravity-like model. To this end the country has been divided into hydrologic units based on drainage directions derived from a digital terrain model. Moreover the population of each unit has been estimated from census data downscaled to 1 km x 1 km resolution via remotely sensed geomorphological information (LandScan project). The model directly accounts for the role of rainfall patterns in driving the seasonality of cholera outbreaks. The two main outbreaks in fact occurred during the rainy seasons (October and May) when extensive floodings severely worsened the sanitation conditions and, in turn, raised the risk of infection. The model capability to reproduce the spatiotemporal features of the epidemic up to date grants robustness to the foreseen future development. To this end, we generate realistic scenario of future precipitation in order to forecast possible epidemic paths up to the end of the 2013. In this context, the duration of acquired immunity, a hotly debated topic in the scientific community, emerges as a controlling factor for progression of the epidemic in the near future. The framework presented here can straightforwardly be used to evaluate the effectiveness of alternative intervention strategies like mass vaccinations

  3. Spatiotemporal Evolution of Ebola Virus Disease at Sub-National Level during the 2014 West Africa Epidemic: Model Scrutiny and Data Meagreness.

    Directory of Open Access Journals (Sweden)

    Eva Santermans

    Full Text Available The Ebola outbreak in West Africa has infected at least 27,443 individuals and killed 11,207, based on data until 24 June, 2015, released by the World Health Organization (WHO. This outbreak has been characterised by extensive geographic spread across the affected countries Guinea, Liberia and Sierra Leone, and by localized hotspots within these countries. The rapid recognition and quantitative assessment of localised areas of higher transmission can inform the optimal deployment of public health resources.A variety of mathematical models have been used to estimate the evolution of this epidemic, and some have pointed out the importance of the spatial heterogeneity apparent from incidence maps. However, little is known about the district-level transmission. Given that many response decisions are taken at sub-national level, the current study aimed to investigate the spatial heterogeneity by using a different modelling framework, built on publicly available data at district level. Furthermore, we assessed whether this model could quantify the effect of intervention measures and provide predictions at a local level to guide public health action. We used a two-stage modelling approach: a a flexible spatiotemporal growth model across all affected districts and b a deterministic SEIR compartmental model per district whenever deemed appropriate.Our estimates show substantial differences in the evolution of the outbreak in the various regions of Guinea, Liberia and Sierra Leone, illustrating the importance of monitoring the outbreak at district level. We also provide an estimate of the time-dependent district-specific effective reproduction number, as a quantitative measure to compare transmission between different districts and give input for informed decisions on control measures and resource allocation. Prediction and assessing the impact of control measures proved to be difficult without more accurate data. In conclusion, this study provides us a

  4. [The depression epidemic does not exist].

    Science.gov (United States)

    van der Feltz-Cornelis, Christina M

    2009-01-01

    There has been much discussion in the media about the question of the existence of a depression epidemic. This leads on to the questions of whether the social and economic approaches are adequate, and what the alternatives are. The concept of the disease 'depression' can be defined using a medical model, or from a patient's or a societal perspective. From a medical perspective, indeed a depression epidemic has ensued from the increased prosperity and the associated decompression of the mortality rate. Society responded with preventative measures and policies aimed at improving functioning in the workplace. However, patients with a major depressive disorder (MDD) who are eligible for treatment are often not motivated to take it up, or are undertreated. Research is necessary in order to explore what patients think about the identification and treatment of depression. The confusion regarding the concept of depression found in the media, needs to be cleared.

  5. Epidemic spreading on dual-structure networks with mobile agents

    Science.gov (United States)

    Yao, Yiyang; Zhou, Yinzuo

    2017-02-01

    The rapid development of modern society continually transforms the social structure which leads to an increasingly distinct dual structure of higher population density in urban areas and lower density in rural areas. Such structure may induce distinctive spreading behavior of epidemics which does not happen in a single type structure. In this paper, we study the epidemic spreading of mobile agents on dual structure networks based on SIRS model. First, beyond the well known epidemic threshold for generic epidemic model that when the infection rate is below the threshold a pertinent infectious disease will die out, we find the other epidemic threshold which appears when the infection rate of a disease is relatively high. This feature of two thresholds for the SIRS model may lead to the elimination of infectious disease when social network has either high population density or low population density. Interestingly, however, we find that when a high density area is connected to a low density may cause persistent spreading of the infectious disease, even though the same disease will die out when it spreads in each single area. This phenomenon indicates the critical role of the connection between the two areas which could radically change the behavior of spreading dynamics. Our findings, therefore, provide new understanding of epidemiology pertinent to the characteristic modern social structure and have potential to develop controlling strategies accordingly.

  6. Surveillance and control of meningococcal meningitis epidemics in refugee populations.

    Science.gov (United States)

    Moore, P S; Toole, M J; Nieburg, P; Waldman, R J; Broome, C V

    1990-01-01

    Epidemics of communicable diseases pose a direct threat to refugee and internally displaced populations, and could lead to high mortality rates and a disruption of basic health care services. Several large refugee populations live in regions of high meningococcal disease endemicity and their camps are at risk for outbreaks of meningococcal meningitis. Surveillance in these camps allows early detection and control of impending outbreaks. Confirmation of meningococcal disease can be performed under field conditions using simple techniques, such as latex agglutination. Isolates should be obtained for serogroup confirmation and antibiotic sensitivity studies at reference laboratories. Serogroup information is used to determine the risk of widespread epidemic disease and the utility of available vaccines. During epidemics, treatment regimens should be standardized, preferably with an effective single-dose antibiotic. Mass vaccination campaigns should be initiated, the populations at high risk being targeted for vaccination as quickly as possible. When the risk of epidemic disease is deemed to be high, preemptive vaccination may be warranted. Daily surveillance using a simple case definition is essential during an epidemic to determine the effectiveness of control measures and to delineate high-risk groups for vaccination or chemoprophylaxis. Many of these recommendations can be applied also to other populations in developing countries.

  7. Epidemic spreading in time-varying community networks

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Guangming, E-mail: wangxy@dlut.edu.cn, E-mail: ren-guang-ming@163.com [School of Electronic and Information, Guangdong Polytechnic Normal University, Guangzhou 510665 (China); Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Xingyuan, E-mail: wangxy@dlut.edu.cn, E-mail: ren-guang-ming@163.com [Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2014-06-15

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold q{sub c}. The epidemic will survive when q > q{sub c} and die when q < q{sub c}. These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure.

  8. Modeling and Analysis of Epidemic Diffusion with Population Migration

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2013-01-01

    Full Text Available An improved Susceptible-Infected-Susceptible (SIS epidemic diffusion model with population migration between two cities is modeled. Global stability conditions for both the disease-free equilibrium and the endemic equilibrium are analyzed and proved. The main contribution of this paper is reflected in epidemic modeling and analysis which considers unequal migration rates, and only susceptible individuals can migrate between the two cities. Numerical simulation shows when the epidemic diffusion system is stable, number of infected individuals in one city can reach zero, while the number of infected individuals in the other city is still positive. On the other hand, decreasing population migration in only one city seems not as effective as improving the recovery rate for controlling the epidemic diffusion.

  9. A simple model for behaviour change in epidemics

    Directory of Open Access Journals (Sweden)

    Brauer Fred

    2011-02-01

    Full Text Available Abstract Background People change their behaviour during an epidemic. Infectious members of a population may reduce the number of contacts they make with other people because of the physical effects of their illness and possibly because of public health announcements asking them to do so in order to decrease the number of new infections, while susceptible members of the population may reduce the number of contacts they make in order to try to avoid becoming infected. Methods We consider a simple epidemic model in which susceptible and infectious members respond to a disease outbreak by reducing contacts by different fractions and analyze the effect of such contact reductions on the size of the epidemic. We assume constant fractional reductions, without attempting to consider the way in which susceptible members might respond to information about the epidemic. Results We are able to derive upper and lower bounds for the final size of an epidemic, both for simple and staged progression models. Conclusions The responses of uninfected and infected individuals in a disease outbreak are different, and this difference affects estimates of epidemic size.

  10. ERPs reveal sensitivity to hypothetical contexts in spoken discourse.

    Science.gov (United States)

    Dwivedi, Veena D; Drury, John E; Molnar, Monika; Phillips, Natalie A; Baum, Shari; Steinhauer, Karsten

    2010-08-04

    We used event-related potentials to examine the interaction between two dimensions of discourse comprehension: (i) referential dependencies across sentences (e.g. between the pronoun 'it' and its antecedent 'a novel' in: 'John is reading a novel. It ends quite abruptly'), and (ii) the distinction between reference to events/situations and entities/individuals in the real/actual world versus in hypothetical possible worlds. Cross-sentential referential dependencies are disrupted when the antecedent for a pronoun is embedded in a sentence introducing hypothetical entities (e.g. 'John is considering writing a novel. It ends quite abruptly'). An earlier event-related potential reading study showed such disruptions yielded a P600-like frontal positivity. Here we replicate this effect using auditorily presented sentences and discuss the implications for our understanding of discourse-level language processing.

  11. ATOME : a blackboard architecture with temporal and hypothetical reasoning

    OpenAIRE

    Laasri, Hassan; Maitre, Brigitte; Mondot, Thierry; Charpillet, François; Haton, Jean-Paul

    1988-01-01

    To cope with high level AI-based applications as signal understanding, process control or decision making, an AI system must take into account various knowledge sources and reasoning schemes. In this paper, we propose a blackboard-based architecture which achieves opportunism and efficiency while controlling multiple knowledge sources. In addition it integrates temporal and hypothetical reasoning to deal with applications evolving in time, and manipulating noisy or errorfull information.

  12. Processing counterfactual and hypothetical conditionals: an fMRI investigation.

    Science.gov (United States)

    Kulakova, Eugenia; Aichhorn, Markus; Schurz, Matthias; Kronbichler, Martin; Perner, Josef

    2013-05-15

    Counterfactual thinking is ubiquitous in everyday life and an important aspect of cognition and emotion. Although counterfactual thought has been argued to differ from processing factual or hypothetical information, imaging data which elucidate these differences on a neural level are still scarce. We investigated the neural correlates of processing counterfactual sentences under visual and aural presentation. We compared conditionals in subjunctive mood which explicitly contradicted previously presented facts (i.e. counterfactuals) to conditionals framed in indicative mood which did not contradict factual world knowledge and thus conveyed a hypothetical supposition. Our results show activation in right occipital cortex (cuneus) and right basal ganglia (caudate nucleus) during counterfactual sentence processing. Importantly the occipital activation is not only present under visual presentation but also with purely auditory stimulus presentation, precluding a visual processing artifact. Thus our results can be interpreted as reflecting the fact that counterfactual conditionals pragmatically imply the relevance of keeping in mind both factual and supposed information whereas the hypothetical conditionals imply that real world information is irrelevant for processing the conditional and can be omitted. The need to sustain representations of factual and suppositional events during counterfactual sentence processing requires increased mental imagery and integration efforts. Our findings are compatible with predictions based on mental model theory. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. On hypothetical bias and calibration in cost-benefit studies.

    Science.gov (United States)

    Liljas, B; Blumenschein, K

    2000-05-01

    Despite a sound foundation in economic welfare theory, willingness to pay (WTP) has not been used as a measure of benefits in economic evaluations of health and health care to the same extent as in other fields. Some have suggested that this is due to non-economists' reluctance to placing dollar values on the benefits of health care. However, another potential reason could be uncertainties about the validity of the WTP measure. In this paper, we outline the bias problems with the WTP method, and specifically focus on hypothetical bias; i.e. whether the WTP from hypothetical elicitation methods overstates the real WTP or not. This is done by examining the literature in this field, with emphasis on economic experiments where there is a greater possibility for comparison. The findings are that hypothetical WTP in general significantly overestimates real WTP, but that calibration methods to reduce or eliminate this difference are currently being developed. We conclude that while the area is still very much under development, there seem to be reasons to view the use of cost-benefit analysis as a reasonable alternative to the more common cost-effectiveness analysis.

  14. Hypothetical contractarianism and the disclosure requirement problem in informed consent.

    Science.gov (United States)

    Cust, Kenneth F T

    1991-01-01

    Two of the more deeply problematic issues surrounding the doctrine of informed consent are providing a justification for the practice of informed consent and providing an account of the nature and amount of information that must be disclosed in order for informed consent to take place. This paper is concerned with the latter problem, the problem of disclosure requirements, but it deals with this problem in a novel way; it approaches the problem by asking what fully informed and fully rational agents would agree to under certain hypothetical conditions. In general terms I juxtapose the hypothetical contractarianism found in Rawls' A Theory of Justice with that found in Gauthier's Morals By Agreement and ask what their respective hypothetical contractors would agree to with respect to choosing a particular standard of disclosure to govern the practice of informed consent. In more specific terms a contrast is made between what a Rawlsian agent behind a veil of ignorance would choose as compared to what, in Gauthier's terms, an ideal actor making an Archimedean choice would choose. The idea of an Archimedean point, and the subsequent choice made from that point, although technically identified by Rawls, originated with Archimedes of Syracuse.

  15. Epidemic dynamics on complex networks

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tao; FU Zhongqian; WANG Binghong

    2006-01-01

    Recently, motivated by the pioneer work in revealing the small-world effect and scale-free property of various real-life networks, many scientists devote themselves to studying complex networks. One of the ultimate goals is to understand how the topological structures affect the dynamics upon networks. In this paper, we give a brief review on the studies of epidemic dynamics on complex networks, including the description of classical epidemic models, the epidemic spread on small-world and scale-free networks, and network immunization. Finally, perspectives and some interesting problems are proposed.

  16. Epidemic Diffusion on Complex Networks

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-Yan; LIU Zong-Hua

    2007-01-01

    Boyh diffusion and epidemic are well studied in the stochastic systems and complex networks,respetively.Here we combine these two fields and study epidemic diffusion in complex networks.Instead of studying the threshold of infection,which was focused on in previous works,we focus on the diffusion.behaviour.We find that the epidemic diffusion in a complex network is an anomalous superdiffusion with varyingg diffusion exponext γand that γ is influenced seriously by the network structure,such as the clustering coefficient and the degree distribution.Numerical simulations have confirmed the theoretical predictions.

  17. Information Spreading in Epidemics and in Communication Networks

    DEFF Research Database (Denmark)

    Uekermann, Florian Philipp

    The PhD thesis revolves mainly around models of disease spreading and human behavior. We present models for different epidemic patterns of infectious diseases. This includes investigations of the trajectory of the 2014 Ebola outbreak in West-Africa, influenza evolution and the seasonal dynamics...

  18. Information Spreading in Epidemics and in Communication Networks

    DEFF Research Database (Denmark)

    Uekermann, Florian Philipp

    The PhD thesis revolves mainly around models of disease spreading and human behavior. We present models for different epidemic patterns of infectious diseases. This includes investigations of the trajectory of the 2014 Ebola outbreak in West-Africa, influenza evolution and the seasonal dynamics o...

  19. Epidemic Dynamics On Information-Driven Adaptive Networks

    CERN Document Server

    Zhan, Xiu-Xiu; Sun, Gui-Quan; Zhang, Zi-Ke

    2015-01-01

    can evolve simultaneously. For the information-driven adaptive process, susceptible (infected) individuals who have abilities to recognize the disease would break the links of their infected (susceptible) neighbors to prevent the epidemic from further spreading. Simulation results and numerical analyses based on the pairwise approach indicate that the information-driven adaptive process can not only slow down the speed of epidemic spreading, but can also diminish the epidemic prevalence at the final state significantly. In addition, the disease spreading and information diffusion pattern on the lattice give a visual representation about how the disease is trapped into an isolated field with the information-driven adaptive process. Furthermore, we perform the local bifurcation analysis on four types of dynamical regions, including healthy, oscillatory, bistable and endemic, to understand the evolution of the observed dynamical behaviors. This work may shed some lights on understanding how information affects h...

  20. Predicting epidemic outbreak from individual features of the spreaders

    CERN Document Server

    da Silva, Renato Aparecido Pimentel; Costa, Luciano da Fontoura

    2012-01-01

    Knowing which individuals can be more efficient in spreading a pathogen throughout a determinate environment is a fundamental question in disease control. Indeed, over the last years the spread of epidemic diseases and its relationship with the topology of the involved system have been a recurrent topic in complex network theory, taking into account both network models and real-world data. In this paper we explore possible correlations between the heterogeneous spread of an epidemic disease governed by the susceptible-infected-recovered (SIR) model, and several attributes of the originating vertices, considering Erd\\"os-R\\'enyi (ER), Barab\\'asi-Albert (BA) and random geometric graphs (RGG), as well as a real case of study, the US Air Transportation Network that comprises the US 500 busiest airports along with inter-connections. Among both the theoretical and the real networks considered, we observe high correlation between the total epidemic prevalence and the degree, the strength and the accessibility of the...

  1. Temporal prediction of epidemic patterns in community networks

    CERN Document Server

    Peng, Xiao-Long; Xu, Xin-Jian; Fu, Xinchu

    2013-01-01

    Most previous studies of epidemic dynamics on complex networks suppose that the disease will eventually stabilize at either a disease-free state or an endemic one. In reality, however, some epidemics always exhibit sporadic and recurrent behaviour in one region because of the invasion from an endemic population elsewhere. In this paper we address this issue and study a susceptible-infected-susceptible epidemiological model on a network consisting of two communities, where the disease is endemic in one community but alternates between outbreaks and extinctions in the other. We provide a detailed characterization of the temporal dynamics of epidemic patterns in the latter community. In particular, we investigate the time duration of both outbreak and extinction, and the time interval between two consecutive inter-community infections, as well as their frequency distributions. Based on the mean-field theory, we theoretically analyze these three timescales and their dependence on the average node degree of each c...

  2. SARS epidemical forecast research in mathematical model

    Institute of Scientific and Technical Information of China (English)

    DING Guanghong; LIU Chang; GONG Jianqiu; WANG Ling; CHENG Ke; ZHANG Di

    2004-01-01

    The SIJR model, simplified from the SEIJR model, is adopted to analyze the important parameters of the model of SARS epidemic such as the transmission rate, basic reproductive number. And some important parameters are obtained such as the transmission rate by applying this model to analyzing the situation in Hong Kong, Singapore and Canada at the outbreak of SARS. Then forecast of the transmission of SARS is drawn out here by the adjustment of parameters (such as quarantined rate) in the model. It is obvious that inflexion lies on the crunode of the graph, which indicates the big difference in transmission characteristics between the epidemic under control and not under control. This model can also be used in the comparison of the control effectiveness among different regions. The results from this model match well with the actual data in Hong Kong, Singapore and Canada and as a by-product, the index of the effectiveness of control in the later period can be acquired. It offers some quantitative indexes, which may help the further research in epidemic diseases.

  3. [Fight against epidemics: Austrian prisoners in Troyes].

    Science.gov (United States)

    Hetzel, Géraldine

    2014-01-01

    The victories near Ulm and Elchingen, where the Napoleonic army took 60000 prisoners between 15th and 20th of October 1805, lead to the arrival at Troyes (county "Aube") of nearly 2000 Austrian soldiers to be held inside former monasteries among whose, mainly the Jacobinians casern where more than half of them stayed. At the beginning of 1806, the government sent the epidemics medical practitioner Dr Desgenettes on an inspection tour to control the state of health of the populations of places where foreign prisoners were held, which lead him through several counties of the North-eastern part of France, where he surveyed several diseases ranging from all kinds offevers up to dysentery, scabies or gangrenes. With the means of acid fumigations invented by the chemist Guyton Morveau from Dijon, the authorities took care of combating and preventing the epidemics in the caserns. As soon as October 1805, the epidemics medical practitioner Dr Pigeotte from Troyes wrote to the county governor his observations recommending a better diet, airing of the rooms and also calls to take some exercise. All these precepts showed an astonishing modernity.

