Science.gov

Sample records for contagious disease spread

  1. Early detection of contagious diseases

    DOEpatents

    Colston, Jr., Billy W.; Milanovich, Fred P.; Estacio, Pedro; Chang, John

    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. Mycoplasmal conjunctivitis in wild songbirds: the spread of a new contagious disease in a mobile host population.

    PubMed Central

    Fischer, J. R.; Stallknecht, D. E.; Luttrell, P.; Dhondt, A. A.; Converse, K. A.

    1997-01-01

    A new mycoplasmal conjunctivitis was first reported in wild house finches (Carpodacus mexicanus) in early 1994. The causative agent was identified as Mycoplasma gallisepticum (MG), a nonzoonotic pathogen of poultry that had not been associated with disease in wild songbirds. Since the initial observations of affected house finches in the mid-Atlantic region, the disease has become widespread and has been reported throughout the eastern United States and Canada. By late 1995, mycoplasmal conjunctivitis had spread to an additional species, the American goldfinch (Carduelis tristis). This new disease exemplifies the rapid spread of a pathogen following introduction into a mobile wildlife population and provides lessons that may apply to emerging human diseases. PMID:9126448

  3. The role of contagious disease in udder health

    PubMed Central

    Barkema, H. W.; Green, M. J.; Bradley, A. J.; Zadoks, R. N.

    2009-01-01

    Contagious diseases are a threat to animal health and productivity, both nationally and at the farm level. This makes implementation of biosecurity measures to prevent their introduction and spread within countries and farms a necessity. Mastitis is the most common and costly contagious disease affecting dairy farms in the western world. The major mastitis pathogens are endemic in most countries, and biosecurity measures to prevent introduction and transmission must therefore be implemented at farm level. The 40-yr-old mastitis control plan remains a solid foundation to prevent the spread of contagious intramammary infections. Contagious diseases that do not affect the mammary gland directly may have an indirect effect on mastitis. This is true for list A diseases such as foot and mouth disease, for which biosecurity measures may need to be taken at national level, and for other infections with nonmastitis pathogens such as bovine viral diarrhea virus and Mycobacterium avium ssp. paratuberculosis. Maintaining a closed herd decreases the risk of introduction of pathogens that affect udder health directly or indirectly. If animals are purchased, their udder health history should be evaluated and they should be examined and tested for contagious diseases. Transmission of infections by and to humans and nonbovine animals may occur. Contact with visitors and nonbovine animals should therefore be minimized. Because of globalization and heightened consumer awareness, the importance of biosecurity now supersedes individual farms, and increased pressure to control transmission of contagious diseases can be expected at industry or government levels in western countries and elsewhere. PMID:19762787

  4. How contagious is Dutch disease

    SciTech Connect

    Laney, L.O.

    1982-03-01

    Into the vernacular of economists has come the term Dutch Disease from the Netherland's experience as a net energy exporter. After outlining characterisics of the affliction and the ways in which it can be manifested, this article looks at the economies of United Kingdom, Norway, and Mexico. While the stage of economic development, the structure of the balance of payments, and the exchange-rate regime are at least somewhat different for each, all have economies that are feeling the impact of the energy sector. Common factors are a higher value for the exchange rate than would otherwise be the case and a squeeze on nonenergy sectors of the economy. 4 figures.

  5. 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…

  6. Discrete dynamics of contagious social diseases: Example of obesity.

    PubMed

    Demongeot, J; Hansen, O; Taramasco, C

    2016-01-01

    Modeling contagious diseases needs to incorporate information about social networks through which the disease spreads as well as data about demographic and genetic changes in the susceptible population. In this paper, we propose a theoretical framework (conceptualization and formalization) which seeks to model obesity as a process of transformation of one's own body determined by individual (physical and psychological), inter-individual (relational, i.e., relative to the relationship between the individual and others) and socio-cultural (environmental, i.e., relative to the relationship between the individual and his milieu) factors. Individual and inter-individual factors are tied to each other in a socio-cultural context whose impact is notably related to the visibility of anybody being exposed on the public stage in a non-contingent way. The question we are dealing with in this article is whether such kind of social diseases, i.e., depending upon socio-environmental exposure, can be considered as "contagious". In other words, can obesity be propagated from individual to individual or from environmental sources throughout an entire population?

  7. Contagious ovine digital dermatitis: an emerging disease.

    PubMed

    Duncan, J S; Angell, J W; Carter, S D; Evans, N J; Sullivan, L E; Grove-White, D H

    2014-09-01

    The novel sheep disease, contagious ovine digital dermatitis (CODD) was first described in the UK in 1997. The disease is characterised by severe lameness associated with initial inflammation at the coronary band, followed by progressive separation of the hoof capsule from the underlying tissue. On microbiological examination, treponeme bacteria have been frequently isolated from cases of CODD, including treponemes phylogenetically identical to those associated with bovine digital dermatitis (BDD). Dichelobacter nodosus and Fusobacterium necrophorum have also been isolated from CODD lesions although their role in the pathogenesis remains uncertain. While epidemiological data indicate that the prevalence of CODD is increasing in the UK, the routes of transmission and associated risk factors have not been clearly elucidated. Evidenced-based treatment trials indicate that parenteral administration of long-acting amoxicillin is an efficacious treatment for CODD, while anecdotal evidence suggests other antibiotics, given locally and/or parenterally, may also be beneficial. Further microbiological and epidemiological research is urgently required to develop sustainable control strategies, including the development of vaccines and appropriate biosecurity and farm management protocols. In this review current knowledge of the clinical, aetiological, and epidemiological aspects of CODD is assessed as well as approaches to its control.

  8. Discrete dynamics of contagious social diseases: Example of obesity

    PubMed Central

    Demongeot, J; Hansen, O; Taramasco, C

    2016-01-01

    Abstract Modeling contagious diseases needs to incorporate information about social networks through which the disease spreads as well as data about demographic and genetic changes in the susceptible population. In this paper, we propose a theoretical framework (conceptualization and formalization) which seeks to model obesity as a process of transformation of one's own body determined by individual (physical and psychological), inter-individual (relational, i.e., relative to the relationship between the individual and others) and socio-cultural (environmental, i.e., relative to the relationship between the individual and his milieu) factors. Individual and inter-individual factors are tied to each other in a socio-cultural context whose impact is notably related to the visibility of anybody being exposed on the public stage in a non-contingent way. The question we are dealing with in this article is whether such kind of social diseases, i.e., depending upon socio-environmental exposure, can be considered as “contagious”. In other words, can obesity be propagated from individual to individual or from environmental sources throughout an entire population? PMID:26375495

  9. 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…

  10. 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…

  11. 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…

  12. 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.

  13. The Application of Contagious Disease Epidemiological Models to Known Population Structure and Movement

    DTIC Science & Technology

    2016-03-01

    casualties that could result from the use of the contagious biological agents plague and smallpox against Allied forces. The current AMedP-8(C...military population, a series of model runs were conducted for smallpox and plague , while varying the number of initial infections and the...Factor Matrix No. of Primary Infections Disease Structure & Movement Location of Initial Infections* 1 Plague Single Population at Risk (PAR

  14. 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.…

  15. 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

  16. 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.

  17. The Use of Illegal Drugs and Infectious Contagious Diseases: Knowledge and Intervention among Dockworkers

    PubMed Central

    Cezar-Vaz, Marta Regina; Bonow, Clarice Alves; da Silva, Mara Regina Santos; de Farias, Francisca Lucélia Ribeiro; de Almeida, Marlise Capa Verde

    2016-01-01

    This study’s objective was to analyze the use of illegal drugs by dockworkers and provide risk communication regarding the use of illegal drugs and test for infectious contagious diseases among dockworkers. This cross-sectional study including an intervention addressed to 232 dockworkers, who were individually interviewed, as well as communication of risk with testing for infectious contagious diseases for 93 dockworkers from a city in the interior of Rio Grande do Sul, Brazil. Poisson regression analysis was used. Twenty-nine workers reported the use of illegal drugs. Poisson regression indicated that being a wharfage worker, smoker, having a high income, and heavier workload increases the prevalence of the use of illegal drugs. During risk communication, two workers were diagnosed with hepatitis B (2.2%), three (3.2%) with hepatitis C, two (2.2%) with syphilis. None of the workers, though, had HIV. This study provides evidence that can motivate further research on the topic and also lead to treatment of individuals to improve work safety, productivity, and the health of workers. PMID:26771625

  18. [Individual rights vs public health in the fight against contagious diseases: proposals to improve the current legal framework].

    PubMed

    Salamero Teixidó, Laura

    2016-11-01

    The public health protection constitutional mandate requires public powers to protect the population from contagious diseases. This requires a legal framework that both protects public health effectively and respects individual rights and freedoms that could be undermined by the public administrations. This article analyses, from a legal perspective, the current legal framework regulating the adoption of health measures to protect public health against contagious diseases. It argues that current regulations generate legal uncertainty on the basis of the wide range of discretionary powers they give to the public administration and the lack of provisions for limiting these powers. As a result, the guarantee mechanisms (primarily judicial consent) only weakly protect the rights and freedoms of the citizens affected by health measures. To conclude, the article proposes several amendments to improve public health regulations related to contagious diseases. The purpose is to render a legal framework that offers more legal certainty, in which it is possible to protect individual rights and freedoms when measures are adopted, without sacrificing the effective protection of public health.

  19. [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).

  20. 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

  1. [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.

  2. A Drug-Centric View of Drug Development: How Drugs Spread from Disease to Disease.

    PubMed

    Rodriguez-Esteban, Raul

    2016-04-01

    Drugs are often seen as ancillary to the purpose of fighting diseases. Here an alternative view is proposed in which they occupy a spearheading role. In this view, drugs are technologies with an inherent therapeutic potential. Once created, they can spread from disease to disease independently of the drug creator's original intentions. Through the analysis of extensive literature and clinical trial records, it can be observed that successful drugs follow a life cycle in which they are studied at an increasing rate, and for the treatment of an increasing number of diseases, leading to clinical advancement. Such initial growth, following a power law on average, has a degree of momentum, but eventually decelerates, leading to stagnation and decay. A network model can describe the propagation of drugs from disease to disease in which diseases communicate with each other by receiving and sending drugs. Within this model, some diseases appear more prone to influence other diseases than be influenced, and vice versa. Diseases can also be organized into a drug-centric disease taxonomy based on the drugs that each adopts. This taxonomy reflects not only biological similarities across diseases, but also the level of differentiation of existing therapies. In sum, this study shows that drugs can become contagious technologies playing a driving role in the fight against disease. By better understanding such dynamics, pharmaceutical developers may be able to manage drug projects more effectively.

  3. A Drug-Centric View of Drug Development: How Drugs Spread from Disease to Disease

    PubMed Central

    Rodriguez-Esteban, Raul

    2016-01-01

    Drugs are often seen as ancillary to the purpose of fighting diseases. Here an alternative view is proposed in which they occupy a spearheading role. In this view, drugs are technologies with an inherent therapeutic potential. Once created, they can spread from disease to disease independently of the drug creator’s original intentions. Through the analysis of extensive literature and clinical trial records, it can be observed that successful drugs follow a life cycle in which they are studied at an increasing rate, and for the treatment of an increasing number of diseases, leading to clinical advancement. Such initial growth, following a power law on average, has a degree of momentum, but eventually decelerates, leading to stagnation and decay. A network model can describe the propagation of drugs from disease to disease in which diseases communicate with each other by receiving and sending drugs. Within this model, some diseases appear more prone to influence other diseases than be influenced, and vice versa. Diseases can also be organized into a drug-centric disease taxonomy based on the drugs that each adopts. This taxonomy reflects not only biological similarities across diseases, but also the level of differentiation of existing therapies. In sum, this study shows that drugs can become contagious technologies playing a driving role in the fight against disease. By better understanding such dynamics, pharmaceutical developers may be able to manage drug projects more effectively. PMID:27124390

  4. [Disease in the cloisters: requests to leave Convento da Ajuda, Rio de Janeiro, for the treatment of contagious diseases, c.1750-1780].

    PubMed

    Martins, William de Souza

    2016-01-01

    This article discusses the requests submitted by nuns from Convento da Ajuda (Ajuda Convent) to leave their life of enclosure to receive treatment for contagious diseases. Disease was one of the few cases in which nuns were granted permission to leave. The female orders were strictly cloistered in order to preserve their purity as virgins consecrated to Christ. Extant documents detail the causes of the diseases, the ways they were transmitted, and the treatments used to fight them. These processes shed light on the procedures adopted outside the cloisters so that the nuns did not jeopardize their reclusion and honor when they went to distant places in search of treatment.

  5. Simulation Study on Effects of Order and Step Size of Runge-Kutta Methods that Solve Contagious Disease and Tumor Models.

    PubMed

    Z, Wang; Q, Wang; Dj, Klinke

    2016-09-01

    Biological processes such as contagious disease spread patterns and tumor growth dynamics are modelled using a set of coupled differential equations. Experimental data is usually used to calibrate models so they can be used to make future predictions. In this study, numerical methods were implemented to approximate solutions to mathematical models that were not solvable analytically, such as a SARS model. More complex models such as a tumor growth model involve high-dimensional parameter spaces; efficient numerical simulation techniques were used to search for optimal or close-to-optimal parameter values in the equations. Runge-Kutta methods are a group of explicit and implicit numerical methods that effectively solve the ordinary differential equations in these models. Effects of the order and the step size of Runge-Kutta methods were studied in order to maximize the search accuracy and efficiency in parameter spaces of the models. Numerical simulation results showed that an order of four gave the best balance between truncation errors and the simulation speed for SIR, SARS, and tumormodels studied in the project. The optimal step size for differential equation solvers was found to be model-dependent.

  6. [Epidemiological examples of infectious disease spread].

    PubMed

    Schlüter, H; Kramer, M

    2001-08-01

    The globalisation of trade with animals and animal products and increase of travel transports are very important issues with respect to prevent and control animal diseases or epizootics respectively. The disease control concepts as a complex manner should be established on scientific basis and must be permanently evaluated and updated. Outbreak investigations in order to clarify the source of infection and/or the spread of animal diseases including zoonoses are important fields of activities of veterinary epidemiologists. The application of modern epidemiological methods is the precondition of a successful disease control. On selected examples of animal diseases, the use of these methods is demonstrated. It is urgently necessary to intensify the epidemiological work in applied research and practice.

  7. A deterministic model for highly contagious diseases: The case of varicella

    NASA Astrophysics Data System (ADS)

    Acedo, L.; Moraño, J.-A.; Santonja, F.-J.; Villanueva, R.-J.

    2016-05-01

    The classic nonlinear Kermack-McKendrick model based upon a system of differential equations has been widely applied to model the rise and fall of global pandemic and also seasonal epidemic by introducing a forced harmonic infectivity which would change throughout the year. These methods work well in their respective domains of applicability, and for certain diseases, but they fail when both seasonality and high infectivity are combined. In this paper we consider a Susceptible-Infected-Recovered, or SIR, model with two latent states to model the propagation and evolutionary history of varicella in humans. We show that infectivity can be calculated from real data and we find a nonstandard seasonal variation that cannot be fitted with a single harmonic. Moreover, we show that infectivity for the present strains of the virus has raised following a sigmoid function in a period of several centuries. This could allow the design of vaccination strategies and the study of the epidemiology of varicella and herpes zoster.

  8. Pastoral care of patients with Ebola Virus Disease: A medical and canonical opinion about pastoral visits to patients with contagious and highly fatal diseases

    PubMed Central

    Hannan, Stephen E.; Nguyen, Benedict T.

    2015-01-01

    The Ebola Virus Disease is a contagious and highly fatal illness that up until recently had been geographically limited to remote areas of Africa. In 2014, Ebola patients have been transported to the United States for care or have been newly diagnosed in the United States. With the intensive medical care and isolation policies usually needed by these patients, we inquired whether pastoral care would be possible. Using clinical and canonical considerations, we analyzed the permissibility and logistical challenges pastoral care presents to the priests and lay ministers, as well as the healthcare system. We conclude that with the approval of local, state, and federal health officials, pastoral care, including provision of the sacraments, is possible. It would require proper training, proper equipment and policies, and a significant commitment of time. While the risk to the pastoral team is difficult to define, it seems low in an Ebola-capable medical system. These risks to priests and ministers seem reasonable given the inestimable benefits of receiving the sacraments during critical illness. Lay summary: Traditional pastoral visits to hospitalized patients might prove difficult or impossible for diseases that are contagious and highly fatal. This inquiry examines the feasibility, challenges, and logistical solutions to these visits. With input from bishops, priests, a canon lawyer, an epidemiologist, a physician, the CDC, and others, we conclude that pastoral visits are possible. Visits will require permission of health authorities, commitments of time, training, and a small but significant risk to the health of priests and others who volunteer for this ministry. PMID:25999614

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

    NASA Astrophysics Data System (ADS)

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

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

  10. 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.

  11. Alpha-synuclein spreading in Parkinson's disease.

    PubMed

    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 (α-syn) is the culprit. In the past few years, another piece of the puzzle has been added with data suggesting that α-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 α-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 α-syn, and discuss about the proper use of the term prion-like.

  12. 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.

  13. B cell epitope spreading: mechanisms and contribution to autoimmune diseases.

    PubMed

    Cornaby, Caleb; Gibbons, Lauren; Mayhew, Vera; Sloan, Chad S; Welling, Andrew; Poole, Brian D

    2015-01-01

    While a variety of factors act to trigger or initiate autoimmune diseases, the process of epitope spreading is an important contributor in their development. Epitope spreading is a diversification of the epitopes recognized by the immune system. This process happens to both T and B cells, with this review focusing on B cells. Such spreading can progress among multiple epitopes on a single antigen, or from one antigenic molecule to another. Systemic lupus erythematosus, multiple sclerosis, pemphigus, bullous pemphigoid and other autoimmune diseases, are all influenced by intermolecular and intramolecular B cell epitope spreading. Endocytic processing, antigen presentation, and somatic hypermutation act as molecular mechanisms that assist in driving epitope spreading and broadening the immune response in autoimmune diseases. The purpose of this review is to summarize our current understanding of B cell epitope spreading with regard to autoimmunity, how it contributes during the progression of various autoimmune diseases, and treatment options available.

  14. No evidence for contagious yawning in lemurs.

    PubMed

    Reddy, Rachna B; Krupenye, Christopher; MacLean, Evan L; Hare, Brian

    2016-09-01

    Among some haplorhine primates, including humans, relaxed yawns spread contagiously. Such contagious yawning has been linked to social bonds and empathy in some species. However, no studies have investigated contagious yawning in strepsirhines. We conducted an experimental study of contagious yawning in strepsirhines, testing ring-tailed and ruffed lemurs (n = 24) in a paradigm similar to one that has induced contagious yawning in haplorhines. First, in a control experiment, we investigated whether lemurs responded to projected video content in general (experiment 1). We showed them two videos to which we expected differential responses: one featured a terrestrial predator and the other a caretaker holding food. Next, to test for yawn contagion, we showed individual lemurs life-size video projections of groupmates and conspecific strangers yawning, and control footage of the same individuals at rest (experiment 2). Then, to examine whether a group context might enhance or allow for contagion, we exposed subjects to the same videos in a group setting (experiment 3). Lemurs produced alarm vocalizations and moved upward while viewing the predator, but not the caretaker, demonstrating that they do perceive video content meaningfully. However, lemurs did not yawn in response to yawning stimuli when tested alone, or with their groupmates. This study provides preliminary evidence that lemurs do not respond to yawning stimuli similarly to haplorhines, and suggests that this behavior may have evolved or become more exaggerated in haplorhines after the two major primate lineages split.

  15. Suppressing disease spreading by using information diffusion on multiplex networks

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Liu, Quan-Hui; Cai, Shi-Min; Tang, Ming; Braunstein, Lidia A.; Stanley, H. Eugene

    2016-07-01

    Although there is always an interplay between the dynamics of information diffusion and disease spreading, the empirical research on the systemic coevolution mechanisms connecting these two spreading dynamics is still lacking. Here we investigate the coevolution mechanisms and dynamics between information and disease spreading by utilizing real data and a proposed spreading model on multiplex network. Our empirical analysis finds asymmetrical interactions between the information and disease spreading dynamics. Our results obtained from both the theoretical framework and extensive stochastic numerical simulations suggest that an information outbreak can be triggered in a communication network by its own spreading dynamics or by a disease outbreak on a contact network, but that the disease threshold is not affected by information spreading. Our key finding is that there is an optimal information transmission rate that markedly suppresses the disease spreading. We find that the time evolution of the dynamics in the proposed model qualitatively agrees with the real-world spreading processes at the optimal information transmission rate.

  16. Blood discard rate and the prevalence of infectious and contagious diseases in blood donors from provincial towns of the state of Paraná, Brazil

    PubMed Central

    Borelli, Sueli Donizete; Mazzola, Jocimara Costa; Matta, Alessandra Cristina Gobbi; Takemoto, Angélica Yukari; Bértoli, Marta

    2013-01-01

    Background So that an improvement in the selection of donors can be achieved and the risk to the recipient of transfused blood can be reduced, prospective donors are submitted to clinical and serological screening. Objective This study investigated the blood discard rate and the rate of infectious and contagious diseases in blood donors from provincial towns of the state of Paraná, Brazil. Methods This study was an exploratory cross-sectional descriptive investigation with a quantitative approach of donations between January and December 2011. Results In the study period the Regional Blood center in Maringá, Brazil received 8337 blood donations from people living in the city and neighboring towns. However, 278 (3.33%) donations were discarded during serological screening owing to one or more positive serological markers. A total of 46.4% of the discarded blood units were confirmed positive by serology with anti-HBc being the most common (66.7%), followed by syphilis (22.5%), HBsAg (4.7%), anti-hepatitis C virus (3.1%), human immunodeficiency virus (1.5%) and Chagas' disease (1.5%). The rate of infectious-contagious diseases that can be transmitted by blood transfusions was 1.55% (129/8337) of the donor population with a frequency of 1.03% for anti-HBc and 0.35% for syphilis. Conclusion This study demonstrates a high prevalence of the anti-HBc marker in prospective blood donors from provincial towns in the state of Paraná, Brazil. PMID:24478604

  17. 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…

  18. 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

  19. Is heartworm disease really spreading in Europe?

    PubMed

    Genchi, Claudio; Rinaldi, L; Cascone, C; Mortarino, M; Cringoli, G

    2005-10-24

    Based on recently published surveys and newly acquired data, a study was conducted to verify the distribution of filarial worm (Filarioidea) infections in Europe, with particular emphasis on canine heartworm infection (Dirofilaria immitis). A Geographic Information System based on thermal regimen was constructed as a means to identify areas potentially suitable for heartworm transmission, taking into account that the development of D. immitis larvae in the mosquito does not occur below the threshold temperature of approximately 14 degrees C. Furthermore, a bionomic model of D. immitis in its mosquito vectors, which calculates the moving cumulative heartworm development unit parameter, was applied using the available temperature data to assess the theoretic transmission timing of heartworm in Europe. The results show that the earliest infection risk occurs in Spain on March 21 and the latest risk occurs in Spain on September 11. The longest risk period occurs in Spain (Murcia station: March 21-November 11), and the shortest risk period occurs in northeastern Europe. The study also provides the first risk assessment maps for Europe and suggests that if the actual climatic trend continues, filarial infection should spread into previously infection-free areas.

  20. 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…

  1. Voluntary vaccination strategy and the spread of sexually transmitted diseases.

    PubMed

    Xu, Fei; Cressman, Ross

    2016-04-01

    In this work, we investigate the spread and control of sexually transmitted diseases when a game-theory based vaccination strategy is involved. An individual's decision on vaccination uptake may follow a cost-benefit analysis since the individual obtains immunity against the disease from the vaccination and, at the same time, may have some perceived side effects. Evolutionary game theory is integrated into the epidemic model to reveal the relationship between individuals' voluntary decisions on vaccination uptake and the spread and control of such diseases. We show that decreasing the perceived cost of taking vaccine or increasing the payoff from social obligation is beneficial to controlling the disease. It is also shown how the "degree of rationality" of males and females affects the disease spread through the net payoff of the game. In particular, individual awareness of the consequences of the disease on the infectives also contributes to slowing down the disease spread. By analyzing an asymmetric version of our evolutionary game, it is shown that the disease is better controlled when individuals are more sensitive to fitness differences when net payoff is positive than when it is negative.

  2. Cooperative Crisis Management and Avian Influenza. A Risk Assessment Guide for International Contagious Disease Prevention and Risk Mitigation

    DTIC Science & Technology

    2006-03-01

    immediate demands. To some, the 1918 influenza pandemic seems like ancient history , so when comparisons are made between the devastation almost a century... history as a mirror and looks to the future, the 1918–1919 influenza pandemic provides a stark perspective on a potential avian influenza pandemic. The...quail, geese, felids, rodents, and swine are just some of the species susceptible to influenza A. The mechanisms of the spread of influenza virus

  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.

  4. Spreading disease: integro-differential equations old and new.

    PubMed

    Medlock, Jan; Kot, Mark

    2003-08-01

    We investigate an integro-differential equation for a disease spread by the dispersal of infectious individuals and compare this to Mollison's [Adv. Appl. Probab. 4 (1972) 233; D. Mollison, The rate of spatial propagation of simple epidemics, in: Proc. 6th Berkeley Symp. on Math. Statist. and Prob., vol. 3, University of California Press, Berkeley, 1972, p. 579; J. R. Statist. Soc. B 39 (3) (1977) 283] model of a disease spread by non-local contacts. For symmetric kernels with moment generating functions, spreading infectives leads to faster traveling waves for low rates of transmission, but to slower traveling waves for high rates of transmission. We approximate the shape of the traveling waves for the two models using both piecewise linearization and a regular-perturbation scheme.

  5. Disease spread in age structured populations with maternal age effects.

    PubMed

    Clark, Jessica; Garbutt, Jennie S; McNally, Luke; Little, Tom J

    2017-04-01

    Fundamental ecological processes, such as extrinsic mortality, determine population age structure. This influences disease spread when individuals of different ages differ in susceptibility or when maternal age determines offspring susceptibility. We show that Daphnia magna offspring born to young mothers are more susceptible than those born to older mothers, and consider this alongside previous observations that susceptibility declines with age in this system. We used a susceptible-infected compartmental model to investigate how age-specific susceptibility and maternal age effects on offspring susceptibility interact with demographic factors affecting disease spread. Our results show a scenario where an increase in extrinsic mortality drives an increase in transmission potential. Thus, we identify a realistic context in which age effects and maternal effects produce conditions favouring disease transmission.

