Science.gov

Sample records for contagious disease spread

  1. Early detection of contagious diseases

    DOEpatents

    Colston, Jr., Billy W. (San Ramon, CA); Milanovich, Fred P. (Lafayette, CA); Estacio, Pedro (Mission San Jose, CA); Chang, John (Walnut Creek, CA)

    2011-08-09

    This invention provides an electronic proximity apparatus and a surveillance method using such an apparatus for alerting individuals that are exposed to a contagious disease. When a person becomes symptomatic and is diagnosed as positive for a given contagious agent, individuals that have recently maintained a threshold proximity with respect to an infected individual are notified and advised to seek immediate medial care. Treatment of individuals in the very early phases of infection (pre-symptomatic) significantly reduces contagiousness of the infected population first exposed to the contagious disease, thus preventing spread of the disease throughout the general population.

  2. Childhood Contagious Diseases

    MedlinePLUS

    ... many childhood diseases, once contracted, result in lifelong immunity in the infected child. However, this is not always the case. Vaccinations also provide immunity to some of the below diseases. Chickenpox, for ...

  3. An Analytic Framework to Develop Policies for Testing, Prevention and Treatment of Two-stage Contagious Diseases

    E-print Network

    Gautam, Natarajan

    -stage Contagious Diseases Hoda Parvin, Department of Industrial and Operations Engineering University of Michigan in testing, preven- tion and cure of two-stage contagious diseases. An individual that has contracted the two-stage contagious disease will initially show no symptoms of the disease but is capable of spreading it

  4. Educating Children and Youth To Prevent Contagious Disease. ERIC Digest.

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    Twenty-first century contagious diseases require more than basic health lessons to prevent transmission. This Digest examines ways to prevent disease transmission in school settings. Section 1 discusses key concepts in contagion education: all people are potentially contagious; germs that cause diseases are present on many parts of the body; hand…

  5. CONTAGIOUS DISEASE MODULE FOR THE JOINT EFFECTS MODEL Mr. Jason Rodriguez, Ms. Karen E. Cheng, Dr. Gene E. McClellan, Dr. David J. Crary, and Dr.

    E-print Network

    Ray, Jaideep

    CONTAGIOUS DISEASE MODULE FOR THE JOINT EFFECTS MODEL Mr. Jason Rodriguez, Ms. Karen E. Cheng, Dr to modeling the spread of contagious diseases across a population-at-risk represented by the LandScan database used by the Joint Effects Model (JEM). We are implementing two models of disease transmission

  6. Should Persons with Contagious Diseases Be Barred from School?

    ERIC Educational Resources Information Center

    Roe, Richard L.

    1987-01-01

    Reviews recent court decisions regarding whether individuals with contagious diseases may be barred from public schools. Devotes specific attention to the issue of whether certain communicable diseases such as tuberculosis and Acquired Immune Deficiency Syndrome (AIDS) can be classified as handicaps and thereby qualify a person for protection…

  7. What To Do When Contagious Disease Strikes Your School.

    ERIC Educational Resources Information Center

    American Bar Association, Chicago, IL.

    This publication presents 10 documents collected to accompany a seminar entitled "What To Do When Contagious Disease Strikes Your School," presented at the 31st annual convention of the National Organization on Legal Problems of Education in 1985. The materials include (1) an agenda of the seminar listing the speakers, their topics, and the time…

  8. MHC gene copy number variation in Tasmanian devils: implications for the spread of a contagious cancer.

    PubMed

    Siddle, Hannah V; Marzec, Jolanta; Cheng, Yuanyuan; Jones, Menna; Belov, Katherine

    2010-07-01

    Tasmanian devils face extinction owing to the emergence of a contagious cancer. Devil facial tumour disease (DFTD) is a clonal cancer spread owing to a lack of major histocompatibility complex (MHC) barriers in Tasmanian devil populations. We present a comprehensive screen of MHC diversity in devils and identify 25 MHC types and 53 novel sequences, but conclude that overall levels of MHC diversity at the sequence level are low. The majority of MHC Class I variation can be explained by allelic copy number variation with two to seven sequence variants identified per individual. MHC sequences are divided into two distinct groups based on sequence similarity. DFTD cells and most devils have sequences from both groups. Twenty per cent of individuals have a restricted MHC repertoire and contain only group I or only group II sequences. Counterintuitively, we postulate that the immune system of individuals with a restricted MHC repertoire may recognize foreign MHC antigens on the surface of the DFTD cell. The implication of these results for management of DFTD and this endangered species are discussed. PMID:20219742

  9. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...contagious, infectious, or communicable disease, it becomes necessary to...

  10. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...contagious, infectious, or communicable disease, it becomes necessary to...

  11. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...contagious, infectious, or communicable disease, it becomes necessary to...

  12. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...contagious, infectious, or communicable disease, it becomes necessary to...

  13. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...poultry or other animals to prevent spread of disease; ascertainment of value and compensation...contagious, infectious, or communicable disease, it becomes necessary to...

  14. [Diagnosis of contagious diseases in animals using PCR].

    PubMed

    Hofmann, M A; Tratschin, J D; Brechtbühl, K; Griot, C

    1995-01-01

    The PCR is used for diagnostic purposes as it allows to detect infections agents within a much shorter time than by cultural isolation. In addition, it can detect non-infectious viruses and bacteria in clinical samples. These advantages are important factors in the diagnosis of highly contagious animal diseases (mainly caused by viruses) since a rapid laboratory diagnosis will allow to take immediate disease control actions. PCR is routinely used at the Institute of African and classical swine fever virus, foot and mouth disease virus, Aujeszky's disease virus, porcine reproductive and respiratory syndrome virus, as well as Newcastle disease virus. The isolate can be further characterized by direct nucleotide sequencing of the amplified DNA. Since reliability of the results as well as as prevention of contaminations are vital to PCR, this method should be carried out by appropriately trained personnel. In addition, it requires a high level of technical infrastructure. PMID:8584867

  15. Legal briefing: coerced treatment and involuntary confinement for contagious disease.

    PubMed

    Pope, Thaddeus Mason; Bughman, Heather Michelle

    2015-01-01

    This issue's "Legal Briefing" column covers recent legal developments involving coerced treatment and involuntary confinement for contagious disease. Recent high profile court cases involving measles, tuberculosis, human immunodeficiency virus, and especially Ebola, have thrust this topic back into the bioethics and public spotlights. This has reignited debates over how best to balance individual liberty and public health. For example, the Presidential Commission for the Study of Bioethical Issues has officially requested public comments, held open hearings, and published a 90-page report on "ethical considerations and implications" raised by "U.S. public policies that restrict association or movement (such as quarantine)." Broadly related articles have been published in previous issues of The Journal of Clinical Ethics. We categorize recent legal developments on coerced treatment and involuntary confinement into the following six categories: 1. Most Public Health Confinement Is Voluntary 2. Legal Requirements for Involuntary Confinement 3. New State Laws Authorizing Involuntary Confinement 4. Quarantine Must Be as Least Restrictive as Necessary 5. Isolation Is Justified Only as a Last Resort 6. Coerced Treatment after Persistent Noncompliance. PMID:25794297

  16. Finding Evidence for Local Transmission of Contagious Disease in Molecular Epidemiological Datasets

    PubMed Central

    Ypma, Rolf J. F.; Donker, Tjibbe; van Ballegooijen, W. Marijn; Wallinga, Jacco

    2013-01-01

    Surveillance systems of contagious diseases record information on cases to monitor incidence of disease and to evaluate effectiveness of interventions. These systems focus on a well-defined population; a key question is whether observed cases are infected through local transmission within the population or whether cases are the result of importation of infection into the population. Local spread of infection calls for different intervention measures than importation of infection. Besides standardized information on time of symptom onset and location of cases, pathogen genotyping or sequencing offers essential information to address this question. Here we introduce a method that takes full advantage of both the genetic and epidemiological data to distinguish local transmission from importation of infection, by comparing inter-case distances in temporal, spatial and genetic data. Cases that are part of a local transmission chain will have shorter distances between their geographical locations, shorter durations between their times of symptom onset and shorter genetic distances between their pathogen sequences as compared to cases that are due to importation. In contrast to generic clustering algorithms, the proposed method explicitly accounts for the fact that during local transmission of a contagious disease the cases are caused by other cases. No pathogen-specific assumptions are needed due to the use of ordinal distances, which allow for direct comparison between the disparate data types. Using simulations, we test the performance of the method in identifying local transmission of disease in large datasets, and assess how sensitivity and specificity change with varying size of local transmission chains and varying overall disease incidence. PMID:23922835

  17. Contagious Equine Metritis: A Review

    PubMed Central

    Eaglesome, M. D.; Garcia, M. M.

    1979-01-01

    Contagious equine metritis is a highly contagious genital infection of mares, spread venereally, and was first described in 1977. Although most contagious equine metritis outbreaks involved Thoroughbreds, infection in other breeds has also occurred. The disease has been reported in Europe, Australia and the United States. In Canada, contagious equine metritis has been designated a reportable disease under the Animal Disease and Protection Act. Contagious equine metritis is characterized by an endometritis and infertility and infected mares show no signs of systemic infection. Clinical signs have not been observed in stallions. An asymptomatic carrier state exists in both mares and stallions. Infected mares respond clinically to the topical and parenteral administration of antibacterial drugs. However, a proportion of mares remain carriers of the contagious equine metritis organism. Treatment of stallions is successful. Haemophilus equigenitalis has been proposed as the species name of the Gram-negative, microaerophilic coccobacillus. Sample collection and laboratory methods for the diagnosis of contagious equine metritis are described. PMID:389400

  18. Supreme Court Holds That Contagious Diseases Are Handicaps.

    ERIC Educational Resources Information Center

    Flygare, Thomas J.

    1987-01-01

    Describes a complex case involving termination of a third-grade teacher with recurrent tuberculosis. The United States Supreme Court upheld a circuit court's ruling that the teacher's condition satisfied section 504 of the 1973 Rehabilitation Act protecting handicapped persons against discrimination. Since contagiousness was not addressed, the…

  19. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... to prevent spread of disease; ascertainment of value and compensation. 71.14 Section 71.14 Animals... or other animals to prevent spread of disease; ascertainment of value and compensation. When, in order to prevent the spread of any contagious, infectious, or communicable disease, it becomes...

  20. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... to prevent spread of disease; ascertainment of value and compensation. 71.14 Section 71.14 Animals... or other animals to prevent spread of disease; ascertainment of value and compensation. When, in order to prevent the spread of any contagious, infectious, or communicable disease, it becomes...

  1. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... to prevent spread of disease; ascertainment of value and compensation. 71.14 Section 71.14 Animals... or other animals to prevent spread of disease; ascertainment of value and compensation. When, in order to prevent the spread of any contagious, infectious, or communicable disease, it becomes...

  2. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... to prevent spread of disease; ascertainment of value and compensation. 71.14 Section 71.14 Animals... or other animals to prevent spread of disease; ascertainment of value and compensation. When, in order to prevent the spread of any contagious, infectious, or communicable disease, it becomes...

  3. 9 CFR 71.14 - Slaughter of poultry or other animals to prevent spread of disease; ascertainment of value and...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... to prevent spread of disease; ascertainment of value and compensation. 71.14 Section 71.14 Animals... or other animals to prevent spread of disease; ascertainment of value and compensation. When, in order to prevent the spread of any contagious, infectious, or communicable disease, it becomes...

  4. Respiratory-borne Disease Outbreaks in Populations: Contact Networks and the Spread of Disease

    NASA Astrophysics Data System (ADS)

    Pourbohloul, Babak; Meyers, Lauren A.; Newman, Mark E. J.; Skowronski, Danuta M.

    2005-03-01

    A large class of infectious diseases spread through direct person-to-person contact. Traditional ``compartmental'' modeling in epidemiology assumes that in population groups every individual has an equal chance of spreading the disease to every other. The patterns of these contacts, however, tend to be highly heterogeneous. Explicit models of the patterns of contact among individuals in a community, contact network models, underlie a powerful approach to predicting and controlling the spread of such infectious disease and provide detailed and valuable insight into the fate and control of an outbreak. We use contact network epidemiology to predict the impact of various control policies for both a mildly contagious disease such as SARS and a more highly contagious disease such as smallpox. We demonstrate how integrating these tools into public health decision-making should facilitate more rational strategies for managing newly emerging diseases, bioterrorism and pandemic influenza in situations where empirical data are not yet available to guide decision making.

  5. Prevent the Spread of Zoonotic Diseases A zoonotic disease is a disease that can be shared between

    E-print Network

    care of animals, take the following precautions against spreading germs that cause diseases. Wear the risk of exposing other animals or people to contagious diseases. Wear boots and a set of protective clothing that you· wear only when handling and caring for animals. Examples are hat coveralls long

  6. [Management of highly contagious, life-threatening infectious diseases in Germany].

    PubMed

    Gottschalk, René

    2015-07-01

    Highly contagious, life-threatening infectious diseases are extremely rare in Germany. It was estimated that Germany experiences approximately one such patient per year, but records since the year 2000 demonstrate that this has not been the case (six cases). Even during the current Ebola outbreak in West Africa, Germany is not experiencing patients-apart from those referred to by international organisations. However, it is necessary to establish and maintain specialised treatment centres for patients with highly contagious, life-threatening diseases. Highly contagious, life-threatening diseases are rare and neglected diseases, yet they can have devastating effects on individual patients, societies and entire economies. A dedicated expert group was formed at the German Robert Koch Institute (STAKOB) to network and synthesise the different centres of competence and treatment. This group prepares recommendations that encompass the early detection and treatment of patients to infectious disease management to mitigate the implications on societies and interrupt the chain of infections to safeguard the integrity of public health in Germany. PMID:25963639

  7. Contagious Diseases in Competitive Sport: What Are the Risks?

    ERIC Educational Resources Information Center

    Dorman, John M.

    2000-01-01

    Discusses fungal, bacterial, and viral infections that may strike athletes during competition, highlighting possible risks of hepatitis, herpes, and HIV. Athletes generally are more at risk off the playing field than while competing. Requiring immunizations against measles and hepatitis B prior to college admission would eliminate two diseases.…

  8. Contagious rhythm: infectious diseases of 20th century musicians.

    PubMed

    Sartin, Jeffrey S

    2010-07-01

    Infectious diseases have led to illness and death for many famous musicians, from the classical period to the rock 'n' roll era. By the 20th century, as public health improved and orchestral composers began living more settled lives, infections among American and European musicians became less prominent. By mid-century, however, seminal jazz musicians famously pursued lifestyles characterized by drug and alcohol abuse. Among the consequences of this risky lifestyle were tuberculosis, syphilis, and chronic viral hepatitis. More contemporary rock musicians have experienced an epidemic of hepatitis C infection and HIV/AIDS related to intravenous drug use and promiscuity. Musical innovation is thus often accompanied by diseases of neglect and overindulgence, particularly infectious illnesses, although risky behavior and associated infectious illnesses tend to decrease as the style matures. PMID:20660936

  9. Contagious Rhythm: Infectious Diseases of 20th Century Musicians

    PubMed Central

    Sartin, Jeffrey S.

    2010-01-01

    Infectious diseases have led to illness and death for many famous musicians, from the classical period to the rock ’n’ roll era. By the 20th century, as public health improved and orchestral composers began living more settled lives, infections among American and European musicians became less prominent. By mid-century, however, seminal jazz musicians famously pursued lifestyles characterized by drug and alcohol abuse. Among the consequences of this risky lifestyle were tuberculosis, syphilis, and chronic viral hepatitis. More contemporary rock musicians have experienced an epidemic of hepatitis C infection and HIV/AIDS related to intravenous drug use and promiscuity. Musical innovation is thus often accompanied by diseases of neglect and overindulgence, particularly infectious illnesses, although risky behavior and associated infectious illnesses tend to decrease as the style matures. PMID:20660936

  10. A generic model of contagious disease and its application to human-to-human transmission of avian influenza.

    SciTech Connect

    Hirsch, Gary B.

    2007-03-01

    Modeling contagious diseases has taken on greater importance over the past several years as diseases such as SARS and avian influenza have raised concern about worldwide pandemics. Most models developed to consider projected outbreaks have been specific to a single disease. This paper describes a generic System Dynamics contagious disease model and its application to human-to-human transmission of a mutant version of avian influenza. The model offers the option of calculating rates of new infections over time based either on a fixed ''reproductive number'' that is traditional in contagious disease models or on contact rates for different sub-populations and likelihood of transmission per contact. The paper reports on results with various types of interventions. These results suggest the potential importance of contact tracing, limited quarantine, and targeted vaccination strategies as methods for controlling outbreaks, especially when vaccine supplies may initially be limited and the efficacy of anti-viral drugs uncertain.

  11. Multi Criteria Decision Making to evaluate control strategies of contagious animal diseases.

    PubMed

    Mourits, M C M; van Asseldonk, M A P M; Huirne, R B M

    2010-09-01

    The decision on which strategy to use in the control of contagious animal diseases involves complex trade-offs between multiple objectives. This paper describes a Multi Criteria Decision Making (MCDM) application to illustrate its potential support to policy makers in choosing the control strategy that best meets all of the conflicting interests. The presented application focused on the evaluation of alternative strategies to control Classical Swine Fever (CSF) epidemics within the European Union (EU) according to the preferences of the European Chief Veterinary Officers (CVO). The performed analysis was centred on the three high-level objectives of epidemiology, economics and social ethics. The appraised control alternatives consisted of the EU compulsory control strategy, a pre-emptive slaughter strategy, a protective vaccination strategy and a suppressive vaccination strategy. Using averaged preference weights of the elicited CVOs, the preference ranking of the control alternatives was determined for six EU regions. The obtained results emphasized the need for EU region-specific control. Individual CVOs differed in their views on the relative importance of the various (sub)criteria by which the performance of the alternatives were judged. Nevertheless, the individual rankings of the control alternatives within a region appeared surprisingly similar. Based on the results of the described application it was concluded that the structuring feature of the MCDM technique provides a suitable tool in assisting the complex decision making process of controlling contagious animal diseases. PMID:20633939

  12. Evolution of a contagious cancer: epigenetic variation in Devil Facial Tumour Disease.

    PubMed

    Ujvari, Beata; Pearse, Anne-Maree; Peck, Sarah; Harmsen, Collette; Taylor, Robyn; Pyecroft, Stephen; Madsen, Thomas; Papenfuss, Anthony T; Belov, Katherine

    2013-01-01

    The emergence of Devil Facial Tumour Disease (DFTD), a highly contagious cancer, is driving Tasmanian devils (Sarcophilus harrisii) to extinction. The cancer is a genetically and chromosomally stable clonal cell line which is transmitted by biting during social interactions. In the present study, we explore the Devil Facial Tumour (DFT) epigenome and the genes involved in DNA methylation homeostasis. We show that tumour cells have similar levels of methylation to peripheral nerves, the tissue from which DFTD originated. We did not observe any strain or region-specific epimutations. However, we revealed a significant increase in hypomethylation in DFT samples over time (p < 0.0001). We propose that loss of methylation is not because of a maintenance deficiency, as an upregulation of DNA methyltransferase 1 gene was observed in tumours compared with nerves (p < 0.005). Instead, we believe that loss of methylation is owing to active demethylation, supported by the temporal increase in MBD2 and MBD4 (p < 0.001). The implications of these changes on disease phenotypes need to be explored. Our work shows that DFTD should not be treated as a static entity, but rather as an evolving parasite with epigenetic plasticity. Understanding the role of epimutations in the evolution of this parasitic cancer will provide unique insights into the role of epigenetic plasticity in cancer evolution and progression in traditional cancers that arise and die with their hosts. PMID:23135679

  13. Modeling spatial spread of communicable diseases involving

    E-print Network

    Ruan, Shigui

    CHAPTER 15 Modeling spatial spread of communicable diseases involving animal hosts Shigui Ruan on modeling spatial spread of specific communicable diseases involving animal hosts. Reaction-diffusion equations are used to model these diseases due to movement of animal hosts. Selected topics include

  14. Nosocomial Spread of Viral Disease

    PubMed Central

    Aitken, Celia; Jeffries, Donald J.

    2001-01-01

    Viruses are important causes of nosocomial infection, but the fact that hospital outbreaks often result from introduction(s) from community-based epidemics, together with the need to initiate specific laboratory testing, means that there are usually insufficient data to allow the monitoring of trends in incidences. The most important defenses against nosocomial transmission of viruses are detailed and continuing education of staff and strict adherence to infection control policies. Protocols must be available to assist in the management of patients with suspected or confirmed viral infection in the health care setting. In this review, we present details on general measures to prevent the spread of viral infection in hospitals and other health care environments. These include principles of accommodation of infected patients and approaches to good hygiene and patient management. They provide detail on individual viral diseases accompanied in each case with specific information on control of the infection and, where appropriate, details of preventive and therapeutic measures. The important areas of nosocomial infection due to blood-borne viruses have been extensively reviewed previously and are summarized here briefly, with citation of selected review articles. Human prion diseases, which present management problems very different from those of viral infection, are not included. PMID:11432812

  15. [Epidemiology of Ebola virus disease and of other highly contagious, life-threatening diseases with low incidence in Germany].

    PubMed

    Ehlkes, L; Kreuels, B; Schwarz, N G; May, Jürgen

    2015-07-01

    Apart from sporadic exported cases, the occurrence of Ebola, Marburg and Lassa virus diseases is limited to the African continent. Crimean-Congo Hemorrhagic Fever occurs in Southeastern Europe but, so far, not in Germany. Other hemorrhagic fever disease-viruses occur in distinct regions in South America. Pulmonary plague is the bacterial infectious disease with the most contagious and lethal course and it is endemic to Madagascar and East Africa, but also occurs in other countries (e.g. India, USA). Monkey pox epidemics have occurred in remote areas of the Congo Basin. Such outbreaks could potentially become more common with the discontinuation of the cross-protective smallpox vaccination. The Severe Acute Respiratory Syndrome (SARS) that emerged in 2002/2003 is another pathogen with significant epidemic potential. Typical for these diseases is a natural circulation between reservoir animals in remote areas. Sporadic transmission to humans can occur through contact with an infected animal. Subsequent human-to-human transmission can lead to epidemics, such as the current outbreak of Ebola virus disease in West Africa. PMID:25997608

  16. [Importation of rare but life-threatening and highly contagious diseases. Current situation and outlook].

    PubMed

    Burchard, G D

    2015-10-01

    Internists should expect to be the first contact for patients with rare, but highly contagious, life-threatening illnesses. Although certainly not encountered often, it is associated with significant consequences. Thus, physicians should be familiar with viral hemorrhagic fevers: filoviruses cause Ebola and Marburg fever, arenaviruses cause Lassa fever and South American hemorrhagic fevers, and the bunyaviruses cause among others Crimean-Congo hemorrhagic fever. Furthermore, physicians should be familiar with highly contagious respiratory infections, such as hantavirus pulmonary syndrome, pneumonic plague, and Middle East respiratory syndrome (MERS). PMID:26391557

  17. Reversible epigenetic down-regulation of MHC molecules by devil facial tumour disease illustrates immune escape by a contagious cancer.

    PubMed

    Siddle, Hannah V; Kreiss, Alexandre; Tovar, Cesar; Yuen, Chun Kit; Cheng, Yuanyuan; Belov, Katherine; Swift, Kate; Pearse, Anne-Maree; Hamede, Rodrigo; Jones, Menna E; Skjødt, Karsten; Woods, Gregory M; Kaufman, Jim

    2013-03-26

    Contagious cancers that pass between individuals as an infectious cell line are highly unusual pathogens. Devil facial tumor disease (DFTD) is one such contagious cancer that emerged 16 y ago and is driving the Tasmanian devil to extinction. As both a pathogen and an allograft, DFTD cells should be rejected by the host-immune response, yet DFTD causes 100% mortality among infected devils with no apparent rejection of tumor cells. Why DFTD cells are not rejected has been a question of considerable confusion. Here, we show that DFTD cells do not express cell surface MHC molecules in vitro or in vivo, due to down-regulation of genes essential to the antigen-processing pathway, such as ?2-microglobulin and transporters associated with antigen processing. Loss of gene expression is not due to structural mutations, but to regulatory changes including epigenetic deacetylation of histones. Consequently, MHC class I molecules can be restored to the surface of DFTD cells in vitro by using recombinant devil IFN-?, which is associated with up-regulation of the MHC class II transactivator, a key transcription factor with deacetylase activity. Further, expression of MHC class I molecules by DFTD cells can occur in vivo during lymphocyte infiltration. These results explain why T cells do not target DFTD cells. We propose that MHC-positive or epigenetically modified DFTD cells may provide a vaccine to DFTD. In addition, we suggest that down-regulation of MHC molecules using regulatory mechanisms allows evolvability of transmissible cancers and could affect the evolutionary trajectory of DFTD. PMID:23479617

  18. Modeling of Disease Spreading on Trees Mentor: Professor Partha Dey

    E-print Network

    Poonen, Bjorn

    Modeling of Disease Spreading on Trees Daniel Guo Mentor: Professor Partha Dey PRIMES Conference May 16, 2015 Daniel Guo (PRIMES Conference) Modeling of Disease Spreading on Trees May 16, 2015 1 / 22 and Continuation 4 References Daniel Guo (PRIMES Conference) Modeling of Disease Spreading on Trees May 16, 2015 2

  19. Spread of epidemic disease on networks

    NASA Astrophysics Data System (ADS)

    Newman, M. E.

    2002-07-01

    The study of social networks, and in particular the spread of disease on networks, has attracted considerable recent attention in the physics community. In this paper, we show that a large class of standard epidemiological models, the so-called susceptible/infective/removed (SIR) models can be solved exactly on a wide variety of networks. In addition to the standard but unrealistic case of fixed infectiveness time and fixed and uncorrelated probability of transmission between all pairs of individuals, we solve cases in which times and probabilities are nonuniform and correlated. We also consider one simple case of an epidemic in a structured population, that of a sexually transmitted disease in a population divided into men and women. We confirm the correctness of our exact solutions with numerical simulations of SIR epidemics on networks.

  20. How Long Is Mono Contagious?

    MedlinePLUS

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español ... Guy's Guide to Body Image How Long Is Mono Contagious? KidsHealth > Teens > ...

  1. Contagious cancer.

    PubMed

    Welsh, James S

    2011-01-01

    Although cancer can on occasion be caused by infectious agents such as specific bacteria, parasites, and viruses, it is not generally considered a transmissible disease. In rare circumstances, however, direct communication from one host to another has been documented. The Tasmanian devil is now threatened with extinction in the wild because of a fatal transmissible cancer, devil facial tumor disease (DFTD). Another example is canine transmissible venereal tumor (CTVT or Sticker's sarcoma) in dogs. There is a vast difference in prognosis between these two conditions. DFTD is often fatal within 6 months, whereas most cases of CTVT are eventually rejected by the host dog, who then is conferred lifelong immunity. In man, only scattered case reports exist about such communicable cancers, most often in the setting of organ or hematopoietic stem cell transplants and cancers arising during pregnancy that are transmitted to the fetus. In about one third of cases, transplant recipients develop cancers from donor organs from individuals who were found to harbor malignancies after the transplantation. The fact that two thirds of the time cancer does not develop, along with the fact that cancer very rarely is transmitted from person to person, supports the notion that natural immunity prevents such cancers from taking hold in man. These observations might hold invaluable clues to the immunobiology and possible immunotherapy of cancer. PMID:21212437

  2. A Computational Model of Mitigating Disease Spread in Spatial Networks

    E-print Network

    Buffalo, State University of New York

    A Computational Model of Mitigating Disease Spread in Spatial Networks Taehyong Kim1 , Kang Li1 consider the problem of disease spreading and containment in spatial networks, where our computational model is capable of detecting disease progression to initiate processes mitigating infection

  3. Modeling daily flow patterns individuals to characterize disease spread

    SciTech Connect

    Smallwood, J.; Hyman, J. M.; Mirchandani, Pitu B.

    2002-11-17

    The effect of an individual's travels throughout a day on the spread of disease is examined using a deterministic SIR model. We determine which spatial and demographic characteristics most contribute to the disease spread and whether the progression of the disease can be slowed by appropriate vaccination of people belonging to a specific location-type.

  4. Spreading of sexually transmitted diseases in heterosexual populations

    E-print Network

    Gómez-Gardenes, J; Moreno, Y; Profumo, E V

    2007-01-01

    Disease spreading is a topical issue in a variety of fields ranging from computer viruses in the Internet to air-borne (e.g. influenza) diseases in societies. In particular, the description of the spread of sexually transmitted diseases (Chlamydia, Syphilis, Gonorrhea, AIDS) across population constitutes a major concern for scientists and health agencies. In this context, both data collection on sexual contact networks and the modeling of disease spreading are intensively contributing to the search for effective immunization policies. Here, the spread of sexually transmitted diseases on bipartite scale-free graphs, representing heterosexual contact networks, is considered. We analytically derive the expression for the epidemic threshold and its dependence with the system size in finite populations. The results indicate that in finite bipartite populations with degree distribution as those found in national surveys of sexual attitudes, the onset of the epidemic outbreak takes place for larger spreading rates t...

  5. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Control of livestock disease and introduction of livestock. 167...REGULATIONS § 167.15 Control of livestock disease and introduction of livestock...and spread of contagious or infectious disease in the economic interest of the...

  6. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Control of livestock disease and introduction of livestock. 167...REGULATIONS § 167.15 Control of livestock disease and introduction of livestock...and spread of contagious or infectious disease in the economic interest of the...

  7. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Control of livestock disease and introduction of livestock. 167...REGULATIONS § 167.15 Control of livestock disease and introduction of livestock...and spread of contagious or infectious disease in the economic interest of the...

  8. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Control of livestock disease and introduction of livestock. 167...REGULATIONS § 167.15 Control of livestock disease and introduction of livestock...and spread of contagious or infectious disease in the economic interest of the...

  9. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2011-04-01 true Control of livestock disease and introduction of livestock. 167...REGULATIONS § 167.15 Control of livestock disease and introduction of livestock...and spread of contagious or infectious disease in the economic interest of the...

  10. Dealing with American Foulbrood American foulbrood (AFB) is a highly contagious bacterial disease of honey bee larvae. Diseased colonies usually

    E-print Network

    Ishida, Yuko

    of honey bee larvae. Diseased colonies usually die. The unprotected, spore-contaminated nectar, honey inoculum to the next colonies. There is no method by which your bees can be prevented from robbing a dying or dead colony. So, if you are keeping bees in an area known to have a history of American foulbrood

  11. Emotions are not always contagious: Longitudinal spreading of self-pride and group pride in homogeneous and status-differentiated groups.

    PubMed

    Delvaux, Ellen; Meeussen, Loes; Mesquita, Batja

    2016-01-01

    The members of task groups are emotionally more similar to each other than to others outside the group; yet, little is known about the conditions under which this emotional similarity emerges. In two longitudinal studies, we tested the idea that emotions only spread when they contain information that is relevant to all group members. We compared the spreading of group pride (relevant) with self-pride (not relevant). The first study followed emotions in 68 task groups (N = 295) across 4 moments. Multilevel cross-lagged path analyses showed that group members mutually influenced each other's group pride, but not self-pride. The second study followed emotions in 27 task groups (N = 195) across 3 moments in time. Longitudinal social network analyses showed that group members adjusted their group pride, but not their self-pride, to members they perceived to be more influential. Findings from both studies are consistent with a social referencing account of emotion spreading. PMID:25786806

  12. The Committee Studying Contagious Disease Training for Public Safety Personnel. Report of the Committee on Training of the Criminal Justice Services Board to the Governor and the General Assembly of Virginia. House Document No. 15.

    ERIC Educational Resources Information Center

    Virginia State Dept. of Criminal Justice Services, Richmond.

    Through discussion and extensive research, the Committee Studying Contagious Disease Training attempted to address concerns regarding education and training of public safety personnel with regard to human immunodeficiency virus (HIV) and hepatitis B virus (HBV). The committee's findings were based on Occupational Safety and Health Administration…

  13. Global Transport Networks and Infectious Disease Spread

    PubMed Central

    Tatem, A.J.; Rogers, D.J.; Hay, S.I.

    2011-01-01

    Air, sea and land transport networks continue to expand in reach, speed of travel and volume of passengers and goods carried. Pathogens and their vectors can now move further, faster and in greater numbers than ever before. Three important consequences of global transport network expansion are infectious disease pandemics, vector invasion events and vector-borne pathogen importation. This review briefly examines some of the important historical examples of these disease and vector movements, such as the global influenza pandemics, the devastating Anopheles gambiae invasion of Brazil and the recent increases in imported Plasmodium falciparum malaria cases. We then outline potential approaches for future studies of disease movement, focussing on vector invasion and vector-borne disease importation. Such approaches allow us to explore the potential implications of international air travel, shipping routes and other methods of transport on global pathogen and vector traffic. PMID:16647974

  14. Prevent the Spread of Zoonotic Diseases 

    E-print Network

    Pena, Josefa

    2008-11-10

    they are up-to-date on vaccinations? parasite prevention? veterinary visits ? Observe your animals for any signs of disease. Signs of illness to watch for are diarrhea? vomiting? not eating or drinking? weakness? sneezing? coughing? nasal...

  15. Spatial spread of farm animal diseases

    E-print Network

    Vernon, Matthew Christopher

    of movement data. By using simulated diseases, the serious shortcomings of static network representations compared to more complex dynamic network representations were demonstrated. A substantial library of software for the generation and analysis of large...

  16. Techniques for Preventing the Spread of Infectious Diseases.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento.

    Specific procedures are outlined for prevention of the spread of infectious diseases with techniques of handwashing, diapering, and handling of known disease carriers. Protocols for classroom cleanliness list essential steps and key points and precautions for maintaining a hygienic environment. This section includes a list of protocols for food…

  17. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...transmission, or spread of communicable diseases. 1271.145 Section 1271.145...transmission, or spread of communicable diseases. You must recover, process...transmission, or spread of communicable...

  18. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...transmission, or spread of communicable diseases. 1271.145 Section 1271.145...transmission, or spread of communicable diseases. You must recover, process...transmission, or spread of communicable...

  19. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...transmission, or spread of communicable diseases. 1271.145 Section 1271.145...transmission, or spread of communicable diseases. You must recover, process...transmission, or spread of communicable...

  20. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...transmission, or spread of communicable diseases. 1271.145 Section 1271.145...transmission, or spread of communicable diseases. You must recover, process...transmission, or spread of communicable...

  1. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...transmission, or spread of communicable diseases. 1271.145 Section 1271.145...transmission, or spread of communicable diseases. You must recover, process...transmission, or spread of communicable...

  2. Marek’s disease virus pathogenesis and latency 

    E-print Network

    Hunter, Gillian

    2012-11-30

    Marek’s Disease virus (MDV) is a highly contagious, widespread and persistent neoplastic ?-herpesvirus causing extensive lymphoblastic tumours in chickens. The virus is shed in feather dust and spread through inhalation. ...

  3. [Cortical spreading depolarization: a new pathophysiological mechanism in neurological diseases].

    PubMed

    Sánchez-Porras, Renán; Robles-Cabrera, Adriana; Santos, Edgar

    2014-05-20

    Cortical spreading depolarization is a wave of almost complete depolarization of the neuronal and glial cells that occurs in different neurological diseases such as migraine with aura, subarachnoid hemorrhage, intracerebral hemorrhage, head trauma and stroke. These depolarization waves are characterized by a change in the negative potential with an amplitude between -10 and -30mV, duration of ?1min and changes in the ion homeostasis between the intra- and extracellular space. This results in neuronal edema and dendritic distortion. Under pathologic states of hypoperfusion, cortical spreading depolarization can produce oxidative stress, worsen hypoxia and induce neuronal death. This is due to intense arterial vasoconstriction produced by an inverse response called spreading ischemia. Only in the last years there has been an electrophysiological confirmation of cortical spreading depolarization in human brains. Occurrence of cortical spreading depolarization has been associated with worse outcome in patients. Currently, increased knowledge regarding the pathophysiologic mechanisms supports the hypothetical correlation of cortical spreading depolarization with brain damage in humans. There are diverse therapeutic alternatives that promise inhibition of cortical spreading depolarization and subsequent better outcomes. PMID:23928069

  4. Modelling power-law spread of infectious diseases

    E-print Network

    Meyer, Sebastian

    2013-01-01

    Short-time human travel behaviour can be well described by a power law with respect to distance. We incorporate this information in space-time models for infectious disease surveillance data to better capture the dynamics of disease spread. Two previously established model classes are extended, which both decompose disease risk additively into endemic and epidemic components: a space-time point process model for individual point-referenced data, and a multivariate time series model for aggregated count data. In both frameworks, the power-law spread is embedded into the epidemic component and its decay parameter is estimated simultaneously with all other unknown parameters using (penalised) likelihood inference. The performance of the new approach is investigated by a re-analysis of individual cases of invasive meningococcal disease in Germany (2002-2008), and count data on influenza in 140 administrative districts of Southern Germany (2001-2008). In both applications, the power-law formulations substantially ...

  5. Mathematical analysis of dynamic spread of Pine Wilt disease.

    PubMed

    Dimitrijevic, D D; Bacic, J

    2013-01-01

    Since its detection in Portugal in 1999, the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer), a causal agent of Pine Wilt Disease, represents a threat to European forestry. Significant amount of money has been spent on its monitoring and eradication. This paper presents mathematical analysis of spread of pine wilt disease using a set of partial differential equations with space (longitude and latitude) and time as parameters of estimated spread of disease. This methodology can be used to evaluate risk of various assumed entry points of disease and make defense plans in advance. In case of an already existing outbreak, it can be used to draw optimal line of defense and plan removal of trees. Optimization constraints are economic loss of removal of susceptible trees as well as budgetary constraints of workforce cost. PMID:25151817

  6. What's the Difference Between Infectious and Contagious?

    MedlinePLUS

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español ... Guy's Guide to Body Image What's the Difference Between Infectious and Contagious? ...

  7. Evaluating the links between climate, disease spread, and amphibian declines

    E-print Network

    Rohr, Jason

    Evaluating the links between climate, disease spread, and amphibian declines Jason R. Rohra,1 propelled the Earth into its sixth mass extinction event and amphibians, the most threatened of all vertebrate taxa, are at the forefront. Many of the worldwide amphibian declines have been caused

  8. Spreading of diseases through comorbidity networks across life and gender

    NASA Astrophysics Data System (ADS)

    Chmiel, Anna; Klimek, Peter; Thurner, Stefan

    2014-11-01

    The state of health of patients is typically not characterized by a single disease alone but by multiple (comorbid) medical conditions. These comorbidities may depend strongly on age and gender. We propose a specific phenomenological comorbidity network of human diseases that is based on medical claims data of the entire population of Austria. The network is constructed from a two-layer multiplex network, where in one layer the links represent the conditional probability for a comorbidity, and in the other the links contain the respective statistical significance. We show that the network undergoes dramatic structural changes across the lifetime of patients. Disease networks for children consist of a single, strongly interconnected cluster. During adolescence and adulthood further disease clusters emerge that are related to specific classes of diseases, such as circulatory, mental, or genitourinary disorders. For people over 65 these clusters start to merge, and highly connected hubs dominate the network. These hubs are related to hypertension, chronic ischemic heart diseases, and chronic obstructive pulmonary diseases. We introduce a simple diffusion model to understand the spreading of diseases on the disease network at the population level. For the first time we are able to show that patients predominantly develop diseases that are in close network proximity to disorders that they already suffer. The model explains more than 85% of the variance of all disease incidents in the population. The presented methodology could be of importance for anticipating age-dependent disease profiles for entire populations, and for design and validation of prevention strategies.

  9. Protein aggregate spreading in neurodegenerative diseases: Problems and perspectives

    PubMed Central

    Lee, Seung-Jae; Lim, Hee-Sun; Masliah, Eliezer; Lee, He-Jin

    2014-01-01

    Progressive accumulation of specific protein aggregates is a defining feature of many major neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, fronto-temporal dementia, Huntington’s disease, and Creutzfeldt–Jakob disease (CJD). Findings from several recent studies have suggested that aggregation-prone proteins, such as tau, ?-synuclein, polyglutamine-containing proteins, and amyloid-?, can spread to other cells and brain regions, a phenomenon considered unique to prion disorders, such as CJD and bovine spongiform encephalopathy. Cell-to-cell propagation of protein aggregates may be the general underlying principle for progressive deterioration of neurodegenerative diseases. This may also have significant implications in cell replacement therapies, as evidenced by the propagation of ?-synuclein aggregates from host to grafted cells in long-term transplants in Parkinson’s patients. Here, we review recent progress in protein aggregate propagation in experimental model systems and discuss outstanding questions and future perspectives. Understanding the mechanisms of this pathological spreading may open the way to unique opportunities for development of diagnostic techniques and novel therapies for protein misfolding-associated neurodegenerative diseases. PMID:21624403

  10. In vivo infection biology of contagious bovine pleuropneumonia 

    E-print Network

    Gull, Tamara Brownsey

    2009-05-15

    Contagious Bovine Pleuropneumonia (CBPP), caused by Mycoplasma mycoides mycoides small colony (MmmSC), is a devastating respiratory disease of cattle in Africa, Asia and the Middle East. Little investigation has been done ...

  11. Spread of Infectious Diseases with a Latent Period

    E-print Network

    Mizuno, Kanako

    2015-01-01

    Infectious diseases spread through human networks. Susceptible-Infected-Removed (SIR) model is one of the epidemic models to describe infection dynamics on a complex network connecting individuals. In the metapopulation SIR model, each node represents a population (group) which has many individuals. In this paper, we propose a modified metapopulation SIR model in which a latent period is taken into account. We call it SIIR model. We divide the infection period into two stages: an infected stage, which is the same as the previous model, and a seriously ill stage, in which individuals are infected and cannot move to the other populations. The two infectious stages in our modified metapopulation SIR model produce a discontinuous final size distribution. Individuals in the infected stage spread the disease like individuals in the seriously ill stage and never recover directly, which makes an effective recovery rate smaller than the given recovery rate.

  12. The landscape genetics of infectious disease emergence and spread

    PubMed Central

    Biek, Roman; Real, Leslie A.

    2011-01-01

    The spread of parasites is inherently a spatial process often embedded in physically complex landscapes. It is therefore not surprising that infectious disease researchers are increasingly taking a landscape genetics perspective to elucidate mechanisms underlying basic ecological processes driving infectious disease dynamics and to understand the linkage between spatially-dependent population processes and the geographic distribution of genetic variation within both hosts and parasites. The increasing availability of genetic information on hosts and parasites when coupled to their ecological interactions can lead to insights for predicting patterns of disease emergence, spread, and control. Here, we review research progress in this area based on four different motivations for the application of landscape genetics approaches: (1) assessing the spatial organization of genetic variation in parasites as a function of environmental variability, (2) using host population genetic structure as a means to parameterize ecological dynamics that indirectly influence parasite populations, e.g. gene flow and movement pathways across heterogeneous landscapes and the concurrent transport of infectious agents, (3) elucidating the temporal and spatial scales of disease processes, and (4) reconstructing and understanding infectious disease invasion. Throughout this review, we emphasise that landscape genetic principles are relevant to infection dynamics across a range of scales from within host dynamics to global geographic patterns and that they can also be applied to unconventional “landscapes” such as heterogeneous contact networks underlying the spread of human and livestock diseases. We conclude by discussing some general considerations and problems for inferring epidemiological processes from genetic data and try to identify possible future directions and applications for this rapidly expanding field. PMID:20618897

  13. Airborne spread of foot-and-mouth disease - model intercomparison

    SciTech Connect

    Gloster, J; Jones, A; Redington, A; Burgin, L; Sorensen, J H; Turner, R; Dillon, M; Hullinger, P; Simpson, M; Astrup, P; Garner, G; Stewart, P; D'Amours, R; Sellers, R; Paton, D

    2008-09-04

    Foot-and-mouth disease is a highly infectious vesicular disease of cloven-hoofed animals caused by foot-and-mouth disease virus. It spreads by direct contact between animals, by animal products (milk, meat and semen), by mechanical transfer on people or fomites and by the airborne route - with the relative importance of each mechanism depending on the particular outbreak characteristics. Over the years a number of workers have developed or adapted atmospheric dispersion models to assess the risk of foot-and-mouth disease virus spread through the air. Six of these models were compared at a workshop hosted by the Institute for Animal Health/Met Office during 2008. A number of key issues emerged from the workshop and subsequent modelling work: (1) in general all of the models predicted similar directions for 'at risk' livestock with much of the remaining differences strongly related to differences in the meteorological data used; (2) determination of an accurate sequence of events is highly important, especially if the meteorological conditions vary substantially during the virus emission period; and (3) differences in assumptions made about virus release, environmental fate, and subsequent infection can substantially modify the size and location of the downwind risk area. Close relationships have now been established between participants, which in the event of an outbreak of disease could be readily activated to supply advice or modelling support.

  14. The Development of Software Tools for Monitoring the Spread of Disease

    E-print Network

    Poonen, Bjorn

    of Software Tools for Monitoring the Spread of Disease By Albert Gerovitch, Andrew Gritsevskiy, and Gregory;______________________________________________________________________________________________________________________ Introduction It is of great interest to understand the spread of disease on a local level. However, obtaining localized data and tracking and monitoring spread of disease of individuals is still a big challenge

  15. Asymptomatic spread of huanglongbing and implications for disease control

    PubMed Central

    Lee, Jo Ann; Halbert, Susan E.; Dawson, William O.; Robertson, Cecile J.; Keesling, James E.; Singer, Burton H.