  4. Understanding the Opioid Overdose Epidemic

    Science.gov (United States)

    ... can happen when someone takes more than prescribed, combines opioids with depressants (such as Xanax ® ) or alcohol, ... suffering with chronic pain.” Read More "Understanding Opioids" Articles Understanding The Opioid Overdose Epidemic / Beyond Opioids: Mind ...

  5. Epidemic Forecasting is Messier Than Weather Forecasting: The Role of Human Behavior and Internet Data Streams in Epidemic Forecast.

    Science.gov (United States)

    Moran, Kelly R; Fairchild, Geoffrey; Generous, Nicholas; Hickmann, Kyle; Osthus, Dave; Priedhorsky, Reid; Hyman, James; Del Valle, Sara Y

    2016-12-01

    Mathematical models, such as those that forecast the spread of epidemics or predict the weather, must overcome the challenges of integrating incomplete and inaccurate data in computer simulations, estimating the probability of multiple possible scenarios, incorporating changes in human behavior and/or the pathogen, and environmental factors. In the past 3 decades, the weather forecasting community has made significant advances in data collection, assimilating heterogeneous data steams into models and communicating the uncertainty of their predictions to the general public. Epidemic modelers are struggling with these same issues in forecasting the spread of emerging diseases, such as Zika virus infection and Ebola virus disease. While weather models rely on physical systems, data from satellites, and weather stations, epidemic models rely on human interactions, multiple data sources such as clinical surveillance and Internet data, and environmental or biological factors that can change the pathogen dynamics. We describe some of similarities and differences between these 2 fields and how the epidemic modeling community is rising to the challenges posed by forecasting to help anticipate and guide the mitigation of epidemics. We conclude that some of the fundamental differences between these 2 fields, such as human behavior, make disease forecasting more challenging than weather forecasting. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  6. An online operational rainfall-monitoring resource for epidemic malaria early warning systems in Africa

    Science.gov (United States)

    Grover-Kopec, Emily; Kawano, Mika; Klaver, Robert W.; Blumenthal, Benno; Ceccato, Pietro; Connor, Stephen J.

    2005-01-01

    Periodic epidemics of malaria are a major public health problem for many sub-Saharan African countries. Populations in epidemic prone areas have a poorly developed immunity to malaria and the disease remains life threatening to all age groups. The impact of epidemics could be minimized by prediction and improved prevention through timely vector control and deployment of appropriate drugs. Malaria Early Warning Systems are advocated as a means of improving the opportunity for preparedness and timely response.

  7. Epidemics of Sirs Model with Nonuniform Transmission on Scale-Free Networks

    Science.gov (United States)

    Xia, C. Y.; Sun, S. W.; Liu, Z. X.; Chen, Z. Q.; Yuan, Z. Z.

    We investigate the effect of nonuniform transmission on the critical threshold of susceptible-infected-recovered-susceptible (SIRS) epidemic model on scale-free networks. Based on the mean-field theory, it is observed that the epidemic threshold is not only correlated with the topology of underlying networks, but also with the disease transmission mechanism (e.g., nonuniform transmission). The current findings will significantly help us to further understand the real epidemics taking place on social and technological networks.

  8. Epidemic spreading in complex networks

    Institute of Scientific and Technical Information of China (English)

    Jie ZHOU; Zong-hua LIU

    2008-01-01

    The study of epidemic spreading in complex networks is currently a hot topic and a large body of results have been achieved.In this paper,we briefly review our contributions to this field,which includes the underlying mechanism of rumor propagation,the epidemic spreading in community networks,the influence of varying topology,and the influence of mobility of agents.Also,some future directions are pointed out.

  9. Epidemic Network Failures in Optical Transport Networks

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Katsikas, Dimitrios; Fagertun, Anna Manolova

    2013-01-01

    This paper presents a failure propagation model for transport networks which are affected by epidemic failures. The network is controlled using the GMPLS protocol suite. The Susceptible Infected Disabled (SID) epidemic model is investigated and new signaling functionality of GMPLS to support epid...... epidemic failure resolution is proposed. The results provide important input to service recovery mechanisms under epidemic failures....

  10. Prevention--a cost-effective way to fight the non-communicable disease epidemic: an academic perspective of the United Nations High-level NCD Meeting.

    Science.gov (United States)

    Probst-Hensch, Nicole; Tanner, Marcel; Kessler, Claudia; Burri, Christian; Künzli, Nino

    2011-09-07

    The United Nations General Assembly has convened a Summit on non-communicable diseases (NCDs), an historic moment in the global combat of these disorders. Lifestyles in increasingly urban and globalised environments have led to a steep surge in NCD incidence in low and middle income countries, where two thirds of all NCD deaths occur (most importantly from cancer, cardiovascular and respiratory disease as well as diabetes). Treatment of NCDs is usually long term and expensive, thus threatening patients' and nations' budgets and putting them at high risk for poverty. The NCD Summit offers an opportunity for strengthening and shaping primary prevention, the most cost-effective instrument to fight major risk factors such as tobacco smoking, alcohol abuse, physical inactivity and unhealthy diet. From a Swiss perspective, we also emphasised the efforts for new laws on prevention and diagnosis registration, in accordance with the recommendations of the NCD summit in order to strengthen primary prevention and disease monitoring. In addition, the need for structural prevention across all policy sectors with leadership in environmental policy making to prevent NCDs as well as the need to adapt and strengthen primary health care are equally relevant for Switzerland. To compliment efforts in primary prevention, the field of NCDs requires special R&D platforms for affordable NCD drugs and diagnostics for neglected population segments in both Switzerland and low and middle income countries. Switzerland has a track record in research and development against diseases of poverty on a global scale that now needs to be applied to NCDs.

  11. Parasite transmission in social interacting hosts: Monogenean epidemics in guppies

    Science.gov (United States)

    Johnson, Mirelle B.; Lafferty, Kevin D.; van Oosterhout, Cock; Cable, Joanne

    2011-01-01

    Background Infection incidence increases with the average number of contacts between susceptible and infected individuals. Contact rates are normally assumed to increase linearly with host density. However, social species seek out each other at low density and saturate their contact rates at high densities. Although predicting epidemic behaviour requires knowing how contact rates scale with host density, few empirical studies have investigated the effect of host density. Also, most theory assumes each host has an equal probability of transmitting parasites, even though individual parasite load and infection duration can vary. To our knowledge, the relative importance of characteristics of the primary infected host vs. the susceptible population has never been tested experimentally. Methodology/Principal Findings Here, we examine epidemics using a common ectoparasite, Gyrodactylus turnbulli infecting its guppy host (Poecilia reticulata). Hosts were maintained at different densities (3, 6, 12 and 24 fish in 40 L aquaria), and we monitored gyrodactylids both at a population and individual host level. Although parasite population size increased with host density, the probability of an epidemic did not. Epidemics were more likely when the primary infected fish had a high mean intensity and duration of infection. Epidemics only occurred if the primary infected host experienced more than 23 worm days. Female guppies contracted infections sooner than males, probably because females have a higher propensity for shoaling. Conclusions/Significance These findings suggest that in social hosts like guppies, the frequency of social contact largely governs disease epidemics independent of host density.

  12. [Cholera epidemics in Mali between 1995 and 2004].

    Science.gov (United States)

    Dao, Sounkalo; Konaté, Issa; Oumar, Aboubacar Alassane; Sacko, Massambou; Maiga, Ibrahim; Toure, Kandioura; Diarra, Seydou; Bougoudogo, Flabou

    2009-01-01

    Cholera represents a public health problem in developing countries like Mali. This work aims to describe the characteristics of the cholera epidemics which occurred in Mali between 1995 and 2004. A retrospective survey was conducted within the Division of the fight against the diseases of epidemic potential and the Institute of Public Health and Research of the Ministry of Health of Mali. Individual medical records tracking the follow-up of patients as well as the registers of these structures were used as sources to collect data for the study. There were 12,176 cases of cholera recorded, including 1,406 deaths, from 1995 to 2004. Cholera outbreaks in Mali have been a regular occurrence every year since 2001. The regions of Mopti and Segou seem to be the most impacted by these epidemics. The lethal rates were higher than 1% at the time of each of these epidemics during this period. Vibrio cholerae O: 1, biotype El Tor were responsible for the epidemics, and the serotype Ogawa was prevalent. Cholera epidemics have been constant in Mali since the beginning of the 21st century in spite of the efforts which have been made to prevent and control them. A rigorous analysis of the factors which support this persistence and appropriate measures are essential to reverse cholera in this country.

  13. Parasite transmission in social interacting hosts: monogenean epidemics in guppies.

    Directory of Open Access Journals (Sweden)

    Mirelle B Johnson

    Full Text Available BACKGROUND: Infection incidence increases with the average number of contacts between susceptible and infected individuals. Contact rates are normally assumed to increase linearly with host density. However, social species seek out each other at low density and saturate their contact rates at high densities. Although predicting epidemic behaviour requires knowing how contact rates scale with host density, few empirical studies have investigated the effect of host density. Also, most theory assumes each host has an equal probability of transmitting parasites, even though individual parasite load and infection duration can vary. To our knowledge, the relative importance of characteristics of the primary infected host vs. the susceptible population has never been tested experimentally. METHODOLOGY/PRINCIPAL FINDINGS: Here, we examine epidemics using a common ectoparasite, Gyrodactylus turnbulli infecting its guppy host (Poecilia reticulata. Hosts were maintained at different densities (3, 6, 12 and 24 fish in 40 L aquaria, and we monitored gyrodactylids both at a population and individual host level. Although parasite population size increased with host density, the probability of an epidemic did not. Epidemics were more likely when the primary infected fish had a high mean intensity and duration of infection. Epidemics only occurred if the primary infected host experienced more than 23 worm days. Female guppies contracted infections sooner than males, probably because females have a higher propensity for shoaling. CONCLUSIONS/SIGNIFICANCE: These findings suggest that in social hosts like guppies, the frequency of social contact largely governs disease epidemics independent of host density.

  14. Porcine epidemic diarrhea virus infection: Etiology, epidemiology, pathogenesis and immunoprophylaxis.

    Science.gov (United States)

    Jung, Kwonil; Saif, Linda J

    2015-05-01

    Porcine epidemic diarrhea virus (PEDV), a member of the genera Alphacoronavirus in the family Coronaviridae, causes acute diarrhea/vomiting, dehydration and high mortality in seronegative neonatal piglets. For the last three decades, PEDV infection has resulted in significant economic losses in the European and Asian pig industries, but in 2013-2014 the disease was also reported in the US, Canada and Mexico. The PED epidemic in the US, from April 2013 to the present, has led to the loss of more than 10% of the US pig population. The disappearance and re-emergence of epidemic PED indicates that the virus is able to escape from current vaccination protocols, biosecurity and control systems. Endemic PED is a significant problem, which is exacerbated by the emergence (or potential importation) of multiple PEDV variants. Epidemic PEDV strains spread rapidly and cause a high number of pig deaths. These strains are highly enteropathogenic and acutely infect villous epithelial cells of the entire small and large intestines although the jejunum and ileum are the primary sites. PEDV infections cause acute, severe atrophic enteritis accompanied by viremia that leads to profound diarrhea and vomiting, followed by extensive dehydration, which is the major cause of death in nursing piglets. A comprehensive understanding of the pathogenic characteristics of epidemic or endemic PEDV strains is needed to prevent and control the disease in affected regions and to develop an effective vaccine. This review focuses on the etiology, epidemiology, disease mechanisms and pathogenesis as well as immunoprophylaxis against PEDV infection.

  15. An epidemic of influenza on Tristan da Cunha.

    Science.gov (United States)

    Mantle, J; Tyrrell, D A

    1973-03-01

    Respiratory disease on Tristan da Cunha has been observed since the islanders returned in 1962. An epidemic of unprecedented severity occurred in the winter of 1971 and involved 273 (96%) of 284 islanders, 92 of whom had two attacks.The epidemic was apparently introduced by the Tristania.The illness of both first and second attacks ranged from mild to severe but there were some differences. There were two deaths, both in elderly persons with chronic chest disease and heart failure. Serological evidence suggests that this was due to influenza A2 of the Hong Kong serotype H(3)N(2).

  16. Many-body methods in agent-based epidemic models

    CERN Document Server

    Nakamura, Gilberto M

    2016-01-01

    The susceptible-infected-susceptible (SIS) agent-based model is usually employed in the investigation of epidemics. The model describes a Markov process for a single communicable disease among susceptible (S) and infected (I) agents. However, the disease spreading forecasting is often restricted to numerical simulations, while analytic formulations lack both general results and perturbative approaches since they are subjected to asymmetric time generators. Here, we discuss perturbation theory, approximations and application of many-body techniques in epidemic models in the framework for squared norm of probability vector $|P(t)| ^2$, in which asymmetric time generators are replaced by their symmetric counterparts.

  17. Demand Curves for Hypothetical Cocaine in Cocaine-Dependent Individuals

    Science.gov (United States)

    Bruner, Natalie R.; Johnson, Matthew W.

    2013-01-01

    Rationale Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. Objectives This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Methods Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Results Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and Omax (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, Pmax, were significantly correlated with real-world cocaine use. Conclusions Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use. PMID:24217899

  18. Demand curves for hypothetical cocaine in cocaine-dependent individuals.

    Science.gov (United States)

    Bruner, Natalie R; Johnson, Matthew W

    2014-03-01

    Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks, drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and O max (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, P max, were significantly correlated with real-world cocaine use. Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use.

  19. Constraints on hypothetical counterexamples to the Casas-Alvero conjecture

    CERN Document Server

    Laterveer, Robert

    2012-01-01

    The Casas-Alvero conjecture states: if a complex univariate polynomial has a common root with each of its derivatives, then it has a unique root. We show that hypothetical counterexamples must have at least 5 different roots. The first case where the conjecture is not known is in degree 12. We study the case of degree 12, and more generally degree p+1, where p is a prime number. While we don't come closing to solving the conjecture in degree 12, we present several further constraints that counterexamples would have to satisfy.

  20. Search for the hypothetical $\\pi$ -> $\\mu$ + x decay

    CERN Document Server

    Bilger, R; Denig, A; Föhl, K; Hautle, P; Kluge, W; Konter, J A; Kurz, G; Mango, S; Schapler, D; Schonleber, F; Siodlaczek, U; Van den Brandt, B; Wagner, G J; Wieser, R

    1995-01-01

    The KARMEN collaboration has reported the possible observation of a hitherto unknown neutral and weakly interacting particle x, which is produced in the decay pi -> mu + x with a mass m(x) = 33.9 MeV. We have searched for this hypothetical decay branch by studying muons from pion decay in flight with the LEPS spectrometer at the piE3 channel at PSI and find branching ratios BR(pi- to mu- anti-x) 2e-8 derived in a recent theoretical paper our result would leave only a narrow region for the existence of x if it is a heavy neutrino.

  1. Consequences of a hypothetical incident for different sectors

    CERN Document Server

    Bertinelli, F; Garion, C; Jimenez, J M; Parma, V; Perin, A; Schmidt, R; Tavian, L; Tock, J P; van Weelderen, R

    2011-01-01

    During the 2009 long shutdown, the LHC machine has been partially consolidated by adding safety relief devices in order to better protect the cryostats against large helium release and consequently to mitigate the risks of collateral damages. After recalling the present relief valve implementation and other mitigations related to the collateral damages, this paper describes the damage process of a hypothetical incident, presents its consequences for the different sectors and for beam energies up to 5 TeV with emphasis on the induced downtime.

  2. Estimating Potential Effects of Hypothetical Oil Spills on Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Durner, G.M.; McDonald, T.L.; Johnson, W.R.

    2006-01-01

    Much is known about the transport and fate of oil spilled into the sea and its toxicity to exposed wildlife. Previously, however, there has been no way to quantify the probability that wildlife dispersed over the seascape would be exposed to spilled oil. Polar bears, the apical predator of the arctic, are widely dispersed near the continental shelves of the Arctic Ocean, an area also undergoing considerable hydrocarbon exploration and development. We used 15,308 satellite locations from 194 radiocollared polar bears to estimate the probability that polar bears could be exposed to hypothetical oil spills. We used a true 2 dimensional Gausian kernel density estimator, to estimate the number of bears likely to occur in each 1.00 km2 cell of a grid superimposed over near shore areas surrounding 2 oil production facilities: the existing Northstar oil production facility, and the proposed offshore site for the Liberty production facility. We estimated the standard errors of bear numbers per cell with bootstrapping. Simulated oil spill footprints for September and October, the times during which we hypothesized effects of an oil-spill would be worst, were estimated using real wind and current data collected between 1980 and 1996. We used ARC/Info software to calculate overlap (numbers of bears oiled) between simulated oil-spill footprints and polar bear grid-cell values. Numbers of bears potentially oiled by a hypothetical 5912 barrel spill (the largest spill thought probable from a pipeline breach) ranged from 0 to 27 polar bears for September open water conditions, and from 0 to 74 polar bears in October mixed ice conditions. Median numbers oiled by the 5912 barrel hypothetical spill from the Liberty simulation in September and October were 1 and 3 bears, equivalent values for the Northstar simulation were 3 and 11 bears. In October, 75% of trajectories from the 5912 barrel simulated spill at Liberty oiled 9 or fewer bears while 75% of the trajectories affected 20 or

  3. Effects of hypothetical improvised nuclear detonation on the electrical infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Christopher L.; Eubank, Stephen; Evrenosoglu, C. Yaman; Marathe, Achla; Marathe, Madhav V.; Phadke, Arun; Thorp, James; Vullikanti, Anil [Virginia Tech, Blacksburg, VA (United States). Network Dynamics and Simulation Science Lab.

    2013-07-01

    We study the impacts of a hypothetical improvised nuclear detonation (IND) on the electrical infrastructure and its cascading effects on other urban inter-dependent infrastructures of a major metropolitan area in the US. We synthesize open source information, expert knowledge, commercial software and Google Earth data to derive a realistic electrical transmission and distribution network spanning the region. A dynamic analysis of the geo-located grid is carried out to determine the cause of malfunction of components, and their short-term and long-term effect on the stability of the grid. Finally a detailed estimate of the cost of damage to the major components of the infrastructure is provided.

  4. Point-of-Care Diagnostics in Low-Resource Settings and Their Impact on Care in the Age of the Noncommunicable and Chronic Disease Epidemic.

    Science.gov (United States)

    Weigl, Bernhard H; Neogi, Tina; McGuire, Helen

    2014-06-01

    The emergence of point-of-care (POC) diagnostics specifically designed for low-resource settings coupled with the rapid increase in need for routine care of patients with chronic diseases should prompt reconsideration of how health care can be delivered most beneficially and cost-effectively in developing countries. Bolstering support for primary care to provide rapid and appropriate integrated acute and chronic care treatment may be a possible solution. POC diagnostics can empower local and primary care providers and enable them to make better clinical decisions. This article explores the opportunity for POC diagnostics to strengthen primary care and chronic disease diagnosis and management in a low-resource setting (LRS) to deliver appropriate, consistent, and integrated care. We analyze the requirements of resource-appropriate chronic disease care, the characteristics of POC diagnostics in LRS versus the developed world, the many roles of diagnostics in the care continuum in LRS, and the process and economics of developing LRS-compatible POC diagnostics.

  5. [Study on willingness to participate and willingness to pay for hypothetical industrial injury insurance scheme].