  6. Eco-social processes influencing infectious disease emergence and spread.

    PubMed

    Jones, Bryony A; Betson, Martha; Pfeiffer, Dirk U

    2017-01-01

    The complexity and connectedness of eco-social processes have major influence on the emergence and spread of infectious diseases amongst humans and animals. The disciplinary nature of most research activity has made it difficult to improve our understanding of interactions and feedback loops within the relevant systems. Influenced by the One Health approach, increasing efforts have recently been made to address this knowledge gap. Disease emergence and spread is strongly influenced by host density and contact structures, pathogen characteristics and pathogen population and molecular evolutionary dynamics in different host species, and host response to infection. All these mechanisms are strongly influenced by eco-social processes, such as globalization and urbanization, which lead to changes in global ecosystem dynamics, including patterns of mobility, human population density and contact structures, and food production and consumption. An improved understanding of epidemiological and eco-social processes, including their interdependence, will be essential to be able to manage diseases in these circumstances. The interfaces between wild animals, domestic animals and humans need to be examined to identify the main risk pathways and put in place appropriate mitigation. Some recent examples of emerging infectious disease are described to illustrate eco-social processes that are influencing disease emergence and spread.

  7. 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, α-synuclein, polyglutamine-containing proteins, and amyloid-β, 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 α-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

  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. 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

  10. 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.

  11. Spreading disease: a controversy concerning the metaphysics of disease.

    PubMed

    D'Amico, R

    1998-01-01

    This article concerns the metaphysics of disease. Is disease a fixed feature of the world or a social value or preference? I argue that disease is not a value-laden concept and thus debates concerning it differ fundamentally from debates concerning health, harm, or suffering where evaluative judgements are central. I show how the so-called social constructionist view of disease has been motivated both by ethical concerns with medical practices and general theoretical doubts about scientific naturalism. If I can show that ethical concerns about medical treatment can be answered without adopting social constructionism, that leaves only the broader theoretical question of naturalism. I cannot completely answer those theoretical doubts, but I show that the theoretical motivation is less convincing when it is separated from the moral challenge often accompanying it. I conclude that a convincing defense of the non-naturalistic conception of disease is rarely attempted and proves more difficult and counter-intuitive than its proponents assume.

  12. More than a Rumor Spreads in Parkinson's Disease

    PubMed Central

    Prymaczok, Natalia C.; Riek, Roland; Gerez, Juan

    2016-01-01

    As Parkinson's disease progresses, a massive loss of dopaminergic neurons is accompanied by accumulation of alpha-Synuclein (αSyn) neuronal inclusions called Lewy bodies and Lewy neurites. Inclusions first appear in olfactory bulb and enteric neurons then in ascendant neuroanatomical interconnected areas, and finally, in late stages of the disease, Lewy bodies are observed in a substantia nigra pars compacta with clear signs of neuronal loss. It is believed that the spreading of Lewy bodies through the nervous system is a consequence of the cell-to-cell propagation of αSyn, that can occur via sequential steps of secretion and uptake. Certain pathological forms of transmitted αSyn are able to seed endogenous counterparts in healthy recipient cells, thus promoting the self-sustained cycle of inclusion formation, amplification and spreading, that ultimately underlies disease progression. Here we review the cell-to-cell propagation of αSyn focusing on its role in the progression of Parkinson's disease. PMID:27994545

  13. More than a Rumor Spreads in Parkinson's Disease.

    PubMed

    Prymaczok, Natalia C; Riek, Roland; Gerez, Juan

    2016-01-01

    As Parkinson's disease progresses, a massive loss of dopaminergic neurons is accompanied by accumulation of alpha-Synuclein (αSyn) neuronal inclusions called Lewy bodies and Lewy neurites. Inclusions first appear in olfactory bulb and enteric neurons then in ascendant neuroanatomical interconnected areas, and finally, in late stages of the disease, Lewy bodies are observed in a substantia nigra pars compacta with clear signs of neuronal loss. It is believed that the spreading of Lewy bodies through the nervous system is a consequence of the cell-to-cell propagation of αSyn, that can occur via sequential steps of secretion and uptake. Certain pathological forms of transmitted αSyn are able to seed endogenous counterparts in healthy recipient cells, thus promoting the self-sustained cycle of inclusion formation, amplification and spreading, that ultimately underlies disease progression. Here we review the cell-to-cell propagation of αSyn focusing on its role in the progression of Parkinson's disease.

  14. Is Cellulitis Contagious?

    MedlinePlus

    ... isn't usually spread from person to person. Cellulitis is an infection of the deeper layers of the skin most ... chills Swollen glands or lymph nodes Left untreated, cellulitis can rapidly ... soft tissue infections. In: Rosen's Emergency Medicine: Concepts and Clinical Practice. ...

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Stomach Flu: How Long Am I Contagious?

    MedlinePlus

    ... am I contagious if I have the stomach flu? Answers from James M. Steckelberg, M.D. You can be contagious ... depending on which virus is causing your stomach flu (gastroenteritis). A number of viruses can cause gastroenteritis, ...

  20. How Long Is Mono Contagious?

    MedlinePlus

    ... it is contagious. Once someone gets mono, the virus stays in that person's body for life. That doesn't mean that you are always ... as long as 18 months. After that, the virus remains dormant (inactive) in the body for the rest of a person's life. If you've had mono, the virus can ...

  1. Prevention of spread of communicable disease by air travel.

    PubMed

    Evans, Anthony D; Thibeault, Claude

    2009-07-01

    Mathematical modeling suggests that travel restrictions are likely to have only a limited effect on minimizing the spread of disease. Nevertheless, medical screening of travelers remains an option to be considered in a risk-reduction strategy. Screening of departing and/or arriving travelers are possibilities, although the World Health Organization (WHO) favors the former as it is normally easier to geographically contain a disease prior to its transmission outside the outbreak area. Apart from airport screening, several other related issues require consideration, including: transmission of disease on board aircraft; transmission of disease in airport terminal buildings; and contact tracing. A major challenge is to ensure adequate resources are devoted to pandemic preparedness planning in the aviation sector, which may not be fully considered in a national preparedness plan. This is because the prevention of accidents occupies most of the attention of regulatory aviation authorities, and public health authorities do not always see aviation as a priority area. Chief medical officers of regulatory authorities may be in a position to facilitate collaboration between the many stakeholders involved in preparedness planning for aviation.

  2. Contagious Yawning in Autistic and Typical Development

    ERIC Educational Resources Information Center

    Helt, Molly S.; Eigsti, Inge-Marie; Snyder, Peter J.; Fein, Deborah A.

    2010-01-01

    The authors tested susceptibility to contagious yawning in 120 children, 1-6 years, to identify the time course of its emergence during development. Results indicated a substantial increase in the frequency of contagious yawning at 4 years. In a second study, the authors examined contagious yawning in 28 children with autism spectrum disorders…

  3. Global analysis for spread of infectious diseases via transportation networks.

    PubMed

    Nakata, Yukihiko; Röst, Gergely

    2015-05-01

    We formulate an epidemic model for the spread of an infectious disease along with population dispersal over an arbitrary number of distinct regions. Structuring the population by the time elapsed since the start of travel, we describe the infectious disease dynamics during transportation as well as in the regions. As a result, we obtain a system of delay differential equations. We define the basic reproduction number R(0) as the spectral radius of a next generation matrix. For multi-regional systems with strongly connected transportation networks, we prove that if R(0) ≤ 1 then the disease will be eradicated from each region, while if R(0) > 1 there is a globally asymptotically stable equilibrium, which is endemic in every region. If the transportation network is not strongly connected, then the model analysis shows that numerous endemic patterns can exist by admitting a globally asymptotically stable equilibrium, which may be disease free in some regions while endemic in other regions. We provide a procedure to detect the disease free and the endemic regions according to the network topology and local reproduction numbers. The main ingredients of the mathematical proofs are the inductive applications of the theory of asymptotically autonomous semiflows and cooperative dynamical systems. We visualise stability boundaries of equilibria in a parameter plane to illustrate the influence of the transportation network on the disease dynamics. For a system consisting of two regions, we find that due to spatial heterogeneity characterised by different local reproduction numbers, R(0) may depend non-monotonically on the dispersal rates, thus travel restrictions are not always beneficial.

  4. Dermoscopy of Pigmented Bowen's Disease Mimicking Early Superficial Spreading Melanoma

    PubMed Central

    Hayashi, Yuka; Tanaka, Masaru; Suzaki, Reiko; Mori, Nuiko; Konohana, Izumi

    2009-01-01

    A 89-year-old Japanese woman presented at our clinic because of a several months’ history of an asymptomatic gradually enlarging pigmented skin lesion on the dorsum of the left foot. Physical examination revealed a single hyperpigmented oval macule of 5 mm with a rough surface. The color of the lesion was dark brown to light brown. Dermoscopic examination demonstrated atypical pigment network with small dotted vessels. Irregular streaks were also partially noted at the periphery. We suspected superficial spreading melanoma and performed an excision. The histologic features were consistent with a diagnosis of pigmented Bowen's disease. We could not completely account for dermoscopic aspects from the pathological findings of hematoxylin and eosin-stained specimens; therefore, specimens were stained with Fontana-Masson stain. It clearly demonstrated the distribution of melanin in the epidermis. We concluded that atypical network was due to an uneven melanin deposition in the variably thickened epidermal rete ridges. PMID:20652107

  5. Does genetic diversity limit disease spread in natural host populations?

    PubMed Central

    King, K C; Lively, C M

    2012-01-01

    It is a commonly held view that genetically homogenous host populations are more vulnerable to infection than genetically diverse populations. The underlying idea, known as the ‘monoculture effect,' is well documented in agricultural studies. Low genetic diversity in the wild can result from bottlenecks (that is, founder effects), biparental inbreeding or self-fertilization, any of which might increase the risk of epidemics. Host genetic diversity could buffer populations against epidemics in nature, but it is not clear how much diversity is required to prevent disease spread. Recent theoretical and empirical studies, particularly in Daphnia populations, have helped to establish that genetic diversity can reduce parasite transmission. Here, we review the present theoretical work and empirical evidence, and we suggest a new focus on finding ‘diversity thresholds.' PMID:22713998

  6. Behavioral connectivity among bighorn sheep suggests potential for disease spread

    USGS Publications Warehouse

    Borg, Nathan J.; Mitchell, Michael S.; Lukacs, Paul M.; Mack, Curt M.; Waits, Lisette P.; Krausman, Paul R.

    2017-01-01

    Connectivity is important for population persistence and can reduce the potential for inbreeding depression. Connectivity between populations can also facilitate disease transmission; respiratory diseases are one of the most important factors affecting populations of bighorn sheep (Ovis canadensis). The mechanisms of connectivity in populations of bighorn sheep likely have implications for spread of disease, but the behaviors leading to connectivity between bighorn sheep groups are not well understood. From 2007–2012, we radio-collared and monitored 56 bighorn sheep in the Salmon River canyon in central Idaho. We used cluster analysis to define social groups of bighorn sheep and then estimated connectivity between these groups using a multi-state mark-recapture model. Social groups of bighorn sheep were spatially segregated and linearly distributed along the Salmon River canyon. Monthly probabilities of movement between adjacent male and female groups ranged from 0.08 (±0.004 SE) to 0.76 (±0.068) for males and 0.05 (±0.132) to 0.24 (±0.034) for females. Movements of males were extensive and probabilities of movement were considerably higher during the rut. Probabilities of movement for females were typically smaller than those of males and did not change seasonally. Whereas adjacent groups of bighorn sheep along the Salmon River canyon were well connected, connectivity between groups north and south of the Salmon River was limited. The novel application of a multi-state model to a population of bighorn sheep allowed us to estimate the probability of movement between adjacent social groups and approximate the level of connectivity across the population. Our results suggest high movement rates of males during the rut are the most likely to result in transmission of pathogens among both male and female groups. Potential for disease spread among female groups was smaller but non-trivial. Land managers can plan grazing of domestic sheep for spring and summer

  7. 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....

  8. 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....

  9. Neighbourhood control policies and the spread of infectious diseases.

    PubMed Central

    Matthews, L; Haydon, D T; Shaw, D J; Chase-Topping, M E; Keeling, M J; Woolhouse, M E J

    2003-01-01

    We present a model of a control programme for a disease outbreak in a population of livestock holdings. Control is achieved by culling infectious holdings when they are discovered and by the pre-emptive culling of livestock on holdings deemed to be at enhanced risk of infection. Because the pre-emptive control programme cannot directly identify exposed holdings, its implementation will result in the removal of both infected and uninfected holdings. This leads to a fundamental trade-off: increased levels of control produce a greater reduction in transmission by removing more exposed holdings, but increase the number of uninfected holdings culled. We derive an expression for the total number of holdings culled during the course of an outbreak and demonstrate that there is an optimal control policy, which minimizes this loss. Using a metapopulation model to incorporate local clustering of infection, we examine a neighbourhood control programme in a locally spreading outbreak. We find that there is an optimal level of control, which increases with increasing basic reproduction ratio, R(0); moreover, implementation of control may be optimal even when R(0) < 1. The total loss to the population is relatively insensitive to the level of control as it increases beyond the optimal level, suggesting that over-control is a safer policy than under-control. PMID:12964992

  10. Developmental and comparative perspectives of contagious yawning.

    PubMed

    Senju, Atsushi

    2010-01-01

    Contagious yawning (i.e. yawning triggered by perceiving others' yawning) is a well-documented phenomenon, but the mechanism underlying it is still unclear. In this chapter, I review the current evidence about: (1) developmental studies with typically and atypically developing populations, and (2) comparative studies in non-human animals. Developmental studies have revealed that contagious yawning is disturbed in individuals with autism spectrum disorders, suggesting that contagious yawning may share a developmental basis with the capacity for theory of mind. Comparative studies have suggested that contagious yawning can be observed in non-primate species, such as domestic dogs. As dogs are known to have exceptional skills in communicating with humans, it has also been suggested that contagious yawning may be related to the capacity for social communication. These results from developmental and comparative studies are consistent with the claim that the mechanism underlying contagious yawning relates to the capacity for empathy.

  11. Contagious yawning in autistic and typical development.

    PubMed

    Helt, Molly S; Eigsti, Inge-Marie; Snyder, Peter J; Fein, Deborah A

    2010-01-01

    The authors tested susceptibility to contagious yawning in 120 children, 1-6 years, to identify the time course of its emergence during development. Results indicated a substantial increase in the frequency of contagious yawning at 4 years. In a second study, the authors examined contagious yawning in 28 children with autism spectrum disorders (ASD), 6-15 years. Children with ASD showed diminished susceptibility to contagious yawning compared with 2 control groups matched for mental and chronological age, respectively. In addition, children diagnosed with Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS) a milder variant of autism, were more susceptible to contagious yawning than were children diagnosed with full Autistic Disorder. The authors explore the implications of these findings for theories about the development of mimicry and emotional contagion.

  12. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prevention of the introduction, transmission, or spread of communicable diseases. 1271.145 Section 1271.145 Food and Drugs FOOD AND DRUG ADMINISTRATION... Tissue Practice § 1271.145 Prevention of the introduction, transmission, or spread of...

  13. 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

  14. Control of the deliberate spread of foot-and-mouth disease virus.

    PubMed

    Farsang, Attila; Frentzel, Hendrik; Kulcsár, Gábor; Soós, Tibor

    2013-09-01

    Foot-and-mouth disease (FMD) is one of the most feared of transboundary animal diseases. Accidental or deliberate release of the causative agent can have both direct and indirect effects that result in massive economic losses and disruption. The direct effects of an FMD outbreak include immediate losses to agricultural production and disruption of local economies, while the indirect effects are mainly related to disease control measures such as restriction of market access at local and global levels and the high costs of disease control. To improve the capacity of the European Union (EU) to counter animal bioterrorism threats, AniBioThreat was launched with a special focus on threats to living animals, feed, and food of animal origin. As part of this project, several zoonotic or animal pathogenic agents are considered from different perspectives. FMD virus was selected as one agent to be scrutinized because it is highly contagious and an outbreak can have a severe economic impact. Ways to fight a deliberate outbreak can be demonstrated through the example of FMD. In this article, the virology and epidemiology of FMD virus are discussed with special attention to the related law enforcement aspects.

  15. Modelling the influence of human behaviour on the spread of infectious diseases: a review.

    PubMed

    Funk, Sebastian; Salathé, Marcel; Jansen, Vincent A A

    2010-09-06

    Human behaviour plays an important role in the spread of infectious diseases, and understanding the influence of behaviour on the spread of diseases can be key to improving control efforts. While behavioural responses to the spread of a disease have often been reported anecdotally, there has been relatively little systematic investigation into how behavioural changes can affect disease dynamics. Mathematical models for the spread of infectious diseases are an important tool for investigating and quantifying such effects, not least because the spread of a disease among humans is not amenable to direct experimental study. Here, we review recent efforts to incorporate human behaviour into disease models, and propose that such models can be broadly classified according to the type and source of information which individuals are assumed to base their behaviour on, and according to the assumed effects of such behaviour. We highlight recent advances as well as gaps in our understanding of the interplay between infectious disease dynamics and human behaviour, and suggest what kind of data taking efforts would be helpful in filling these gaps.

  16. Presence of contagious yawning in sheep.

    PubMed

    Yonezawa, Tomohiro; Sato, Kohei; Uchida, Mona; Matsuki, Naoaki; Yamazaki, Atusi

    2017-01-01

    Contagious yawning is triggered by others yawning, and it has previously been reported in humans, primates and several experimental and companion mammals. Whereas it might be a response to an innate releasing mechanism, contagious yawning is also considered to involve emotional contagion. Here, we demonstrate that sheep, the animal model of livestock animals, also experience contagious yawning. Twelve adult castrated Corriedale sheep were used in this study. Pairs of sheep were adjacently restrained with or without a wooden divider panel to shield them from viewing the other. Their behaviors were video-recorded for 3 days in each condition. Sheep yawned 2.0 ± 1.1 and 1.2 ± 1.1 times/day/head in the unshielded and shielded conditions, respectively. Unshielded restrained sheep yawned within 1 min after the other one 11.1% of the time, while shielded pairs did not exhibit contagious yawning. Rumination was also highly synchronized under the unshielded condition. These data reveal that contagious yawning and behavioral synchronicity occur in ruminants like sheep, making them a suitable animal model to investigate contagious yawning and the underlying mechanism.

  17. Simulation of between-farm transmission of porcine reproductive and respiratory syndrome virus in Ontario, Canada using the North American Animal Disease Spread Model.

    PubMed

    Thakur, Krishna K; Revie, Crawford W; Hurnik, Daniel; Poljak, Zvonimir; Sanchez, Javier

    2015-03-01

    Porcine reproductive and respiratory syndrome (PRRS), a viral disease of swine, has major economic impacts on the swine industry. The North American Animal Disease Spread Model (NAADSM) is a spatial, stochastic, farm level state-transition modeling framework originally developed to simulate highly contagious and foreign livestock diseases. The objectives of this study were to develop a model to simulate between-farm spread of a homologous strain of PRRS virus in Ontario swine farms via direct (animal movement) and indirect (sharing of trucks between farms) contacts using the NAADSM and to compare the patterns and extent of outbreak under different simulated conditions. A total of 2552 swine farms in Ontario province were allocated to each census division of Ontario and geo-locations of the farms were randomly generated within the agriculture land of each Census Division. Contact rates among different production types were obtained using pig movement information from four regions in Canada. A total of 24 scenarios were developed involving various direct (movement of infected animals) and indirect (pig transportation trucks) contact parameters in combination with alternating the production type of the farm in which the infection was seeded. Outbreaks were simulated for one year with 1000 replications. The median number of farms infected, proportion of farms with multiple outbreaks and time to reach the peak epidemic were used to compare the size, progression and extent of outbreaks. Scenarios involving spread only by direct contact between farms resulted in outbreaks where the median percentage of infected farms ranged from 31.5 to 37% of all farms. In scenarios with both direct and indirect contact, the median percentage of infected farms increased to a range from 41.6 to 48.6%. Furthermore, scenarios with both direct and indirect contact resulted in a 44% increase in median epidemic size when compared to the direct contact scenarios. Incorporation of both animal

  18. 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.

  19. 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.

  20. Disease spread, susceptibility and infection intensity: vicious circles?

    PubMed

    Beldomenico, Pablo M; Begon, Michael

    2010-01-01

    Epidemiological models and studies of disease ecology typically ignore the role of host condition and immunocompetence when trying to explain the distribution and dynamics of infections and their impact on host dynamics. Recent research, however, indicates that host susceptibility should be considered carefully if we are to understand the mechanism by which parasite dynamics influence host dynamics and vice versa. Studies in insects, fish, amphibians and rodents show that infection occurrence and intensity are more probable and more severe in individuals with an underlying poor condition. Moreover, infection itself results in further deterioration of the host and a 'vicious circle' is created. We argue that this potential synergy between host susceptibility and infection should be more widely acknowledged in disease ecology research.

  1. On the Spread of Drug-Resistant Diseases

    NASA Astrophysics Data System (ADS)

    Schinazi, Rinaldo B.

    1999-10-01

    We introduce an interacting particle system to model the emergence of drug-resistant diseases, one of the most serious health problems in modern society. We are interested in diseases for which a natural strain may mutate into a drug-resistant strain. This happens, for instance, when antibiotics are misused. The main result of our analysis is that with an efficient drug against the natural strain, if there is even a small chance that the natural strain mutates into the drug-resistant one, then there will eventually be an outbreak of the drug-resistant strain throughout the population. In that case the natural strain disappears and is replaced by the drug-resistant strain. The disturbing part of this is that an efficient treatment of the natural strain gives an edge to the drug-resistant strain.

  2. Spread rate of lumpy skin disease in the Balkans, 2015-2016.

    PubMed

    Mercier, A; Arsevska, E; Bournez, L; Bronner, A; Calavas, D; Cauchard, J; Falala, S; Caufour, P; Tisseuil, C; Lefrançois, T; Lancelot, R

    2017-02-26

    After its introduction in Turkey in November 2013 and subsequent spread in this country, lumpy skin disease (LSD) was first reported in the western Turkey in May 2015. It was observed in cattle in Greece and reported to the World Organization for Animal Health (OIE) in August 2015. From May 2015 to August 2016, 1,092 outbreaks of lumpy skin disease were reported in cattle from western Turkey and eight Balkan countries: Greece, Bulgaria, The Former Yugoslav Republic of Macedonia, Serbia, Kosovo, and Albania. During this period, the median LSD spread rate was 7.3 km/week. The frequency of outbreaks was highly seasonal, with little or no transmission reported during the winter. Also, the skewed distribution of spread rates suggested two distinct underlying epidemiological processes, associating local and distant spread possibly related to vectors and cattle trade movements, respectively.

  3. Adults' Explanations and Children's Understanding of Contagious Illnesses, Non-Contagious Illnesses, and Injuries

    ERIC Educational Resources Information Center

    Toyama, Noriko

    2016-01-01

    The present study examined (1) whether children notice different causes for contagious illnesses, non-contagious illnesses, and injuries and (2) what information adults provide to children and to what extent this information is related to children's causal awareness. Studies 1 and 2 explored preschool teachers' and mothers' explanations of…

  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. 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.

  6. 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...

  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. Epidemic spreading of interacting diseases with activity of nodes reshapes the critical threshold

    NASA Astrophysics Data System (ADS)

    Fan, Chongjun; Jin, Yang; Huo, Liang-An; Liu, Chen; Yang, Yunpeng

    In this paper, based on susceptible-infected-susceptible (SIS) scheme, we introduce a framework that allows us to describe the spreading dynamics of two interacting diseases with active nodes. Different from previous studies, the two different diseases, propagating concurrently on the same population, can interact with each other by modifying their transmission rates. Meanwhile, according to certain probabilities, each node on the complex networks rotates between active state and inactive state. Based on heterogeneous mean-field approach, we analyze the epidemic thresholds of the two diseases and compute the temporal evolution characterizing the spreading dynamics. In addition, we validate these theoretical predictions by numerical simulations with phase diagrams. Results show that the secondary thresholds for the two opposite scenarios (mutual enhancement scenario and mutual impairment scenario) are different. We also find that the value of critical threshold and the final size of spreading dynamics are reduced as the node activity rate decreases.

  9. [Spreading experience of demonstration plots and strengthening control of parasitic diseases].

    PubMed

    Yu, Wang

    2011-10-01

    This paper summarizes the achievements and experiences of demonstration plots carrying out comprehensive control measures of parasite diseases in China, and elaborates the hard task of the control of parasitic diseases as one of main public health problems. The article also elaborates the significance of spreading the experiences of demonstration plots carrying out comprehensive control measures of parasite diseases for improving the health of people and promoting the construction of new countryside.

  10. Using the gravity model to estimate the spatial spread of vector-borne diseases.

    PubMed

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

    2012-11-30

    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.

  11. 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

  12. Spreading dynamics and synchronization behavior of periodic diseases on complex networks

    NASA Astrophysics Data System (ADS)

    Xu, Degang; Xu, Xiyang; Yang, Chunhua; Gui, Weihua

    2017-01-01

    A new discrete-susceptible-infected-recovered-susceptible (DSIRS) model is introduced in this paper to investigate the disease spreading dynamics and synchronization behavior on complex networks. In the model, every node is considered independently rather than as a part of one group that has a common node state in complex networks. The synchronization phenomenon of epidemic spreading based on the model in random networks and scale-free networks is analyzed. Synchronization is affected by the infection duration, the complete cycle duration and the topological network structure, which affects the immune strategy. Accordingly, immune strategies including the maximum degree immune strategy and the nearest immune strategy are proposed to prevent disease propagating.

  13. Do dogs (Canis familiaris) show contagious yawning?

    PubMed

    Harr, Aimee L; Gilbert, Valerie R; Phillips, Kimberley A

    2009-11-01

    We report an experimental investigation into whether domesticated dogs display contagious yawning. Fifteen dogs were shown video clips of (1) humans and (2) dogs displaying yawns and open-mouth expressions (not yawns) to investigate whether dogs showed contagious yawning to either of these social stimuli. Only one dog performed significantly more yawns during or shortly after viewing yawning videos than to the open-mouth videos, and most of these yawns occurred to the human videos. No dogs showed significantly more yawning to the open-mouth videos (human or dog). The percentage of dogs showing contagious yawning was less than chimpanzees and humans showing this behavior, and considerably less than a recently published report investigating this behavior in dogs (Joly-Mascheroni et al. in Biol Lett 4:446-448, 2008).