    2015-01-01

    Huanglongbing (HLB) is a bacterial infection of citrus trees transmitted by the Asian citrus psyllid Diaphorina citri. Mitigation of HLB has focused on spraying of insecticides to reduce the psyllid population and removal of trees when they first show symptoms of the disease. These interventions have been only marginally effective, because symptoms of HLB do not appear on leaves for months to years after initial infection. Limited knowledge about disease spread during the asymptomatic phase is exemplified by the heretofore unknown length of time from initial infection of newly developing cluster of young leaves, called flush, by adult psyllids until the flush become infectious. We present experimental evidence showing that young flush become infectious within 15 d after receiving an inoculum of Candidatus Liberibacter asiaticus (bacteria). Using this critical fact, we specify a microsimulation model of asymptomatic disease spread and intensity in a grove of citrus trees. We apply a range of psyllid introduction scenarios to show that entire groves can become infected with up to 12,000 psyllids per tree in less than 1 y, before most of the trees show any symptoms. We also show that intervention strategies that reduce the psyllid population by 75% during the flushing periods can delay infection of a full grove, and thereby reduce the amount of insecticide used throughout a year. This result implies that psyllid surveillance and control, using a variety of recently available technologies, should be used from the initial detection of invasion and throughout the asymptomatic period. PMID:26034273

  16. Asymptomatic spread of huanglongbing and implications for disease control.

    PubMed

    Lee, Jo Ann; Halbert, Susan E; Dawson, William O; Robertson, Cecile J; Keesling, James E; Singer, Burton H

    2015-06-16

    Huanglongbing (HLB) is a bacterial infection of citrus trees transmitted by the Asian citrus psyllid Diaphorina citri. Mitigation of HLB has focused on spraying of insecticides to reduce the psyllid population and removal of trees when they first show symptoms of the disease. These interventions have been only marginally effective, because symptoms of HLB do not appear on leaves for months to years after initial infection. Limited knowledge about disease spread during the asymptomatic phase is exemplified by the heretofore unknown length of time from initial infection of newly developing cluster of young leaves, called flush, by adult psyllids until the flush become infectious. We present experimental evidence showing that young flush become infectious within 15 d after receiving an inoculum of Candidatus Liberibacter asiaticus (bacteria). Using this critical fact, we specify a microsimulation model of asymptomatic disease spread and intensity in a grove of citrus trees. We apply a range of psyllid introduction scenarios to show that entire groves can become infected with up to 12,000 psyllids per tree in less than 1 y, before most of the trees show any symptoms. We also show that intervention strategies that reduce the psyllid population by 75% during the flushing periods can delay infection of a full grove, and thereby reduce the amount of insecticide used throughout a year. This result implies that psyllid surveillance and control, using a variety of recently available technologies, should be used from the initial detection of invasion and throughout the asymptomatic period. PMID:26034273

  17. Spread of lumpy skin disease in Israeli dairy herds.

    PubMed

    Yeruham, I; Nir, O; Braverman, Y; Davidson, M; Grinstein, H; Haymovitch, M; Zamir, O

    1995-07-22

    Fourteen of the 17 dairy herds in Peduyim, an Israeli village, became infected with lumpy skin disease during a period of 37 days in August and September 1989. One cow in one neighbouring village and four cows in another neighbouring village also became infected, probably through being treated by a veterinarian who treated cows in Peduyim. Circumstantial evidence suggests that the original infection was brought to Peduyim and spread by stable flies (Stomoxys calcitrans) carried by the wind from foci of the disease at El Arish in northern Sinai, or at Ismailiya and the Nile delta in Egypt. All the cattle and the small flocks of sheep and goats in the village were slaughtered. PMID:8533249

  18. Computational Study of Ventilation and Disease Spread in Poultry Houses

    NASA Astrophysics Data System (ADS)

    Cimbala, John; Pawar, Sourabh; Wheeler, Eileen; Lindberg, Darla

    2006-11-01

    The air flow in and around poultry houses has been studied numerically with the goal of determining disease spread characteristics and comparing ventilation schemes. A typical manure-belt layer egg production facility is considered. The continuity, momentum, and energy equations are solved for flow both inside and outside poultry houses using the commercial computational fluid dynamics (CFD) code FLUENT. Both simplified two-dimensional and fully three-dimensional geometries are modeled. The spread of virus particles is considered to be analogous to diffusion of a tracer contaminant gas, in this case ammonia. The effect of thermal plumes produced by the hens in the poultry house is also considered. Two ventilation schemes with opposite flow directions are compared. Contours of temperature and ammonia mass fraction for both cases are obtained and compared. The analysis shows that ventilation and air quality characteristics are much better for the case in which the air flow is from bottom to top (enhancing the thermal plume) instead of from top to bottom (fighting the thermal plume) as in most poultry houses. This has implications in air quality control in the event of epidemic outbreaks of avian flu or other infectious diseases.

  19. Edge-based compartmental modelling for infectious disease spread

    PubMed Central

    Miller, Joel C.; Slim, Anja C.; Volz, Erik M.

    2012-01-01

    The primary tool for predicting infectious disease spread and intervention effectiveness is the mass action susceptible–infected–recovered model of Kermack & McKendrick. Its usefulness derives largely from its conceptual and mathematical simplicity; however, it incorrectly assumes that all individuals have the same contact rate and partnerships are fleeting. In this study, we introduce edge-based compartmental modelling, a technique eliminating these assumptions. We derive simple ordinary differential equation models capturing social heterogeneity (heterogeneous contact rates) while explicitly considering the impact of partnership duration. We introduce a graphical interpretation allowing for easy derivation and communication of the model and focus on applying the technique under different assumptions about how contact rates are distributed and how long partnerships last. PMID:21976638

  20. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... spread of communicable diseases. 1271.145 Section 1271.145 Food and Drugs FOOD AND DRUG ADMINISTRATION... diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test cell... diseases....

  1. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... spread of communicable diseases. 1271.145 Section 1271.145 Food and Drugs FOOD AND DRUG ADMINISTRATION... diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test cell... diseases....

  2. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... spread of communicable diseases. 1271.145 Section 1271.145 Food and Drugs FOOD AND DRUG ADMINISTRATION... diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test cell... diseases....

  3. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... spread of communicable diseases. 1271.145 Section 1271.145 Food and Drugs FOOD AND DRUG ADMINISTRATION... diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test cell... diseases....

  4. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... spread of communicable diseases. 1271.145 Section 1271.145 Food and Drugs FOOD AND DRUG ADMINISTRATION... diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test cell... diseases....

  5. Key Node Selection for Containing Infectious Disease Spread Using Particle Swarm Optimization

    E-print Network

    Wong, Limsoon

    Key Node Selection for Containing Infectious Disease Spread Using Particle Swarm Optimization Xiuju infectious diseases have grown into global health threats due to high human mobility. It is important to have intervention plans for containing the spread of such infectious diseases. Among various intervention strategies

  6. An Intuitive Formulation for the Reproductive Number for the Spread of Diseases in

    E-print Network

    Hyman, James "Mac"

    An Intuitive Formulation for the Reproductive Number for the Spread of Diseases in Heterogeneous dynamics of a disease and can guide strategies to control its spread. We de#12;ne the mean number of mathematical epidemiology is to #12;nd threshold conditions that determine whether an infectious disease

  7. Alpha-synuclein spreading in Parkinson’s disease

    PubMed Central

    Recasens, Ariadna; Dehay, Benjamin

    2014-01-01

    Formation and accumulation of misfolded protein aggregates are a central hallmark of several neurodegenerative diseases. In Parkinson’s disease (PD), the aggregation-prone protein alpha-synuclein (?-syn) is the culprit. In the past few years, another piece of the puzzle has been added with data suggesting that ?-syn may self-propagate, thereby contributing to the progression and extension of PD. Of particular importance, it was the seminal observation of Lewy bodies (LB), a histopathological signature of PD, in grafted fetal dopaminergic neurons in the striatum of PD patients. Consequently, these findings were a conceptual breakthrough, generating the “host to graft transmission” hypothesis, also called the “prion-like hypothesis.” Several in vitro and in vivo studies suggest that ?-syn can undergo a toxic templated conformational change, spread from cell to cell and from region to region, and initiate the formation of “LB–like aggregates,” contributing to the PD pathogenesis. Here, we will review and discuss the current knowledge for such a putative mechanism on the prion-like nature of ?-syn, and discuss about the proper use of the term prion-like. PMID:25565982

  8. Contagious cancer: lessons from the devil and the dog.

    PubMed

    Belov, Katherine

    2012-04-01

    Cancer is generally defined as uncontrollable growth of cells caused by genetic aberrations and/or environmental factors. Yet contagious cancers also occur. The recent emergence of a contagious cancer in Tasmanian devils has reignited interest in transmissible cancers. Two naturally occurring transmissible cancers are known: devil facial tumour disease and canine transmissible venereal tumour. Both cancers evolved once and have then been transmitted from one individual to another as clonal cell lines. The dog cancer is ancient; having evolved more than 6,000 years ago, while the devil disease was first seen in 1996. In this review I will compare and contrast the two diseases focusing on the life histories of the clonal cell lines, their evolutionary trajectories and the mechanisms by which they have achieved immune tolerance. A greater understanding of these contagious cancers will provide unique insights into the role of the immune system in shaping tumour evolution and may uncover novel approaches for treating human cancer. PMID:22383221

  9. FluPhone Study: Virtual Disease Spread using Haggle Eiko Yoneki

    E-print Network

    Hand, Steven

    such as swine flu spread so fast. In many ways, the concept of PSNs is analogous to how infectious diseasesFluPhone Study: Virtual Disease Spread using Haggle Eiko Yoneki University of Cambridge, Computer Laboratory Cambridge CB3 0FD, United Kingdom eiko.yoneki@cl.cam.ac.uk ABSTRACT This paper introduces the Flu

  10. Genetic bases for Marek's disease resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek's disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by MD virus (MDV). Therefore, the control of MD is of particular concern to the poultry industry. The poultry industry has been heavily relying on biosecurity and vaccination to control the spread and occurren...

  11. InterSpread Plus: a spatial and stochastic simulation model of disease in animal populations.

    PubMed

    Stevenson, M A; Sanson, R L; Stern, M W; O'Leary, B D; Sujau, M; Moles-Benfell, N; Morris, R S

    2013-04-01

    We describe the spatially explicit, stochastic simulation model of disease spread, InterSpread Plus, in terms of its epidemiological framework, operation, and mode of use. The input data required by the model, the method for simulating contact and infection spread, and methods for simulating disease control measures are described. Data and parameters that are essential for disease simulation modelling using InterSpread Plus are distinguished from those that are non-essential, and it is suggested that a rational approach to simulating disease epidemics using this tool is to start with core data and parameters, adding additional layers of complexity if and when the specific requirements of the simulation exercise require it. We recommend that simulation models of disease are best developed as part of epidemic contingency planning so decision makers are familiar with model outputs and assumptions and are well-positioned to evaluate their strengths and weaknesses to make informed decisions in times of crisis. PMID:22995473

  12. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle...

  13. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle...

  14. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle...

  15. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle...

  16. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 ...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle...

  17. Modelling the initial spread of foot-and-mouth disease through animal movements

    E-print Network

    Kiss, Istvan Zoltan

    Modelling the initial spread of foot-and-mouth disease through animal movements D. M. Green*, I. Z, as in the 2001 epidemic of foot-and-mouth disease (FMD) in the UK. Here, the movement data are used to construct of England than elsewhere. Keywords: modelling; epidemiology; foot-and-mouth disease 1. INTRODUCTION Control

  18. The role of spatial mixing in the spread of foot-and-mouth disease

    E-print Network

    Hyman, James "Mac"

    The role of spatial mixing in the spread of foot-and-mouth disease G. Chowell a,b,Ã , A.L. Rivas on the 2001 Uruguayan foot-and-mouth disease epidemic), was used for testing. Significant differences between. Keywords: Foot-and-mouth disease; Spatial mathematical model; Reproductive number; Uruguay; Movement

  19. Modeling social response to the spread of an infectious disease

    E-print Network

    Evans, Jane A. (Jane Amanda)

    2012-01-01

    With the globalization of culture and economic trade, it is increasingly important not only to detect outbreaks of infectious disease early, but also to anticipate the social response to the disease. In this thesis, we use ...

  20. Spreading of infectious diseases on complex networks with non-symmetric transmission probabilities

    E-print Network

    Britta Daudert; Bai-Lian Li

    2006-11-23

    We model the spread of a SIS infection on Small World and random networks using weighted graphs. The entry $w_{ij}$ in the weight matrix W holds information about the transmission probability along the edge joining node $v_i$ and node $v_j$. We use the analogy between the spread of a disease on a network and a random walk performed on this network to derive a master equation describing the dynamics of the process. We find conditions under which an epidemic does not break out and investigate numerically the effect of a non-symmetric weight distribution of the initially infected individual on the dynamics of the disease spread.

  1. Crisis Management Simulation: Spread of Diseases in National University of Singapore

    NASA Astrophysics Data System (ADS)

    Tan, Gary S. H.; Lau, R.

    In an attempt to study the spread of diseases in the National University of Singapore (NUS), a simulation model unique to the NUS environment was developed to evaluate the effectiveness of different intervention policies during the event of a disease outbreak. The system allows the user to introduce a user-defined disease into the NUS population to study its impact. The effectiveness of various intervention policies on selected diseases are evaluated and presented in the paper.

  2. Evaluating the links between climate, disease spread, and amphibian declines.

    PubMed

    Rohr, Jason R; Raffel, Thomas R; Romansic, John M; McCallum, Hamish; Hudson, Peter J

    2008-11-11

    Human alteration of the environment has arguably propelled the Earth into its sixth mass extinction event and amphibians, the most threatened of all vertebrate taxa, are at the forefront. Many of the worldwide amphibian declines have been caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), and two contrasting hypotheses have been proposed to explain these declines. Positive correlations between global warming and Bd-related declines sparked the chytrid-thermal-optimum hypothesis, which proposes that global warming increased cloud cover in warm years that drove the convergence of daytime and nighttime temperatures toward the thermal optimum for Bd growth. In contrast, the spatiotemporal-spread hypothesis states that Bd-related declines are caused by the introduction and spread of Bd, independent of climate change. We provide a rigorous test of these hypotheses by evaluating (i) whether cloud cover, temperature convergence, and predicted temperature-dependent Bd growth are significant positive predictors of amphibian extinctions in the genus Atelopus and (ii) whether spatial structure in the timing of these extinctions can be detected without making assumptions about the location, timing, or number of Bd emergences. We show that there is spatial structure to the timing of Atelopus spp. extinctions but that the cause of this structure remains equivocal, emphasizing the need for further molecular characterization of Bd. We also show that the reported positive multi-decade correlation between Atelopus spp. extinctions and mean tropical air temperature in the previous year is indeed robust, but the evidence that it is causal is weak because numerous other variables, including regional banana and beer production, were better predictors of these extinctions. Finally, almost all of our findings were opposite to the predictions of the chytrid-thermal-optimum hypothesis. Although climate change is likely to play an important role in worldwide amphibian declines, more convincing evidence is needed of a causal link. PMID:18987318

  3. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 Animals and Animal... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... diseased flock should be inseminated. If evidence of active disease is noted after insemination is...

  4. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 Animals and Animal... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... diseased flock should be inseminated. If evidence of active disease is noted after insemination is...

  5. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 Animals and Animal... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... diseased flock should be inseminated. If evidence of active disease is noted after insemination is...

  6. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 Animals and Animal... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... diseased flock should be inseminated. If evidence of active disease is noted after insemination is...

  7. 9 CFR 147.27 - Procedures recommended to prevent the spread of disease by artificial insemination of turkeys.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... spread of disease by artificial insemination of turkeys. 147.27 Section 147.27 Animals and Animal... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... diseased flock should be inseminated. If evidence of active disease is noted after insemination is...

  8. New Florida Cattle Identification Program to Protect Florida's Cattle Industry; Mitigate Spread of Disease

    E-print Network

    Hill, Jeffrey E.

    New Florida Cattle Identification Program to Protect Florida's Cattle Industry; Mitigate Spread. In the past, Florida cattle have struggled with animal disease outbreaks, such as Brucellosis and Tuberculosis and those diseases, present in other states, still threaten our cattle today. The Florida Department

  9. The dynamics of sexual contact networks: effects on disease spread and control

    E-print Network

    Cohen, Ted

    are shared between many sexually transmitted infections, the prevalence of these diseases across differentThe dynamics of sexual contact networks: effects on disease spread and control Katy Robinson1, Ted Sexually transmitted pathogens persist in populations despite the availability of biomedical interven tions

  10. The Asian citrus psyllid and the deadly bacterial disease it spreads, Huanglongbing

    E-print Network

    Ishida, Yuko

    The Asian citrus psyllid and the deadly bacterial disease it spreads, Huanglongbing (HLB), threaten citrus trees in backyards and on farms. The psyllid arrived in Southern California in 2008, and HLB disease was first detected in Los Angeles in 2012. All types of citrus--including oranges, grapefruit

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

    PubMed Central

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

    2014-01-01

    Summary 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 greater than that of the focus. Disease control treatments administered shortly after the initial outbreak within the focus may either prevent an epidemic from occurring or reduce its severity. PMID:25512677

  12. The evidence for the airborne spread of Newcastle disease

    PubMed Central

    Hugh-Jones, M.; Allan, W. H.; Dark, F. A.; Harper, G. J.

    1973-01-01

    Newcastle disease virus has been shown to survive when airborne in small particles, both in the laboratory and in the open air. Field outbreaks have been studied and viable virus has been recovered from the open air short distances downwind of infected premises. Vaccination of birds leads to a great reduction in the amount of virus liberated into the air. PMID:4515881

  13. Using the Gravity Model to Estimate the Spatial Spread of Vector-Borne Diseases

    PubMed Central

    Barrios, José Miguel; Verstraeten, Willem W.; Maes, Piet; Aerts, Jean-Marie; Farifteh, Jamshid; Coppin, Pol

    2012-01-01

    The gravity models are commonly used spatial interaction models. They have been widely applied in a large set of domains dealing with interactions amongst spatial entities. The spread of vector-borne diseases is also related to the intensity of interaction between spatial entities, namely, the physical habitat of pathogens’ vectors and/or hosts, and urban areas, thus humans. This study implements the concept behind gravity models in the spatial spread of two vector-borne diseases, nephropathia epidemica and Lyme borreliosis, based on current knowledge on the transmission mechanism of these diseases. Two sources of information on vegetated systems were tested: the CORINE land cover map and MODIS NDVI. The size of vegetated areas near urban centers and a local indicator of occupation-related exposure were found significant predictors of disease risk. Both the land cover map and the space-borne dataset were suited yet not equivalent input sources to locate and measure vegetated areas of importance for disease spread. The overall results point at the compatibility of the gravity model concept and the spatial spread of vector-borne diseases. PMID:23202882

  14. Understanding the mechanism of interferon-induced protection against foot-and-mouth disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) infects cloven-hoofed animals and causes a highly contagious disease that rapidly spreads among many susceptible species. Vaccination with an inactivated whole virus antigen in formulation with adjuvant, or with a replication-defective human adenovirus 5 (Ad5) ab...

  15. Chronic Wasting Disease

    USGS Publications Warehouse

    Richards, Bryan

    2007-01-01

    Chronic wasting disease (CWD) is an always-fatal, neurological illness occurring in North American cervids (members of the deer family), including white-tailed deer, mule deer, elk and moose. Since its discovery in 1967, CWD has spread geographically and increased in prevalence locally. CWD is contagious; it can be transmitted freely within and among free-ranging populations. It is likely that diseased animals can transmit CWD to healthy animals long before they become clinically ill. Managing CWD in free-ranging populations is extremely difficult, therefore preventative measures designed to reduce the chance for disease spread are critically important.

  16. Modeling the spatial spread of infectious diseases: the GLobal Epidemic and Mobility computational model

    PubMed Central

    Balcan, Duygu; Gonçalves, Bruno; Hu, Hao; Ramasco, José J.; Colizza, Vittoria

    2010-01-01

    Here we present the Global Epidemic and Mobility (GLEaM) model that integrates sociodemographic and population mobility data in a spatially structured stochastic disease approach to simulate the spread of epidemics at the worldwide scale. We discuss the flexible structure of the model that is open to the inclusion of different disease structures and local intervention policies. This makes GLEaM suitable for the computational modeling and anticipation of the spatio-temporal patterns of global epidemic spreading, the understanding of historical epidemics, the assessment of the role of human mobility in shaping global epidemics, and the analysis of mitigation and containment scenarios. PMID:21415939

  17. Potential Risk of Regional Disease Spread in West Africa through Cross-Border Cattle Trade

    PubMed Central

    Dean, Anna S.; Fournié, Guillaume; Kulo, Abalo E.; Boukaya, G. Aboudou; Schelling, Esther; Bonfoh, Bassirou

    2013-01-01

    Background Transboundary animal movements facilitate the spread of pathogens across large distances. Cross-border cattle trade is of economic and cultural importance in West Africa. This study explores the potential disease risk resulting from large-scale, cross-border cattle trade between Togo, Burkina Faso, Ghana, Benin, and Nigeria for the first time. Methods and Principal Findings A questionnaire-based survey of livestock movements of 226 cattle traders was conducted in the 9 biggest cattle markets of northern Togo in February-March 2012. More than half of the traders (53.5%) operated in at least one other country. Animal flows were stochastically simulated based on reported movements and the risk of regional disease spread assessed. More than three quarters (79.2%, range: 78.1–80.0%) of cattle flowing into the market system originated from other countries. Through the cattle market system of northern Togo, non-neighbouring countries were connected via potential routes for disease spread. Even for diseases with low transmissibility and low prevalence in a given country, there was a high risk of disease introduction into other countries. Conclusions By stochastically simulating data collected by interviewing cattle traders in northern Togo, this study identifies potential risks for regional disease spread in West Africa through cross-border cattle trade. The findings highlight that surveillance for emerging infectious diseases as well as control activities targeting endemic diseases in West Africa are likely to be ineffective if only conducted at a national level. A regional approach to disease surveillance, prevention and control is essential. PMID:24130721

  18. GIS-Based Epidemiological Modeling of an Emerging Forest Disease: Spread of

    E-print Network

    247 GIS-Based Epidemiological Modeling of an Emerging Forest Disease: Spread of Sudden Oak Death of epidemiological models to realistic landscapes in a GIS can allow for a rigorous validation of model performance applied in a GIS to real-world wildland landscapes. In this paper, we present and evaluate a GIS

  19. Unhealthy herds: indirect effects of predators enhance two drivers of disease spread

    E-print Network

    Hall, Spencer

    host, yeast parasite system to demon- strate such trait-mediated indirect effects. We exposed tenUnhealthy herds: indirect effects of predators enhance two drivers of disease spread Meghan A herds' effect, including a predator-induced change in prey/host traits which enhances susceptibility

  20. The role of wild animals in the spread of exotic diseases in Australia.

    PubMed

    Murray, M D; Snowdon, W A

    1976-12-01

    The distributions of the following feral animals are given -- cattle, buffalo, pig, goat, deer, camel, horse, donkey, fox, dog and cat -- and the native dingo. The possible role these and the native rodents, marsupials and monotremes would play should an exotic disease of livestock enter Australia is discussed. It is considered that feral animals would be important in creating foci from which the disease would spread. PMID:1021109

  1. ENHANCED ANTIVIRAL ACTIVITY AGAINST FOOT-AND-MOUTH DISEASE VIRUS BY A COMBINATION OF TYPE 1 AND 2 PORCINE INTERFERONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) is the most contagious pathogen of cloven-hoofed animals including swine and bovines and it is essential that after an outbreak rapid protection measures are initiated to prevent spread of the disease. Previously, we showed that inoculation of swine with 109 pfu o...

  2. Disease properties, geography, and mitigation strategies in a simulation spread of rinderpest across the United States

    PubMed Central

    2011-01-01

    For the past decade, the Food and Agriculture Organization of the United Nations has been working toward eradicating rinderpest through vaccination and intense surveillance by 2012. Because of the potential severity of a rinderpest epidemic, it is prudent to prepare for an unexpected outbreak in animal populations. There is no immunity to the disease among the livestock or wildlife in the United States (US). If rinderpest were to emerge in the US, the loss in livestock could be devastating. We predict the potential spread of rinderpest using a two-stage model for the spread of a multi-host infectious disease among agricultural animals in the US. The model incorporates large-scale interactions among US counties and the small-scale dynamics of disease spread within a county. The model epidemic was seeded in 16 locations and there was a strong dependence of the overall epidemic size on the starting location. The epidemics were classified according to overall size into small epidemics of 100 to 300 animals (failed epidemics), epidemics infecting 3 000 to 30 000 animals (medium epidemics), and the large epidemics infecting around one million beef cattle. The size of the rinderpest epidemics were directly related to the origin of the disease and whether or not the disease moved into certain key counties in high-livestock-density areas of the US. The epidemic size also depended upon response time and effectiveness of movement controls. PMID:21435236

  3. Catch the wave: prairie dogs assess neighbours' awareness using contagious displays.

    PubMed

    Hare, James F; Campbell, Kevin L; Senkiw, Robert W

    2014-02-22

    The jump-yip display of black-tailed prairie dogs (Cynomys ludovicianus) is contagious, spreading through a prairie dog town as 'the wave' through a stadium. Because contagious communication in primates serves to assess conspecific social awareness, we investigated whether instigators of jump-yip bouts adjusted their behaviour relative to the response of conspecifics recruited to display bouts. Increased responsiveness of neighbouring town members resulted in bout initiators devoting a significantly greater proportion of time to active foraging. Contagious jump-yips thus function to assess neighbours' alertness, soliciting social information to assess effective conspecific group size in real time and reveal active probing of conspecific awareness consistent with theory of mind in these group-living rodents. PMID:24403324

  4. Catch the wave: prairie dogs assess neighbours’ awareness using contagious displays

    PubMed Central

    Hare, James F.; Campbell, Kevin L.; Senkiw, Robert W.

    2014-01-01

    The jump–yip display of black-tailed prairie dogs (Cynomys ludovicianus) is contagious, spreading through a prairie dog town as ‘the wave’ through a stadium. Because contagious communication in primates serves to assess conspecific social awareness, we investigated whether instigators of jump–yip bouts adjusted their behaviour relative to the response of conspecifics recruited to display bouts. Increased responsiveness of neighbouring town members resulted in bout initiators devoting a significantly greater proportion of time to active foraging. Contagious jump–yips thus function to assess neighbours’ alertness, soliciting social information to assess effective conspecific group size in real time and reveal active probing of conspecific awareness consistent with theory of mind in these group-living rodents. PMID:24403324

  5. Disinfection of foot-and-mouth disease and African swine fever viruses with citric acid and sodium hypochlorite on birch wood carriers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transboundary animal disease viruses such as foot-and-mouth disease virus (FMDV) and African swine fever virus (ASFV) are highly contagious and cause severe morbidity and mortality in livestock. Proper disinfection during an outbreak can help prevent virus spread and will shorten the time for contam...

  6. A possible role of crows in the spread of diarrhoeal diseases in Aden.

    PubMed

    al-Sallami, S

    1991-01-01

    The Indian House Crow (Corvus splendens) has increased dramatically in number in Aden. These birds pollute the environment by dropping their faecal material all over the city. They may accordingly be related to important public health problems. The present work aimed at investigating the possibility that they play a role in the spread of diarrheal diseases. One hundred and fifty crows were collected and their liver, intestine and cloaca examined bacteriologically for Enterobacteriaceae and Vibrionaceas as well as for parasites. Different members of Enterobacteriaceae including Salmonella, and Shigella serotypes and Proteus strains as well as members of Vibrionaceae and Pseudomonads were isolated from a great proportion of crows. Some of them were found identical to the strains previously isolated from patients suffering from diarrhea in Aden. Giardia lamblia cysts and Hymenolepis nana ova were also recovered from crows. It was concluded that crows may participate in the spread of diarrheal diseases in Aden. PMID:1791416

  7. Modelling the spread of sexually transmitted diseases on scale-free networks

    NASA Astrophysics Data System (ADS)

    Liu, Mao-Xing; Ruan, Jiong

    2009-06-01

    In this paper a new model for the spread of sexually transmitted diseases (STDs) is presented. The dynamic behaviors of the model on a heterogenous scale-free (SF) network are considered, where the absence of a threshold on the SF network is demonstrated, and the stability of the disease-free equilibrium is obtained. Three immunization strategies, uniform immunization, proportional immunization and targeted immunization, are applied in this model. Analytical and simulated results are given to show that the proportional immunization strategy in the model is effective on SF networks.

  8. Global warming and the potential spread of vector-borne diseases

    SciTech Connect

    Patz, J.

    1996-12-31

    Climatic factors influence many vector-borne infectious diseases, in addition to demographic, biological, and ecological determinants. The United Nation`s Intergovernmental Panel on Climate Change (IPCC) estimates an unprecedented global rise of 2.0 C by the year 2100. Of major concern is that these changes can affect the spread of many serious infectious diseases, including malaria and dengue fever. Global warming would directly affect disease transmission by shifting the mosquito`s geographic range, increasing reproductive and biting rates, and shortening pathogen incubation period. Human migration and damage to health infrastructures from the projected increase in climate variability and sea level rise could indirectly contribute to disease transmission. A review of this literature, as well as preliminary data from ongoing studies will be presented.

  9. Power law approximations of movement network data for modeling infectious disease spread.

    PubMed

    Geilhufe, Marc; Held, Leonhard; Skrøvseth, Stein Olav; Simonsen, Gunnar S; Godtliebsen, Fred

    2014-05-01

    Globalization and increased mobility of individuals enable person-to-person transmitted infectious diseases to spread faster to distant places around the world, making good models for the spread increasingly important. We study the spatiotemporal pattern of spread in the remotely located and sparsely populated region of North Norway in various models with fixed, seasonal, and random effects. The models are applied to influenza A counts using data from positive microbiology laboratory tests as proxy for the underlying disease incidence. Human travel patterns with local air, road, and sea traffic data are incorporated as well as power law approximations thereof, both with quasi-Poisson regression and based on the adjacency structure of the relevant municipalities. We investigate model extensions using information about the proportion of positive laboratory tests, data on immigration from outside North Norway and by connecting population to the movement network. Furthermore, we perform two separate analyses for nonadults and adults as children are an important driver for influenza A. Comparisons of one-step-ahead predictions generally yield better or comparable results using power law approximations. PMID:24843881

  10. Cellular Changes Induced by Adenovirus Vaccine Vectors Expressing Foot-and-Mouth Disease Virus Structural and Nonstructural Proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) is the most contagious pathogen of cloven-hoofed animals including swine and bovines. The emergency control of outbreaks is dependent on rapid protection and prevention of virus spread. Adenovirus-based FMD subunit vaccines containing the coding region of viral ca...

  11. Enhanced Antiviral Activity Against Foot-and-Mouth Disease Virus by the Combination of Bovine Type 1 and 2 Interferons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) is the most contagious pathogen of cloven-hoofed animals including swine and bovines. The emergency control of outbreaks is dependent on rapid protection and prevention of spread of the infection. Human adenovirus type 5 expressing porcine interferon alpha (Ad5-pI...

  12. Social modulation of contagious yawning in wolves.

    PubMed

    Romero, Teresa; Ito, Marie; Saito, Atsuko; Hasegawa, Toshikazu

    2014-01-01

    On the basis of observational and experimental evidence, several authors have proposed that contagious yawn is linked to our capacity for empathy, thus presenting a powerful tool to explore the root of empathy in animal evolution. The evidence for the occurrence of contagious yawning and its link to empathy, however, is meagre outside primates and only recently domestic dogs have demonstrated this ability when exposed to human yawns. Since dogs are unusually skillful at reading human communicative behaviors, it is unclear whether this phenomenon is deeply rooted in the evolutionary history of mammals or evolved de novo in dogs as a result of domestication. Here we show that wolves are capable of yawn contagion, suggesting that such ability is a common ancestral trait shared by other mammalian taxa. Furthermore, the strength of the social bond between the model and the subject positively affected the frequency of contagious yawning, suggesting that in wolves the susceptibility of yawn contagion correlates with the level of emotional proximity. Moreover, female wolves showed a shorter reaction time than males when observing yawns of close associates, suggesting that females are more responsive to their social stimuli. These results are consistent with the claim that the mechanism underlying contagious yawning relates to the capacity for empathy and suggests that basic building blocks of empathy might be present in a wide range of species. PMID:25162677

  13. Social Modulation of Contagious Yawning in Wolves

    PubMed Central

    Romero, Teresa; Ito, Marie; Saito, Atsuko; Hasegawa, Toshikazu

    2014-01-01

    On the basis of observational and experimental evidence, several authors have proposed that contagious yawn is linked to our capacity for empathy, thus presenting a powerful tool to explore the root of empathy in animal evolution. The evidence for the occurrence of contagious yawning and its link to empathy, however, is meagre outside primates and only recently domestic dogs have demonstrated this ability when exposed to human yawns. Since dogs are unusually skilful at reading human communicative behaviors, it is unclear whether this phenomenon is deeply rooted in the evolutionary history of mammals or evolved de novo in dogs as a result of domestication. Here we show that wolves are capable of yawn contagion, suggesting that such ability is a common ancestral trait shared by other mammalian taxa. Furthermore, the strength of the social bond between the model and the subject positively affected the frequency of contagious yawning, suggesting that in wolves the susceptibility of yawn contagion correlates with the level of emotional proximity. Moreover, female wolves showed a shorter reaction time than males when observing yawns of close associates, suggesting that females are more responsive to their social stimuli. These results are consistent with the claim that the mechanism underlying contagious yawning relates to the capacity for empathy and suggests that basic building blocks of empathy might be present in a wide range of species. PMID:25162677

  14. Hitting Is Contagious: Experience and Action Induction

    ERIC Educational Resources Information Center

    Gray, Rob; Beilock, Sian L.

    2011-01-01

    In baseball, it is believed that "hitting is contagious," that is, probability of success increases if the previous few batters get a hit. Could this effect be partially explained by action induction--that is, the tendency to perform an action related to one that has just been observed? A simulation was used to investigate the effect of inducing…

  15. Contagious bovine pleuropneumonia (CBPP) in the Maasai ecosystem of south-western Kenya: Evaluation of seroprevalence, risk factors and vaccine safety and efficacy. 

    E-print Network

    Mtui-Malamsha, Niwael Jesse

    2009-01-01

    Contagious bovine pleuropneumonia (CBPP) is a bovine bacterial disease of major economic importance in sub-Saharan Africa. Vaccination has been recommended to control the disease in endemic areas such as the Maasai ...

  16. Influence on disease spread dynamics of herd characteristics in a structured livestock industry

    PubMed Central

    Lindström, Tom; Lewerin, Susanna Sternberg; Wennergren, Uno

    2012-01-01

    Studies of between-herd contacts may provide important insight to disease transmission dynamics. By comparing the result from models with different levels of detail in the description of animal movement, we studied how factors influence the final epidemic size as well as the dynamic behaviour of an outbreak. We investigated the effect of contact heterogeneity of pig herds in Sweden due to herd size, between-herd distance and production type. Our comparative study suggests that the production-type structure is the most influential factor. Hence, our results imply that production type is the most important factor to obtain valid data for and include when modelling and analysing this system. The study also revealed that all included factors reduce the final epidemic size and also have yet more diverse effects on initial rate of disease spread. This implies that a large set of factors ought to be included to assess relevant predictions when modelling disease spread between herds. Furthermore, our results show that a more detailed model changes predictions regarding the variability in the outbreak dynamics and conclude that this is an important factor to consider in risk assessment. PMID:22112656

  17. A Hybrid Sensitivity Analysis Approach for Agent-based Disease Spread Models

    SciTech Connect

    Pullum, Laura L; Cui, Xiaohui

    2012-01-01

    Agent-based models (ABM) have been widely deployed in different fields for studying the collective behavior of large numbers of interacting agents. Of particular interest lately is the application of agent-based and hybrid models to epidemiology, specifically Agent-based Disease Spread Models (ABDSM). Validation (one aspect of the means to achieve dependability) of ABDSM simulation models is extremely important. It ensures that the right model has been built and lends confidence to the use of that model to inform critical decisions. In this report, we describe our preliminary efforts in ABDSM validation by using hybrid model fusion technology.

  18. Sexually transmitted diseases in Ethiopia. Social factors contributing to their spread and implications for developing countries.

    PubMed

    Plorde, D S

    1981-12-01

    Sexually transmitted diseases in developing countries are causing concern to those responsible for their control and eradication. To gain a better understanding of the problems involved in a country struggling with development, the economic and psychosocial factors influencing the spread of STD in Ethiopia have been studied. Increased migration and urbanisation and the changing role of women have led to a rise in prostitution. Thus changes in the social structure--particularly in relation to the education and employment of women--and improved medical services are essential for the long-term control of STD. PMID:6895708

  19. Genomic insights into a contagious cancer in Tasmanian devils.

    PubMed

    Grueber, Catherine E; Peel, Emma; Gooley, Rebecca; Belov, Katherine

    2015-09-01

    The Tasmanian devil faces extinction due to a contagious cancer. Genetic and genomic technologies revealed that the disease arose in a Schwann cell of a female devil. Instead of dying with the original host, the tumour was passed from animal to animal, slipping under the radar of the immune system. Studying the genomes of the devil and the cancer has driven our understanding of this unique disease. From characterising immune genes and immune responses to studying tumour evolution, we have begun to uncover how a cancer can be 'caught' and are using genomic data to manage an insurance population of disease-free devils for the long-term survival of the species. PMID:26027792

  20. Transmission of chronic wasting disease in Wisconsin white-tailed deer: implications for disease spread and management.

    PubMed

    Jennelle, Christopher S; Henaux, Viviane; Wasserberg, Gideon; Thiagarajan, Bala; Rolley, Robert E; Samuel, Michael D

    2014-01-01

    Few studies have evaluated the rate of infection or mode of transmission for wildlife diseases, and the implications of alternative management strategies. We used hunter harvest data from 2002 to 2013 to investigate chronic wasting disease (CWD) infection rate and transmission modes, and address how alternative management approaches affect disease dynamics in a Wisconsin white-tailed deer population. Uncertainty regarding demographic impacts of CWD on cervid populations, human and domestic animal health concerns, and potential economic consequences underscore the need for strategies to control CWD distribution and prevalence. Using maximum-likelihood methods to evaluate alternative multi-state deterministic models of CWD transmission, harvest data strongly supports a frequency-dependent transmission structure with sex-specific infection rates that are two times higher in males than females. As transmissible spongiform encephalopathies are an important and difficult-to-study class of diseases with major economic and ecological implications, our work supports the hypothesis of frequency-dependent transmission in wild deer at a broad spatial scale and indicates that effective harvest management can be implemented to control CWD prevalence. Specifically, we show that harvest focused on the greater-affected sex (males) can result in stable population dynamics and control of CWD within the next 50 years, given the constraints of the model. We also provide a quantitative estimate of geographic disease spread in southern Wisconsin, validating qualitative assessments that CWD spreads relatively slowly. Given increased discovery and distribution of CWD throughout North America, insights from our study are valuable to management agencies and to the general public concerned about the impacts of CWD on white-tailed deer populations. PMID:24658535

  1. Analytical Modelling of the Spread of Disease in Confined and Crowded Spaces

    PubMed Central

    Goscé, Lara; Barton, David A. W.; Johansson, Anders

    2014-01-01

    Since 1927 and until recently, most models describing the spread of disease have been of compartmental type, based on the assumption that populations are homogeneous and well-mixed. Recent models have utilised agent-based models and complex networks to explicitly study heterogeneous interaction patterns, but this leads to an increasing computational complexity. Compartmental models are appealing because of their simplicity, but their parameters, especially the transmission rate, are complex and depend on a number of factors, which makes it hard to predict how a change of a single environmental, demographic, or epidemiological factor will affect the population. Therefore, in this contribution we propose a middle ground, utilising crowd-behaviour research to improve compartmental models in crowded situations. We show how both the rate of infection as well as the walking speed depend on the local crowd density around an infected individual. The combined effect is that the rate of infection at a population scale has an analytically tractable non-linear dependency on crowd density. We model the spread of a hypothetical disease in a corridor and compare our new model with a typical compartmental model, which highlights the regime in which current models may not produce credible results. PMID:24798322

  2. Weather, host and vector — their interplay in the spread of insect-borne animal virus diseases

    PubMed Central

    Sellers, R. F.

    1980-01-01

    The spread of insect-borne animal virus diseases is influenced by a number of factors. Hosts migrate, move or are conveyed over long distances: vectors are carried on the wind for varying distances in search of hosts and breeding sites; weather and climate affect hosts and vectors through temperature, moisture and wind. As parasites of host and vector, viruses are carried by animals, birds and insects, and their spread can be correlated with the migration of hosts and the carriage of vectors on winds associated with the movements of the Intertropical Convergence Zone (ITCZ) and warm winds to the north and south of the limits of the ITCZ. The virus is often transmitted from a local cycle to a migratory cycle and back again. Examples of insect-borne virus diseases and their spread are analysed. Japanese, Murray Valley, Western equine, Eastern equine and St Louis encephalitis represent viruses transmitted by mosquito—bird or pig cycles. The areas experiencing infection with these viruses can be divided into a number of zones: A, B, C, D, E and F. In zone A there is a continuous cycle of virus in host and vector throughout the year; in zone B, there is an upsurge in the cycle during the wet season, but the cycle continues during the dry season; there is movement of infected vectors between and within zones A and B on the ITCZ and the virus is introduced to zone C by infected vectors on warm winds; persistence may occur in zone C if conditions are right. In zone D, virus is introduced each year by infected vectors on warm winds and the arrival of the virus coincides with the presence of susceptible nestling birds and susceptible piglets. The disappearance of virus occurs at the time when migrating mosquitoes and birds are returning to warmer climates. The virus is introduced to zone E only on occasions every 5-10 years when conditions are suitable. Infected hosts introduced to zone F do not lead to circulation of virus, since the climate is unsuitable for vectors. Zones A, B and C correspond to endemic and zones D and E to epidemic conditions. Similar zones can be recognized for African horse sickness, bluetongue, Ibaraki disease and bovine ephemeral fever — examples of diseases transmitted in a midge-mammal cycle. In zones A and B viruses are transported by infected midges carried on the wind in association with the movement of ITCZ and undergo cycles in young animals. In these zones and in zone C there is a continual movement of midges on the warm wind between one area and another, colonizing new sites or reinforcing populations of midges already present. Virus is introduced at times into fringe areas (zones D and E) and, as there is little resistance in the host, gives rise to clinical signs of disease. In some areas there is persistence during adverse conditions; in others, the virus is carried back to the endemic zones by infected midges or vectors. Examples of viruses maintained in a mosquito/biting fly—mammal cycle are Venezuelan equine encephalitis and vesicular stomatitis. These viruses enter a migratory cycle from a local cycle and the vectors in the migratory cycle are carried over long distances on the wind. Further examples of virus spread by movement of vectors include West Nile, Rift Valley fever, yellow fever, epizootic haemorrhagic disease of deer and Akabane viruses. In devising means of control it is essential to decide the relationship of host, vector and virus and the nature of the zone in which the area to be controlled lies. Because of the continual risk of reintroduction of infected vectors, it is preferable to protect the host by dipping, spraying or by vaccination rather than attempting to eliminate the local population of insects. PMID:6131919

  3. A delay mathematical model for the spread and control of water borne diseases.

    PubMed

    Misra, A K; Singh, Vishal

    2012-05-21

    A non-linear SIRS mathematical model to explore the dynamics of water borne diseases like cholera is proposed and analyzed by incorporating delay in using disinfectants to control the disease. It is assumed that the only way for the spread of infection is ingestion of contaminated water by susceptibles. As the pathogens discharged by infectives reach to the aquatic environment, it is assumed that the growth rate of pathogens is proportional to the number of infectives. Further, it is assumed that disinfectants are introduced to kill pathogens with a rate proportional to the density of pathogens in the aquatic environment. The model is analyzed by using stability theory of delay differential equations. It is found that the model exhibits two equilibria, the disease free equilibrium and the endemic equilibrium. The analysis shows that under certain conditions, the cholera disease may be controlled by using disinfectants but a longer delay in their use may destabilize the system. Numerical simulation is also carried out to confirm the analytical results. PMID:22586723

  4. Predictive modelling of contagious deforestation in the Brazilian Amazon.

    PubMed

    Rosa, Isabel M D; Purves, Drew; Souza, Carlos; Ewers, Robert M

    2013-01-01

    Tropical forests are diminishing in extent due primarily to the rapid expansion of agriculture, but the future magnitude and geographical distribution of future tropical deforestation is uncertain. Here, we introduce a dynamic and spatially-explicit model of deforestation that predicts the potential magnitude and spatial pattern of Amazon deforestation. Our model differs from previous models in three ways: (1) it is probabilistic and quantifies uncertainty around predictions and parameters; (2) the overall deforestation rate emerges "bottom up", as the sum of local-scale deforestation driven by local processes; and (3) deforestation is contagious, such that local deforestation rate increases through time if adjacent locations are deforested. For the scenarios evaluated-pre- and post-PPCDAM ("Plano de Ação para Proteção e Controle do Desmatamento na Amazônia")-the parameter estimates confirmed that forests near roads and already deforested areas are significantly more likely to be deforested in the near future and less likely in protected areas. Validation tests showed that our model correctly predicted the magnitude and spatial pattern of deforestation that accumulates over time, but that there is very high uncertainty surrounding the exact sequence in which pixels are deforested. The model predicts that under pre-PPCDAM (assuming no change in parameter values due to, for example, changes in government policy), annual deforestation rates would halve between 2050 compared to 2002, although this partly reflects reliance on a static map of the road network. Consistent with other models, under the pre-PPCDAM scenario, states in the south and east of the Brazilian Amazon have a high predicted probability of losing nearly all forest outside of protected areas by 2050. This pattern is less strong in the post-PPCDAM scenario. Contagious spread along roads and through areas lacking formal protection could allow deforestation to reach the core, which is currently experiencing low deforestation rates due to its isolation. PMID:24204776

  5. Predictive Modelling of Contagious Deforestation in the Brazilian Amazon

    PubMed Central

    Rosa, Isabel M. D.; Purves, Drew; Souza, Carlos; Ewers, Robert M.