    Science.gov (United States)

    Wu, Yuan; Dong, Hengjin; Duan, Shengnan; Liu, Xiaofang; Ye, Chiyu; You, Hua; Hu, Huimei; Wang, Linhao; Zhang, Xing; Wang, Jing

    2014-10-01

    To investigate workers' willingness to participate and wiliness to pay for a hypothetical industrial injury insurance scheme, to analyze the influential factors, and to provide information for policy making of the government. Multistage cluster sampling was used to select subjects: In the first stage, 9 small, medium, orlarge enterprises were selected fromthree cities (counties) in Zhejiang province, China, according to the level of economic development, transportation convenience, and cooperation of government agencies; in the second stage, several workshops were randomly selected from each of the 9 enterprises. Face-to-face interviews among all workers in the workshops were conducted by trained interviewers using a pre-designed questionnaire. It was found that 73.87% (2095) of all workers were willing to participate in the hypothetical work injury insurance scheme and to pay 2.21% of monthly wage (51.77 yuan) on average, and more than half of the workers were willing to pay less than 1%of monthly wage (35 yuan). Of the 741 workers who were not willing to participate, 327 thought that the premium should be borne by the state or enterprises, instead of individuals, and others were not willing to participate because of low income, unstable job, or poor understanding of the hypothetical industrial injury insurance scheme. Logistic regression analysis showed that workers with higher education levels, longer length of services, longer weekly working time, or more knowledge of occupational diseases showed higher willingness to participate in the scheme; workers who were exposed to physical hazards, had health records, or had participated in the existing medical insurance or industrial injury insurance were more willing to participate. Multiple linear regression analysis showed that with increasing average monthly wage, weekly working time, and self?health evaluation, the proportion of workers with willingness to pay increased; however, with increasing work intensity and

  6. Improving epidemic control strategies by extended detection

    Science.gov (United States)

    Karp, Paweł; Dybiec, Bartłomiej; Kleczkowski, Adam

    2014-11-01

    Majority of epidemics eradication programs work in preventive responsive way. The lack of exact information about epidemiological status of individuals makes responsive actions less efficient. Here, we demonstrate that additional tests can significantly increase the efficiency of "blind" treatment (vaccination or culling). Eradication strategy consisting of "blind" treatment in very limited local neighborhood supplemented by extra tests in a little bit larger neighborhood is able to prevent invasion of even highly infectious diseases and to achieve this at a cost lower than for the "blind" strategy. The effectiveness of the extended strategy depends on such parameters as the test efficiency and test cost.

  7. Hydro-epidemiology of Chronic Kidney Disease(CKD) in Sri Lanka and Its Similarities to the CKD Epidemic in Meso-America.Sarath Gunatilake M.D, Dr. P.H, Professor, California State University, Long Beach California

    Science.gov (United States)

    Illangasekera, T.; Gunatilake, S.

    2015-12-01

    Over 2000 years ago Sri Lanka was known as the granary of the east. This distinction was achieved with a massive rice production aided by an efficient irrigation system. The basic structural unit of this irrigation system -with thousands of man-made lakes- was a large reservoir collecting rain water from tributaries and redistributing it to a cascade of rice paddy farms. The rice cultivation used organic fertilizer and natural pesticides made from ancient Ayurvedic recipes. The sociopolitical changes initiated in the county in 1977 resulted in a modernized agricultural economy with the renovation of the old irrigation system. Heavy use of pesticides, mostly Glyphosate (brand name "Round Up") with government subsidized cheap synthetic fertilizer (mostly triple phosphate) contaminated with heavy metals, including Arsenic and Cadmium, became a common practice. As a result, the shallow aquifers in the lowest lying areas, recharged by the irrigation water, was contaminated with Calcium, Magnesium phosphates, and the heavy metals, rendering the drinking water from shallow wells in these areas, extremely hard and unpalatable. The practice of drinking water from the shallow wells in low lying areas, most of which are abandoned now, and the use and spraying of pesticides particularly Glyphosate (often without proper personal protective equipment) have been identified in a case control study, as the main risk factors responsible for a massive epidemic of Chronic Kidney Disease (CKD) affecting 450,000 young farmers, resulting in 23,000 deaths. It is hypothesized that the Glyphosate chelates heavy metals delivering it to the kidney, with contaminated drinking water and food, causing progressive kidney damage. The same irrigation system that contributed to past prosperity has now become a scourge within the realm of a modernized agriculture. Climatic variations, global warming and severe dehydration also have been identified as contributory factors. Similar CKD epidemic killing

  8. Resource allocation for epidemic control in metapopulations.

    Directory of Open Access Journals (Sweden)

    Martial L Ndeffo Mbah

    Full Text Available Deployment of limited resources is an issue of major importance for decision-making in crisis events. This is especially true for large-scale outbreaks of infectious diseases. Little is known when it comes to identifying the most efficient way of deploying scarce resources for control when disease outbreaks occur in different but interconnected regions. The policy maker is frequently faced with the challenge of optimizing efficiency (e.g. minimizing the burden of infection while accounting for social equity (e.g. equal opportunity for infected individuals to access treatment. For a large range of diseases described by a simple SIRS model, we consider strategies that should be used to minimize the discounted number of infected individuals during the course of an epidemic. We show that when faced with the dilemma of choosing between socially equitable and purely efficient strategies, the choice of the control strategy should be informed by key measurable epidemiological factors such as the basic reproductive number and the efficiency of the treatment measure. Our model provides new insights for policy makers in the optimal deployment of limited resources for control in the event of epidemic outbreaks at the landscape scale.

  9. Mass Gathering Medicine New discipline to Deal with Epidemic and Infectious Diseases in the Hajj Among Muslim Pilgrimage: A Mini Review Article.

    Science.gov (United States)

    Al Turki, Yousef Abdullah

    2016-08-01

    Mass Gathering Medicine is one of the new disciplines in Medicine which deal with all health aspects in overcrowded areas. Mass Gathering Medicine is an important new challenging discipline which needs to be supported by all concern experts such as the World Health Organization, Centers for Disease Control and Prevention, ministries of health from all countries, universities, research centers, and all other experts in this field. Scientist and academic staffs from all countries should be encouraged to participate in narrowing the gap of knowledge for Mass Gathering Medicine. Postgraduate board or fellowship certificate should be encouraged internationally.

  10. Could the Recent Zika Epidemic Have Been Predicted?

    Directory of Open Access Journals (Sweden)

    Ángel G. Muñoz

    2017-07-01

    Full Text Available Given knowledge at the time, the recent 2015–2016 zika virus (ZIKV epidemic probably could not have been predicted. Without the prior knowledge of ZIKV being already present in South America, and given the lack of understanding of key epidemiologic processes and long-term records of ZIKV cases in the continent, the best related prediction could be carried out for the potential risk of a generic Aedes-borne disease epidemic. Here we use a recently published two-vector basic reproduction number model to assess the predictability of the conditions conducive to epidemics of diseases like zika, chikungunya, or dengue, transmitted by the independent or concurrent presence of Aedes aegypti and Aedes albopictus. We compare the potential risk of transmission forcing the model with the observed climate and with state-of-the-art operational forecasts from the North American Multi Model Ensemble (NMME, finding that the predictive skill of this new seasonal forecast system is highest for multiple countries in Latin America and the Caribbean during the December-February and March-May seasons, and slightly lower—but still of potential use to decision-makers—for the rest of the year. In particular, we find that above-normal suitable conditions for the occurrence of the zika epidemic at the beginning of 2015 could have been successfully predicted at least 1 month in advance for several zika hotspots, and in particular for Northeast Brazil: the heart of the epidemic. Nonetheless, the initiation and spread of an epidemic depends on the effect of multiple factors beyond climate conditions, and thus this type of approach must be considered as a guide and not as a formal predictive tool of vector-borne epidemics.

  11. Elusive but not hypothetical: axillary meristems in Wollemia nobilis.

    Science.gov (United States)

    Burrows, Geoffrey E

    2012-01-01

    The branches of Wollemia nobilis are unbranched; however, it has been noted that new branches can form from the distal end of damaged ones, and branches can grow from axillary structures once a terminal strobilus has fallen. Tomlinson and Huggett (2011, Annals of Botany 107: 909-916) have recently investigated the formation of these reiterative branches and stated in the title of their paper that 'Partial shoot reiteration in Wollemia nobilis (Araucariaceae) does not arise from "axillary meristems"'. They go on to state 'Further research may reveal the presence of these elusive, but still only hypothetical, axillary meristems'. In this Viewpoint, I argue that Tomlinson and Huggett do not refer to previously published information that indicates that axillary meristems are present in Wollemia nobilis branch leaf axils, and that their anatomical methods were probably not optimal for locating and examining these minute structures. Thus, whilst I would agree that the axillary meristems in branch leaf axils of Wollemia nobilis are elusive, I contend that they are not hypothetical.

  12. On the hypothetical utilization of atmospheric potential energy

    Directory of Open Access Journals (Sweden)

    Thomas Frisius

    2014-09-01

    Full Text Available Atmospheric potential energy is typically divided into an available and a nonavailable part. In this article a hypothetical utilization of a fraction of the nonavailable potential energy is described. This part stems from the water vapor that can be converted into the liquid phase. An energy gain results when the potential energy of the condensate relative to a reference height exceeds the energy necessary to condensate the water vapor. It is shown that this can be the case in a saturated atmosphere without convective available potential energy. Finally, simulations with the numerical cloud model HURMOD are performed to estimate the usability of the device in practice. Indeed, a positive energy output results in a simulation with immediate gathering of the condensate. On the contrary, potential energy gained falls significantly short of the necessary energy for forming the condensate when a realistic cloud microphysical scheme allowing re-evaporation of condensate is applied. Taken together it can be concluded that, a utilization of atmospheric potential energy is hypothetically possible but the practical realization is probably not feasible.

  13. Further tests of entreaties to avoid hypothetical bias in referendum contingent valuation

    Science.gov (United States)

    Thomas C. Brown; Icek Ajzen; Daniel Hrubes

    2003-01-01

    Over-estimation of willingness to pay in contingent markets has been attributed largely to hypothetical bias. One promising approach for avoiding hypothetical bias is to tell respondents enough about such bias that they self-correct for it. A script designed for this purpose by Cummings and Taylor was used in hypothetical referenda that differed in payment amount. In...

  14. Cholera epidemic threatens Sierra Leone.

    Science.gov (United States)

    Dyer, O

    1995-07-08

    Sierra Leone faces the threat of a major epidemic of cholera with the onset of the rainy season, according to the World Health Organization (WHO). The situation is particularly grave for the two million people displaced by the country's civil war. Already 1709 cases of cholera have been registered in Freetown, with 57 deaths. Freetown's population has doubled since the start of the war in 1991 with 750,000 refugees camping out in the town. The insurgent Revolutionary United Front is now within 32 km of the capital. Provinces are cut off from the capital, medical supplies are scarce. Doctors and aid workers are forced to rely on a private helicopter service for personal transport. As many as 10,000 people were affected by the disease last year. WHO experts predict that pneumonia is likely to claim the lives of many children, and a highly drug resistant strain of Plasmodium falciparum malaria is also looming. The greatest problems are the lack of safe drinking water and the attendant risks of cholera and dysentery. At one site in Freetown the 6000 refugees have to fetch water from a well and have no latrines. As a result there have been 277 cases of cholera and 2 deaths already among that group. The health department has set up five centers to treat cholera in Freetown and is organizing mobile clinics. WHO's Sierra Leone office is assisting the government mobile health teams, which provide free primary care to displaced people. Medicines and vaccines, however, are lacking. Many of the staff of the 13 district health authorities have been displaced to Freetown. Aid agencies such as Medecins Sans Frontieres and Oxfam have stepped into the role in many districts. Ironically, one of the Revolutionary United Front's main demands is for a free national health service.

  15. Phase diagram of epidemic spreading - unimodal vs. bimodal probability distributions

    CERN Document Server

    Lancic, Alen; Sikic, Mile; Stefancic, Hrvoje

    2009-01-01

    The disease spreading on complex networks is studied in SIR model. Simulations on empirical complex networks reveal two specific regimes of disease spreading: local containment and epidemic outbreak. The variables measuring the extent of disease spreading are in general characterized by a bimodal probability distribution. Phase diagrams of disease spreading for empirical complex networks are introduced. A theoretical model of disease spreading on m-ary tree is investigated both analytically and in simulations. It is shown that the model reproduces qualitative features of phase diagrams of disease spreading observed in empirical complex networks. The role of tree-like structure of complex networks in disease spreading is discussed.

  16. History, Epidemic Evolution, and Model Burn-In for a Network of Annual Invasion: Soybean Rust.

    Science.gov (United States)

    Sanatkar, M R; Scoglio, C; Natarajan, B; Isard, S A; Garrett, K A

    2015-07-01

    Ecological history may be an important driver of epidemics and disease emergence. We evaluated the role of history and two related concepts, the evolution of epidemics and the burn-in period required for fitting a model to epidemic observations, for the U.S. soybean rust epidemic (caused by Phakopsora pachyrhizi). This disease allows evaluation of replicate epidemics because the pathogen reinvades the United States each year. We used a new maximum likelihood estimation approach for fitting the network model based on observed U.S. epidemics. We evaluated the model burn-in period by comparing model fit based on each combination of other years of observation. When the miss error rates were weighted by 0.9 and false alarm error rates by 0.1, the mean error rate did decline, for most years, as more years were used to construct models. Models based on observations in years closer in time to the season being estimated gave lower miss error rates for later epidemic years. The weighted mean error rate was lower in backcasting than in forecasting, reflecting how the epidemic had evolved. Ongoing epidemic evolution, and potential model failure, can occur because of changes in climate, host resistance and spatial patterns, or pathogen evolution.

  17. Game theory of social distancing in response to an epidemic.

    Directory of Open Access Journals (Sweden)

    Timothy C Reluga

    2010-05-01

    Full Text Available Social distancing practices are changes in behavior that prevent disease transmission by reducing contact rates between susceptible individuals and infected individuals who may transmit the disease. Social distancing practices can reduce the severity of an epidemic, but the benefits of social distancing depend on the extent to which it is used by individuals. Individuals are sometimes reluctant to pay the costs inherent in social distancing, and this can limit its effectiveness as a control measure. This paper formulates a differential-game to identify how individuals would best use social distancing and related self-protective behaviors during an epidemic. The epidemic is described by a simple, well-mixed ordinary differential equation model. We use the differential game to study potential value of social distancing as a mitigation measure by calculating the equilibrium behaviors under a variety of cost-functions. Numerical methods are used to calculate the total costs of an epidemic under equilibrium behaviors as a function of the time to mass vaccination, following epidemic identification. The key parameters in the analysis are the basic reproduction number and the baseline efficiency of social distancing. The results show that social distancing is most beneficial to individuals for basic reproduction numbers around 2. In the absence of vaccination or other intervention measures, optimal social distancing never recovers more than 30% of the cost of infection. We also show how the window of opportunity for vaccine development lengthens as the efficiency of social distancing and detection improve.

  18. Game theory of social distancing in response to an epidemic.

    Science.gov (United States)

    Reluga, Timothy C

    2010-05-27

    Social distancing practices are changes in behavior that prevent disease transmission by reducing contact rates between susceptible individuals and infected individuals who may transmit the disease. Social distancing practices can reduce the severity of an epidemic, but the benefits of social distancing depend on the extent to which it is used by individuals. Individuals are sometimes reluctant to pay the costs inherent in social distancing, and this can limit its effectiveness as a control measure. This paper formulates a differential-game to identify how individuals would best use social distancing and related self-protective behaviors during an epidemic. The epidemic is described by a simple, well-mixed ordinary differential equation model. We use the differential game to study potential value of social distancing as a mitigation measure by calculating the equilibrium behaviors under a variety of cost-functions. Numerical methods are used to calculate the total costs of an epidemic under equilibrium behaviors as a function of the time to mass vaccination, following epidemic identification. The key parameters in the analysis are the basic reproduction number and the baseline efficiency of social distancing. The results show that social distancing is most beneficial to individuals for basic reproduction numbers around 2. In the absence of vaccination or other intervention measures, optimal social distancing never recovers more than 30% of the cost of infection. We also show how the window of opportunity for vaccine development lengthens as the efficiency of social distancing and detection improve.

  19. Status of vaccines for porcine epidemic diarrhea virus in the United States and Canada

    Science.gov (United States)

    In 2013, porcine epidemic diarrhea virus (PEDV) emerged in the United States as a rapidly spreading epidemic causing dramatic death losses in suckling piglets. Neonatal piglets are most vulnerable to clinical disease and their only protection is passive immunity from their dam. At the end of the thi...

  20. Epidemic Threats to the European Union: Expert Views on Six Virus Groups

    NARCIS (Netherlands)

    Kelly, L.; Brouwer, A.; Wilson, A.; Gale, P.; Snary, E.; Ross, D.; Vos, de C.J.

    2013-01-01

    In recent years, several animal disease epidemics have occurred within the European Union (EU). At the 4th Annual Meeting of the EPIZONE network (7-10 June 2010, St. Malo, France), an interactive session was run to elicit the opinions of delegates on a pre-defined list of epidemic threats to the EU.

  1. Epidemic spreading on evolving signed networks

    CERN Document Server

    Saeedian, M; Jafari, G R; Kertesz, J

    2016-01-01

    Most studies of disease spreading consider the underlying social network as obtained without the contagion, though epidemic influences peoples willingness to contact others: A friendly contact may be turned to unfriendly to avoid infection. We study the susceptible-infected (SI) disease spreading model on signed networks, in which each edge is associated with a positive or negative sign representing the friendly or unfriendly relation between its end nodes. In a signed network, according to Heiders theory, edge signs evolve such that finally a state of structural balance is achieved, corresponding to no frustration in physics terms. However, the danger of infection affects the evolution of its edge signs. To describe the coupled problem of the sign evolution and disease spreading, we generalize the notion of structural balance by taking into account the state of the nodes. We introduce an energy function and carry out Monte-Carlo simulations on complete networks to test the energy landscape, where we find loc...

  2. Real-time forecasts of dengue epidemics

    Science.gov (United States)

    Yamana, T. K.; Shaman, J. L.

    2015-12-01

    Dengue is a mosquito-borne viral disease prevalent in the tropics and subtropics, with an estimated 2.5 billion people at risk of transmission. In many areas with endemic dengue, disease transmission is seasonal but prone to high inter-annual variability with occasional severe epidemics. Predicting and preparing for periods of higher than average transmission is a significant public health challenge. Here we present a model of dengue transmission and a framework for optimizing model simulations with real-time observational data of dengue cases and environmental variables in order to generate ensemble-based forecasts of the timing and severity of disease outbreaks. The model-inference system is validated using synthetic data and dengue outbreak records. Retrospective forecasts are generated for a number of locations and the accuracy of these forecasts is quantified.

  3. Cholera: a continuous epidemic in Africa.

    Science.gov (United States)

    Naidoo, A; Patric, K

    2002-06-01

    Cholera continues to plague many parts of the world, but has largely been concentrated in Africa, which contributes more than 80% of the total cases worldwide. Natural disasters, like the 2000 floods in Mozambique and the volcanic eruption in the Democratic Republic of the Congo in 2002, generally lead to new outbreaks of the disease. The refugee problem in many countries throughout the world also causes potential threats for disease outbreaks. Case fatality rates are high, and we are not anywhere near curbing new cholera epidemics, especially in Africa. It is thus imperative to renew discussions about the nature of this deadly disease, its treatment, measures for prevention and control, modes of transmission, its physical, social and economic impact, and potential solutions.