  14. Disease risk in a dynamic environment: the spread of tick-borne pathogens in Minnesota, USA.

    PubMed

    Robinson, Stacie J; Neitzel, David F; Moen, Ronald A; Craft, Meggan E; Hamilton, Karin E; Johnson, Lucinda B; Mulla, David J; Munderloh, Ulrike G; Redig, Patrick T; Smith, Kirk E; Turner, Clarence L; Umber, Jamie K; Pelican, Katharine M

    2015-03-01

    As humans and climate change alter the landscape, novel disease risk scenarios emerge. Understanding the complexities of pathogen emergence and subsequent spread as shaped by landscape heterogeneity is crucial to understanding disease emergence, pinpointing high-risk areas, and mitigating emerging disease threats in a dynamic environment. Tick-borne diseases present an important public health concern and incidence of many of these diseases are increasing in the United States. The complex epidemiology of tick-borne diseases includes strong ties with environmental factors that influence host availability, vector abundance, and pathogen transmission. Here, we used 16 years of case data from the Minnesota Department of Health to report spatial and temporal trends in Lyme disease (LD), human anaplasmosis, and babesiosis. We then used a spatial regression framework to evaluate the impact of landscape and climate factors on the spread of LD. Finally, we use the fitted model, and landscape and climate datasets projected under varying climate change scenarios, to predict future changes in tick-borne pathogen risk. Both forested habitat and temperature were important drivers of LD spread in Minnesota. Dramatic changes in future temperature regimes and forest communities predict rising risk of tick-borne disease.

  15. 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

  16. 21 CFR 1271.145 - Prevention of the introduction, transmission, or spread of communicable diseases.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prevention of the introduction, transmission, or... Tissue Practice § 1271.145 Prevention of the introduction, transmission, or spread of communicable diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test...

  17. 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.

  18. 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

  19. 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…

  20. High Court Rules that Law Bars Bias against Persons with Contagious Ills.

    ERIC Educational Resources Information Center

    Fields, Cheryl M.

    1987-01-01

    The Supreme Court has ruled that Section 504 of the Rehabilitation Act of 1973, which protects disabled people from discrimination, covers persons with contagious diseases. This decision is seen as strengthening the rights of people suffering from AIDS as well as other diseases. (MSE)

  1. EXPERIMENTS ON THE EPIDEMIOLOGY OF PSEUDORABIES : I. MODE OF TRANSMISSION OF THE DISEASE IN SWINE AND THEIR POSSIBLE ROLE IN ITS SPREAD TO CATTLE.

    PubMed

    Shope, R E

    1935-06-30

    Pseudorabies is a very fatal but non-contagious disease in cattle and the common laboratory animals. It is a relatively mild yet highly contagious disease in swine. It has been shown that in swine the nose serves both for the entrance and the exit of the virus. Furthermore, it has been observed that fatal pseudorabies infections in rabbits can be induced merely by bringing their abraded skin into contact with the noses of infected swine. The blood sera of swine on two farms where pseudorabies had occurred among the cattle were found to be capable of neutralizing pseudorabies virus. It is believed that in these instances the swine had a mild and unrecognized pseudorabies infection and transmitted their disease to the cattle with which they were associated, by transfer of the virus on their noses to the abraded skin of the cattle.

  2. Disease Spread through Animal Movements: A Static and Temporal Network Analysis of Pig Trade in Germany

    PubMed Central

    Lentz, Hartmut H. K.; Koher, Andreas; Hövel, Philipp; Gethmann, Jörn; Sauter-Louis, Carola; Selhorst, Thomas; Conraths, Franz J.

    2016-01-01

    Background Animal trade plays an important role for the spread of infectious diseases in livestock populations. The central question of this work is how infectious diseases can potentially spread via trade in such a livestock population. We address this question by analyzing the underlying network of animal movements. In particular, we consider pig trade in Germany, where trade actors (agricultural premises) form a complex network. Methodology The considered pig trade dataset spans several years and is analyzed with respect to its potential to spread infectious diseases. Focusing on measurements of network-topological properties, we avoid the usage of external parameters, since these properties are independent of specific pathogens. They are on the contrary of great importance for understanding any general spreading process on this particular network. We analyze the system using different network models, which include varying amounts of information: (i) static network, (ii) network as a time series of uncorrelated snapshots, (iii) temporal network, where causality is explicitly taken into account. Findings We find that a static network view captures many relevant aspects of the trade system, and premises can be classified into two clearly defined risk classes. Moreover, our results allow for an efficient allocation strategy for intervention measures using centrality measures. Data on trade volume do barely alter the results and is therefore of secondary importance. Although a static network description yields useful results, the temporal resolution of data plays an outstanding role for an in-depth understanding of spreading processes. This applies in particular for an accurate calculation of the maximum outbreak size. PMID:27152712

  3. 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.

  4. [Sanitary control of the territory: data bases on the spread of some quarantine infections].

    PubMed

    Prometnoĭ, V I; Golubev, B P; Moskovitina, E A

    2002-01-01

    The data bases (DB) on the spread of plague, yellow fever and contagious virus hemorrhagic fevers (CVHF) in foreign countries have been created. These DB contain information on the main international air and sea ports and their relationships with natural focal territories. The data base "Sanitary control. Yellow fever" contains information on different species serving as vectors for yellow fever virus. Information on the circulation of the causative agents of Ebola fever, Lassa fever and Marburg disease in African countries has been introduced into DB, the differentiation of countries by the degree of the potential danger of the CVHF spread has been made.

  5. The spreading dynamics of sexually transmitted diseases with birth and death on heterogeneous networks

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Cao, Jinde; Alsaedi, Ahmed; Hayat, Tasawar

    2017-02-01

    In this paper, we formulate a deterministic model by including the vacant sites, which represent inactive individuals or potential contacts, to investigate the spreading dynamics of sexually transmitted diseases in heterogeneous networks. We first analytically derive the basic reproduction number R 0, which completely determines global dynamics of the system in the long run. Specifically, if R 0  <  1, the disease-free equilibrium is globally asymptotically stable, i.e. disease disappears from the network irrespective of initial infected numbers and distributions, whereas if R 0  >  1, the system is uniformly persistent around a unique endemic equilibrium, i.e. disease persists in the network. Furthermore, by using a suitable Lyapunov function the global stability of endemic equilibrium for low/high-risk infected individuals only is proved. Finally, the effects of three immunization schemes are studied and compared, and extensive numerical simulations are performed to investigate the effect of network topology and population turnover on disease spread. Our results suggest that population turnover could have great impact on the sexually transmitted disease system in heterogeneous networks, including the basic reproduction number and infection prevalence.

  6. An investigation of auditory contagious yawning.

    PubMed

    Arnott, Stephen R; Singhal, Anthony; Goodale, Melvyn A

    2009-09-01

    Despite a widespread familiarity with the often compelling urge to yawn after perceiving someone else yawn, an understanding of the neural mechanism underlying contagious yawning remains incomplete. In the present auditory fMRI study, listeners used a 4-point scale to indicate how much they felt like yawning following the presentation of a yawn, breath, or scrambled yawn sound. Not only were yawn sounds given significantly higher ratings, a trait positively correlated with each individual's empathy measure, but relative to control stimuli, random effects analyses revealed enhanced hemodynamic activity in the right posterior inferior frontal gyrus (pIFG) in response to hearing yawns. Moreover, pIFG activity was greatest for yawn stimuli associated with high as opposed to low yawn ratings and for control sounds associated with equally high yawn ratings. These results support a relationship between contagious yawning and empathy and provide evidence for pIFG involvement in contagious yawning. A supplemental figure for this study may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.

  7. Louis Willems (1822-1907) and the immunization against contagious bovine pleuropneumonia. An evaluation.

    PubMed

    Huygelen, C

    1997-01-01

    Louis Willems's name is intimately linked with the history of prophylactic immunization in the nineteenth century. When he obtained his medical degree in 1849 contagious bovine pleuropneumonia or lung sickness was raging among the cattle population in most European countries. As the son of a cattle fattener Willems was confronted directly with the problem in his father's stables and decided to study the disease and to search for a remedy to combat it. The disease is caused by Mycoplasma mycoides and subspecies mycoides, but in the middle of the nineteenth century during the battle between the miasmatists and the contagionists, many had doubts about its contagiousness. Willems defended from the start the contagiousness of the disease and noticed that animals who had survived an infection did not contract it a second time. He demonstrated that inoculation of the serous fluid from the lungs or from the pleural cavity of affected animals into healthy cattle led to pronounced local reactions. When these inoculated animals later on came into contact with diseased cattle they were shown to be immune. In his first trials he inoculated at the base of the tail or around the nostrils but this led to very severe reactions and frequently to death. He then started inoculating at the tip of the tail with much better results. Most animals showed a more or less pronounced reaction at the inoculation site and about seven percent lost their tail partially or completely through necrosis, but the mortality remained very limited. The local reactions were caused by the etiological agent itself. The lesions in the connective tissue of the tail showed much resemblance to those in the interlobular septa of the lungs and contained strong accumulations of serous fluid. The tip of the tail was obviously a good choice; this was confirmed later by many authors and the procedure is still being used today in areas where the disease is still prevalent. Inoculation at other sites of the body such as

  8. Assessing the impact of a movement network on the spatiotemporal spread of infectious diseases.

    PubMed

    Schrödle, Birgit; Held, Leonhard; Rue, Håvard

    2012-09-01

    Linking information on a movement network with space-time data on disease incidence is one of the key challenges in infectious disease epidemiology. In this article, we propose and compare two statistical frameworks for this purpose, namely, parameter-driven (PD) and observation-driven (OD) models. Bayesian inference in PD models is done using integrated nested Laplace approximations, while OD models can be easily fitted with existing software using maximum likelihood. The predictive performance of both formulations is assessed using proper scoring rules. As a case study, the impact of cattle trade on the spatiotemporal spread of Coxiellosis in Swiss cows, 2004-2009, is finally investigated.

  9. The determinants of spread of Ebola virus disease - an evidence from the past outbreak experiences.

    PubMed

    Gałas, Aleksander

    2014-01-01

    The paper summarizes available evidence regarding the determinants of spread of Ebola virus disease, including health care and community related risk factors. It was observed that the level of uncertainty for the estimations is relatively high which may hinder to make some predictions for the future evolution of EVD outbreak. The natural history of EVD has shown that the disease may pose a problem to developed countries and may present a thread to individuals. Although observed modes of transmission mainly include direct contact and contaminated staff, high case fatality ratio and frequent contacts among individuals in developed countries are among determinants which may lead to the development of the EVD outbreak.

  10. 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.

  11. Applications of mathematical modeling in managing the spread of chronic wasting disease (CWD) in wild deer under alternative harvesting scenarios.

    PubMed

    Al-Arydah, M; Croteau, M C; Oraby, T; Smith, R J; Krewski, D

    2016-01-01

    The application of a recently developed mathematical model for predicting the spread of chronic wasting disease (CWD) in wild deer was assessed under different scenarios where harvesting is employed in disease management. A process-based mathematical model for CWD transmission in wild deer populations was recently developed and parameterized by Al-arydah et al. (2011) to provide a scientific basis for understanding the factors that affect spread of CWD and evaluate concomitant disease-control strategies. The impact of gender on CWD transmission was shown to have a significant influence on the spread of the disease in the wild. Our model demonstrates a range of harvesting rates in which CWD is controlled and deer populations survive. However, if harvesting rates are too low, the disease remains endemic for decades. Conversely, the Canadian deer population is eradicated if harvesting rates are excessive. Future investigation includes building the model to assess the spread of CWD under different disease-management scenarios.

  12. 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...

  13. 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.

  14. Host mating system and the spread of a disease-resistant allele in a population

    USGS Publications Warehouse

    DeAngelis, D.L.; Koslow, Jennifer M.; Jiang, J.; Ruan, S.

    2008-01-01

    The model presented here modifies a susceptible-infected (SI) host-pathogen model to determine the influence of mating system on the outcome of a host-pathogen interaction. Both deterministic and stochastic (individual-based) versions of the model were used. This model considers the potential consequences of varying mating systems on the rate of spread of both the pathogen and resistance alleles within the population. We assumed that a single allele for disease resistance was sufficient to confer complete resistance in an individual, and that both homozygote and heterozygote resistant individuals had the same mean birth and death rates. When disease invaded a population with only an initial small fraction of resistant genes, inbreeding (selfing) tended to increase the probability that the disease would soon be eliminated from a small population rather than become endemic, while outcrossing greatly increased the probability that the population would become extinct due to the disease.

  15. 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

  16. 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

  17. Phlebotomine sandflies and the spreading of leishmaniases and other diseases of public health concern.

    PubMed

    Maroli, M; Feliciangeli, M D; Bichaud, L; Charrel, R N; Gradoni, L

    2013-06-01

    Phlebotomine sandflies transmit pathogens that affect humans and animals worldwide. We review the roles of phlebotomines in the spreading of leishmaniases, sandfly fever, summer meningitis, vesicular stomatitis, Chandipura virus encephalitis and Carrión's disease. Among over 800 species of sandfly recorded, 98 are proven or suspected vectors of human leishmaniases; these include 42 Phlebotomus species in the Old World and 56 Lutzomyia species in the New World (all: Diptera: Psychodidae). Based on incrimination criteria, we provide an updated list of proven or suspected vector species by endemic country where data are available. Increases in sandfly diffusion and density resulting from increases in breeding sites and blood sources, and the interruption of vector control activities contribute to the spreading of leishmaniasis in the settings of human migration, deforestation, urbanization and conflict. In addition, climatic changes can be expected to affect the density and dispersion of sandflies. Phlebovirus infections and diseases are present in large areas of the Old World, especially in the Mediterranean subregion, in which virus diversity has proven to be higher than initially suspected. Vesiculovirus diseases are important to livestock and humans in the southeastern U.S.A. and Latin America, and represent emerging human threats in parts of India. Carrión's disease, formerly restricted to regions of elevated altitude in Peru, Ecuador and Colombia, has shown recent expansion to non-endemic areas of the Amazon basin.

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

    PubMed Central

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

    2015-01-01

    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

  19. Spread of infectious diseases in a hyperbolic reaction-diffusion susceptible-infected-removed model

    NASA Astrophysics Data System (ADS)

    Barbera, Elvira; Consolo, Giancarlo; Valenti, Giovanna

    2013-11-01

    A one-dimensional hyperbolic reaction-diffusion model of epidemics is developed to describe the dynamics of diseases spread occurring in an environment where three kinds of individuals mutually interact: the susceptibles, the infectives, and the removed. It is assumed that the disease is transmitted from the infected population to the susceptible one according to a nonlinear convex incidence rate. The model, based upon the framework of extended thermodynamics, removes the unphysical feature of instantaneous diffusive effects, which is typical of parabolic models. Linear stability analyses are performed to study the nature of the equilibrium states against uniform and nonuniform perturbations. Emphasis is given to the occurrence of Hopf and Turing bifurcations, which break the temporal and the spatial symmetry of the system, respectively. The existence of traveling wave solutions connecting two steady states is also discussed. The governing equations are also integrated numerically to validate the analytical results and to characterize the spatiotemporal evolution of diseases.

  20. Duelling timescales of host mixing and disease spread determine invasion of disease in structured populations

    USGS Publications Warehouse

    Cross, P.C.; Lloyd-Smith, J. O.; Johnson, P.L.F.; Getz, W.M.

    2005-01-01

    The epidemic potential of a disease is traditionally assessed using the basic reproductive number, R0. However, in populations with social or spatial structure a chronic disease is more likely to invade than an acute disease with the same R0, because it persists longer within each group and allows for more host movement between groups. Acute diseases ‘perceive’ a more structured host population, and it is more important to consider host population structure in analyses of these diseases. The probability of a pandemic does not arise independently from characteristics of either the host or disease, but rather from the interaction of host movement and disease recovery timescales. The R* statistic, a group-level equivalent of R0, is a better indicator of disease invasion in structured populations than the individual-level R0.

  1. Analysis of Swine Movement in Four Canadian Regions: Network Structure and Implications for Disease Spread.

    PubMed

    Thakur, K K; Revie, C W; Hurnik, D; Poljak, Z; Sanchez, J

    2016-02-01

    Direct and indirect contacts among animal holdings are important in the spread of infectious diseases. The objectives of this study were to describe networks of pig movements and the sharing of trucks used for those movements between swine farms in four Canadian regions using network analysis tools and to obtain contact parameters for infectious disease spread simulation models. Four months of swine movement data from a pilot pig traceability programme were used. Two types of networks were created using three time scales (weekly, monthly and the full study period): one-mode networks of farm-to-farm direct contact representing animal shipments and two-mode networks representing the sharing of trucks between farms. Contact patterns among farms were described by estimating a range of relevant network measures. The overall network neglecting the four regions consisted of 145 farms, which were connected by 261 distinct links. A total of 184 trucks were used to transport 2043 shipments of pigs during the study period. The median in- and out-degree for the overall one-mode network was 1 and ranged from 0 to 26 and 0 to 10, respectively. The overall one-mode network had heterogeneous degree distribution, a high clustering coefficient and shorter average path length than would be expected for randomly generated networks of similar size. On average one truck was shared by four farms in the overall network, or by three farms when considered the monthly and weekly networks. Degree distribution of the two-mode overall network demonstrated characteristics of power-law distribution. For more than 50% of shipments on any given day, the same truck was used for at least one other shipment. Findings from this study are in agreement with previous work, which suggested that swine movement networks exhibit small-world and scale-free topologies. Furthermore, trucks used for the shipment of pigs can play an important role in connecting otherwise unconnected farms and may increase the

  2. Ebola virus disease in southern Sudan: hospital dissemination and intrafamilial spread

    PubMed Central

    Baron, Roy C.; McCormick, Joseph B.; Zubeir, Osman A.

    1983-01-01

    Between 31 July and 6 October 1979, 34 cases of Ebola virus disease (22 of which were fatal) occurred among five families in a rural district of southern Sudan; the disease was introduced into four of the families from a local hospital. Chains of secondary spread within the family units, accounting for 29 cases resulted from direct physical contact with an infected person. Among all persons with such contact in the family setting, those who provided nursing care had a 5.1-fold increased risk of infection, emphasizing the importance of intimate contact in the spread of this disease. The absence of illness among persons who were exposed to cases in confined spaces, but without physical contact, confirmed previous impressions that there is no risk of airborne transmission. While the ecology of Ebola virus is unknown, the presence of anti-Ebola antibodies in the sera of 18% of persons who were unassociated with the outbreak suggests that the region is an endemic focus of Ebola virus activity. PMID:6370486

  3. 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.

  4. 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.

  5. A Lagrangian particle model to predict the airborne spread of foot-and-mouth disease virus

    NASA Astrophysics Data System (ADS)

    Mayer, D.; Reiczigel, J.; Rubel, F.

    Airborne spread of bioaerosols in the boundary layer over a complex terrain is simulated using a Lagrangian particle model, and applied to modelling the airborne spread of foot-and-mouth disease (FMD) virus. Two case studies are made with study domains located in a hilly region in the northwest of the Styrian capital Graz, the second largest town in Austria. Mountainous terrain as well as inhomogeneous and time varying meteorological conditions prevent from application of so far used Gaussian dispersion models, while the proposed model can handle these realistically. In the model, trajectories of several thousands of particles are computed and the distribution of virus concentration near the ground is calculated. This allows to assess risk of infection areas with respect to animal species of interest, such as cattle, swine or sheep. Meteorological input data like wind field and other variables necessary to compute turbulence were taken from the new pre-operational version of the non-hydrostatic numerical weather prediction model LMK ( Lokal-Modell-Kürzestfrist) running at the German weather service DWD ( Deutscher Wetterdienst). The LMK model provides meteorological parameters with a spatial resolution of about 2.8 km. To account for the spatial resolution of 400 m used by the Lagrangian particle model, the initial wind field is interpolated upon the finer grid by a mass consistent interpolation method. Case studies depict a significant influence of local wind systems on the spread of virus. Higher virus concentrations at the upwind side of the hills and marginal concentrations in the lee are well observable, as well as canalization effects by valleys. The study demonstrates that the Lagrangian particle model is an appropriate tool for risk assessment of airborne spread of virus by taking into account the realistic orographic and meteorological conditions.

  6. Fifth Disease (Erythema Infectiosum)

    MedlinePlus

    ... cases, especially in adults and older teens, an attack of fifth disease may be followed by joint swelling or pain, often in the hands, wrists, knees, or ankles. continue Contagiousness A person with parvovirus infection is most contagious before the ...

  7. Sexual identity and practices relating to the spread of sexually transmitted diseases.

    PubMed

    Featherston, W E

    1990-03-01

    All sexually transmitted diseases are behaviorally correlated. A thorough understanding of the behaviors involved in the spread of sexually transmitted disease will increase the physician's ability to suspect, properly identify, and treat the disease. An appreciation of the common sexual behavior in contemporary American society will allow the physician to more effectively address patients' concerns about their sexuality and sexual behavior and identify areas for which further professional counseling is appropriate. Physicians are the most trusted source of health information, often counsel their patients on intimate subjects, and therefore are in a unique position to promote individual behavioral and perceptual changes for limiting the spread of sexually transmitted disease. Physicians must, therefore, be aggressive in taking sexual histories, especially for young, sexually active patients, whether heterosexual, homosexual, or bisexual. Clinicians must deliberately cultivate a comfortable, sympathetic attitude and provide an environment in which a complete and honest sexual practices history will freely flow. Once the patients at risk for STDs are identified, the physician should attempt to counsel them to reduce their risk through safer sexual practices. If little office time is available for these sensitive educational issues, then the physician should identify individuals within the office or appropriate programs in the community for referral. Representative data on the sexual behavior of all Americans will be relevant not only to the AIDS crisis but also to other national sex-related problems such as the growing incidence of chlamydia, other sexually transmitted diseases, and the costly multigenerational impact of epidemic teenage pregnancy. Comprehensive, well-designed studies of contemporary sexual behavior are needed now.

  8. Network analysis of swine shipments in Ontario, Canada, to support disease spread modelling and risk-based disease management.

    PubMed

    Dorjee, S; Revie, C W; Poljak, Z; McNab, W B; Sanchez, J

    2013-10-01

    Understanding contact networks are important for modelling and managing the spread and control of communicable diseases in populations. This study characterizes the swine shipment network of a multi-site production system in southwestern Ontario, Canada. Data were extracted from a company's database listing swine shipments among 251 swine farms, including 20 sow, 69 nursery and 162 finishing farms, for the 2-year period of 2006 to 2007. Several network metrics were generated. The number of shipments per week between pairs of farms ranged from 1 to 6. The medians (and ranges) of out-degree were: sow 6 (1-21), nursery 8 (0-25), and finishing 0 (0-4), over the entire 2-year study period. Corresponding estimates for in-degree of nursery and finishing farms were 3 (0-9) and 3 (0-12) respectively. Outgoing and incoming infection chains (OIC and IIC), were also measured. The medians (ranges) of the monthly OIC and IIC were 0 (0-8) and 0 (0-6), respectively, with very similar measures observed for 2-week intervals. Nursery farms exhibited high measures of centrality. This indicates that they pose greater risks of disease spread in the network. Therefore, they should be given a high priority for disease prevention and control measures affecting all age groups alike. The network demonstrated scale-free and small-world topologies as observed in other livestock shipment studies. This heterogeneity in contacts among farm types and network topologies should be incorporated in simulation models to improve their validity. In conclusion, this study provided useful epidemiological information and parameters for the control and modelling of disease spread among swine farms, for the first time from Ontario, Canada.

  9. Computer animations stimulate contagious yawning in chimpanzees.

    PubMed

    Campbell, Matthew W; Carter, J Devyn; Proctor, Darby; Eisenberg, Michelle L; de Waal, Frans B M

    2009-12-07

    People empathize with fictional displays of behaviour, including those of cartoons and computer animations, even though the stimuli are obviously artificial. However, the extent to which other animals also may respond empathetically to animations has yet to be determined. Animations provide a potentially useful tool for exploring non-human behaviour, cognition and empathy because computer-generated stimuli offer complete control over variables and the ability to program stimuli that could not be captured on video. Establishing computer animations as a viable tool requires that non-human subjects identify with and respond to animations in a way similar to the way they do to images of actual conspecifics. Contagious yawning has been linked to empathy and poses a good test of involuntary identification and motor mimicry. We presented 24 chimpanzees with three-dimensional computer-animated chimpanzees yawning or displaying control mouth movements. The apes yawned significantly more in response to the yawn animations than to the controls, implying identification with the animations. These results support the phenomenon of contagious yawning in chimpanzees and suggest an empathic response to animations. Understanding how chimpanzees connect with animations, to both empathize and imitate, may help us to understand how humans do the same.

  10. Evidence for emergence of an amphibian iridoviral disease because of human-enhanced spread.

    PubMed

    Jancovich, J K; Davidson, E W; Parameswaran, N; Mao, J; Chinchar, V G; Collins, J P; Jacobs, B L; Storfer, A

    2005-01-01

    Our understanding of origins and spread of emerging infectious diseases has increased dramatically because of recent applications of phylogenetic theory. Iridoviruses are emerging pathogens that cause global amphibian epizootics, including tiger salamander (Ambystoma tigrinum) die-offs throughout western North America. To explain phylogeographical relationships and potential causes for emergence of western North American salamander iridovirus strains, we sequenced major capsid protein and DNA methyltransferase genes, as well as two noncoding regions from 18 geographically widespread isolates. Phylogenetic analyses of sequence data from the capsid protein gene showed shallow genetic divergence (< 1%) among salamander iridovirus strains and monophyly relative to available fish, reptile, and other amphibian iridovirus strains from the genus Ranavirus, suggesting a single introduction and radiation. Analysis of capsid protein sequences also provided support for a closer relationship of tiger salamander virus strains to those isolated from sport fish (e.g. rainbow trout) than other amphibian isolates. Despite monophyly based on capsid protein sequences, there was low genetic divergence among all strains (< 1.1%) based on a supergene analysis of the capsid protein and the two noncoding regions. These analyses also showed polyphyly of strains from Arizona and Colorado, suggesting recent spread. Nested clade analyses indicated both range expansion and long-distance colonization in clades containing virus strains isolated from bait salamanders and the Indiana University axolotl (Ambystoma mexicanum) colony. Human enhancement of viral movement is a mechanism consistent with these results. These findings suggest North American salamander ranaviruses cause emerging disease, as evidenced by apparent recent spread over a broad geographical area.