    2013-01-01

    Tropical forests are diminishing in extent due primarily to the rapid expansion of agriculture, but the future magnitude and geographical distribution of future tropical deforestation is uncertain. Here, we introduce a dynamic and spatially-explicit model of deforestation that predicts the potential magnitude and spatial pattern of Amazon deforestation. Our model differs from previous models in three ways: (1) it is probabilistic and quantifies uncertainty around predictions and parameters; (2) the overall deforestation rate emerges “bottom up”, as the sum of local-scale deforestation driven by local processes; and (3) deforestation is contagious, such that local deforestation rate increases through time if adjacent locations are deforested. For the scenarios evaluated–pre- and post-PPCDAM (“Plano de Ação para Proteção e Controle do Desmatamento na Amazônia”)–the parameter estimates confirmed that forests near roads and already deforested areas are significantly more likely to be deforested in the near future and less likely in protected areas. Validation tests showed that our model correctly predicted the magnitude and spatial pattern of deforestation that accumulates over time, but that there is very high uncertainty surrounding the exact sequence in which pixels are deforested. The model predicts that under pre-PPCDAM (assuming no change in parameter values due to, for example, changes in government policy), annual deforestation rates would halve between 2050 compared to 2002, although this partly reflects reliance on a static map of the road network. Consistent with other models, under the pre-PPCDAM scenario, states in the south and east of the Brazilian Amazon have a high predicted probability of losing nearly all forest outside of protected areas by 2050. This pattern is less strong in the post-PPCDAM scenario. Contagious spread along roads and through areas lacking formal protection could allow deforestation to reach the core, which is currently experiencing low deforestation rates due to its isolation. PMID:24204776

  6. Critical parameters for modelling the spread of foot-and-mouth disease in wildlife.

    PubMed

    Highfield, L D; Ward, M P; Laffan, S W; Norby, B; Wagner, G G

    2010-01-01

    A series of simulation experiments was conducted to determine how estimates of the latent and infectious periods, number of neighbours (contacts) and population size impact on the predicted magnitude and distribution of foot-and-mouth disease (FMD) outbreaks in white-tailed deer in southern Texas. Outbreaks were simulated using a previously developed and applied susceptible-latent-infected-recovered geographic automata model. There were substantial differences in the estimated predicted number of deer and locations infected, based on the model parameters used (3779-119 879 deer infected and 227-6526 locations affected). There were also substantial differences in the spatial risk of infection based on the model parameters used. The predicted spread of FMD was found to be most sensitive to the assumed latent period and the assumed number of contacts. How these parameters are estimated is likely to be critical in studies on the impact of FMD spread in situations in which wildlife reservoirs might potentially exist. PMID:19480725

  7. Epidemic predictions in an imperfect world: modelling disease spread with partial data.

    PubMed

    Dawson, Peter M; Werkman, Marleen; Brooks-Pollock, Ellen; Tildesley, Michael J

    2015-06-01

    'Big-data' epidemic models are being increasingly used to influence government policy to help with control and eradication of infectious diseases. In the case of livestock, detailed movement records have been used to parametrize realistic transmission models. While livestock movement data are readily available in the UK and other countries in the EU, in many countries around the world, such detailed data are not available. By using a comprehensive database of the UK cattle trade network, we implement various sampling strategies to determine the quantity of network data required to give accurate epidemiological predictions. It is found that by targeting nodes with the highest number of movements, accurate predictions on the size and spatial spread of epidemics can be made. This work has implications for countries such as the USA, where access to data is limited, and developing countries that may lack the resources to collect a full dataset on livestock movements. PMID:25948687

  8. Epidemic predictions in an imperfect world: modelling disease spread with partial data

    PubMed Central

    Dawson, Peter M.; Werkman, Marleen; Brooks-Pollock, Ellen; Tildesley, Michael J.

    2015-01-01

    ‘Big-data’ epidemic models are being increasingly used to influence government policy to help with control and eradication of infectious diseases. In the case of livestock, detailed movement records have been used to parametrize realistic transmission models. While livestock movement data are readily available in the UK and other countries in the EU, in many countries around the world, such detailed data are not available. By using a comprehensive database of the UK cattle trade network, we implement various sampling strategies to determine the quantity of network data required to give accurate epidemiological predictions. It is found that by targeting nodes with the highest number of movements, accurate predictions on the size and spatial spread of epidemics can be made. This work has implications for countries such as the USA, where access to data is limited, and developing countries that may lack the resources to collect a full dataset on livestock movements. PMID:25948687

  9. Hybridization and the Origin of Contagious Asexuality in Daphnia pulex.

    PubMed

    Xu, Sen; Spitze, Ken; Ackerman, Matthew S; Ye, Zhiqiang; Bright, Lydia; Keith, Nathan; Jackson, Craig E; Shaw, Joseph R; Lynch, Michael

    2015-12-01

    Hybridization plays a potentially important role in the origin of obligate parthenogenesis (OP) in many organisms. However, it remains controversial whether hybridization directly triggers the transition from sexual reproduction to obligate asexuality or a hybrid genetic background enables asexual species to persist. Furthermore, we know little about the specific genetic elements from the divergent, yet still hybridizing lineages responsible for this transition and how these elements are further spread to create other OP lineages. In this study, we address these questions in Daphnia pulex, where cyclically parthenogenetic (CP) and OP lineages coexist. Ancestry estimates and whole-genome association mapping using 32 OP isolates suggest that a complex hybridization history between the parental species D. pulex and D. pulicaria is responsible for the introgression of a set of 647 D. pulicaria single nucleotide polymorphism alleles that show perfect association with OP. Crossing experiments using males of OP lineages and females of CP lineages strongly support a polygenic basis for OP. Single-sperm analyses show that although normal meiotic recombination occurs in the production of haploid sperm by males of OP lineages, a significant proportion of such sperm are polyploid, suggesting that the spread of asexual elements through these males (i.e., contagious asexuality) is much less efficient than previously envisioned. Although the current Daphnia genome annotation does not provide mechanistic insight into the nature of the asexuality-associated alleles, these alleles should be considered as candidates for future investigations on the genetic underpinnings of OP. PMID:26351296

  10. Controlling wildlife fungal disease spread: in vitro efficacy of disinfectants against Batrachochytrium dendrobatidis and Mucor amphibiorum.

    PubMed

    Webb, Rebecca; Philips, Annie; Speare, Rick; Connolly, Joanne; Berger, Lee

    2012-06-13

    Chytridiomycosis in amphibians, and mucormycosis in the platypus Ornithorhynchus anatinus and amphibians, are serious fungal diseases affecting these aquatic taxa. In Tasmania, Australia, the fungi that cause these diseases overlap in range along with Phytophthora cinnamomi (Pc), an invasive fungal plant pathogen. To identify disinfectants that may be useful to reduce anthropogenic spread of these fungi to uninfected wilderness areas, for example by bush walkers and forestry or fire-fighting operations, we tested 3 disinfectants and a fire-fighting foam against Mucor amphibiorum (Ma) and tested 1 disinfectant and the foam against Batrachochytrium dendrobatidis (Bd). Combining the present study with previous work we found Bd was more susceptible to all 4 chemicals than Ma. Phytoclean, a disinfectant used at 2 to 10% for 30 s to control Pc, killed cultures of Bd at 0.075% and Ma at 5%, when also applied for 30 s. The disinfectant F10sc was not effective against Ma at standard exposures, but previous work shows Bd is killed at 0.03% with a 1 min exposure. Path-X is effective against Bd at 0.001% with a 30 s exposure and killed Ma at 1% with a 5 min exposure. Forexpan S, a foam added to water at 0.1 to 1% to control forest fires, killed Bd but not Ma when used at 1% for 2 min. Therefore, Phytoclean and Path-X have broader efficacy, although Path-X has not been trialled against Pc. Interestingly a positive mating strain of Ma (from a platypus) was more resistant to disinfectants than a negative strain (from a frog). Current protocols against Pc that involve high concentrations (10%) of Phytoclean are likely to reduce spread of pathogenic wildlife fungi, which is important for protecting biodiversity. PMID:22691980

  11. Avian influenza shedding patterns in waterfowl: implications for surveillance, environmentaltransmission, and disease spread

    USGS Publications Warehouse

    Henaux, V.; Samuel, M.D.

    2011-01-01

    Despite the recognized importance of fecal/oral transmission of low pathogenic avian influenza (LPAI) via contaminated wetlands, little is known about the length, quantity, or route of AI virus shed by wild waterfowl. We used published laboratory challenge studies to evaluate the length and quantity of low pathogenic (LP) and highly pathogenic (HP) virus shed via oral and cloacal routes by AI-infected ducks and geese, and how these factors might influence AI epidemiology and virus detection. We used survival analysis to estimate the duration of infection(from virus inoculation to the last day virus was shed) and nonlinear models to evaluate temporal patterns in virus shedding. We found higher mean virus titer and longer median infectious period for LPAI-infected ducks (1011.5 days in oral and cloacal swabs) than HPAI-infected ducks(5 days) and geese (7.5 days). Based on the median bird infectious dose, we found that environmental contamination is two times higher for LPAI- than HPAI-infectious ducks, which implies that susceptible birds may have a higher probability of infection during LPAI than HP AIoutbreaks. Less environmental contamination during the course of infection and previously documented shorter environmental persistence for HPAI than LPAI suggest that the environment is a less favorable reservoir for HPAI. The longer infectious period, higher virus titers, and subclinical infections with LPAI viruses favor the spread of these viruses by migratory birds in comparison to HPAI. Given the lack of detection of HPAI viruses through worldwide surveillance,we suggest monitoring for AI should aim at improving our understanding of AI dynamics (inparticular, the role of the environment and immunity) using long-term comprehensive live bird, serologic, and environmental sampling at targeted areas. Our findings on LPAI and HPAIshedding patterns over time provide essential information to parameterize environmental transmission and virus spread in predictive epizootio logic models of disease risks. ?? Wildlife Disease Association 2011.

  12. Homogenization, sex, and differential motility predict spread of chronic wasting disease in mule deer in southern Utah.

    PubMed

    Garlick, Martha J; Powell, James A; Hooten, Mevin B; MacFarlane, Leslie R

    2014-08-01

    Chronic wasting disease (CWD) is an infectious prion disease that affects mule deer, along with other Cervids. It is a slow-developing, fatal disease which is rare in the free-ranging deer population of Utah. We present a sex-structured, spatial model for the spread of CWD over heterogeneous landscapes, incorporating both horizontal and environmental transmission pathways. To connect the local movement of deer to the regional spread of CWD, we use ecological diffusion with motility coefficients estimated from mule deer movement data. Ecological diffusion allows for aggregation of populations in desirable habitats and therefore allows for an interaction between density dependent disease transmission and landscape structure. The major innovation presented is use of homogenization to accelerate simulations of disease spread in southeastern Utah, from the La Sal Mountains near Moab to the Abajo Mountains near Monticello. The homogenized model provides accuracy while maintaining fidelity to small-scale habitat effects on deer distribution, including differential aggregation in land cover types with high residence times, with errors comparable to the order parameter measuring separation of small and large scales ([Formula: see text] in this case). We use the averaged coefficients from the homogenized model to explore asymptotic invasion speed and the impact of current population size on disease spread in southeastern Utah. PMID:23846241

  13. Prion-like propagation of mutant SOD1 misfolding and motor neuron disease spread along neuroanatomical pathways.

    PubMed

    Ayers, Jacob I; Fromholt, Susan E; O'Neal, Veronica M; Diamond, Jeffrey H; Borchelt, David R

    2016-01-01

    A hallmark feature of amyotrophic lateral sclerosis (ALS) is that symptoms appear to spread along neuroanatomical pathways to engulf the motor nervous system, suggesting a propagative toxic entity could be involved in disease pathogenesis. Evidence for such a propagative entity emerged recently in studies using mice that express G85R-SOD1 mutant protein fused to YFP (G85R-SOD1:YFP). Heterozygous G85R-SOD1:YFP transgenic mice do not develop ALS symptoms out to 20 months of age. However, when newborns are injected with spinal homogenates from paralyzed mutant SOD1 mice, the G85R-SOD1:YFP mice develop paralysis as early as 6 months of age. We now demonstrate that injecting spinal homogenates from paralyzed mutant SOD1 mice into the sciatic nerves of adult G85R-SOD1:YFP mice produces a spreading motor neuron disease within 3.0 ± 0.2 months of injection. The formation of G85R-SOD1:YFP inclusion pathology spreads slowly in this model system; first appearing in the ipsilateral DRG, then lumbar spinal cord, before spreading rostrally up to the cervical cord by the time mice develop paralysis. Reactive astrogliosis mirrors the spread of inclusion pathology and motor neuron loss is most severe in lumbar cord. G85R-SOD1:YFP inclusion pathology quickly spreads to discrete neurons in the brainstem and midbrain that are synaptically connected to spinal neurons, suggesting a trans-synaptic propagation of misfolded protein. Taken together, the data presented here describe the first animal model that recapitulates the spreading phenotype observed in patients with ALS, and implicates the propagation of misfolded protein as a potential mechanism for the spreading of motor neuron disease. PMID:26650262

  14. Information Regarding MENINGOCOCCAL DISEASE

    E-print Network

    Information Regarding MENINGOCOCCAL DISEASE Student Name. Meningococcal disease is a serious disease, caused by bacteria. Meningococcal disease is a contagious. Meningococcal disease can also cause blood infections. About 2,600 people get meningococcal disease each year

  15. Birth and death of links control disease spreading in empirical contact networks

    NASA Astrophysics Data System (ADS)

    Holme, Petter; Liljeros, Fredrik

    2014-05-01

    We investigate what structural aspects of a collection of twelve empirical temporal networks of human contacts are important to disease spreading. We scan the entire parameter spaces of the two canonical models of infectious disease epidemiology--the Susceptible-Infectious-Susceptible (SIS) and Susceptible-Infectious-Removed (SIR) models. The results from these simulations are compared to reference data where we eliminate structures in the interevent intervals, the time to the first contact in the data, or the time from the last contact to the end of the sampling. The picture we find is that the birth and death of links, and the total number of contacts over a link, are essential to predict outbreaks. On the other hand, the exact times of contacts between the beginning and end, or the interevent interval distribution, do not matter much. In other words, a simplified picture of these empirical data sets that suffices for epidemiological purposes is that links are born, is active with some intensity, and die.

  16. Pharmacodynamics of Antimicrobials against Mycoplasma mycoides mycoides Small Colony, the Causative Agent of Contagious Bovine Pleuropneumonia

    PubMed Central

    Mitchell, John D.; McKellar, Quintin A.; McKeever, Declan J.

    2012-01-01

    Background Mycoplasma mycoides subspecies mycoides Small Colony (MmmSC) is the causative agent of Contagious Bovine Pleuropneumonia (CBPP), a disease of substantial economic importance in sub-Saharan Africa. Failure of vaccination to curtail spread of this disease has led to calls for evaluation of the role of antimicrobials in CBPP control. Three major classes of antimicrobial are effective against mycoplasmas, namely tetracyclines, fluoroquinolones and macrolides. Therefore, the objectives of this study were to determine the effector kinetics of oxytetracycline, danofloxacin and tulathromycin against two MmmSC field strains in artificial medium and adult bovine serum. Methods Minimum inhibitory concentrations (MIC) were determined for oxytetracycline, danofloxacin and tulathromycin against MmmSC strains B237 and Tan8 using a macrodilution technique, and time-kill curves were constructed for various multiples of the MIC over a 24 hour period in artificial medium and serum. Data were fitted to sigmoid Emax models to obtain 24 hour-area under curve/MIC ratios for mycoplasmastasis and, where appropriate, for mycoplasmacidal activity and virtual mycoplasmal elimination. Results Minimum inhibitory concentrations against B237 were 20-fold higher, 2-fold higher and approximately 330-fold lower in serum than in artificial medium for oxytetracycline, danofloxacin and tulathromycin, respectively. Such differences were mirrored in experiments using Tan8. Oxytetracycline was mycoplasmastatic against both strains in both matrices. Danofloxacin elicited mycoplasmacidal activity against B237 and virtual elimination of Tan8; similar maximum antimycoplasmal effects were observed in artificial medium and serum. Tulathromycin effected virtual elimination of B237 but was mycoplasmastatic against Tan8 in artificial medium. However, this drug was mycoplasmastatic against both strains in the more physiologically relevant matrix of serum. Conclusions Oxytetracycline, danofloxacin and tulathromycin are all suitable candidates for further investigation as potential treatments for CBPP. This study also highlights the importance of testing drug activity in biological matrices as well as artificial media. PMID:22952911

  17. Climate Change, Extreme Weather Events, and Fungal Disease Emergence and Spread

    NASA Technical Reports Server (NTRS)

    Tucker, Compton J.; Yager, Karina; Anyamba, Assaf; Linthicum, Kenneth J.

    2011-01-01

    Empirical evidence from multiple sources show the Earth has been warming since the late 19th century. More recently, evidence for this warming trend is strongly supported by satellite data since the late 1970s from the cryosphere, atmosphere, oceans, and land that confirms increasing temperature trends and their consequences (e.g., reduced Arctic sea ice, rising sea level, ice sheet mass loss, etc.). At the same time, satellite observations of the Sun show remarkably stable solar cycles since the late 1970s, when direct observations of the Sun's total solar irradiance began. Numerical simulation models, driven in part by assimilated satellite data, suggest that future-warming trends will lead to not only a warmer planet, but also a wetter and drier climate depending upon location in a fashion consistent with large-scale atmospheric processes. Continued global warming poses new opportunities for the emergence and spread of fungal disease, as climate systems change at regional and global scales, and as animal and plant species move into new niches. Our contribution to this proceedings is organized thus: First, we review empirical evidence for a warming Earth. Second, we show the Sun is not responsible for the observed warming. Third, we review numerical simulation modeling results that project these trends into the future, describing the projected abiotic environment of our planet in the next 40 to 50 years. Fourth, we illustrate how Rift Valley fever outbreaks have been linked to climate, enabling a better understanding of the dynamics of these diseases, and how this has led to the development of an operational predictive outbreak model for this disease in Africa. Fifth, We project how this experience may be applicable to predicting outbreaks of fungal pathogens in a warming world. Lastly, we describe an example of changing species ranges due to climate change, resulting from recent warming in the Andes and associated glacier melt that has enabled amphibians to colonize higher elevation lakes, only to be followed shortly by the emergence of fungal disease in the new habitats.

  18. The Effects of Media Reports on Disease Spread and Important Public Health Measurements.

    PubMed

    Collinson, Shannon; Khan, Kamran; Heffernan, Jane M

    2015-01-01

    Controlling the spread of influenza to reduce the effects of infection on a population is an important mandate of public health. Mass media reports on an epidemic or pandemic can provide important information to the public, and in turn, can induce positive healthy behaviour practices (i.e., handwashing, social distancing) in the individuals, that will reduce the probability of contracting the disease. Mass media fatigue, however, can dampen these effects. Mathematical models can be used to study the effects of mass media reports on epidemic/pandemic outcomes. In this study we employ a stochastic agent based model to provide a quantification of mass media reports on the variability in important public health measurements. We also include mass media report data compiled by the Global Public Health Intelligence Network, to study the effects of mass media reports in the 2009 H1N1 pandemic. We find that the report rate and the rate at which individuals relax their healthy behaviours (media fatigue) greatly affect the variability in important public health measurements. When the mass media reporting data is included in the model, two peaks of infection result. PMID:26528909

  19. The Effects of Media Reports on Disease Spread and Important Public Health Measurements

    PubMed Central

    Collinson, Shannon; Khan, Kamran; Heffernan, Jane M.

    2015-01-01

    Controlling the spread of influenza to reduce the effects of infection on a population is an important mandate of public health. Mass media reports on an epidemic or pandemic can provide important information to the public, and in turn, can induce positive healthy behaviour practices (i.e., handwashing, social distancing) in the individuals, that will reduce the probability of contracting the disease. Mass media fatigue, however, can dampen these effects. Mathematical models can be used to study the effects of mass media reports on epidemic/pandemic outcomes. In this study we employ a stochastic agent based model to provide a quantification of mass media reports on the variability in important public health measurements. We also include mass media report data compiled by the Global Public Health Intelligence Network, to study the effects of mass media reports in the 2009 H1N1 pandemic. We find that the report rate and the rate at which individuals relax their healthy behaviours (media fatigue) greatly affect the variability in important public health measurements. When the mass media reporting data is included in the model, two peaks of infection result. PMID:26528909

  20. Abattoir surveillance demonstrates contagious bovine pleuropneumonia is widespread in Tanzania.

    PubMed

    Noah, Elly Yesse; Kimera, Sharazuli Iddi; Kusiluka, Lughano Jeremy Moses; Wambura, Philemon

    2015-12-01

    A study was conducted to investigate the presence of contagious bovine pleuropneumonia (CBPP) in the slaughter facilities in 10 regions of Tanzania that reported pathological lesions suggestive of CBPP during meat inspection. The aim was to ascertain if slaughter facilities can be used to monitor the occurrence and spread of CBPP in the country. The study involved a questionnaire survey, clinical examination of animals for CBPP symptoms prior to slaughter and postmortem examination of the respiratory system in slaughtered cattle. A total of 12 slaughterhouses and 31 animal markets were involved in the study. A total of 2736 cattle were slaughtered comprising 1978 and 758 in slaughterhouses and animal markets, respectively. Of the total slaughtered stock, 351 of 2736 (12.8 %) had lesions suggestive of CBPP and of these, 236 (8.6 %) were from slaughterhouses and 115 (4.2 %) from animal markets. Acute CBPP cases were observed in 192 of the 236 (81.4 %) and 71 of the 115 (61.7 %) of the animals inspected in the slaughterhouses and markets, respectively. Chronic cases were encountered in 24 (10.2 %) of the animals slaughtered in the slaughterhouses and 19 (16.5 %) at animal markets. This work has confirmed that targeted monitoring for CBPP lesions through meat inspection can be a useful tool for CBPP surveillance in endemic countries like Tanzania. PMID:26315150

  1. The potential role of wildlife in the spread and control of foot and mouth disease in an extensive livestock management system 

    E-print Network

    Highfield, Linda

    2009-05-15

    response and control policy with information on the potential spread of a foreign animal disease incursion with a likely wildlife reservoir. Use of such a decision-support system would enhance the disease incursion preparedness and response capacity...

  2. Modeling the Effect of Herd Immunity and Contagiousness in Mitigating a Smallpox Outbreak.

    PubMed

    Graeden, Ellie; Fielding, Russel; Steinhouse, Kyle E; Rubin, Ilan N

    2015-07-01

    The smallpox antiviral tecovirimat has recently been purchased by the U.S. Strategic National Stockpile. Given significant uncertainty regarding both the contagiousness of smallpox in a contemporary outbreak and the efficiency of a mass vaccination campaign, vaccine prophylaxis alone may be unable to control a smallpox outbreak following a bioterror attack. Here, we present the results of a compartmental epidemiological model that identifies conditions under which tecovirimat is required to curtail the epidemic by exploring how the interaction between contagiousness and prophylaxis coverage of the affected population affects the ability of the public health response to control a large-scale smallpox outbreak. Each parameter value in the model is based on published empirical data. We describe contagiousness parametrically using a novel method of distributing an assumed R-value over the disease course based on the relative rates of daily viral shedding from human and animal studies of cognate orthopoxvirus infections. Our results suggest that vaccination prophylaxis is sufficient to control the outbreak when caused either by a minimally contagious virus or when a very high percentage of the population receives prophylaxis. As vaccination coverage of the affected population decreases below 70%, vaccine prophylaxis alone is progressively less capable of controlling outbreaks, even those caused by a less contagious virus (R0 less than 4). In these scenarios, tecovirimat treatment is required to control the outbreak (total number of cases under an order of magnitude more than the number of initial infections). The first study to determine the relative importance of smallpox prophylaxis and treatment under a range of highly uncertain epidemiological parameters, this work provides public health decision-makers with an evidence-based guide for responding to a large-scale smallpox outbreak. PMID:25480757

  3. Laboratory generation of new parthenogenetic lineages supports contagious parthenogenesis in Artemia

    PubMed Central

    Amat, Francisco; Hontoria, Francisco; Gómez, Africa

    2014-01-01

    Contagious parthenogenesis—a process involving rare functional males produced by a parthenogenetic lineage which mate with coexisting sexual females resulting in fertile parthenogenetic offspring—is one of the most striking mechanisms responsible for the generation of new parthenogenetic lineages. Populations of the parthenogenetic diploid brine shrimp Artemia produce fully functional males in low proportions. The evolutionary role of these so-called Artemia rare males is, however, unknown. Here we investigate whether new parthenogenetic clones could be obtained in the laboratory by mating these rare males with sexual females. We assessed the survival and sex ratio of the hybrid ovoviviparous offspring from previous crosses between rare males and females from all Asiatic sexual species, carried out cross-mating experiments between F1 hybrid individuals to assess their fertility, and estimated the viability and the reproductive mode of the resulting F2 offspring. Molecular analysis confirmed the parentage of hybrid parthenogenetic F2. Our study documents the first laboratory synthesis of new parthenogenetic lineages in Artemia and supports a model for the contagious spread of parthenogenesis. Our results suggest recessive inheritance but further experiments are required to confirm the likelihood of the contagious parthenogenesis model. PMID:25024909

  4. Individual variation in contagious yawning susceptibility is highly stable and largely unexplained by empathy or other known factors.

    PubMed

    Bartholomew, Alex J; Cirulli, Elizabeth T

    2014-01-01

    The contagious aspect of yawning is a well-known phenomenon that exhibits variation in the human population. Despite the observed variation, few studies have addressed its intra-individual reliability or the factors modulating differences in the susceptibility of healthy volunteers. Due to its obvious biological basis and impairment in diseases like autism and schizophrenia, a better understanding of this trait could lead to novel insights into these conditions and the general biological functioning of humans. We administered 328 participants a 3-minute yawning video stimulus, a cognitive battery, and a comprehensive questionnaire that included measures of empathy, emotional contagion, circadian energy rhythms, and sleepiness. Individual contagious yawning measurements were found to be highly stable across testing sessions, both in a lab setting and if administered remotely online, confirming that certain healthy individuals are less susceptible to contagious yawns than are others. Additionally, most individuals who failed to contagiously yawn in our study were not simply suppressing their reaction, as they reported not even feeling like yawning in response to the stimulus. In contrast to previous studies indicating that empathy, time of day, or intelligence may influence contagious yawning susceptibility, we found no influence of these variables once accounting for the age of the participant. Participants were less likely to show contagious yawning as their age increased, even when restricting to ages of less than 40 years. However, age was only able to explain 8% of the variability in the contagious yawn response. The vast majority of the variability in this extremely stable trait remained unexplained, suggesting that studies of its inheritance are warranted. PMID:24632594

  5. Coupling multi-agent model and GIS to simulate pine wood nematode disease spread in ZheJiang Province, China

    NASA Astrophysics Data System (ADS)

    Huang, Huaguo; Wang, Lei; Zhang, XiaoLi; Luo, YouQing; Zhao, Liqiong

    2008-10-01

    A coupled method based on multi-agent model, remote sensing and GIS is described to simulate the forest disease spread. The coupled model focuses on the temporal dynamics of the Bursaphelenchus xylophilus population at the landscape scale. Each individual is modeled as an autonomous agent who behaves according to a set of rules including spreading in the landscape, feeding on Pinus massoniana, sheltering in forest edges and dying, constrained by terrain, land cover and other variables. The model parameters are derived from remote sensing data and field measurements. Ten factors, including damage degree of Pinus Massoniana, altitude and slope, are helped to build the transfer rules. The main outputs are the dynamic disease distribution maps and survived pine population. Our method is applied and validated in DingHai distinct, Zhou Shan city of Zhejiang Province. Three Landsat TM images from the year 1991 to 2006 are used for the pine information extraction. The extracted pine distribution map is used to compare with the simulated surviving pine map. The results show that the coupled model can produce reasonable results and be used as a virtual experiment tool. However, it is difficult to simulate the human activities to help or prevent disease spread and the long fly behavior of insect vectors. Therefore, there still exists some difference between the simulated results and the real data. At the next step, those factors will be considered.

  6. Be-CoDiS: An epidemiological model to predict the risk of human diseases spread worldwide. Application to the 2014 Ebola Virus Disease epidemic

    E-print Network

    Benjamin, Ivorra; Diène, Ngom

    2014-01-01

    Ebola virus disease is a lethal human and primate disease that currently requires a particular attention from the national and international health authorities due to important outbreaks concurring in some Western African countries and possible spread to other continents, which has already occurred in the USA and Spain. Regarding the emergency of this situation, there is a need of development of decision tools to help the authorities to focus their efforts in important factors that can help to eradicate Ebola. Mathematical modeling and, more precisely, epidemiological modeling can help to predict the possible evolution of the Ebola outbreaks and to give some recommendations in the region to be prioritized for surveillance. In this work, we present a first formulation of a new spatial-temporal epidemiological model, called Be-CoDiS (Between-COuntries Disease Spread), based on the combination of a deterministic Individual-Based model (modelling the interaction between countries, considered as individual) for be...

  7. Active surveillance of the aquatic environment for potential prediction, prevention and spread of water borne disease: the cholera paradigm

    NASA Astrophysics Data System (ADS)

    Huq, A.; Colwell, R.

    2011-12-01

    Based on results of ecological and epidemiological studies, occurrence and spread of certain diseases are more fully understood. Cholera is a major waterborne disease, that is relatively easily treatable and clearly preventable, yet tens of thousands die each year worldwide. A dose dependent disease, the infectious dose can vary from 103-106, depending on health status of the victim. Historically, cholera has been shown to spread from person to person. Furthermore, the disease is caused predominantly via ingestion of contaminated water and most of the outbreaks that have been recorded worldwide originated in a coastal region. Using appropriate detection methods, Vibrio cholerae can be isolated from samples collected from ponds, rivers, estuaries, and coastal waters globally. The populations of V. cholerae may vary in numbers during different seasons of the year. It is important to have a clear understanding of the distribution of the causative agent in the environment as such information can assist public health officials in taking action to prevent outbreaks of cholera. Thus an effective monitoring program is critical, particularly in light of climate change with temperature extremes more likely to be occurring. Based on a predictive model and results of ground truth data, temperature has been found to be a factor in the increase of V. cholerae in the environment. Correlation was observed with occurrence of cholera and both temperature and salinity. More recent research indicates additional factors need to be considered in predicting cholera epidemics, including the hydrology and disease dynamics.

  8. A tale of two tumours: comparison of the immune escape strategies of contagious cancers.

    PubMed

    Siddle, Hannah V; Kaufman, Jim

    2013-09-01

    The adaptive immune system should prevent cancer cells passing from one individual to another, in much the same way that it protects against pathogens. However, in rare cases cancer cells do not die within a single individual, but successfully pass between individuals, escaping the adaptive immune response and becoming a contagious cancer. There are two naturally occurring contagious cancers, Devil Facial Tumour Disease (DFTD), found in Tasmanian devils, and Canine Transmissible Venereal Tumour (CTVT), found in dogs. Despite sharing an ability to pass as allografts, these cancers have a very different impact on their hosts. While DFTD causes 100% mortality among infected devils and has had a devastating impact on the devil population, CTVT co-exists with its host in a manner that does not usually cause death of the dog. Although immune evasion strategies for CTVT have been defined, why DFTD is not rejected as an allograft is not understood. We have made progress in revealing mechanisms of immune evasion for DFTD both in vitro and in vivo, and here we compare how DFTD and CTVT interact with their respective hosts and avoid rejection. Our findings highlight factors that may be important for the evolution of contagious cancers and cancer more generally. Perhaps most importantly, this work has opened up important areas for future research, including the effect of epigenetic factors on immune escape mechanisms and the basis of a vaccine strategy that may protect Tasmanian devils against DFTD. PMID:23200636

  9. Genetic diversity and mutation of avian paramyxovirus serotype 1 (Newcastle disease virus) in wild birds and evidence for intercontinental spread

    USGS Publications Warehouse

    Ramey, Andy M.; Reeves, Andrew B.; Ogawa, Haruko; Ip, Hon S.; Imai, Kunitoshi; Bui, V. N.; Yamaguchi, Emi; Silko, N. Y.; Afonso, C.L.

    2013-01-01

    Avian paramyxovirus serotype 1 (APMV-1), or Newcastle disease virus, is the causative agent of Newcastle disease, one of the most economically important diseases for poultry production worldwide and a cause of periodic epizootics in wild birds in North America. In this study, we examined the genetic diversity of APMV-1 isolated from migratory birds sampled in Alaska, Japan, and Russia and assessed the evidence for intercontinental virus spread using phylogenetic methods. Additionally, we predicted viral virulence using deduced amino acid residues for the fusion protein cleavage site and estimated mutation rates for the fusion gene of class I and class II migratory bird isolates. All 73 isolates sequenced as part of this study were most closely related to virus genotypes previously reported for wild birds; however, five class II genotype I isolates formed a monophyletic clade exhibiting previously unreported genetic diversity, which met criteria for the designation of a new sub-genotype. Phylogenetic analysis of wild-bird isolates provided evidence for intercontinental virus spread, specifically viral lineages of APMV-1 class II genotype I sub-genotypes Ib and Ic. This result supports migratory bird movement as a possible mechanism for the redistribution of APMV-1. None of the predicted deduced amino acid motifs for the fusion protein cleavage site of APMV-1 strains isolated from migratory birds in Alaska, Japan, and Russia were consistent with those of previously identified virulent viruses. These data therefore provide no support for these strains contributing to the emergence of avian pathogens. The estimated mutation rates for fusion genes of class I and class II wild-bird isolates were faster than those reported previously for non-virulent APMV-1 strains. Collectively, these findings provide new insight into the diversity, spread, and evolution of APMV-1 in wild birds.

  10. Using friends as sensors to detect global-scale contagious outbreaks.

    PubMed

    Garcia-Herranz, Manuel; Moro, Esteban; Cebrian, Manuel; Christakis, Nicholas A; Fowler, James H

    2014-01-01

    Recent research has focused on the monitoring of global-scale online data for improved detection of epidemics, mood patterns, movements in the stock market political revolutions, box-office revenues, consumer behaviour and many other important phenomena. However, privacy considerations and the sheer scale of data available online are quickly making global monitoring infeasible, and existing methods do not take full advantage of local network structure to identify key nodes for monitoring. Here, we develop a model of the contagious spread of information in a global-scale, publicly-articulated social network and show that a simple method can yield not just early detection, but advance warning of contagious outbreaks. In this method, we randomly choose a small fraction of nodes in the network and then we randomly choose a friend of each node to include in a group for local monitoring. Using six months of data from most of the full Twittersphere, we show that this friend group is more central in the network and it helps us to detect viral outbreaks of the use of novel hashtags about 7 days earlier than we could with an equal-sized randomly chosen group. Moreover, the method actually works better than expected due to network structure alone because highly central actors are both more active and exhibit increased diversity in the information they transmit to others. These results suggest that local monitoring is not just more efficient, but also more effective, and it may be applied to monitor contagious processes in global-scale networks. PMID:24718030

  11. The spread of zoonoses and other infectious diseases through the international trade of animals and animal products.

    PubMed

    Seimenis, Aristarhos M

    2008-01-01

    For trade purposes, ever increasing quantities of food animals and animal products that are transported more rapidly than ever before are contributing to the spread of zoonoses and are creating threats on a permanent basis. Most countries in south-eastern Europe, the Mediterranean and the Middle East are increasing imports of food animals and meat and products of animal origin. They can become potential sources of zoonotic and other infectious diseases if controls are not performed under the most effective conditions. Developing countries with their organisational weakness are particularly vulnerable to fraudulent international trade practices of animals and animal products. To prevent such risks, the World Trade Organization, the World Organisation for Animal Health and their member countries support the measures stipulated in the Sanitary and Phytosanitary Agreement which targets the liberalisation of trade in animals and animal products under specific conditions while protecting public health and national economies. Vigilance must be exercised and appropriate inspection made at points of entry by veterinary and other authorities to ensure the strict implementation of international and national regulations. National legislation, appropriate infrastructures and the respect of international regulations can become barriers to avoid animal trade, contributing to the spread of zoonotic and other infectious diseases. PMID:20411486

  12. An approach for de-identification of point locations of livestock premises for further use in disease spread modeling.

    PubMed

    Martin, Michael K; Helm, Julie; Patyk, Kelly A

    2015-06-15

    We describe a method for de-identifying point location data used for disease spread modeling to allow data custodians to share data with modeling experts without disclosing individual farm identities. The approach is implemented in an open-source software program that is described and evaluated here. The program allows a data custodian to select a level of de-identification based on the K-anonymity statistic. The program converts a file of true farm locations and attributes into a file appropriate for use in disease spread modeling with the locations randomly modified to prevent re-identification based on location. Important epidemiological relationships such as clustering are preserved to as much as possible to allow modeling similar to those using true identifiable data. The software implementation was verified by visual inspection and basic descriptive spatial analysis of the output. Performance is sufficient to allow de-identification of even large data sets on desktop computers available to any data custodian. PMID:25944175

  13. The development of pathogen resistance in Daphnia magna: implications for disease spread in age-structured populations

    PubMed Central

    Garbutt, Jennie S.; O'Donoghue, Anna J. P.; McTaggart, Seanna J.; Wilson, Philip J.; Little, Tom J.

    2014-01-01

    Immunity in vertebrates is well established to develop with time, but the ontogeny of defence in invertebrates is markedly less studied. Yet, age-specific capacity for defence against pathogens, coupled with age structure in populations, has widespread implications for disease spread. Thus, we sought to determine the susceptibility of hosts of different ages in an experimental invertebrate host–pathogen system. In a series of experiments, we show that the ability of Daphnia magna to resist its natural bacterial pathogen Pasteuria ramosa changes with host age. Clonal differences make it difficult to draw general conclusions, but the majority of observations indicate that resistance increases early in the life of D. magna, consistent with the idea that the defence system develops with time. Immediately following this, at about the time when a daphnid would be most heavily investing in reproduction, resistance tends to decline. Because many ecological factors influence the age structure of Daphnia populations, our results highlight a broad mechanism by which ecological context can affect disease epidemiology. We also show that a previously observed protective effect of restricted maternal food persists throughout the entire juvenile period, and that the protective effect of prior treatment with a small dose of the pathogen (‘priming’) persists for 7 days, observations that reinforce the idea that immunity in D. magna can change over time. Together, our experiments lead us to conclude that invertebrate defence capabilities have an ontogeny that merits consideration with respect to both their immune systems and the epidemic spread of infection. PMID:25214486

  14. Representation of animal distributions in space: how geostatistical estimates impact simulation modeling of foot-and-mouth disease spread.

    PubMed

    Highfield, Linda; Ward, Michael P; Laffan, Shawn W

    2008-01-01

    Modeling potential disease spread in wildlife populations is important for predicting, responding to and recovering from a foreign animal disease incursion. To make spatial epidemic predictions, the target animal species of interest must first be represented in space. We conducted a series of simulation experiments to determine how estimates of the spatial distribution of white-tailed deer impact the predicted magnitude and distribution of foot-and-mouth disease (FMD) outbreaks. Outbreaks were simulated using a susceptible-infected-recovered geographic automata model. The study region was a 9-county area (24 000 km(2)) of southern Texas. Methods used for creating deer distributions included dasymetric mapping, kriging and remotely sensed image analysis. The magnitudes and distributions of the predicted outbreaks were evaluated by comparing the median number of deer infected and median area affected (km(2)), respectively. The methods were further evaluated for similar predictive power by comparing the model predicted outputs with unweighted pair group method with arithmetic mean (UPGMA) clustering. There were significant differences in the estimated number of deer in the study region, based on the geostatistical estimation procedure used (range: 385 939-768 493). There were also substantial differences in the predicted magnitude of the FMD outbreaks (range: 1 563-8 896) and land area affected (range: 56-447 km(2)) for the different estimated animal distributions. UPGMA clustering indicated there were two main groups of distributions, and one outlier. We recommend that one distribution from each of these two groups be used to model the range of possible outbreaks. Methods included in cluster 1 (such as county-level disaggregation) could be used in conjunction with any of the methods in cluster 2, which included kriging, NDVI split by ecoregion, or disaggregation at the regional level, to represent the variability in the model predicted outbreak distributions. How animal populations are represented needs to be considered in all spatial disease spread models. PMID:18258171

  15. Occurrence of Stolbur Phytoplasma Disease in Spreading Type Petunia hybrida Cultivars in Korea

    PubMed Central

    Chung, Bong Nam; Jeong, Myeong Il; Choi, Seung Kook; Joa, Jae Ho; Choi, Kyeong San; Choi, In Myeong

    2013-01-01

    In January 2012, spreading type petunia cv. Wave Pink plants showing an abnormal growth habit of sprouting unusual multiple plantlets from the lateral buds were collected from a greenhouse in Gwacheon, Gyeonggi Province, Korea. The presence of phytoplasma was investigated using PCR with the primer pairs P1/P6, and R16F1/R1 for nested-PCR. In the nested PCR, 1,096 bp PCR products were obtained, and through sequencing 12 Pet-Stol isolates were identified. Comparison of the nucleotide sequences of 16S rRNA gene of the 12 Pet-Stol isolates with other phytoplasmas belonging to aster yellows or Stolbur showed that Pet-Stol isolates were members of Stolbur. The presence of phytoplasma in petunia was also confirmed by microscopic observation of the pathogens. In this study, Stolbur phytoplasma was identified from spreading type petunia cultivars by sequence analysis of 16S rRNA gene of phytoplasma and microscopic observation of phytoplasma bodies. This is the first report of Stolbur phytoplasma in commercial Petunia hybrida cultivars. PMID:25288978

  16. LETTER Parasite consumption and host interference can inhibit disease spread in dense populations

    E-print Network

    Hall, Spencer

    alternatives when fit to experimental data using a zooplankton host (Daphnia dentifera) that consumes spores, a mechanistic approach to transmission can reveal new insights into disease outbreaks. Keywords Daphnia lack potentially important biology ­ they cannot identify the mechanisms underlying transmission

  17. Intercontinental spread of a genetically distinctive complex of clones of Neisseria meningitidis causing epidemic disease.

    PubMed Central

    Caugant, D A; Frøholm, L O; Bøvre, K; Holten, E; Frasch, C E; Mocca, L F; Zollinger, W D; Selander, R K

    1986-01-01

    Strains of Neisseria meningitidis responsible for an epidemic of meningococcal disease occurring in Norway since the mid-1970s and for recent increases in the incidence of disease in several other parts of Europe have been identified by multilocus enzyme electrophoresis as members of a distinctive group of 22 closely related clones (the ET-5 complex). Clones of this complex have also colonized South Africa, Chile, Cuba, and Florida, where they have been identified as the causative agents of recent outbreaks of meningococcal disease. There is strong circumstantial evidence that outbreaks of disease occurring in Miami in 1981 and 1982 were caused in large part by bacteria that reached Florida via human immigrants from Cuba. PMID:3088568

  18. The impact of seasonal variability in wildlife populations on the predicted spread of foot and mouth disease

    PubMed Central

    Highfield, Linda D.; Ward, Michael P.; Laffan, Shawn W.; Norby, Bo; Wagner, Gale

    2009-01-01

    Modeling potential disease spread in wildlife populations is important for predicting, responding to and recovering from a foreign animal disease incursion such as foot and mouth disease (FMD). We conducted a series of simulation experiments to determine how seasonal estimates of the spatial distribution of white-tailed deer impact the predicted magnitude and distribution of potential FMD outbreaks. Outbreaks were simulated in a study area comprising two distinct ecoregions in South Texas, USA, using a susceptible-latent-infectious-resistant geographic automata model (Sirca). Seasonal deer distributions were estimated by spatial autoregressive lag models and the normalized difference vegetation index. Significant (P < 0.0001) differences in both the median predicted number of deer infected and number of herds infected were found both between seasons and between ecoregions. Larger outbreaks occurred in winter within the higher deer-density ecoregion, whereas larger outbreaks occurred in summer and fall within the lower deer-density ecoregion. Results of this simulation study suggest that the outcome of an FMD incursion in a population of wildlife would depend on the density of the population infected and when during the year the incursion occurs. It is likely that such effects would be seen for FMD incursions in other regions and countries, and for other diseases, in cases in which a potential wildlife reservoir exists. Study findings indicate that the design of a mitigation strategy needs to take into account population and seasonal characteristics. PMID:19134466

  19. The impact of seasonal variability in wildlife populations on the predicted spread of foot and mouth disease.

    PubMed

    Highfield, Linda D; Ward, Michael P; Laffan, Shawn W; Norby, Bo; Wagner, Gale

    2009-01-01

    Modeling potential disease spread in wildlife populations is important for predicting, responding to and recovering from a foreign animal disease incursion such as foot and mouth disease (FMD). We conducted a series of simulation experiments to determine how seasonal estimates of the spatial distribution of white-tailed deer impact the predicted magnitude and distribution of potential FMD outbreaks. Outbreaks were simulated in a study area comprising two distinct ecoregions in South Texas, USA, using a susceptible-latent-infectious-resistant geographic automata model (Sirca). Seasonal deer distributions were estimated by spatial autoregressive lag models and the normalized difference vegetation index. Significant (P < 0.0001) differences in both the median predicted number of deer infected and number of herds infected were found both between seasons and between ecoregions. Larger outbreaks occurred in winter within the higher deer-density ecoregion, whereas larger outbreaks occurred in summer and fall within the lower deer-density ecoregion. Results of this simulation study suggest that the outcome of an FMD incursion in a population of wildlife would depend on the density of the population infected and when during the year the incursion occurs. It is likely that such effects would be seen for FMD incursions in other regions and countries, and for other diseases, in cases in which a potential wildlife reservoir exists. Study findings indicate that the design of a mitigation strategy needs to take into account population and seasonal characteristics. PMID:19134466

  20. The French Connection: The First Large Population-Based Contact Survey in France Relevant for the Spread of Infectious Diseases

    PubMed Central

    Béraud, Guillaume; Kazmercziak, Sabine; Beutels, Philippe; Levy-Bruhl, Daniel; Lenne, Xavier; Mielcarek, Nathalie; Yazdanpanah, Yazdan; Boëlle, Pierre-Yves; Hens, Niel; Dervaux, Benoit

    2015-01-01

    Background Empirical social contact patterns are essential to understand the spread of infectious diseases. To date, no such data existed for France. Although infectious diseases are frequently seasonal, the temporal variation of contact patterns has not been documented hitherto. Methods COMES-F is the first French large-scale population survey, carried out over 3 different periods (February-March, April, April-May) with some participants common to the first and the last period. Participants described their contacts for 2 consecutive days, and reported separately on professional contacts when typically over 20 per day. Results 2033 participants reported 38 881 contacts (weighted median [first quartile-third quartile]: 8[5–14] per day), and 54 378 contacts with supplementary professional contacts (9[5–17]). Contrary to age, gender, household size, holidays, weekend and occupation, period of the year had little influence on the number of contacts or the mixing patterns. Contact patterns were highly assortative with age, irrespective of the location of the contact, and gender, with women having 8% more contacts than men. Although most contacts occurred at home and at school, the inclusion of professional contacts modified the structure of the mixing patterns. Holidays and weekends reduced dramatically the number of contacts, and as proxies for school closure, reduced R0 by 33% and 28%, respectively. Thus, school closures could have an important impact on the spread of close contact infections in France. Conclusions Despite no clear evidence for temporal variation, trends suggest that more studies are needed. Age and gender were found important determinants of the mixing patterns. Gender differences in mixing patterns might help explain gender differences in the epidemiology of infectious diseases. PMID:26176549

  1. Predicting the Spread of Plant Disease: Analysis of an Infinite-Dimensional Leslie Matrix Model for

    E-print Network

    Powell, James

    of Split, Croatia #12;1 Introduction Plant diseases, caused by fungi, bacteria, viruses and other in plant pop- ulations, o¨omycetes have much in common with fungal pathogens. Their life cycle includes plant pathogenic fungi is the production of airborne spores from sporulating bodies. Spores are released

  2. Predicting ectotherm disease vector spread—benefits from multidisciplinary approaches and directions forward

    NASA Astrophysics Data System (ADS)

    Thomas, Stephanie Margarete; Beierkuhnlein, Carl

    2013-05-01

    The occurrence of ectotherm disease vectors outside of their previous distribution area and the emergence of vector-borne diseases can be increasingly observed at a global scale and are accompanied by a growing number of studies which investigate the vast range of determining factors and their causal links. Consequently, a broad span of scientific disciplines is involved in tackling these complex phenomena. First, we evaluate the citation behaviour of relevant scientific literature in order to clarify the question "do scientists consider results of other disciplines to extend their expertise?" We then highlight emerging tools and concepts useful for risk assessment. Correlative models (regression-based, machine-learning and profile techniques), mechanistic models (basic reproduction number R 0) and methods of spatial regression, interaction and interpolation are described. We discuss further steps towards multidisciplinary approaches regarding new tools and emerging concepts to combine existing approaches such as Bayesian geostatistical modelling, mechanistic models which avoid the need for parameter fitting, joined correlative and mechanistic models, multi-criteria decision analysis and geographic profiling. We take the quality of both occurrence data for vector, host and disease cases, and data of the predictor variables into consideration as both determine the accuracy of risk area identification. Finally, we underline the importance of multidisciplinary research approaches. Even if the establishment of communication networks between scientific disciplines and the share of specific methods is time consuming, it promises new insights for the surveillance and control of vector-borne diseases worldwide.