  4. Porcine epidemic diarrhea virus: current insights

    Directory of Open Access Journals (Sweden)

    Lv C

    2016-05-01

    Full Text Available Chaochao Lv,1,* Yan Xiao,1,* Xiangdong Li,1 Kegong Tian,1,2 1National Research Center for Veterinary Medicine, Luoyang, People's Republic of China; 2College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China *These authors contributed equally to this review Abstract: Porcine epidemic diarrhea virus (PEDV, an enveloped, single-stranded, positive-sense RNA virus belonging to the genus Alphacoronavirus in the family Coronaviridae, can infect pigs of all ages and causes acute and watery diarrhea, vomiting, dehydration, and high mortality in neonatal piglets. This disease was first observed in England in 1971 and was subsequently reported in many swine-producing countries in Europe and Asia. In contrast to the situation in Europe, the disease has remained a major cause of diarrhea outbreaks on swine farms in Asia. Since late 2010, severe porcine epidemic diarrhea (PED epizootics caused by new variants have been affecting pigs in the People's Republic of China, resulting in substantial economic losses. In April 2013, PEDV was identified for the first time in the United States and resulted in the estimated death of over seven million piglets during a 1-year epidemic. Nowadays, it has spread into North and South America, Asia, and Europe, causing significant economic problems worldwide. More studies have been conducted in PEDV research, and the number of scientific literatures published during the last 5 years has exceeded the total of that in the past several decades. This review focuses on the current understanding of the etiology, molecular epidemiology, transmission, diagnosis, and pathogenesis of PEDV, as well as the vaccine to prevent PEDV infection. Keywords: PEDV, molecular epidemiology, transmission, diagnosis, pathogenesis, immune response, vaccine

  5. Epidemic trend of notifiable communicable diseases in Xishuangbanna, Yunnan,2004-2011%2004-2011年云南省西双版纳傣族自治州法定报告传染病疫情分析

    Institute of Scientific and Technical Information of China (English)

    申剑波

    2012-01-01

    目的 分析云南省西双版纳傣族自治州(西双版纳州)近8年法定传染病的流行特征,为制定防控措施提供依据.方法 采用描述性流行病学方法对2004 - 2011年《疾病监测信息报告管理系统》报告的法定传染病疫情资料进行分析.结果 2004-2011年全州无甲类传染病报告,报告乙类传染病18种共30 511例,死亡324例,年均发病率为365.62/10万,年均死亡率为3.81/10万.居乙类传染病前5位的病种依次为病毒性肝炎、肺结核、伤寒和副伤寒、疟疾和痢疾,占传染病报告总数的83.57%.2005年发生输入性登革热病例,2008年发生首例狂犬病病例,2010年发生本地感染登革热病例.结论 8年间西双版纳州传染病发病率总体呈下降趋势,病毒性肝炎、肺结核、伤寒和副伤寒、性传播疾病、新发传染病和境外输入传染病应作为今后重点防制的主要传染病.%Objective To analyze the epidemic trend of notifiable communicable diseases in Xishuangbanna from 2004 to 2011 and provide evidence for the prevention and control measure development. Methods Descriptive epidemiological analysis was conducted on the incidence data of notifiable communicable diseases in Xishuangbanna during this period, which were collected from national disease reporting information system. Results From 2004 to 2011. No communicable disease case in class A was reported, but 30 511 cases of 18 communicable diseases in class B were reported, including 324 deaths. The average annual incidence was 365. 62/lakh and the average annual death rate was 3. 81/lakh. The first 5 communicable diseases with high incidences in class B were viral hepatitis, pulmonary tuberculosis, typhoid and paratyphoid fevers, malaria and dysentery with the cases accounting for 83. 57% of the total communicable disease cases. Imported dengue fever occurred in 2005, the first rabies case occurred in 2008 and indigenous dengue fever occurred in 2010. Conclusion The

  6. Epidemics and Frequent Recombination within Species in Outbreaks of Human Enterovirus B-Associated Hand, Foot and Mouth Disease in Shandong China in 2010 and 2011.

    Directory of Open Access Journals (Sweden)

    Ting Zhang

    Full Text Available The epidemiology and molecular characteristics of human enterovirus B (HEV-B associated with hand, foot and mouth disease (HFMD outbreaks in China are not well known. In the present study, we tested 201 HEV isolates from 233 clinical specimens from patients with severe HFMD during 2010-2011 in Linyi, Shandong, China. Of the 201 isolates, 189 were fully typed and 18 corresponded to HEV-B species (six serotypes CVA9, CVB1, CVB4, Echo 6, Echo 25 and Echo 30 using sensitive semi-nested polymerase chain reaction analysis of VP1 gene sequences. Phylogenetic analysis based on the VP1 region showed that eight E30SD belonged to a novel sub-genogroup D2; E25SD belonged to a novel sub-genogroup D6; E6SD belonged to sub-lineage C6 and five CVB1SD belonged to subgroup 4C; and B4SD belonged sub-lineage D2. The full viral genomes of the CVB1SD, E6SD, E25SD and E30SD isolates were sequenced. Analysis of phylogenetic and similarity plots indicated that E25SD recombined with E25-HN-2, E30FDJS03 and E4AUS250 at noncontiguous P2A-P3D regions, while E30SD, E30FDJ03, E25-HN-2 and E9 DM had shared sequences in discrete regions of P2 and P3. Both E6SD and B1SD shared sequences with E1-HN, B4/GX/10, B5-HN, and A9-Alberta in contiguous regions of most of P2 and P3. Genetic algorithm recombination detection analysis further confirmed the existence of multiple potential recombination points. In conclusion, analysis of the complete genomes of E25SD, E30SD, CVB1SD and E6SD isolated from HFMD patients revealed that they formed novel subgenogroup. Given the prevalence and recombination of these viruses in outbreaks of HFMD, persistent surveillance of HFMD-associated HEV-B pathogens is required to predict potential emerging viruses and related disease outbreaks.

  7. 尼帕病的流行与防控技术研究现状%Epidemic Status and Prevention Technology of Nipah Disease

    Institute of Scientific and Technical Information of China (English)

    赵永刚; 樊晓旭; 刘学东; 赵明; 吴晓东; 王志亮

    2016-01-01

    The first outbreak of Nipah disease was found in Malaysia. It was not only a serious harm to the pig industry, but also a serious impact on human health. There were numerous reports of Nipah disease outbreaks in Bangladesh and India every year. Phylogenetic analysis of viral N gene sequences revealed that the evolution of the virus was divided into two developmental directions. The effective anti Nipah virus drugs and vaccines havet not been developed yet. Chi-na has initially established detective methods of Nipah virus such as real-time quantitative RT-PCR and indirect ELISA. Although China is free of Nipah,the risk of introduction is not negligible. It is suggested that Nipah should be brought into the scope of comprehensive prevention and control management.%尼帕病首次暴发于东南亚地区的马来西亚,不但严重危害养猪业,而且严重影响着人类的健康。目前,孟加拉国、印度每年都有尼帕病暴发的报道。通过病毒N基因序列的系统进化分析发现,尼帕病毒进化分为两个发展方向。目前还没有研制出有效的抗尼帕病毒药物、疫苗。我国已经初步建立了实时定量RT-PCR和间接ELISA检测尼帕病毒的方法,虽然还没有发现该病的报道,但存在传入的风险。提议我国应将尼帕病纳入综合防控管理范围,积极开展尼帕病防控的宣传与培训,加强尼帕病的技术研究和监测,并制订相关的应急预案。

  8. Epidemic spreading by objective traveling

    Science.gov (United States)

    Tang, Ming; Liu, Zonghua; Li, Baowen

    2009-07-01

    A fundamental feature of agent traveling in social networks is that traveling is usually not a random walk but with a specific destination and goes through the shortest path from starting to destination. A serious consequence of the objective traveling is that it may result in a fast epidemic spreading, such as SARS etc. In this letter we present a reaction-traveling model to study how the objective traveling influences the epidemic spreading. We consider a random scale-free meta-population network with sub-population at each node. Through a SIS model we theoretically prove that near the threshold of epidemic outbreak, the objective traveling can significantly enhance the final infected population and the infected fraction at a node is proportional to its betweenness for the traveling agents and approximately proportional to its degree for the non-traveling agents. Numerical simulations have confirmed the theoretical predictions.

  9. Nepalese origin of cholera epidemic in Haiti.

    Science.gov (United States)

    Frerichs, R R; Keim, P S; Barrais, R; Piarroux, R

    2012-06-01

    Cholera appeared in Haiti in October 2010 for the first time in recorded history. The causative agent was quickly identified by the Haitian National Public Health Laboratory and the United States Centers for Disease Control and Prevention as Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Since then, >500 000 government-acknowledged cholera cases and >7000 deaths have occurred, the largest cholera epidemic in the world, with the real death toll probably much higher. Questions of origin have been widely debated with some attributing the onset of the epidemic to climatic factors and others to human transmission. None of the evidence on origin supports climatic factors. Instead, recent epidemiological and molecular-genetic evidence point to the United Nations peacekeeping troops from Nepal as the source of cholera to Haiti, following their troop rotation in early October 2010. Such findings have important policy implications for shaping future international relief efforts. © 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

  10. Colliding Epidemics and the Rise of Cryptococcosis

    Directory of Open Access Journals (Sweden)

    Christina C. Chang

    2015-12-01

    Full Text Available Discovered more than 100 years ago as a human pathogen, the Cryptococcus neoformans–Cryptococcus gattii (C. neoformans–C. gattii complex has seen a large global resurgence in its association with clinical disease in the last 30 years. First isolated in fermenting peach juice, and identified as a human pathogen in 1894 in a patient with bone lesions, this environmental pathogen has now found niches in soil, trees, birds, and domestic pets. Cryptococcosis is well recognized as an opportunistic infection and was first noted to be associated with reticuloendothelial cancers in the 1950s. Since then, advances in transplant immunology, medical science and surgical techniques have led to increasing numbers of solid organ transplantations (SOT and hematological stem cell transplantations being performed, and the use of biological immunotherapeutics in increasingly high-risk and older individuals, have contributed to the further rise in cryptococcosis. Globally, however, the major driver for revivification of cryptococcosis is undoubtedly the HIV epidemic, particularly in Sub-Saharan Africa where access to care and antiretroviral therapy remains limited and advanced immunodeficiency, poverty and malnutrition remains the norm. As a zoonotic disease, environmental outbreaks of both human and animal cryptococcosis have been reported, possibly driven by climate change. This is best exemplified by the resurgence of C. gattii infection in Vancouver Island, Canada, and the Pacific Northwest of the United States since 1999. Here we describe how the colliding epidemics of HIV, transplantation and immunologics, climate change and migration have contributed to the rise of cryptococcosis.

  11. Association of Drought with Typhus Epidemics in Central Mexico

    Science.gov (United States)

    Acuna-Soto, R.; Stahle, D.; Villanueva Diaz, J.; Therrell, M.

    2007-05-01

    Typhus is an acute infectious disease caused by the bacteria Rickettsia prowazekii, which is transmitted among humans by the body lice (Pediculus humanus corporis). The disease is highly contagious and transmission is favored in populations living in crowded conditions. Under these circumstances, typhus transmission is facilitated by factors that favor the colonization and proliferation of body lice such as absence of personal hygiene and wearing the same clothes for long periods of time. Historically, periods of war and famine were associated with devastating epidemics with high mortality rates in many parts of the world. Central Mexico has a long record of typhus epidemics. In this region, at > 2000 meters above sea level, the disease was endemic and occurred with a seasonal pattern in winter, with occasional large epidemics. Recently, we completed a chronology of epidemics in Mexico. A total of 22 well-defined major typhus epidemics were identified between 1650 and 1920. All of them caused periods of increased mortality that lasted 2 - 4 years (more than one standard deviation from the previous ten year period). The record of typhus epidemics was evaluated against the tree-ring record of Cuauhtmoc La Fragua, Puebla. This chronology, based on Douglas fir, has demonstrated to be a faithful record of precipitation in central Mexico. The results indicate that a statistically significant drought (t test, p < .05) prevailed during the first year of all 22 large outbreaks of typhus in recent Mexican history. No distinction is made between times of peace and war. This indicates that drought alone was capable of inducing the social conditions for increased transmission of typhus in pre-industrial central Mexico.

  12. The narcissism epidemic is dead : Long live the narcissism epidemic

    NARCIS (Netherlands)

    Wetzel, Eunike; Brown, Anna; Hill, Patrick; Chung, J.M.H.; Robins, R.W.; Roberts, B.W.

    2017-01-01

    Are recent cohorts of college students more narcissistic than their predecessors? To address debates about the so-called “narcissism epidemic,” we used data from three cohorts of students (N1990s = 1,166; N2000s = 33,647; N2010s = 25,412) to test whether narcissism levels (overall and specific

  13. The narcissism epidemic is dead : Long live the narcissism epidemic

    NARCIS (Netherlands)

    Wetzel, Eunike; Brown, Anna; Hill, Patrick; Chung, J.M.H.; Robins, R.W.; Roberts, B.W.

    2017-01-01

    Are recent cohorts of college students more narcissistic than their predecessors? To address debates about the so-called “narcissism epidemic,” we used data from three cohorts of students (N1990s = 1,166; N2000s = 33,647; N2010s = 25,412) to test whether narcissism levels (overall and specific facet

  14. Chikungunya, an epidemic arbovirosis.

    Science.gov (United States)

    Pialoux, Gilles; Gaüzère, Bernard-Alex; Jauréguiberry, Stéphane; Strobel, Michel

    2007-05-01

    Chikungunya is an arboviral disease transmitted by aedes mosquitoes. The virus was first isolated in 1953 in Tanzania. Chikungunya virus is a member of the genus Alphavirus and the family Togaviridae. The disease typically consists of an acute illness characterised by fever, rash, and incapacitating arthralgia. The word chikungunya, used for both the virus and the disease, means "to walk bent over" in some east African languages, and refers to the effect of the joint pains that characterise this dengue-like infection. Chikungunya is a specifically tropical disease, but it is geographically restricted and outbreaks are relatively uncommon. It is only occasionally observed in travellers and military personnel. More than 266 000 people have been infected during the ongoing outbreak in Réunion, in which Aedes albopictus is the presumed vector. In the ongoing Indian outbreak, in which Aedes aegypti is the presumed vector, 1 400 000 cases of chikungunya were reported during 2006. The reasons for the re-emergence of chikungunya on the Indian subcontinent, and for its unprecedented incidence rate in the Indian Ocean region, are unclear. Plausible explanations include increased tourism, chikungunya virus introduction into a naive population, and viral mutation.

  15. Optimal control of a dengue epidemic model with vaccination

    CERN Document Server

    Rodrigues, Helena Sofia; Torres, Delfim F M

    2011-01-01

    We present a SIR+ASI epidemic model to describe the interaction between human and dengue fever mosquito populations. A control strategy in the form of vaccination, to decrease the number of infected individuals, is used. An optimal control approach is applied in order to find the best way to fight the disease.

  16. Using clinicians' search query data to monitor influenza epidemics.

    Science.gov (United States)

    Santillana, Mauricio; Nsoesie, Elaine O; Mekaru, Sumiko R; Scales, David; Brownstein, John S

    2014-11-15

    Search query information from a clinician's database, UpToDate, is shown to predict influenza epidemics in the United States in a timely manner. Our results show that digital disease surveillance tools based on experts' databases may be able to provide an alternative, reliable, and stable signal for accurate predictions of influenza outbreaks.

  17. Vaccination Control in a Stochastic SVIR Epidemic Model.

    Science.gov (United States)

    Witbooi, Peter J; Muller, Grant E; Van Schalkwyk, Garth J

    2015-01-01

    For a stochastic differential equation SVIR epidemic model with vaccination, we prove almost sure exponential stability of the disease-free equilibrium for ℛ(0) stochastic model as well as for the underlying deterministic model. In order to solve the stochastic problem numerically, we use an approximation based on the solution of the deterministic model.

  18. Using Clinicians’ Search Query Data to Monitor Influenza Epidemics

    Science.gov (United States)

    Santillana, Mauricio; Nsoesie, Elaine O.; Mekaru, Sumiko R.; Scales, David; Brownstein, John S.

    2014-01-01

    Search query information from a clinician's database, UpToDate, is shown to predict influenza epidemics in the United States in a timely manner. Our results show that digital disease surveillance tools based on experts' databases may be able to provide an alternative, reliable, and stable signal for accurate predictions of influenza outbreaks. PMID:25115873

  19. STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper,we study an SIS epidemic model with a time variant delay.By means of Liapunov functional,some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained.The influence of time delay on the stability of equilibria is displayed.

  20. STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY

    Institute of Scientific and Technical Information of China (English)

    YUAN Sanling; MA Zhien

    2002-01-01

    In this paper, we study an SIS epidemic model with a time variant delay.By means of Liapunov functional, some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained. The influence of time delay on the stability of equilibria is displayed.

  1. GLOBAL STABILITY OF AN SIRS EPIDEMIC MODEL WITH DELAYS

    Institute of Scientific and Technical Information of China (English)

    Zhen Jin; Ma Zhien; Han Maoan

    2006-01-01

    In this article, an SIRS epidemic model spread by vectors (mosquitoes) which have an incubation time to become infectious is formulated. It is shown that a disease-free equilibrium point is globally stable if no endemic equilibrium point exists. Further, the endemic equilibrium point (if it exists) is globally stable with a respect "weak delay". Some known results are generalized.

  2. 来宾市2009-2013年乙类传染病流行趋势分析%Analysis of epidemic trend of the category B infectious diseases in Laibin City from 2009 to 2013

    Institute of Scientific and Technical Information of China (English)

    毛伟成; 蓝荣伟; 蒙南新; 虞海芬; 曾柳玉

    2015-01-01

    目的:了解来宾市法定报告乙类传染病流行趋势。方法收集来宾市2009—2013年法定传染病疫情报告资料,应用Excel 2003对数据进行统计处理,采用描述性流行病学方法进行分析,并用Cochran Armitage 趋势检验分析发病率年度变化趋势。结果来宾市2009—2013年累计报告乙类传染病19种45113例,年均报告发病率为410.17/10万,年均死亡率为8.14/10万;发病率呈平稳态势,死亡率呈上升趋势。血源及性传播疾病和呼吸道传染病的发病数分别占总发病数的48.67%和47.08%。呼吸道传染病发病率呈上升趋势,肠道、血源及性传播、自然疫源及虫媒等传染病的发病率则呈下降趋势。发病率居前5位的传染病依次为肺结核、梅毒、乙肝、AIDS/HIV、丙肝;肺结核、AIDS/HIV发病率呈上升趋势,梅毒发病率呈下降趋势。死亡率前4位的传染病依次是AIDS/HIV、狂犬病、肺结核、乙肝;AIDS/HIV死亡率呈上升趋势,狂犬病、肺结核死亡率呈下降趋势。结论2009—2013年来宾市乙类传染病防控取得了较好成效,当前威胁该市的乙类传染病主要是肺结核、梅毒、肝炎、AIDS/HIV、狂犬病等。%Objective To understand the epidemic trend of category B infectious diseases in Laibin City. Methods The epidemic data of category B infectious diseases in Laibin City from 2009 to 2013 were collected and analyzed with descriptive epidemiological method. The trend of the morbidity and mortality were analyzed with Cochran Armitage trend test. Results A total of 45 113 cases belonging to 19 kinds of the category B infectious diseases were reported during the period in Laibin City. The average annual incidence rate and mortality rate of the diseases were 410.17/100 000 and 8.14/100 000 ,respectively .From 2009 to 2013 the annual incidence rates had no great changes but the annual mortality rates increased. The major proportions of the reported

  3. Visual Mining of Epidemic Networks

    CERN Document Server

    Clémençon, Stéphan; Rossi, Fabrice; Tran, Viet Chi; 10.1007/978-3-642-21498-1_35

    2012-01-01

    We show how an interactive graph visualization method based on maximal modularity clustering can be used to explore a large epidemic network. The visual representation is used to display statistical tests results that expose the relations between the propagation of HIV in a sexual contact network and the sexual orientation of the patients.

  4. Epidemic Spread in Human Networks

    CERN Document Server

    Sahneh, Faryad Darabi

    2011-01-01

    One of the popular dynamics on complex networks is the epidemic spreading. An epidemic model describes how infections spread throughout a network. Among the compartmental models used to describe epidemics, the Susceptible-Infected-Susceptible (SIS) model has been widely used. In the SIS model, each node can be susceptible, become infected with a given infection rate, and become again susceptible with a given curing rate. In this paper, we add a new compartment to the classic SIS model to account for human response to epidemic spread. Each individual can be infected, susceptible, or alert. Susceptible individuals can become alert with an alerting rate if infected individuals exist in their neighborhood. An individual in the alert state is less probable to become infected than an individual in the susceptible state; due to a newly adopted cautious behavior. The problem is formulated as a continuous-time Markov process on a general static graph and then modeled into a set of ordinary differential equations using...