  11. Influence of network dynamics on the spread of sexually transmitted diseases

    PubMed Central

    Risau-Gusman, Sebastián

    2012-01-01

    Network epidemiology often assumes that the relationships defining the social network of a population are static. The dynamics of relationships is only taken indirectly into account by assuming that the relevant information to study epidemic spread is encoded in the network obtained, by considering numbers of partners accumulated over periods of time roughly proportional to the infectious period of the disease. On the other hand, models explicitly including social dynamics are often too schematic to provide a reasonable representation of a real population, or so detailed that no general conclusions can be drawn from them. Here, we present a model of social dynamics that is general enough so its parameters can be obtained by fitting data from surveys about sexual behaviour, but that can still be studied analytically, using mean-field techniques. This allows us to obtain some general results about epidemic spreading. We show that using accumulated network data to estimate the static epidemic threshold lead to a significant underestimation of that threshold. We also show that, for a dynamic network, the relative epidemic threshold is an increasing function of the infectious period of the disease, implying that the static value is a lower bound to the real threshold. A practical example is given of how to apply the model to the study of a real population. PMID:22112655

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  13. Spreading of tau pathology in Alzheimer's disease by cell-to-cell transmission.

    PubMed

    Mohamed, Nguyen-Vi; Herrou, Thibaut; Plouffe, Vanessa; Piperno, Nicolas; Leclerc, Nicole

    2013-06-01

    It is well documented that neurofibrillary tangles composed of aggregated tau protein propagate in a predictable pattern in Alzheimer's disease (AD). The mechanisms underlying the propagation of tau pathology are still poorly understood. Recent studies have provided solid data demonstrating that in several neurodegenerative diseases including AD, the spreading of misfolded protein aggregates in the brain would result from prion-like cell-to-cell transmission. Consistent with this new concept, recent studies have reported that human tau can be released in the extracellular space by an active process of secretion, and can be endocytosed both in vitro and in vivo. Most importantly, it was reported that the spreading of tau pathology was observed along synaptically connected circuits in a transgenic mouse model where human tau overexpression was restricted in the entorhinal cortex. This indicates that secretion of tau by presynaptic neurons and its uptake by postsynaptic neurons could be the sequential events leading to the propagation of tau pathology in the brain.

  14. An integrated model to predict the atmospheric spread of foot-and-mouth disease virus.

    PubMed Central

    Sørensen, J. H.; Mackay, D. K.; Jensen, C. O.; Donaldson, A. I.

    2000-01-01

    The application of a computer model called Rimpuff for simulating the airborne spread of foot-and-mouth disease (FMD) is described. Rimpuff is more sophisticated and accurate than other FMD simulation models previously described. It can be run on a desktop computer and performs analyses very quickly. It can be linked to a geographical information system and so the information generated can be integrated with geographical and demographical data for display in a format that can be easily assimilated and transmitted electronically. The system was validated using historical data from outbreaks of FMD in France and the UK in 1981, and from Denmark and the former German Democratic Republic (GDR) in 1982. A very good fit was obtained between the direction of the plumes of virus simulated by the model and the spread of disease from France to the UK in 1981. Although cattle in the UK were infected during the episode, the concentrations of airborne virus in the plumes simulated by the model were beneath the infectivity threshold for cattle. It was concluded from the analysis that the number of pigs infected in France, and therefore the source concentration of airborne virus, was probably much higher than was recorded at the time of the outbreaks. Analysis of the Denmark/GDR episode pointed to the possibility that the source of virus for the 1982 epidemic in Denmark could have been one or more unreported outbreaks involving pigs in the former GDR. PMID:10982082

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

    PubMed Central

    Held, Leonhard

    2017-01-01

    Summary Routine public health surveillance of notifiable infectious diseases gives rise to weekly counts of reported cases—possibly stratified by region and/or age group. We investigate how an age-structured social contact matrix can be incorporated into a spatio-temporal endemic–epidemic model for infectious disease counts. To illustrate the approach, we analyze the spread of norovirus gastroenteritis over six age groups within the 12 districts of Berlin, 2011–2015, using contact data from the POLYMOD study. The proposed age-structured model outperforms alternative scenarios with homogeneous or no mixing between age groups. An extended contact model suggests a power transformation of the survey-based contact matrix toward more within-group transmission. PMID:28025182

  16. Spread of a disease and its effect on population dynamics in an eco-epidemiological system

    NASA Astrophysics Data System (ADS)

    Upadhyay, Ranjit Kumar; Roy, Parimita

    2014-12-01

    In this paper, an eco-epidemiological model with simple law of mass action and modified Holling type II functional response has been proposed and analyzed to understand how a disease may spread among natural populations. The proposed model is a modification of the model presented by Upadhyay et al. (2008) [1]. Existence of the equilibria and their stability analysis (linear and nonlinear) has been studied. The dynamical transitions in the model have been studied by identifying the existence of backward Hopf-bifurcations and demonstrated the period-doubling route to chaos when the death rate of predator (μ1) and the growth rate of susceptible prey population (r) are treated as bifurcation parameters. Our studies show that the system exhibits deterministic chaos when some control parameters attain their critical values. Chaotic dynamics is depicted using the 2D parameter scans and bifurcation analysis. Possible implications of the results for disease eradication or its control are discussed.

  17. The Impact of Farmers’ Strategic Behavior on the Spread of Animal Infectious Diseases

    PubMed Central

    Hammitt, James K.; Thomas, Alban; Raboisson, Didier

    2016-01-01

    One of the main strategies to control the spread of infectious animal diseases is the implementation of movement restrictions. This paper shows a loss in efficiency of the movement restriction policy (MRP) when behavioral responses of farmers are taken into account. Incorporating the strategic behavior of farmers in an epidemiologic model reveals that the MRP can trigger premature animal sales by farms at high risk of becoming infected that significantly reduce the efficacy of the policy. The results are validated in a parameterized network via Monte Carlo simulations and measures to mitigate the loss of efficiency of the MRP are discussed. Financial aid to farmers can be justified by public health concerns, not only for equity. This paper contributes to developing an interdisciplinary analytical framework regarding the expansion of infectious diseases combining economic and epidemiologic dimensions. PMID:27300368

  18. Teen Violence Can Be Contagious, Study Contends

    MedlinePlus

    ... were far more likely to engage in a violent act if a friend had also done so. ... shows how important social relationships are to spreading violent behavior, just like they are for spreading many ...

  19. A Simple Model to Rank Shellfish Farming Areas Based on the Risk of Disease Introduction and Spread.

    PubMed

    Thrush, M A; Pearce, F M; Gubbins, M J; Oidtmann, B C; Peeler, E J

    2016-03-09

    The European Union Council Directive 2006/88/EC requires that risk-based surveillance (RBS) for listed aquatic animal diseases is applied to all aquaculture production businesses. The principle behind this is the efficient use of resources directed towards high-risk farm categories, animal types and geographic areas. To achieve this requirement, fish and shellfish farms must be ranked according to their risk of disease introduction and spread. We present a method to risk rank shellfish farming areas based on the risk of disease introduction and spread and demonstrate how the approach was applied in 45 shellfish farming areas in England and Wales. Ten parameters were used to inform the risk model, which were grouped into four risk themes based on related pathways for transmission of pathogens: (i) live animal movement, (ii) transmission via water, (iii) short distance mechanical spread (birds) and (iv) long distance mechanical spread (vessels). Weights (informed by expert knowledge) were applied both to individual parameters and to risk themes for introduction and spread to reflect their relative importance. A spreadsheet model was developed to determine quantitative scores for the risk of pathogen introduction and risk of pathogen spread for each shellfish farming area. These scores were used to independently rank areas for risk of introduction and for risk of spread. Thresholds were set to establish risk categories (low, medium and high) for introduction and spread based on risk scores. Risk categories for introduction and spread for each area were combined to provide overall risk categories to inform a risk-based surveillance programme directed at the area level. Applying the combined risk category designation framework for risk of introduction and spread suggested by European Commission guidance for risk-based surveillance, 4, 10 and 31 areas were classified as high, medium and low risk, respectively.

  20. Social Presence Diminishes Contagious Yawning in the Laboratory

    PubMed Central

    Gallup, Andrew; Church, Allyson M.; Miller, Heather; Risko, Evan F.; Kingstone, Alan

    2016-01-01

    Contagious yawning may be a useful measure of social psychological functioning, and thus it is important to evaluate the variables influencing its expression in laboratory settings. Previous research has documented that humans yawn less frequently in crowded environments and when under direct observation, but the impact of social presence on contagious yawning remains unknown. Here we present the first study to systematically alter the degree of social presence experienced by participants in the laboratory to determine its effect on contagious yawning frequency. Our results demonstrate that both implied and actual social presence significantly diminish yawn contagion in comparison to a control condition, indicating a key social component to contagious yawning. These findings provide a framework for pursuing additional research investigating the social factors influencing contagious yawning, while also offering applications for measuring this response in laboratory settings. PMID:27112374

  1. 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.

  2. Transmission of Chronic Wasting Disease in Wisconsin White-Tailed Deer: Implications for Disease Spread and Management

    PubMed Central

    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

  3. Simulating the spread of malaria using a generic transmission model for mosquito-borne infectious diseases

    NASA Astrophysics Data System (ADS)

    Kon, Cynthia Mui Lian; Labadin, Jane

    2016-06-01

    Malaria is a critical infection caused by parasites which are spread to humans through mosquito bites. Approximately half of the world's population is in peril of getting infected by malaria. Mosquito-borne diseases have a standard behavior where they are transmitted in the same manner, only through vector mosquito. Taking this into account, a generic spatial-temporal model for transmission of multiple mosquito-borne diseases had been formulated. Our interest is to reproduce the actual cases of different mosquito-borne diseases using the generic model and then predict future cases so as to improve control and target measures competently. In this paper, we utilize notified weekly malaria cases in four districts in Sarawak, Malaysia, namely Kapit, Song, Belaga and Marudi. The actual cases for 36 weeks, which is from week 39 in 2012 to week 22 in 2013, are compared with simulations of the generic spatial-temporal transmission mosquito-borne diseases model. We observe that the simulation results display corresponding result to the actual malaria cases in the four districts.

  4. The dynamics of spreading bacterial diseases and ilnesses caused by helminthosis in Adjara Autonomous Republic 2011.

    PubMed

    Lomtatidze, N; Chachnelidze, R; Chkaidze, M

    2013-01-01

    According to the data of past few years it has been determined that the general incidence and the prevalence of the bacterial and helminthosis diseases have increased. Epidemic Supervision has registered a slight increase of such diseases in data of 2011. Taking into consideration this fact, this research is quite important for the region of Adjara. The aim of our research is to study the dynamics of spreading some bacterial and helminthosis diseases in Adjara Autonomous Republic. In particular, the diseases caused by different bacterias of leptospira family - leptospirosis and illnesses caused by helminthosis - ascariasis, enterobiasis and trichocephalosis. according to the reseaches held it has been determined that there have been several cases of leptospirosis registered in Adjara. Specifically, 10 cases in 2008, 6 in 2009, 30 in 2010 and 31 cases in 2011 out of which 10 of the cases where laboratorily claimed. There were cases of ascariasis, enterobiasis and trichocephalosis. According to data, there are 5 times less cases of trichocephalosis than of ascariasis. As for enterobiasis, it's less than ascariasis (the difference is 205 cases). In therms of the aging, all the cases occur more frequently in the group of children below the age of 14.

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

    PubMed

    Robinson, Katy; Cohen, Ted; Colijn, Caroline

    2012-03-01

    Sexually transmitted pathogens persist in populations despite the availability of biomedical interventions and knowledge of behavioural changes that would reduce individual-level risk. While behavioural risk factors are shared between many sexually transmitted infections, the prevalence of these diseases across different risk groups varies. Understanding this heterogeneity and identifying better control strategies depends on an improved understanding of the complex social contact networks over which pathogens spread. To date, most efforts to study the impact of sexual network structure on disease dynamics have focused on static networks. However, the interaction between the dynamics of partnership formation and dissolution and the dynamics of transmission plays a role, both in restricting the effective network accessible to the pathogen, and in modulating the transmission dynamics. We present a simple method to simulate dynamical networks of sexual partnerships. We inform the model using survey data on sexual attitudes and lifestyles, and investigate how the duration of infectiousness changes the effective contact network over which disease may spread. We then simulate several control strategies: screening, vaccination and behavioural interventions. Previous theory and research has advanced the importance of core groups for spread and control of STD. Our work is consistent with the importance of core groups, but extends this idea to consider how the duration of infectiousness associated with a particular pathogen interacts with host behaviours to define these high risk subpopulations. Characteristics of the parts of the network accessible to the pathogen, which represent the network structure of sexual contacts from the "point of view" of the pathogen, are substantially different from those of the network as a whole. The pathogen itself plays an important role in determining this effective network structure; specifically, we find that if the pathogen's duration of

  6. Controlling the geographical spread of infectious disease: plague in Italy, 1347-1851.

    PubMed

    Cliff, Andrew D; Smallman-Raynor, Matthew R; Stevens, Peta M

    2009-01-01

    After the establishment of the first quarantine station in the Republic of Ragusa (modern-day Dubrovnik) in 1377, the states and principalities of Italy developed a sophisticated system of defensive quarantine in an attempt to protect themselves from the ravages of plague. Using largely unknown and unseen historical maps, this paper reconstructs the extent and operation of the system used. It is shown that a cordon sanitaire existed around the coast of Italy for several centuries, consisting of three elements: (i) an outer defensive ring of armed sailing boats in the Mediterranean and the Adriatic, (ii) a middle coastal ring of forts and observation towers, and (iii) an inner defensive ring of land-based cavalry. The principles established, although not especially successful at the time against a disease of (then) unknown aetiology, are still used today in attempts to control the spread of infections of animal and human populations.

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

    PubMed

    Maccari, Marta; 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. Epidemic spread of influenza viruses: The impact of transient populations on disease dynamics.

    PubMed

    Ríos-Soto, Karen R; Song, Baojun; Castillo-Chavez, Carlos

    2011-01-01

    The recent H1N1 ("swine flu") pandemic and recent H5N1 ("avian flu") outbreaks have brought increased attention to the study of the role of animal populations as reservoirs for pathogens that could invade human populations. It is believed that pigs acquired flu strains from birds and humans, acting as a mixing vessel in generating new influenza viruses. Assessing the role of animal reservoirs, particularly reservoirs involving highly mobile populations (like migratory birds), on disease dispersal and persistence is of interests to a wide range of researchers including public health experts and evolutionary biologists. This paper studies the interactions between transient and resident bird populations and their role on dispersal and persistence. A metapopulation framework based on a system of nonlinear ordinary differential equations is used to study the transmission dynamics and control of avian diseases. Simplified versions of mathematical models involving a limited number of migratory and resident bird populations are analyzed. Epidemiological time scales and singular perturbation methods are used to reduce the dimensionality of the model. Our results show that mixing of bird populations (involving residents and migratory birds) play an important role on the patterns of disease spread.

  13. Representative Contact Diaries for Modeling the Spread of Infectious Diseases in Taiwan

    PubMed Central

    Fu, Yang-chih; Wang, Da-Wei; Chuang, Jen-Hsiang

    2012-01-01

    Recent studies of infectious diseases have attempted to construct more realistic parameters of interpersonal contact patterns from diary-approach surveys. To ensure that such diary-based contact patterns provide accurate baseline data for policy implementation in densely populated Taiwan, we collected contact diaries from a national sample, using 3-stage systematic probability sampling and rigorous in-person interviews. A representative sample of 1,943 contact diaries recorded a total of 24,265 wide-range, face-to-face interpersonal contacts during a 24-hour period. Nearly 70% of the contacts occurred outside of respondents' households. The most active age group was schoolchildren (ages 5–14), who averaged around 16–18 daily contacts, about 2–3 times as many as the least active age groups. We show how such parameters of contact patterns help modify a sophisticated national simulation system that has been used for years to model the spread of pandemic diseases in Taiwan. Based on such actual and representative data that enable researchers to infer findings to the whole population, our analyses aim to facilitate implementing more appropriate and effective strategies for controlling an emerging or pandemic disease infection. PMID:23056193

  14. Identification and phylogenetic analysis of contagious ecthyma virus from camels (Camelus dromedarius) in Iran.

    PubMed

    Oryan, Ahmad; Mosadeghhesari, Mahboobe; Zibaee, Saeed; Mohammadi, Ali

    2017-03-24

    Contagious ecthyma is a highly contagious disease affecting domestic and wild ruminants such as sheep, goats and camels. The identification and characterisation of a parapoxvirus (PPV) infecting camels is described here. The virus was detected in dromedary camels (Camelus dromedarius) from Kerman and Shiraz in Iran. PPV-specific amplification by polymerase chain reaction (PCR) further confirmed that the disease was associated with PPV infection. Phylogenetic analysis of ORF011 (B2L) gene sequences showed 99.79% and 82.13% similarity of the PPV identified in this study with the Jodhpur isolate and the bovine papular stomatitis virus (BPSV) isolates (CE41), respectively. Moreover, phylogenetic analysis of the ORF045 gene indicated that the Shiraz sample was in all probability closely related to VR634 and to F00.120R and PCPV776. In conclusion, the results suggest that camel PPV (CPPV) is a likely cause of contagious ecthyma in dromedary camels in Iran.

  15. 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.

  16. Multivariate analysis of traditional pig management practices and their potential impact on the spread of infectious diseases in Corsica.

    PubMed

    Relun, A; Charrier, F; Trabucco, B; Maestrini, O; Molia, S; Chavernac, D; Grosbois, V; Casabianca, F; Etter, E; Jori, F

    2015-10-01

    Corsica is a French Mediterranean island with traditional extensive pig farming oriented towards the production of high quality cured meat products. The increasing success of these cured products in continental Europe has triggered the development and organisation of an extensive pig farming industry. However, these pig farming practices have seldom been described and analysed to understand the potential risk of introduction and spread of infectious diseases. We conducted a cross-sectional study in Corsica in 2013 to characterise the main pig management practices and to identify groups of farms with similar practices and therefore homogeneous risk of introduction and spread of infectious diseases. We interviewed 68 pig farmers and investigated different farm management practices which could lead to contact between herds, such as trading animals, sharing pastures, feed and reproduction management (direct contacts), slaughtering and carcass waste management, and contacts with people and vehicles (indirect contacts). The practices were described and the farms grouped by multiple factor and hierarchical clustering analyses. Results revealed interesting patterns in the introduction and spread of infectious disease, such as the seasonality of pig production, the potential local spread of diseases in pastures due to the presence of free-ranging boars, carcasses, and animal waste. Multivariate analyses identified four groups of farms with different levels of risk of the spread of infectious disease, illustrating changes in farmers' customs from free-range uncontrolled farming systems to more controlled systems aimed at the production of high quality pork products. These results will be useful to more realistically simulate the spread of infectious diseases among Corsican pig farms and highlight the need for awareness raising campaigns among the stakeholders to reduce risky practices.

  17. 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.

  18. The Contribution of α-Synuclein Spreading to Parkinson's Disease Synaptopathy

    PubMed Central

    Faustini, Gaia; Missale, Cristina; Pizzi, Marina; Spano, PierFranco

    2017-01-01

    Synaptopathies are diseases with synapse defects as shared pathogenic features, encompassing neurodegenerative disorders such as Parkinson's disease (PD). In sporadic PD, the most common age-related neurodegenerative movement disorder, nigrostriatal dopaminergic deficits are responsible for the onset of motor symptoms that have been related to α-synuclein deposition at synaptic sites. Indeed, α-synuclein accumulation can impair synaptic dopamine release and induces the death of nigrostriatal neurons. While in physiological conditions the protein can interact with and modulate synaptic vesicle proteins and membranes, numerous experimental evidences have confirmed that its pathological aggregation can compromise correct neuronal functioning. In addition, recent findings indicate that α-synuclein pathology spreads into the brain and can affect the peripheral autonomic and somatic nervous system. Indeed, monomeric, oligomeric, and fibrillary α-synuclein can move from cell to cell and can trigger the aggregation of the endogenous protein in recipient neurons. This novel “prion-like” behavior could further contribute to synaptic failure in PD and other synucleinopathies. This review describes the major findings supporting the occurrence of α-synuclein pathology propagation in PD and discusses how this phenomenon could induce or contribute to synaptic injury and degeneration. PMID:28133550

  19. Epidemiologic indicators associated with within-farm spread of Johne's disease in dairy farms in Japan.

    PubMed

    Kobayashi, Sota; Tsutsui, Toshiyuki; Yamamoto, Takehisa; Nishiguchi, Akiko

    2007-12-01

    Epidemiologic indicators associated with within-farm infection of Johne's disease in dairy farms in Japan were determined through a nationwide investigation of infected farms. We assumed that subsequent detection of the disease within one year after the first detection could represent the occurrence of within-farm spread occurring before the first detection. Of 594 infected farms, 158 farms (27%) had at least one additional detection. Logistic regression analysis using epidemiologic information obtained from infected farms at the time of the first detection revealed three epidemiologic indicators associated with subsequent detection. Farms at which the first cases included cattle with clinical signs were 3.8 (95% confidence interval: 2.2, 6.8) times more likely to have additional detections than those with cattle without clinical signs. Similarly, farms where two or more cattle were detected at the time of first detection and where cattle were held in a loose housing system were 2.8 (95% CI: 1.8, 4.5) and 2.0 (95% CI: 1.1, 3.6) times more likely to have additional detections than those where only one animal was detected and a tied-up housing system was used, respectively. These epidemiologic indicators are likely important determinants in the selection of farms requiring more intensive on-farm control measures.

  20. Avian influenza shedding patterns in waterfowl: implications for surveillance, environmental transmission, and disease spread

    USGS Publications Warehouse

    Viviane Henaux,; Samuel, Michael 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 (10–11.5 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 HPAI outbreaks. 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 (in particular, 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 HPAI shedding patterns over time provide essential information to parameterize environmental transmission and virus spread in predictive

  1. Experimental evidence of contagious yawning in budgerigars (Melopsittacus undulatus).

    PubMed

    Gallup, Andrew C; Swartwood, Lexington; Militello, Janine; Sackett, Serena

    2015-09-01

    Experimental evidence of contagious yawning has only been documented in four mammalian species. Here, we report the results from two separate experimental studies designed to investigate the presence of contagious yawning in a social parrot, the budgerigar (Melopsittacus undulatus). In Study 1, birds were paired in adjacent cages with and without visual barriers, and the temporal association of yawning was assessed between visual conditions. In Study 2, the same birds were exposed to video stimuli of both conspecific yawns and control behavior, and yawning frequency was compared between conditions. Results from both studies demonstrate that yawning is contagious. To date, this is the first experimental evidence of contagious yawning in a non-mammalian species. We propose that future research could use budgerigars to explore questions related to basic forms of empathic processing.

  2. The Risk of Disease to Great Apes: Simulating Disease Spread in Orang-Utan (Pongo pygmaeus wurmbii) and Chimpanzee (Pan troglodytes schweinfurthii) Association Networks

    PubMed Central

    Carne, Charlotte; Semple, Stuart; Morrogh-Bernard, Helen; Zuberbühler, Klaus; Lehmann, Julia

    2014-01-01

    All great ape species are endangered, and infectious diseases are thought to pose a particular threat to their survival. As great ape species vary substantially in social organisation and gregariousness, there are likely to be differences in susceptibility to disease types and spread. Understanding the relation between social variables and disease is therefore crucial for implementing effective conservation measures. Here, we simulate the transmission of a range of diseases in a population of orang-utans in Sabangau Forest (Central Kalimantan) and a community of chimpanzees in Budongo Forest (Uganda), by systematically varying transmission likelihood and probability of subsequent recovery. Both species have fission-fusion social systems, but differ considerably in their level of gregariousness. We used long-term behavioural data to create networks of association patterns on which the spread of different diseases was simulated. We found that chimpanzees were generally far more susceptible to the spread of diseases than orang-utans. When simulating different diseases that varied widely in their probability of transmission and recovery, it was found that the chimpanzee community was widely and strongly affected, while in orang-utans even highly infectious diseases had limited spread. Furthermore, when comparing the observed association network with a mean-field network (equal contact probability between group members), we found no major difference in simulated disease spread, suggesting that patterns of social bonding in orang-utans are not an important determinant of susceptibility to disease. In chimpanzees, the predicted size of the epidemic was smaller on the actual association network than on the mean-field network, indicating that patterns of social bonding have important effects on susceptibility to disease. We conclude that social networks are a potentially powerful tool to model the risk of disease transmission in great apes, and that chimpanzees are

  3. The risk of disease to great apes: simulating disease spread in orang-utan (Pongo pygmaeus wurmbii) and chimpanzee (Pan troglodytes schweinfurthii) association networks.

    PubMed

    Carne, Charlotte; Semple, Stuart; Morrogh-Bernard, Helen; Zuberbühler, Klaus; Lehmann, Julia

    2014-01-01

    All great ape species are endangered, and infectious diseases are thought to pose a particular threat to their survival. As great ape species vary substantially in social organisation and gregariousness, there are likely to be differences in susceptibility to disease types and spread. Understanding the relation between social variables and disease is therefore crucial for implementing effective conservation measures. Here, we simulate the transmission of a range of diseases in a population of orang-utans in Sabangau Forest (Central Kalimantan) and a community of chimpanzees in Budongo Forest (Uganda), by systematically varying transmission likelihood and probability of subsequent recovery. Both species have fission-fusion social systems, but differ considerably in their level of gregariousness. We used long-term behavioural data to create networks of association patterns on which the spread of different diseases was simulated. We found that chimpanzees were generally far more susceptible to the spread of diseases than orang-utans. When simulating different diseases that varied widely in their probability of transmission and recovery, it was found that the chimpanzee community was widely and strongly affected, while in orang-utans even highly infectious diseases had limited spread. Furthermore, when comparing the observed association network with a mean-field network (equal contact probability between group members), we found no major difference in simulated disease spread, suggesting that patterns of social bonding in orang-utans are not an important determinant of susceptibility to disease. In chimpanzees, the predicted size of the epidemic was smaller on the actual association network than on the mean-field network, indicating that patterns of social bonding have important effects on susceptibility to disease. We conclude that social networks are a potentially powerful tool to model the risk of disease transmission in great apes, and that chimpanzees are

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

    MedlinePlus

    ... are spread through all types of sex — oral, anal, or vaginal. You can help protect yourself against ... MD Date reviewed: June 2014 For Teens For Kids For Parents MORE ON THIS TOPIC Flu Center ...