  3. Predicting ectotherm disease vector spread--benefits from multidisciplinary approaches and directions forward.

    PubMed

    Thomas, Stephanie Margarete; Beierkuhnlein, Carl

    2013-05-01

    The occurrence of ectotherm disease vectors outside of their previous distribution area and the emergence of vector-borne diseases can be increasingly observed at a global scale and are accompanied by a growing number of studies which investigate the vast range of determining factors and their causal links. Consequently, a broad span of scientific disciplines is involved in tackling these complex phenomena. First, we evaluate the citation behaviour of relevant scientific literature in order to clarify the question "do scientists consider results of other disciplines to extend their expertise?" We then highlight emerging tools and concepts useful for risk assessment. Correlative models (regression-based, machine-learning and profile techniques), mechanistic models (basic reproduction number R0) and methods of spatial regression, interaction and interpolation are described. We discuss further steps towards multidisciplinary approaches regarding new tools and emerging concepts to combine existing approaches such as Bayesian geostatistical modelling, mechanistic models which avoid the need for parameter fitting, joined correlative and mechanistic models, multi-criteria decision analysis and geographic profiling. We take the quality of both occurrence data for vector, host and disease cases, and data of the predictor variables into consideration as both determine the accuracy of risk area identification. Finally, we underline the importance of multidisciplinary research approaches. Even if the establishment of communication networks between scientific disciplines and the share of specific methods is time consuming, it promises new insights for the surveillance and control of vector-borne diseases worldwide. PMID:23532546

  4. The African buffalo: a villain for inter-species spread of infectious diseases in southern Africa.

    PubMed

    Michel, Anita L; Bengis, Roy G

    2012-01-01

    The African buffalo (Syncerus caffer) is a large wild bovid which until recently ranged across all but the driest parts of sub-Saharan Africa, and their local range being limited to about 20 km from surface water. They are of high ecological value due to their important role as bulk feeders in the grazing hierarchy. They also have high economic value, because they are one of the sought after 'Big Five' in the eco-tourism industry. In Africa, buffaloes have been recognised for some time as an important role player in the maintenance and transmission of a variety of economically important livestock diseases at the wildlife and/or livestock interface. These include African strains of foot-and-mouth disease (FMD), Corridor disease (theileriosis), bovine tuberculosis and bovine brucellosis. For a number of other diseases of veterinary importance, African buffaloes may also serve as amplifier or incidental host, whereby infection with the causative pathogens may cause severe clinical signs such as death or abortion as in the case of anthrax and Rift Valley fever, or remain mild or subclinical for example heartwater. The long term health implications of most of those infections on the buffalo at a population level is usually limited, and they do not pose a threat on the population's survival. Because of their ability to harbour and transmit important diseases to livestock, their sustainable future in ecotourism, trade and transfrontier conservation projects become complex and costly and reliable diagnostic tools are required to monitor these infections in buffalo populations. PMID:23327373

  5. A review of trends in the distribution of vector-borne diseases: is international trade contributing to their spread?

    PubMed

    de La Rocque, S; Balenghien, T; Halos, L; Dietze, K; Claes, F; Ferrari, G; Guberti, V; Slingenbergh, J

    2011-04-01

    It is difficult to determine the part that international trade has played in the expansion of vector-borne diseases, because of the multitude of factors that affect the transformation of habitats and the interfaces between vectors and hosts. The introduction of pathogens through trade in live animals or products of animal origin, as well as the arrival of arthropod vectors, is probably quite frequent but the establishment of an efficient transmission system that develops into a disease outbreak remains the exception. In this paper, based on well-documented examples, the authors review the ecological and epidemiological characteristics of vector-borne diseases that may have been affected in their spread and change of distribution by international trade. In addition, they provide a detailed analysis of the risks associated with specific trade routes and recent expansions of vector populations. Finally, the authors highlight the importance, as well as the challenges, of preventive surveillance and regulation. The need for improved monitoring of vector populations and a readiness to face unpredictable epidemiological events are also emphasised, since this will require rapid reaction, not least in the regulatory context. PMID:21809758

  6. PhD project opportunities on Tasmanian devils and their contagious cancer

    E-print Network

    Wapstra, Erik

    PhD project opportunities on Tasmanian devils and their contagious cancer School of Zoology, the world's largest marsupial carnivore, are disappearing in the wild from a novel contagious cancer. Almost on Tasmanian devils and their contagious cancer School of Zoology, University of Tasmania The project

  7. Comparative effects of avoidance and vaccination in disease spread on a dynamic small-world network

    NASA Astrophysics Data System (ADS)

    Stone, Thomas E.; Jones, Matthew M.; McKay, Susan R.

    2010-12-01

    Dynamic small-world contact networks have fixed short range links and time-varying stochastic long range links. They are used to model mobile populations or as minimal models for traditional small-world networks. Here we study the relative effects of vaccinations and avoidance of infected individuals in a susceptible-infected-recovered (SIR) epidemic model on a dynamic small-world network. We derive the critical mobility required for an outbreak to occur as a function of the disease’s infectivity, recovery rate, avoidance rate, and vaccination rate. We also derive an expression that allows us to calculate the amount of vaccination and/or avoidance necessary to prevent an epidemic. Calculated quantities show excellent agreement with simulations.

  8. Incorporating social contact data in spatio-temporal models for infectious disease spread

    E-print Network

    Meyer, Sebastian

    2015-01-01

    Routine public health surveillance of notifiable infectious diseases gives rise to weekly counts of reported cases - possibly stratified by region and/or age group. A well-established approach to the statistical analysis of such surveillance data are endemic-epidemic time-series models. The temporal dependence inherent to communicable diseases is thereby taken into account by an observation-driven formulation conditioning on past counts. Additional spatial dynamics in areal-level counts are largely driven by human travel and can be captured by power-law weights based on the order of adjacency. However, social contacts are highly assortative also with respect to age. For example, characteristic pathways of directly transmitted pathogens are linked to childcare facilities, schools and nursing homes. We therefore investigate how a spatio-temporal endemic-epidemic model can be extended to take social contact data into account. The approach is illustrated in a case study on norovirus gastroenteritis in Berlin, 201...

  9. Broad and fine-scale genetic analysis of white-tailed deer populations: estimating the relative risk of chronic wasting disease spread

    PubMed Central

    Cullingham, Catherine I; Merrill, Evelyn H; Pybus, Margo J; Bollinger, Trent K; Wilson, Gregory A; Coltman, David W

    2011-01-01

    Chronic wasting disease is a transmissible spongiform encephalopathy of cervids, similar to sheep scrapie that has only recently been detected in wild populations of white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus hemionus) in western Canada. Relatively little is known about local transmission dynamics of the disease or the potential for long-distance spread. We analysed the population genetic structure of over 2000 white-tailed deer sampled from Alberta, British Columbia, and Saskatchewan using microsatellite profiles and mtDNA sequencing to assess the relative risk of disease spread. There was very little differentiation among subpopulations and a weak trend of increasing differentiation with geographic distance. This suggests that the potential for long-distance disease spread through the dispersal of infected individuals is possible, yet the risk of spread should gradually diminish with distance from infection foci. Within subpopulations, females were more related than expected by chance (R > 0) within a radius of approximately 500 m. Sex-biased philopatry and social interactions among related females may facilitate local disease transmission within social groups. Local herd reduction may therefore be an effective tool for reducing the disease prevalence when implemented at the appropriate spatial scale. PMID:25567957

  10. Mycoplasma agalactiae, an Etiological Agent of Contagious Agalactia in Small Ruminants: A Review

    PubMed Central

    Kumar, Amit; Rahal, Anu; Verma, Amit Kumar

    2014-01-01

    Mycoplasma agalactiae is one of the causal agents of classical contagious agalactia (CA), a serious, economically important but neglected enzootic disease of small ruminants. It occurs in many parts of the world and most notably in the Mediterranean Basin. Following the infection common complications are septicaemia, mastitis, arthritis, pleurisy, pneumonia, and keratoconjunctivitis. Primary or tentative diagnosis of the organism is based upon clinical signs. Various serological tests, namely, growth precipitation, immunofluorescence, complement fixation test, haemagglutination inhibition, agglutination, immunodiffusion, enzyme immunoassays, immunoelectrophoresis, blotting techniques, and others, are available. Molecular tools seem to be much more sensitive, specific, and faster and help to differentiate various strains. The real-time PCR, multiplex PCR, quantitative PCR, PCR-RFLP, MLST, and gene probes, complementary to segments of chromosomal DNA or 16S ribosomal RNA (rRNA), have strengthened the diagnosis of M. agalactiae. Both live attenuated and adjuvant (alum precipitated or saponified) inactivated vaccines are available with greater use of inactivated ones due to lack of side effects. The present review discusses the etiology, epidemiology, pathogenesis, and clinical signs of contagious agalactia in small ruminants along with trends and advances in its diagnosis, treatment, vaccination, prevention, and control strategies that will help in countering this disease. PMID:25097796

  11. International trade and the spread of animal diseases: assessing the risks.

    PubMed

    Murray, N

    2006-01-01

    Decisions about managing animal and zoonotic disease risks associated with the international trade in animals and animal products are inevitably made in the face of varying degrees of uncertainty. The risk analysis framework of the Office International des Epizooties (OIE: World organisation for animal health) provides a structured approach that facilitates the identification, assessment, management and communication of these risks. By ensuring that an analysis is transparent and subjected to scientific review, stakeholders and trading partners can be assured that a reasonable level of objectivity is obtained, that the measures adopted are appropriate and that international obligations, outlined in the Agreement on the Application of Sanitary and Phytosanitary Measures of the World Trade Organization, are fulfilled. PMID:20429068

  12. The SIS Model of Epidemic Spreading in a Hierarchical Social Network

    NASA Astrophysics Data System (ADS)

    Grabowski, A.; Kosinski, R. A.

    2005-05-01

    The phenomenon of epidemic spreading in a population with a hierarchical structure of interpersonal interactions is described and investigated numerically. The SIS model with temporal immunity to a disease and a time of incubation is used. In our model spatial localization of individuals belonging to different social groups, effectiveness of different interpersonal interactions and the mobility of a contemporary community are taken into account. The structure of interpersonal connections is based on a scale-free network. The influence of the structure of the social network on typical relations characterizing the spreading process, like a range of epidemic and epidemic curves, is discussed. The probability that endemic state occurs is also calculated. Surprisingly it occurs, that less contagious diseases has greater chance to survive. The influence of preventive vaccinations on the spreading process is investigated and critical range of vaccinations that is sufficient for the suppression of an epidemic is calculated. Our results of numerical calculations are compared with the solutions of the master equation for the spreading process, and good agreement is found.

  13. [Health Communication: Preventing the Spread of Ebola Virus Disease in the Portuguese Spoken African Countries--Methodology KISS & KEYWORDS].

    PubMed

    Santiago, Isabel De; Miguel, José Pereira; Antunes, Francisco

    2015-01-01

    In this work, Health Communication is considered as an important discipline in medicine and health sciences for his role as true determinant of health. We highlight their contribution to health promotion and disease prevention. Thus, the Health Communication Plan (PCS): Preventing the spread of Ebola virus disease in the Portuguese Speaking African Countries - KISS & KEYWORDS methodology is a tool that aims to minimize the risk of infection by Ebola virus in the Portuguese Speaking African Countries and also train for a general improvement of health conditions of the local populations. In the PCS design are especially considered the social and cultural contexts of the target populations, especially the customs, traditions and religion. Health Communication is considered as an Essential Function of Public Health and its main is to provide a population-based approach. The target of communication actions are population groups in addition to the individual communication, target-audiences are people without access to the media, in Guinea Bissau, Cape Verde and Sao Tome and Principe. Under the communication plan uses the methodology, models and practices both by media professionals as health. A proximity approach and cultural mediation, previously identified key facts, are defined objectives; outlines to the Plan in concrete and its implementation methodology (target-audience and following intervention, materials to be used and key-messages and partners to mobilize) following the World Health Organisation standards. PMID:26061502

  14. Heterogeneity in the spread and control of infectious disease: consequences for the elimination of canine rabies

    PubMed Central

    Ferguson, Elaine A.; Hampson, Katie; Cleaveland, Sarah; Consunji, Ramona; Deray, Raffy; Friar, John; Haydon, Daniel T.; Jimenez, Joji; Pancipane, Marlon; Townsend, Sunny E.

    2015-01-01

    Understanding the factors influencing vaccination campaign effectiveness is vital in designing efficient disease elimination programmes. We investigated the importance of spatial heterogeneity in vaccination coverage and human-mediated dog movements for the elimination of endemic canine rabies by mass dog vaccination in Region VI of the Philippines (Western Visayas). Household survey data was used to parameterise a spatially-explicit rabies transmission model with realistic dog movement and vaccination coverage scenarios, assuming a basic reproduction number for rabies drawn from the literature. This showed that heterogeneous vaccination reduces elimination prospects relative to homogeneous vaccination at the same overall level. Had the three vaccination campaigns completed in Region VI in 2010–2012 been homogeneous, they would have eliminated rabies with high probability. However, given the observed heterogeneity, three further campaigns may be required to achieve elimination with probability 0.95. We recommend that heterogeneity be reduced in future campaigns through targeted efforts in low coverage areas, even at the expense of reduced coverage in previously high coverage areas. Reported human-mediated dog movements did not reduce elimination probability, so expending limited resources on restricting dog movements is unnecessary in this endemic setting. Enhanced surveillance will be necessary post-elimination, however, given the reintroduction risk from long-distance dog movements. PMID:26667267

  15. Heterogeneity in the spread and control of infectious disease: consequences for the elimination of canine rabies.

    PubMed

    Ferguson, Elaine A; Hampson, Katie; Cleaveland, Sarah; Consunji, Ramona; Deray, Raffy; Friar, John; Haydon, Daniel T; Jimenez, Joji; Pancipane, Marlon; Townsend, Sunny E

    2015-01-01

    Understanding the factors influencing vaccination campaign effectiveness is vital in designing efficient disease elimination programmes. We investigated the importance of spatial heterogeneity in vaccination coverage and human-mediated dog movements for the elimination of endemic canine rabies by mass dog vaccination in Region VI of the Philippines (Western Visayas). Household survey data was used to parameterise a spatially-explicit rabies transmission model with realistic dog movement and vaccination coverage scenarios, assuming a basic reproduction number for rabies drawn from the literature. This showed that heterogeneous vaccination reduces elimination prospects relative to homogeneous vaccination at the same overall level. Had the three vaccination campaigns completed in Region VI in 2010-2012 been homogeneous, they would have eliminated rabies with high probability. However, given the observed heterogeneity, three further campaigns may be required to achieve elimination with probability 0.95. We recommend that heterogeneity be reduced in future campaigns through targeted efforts in low coverage areas, even at the expense of reduced coverage in previously high coverage areas. Reported human-mediated dog movements did not reduce elimination probability, so expending limited resources on restricting dog movements is unnecessary in this endemic setting. Enhanced surveillance will be necessary post-elimination, however, given the reintroduction risk from long-distance dog movements. PMID:26667267

  16. Connecting human behavior and infectious disease spreading. Comment on "Coupled disease-behavior dynamics on complex networks: A review" by Wang et al.

    NASA Astrophysics Data System (ADS)

    Holme, Petter

    2015-12-01

    Vaccination against measles is one of the great success stories of 20th century medicine. In the USA, before the introduction of the vaccine in 1963, three to four million adolescents were infected annually, around 500 died, around 5000 got serious complications (primarily encephalitis, swelling of the brain), and around 50,000 were hospitalized [7]. With the vaccine, measles virtually vanished and by 2000 it was declared extinct from the USA. This was, however, not the end of the story. There is still a small fraction of parents who do not let their children be vaccinated. The reasons vary-fear of side effects, an aversion of exposing children to something "unnatural", and a large number of other ideas. (For a non-academic account of the psychology of vaccination, we recommend Eula Biss's On Immunity[3].) The last few decades, anti-vaccination ideas have been spreading in social media and united people opposing vaccination into something of a movement [4]. In December 2014 there was a first larger outbreak (over 500 cases) of the century, centered around Disneyland (Anaheim, California) [10], and the anti-vaccination movement got much of the blame [4]. This example illustrates how ideas and opinions-that just like diseases are spreading over networks of people-can facilitate outbreaks. The reverse is, thankfully, more common-people, aware of an emerging outbreak, try to lower the chance of contagion by improving hygiene etc., which impedes the outbreak.

  17. Ti Plasmids from Agrobacterium Characterize Rootstock Clones That Initiated a Spread of Crown Gall Disease in Mediterranean Countries

    PubMed Central

    Pionnat, Sandrine; Keller, Harald; Héricher, Delphine; Bettachini, Andrée; Dessaux, Yves; Nesme, Xavier; Poncet, Christine

    1999-01-01

    Crown gall caused by Agrobacterium is one of the predominant diseases encountered in rose cultures. However, our current knowledge of the bacterial strains that invade rose plants and the way in which they spread is limited. Here, we describe the integrated physiological and molecular analyses of 30 Agrobacterium isolates obtained from crown gall tumors and of several reference strains. Characterization was based on the determination of the biovar, analysis of 16S ribosomal DNA restriction fragment length polymorphisms by PCR (PCR-RFLP), elucidation of the opine type, and PCR-RFLP analysis of genes involved in virulence and oncogenesis. This study led to the classification of rose isolates into seven groups with common chromosome characteristics and seven groups with common Ti plasmid characteristics. Altogether, the rose isolates formed 14 independent groups, with no specific association of plasmid- and chromosome-encoded traits. The predominant Ti plasmid characteristic was that 16 of the isolates induced the production of the uncommon opine succinamopine, while the other 14 were nopaline-producing isolates. With the exception of one, all succinamopine Ti plasmids belonged to the same plasmid group. Conversely, the nopaline Ti plasmids belonged to five groups, one of these containing seven isolates. We showed that outbreaks of disease provoked by the succinamopine-producing isolates in different countries and nurseries concurred with a common origin of specific rootstock clones. Similarly, groups of nopaline-producing isolates were associated with particular rootstock clones. These results strongly suggest that the causal agent of crown gall disease in rose plants is transmitted via rootstock material. PMID:10473434

  18. Immunizing against Prejudice: Effects of Disease Protection on Attitudes toward out-Groups

    E-print Network

    Ackerman, Joshua

    Contemporary interpersonal biases are partially derived from psychological mechanisms that evolved to protect people against the threat of contagious disease. This behavioral immune system effectively promotes disease ...

  19. POST-HURRICANE ANALYSIS OF CITRUS CANKER II: PREDICTIVE MODEL ESTIMATION OF DISEASE SPREAD AND AREA POTENTIALLY IMPACTED BY VARIOUS ERADICATION PROTOCOLS FOLLOWING CATASTROPHIC WEATHER EVENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The affect of 2005 Hurricane Wilma on the dissemination of Xanthomonas axonopodis pv. citri (Xac), the cause of Asiatic citrus canker (ACC), and subsequent disease development was examined and predictions for the areas into which Xac was likely to have spread from known sources of infection was deve...

  20. MODELING THE SPREAD OF EBOLA Ebola is a rare and deadly disease caused by infection with a strain of Ebola virus. The current

    E-print Network

    Morrow, James A.

    MODELING THE SPREAD OF EBOLA 1. Summary Ebola is a rare and deadly disease caused by infection with a strain of Ebola virus. The current 2014 Ebola epidemic outbreak in West Africa (first cases notified in March 2014) is the largest and most complex Ebola outbreak since the Ebola virus was first discovered

  1. An outbreak of contagious bovine pleuropneumonia in Ngamiland district of north-western Botswana.

    PubMed

    Amanfu, W; Masupu, K V; Adom, E K; Raborokgwe, M V; Bashiruddin, J B

    1998-07-11

    An outbreak of contagious bovine pleuropneumonia (CBPP) was detected in Botswana in 1995 after more than half a century of freedom from the disease. Lung tissues, pleural fluids, nasal swabs and serum samples were examined in laboratories in Botswana, South Africa and Namibia and the findings were confirmed in Italy. The disease was confirmed as CBPP from the gross and histopathological changes in the lungs of affected animals and by the culture of the agent of CBPP, Mycoplasma mycoides subspecies mycoides, small colony variant (MmmSC). These findings were supported by the demonstration of specific complement-fixing antibodies and the production of polymerase chain reaction products of MmmSC. PMID:9699252

  2. Meniere's Disease

    MedlinePLUS

    ... Overview What is Meniere's disease? Meniere's (say: "men-ears") disease is a problem with your inner ear. No ... a build up of fluid in the inner ear. Although it can be troublesome, Meniere's disease is not contagious, and it isn't fatal. ...

  3. Optimizing Hybrid Spreading in Metapopulations

    PubMed Central

    Zhang, Changwang; Zhou, Shi; Miller, Joel C.; Cox, Ingemar J.; Chain, Benjamin M.

    2015-01-01

    Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics. PMID:25923411

  4. Use of penicillin and streptomycin to reduce spread of bacterial coldwater disease I: antibiotics in sperm extenders.

    PubMed

    Oplinger, Randall W; Wagner, Eric J

    2015-03-01

    Bacterial coldwater disease caused by Flavobacterium psychrophilum has led to the loss of significant numbers of hatchery-reared salmonids. The bacteria can be spread from parent to progeny within contaminated sperm and ovarian fluid. Methods for disinfecting ovarian fluid and unfertilized eggs are available, but methods for disinfecting sperm have not been described. In this study we determined whether sperm extenders containing a mixture of penicillin and streptomycin can be used to eliminate F. psychrophilum. In vitro trials demonstrated that when Rainbow Trout Oncorhynchus mykiss sperm is mixed with an extender, a 15-min exposure to 0.197 mg penicillin plus 0.313 mg/mL streptomycin is effective at killing the bacteria and has no effect on sperm motility. Small-scale trials showed that egg fertilization rates were not reduced when sperm held in an extender solution containing the same antibiotic mixture for 15 min was used to fertilize eggs. Production-scale trials, however, showed a roughly 18% decrease in egg fertilization rate when sperm stored in an antibiotic containing extender was used. To determine why a reduction in fertilization capacity was observed, a small-scale experiment testing the fertilization of eggs with larger quantities of sperm was performed and showed that increasing the volume of sperm used did not increase fertilization rates. Our results demonstrate that extenders containing penicillin and streptomycin can be used to disinfect sperm, especially when small quantities of eggs are fertilized, but factors negatively affecting egg fertilization and survival on a production scale still need further investigation. PMID:25581335

  5. Fatal transmission of contagious caprine pleuropneumonia to an Arabian oryx (Oryx leucoryx).

    PubMed

    Chaber, A L; Lignereux, L; Al Qassimi, M; Saegerman, C; Manso-Silván, L; Dupuy, V; Thiaucourt, F

    2014-09-17

    Contagious caprine pleuropneumonia (CCPP) is an infectious respiratory disease mainly affecting domestic goats. As CCPP has never been documented in grazing antelopes (subfamily hippotraginae), they were not considered susceptible. Mycoplasma capricolum subspecies capripneumoniae (Mccp) was isolated from pleural liquid collected during the necropsy of a severely emaciated Arabian oryx with mild nasal discharge. The Mccp isolate was then genotyped using a multilocus sequence scheme; the sequence type was identical to the Mccp strain previously identified in a sand gazelle from a nearby enclosure. This case shows for the first time that members of the hippotraginae subfamily, here the Arabian oryx, can be affected by CCPP. In addition, genotyping shows that the oryx was most probably infected, at a distance, by sand gazelles. PMID:25069622

  6. Efficient detection of contagious outbreaks in massive metropolitan encounter networks.

    PubMed

    Sun, Lijun; Axhausen, Kay W; Lee, Der-Horng; Cebrian, Manuel

    2014-01-01

    Physical contact remains difficult to trace in large metropolitan networks, though it is a key vehicle for the transmission of contagious outbreaks. Co-presence encounters during daily transit use provide us with a city-scale time-resolved physical contact network, consisting of 1 billion contacts among 3 million transit users. Here, we study the advantage that knowledge of such co-presence structures may provide for early detection of contagious outbreaks. We first examine the "friend sensor" scheme--a simple, but universal strategy requiring only local information--and demonstrate that it provides significant early detection of simulated outbreaks. Taking advantage of the full network structure, we then identify advanced "global sensor sets", obtaining substantial early warning times savings over the friends sensor scheme. Individuals with highest number of encounters are the most efficient sensors, with performance comparable to individuals with the highest travel frequency, exploratory behavior and structural centrality. An efficiency balance emerges when testing the dependency on sensor size and evaluating sensor reliability; we find that substantial and reliable lead-time could be attained by monitoring only 0.01% of the population with the highest degree. PMID:24903017

  7. Hitting Is Contagious in Baseball: Evidence from Long Hitting Streaks

    PubMed Central

    Bock, Joel R.; Maewal, Akhilesh; Gough, David A.

    2012-01-01

    Data analysis is used to test the hypothesis that “hitting is contagious”. A statistical model is described to study the effect of a hot hitter upon his teammates’ batting during a consecutive game hitting streak. Box score data for entire seasons comprising streaks of length games, including a total observations were compiled. Treatment and control sample groups () were constructed from core lineups of players on the streaking batter’s team. The percentile method bootstrap was used to calculate confidence intervals for statistics representing differences in the mean distributions of two batting statistics between groups. Batters in the treatment group (hot streak active) showed statistically significant improvements in hitting performance, as compared against the control. Mean for the treatment group was found to be to percentage points higher during hot streaks (mean difference increased points), while the batting heat index introduced here was observed to increase by points. For each performance statistic, the null hypothesis was rejected at the significance level. We conclude that the evidence suggests the potential existence of a “statistical contagion effect”. Psychological mechanisms essential to the empirical results are suggested, as several studies from the scientific literature lend credence to contagious phenomena in sports. Causal inference from these results is difficult, but we suggest and discuss several latent variables that may contribute to the observed results, and offer possible directions for future research. PMID:23251507

  8. Marek’s disease virus and skin interactions

    PubMed Central

    2014-01-01

    Marek’s disease virus (MDV) is a highly contagious herpesvirus which induces T-cell lymphoma in the chicken. This virus is still spreading in flocks despite forty years of vaccination, with important economical losses worldwide. The feather follicles, which anchor feathers into the skin and allow their morphogenesis, are considered as the unique source of MDV excretion, causing environmental contamination and disease transmission. Epithelial cells from the feather follicles are the only known cells in which high levels of infectious mature virions have been observed by transmission electron microscopy and from which cell-free infectious virions have been purified. Finally, feathers harvested on animals and dust are today considered excellent materials to monitor vaccination, spread of pathogenic viruses, and environmental contamination. This article reviews the current knowledge on MDV-skin interactions and discusses new approaches that could solve important issues in the future. PMID:24694064

  9. Emergence of West Nile Virus Lineage 2 in Europe: A Review on the Introduction and Spread of a Mosquito-Borne Disease

    PubMed Central

    Hernández-Triana, Luis M.; Jeffries, Claire L.; Mansfield, Karen L.; Carnell, George; Fooks, Anthony R.; Johnson, Nicholas

    2014-01-01

    West Nile virus (WNV) is transmitted by mosquitoes and causes fever and encephalitis in humans, equines, and occasionally wild birds. The virus was first isolated in sub-Saharan Africa where it is endemic. WNV lineage 1 has been responsible for repeated disease outbreaks in the countries of the Mediterranean basin over the past 50?years. This lineage was also introduced into North America in 1999 causing widespread human, equine, and avian mortality. WNV lineage 2, the first WNV lineage to be isolated, was believed to be restricted to sub-Saharan Africa causing a relatively mild fever in humans. However, in 2004, an investigation in Hungary of a case of encephalitis in a wild goshawk (Accipiter gentiles) resulted in the isolation of WNV lineage 2. During the summer of 2004, and in subsequent years, the virus appeared to spread locally throughout Hungary and into neighboring Austria. Subsequently, WNV lineage 2 emerged in Greece in 2010 and in Italy in 2011, involving outbreaks on the Italian mainland and Sardinia. Further spread through the Balkan countries is also suspected. Whole genome sequencing has confirmed that the virus responsible for the outbreaks in Greece and Italy was almost identical to that isolated in Hungary. However, unlike the outbreaks in Hungary, the burden of disease in Mediterranean countries has fallen upon the human population with numerous cases of West Nile fever and a relatively higher mortality rate than in previous outbreaks. The emergence of WNV lineage 2 in Europe, its over-wintering and subsequent spread over large distances illustrates the repeated threat of emerging mosquito-borne diseases. This article will review the emergence of WNV lineage 2 in Europe; consider the pathways for virus spread and the public health implications for the continent. PMID:25538937

  10. 76 FR 31220 - Importation of Horses From Contagious Equine Metritis-Affected Countries

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ...APHIS-2008-0112] RIN 0579-AD31 Importation of Horses From Contagious Equine Metritis-Affected...regulations regarding the importation of horses from countries affected with contagious...certification requirement for imported horses 731 days of age or less and adding...

  11. [Cerebral nerves - perineural tumor spread].

    PubMed

    Bisdas, S; Mack, M G

    2009-07-01

    Perineural tumor spread in the course of head and neck tumors is a form of metastatic disease in which the tumor disseminates centrifugally or centripetally along the nerve to (non)contiguous regions. Perineural tumor spread is a potentially devastating complication and has a high impact on the therapeutic management and overall prognosis. In a large proportion of patients the disease remains asymptomatic and imaging (especially MRI) plays a crucial role in the detection of lesions. Familiarity with the pertinent anatomy, knowledge of the common spread pathways and an appropriate imaging strategy allow detection of the perineural spread of the disease in the majority of the cases. PMID:19424678

  12. Modelling spread of foot-and-mouth disease in wild white-tailed deer and feral pig populations using a geographic-automata model and animal distributions.

    PubMed

    Ward, Michael P; Laffan, Shawn W; Highfield, Linda D

    2009-09-01

    We investigated how the size and distribution of wild deer and feral pigs - species that might act as potential foot-and-mouth disease (FMD) virus maintenance hosts - might affect the persistence and spread of FMD. We used a susceptible-latent-infected-recovered geographic-automata model and spatially referenced data from southern Texas, USA. Within this study area, 100 locations were randomly selected and FMD virus spread was simulated (50 simulations each) at each location. As expected, the predicted sizes (km(2)) of the wild deer outbreaks were highly correlated (r(SP)>0.95) with the number of deer at incursion locations, the total number of deer within 2 km of incursion locations, and the minimum and maximum deer herd size within 2 km of incursion locations. However, the predicted sizes of the feral pig outbreaks were only moderately correlated (r(SP) 0.63-0.67) with the total, maximum and variance of the number of feral pigs within 2 km of incursion locations. Lack of continuity within the feral pig herd distribution across the landscape makes predicting disease spread more difficult than for deer, a more homogenously distributed species. When assessing the potential of wild and feral animal species at a locality to act as maintenance hosts of FMD virus, estimates of the population size and distribution might serve as a useful indicator of potential outbreaks in some circumstances. PMID:19515439

  13. TDP-43 and ubiquitinated cytoplasmic aggregates in sporadic ALS are low frequency and widely distributed in the lower motor neuron columns independent of disease spread.

    PubMed

    Bodansky, Aaron; Kim, Jae Mun Hugo; Tempest, Lynne; Velagapudi, Amit; Libby, Ryan; Ravits, John

    2010-05-01

    Ubiqitinated and TDP-43 immunoreactive cytoplasmic aggregates are hallmark features of ALS molecular pathology. Since clinically most ALS begins focally and advances contiguously, it is important to characterize their distribution. Our objective was to determine the extent and distribution of TDP-43 immunoreactive aggregates in the lower motor neuron columns as a function of disease onset, and to correlate ubiquitinated with TDP-43 aggregates in the lumbar region. We examined TDP-43 cytoplasmic aggregates at four separate neuraxis levels - hypoglossal nucleus and cervical, thoracic, and lumbar anterior horns - in five controls and 20 sporadic ALS nervous systems from patients whose disease began in various sites, i.e. five bulbar, five arm, five trunk, and five leg onsets. We correlated ubiquitinated to TDP-43 aggregates on adjacent histological sections for the lumbar regions. We found that TDP-43 cytoplasmic aggregates are seen in about 8% of motor neurons but there is marked variability between nervous systems, ranging from 0.4% to 20.6%. The aggregates are uniformly distributed within individual nervous systems. There is no obvious correlation between site of disease onset and rate of spread. Almost all ubiquitinated aggregates correlate to TDP-43 aggregates. Thus, TDP-43 immunoreactive cytoplasmic aggregates have a low overall average frequency that does not correlate with either disease course or clinical spread and is the prime ubiquitinated protein. PMID:20225928

  14. Bayesian Biosurveillance of Disease Outbreaks Gregory F. Cooper

    E-print Network

    Wong, Weng-Keen

    Bayesian networks to model spatio-temporal patterns of a non-contagious disease (respiratory anthrax) or bioterrorist- induced (e.g., anthrax and smallpox), is a critically important problem today. We need to detect of people. We concentrate on modeling non-contagious outbreak diseases, such as airborne anthrax or West

  15. Quantitative risk assessment of entry of contagious bovine pleuropneumonia through live cattle imported from northwestern Ethiopia.

    PubMed

    Woube, Yilkal Asfaw; Dibaba, Asseged Bogale; Tameru, Berhanu; Fite, Richard; Nganwa, David; Robnett, Vinaida; Demisse, Amsalu; Habtemariam, Tsegaye

    2015-11-01

    Contagious bovine pleuropneumonia (CBPP) is a highly contagious bacterial disease of cattle caused by Mycoplasma mycoides subspecies mycoides small colony (SC) bovine biotype (MmmSC). It has been eradicated from many countries; however, the disease persists in many parts of Africa and Asia. CBPP is one of the major trade-restricting diseases of cattle in Ethiopia. In this quantitative risk assessment the OIE concept of zoning was adopted to assess the entry of CBPP into an importing country when up to 280,000 live cattle are exported every year from the northwestern proposed disease free zone (DFZ) of Ethiopia. To estimate the level of risk, a six-tiered risk pathway (scenario tree) was developed, evidences collected and equations generated. The probability of occurrence of the hazard at each node was modelled as a probability distribution using Monte Carlo simulation (@RISK software) at 10,000 iterations to account for uncertainty and variability. The uncertainty and variability of data points surrounding the risk estimate were further quantified by sensitivity analysis. In this study a single animal destined for export from the northwestern DFZ of Ethiopia has a CBPP infection probability of 4.76×10(-6) (95% CI=7.25×10(-8) 1.92×10(-5)). The probability that at least one infected animal enters an importing country in one year is 0.53 (90% CI=0.042-0.97). The expected number of CBPP infected animals exported any given year is 1.28 (95% CI=0.021-5.42). According to the risk estimate, an average of 2.73×10(6) animals (90% CI=10,674-5.9×10(6)) must be exported to get the first infected case. By this account it would, on average, take 10.15 years (90% CI=0.24-23.18) for the first infected animal to be included in the consignment. Sensitivity analysis revealed that prevalence and vaccination had the highest impact on the uncertainty and variability of the overall risk. PMID:26427634

  16. Recombinant newcastle disease vaccines: risk for recombination, reversion to virulence, and spread in non-target species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newcastle disease virus (NDV) infection of chickens causes a range of clinical disease ranging from asymptomatic infection to severe disease with high mortality. When an outbreak of the virulent form of the virus occurs in poultry, the country is obligated to report it to the World Organization for...

  17. Recombinant Newcastle disease vaccines: risk for recombination, reversion to virulence, and spread in non-target species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newcastle disease (ND), caused by Newcastle disease virus (NDV), is one of the most important diseases of poultry and causes significant economic losses to the poultry industry worldwide. Vaccination is the main form of control of ND and it has been practiced for more than 60 years with billions of...

  18. Genetic diversity and mutation of avian paramyxovirus serotype 1 (Newcastle disease virus) in wild birds and evidence for intercontinental spread

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian paramyxovirus serotype 1 (APMV-1), or Newcastle disease virus, is the causative agent of Newcastle disease (ND), one of the most economically important diseases for poultry production worldwide and a cause of periodic epornitics in wild birds in North America. In this study, we explored the ge...

  19. Use of Penicillin and Streptomycin to Reduce Spread of Bacterial Coldwater Disease II: Efficacy of Using Antibiotics in Diluents and During Water Hardening.

    PubMed

    Oplinger, Randall W; Wagner, Eric J; Cavender, Wade

    2015-03-01

    Bacterial coldwater disease, caused by Flavobacterium psychrophilum, has lead to the loss of significant numbers of hatchery-reared salmonids. The bacteria can be spread from parent to progeny within contaminated sperm and ovarian fluid and can enter the egg during fertilization. The addition of antibiotics to diluents and water-hardening solutions could prevent the spread of the disease. In separate trials, a mixture of 0.197 mg/mL penicillin plus 0.313 mg/mL streptomycin was added to both a 0.5% sodium chloride fertilization diluent and hatchery well water during hardening. Tests showed that the addition of the antibiotics to the diluent and during up to 60 min of water hardening had no effect on the eye-up, hatch and deformity rates of Rainbow Trout Oncorhynchus mykiss eggs compared with the nonantibiotic-treated controls. Also, significant reductions in the prevalence of F. psychrophilum on the surface and inside eggs were observed when compared with controls. These results indicate that the addition of penicillin and streptomycin to diluents and during water hardening can prevent the vertical transmission of bacterial coldwater disease. PMID:25581260

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

    PubMed Central

    Cenciarelli, Orlando; Pietropaoli, Stefano; Carestia, Mariachiara; D'Amico, Fabrizio; Sassolini, Alessandro; Di Giovanni, Daniele; Rea, Silvia; Gabbarini, Valentina; Tamburrini, Annalaura; Palombi, Leonardo; Bellecci, Carlo; Gaudio, Pasquale

    2015-01-01

    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. PMID:25852754

  1. A Rational Approach to Estimating the Surgical Demand Elasticity Needed to Guide Manpower Reallocation during Contagious Outbreaks

    PubMed Central

    Tsao, Hsiao-Mei; Sun, Ying-Chou; Liou, Der-Ming

    2015-01-01

    Background Emerging infectious diseases continue to pose serious threats to global public health. So far, however, few published study has addressed the need for manpower reallocation needed in hospitals when such a serious contagious outbreak occurs. Aim To quantify the demand elasticity of the major surgery types in order to guide future manpower reallocation during contagious outbreaks. Materials and Methods Based on a nationwide research database in Taiwan, we extracted the monthly volumes of major surgery types for the period 1998–2003, which covered the SARS period, in order to carry out a time series analysis. The demand elasticity of each surgery type was then estimated by autoregressive integrated moving average (ARIMA) analysis. Results During the study period, the surgical volumes of most selected surgery types either increased or remained steady. We categorized these surgery types into low-, moderate- and high-elastic groups according to their demand elasticity. Appendectomy, ‘open reduction of fracture with internal fixation’ and ‘free skin graft’ were in the low demand elasticity group. Transurethral prostatectomy and extracorporeal shockwave lithotripsy (ESWL) were in the high demand elasticity group. The manpower of the departments carrying out the surgeries with low demand elasticity should be maintained during outbreaks. In contrast, departments in charge of surgeries mainly with high demand elasticity, like urology departments, may be in a position to have part of their staff reallocated. Conclusions Taking advantage of the demand variation during the SARS period in 2003, we adopted the concept of demand elasticity and used a time series approach to figure out an effective index of demand elasticity for various types of surgery that could be used as a rational reference to carry out manpower reallocation during contagious outbreak situations. PMID:25837596

  2. The impact of potential mitigation strategies on the predicted spread of foot and mouth disease in white-tailed deer in south Texas.

    PubMed

    Highfield, Linda D; Ward, Michael P; Laffan, Shawn W; Norby, Bo; Wagner, G Gale

    2010-05-01

    The United States has been free of FMD since the 1920s. Faced with an incursion of FMD virus that might involve wildlife species, it is crucial that appropriate mitigation strategies be applied rapidly to control the disease. Disease spread models can be used to evaluate the design of optimal strategies. Using a previously developed susceptible-infected-recovered geographic automata model (Sirca) to simulate the spread of FMD through white-tailed deer populations in south Texas, we conducted a series of experiments to determine how pre-emptive mitigation strategies applied to white-tailed deer populations might impact the predicted magnitude and distribution of outbreaks following FMD virus incursion. Based on previously derived deer distributions in the two ecoregions found within the study area, simulated outbreaks were evaluated by comparing the median number of deer predicted to be infected and the median area predicted affected for a baseline scenario and 3 mitigation strategies: targeted cull, random cull and targeted depopulation buffer. Substantial differences were observed in the predicted magnitude of outbreaks both by mitigation strategy and by ecoregion: depending on the ecoregion, the creation of a targeted depopulation buffer could reduce the number of deer predicted infected by up to 52%, and the area affected by up to 31%. Results suggest that the outcome of an FMD incursion that involves wildlife species, such as white-tailed deer in south Texas, might depend on both where the incursion occurs and the type of pre-emptive mitigation strategy applied. PMID:20181400

  3. Evaluation of strategies for the eradication of Pseudorabies virus (Aujeszky's disease) in commercial swine farms in Chiang-Mai and Lampoon Provinces, Thailand, using a simulation disease spread model.

    PubMed

    Ketusing, N; Reeves, A; Portacci, K; Yano, T; Olea-Popelka, F; Keefe, T; Salman, M

    2014-04-01

    Several strategies for eradicating Pseudorabies virus (Aujeszky's disease) in Chiang-Mai and Lampoon Provinces, Thailand, were compared using a computer simulation model, the North American Animal Disease Spread Model (NAADSM). The duration of the outbreak, the number of affected herds and the number of destroyed herds were compared during these simulated outbreaks. Depopulation, zoning for restricted movement and improved detection and vaccination strategies were assessed. The most effective strategies to eradicate Pseudorabies as per the findings from this study are applying depopulation strategies with MOVEMENT RESTRICTIONS in 3-, 8- and 16-km ZONES surrounding infected herds and enhancing the eradication with vaccination campaign on 16-km radius surrounding infected herds. PMID:23033968

  4. How Is Mono Spread?

    MedlinePLUS

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español ... Guy's Guide to Body Image How Is Mono Spread? KidsHealth > Teens > Q& ...

  5. Prevalence of Rabies in Various Species in Yemen and Risk Factors Contributing to the Spread of the Disease

    PubMed Central

    Al-Shamahy, Hassan A.; Sunhope, Ameera; Al-Moyed, Khaled A.

    2013-01-01

    Objectives: This study aimed to describe for the first time the prevalence of the passively-reported rabies virus among different domestic and wild animals submitted to the Central Veterinary Laboratory from various areas in Yemen, and to study prevalence proportion ratios (PPR) that contributed to the spread of rabies among animals, and its transmission to humans. Methods: A brain sample was obtained from each of the 180 animals and tested for rabies virus by a direct fluorescent antibody test. Results: Out of the total number of animals involved in attacks on humans, 63.3 % were positive for rabies. Of these, dogs were the main animal involved in attacks with a percentage of 92%, of which 62.7% were positive for rabies. Of animals involved in attacks, 70.6% were males of which 60.6% were positive, and 29.4% were females of which 69.8% were positive. Males comprised 68.9% of the total human individuals attacked, of whom 62.9% were attacked by rabies-positive animals. The significant risk factors that contributed to the spread of rabies in general included the presence of poultry carcasses and other waste in the vicinity of the attacks (PPR = 9.5) with a percentage of 84.8%, followed by the time of year, in particular school vacations (PPR = 3.8) with a percentage of 78%. Conclusion: Rabies is endemic in Yemen with a very high rabies-positive rate for animals involved in attacks, particularly for stray male dogs. Male children were most often involved in attacks by rabies-positive animals. The presence of food waste (particularly poultry carcasses) and school vacation periods were found to correlate significantly with increased risk for human exposure to rabies. PMID:23984026

  6. Lumpy Skin Disease in Iraq: Study of the Disease Emergence.

    PubMed

    Al-Salihi, K A; Hassan, I Q

    2015-10-01

    This study intends to report the first emergence of lumpy skin disease (LSD) in Iraq, in addition to describing its related clinical signs. In August 2013, 21 cases of four outbreaks developed clinical signs suggestive of LSD in the Nineveh (Mosul) and Baghdad Governorates, which were considered as the first infected foci of LSD in Iraq. The disease was diagnosed tentatively, on the basis of clinical signs and epidemiological features, and it was confirmed as positive by the polymerase chain reaction and histopathological features. In September 2013, eight new outbreaks of LSD also appeared in Baghdad and Nineveh. In 2014, the disease spread rapidly to the governorates of Kirkuk, Salah Al-Din, Al-Anbar, Diyala, Wasit, Babil, Karbala, Najaf, Al-Diwaniyah, Muthanna, Maysan, DhiQar and Basra. The total number of infected cows and calves reported was 7396 and 227, respectively. The apparent morbidity and mortality rates were 9.11% and 0.51%, respectively, while the apparent case-fatality rate was 5.56%. Skin nodules, anorexia, reduce in milk production and decrease in bodyweight were the common clinical signs. Moreover, myiasis and mastitis were seen as complications in some infected animals. Attempts were made to stop the distribution of the disease including quarantine and treatment, control over animal movement and arthropod control. Ring vaccination was used in a 10 km radius zone around the outbreak with live sheep pox vaccine. The highly contagious transboundary nature of the LSD, its endemic distribution in the Iraqi neighbouring countries, and the current armed conflict in the area were the possible factors for the disease being introduced into the country. LSD had spread through the Middle East and Gulf peninsula and could be a cause of danger to the rest of Asia and Europe. International precaution, cooperation and exchange of information could guarantee the prevention and further spread of the disease to the rest of Asia and Europe. PMID:26105081

  7. Comparative sequence analysis of a highly oncogenic but horizontal spread-defective clone of Marek's disease virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease virus (MDV) is a cell-associated alphaherpesvirus that induces rapid-onset T-cell lymphomas in poultry. MDV isolates vary greatly in pathogenicity. While some of the strains such as CVI988 are non-pathogenic and are used as vaccines, others such as RB1B are highly oncogenic. Compa...