  5. Epidemic Synchronization in Robotic Swarms

    DEFF Research Database (Denmark)

    Schiøler, Henrik; Nielsen, Jens Frederik Dalsgaard; Ngo, Trung Dung

    2009-01-01

    Clock synchronization in swarms of networked mobile robots is studied in a probabilistic, epidemic framework. In this setting communication and synchonization is considered to be a randomized process, taking place at unplanned instants of geographical rendezvous between robots. In combination wit...

  6. Steady States in SIRS Epidemical Model of Mobile Individuals

    Institute of Scientific and Technical Information of China (English)

    ZHANG Duan-Ming; LIU Dan; HE Min-Hua; YU Xiao-Ling; PAN Gui-Jun; SUN Hong-Zhang; SU Xiang-Ying; SUN Fan; YIN Yan-Ping; LI Rui

    2006-01-01

    We consider an epidemical model within socially interacting mobile individuals to study the behaviors of steady statesof epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations, we recover the usual epidemic behavior with critical thresholds δc and pc below which infectious disease dies out. For the population density δ far above δc, it is found that there is linear relationship between contact rate λ and the population density δ in the main. At the same time, the result obtained from mean-field approximation is compared with our numerical result, and it is found that these two results are similar by and large but not completely the same.

  7. Steady States in SIRS Epidemical Model of Mobile Individuals

    Science.gov (United States)

    Zhang, Duan-Ming; He, Min-Hua; Yu, Xiao-Ling; Pan, Gui-Jun; Sun, Hong-Zhang; Su, Xiang-Ying; Sun, Fan; Yin, Yan-Ping; Li, Rui; Liu, Dan

    2006-01-01

    We consider an epidemical model within socially interacting mobile individuals to study the behaviors of steady states of epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations, we recover the usual epidemic behavior with critical thresholds δc and pc below which infectious disease dies out. For the population density δ far above δc, it is found that there is linear relationship between contact rate λ and the population density δ in the main. At the same time, the result obtained from mean-field approximation is compared with our numerical result, and it is found that these two results are similar by and large but not completely the same.

  8. Competing spreading processes on multiplex networks: awareness and epidemics

    CERN Document Server

    Granell, Clara; Arenas, Alex

    2014-01-01

    Epidemic-like spreading processes on top of multilayered interconnected complex networks reveal a rich phase diagram of intertwined competition effects. A recent study by the authors [Granell et al. Phys. Rev. Lett. 111, 128701 (2013)] presented the analysis of the interrelation between two processes accounting for the spreading of an epidemics, and the spreading of information awareness to prevent its infection, on top of multiplex networks. The results in the case in which awareness implies total immunization to the disease, revealed the existence of a metacritical point at which the critical onset of the epidemics starts depending on the reaching of the awareness process. Here we present a full analysis of these critical properties in the more general scenario where the awareness spreading does not imply total immunization, and where infection does not imply immediate awareness of it. We find the critical relation between both competing processes for a wide spectrum of parameters representing the interacti...

  9. Efficient mitigation strategies for epidemics in rural regions

    CERN Document Server

    Scoglio, Caterina; Schumm, Phillip; Easton, Todd; Chowdhury, Sohini Roy; Sydney, Ali; Youssef, Mina

    2010-01-01

    Containing an epidemic at its origin is the most desirable mitigation. Epidemics have often originated in rural areas, with rural communities among the first affected. Disease dynamics in rural regions have received limited attention, and results of general studies cannot be directly applied since population densities and human mobility factors are very different in rural regions from those in cities. We create a network model of a rural community in Kansas, USA, by collecting data on the contact patterns and computing rates of contact among a sampled population. We model the impact of different mitigation strategies detecting closely connected groups of people and frequently visited locations. Within those groups and locations, we compare the effectiveness of random and targeted vaccinations using a Susceptible-Exposed-Infected-Recovered compartmental model on the contact network. Our simulations show that the targeted vaccinations of only 10% of the sampled population reduced the size of the epidemic by 34....

  10. Temporal Dynamics of Connectivity and Epidemic Properties of Growing Networks

    CERN Document Server

    Fotouhi, Babak

    2015-01-01

    Traditional mathematical models of epidemic disease had for decades conventionally considered static structure for contacts. Recently, an upsurge of theoretical inquiry has strived towards rendering the models more realistic by incorporating the temporal aspects of networks of contacts, societal and online, that are of interest in the study of epidemics (and other similar diffusion processes). However, temporal dynamics have predominantly focused on link fluctuations and nodal activities, and less attention has been paid to the growth of the underlying network. Many real networks grow: online networks are evidently in constant growth, and societal networks can grow due to migration flux and reproduction. The effect of network growth on the epidemic properties of networks is hitherto unknown---mainly due to the predominant focus of the network growth literature on the so-called steady-state. This paper takes a step towards alleviating this gap. We analytically study the degree dynamics of a given arbitrary net...

  11. Effects of Weak Ties on Epidemic Predictability in Community Networks

    CERN Document Server

    Shu, Panpan; Gong, Kai; Liu, Ying

    2012-01-01

    Weak ties play a significant role in the structures and the dynamics of community networks. Based on the susceptible-infected model in contact process, we study numerically how weak ties influence the predictability of epidemic dynamics. We first investigate the effects of different kinds of weak ties on the variabilities of both the arrival time and the prevalence of disease, and find that the bridgeness with small degree can enhance the predictability of epidemic spreading. Once weak ties are settled, compared with the variability of arrival time, the variability of prevalence displays a diametrically opposed changing trend with both the distance of the initial seed to the bridgeness and the degree of the initial seed. More specifically, the further distance and the larger degree of the initial seed can induce the better predictability of arrival time and the worse predictability of prevalence. Moreover, we discuss the effects of weak tie number on the epidemic variability. As community strength becomes ver...

  12. Spatial extent of an outbreak in animal epidemics.

    Science.gov (United States)

    Dumonteil, Eric; Majumdar, Satya N; Rosso, Alberto; Zoia, Andrea

    2013-03-12

    Characterizing the spatial extent of epidemics at the outbreak stage is key to controlling the evolution of the disease. At the outbreak, the number of infected individuals is typically small, and therefore, fluctuations around their average are important: then, it is commonly assumed that the susceptible-infected-recovered mechanism can be described by a stochastic birth-death process of Galton-Watson type. The displacements of the infected individuals can be modeled by resorting to brownian motion, which is applicable when long-range movements and complex network interactions can be safely neglected, like in the case of animal epidemics. In this context, the spatial extent of an epidemic can be assessed by computing the convex hull enclosing the infected individuals at a given time. We derive the exact evolution equations for the mean perimeter and the mean area of the convex hull, and we compare them with Monte Carlo simulations.

  13. Epidemic spread over networks with agent awareness and social distancing

    KAUST Repository

    Paarporn, Keith

    2016-04-20

    We study an SIS epidemic model over an arbitrary connected network topology when the agents receive personalized information about the current epidemic state. The agents utilize their available information to either reduce interactions with their neighbors (social distancing) when they believe the epidemic is currently prevalent or resume normal interactions when they believe there is low risk of becoming infected. The information is a weighted combination of three sources: 1) the average states of nodes in contact neighborhoods 2) the average states of nodes in an information network 3) a global broadcast of the average epidemic state of the network. A 2n-state Markov Chain is first considered to model the disease dynamics with awareness, from which a mean-field discrete-time n-state dynamical system is derived, where each state corresponds to an agent\\'s probability of being infected. The nonlinear model is a lower bound of its linearized version about the origin. Hence, global stability of the origin (the diseasefree equilibrium) in the linear model implies global stability in the nonlinear model. When the origin is not stable, we show the existence of a nontrivial fixed point in the awareness model, which obeys a strict partial order in relation to the nontrivial fixed point of the dynamics without distancing. In simulations, we define two performance metrics to understand the effectiveness agent awareness has in reducing the spread of an epidemic. © 2015 IEEE.

  14. SIS model of epidemic spreading on dynamical networks with community

    Institute of Scientific and Technical Information of China (English)

    Chengyi XIA; Shiwen SUN; Feng RAO; Junqing SUN; Jinsong WANG; Zengqiang CHEN

    2009-01-01

    We present a new epidemic Susceptible-Infected-Susceptible (SIS) model to investigate the spreading behav-ior on networks with dynamical topology and community structure. Individuals in the model are mobile agents who are allowed to perform the inter-community (i.e., long-range) motion with the probability p. The mean-field theory is uti-lized to derive the critical threshold (λ_C) of epidemic spread-ing inside separate communities and the influence of the long-range motion on the epidemic spreading. The results indicate that λ_C is only related with the population density within the community, and the long-range motion will make the original disease-free community become the endemic state. Large-scale numerical simulations also demonstrate the theoretical approximations based on our new epidemic model. The current model and analysis will help us to fur-ther understand the propagation behavior of real epidemics taking place on social networks.

  15. [Observations on the 1348 plague epidemic. Measures taken to combat its tragic effects and avoid epidemic recrudescence].

    Science.gov (United States)

    Sabbatani, Sergio

    2003-03-01

    When the "Black Death" swept through Europe from southern France in 1348, in the short space of two years the Europeans were hit by one of the most serious epidemics ever recorded in human history. Yersinia pestis reached Europe by sea, its contamination propagated by the Genoese ships coming from the Crimean port of Jaffa. For the first time the world experienced microbiological unification: East and West were equally involved in the tragedy that spread, and no town remained unscathed during the various epidemic waves which succeeded one another in the following three centuries. The authors of this article describe how and why the epidemic spread, as well as the factors that led to the swift, and often fatal, involment of millions of Europeans. The second part of the article deals with the measures taken by the healthcare authorities of European towns and countries in order to halt the proliferation of the disease. According to the data and observations by authoritative authors, selected among the many who studied the disease that from the 14th century spread like a scourge throughout the known world at the time, the epidemic could have been even more serious, in terms of mortality and morbidity, without the disciplinary and provisional health measures taken. The experience gained in Italy and all over Europe at the time proved useful not only to better manage the epidemics which cyclically broke out, but also to efficiently combat the cholera epidemics of the 19th century. With the 14th century plague epidemic, the Europeans and their political and administrative representatives may well have realized for the very first time that contamination could be combatted by adopting a set of rational, scientific norms - although in practice such rules were mostly inspired by misguided scientific theories. Humankind was no longer alone. A new society was emerging, one that was not going to passively accept the more or less mysterious ways of a superior being of fate. The

  16. Epidemics spreading in interconnected complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Institute of High Performance Computing, Agency for Science, Technology and Research (A-STAR), Singapore 138632 (Singapore); Xiao, G., E-mail: egxxiao@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2012-09-03

    We study epidemic spreading in two interconnected complex networks. It is found that in our model the epidemic threshold of the interconnected network is always lower than that in any of the two component networks. Detailed theoretical analysis is proposed which allows quick and accurate calculations of epidemic threshold and average outbreak/epidemic size. Theoretical analysis and simulation results show that, generally speaking, the epidemic size is not significantly affected by the inter-network correlation. In interdependent networks which can be viewed as a special case of interconnected networks, however, impacts of inter-network correlation on the epidemic threshold and outbreak size are more significant. -- Highlights: ► We study epidemic spreading in two interconnected complex networks. ► The epidemic threshold is lower than that in any of the two networks. And Interconnection correlation has impacts on threshold and average outbreak size. ► Detailed theoretical analysis is proposed which allows quick and accurate calculations of epidemic threshold and average outbreak/epidemic size. ► We demonstrated and proved that Interconnection correlation does not affect epidemic size significantly. ► In interdependent networks, impacts of inter-network correlation on the epidemic threshold and outbreak size are more significant.

  17. The emerging epidemic of hypertension in Asian children and adolescents.

    Science.gov (United States)

    Lee, Chong Guk

    2014-12-01

    Hypertension has become a serious global public health burden because of its high incidence and concomitant risk of cardiovascular disease. Many studies have verified that risk factors, such as hypertension and obesity which are responsible for cardiovascular disease, start in early childhood. In Asian countries, the prevalence of hypertension in the pediatric age group has become more prevalent than ever before with the increasing obesity epidemic. To tackle the epidemic of cardiovascular disease, a leading cause of death and disability of non-communicable diseases in Asian countries, population-based measures aiming at reducing harmful environmental factors to blood pressure and body weight must be applied to individuals in their early childhood, as early as the fetal stage. This review focused on the prevalence of pediatric hypertension in Asian countries and outlined several considerations for accurate blood pressure (BP) measurement and evaluation, along with an overview of pathophysiology of fetal programming and obesity related with childhood hypertension.

  18. CHEMICAL VERSUS SERUM TREATMENT OF EPIDEMIC MENINGITIS.

    Science.gov (United States)

    Flexner, S; Amoss, H L

    1916-05-01

    of meningococci, and neither possesses antitoxic power. The mixture of antiserum with lysol and with protargol reduces to a certain extent the antileukotactic and antiphagocytic effect of the chemicals; but this action is insufficient to set aside wholly the injurious effects which they produce. It follows, therefore, that whatever theoretical advantages might accrue from a bactericidal activity exerted by these chemicals independently of the type of meningococcus causing epidemic meningitis, is more than offset by the harmful effects which they cause. Hence specific antiserum seems to provide the logical therapeutic agent with which to combat epidemic meningitis, since it is itself innocuous and promotes those processes essential to recovery from the disease. The problem up to the present has been that of producing an antiserum which represents the several types of the meningococcus, and this problem is now in a fair way to being solved.

  19. Spatiotemporal dynamics of the epidemic transmission in a predator-prey system.

    Science.gov (United States)

    Su, Min; Hui, Cang; Zhang, Yanyu; Li, Zizhen

    2008-11-01

    Epidemic transmission is one of the critical density-dependent mechanisms that affect species viability and dynamics. In a predator-prey system, epidemic transmission can strongly affect the success probability of hunting, especially for social animals. Predators, therefore, will suffer from the positive density-dependence, i.e., Allee effect, due to epidemic transmission in the population. The rate of species contacting the epidemic, especially for those endangered or invasive, has largely increased due to the habitat destruction caused by anthropogenic disturbance. Using ordinary differential equations and cellular automata, we here explored the epidemic transmission in a predator-prey system. Results show that a moderate Allee effect will destabilize the dynamics, but it is not true for the extreme Allee effect (weak or strong). The predator-prey dynamics amazingly stabilize by the extreme Allee effect. Predators suffer the most from the epidemic disease at moderate transmission probability. Counter-intuitively, habitat destruction will benefit the control of the epidemic disease. The demographic stochasticity dramatically influences the spatial distribution of the system. The spatial distribution changes from oil-bubble-like (due to local interaction) to aggregated spatially scattered points (due to local interaction and demographic stochasticity). It indicates the possibility of using human disturbance in habitat as a potential epidemic-control method in conservation.

  20. The initial hospital response to an epidemic.

    Science.gov (United States)

    Petrosillo, Nicola; Puro, Vincenzo; Di Caro, Antonino; Ippolito, Giuseppe

    2005-01-01

    The last decades have been characterized by the appearance of a substantial number of newly recognized or novel infectious agents and by the re-emergence of infectious diseases with a global impact. The objective of this article is to briefly describe the model of hospital response for early diagnosis and prompt management of patients with highly contagious infectious diseases. We reviewed the main components of hospital preparedness in response to clustering of highly contagious diseases. A model for the initial hospital response to an epidemic in our referral Institute is discussed. Prompt recognition and identification is the initial and indispensable step in facing any communicable diseases, regardless of whether it is a prevalent, a newly emerging one or deliberately released. The importance of developing and implementing nontraditional methods of public health surveillance and a system that allows a wide and immediate dissemination of information and exchange of views on risk assessment and risk management are highlighted. Case identification and laboratory capabilities and isolation procedures are the essential components for an initial hospital response. The recent bioterrorist events and the worldwide outbreaks of highly contagious infectious diseases have evidenced the need for institutional preparedness at each hospital and for identification of referral centers for patient isolation and of laboratories with adequate capabilities. Moreover, hospitals should develop a plan for coordinating all hospital components to respond to critical situations deriving from the admission of patients with highly contagious infectious diseases.

  1. A Theory on the Ventilation over Hypothetical Urban Areas

    Science.gov (United States)

    Liu, Chun-Ho; Ng, Chi-To; Wong, Colman C. C.

    2013-04-01

    Urban roughness is one of the major factors affecting the flows and turbulence structures in the bottom of the atmospheric boundary layer (ABL). Whereas, our understanding of their relation is limited. In this paper, we attempt to examine the interaction among aerodynamic resistance (friction factor f), ventilation (air exchange rate ACH), and pollutant removal (pollutant removal rate PCH). Using the method of characteristic, analytical solution shows that the turbulent ventilation of a hypothetical urban area is directly proportional to the square root of friction factor (ACH? f1-2) regardless of the building geometry. Next, a series of computational fluid dynamics (CFD) sensitivity tests are performed to verify the theory. In addition to the commonly employed rectangular building models, seven types of urban roughness elements, in the form of idealized building models, are tested. As a pilot study, the building models are of the same height so a roof level is easily defined across the entire hypothetical urban areas. Two configurations of passive scalar sources, ground-level-only (vehicular emission) and all-solid-boundary (heat dissipation), are employed to contrast their transport behaviors. To look into the mechanism of ventilation and pollutant removal, the ACH and PCH are partitioned into their respective mean and turbulent components. The CFD results show that both the ventilation and pollutant removal are mainly attributed to their turbulent components (over 60%). Moreover, the ACH″ and f1-2 calculation from the CFD results agree very well with the analytical solution (correlation coefficient over 0.9). However, the pollutant and heat exhibit different removal behaviors so simple estimates using friction factor have not yet arrived. Because of the substantial aged air removal by ACH″ and its linear relation with f1-2, it is proposed to use friction factor, which can be determined by wind tunnel experiments or mathematical modeling, as a

  2. Radiological Consequence Analyses Following a Hypothetical Severe Accident in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Juyub; Kim, Juyoul [FNC Technology Co., Yongin (Korea, Republic of)

    2016-10-15

    In order to reflect the lessons learned from the Fukushima Daiichi nuclear power plant accident, a simulator which is named NANAS (Northeast Asia Nuclear Accident Simulator) for overseas nuclear accident has been developed. It is composed of three modules: source-term estimation, atmospheric dispersion prediction and dose assessment. For the source-term estimation module, the representative reactor types were selected as CPR1000, BWR5 and BWR6 for China, Japan and Taiwan, respectively. Considering the design characteristics of each reactor type, the source-term estimation module simulates the transient of design basis accident and severe accident. The atmospheric dispersion prediction module analyzes the transport and dispersion of radioactive materials and prints out the air and ground concentration. Using the concentration result, the dose assessment module calculates effective dose and thyroid dose in the Korean Peninsula region. In this study, a hypothetical severe accident in Japan was simulated to demonstrate the function of NANAS. As a result, the radiological consequence to Korea was estimated from the accident. PC-based nuclear accident simulator, NANAS, has been developed. NANAS contains three modules: source-term estimation, atmospheric dispersion prediction and dose assessment. The source-term estimation module simulates a nuclear accident for the representative reactor types in China, Japan and Taiwan. Since the maximum calculation speed is 16 times than real time, it is possible to estimate the source-term release swiftly in case of the emergency. The atmospheric dispersion prediction module analyzes the transport and dispersion of radioactive materials in wide range including the Northeast Asia. Final results of the dose assessment module are a map projection and time chart of effective dose and thyroid dose. A hypothetical accident in Japan was simulated by NANAS. The radioactive materials were released during the first 24 hours and the source

  3. SIS epidemics on Triadic Random Graphs

    CERN Document Server

    Rausch, Ilja

    2016-01-01

    It has been shown in the past that many real-world networks exhibit community structures and non-trivial clustering which comes with the occurrence of a notable number of triangular connections. Yet the influence of such connection patterns on the dynamics of disease transmission is not fully understood. In order to study their role in the context of Susceptible-Infected-Susceptible (SIS) epidemics we use the Triadic Random Graph (TRG) model to construct small networks (N=49) from distinct, closed, directed triadic subpatterns. We compare various global properties of TRGs and use the N-intertwined mean-field approximation (NIMFA) model to perform numerical simulations of SIS-dynamics on TRGs. The results show that the infection spread on undirected TRGs displays very similar behavior to TRGs with an abundance of (directed) feed-back-loops, while using (directed) feed-forward-loops as network-entities significantly slows down the epidemic and lowers the number of infected individuals in the endemic state. More...