  5. Smell facilitates auditory contagious yawning in stranger rats.

    PubMed

    Moyaho, Alejandro; Rivas-Zamudio, Xaman; Ugarte, Araceli; Eguibar, José R; Valencia, Jaime

    2015-01-01

    Most vertebrates yawn in situations ranging from relaxation to tension, but only humans and other primate species that show mental state attribution skills have been convincingly shown to display yawn contagion. Whether complex forms of empathy are necessary for yawn contagion to occur is still unclear. As empathy is a phylogenetically continuous trait, simple forms of empathy, such as emotional contagion, might be sufficient for non-primate species to show contagious yawning. In this study, we exposed pairs of male rats, which were selected for high yawning, with each other through a perforated wall and found that olfactory cues stimulated yawning, whereas visual cues inhibited it. Unexpectedly, cage-mate rats failed to show yawn contagion, although they did show correlated emotional reactivity. In contrast, stranger rats showed auditory contagious yawning and greater rates of smell-facilitated auditory contagious yawning, although they did not show correlated emotional reactivity. Strikingly, they did not show contagious yawning to rats from a low-yawning strain. These findings indicate that contagious yawning may be a widespread trait amongst vertebrates and that mechanisms other than empathy may be involved. We suggest that a communicatory function of yawning may be the mechanism responsible for yawn contagion in rats, as contagiousness was strain-specific and increased with olfactory cues, which are involved in mutual recognition.

  6. 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.

  7. Heterosexual relationships and condom-use in the spread of sexually transmitted diseases to women.

    PubMed

    Evans, B A; Kell, P D; Bond, R A; MacRae, K D

    1995-10-01

    The authors investigated the effect of patient-defined non-regular heterosexual relationships upon the incidence of sexually transmitted diseases (STD) and other genital infections in women and the role of condom use in preventing their spread. Findings are based upon responses to a 1992 sexual behavior questionnaire among 938 consecutive newly attending women presenting at a genitourinary medicine clinic in West London for screening and diagnosis. It was found that women who reported non-regular sex partners were more likely to be single, White, have had coitarche before age 17 years and many more sex partners both during the last year and in their lifetime, and were more likely to practice fellatio, anal sex, and smoke cigarettes. The incidence of STDs and other genital infections was no higher in this group than among women who did not have non-regular partners. Increasing condom use with regular partners correlated with decreasing incidence of gonorrhea, chlamydial infection, and trichomoniasis, but increasing condom use with non-regular partners did not show a similar trend. The authors conclude that regular heterosexual partners play the major role in transmitting bacterial STDs to women.

  8. 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

  9. [The formation and spread of MRSA strains in patients with pyoinflammatory diseases].

    PubMed

    Gasretova, T D; Sin'kova, O N; Charseeva, G G; Mironov, A Iu

    2013-04-01

    The article considers the results of study of formation and spread of MRSA in patients with suppurative focuses of stafillococus ethiology after application of antibacterial therapy. The antibacterial therapy applied to these patients used one of the following pharmaceuticals--cefazolin, lincomycin, gentamicin, oxampicin, ciprofloxacin, ofloxacin. All the strains of S. aureus ssp. aureus isolated from patients were tested on MRSA. Their phagovars were detected using international kit of phages for grouping of S. aureus ssp. aureus. The comparison of data received after analysis of resistance to oxacillin of strains and their phages isolated at the onset of disease and after applied treatment was carried out. The study established that against the background of applied antibacterial therapy in 10.7% of patients, MRSA formed and in 15.4% of patients, the change of initial strains of S. aureus ssp. aureus by MRSA strains of other phages groups was established. The presented results testified the need of obligatory testing of strains isolated from patients with staphylococcus infection on antibiotics resistance. The application of antibacterial therapy and its correction taking in account the laboratory data on antibiotics resistance and strict following the sanitary hygienic standards.

  10. Trichothecene-Genotypes Play a Role in Fusarium Head Blight Disease Spread and Trichothecene Accumulation in Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the current study, we evaluated the impact of the observed North American evolutionary shift in the Fusarium graminearum complex on disease spread, kernel damage, and trichothecene accumulation in resistant and susceptible wheat genotypes. Four inocula were prepared using composites of F. gramin...

  11. 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

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Procedures recommended to prevent the... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... semen to prevent fecal contamination. If fecal material is present, it should be removed before...

  12. 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

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Procedures recommended to prevent the... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... semen to prevent fecal contamination. If fecal material is present, it should be removed before...

  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

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Procedures recommended to prevent the... recommended to prevent the spread of disease by artificial insemination of turkeys. (a) The vehicle... semen to prevent fecal contamination. If fecal material is present, it should be removed before...

  14. 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

  15. Reconstructing the emergence of a lethal infectious disease of wildlife supports a key role for spread through translocations by humans

    PubMed Central

    Cunningham, Andrew A.; Langton, Tom E. S.

    2016-01-01

    There have been few reconstructions of wildlife disease emergences, despite their extensive impact on biodiversity and human health. This is in large part attributable to the lack of structured and robust spatio-temporal datasets. We overcame logistical problems of obtaining suitable information by using data from a citizen science project and formulating spatio-temporal models of the spread of a wildlife pathogen (genus Ranavirus, infecting amphibians). We evaluated three main hypotheses for the rapid increase in disease reports in the UK: that outbreaks were being reported more frequently, that climate change had altered the interaction between hosts and a previously widespread pathogen, and that disease was emerging due to spatial spread of a novel pathogen. Our analysis characterized localized spread from nearby ponds, consistent with amphibian dispersal, but also revealed a highly significant trend for elevated rates of additional outbreaks in localities with higher human population density—pointing to human activities in also spreading the virus. Phylogenetic analyses of pathogen genomes support the inference of at least two independent introductions into the UK. Together these results point strongly to humans repeatedly translocating ranaviruses into the UK from other countries and between UK ponds, and therefore suggest potential control measures. PMID:27683363

  16. Appearance and spread of diseases among bivalve molluscs in the northern hemisphere in relation to international trade.

    PubMed

    Renault, T

    1996-06-01

    Bivalve mollusc culture is a well-developed marine aquaculture activity in many countries around the world, notably in the northern hemisphere. During the development of this activity, numerous countries have been confronted with infectious diseases of varying severity and duration. Research has been conducted to determine the aetiology, epidemiology and control measures for these epizootics. Major epizootics in bivalve molluscs have been caused by viruses, bacteria, fungi and protozoan parasites. Moreover important commercial relations exist in marine mollusc culture between different geographical areas. This must be taken into account in explaining the appearance and the spread of some infectious diseases in several countries around the world. The author concentrates on some viral and protozoan diseases of bivalve molluscs reported in the northern hemisphere, in view of their economic impact and their spread related to movement of molluscs through trade.

  17. Microbiological survey for Mycoplasma spp. in a contagious agalactia endemic area.

    PubMed

    De la Fe, C; Assunção, P; Antunes, T; Rosales, R S; Poveda, J B

    2005-09-01

    In this work, we report a microbiological survey for Mycoplasma spp. undertaken between 2001 and 2002 in 28 goat herds in Gran Canaria, Spain, an area where contagious agalactia is endemic. All herds were randomly selected and represented approximately 15.5% of the total goat population of the island. A variable number of milk, articular and auricular swab samples were collected from each flock and cultured in specific mycoplasma culture media. There was a total of 38.5% positive flocks from which 37 mycoplasma isolates were obtained. In contrast with previous data obtained in Spain, our results showed that the large colony variant of M. mycoides subsp. mycoides (Mmm LC) was the most commonly isolated agent associated with contagious agalactia. This species was isolated from 90% of the positive herds and accounted for 54.1% of all isolations. M. agalactiae was isolated from 40% of the positive herds (27% of all isolations) and in six herds M. arginini was isolated (18.7% of all isolations). No M. capricolum or M. putrefaciens strains were isolated. Mycoplasmas were isolated from 21 milk samples, 15 ear canals swabs and one articular sample. The association of several species was reported in several herds. These results are at variance with previous serological studies, which indicated a higher disease prevalence, and suggest that it could be necessary to use detection techniques such PCR to confirm the existence of contagious agalactia in goats.

  18. Applications of network theory to frustrated spin systems and transitions in models of disease spread

    NASA Astrophysics Data System (ADS)

    Stone, Thomas E., Jr.

    This study of network structure and phase transitions focuses on three systems with different dynamical rules: the Ising model with competing ferromagnetic and antiferromagnetic interactions on a 2D triangular lattice, the susceptible-infected-recovered (SIR) epidemic model on an adaptive small-world network, and the SIR model on the Saramaki-Kaski dynamic small-world network. In the Ising model with competing interactions, we employ a novel network construction using the individual spins as nodes and links occurring between two nodes if their spin-spin correlation function exceeds a set threshold. This construction yields the emergence of multiple networks of correlated fluctuations. In the spin-glass-like phase, we find spatially non-contiguous networks of correlated fluctuations, as had been previously predicted by chaotic renormalization-group trajectory arguments, but not confirmed. In the second part of this thesis we turn to a dynamical process, disease spreading, on an adaptive small-world network. The adaptive nature of the contact network means that the social connections can evolve in time, in response to the current states of the individual nodes, creating a feedback mechanism. Unlike previous work, we introduce a method by which this adaptive rewiring is included while maintaining the underlying community structure. This more realistic method can have significant effects on the final size of an outbreak. We also develop a mean-field theory to verify our simulation results in certain limits based on master equation considerations. The third part of this thesis treats a dynamic small-world network, in order to utilize its computational advantages to study the critical phenomena of the disease-free to epidemic phase transition. We solve the dynamical equations for the predicted critical point, and verify this point via finite size scaling arguments. The associated critical exponents are found in a similar manner, which show this model to be in a new

  19. The effects of intranasal oxytocin on contagious yawning.

    PubMed

    Gallup, Andrew C; Church, Allyson M

    2015-10-21

    Contagious yawning is thought to represent a basic form of empathy involved in state matching. Despite recent evidence in support of this connection, the neurochemical basis of contagious yawning remains largely unknown. Here, we investigate whether intranasal oxytocin, a hormone and neuropeptide involved in empathic processing, bonding and social affiliation, influences contagious yawning among human participants in a laboratory setting. Using a double blind procedure, 60 male college students received 30 IU of intranasal oxytocin or placebo and were then recorded during exposure to a contagious yawning video stimulus. Contrary to the empathic modeling hypothesis, oxytocin did not increase contagious yawning but rather appeared to modulate its expression in ways indicative of an enhanced awareness of the social stigma associated with this behavior. In particular, individuals in the oxytocin condition were more likely to conceal their yawns and less likely to display overt cues associated with the behavior. Follow-up research could explore how social context and affiliation with the target stimulus alter this response.

  20. 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.

  1. Live pig markets in eastern Indonesia: Trader characteristics, biosecurity and implications for disease spread.

    PubMed

    Leslie, Edwina E C; Geong, Maria; Abdurrahman, Muktasam; Ward, Michael P; Toribio, Jenny-Ann L M L

    2016-03-01

    Classical swine fever has been negatively impacting pig production in Nusa Tenggara Timur province in eastern Indonesia since its introduction in the 1990s, with live market trade contributing to disease spread. To understand market trader knowledge and practices regarding pig management, biosecurity, pig movements and pig health (specifically CSF), a repeated survey was conducted with pig sellers and pig buyers at 9 market sites across West Timor and the islands of Flores and Sumba. A total of 292 sellers and 281 buyers were interviewed in 2009 during two periods (rounds), a high-demand month (September) and a low-demand month (November). Information was collected via questionnaire. The majority of traders were male (sellers: 89%; buyers: 87%) with the highest level of completed education being primary school (sellers: 48%; buyers: 41%). The primary occupation of most respondents was farming: 90% of sellers and 87% of buyers were smallholder pig farmers and tended to sell their own home-raised pigs at market (52%). Pigs were sold for monetary gain either for primary (52%) or extra income (44%). Markets tended to be selected based on a good reputation (62%), a location close to residence (62%) and having the desired pig type (59%). Pig sales through markets were reported to be highest from August to October with 31% of sellers trading pigs at two or more markets. Prices at market were significantly higher on Sumba compared to West Timor and cross-bred pigs were significantly more expensive than indigenous pigs. Understanding of CSF and biosecurity was limited: 85% of sellers and 83% of buyers had no prior knowledge of CSF. Fifty-four percent of sellers reported no use of any biosecurity practices at market. Most respondents (88%) were able to recognise at least one clinical sign of a sick pig. Informal pig movements were also identified: 18% of pig buyers purchased pigs directly from other farmers. This study has provided baseline information on market trader

  2. Absence of contagious yawning in children with autism spectrum disorder.

    PubMed

    Senju, Atsushi; Maeda, Makiko; Kikuchi, Yukiko; Hasegawa, Toshikazu; Tojo, Yoshikuni; Osanai, Hiroo

    2007-12-22

    This study is the first to report the disturbance of contagious yawning in individuals with autism spectrum disorder (ASD). Twenty-four children with ASD as well as 25 age-matched typically developing (TD) children observed video clips of either yawning or control mouth movements. Yawning video clips elicited more yawns in TD children than in children with ASD, but the frequency of yawns did not differ between groups when they observed control video clips. Moreover, TD children yawned more during or after the yawn video clips than the control video clips, but the type of video clips did not affect the amount of yawning in children with ASD. Current results suggest that contagious yawning is impaired in ASD, which may relate to their impairment in empathy. It supports the claim that contagious yawning is based on the capacity for empathy.

  3. Forecasting the Spread of Mosquito-Borne Disease using Publicly Accessible Data: A Case Study in Chikungunya

    PubMed Central

    Cooper, Kathryn M.; Bastola, Dhundy R.; Gandhi, Robin; Ghersi, Dario; Hinrichs, Steven; Morien, Marsha; Fruhling, Ann

    2016-01-01

    Mosquito-borne diseases account for multiple public health challenges in our modern world. The international health community has seen a number of mosquito-borne diseases come to the forefront in recent years, including West Nile virus, Chikungunya virus, and currently, Zika virus. Predicting the spread of mosquito-borne disease can aid early decision support for when and how to employ public health interventions within a community; however, accurate and fast predictions, months into the future, are difficult to achieve in urgent scenarios, particularly when little information is known about infection rates. New sources of information including social media have been proposed to accelerate the development of predictive models of disease progression. In this research, we adapted a previously described model for the spread of mosquito-borne disease using open intelligence sources. The novel implementation of a mixed-model for mosquito-borne disease was capable of being executed in minimal runtime. The results indicate that this model yields fast and relevant results with acceptable margins of error. PMID:28269838

  4. 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.

  5. Contagious equine metritis in Portugal: A retrospective report of the first outbreak in the country and recent contagious equine metritis test results

    PubMed Central

    Rocha, T.

    2016-01-01

    Contagious equine metritis (CEM), a highly contagious bacterial venereal infection of equids, caused by Taylorella equigenitalis, is of major international concern, causing short-term infertility in mares. Portugal has a long tradition of horse breeding and exportation and until recently was considered CEM-free. However, in 2008, T. equigenitalis was isolated at our laboratory from a recently imported stallion and 2 mares from the same stud. Following this first reported outbreak, the Portuguese Veterinary Authority (DGVA) performed mandatory testing on all remaining equines at the stud (n=30), resulting in a further 4 positive animals. All positive animals were treated and subsequently tested negative for T. equigenitalis. Since this outbreak, over 2000 genital swabs from Portuguese horses have been tested at our laboratory, with no further positive animals identified. The available data suggests that this CEM outbreak was an isolated event and we have no further evidence of CEM cases in Portugal, however, an extended and wider epidemiological study would be needed to better evaluate the incidence of the disease in Portuguese horses. PMID:28116252

  6. Contagious ecthyma in mountain goat of coastal British Columbia.

    PubMed

    Hebert, D M; Samuel, W M; Smith, G W

    1977-04-01

    Contagious ecthyma has been reported previously from mountain goat (Oreamnos americanus) in one restricted area of eastern British Columbia. A second focus of infection is reported for mountain goat from western British Columbia. Diagnosis was based on appearance of lesions at necropsy, histopathology and demonstration of poxvirus with the electron microscope. The epizootiology of this infection in mountain goat is discussed briefly.

  7. Brief Report: Does Eye Contact Induce Contagious Yawning in Children with Autism Spectrum Disorder?

    ERIC Educational Resources Information Center

    Senju, Atsushi; Kikuchi, Yukiko; Akechi, Hironori; Hasegawa, Toshikazu; Tojo, Yoshikuni; Osanai, Hiroo

    2009-01-01

    Individuals with autism spectrum disorder (ASD) reportedly fail to show contagious yawning, but the mechanism underlying the lack of contagious yawning is still unclear. The current study examined whether instructed fixation on the eyes modulates contagious yawning in ASD. Thirty-one children with ASD, as well as 31 age-matched typically…

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

    PubMed

    Ramey, Andrew M; Reeves, Andrew B; Ogawa, Haruko; Ip, Hon S; Imai, Kunitoshi; Bui, Vuong Nghia; Yamaguchi, Emi; Silko, Nikita Y; Afonso, Claudio L

    2013-12-01

    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.

  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. Contagious caprine pleuropneumonia outbreak in captive wild ungulates at Al Wabra Wildlife Preservation, State of Qatar.

    PubMed

    Arif, Abdi; Schulz, Julia; Thiaucourt, François; Taha, Abid; Hammer, Sven

    2007-03-01

    Contagious caprine pleuropneumonia (CCPP) caused by Mycoplasma capricolum subsp. capripneumoniae is a highly contagious and serious respiratory disease of domestic goats, characterized by coughing, severe respiratory distress, and high mortality rates. The lesions at necropsy are mainly a fibrinous pleuropneumonia with increased straw-colored pleural fluid. An outbreak of CCPP in wild goat (Capra aegagrus), Nubian ibex (Capra ibex nubiana), Laristan mouflon (Ovis orientalis laristanica), and gerenuk (Litocranius walleri) occurred at Al Wabra Wildlife Preservation in the State of Qatar. The disease was suspected because of the clinical symptoms and the necropsy findings and was confirmed by the isolation and identification of the causative organism. This new finding indicates that CCPP should be considered a potential threat to wildlife and the conservation of endangered ruminant species, especially in the Middle East, where it is enzootic because of its presence in chronic carriers. Susceptible imported animals should be quarantined and vaccinated. The preferred samples for diagnosis are the pleural fluid, which contains high numbers of Mycoplasma, and sections of hepatized lung, preferably at the interface of normal and diseased tissues. Samples must be shipped to diagnostic laboratories rapidly, and appropriate cool conditions must be maintained during shipping.

  11. Disease spread models to estimate highly uncertain emerging diseases losses for animal agriculture insurance policies: an application to the U.S. farm-raised catfish industry.

    PubMed

    Zagmutt, Francisco J; Sempier, Stephen H; Hanson, Terril R

    2013-10-01

    Emerging diseases (ED) can have devastating effects on agriculture. Consequently, agricultural insurance for ED can develop if basic insurability criteria are met, including the capability to estimate the severity of ED outbreaks with associated uncertainty. The U.S. farm-raised channel catfish (Ictalurus punctatus) industry was used to evaluate the feasibility of using a disease spread simulation modeling framework to estimate the potential losses from new ED for agricultural insurance purposes. Two stochastic models were used to simulate the spread of ED between and within channel catfish ponds in Mississippi (MS) under high, medium, and low disease impact scenarios. The mean (95% prediction interval (PI)) proportion of ponds infected within disease-impacted farms was 7.6% (3.8%, 22.8%), 24.5% (3.8%, 72.0%), and 45.6% (4.0%, 92.3%), and the mean (95% PI) proportion of fish mortalities in ponds affected by the disease was 9.8% (1.4%, 26.7%), 49.2% (4.7%, 60.7%), and 88.3% (85.9%, 90.5%) for the low, medium, and high impact scenarios, respectively. The farm-level mortality losses from an ED were up to 40.3% of the total farm inventory and can be used for insurance premium rate development. Disease spread modeling provides a systematic way to organize the current knowledge on the ED perils and, ultimately, use this information to help develop actuarially sound agricultural insurance policies and premiums. However, the estimates obtained will include a large amount of uncertainty driven by the stochastic nature of disease outbreaks, by the uncertainty in the frequency of future ED occurrences, and by the often sparse data available from past outbreaks.

  12. Serogroup W meningococcal disease: global spread and current affect on the Southern Cone in Latin America.

    PubMed

    Abad, R; López, E L; Debbag, R; Vázquez, J A

    2014-12-01

    Meningococcal serogroup W strains have been emerging throughout the current century with most of the isolates belonging to the sequence type (ST11)/electrophoretic type (ET37) clonal complex (ST11/E37 CC), particularly since the international outbreak following Hajj 2000. That outbreak appears to have triggered off that trend, contributing to the spread of W ST11/ET37 CC strains globally; however, local strains could be also responsible for increases in the percentage and/or incidence rates of this serogroup in some countries. More recently, unexpected increases in the percentage and incidence rate of W has been noticed in different countries located in the South Cone in Latin America, and W ST11/ET37 CC strains now appear as endemic in the region and an extensive immunization programme with tetravalent conjugate vaccine (covering serogroups A, C, Y and W) has been recently implemented in Chile. It is difficult to ascertain whether we are observing the emergence of W ST11 CC strains in different geographical areas or whether the Hajj 2000 strain is still spreading globally. Several aspects of the evolution of that situation are analysed in this paper, reviewing also the implications in immunization programmes. Closely related with the analysis of this potential evolution, it will be very interesting to monitor the evolution of serogroup W in the African meningitis belt after implementation of the extensive immunization programme with serogroup A conjugate vaccine that is currently underway. More data about carriers, transmission, clonal lineages, etc. are needed for taking decisions (target groups, outbreak control, defining the extent, etc.) to adapt the response strategy with potential interventions with broad coverage vaccines against the emergent serogroup W.

  13. 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

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

    PubMed

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

    2014-11-01

    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.

  15. Histopathological study and F1L gene sequence analysis of contagious ecthyma in small ruminants of Shiraz suburb, Iran.

    PubMed

    Davari, S A; Sayyari, M; Mohammadi, A

    2015-06-01

    Contagious ecthyma, also known as Orf, is a common viral skin disease of sheep and goats caused by a Parapoxvirus. This research was conducted with the aims of histopathological study and genetic analysis of Orf virus with PCR technique based on F1L gene in 50 sheep and goats suspicious of contagious ecthyma in affected areas of Shiraz suburb. All 50 contagious ecthyma-like tissue samples were maintained in 10% buffered formalin, embedded in paraffin, sectioned into 5μm slices and dyed with hematoxylin-eosine. The histopathological examination showed 100% positivity. Epidermal hyperplasia with prominent rete ridges, hydropic degeneration of the necrotic keratinocytes, eosinophilic intracytoplasmic inclusion bodies in vacuolated cells and subcorneal pustules were the main hallmarks of this disease. For molecular analysis, after DNA extraction, all samples were amplified by PCR method and the outcome demonstrated positivity in 25 specimens (50%). Of these, 10 definitely positive specimens were analyzed for nucleotide sequencing. Thus, a strain named Orf-059-Shiraz was recorded in the GeneBank and subsequently underwent phylogenetic analysis. The outcome of the molecular study approved half of the positive ecthyma specimens in histopathological method. Furthermore, phylogenetic analysis based on 059 gene showed that this gene is highly conserved. Utilization of histopathology and clinical signs can assist with rapid and low-cost diagnosis of infectious ecthyma whereas PCR is able to dissociate from similar diseases among clinical samples of endemic regions.

  16. Presence of Contagious Yawning in Children with Autism Spectrum Disorder

    PubMed Central

    Kikuchi, Yukiko; Akechi, Hironori; Tojo, Yoshikuni; Osanai, Hiroo; Hasegawa, Toshikazu

    2013-01-01

    Most previous studies suggest diminished susceptibility to contagious yawning in children with autism spectrum disorder (ASD). However, it could be driven by their atypical attention to the face. To test this hypothesis, children with ASD and typically developing (TD) children were shown yawning and control movies. To ensure participants' attention to the face, an eye tracker controlled the onset of the yawning and control stimuli. Results demonstrated that both TD children and children with ASD yawned more frequently when they watched the yawning stimuli than the control stimuli. It is suggested therefore that the absence of contagious yawning in children with ASD, as reported in previous studies, might relate to their weaker tendency to spontaneously attend to others' faces. PMID:23970970

  17. Methodological problems in the study of contagious yawning.

    PubMed

    Campbell, Matthew W; de Waal, Frans B M

    2010-01-01

    The recent interest in contagious yawning has raised several challenges as the varied methods of testing have left some unresolved issues. We do not know how differences in key variables affect the observed rates of yawning, and we highlight these as being in need of direct testing. Different researchers analyze their results differently, and we make some recommendations for more rigorous, thorough and informative analyses. Ultimately, problems arise when authors compare studies that used different methods and different analyses without acknowledging how these differences may have affected the results. In these cases, authors make inappropriate comparisons, which lead to conclusions that add confusion to the literature. Our goal in raising awareness of these issues is to generate new experiments and improve the discussion of existing research. With its link to empathy, a more standardized study of contagious yawning may be a useful tool for a variety of disciplines.

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED PRODUCTS Current Good... diseases. You must recover, process, store, label, package, and distribute HCT/Ps, and screen and test...

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

    PubMed

    Michel, Anita L; Bengis, Roy G

    2012-06-20

    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.

  20. 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

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

    PubMed

    Sellers, R F

    1980-08-01

    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

  2. [The spread of ecology-dependent diseases of the genitourinary system in bioclimatic zones of the Primorskiĭ region].

    PubMed

    Kiku, P F; Gorborukova, T V; Anan'ev, V Iu

    2013-01-01

    The estimation of the prevalence of a class of diseases of the genitourinary system (ICD-10) of the population in the bioclimatic zones of the Primorsky Krai, with taking into account the environmental situation has been performed. The study of the prevalence of diseases of the genitourinary system was carried out with the use of the classical method of data analysis--descriptive statistics. To determine the impact of water quality correlation and regression analysis of the statistical software package SPP has been applied. The study revealed that the diseases of the genitourinary system occupy in the structure of ecology-dependent morbidity in adults--14.9%, in adolescents--13.1% and in children--5.2%, respectively. During the period of 2000-2011 there is noted a trend of the growth of the level of pathology of the genitourinary system. Over the past 5 years, the number of uronefrological patients doubled. Using the a chi-square test for independence, we found that there is a statistically significant correlation (p < or = 0.001) between the level of diseases of the genitourinary system, the bio-climatic zones and zones of ecological situation in all age groups. The use of regression analysis (multiple regression equation) allowed to determine the main parameters of the water module affecting the rate of spread of diseases of the genitourinary system in different bioclimatic zones. The prevalence level of diseases of the genitourinary system in each age group and bioclimatic zone is affected by a certain combination of parameters of the chemical composition of drinking water. The priority of them are by microbial number, Cl-, Fe sum, NO3-, HCO3-, PH, Mg2+, Ca2+. Ranking of the territory in terms of morbidity permitted to determine the problematic situation in the administrative bodies that was taken into account in the development of the program on the prevention of the ecology-dependent diseases of the genitourinary system.