  8. Comparative sequence analysis of a highly oncogenic but horizontal spread-deficient clone of Marek's disease virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease virus (MDV) is a cell-associated alphaherpesvirus that induces T-cell lymphomas in poultry. MDV isolates vary greatly in pathogenicity. While some are non-pathogenic and are used as vaccines, others such as RB-1B are highly oncogenic. Comparison of the genome sequences of phenotypica...

  9. The Science, Spread and Therapy of HIV Disease. Everything You Need To Know, but Had No Idea Who To Ask.

    ERIC Educational Resources Information Center

    DiSpezio, Michael A.

    This book uses a question-and-answer format to provide information on the Human Immunodeficiency Virus (HIV) and the disease caused by infection from the virus, Acquired Immune Deficiency Syndrome (AIDS). Topics covered include: (1) "Outbreak," which discusses the history of the AIDS outbreak including early theories about the causes of AIDS and…

  10. Extracellular vesicles--Their role in the packaging and spread of misfolded proteins associated with neurodegenerative diseases.

    PubMed

    Coleman, Bradley M; Hill, Andrew F

    2015-04-01

    Many cell types, including neurons, are known to release small membranous vesicles known as exosomes. In addition to their protein content these vesicles have recently been shown to contain messenger RNA (mRNA) and micro RNA (miRNA) species. Roles for these vesicles include cell-cell signalling, removal of unwanted proteins, and transfer of pathogens (including prion-like misfolded proteins) between cells, such as infectious prions. Prions are the infectious particles that are responsible for transmissible neurodegenerative diseases such as Creutzfeldt-Jakob disease (CJD) of humans or bovine spongiform encephalopathy (BSE) of cattle. Exosomes are also involved in processing the amyloid precursor protein (APP), which is associated with Alzheimer's disease (AD). As exosomes can be isolated from circulating fluids such as serum, urine, and cerebrospinal fluid (CSF), they provide a potential source of biomarkers for neurological conditions. Here, we review the roles these vesicles play in neurodegenerative disease and highlight their potential in diagnosing these disorders through analysis of their RNA content. PMID:25704308

  11. The impact of information spreading on disease dynamics. Comment on "Coupled disease-behavior on complex networks: A review" by Z. Wang et al.

    NASA Astrophysics Data System (ADS)

    Rodrigues, Francisco A.

    2015-12-01

    Epidemic modeling is fundamental to our understanding of the disease dynamics [1]. Theoretical models have allowed the development of methods for immunization and vaccination policies, being used for disease forecast and control [1-3]. Typically, disease propagation is modeled as a stochastic process in which an infectious agent is transmitted from an infected individual to a susceptible subject via the connection between them [4]. The initial models to describe the disease propagation considered homogeneous-mixing compartmental models [2], which assume that all subjects have identical probabilities of interaction. In this way, the network of contacts is a fully connected graph wherein the interaction might happen between every pair of individuals [2].

  12. Contagious parthenogenesis, automixis, and a sex determination meltdown.

    PubMed

    Engelstädter, Jan; Sandrock, Christoph; Vorburger, Christoph

    2011-02-01

    Because of the twofold cost of sex, genes conferring asexual reproduction are expected to spread rapidly in sexual populations. However, in reality this simple prediction is often confounded by several complications observed in natural systems. Motivated by recent findings in the Cape honey bee and in the parasitoid wasp Lysiphlebus fabarum, we explore through mathematical models the spread of a recessive, parthenogenesis inducing allele in a haplodiploid population. The focus of these models is on the intricate interactions between the mode of parthenogenesis induction through automixis and complementary sex determination (CSD) systems. These interactions may result in asexual production of diploid male offspring and the spread of the parthenogenesis-inducing allele through these males. We demonstrate that if parthenogenetic females produce a substantial proportion of male offspring, this may prevent the parthenogenesis-inducing allele from spreading. However, this effect is weakened if these diploid males are at least partially fertile. We also predict a degradation of multilocus CSD systems during the spread of parthenogenesis, following which only a single polymorphic CSD locus is maintained. Finally, based on empirical parameter estimates from L. fabarum we predict that male production in parthenogens is unlikely to prevent the eventual loss of sexual reproduction in this system. PMID:21029077

  13. Isothermal loop-mediated amplification (lamp) for diagnosis of contagious bovine pleuro-pneumonia

    PubMed Central

    2013-01-01

    Background Contagious Bovine Pleuropneumonia (CBPP) is the most important chronic pulmonary disease of cattle on the African continent causing severe economic losses. The disease, caused by infection with Mycoplasma mycoides subsp. mycoides is transmitted by animal contact and develops slowly into a chronic form preventing an early clinical diagnosis. Because available vaccines confer a low protection rate and short-lived immunity, the rapid diagnosis of infected animals combined with traditional curbing measures is seen as the best way to control the disease. While traditional labour-intensive bacteriological methods for the detection of M. mycoides subsp. mycoides have been replaced by molecular genetic techniques in the last two decades, these latter approaches require well-equipped laboratories and specialized personnel for the diagnosis. This is a handicap in areas where CBPP is endemic and early diagnosis is essential. Results We present a rapid, sensitive and specific diagnostic tool for M. mycoides subsp. mycoides detection based on isothermal loop-mediated amplification (LAMP) that is applicable to field conditions. The primer set developed is highly specific and sensitive enough to diagnose clinical cases without prior cultivation of the organism. The LAMP assay detects M. mycoides subsp. mycoides DNA directly from crude samples of pulmonary/pleural fluids and serum/plasma within an hour using a simple dilution protocol. A photometric detection of LAMP products allows the real-time visualisation of the amplification curve and the application of a melting curve/re-association analysis presents a means of quality assurance based on the predetermined strand-inherent temperature profile supporting the diagnosis. Conclusion The CBPP LAMP developed in a robust kit format can be run on a battery-driven mobile device to rapidly detect M. mycoides subsp. mycoides infections from clinical or post mortem samples. The stringent innate quality control allows a conclusive on-site diagnosis of CBPP such as during farm or slaughter house inspections. PMID:23710975

  14. Contagious seed dispersal beneath heterospecific fruiting trees and its consequences.

    SciTech Connect

    Kwit, Charles; Levey, Douglas, J.; Greenberg, Cathyrn, H.

    2004-05-03

    Kwit, Charles, D.J. Levey and Cathryn H. Greenberg. 2004. Contagious seed dispersal beneath heterospecific fruiting trees and its consequences. Oikos. 107:303-308 A n hypothesized advantage of seed dispersal is avoidance of high per capita mortality (i.e. density-dependent mortality) associated with dense populations of seeds and seedlings beneath parent trees. This hypothesis, inherent in nearly all seed dispersal studies, assumes that density effects are species-specific. Yet because many tree species exhibit overlapping fruiting phenologies and share dispersers, seeds may be deposited preferentially under synchronously fruiting heterospecific trees, another location where they may be particularly vulnerable to mortality, in this case by generalist seed predators. We demonstrate that frugivores disperse higher densities of Cornus florida seeds under fruiting (female) I lex opaca trees than under non-fruiting (male) I lex trees in temperate hardwood forest settings in South Carolina, U SA . To determine if density of Cornus and/or I lex seeds influences survivorship of dispersed Cornus seeds, we followed the fates of experimentally dispersed Cornus seeds in neighborhoods of differing, manipulated background densities of Cornus and I lex seeds. We found that the probability of predation on dispersed Cornus seeds was a function of both Cornus and I lex background seed densities. H igher densities of I lex seeds negatively affected Cornus seed survivorship, and this was particularly evident as background densities of dispersed Cornus seeds increased. These results illustrate the importance of viewing seed dispersal and predation in a community context, as the pattern and intensity of density-dependent mortality may not be solely a function of conspecific densities.

  15. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 false Appearance of disease among horses in quarantine. 93.313...CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the...

  16. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false Appearance of disease among horses in quarantine. 93.313...CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the...

  17. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false Appearance of disease among ruminants in quarantine. 93... Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  18. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false Appearance of disease among horses in quarantine. 93.313...CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the...

  19. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 false Appearance of disease among ruminants in quarantine. 93... Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  20. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 false Appearance of disease among ruminants in quarantine. 93... Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  1. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 false Appearance of disease among swine in quarantine. 93.515...CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the...

  2. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false Appearance of disease among ruminants in quarantine. 93... Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  3. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 false Appearance of disease among swine in quarantine. 93.515...CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the...

  4. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false Appearance of disease among swine in quarantine. 93.515...CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the...

  5. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 false Appearance of disease among horses in quarantine. 93.313...CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the...

  6. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false Appearance of disease among horses in quarantine. 93.313...CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the...

  7. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false Appearance of disease among poultry in quarantine. 93.213... Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the...

  8. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 false Appearance of disease among poultry in quarantine. 93.213... Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the...

  9. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false Appearance of disease among poultry in quarantine. 93.213... Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the...

  10. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 false Appearance of disease among poultry in quarantine. 93.213... Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the...

  11. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false Appearance of disease among poultry in quarantine. 93.213... Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the...

  12. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false Appearance of disease among ruminants in quarantine. 93... Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  13. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false Appearance of disease among swine in quarantine. 93.515...CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the...

  14. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false Appearance of disease among swine in quarantine. 93.515...CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the...

  15. Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy

    PubMed Central

    Romero, Teresa; Konno, Akitsugu; Hasegawa, Toshikazu

    2013-01-01

    In humans, the susceptibility to yawn contagion has been theoretically and empirically related to our capacity for empathy. Because of its relevance to evolutionary biology, this phenomenon has been the focus of recent investigations in non-human species. In line with the empathic hypothesis, contagious yawning has been shown to correlate with the level of social attachment in several primate species. Domestic dogs (Canis familiaris) have also shown the ability to yawn contagiously. To date, however, the social modulation of dog contagious yawning has received contradictory support and alternative explanations (i.e., yawn as a mild distress response) could explain positive evidence. The present study aims to replicate contagious yawning in dogs and to discriminate between the two possible mediating mechanisms (i.e., empathic vs. distress related response). Twenty-five dogs observed familiar (dog’s owner) and unfamiliar human models (experimenter) acting out a yawn or control mouth movements. Concurrent physiological measures (heart rate) were additionally monitored for twenty-one of the subjects. The occurrence of yawn contagion was significantly higher during the yawning condition than during the control mouth movements. Furthermore, the dogs yawned more frequently when watching the familiar model than the unfamiliar one demonstrating that the contagiousness of yawning in dogs correlated with the level of emotional proximity. Moreover, subjects’ heart rate did not differ among conditions suggesting that the phenomenon of contagious yawning in dogs is unrelated to stressful events. Our findings are consistent with the view that contagious yawning is modulated by affective components of the behavior and may indicate that rudimentary forms of empathy could be present in domesticated dogs. PMID:23951146

  16. Small-scale pig farmers’ behavior, silent release of African swine fever virus and consequences for disease spread

    PubMed Central

    Costard, Solenne; Zagmutt, Francisco J.; Porphyre, Thibaud; Pfeiffer, Dirk Udo

    2015-01-01

    The expanding distribution of African swine fever (ASF) is threatening the pig industry worldwide. Most outbreaks occur in backyard and small-scale herds, where poor farmers often attempt to limit the disease’s economic consequences by the emergency sale of their pigs. The risk of African swine fever virus (ASFV) release via this emergency sale was investigated. Simulation modeling was used to study ASFV transmission in backyard and small-scale farms as well as the emergency sale of pigs, and the potential impact of improving farmers and traders’ clinical diagnosis ability–its timeliness and/or accuracy–was assessed. The risk of ASFV release was shown to be high, and improving farmers’ clinical diagnosis ability does not appear sufficient to effectively reduce this risk. Estimates obtained also showed that the distribution of herd size within the backyard and small-scale sectors influences the relative contribution of these farms to the risk of release of infected pigs. These findings can inform surveillance and control programs. PMID:26610850

  17. An investigation into the source and spread of foot and mouth disease virus from a wildlife conservancy in Zimbabwe.

    PubMed

    Hargreaves, S K; Foggin, C M; Anderson, E C; Bastos, A D S; Thomson, G R; Ferris, N P; Knowles, N J

    2004-12-01

    African buffalo were introduced into a wildlife conservancy in the southeast of Zimbabwe in an effortto increase the conservancy's economic viability, which is primarily based on eco-tourism. The buffalo were infected with SAT serotypes (SAT-1, SAT-2 and SAT-3) of foot and mouth disease (FMD) virus, and in order to isolate the conservancy and prevent the transmission of FMD to adjacent populations of domestic livestock, the conservancy was surrounded by a double-fence system, 1.8 m in height. The intention was to prevent the movement of both wildlife and domestic animals across the perimeter. However, two years after the buffalo were introduced, FMD occurred in cattle farmed just outside of the conservancy. Using serological and molecular diagnostic tests, epidemiological investigations showed that it was most likely that antelope (impala or kudu), infected through contact with the buffalo herd within the conservancy, had jumped over the fence and transmitted the virus to the cattle. PMID:15861873

  18. Immunoglobulin epitope spreading and autoimmune disease after peptide immunization: Sm B/B'-derived PPPGMRPP and PPPGIRGP induce spliceosome autoimmunity.

    PubMed

    James, J A; Gross, T; Scofield, R H; Harley, J B

    1995-02-01

    Autoantibodies from many patients with systemic lupus erythematosus bind the Sm autoantigen B/B' polypeptide. The binding of serial serum specimens to the 233 overlapping octapeptides of Sm B/B' have shown that of the B/B'-derived octapeptides, PPPGMRPP and PPPGIRGP are early targets of the autoimmune response in some lupus patients. Rabbits immunized with PPPGMRPP and PPPGIRGP develop antibodies which not only bind these octapeptides, but also subsequently bind many other octapeptides of Sm B/B'. Eventually, the rabbits immunized with one octapeptide develop autoantibodies that bind other spliceosomal proteins including D, 70K, A, and C. Any mechanisms that operate to maintain tolerance or anergy for the spliceosome are thus overcome. Features considered typical of human systemic lupus erythematosus are also found in these peptide-immunized animals, such as antinuclear antibodies, anti-Sm precipitins, anti-double-stranded DNA, thrombocytopenia, seizures, and proteinuria. This disease model provides access to a mechanism for the development of humoral autoimmunity and may provide a basis to explain the immunopathogenesis of lupus in humans. PMID:7530756

  19. Interspecific competition in honeybee intracellular gut parasites is asymmetric and favours the spread of an emerging infectious disease

    PubMed Central

    Natsopoulou, Myrsini E.; McMahon, Dino P.; Doublet, Vincent; Bryden, John; Paxton, Robert J.

    2015-01-01

    There is increasing appreciation that hosts in natural populations are subject to infection by multiple parasite species. Yet the epidemiological and ecological processes determining the outcome of mixed infections are poorly understood. Here, we use two intracellular gut parasites (Microsporidia), one exotic and one co-evolved in the western honeybee (Apis mellifera), in an experiment in which either one or both parasites were administered either simultaneously or sequentially. We provide clear evidence of within-host competition; order of infection was an important determinant of the competitive outcome between parasites, with the first parasite significantly inhibiting the growth of the second, regardless of species. However, the strength of this ‘priority effect’ was highly asymmetric, with the exotic Nosema ceranae exhibiting stronger inhibition of Nosema apis than vice versa. Our results reveal an unusual asymmetry in parasite competition that is dependent on order of infection. When incorporated into a mathematical model of disease prevalence, we find asymmetric competition to be an important predictor of the patterns of parasite prevalence found in nature. Our findings demonstrate the wider significance of complex multi-host–multi-parasite interactions as drivers of host–pathogen community structure. PMID:25429014

  20. Small-scale pig farmers' behavior, silent release of African swine fever virus and consequences for disease spread.

    PubMed

    Costard, Solenne; Zagmutt, Francisco J; Porphyre, Thibaud; Pfeiffer, Dirk Udo

    2015-01-01

    The expanding distribution of African swine fever (ASF) is threatening the pig industry worldwide. Most outbreaks occur in backyard and small-scale herds, where poor farmers often attempt to limit the disease's economic consequences by the emergency sale of their pigs. The risk of African swine fever virus (ASFV) release via this emergency sale was investigated. Simulation modeling was used to study ASFV transmission in backyard and small-scale farms as well as the emergency sale of pigs, and the potential impact of improving farmers and traders' clinical diagnosis ability-its timeliness and/or accuracy-was assessed. The risk of ASFV release was shown to be high, and improving farmers' clinical diagnosis ability does not appear sufficient to effectively reduce this risk. Estimates obtained also showed that the distribution of herd size within the backyard and small-scale sectors influences the relative contribution of these farms to the risk of release of infected pigs. These findings can inform surveillance and control programs. PMID:26610850

  1. Animal Ownership and Touching Enrich the Context of Social Contacts Relevant to the Spread of Human Infectious Diseases

    PubMed Central

    Kifle, Yimer Wasihun; Goeyvaerts, Nele; Van Kerckhove, Kim; Willem, Lander; Faes, Christel; Leirs, Herwig; Hens, Niel; Beutels, Philippe

    2015-01-01

    Many human infectious diseases originate from animals or are transmitted through animal vectors. We aimed to identify factors that are predictive of ownership and touching of animals, assess whether animal ownership influences social contact behavior, and estimate the probability of a major zoonotic outbreak should a transmissible influenza-like pathogen be present in animals, all in the setting of a densely populated European country. A diary-based social contact survey (n = 1768) was conducted in Flanders, Belgium, from September 2010 until February 2011. Many participants touched pets (46%), poultry (2%) or livestock (2%) on a randomly assigned day, and a large proportion of participants owned such animals (51%, 15% and 5%, respectively). Logistic regression models indicated that larger households are more likely to own an animal and, unsurprisingly, that animal owners are more likely to touch animals. We observed a significant effect of age on animal ownership and touching. The total number of social contacts during a randomly assigned day was modeled using weighted-negative binomial regression. Apart from age, household size and day type (weekend versus weekday and regular versus holiday period), animal ownership was positively associated with the total number of social contacts during the weekend. Assuming that animal ownership and/or touching are at-risk events, we demonstrate a method to estimate the outbreak potential of zoonoses. We show that in Belgium animal-human interactions involving young children (0–9 years) and adults (25–54 years) have the highest potential to cause a major zoonotic outbreak. PMID:26193480

  2. BRCA1 loss pre-existing in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood

    SciTech Connect

    Bednarz, Natalia; Eltze, Elke; Semjonow, Axel; Rink, Michael; Andreas, Antje; Mulder, Lennart; Hannemann, Juliane; Fisch, Margit; Pantel, Klaus; Weier, Heinz-Ulrich G.; Bielawski, Krzysztof P.; Brandt, Burkhard

    2010-03-19

    A recent study concluded that serum prostate specific antigen (PSA)-based screening is beneficial for reducing the lethality of PCa, but was also associated with a high risk of 'overdiagnosis'. Nevertheless, also PCa patients who suffered from organ confined tumors and had negative bone scans succumb to distant metastases after complete tumor resection. It is reasonable to assume that those tumors spread to other organs long before the overt manifestation of metastases. Our current results confirm that prostate tumors are highly heterogeneous. Even a small subpopulation of cells bearing BRCA1 losses can initiate PCa cell regional and distant dissemination indicating those patients which might be at high risk of metastasis. A preliminary study performed on a small cohort of multifocal prostate cancer (PCa) detected BRCA1 allelic imbalances (AI) among circulating tumor cells (CTCs). The present analysis was aimed to elucidate the biological and clinical role of BRCA1 losses on metastatic spread and tumor progression in prostate cancer patients. Experimental Design: To map molecular progression in PCa outgrowth we used FISH analysis of tissue microarrays (TMA), lymph node sections and CTC from peripheral blood. We found that 14% of 133 tested patients carried monoallelic BRCA1 loss in at least one tumor focus. Extended molecular analysis of chr17q revealed that this aberration was often a part of larger cytogenetic rearrangement involving chr17q21 accompanied by AI of the tumor suppressor gene PTEN and lack of the BRCA1 promoter methylation. The BRCA1 losses correlated with advanced T stage (p < 0.05), invasion to pelvic lymph nodes (LN, p < 0.05) as well as BR (p < 0.01). Their prevalence was twice as high within 62 LN metastases (LNMs) as in primary tumors (27%, p < 0.01). The analysis of 11 matched primary PCa-LNM pairs confirmed the suspected transmission of genetic abnormalities between those two sites. In 4 of 7 patients with metastatic disease, BRCA1 losses appeared in a minute fraction of cytokeratin- and vimentin-positive CTCs. Small subpopulations of PCa cells bearing BRCA1 losses might be one confounding factor initiating tumor dissemination and might provide an early indicator of shortened disease-free survival.

  3. Chagas disease

    MedlinePLUS

    Chagas disease is an illness spread by insects. It is common in South and Central America. ... Chagas disease is caused by the parasite Trypanosoma cruzi. It is spread by the bite of reduviid bugs ...

  4. Children's Understanding of the Transmission of Genetic Disorders and Contagious Illnesses

    ERIC Educational Resources Information Center

    Raman, Lakshmi; Gelman, Susan A.

    2005-01-01

    The authors conducted 4 studies suggesting that children attribute different modes of transmission to genetic disorders and contagious illnesses. Study 1 presented preschoolers through 5th graders and adults with "switched-at-birth" scenarios for various disorders. Study 2 presented preschoolers with the same disorders but used contagion links in…

  5. Male Yawning Is More Contagious than Female Yawning among Chimpanzees (Pan troglodytes)

    PubMed Central

    Massen, Jorg J. M.; Vermunt, Dorith A.; Sterck, Elisabeth H. M.

    2012-01-01

    Yawn contagion is not restricted to humans and has also been reported for several non-human animal species, including chimpanzees (Pan troglodytes). Contagious yawning may lead to synchronisation of behaviour. However, the function of contagious yawning is relatively understudied. In this study, we investigated the function of contagious yawning by focusing on two types of signal providers: close social associates and leaders. We provided a captive chimpanzee colony with videos of all individuals of their own group that were either yawning, or at rest. Consistent with other studies, we demonstrated that yawning is contagious for chimpanzees, yet we did not find any effect of relationship quality on yawn contagion. However, we show that yawn contagion is significantly higher when the video model is a yawning male than when the video model was a yawning female, and that this effect is most apparent among males. As males are dominant in chimpanzee societies, male signals may be more relevant to the rest of the group than female signals. Moreover, since chimpanzees form male-bonded societies, male signals are especially relevant for other males. Therefore, we suggest that the sex-differences of yawning contagion among chimpanzees reflect the function of yawning in the synchronisation of behaviour. PMID:22808234

  6. Catch It If You Can: How Contagious Motivation Improves Group Projects and Course Satisfaction

    ERIC Educational Resources Information Center

    Krishen, Anjala S.

    2013-01-01

    This article proposes a theory-based contagious motivation model focusing on enhancing student perceptions of group projects and ultimately course satisfaction. Moreover, drawing from both pedagogical and organizational behavior literatures, a model is presented that ties together intrinsic motivation theory with social contagion and…

  7. Contagious Flow: Antecedents and Consequences of Optimal Experience in the Classroom

    ERIC Educational Resources Information Center

    Culbertson, Satoris S.; Fullagar, Clive J.; Simmons, Mathias J.; Zhu, Mengmeng

    2015-01-01

    The current study examined undergraduate student understanding of, and interest in, course material as potential antecedents to student experiences of flow within a classroom setting. In addition, the social, informative, and contagious nature of flow were examined, as was the influence of being in flow during classroom coverage of material on…

  8. Role of the Leucine Zipper of Marek's Disease Virus Oncoprotein Meq in Pathogenesis 

    E-print Network

    Suchodolski, Paulette F.

    2010-07-14

    Marek's disease virus (MDV), the etiologic agent of Marek's disease, is a potent oncogenic herpesvirus. MDV is highly contagious and elicits a rapid onset of malignant T-cell lymphomas in chickens within several weeks after infection. The MDV genome...

  9. 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.

    PubMed

    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 . PMID:26449916

  10. Infectious Diseases in Day Care.

    ERIC Educational Resources Information Center

    Sleator, Esther K.

    Discussed in this publication are infectious illnesses for which children attending day care appear to be at special risk. Also covered are the common cold, some infectious disease problems receiving media attention, and some other annoying but not serious diseases, such as head lice, pinworms, and contagious skin conditions. Causes,…

  11. Foot-and-mouth disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals. An outbreak of FMD can have a significant economic impact because of the restrictions on international trade of susceptible animals and their products with FMD-free countries. In this chapter we discuss vario...

  12. Auditory contagious yawning in domestic dogs (Canis familiaris): first evidence for social modulation.

    PubMed

    Silva, Karine; Bessa, Joana; de Sousa, Liliana

    2012-07-01

    Dogs' capacity to 'catch' human yawns has recently attracted the attention of researchers in the field of animal cognition. Following recent studies suggesting that contagion yawning in humans, and some other primates, is empathy-related, some authors have considered the possibility that the same mechanism may underlie contagious yawning in dogs. To date, however, no positive evidence has been found, and more parsimonious hypotheses have been put forward. The present study explored the 'contagion-only' hypothesis by testing whether the mere sound of a human yawn can be sufficient to elicit yawning in dogs, in a way that is unaffected by social-emotional factors. Unexpectedly, results showed an interesting interplay between contagion and social effects. Not only were dogs found to catch human yawns, but they were also found to yawn more at familiar than unfamiliar yawns. Although not allowing for conclusive inferences about the mechanisms underlying contagious yawning in dogs, this study provides first data that renders plausible empathy-based, emotionally connected, contagious yawning in these animals. PMID:22526686

  13. Diagnosis of contagious caprine pleuropneumonia by detection and identification of Mycoplasma capricolum subsp. capripneumoniae by PCR and restriction enzyme analysis.

    PubMed Central

    Bölske, G; Mattsson, J G; Bascuñana, C R; Bergström, K; Wesonga, H; Johansson, K E

    1996-01-01

    Contagious caprine pleuropneumonia (CCPP), one of the most serious and dramatic diseases of goats, is caused by Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae). This organism is very difficult to isolate and to correctly identify. In a previous report we described a method for the rapid detection and identification of M. capripneumoniae. This method is based on a PCR system by which a segment of the 16S rRNA gene from all mycoplasmas of the M. mycoides cluster can be amplified. The PCR product is then analyzed by restriction enzyme cleavage for the identification of M. capripneumoniae DNA. This system has now been further evaluated with respect to specificity and diagnostic efficacy for the identification and direct detection of the organism in clinical material. Identification by restriction enzyme analysis of amplified DNA from mycoplasmas of the M. mycoides cluster was verified for 55 strains, among which were 15 strains of M. capripneumoniae. The PCR was applied to clinical samples from the nose, ear, pharynx, pleural fluid, and lung tissue containing M. capripneumoniae or other mycoplasmas. As expected, mycoplasmas belonging to the M. mycoides cluster could be detected by the PCR. Restriction enzyme analysis of the PCR products could then be applied for the identification of M. capripneumoniae. Clinical samples and cultures containing M. capripneumoniae were dried on filter paper, to try an easier sample transport method, and were tested by PCR. M. capripneumoniae DNA could be detected in the dried specimens, but the sensitivity of the PCR test was reduced. PMID:8815084

  14. [Meleda disease (Mal de Meleda): historical shifts in perception].

    PubMed

    Gjurasi?, Marija

    2010-01-01

    Nowadays, hereditary diseases are viewed through molecular mechanisms, and one of them, which keeps occurring rather frequently in medical publications, has been named after the Island of Mljet. The world first learned about mal de Meleda from a Dubrovnik physician Luka Stulli in 1826. He described it in a number of his island patients as a non-contagious hereditary skin disease, and named it mal de Meleda (a disease of Mljet). After Stulli, numerous scientists continued to investigate its aetiology and distinctive properties, introducing new scientific procedures to research the disease. The article keeps track of the way people and medicine perceived and treated mal de Meleda patients, starting from the early 19th century to the present day. It pays special attention to how the disease was perceived and described in medical literature through history. There are no reports in writing about the disease before the 19th century, but in oral tradition it was perceived as a punishment for the sins of sacrilege, sins of piracy, or even as leftovers of leprosy brought by the crusaders. We investigated if these legends have any support in preserved historical documents and to what extent they are related to real historical events and circumstances. Influenced by the booming research in microbiology, end 19th century physicians believed the disease was an isolated focus of leprosy. However, early 20th century physicians defined it as a hereditary skin disease with changes which distinguish it from other skin conditions. Genetic nature of the disease was later confirmed by molecular science. As for its geographical origin, the most recent medical research has shown that mal de Meleda is not restricted to the island of Mljet, and that it is spread worldwide, particularly in regions that, historically, were the trading routes of the Dubrovnik Republic. This implies that the mutation has spread through migration and persists only because it is not lethal and does not affect reproduction. PMID:21073245

  15. Evolutionary History of Contagious Bovine Pleuropneumonia Using Next Generation Sequencing of Mycoplasma mycoides Subsp. mycoides “Small Colony”

    PubMed Central

    Dupuy, Virginie; Manso-Silván, Lucía; Barbe, Valérie; Thebault, Patricia; Dordet-Frisoni, Emilie; Citti, Christine; Poumarat, François; Blanchard, Alain; Breton, Marc; Sirand-Pugnet, Pascal; Thiaucourt, François

    2012-01-01

    Mycoplasma mycoides subsp. mycoides “Small Colony” (MmmSC) is responsible for contagious bovine pleuropneumonia (CBPP) in bovidae, a notifiable disease to the World Organization for Animal Health (OIE). Although its origin is not documented, the disease was known in Europe in 1773. It reached nearly world-wide distribution in the 19th century through the cattle trade and was eradicated from most continents by stamping-out policies. During the 20th century it persisted in Africa, and it reappeared sporadically in Southern Europe. Yet, classical epidemiology studies failed to explain the re-occurrence of the disease in Europe in the 1990s. The objectives of this study were to obtain a precise phylogeny of this pathogen, reconstruct its evolutionary history, estimate the date of its emergence, and determine the origin of the most recent European outbreaks. A large-scale genomic approach based on next-generation sequencing technologies was applied to construct a robust phylogeny of this extremely monomorphic pathogen by using 20 representative strains of various geographical origins. Sixty two polymorphic genes of the MmmSC core genome were selected, representing 83601 bp in total and resulting in 139 SNPs within the 20 strains. A robust phylogeny was obtained that identified a lineage specific to European strains; African strains were scattered in various branches. Bayesian analysis allowed dating the most recent common ancestor for MmmSC around 1700. The strains circulating in Sub-Saharan Africa today, however, were shown to descend from a strain that existed around 1810. MmmSC emerged recently, about 300 years ago, and was most probably exported from Europe to other continents, including Africa, during the 19th century. Its diversity is now greater in Africa, where CBPP is enzootic, than in Europe, where outbreaks occurred sporadically until 1999 and where CBPP may now be considered eradicated unless MmmSC remains undetected. PMID:23071648

  16. Analysis of immune responses to recombinant proteins from strains of Mycoplasma mycoides subsp. mycoides, the causative agent of contagious bovine pleuropneumonia.

    PubMed

    Perez-Casal, Jose; Prysliak, Tracy; Maina, Teresa; Wang, Yejun; Townsend, Hugh; Berverov, Emil; Nkando, Isabel; Wesonga, Hezron; Liljander, Anne; Jores, Joerg; Naessens, Jan; Gerdts, Volker; Potter, Andrew

    2015-11-15

    Current contagious bovine pleuropneumonia (CBPP) vaccines are based on live-attenuated strains of Mycoplasma mycoides subsp. mycoides (Mmm). These vaccines have shortcomings in terms of efficacy, duration of immunity and in some cases show severe side effects at the inoculation site; hence the need to develop new vaccines to combat the disease. Reverse vaccinology approaches were used and identified 66 candidate Mycoplasma proteins using available Mmm genome data. These proteins were ranked by their ability to be recognized by serum from CBPP-positive cattle and thereafter used to inoculate naïve cattle. We report here the inoculation of cattle with recombinant proteins and the subsequent humoral and T-cell-mediated immune responses to these proteins and conclude that a subset of these proteins are candidate molecules for recombinant protein-based subunit vaccines for CBPP control. PMID:26384697

  17. Willingness to pay for contagious bovine pleuropneumonia vaccination in Narok South District of Kenya.

    PubMed

    Kairu-Wanyoike, Salome W; Kaitibie, Simeon; Heffernan, Claire; Taylor, Nick M; Gitau, George K; Kiara, Henry; McKeever, Declan

    2014-08-01

    Contagious bovine pleuropneumonia (CBPP) is an economically important trans-boundary cattle disease which affects food security and livelihoods. A conjoint analysis-contingent valuation was carried out on 190 households in Narok South District of Kenya to measure willingness to pay (WTP) and demand for CBPP vaccine and vaccination as well as factors affecting WTP. The mean WTP was calculated at Kenya Shillings (KSh) 212.48 (USD 3.03) for vaccination using a vaccine with the characteristics that were preferred by the farmers (preferred vaccine and vaccination) and KSh -71.45 (USD -1.02) for the currently used vaccine and vaccination. The proportion of farmers willing to pay an amount greater than zero was 66.7% and 34.4% for the preferred and current vaccine and vaccination respectively. About one third (33.3%) of farmers would need to be compensated an average amount of KSh 1162.62 (USD 13.68) per animal to allow their cattle to be vaccinated against CBPP using the preferred vaccine and vaccination. About two-thirds (65.6%) of farmers would need to be compensated an average amount of KSh 853.72 (USD 12.20) per animal to allow their cattle to be vaccinated against CBPP using the current vaccine and vaccination. The total amount of compensation would be KSh 61.39 million (USD 0.88 million) for the preferred vaccine and vaccination and KSh 90.15 million (USD 1.29 million) for the current vaccine and vaccination. Demand curves drawn from individual WTP demonstrated that only 59% and 27% of cattle owners with a WTP greater than zero were willing to pay a benchmark cost of KSh 34.60 for the preferred and current vaccine respectively. WTP was negatively influenced by the attitude about household economic situation (p=0.0078), presence of cross breeds in the herd (p<0.0001) and years since CBPP had been experienced in the herd (p=0.0375). It was positively influenced by education (p=0.0251) and the practice of treating against CBPP (p=0.0432). The benefit cost ratio (BCR) for CBPP vaccination was 2.9-6.1 depending on the vaccination programme. In conclusion, although a proportion of farmers was willing to pay, participation levels may be lower than those required to interrupt transmission of CBPP. Households with characteristics that influence WTP negatively need persuasion to participate in CBPP vaccination. It is economically worthwhile to vaccinate against CBPP. A benefit cost analysis (BCA) using aggregated WTP as benefits can be used as an alternative method to the traditional BCA which uses avoided production losses (new revenue) and costs saved as benefits. PMID:24774477

  18. Willingness to pay for contagious bovine pleuropneumonia vaccination in Narok South District of Kenya

    PubMed Central

    Kairu-Wanyoike, Salome W.; Kaitibie, Simeon; Heffernan, Claire; Taylor, Nick M.; Gitau, George K.; Kiara, Henry; McKeever, Declan

    2014-01-01

    Contagious bovine pleuropneumonia (CBPP) is an economically important trans-boundary cattle disease which affects food security and livelihoods. A conjoint analysis–contingent valuation was carried out on 190 households in Narok South District of Kenya to measure willingness to pay (WTP) and demand for CBPP vaccine and vaccination as well as factors affecting WTP. The mean WTP was calculated at Kenya Shillings (KSh) 212.48 (USD 3.03) for vaccination using a vaccine with the characteristics that were preferred by the farmers (preferred vaccine and vaccination) and KSh ?71.45 (USD ?1.02) for the currently used vaccine and vaccination. The proportion of farmers willing to pay an amount greater than zero was 66.7% and 34.4% for the preferred and current vaccine and vaccination respectively. About one third (33.3%) of farmers would need to be compensated an average amount of KSh 1162.62 (USD 13.68) per animal to allow their cattle to be vaccinated against CBPP using the preferred vaccine and vaccination. About two-thirds (65.6%) of farmers would need to be compensated an average amount of KSh 853.72 (USD 12.20) per animal to allow their cattle to be vaccinated against CBPP using the current vaccine and vaccination. The total amount of compensation would be KSh 61.39 million (USD 0.88 million) for the preferred vaccine and vaccination and KSh 90.15 million (USD 1.29 million) for the current vaccine and vaccination. Demand curves drawn from individual WTP demonstrated that only 59% and 27% of cattle owners with a WTP greater than zero were willing to pay a benchmark cost of KSh 34.60 for the preferred and current vaccine respectively. WTP was negatively influenced by the attitude about household economic situation (p = 0.0078), presence of cross breeds in the herd (p < 0.0001) and years since CBPP had been experienced in the herd (p = 0.0375). It was positively influenced by education (p = 0.0251) and the practice of treating against CBPP (p = 0.0432). The benefit cost ratio (BCR) for CBPP vaccination was 2.9–6.1 depending on the vaccination programme. In conclusion, although a proportion of farmers was willing to pay, participation levels may be lower than those required to interrupt transmission of CBPP. Households with characteristics that influence WTP negatively need persuasion to participate in CBPP vaccination. It is economically worthwhile to vaccinate against CBPP. A benefit cost analysis (BCA) using aggregated WTP as benefits can be used as an alternative method to the traditional BCA which uses avoided production losses (new revenue) and costs saved as benefits. PMID:24774477

  19. Feeder use predicts both acquisition and transmission of a contagious pathogen in a North American songbird.

    PubMed

    Adelman, James S; Moyers, Sahnzi C; Farine, Damien R; Hawley, Dana M

    2015-09-22

    Individual heterogeneity can influence the dynamics of infectious diseases in wildlife and humans alike. Thus, recent work has sought to identify behavioural characteristics that contribute disproportionately to individual variation in pathogen acquisition (super-receiving) or transmission (super-spreading). However, it remains unknown whether the same behaviours enhance both acquisition and transmission, a scenario likely to result in explosive epidemics. Here, we examined this possibility in an ecologically relevant host-pathogen system: house finches and their bacterial pathogen, Mycoplasma gallisepticum, which causes severe conjunctivitis. We examined behaviours likely to influence disease acquisition (feeder use, aggression, social network affiliations) in an observational field study, finding that the time an individual spends on bird feeders best predicted the risk of conjunctivitis. To test whether this behaviour also influences the likelihood of transmitting M. gallisepticum, we experimentally inoculated individuals based on feeding behaviour and tracked epidemics within captive flocks. As predicted, transmission was fastest when birds that spent the most time on feeders initiated the epidemic. Our results suggest that the same behaviour underlies both pathogen acquisition and transmission in this system and potentially others. Identifying individuals that exhibit such behaviours is critical for disease management. PMID:26378215

  20. Flu is a serious contagious disease. Each year in the United States, on average, more

    E-print Network

    Ishida, Yuko

    include: fever (usually high) headache extreme tiredness dry cough runny or stuffy nose muscle aches with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it. Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective

  1. Animal health: foot-and-mouth disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is one of the most contagious viral diseases that can affect cloven-hoofed livestock and wild animals. Outbreaks of FMD have caused devastating economic losses and the slaughter of millions of animals in many regions of the world affecting the food chain and global devel...

  2. Transcriptional profiling of bovine Johne's Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Johne's Disease is a chronic, contagious disease prevalent in ruminants. The animal is infected early in life by the bacteria Mycobacterium avium subsp. paratuberculosis (MAP). The characteristic symptoms of rapid weight loss and diarrhea may not appear for years after infection. We investigated t...

  3. Infectious disease modeling of social contagion in networks.

    PubMed

    Hill, Alison L; Rand, David G; Nowak, Martin A; Christakis, Nicholas A

    2010-01-01

    Many behavioral phenomena have been found to spread interpersonally through social networks, in a manner similar to infectious diseases. An important difference between social contagion and traditional infectious diseases, however, is that behavioral phenomena can be acquired by non-social mechanisms as well as through social transmission. We introduce a novel theoretical framework for studying these phenomena (the SISa model) by adapting a classic disease model to include the possibility for 'automatic' (or 'spontaneous') non-social infection. We provide an example of the use of this framework by examining the spread of obesity in the Framingham Heart Study Network. The interaction assumptions of the model are validated using longitudinal network transmission data. We find that the current rate of becoming obese is 2 per year and increases by 0.5 percentage points for each obese social contact. The rate of recovering from obesity is 4 per year, and does not depend on the number of non-obese contacts. The model predicts a long-term obesity prevalence of approximately 42, and can be used to evaluate the effect of different interventions on steady-state obesity. Model predictions quantitatively reproduce the actual historical time course for the prevalence of obesity. We find that since the 1970s, the rate of recovery from obesity has remained relatively constant, while the rates of both spontaneous infection and transmission have steadily increased over time. This suggests that the obesity epidemic may be driven by increasing rates of becoming obese, both spontaneously and transmissively, rather than by decreasing rates of losing weight. A key feature of the SISa model is its ability to characterize the relative importance of social transmission by quantitatively comparing rates of spontaneous versus contagious infection. It provides a theoretical framework for studying the interpersonal spread of any state that may also arise spontaneously, such as emotions, behaviors, health states, ideas or diseases with reservoirs. PMID:21079667

  4. RNAi-based strategy for Asian citrus psyllid (Diaphorina citri) Control: A method to reduce the spread of citrus greening disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening disease is a serious bacterial disease of citrus worldwide and is vectored by the Asian citrus pysllid (Diaphorina Citri). The only effective control strategy includes vigorous control of the psyllid, primarily through heavy reliance on pesticides. As a more sustainable and environm...

  5. Auditory Contagious Yawning in Humans: An Investigation into Affiliation and Status Effects

    PubMed Central

    Massen, Jorg J. M.; Church, Allyson M.; Gallup, Andrew C.

    2015-01-01

    While comparative research on contagious yawning has grown substantially in the past few years, both the interpersonal factors influencing this response and the sensory modalities involved in its activation in humans remain relatively unknown. Extending upon previous studies showing various in-group and status effects in non-human great apes, we performed an initial study to investigate how the political affiliation (Democrat vs. Republican) and status (high vs. low) of target stimuli influences auditory contagious yawning, as well as the urge to yawn, in humans. Self-report responses and a subset of video recordings were analyzed from 118 undergraduate students in the US following exposure to either breathing (control) or yawning (experimental) vocalizations paired with images of former US Presidents (high status) and their respective Cabinet Secretaries of Commerce (low status). The overall results validate the use of auditory stimuli to prompt yawn contagion, with greater response in the experimental than the control condition. There was also a negative effect of political status on self-reported yawning and the self-reported urge to yawn irrespective of the condition. In contrast, we found no evidence for a political affiliation bias in this response. These preliminary findings are discussed in terms of the existing comparative evidence, though we highlight limitations in the current investigation and we provide suggestions for future research in this area. PMID:26617557

  6. Interactions of foot-and-mouth disease virus with cells in organised lymphoid tissue influence innate and adaptive immune responses 

    E-print Network

    Juleff, Nicholas Dylan

    2009-01-01

    Foot-and-mouth disease virus (FMDV) is one of the most contagious viruses of animals and is recognised as the most important constraint to international trade in animals and animal products. Two fundamental problems remain to be understood before...

  7. Low major histocompatibility complex diversity in the Tasmanian devil predates European settlement and may explain susceptibility to disease epidemics.

    PubMed

    Morris, Katrina; Austin, Jeremy J; Belov, Katherine

    2013-02-23

    The Tasmanian devil (Sarcophilus harrisii) is at risk of extinction owing to the emergence of a contagious cancer known as devil facial tumour disease (DFTD). The emergence and spread of DFTD has been linked to low genetic diversity in the major histocompatibility complex (MHC). We examined MHC diversity in historical and ancient devils to determine whether loss of diversity is recent or predates European settlement in Australia. Our results reveal no additional diversity in historical Tasmanian samples. Mainland devils had common modern variants plus six new variants that are highly similar to existing alleles. We conclude that low MHC diversity has been a feature of devil populations since at least the Mid-Holocene and could explain their tumultuous history of population crashes. PMID:23221872

  8. Low major histocompatibility complex diversity in the Tasmanian devil predates European settlement and may explain susceptibility to disease epidemics

    PubMed Central

    Morris, Katrina; Austin, Jeremy J.; Belov, Katherine

    2013-01-01

    The Tasmanian devil (Sarcophilus harrisii) is at risk of extinction owing to the emergence of a contagious cancer known as devil facial tumour disease (DFTD). The emergence and spread of DFTD has been linked to low genetic diversity in the major histocompatibility complex (MHC). We examined MHC diversity in historical and ancient devils to determine whether loss of diversity is recent or predates European settlement in Australia. Our results reveal no additional diversity in historical Tasmanian samples. Mainland devils had common modern variants plus six new variants that are highly similar to existing alleles. We conclude that low MHC diversity has been a feature of devil populations since at least the Mid-Holocene and could explain their tumultuous history of population crashes. PMID:23221872

  9. Characteristics of cyprinid herpesvirus 3 in different phases of infection: implications for disease transmission and control.

    PubMed

    Sunarto, Agus; McColl, Kenneth A; Crane, Mark St J; Schat, Karel A; Slobedman, Barry; Barnes, Andrew C; Walker, Peter J

    2014-08-01

    Koi herpesvirus disease (KHVD) is an emerging and highly contagious viral disease of koi and common carp (Cyprinus carpio), causing mass mortalities and huge economic losses to the carp aquaculture industry. The disease has spread rapidly to 28 countries worldwide. However, mechanisms of koi herpesvirus (species Cyprinid herpesvirus 3; CyHV-3) transmission remain unclear. A potential experimental model of CyHV-3 infection in carp was used to characterise CyHV-3 in different phases of infection and to demonstrate that CyHV-3 persists in survivor fish and has the capacity to reactivate and transmit the disease to healthy fish. During acute infection, which occurred when fish were maintained at 22°C, viral genes were abundantly expressed and infectious virus was produced in association with tissue damage, clinical disease and mortality. In fish maintained at a lower temperature (11°C), viral DNA was present but viral gene expression was absent or greatly restricted, infectious virus was not recovered and there was no evidence of disease. Productive replication was re-initiated following an increase in water temperature to 22°C, resulting in 45% mortality. Shedding of reactivated virus killed 75% of cohabitating naïve fish, suggesting a potential risk for disease transmission. PMID:24704574

  10. Contagious Fire? An Empirical Assessment of the Problem of Multi-Shooter, Multi-Shot Deadly Force Incidents in Police Work

    ERIC Educational Resources Information Center

    White, Michael D.; Klinger, David

    2012-01-01

    Recent police shootings in which multiple officers fired numerous rounds at suspects have led some observers to assert that such situations involve "contagious fire," where an initial officer's shots launch a cascade of gunfire from other officers present. Although there is anecdotal recognition of the contagious fire phenomenon among police and…

  11. Novel antiviral therapeutics to control foot-and-mouth disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) causes a highly contagious disease of cloven-hoofed animals. Vaccines require approximately 7 days to induce protection, thus prior to this time vaccinated animals are still susceptible to the disease. Our group has previously shown that swine inoculated with 1x10...