  4. Modelling dengue epidemic spreading with human mobility

    Science.gov (United States)

    Barmak, D. H.; Dorso, C. O.; Otero, M.

    2016-04-01

    We explored the effect of human mobility on the spatio-temporal dynamics of Dengue with a stochastic model that takes into account the epidemiological dynamics of the infected mosquitoes and humans, with different mobility patterns of the human population. We observed that human mobility strongly affects the spread of infection by increasing the final size and by changing the morphology of the epidemic outbreaks. When the spreading of the disease is driven only by mosquito dispersal (flight), a main central focus expands diffusively. On the contrary, when human mobility is taken into account, multiple foci appear throughout the evolution of the outbreaks. These secondary foci generated throughout the outbreaks could be of little importance according to their mass or size compared with the largest main focus. However, the coalescence of these foci with the main one generates an effect, through which the latter develops a size greater than the one obtained in the case driven only by mosquito dispersal. This increase in growth rate due to human mobility and the coalescence of the foci are particularly relevant in temperate cities such as the city of Buenos Aires, since they give more possibilities to the outbreak to grow before the arrival of the low-temperature season. The findings of this work indicate that human mobility could be the main driving force in the dynamics of vector epidemics.

  5. Impact of spatially constrained sampling of temporal contact networks on the evaluation of the epidemic risk

    CERN Document Server

    Vestergaard, Christian L; Génois, Mathieu; Poletto, Chiara; Colizza, Vittoria; Barrat, Alain

    2016-01-01

    The ability to directly record human face-to-face interactions increasingly enables the development of detailed data-driven models for the spread of directly transmitted infectious diseases at the scale of individuals. Complete coverage of the contacts occurring in a population is however generally unattainable, due for instance to limited participation rates or experimental constraints in spatial coverage. Here, we study the impact of spatially constrained sampling on our ability to estimate the epidemic risk in a population using such detailed data-driven models. The epidemic risk is quantified by the epidemic threshold of the susceptible-infectious-recovered-susceptible model for the propagation of communicable diseases, i.e. the critical value of disease transmissibility above which the disease turns endemic. We verify for both synthetic and empirical data of human interactions that the use of incomplete data sets due to spatial sampling leads to the underestimation of the epidemic risk. The bias is howev...

  6. Lessons learned during public health response to cholera epidemic in Haiti and the Dominican Republic

    National Research Council Canada - National Science Library

    Tappero, Jordan W; Tauxe, Robert V

    2011-01-01

    After epidemic cholera emerged in Haiti in October 2010, the disease spread rapidly in a country devastated by an earthquake earlier that year, in a population with a high proportion of infant deaths...

  7. Analysis of a novel stochastic SIRS epidemic model with two different saturated incidence rates

    Science.gov (United States)

    Chang, Zhengbo; Meng, Xinzhu; Lu, Xiao

    2017-04-01

    This paper presents a stochastic SIRS epidemic model with two different nonlinear incidence rates and double epidemic asymmetrical hypothesis, and we devote to develop a mathematical method to obtain the threshold of the stochastic epidemic model. We firstly investigate the boundness and extinction of the stochastic system. Furthermore, we use Ito's formula, the comparison theorem and some new inequalities techniques of stochastic differential systems to discuss persistence in mean of two diseases on three cases. The results indicate that stochastic fluctuations can suppress the disease outbreak. Finally, numerical simulations about different noise disturbance coefficients are carried out to illustrate the obtained theoretical results.

  8. Forecasting fluctuating outbreaks in seasonally driven epidemics

    Science.gov (United States)

    Stone, Lewi

    2009-03-01

    Seasonality is a driving force that has major impact on the spatio-temporal dynamics of natural systems and their populations. This is especially true for the transmission of common infectious diseases such as influenza, measles, chickenpox, and pertussis. Here we gain new insights into the nonlinear dynamics of recurrent diseases through the analysis of the classical seasonally forced SIR epidemic model. Despite many efforts over the last decades, it has been difficult to gain general analytical insights because of the complex synchronization effects that can evolve between the external forcing and the model's natural oscillations. The analysis advanced here attempts to make progress in this direction by focusing on the dynamics of ``skips'' where we identify and predict years in which the epidemic is absent rather than outbreak years. Skipping events are intrinsic to the forced SIR model when parameterised in the chaotic regime. In fact, it is difficult if not impossible to locate realistic chaotic parameter regimes in which outbreaks occur regularly each year. This contrasts with the well known Rossler oscillator whose outbreaks recur regularly but whose amplitude vary chaotically in time (Uniform Phase Chaotic Amplitude oscillations). The goal of the present study is to develop a ``language of skips'' that makes it possible to predict under what conditions the next outbreak is likely to occur, and how many ``skips'' might be expected after any given outbreak. We identify a new threshold effect and give clear analytical conditions that allow accurate predictions. Moreover, the time of occurrence (i.e., phase) of an outbreak proves to be a useful new parameter that carries important epidemiological information. In forced systems, seasonal changes can prevent late-initiating outbreaks (i.e., having high phase) from running to completion. These principles yield forecasting tools that should have relevance for the study of newly emerging and reemerging diseases.

  9. Disability and marginal utility of income: evidence from hypothetical choices.

    Science.gov (United States)

    Tengstam, Sven

    2014-03-01

    It is often assumed that disability reduces the marginal utility of income. In this article, individuals' marginal utility of income in two states-(i) paralyzed in both legs from birth and (ii) not mobility impaired at all-is measured through hypothetical choices between imagined lotteries behind a so-called veil of ignorance. The outcomes of the lotteries include both income and disability status. It is found that most people have higher marginal utility when paralyzed than when not mobility impaired at all. The two marginal utilities are evaluated at the same levels of income. Having personal experience of mobility impairment and supporting the Left Party, the Social Democratic Party, the Green Party, or the Liberal Party are associated with having a higher marginal utility when paralyzed. The results suggest that more than full insurance of income losses connected to being disabled is optimal. The results further suggest that, given a utilitarian social welfare function, resources should be transferred to rather than from disabled people. Finally, if the transfers are not large enough to smooth out the marginal utilities of the disabled and the nondisabled, distributional weights based on disability status should be used in cost-benefit analysis.

  10. Comprehensive computerized medical imaging: interim hypothetical economic evaluation

    Science.gov (United States)

    Warburton, Rebecca N.; Fisher, Paul D.; Nosil, Josip

    1990-08-01

    The 422-bed Victoria General Hospital (VGH) and Siemens Electric Limited have since 1983 been piloting the implementation of comprehensive computerized medical imaging, including digital acquisition of diagnostic images, in British Columbia. Although full PACS is not yet in place at VGH, experience to date habeen used to project annual cost figures (including capital replacement) for a fully-computerized department. The resulting economic evaluation has been labelled hypothetical to emphasize that some key cost components were estimated rather than observed; this paper presents updated cost figures based on recent revisions to proposed departmental equipment configuration which raised the cost of conventional imaging equipment by 0.3 million* and lowered the cost of computerized imaging equipment by 0.8 million. Compared with conventional diagnostic imaging, computerized imaging appears to raise overall annual costs at VGH by nearly 0.7 million, or 11.6%; this is more favourable than the previous results, which indicated extra annual costs of 1 million (16.9%). Sensitivity analysis still indicates that all reasonable changes in the underlying assumptions result in higher costs for computerized imaging than for conventional imaging. Computerized imaging offers lower radiation exposure to patients, shorter waiting times, and other potential advantages, but as yet the price of obtaining these benefits remains substantial.

  11. Large-scale screening of hypothetical metal-organic frameworks

    Science.gov (United States)

    Wilmer, Christopher E.; Leaf, Michael; Lee, Chang Yeon; Farha, Omar K.; Hauser, Brad G.; Hupp, Joseph T.; Snurr, Randall Q.

    2012-02-01

    Metal-organic frameworks (MOFs) are porous materials constructed from modular molecular building blocks, typically metal clusters and organic linkers. These can, in principle, be assembled to form an almost unlimited number of MOFs, yet materials reported to date represent only a tiny fraction of the possible combinations. Here, we demonstrate a computational approach to generate all conceivable MOFs from a given chemical library of building blocks (based on the structures of known MOFs) and rapidly screen them to find the best candidates for a specific application. From a library of 102 building blocks we generated 137,953 hypothetical MOFs and for each one calculated the pore-size distribution, surface area and methane-storage capacity. We identified over 300 MOFs with a predicted methane-storage capacity better than that of any known material, and this approach also revealed structure-property relationships. Methyl-functionalized MOFs were frequently top performers, so we selected one such promising MOF and experimentally confirmed its predicted capacity.

  12. Large-scale screening of hypothetical metal-organic frameworks.

    Science.gov (United States)

    Wilmer, Christopher E; Leaf, Michael; Lee, Chang Yeon; Farha, Omar K; Hauser, Brad G; Hupp, Joseph T; Snurr, Randall Q

    2011-11-06

    Metal-organic frameworks (MOFs) are porous materials constructed from modular molecular building blocks, typically metal clusters and organic linkers. These can, in principle, be assembled to form an almost unlimited number of MOFs, yet materials reported to date represent only a tiny fraction of the possible combinations. Here, we demonstrate a computational approach to generate all conceivable MOFs from a given chemical library of building blocks (based on the structures of known MOFs) and rapidly screen them to find the best candidates for a specific application. From a library of 102 building blocks we generated 137,953 hypothetical MOFs and for each one calculated the pore-size distribution, surface area and methane-storage capacity. We identified over 300 MOFs with a predicted methane-storage capacity better than that of any known material, and this approach also revealed structure-property relationships. Methyl-functionalized MOFs were frequently top performers, so we selected one such promising MOF and experimentally confirmed its predicted capacity.

  13. [The cholera epidemics in Córdoba as seen through the press: the supply of preservatives and cures during the 1867-1868 epidemic].

    Science.gov (United States)

    Carbonetti, Adrián; Rodríguez, María Laura; Noelia, Rimonda; Martina, Yamila

    2007-01-01

    Disease is always represented a moment of crisis for individuals and societies. When death brought by disease hangs heavy over societies, they are lead to develop strategies to prevent and cure it. Epidemics, especially cholera epidemics, have had a strong impact on Argentine society, especially on Cordoba residents, because the first cholera outbreak was highly devastating in both demographic and social terms. In this article we analyze the supply of products that were advertised in the press during the first epidemic, which broke out in 1867-68. Our basic hypothesis is that the products available developed a widespread trade that was not the object of commercial transactions common to those social grouping during periods in which there were no epidemics. When they took place, those products were directed towards more affluent groups.

  14. Effects of clustered transmission on epidemic growth Comment on "Mathematical models to characterize early epidemic growth: A review" by Gerardo Chowell et al.

    Science.gov (United States)

    Merler, Stefano

    2016-09-01

    Characterizing the early growth profile of an epidemic outbreak is key for predicting the likely trajectory of the number of cases and for designing adequate control measures. Epidemic profiles characterized by exponential growth have been widely observed in the past and a grounding theoretical framework for the analysis of infectious disease dynamics was provided by the pioneering work of Kermack and McKendrick [1]. In particular, exponential growth stems from the assumption that pathogens spread in homogeneous mixing populations; that is, individuals of the population mix uniformly and randomly with each other. However, this assumption was readily recognized as highly questionable [2], and sub-exponential profiles of epidemic growth have been observed in a number of epidemic outbreaks, including HIV/AIDS, foot-and-mouth disease, measles and, more recently, Ebola [3,4].

  15. Multiple routes transmitted epidemics on multiplex networks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dawei [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Shandong Provincial Key Laboratory of Computer Network, Shandong Computer Science Center, Jinan 250014 (China); Li, Lixiang [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Peng, Haipeng, E-mail: penghaipeng@bupt.edu.cn [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Luo, Qun; Yang, Yixian [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-02-01

    This letter investigates the multiple routes transmitted epidemic process on multiplex networks. We propose detailed theoretical analysis that allows us to accurately calculate the epidemic threshold and outbreak size. It is found that the epidemic can spread across the multiplex network even if all the network layers are well below their respective epidemic thresholds. Strong positive degree–degree correlation of nodes in multiplex network could lead to a much lower epidemic threshold and a relatively smaller outbreak size. However, the average similarity of neighbors from different layers of nodes has no obvious effect on the epidemic threshold and outbreak size. -- Highlights: •We studies multiple routes transmitted epidemic process on multiplex networks. •SIR model and bond percolation theory are used to analyze the epidemic processes. •We derive equations to accurately calculate the epidemic threshold and outbreak size. •ASN has no effect on the epidemic threshold and outbreak size. •Strong positive DDC leads to a lower epidemic threshold and a smaller outbreak size.

  16. 澜沧江苗尾水电站建设对自然疫源性疾病流行趋势影响分析%Analysis on epidemic tendency of zoonosis-borne diseases influence by Miaowei station construction

    Institute of Scientific and Technical Information of China (English)

    张腾; 王黎明; 肖义泽

    2011-01-01

    目的 为了解苗尾水电站工程建设及运行期间自然疫源性疾病流行趋势,分析水库蓄水、运行调度、施工人员进驻、工程施工和移民安置对库周人群健康的影响.方法 按照实施调查分析,收集有关疾病发病及传媒监测资料进行统计学分析.结果 2005-2009年施工区、淹没区和安置区涉及乡镇均无流行性出血热报告,自然人群流行性出血热抗体的检测结果显示2个区域的人群曾存在流行性出血热的感染;历史资料显示云龙县曾有过鼠疫暴发和流行,为鼠疫自然疫源地.结论 与环境变化关系较为密切的自然疫源性疾病存在局部流行或暴发的可能,应加强疾病监测和综合防控.%Objective To understand the epidemic tendency of zoonosis - borne diseases in Miaowei hydrupower station construction and course of operation, analyze the effect of reservoir, operation, constructor, engineering construction,relocation settlement on population health. Method Collecting the diseases and suneillance data of 2005 to 2009 and analyzed by technical specifications for medical assessment of environmental impact on water conservancy and hydroelectric projects. Results There was no epidemic hemorrhagic fever reported in construction area, inundated area and settlements from 2005 to 2009 , the results of epidemic hemorrhagic fever antibody in natural population showed that there existed epidemic hemorrhagic fever infection in this two area, history data showed that plague had outbreak and epidemic in Yunlong County. Conclusions Zoonosis - bome diseases which closely related to environment changes may outbreak and spread in local area, so we need to enhance monitoring and integrate control.

  17. Hepatocellular carcinoma and industrial epidemics

    Institute of Scientific and Technical Information of China (English)

    Alain Braillon; Gérard Dubois

    2011-01-01

    Worldwide, the burden of the non viral causes of hepatocellular carcinoma (HCC) is usually underestimated. Clearly industrial goods, tobacco, alcohol and processed foods are the agents of new epidemics in modern times which far outscore the burden of infectious agents on morbidity and mortality. Smoking, a dose-related contributing factor for HCC, receives too little attention in clinical practice. In France, tobacco, hepatitis B and C virus and alcohol are the main risk factors for HCC mortality (33%, 31% and 26%, respectively). In developing countries, where tobacco consumption is dramatically increasing, this epidemic may soon surpass hepatitis B. Obesity and diabetes are the contributing factors too. The role of industrial processed foods in the increase of the prevalence of obesity and diabetes cannot be ignored.

  18. Impact of preventive responses to epidemics in rural regions.

    Science.gov (United States)

    Schumm, Phillip; Schumm, Walter; Scoglio, Caterina

    2013-01-01

    Various epidemics have arisen in rural locations through human-animal interaction, such as the H1N1 outbreak of 2009. Through collaboration with local government officials, we have surveyed a rural county and its communities and collected a dataset characterizing the rural population. From the respondents' answers, we build a social (face-to-face) contact network. With this network, we explore the potential spread of epidemics through a Susceptible-Latent-Infected-Recovered (SLIR) disease model. We simulate an exact model of a stochastic SLIR Poisson process with disease parameters representing a typical influenza-like illness. We test vaccine distribution strategies under limited resources. We examine global and location-based distribution strategies, as a way to reach critical individuals in the rural setting. We demonstrate that locations can be identified through contact metrics for use in vaccination strategies to control contagious diseases.

  19. Epidemic spreading and immunization strategy in multiplex networks

    CERN Document Server

    Zuzek, Lucila G Alvarez; Braunstein, Lidia A

    2015-01-01

    A more connected world has brought major consequences such as facilitate the spread of diseases all over the world to quickly become epidemics, reason why researchers are concentrated in modeling the propagation of epidemics and outbreaks in Multilayer Networks. In this networks all nodes interact in different layers with different type of links. However, in many scenarios such as in the society, a Multiplex Network framework is not completely suitable since not all individuals participate in all layers. In this paper, we use a partially overlapped Multiplex Network where only a fraction of the individuals are shared by the layers. We develop a mitigation strategy for stopping a disease propagation, considering the Susceptible-Infected-Recover model, in a system consisted by two layers. We consider a random immunization in one of the layers and study the effect of the overlapping fraction in both, the propagation of the disease and the immunization strategy. Using branching theory, we study this scenario theo...

  20. Networked SIS Epidemics with Awareness

    CERN Document Server

    Paarporn, Keith; Weitz, Joshua S; Shamma, Jeff S

    2016-01-01

    We study an SIS epidemic process over a static contact network where the nodes have partial information about the epidemic state. They react by limiting their interactions with their neighbors when they believe the epidemic is currently prevalent. A node's awareness is weighted by the fraction of infected neighbors in their social network, and a global broadcast of the fraction of infected nodes in the entire network. The dynamics of the benchmark (no awareness) and awareness models are described by discrete-time Markov chains, from which mean-field approximations (MFA) are derived. The states of the MFA are interpreted as the nodes' probabilities of being infected. We show a sufficient condition for existence of a "metastable", or endemic, state of the awareness model coincides with that of the benchmark model. Furthermore, we use a coupling technique to give a full stochastic comparison analysis between the two chains, which serves as a probabilistic analogue to the MFA analysis. In particular, we show that...