  3. A High Explanatory Power Model of Foot and Mouth Disease Spread in Central California

    DTIC Science & Technology

    2013-03-01

    spongiform encephalopathy and Foot and mouth disease in Great Britain. A dissertation presented in partial fulfillment of the requirements for the degree...Kong, Hong Kong retrieved from www.pnas.org/cgi/doi/10.1073/pnas.0913286107 Stevenson, M. (2003). The Spatio-temporal epidemiology of Bovine

  4. 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.

  5. 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

  6. The network of sheep movements within Great Britain: Network properties and their implications for infectious disease spread.

    PubMed

    Kiss, Istvan Z; Green, Darren M; Kao, Rowland R

    2006-10-22

    During the 2001 foot and mouth disease epidemic in the UK, initial dissemination of the disease to widespread geographical regions was attributed to livestock movement, especially of sheep. In response, recording schemes to provide accurate data describing the movement of large livestock in Great Britain (GB) were introduced. Using these data, we reconstruct directed contact networks within the sheep industry and identify key epidemiological properties of these networks. There is clear seasonality in sheep movements, with a peak of intense activity in August and September and an associated high risk of a large epidemic. The high correlation between the in and out degree of nodes favours disease transmission. However, the contact networks were largely dissasortative: highly connected nodes mostly connect to nodes with few contacts, effectively slowing the spread of disease. This is a result of bipartite-like network properties, with most links occurring between highly active markets and less active farms. When comparing sheep movement networks (SMNs) to randomly generated networks with the same number of nodes and node degrees, despite structural differences (such as disassortativity and higher frequency of even path lengths in the SMNs), the characteristic path lengths within the SMNs are close to values computed from the corresponding random networks, showing that SMNs have 'small-world'-like properties. Using the network properties, we show that targeted biosecurity or surveillance at highly connected nodes would be highly effective in preventing a large and widespread epidemic.

  7. A social contagious model of the obesity epidemic

    NASA Astrophysics Data System (ADS)

    Huang, He; Yan, Zhijun; Chen, Yahong; Liu, Fangyan

    2016-11-01

    Obesity has been recognized as a global epidemic by WHO, followed by many empirical evidences to prove its infectiousness. However, the inter-person spreading dynamics of obesity are seldom studied. A distinguishing feature of the obesity epidemic is that it is driven by a social contagion process which cannot be perfectly described by the infectious disease models. In this paper, we propose a novel belief decision model based on the famous Dempster-Shafer theory of evidence to model obesity epidemic as the competing spread of two obesity-related behaviors: physical inactivity and physical activity. The transition of health states is described by an SIS model. Results reveal the existence of obesity epidemic threshold, above which obesity is quickly eradicated. When increasing the fading level of information spread, enlarging the clustering of initial obese seeds, or introducing small-world characteristics into the network topology, the threshold is easily met. Social discrimination against the obese people plays completely different roles in two cases: on one hand, when obesity cannot be eradicated, social discrimination can reduce the number of obese people; on the other hand, when obesity is eradicable, social discrimination may instead cause it breaking out.

  8. A social contagious model of the obesity epidemic

    PubMed Central

    Huang, He; Yan, Zhijun; Chen, Yahong; Liu, Fangyan

    2016-01-01

    Obesity has been recognized as a global epidemic by WHO, followed by many empirical evidences to prove its infectiousness. However, the inter-person spreading dynamics of obesity are seldom studied. A distinguishing feature of the obesity epidemic is that it is driven by a social contagion process which cannot be perfectly described by the infectious disease models. In this paper, we propose a novel belief decision model based on the famous Dempster-Shafer theory of evidence to model obesity epidemic as the competing spread of two obesity-related behaviors: physical inactivity and physical activity. The transition of health states is described by an SIS model. Results reveal the existence of obesity epidemic threshold, above which obesity is quickly eradicated. When increasing the fading level of information spread, enlarging the clustering of initial obese seeds, or introducing small-world characteristics into the network topology, the threshold is easily met. Social discrimination against the obese people plays completely different roles in two cases: on one hand, when obesity cannot be eradicated, social discrimination can reduce the number of obese people; on the other hand, when obesity is eradicable, social discrimination may instead cause it breaking out. PMID:27892501

  9. Plasma Exosomes Spread and Cluster Around β-Amyloid Plaques in an Animal Model of Alzheimer’s Disease

    PubMed Central

    Zheng, Tingting; Pu, Jiali; Chen, Yanxing; Mao, Yanfang; Guo, Zhangyu; Pan, Hongyu; Zhang, Ling; Zhang, Heng; Sun, Binggui; Zhang, Baorong

    2017-01-01

    Exosomes, a type of extracellular vesicle, have been shown to be involved in many disorders, including Alzheimer’s disease (AD). Exosomes may contribute to the spread of misfolded proteins such as amyloid-β (Aβ) and α-synuclein. However, the specific diffusion process of exosomes and their final destination in brain are still unclear. In the present study, we isolated exosomes from peripheral plasma and injected them into the hippocampus of an AD mouse model, and investigated exosome diffusion. We found that injected exosomes can spread from the dentate gyrus (DG) to other regions of hippocampus and to the cortex. Exosomes targeted microglia preferentially; this phenomenon is stable and is not affected by age. In AD mice, microglia take up lower levels of exosomes. More interestingly, plasma exosomes cluster around the Aβ plaques and are engulfed by activated microglia nearby. Our data indicate that exosomes can diffuse throughout the brain and may play a role in the dynamics of amyloid deposition in AD through microglia. PMID:28203202

  10. Spreading of pathology in neurodegenerative diseases: a focus on human studies

    PubMed Central

    Brettschneider, Johannes; Del Tredici, Kelly; Lee, Virginia M.-Y.; Trojanowski, John Q.

    2015-01-01

    The progression of many neurodegenerative diseases is thought to be driven by the template-directed misfolding, seeded aggregation and cell–cell transmission of characteristic disease-related proteins, leading to the sequential dissemination of pathological protein aggregates. Recent evidence strongly suggests that the anatomical connections made by neurons — in addition to the intrinsic characteristics of neurons, such as morphology and gene expression profile — determine whether they are vulnerable to degeneration in these disorders. Notably, this common pathogenic principle opens up opportunities for pursuing novel targets for therapeutic interventions for these neurodegenerative disorders. We review recent evidence that supports the notion of neuron–neuron protein propagation, with a focus on neuropathological and positron emission tomography imaging studies in humans. PMID:25588378

  11. Spread of Vector-borne Diseases and Neglect of Leishmaniasis, Europe

    PubMed Central

    Campino, Lenea; Cañavate, Carmen; Dedet, Jean-Pierre; Gradoni, Luigi; Soteriadou, Ketty; Mazeris, Apostolos; Ozbel, Yusuf; Boelaert, Marleen

    2008-01-01

    The risk for reintroduction of some exotic vector-borne diseases in Europe has become a hot topic, while the reality of others is neglected at the public health policy level. Leishmaniasis is endemic in all southern countries of Europe, with ≈700 autochthonous human cases reported each year (3,950 if Turkey is included). Asymptomatic cases have been estimated at 30–100/1 symptomatic case, and leishmaniasis has up to 25% seroprevalence in domestic dogs. Even though leishmaniasis is essentially associated with Leishmania infantum and visceral leishmaniasis, new species, such as L. donovani and L. tropica, might colonize European sand fly vectors. Drug-resistant L. infantum strains might be exported outside Europe through dogs. Despite this possibility, no coordinated surveillance of the disease exists at the European level. In this review of leishmaniasis importance in Europe, we would like to bridge the gap between research and surveillance and control. PMID:18598618

  12. Suboptimal Herd Performance Amplifies the Spread of Infectious Disease in the Cattle Industry

    PubMed Central

    Gates, M. Carolyn; Woolhouse, Mark E. J.

    2014-01-01

    Farms that purchase replacement breeding cattle are at increased risk of introducing many economically important diseases. The objectives of this analysis were to determine whether the total number of replacement breeding cattle purchased by individual farms could be reduced by improving herd performance and to quantify the effects of such reductions on the industry-level transmission dynamics of infectious cattle diseases. Detailed information on the performance and contact patterns of British cattle herds was extracted from the national cattle movement database as a case example. Approximately 69% of beef herds and 59% of dairy herds with an average of at least 20 recorded calvings per year purchased at least one replacement breeding animal. Results from zero-inflated negative binomial regression models revealed that herds with high average ages at first calving, prolonged calving intervals, abnormally high or low culling rates, and high calf mortality rates were generally more likely to be open herds and to purchase greater numbers of replacement breeding cattle. If all herds achieved the same level of performance as the top 20% of herds, the total number of replacement beef and dairy cattle purchased could be reduced by an estimated 34% and 51%, respectively. Although these purchases accounted for only 13% of between-herd contacts in the industry trade network, they were found to have a disproportionately strong influence on disease transmission dynamics. These findings suggest that targeting extension services at herds with suboptimal performance may be an effective strategy for controlling endemic cattle diseases while simultaneously improving industry productivity. PMID:24671129

  13. 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.

  14. Outbreaks of infectious intestinal disease associated with person to person spread in hotels and restaurants.

    PubMed

    McDonnell, R J; Wall, P G; Adak, G K; Evans, H S; Cowden, J M; Caul, E O

    1995-09-15

    Twenty-eight outbreaks of infectious intestinal disease, reported as being transmitted mainly by the person to person route, were identified in association with retail catering premises, such as hotels, restaurants, and public houses, in England and Wales between 1992 and 1994. Five thousand and forty-eight people were at risk in these outbreaks and 1234 were affected. Most of the outbreaks (over 90%) occurred in hotels. Small round structured viruses were the most commonly detected pathogens. Diarrhoea and vomiting were common symptoms and most of the outbreaks occurred in the summer months. Control measures to contain infectious individuals and improved hygiene measures are necessary to contain such outbreaks.

  15. 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.

  16. Flying ticks: anciently evolved associations that constitute a risk of infectious disease spread.

    PubMed

    de la Fuente, José; Estrada-Peña, Agustín; Cabezas-Cruz, Alejandro; Brey, Ricardo

    2015-10-15

    Ticks are important vectors of emerging zoonotic diseases affecting human and animal health worldwide. Ticks are often found on wild birds, which have been long recognized as a potential risk factor for dissemination of ticks and tick-borne pathogens (TBP), thus raising societal concerns and prompting research into their biology and ecology. To fully understand the role of birds in disseminating some ticks species and TBP, it is important to consider the evolutionary relationships between birds, ticks and transmitted pathogens. In this paper we reviewed the possible role of birds in the dissemination of TBP as a result of the evolution of host-tick-pathogen associations. Birds are central elements in the ecological networks of ticks, hosts and TBP. The study of host-tick-pathogen associations reveals a prominent role for birds in the dissemination of Borrelia spp. and Anaplasma phagocytophilum, with little contribution to the possible dissemination of other TBP. Birds have played a major role during tick evolution, which explains why they are by far the most important hosts supporting the ecological networks of ticks and several TBP. The immune response of birds to ticks and TBP has been largely overlooked. To implement effective measures for the control of tick-borne diseases, it is necessary to study bird-tick and bird-pathogen molecular interactions including the immune response of birds to tick infestation and pathogen infection.

  17. Perspectives on the role of mobility, behavior, and time scales in the spread of diseases.

    PubMed

    Castillo-Chavez, Carlos; Bichara, Derdei; Morin, Benjamin R

    2016-12-20

    The dynamics, control, and evolution of communicable and vector-borne diseases are intimately connected to the joint dynamics of epidemiological, behavioral, and mobility processes that operate across multiple spatial, temporal, and organizational scales. The identification of a theoretical explanatory framework that accounts for the pattern regularity exhibited by a large number of host-parasite systems, including those sustained by host-vector epidemiological dynamics, is but one of the challenges facing the coevolving fields of computational, evolutionary, and theoretical epidemiology. Host-parasite epidemiological patterns, including epidemic outbreaks and endemic recurrent dynamics, are characteristic to well-identified regions of the world; the result of processes and constraints such as strain competition, host and vector mobility, and population structure operating over multiple scales in response to recurrent disturbances (like El Niño) and climatological and environmental perturbations over thousands of years. It is therefore important to identify and quantify the processes responsible for observed epidemiological macroscopic patterns: the result of individual interactions in changing social and ecological landscapes. In this perspective, we touch on some of the issues calling for the identification of an encompassing theoretical explanatory framework by identifying some of the limitations of existing theory, in the context of particular epidemiological systems. Fostering the reenergizing of research that aims at disentangling the role of epidemiological and socioeconomic forces on disease dynamics, better understood as complex adaptive systems, is a key aim of this perspective.

  18. Perspectives on the role of mobility, behavior, and time scales in the spread of diseases

    PubMed Central

    Castillo-Chavez, Carlos; Bichara, Derdei; Morin, Benjamin R.

    2016-01-01

    The dynamics, control, and evolution of communicable and vector-borne diseases are intimately connected to the joint dynamics of epidemiological, behavioral, and mobility processes that operate across multiple spatial, temporal, and organizational scales. The identification of a theoretical explanatory framework that accounts for the pattern regularity exhibited by a large number of host–parasite systems, including those sustained by host–vector epidemiological dynamics, is but one of the challenges facing the coevolving fields of computational, evolutionary, and theoretical epidemiology. Host–parasite epidemiological patterns, including epidemic outbreaks and endemic recurrent dynamics, are characteristic to well-identified regions of the world; the result of processes and constraints such as strain competition, host and vector mobility, and population structure operating over multiple scales in response to recurrent disturbances (like El Niño) and climatological and environmental perturbations over thousands of years. It is therefore important to identify and quantify the processes responsible for observed epidemiological macroscopic patterns: the result of individual interactions in changing social and ecological landscapes. In this perspective, we touch on some of the issues calling for the identification of an encompassing theoretical explanatory framework by identifying some of the limitations of existing theory, in the context of particular epidemiological systems. Fostering the reenergizing of research that aims at disentangling the role of epidemiological and socioeconomic forces on disease dynamics, better understood as complex adaptive systems, is a key aim of this perspective. PMID:27965394

  19. Regulatable transgenic mouse models of Alzheimer disease: onset, reversibility and spreading of Tau pathology.

    PubMed

    Hochgräfe, Katja; Sydow, Astrid; Mandelkow, Eva-Maria

    2013-09-01

    Accumulation of amyloidogenic proteins such as Tau is a hallmark of neurodegenerative diseases including Alzheimer disease and fronto-temporal dementias. To link Tau pathology to cognitive impairments and defects in synaptic plasticity, we created four inducible Tau transgenic mouse models with expression of pro- and anti-aggregant variants of either full-length human Tau (hTau40/ΔK280 and hTau40/ΔK280/PP) or the truncated Tau repeat domain (Tau(RD)/ΔK280 and Tau(RD)/ΔK280/PP). Here we review the histopathological features caused by pro-aggregant Tau, and correlate them with behavioral deficits and impairments in synaptic transmission. Both pro-aggregant Tau variants cause Alzheimer-like features, including synapse loss, mis-localization of Tau into the somatodendritic compartment, conformational changes and hyperphosphorylation. However, there is a clear difference in the extent of Tau aggregation and neurotoxicity. While pro-aggregant full-length hTau40/ΔK280 leads to a 'pre-tangle' pathology, the repeat domain Tau(RD)/ΔK280 causes massive formation of neurofibrillary tangles and neuronal loss in the hippocampus. However, both Tau variants cause co-aggregation of human and mouse Tau and similar functional impairments. Thus, earlier Tau pathological stages and not necessarily neurofibrillary tangles are critical for the development of cognitive malfunctions. Most importantly, memory and synapses recover after switching off expression of pro-aggregant Tau. The rescue of functional impairments correlates with the rescue of most Tau pathological changes and most strikingly the recovery of synapses. This implies that tauopathies as such are reversible, provided that amyloidogenic Tau is removed. Therefore, our Tau transgenic mice may serve as model systems for in vivo validation of therapeutic strategies and drug candidates with regard to cognition and synaptic function.

  20. 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

  1. Changing social contact patterns under tropical weather conditions relevant for the spread of infectious diseases.

    PubMed

    Chan, T-C; Fu, Y-C; Hwang, J-S

    2015-01-01

    Weather conditions and social contact patterns provide some clues to understanding year-round influenza epidemics in the tropics. Recent studies suggest that contact patterns may direct influenza transmission in the tropics as critically as the aerosol channel in temperate regions. To examine this argument, we analysed a representative nationwide survey dataset of contact diaries with comprehensive weather data in Taiwan. Methods we used included model-free estimated relative changes in reproduction number, R 0; relative changes in the number of contacts; and model-based estimated relative changes in mean contacts using zero-inflated negative binomial regression models. Overall, social contact patterns clearly differ by demographics (such as age groups), personal idiosyncrasies (such as personality and happiness), and social institutions (such as the division of weekdays and weekend days). Further, weather conditions also turn out to be closely linked to contact patterns under various circumstances. Fleeting contacts, for example, tend to diminish when it rains hard on weekdays, while physical contacts also decrease during weekend days with heavy rain. Frequent social contacts on weekdays and under good weather conditions, including high temperature and low absolute humidity, all might facilitate the transmission of infectious diseases in tropical regions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  3. The distribution of parasite strains among hosts affects disease spread in a social insect.

    PubMed

    Ulrich, Yuko; Schmid-Hempel, Paul

    2015-06-01

    Social insects present highly interesting and experimentally amenable systems for the study of disease transmission because they naturally live in dense groups of frequently interacting individuals. Using experimental inoculations of five trypanosomatid strains into groups of its natural host, the bumblebee Bombus terrestris, we investigate the effects of the initial parasite strain distribution across group members on the establishment and transmission success of the different strains to new hosts. For a given number of parasite strains circulating within a host group, transmission to new hosts was increased when the strains were initially inoculated as mixed infections (as opposed to separate single infections), presumably because mixed infections generally favored fast replicating strains. In contrast, separate single infections reduced transmission at least in part through a precedence effect, whereby weak strains appeared to persist by making their host unavailable to superinfection. These results suggest that host groups could benefit from 'compartmentalizing' infections by different parasite strains across different group members, which might be achieved in social insects, for example, by division of labor.

  4. Spreading of infectious diseases considering age contact patterns for Latin America

    NASA Astrophysics Data System (ADS)

    Pastore Y Piontti, Ana; Gomes, Marcelo F. C.; Rossi, Luca; Vespignani, Alessandro

    2013-03-01

    The dynamics of infectious diseases strongly depends on the structure of the social contact patterns among individuals. In order to have an accurate estimate of the impact of epidemic outbreaks and which effective control measures to take, we need an appropriate description of these patterns. A simple way to improve the homogeneous mixing assumption is to introduce age contact patterns. Here we follow the approach of Fumanelli et al (PLoS Computational Biology, 8(9):e1002673, 2012) to estimate the age mixing patterns of virtual populations using highly detailed census data for Argentina, Brazil and Mexico. Considering age contact matrices for these countries we study the epidemiological relevant quantities and their relation with the sociodemographic data. Our results show that even for the same country the impact of epidemics outbreaks could be very different when we consider age contact matrices. This results can be explained as a result of a change in the average age of the population in the different regions of the countries. This study also provides the first estimates of contact matrices for Latin American countries.

  5. Dynamic social networks and the implications for the spread of infectious disease.

    PubMed

    Read, Jonathan M; Eames, Ken T D; Edmunds, W John

    2008-09-06

    Understanding the nature of human contact patterns is crucial for predicting the impact of future pandemics and devising effective control measures. However, few studies provide a quantitative description of the aspects of social interactions that are most relevant to disease transmission. Here, we present the results from a detailed diary-based survey of casual (conversational) and close contact (physical) encounters made by a small peer group of 49 adults who recorded 8,661 encounters with 3,528 different individuals over 14 non-consecutive days. We find that the stability of interactions depends on the intimacy of contact and social context. Casual contact encounters mostly occur in the workplace and are predominantly irregular, while close contact encounters mostly occur at home or in social situations and tend to be more stable. Simulated epidemics of casual contact transmission involve a large number of non-repeated encounters, and the social network is well captured by a random mixing model. However, the stability of the social network should be taken into account for close contact infections. Our findings have implications for the modelling of human epidemics and planning pandemic control policies based on social distancing methods.

  6. Evaluation of the risk of classical swine fever (CSF) spread from backyard pigs to other domestic pigs by using the spatial stochastic disease spread model Be-FAST: the example of Bulgaria.

    PubMed

    Martínez-López, Beatriz; Ivorra, Benjamin; Ramos, Angel Manuel; Fernández-Carrión, Eduardo; Alexandrov, Tsviatko; Sánchez-Vizcaíno, José Manuel

    2013-07-26

    The study presented here is one of the very first aimed at exploring the potential spread of classical swine fever (CSF) from backyard pigs to other domestic pigs. Specifically, we used a spatial stochastic spread model, called Be-FAST, to evaluate the potential spread of CSF virus (CSFV) in Bulgaria, which holds a large number of backyards (96% of the total number of pig farms) and is one of the very few countries for which backyard pigs and farm counts are available. The model revealed that, despite backyard pigs being very likely to become infected, infections from backyard pigs to other domestic pigs were rare. In general, the magnitude and duration of the CSF simulated epidemics were small, with a median [95% PI] number of infected farms per epidemic of 1 [1,4] and a median [95% PI] duration of the epidemic of 44 [17,101] days. CSFV transmission occurs primarily (81.16%) due to indirect contacts (i.e. vehicles, people and local spread) whereas detection of infected premises was mainly (69%) associated with the observation of clinical signs on farm rather than with implementation of tracing or zoning. Methods and results of this study may support the implementation of risk-based strategies more cost-effectively to prevent, control and, ultimately, eradicate CSF from Bulgaria. The model may also be easily adapted to other countries in which the backyard system is predominant. It can also be used to simulate other similar diseases such as African swine fever.

  7. A severe case of contagious ecthyma in Tswana goats.

    PubMed

    Baipoledi, E K; Nyange, J F C; Hyera, J M K

    2002-06-01

    The first severe case of caprine contagious ecthyma (parapox) in Tswana goats is described from Botswana. Affected animals were indigenous adult Tswana goats. The case involved a flock of 12 goats of which 4 (33.3%) were very severely affected but none died. The lesions were confined to the head and included swollen lips, swollen submandibular lymph nodes, gingivitis, glossitis, ulceration on lip and gum mucosae and scab formation on ulcerated areas. No lesions were found on other parts of the body. This case was clinically indistinguishable from bluetongue.

  8. Modeling Mosquito-Borne Disease Spread in U.S. Urbanized Areas: The Case of Dengue in Miami

    PubMed Central

    Robert, Michael A.; Christofferson, Rebecca C.; Silva, Noah J. B.; Vasquez, Chalmers; Mores, Christopher N.; Wearing, Helen J.

    2016-01-01

    Expansion of mosquito-borne pathogens into more temperate regions of the world necessitates tools such as mathematical models for understanding the factors that contribute to the introduction and emergence of a disease in populations naïve to the disease. Often, these models are not developed and analyzed until after a pathogen is detected in a population. In this study, we develop a spatially explicit stochastic model parameterized with publicly available U.S. Census data for studying the potential for disease spread in Urbanized Areas of the United States. To illustrate the utility of the model, we specifically study the potential for introductions of dengue to lead to autochthonous transmission and outbreaks in a population representative of the Miami Urbanized Area, where introductions of dengue have occurred frequently in recent years. We describe seasonal fluctuations in mosquito populations by fitting a population model to trap data provided by the Miami-Dade Mosquito Control Division. We show that the timing and location of introduced cases could play an important role in determining both the probability that local transmission occurs as well as the total number of cases throughout the entire region following introduction. We show that at low rates of clinical presentation, small outbreaks of dengue could go completely undetected during a season, which may confound mitigation efforts that rely upon detection. We discuss the sensitivity of the model to several critical parameter values that are currently poorly characterized and motivate the collection of additional data to strengthen the predictive power of this and similar models. Finally, we emphasize the utility of the general structure of this model in studying mosquito-borne diseases such as chikungunya and Zika virus in other regions. PMID:27532496

  9. Estimating contact patterns relevant to the spread of infectious diseases in Russia.

    PubMed

    Ajelli, Marco; Litvinova, Maria

    2017-02-01

    Understanding human mixing patterns is the key to provide public health decision makers with model-based evaluation of strategies for the control of infectious diseases. Here we conducted a population-based survey in Tomsk, Russia, asking participants to record all their contacts in physical person during the day. We estimated 9.8 contacts per person per day on average, 15.2 when including additional estimated professional contacts. We found that contacts were highly assortative by age, especially for school-age individuals, and the number of contacts negatively correlated with the age of the participant. The network of contacts was quite clustered, with the majority of contacts (about 72%) occurring between family members, students of the same school/university, and work colleagues. School represents the location where the largest number of contacts was recorded - students contacted about 7 individuals per day at school. Our modeling analysis based on the recorded contact patterns supports the importance of modeling age-mixing patterns - we show that, in the case of an epidemic caused by a novel influenza virus, school-age individuals would be the most affected age group, followed by adults aged 35-44 years. In conclusion, this study reveals an age-mixing pattern in general agreement with that estimated for European countries, although with several quantitative differences. The observed differences can be attributable to sociodemographic and cultural differences between countries. The age- and setting-specific contact matrices provided in this study could be instrumental for the design of control measures for airborne infections, specifically targeted on the characteristics of the Russian population.

  10. Yawn, yawn, yawn, yawn; yawn, yawn, yawn! The social, evolutionary and neuroscientific facets of contagious yawning.

    PubMed

    Platek, Steven M

    2010-01-01

    Contagious yawning is a common phenomenon affecting upwards of 60% of healthy humans. It has also been observed, at a lesser rate, in great apes and other primates. Here I summarize the suggestion that contagious yawning is a primitive expression of social cognition, namely empathy. Susceptibility to contagious yawning is correlated with the speed in recognizing one's own face, theory of mind processing, and is also associated with activation in regions of the brain that have been associated with social cognitive processes. This suggests that contagious yawning may be an evolutionarily old process that begot a higher level of social cognition in certain species.