  12. Immunological Basis for Resistance and Susceptibility to Marek's Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is a contagious lymphoproliferative disease of domestic chickens caused by a highly cell-associated alpha-herpesvirus, Marek’s disease virus (MDV). MDV replicates in chicken lymphocytes and establishes a latent infection within CD4+ T cells. Mechanisms of viral pathogenesis, r...

  13. Foot-and-mouth disease: global status and Indian perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is a highly contagious and transboundary viral disease of domesticated and wild cloven-hoofed animals. Wide prevalence of the disease in Asia and Africa associated with huge economic loss to the livestock farming and industry has increased the concern worldwide. The di...

  14. Name: ____________________________________ Invasive Species Spread

    E-print Network

    Lega, Joceline

    how far the Cane Toad, Bufo marinus, has spread. It was originally introduced in 1930s to Gordonvale in slope-intercept form. 5) How far do you think the cane toads will go by the year 2025? 6) Using the data? #12;ANSWER KEY Below are pictures that indicate how far the Cane Toad, Bufo marinus, has spread

  15. Targeting juvenile hormone metabolic genes in the Asian citrus psyllid (Diaphorina citri Kuwayama) as a strategy to reduce the spread of citrus greening disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama, the Asian citrus psyllid (ACP), is a devastating citrus pest due to its transmission of a phloem-limited bacterial pathogen, Candidatus Liberibacter asiaticus, that causes citrus greening. Psyllid control is a major part of effective greening disease management, and our r...

  16. Contagious error sources would need time travel to prevent quantum computation

    E-print Network

    Gil Kalai; Greg Kuperberg

    2015-05-07

    We consider an error model for quantum computing that consists of "contagious quantum germs" that can infect every output qubit when at least one input qubit is infected. Once a germ actively causes error, it continues to cause error indefinitely for every qubit it infects, with arbitrary quantum entanglement and correlation. Although this error model looks much worse than quasi-independent error, we show that it reduces to quasi-independent error with the technique of quantum teleportation. The construction, which was previously described by Knill, is that every quantum circuit can be converted to a mixed circuit with bounded quantum depth. We also consider the restriction of bounded quantum depth from the point of view of quantum complexity classes.

  17. Contagious error sources would need time travel to prevent quantum computation

    NASA Astrophysics Data System (ADS)

    Kalai, Gil; Kuperberg, Greg

    2015-08-01

    We consider an error model for quantum computing that consists of "contagious quantum germs" that can infect every output qubit when at least one input qubit is infected. Once a germ actively causes error, it continues to cause error indefinitely for every qubit it infects, with arbitrary quantum entanglement and correlation. Although this error model looks much worse than quasi-independent error, we show that it reduces to quasi-independent error with the technique of quantum teleportation. The construction, which was previously described by Knill, is that every quantum circuit can be converted to a mixed circuit with bounded quantum depth. We also consider the restriction of bounded quantum depth from the point of view of quantum complexity classes.

  18. Timing of activation of CD4+ memory cells as a possible marker to establish the efficacy of vaccines against contagious agalactia in sheep.

    PubMed

    Agnone, Annalisa; La Manna, Marco P; Loria, Guido R; Puleio, Roberto; Villari, Sara; Nicholas, Robin A J; Guggino, Giuliana; Sireci, Guido

    2013-04-15

    Mycoplasma agalactiae is a major pathogen of sheep and goats in many areas of the world and particularly in Mediterranean countries. It causes contagious agalactia, an infectious disease primarily affecting mammary glands. Many vaccines against the pathogen are currently under development. The aim of the study was to investigate the involvement of T cell-mediated immunity during vaccination and challenge experiments against Mycoplasma agalactiae. A comparison of the antigen-specific expansion of interferon gamma positive T cell memory and naïve subsets was performed between vaccinated and non-vaccinated sheep to identify cellular subsets whose activation was different between protected and non-protected sheep. Data reported in this manuscript demonstrated that two out of the three vaccines used in this study protected sheep from the disease. In the protected groups CD4(+) memory interferon-?(+) T cells underwent an early expansion (p<0.05 when compared to unprotected groups), whilst memory CD8(+) Interferon-?(+) T cells increased in non-protected animals 7 days after infection (p<0.05). ??(+) Interferon-?(+) T cells reached peaks of expansion in infected and in two vaccinated groups thus indicating that these cells are not preferentially involved in protection or pathogenesis (p<0.05). Hereby we propose that the early activation of CD4(+) memory Interferon-?(+) T cells could be considered as a marker of protection from the disease as well as a tool to establish vaccine efficacy. PMID:23333193

  19. Mutant copper-zinc superoxide dismutase (SOD1) induces protein secretion pathway alterations and exosome release in astrocytes: implications for disease spreading and motor neuron pathology in amyotrophic lateral sclerosis.

    PubMed

    Basso, Manuela; Pozzi, Silvia; Tortarolo, Massimo; Fiordaliso, Fabio; Bisighini, Cinzia; Pasetto, Laura; Spaltro, Gabriella; Lidonnici, Dario; Gensano, Francesco; Battaglia, Elisa; Bendotti, Caterina; Bonetto, Valentina

    2013-05-31

    Amyotrophic lateral sclerosis is the most common motor neuron disease and is still incurable. The mechanisms leading to the selective motor neuron vulnerability are still not known. The interplay between motor neurons and astrocytes is crucial in the outcome of the disease. We show that mutant copper-zinc superoxide dismutase (SOD1) overexpression in primary astrocyte cultures is associated with decreased levels of proteins involved in secretory pathways. This is linked to a general reduction of total secreted proteins, except for specific enrichment in a number of proteins in the media, such as mutant SOD1 and valosin-containing protein (VCP)/p97. Because there was also an increase in exosome release, we can deduce that astrocytes expressing mutant SOD1 activate unconventional secretory pathways, possibly as a protective mechanism. This may help limit the formation of intracellular aggregates and overcome mutant SOD1 toxicity. We also found that astrocyte-derived exosomes efficiently transfer mutant SOD1 to spinal neurons and induce selective motor neuron death. We conclude that the expression of mutant SOD1 has a substantial impact on astrocyte protein secretion pathways, contributing to motor neuron pathology and disease spread. PMID:23592792

  20. Legionnaires' Disease

    MedlinePLUS

    Legionnaires' disease is a type of pneumonia caused by bacteria. You usually get it by breathing in mist from ... spread from person to person. Symptoms of Legionnaires' disease include high fever, chills, a cough, and sometimes ...

  1. Chagas Disease

    MedlinePLUS

    Chagas disease is caused by a parasite. It is common in Latin America but not in the United States. ... nose, the bite wound or a cut. The disease can also spread through contaminated food, a blood ...

  2. Fifth disease

    MedlinePLUS

    Parvovirus B19; Erythema infectiosum; Slapped cheek rash ... Fifth disease is caused by human parvovirus B19. It often affects preschoolers or school-age children during the spring. The disease spreads through the fluids in the nose and ...

  3. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Appearance of disease among ruminants... disease among ruminants in quarantine. If any contagious disease appears among ruminants during the... the Administrator may direct, depending upon the nature of the disease. Canada 8 8 Importations...

  4. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Appearance of disease among ruminants... disease among ruminants in quarantine. If any contagious disease appears among ruminants during the... the Administrator may direct, depending upon the nature of the disease. Canada 8 8 Importations...

  5. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Appearance of disease among ruminants... disease among ruminants in quarantine. If any contagious disease appears among ruminants during the... the Administrator may direct, depending upon the nature of the disease. Canada 8 8 Importations...

  6. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Appearance of disease among ruminants... disease among ruminants in quarantine. If any contagious disease appears among ruminants during the... the Administrator may direct, depending upon the nature of the disease. Canada 8 8 Importations...

  7. 9 CFR 93.416 - Appearance of disease among ruminants in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Appearance of disease among ruminants... disease among ruminants in quarantine. If any contagious disease appears among ruminants during the... the Administrator may direct, depending upon the nature of the disease. Canada 8 8 Importations...

  8. Technique for controlling spread of limnotic oncomelania

    NASA Astrophysics Data System (ADS)

    Li, Damei; Wang, Xiangsan; Lai, Yonggen

    2003-09-01

    Schistosomiasis is a parasitic disease mostly found in areas along the Changjiang River of China. The disease is spread solely through an intermediary named oncomelania, so its spread of schistosomiasis can be controlled by properly designing water intakes which prevent oncomelania from entering farming land or residential areas. This paper reports a successful design process and a new oncomelania-free intake device. The design of the new intake is based on a sound research program in which extensive experimental studies were carried out to gain knowledge of oncomelania eco-hydraulic behavior and detailed flow field information through CFD simulation.

  9. Spreading Depression, Spreading Depolarizations, and the Cerebral Vasculature.

    PubMed

    Ayata, Cenk; Lauritzen, Martin

    2015-07-01

    Spreading depression (SD) is a transient wave of near-complete neuronal and glial depolarization associated with massive transmembrane ionic and water shifts. It is evolutionarily conserved in the central nervous systems of a wide variety of species from locust to human. The depolarization spreads slowly at a rate of only millimeters per minute by way of grey matter contiguity, irrespective of functional or vascular divisions, and lasts up to a minute in otherwise normal tissue. As such, SD is a radically different breed of electrophysiological activity compared with everyday neural activity, such as action potentials and synaptic transmission. Seventy years after its discovery by Leão, the mechanisms of SD and its profound metabolic and hemodynamic effects are still debated. What we did learn of consequence, however, is that SD plays a central role in the pathophysiology of a number of diseases including migraine, ischemic stroke, intracranial hemorrhage, and traumatic brain injury. An intriguing overlap among them is that they are all neurovascular disorders. Therefore, the interplay between neurons and vascular elements is critical for our understanding of the impact of this homeostatic breakdown in patients. The challenges of translating experimental data into human pathophysiology notwithstanding, this review provides a detailed account of bidirectional interactions between brain parenchyma and the cerebral vasculature during SD and puts this in the context of neurovascular diseases. PMID:26133935

  10. Variola minor in Bragança Paulista County, 1956: lack of evidence indicating the influence of contaminated classrooms on spread of the disease*

    PubMed Central

    Klauber, Melville R.; Angulo, Juan J.

    1974-01-01

    Space-time interaction analysis was applied to data from 101 elementary school children who contracted variola minor during an epidemic in Bragança Paulista County, Brazil. One school had two and the other three shifts of students occupying the same classrooms each day. There was no evidence found for excessive numbers of cases to occur among unvaccinated students occupying the same desks or seated near the desks occupied by cases occurring during another shift. Only three cases occurred among the 31 unvaccinated students occupying desks of students with variola from other shifts. Only one of these three subsequent cases occurred at a time interval suggestive of transmission. For the three models tested there was no evidence of space-time interaction between time of onset of the disease and location of desk for pairs of students from different shifts. PMID:4522722

  11. Qualitative assessment of the commodity risk for spread of foot-and-mouth disease associated with international trade in deboned beef.

    PubMed

    Paton, D J; Sinclair, M; Rodríguez, R

    2010-06-01

    The risk of importing foot-and-mouth disease virus (FMDV) restricts trade in livestock and their products from parts of the world where the virus is present. This reduces trade opportunities and investment in the livestock sector of many developing countries and constrains global food supply. This review focuses on the risks associated with trade in deboned beef (DB) from foot-and-mouth disease (FMD)-infected cattle, countries or zones. A definition of DB is provided along with a description of the procedures for its preparation within beef slaughtering operations. Evidence is reviewed for circumstances under which DB can be contaminated with FMDV, and a commodity risk factor approach is used to consider the mitigating efficacy of slaughterhouse procedures. A combination of pre-slaughter and slaughterhouse measures has enabled DB to be safely imported into FMD-free countries from countries that were not nationally or zonally FMD-free. Nevertheless, current evidence does not provide absolute assurance that abattoir procedures for producing DB can result, by themselves, in a commodity with a negligible risk of transmitting FMDV without complementary measures to reduce the likelihood of slaughtering infected cattle. The main areas of uncertainty are the amounts of residual FMDV-harbouring tissues within DB, and our understanding of what constitutes a safe level of contamination. More detailed guidance should be developed to specify the mitigating measures needed in support of the export of DB from regions that are not officially FMD-free. This will help to avoid differences in interpretation of what is needed that give rise to obstacles to trade. PMID:20569417

  12. Tan F. Wong: Spread Spectrum & CDMA 2. Intro. Spread Spectrum Introduction to Spread Spectrum

    E-print Network

    Wong, Tan F.

    Tan F. Wong: Spread Spectrum & CDMA 2. Intro. Spread Spectrum Chapter 2 Introduction to Spread Spectrum Communications As discussed in Chapter 0, a spread spectrum modulation produces a transmitted spectrum much wider than the minimum bandwidth required. There are many ways to generate spread spectrum

  13. Spreading of Cholera through Surface Water

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    Cholera epidemics are still a major public health concern to date in many areas of the world. In order to understand and forecast cholera outbreaks, one of the most important factors is the role played by the environmental matrix in which the disease spreads. We study how river networks, acting as environmental corridors for pathogens, affect the spreading of cholera epidemics. The environmental matrix in which the disease spreads is constituted by different human communities and their hydrologic interconnections. Each community is characterized by its spatial position, population size, water resources availability and hygiene conditions. By implementing a spatially explicit cholera model we seek the effects on epidemic dynamics of: i) the topology and metrics of the pathogens pathways that connect different communities; ii) the spatial distribution of the population size; and iii) the spatial distributions and quality of surface water resources and public health conditions, and how they vary with population size. The model has been applied to study the space-time evolution of a well documented cholera epidemic occurred in the KwaZulu-Natal province of South Africa. The epidemic lasted for two years and involved about 140,000 confirmed cholera cases. The model does well in reproducing the distribution of the cholera cases during the two outbreaks as well as their spatial spreading. We further extend the model by deriving the speed of propagation of traveling fronts in the case of uniformly distributed systems for different topologies: one and two dimensional lattices and river networks. The derivation of the spreading celerity proves instrumental in establishing the overall conditions for the relevance of spatially explicit models. The conditions are sought by comparison between spreading and disease timescales. Consider a cholera epidemic that starts from a point and spreads throughout a finite size system, it is possible to identify two different timescales: i) the spreading timescale, that is the time needed for the disease to spread and involve all the communities in the system; and ii) the epidemic timescale, defined by the duration of the epidemic in a single community. Our results suggest that in many cases of real-life epidemiological interest, timescales of disease dynamics may trigger outbreaks that significantly depart from the predictions of classical space-implicit compartmental models.

  14. Newcastle disease virus detection and differentiation from avian influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newcastle disease (ND) is a contagious and often fatal disease that affects over 250 bird species worldwide, and is caused by infection with virulent strains of avian paramyxovirus-1 (APMV-1) of the family Paramyxoviridae, genus Avulavirus. Infections of poultry with virulent strains of APMV-1 (New...

  15. Management and Conservation Note Alternative Feeding Strategies and Potential Disease

    E-print Network

    of cervids, is the only transmissible spongiform encephalopathy known to cause contagious disease in wild to transmission of several wildlife diseases, including bovine tuberculosis (TB) and brucellosis in cervids transmission of bovine TB in Michigan's (USA) wild deer population (Schmitt et al. 1997, Garner 2001, Miller et

  16. Familiarity-connected or stress-based contagious yawning in domestic dogs (Canis familiaris)? Some additional data.

    PubMed

    Silva, Karine; Bessa, Joana; de Sousa, Liliana

    2013-11-01

    The present short note aimed at further exploring data from a recent study showing socially modulated auditory contagious yawning in domestic dogs (Canis familiaris). Two independent observers further extended the analysis of all video recordings made in the previous study and coded both the number of yawns performed by the dogs and the frequencies or durations of stress-related behaviors exhibited throughout the presentation of familiar and unfamiliar yawns. By showing no significant difference between conditions in the frequencies or durations of the coded behaviors, nor any association between the number of yawns and the frequencies or durations of stress-related behaviors, results raised doubt on the stress-induced yawn hypothesis, thus supporting social modulation. The exact mechanism underlying contagious yawning, however, needs further research. PMID:23982621

  17. Spatiotemporal Phylogenetic Analysis and Molecular Characterisation of Infectious Bursal Disease Viruses Based on the VP2 Hyper-Variable Region

    PubMed Central

    Dolz, Roser; Valle, Rosa; Perera, Carmen L.; Bertran, Kateri; Frías, Maria T.; Majó, Natàlia; Ganges, Llilianne; Pérez, Lester J.

    2013-01-01

    Background Infectious bursal disease is a highly contagious and acute viral disease caused by the infectious bursal disease virus (IBDV); it affects all major poultry producing areas of the world. The current study was designed to rigorously measure the global phylogeographic dynamics of IBDV strains to gain insight into viral population expansion as well as the emergence, spread and pattern of the geographical structure of very virulent IBDV (vvIBDV) strains. Methodology/Principal Findings Sequences of the hyper-variable region of the VP2 (HVR-VP2) gene from IBDV strains isolated from diverse geographic locations were obtained from the GenBank database; Cuban sequences were obtained in the current work. All sequences were analysed by Bayesian phylogeographic analysis, implemented in the Bayesian Evolutionary Analysis Sampling Trees (BEAST), Bayesian Tip-association Significance testing (BaTS) and Spatial Phylogenetic Reconstruction of Evolutionary Dynamics (SPREAD) software packages. Selection pressure on the HVR-VP2 was also assessed. The phylogeographic association-trait analysis showed that viruses sampled from individual countries tend to cluster together, suggesting a geographic pattern for IBDV strains. Spatial analysis from this study revealed that strains carrying sequences that were linked to increased virulence of IBDV appeared in Iran in 1981 and spread to Western Europe (Belgium) in 1987, Africa (Egypt) around 1990, East Asia (China and Japan) in 1993, the Caribbean Region (Cuba) by 1995 and South America (Brazil) around 2000. Selection pressure analysis showed that several codons in the HVR-VP2 region were under purifying selection. Conclusions/Significance To our knowledge, this work is the first study applying the Bayesian phylogeographic reconstruction approach to analyse the emergence and spread of vvIBDV strains worldwide. PMID:23805195

  18. Molecular Analysis of Spring Viraemia of Carp Virus in China: A Fatal Aquatic Viral Disease that Might Spread in East Asian

    PubMed Central

    Jiang, Yi Nan; Zhang, Ting; Xia, Chun

    2009-01-01

    Spring viraemia of carp (SVC) is a fatal viral disease for cyprinid fish, which is caused by spring viraemia of carp virus (SVCV). To date, no SVC outbreak has been reported in China. Between 1998 and 2002, outbreaks of SVC were reported in ornamental and wild fish in Europe and America, imported from multiple sources including China. Based on phylogenetic analysis, the viral strain isolated from America was shown to be originated from Asia. These outbreaks not only resulted in huge economic losses, but also raise an interesting question as to whether SVCV really exists in China and if so, is it responsible for SVC outbreaks? From 2002 to 2006, we screened 6700 samples from ornamental fish farms using the cell culture method of the Office International des Epizooties (OIE), and further verified the presence of SVCV by ELISA and real-time quantitative RT-PCR. Two infected samples were found and the complete genome of SVCV was sequenced from one of the isolates, termed SVCV-C1. Several unique hallmarks of SVCV-C1 were identified, including six amino acid (KSLANA) insertion in the viral RNA-dependent RNA polymerase (L) protein and ten nucleotide insertion in the region between glycoprotein (G) and L genes in European SVCV strains. Phylogenetic tree analysis of the full-length G protein of selected SVCV isolates from the United Kingdom and United States revealed that G proteins could be classified into Ia and Id sub genogroups. The Ia sub genogroup can be further divided into newly defined sub genogroups Ia-A and Ia-B. The isolates derived from the United States and China including the SVCV-C1 belongs to in the Ia-A sub genogroup. The SVCV-C1 G protein shares more than 99% homology with the G proteins of the SVCV strains from England and the United States, making it difficult to compare their pathogenicity. Comparison of the predicted three-dimensional structure based on the published G protein sequences from five SVCV strains revealed that the main differences were in the loops of the pleckstrin homology domains. Since SVCV is highly pathogenic, we speculate that SVC may therefore pose a serious threat to farmed cyprinid fish in China. PMID:19623265

  19. Topography driven spreading.

    PubMed

    McHale, G; Shirtcliffe, N J; Aqil, S; Perry, C C; Newton, M I

    2004-07-16

    Roughening a hydrophobic surface enhances its nonwetting properties into superhydrophobicity. For liquids other than water, roughness can induce a complete rollup of a droplet. However, topographic effects can also enhance partial wetting by a given liquid into complete wetting to create superwetting. In this work, a model system of spreading droplets of a nonvolatile liquid on surfaces having lithographically produced pillars is used to show that superwetting also modifies the dynamics of spreading. The edge speed-dynamic contact angle relation is shown to obey a simple power law, and such power laws are shown to apply to naturally occurring surfaces. PMID:15323838

  20. Kinetics of Cell Spreading

    NASA Astrophysics Data System (ADS)

    Chamaraux, F.; Fache, S.; Bruckert, F.; Fourcade, B.

    2005-04-01

    Cell spreading is a fundamental event where the contact area with a solid substrate increases because of actin polymerization. We propose in this Letter a physical model to study the growth of the contact area with time. This analysis is compared with experimental data using the ameoba Dictyostelium discoideum. Our model couples the stress, which builds up at the margin of the contact area when the cell spreads, to the biochemical processes of actin polymerization. This leads to a scaling analysis of experimental data with a characteristic time whose order of magnitude compares well with our experimental results.

  1. Emergence of blind areas in information spreading.

    PubMed

    Zhang, Zi-Ke; Zhang, Chu-Xu; Han, Xiao-Pu; Liu, Chuang

    2014-01-01

    Recently, contagion-based (disease, information, etc.) spreading on social networks has been extensively studied. In this paper, other than traditional full interaction, we propose a partial interaction based spreading model, considering that the informed individuals would transmit information to only a certain fraction of their neighbors due to the transmission ability in real-world social networks. Simulation results on three representative networks (BA, ER, WS) indicate that the spreading efficiency is highly correlated with the network heterogeneity. In addition, a special phenomenon, namely Information Blind Areas where the network is separated by several information-unreachable clusters, will emerge from the spreading process. Furthermore, we also find that the size distribution of such information blind areas obeys power-law-like distribution, which has very similar exponent with that of site percolation. Detailed analyses show that the critical value is decreasing along with the network heterogeneity for the spreading process, which is complete the contrary to that of random selection. Moreover, the critical value in the latter process is also larger than that of the former for the same network. Those findings might shed some lights in in-depth understanding the effect of network properties on information spreading. PMID:24763456

  2. Transgenic banana expressing Pflp gene confers enhanced resistance to Xanthomonas wilt disease.

    PubMed

    Namukwaya, B; Tripathi, L; Tripathi, J N; Arinaitwe, G; Mukasa, S B; Tushemereirwe, W K

    2012-08-01

    Banana Xanthomonas wilt (BXW), caused by Xanthomonas campestris pv. musacearum, is one of the most important diseases of banana (Musa sp.) and currently considered as the biggest threat to banana production in Great Lakes region of East and Central Africa. The pathogen is highly contagious and its spread has endangered the livelihood of millions of farmers who rely on banana for food and income. The development of disease resistant banana cultivars remains a high priority since farmers are reluctant to employ labor-intensive disease control measures and there is no host plant resistance among banana cultivars. In this study, we demonstrate that BXW can be efficiently controlled using transgenic technology. Transgenic bananas expressing the plant ferredoxin-like protein (Pflp) gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of banana. These transgenic lines were characterized by molecular analysis. After challenge with X. campestris pv. musacearum transgenic lines showed high resistance. About 67% of transgenic lines evaluated were completely resistant to BXW. These transgenic lines did not show any disease symptoms after artificial inoculation of in vitro plants under laboratory conditions as well as potted plants in the screen-house, whereas non-transgenic control plants showed severe symptoms resulting in complete wilting. This study confirms that expression of the Pflp gene in banana results in enhanced resistance to BXW. This transgenic technology can provide a timely solution to the BXW pandemic. PMID:22101927

  3. Early adaptive immune responses in the respiratory tract of foot and mouth disease-infected cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot and mouth disease (FMD) is a highly contagious viral disease which affects both domestic and wildlife biungulate species. This acute disease, caused by the FMD virus (FMDV), usually includes an active replication phase in the respiratory tract up to 72 h post-infection followed by hematogenous ...

  4. Newcastle Disease: Progress and gaps in the development of vaccines and diagnostic tools

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newcastle disease (ND) is a contagious disease of birds that can have severe economic consequences for any poultry producer, including a serious impact on the international trade of poultry and eggs. Newcastle disease virus (NDV) isolates are also called avian paramyxovirus serotype-1 isolates, but ...

  5. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or...

  6. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Appearance of disease among horses in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the quarantine period...

  7. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Appearance of disease among horses in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the quarantine period...

  8. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases...

  9. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Appearance of disease among swine in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the quarantine period...

  10. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Control of livestock disease and introduction of... NAVAJO GRAZING REGULATIONS § 167.15 Control of livestock disease and introduction of livestock. (a) The... contagious or infectious disease in the economic interest of the Navajo stock owners. Upon the...

  11. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Appearance of disease among poultry in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the quarantine...

  12. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Appearance of disease among swine in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the quarantine period...

  13. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Control of livestock disease and introduction of... NAVAJO GRAZING REGULATIONS § 167.15 Control of livestock disease and introduction of livestock. (a) The... contagious or infectious disease in the economic interest of the Navajo stock owners. Upon the...

  14. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Appearance of disease among horses in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the quarantine period...

  15. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases...

  16. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases...

  17. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or...

  18. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Appearance of disease among swine in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the quarantine period...

  19. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Appearance of disease among poultry in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the quarantine...

  20. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases...

  1. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Control of livestock disease and introduction of livestock... NAVAJO GRAZING REGULATIONS § 167.15 Control of livestock disease and introduction of livestock. (a) The... contagious or infectious disease in the economic interest of the Navajo stock owners. Upon the...

  2. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Appearance of disease among swine in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the quarantine period...

  3. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or...

  4. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Appearance of disease among poultry in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the quarantine...

  5. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases...

  6. 9 CFR 93.515 - Appearance of disease among swine in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Appearance of disease among swine in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Swine § 93.515 Appearance of disease among swine in quarantine. If any contagious disease appears among swine during the quarantine period...

  7. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Control of livestock disease and introduction of... NAVAJO GRAZING REGULATIONS § 167.15 Control of livestock disease and introduction of livestock. (a) The... contagious or infectious disease in the economic interest of the Navajo stock owners. Upon the...

  8. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or...

  9. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Appearance of disease among horses in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the quarantine period...

  10. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or...

  11. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Appearance of disease among poultry in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the quarantine...

  12. 25 CFR 167.15 - Control of livestock disease and introduction of livestock.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Control of livestock disease and introduction of... NAVAJO GRAZING REGULATIONS § 167.15 Control of livestock disease and introduction of livestock. (a) The... contagious or infectious disease in the economic interest of the Navajo stock owners. Upon the...

  13. 9 CFR 93.213 - Appearance of disease among poultry in quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Appearance of disease among poultry in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Poultry § 93.213 Appearance of disease among poultry in quarantine. If any contagious disease appears among poultry during the quarantine...

  14. 9 CFR 93.313 - Appearance of disease among horses in quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Appearance of disease among horses in...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious disease appears among horses during the quarantine period...

  15. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Control of livestock disease and parasites. 700.723 Section...Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock...infected with contagious or infectious disease or parasites or have been exposed...

  16. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Control of livestock disease and parasites. 700.723 Section...Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock...infected with contagious or infectious disease or parasites or have been exposed...

  17. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Control of livestock diseases and parasites. 168.15 Section...AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock...infected with contagious or infectious diseases or parasites or have been exposed...

  18. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Control of livestock diseases and parasites. 168.15 Section...AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock...infected with contagious or infectious diseases or parasites or have been exposed...

  19. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Control of livestock diseases and parasites. 168.15 Section...AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock...infected with contagious or infectious diseases or parasites or have been exposed...

  20. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Control of livestock disease and parasites. 700.723 Section...Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock...infected with contagious or infectious disease or parasites or have been exposed...

  1. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Control of livestock diseases and parasites. 168.15 Section...AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock...infected with contagious or infectious diseases or parasites or have been exposed...

  2. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Control of livestock disease and parasites. 700.723 Section...Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock...infected with contagious or infectious disease or parasites or have been exposed...

  3. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Control of livestock disease and parasites. 700.723 Section...Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock...infected with contagious or infectious disease or parasites or have been exposed...

  4. 25 CFR 168.15 - Control of livestock diseases and parasites.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2011-04-01 true Control of livestock diseases and parasites. 168.15 Section...AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock...infected with contagious or infectious diseases or parasites or have been exposed...

  5. Response Strategies in Deterministic Models of Spread: Vaccination and Firefighting

    E-print Network

    Hartke, Stephen

    38 Chapter 3 Response Strategies in Deterministic Models of Spread: Vaccination and Firefighting 3 are occurring. This is particularly relevant in disease spread processes, where vaccinations and quarantines then on. The response allowed is only a limited number of vaccinations of non­infected vertices

  6. Response Strategies in Deterministic Models of Spread: Vaccination and Firefighting

    E-print Network

    Hartke, Stephen

    38 Chapter 3 Response Strategies in Deterministic Models of Spread: Vaccination and Firefighting 3 are occurring. This is particularly relevant in disease spread processes, where vaccinations and quarantines. The response allowed is only a limited number of vaccinations of non-infected vertices. Specifically, let G

  7. The role of transnational mobility in the local spread of mosquito-borne disease: Measuring the determinants of spatial-temporal lags of imported dengue cases initiating indigenous epidemics in Taiwan

    NASA Astrophysics Data System (ADS)

    Wen, Tzai-Hung

    2014-05-01

    Dengue fever is one of the world's most widely spread mosquito-borne diseases. International travelers who acquire dengue infection are important routes for virus transmission from one country to another one. Previous studies have shown that imported dengue cases are able to initiate indigenous epidemics when appropriate weather conditions are present. However, the spatial-temporal associations between imported cases and indigenous epidemics in areas with different social-economic conditions are still unclear. This study investigated determinants of spatial-temporal lags of imported dengue cases who initiated indigenous epidemics from 2003 to 2012 in Taiwan. The quantile regression is used to explore the associations between spatial-temporal lags of imported cases and social-economic indicators with geographic heterogeneity. Our results indicated that imported cases in April and May have statistically significant contribution to initiate indigenous epidemics. Areas with high population density and low average income have significant risk of being imported virus from other areas. However, the areas with imported cases are not significant transmission risk. The results imply that imported cases reported in early summer may be an early-warning indicator of indigenous epidemics. Local demographic and economic conditions, rather than imported cases, may determine the areas with the risk of indigenous epidemics.

  8. Alone in the Crowd: The Structure and Spread of Loneliness in a Large Social Network

    PubMed Central

    Cacioppo, John T.; Fowler, James H.; Christakis, Nicholas A.

    2009-01-01

    The discrepancy between an individual’s loneliness and the number of connections in a social network is well documented, yet little is known about the placement of loneliness within, or the spread of loneliness through, social networks. We use network linkage data from the population-based Framingham Heart Study to trace the topography of loneliness in people’s social networks and the path through which loneliness spreads through these networks. Results indicated that loneliness occurs in clusters, extends up to three degrees of separation, is disproportionately represented at the periphery of social networks, and spreads through a contagious process. The spread of loneliness was found to be stronger than the spread of perceived social connections, stronger for friends than family members, and stronger for women than for men. The results advance our understanding of the broad social forces that drive loneliness and suggest that efforts to reduce loneliness in our society may benefit by aggressively targeting the people in the periphery to help repair their social networks and to create a protective barrier against loneliness that can keep the whole network from unraveling. PMID:19968414

  9. Foot-and-mouth disease: susceptibility of domestic poultry and free-living birds to infection and to disease--a review of the historical and current literature concerning the role of birds in spread of foot-and-mouth disease viruses.

    PubMed

    Kaleta, E F

    2002-09-01

    Ruminants and pigs are the dominant natural hosts of food-and-mouth disease (FMD) viruses. Approximately 70 additional mammalian species are found to be susceptible under natural or experimental conditions. Reptilia, amphibia, and fish are probably naturally resistant to infection. According to the reviewed literature, domestic birds (chickens, turkeys, guinea fowl, ducks and geese) have been experimentally infected with some strains of FMD viruses and may develop lesions suggestive of FMD such as vesicular lesions on the comb, wattles, eye lids, and feet. Since chickens are to some extent coprophagous, chickens get infected by ingestion of virus under conditions of natural exposure or their plumage gets contaminated in an infectious environment. Thus, domestic birds kept in free-run systems may serve as virus vectors for short distances. Free-living birds, especially starlings (Sturnus vulgaris), sea gulls (Larus canus), house-sparrows (Passer domesticus) have been successfully experimentally infected and developed vesicular lesions on the skin and mucosal membranes of the mouth. During epizootics of FMD the plumage of these free-living birds can be contaminated with FMD viruses and the virus is spread over long distances during migration periods in spring and autumn. Thus migrating birds may assume an active role in long distance dissemination of FMD viruses. PMID:12395578

  10. Contagious Deposition of Seeds in Spider Monkeys' Sleeping Trees Limits Effective Seed Dispersal in Fragmented Landscapes

    PubMed Central

    González-Zamora, Arturo; Arroyo-Rodríguez, Víctor; Escobar, Federico; Rös, Matthias; Oyama, Ken; Ibarra-Manríquez, Guillermo; Stoner, Kathryn E.; Chapman, Colin A.

    2014-01-01

    The repeated use of sleeping sites by frugivorous vertebrates promotes the deposition and aggregation of copious amounts of seeds in these sites. This spatially contagious pattern of seed deposition has key implications for seed dispersal, particularly because such patterns can persist through recruitment. Assessing the seed rain patterns in sleeping sites thus represents a fundamental step in understanding the spatial structure and regeneration of plant assemblages. We evaluated the seed rain produced by spider monkeys (Ateles geoffroyi) in latrines located beneath 60 sleeping trees in two continuous forest sites (CFS) and three forest fragments (FF) in the Lacandona rainforest, Mexico. We tested for differences among latrines, among sites, and between forest conditions in the abundance, diversity (?-, ?- and, ?-components) and evenness of seed assemblages. We recorded 45,919 seeds ?5 mm (in length) from 68 species. The abundance of seeds was 1.7 times higher in FF than in CFS, particularly because of the dominance of a few plant species. As a consequence, community evenness tended to be lower within FF. ?-diversity of common and dominant species was two times greater among FF than between CFS. Although mean ?-diversity per latrine did not differ among sites, the greater ?-diversity among latrines in CFS increased ?-diversity in these sites, particularly when considering common and dominant species. Our results support the hypothesis that fruit scarcity in FF can ‘force’ spider monkeys to deplete the available fruit patches more intensively than in CFS. This feeding strategy can limit the effectiveness of spider monkeys as seed dispersers in FF, because (i) it can limit the number of seed dispersers visiting such fruit patches; (ii) it increases seed dispersal limitation; and (iii) it can contribute to the floristic homogenization (i.e., reduced ?-diversity among latrines) in fragmented landscapes. PMID:24586705

  11. Epidemic spreading in time-varying community networks

    NASA Astrophysics Data System (ADS)

    Ren, Guangming; Wang, Xingyuan

    2014-06-01

    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 qc. The epidemic will survive when q > qc and die when q < qc. These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure.

  12. Prevent the Spread of Zoonotic Diseases (Spanish) 

    E-print Network

    Pena, Josefa

    2008-11-10

    distinci?n de raza, color, sexo, discapacidad, religi?n, edad u origen nacional. Una cooperaci?n del Sistema Universitario Texas A&M, el Departamento de Agricultura de EE.UU. y las Cortes de Comisionados de los Condados de Texas Producido por Agri...

  13. Reaction spreading on graphs

    NASA Astrophysics Data System (ADS)

    Burioni, Raffaella; Chibbaro, Sergio; Vergni, Davide; Vulpiani, Angelo

    2012-11-01

    We study reaction-diffusion processes on graphs through an extension of the standard reaction-diffusion equation starting from first principles. We focus on reaction spreading, i.e., on the time evolution of the reaction product M(t). At variance with pure diffusive processes, characterized by the spectral dimension ds, the important quantity for reaction spreading is found to be the connectivity dimension dl. Numerical data, in agreement with analytical estimates based on the features of n independent random walkers on the graph, show that M(t)˜tdl. In the case of Erdös-Renyi random graphs, the reaction product is characterized by an exponential growth M(t)˜e?t with ? proportional to ln, where is the average degree of the graph.

  14. Lyme Disease

    MedlinePLUS

    ... ticks can spread the disease to animals and humans through tick bites. These ticks are typically about ... in mood Changes in sleep habits Loss of memory Muscle weakness Causes & Risk Factors Who gets Lyme ...

  15. Delivery of Both Foot-and-Mouth Disease Virus Structural and Nonstructural Antigens Improves Protection of Swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) is the etiological agent of one of the most contagious diseases affecting cloven-hoofed animals and is the most important constraint on trade in live animals and animal products. The current vaccine has limitations when used in disease-free countries including dif...

  16. Effect of foot-and-mouth disease virus on the frequency, phenotype and function of circulating dendritic cells in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) is a highly contagious virus that causes one of the most devastating diseases in cloven-hoofed animals. Disease symptoms in FMDV-infected animals appear within 2 to 3 days of exposure. Dendritic cells (DC) play an essential role in protective immune responses agai...

  17. Positive correlation between replication rate and pathotype of Marek’s disease virus strains in maternal antibody negative chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is a highly contagious lymphoproliferative disease of chickens associated with large economic losses worldwide. The etiological agent, Marek’s disease virus (MDV), can be divided into three pathotypes: virulent (v), very virulent (vv), and very virulent plus (vv+). While previou...

  18. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...do to protect livestock from exposure to disease? 166.310 Section 166.310 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  19. 25 CFR 161.206 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...do to protect livestock from exposure to disease? 161.206 Section 161.206 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  20. 25 CFR 161.206 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...do to protect livestock from exposure to disease? 161.206 Section 161.206 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  1. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...do to protect livestock from exposure to disease? 166.310 Section 166.310 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  2. 25 CFR 161.206 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...do to protect livestock from exposure to disease? 161.206 Section 161.206 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  3. 25 CFR 161.206 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...do to protect livestock from exposure to disease? 161.206 Section 161.206 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  4. 25 CFR 161.206 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...do to protect livestock from exposure to disease? 161.206 Section 161.206 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  5. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...do to protect livestock from exposure to disease? 166.310 Section 166.310 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  6. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...do to protect livestock from exposure to disease? 166.310 Section 166.310 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  7. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...do to protect livestock from exposure to disease? 166.310 Section 166.310 Indians...do to protect livestock from exposure to disease? In accordance with applicable law...infected with contagious or infectious diseases; and (c) Restrict the movement...

  8. The Creation of a Contagious H5N1 Influenza Virus: Implications for the Education of Life Scientists.

    PubMed

    Novossiolova, Tatyana; Minehata, Masamichi; Dando, Malcolm

    2012-01-01

    The paper contends that the ongoing controversy surrounding the creation of a contagious H5N1 influenza virus has already exposed the severe limitations of the possibility of preventing the hostile misuse of the life sciences by dint of oversight of proposals and publications. It further argues that in order to prevent the potential wholesale militarisation of the life sciences, it is essential that life scientists become aware of their responsibilities within the context of the Biological and Toxin Weapons Convention (BTWC) and actively contribute their expertise to strengthening the biological weapons non-proliferation regime . PMID:22984642

  9. Department of Mathematics and Statistics Colloquium Modeling the Spread of Waterborne

    E-print Network

    Arnold, Elizabeth A.

    Department of Mathematics and Statistics Colloquium Modeling the Spread of Waterborne Disease in mathematical epidemiology. Many factors influencing disease transmission vary across populations and across different spatial scales. Many results exist for how heterogeneity affects the spread of disease for SIR

  10. Hybrid spread spectrum radio system

    DOEpatents

    Smith, Stephen F. (London, TN) [London, TN; Dress, William B. (Camas, WA) [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  11. Recent origin and spread of a common Lithuanian mutation, G197del LDLR, causing familial hypercholesterolemia: positive selection is not always necessary to account for disease incidence among Ashkenazi Jews.

    PubMed

    Durst, R; Colombo, R; Shpitzen, S; Avi, L B; Friedlander, Y; Wexler, R; Raal, F J; Marais, D A; Defesche, J C; Mandelshtam, M Y; Kotze, M J; Leitersdorf, E; Meiner, V

    2001-05-01

    G197del is the most prevalent LDL receptor (LDLR) mutation causing familial hypercholesterolemia (FH) in Ashkenazi Jew (AJ) individuals. The purpose of this study was to determine the origin, age, and population distribution of G197del, as well as to explore environmental and genetic effects on disease expression. Index cases from Israel (n=46), South Africa (n=24), Russia (n=7), The Netherlands (n=1), and the United States (n=1) were enlisted. All trace their ancestry to Lithuania. A highly conserved haplotype (D19S221:104-D19S865:208-D19S413:74) was identified in G197del chromosomes, suggesting the occurrence of a common founder. When two methods were used for analysis of linkage disequilibrium (LD) between flanking polymorphic markers and the disease locus and for the study of the decay of LD over time, the estimated age of the deletion was found to be 20 +/- 7 generations (the 95% confidence interval is 15-26 generations), so that the most recent common ancestor of the mutation-bearing chromosomes would date to the 14th century. This corresponds with the founding of the Jewish community of Lithuania (1338 a.d.), as well as with the great demographic expansion of AJ individuals in eastern Europe, which followed this settlement. The penetrance of mutation-linked severe hypercholesterolemia is high (94% of heterozygotes have a baseline concentration of LDL cholesterol (LDL-C) that is >160 mg/dl), and no significant differences in the mean baseline lipid level of G197del carriers from different countries were found. Polymorphisms of apolipoprotein E and of scavenger-receptor class B type I were observed to have minor effects on the plasma lipid profile. With respect to determinative genetic influences on the biochemical phenotype, there is no evidence that could support the possibility of a selective evolutionary metabolic advantage. Therefore, the founder effect in a rapidly expanding population from a limited number of families remains a simple, parsimonious hypothesis explaining the spread of G197del-LDLR-linked FH in AJ individuals. PMID:11309683

  12. How the devil facial tumor disease escapes host immune responses.

    PubMed

    Siddle, Hannah V; Kaufman, Jim

    2013-08-01

    The devil facial tumor disease (DFTD) is a contagious cancer that has recently emerged among Tasmanian devils, rapidly decimating the population. We have recently discovered that DFTD cells lose the expression MHC molecules on the cell surface, explaining how this tumor avoids recognition by host CD8(+) T cells. PMID:24083079

  13. Natural Killer Cells in Foot-and-Mouth Disease Virus Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. Immunological knowledge required to design a rational vaccine against FMDV is presently limited. We examined the reactivity of swine and cattle NK cells following infection for their capability to express intracell...

  14. Genome-Wide SNP Association Analysis for Loci Conferring Marek's Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is a T cell lymphoma of domestic chickens caused by Marek’s disease virus (MDV), a highly oncogenic and contagious cell-associated alpha-herpesvirus. Since the 1970s, MD has been controlled by vaccination. However, due to continuous viral evolution with increasing virulence, and...

  15. Did ice-age bovids spread tuberculosis?

    NASA Astrophysics Data System (ADS)

    Rothschild, Bruce M.; Martin, Larry D.

    2006-11-01

    Pathognomonic metacarpal undermining is a skeletal pathology that has been associated with Mycobacterium tuberculosis in bovids. Postcranial artiodactyl, perissodactyl, and carnivore skeletons were examined in major university and museum collections of North America and Europe for evidence of this and other pathology potentially attributable to tuberculosis. Among nonproboscidean mammals from pre-Holocene North America, bone lesions indicative of tuberculosis were restricted to immigrant bovids from Eurasia. No bone lesions compatible with diagnosis of tuberculosis were found in large samples of other pre-Holocene (164 Oligocene, 397 Miocene, and 1,041 Plio Pleistocene) North American mammals, including 114 antilocaprids. Given the unchanged frequency of bovid tubercular disease during the Pleistocene, it appears that most did not die from the disease but actually reached an accommodation with it (as did the mastodon) (Rothschild and Laub 2006). Thus, they were sufficiently long-lived to assure greater spread of the disease. The relationships of the proboscidean examples need further study, but present evidence suggests a Holarctic spread of tuberculosis during the Pleistocene, with bovids acting as vectors. While the role of other animals in the transmission of tuberculosis could be considered, the unique accommodation achieved by bovids and mastodons makes them the likely “culprits” in its spread.

  16. Illusory spreading of watercolor

    PubMed Central

    Devinck, Frédéric; Hardy, Joseph L.; Delahunt, Peter B.; Spillmann, Lothar; Werner, John S.