  1. Understanding the Cholera Epidemic, Haiti

    Science.gov (United States)

    Barrais, Robert; Faucher, Benoît; Haus, Rachel; Piarroux, Martine; Gaudart, Jean; Magloire, Roc; Raoult, Didier

    2011-01-01

    After onset of a cholera epidemic in Haiti in mid-October 2010, a team of researchers from France and Haiti implemented field investigations and built a database of daily cases to facilitate identification of communes most affected. Several models were used to identify spatiotemporal clusters, assess relative risk associated with the epidemic’s spread, and investigate causes of its rapid expansion in Artibonite Department. Spatiotemporal analyses highlighted 5 significant clusters (p<0.001): 1 near Mirebalais (October 16–19) next to a United Nations camp with deficient sanitation, 1 along the Artibonite River (October 20–28), and 3 caused by the centrifugal epidemic spread during November. The regression model indicated that cholera more severely affected communes in the coastal plain (risk ratio 4.91) along the Artibonite River downstream of Mirebalais (risk ratio 4.60). Our findings strongly suggest that contamination of the Artibonite and 1 of its tributaries downstream from a military camp triggered the epidemic. PMID:21762567

  2. Contribution of hidden modes to nonlinear epidemic dynamics in urban human proximity networks

    CERN Document Server

    Fujiwara, Naoya; Iwayama, Koji; Aihara, Kazuyuki

    2015-01-01

    Recently developed techniques to acquire high-quality human mobility data allow large-scale simulations of the spread of infectious diseases with high spatial and temporal resolution.Analysis of such data has revealed the oversimplification of existing theoretical frameworks to infer the final epidemic size or influential nodes from the network topology. Here we propose a spectral decomposition-based framework for the quantitative analysis of epidemic processes on realistic networks of human proximity derived from urban mobility data. Common wisdom suggests that modes with larger eigenvalues contribute more to the epidemic dynamics. However, we show that hidden dominant structures, namely modes with smaller eigenvalues but a greater contribution to the epidemic dynamics, exist in the proximity network. This framework provides a basic understanding of the relationship between urban human motion and epidemic dynamics, and will contribute to strategic mitigation policy decisions.

  3. Monitoring linked epidemics: the case of tuberculosis and HIV.

    Directory of Open Access Journals (Sweden)

    María S Sánchez

    Full Text Available BACKGROUND: The tight epidemiological coupling between HIV and its associated opportunistic infections leads to challenges and opportunities for disease surveillance. METHODOLOGY/PRINCIPAL FINDINGS: We review efforts of WHO and collaborating agencies to track and fight the TB/HIV co-epidemic, and discuss modeling--via mathematical, statistical, and computational approaches--as a means to identify disease indicators designed to integrate data from linked diseases in order to characterize how co-epidemics change in time and space. We present R(TB/HIV, an index comparing changes in TB incidence relative to HIV prevalence, and use it to identify those sub-Saharan African countries with outlier TB/HIV dynamics. R(TB/HIV can also be used to predict epidemiological trends, investigate the coherency of reported trends, and cross-check the anticipated impact of public health interventions. Identifying the cause(s responsible for anomalous R(TB/HIV values can reveal information crucial to the management of public health. CONCLUSIONS/SIGNIFICANCE: We frame our suggestions for integrating and analyzing co-epidemic data within the context of global disease monitoring. Used routinely, joint disease indicators such as R(TB/HIV could greatly enhance the monitoring and evaluation of public health programs.

  4. Dynamics of Dengue epidemics using optimal control

    CERN Document Server

    Rodrigues, Helena Sofia; Torres, Delfim F M

    2010-01-01

    We present an application of optimal control theory to Dengue epidemics. This epidemiologic disease is an important theme in tropical countries due to the growing number of infected individuals. The dynamic model is described by a set of nonlinear ordinary differential equations, that depend on the dynamic of the Dengue mosquito, the number of infected individuals, and the people's motivation to combat the mosquito. The cost functional depends not only on the costs of medical treatment of the infected people but also on the costs related to educational and sanitary campaigns. Two approaches to solve the problem are considered: one using optimal control theory, another one by discretizing first the problem and then solving it with nonlinear programming. The results obtained with OC-ODE and IPOPT solvers are given and discussed. We observe that with current computational tools it is easy to obtain, in an efficient way, better solutions to Dengue problems, leading to a decrease of infected mosquitoes and individ...

  5. An etiological survey on a foodborne disease epidemic outbreak caused by salmonella enteritidis%一起由肠炎沙门菌所致食源性疾病暴发疫情的病原学研究

    Institute of Scientific and Technical Information of China (English)

    杨晋川; 夏杨; 郭惠; 许静静; 王路梅; 童晶; 张雷; 梁俊容; 景怀琦

    2013-01-01

    Objective To conduct an etiological molecular epidemiological survey and laboratory test on a foodborne disease epidemic outbreak to make clear of the cause and implement effective prevention and control on it.Methods On May 12th 2012,135 kindergarten children were sent to Xuzhou City People's Hospital and Children's Hospital with gastrointestinal infection disease.A total of 34 anus swabsamples and 4 vomit samples were collected from the patients.Real-time PCR rapid detection,strains separation and cultivation,phagelysis experiments,ATB automated identification system were used to make etiological detection and identification.The genomic DNA of salmonella enteritidis were typed with the pulsedfield gel electrophoresis (PFGE),cluster analysis were carried out together with the patterns of local Salmonella infections.Results Children in 20 classes were suffered from the gastrointestinal infection among the 21 classes.There were no significant aggregation of class distribution.Among the 135 patients,76 were boys (56.3%) and 59 were girls (43.7%).The main symptoms were fever(above 38 ℃),diarrhea and bellyache.Through real-time PCR detection and strains separation,19 salmonella enteritidis were isolated from 34 anus swab samples of suspected cases and the detection rate was 56%.Thcre were no strains detected from vomit samples.All of the 19 salmonella enteritidis showed the same serological subtype,biochemical reaction,drug sensitivity and phage lysis pattern.The salmonella enteritidis had the identical PFGE pattern (100% similarity),and were different from the pattern of local sporadic infection cases.Conclusion It was confirmed that this was an epidemic outbreak of foodborne disease caused by homologous salmonella entertidis by epidemiological survey,clinical information,lab etiological test and molecular typing.%目的 对一起食源性疾病暴发疫情进行病原学分子流行病学调查和细菌学检测,以便明确病因,进

  6. Malaria hotspot areas in a highland Kenya site are consistent in epidemic and non-epidemic years and are associated with ecological factors

    Directory of Open Access Journals (Sweden)

    Ernst Kacey C

    2006-09-01

    Full Text Available Abstract Background Malaria epidemics in highland areas of East Africa have caused considerable morbidity and mortality in the past two decades. Knowledge of "hotspot" areas of high malaria incidence would allow for focused preventive interventions in resource-poor areas, particularly if the hotspot areas can be discerned during non-epidemic periods and predicted by ecological factors. Methods To address this issue, spatial distribution of malaria incidence and the relationship of ecological factors to malaria incidence were assessed in the highland area of Kipsamoite, Kenya, from 2001–2004. Results Clustering of disease in a single geographic "hotspot" area occurred in epidemic and non-epidemic years, with a 2.6 to 3.2-fold increased risk of malaria inside the hotspot, as compared to outside the area (P Conclusion In this highland area, areas of high malaria risk are consistent in epidemic and non-epidemic years and are associated with specific ecological risk factors. Ongoing interventions in areas of ecological risk factors could be a cost-effective method of significantly reducing malaria incidence and blunting or preventing epidemics, even in the absence of malaria early warning systems. Further studies should be conducted to see if these findings hold true in varied highland settings.

  7. Epidemic spreading on evolving signed networks

    Science.gov (United States)

    Saeedian, M.; Azimi-Tafreshi, N.; Jafari, G. R.; Kertesz, J.

    2017-02-01

    Most studies of disease spreading consider the underlying social network as obtained without the contagion, though epidemic influences people's willingness to contact others: A "friendly" contact may be turned to "unfriendly" to avoid infection. We study the susceptible-infected disease-spreading model on signed networks, in which each edge is associated with a positive or negative sign representing the friendly or unfriendly relation between its end nodes. In a signed network, according to Heider's theory, edge signs evolve such that finally a state of structural balance is achieved, corresponding to no frustration in physics terms. However, the danger of infection affects the evolution of its edge signs. To describe the coupled problem of the sign evolution and disease spreading, we generalize the notion of structural balance by taking into account the state of the nodes. We introduce an energy function and carry out Monte Carlo simulations on complete networks to test the energy landscape, where we find local minima corresponding to the so-called jammed states. We study the effect of the ratio of initial friendly to unfriendly connections on the propagation of disease. The steady state can be balanced or a jammed state such that a coexistence occurs between susceptible and infected nodes in the system.

  8. The severe acute respiratory syndrome epidemic in mainland China dissected

    Directory of Open Access Journals (Sweden)

    Wuchun Cao

    2011-02-01

    Full Text Available This paper provides a review of a recently published series of studies that give a detailed and comprehensive documentation of the severe acute respiratory syndrome (SARS epidemic in mainland China, which severely struck the country in the spring of 2003. The epidemic spanned a large geographical extent but clustered in two areas: first in Guangdong Province, and about 3 months later in Beijing with its surrounding areas. Reanalysis of all available epidemiological data resulted in a total of 5327 probable cases of SARS, of whom 343 died. The resulting case fatality ratio (CFR of 6.4% was less than half of that in other SARS-affected countries or areas, and this difference could only partly be explained by younger age of patients and higher number of community acquired infections. Analysis of the impact of interventions demonstrated that strong political commitment and a centrally coordinated response was the most important factor to control SARS in mainland China, whereas the most stringent control measures were all initiated when the epidemic was already dying down. The long-term economic consequence of the epidemic was limited, much consumption was merely postponed, but for Beijing irrecoverable losses to the tourist sector were considerable. An important finding from a cohort study was that many former SARS patients currently suffer from avascular osteo­necrosis, as a consequence of the treatment with corticosteroids during their infection. The SARS epidemic provided valuable information and lessons relevant in controlling outbreaks of newly emerging infectious diseases, and has led to fundamental reforms of the Chinese health system. In particular, a comprehensive nation-wide internet-based disease reporting system was established.

  9. Planning horizon affects prophylactic decision-making and epidemic dynamics.

    Science.gov (United States)

    Nardin, Luis G; Miller, Craig R; Ridenhour, Benjamin J; Krone, Stephen M; Joyce, Paul; Baumgaertner, Bert O

    2016-01-01

    The spread of infectious diseases can be impacted by human behavior, and behavioral decisions often depend implicitly on a planning horizon-the time in the future over which options are weighed. We investigate the effects of planning horizons on epidemic dynamics. We developed an epidemiological agent-based model (along with an ODE analog) to explore the decision-making of self-interested individuals on adopting prophylactic behavior. The decision-making process incorporates prophylaxis efficacy and disease prevalence with the individuals' payoffs and planning horizon. Our results show that for short and long planning horizons individuals do not consider engaging in prophylactic behavior. In contrast, individuals adopt prophylactic behavior when considering intermediate planning horizons. Such adoption, however, is not always monotonically associated with the prevalence of the disease, depending on the perceived protection efficacy and the disease parameters. Adoption of prophylactic behavior reduces the epidemic peak size while prolonging the epidemic and potentially generates secondary waves of infection. These effects can be made stronger by increasing the behavioral decision frequency or distorting an individual's perceived risk of infection.

  10. Adolescents' explicit and implicit evaluations of hypothetical and actual peers with different bullying participant roles.

    Science.gov (United States)

    Pouwels, J Loes; Lansu, Tessa A M; Cillessen, Antonius H N

    2017-07-01

    This study examined how adolescents evaluate bullying at three levels of specificity: (a) the general concept of bullying, (b) hypothetical peers in different bullying participant roles, and (c) actual peers in different bullying participant roles. Participants were 163 predominantly ethnic majority adolescents in The Netherlands (58% girls; Mage=16.34years, SD=0.79). For the hypothetical peers, we examined adolescents' explicit evaluations as well as their implicit evaluations. Adolescents evaluated the general concept of bullying negatively. Adolescents' explicit evaluations of hypothetical and actual peers in the bullying roles depended on their own role, but adolescents' implicit evaluations of hypothetical peers did not. Adolescents' explicit evaluations of hypothetical peers and actual peers were different. Hypothetical bullies were evaluated negatively by all classmates, whereas hypothetical victims were evaluated relatively positively compared with the other roles. However, when adolescents evaluated their actual classmates, the differences between bullies and the other roles were smaller, whereas victims were evaluated the most negatively of all roles. Further research should take into account that adolescents' evaluations of hypothetical peers differ from their evaluations of actual peers. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. 47 CFR 69.608 - Carrier Common Line hypothetical net balance.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Carrier Common Line hypothetical net balance. 69.608 Section 69.608 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER... net balance. The hypothetical net balance shall be equal to a Carrier Common Line revenue...

  12. Combining aptamers and in silico interaction studies to decipher the function of hypothetical proteins

    DEFF Research Database (Denmark)

    Suravajhala, Prashanth; Burri, Harsha Vardhan Reddy; Heiskanen, Arto

    2014-01-01

    We present the potential role of aptamers in elucidating the function of hypothetical proteins, as well as the possibilities provided by bioinformatics for establishing a benchmark for aptamer-protein prediction methods. With these future perspectives, the role of hypothetical proteins as target ...

  13. THE RELATIONSHIp BETWEEN CAUSES AND DETERMINANTS OF JOB BURNOUT OF STAFF ENGAGING IN CONTROLLING EPIDEMIC DISEASE%传染病防疫人员职业倦怠的产生及其影响因素的相关研究

    Institute of Scientific and Technical Information of China (English)

    李霞; 谷金君; 李晓雯; 张雪芹; 吴秀荣

    2012-01-01

    [Objective] To analyze the relationship between job burnout and influential factors of staff in controlling epidemic disease, and to provide basic data for intervention. [Methods] This study used quantitative method to examine the relationship between job burnout, work pressure, responding strategies to work pressure, self-esteem and social support, conducted a survey of 200 staff working in epidemic disease control. I Results j The scores of job burnout in epidemic disease control were 54.97 ± 12.02, which was found positively related to work pressure, responding strategy but negatively correlated to self-esleera and social support. [Conclusion] The occurrence rate of job burnout of staff in controlling epidemic disease is relatively high because the increase in public incidences leads to heavy workload and high risk. High self-esteem, active responding strategy, and efficient social support play an important role in relieving the job burnout.%[目的]探讨传染病防疫人员职业倦怠的产生及其影响因素的关系,为进行干预提供参考依据.[方法]采用工作压力量表、工作压力应对策略调查表、自尊量表、社会支持量表、职业倦怠量表,对200名传染病防疫人员进行了调查,探讨各影响因素之间的相关性.[结果]其职业倦怠与工作压力、应对策略呈正相关、与自尊、社会支持呈负相关,传染病防疫人员职业倦怠评分为5497±12.02.[结论]传染病防疫人员职业倦怠发生率较高,主要因突发公共卫生事件的增多,导致工作量大且风险高而致.高自尊、积极的应对策略、有效的社会支持对缓解职业倦怠起到重要的作用.

  14. Competing activation mechanisms in epidemics on networks

    CERN Document Server

    Castellano, Claudio

    2011-01-01

    In stark contrast to previous common wisdom that epidemic activity and thresholds in heterogeneous networks are dominated by the elements with the largest number of connections (the hubs), recent research has pointed out the role of the most efficient spreaders, located at the innermost, dense core of the network, in sustaining epidemic processes. Here we show that the mechanism responsible of epidemic spreading depends on the dynamical pattern of the epidemic process. For epidemics with a transient state, activity is essentially boosted by the innermost core of the network. On the contrary, epidemics allowing a steady state present a dual scenario, where either the vertex with the largest connectivity independently sustains activity and propagates it to the rest of the system, or, alternatively, the innermost core of the network collectively turns into the active state, maintaining it on a global scale. Which one of these two mechanisms actually governs the dynamics depends on the network features. In uncorr...

  15. Rainfall mediations in the spreading of epidemic cholera

    Science.gov (United States)

    Righetto, L.; Bertuzzo, E.; Mari, L.; Schild, E.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2013-10-01

    Following the empirical evidence of a clear correlation between rainfall events and cholera resurgence that was observed in particular during the recent outbreak in Haiti, a spatially explicit model of epidemic cholera is re-examined. Specifically, we test a multivariate Poisson rainfall generator, with parameters varying in space and time, as a driver of enhanced disease transmission. The relevance of the issue relates to the key insight that predictive mathematical models may provide into the course of an ongoing cholera epidemic aiding emergency management (say, in allocating life-saving supplies or health care staff) or in evaluating alternative management strategies. Our model consists of a set of dynamical equations (SIRB-like i.e. subdivided into the compartments of Susceptible, Infected and Recovered individuals, and including a balance of Bacterial concentrations in the water reservoir) describing a connected network of human communities where the infection results from the exposure to excess concentrations of pathogens in the water. These, in turn, are driven by rainfall washout of open-air defecation sites or cesspool overflows, hydrologic transport through waterways and by mobility of susceptible and infected individuals. We perform an a posteriori analysis (from the beginning of the epidemic in October 2010 until December 2011) to test the model reliability in predicting cholera cases and in testing control measures, involving vaccination and sanitation campaigns, for the ongoing epidemic. Even though predicting reliably the timing of the epidemic resurgence proves difficult due to rainfall inter-annual variability, we find that the model can reasonably quantify the total number of reported infection cases in the selected time-span. We then run a multi-seasonal prediction of the course of the epidemic until December 2015, to investigate conditions for further resurgences and endemicity of cholera in the region with a view to policies which may bring to

  16. A canine distemper virus epidemic in Serengeti lions (Panthera leo).

    Science.gov (United States)

    Roelke-Parker, M E; Munson, L; Packer, C; Kock, R; Cleaveland, S; Carpenter, M; O'Brien, S J; Pospischil, A; Hofmann-Lehmann, R; Lutz, H; Mwamengele, G L; Mgasa, M N; Machange, G A; Summers, B A; Appel, M J

    1996-02-01

    Canine distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti-Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.

  17. A social contagious model of the obesity epidemic

    Science.gov (United States)

    Huang, He; Yan, Zhijun; Chen, Yahong; Liu, Fangyan

    2016-11-01

    Obesity has been recognized as a global epidemic by WHO, followed by many empirical evidences to prove its infectiousness. However, the inter-person spreading dynamics of obesity are seldom studied. A distinguishing feature of the obesity epidemic is that it is driven by a social contagion process which cannot be perfectly described by the infectious disease models. In this paper, we propose a novel belief decision model based on the famous Dempster-Shafer theory of evidence to model obesity epidemic as the competing spread of two obesity-related behaviors: physical inactivity and physical activity. The transition of health states is described by an SIS model. Results reveal the existence of obesity epidemic threshold, above which obesity is quickly eradicated. When increasing the fading level of information spread, enlarging the clustering of initial obese seeds, or introducing small-world characteristics into the network topology, the threshold is easily met. Social discrimination against the obese people plays completely different roles in two cases: on one hand, when obesity cannot be eradicated, social discrimination can reduce the number of obese people; on the other hand, when obesity is eradicable, social discrimination may instead cause it breaking out.

  18. Efficient mitigation strategies for epidemics in rural regions.

    Science.gov (United States)

    Scoglio, Caterina; Schumm, Walter; Schumm, Phillip; Easton, Todd; Roy Chowdhury, Sohini; Sydney, Ali; Youssef, Mina

    2010-07-13

    Containing an epidemic at its origin is the most desirable mitigation. Epidemics have often originated in rural areas, with rural communities among the first affected. Disease dynamics in rural regions have received limited attention, and results of general studies cannot be directly applied since population densities and human mobility factors are very different in rural regions from those in cities. We create a network model of a rural community in Kansas, USA, by collecting data on the contact patterns and computing rates of contact among a sampled population. We model the impact of different mitigation strategies detecting closely connected groups of people and frequently visited locations. Within those groups and locations, we compare the effectiveness of random and targeted vaccinations using a Susceptible-Exposed-Infected-Recovered compartmental model on the contact network. Our simulations show that the targeted vaccinations of only 10% of the sampled population reduced the size of the epidemic by 34.5%. Additionally, if 10% of the population visiting one of the most popular locations is randomly vaccinated, the epidemic size is reduced by 19%. Our results suggest a new implementation of a highly effective strategy for targeted vaccinations through the use of popular locations in rural communities.