  11. Demodex gatoi -associated contagious pruritic dermatosis in cats - a report from six households in Finland

    PubMed Central

    Saari, Seppo AM; Juuti, Kirsi H; Palojärvi, Joanna H; Väisänen, Kirsi M; Rajaniemi, Riitta-Liisa; Saijonmaa-Koulumies, Leena E

    2009-01-01

    Background Demodex gatoi is unique among demodectic mites. It possesses a distinct stubby appearance, and, instead of residing in the hair follicles, it dwells in the keratin layer of the epidermis, causing a pruritic and contagious skin disease in cats. Little is known of the occurrence of D. gatoi in Europe or control of D. gatoi infestation. Case presentation We describe D. gatoi in 10 cats, including five Cornish Rex, two Burmese, one Exotic, one Persian and one Siamese, living in six multi-cat households in different locations in Finland containing 21 cats in total. Intense pruritus was the main clinical sign. Scaling, broken hairs, alopecia and self-inflicted excoriations were also observed. Diagnosis was based on finding typical short-bodied demodectic mites in skin scrapings, skin biopsies or on tape strips. Other pruritic skin diseases, such as allergies and dermatophytoses, were ruled out. In one household, despite finding several mites on one cat, all six cats of the household remained symptomless. Amitraz used weekly at a concentration of 125-250 ppm for 2-3 months, proved successful in three households, 2% lime sulphur weekly dips applied for six weeks in one household and peroral ivermectin (1 mg every other day for 10 weeks) in one household. Previous trials in four households with imidacloprid-moxidectin, selamectin or injected ivermectin given once or twice a month appeared ineffective. Conclusion D. gatoi-associated dermatitis is an emerging contagious skin disease in cats in Finland. Although pruritus is common, some cats may harbour the mites without clinical signs. In addition, due to translucency of the mites and fastidious feline grooming habits, the diagnosis may be challenging. An effective and convenient way to treat D. gatoi infestations has yet to emerge. PMID:19843334

  12. [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.

  13. How social structures, space, and behaviors shape the spread of infectious diseases using chikungunya as a case study

    PubMed Central

    Salje, Henrik; Lessler, Justin; Azman, Andrew S.; Rahman, M. Waliur; Rahman, Mahmudur; Cummings, Derek; Gurley, Emily S.; Cauchemez, Simon

    2016-01-01

    Whether an individual becomes infected in an infectious disease outbreak depends on many interconnected risk factors, which may relate to characteristics of the individual (e.g., age, sex), his or her close relatives (e.g., household members), or the wider community. Studies monitoring individuals in households or schools have helped elucidate the determinants of transmission in small social structures due to advances in statistical modeling; but such an approach has so far largely failed to consider individuals in the wider context they live in. Here, we used an outbreak of chikungunya in a rural community in Bangladesh as a case study to obtain a more comprehensive characterization of risk factors in disease spread. We developed Bayesian data augmentation approaches to account for uncertainty in the source of infection, recall uncertainty, and unobserved infection dates. We found that the probability of chikungunya transmission was 12% [95% credible interval (CI): 8–17%] between household members but dropped to 0.3% for those living 50 m away (95% CI: 0.2–0.5%). Overall, the mean transmission distance was 95 m (95% CI: 77–113 m). Females were 1.5 times more likely to become infected than males (95% CI: 1.2–1.8), which was virtually identical to the relative risk of being at home estimated from an independent human movement study in the country. Reported daily use of antimosquito coils had no detectable impact on transmission. This study shows how the complex interplay between the characteristics of an individual and his or her close and wider environment contributes to the shaping of infectious disease epidemics. PMID:27821727

  14. A case of contagious toxicity? Isoprostanes as potential emerging contaminants of concern.

    PubMed

    Gaw, Sally; Glover, Chris N

    2016-08-01

    Isoprostanes are useful biomarkers of human and animal health, being representative of oxidative stress processes, and having biological impacts associated with toxicity and disease. Isoprostanes are also chemically stable, a property facilitating population-level health assessments through wastewater sampling. However, as biologically-active entities, the presence of isoprostanes in domestic effluents could have toxic impacts on biota in receiving environments. As such it is proposed that isoprostanes are emerging organic contaminants of particular concern. Fish and aquatic invertebrates may be affected by the presence of isoprostanes in wastewaters through mechanisms such as reproductive impairment, cardiovascular disturbance and/or oxidative stress. This would represent a unique scenario of "contagious" toxicity, whereby human health has a direct toxicological consequence on aquatic animal health.

  15. 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.

  16. Contagious ecthyma in bighorn sheep and mountain goat in western Canada.

    PubMed

    Samuel, W M; Chalmers, G A; Stelfox, J G; Loewen, A; Thomsen, J J

    1975-01-01

    Contagious ecthyma (CE) is reported in bighorn sheep (Ovis c. canadensis) from several national parks in western Canada and in moutain goat (Oreamnos americanus) from Kootenay National Park, British Columbia. (This is the first report of CE in mountain goat.) Diagnosis was based on clinical signs, histopathology, transmission experiments and the demonstration of a proxvirus with the electron microscope. The infection was transmitted from wild to domestic goat, but not to domestic sheep. Most infections, some of them severe, were found in lambs and kids. Clinical signs of disease were similar to those seen in domestic sheep and goats. General body condition was poor and animals had difficulty feeding normally. All infected herds had prolonged contact with areas where salt was provided artificially (i.e., salt blocks, highways and campgrounds). Fewer infected sheep were observed annually when salt blocks were removed from Jasper National Park.

  17. Effects of human dynamics on epidemic spreading in Côte d'Ivoire

    NASA Astrophysics Data System (ADS)

    Li, Ruiqi; Wang, Wenxu; Di, Zengru

    2017-02-01

    Understanding and predicting outbreaks of contagious diseases are crucial to the development of society and public health, especially for underdeveloped countries. However, challenging problems are encountered because of complex epidemic spreading dynamics influenced by spatial structure and human dynamics (including both human mobility and human interaction intensity). We propose a systematical model to depict nationwide epidemic spreading in Côte d'Ivoire, which integrates multiple factors, such as human mobility, human interaction intensity, and demographic features. We provide insights to aid in modeling and predicting the epidemic spreading process by data-driven simulation and theoretical analysis, which is otherwise beyond the scope of local evaluation and geometrical views. We show that the requirement that the average local basic reproductive number to be greater than unity is not necessary for outbreaks of epidemics. The observed spreading phenomenon can be roughly explained as a heterogeneous diffusion-reaction process by redefining mobility distance according to the human mobility volume between nodes, which is beyond the geometrical viewpoint. However, the heterogeneity of human dynamics still poses challenges to precise prediction.

  18. 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.

  19. Characterizing super-spreading in microblog: An epidemic-based information propagation model

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Wang, Bai; Wu, Bin; Shang, Suiming; Zhang, Yunlei; Shi, Chuan

    2016-12-01

    As the microblogging services are becoming more prosperous in everyday life for users on Online Social Networks (OSNs), it is more favorable for hot topics and breaking news to gain more attraction very soon than ever before, which are so-called "super-spreading events". In the information diffusion process of these super-spreading events, messages are passed on from one user to another and numerous individuals are influenced by a relatively small portion of users, a.k.a. super-spreaders. Acquiring an awareness of super-spreading phenomena and an understanding of patterns of wide-ranged information propagations benefits several social media data mining tasks, such as hot topic detection, predictions of information propagation, harmful information monitoring and intervention. Taking into account that super-spreading in both information diffusion and spread of a contagious disease are analogous, in this study, we build a parameterized model, the SAIR model, based on well-known epidemic models to characterize super-spreading phenomenon in tweet information propagation accompanied with super-spreaders. For the purpose of modeling information diffusion, empirical observations on a real-world Weibo dataset are statistically carried out. Both the steady-state analysis on the equilibrium and the validation on real-world Weibo dataset of the proposed model are conducted. The case study that validates the proposed model shows that the SAIR model is much more promising than the conventional SIR model in characterizing a super-spreading event of information propagation. In addition, numerical simulations are carried out and discussed to discover how sensitively the parameters affect the information propagation process.

  20. A Comparative Assessment of the Risks of Introduction and Spread of Foot-and-Mouth Disease among Different Pig Sectors in Australia

    PubMed Central

    Hernández-Jover, Marta; Schembri, Nicole; Holyoake, Patricia K.; Toribio, Jenny-Ann L. M. L.; Martin, Peter Anthony Julian

    2016-01-01

    Small-scale pig producers are believed to pose higher biosecurity risks for the introduction and spread of exotic diseases than commercial pig producers. However, the magnitude of these risks is poorly understood. This study is a comparative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) through different sectors of the pig industry: (1) large-scale pig producers; (2) small-scale producers (<100 sows) selling at saleyards and abattoirs; and (3) small-scale producers selling through informal means. An exposure and consequence assessments were conducted using the World Organization for Animal Health methodology for risk analysis, assuming FMD virus was introduced into Australia through illegal importation of infected meat. A quantitative assessment, using scenario trees and Monte Carlo stochastic simulation, was used to calculate the probabilities of exposure and spread. Input data for these assessments were obtained from a series of data gathering exercises among pig producers, industry statistics, and literature. Findings of this study suggest there is an Extremely low probability of exposure (8.69 × 10−6 to 3.81 × 10−5) for the three sectors of the pig industry, with exposure through direct swill feeding being 10–100 times more likely to occur than through contact with infected feral pigs. Spread of FMD from the index farm is most likely to occur through movement of contaminated fomites, pigs, and ruminants. The virus is more likely to spread from small-scale piggeries selling at saleyards and abattoirs than from other piggeries. The most influential factors on the spread of FMD from the index farm is the ability of the farmer to detect FMD, the probability of FMD spread through contaminated fomites and the presence of ruminants on the farm. Although small-scale producers selling informally move animals less frequently and do not use external staff, movement of pigs to non-commercial pathways could jeopardize

  1. 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.

  2. Experimental contagious ecthyma in mule deer, white-tailed deer, pronghorn and wapiti.

    PubMed

    Lance, W R; Hibler, C P; DeMartini, J

    1983-07-01

    Hand-reared mule deer fawns (Odocoileus hemionus), white-tailed deer fawns (Odocoileus virginianus), pronghorn fawns (Antilocapra americana) and wapiti calves (Cervus elaphus nelsoni) were exposed to contagious ecthyma lesion material obtained from Rocky Mountain bighorn sheep (Ovis canadensis canadensis) to determine the susceptibility and pathogenesis in these species. All four species developed mucocutaneous proliferative lesions of the oral cavity, grossly and histologically compatible with contagious ecthyma. The limited clinical responses to the virus indicated that contagious ecthyma would not seriously impact free-ranging individuals.

  3. Is obesity contagious by way of body image? A study on Japanese female students in the United States.

    PubMed

    Bagrowicz, Rinako; Watanabe, Chiho; Umezaki, Masahiro

    2013-10-01

    Although it has been suggested that obesity is 'contagious' within the social network, direct cause of this spread of obesity remains unclear. This study hypothesized that Body Image (BI), the perception of one's own body size, may play a role in this obesity spread, since a high prevalence of obesity could shift people's perception of 'what is normal'. Young Japanese females (n = 53) were interviewed within 1 month after moving to New York City, where the prevalence of obesity is substantially higher than that of their home country, Japan. Each participant was examined for her BI in terms of current body size (CBS) and ideal body size (IBS). They were interviewed again 2 months after the first examination. Between the two interviews, the participants' CBS was decreased (having thinner self-image), while the IBS increased (having fatter ideal-image), leading to less dissatisfaction (smaller CBS-IBS) with their body size. These results suggest that one's BI could change in a period as short as 2 months, possibly because of being surrounded by more obese people. The IBS change was positively associated with BMI change (increased by 0.4 ± 0.6 kg/m²), warranting further study on the role of BI in the spread of obesity.

  4. Genetic Control of Contagious Asexuality in the Pea Aphid

    PubMed Central

    Jaquiéry, Julie; Stoeckel, Solenn; Larose, Chloé; Nouhaud, Pierre; Rispe, Claude; Mieuzet, Lucie; Bonhomme, Joël; Mahéo, Frédérique; Legeai, Fabrice; Gauthier, Jean-Pierre; Prunier-Leterme, Nathalie; Tagu, Denis; Simon, Jean-Christophe

    2014-01-01

    Although evolutionary transitions from sexual to asexual reproduction are frequent in eukaryotes, the genetic bases of such shifts toward asexuality remain largely unknown. We addressed this issue in an aphid species where both sexual and obligate asexual lineages coexist in natural populations. These sexual and asexual lineages may occasionally interbreed because some asexual lineages maintain a residual production of males potentially able to mate with the females produced by sexual lineages. Hence, this species is an ideal model to study the genetic basis of the loss of sexual reproduction with quantitative genetic and population genomic approaches. Our analysis of the co-segregation of ∼300 molecular markers and reproductive phenotype in experimental crosses pinpointed an X-linked region controlling obligate asexuality, this state of character being recessive. A population genetic analysis (>400-marker genome scan) on wild sexual and asexual genotypes from geographically distant populations under divergent selection for reproductive strategies detected a strong signature of divergent selection in the genomic region identified by the experimental crosses. These population genetic data confirm the implication of the candidate region in the control of reproductive mode in wild populations originating from 700 km apart. Patterns of genetic differentiation along chromosomes suggest bidirectional gene flow between populations with distinct reproductive modes, supporting contagious asexuality as a prevailing route to permanent parthenogenesis in pea aphids. This genetic system provides new insights into the mechanisms of coexistence of sexual and asexual aphid lineages. PMID:25473828

  5. 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

  6. Ingroup-outgroup bias in contagious yawning by chimpanzees supports link to empathy.

    PubMed

    Campbell, Matthew W; de Waal, Frans B M

    2011-04-06

    Humans favor others seen as similar to themselves (ingroup) over people seen as different (outgroup), even without explicitly stated bias. Ingroup-outgroup bias extends to involuntary responses, such as empathy for pain. However, empathy biases have not been tested in our close primate relatives. Contagious yawning has been theoretically and empirically linked to empathy. If empathy underlies contagious yawning, we predict that subjects should show an ingroup-outgroup bias by yawning more in response to watching ingroup members yawn than outgroup. Twenty-three chimpanzees (Pan troglodytes) from two separate groups watched videos of familiar and unfamiliar individuals yawning or at rest (control). The chimpanzees yawned more when watching the familiar yawns than the familiar control or the unfamiliar yawns, demonstrating an ingroup-outgroup bias in contagious yawning. These results provide further empirical support that contagious yawning is a measure of empathy, which may be useful for evolutionary biology and mental health.

  7. Brief report: does eye contact induce contagious yawning in children with autism spectrum disorder?

    PubMed

    Senju, Atsushi; Kikuchi, Yukiko; Akechi, Hironori; Hasegawa, Toshikazu; Tojo, Yoshikuni; Osanai, Hiroo

    2009-11-01

    Individuals with autism spectrum disorder (ASD) reportedly fail to show contagious yawning, but the mechanism underlying the lack of contagious yawning is still unclear. The current study examined whether instructed fixation on the eyes modulates contagious yawning in ASD. Thirty-one children with ASD, as well as 31 age-matched typically developing (TD) children, observed video clips of either yawning or control mouth movements. Participants were instructed to fixate to the eyes of the face stimuli. Following instructed fixation on the eyes, both TD children and children with ASD yawned equally frequently in response to yawning stimuli. Current results suggest that contagious yawning could occur in ASD under an experimental condition in which they are instructed to fixate on the yawning eyes.

  8. 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

  9. On the spread of the novel influenza A (H1N1) virus in Mexico.

    PubMed

    López-Cervantes, Malaquías; Venado, Aida; Moreno, Andrés; Pacheco-Domínguez, Reyna L; Ortega-Pierres, Guadalupe

    2009-06-01

    A novel influenza A H1N1 virus of swine origin is responsible for the influenza epidemic affecting Mexico, the United States of America (USA), and 39 other countries. While the origin of this emerging pathogen remains uncertain, an increase in the reported incidence of respiratory diseases was noted during March 2009 at the town of La Gloria, in the southeastern state of Veracruz, Mexico. So far, this is the first community in which a case of novel influenza A H1N1 virus has been identified. Further cases were rapidly detected in other areas of Mexico and elsewhere. Initially, the atypical respiratory disease outbreak caused great uncertainty posing a challenge to the Mexican health system. Control measures such as social distancing, timely medical care, and personal hygiene have so far proven effective in containing the outbreak, resulting in a decline of the number of new cases. To the best of our knowledge, it appears that the virus might not be as virulent or contagious as previously thought. Here we provide a description of the influenza epidemic spread in Mexico. As the virus disseminates worldwide, there is concern about the possibility of a new reassortment resulting in a more pathogenic strain that will pose a threat for every country. The influenza epidemic provided lessons that underscore the importance of epidemiologic surveillance and preparedness. Further investigation to address questions about this new virus and conditions for its spread is warranted.

  10. 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

  11. 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.

  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.

  13. A contagious bovine pleuropneumonia outbreak on a research farm in Ethiopia, and its dynamics over an eight-month period.

    PubMed

    Almaw, G; Duguma, M; Wubetie, A; Tuli, G; Koran, T

    2016-12-01

    Contagious bovine pleuropneumonia (CBPP) was recognised on Bako Agricultural Research Farm, in the Oromia Region of Ethiopia, for the first time on 5 May 2011. The outbreak was investigated by combining recognition of clinical signs, post-mortem examination, mycoplasma isolation and serological testing using competitive enzymelinked immunosorbent assay (c-ELISA). The clinical cases were monitored for eight months; sick animals were treated with a range of antibiotics and isolated if necessary. The outbreak of CBPP was confirmed both bacteriologically and serologically and had spread to almost the entire herd (96.7%) within the eight-month observation period. Of the animals that recovered after antibiotic treatment, 12.3% fell sick again, showed typical signs of CBPP and were considered to be carriers. The role of treatment in the prevention of the spread of CBPP was minimal. Newly purchased animals that were not tested and quarantined before being introduced onto the farm were suspected to have been the most probable source of infection.

  14. 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...

  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. Familiarity bias and physiological responses in contagious yawning by dogs support link to empathy.

    PubMed

    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.

  17. 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.

  18. Assessing the potential spread and maintenance of foot-and-mouth disease virus infection in wild ungulates: general principles and application to a specific scenario in Thrace.

    PubMed

    Dhollander, S; Belsham, G J; Lange, M; Willgert, K; Alexandrov, T; Chondrokouki, E; Depner, K; Khomenko, S; Özyörük, F; Salman, M; Thulke, H H; Bøtner, A

    2016-04-01

    Foot-and-mouth disease (FMD), due to infection with serotype O virus, occurred in wild boar and within eleven outbreaks in domestic livestock in the south-east of Bulgaria, Thrace region, in 2011. Hence, the issue of the potential for the spread and maintenance of FMD virus (FMDV) infection in a population of wild ungulates became important. This assessment focused on the spread and maintenance of FMDV infection within a hypothetical wild boar and deer population in an environment, which is characterized by a climate transitional between Mediterranean and continental and variable wildlife population densities. The assessment was based on three aspects: (i) a systematic review of the literature focusing on experimental infection studies to identify the parameters describing the duration of FMDV infection in deer and wild boar, as well as observational studies assessing the occurrence of FMDV infection in wild deer and wild boar populations, (ii) prevalence survey data of wild boar and deer in Bulgaria and Turkey and (iii) an epidemiological model, simulating the host-to-host spread of FMDV infections. It is concluded, based on all three aspects, that the wildlife population in Thrace, and so wildlife populations in similar ecological settings, are probably not able to maintain FMD in the long term in the absence of FMDV infection in the domestic host population. However, limited spread of FMDV infection in time and space in the wildlife populations can occur. If there is a continued cross-over of FMDV between domestic and wildlife populations or a higher population density, virus circulation may be prolonged.

  19. Paraneoplastic pemphigus associated with Castleman disease: Progression from mucous to mucocutaneous lesions with epitope-spreading phenomena.

    PubMed

    Okahashi, K; Oiso, N; Ishii, N; Miyake, M; Uchida, S; Matsuda, H; Kitano, M; Hida, J; Kawai, S; Sano, A; Hashimoto, T; Kawada, A

    2017-02-18

    Paraneoplastic pemphigus (PNP) is a frequently fatal autoimmune blistering disease of the skin and mucous membranes.(1) PNP is commonly associated with malignant neoplasms or haematological disorders like Castleman disease (CD). The eruptions may resemble those seen in various other conditions such as lichen planus (LP), graft-versus-host disease, erythema multiforme (EM), bullous pemphigoid and pemphigus vulgaris (PV).(2) This article is protected by copyright. All rights reserved.

  20. Infection-induced behavioural changes reduce connectivity and the potential for disease spread in wild mice contact networks

    PubMed Central

    Lopes, Patricia C.; Block, Per; König, Barbara

    2016-01-01

    Infection may modify the behaviour of the host and of its conspecifics in a group, potentially altering social connectivity. Because many infectious diseases are transmitted through social contact, social connectivity changes can impact transmission dynamics. Previous approaches to understanding disease transmission dynamics in wild populations were limited in their ability to disentangle different factors that determine the outcome of disease outbreaks. Here we ask how social connectivity is affected by infection and how this relationship impacts disease transmission dynamics. We experimentally manipulated disease status of wild house mice using an immune challenge and monitored social interactions within this free-living population before and after manipulation using automated tracking. The immune-challenged animals showed reduced connectivity to their social groups, which happened as a function of their own behaviour, rather than through conspecific avoidance. We incorporated these disease-induced changes of social connectivity among individuals into models of disease outbreaks over the empirically-derived networks. The models revealed that changes in host behaviour frequently resulted in the disease being contained to very few animals, as opposed to becoming widespread. Our results highlight the importance of considering the role that behavioural alterations during infection can have on social dynamics when evaluating the potential for disease outbreaks. PMID:27548906

  1. Analysis of the Spatial Organization of Pastures as a Contact Network, Implications for Potential Disease Spread and Biosecurity in Livestock, France, 2010

    PubMed Central

    Palisson, Aurore; Courcoul, Aurélie; Durand, Benoit

    2017-01-01

    The use of pastures is part of common herd management practices for livestock animals, but contagion between animals located on neighbouring pastures is one of the major modes of infectious disease transmission between herds. At the population level, this transmission is strongly constrained by the spatial organization of pastures. The aim of this study was to answer two questions: (i) is the spatial configuration of pastures favourable to the spread of infectious diseases in France? (ii) would biosecurity measures allow decreasing this vulnerability? Based on GIS data, the spatial organization of pastures was represented using networks. Nodes were the 3,159,787 pastures reported in 2010 by the French breeders to claim the Common Agricultural Policy subsidies. Links connected pastures when the distance between them was below a predefined threshold. Premises networks were obtained by aggregating into a single node all the pastures under the same ownership. Although the pastures network was very fragmented when the distance threshold was short (1.5 meters, relevant for a directly-transmitted disease), it was not the case when the distance threshold was larger (500 m, relevant for a vector-borne disease: 97% of the nodes in the largest connected component). The premises network was highly connected as the largest connected component always included more than 83% of the nodes, whatever the distance threshold. Percolation analyses were performed to model the population-level efficacy of biosecurity measures. Percolation thresholds varied according to the modelled biosecurity measures and to the distance threshold. They were globally high (e.g. >17% of nodes had to be removed, mimicking the confinement of animals inside farm buildings, to obtain the disappearance of the large connected component). The network of pastures thus appeared vulnerable to the spread of diseases in France. Only a large acceptance of biosecurity measures by breeders would allow reducing this

  2. Social network analysis of Equidae movements and its application to risk-based surveillance and to control of spread of potential Equidae diseases.

    PubMed

    Sánchez-Matamoros, A; Martínez-López, B; Sánchez-Vizcaíno, F; Sánchez-Vizcaíno, J M

    2013-10-01

    Movements of animals and animal products are one of the most important ways of disease introduction and spread between regions and countries. Maybe one of the most complex animal species in terms of diversity of uses, nature and extent of movements are equidae, for which animal movement records are usually not available. The study presented here is the first characterization of a complete and reliable network of equidae movements in Castile and Leon, which is one of the most important equidae production regions of Spain. Social network analysis and space-time cluster analysis were used to describe the contact patterns of the equidae network and to identify the most important premises, areas and time periods for potential disease introduction or spread into the region. The studied network was complex, with very heterogeneous types of premises and diverse nature and extent of the movements compared with other livestock species, which have important implications for prevention and control of equidae diseases. Centrality measures revealed that production and reproduction farms and centres of livestock competition were the most important type of premises in the studied network. Cluster analyses allowed to identify seventeen significant spatio-temporal clusters of premises at high risk of dispatching or receiving equidae, which formed four interconnected compartments. These clusters were mainly located in the north-west region and in the second part of the year. The results of this study may be useful to design risk-based surveillance and control programmes of equidae diseases and increase the speed of detection and control of potential secondary outbreaks in future epidemics. Consequently, these results will help to minimize the great economic and sanitary impact of equidae diseases. The analytical approach used here may be easily extended to characterize the equidae movement patterns in other countries and regions of the world.

  3. Analysis of the Spatial Organization of Pastures as a Contact Network, Implications for Potential Disease Spread and Biosecurity in Livestock, France, 2010.

    PubMed

    Palisson, Aurore; Courcoul, Aurélie; Durand, Benoit

    2017-01-01

    The use of pastures is part of common herd management practices for livestock animals, but contagion between animals located on neighbouring pastures is one of the major modes of infectious disease transmission between herds. At the population level, this transmission is strongly constrained by the spatial organization of pastures. The aim of this study was to answer two questions: (i) is the spatial configuration of pastures favourable to the spread of infectious diseases in France? (ii) would biosecurity measures allow decreasing this vulnerability? Based on GIS data, the spatial organization of pastures was represented using networks. Nodes were the 3,159,787 pastures reported in 2010 by the French breeders to claim the Common Agricultural Policy subsidies. Links connected pastures when the distance between them was below a predefined threshold. Premises networks were obtained by aggregating into a single node all the pastures under the same ownership. Although the pastures network was very fragmented when the distance threshold was short (1.5 meters, relevant for a directly-transmitted disease), it was not the case when the distance threshold was larger (500 m, relevant for a vector-borne disease: 97% of the nodes in the largest connected component). The premises network was highly connected as the largest connected component always included more than 83% of the nodes, whatever the distance threshold. Percolation analyses were performed to model the population-level efficacy of biosecurity measures. Percolation thresholds varied according to the modelled biosecurity measures and to the distance threshold. They were globally high (e.g. >17% of nodes had to be removed, mimicking the confinement of animals inside farm buildings, to obtain the disappearance of the large connected component). The network of pastures thus appeared vulnerable to the spread of diseases in France. Only a large acceptance of biosecurity measures by breeders would allow reducing this

  4. Static network analysis of a pork supply chain in Northern Germany-Characterisation of the potential spread of infectious diseases via animal movements.