    2008-01-01

    The watercolor effect (WCE) is a phenomenon of long-range color assimilation occurring when a dark chromatic contour delineating a figure is flanked on the inside by a brighter chromatic contour; the brighter color spreads into the entire enclosed area. Here, we determined the optimal chromatic parameters and the cone signals supporting the WCE. To that end, we quantified the effect of color assimilation using hue cancellation as a function of hue, colorimetric purity, and cone modulation of inducing contours. When the inner and outer contours had chromaticities that were in opposite directions in color space, a stronger WCE was obtained as compared with other color directions. Additionally, equal colorimetric purity between the outer and inner contours was necessary to obtain a large effect compared with conditions in which the contours differed in colorimetric purity. However, there was no further increase in the magnitude of the effect when the colorimetric purity increased beyond a value corresponding to an equal vector length between the inner and outer contours. Finally, L–M-cone-modulated WCE was perceptually stronger than S-cone-modulated WCE for our conditions. This last result demonstrates that both L–M-cone and S-cone pathways are important for watercolor spreading. Our data suggest that the WCE depends critically upon the particular spatiochromatic arrangement in the display, with the relative chromatic contrast between the inducing contours being particularly important. PMID:16881793

  17. Rifts in Spreading Wax Layers

    E-print Network

    Rolf Ragnarsson; J. Lewis Ford; Christian D. Santangelo; Eberhard Bodenschatz

    1995-10-19

    We report experimental results on the rift formation between two freezing wax plates. The plates were pulled apart with constant velocity, while floating on the melt, in a way akin to the tectonic plates of the earth's crust. At slow spreading rates, a rift, initially perpendicular to the spreading direction, was found to be stable, while above a critical spreading rate a "spiky" rift with fracture zones almost parallel to the spreading direction developed. At yet higher spreading rates a second transition from the spiky rift to a zig-zag pattern occurred. In this regime the rift can be characterized by a single angle which was found to be dependent on the spreading rate. We show that the oblique spreading angles agree with a simple geometrical model. The coarsening of the zig-zag pattern over time and the three-dimensional structure of the solidified crust are also discussed.

  18. Did vaccination slow the spread of bluetongue in France?

    PubMed

    Pioz, Maryline; Guis, Hélène; Pleydell, David; Gay, Emilie; Calavas, Didier; Durand, Benoît; Ducrot, Christian; Lancelot, Renaud

    2014-01-01

    Vaccination is one of the most efficient ways to control the spread of infectious diseases. Simulations are now widely used to assess how vaccination can limit disease spread as well as mitigate morbidity or mortality in susceptible populations. However, field studies investigating how much vaccines decrease the velocity of epizootic wave-fronts during outbreaks are rare. This study aimed at investigating the effect of vaccination on the propagation of bluetongue, a vector-borne disease of ruminants. We used data from the 2008 bluetongue virus serotype 1 (BTV-1) epizootic of southwest France. As the virus was newly introduced in this area, natural immunity of livestock was absent. This allowed determination of the role of vaccination in changing the velocity of bluetongue spread while accounting for environmental factors that possibly influenced it. The average estimated velocity across the country despite restriction on animal movements was 5.4 km/day, which is very similar to the velocity of spread of the bluetongue virus serotype 8 epizootic in France also estimated in a context of restrictions on animal movements. Vaccination significantly reduced the propagation velocity of BTV-1. In comparison to municipalities with no vaccine coverage, the velocity of BTV-1 spread decreased by 1.7 km/day in municipalities with immunized animals. For the first time, the effect of vaccination has been quantified using data from a real epizootic whilst accounting for environmental factors known to modify the velocity of bluetongue spread. Our findings emphasize the importance of vaccination in limiting disease spread across natural landscape. Finally, environmental factors, specifically those related to vector abundance and activity, were found to be good predictors of the velocity of BTV-1 spread, indicating that these variables need to be adequately accounted for when evaluating the role of vaccination on bluetongue spread. PMID:24465562

  19. Did Vaccination Slow the Spread of Bluetongue in France?

    PubMed Central

    Pioz, Maryline; Guis, Hélène; Pleydell, David; Gay, Emilie; Calavas, Didier; Durand, Benoît; Ducrot, Christian; Lancelot, Renaud

    2014-01-01

    Vaccination is one of the most efficient ways to control the spread of infectious diseases. Simulations are now widely used to assess how vaccination can limit disease spread as well as mitigate morbidity or mortality in susceptible populations. However, field studies investigating how much vaccines decrease the velocity of epizootic wave-fronts during outbreaks are rare. This study aimed at investigating the effect of vaccination on the propagation of bluetongue, a vector-borne disease of ruminants. We used data from the 2008 bluetongue virus serotype 1 (BTV-1) epizootic of southwest France. As the virus was newly introduced in this area, natural immunity of livestock was absent. This allowed determination of the role of vaccination in changing the velocity of bluetongue spread while accounting for environmental factors that possibly influenced it. The average estimated velocity across the country despite restriction on animal movements was 5.4 km/day, which is very similar to the velocity of spread of the bluetongue virus serotype 8 epizootic in France also estimated in a context of restrictions on animal movements. Vaccination significantly reduced the propagation velocity of BTV-1. In comparison to municipalities with no vaccine coverage, the velocity of BTV-1 spread decreased by 1.7 km/day in municipalities with immunized animals. For the first time, the effect of vaccination has been quantified using data from a real epizootic whilst accounting for environmental factors known to modify the velocity of bluetongue spread. Our findings emphasize the importance of vaccination in limiting disease spread across natural landscape. Finally, environmental factors, specifically those related to vector abundance and activity, were found to be good predictors of the velocity of BTV-1 spread, indicating that these variables need to be adequately accounted for when evaluating the role of vaccination on bluetongue spread. PMID:24465562

  20. Axonal and Transynaptic Spread of Prions

    PubMed Central

    Shearin, Harold

    2014-01-01

    ABSTRACT Natural transmission of prion diseases depends upon the spread of prions from the nervous system to excretory or secretory tissues, but the mechanism of prion transport in axons and into peripheral tissue is unresolved. Here, we examined the temporal and spatial movement of prions from the brain stem along cranial nerves into skeletal muscle as a model of axonal transport and transynaptic spread. The disease-specific isoform of the prion protein, PrPSc, was observed in nerve fibers of the tongue approximately 2 weeks prior to PrPSc deposition in skeletal muscle. Initially, PrPSc deposits had a small punctate pattern on the edge of muscle cells that colocalized with synaptophysin, a marker for the neuromuscular junction (NMJ), in >50% of the cells. At later time points PrPSc was widely distributed in muscle cells, but <10% of prion-infected cells exhibited PrPSc deposition at the NMJ, suggesting additional prion replication and dissemination within muscle cells. In contrast to the NMJ, PrPSc was not associated with synaptophysin in nerve fibers but was found to colocalize with LAMP-1 and cathepsin D during early stages of axonal spread. We propose that PrPSc-bound endosomes can lead to membrane recycling in which PrPSc is directed to the synapse, where it either moves across the NMJ into the postsynaptic muscle cell or induces PrPSc formation on muscle cells across the NMJ. IMPORTANCE Prion diseases are transmissible and fatal neurodegenerative diseases in which prion dissemination to excretory or secretory tissues is necessary for natural disease transmission. Despite the importance of this pathway, the cellular mechanism of prion transport in axons and into peripheral tissue is unresolved. This study demonstrates anterograde spread of prions within nerve fibers prior to infection of peripheral synapses (i.e., neuromuscular junction) and infection of peripheral tissues (i.e., muscle cells). Within nerve fibers prions were associated with the endosomal-lysosomal pathway prior to entry into muscle cells. Since early prion spread is anterograde and endosome-lysosomal movement within axons is primarily retrograde, these findings suggest that endosome-bound prions may have an alternate fate that directs prions to the peripheral synapse. PMID:24850738

  1. Lesion of the Olfactory Epithelium Accelerates Prion Neuroinvasion and Disease Onset when Prion Replication Is Restricted to Neurons

    PubMed Central

    Crowell, Jenna; Wiley, James A.; Bessen, Richard A.

    2015-01-01

    Natural prion diseases of ruminants are moderately contagious and while the gastrointestinal tract is the primary site of prion agent entry, other mucosae may be entry sites in a subset of infections. In the current study we examined prion neuroinvasion and disease induction following disruption of the olfactory epithelium in the nasal mucosa since this site contains environmentally exposed olfactory sensory neurons that project directly into the central nervous system. Here we provide evidence for accelerated prion neuroinvasion and clinical onset from the olfactory mucosa after disruption and regeneration of the olfactory epithelium and when prion replication is restricted to neurons. In transgenic mice with neuron restricted replication of prions, there was a reduction in survival when the olfactory epithelium was disrupted prior to intranasal inoculation and there was >25% decrease in the prion incubation period. In a second model, the neurotropic DY strain of transmissible mink encephalopathy was not pathogenic in hamsters by the nasal route, but 50% of animals exhibited brain infection and/or disease when the olfactory epithelium was disrupted prior to intranasal inoculation. A time course analysis of prion deposition in the brain following loss of the olfactory epithelium in models of neuron-restricted prion replication suggests that neuroinvasion from the olfactory mucosa is via the olfactory nerve or brain stem associated cranial nerves. We propose that induction of neurogenesis after damage to the olfactory epithelium can lead to prion infection of immature olfactory sensory neurons and accelerate prion spread to the brain. PMID:25822718

  2. Multiple Lattice Model for Influenza Spreading

    PubMed Central

    Liccardo, Antonella; Fierro, Annalisa

    2015-01-01

    Behavioral differences among age classes, together with the natural tendency of individuals to prefer contacts with individuals of similar age, naturally point to the existence of a community structure in the population network, in which each community can be identified with a different age class. Data on age-dependent contact patterns also reveal how relevant is the role of the population age structure in shaping the spreading of an infectious disease. In the present paper we propose a simple model for epidemic spreading, in which a contact network with an intrinsic community structure is coupled with a simple stochastic SIR model for the epidemic spreading. The population is divided in 4 different age-communities and hosted on a multiple lattice, each community occupying a specific age-lattice. Individuals are allowed to move freely to nearest neighbor empty sites on the age-lattice. Different communities are connected with each other by means of inter-lattices edges, with a different number of external links connecting different age class populations. The parameters of the contact network model are fixed by requiring the simulated data to fully reproduce the contact patterns matrices of the Polymod survey. The paper shows that adopting a topology which better implements the age-class community structure of the population, one gets a better agreement between experimental contact patterns and simulated data, and this also improves the accordance between simulated and experimental data on the epidemic spreading. PMID:26513580

  3. Systemic foot-and-mouth disease vaccination in cattle promotes specific antibody secreting cells at the respiratory tract and triggers local anamnestic-compatible responses upon aerosol infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot and mouth disease (FMD) is a highly contagious viral disease affecting biungulate species. Commercial vaccines, formulated with inactivated whole FMD virus (FMDV) particles, are regularly used worldwide in regions recognized as free from the disease. Here, we studied the generation of antibody ...

  4. Repeated exposure to 5D9, an inhibitor of 3D polymerase, effectively limits the replication of Foot-and-Mouth Disease Virus in host cells.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-Mouth Disease (FMD) is a highly contagious disease of livestock caused by a highly variable RNA virus that has seven serotypes and more than sixty subtypes. Both prophylactic and post-infection means of controlling the disease outbreak, including universally applicable vaccines and emergenc...

  5. A new kinetic model to discuss the control of panic spreading in emergency

    NASA Astrophysics Data System (ADS)

    Chen, Guanghua; Shen, Huizhang; Chen, Guangming; Ye, Teng; Tang, Xiangbin; Kerr, Naphtali

    2015-01-01

    Individual panic behavior during an emergency is contagious. It often leads to collective panic behavior, which can be disruptive and even disastrous if handled incorrectly. In this paper, a novel kinetic model is developed to describe the dynamics of panic spreading in a real emergency. The global dynamics of the proposed model are analyzed by using the method of Lyapunov function and the Poincarè-Bendixson property, and the obtained theoretical results are numerically validated. The Runge-Kutta method is used for numerical simulations, and these simulations are used to investigate the impact of corresponding management strategies on the containment of individual panic behavior. Meanwhile, the implications of these simulation results are discussed with the "2011 Xiangshui chemical explosion rumor" event. Finally, some recommendations for emergency management agencies are put forward by us to reduce individual panic behavior.

  6. Spreading convulsions, spreading depolarization and epileptogenesis in human cerebral cortex

    PubMed Central

    Major, Sebastian; Pannek, Heinz-Wolfgang; Woitzik, Johannes; Scheel, Michael; Wiesenthal, Dirk; Martus, Peter; Winkler, Maren K.L.; Hartings, Jed A.; Fabricius, Martin; Speckmann, Erwin-Josef; Gorji, Ali

    2012-01-01

    Spreading depolarization of cells in cerebral grey matter is characterized by massive ion translocation, neuronal swelling and large changes in direct current-coupled voltage recording. The near-complete sustained depolarization above the inactivation threshold for action potential generating channels initiates spreading depression of brain activity. In contrast, epileptic seizures show modest ion translocation and sustained depolarization below the inactivation threshold for action potential generating channels. Such modest sustained depolarization allows synchronous, highly frequent neuronal firing; ictal epileptic field potentials being its electrocorticographic and epileptic seizure its clinical correlate. Nevertheless, Leão in 1944 and Van Harreveld and Stamm in 1953 described in animals that silencing of brain activity induced by spreading depolarization changed during minimal electrical stimulations. Eventually, epileptic field potentials were recorded during the period that had originally seen spreading depression of activity. Such spreading convulsions are characterized by epileptic field potentials on the final shoulder of the large slow potential change of spreading depolarization. We here report on such spreading convulsions in monopolar subdural recordings in 2 of 25 consecutive aneurismal subarachnoid haemorrhage patients in vivo and neocortical slices from 12 patients with intractable temporal lobe epilepsy in vitro. The in vitro results suggest that ?-aminobutyric acid-mediated inhibition protects from spreading convulsions. Moreover, we describe arterial pulse artefacts mimicking epileptic field potentials in three patients with subarachnoid haemorrhage that ride on the slow potential peak. Twenty-one of the 25 subarachnoid haemorrhage patients (84%) had 656 spreading depolarizations in contrast to only three patients (12%) with 55 ictal epileptic events isolated from spreading depolarizations. Spreading depolarization frequency and depression periods per 24?h recording episodes showed an early and a delayed peak on Day 7. Patients surviving subarachnoid haemorrhage with poor outcome at 6 months showed significantly higher total and peak numbers of spreading depolarizations and significantly longer total and peak depression periods during the electrocorticographic monitoring than patients with good outcome. In a semi-structured telephone interview 3 years after the initial haemorrhage, 44% of the subarachnoid haemorrhage survivors had developed late post-haemorrhagic seizures requiring anti-convulsant medication. In those patients, peak spreading depolarization number had been significantly higher [15.1 (11.4–30.8) versus 7.0 (0.8–11.2) events per day, P?=?0.045]. In summary, monopolar recordings here provided unequivocal evidence of spreading convulsions in patients. Hence, practically all major pathological cortical network events in animals have now been observed in people. Early spreading depolarizations may indicate a risk for late post-haemorrhagic seizures. PMID:22120143

  7. Chikungunya: Evolutionary history and recent epidemic spread.

    PubMed

    Weaver, Scott C; Forrester, Naomi L

    2015-08-01

    Chikungunya virus (CHIKV) has a long history of emergence into urban transmission cycles from its ancestral, enzootic, sylvatic foci in Sub-Saharan Africa, most recently spreading to the Americas beginning in 2013. Since 2004, reemergence has resulted in millions of cases of severe, debilitating and often chronic arthralgia on five continents. Here, we review this history based on phylogenetic studies, and discuss probable future spread and disease in the Americas. We also discuss a series of mutations in the recently emerged Indian Ocean Lineage that has adapted the virus for transmission for the first time by the Aedes albopictus urban mosquito vector, and compare CHIKV to other arboviruses with and without similar histories of urbanization. This article forms part of a symposium in Antiviral Research on "Chikungunya discovers the New World." PMID:25979669

  8. POTENTIAL ROLE OF FLIES IN THE PERSISTENCE AND DISPERSAL OF EXOTIC NEWCASTLE DISEASE VIRUS IN SOUTHERN CALIFORNIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic Newcastle Disease (END) is a highly virulent and contagious disease affecting poultry and other birds with the potential of causing 100% mortality in unvaccinated poultry. Transmission of END virus to susceptible birds is primarily thought to occur via direct contact with infected birds or in...

  9. Early detection of foot-and-mouth disease virus from infected cattle using a dry filter air sampling system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is a highly contagious livestock disease of high economic impact. Early detection of FMD virus (FMDV) is fundamental for rapid outbreak control. Air sampling collection has been demonstrated as a useful technique for detection of FMDV RNA in infected animals, related to ...

  10. Analysis of foot-and-mouth disease virus integrin receptor expression in tissues from naive and infected cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals principally affecting cattle, pigs and sheep. FMD virus (FMDV) uses the alphaVbeta1, alphaVbeta3, alphaVbeta6 and alphaVbeta8 integrins as receptors in vitro via a highly conserved arginine-glycine-aspartic ac...

  11. Poly ICLC increases the potency of a replication-defective human adenovirus vectored foot-and-mouth disease vaccine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) causes a highly contagious disease of cloven-hoofed animals. We have previously demonstrated that a replication-defective human adenovirus 5 vector carrying the FMDV capsid coding region of serotype A24 Cruzeiro (Ad5-CI-A24-2B) protects swine and cattle against FM...

  12. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... exposure to disease? 166.310 Section 166.310 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR... protect livestock from exposure to disease? In accordance with applicable law, permittees must: (a) Vaccinate livestock; (b) Treat all livestock exposed to or infected with contagious or infectious...

  13. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... exposure to disease? 166.310 Section 166.310 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR... protect livestock from exposure to disease? In accordance with applicable law, permittees must: (a) Vaccinate livestock; (b) Treat all livestock exposed to or infected with contagious or infectious...

  14. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... exposure to disease? 166.310 Section 166.310 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR... protect livestock from exposure to disease? In accordance with applicable law, permittees must: (a) Vaccinate livestock; (b) Treat all livestock exposed to or infected with contagious or infectious...

  15. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... exposure to disease? 166.310 Section 166.310 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR... protect livestock from exposure to disease? In accordance with applicable law, permittees must: (a) Vaccinate livestock; (b) Treat all livestock exposed to or infected with contagious or infectious...

  16. 25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... exposure to disease? 166.310 Section 166.310 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR... protect livestock from exposure to disease? In accordance with applicable law, permittees must: (a) Vaccinate livestock; (b) Treat all livestock exposed to or infected with contagious or infectious...

  17. Homodimerization of Marek's disease virus encoded Meq protein is not sufficient for transformation of lymphocytes in chicken

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease virus (MDV), the etiologic agent of Marek’s disease, is a potent oncogenic herpesvirus. MDV is highly contagious and elicits a rapid onset of malignant T-cell lymphomas in chickens within several weeks after infection. MDV codes for an oncoprotein, Meq, which shares resemblance wit...

  18. RECOVERY OF EXOTIC NEWCASTLE DISEASE VIRUS (ENDV) FROM FIELD COLLECTED FLIES AND EXPERIMENTAL ENDV INFECTIONS OF THREE ARTHROPOD SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic Newcastle Disease (END) is a highly virulent and contagious disease affecting poultry and other birds with the potential of causing 100% mortality in unvaccinated poultry. Transmission of END virus to susceptible birds is primarily thought to occur via direct contact with infected birds or i...

  19. PATHOGENIC CHARACTERISTICS OF THE KOREAN 2002 ISOLATE OF FOOT-AND-MOUTH DISEASE VIRUS SEROTYPE O IN PIGS AND CATTLE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experimental infection of susceptible cattle and pigs with foot-and-mouth disease virus (FMDV) O/SKN/AS/2002 pig strain indicates that this virus causes a disease that is highly virulent and contagious in swine, but causes a very limited infection in bovine. Pigs directly inoculated with, or expose...

  20. Islamic Universities Spread through Africa

    ERIC Educational Resources Information Center

    Lindow, Megan

    2007-01-01

    This article reports on new universities for Muslims, many supported by groups in the Middle East, which are spreading through the sub-Saharan region. The Islamic University in Uganda is a prime example of a new kind of institution that has slowly been spreading its way across the continent. Embracing both conservative Muslim values and modern…

  1. Increased Spreading Activation in Depression

    ERIC Educational Resources Information Center

    Foster, Paul S.; Yung, Raegan C.; Branch, Kaylei K.; Stringer, Kristi; Ferguson, Brad J.; Sullivan, William; Drago, Valeria

    2011-01-01

    The dopaminergic system is implicated in depressive disorders and research has also shown that dopamine constricts lexical/semantic networks by reducing spreading activation. Hence, depression, which is linked to reductions of dopamine, may be associated with increased spreading activation. However, research has generally found no effects of…

  2. Bone Marrow Diseases

    MedlinePLUS

    ... blood clotting. If you have a bone marrow disease, there are problems with the stem cells or ... marrow doesn't make red blood cells. Other diseases, such as lymphoma, can spread into the bone ...

  3. The contagious nature of imprisonment: an agent-based model to explain racial disparities in incarceration rates

    PubMed Central

    Lum, Kristian; Swarup, Samarth; Eubank, Stephen; Hawdon, James

    2014-01-01

    We build an agent-based model of incarceration based on the susceptible–infected–suspectible (SIS) model of infectious disease propagation. Our central hypothesis is that the observed racial disparities in incarceration rates between Black and White Americans can be explained as the result of differential sentencing between the two demographic groups. We demonstrate that if incarceration can be spread through a social influence network, then even relatively small differences in sentencing can result in large disparities in incarceration rates. Controlling for effects of transmissibility, susceptibility and influence network structure, our model reproduces the observed large disparities in incarceration rates given the differences in sentence lengths for White and Black drug offenders in the USA without extensive parameter tuning. We further establish the suitability of the SIS model as applied to incarceration by demonstrating that the observed structural patterns of recidivism are an emergent property of the model. In fact, our model shows a remarkably close correspondence with California incarceration data. This work advances efforts to combine the theories and methods of epidemiology and criminology. PMID:24966237

  4. Foot-and-mouth disease virus infection of dendritic cells triggers phosphorylation of ERK1/2 inducing class I presentation and apoptosis.

    PubMed

    Langellotti, Cecilia; Cesar, Gonzalo; Soria, Ivana; Quattrocchi, Valeria; Jancic, Carolina; Zamorano, Patricia; Vermeulen, Mónica

    2015-09-11

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals. This pathology is caused by foot-and-mouth disease virus (FMDV). Over time, the development of vaccines to prevent the spread of this illness became essential. Vaccines currently used contain the inactivated form of the virus. However, vaccination generates an immune response different to that induced by the infection. We investigated whether these differences are related to intracellular mechanisms on dendritic cells (DCs). As a result, we demonstrated that the internalization of infective virus triggered the phosphorylation of ERK1/2, which was involved in the activation of caspase-9, the intrinsic pathway of apoptosis and the delivery of viral peptides on MHC class I molecules. While, inactivated virus (iFMDV) did not affect this pathway or any function mediated by its activation. As described, infectious virus in DCs was also associated to autophagy LC3 protein and was associated to lysosomal protein Lamp-2; contrary to observe for the iFMDV. Strikingly, the processing of viral antigens to accommodate in class I molecules does not appear to involve the proteasome. Finally, this increased presentation promotes a specific cytotoxic response against infectious virus. PMID:26212005

  5. Economic Impacts of Potential Foot and Mouth Disease Agro-terrorism in the United States: A Computable General Equilibrium Analysis

    SciTech Connect

    Oladosu, Gbadebo A; Rose, Adam; Bumsoo, Lee

    2013-01-01

    The foot and mouth disease (FMD) virus has high agro-terrorism potential because it is contagious, can be easily transmitted via inanimate objects and can be spread by wind. An outbreak of FMD in developed countries results in massive slaughtering of animals (for disease control) and disruptions in meat supply chains and trade, with potentially large economic losses. Although the United States has been FMD-free since 1929, the potential of FMD as a deliberate terrorist weapon calls for estimates of the physical and economic damage that could result from an outbreak. This paper estimates the economic impacts of three alternative scenarios of potential FMD attacks using a computable general equilibrium (CGE) model of the US economy. The three scenarios range from a small outbreak successfully contained within a state to a large multi-state attack resulting in slaughtering of 30 percent of the national livestock. Overall, the value of total output losses in our simulations range between $37 billion (0.15% of 2006 baseline economic output) and $228 billion (0.92%). Major impacts stem from the supply constraint on livestock due to massive animal slaughtering. As expected, the economic losses are heavily concentrated in agriculture and food manufacturing sectors, with losses ranging from $23 billion to $61 billion in the two industries.

  6. Presunrise spread F at Fortaleza

    NASA Astrophysics Data System (ADS)

    MacDougall, J. W.; Abdu, M. A.; Jayachandran, P. T.; Cecile, J.-F.; Batista, I. S.

    1998-10-01

    At Fortaleza, Brazil, in the equatorial zone about 400 km south of the magnetic equator a presunrise (secondary) maximum of spread F occurrence is observed during sunspot minimum and, in particular, during December solstice. The spread F takes the form of patches of irregularities that are convecting eastwards at ~50 ms-1. Most of the patches are collocated with bottomside bulges of the ionosphere. Our measurements indicate that these bottomside bulges are unstable due to a gradient-drift instability that is slowly growing and produces the spread F. The bulges themselves seem to be evidence of a Rayleigh-Taylor instability proces.

  7. Primary Gonorrhea Infection

    MedlinePLUS

    ... seen in this image. Overview Gonorrhea is a sexually transmitted disease caused by the bacterium Neisseria gonorrhea . It is a contagious sexually transmitted disease spread by unprotected oral, vaginal, or anal sex ...

  8. Antibody inhibition of human cytomegalovirus spread in epithelial cell cultures

    PubMed Central

    Cui, Xiaohong; Lee, Ronzo; Adler, Stuart P.; McVoy, Michael A.

    2013-01-01

    Anti-cytomegalovirus (CMV) antibodies reduce the incidence of CMV transmission and ameliorate the severity of CMV-associated disease. Neutralizing activity, measured as the ability of antibodies to prevent entry of cell-free virus, is an important component of natural immunity. However, in vivo CMV amplification may occur mainly via spread between adjacent cells within tissues. Thus, inhibition of cell-to-cell spread may be important when evaluating therapeutic antibodies or humoral responses to infection or immunization. In vitro CMV cell-to-cell spread is largely resistant to antibodies in fibroblast cultures but sensitive in endothelial cell cultures. In the present study antibodies in CMV hyperimmuneglobulin or seropositive human sera inhibited CMV cell-to-cell spread in epithelial cell cultures. Spread inhibition activity was quantitated with a GFP reporter assay employing GFP-tagged epithelialtropic variants of CMV strains Towne or AD169. Measurement of spread inhibition provides an additional parameter for the evaluation of candidate vaccines or immunotherapeutics and to further characterize the role of antibodies in controlling CMV transmission and disease. PMID:23669101

  9. Roles of Ties in Spreading

    E-print Network

    Cui, Ai-Xiang; Zhou, Tao

    2012-01-01

    Background: Controlling global epidemics in the real world and accelerating information propagation in the artificial world are of great significance, which have activated an upsurge in the studies on networked spreading dynamics. Lots of efforts have been made to understand the impacts of macroscopic statistics (e.g., degree distribution and average distance) and mesoscopic structures (e.g., communities and rich clubs) on spreading processes while the microscopic elements are less concerned. In particular, roles of ties are not yet clear to the academic community. Methodology/Principle Findings: Every edges is stamped by its strength that is defined solely based on the local topology. According to a weighted susceptible-infected-susceptible model, the steady-state infected density and spreading speed are respectively optimized by adjusting the relationship between edge's strength and spreading ability. Experiments on six real networks show that the infected density is increased when strong ties are favored i...

  10. Prevent the Spread of Norovirus

    MedlinePLUS

    ... kitchen Carefully rinse fruits and vegetables, and cook oysters and other shellfish thoroughly before eating. Do not ... not to shake them —to avoid spreading virus. If available, wear rubber or disposable gloves while ...

  11. Imperfect spreading on temporal networks

    NASA Astrophysics Data System (ADS)

    Gueuning, Martin; Delvenne, Jean-Charles; Lambiotte, Renaud

    2015-11-01

    We study spreading on networks where the contact dynamics between the nodes is governed by a random process and where the inter-contact time distribution may differ from the exponential. We consider a process of imperfect spreading, where transmission is successful with a determined probability at each contact. We first derive an expression for the inter-success time distribution, determining the speed of the propagation, and then focus on a problem related to epidemic spreading, by estimating the epidemic threshold in a system where nodes remain infectious during a finite, random period of time. Finally, we discuss the implications of our work to design an efficient strategy to enhance spreading on temporal networks.

  12. Spreading dynamics of polymer nanodroplets.

    SciTech Connect

    Webb, Edmund Blackburn, III; Grest, Gary Stephen; Heine, David R.

    2003-08-01

    The spreading of polymer droplets is studied using molecular dynamics simulations. To study the dynamics of both the precursor foot and the bulk droplet, large hemispherical drops of 200 000 monomers are simulated using a bead-spring model for polymers of chain length 10, 20, and 40 monomers per chain. We compare spreading on flat and atomistic surfaces, chain length effects, and different applications of the Langevin and dissipative particle dynamics thermostats. We find diffusive behavior for the precursor foot and good agreement with the molecular kinetic model of droplet spreading using both flat and atomistic surfaces. Despite the large system size and long simulation time relative to previous simulations, we find that even larger systems are required to observe hydrodynamic behavior in the hemispherical spreading droplet.

  13. Chronic wasting disease of cervids.

    PubMed

    Miller, M W; Williams, E S

    2004-01-01

    Chronic wasting disease (CWD) has recently emerged in North America as an important prion disease of captive and free-ranging cervids (species in the deer family). CWD is the only recognized transmissible spongiform encephalopathy (TSE) affecting free-ranging species. Three cervid species, mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and Rocky Mountain elk (Cervus elaphus nelsoni), are the only known natural hosts of CWD. Endemic CWD is well established in southern Wyoming and northern Colorado, and has been present in this 'core area' for two decades or more. Apparently CWD has also infected farmed cervids in numerous jurisdictions, and has probably been endemic in North America's farmed deer and elk for well over a decade. Several free-ranging foci distant to the Colorado-Wyoming core area have been discovered since 2000, and new or intensified surveillance may well identify even more foci of infection. Whether all of the identified captive and free-ranging foci are connected via a common original exposure source remains undetermined. Some of this recently observed 'spread' may be attributable to improved detection or natural movements of infected deer and elk, but more distant range extensions are more likely caused by movements of infected captive deer and elk in commerce, or by some yet unidentified exposure risk factor. Research on CWD over the last 5 years has resulted in a more complete understanding of its pathogenesis and epidemiology. CWD is infectious, transmitting horizontally from infected to susceptible cervids. Early accumulation of PrP(CWD) in alimentary tract-associated lymphoid tissues during incubation suggests agent shedding in feces or saliva as plausible transmission routes. Residual infectivity in contaminated environments also appears to be important in sustaining epidemics. Improved tests allow CWD to be reliably diagnosed long before clinical signs appear. Implications of CWD are not entirely clear at this time. Natural transmission to humans or traditional domestic livestock seems relatively unlikely, but the possibility still evokes public concerns; impacts on wildlife resources have not been determined. Consequently, where CWD is not known to occur surveillance programs and regulations that prevent or reduce the likelihood that CWD will be introduced into these jurisdictions should be encouraged. Where CWD is known to occur, affected jurisdictions are conducting surveillance to estimate and monitor trends in geographic distribution and prevalence, managing deer and elk populations in attempts to limit spread, and developing and evaluating techniques for further controlling and perhaps eradicating CWD. Programs for addressing the challenges of CWD management will require interagency cooperation, commitment of funds and personnel, and applied research. Chronic wasting disease (CWD) is perhaps the most enigmatic of the naturally occurring prion diseases. Although recognized as a transmissible spongiform encephalopathy (TSE) since the late 1970s (Williams and Young 1980, 1982), interest in and concern about CWD has only recently emerged. CWD most closely resembles scrapie in sheep in most respects, but recent media and public reaction to CWD has been more reminiscent of that afforded to bovine spongiform encephalopathy (BSE) less than a decade ago. Yet, with the exception of transmissible mink encephalopathy (TME), CWD is the rarest of the known animal TSEs: fewer than 1,000 cases have been diagnosed worldwide, and all but two of these occurred in North America. CWD is unique among the TSEs in that it affects free-living species (Spraker et al. 1997; Miller et al. 2000). The three natural host species for CWD, mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and Rocky Mountain elk (Cervus elaphus nelsoni), are all in the family Cervidae and native to North America. Like scrapie, CWD is contagious: epidemics are self-sustaining in both captive and free-ranging cervid populations (Miller et al. 1998, 2000). The geographic extent of endemic CWD in free-ra

  14. Epidemic spreading in time-varying community networks

    SciTech Connect

    Ren, Guangming E-mail: ren-guang-ming@163.com; Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 ; Wang, Xingyuan E-mail: ren-guang-ming@163.com

    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?spreading in complex networks with community structure.

  15. Physical Proximity and Spreading in Dynamic Social Networks

    E-print Network

    Stopczynski, Arkadiusz; Lehmann, Sune

    2015-01-01

    Most infectious diseases spread on a dynamic network of human interactions. Recent studies of social dynamics have provided evidence that spreading patterns may depend strongly on detailed micro-dynamics of the social system. We have recorded every single interaction within a large population, mapping out---for the first time at scale---the complete proximity network for a densely-connected system. Here we show the striking impact of interaction-distance on the network structure and dynamics of spreading processes. We create networks supporting close (intimate network, up to ~1m) and longer distance (ambient network, up to ~10m) modes of transmission. The intimate network is fragmented, with weak ties bridging densely-connected neighborhoods, whereas the ambient network supports spread driven by random contacts between strangers. While there is no trivial mapping from the micro-dynamics of proximity networks to empirical epidemics, these networks provide a telling approximation of droplet and airborne modes o...

  16. Flame spread across liquid pools

    NASA Technical Reports Server (NTRS)

    Ross, Howard; Miller, Fletcher; Schiller, David; Sirignano, William A.

    1993-01-01

    For flame spread over liquid fuel pools, the existing literature suggests three gravitational influences: (1) liquid phase buoyant convection, delaying ignition and assisting flame spread; (2) hydrostatic pressure variation, due to variation in the liquid pool height caused by thermocapillary-induced convection; and (3) gas-phase buoyant convection in the opposite direction to the liquid phase motion. No current model accounts for all three influences. In fact, prior to this work, there was no ability to determine whether ignition delay times and flame spread rates would be greater or lesser in low gravity. Flame spread over liquid fuel pools is most commonly characterized by the relationship of the initial pool temperature to the fuel's idealized flash point temperature, with four or five separate characteristic regimes having been identified. In the uniform spread regime, control has been attributed to: (1) gas-phase conduction and radiation; (2) gas-phase conduction only; (3) gas-phase convection and liquid conduction, and most recently (4) liquid convection ahead of the flame. Suggestions were made that the liquid convection was owed to both vuoyancy and thermocapillarity. Of special interest to this work is the determination of whether, and under what conditions, pulsating spread can and will occur in microgravity in the absence of buoyant flows in both phases. The approach we have taken to resolving the importance of buoyancy for these flames is: (1) normal gravity experiments and advanced diagnostics; (2) microgravity experiments; and (3) numerical modelling at arbitrary gravitational level.

  17. Using Mathematical Modelling to Explore Hypotheses about the Role of Bovine Epithelium Structure in Foot-And-Mouth Disease Virus-Induced Cell Lysis

    E-print Network

    Giorgakoudi, Kyriaki; Gubbins, Simon; Ward, John; Juleff, Nicholas; Zhang, Zhidong; Schley, David

    2015-10-02

    Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. FMD virus (FMDV) shows a strong tropism for epithelial cells, and FMD is characterised by cell lysis and the development of vesicular lesions in certain epithelial...

  18. Newcastle disease virus (NDV) recombinants expressing infectious laryngotracheitis virus (ILTV) glycoproteins gB and gD protect chickens against ILTV and NDV challenges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infectious laryngotracheitis (ILT) is a highly contagious acute respiratory disease of chickens caused by infectious laryngotracheitis virus (ILTV). The disease is mainly controlled through biosecurity and vaccination with live-attenuated strains of the virus and vectored vaccines based on turkey he...

  19. Worldwide Spread of Dengue Virus Type 1

    PubMed Central

    Villabona-Arenas, Christian Julián; Zanotto, Paolo Marinho de Andrade

    2013-01-01

    Background DENV-1 is one of the four viral serotypes that causes Dengue, the most common mosquito-borne viral disease of humans. The prevalence of these viruses has grown in recent decades and is now present in more than 100 countries. Limited studies document the spread of DENV-1 over the world despite its importance for human health. Methodology/Principal Findings We used representative DENV-1 envelope gene sequences to unravel the dynamics of viral diffusion under a Bayesian phylogeographic approach. Data included strains from 45 distinct geographic locations isolated from 1944 to 2009. The estimated mean rate of nucleotide substitution was 6.56×10?4 substitutions/site/year. The larger genotypes (I, IV and V) had a distinctive phylogenetic structure and since 1990 they experienced effective population size oscillations. Thailand and Indonesia represented the main sources of strains for neighboring countries. Besides, Asia broadcast lineages into the Americas and the Pacific region that diverged in isolation. Also, a transmission network analysis revealed the pivotal role of Indochina in the global diffusion of DENV-1 and of the Caribbean in the diffusion over the Americas. Conclusions/Significance The study summarizes the spatiotemporal DENV-1 worldwide spread that may help disease control. PMID:23675416

  20. Ebola from emergence to epidemic: the virus and the disease, global preparedness and perspectives.

    PubMed

    Dhama, Kuldeep; Malik, Yashpal Singh; Malik, Satya Veer Singh; Singh, Raj Kumar

    2015-05-01

    Humans constantly encounter threats from many infectious, zoonotic, and devastating pathogens. Outbreaks of severe acute respiratory syndrome (SARS), bird flu, and swine flu posing pandemic threats have compelled health agencies to follow global preparedness for combating the emerging deadly pathogens. The outbreak in West Africa of highly contagious Ebola viral disease (EVD) that started in Guinea in December 2013, assumed global proportions to become the largest outbreak of EVD and the most prominent international health concern. With fatality rates of nearly 50%-90%, it has claimed, as of 11 April 2015, 10,619 human lives out of a total of 25,626 cases reported worldwide. Ebola virus (EBOV), a member of Filoviridae family, is associated with severe, often lethal, hemorrhagic fever disease in humans and animals. The animal hosts, including non-human primates and reservoir hosts (fruit bats), play a significant role in transmission and maintenance of EBOV in nature. Although no approved vaccine for the prevention of EVD currently exists, disease control can be greatly enhanced by timely laboratory confirmation through blood tests using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Adherence to strict sanitary and hygienic measures, monitoring and surveillance of EBOV, as well as quarantine checks on international trade, transport, and visitors from affected countries are mandatory to prevent and control the spread of EVD. This review describes the salient properties of EBOV and the development of novel diagnostics, vaccines, and control strategies for this emerging disease of high public health concern and international emergency. PMID:25989163

  1. Aerial dispersal and multiple-scale spread of epidemics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disease spread has traditionally been described as a traveling wave of constant velocity. However, aerially dispersed pathogens capable of long distance dispersal (LDD) often have dispersal gradients with extended tails that could result in acceleration of the epidemic front over time and space. W...

  2. Bridging a yawning chasm: EEG investigations into the debate concerning the role of the human mirror neuron system in contagious yawning.

    PubMed

    Cooper, Nicholas R; Puzzo, Ignazio; Pawley, Adam D; Bowes-Mulligan, Ruby A; Kirkpatrick, Emma V; Antoniou, Pavlina A; Kennett, Steffan

    2012-06-01

    Ongoing debate in the literature concerns whether there is a link between contagious yawning and the human mirror neuron system (hMNS). One way of examining this issue is with the use of the electroencephalogram (EEG) to measure changes in mu activation during the observation of yawns. Mu oscillations are seen in the alpha bandwidth of the EEG (8-12 Hz) over sensorimotor areas. Previous work has shown that mu suppression is a useful index of hMNS activation and is sensitive to individual differences in empathy. In two experiments, we presented participants with videos of either people yawning or control stimuli. We found greater mu suppression for yawns than for controls over right motor and premotor areas, particularly for those scoring higher on traits of empathy. In a third experiment, auditory recordings of yawns were compared against electronically scrambled versions of the same yawns. We observed greater mu suppression for yawns than for the controls over right lateral premotor areas. Again, these findings were driven by those scoring highly on empathy. The results from these experiments support the notion that the hMNS is involved in contagious yawning, emphasise the link between contagious yawning and empathy, and stress the importance of good control stimuli. PMID:22198677

  3. The role of hybridization in the origin and spread of asexuality in Daphnia.

    PubMed

    Xu, Sen; Innes, David J; Lynch, Michael; Cristescu, Melania E

    2013-09-01

    The molecular mechanisms leading to asexuality remain little understood despite their substantial bearing on why sexual reproduction is dominant in nature. Here, we examine the role of hybridization in the origin and spread of obligate asexuality in Daphnia pulex, arguably the best-documented case of contagious asexuality. Obligately parthenogenetic (OP) clones of D. pulex have traditionally been separated into 'hybrid' (Ldh SF) and 'nonhybrid' (Ldh SS) forms because the lactase dehydrogenase (Ldh) locus distinguishes the cyclically parthenogenetic (CP) lake dwelling Daphnia pulicaria (Ldh FF) from its ephemeral pond dwelling sister species D. pulex (Ldh SS). The results of our population genetic analyses based on microsatellite loci suggest that both Ldh SS and SF OP individuals can originate from the crossing of CP female F1 (D. pulex × D. pulicaria) and backcross with males from OP lineages carrying genes that suppress meiosis specifically in female offspring. In previous studies, a suite of diagnostic markers was found to be associated with OP in Ldh SS D. pulex lineages. Our association mapping supports a similar genetic mechanism for the spread of obligate parthenogenesis in Ldh SF OP individuals. Interestingly, our study shows that CP D. pulicaria carry many of the diagnostic microsatellite alleles associated with obligate parthenogenesis. We argue that the assemblage of mutations that suppress meiosis and underlie obligate parthenogenesis in D. pulex originated due to a unique historical hybridization and introgression event between D. pulex and D. pulicaria. PMID:23879327

  4. The role of hybridization in the origin and spread of asexuality in Daphnia

    PubMed Central

    Xu, Sen; Innes, David J.; Lynch, Michael; Cristescu, Melania E.

    2014-01-01

    The molecular mechanisms leading to asexuality remain little understood despite their substantial bearing on why sexual reproduction is dominant in nature. Here we examine the role of hybridization in the origin and spread of obligate asexuality in Daphnia pulex, arguably the best-documented case of contagious asexuality. Obligately parthenogenetic (OP) clones of D. pulex have traditionally been separated into “hybrid” (Ldh SF) and “non-hybrid” (Ldh SS) forms because the lactase dehydrogenase (Ldh) locus distinguishes the cyclically parthenogenetic (CP) lake dwelling Daphnia pulicaria (Ldh FF) from its ephemeral pond dwelling sister species D. pulex (Ldh SS). The results of our population genetic analyses based on microsatellite loci suggest that both Ldh SS and SF OP individuals can originate from the crossing of CP female F1 (D. pulex × D. pulicaria) and backcrosses with males from OP lineages carrying genes that suppress meiosis specifically in female offspring. In previous studies, a suite of diagnostic markers was found to be associated with OP in Ldh SS D. pulex lineages. Our association mapping supports a similar genetic mechanism for the spread of obligate parthenogenesis in Ldh SF OP individuals. Interestingly, our study shows that CP D. pulicaria carry many of the diagnostic microsatellite alleles associated with obligate parthenogenesis. We argue that the assemblage of mutations that suppress meiosis and underlie obligate parthenogenesis in D. pulex originated due to a unique historical hybridization and introgression event between D. pulex and D. pulicaria. PMID:23879327

  5. FREQUENCY HOPPING SPREAD SPECTRUM DIRECT SEQUENCE SPREAD SPECTRUM

    E-print Network

    Westall, James M.

    of spreading their signals. The range of available frequencies in the ISM2 (Industrial Scientific Medical) band.4GHz ISM band covering 79 channels. Each channel occupies 1Mhz of bandwidth and must hop at the minimum is not to be confused with CDMA. All 802.11 compliant products utilize the same PN code and therefore do not have a set

  6. Spectral and Spread Spectral Teleportation

    SciTech Connect

    Humble, Travis S

    2010-01-01

    We report how quantum information encoded into the spectral degree of freedom of a single-photon state is teleported using a finite spectrally entangled biphoton state. We further demonstrate how the bandwidth of a teleported waveform can be controllably and coherently dilated using a spread spectral variant of teleportation. We present analytical fidelities for spectral and spread spectral teleportation when complex-valued Gaussian states are prepared using a proposed experimental approach, and we discuss the utility of these techniques for integrating broad-bandwidth photonic qubits with narrow-bandwidth receivers in quantum communication systems.

  7. Modelling the spread of Wolbachia in spatially heterogeneous environments

    PubMed Central

    Hancock, Penelope A.; Godfray, H. Charles J.

    2012-01-01

    The endosymbiont Wolbachia infects a large number of insect species and is capable of rapid spread when introduced into a novel host population. The bacteria spread by manipulating their hosts' reproduction, and their dynamics are influenced by the demographic structure of the host population and patterns of contact between individuals. Reaction–diffusion models of the spatial spread of Wolbachia provide a simple analytical description of their spatial dynamics but do not account for significant details of host population dynamics. We develop a metapopulation model describing the spatial dynamics of Wolbachia in an age-structured host insect population regulated by juvenile density-dependent competition. The model produces similar dynamics to the reaction–diffusion model in the limiting case where the host's habitat quality is spatially homogeneous and Wolbachia has a small effect on host fitness. When habitat quality varies spatially, Wolbachia spread is usually much slower, and the conditions necessary for local invasion are strongly affected by immigration of insects from surrounding regions. Spread is most difficult when variation in habitat quality is spatially correlated. The results show that spatial variation in the density-dependent competition experienced by juvenile host insects can strongly affect the spread of Wolbachia infections, which is important to the use of Wolbachia to control insect vectors of human disease and other pests. PMID:22675165

  8. A colorimetric bioassay for high-througput and cost-effectively assessing anti-foot-and-mouth disease virus activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-Mouth Disease virus (FMDV) is one of the most contagious animal viruses and has a devastating effect on livestock industries if an outbreaks occurs, especially in FMD-free countries. The virus is very sensitive to inhibition by type I interferons. Currently, a reported assay to measure FM...

  9. THE SURVIVAL OF FOOT-AND-MOUTH DISEASE VIRUS IN RAW AND PASTEURIZED MILK AND MILK PRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The foot-and-mouth disease (FMD) virus is not a threat to public health, but is highly contagious to cloven-footed animals. The literature reports that FMD virus has a higher thermal resistance in milk than other viruses. The purpose of this paper is to review experiments that were performed to dete...

  10. Using a Bear Put Spread 

    E-print Network

    Bevers, Stan; Amosson, Stephen H.; Waller, Mark L.; Dhuyvetter, Kevin C.

    2008-10-07

    , Mark Waller and Kevin Dhuyvetter* 2 of the two options). The spread gain is limited to the difference between the strike price of the put option bought and the strike price of the put option sold, less commissions and the net cost of the premium...