  19. Neoliberal science, Chinese style: Making and managing the 'obesity epidemic'.

    Science.gov (United States)

    Greenhalgh, Susan

    2016-08-01

    Science and Technology Studies has seen a growing interest in the commercialization of science. In this article, I track the role of corporations in the construction of the obesity epidemic, deemed one of the major public health threats of the century. Focusing on China, a rising superpower in the midst of rampant, state-directed neoliberalization, I unravel the process, mechanisms, and broad effects of the corporate invention of an obesity epidemic. Largely hidden from view, Western firms were central actors at every stage in the creation, definition, and governmental management of obesity as a Chinese disease. Two industry-funded global health entities and the exploitation of personal ties enabled actors to nudge the development of obesity science and policy along lines beneficial to large firms, while obscuring the nudging. From Big Pharma to Big Food and Big Soda, transnational companies have been profiting from the 'epidemic of Chinese obesity', while doing little to effectively treat or prevent it. The China case suggests how obesity might have been constituted an 'epidemic threat' in other parts of the world and underscores the need for global frameworks to guide the study of neoliberal science and policymaking.

  20. Obesity and diabetes epidemics: cancer repercussions.

    Science.gov (United States)

    Hjartåker, Anette; Langseth, Hilde; Weiderpass, Elisabete

    2008-01-01

    environment that promotes sedentary lifestyles and over-consumption of energy. The health consequences and economic costs of the overweight, obesity and type II diabetes epidemics are enormous. Avoiding overweight and obesity, as well as preventing type II diabetes mellitus, is an important purpose to prevent cancer and other diseases. Prevention of obesity and type II diabetes should begin early in life and be based on the life-long health eating and physical activity patterns. Substantial public investments in preventing overweight, obesity and type II diabetes mellitus are both appropriate and necessary in order to have a major impact on their adverse health effects including cancer.

  1. Optimal vaccination and treatment of an epidemic network model

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lijuan [Department of Mathematics, Tongji University, Shanghai 200092 (China); College of Mathematics and Computer Science, Fuzhou University, Fuzhou, Fujian 350002 (China); Sun, Jitao, E-mail: sunjt@sh163.net [Department of Mathematics, Tongji University, Shanghai 200092 (China)

    2014-08-22

    In this Letter, we firstly propose an epidemic network model incorporating two controls which are vaccination and treatment. For the constant controls, by using Lyapunov function, global stability of the disease-free equilibrium and the endemic equilibrium of the model is investigated. For the non-constant controls, by using the optimal control strategy, we discuss an optimal strategy to minimize the total number of the infected and the cost associated with vaccination and treatment. Table 1 and Figs. 1–5 are presented to show the global stability and the efficiency of this optimal control. - Highlights: • Propose an optimally controlled SIRS epidemic model on heterogeneous networks. • Obtain criteria of global stability of the disease-free equilibrium and the endemic equilibrium. • Investigate existence of optimal control for the control problem. • The results be illustrated by some numerical simulations.

  2. [Increased epidemic incidence of hepatitis B in a district hospital].

    Science.gov (United States)

    Jakob, A; Mönch, E

    1978-01-15

    It is reported on an epidemic of hepatitis B of 29 patients in a district hospital. Due to diagnostic errors in importation and a more frequent appearance of diseases of hepatitis B in the surgical department and the 2nd medical department, in which above all diabetics are treated, took place. The average age of the patients was 55 years. In all patients the clinical course was to be regarded as severe. 4 of 29 patients died. In all patients the hepatitis B disease showed a pronounced jaundice with high transaminases, particularly the SGOT and LAP were clearly increased. Also the duration of the presence was longer than in hepatitis A as well as the transition into chronic hepatitis was more frequent. By diagnostic information of the physicians and the other medical staff as well as improved measures of desinfection the epidemic could be restricted.

  3. The role of immunity and seasonality in cholera epidemics.

    Science.gov (United States)

    Sanches, Rosângela P; Ferreira, Claudia P; Kraenkel, Roberto A

    2011-12-01

    This paper presents a mathematical model for cholera epidemics which comprises seasonality, loss of host immunity, and control mechanisms acting to reduce cholera transmission. A collection of data related to cholera disease allows us to show that outbreaks in endemic areas are subject to a resonant behavior, since the intrinsic oscillation period of the disease (∼1 year) is synchronized with the annual contact rate variation. Moreover, we argue that the short period of the host immunity may be associated to secondary peaks of incidence observed in some regions (a bimodal pattern). Finally, we explore some possible mechanisms of cholera control, and analyze their efficiency. We conclude that, besides mass vaccination--which may be impracticable--improvements in sanitation system and food/personal hygiene are the most effective ways to prevent an epidemic.

  4. The cancer, a silent epidemic.

    Directory of Open Access Journals (Sweden)

    Edith María Beltrán Molina

    2014-03-01

    Full Text Available This article deals with some very interesting aspects related to cancer the first cause of death in many countries with a high prevalence in Cuba so it is necessary to increase prevention and education to reduce risk factors and prevalence of malignancy. Taking into account the importance of cancer awareness as well as the social therapeutic and technological resources available to Cuba for its treatment it is propose with this work to exemplify the Cuban scientific treatment of cancer as a silent epidemic of the XXI century.

  5. SIS epidemic propagation on hypergraphs

    CERN Document Server

    Bodó, Ágnes; Simon, Péter L

    2015-01-01

    Mathematical modeling of epidemic propagation on networks is extended to hypergraphs in order to account for both the community structure and the nonlinear dependence of the infection pressure on the number of infected neighbours. The exact master equations of the propagation process are derived for an arbitrary hypergraph given by its incidence matrix. Based on these, moment closure approximation and mean-?eld models are introduced and compared to individual-based stochastic simulations. The simulation algorithm, developed for networks, is extended to hypergraphs. The e?ects of hypergraph structure and the model parameters are investigated via individual-based simulation results.

  6. Current Zika virus epidemiology and recent epidemics.

    Science.gov (United States)

    Ioos, S; Mallet, H-P; Leparc Goffart, I; Gauthier, V; Cardoso, T; Herida, M

    2014-07-01

    The Zika virus (ZIKV) is a mosquito-borne flavivirus (Aedes), similar to other arboviruses, first identified in Uganda in 1947. Few human cases were reported until 2007, when a Zika outbreak occurred in Yap, Micronesia, even though ZIKV activity had been reported in Africa and in Asia through virological surveillance and entomological studies. French Polynesia has recorded a large outbreak since October 2013. A great number of cases and some with neurological and autoimmune complications have been reported in a context of concurrent circulation of dengue viruses. The clinical presentation is a "dengue-like syndrome". Until the epidemic in French Polynesia, no severe ZIKV disease had been described so far. The diagnosis is confirmed by viral genome detection by genomic amplification (RT- PCR) and viral isolation. These two large outbreaks occurred in a previously unaffected area in less than a decade. They should raise awareness as to the potential for ZIKV to spread especially since this emergent disease is not well known and that some questions remain on potential reservoirs and transmission modes as well as on clinical presentations and complications. ZIKV has the potential to spread to new areas where the Aedes mosquito vector is present and could be a risk for Southern Europe. Strategies for the prevention and control of ZIKV disease should include the use of insect repellent and mosquito vector eradication.

  7. Spatially explicit modelling of cholera epidemics

    Science.gov (United States)

    Finger, F.; Bertuzzo, E.; Mari, L.; Knox, A. C.; Gatto, M.; Rinaldo, A.

    2013-12-01

    Epidemiological models can provide crucial understanding about the dynamics of infectious diseases. Possible applications range from real-time forecasting and allocation of health care resources to testing alternative intervention mechanisms such as vaccines, antibiotics or the improvement of sanitary conditions. We apply a spatially explicit model to the cholera epidemic that struck Haiti in October 2010 and is still ongoing. The dynamics of susceptibles as well as symptomatic and asymptomatic infectives are modelled at the scale of local human communities. Dissemination of Vibrio cholerae through hydrological transport and human mobility along the road network is explicitly taken into account, as well as the effect of rainfall as a driver of increasing disease incidence. The model is calibrated using a dataset of reported cholera cases. We further model the long term impact of several types of interventions on the disease dynamics by varying parameters appropriately. Key epidemiological mechanisms and parameters which affect the efficiency of treatments such as antibiotics are identified. Our results lead to conclusions about the influence of different intervention strategies on the overall epidemiological dynamics.

  8. GLOBAL STABILITY OF AN SVIR EPIDEMIC MODEL WITH VACCINATION

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this paper, an SIR epidemic model with vaccination for both the newborns and susceptibles is investigated, where it is assumed that the vaccinated individuals have the temporary immunity. The basic reproduction number determining the extinction or persistence of the infection is found. By constructing a Lyapunov function, it is proved that the disease free equilibrium is globally stable when the basic reproduction number is less than or equal to one, and that the endemic equilibrium is globally stable wh...

  9. SIVS EPIDEMIC MODELS WITH INFECTION AGE AND NONLINEAR VACCINATION RATE

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Vaccination is a very important strategy for the elimination of infectious diseaVaccination is a very important strategy for the elimination of infectious diseases. A SIVS epidemic model with infection age and nonlinear vaccination has been formulated in this paper. Using the theory of differential and integral equation, we show the local asymptotic stability of the infection-free equilibrium and the endemic equilibrium under some assumptions.

  10. Climate drives the meningitis epidemics onset in west Africa.

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    Benjamin Sultan

    2005-01-01

    Full Text Available BACKGROUND: Every year West African countries within the Sahelo-Sudanian band are afflicted with major meningococcal meningitis (MCM disease outbreaks, which affect up to 200,000 people, mainly young children, in one of the world's poorest regions. The timing of the epidemic year, which starts in February and ends in late May, and the spatial distribution of disease cases throughout the "Meningitis Belt" strongly indicate a close linkage between the life cycle of the causative agent of MCM and climate variability. However, mechanisms responsible for the observed patterns are still not clearly identified. METHODS AND FINDINGS: By comparing the information on cases and deaths of MCM from World Health Organization weekly reports with atmospheric datasets, we quantified the relationship between the seasonal occurrence of MCM in Mali, a West African country, and large-scale atmospheric circulation. Regional atmospheric indexes based on surface wind speed show a clear link between population dynamics of the disease and climate: the onset of epidemics and the winter maximum defined by the atmospheric index share the same mean week (sixth week of the year; standard deviation, 2 wk and are highly correlated. CONCLUSIONS: This study is the first that provides a clear, quantitative demonstration of the connections that exist between MCM epidemics and regional climate variability in Africa. Moreover, this statistically robust explanation of the MCM dynamics enables the development of an Early Warning Index for meningitis epidemic onset in West Africa. The development of such an index will undoubtedly help nationwide and international public health institutions and policy makers to better control MCM disease within the so-called westward-eastward pan-African Meningitis Belt.

  11. Epidemic spreading with time delay in complex networks

    CERN Document Server

    Xu, X J; Wang, X M; Wang, Y H

    2006-01-01

    We present a modified \\emph{susceptible-infected-susceptible} (SIS) model on complex networks, small-world and scale-free, to study epidemic spreading with the effect of time delay which is introduced to the infected phase. Considering the topology of the network, both uniform and degree-dependent delays are studied during the contagion process. We find that the existence of time delay will enhance both outbreaks and prevalence of infectious diseases in the network.

  12. [The Spanish flu epidemic: a challenge to Bahian medicine].

    Science.gov (United States)

    de Souza, Christiane Maria Cruz

    2008-01-01

    The article describes the moment when the medical and health authorities of Bahia state (Brazil) faced the challenge of explaining an illness that was spreading with unexpected virulency throughout the world, provoking much uncertainty and controversy among the global academic and scientific community concerning the diagnosis and etiology of the disease. It analyzes the Bahian medical establishment's stance within these discussions and the scientific knowledge used by medics to explain the epidemic and to recommend therapeutic and prophylactic measures.

  13. CE: Responding to the cholera epidemic in Haiti.

    Science.gov (United States)

    Fisher, Mary Lou Schulz; Wood, Tom; Plyler, Lance

    2014-05-01

    While Haiti was still recovering from the January 12, 2010, magnitude-7 earthquake, an outbreak of cholera spread throughout the nation, soon reaching epidemic proportions. Working through the faith-based nongovernmental organization Samaritan's Purse, an NP, an epidemiologist, and a physician joined the effort to prevent the spread of disease and treat those affected. Here they describe the prevention and intervention campaigns their organization initiated, how they prepared for each, and the essential elements of their operations.

  14. Epidemics scenarios in the "Romantic network".

    Directory of Open Access Journals (Sweden)

    Alexsandro M Carvalho

    Full Text Available The networks of sexual contacts together with temporal interactions play key roles in the spread of sexually transmitted infections. Unfortunately, data for this kind of network is scarce. One of the few exceptions, the "Romantic network", is a complete structure of a real sexual network in a high school. Based on many network measurements the authors of the work have concluded that it does not correspond to any other model network. Regarding the temporal structure, several studies indicate that relationship timing can have an effect on the diffusion throughout networks, as relationship order determines transmission routes. The aim is to check if the particular structure, static and dynamic, of the Romantic network is determinant for the propagation of an STI. We performed simulations in two scenarios: the static network where all contacts are available and the dynamic case where contacts evolve over time. In the static case, we compared the epidemic results in the Romantic network with some paradigmatic topologies. In the dynamic scenario, we considered the dynamics of formation of pairs in the Romantic network and we studied the propagation of the diseases. Our results suggest that although this real network cannot be labeled as a Watts-Strogatz network, it is, in regard to the propagation of an STI, very similar to a high disorder network. Additionally, we found that: the effect that any individual contacting an externally infected subject is to make the network closer to a fully connected one, the higher the contact degree of patient zero the faster the spread of the outbreaks, and the epidemic impact is proportional to the numbers of contacts per unit time. Finally, our simulations confirm that relationship timing severely reduced the final outbreak size, and also, show a clear correlation between the average degree and the outbreak size over time.

  15. Information content of household-stratified epidemics

    Directory of Open Access Journals (Sweden)

    T.M. Kinyanjui

    2016-09-01

    Full Text Available Household structure is a key driver of many infectious diseases, as well as a natural target for interventions such as vaccination programs. Many theoretical and conceptual advances on household-stratified epidemic models are relatively recent, but have successfully managed to increase the applicability of such models to practical problems. To be of maximum realism and hence benefit, they require parameterisation from epidemiological data, and while household-stratified final size data has been the traditional source, increasingly time-series infection data from households are becoming available. This paper is concerned with the design of studies aimed at collecting time-series epidemic data in order to maximize the amount of information available to calibrate household models. A design decision involves a trade-off between the number of households to enrol and the sampling frequency. Two commonly used epidemiological study designs are considered: cross-sectional, where different households are sampled at every time point, and cohort, where the same households are followed over the course of the study period. The search for an optimal design uses Bayesian computationally intensive methods to explore the joint parameter-design space combined with the Shannon entropy of the posteriors to estimate the amount of information in each design. For the cross-sectional design, the amount of information increases with the sampling intensity, i.e., the designs with the highest number of time points have the most information. On the other hand, the cohort design often exhibits a trade-off between the number of households sampled and the intensity of follow-up. Our results broadly support the choices made in existing epidemiological data collection studies. Prospective problem-specific use of our computational methods can bring significant benefits in guiding future study designs.

  16. An SIS Epidemic Model with Stage Structure and a Delay

    Institute of Scientific and Technical Information of China (English)

    Yah-ni Xiao; Lan-sun Chen

    2002-01-01

    A disease transmission model of SIS type with stage structure and a delay is formulated. Stability of the disease free equilibrium, and existence, uniqueness, and stability of an endemic equilibrium, are investigated for the model. The stability results are stated in terms of a key threshold parameter. The effects of stage structure and time delay on dynamical behavior of the infectious disease are analyzed. It is shown that stage structure has no effect on the epidemic model and Hopf bifurcation can occur as the time delay increases.

  17. Modeling and Analysis of Epidemic Diffusion within Small-World Network

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2012-01-01

    Full Text Available To depict the rule of epidemic diffusion, two different models, the Susceptible-Exposure-Infected-Recovered-Susceptible (SEIRS model and the Susceptible-Exposure-Infected-Quarantine-Recovered-Susceptible (SEIQRS model, are proposed and analyzed within small-world network in this paper. Firstly, the epidemic diffusion models are constructed with mean-filed theory, and condition for the occurrence of disease diffusion is explored. Then, the existence and global stability of the disease-free equilibrium and the endemic equilibrium for these two complex epidemic systems are proved by differential equations knowledge and Routh-Hurwiz theory. At last, a numerical example which includes key parameters analysis and critical topic discussion is presented to test how well the proposed two models may be applied in practice. These works may provide some guidelines for decision makers when coping with epidemic diffusion controlling problems.

  18. Epidemic suicide among Micronesian adolescents.

    Science.gov (United States)

    Rubinstein, D H

    1983-01-01

    Suicide rates since 1960 in Micronesia (the U.S. Trust Territory of the Pacific Islands) have undergone an epidemic-like increase. This phenomenon is focused narrowly within the 15--24-year male age-group. Extremely high rates and culturally patterned motives and methods are now characteristic of this group. Survey research throughout Micronesia suggests that the epidemic increase in adolescent male suicide is a cohort effect among the first post-war generation. Traditional adolescent socialization in pre-war Micronesia largely involved village-level subsistence activities organized around communal lineage-houses. This extra-familial level of socialization served as a cultural solution to the residential and psychological distance post-pubertal males maintained from their domestic families. With the post-war social change in Micronesia, the communal village-level of organization has largely disintegrated, causing adolescent socialization functions to be absorbed by the nuclear family. The resulting situations of intergenerational domestic discord appear the primary social triggers for adolescent suicide. At the same time, suicides have acquired subcultural significance among male youth, giving rise to fad-like and imitative acts. A 3-year research project is now being undertaken to conduct an ethnographic study of factors contributing to adolescent stress and suicide in one Micronesian community.

  19. A class of stochastic delayed SIR epidemic models with generalized nonlinear incidence rate and temporary immunity

    Science.gov (United States)

    Fan, Kuangang; Zhang, Yan; Gao, Shujing; Wei, Xiang

    2017-09-01

    A class of SIR epidemic model with generalized nonlinear incidence rate is presented in this paper. Temporary immunity and stochastic perturbation are also considered. The existence and uniqueness of the global positive solution is achieved. Sufficient conditions guaranteeing the extinction and persistence of the epidemic disease are established. Moreover, the threshold behavior is discussed, and the threshold value R0 is obtained. We show that if R0 1, then the system remains permanent in the mean.

  20. Temporal dynamics of connectivity and epidemic properties of growing networks

    Science.gov (United States)

    Fotouhi, Babak; Shirkoohi, Mehrdad Khani

    2016-01-01

    Traditional mathematical models of epidemic disease had for decades conventionally considered static structure for contacts. Recently, an upsurge of theoretical inquiry has strived towards rendering the models more realistic by incorporating the temporal aspects of networks of contacts, societal and online, that are of interest in the study of epidemics (and other similar diffusion processes). However, temporal dynamics have predominantly focused on link fluctuations and nodal activities, and less attention has been paid to the growth of the underlying network. Many real networks grow: Online networks are evidently in constant growth, and societal networks can grow due to migration flux and reproduction. The effect of network growth on the epidemic properties of networks is hitherto unknown, mainly due to the predominant focus of the network growth literature on the so-called steady state. This paper takes a step towards alleviating this gap. We analytically study the degree dynamics of a given arbitrary network that is subject to growth. We use the theoretical findings to predict the epidemic properties of the network as a function of time. We observe that the introduction of new individuals into the network can enhance or diminish its resilience against endemic outbreaks and investigate how this regime shift depends upon the connectivity of newcomers and on how they establish connections to existing nodes. Throughout, theoretical findings are corroborated with Monte Carlo simulations over synthetic and real networks. The results shed light on the effects of network growth on the future epidemic properties of networks and offers insights for devising a priori immunization strategies.