  11. Verrucae planae spread by electrolysis.

    PubMed

    Petrozzi, J W

    1980-07-01

    The following case report presents a patient in whom flat warts were spread by electrolysis. Since electrolysis is a common procedure, physicians should be aware of such an occurrence. Adequate examination and treatment before the patient undergoes electrolysis can eliminate this unwanted side effect. PMID:7389402

  12. Tuning magnetofluidic spreading in microchannels

    NASA Astrophysics Data System (ADS)

    Wang, Zhaomeng; Varma, V. B.; Wang, Z. P.; Ramanujan, R. V.

    2015-12-01

    Magnetofluidic spreading (MFS) is a phenomenon in which a uniform magnetic field is used to induce spreading of a ferrofluid core cladded by diamagnetic fluidic streams in a three-stream channel. Applications of MFS include micromixing, cell sorting and novel microfluidic lab-on-a-chip design. However, the relative importance of the parameters which govern MFS is still unclear, leading to non-optimal control of MFS. Hence, in this work, the effect of various key parameters on MFS was experimentally and numerically studied. Our multi-physics model, which combines magnetic and fluidic analysis, showed excellent agreement between theory and experiment. It was found that spreading was mainly due to cross-sectional convection induced by magnetic forces, and can be enhanced by tuning various parameters. Smaller flow rate ratio, higher magnetic field, higher core stream or lower cladding stream dynamic viscosity, and larger magnetic particle size can increase MFS. These results can be used to tune magnetofluidic spreading in microchannels.

  13. Using a Bull Call Spread 

    E-print Network

    Bevers, Stan; Amosson, Stephen H.; Waller, Mark L.; Dhuyvetter, Kevin C.

    2008-10-07

    The Bull Call Spread can be used to hedge against or to benefit from a rising market. The user buys a call option at a particular strike price and sells a call option at a higher strike price. Margin requirements, advantages and disadvantages...

  14. Spreading dynamics in complex networks

    NASA Astrophysics Data System (ADS)

    Pei, Sen; Makse, Hernán A.

    2013-12-01

    Searching for influential spreaders in complex networks is an issue of great significance for applications across various domains, ranging from epidemic control, innovation diffusion, viral marketing, and social movement to idea propagation. In this paper, we first display some of the most important theoretical models that describe spreading processes, and then discuss the problem of locating both the individual and multiple influential spreaders respectively. Recent approaches in these two topics are presented. For the identification of privileged single spreaders, we summarize several widely used centralities, such as degree, betweenness centrality, PageRank, k-shell, etc. We investigate the empirical diffusion data in a large scale online social community—LiveJournal. With this extensive dataset, we find that various measures can convey very distinct information of nodes. Of all the users in the LiveJournal social network, only a small fraction of them are involved in spreading. For the spreading processes in LiveJournal, while degree can locate nodes participating in information diffusion with higher probability, k-shell is more effective in finding nodes with a large influence. Our results should provide useful information for designing efficient spreading strategies in reality.

  15. Soil Mineralogy as Factor in Spread of Fusarium Wilt of Banana.

    PubMed

    Stotzky, G; Dawson, J E; Martin, R T; Ter Kuile, C H

    1961-05-12

    A correlation is established between the spread of Fusarium wilt of banana and soil mineralogy. Montmorillonoid-type clay minerals occur in all soils in which disease spread is slow, but, with the exception of two soils, this group of minerals is absent in soils in which it is rapid. PMID:17818209

  16. [Spreading of protein misfolding: A new paradigm in neurology].

    PubMed

    Hauw, J-J; Haïk, S; Duyckaerts, C

    2015-12-01

    Protein misfolding and spreading ("transconformation") are being better understood. Described in Prions diseases, this new paradigm in the field of neurodegenerative disorders and brain aging also implies sporadic inclusion myositis, type 2 diabetes, some cancers, sickle cell disease… Misfolding is transmitted from a protein or peptide to a normally folded one. Often associated with a stress of the endoplasmic reticulum, it may spread along the neurites, following anterograde or retrograde axonal transport. In the central nervous system, it occurs in a few cells and there is invasion of adjacent cells by cell-to-cell spread. Three varieties of protein misfolding occur along neuroanatomical pathways. It can be a 'centripetal' process. The synucleinopathy of Parkinson disease has been carefully studied: the changes first occur in cardiac or enteric plexuses… and reach later on the mesencephalon and neocortex. Thus, skin biopsy might prove a diagnostic tool. Protein misfolding may also occur along 'centrifugal' pathways, from motor cortex to peripheral motor neurons. Examples are provided by SOD and pTDP-43 in Amyotrophic Lateral Sclerosis. Amyloid ? peptide in cerebral aging and Alzheimer's disease also spread from occipital cortex to the brainstem. Lastly, the propagation may remain 'central' for TDP-43 in behavioral variant frontotemporal dementia, following only pathways of the encephalic neural network. This has to be confirmed, however, since the spreading of some proteins (such as tau or A? peptides) has been considered central for a long time and has proved today to involve extracerebral tissues. The complex mechanisms of protein misfolding, still in analysis, include the involvement of chaperone proteins, the formation of very toxic labile proteins molecules (oligomers?), and provide a number of new therapeutic perspectives. PMID:26573331

  17. Wolbachia spread dynamics in stochastic environments.

    PubMed

    Hu, Linchao; Huang, Mugen; Tang, Moxun; Yu, Jianshe; Zheng, Bo

    2015-12-01

    Dengue fever is a mosquito-borne viral disease with 100 million people infected annually. A novel strategy for dengue control uses the bacterium Wolbachia to invade dengue vector Aedes mosquitoes. As the impact of environmental heterogeneity on Wolbachia spread dynamics in natural areas has been rarely quantified, we develop a model of differential equations for which the environmental conditions switch randomly between two regimes. We find some striking phenomena that random regime transitions could drive Wolbachia to extinction from certain initial states confirmed Wolbachia fixation in homogeneous environments, and mosquito releasing facilitates Wolbachia invasion more effectively when the regimes transit frequently. By superimposing the phase spaces of the ODE systems defined in each regime, we identify the threshold curves below which Wolbachia invades the whole population, which extends the theory of threshold infection frequency to stochastic environments. PMID:26428255

  18. Potential corridors and barriers for plague spread in central Asia

    PubMed Central

    2013-01-01

    Background Plague (Yersinia pestis infection) is a vector-borne disease which caused millions of human deaths in the Middle Ages. The hosts of plague are mostly rodents, and the disease is spread by the fleas that feed on them. Currently, the disease still circulates amongst sylvatic rodent populations all over the world, including great gerbil (Rhombomys opimus) populations in Central Asia. Great gerbils are social desert rodents that live in family groups in burrows, which are visible on satellite images. In great gerbil populations an abundance threshold exists, above which plague can spread causing epizootics. The spatial distribution of the host species is thought to influence the plague dynamics, such as the direction of plague spread, however no detailed analysis exists on the possible functional or structural corridors and barriers that are present in this population and landscape. This study aims to fill that gap. Methods Three 20 by 20 km areas with known great gerbil burrow distributions were used to analyse the spatial distribution of the burrows. Object-based image analysis was used to map the landscape at several scales, and was linked to the burrow maps. A novel object-based method was developed – the mean neighbour absolute burrow density difference (MNABDD) – to identify the optimal scale and evaluate the efficacy of using landscape objects as opposed to square cells. Multiple regression using raster maps was used to identify the landscape-ecological variables that explain burrow density best. Functional corridors and barriers were mapped using burrow density thresholds. Cumulative resistance of the burrow distribution to potential disease spread was evaluated using cost distance analysis. A 46-year plague surveillance dataset was used to evaluate whether plague spread was radially symmetric. Results The burrow distribution was found to be non-random and negatively correlated with Greenness, especially in the floodplain areas. Corridors and barriers showed a mostly NWSE alignment, suggesting easier spreading along this axis. This was confirmed by the analysis of the plague data. Conclusions Plague spread had a predominantly NWSE direction, which is likely due to the NWSE alignment of corridors and barriers in the burrow distribution and the landscape. This finding may improve predictions of plague in the future and emphasizes the importance of including landscape analysis in wildlife disease studies. PMID:24171709

  19. A Metric of Influential Spreading during Contagion Dynamics through the Air Transportation Network

    E-print Network

    Nicolaides, Christos

    The spread of infectious diseases at the global scale is mediated by long-range human travel. Our ability to predict the impact of an outbreak on human health requires understanding the spatiotemporal signature of early-time ...

  20. The Impact of Random Screening and Contact Tracing in Reducing the Spread of HIV

    E-print Network

    Hyman, James "Mac"

    on the spread of HIV and other sexually transmitted diseases by reducing the uncertainty in assessing the impact of the most e#11;ective methods used for controlling treatable sexually transmitted diseases, it is still in an initial highly infectious stage or in the late stages of the disease. In this model contact tracing

  1. Epidemic spread in coupled populations with seasonally varying migration rates

    NASA Astrophysics Data System (ADS)

    Muzyczyn, Adam; Shaw, Leah B.

    2009-03-01

    The H5N1 strain of avian influenza has spread worldwide, and this spread may be due to seasonal migration of birds and mixing of birds from different regions in the wintering grounds. We studied a multipatch model for avian influenza with seasonally varying migration rates. The bird population was divided into two spatially distinct patches, or subpopulations. Within each patch, the disease followed the SIR (susceptible-infected-recovered) model for epidemic spread. Migration rates were varied periodically, with a net flux toward the breeding grounds during the spring and towards the wintering grounds during the fall. The case of two symmetric patches reduced to single-patch SIR dynamics. However, asymmetry in the birth and contact rates in the breeding grounds and wintering grounds led to bifurcations to longer period orbits and chaotic dynamics. We studied the bifurcation structure of the model and the phase relationships between outbreaks in the two patches.

  2. Epidemic cholera in Latin America: spread and routes of transmission.

    PubMed

    Guthmann, J P

    1995-12-01

    In the most recent epidemic of cholera in Latin America, nearly a million cases were reported and almost 9000 people died between January 1991 and December 1993. The epidemic spread rapidly from country to country, affecting in three years all the countries of Latin America except Uruguay and the Caribbean. Case-control studies carried out in Peru showed a significant association between drinking water and risk of disease. Cholera was associated with the consumption of unwashed fruit and vegetables, with eating food from street vendors and with contaminated crabmeat transported in travellers' luggage. This article documents the spread of the epidemic and its routes of transmission and discusses whether the introduction of the epidemic to Peru and its subsequent spread throughout the continent could have been prevented. PMID:8544225

  3. Hydroclimatological And Anthropogenic Drivers For Cholera Spreading

    NASA Astrophysics Data System (ADS)

    Righetto, Lorenzo; Bertuzzo, Enrico; Mari, Lorenzo; Casagrandi, Renato; Gatto, Marino; Rinaldo, Andrea

    2010-05-01

    The nature of waterborne diseases, among which cholera has a prominent importance, calls for a better understanding of the link between epidemic spreading, water and climate. To this end, we have developed a framework which involves a network-based description of a river system, connected with local communities which act as nodes of the network. This has allowed us to produce consistent simulations of real case studies. More recent investigations comprise the evaluation of the spreading velocity of an epidemic wave by means of a reaction-diffusion modeling approach. In particular, we have found that both transport processes and epidemiological quantities, such as the basic reproduction number, have a crucial effect in controlling the spreading of the epidemics. We first developed a description of bacterial movement along the network driven by advection and diffusion; afterward, we have included the movement of human populations. This latter model allowed us to establish the conditions that can trigger epidemic waves that start from the coastal region, where bacteria are autochthonous, and travel inland. In particular, our findings suggest that even relatively low values of human diffusion can have the epidemic propagate upstream. The interaction between climate, hydrology and epidemic events is still much debated, since no clear correlation between climatologic and epidemiological phenomena has emerged so far. However, a spatial assessment of hydrological and epidemiological mechanisms could be crucial to understand the evolution of cholera outbreaks. In particular, a hotly debated topic is the understanding of the mechanisms that can generate patterns of cholera incidence that exhibit an intra-annual double peak, as frequently observed in endemic region such as Bangladesh. One of the possible explanations proposed in the literature is that spring droughts cause bacteria concentration in water to rise dramatically, triggering the first peak. On the other hand similar mechanisms can occur during flood recessions in autumn together with major water sanitation system failures and higher population density. We show here the results of an ecohydrological model that couples the dynamics of the disease to a description of both the local water reservoir and of the local river section. The goal of this modeling exercise is to reproduce and understand the mechanisms behind intra-annual cholera incidence dynamics driven by hydrologic variability.

  4. Spreading of a granular droplet.

    SciTech Connect

    Sanchez, I.; Raynaud, F.; Lanuza, J.; Andreotti, B.; Clement, E.; Aranson, I. S.; Materials Science Division; Univ. Simon; CNRS-ESPCI-Univ.

    2007-01-01

    The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the granular droplet) and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

  5. Is Vector Control Sufficient to Limit Pathogen Spread in Vineyards?

    PubMed

    Daugherty, M P; O'Neill, S; Byrne, F; Zeilinger, A

    2015-06-01

    Vector control is widely viewed as an integral part of disease management. Yet epidemiological theory suggests that the effectiveness of control programs at limiting pathogen spread depends on a variety of intrinsic and extrinsic aspects of a pathosystem. Moreover, control programs rarely evaluate whether reductions in vector density or activity translate into reduced disease prevalence. In areas of California invaded by the glassy-winged sharpshooter (Homalodisca vitripennis Germar), Pierce's disease management relies heavily on chemical control of this vector, primarily via systemic conventional insecticides (i.e., imidacloprid). But, data are lacking that attribute reduced vector pressure and pathogen spread to sharpshooter control. We surveyed 34 vineyards over successive years to assess the epidemiological value of within-vineyard chemical control. The results showed that imidacloprid reduced vector pressure without clear nontarget effects or secondary pest outbreaks. Effects on disease prevalence were more nuanced. Treatment history over the preceding 5?yr affected disease prevalence, with significantly more diseased vines in untreated compared with regularly or intermittently treated vineyards. Yet, the change in disease prevalence between years was low, with no significant effects of insecticide treatment or vector abundance. Collectively, the results suggest that within-vineyard applications of imidacloprid can reduce pathogen spread, but with benefits that may take multiple seasons to become apparent. The relatively modest effect of vector control on disease prevalence in this system may be attributable in part to the currently low regional sharpshooter population densities stemming from area-wide control, without which the need for within-vineyard vector control would be more pronounced. PMID:26313985

  6. Slip of Spreading Viscoplastic Droplets.

    PubMed

    Jalaal, Maziyar; Balmforth, Neil J; Stoeber, Boris

    2015-11-10

    The spreading of axisymmetric viscoplastic droplets extruded slowly on glass surfaces is studied experimentally using shadowgraphy and swept-field confocal microscopy. The microscopy furnishes vertical profiles of the radial velocity using particle image velocimetry (PIV) with neutrally buoyant tracers seeded in the fluid. Experiments were conducted for two complex fluids: aqueous solutions of Carbopol and xanthan gum. On untreated glass surfaces, PIV demonstrates that both fluids experience a significant amount of effective slip. The experiments were repeated on glass that had been treated to feature positive surface charges, thereby promoting adhesion between the negatively charged polymeric constituents of the fluids and the glass surface. The Carbopol and xanthan gum droplets spread more slowly on the treated surface and to a smaller radial distance. PIV demonstrated that this reduced spreading was associated with a substantial reduction in slip. For Carbopol, the effective slip could be eliminated entirely to within the precision of the PIV measurements; the reduction in slip was less effective for xanthan gum, with a weak slip velocity remaining noticeable. PMID:26418827

  7. On the Spatial Spread of Rabies among Foxes

    NASA Astrophysics Data System (ADS)

    Murray, J. D.; Stanley, E. A.; Brown, D. L.

    1986-11-01

    We present a simple model for the spatial spread of rabies among foxes and use it to quantify its progress in England if rabies were introduced. The model is based on the known ecology of fox behaviour and on the assumption that the main vector for the spread of the disease is the rabid fox. Known data and facts are used to determine real parameter values involved in the model. We calculate the speed of propagation of the epizootic front, the threshold for the existence of an epidemic, the period and distance apart of the subsequent cyclical epidemics which follow the main front, and finally we quantify a means for control of the spatial spread of the disease. By way of illustration we use the model to determine the progress of rabies up through the southern part of England if it were introduced near Southampton. Estimates for the current fox density in England were used in the simulations. These suggest that the disease would reach Manchester within about 3.5 years, moving at speeds as high as 100 km per year in the central region. The model further indicates that although it might seem that the disease had disappeared after the wave had passed it would reappear in the south of England after just over 6 years and at periodic times after that. We consider the possibility of stopping the spread of the disease by creating a rabies `break' ahead of the front through vaccination to reduce the population to a level below the threshold for an epidemic to exist. Based on parameter values relevant to England, we estimate its minimum width to be about 15 km. The model suggests that vaccination has considerable advantages over severe culling.

  8. IMPROVING WATERBORNE DISEASE SURVEILLANCE

    EPA Science Inventory

    Public health surveillance has played a key role in controlling the spread of communicable disease and identifying the need for specific publich health practices, such as the filteration and chlorination of drinking water supplies. However, the characteristics of waterborne ou...

  9. Reproductive Diseases in Cattle 

    E-print Network

    Sprott, L. R.; Field, Bob

    1998-12-03

    in Cattle State of Samples gestation needed for Diseases Organism How spread at abortion diagnosis Vaccination Remarks Brucellosis Bacterial Aborted fetuses, 6-9 months Blood sample Live vaccine in Cull infected animals. Do (Brucella abortus) fetal membranes...

  10. Fifth Disease (Erythema Infectiosum)

    MedlinePLUS

    ... Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family Life First Aid & Safety Doctors & ... rash spreads and red blotches (usually lighter in color) extend down to the trunk, arms, and legs. ...

  11. Assessing the role of spatial correlations during collective cell spreading

    NASA Astrophysics Data System (ADS)

    Treloar, Katrina K.; Simpson, Matthew J.; Binder, Benjamin J.; McElwain, D. L. Sean; Baker, Ruth E.

    2014-07-01

    Spreading cell fronts are essential features of development, repair and disease processes. Many mathematical models used to describe the motion of cell fronts, such as Fisher's equation, invoke a mean-field assumption which implies that there is no spatial structure, such as cell clustering, present. Here, we examine the presence of spatial structure using a combination of in vitro circular barrier assays, discrete random walk simulations and pair correlation functions. In particular, we analyse discrete simulation data using pair correlation functions to show that spatial structure can form in a spreading population of cells either through sufficiently strong cell-to-cell adhesion or sufficiently rapid cell proliferation. We analyse images from a circular barrier assay describing the spreading of a population of MM127 melanoma cells using the same pair correlation functions. Our results indicate that the spreading melanoma cell populations remain very close to spatially uniform, suggesting that the strength of cell-to-cell adhesion and the rate of cell proliferation are both sufficiently small so as not to induce any spatial patterning in the spreading populations.

  12. Antimalarial drug resistance: a review of the biology and strategies to delay emergence and spread

    PubMed Central

    Klein, E.Y.

    2013-01-01

    The emergence of resistance to former first-line antimalarial drugs has been an unmitigated disaster. In recent years, artemisinin class drugs have become standard and they are considered an essential tool for helping to eradicate the disease. However, their ability to reduce morbidity and mortality and to slow transmission requires the maintenance of effectiveness. Recently, an artemisinin delayed-clearance phenotype was described. This is believed to be the precursor to resistance and threatens local elimination and global eradication plans. Understanding how resistance emerges and spreads is important for developing strategies to contain its spread. Resistance is the result of two processes: (i) drug selection of resistant parasites; and (ii) the spread of resistance. In this review, we examine the factors that lead to both drug selection and the spread of resistance. We then examine strategies for controlling the spread of resistance, pointing out the complexities and deficiencies in predicting how resistance will spread. PMID:23394809

  13. [Bluetongue disease reaches Switzerland].

    PubMed

    Hofmann, M; Griot, C; Chaignat, V; Perler, L; Thür, B

    2008-02-01

    Since 2006 bluetongue disease is rapidly spreading across Europe and reached Switzerland in October 2007. In the present article a short overview about the disease and the virus is given, and the first three clinical bluetongue disease cases in cattle, and the respective laboratory findings are presented. PMID:18369049

  14. Sea-Floor Spreading and Transform Faults

    ERIC Educational Resources Information Center

    Armstrong, Ronald E.; And Others

    1978-01-01

    Presents the Crustal Evolution Education Project (CEEP) instructional module on Sea-Floor Spreading and Transform Faults. The module includes activities and materials required, procedures, summary questions, and extension ideas for teaching Sea-Floor Spreading. (SL)

  15. Dynamics of information spread on networks

    E-print Network

    Lerman, Kristina

    popular trends #12;USC Information Sciences Institute Comparative empirical analysis Digg · VotingDynamics of information spread on networks Kristina Lerman USC Information Sciences Institute #12;USC Information Sciences Institute Information spread in online social networks Diffusion

  16. Cell mediated innate responses of cattle and swine are diverse during foot-and-mouth disease virus (FMDV) infection: A unique landscape of innate immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogens in general and pathogenic viruses in particular have evolved a myriad of mechanisms to escape the immune response of mammalian species. Viruses that cause acute disease and are rapidly cleared tend to bear characteristics that make them very contagious, as survival does not derive from chr...

  17. An adenovirus vectored mucosal adjuvant augments protection of mice immunized intranasally with an adenovirus-vectored foot-and-mouth disease virus subunit vaccine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen that causes severe morbidity and economic losses to the livestock industry in many countries. The oral and respiratory mucosae are the main ports of entry of FMDV, so the stimulation of local immunity in these tissues may help preve...

  18. nem_spread Ver. 5.10

    Energy Science and Technology Software Center (ESTSC)

    2009-06-08

    Nem_spread reads it's input command file (default name nem_spread.inp), takes the named ExodusII geometry definition and spreads out the geometry (and optionally results) contained in that file out to a parallel disk system. The decomposition is taken from a scalar Nemesis load balance file generated by the companion utility nem_slice.

  19. Cortical spreading depression: An enigma

    NASA Astrophysics Data System (ADS)

    Miura, R. M.; Huang, H.; Wylie, J. J.

    2007-08-01

    The brain is a complex organ with active components composed largely of neurons, glial cells, and blood vessels. There exists an enormous experimental and theoretical literature on the mechanisms involved in the functioning of the brain, but we still do not have a good understanding of how it works on a gross mechanistic level. In general, the brain maintains a homeostatic state with relatively small ion concentration changes, the major ions being sodium, potassium, and chloride. Calcium ions are present in smaller quantities but still play an important role in many phenomena. Cortical spreading depression (CSD for short) was discovered over 60 years ago by A.A.P. Leão, a Brazilian physiologist doing his doctoral research on epilepsy at Harvard University, “Spreading depression of activity in the cerebral cortex," J. Neurophysiol., 7 (1944), pp. 359-390. Cortical spreading depression is characterized by massive changes in ionic concentrations and slow nonlinear chemical waves, with speeds on the order of mm/min, in the cortex of different brain structures in various experimental animals. In humans, CSD is associated with migraine with aura, where a light scintillation in the visual field propagates, then disappears, and is followed by a sustained headache. To date, CSD remains an enigma, and further detailed experimental and theoretical investigations are needed to develop a comprehensive picture of the diverse mechanisms involved in producing CSD. A number of mechanisms have been hypothesized to be important for CSD wave propagation. In this paper, we briefly describe several characteristics of CSD wave propagation, and examine some of the mechanisms that are believed to be important, including ion diffusion, membrane ionic currents, osmotic effects, spatial buffering, neurotransmitter substances, gap junctions, metabolic pumps, and synaptic connections. Continuum models of CSD, consisting of coupled nonlinear diffusion equations for the ion concentrations, and a discrete lattice-Boltzmann method approach will be described. Also, we will describe some open problems and remaining challenges.

  20. Hybrid spread spectrum radio system

    DOEpatents

    Smith, Stephen F. (London, TN); Dress, William B. (Camas, WA)

    2010-02-02

    Systems and methods are described for hybrid spread spectrum radio systems. A method includes modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control an amplification circuit that provides a gain to the signal. Another method includes: modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control a fast hopping frequency synthesizer; and fast frequency hopping the signal with the fast hopping frequency synthesizer, wherein multiple frequency hops occur within a single data-bit time.

  1. EDHF: spreading the influence of the endothelium

    PubMed Central

    Garland, Christopher J; Hiley, C Robin; Dora, Kim A

    2011-01-01

    Our view of the endothelium was transformed around 30 years ago, from one of an inert barrier to that of a key endocrine organ central to cardiovascular function. This dramatic change followed the discoveries that endothelial cells (ECs) elaborate the vasodilators prostacyclin and nitric oxide. The key to these discoveries was the use of the quintessentially pharmacological technique of bioassay. Bioassay also revealed endothelium-derived hyperpolarizing factor (EDHF), particularly important in small arteries and influencing blood pressure and flow distribution. The basic idea of EDHF as a diffusible factor causing smooth muscle hyperpolarization (and thus vasodilatation) has evolved into one of a complex pathway activated by endothelial Ca2+ opening two Ca2+-sensitive K+-channels, KCa2.3 and KCa3.1. Combined application of apamin and charybdotoxin blocked EDHF responses, revealing the critical role of these channels as iberiotoxin was unable to substitute for charybdotoxin. We showed these channels are arranged in endothelial microdomains, particularly within projections towards the adjacent smooth muscle, and close to interendothelial gap junctions. Activation of KCa channels hyperpolarizes ECs, and K+ efflux through them can act as a diffusible ‘EDHF’ stimulating Na+/K+-ATPase and inwardly rectifying K-channels. In parallel, hyperpolarizing current can spread from the endothelium to the smooth muscle through myoendothelial gap junctions upon endothelial projections. The resulting radial hyperpolarization mobilized by EDHF is complemented by spread of hyperpolarization along arteries and arterioles, effecting distant dilatation dependent on the endothelium. So the complexity of the endothelium still continues to amaze and, as knowledge evolves, provides considerable potential for novel approaches to modulate blood pressure. LINKED ARTICLES This article is part of a themed issue on Vascular Endothelium in Health and Disease. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.164.issue-3 PMID:21133895

  2. Age, spreading rates, and spreading asymmetry of the world's ocean crust

    E-print Network

    Müller, Dietmar

    are determined by linear interpolation between adjacent seafloor isochrons in the direction of spreading. Ages; seafloor spreading. Index Terms: 3040 Marine Geology and Geophysics: Plate tectonics (8150, 8155, 8157Age, spreading rates, and spreading asymmetry of the world's ocean crust R. Dietmar Mu

  3. 9 CFR 319.762 - Ham spread, tongue spread, and similar products.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND CERTIFICATION DEFINITIONS AND STANDARDS OF IDENTITY OR COMPOSITION Meat Salads and Meat Spreads § 319.762 Ham spread, tongue spread, and similar products. “Ham Spread,”...

  4. Tan F. Wong: Spread Spectrum & CDMA CHAPTER 0. OVERVIEW 0.1 What is spread spectrum?

    E-print Network

    Wong, Tan F.

    Tan F. Wong: Spread Spectrum & CDMA CHAPTER 0. OVERVIEW Chapter 0 Overview 0.1 What is spread spectrum? Spread spectrum: A modulation technique that produces a spectrum for the transmitted signal much to a spread spectrum modulation. BPSK, QPSK, QAM, and MSK are common examples of narrowband modulation

  5. Modeling the geographic spread of rabies in China.

    PubMed

    Chen, Jing; Zou, Lan; Jin, Zhen; Ruan, Shigui

    2015-05-01

    In order to investigate how the movement of dogs affects the geographically inter-provincial spread of rabies in Mainland China, we propose a multi-patch model to describe the transmission dynamics of rabies between dogs and humans, in which each province is regarded as a patch. In each patch the submodel consists of susceptible, exposed, infectious, and vaccinated subpopulations of both dogs and humans and describes the spread of rabies among dogs and from infectious dogs to humans. The existence of the disease-free equilibrium is discussed, the basic reproduction number is calculated, and the effect of moving rates of dogs between patches on the basic reproduction number is studied. To investigate the rabies virus clades lineages, the two-patch submodel is used to simulate the human rabies data from Guizhou and Guangxi, Hebei and Fujian, and Sichuan and Shaanxi, respectively. It is found that the basic reproduction number of the two-patch model could be larger than one even if the isolated basic reproduction number of each patch is less than one. This indicates that the immigration of dogs may make the disease endemic even if the disease dies out in each isolated patch when there is no immigration. In order to reduce and prevent geographical spread of rabies in China, our results suggest that the management of dog markets and trades needs to be regulated, and transportation of dogs has to be better monitored and under constant surveillance. PMID:26020234

  6. A combination of improved differential and global RNA-seq reveals pervasive transcription initiation and events in all stages of the life-cycle of functional RNAs in Propionibacterium acnes, a major contributor to wide-spread human disease

    PubMed Central

    2013-01-01

    Background Sequencing of the genome of Propionibacterium acnes produced a catalogue of genes many of which enable this organism to colonise skin and survive exposure to the elements. Despite this platform, there was little understanding of the gene regulation that gives rise to an organism that has a major impact on human health and wellbeing and causes infections beyond the skin. To address this situation, we have undertaken a genome–wide study of gene regulation using a combination of improved differential and global RNA-sequencing and an analytical approach that takes into account the inherent noise within the data. Results We have produced nucleotide-resolution transcriptome maps that identify and differentiate sites of transcription initiation from sites of stable RNA processing and mRNA cleavage. Moreover, analysis of these maps provides strong evidence for ‘pervasive’ transcription and shows that contrary to initial indications it is not biased towards the production of antisense RNAs. In addition, the maps reveal an extensive array of riboswitches, leaderless mRNAs and small non-protein-coding RNAs alongside vegetative promoters and post-transcriptional events, which includes unusual tRNA processing. The identification of such features will inform models of complex gene regulation, as illustrated here for ribonucleotide reductases and a potential quorum-sensing, two-component system. Conclusions The approach described here, which is transferable to any bacterial species, has produced a step increase in whole-cell knowledge of gene regulation in P. acnes. Continued expansion of our maps to include transcription associated with different growth conditions and genetic backgrounds will provide a new platform from which to computationally model the gene expression that determines the physiology of P. acnes and its role in human disease. PMID:24034785

  7. Clinico-pathological significance of extra-nodal spread in special types of breast cancer

    PubMed Central

    Kaygusuz, Ecmel Isik; Cetiner, Handan; Yavuz, Hulya

    2014-01-01

    Objective To investigate the significance of extra-nodal spread in special histological sub-types of breast cancer and the relationship of such spread with prognostic parameters. Methods A total of 303 breast cancer cases were classified according to tumor type, and each tumor group was subdivided according to age, tumor diameter, lymph node metastasis, extra-nodal spread, vein invasion in the adjacent soft tissue, distant metastasis, and immunohistochemical characteristics [estrogen receptor (ER), progesterone receptor (PR) existence, p53, c-erbB-2, and proliferative rate (Ki-67)]. The 122 cases with extra-nodal spread were clinically followed up. Results An extra-nodal spread was observed in 40% (122 cases) of the 303 breast cancer cases. The spread most frequently presented in micro papillary carcinoma histological sub-type (40 cases, 75%), but least frequently presents in mucinous carcinoma (2 cases, 8%). Patients with extra-nodal spread had a high average number of metastatic lymph nodes (8.3) and a high distant metastasis rate (38 cases, 31%) compared with patients without extra-nodal spread. Conclusion The existence of extra-nodal spread in the examined breast cancer sub-types has predictive value in forecasting the number of metastatic lymph nodes and the disease prognosis. PMID:25009753

  8. Participatory Epidemiology of Ethnoveterinary Practices Fulani Pastoralists Used to Manage Contagious Bovine Pleuropneumonia and Other Cattle Ailments in Niger State, Nigeria

    PubMed Central

    Alhaji, N. B.; Babalobi, O. O.

    2015-01-01

    Ethnoveterinary practices are locally available and affordable to Fulani pastoralists in Niger State, Nigeria, to whom conventional veterinary services are often not readily available and are relatively expensive. This study was designed to identify and document medicinal plant and nonplant materials used by this group in the management of cattle diseases. Participatory rural appraisal tools of checklist, semistructured interview, probing, transect, and triangulations were used to assess Fulani pastoralists existing knowledge on traditional veterinary practices in nine pastoral communities spread across the state. Fifty medicinal materials and seven traditional preventive practices are in use against CBPP and other cattle disease conditions. Of these, 38 (76.0%) are medicinal plants and 12 (24.0%) are nonplant materials (edible earth materials and minerals). Family Fabaceae was most commonly mentioned while leaves were the most common parts used. Most of these materials are administered by drenching with few others mixed with feed. Proportions of plant parts used include leaves (47.4%), barks (31.6%), roots (10.6%), and 2.6% of each of rhizomes, fruits, seeds, and whole plants. Of recently used ingredients are kerosene and spent engine oil. Further research into the active ingredients of ethnoveterinary materials and dosages is necessary to guide their usage. PMID:26464953

  9. Participatory Epidemiology of Ethnoveterinary Practices Fulani Pastoralists Used to Manage Contagious Bovine Pleuropneumonia and Other Cattle Ailments in Niger State, Nigeria.

    PubMed

    Alhaji, N B; Babalobi, O O

    2015-01-01

    Ethnoveterinary practices are locally available and affordable to Fulani pastoralists in Niger State, Nigeria, to whom conventional veterinary services are often not readily available and are relatively expensive. This study was designed to identify and document medicinal plant and nonplant materials used by this group in the management of cattle diseases. Participatory rural appraisal tools of checklist, semistructured interview, probing, transect, and triangulations were used to assess Fulani pastoralists existing knowledge on traditional veterinary practices in nine pastoral communities spread across the state. Fifty medicinal materials and seven traditional preventive practices are in use against CBPP and other cattle disease conditions. Of these, 38 (76.0%) are medicinal plants and 12 (24.0%) are nonplant materials (edible earth materials and minerals). Family Fabaceae was most commonly mentioned while leaves were the most common parts used. Most of these materials are administered by drenching with few others mixed with feed. Proportions of plant parts used include leaves (47.4%), barks (31.6%), roots (10.6%), and 2.6% of each of rhizomes, fruits, seeds, and whole plants. Of recently used ingredients are kerosene and spent engine oil. Further research into the active ingredients of ethnoveterinary materials and dosages is necessary to guide their usage. PMID:26464953

  10. Spread F theories: A review

    NASA Astrophysics Data System (ADS)

    Ossakow, S. L.

    1981-01-01

    Our understanding of equatorial spread F (ESF) phenomena has increased dramatically over the past few years: notwithstanding the fact that it was discovered over four decades ago (BOOKER and WELLS, 1938) as diffuse echoes on ionograms. Much of this advancement in understanding comes from a combined theoretical and experimental approach to the problem. Advances in radar backscatter measurements, satellite and rocket in situ measurements, and theoretical and numerical simulation techniques have provided a clearer picture of the fundamental mechanisms causing ESF. The study of ESF phenomena has been both complicated and enriched by the fact that the attendant magnetic field aligned ionospheric irregularities span some 5-6 orders of magnitude in scale sizes. The present paper will deal with ESF theory and at that only those theories using plasma mechanisms as a basis. Experimental reviews of the subject can be found in other papers in this edition. An examination is made of the basic equatorial nighttime ionospheric F region geometry.

  11. SAW correlator spread spectrum receiver

    DOEpatents

    Brocato, Robert W

    2014-04-01

    A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n.times.m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

  12. Ethics and infectious disease.

    PubMed

    Selgelid, Michael J

    2005-06-01

    Bioethics apparently suffers from a misdistribution of research resources analogous to the '10/90' divide in medical research. Though infectious disease should be recognized as a topic of primary importance for bioethics, the general topic of infectious disease has received relatively little attention from the discipline of bioethics in comparison with things like abortion, euthanasia, genetics, cloning, stem cell research, and so on. The fact that the historical and potential future consequences of infectious diseases are almost unrivalled is one reason that the topic of infectious disease warrants more attention from bioethicists. The 'Black Death' eliminated one third of the European population during the 14th Century; the 1989 flu killed between 20 and 100 million people; and, in the 20th Century smallpox killed perhaps three times more people than all the wars of that period. In the contemporary world, epidemics (AIDS, multi-drug resistant turberculosis, and newly emerging infectious diseases such as SARS) continue to have dramatic consequences. A second reason why the topic of infectious disease deserves further attention is that it raises difficult ethical questions of its own. While infected individuals can threaten the health of other individuals and society as a whole, for example, public health care measures such as surveillance, isolation, and quarantine can require the infringement of widely accepted basic human rights and liberties. An important and difficult ethical question asks how to strike a balance between the utilitarian aim of promoting public health, on the one hand, and libertarian aims of protecting privacy and freedom of movement, on the other, in contexts involving diseases that are--to varying degrees--contagious, deadly, or otherwise dangerous. Third, since their burden is most heavily shouldered by the poor (in developing countries), infectious diseases involve issues of justice--which should be a central concern of ethics. I conclude by providing sociological and historical explanations of why the topic of infectious disease has not already received more attention from bioethicists. PMID:16167406

  13. A Spread Willingness Computing-Based Information Dissemination Model

    PubMed Central

    Cui, Zhiming; Zhang, Shukui

    2014-01-01

    This paper constructs a kind of spread willingness computing based on information dissemination model for social network. The model takes into account the impact of node degree and dissemination mechanism, combined with the complex network theory and dynamics of infectious diseases, and further establishes the dynamical evolution equations. Equations characterize the evolutionary relationship between different types of nodes with time. The spread willingness computing contains three factors which have impact on user's spread behavior: strength of the relationship between the nodes, views identity, and frequency of contact. Simulation results show that different degrees of nodes show the same trend in the network, and even if the degree of node is very small, there is likelihood of a large area of information dissemination. The weaker the relationship between nodes, the higher probability of views selection and the higher the frequency of contact with information so that information spreads rapidly and leads to a wide range of dissemination. As the dissemination probability and immune probability change, the speed of information dissemination is also changing accordingly. The studies meet social networking features and can help to master the behavior of users and understand and analyze characteristics of information dissemination in social network. PMID:25110738

  14. Competing spreading processes on multiplex networks: Awareness and epidemics

    NASA Astrophysics Data System (ADS)

    Granell, Clara; Gómez, Sergio; Arenas, Alex

    2014-07-01

    Epidemiclike spreading processes on top of multilayered interconnected complex networks reveal a rich phase diagram of intertwined competition effects. A recent study by the authors [C. Granell et al., Phys. Rev. Lett. 111, 128701 (2013)., 10.1103/PhysRevLett.111.128701] presented an analysis of the interrelation between two processes accounting for the spreading of an epidemic, and the spreading of information awareness to prevent 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 completion 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 the two competing processes for a wide spectrum of parameters representing the interaction between them. We also analyze the consequences of a massive broadcast of awareness (mass media) on the final outcome of the epidemic incidence. Importantly enough, the mass media make the metacritical point disappear. The results reveal that the main finding, i.e., existence of a metacritical point, is rooted in the competition principle and holds for a large set of scenarios.

  15. Impacts of suppressing guide on information spreading

    E-print Network

    Xu, Jinghong; Ma, Baojun; Wu, Ye

    2015-01-01

    It is quite common that guides are introduced to suppress the information spreading in modern society for different purposes. In this paper, an agent-based model is established to quantitatively analyze the impacts of suppressing guides on information spreading. We find that the spreading threshold depends on the attractiveness of the information and the topology of the social network with no suppressing guides at all. Usually, one would expect that the existence of suppressing guides in the spreading procedure may result in less diffusion of information within the overall network. However, we find that sometimes the opposite is true: the manipulating nodes of suppressing guides may lead to more extensive information spreading when there are audiences with the reversal mind. These results can provide valuable theoretical references to public opinion guidance on various information, e.g., rumor or news spreading.

  16. Impacts of suppressing guide on information spreading

    NASA Astrophysics Data System (ADS)

    Xu, Jinghong; Zhang, Lin; Ma, Baojun; Wu, Ye

    2016-02-01

    It is quite common that guides are introduced to suppress the information spreading in modern society for different purposes. In this paper, an agent-based model is established to quantitatively analyze the impacts of suppressing guides on information spreading. We find that the spreading threshold depends on the attractiveness of the information and the topology of the social network with no suppressing guides at all. Usually, one would expect that the existence of suppressing guides in the spreading procedure may result in less diffusion of information within the overall network. However, we find that sometimes the opposite is true: the manipulating nodes of suppressing guides may lead to more extensive information spreading when there are audiences with the reversal mind. These results can provide valuable theoretical references to public opinion guidance on various information, e.g., rumor or news spreading.

  17. Targeted Restoration of the Intestinal Microbiota with a Simple, Defined Bacteriotherapy Resolves Relapsing Clostridium difficile Disease in Mice

    PubMed Central

    Lawley, Trevor D.; Stares, Mark D.; Connor, Thomas R.; Raisen, Claire; Goulding, David; Rad, Roland; Schreiber, Fernanda; Brandt, Cordelia; Deakin, Laura J.; Pickard, Derek J.; Duncan, Sylvia H.; Flint, Harry J.; Clark, Taane G.; Parkhill, Julian; Dougan, Gordon

    2012-01-01

    Relapsing C. difficile disease in humans is linked to a pathological imbalance within the intestinal microbiota, termed dysbiosis, which remains poorly understood. We show that mice infected with epidemic C. difficile (genotype 027/BI) develop highly contagious, chronic intestinal disease and persistent dysbiosis characterized by a distinct, simplified microbiota containing opportunistic pathogens and altered metabolite production. Chronic C. difficile 027/BI infection was refractory to vancomycin treatment leading to relapsing disease. In contrast, treatment of C. difficile 027/BI infected mice with feces from healthy mice rapidly restored a diverse, healthy microbiota and resolved C. difficile disease and contagiousness. We used this model to identify a simple mixture of six phylogenetically diverse intestinal bacteria, including novel species, which can re-establish a health-associated microbiota and clear C. difficile 027/BI infection from mice. Thus, targeting a dysbiotic microbiota with a defined mixture of phylogenetically diverse bacteria can trigger major shifts in the microbial community structure that displaces C. difficile and, as a result, resolves disease and contagiousness. Further, we demonstrate a rational approach to harness the therapeutic potential of health-associated microbial communities to treat C. difficile disease and potentially other forms of intestinal dysbiosis. PMID:23133377

  18. Targeted restoration of the intestinal microbiota with a simple, defined bacteriotherapy resolves relapsing Clostridium difficile disease in mice.

    PubMed

    Lawley, Trevor D; Clare, Simon; Walker, Alan W; Stares, Mark D; Connor, Thomas R; Raisen, Claire; Goulding, David; Rad, Roland; Schreiber, Fernanda; Brandt, Cordelia; Deakin, Laura J; Pickard, Derek J; Duncan, Sylvia H; Flint, Harry J; Clark, Taane G; Parkhill, Julian; Dougan, Gordon

    2012-01-01

    Relapsing C. difficile disease in humans is linked to a pathological imbalance within the intestinal microbiota, termed dysbiosis, which remains poorly understood. We show that mice infected with epidemic C. difficile (genotype 027/BI) develop highly contagious, chronic intestinal disease and persistent dysbiosis characterized by a distinct, simplified microbiota containing opportunistic pathogens and altered metabolite production. Chronic C. difficile 027/BI infection was refractory to vancomycin treatment leading to relapsing disease. In contrast, treatment of C. difficile 027/BI infected mice with feces from healthy mice rapidly restored a diverse, healthy microbiota and resolved C. difficile disease and contagiousness. We used this model to identify a simple mixture of six phylogenetically diverse intestinal bacteria, including novel species, which can re-establish a health-associated microbiota and clear C. difficile 027/BI infection from mice. Thus, targeting a dysbiotic microbiota with a defined mixture of phylogenetically diverse bacteria can trigger major shifts in the microbial community structure that displaces C. difficile and, as a result, resolves disease and contagiousness. Further, we demonstrate a rational approach to harness the therapeutic potential of health-associated microbial communities to treat C. difficile disease and potentially other forms of intestinal dysbiosis. PMID:23133377

  19. Spread and SpreadRecorder An Architecture for Data Distribution

    NASA Technical Reports Server (NTRS)

    Wright, Ted

    2006-01-01

    The Space Acceleration Measurement System (SAMS) project at the NASA Glenn Research Center (GRC) has been measuring the microgravity environment of the space shuttle, the International Space Station, MIR, sounding rockets, drop towers, and aircraft since 1991. The Principle Investigator Microgravity Services (PIMS) project at NASA GRC has been collecting, analyzing, reducing, and disseminating over 3 terabytes of collected SAMS and other microgravity sensor data to scientists so they can understand the disturbances that affect their microgravity science experiments. The years of experience with space flight data generation, telemetry, operations, analysis, and distribution give the SAMS/ PIMS team a unique perspective on space data systems. In 2005, the SAMS/PIMS team was asked to look into generalizing their data system and combining it with the nascent medical instrumentation data systems being proposed for ISS and beyond, specifically the Medical Computer Interface Adapter (MCIA) project. The SpreadRecorder software is a prototype system developed by SAMS/PIMS to explore ways of meeting the needs of both the medical and microgravity measurement communities. It is hoped that the system is general enough to be used for many other purposes.

  20. Trigeminal perineural spread of head and neck tumors.

    PubMed

    Bartiromo, F; Cirillo, L; Caranci, F; Elefante, A; D'Amico, A; Tortora, F; Brunetti, A; Cirillo, S

    2007-02-28

    Perineural tumor spread (PNS) of head and neck malignancies is a well-known form of metastatic disease in which a lesion can migrate away from the primary site along the endoneurium or perineurium. MR imaging is considered the primary method for evaluating patients with symptoms related to the trigeminal nerve in most clinical settings. Both CT and MR imaging can detect perineural spread, but MRI is the modality of choice because of its capability to detect direct signs (nerve enlargement and enhancement) and indirect signs (neuropathic muscular atrophy, obliteration of fat planes). In addition, MRI is more sensitive because of its superior soft-tissue contrast, its multiplanar capability and decreased artifacts from dental hardware. Fat suppression images after contrast injection are mandatory to better detect nerve enhancement. CT is useful in detecting foraminal enlargement or more destructive bone patterns. Nerve function can be perserved until later in the course of the disease: patients with perineural spread demonstrated at radiologic or pathologic examination may have normal or nonspecific nerve function at clinical examination (patients are misdiagnosed with Bell's palsy or trigeminal neuralgia). Hence MRI assessment of perineural tumor location and extension is important. PMID:24299600