    PubMed

    Büttner, Kathrin; Krieter, Joachim; Traulsen, Arne; Traulsen, Imke

    2013-07-01

    Transport of live animals is a major risk factor in the spread of infectious diseases between holdings. The present study analysed the pork supply chain of a producer community in Northern Germany. The structure of trade networks can be characterised by carrying out a network analysis. To identify holdings with a central position in this directed network of pig production, several parameters describing these properties were measured (in-degree, out-degree, ingoing and outgoing infection chain, betweenness centrality and ingoing and outgoing closeness centrality). To obtain the importance of the different holding types (multiplier, farrowing farms, finishing farms and farrow-to-finishing farms) within the pyramidal structure of the pork supply chain, centrality parameters were calculated for the entire network as well as for the individual holding types. Using these centrality parameters, two types of holdings could be identified. In the network studied, finishing and farrow-to-finishing farms were more likely to be infected due to the high number of ingoing trade contacts. Due to the high number of outgoing trade contacts multipliers and farrowing farms had an increased risk to spread a disease to other holdings. However, the results of the centrality parameters degree and infection chain were not always consistent, such that the indirect trade contacts should be taken into consideration to understand the real importance of a holding in spreading or contracting an infection. Furthermore, all calculated parameters showed a highly right-skewed distribution. Networks with such a degree distribution are considered to be highly resistant concerning the random removal of nodes. But by strategic removal of the most central holdings, e.g. by trade restrictions or selective vaccination or culling, the network structure can be changed efficiently and thus decompose into fragments. Such a fragmentation of the trade networks is of particular importance from an epidemiological

  5. 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.

  6. Contagious yawning in gelada baboons as a possible expression of empathy.

    PubMed

    Palagi, E; Leone, A; Mancini, G; Ferrari, P F

    2009-11-17

    Yawn contagion in humans has been proposed to be related to our capacity for empathy. It is presently unclear whether this capacity is uniquely human or shared with other primates, especially monkeys. Here, we show that in gelada baboons (Theropithecus gelada) yawning is contagious between individuals, especially those that are socially close, i.e., the contagiousness of yawning correlated with the level of grooming contact between individuals. This correlation persisted after controlling for the effect of spatial association. Thus, emotional proximity rather than spatial proximity best predicts yawn contagion. Adult females showed precise matching of different yawning types, which suggests a mirroring mechanism that activates shared representations. The present study also suggests that females have an enhanced sensitivity and emotional tuning toward companions. These findings are consistent with the view that contagious yawning reveals an emotional connection between individuals. This phenomenon, here demonstrated in monkeys, could be a building block for full-blown empathy.

  7. Contagious yawning in gelada baboons as a possible expression of empathy

    PubMed Central

    Palagi, E.; Leone, A.; Mancini, G.; Ferrari, P. F.

    2009-01-01

    Yawn contagion in humans has been proposed to be related to our capacity for empathy. It is presently unclear whether this capacity is uniquely human or shared with other primates, especially monkeys. Here, we show that in gelada baboons (Theropithecus gelada) yawning is contagious between individuals, especially those that are socially close, i.e., the contagiousness of yawning correlated with the level of grooming contact between individuals. This correlation persisted after controlling for the effect of spatial association. Thus, emotional proximity rather than spatial proximity best predicts yawn contagion. Adult females showed precise matching of different yawning types, which suggests a mirroring mechanism that activates shared representations. The present study also suggests that females have an enhanced sensitivity and emotional tuning toward companions. These findings are consistent with the view that contagious yawning reveals an emotional connection between individuals. This phenomenon, here demonstrated in monkeys, could be a building block for full-blown empathy. PMID:19889980

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

    PubMed

    Zumla, Alimuddin; Alagaili, Abdulaziz N; Cotten, Matthew; Azhar, Esam I

    2016-09-07

    Media and World Health Organization (WHO) attention on Zika virus transmission at the 2016 Rio Olympic Games and the 2015 Ebola virus outbreak in West Africa diverted the attention of global public health authorities from other lethal infectious diseases with epidemic potential. Mass gatherings such as the annual Hajj pilgrimage hosted by Kingdom of Saudi Arabia attract huge crowds from all continents, creating high-risk conditions for the rapid global spread of infectious diseases. The highly lethal Middle Eastern respiratory syndrome coronavirus (MERS-CoV) remains in the WHO list of top emerging diseases likely to cause major epidemics. The 2015 MERS-CoV outbreak in South Korea, in which 184 MERS cases including 33 deaths occurred in 2 months, that was imported from the Middle East by a South Korean businessman was a wake-up call for the global community to refocus attention on MERS-CoV and other emerging and re-emerging infectious diseases with epidemic potential. The international donor community and Middle Eastern countries should make available resources for, and make a serious commitment to, taking forward a "One Health" global network for proactive surveillance, rapid detection, and prevention of MERS-CoV and other epidemic infectious diseases threats.

  9. Adjuvants for foot-and-mouth disease virus vaccines: recent progress.

    PubMed

    Cao, Yimei

    2014-11-01

    Foot-and-mouth disease (FMD) is a highly contagious and rapidly spreading disease of cloven-hoofed animals. In most countries, animals are immunized with inactivated whole virus vaccines to control the spread of foot-and-mouth disease virus (FMDV); however, there are safety and efficacy (especially, cell-mediated immunity) concerns. Many efforts are currently devoted to the development of effective vaccines by combining the application of protective antigens together with the search for specific and targeting adjuvants that maximizes the immunogenicity with a desired immune response. In this review, we outline previous studies performed with both traditional adjuvants as well as the most promising new generation adjuvants such as ligands for Toll-like receptors (TLRs) or different cytokines, focusing mostly on their efficacy when used with FMD vaccine, and somewhat on mechanisms by which adjuvants mediate their effects.

  10. Analysis of Spatiotemporal Characteristics of Pandemic SARS Spread in Mainland China.

    PubMed

    Cao, Chunxiang; Chen, Wei; Zheng, Sheng; Zhao, Jian; Wang, Jinfeng; Cao, Wuchun

    2016-01-01

    Severe acute respiratory syndrome (SARS) is one of the most severe emerging infectious diseases of the 21st century so far. SARS caused a pandemic that spread throughout mainland China for 7 months, infecting 5318 persons in 194 administrative regions. Using detailed mainland China epidemiological data, we study spatiotemporal aspects of this person-to-person contagious disease and simulate its spatiotemporal transmission dynamics via the Bayesian Maximum Entropy (BME) method. The BME reveals that SARS outbreaks show autocorrelation within certain spatial and temporal distances. We use BME to fit a theoretical covariance model that has a sine hole spatial component and exponential temporal component and obtain the weights of geographical and temporal autocorrelation factors. Using the covariance model, SARS dynamics were estimated and simulated under the most probable conditions. Our study suggests that SARS transmission varies in its epidemiological characteristics and SARS outbreak distributions exhibit palpable clusters on both spatial and temporal scales. In addition, the BME modelling demonstrates that SARS transmission features are affected by spatial heterogeneity, so we analyze potential causes. This may benefit epidemiological control of pandemic infectious diseases.

  11. Analysis of Spatiotemporal Characteristics of Pandemic SARS Spread in Mainland China

    PubMed Central

    Cao, Chunxiang; Zheng, Sheng; Zhao, Jian; Wang, Jinfeng; Cao, Wuchun

    2016-01-01

    Severe acute respiratory syndrome (SARS) is one of the most severe emerging infectious diseases of the 21st century so far. SARS caused a pandemic that spread throughout mainland China for 7 months, infecting 5318 persons in 194 administrative regions. Using detailed mainland China epidemiological data, we study spatiotemporal aspects of this person-to-person contagious disease and simulate its spatiotemporal transmission dynamics via the Bayesian Maximum Entropy (BME) method. The BME reveals that SARS outbreaks show autocorrelation within certain spatial and temporal distances. We use BME to fit a theoretical covariance model that has a sine hole spatial component and exponential temporal component and obtain the weights of geographical and temporal autocorrelation factors. Using the covariance model, SARS dynamics were estimated and simulated under the most probable conditions. Our study suggests that SARS transmission varies in its epidemiological characteristics and SARS outbreak distributions exhibit palpable clusters on both spatial and temporal scales. In addition, the BME modelling demonstrates that SARS transmission features are affected by spatial heterogeneity, so we analyze potential causes. This may benefit epidemiological control of pandemic infectious diseases. PMID:27597972

  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

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Slaughter of poultry or other animals... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS GENERAL PROVISIONS § 71.14 Slaughter of poultry... to slaughter any diseased or exposed animals, including poultry, and the purchase of such...

  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

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Slaughter of poultry or other animals... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS GENERAL PROVISIONS § 71.14 Slaughter of poultry... to slaughter any diseased or exposed animals, including poultry, and the purchase of such...

  14. 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

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Slaughter of poultry or other animals... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS GENERAL PROVISIONS § 71.14 Slaughter of poultry... to slaughter any diseased or exposed animals, including poultry, and the purchase of such...

  15. 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

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Slaughter of poultry or other animals... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS GENERAL PROVISIONS § 71.14 Slaughter of poultry... to slaughter any diseased or exposed animals, including poultry, and the purchase of such...

  16. 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

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Slaughter of poultry or other animals... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS GENERAL PROVISIONS § 71.14 Slaughter of poultry... to slaughter any diseased or exposed animals, including poultry, and the purchase of such...

  17. 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…

  18. Changing sexual attitudes and behaviour in China: implications for the spread of HIV and other sexually transmitted diseases.

    PubMed

    Zhang, K; Li, D; Li, H; Beck, E J

    1999-10-01

    In Imperial China sexual behaviour was regarded as an indispensable activity to reach harmony with the universe, through the unity of the interaction of two opposing forces: yin and yang. Sexual intercourse was accepted when linked to procreation within a family context, while an individual's sexuality was not considered important. Homosexuality was tolerated although not advocated, while masturbation was denounced. Since the One Child Family and Open Door policies in the 1970s and the economic reforms of the 1980s, attitudes towards sexuality in China have changed. Premarital sex has become widely accepted among young people and people in China are now more tolerant toward extramarital sex. Nowadays young people consider that love should dominate marriage and the quality of an individual's sex life is currently more valued than it used to be. Attitudes towards masturbation have become more tolerant and though homosexuality has been hidden by society for a long time, in recent years it has begun to be considered as a legitimate lifestyle choice. Attitudes towards sex and sexual behaviour have become recognized as an individuals' responsibility as long as no offence occurs against society or the interests of other individuals, resulting in the recognition of diversity of sexual behaviour. As part of the changing attitudes to sex and sexual behaviour, heterosexual transmission is becoming the most important route of HIV transmission in China. This is complicated by the internal migration of an estimated 120 million labourers moving from the countryside to the cities as the result of economic reforms, most of whom are sexually active young men. Unless addressed directly, these factors may add to the estimated 300,000 HIV-infected Chinese, further fuelling an already rapidly spreading epidemic. The ramifications of the Chinese HIV epidemic will not only be felt within China, but also within the surrounding Asian countries thereby fuelling the HIV pandemic.

  19. Homosexuality and Pro-Gay Ideology as Pathogens? Implications of a Disease-Spread Lay Model for Understanding Anti-Gay Behaviors.

    PubMed

    Filip-Crawford, Gabrielle; Neuberg, Steven L

    2015-09-03

    Negative behaviors targeting gay men and lesbians range from violent physical assault to casting a vote against gay marriage, with very different implications for those targeted. Existing accounts of such actions, however, are unable to differentially predict specific anti-gay behaviors, leaving a large theoretical hole in the literature and hindering the design of effective interventions. We propose (a) that many sexually prejudiced laypersons conceptualize homosexuality and pro-gay ideology as "contaminants" analogous to infectious pathogens and (b) that anti-gay behaviors can thus be viewed as strategic attempts to prevent, contain, treat, or eradicate the "pathogens" of homosexuality and pro-gay ideology. By considering analogues to disease-spread processes (e.g., susceptibility of specific subpopulations, inoculation procedures, prevalence in the local environment, interconnections among community members), we derive novel predictions regarding the incidence and nature of anti-gay behaviors and provide leverage for creating more tailored interventions to reduce such discrimination.

  20. 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…

  1. 76 FR 52547 - Importation of Horses From Contagious Equine Metritis-Affected Countries

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... Animal and Plant Health Inspection Service 9 CFR Part 93 RIN 0579-AD31 Importation of Horses From Contagious Equine Metritis-Affected Countries AGENCY: Animal and Plant Health Inspection Service, USDA... comment period for an interim rule that amended the regulations regarding the testing requirements...

  2. Male yawning is more contagious than female yawning among chimpanzees (Pan troglodytes).

    PubMed

    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.

  3. Evidence for contagious behaviors in budgerigars (Melopsittacus undulatus): an observational study of yawning and stretching.

    PubMed

    Miller, Michael L; Gallup, Andrew C; Vogel, Andrea R; Vicario, Shannon M; Clark, Anne B

    2012-03-01

    Yawning is contagious in humans and some non-human primates. If there are social functions to contagious behaviors, such as yawning, they might occur in other highly social vertebrates. To investigate this possibility, we conducted an observational study of yawning and an associated behavior, stretching, in budgerigars (Melopsittacus undulatus), a social, flock-living parrot. Flock-housed budgerigars were videotaped for 1.5h at three time-blocks during the day (early morning, afternoon and early evening), and the times of all yawns and stretches for each bird were recorded. Both yawning and stretching were temporally clumped within sessions, but were uniformly distributed across the trials of a particular time-block. This suggests that clumping was not a result of circadian patterning and that both behaviors could be contagious. There was additional evidence of contagion in stretching, which occurred in two forms - a posterior-dorsal extension of either one foot or both feet. Birds that could have observed a conspecific stretch, and that then stretched themselves within 20s, replicated the form of the earlier stretch significantly more often than expected by chance. This study provides the first detailed description of temporal patterns of yawning under social conditions in a flock-living species as well as the first support for contagious yawning and stretching in a non-primate species in a natural context. Experimental evidence will be necessary to confirm the extent of contagion in either behavior.

  4. 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…

  5. Two contagious ectoparasites in an orphanage children in Nasr City, Cairo.

    PubMed

    Morsy, T A; el-Ela, R G; Morsy, A T; Nassar, M M; Khalaf, S A

    2000-12-01

    Lice and scabies are the main ectoparasites transmitted by contagious, particularly among children living in crowded areas. Examination of an orphanage children (both sex, 2-6 years old), showed infestation with head louse (64.1%), body louse (53.8%) and scabies (26.9%). The results were discussed on the light of the work done before.

  6. A Theory and Dynamic Model of Dyadic Interaction: Concerns, Appraisals, and Contagiousness in a Developmental Context

    ERIC Educational Resources Information Center

    Steenbeek, Henderien W.; van Geert, Paul L. C.

    2007-01-01

    A theory of the dynamics of dyadic interaction is presented, based on the concepts of "concern" (i.e., intentions, goals, and interests), "appraisal" and "contagiousness." Differences between children who participate in a specific interaction are linked to differences in social competence and social power. An overview is given of the social…

  7. Contagious itch: what we know and what we would like to know

    PubMed Central

    Schut, C.; Grossman, S.; Gieler, U.; Kupfer, J.; Yosipovitch, G.

    2015-01-01

    All humans experience itch in the course of their life. Even a discussion on the topic of itch or seeing people scratch can evoke the desire to scratch. These events are coined “contagious itch” and are very common. We and others have shown that videos showing people scratching and pictures of affected skin or insects can induce itch in healthy persons and chronic itch patients. In our studies, patients with atopic dermatitis (AD) were more susceptible to visual itch cues than healthy. Also, personality traits like agreeableness and public self-consciousness were associated with induced scratching in skin patients, while neuroticism correlated with induced itch in healthy subjects. The underlying course of contagious itch is not yet fully understood. It is hypothesized that there are human mirror neurons that are active when we imitate actions and/or negative affect. Until now, there has been only limited data on the mechanisms of brain activation in contagious itch though. We have barely begun to understand the underlying physiological reactions and the triggering factors of this phenomenon. We summarize what we currently know about contagious itch and provide some suggestions what future research should focus on. PMID:25717300

  8. 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…

  9. Development of a Discrete Spatial-Temporal SEIR Simulator for Modeling Infectious Diseases

    SciTech Connect

    McKenna, S.A.

    2000-11-01

    Multiple techniques have been developed to model the temporal evolution of infectious diseases. Some of these techniques have also been adapted to model the spatial evolution of the disease. This report examines the application of one such technique, the SEIR model, to the spatial and temporal evolution of disease. Applications of the SEIR model are reviewed briefly and an adaptation to the traditional SEIR model is presented. This adaptation allows for modeling the spatial evolution of the disease stages at the individual level. The transmission of the disease between individuals is modeled explicitly through the use of exposure likelihood functions rather than the global transmission rate applied to populations in the traditional implementation of the SEIR model. These adaptations allow for the consideration of spatially variable (heterogeneous) susceptibility and immunity within the population. The adaptations also allow for modeling both contagious and non-contagious diseases. The results of a number of numerical experiments to explore the effect of model parameters on the spread of an example disease are presented.

  10. B7-H3 and B7x are highly expressed in human prostate cancer and associated with disease spread and poor outcome

    PubMed Central

    Zang, Xingxing; Thompson, R. Houston; Al-Ahmadie, Hikmat A.; Serio, Angel M.; Reuter, Victor E.; Eastham, James A.; Scardino, Peter T.; Sharma, Padmanee; Allison, James P.

    2007-01-01

    B7-H3 and B7x are recently discovered members of the B7-CD28 family thought to dampen peripheral immune responses via negative costimulation. We evaluated their potential expression in human prostate cancer using a large cohort of patients with 7 years of follow-up. We identified 823 patients with tissue available treated with radical prostatectomy between 1985 and 2003. Immunohistochemistry was performed on tissue microarray sections using anti-B7-H3 and -B7x. The percentage and intensity of immunoreactivity by tumor cells were blindly evaluated by two urological pathologists, and outcome analyses were conducted. Both B7-H3 and B7x were highly expressed; 93% and 99% of tumors had aberrant expression, respectively. The median percentage of tumor cells staining positive was 80% for each molecule. Strong intensity for B7-H3 and B7x was noted in 212 (26%) and 120 (15%) patients, respectively. Patients with strong intensity for B7-H3 and B7x were significantly more likely to have disease spread at time of surgery (P < 0.001 and P = 0.005, respectively). Additionally, patients with strong intensity for B7-H3 and B7x were at significantly increased risk of clinical cancer recurrence (P < 0.001 and P = 0.005) and cancer-specific death (P = 0.004 and P = 0.04, respectively). To our knowledge, we present the largest investigation of B7 family molecules in a human malignancy and a previously undescribed evaluation of B7x in prostate cancer. B7-H3 and B7x are abundantly expressed in prostate cancer and associated with disease spread and poor outcome. Given the proposed immune-inhibitory mechanisms of B7-H3 and B7x, these molecules represent attractive targets for therapeutic manipulation in prostate cancer. PMID:18042703

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

    NASA Astrophysics Data System (ADS)

    Mikkelsen, T.; Alexandersen, S.; Astrup, P.; Champion, H. J.; Donaldson, A. I.; Dunkerley, F. N.; Gloster, J.; Sørensen, J. H.; Thykier-Nielsen, S.

    2003-11-01

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed domesticated and wild animals. The highly contagious nature of FMD is a reflection of the wide range of host species, the enormous quantities of virus liberated by infected animals, the range of excretions and secretions which can be infectious, the stability of the virus in the environment, the multiplicity of routes of infection and the very small doses of the virus that can initiate infection. One of the mechanisms of spread is the carriage of droplets and droplet nuclei exhaled in the breath of infected animals. Such spread can be rapid and extensive, and it is known in certain circumstances to have transmitted disease over a distance of several hundred kilometres. During the 2001 FMD epidemic in the United Kingdom (UK), atmospheric dispersion models were applied in real time in order to assess the potential for atmospheric dispersion of the disease. The operational value of such modelling is primarily to identify premises which may have been exposed so that the human resources for surveillance and disease control purposes are employed most effectively.

    The paper describes the combined modelling techniques and presents the results obtained of detailed analyses performed during the early stages of the UK 2001 epidemic. This paper investigates the potential for disease spread in relation to two outbreaks (Burnside Farm, Heddon-on-the-Wall and Prestwick Hall Farm, Ponteland, Northumberland). A separate paper (Gloster et al., 2002) provides a more detailed analysis of the airborne disease transmission in the vicinity of Burnside Farm.

    The combined results are consistent with airborne transmission of disease to livestock in the Heddon-on-the-Wall area. Local topography may have played a significant role in influencing the pattern of disease spread.

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

    NASA Astrophysics Data System (ADS)

    Mikkelsen, T.; Alexandersen, S.; Astrup, P.; Champion, H. J.; Donaldson, A. I.; Dunkerley, F. N.; Gloster, J.; Sørensen, J. H.; Thykier-Nielsen, S.

    2003-02-01

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed domesticated and wild animals. The highly contagious nature of FMD is a reflection of the wide range of host species, the enormous quantities of virus liberated by infected animals, the range of excretions and secretions which can be infectious, the stability of the virus in the environment, the multiplicity of routes of infection and the very small doses of the virus that can initiate infection. One of the mechanisms of spread is the carriage of droplets and droplet nuclei exhaled in the breath of infected animals. Such spread can be rapid and extensive, and it is known in certain circumstances to have transmitted disease over a distance of several hundred kilometres. During the 2001 FMD epidemic in the United Kingdom (UK), atmospheric dispersion models were applied in real time in order to assess the potential for atmospheric dispersion of the disease. The operational value of such modelling is primarily to identify premises which may have been exposed so that the human resources for surveillance and disease control purposes are employed most effectively. The paper describes the combined modelling techniques and presents the results obtained of detailed analyses performed during the early stages of the UK 2001 epidemic. This paper investigates the potential for disease spread in relation to two outbreaks (Burnside Farm, Heddon-on-the-Wall and Prestwick Hall Farm, Ponteland, Northumberland). A separate paper (Gloster et al., 2002) provides a more detailed analysis of the airborne disease transmission in the vicinity of Burnside Farm. The combined results are consistent with airborne transmission of disease to livestock in the Heddon-on-the Wall area. Local topography may have played a significant role in influencing the pattern of disease spread.

  13. Diffusion tensor imaging analysis of sequential spreading of disease in amyotrophic lateral sclerosis confirms patterns of TDP-43 pathology.

    PubMed

    Kassubek, Jan; Müller, Hans-Peter; Del Tredici, Kelly; Brettschneider, Johannes; Pinkhardt, Elmar H; Lulé, Dorothée; Böhm, Sarah; Braak, Heiko; Ludolph, Albert C

    2014-06-01

    Diffusion tensor imaging can identify amyotrophic lateral sclerosis-associated patterns of brain alterations at the group level. Recently, a neuropathological staging system for amyotrophic lateral sclerosis has shown that amyotrophic lateral sclerosis may disseminate in a sequential regional pattern during four disease stages. The objective of the present study was to apply a new methodological diffusion tensor imaging-based approach to automatically analyse in vivo the fibre tracts that are prone to be involved at each neuropathological stage of amyotrophic lateral sclerosis. Two data samples, consisting of 130 diffusion tensor imaging data sets acquired at 1.5 T from 78 patients with amyotrophic lateral sclerosis and 52 control subjects; and 55 diffusion-tensor imaging data sets at 3.0 T from 33 patients with amyotrophic lateral sclerosis and 22 control subjects, were analysed by a tract of interest-based fibre tracking approach to analyse five tracts that become involved during the course of amyotrophic lateral sclerosis: the corticospinal tract (stage 1); the corticorubral and the corticopontine tracts (stage 2); the corticostriatal pathway (stage 3); the proximal portion of the perforant path (stage 4); and two reference pathways. The statistical analyses of tracts of interest showed differences between patients with amyotrophic lateral sclerosis and control subjects for all tracts. The significance level of the comparisons at the group level was lower, the higher the disease stage with corresponding involved fibre tracts. Both the clinical phenotype as assessed by the amyotrophic lateral sclerosis functional rating scale-revised and disease duration correlated significantly with the resulting staging scheme. In summary, the tract of interest-based technique allowed for individual analysis of predefined tract structures, thus making it possible to image in vivo the disease stages in amyotrophic lateral sclerosis. This approach can be used not only for

  14. Poleward Expansion of the White-Footed Mouse (Peromyscus leucopus) under Climate Change: Implications for the Spread of Lyme Disease

    PubMed Central

    Roy-Dufresne, Emilie; Logan, Travis; Simon, Julie A.; Chmura, Gail L.; Millien, Virginie

    2013-01-01

    The white-footed mouse (Peromyscus leucopus) is an important reservoir host for Borrelia burgdorferi, the pathogen responsible for Lyme disease, and its distribution is expanding northward. We used an Ecological Niche Factor Analysis to identify the climatic factors associated with the distribution shift of the white-footed mouse over the last 30 years at the northern edge of its range, and modeled its current and potential future (2050) distributions using the platform BIOMOD. A mild and shorter winter is favouring the northern expansion of the white-footed mouse in Québec. With more favorable winter conditions projected by 2050, the distribution range of the white-footed mouse is expected to expand further northward by 3° latitude. We also show that today in southern Québec, the occurrence of B. burgdorferi is associated with high probability of presence of the white-footed mouse. Changes in the distribution of the white-footed mouse will likely alter the geographical range of B. burgdorferi and impact the public health in northern regions that have yet to be exposed to Lyme disease. PMID:24260464

  15. 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].

  16. 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

    2015-11-27

    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.

  17. Origin and spread of the 1278insTATC mutation causing Tay-Sachs disease in Ashkenazi Jews: genetic drift as a robust and parsimonious hypothesis.

    PubMed

    Frisch, Amos; Colombo, Roberto; Michaelovsky, Elena; Karpati, Mazal; Goldman, Boleslaw; Peleg, Leah

    2004-03-01

    The 1278insTATC is the most prevalent beta-hexosaminidase A ( HEXA) gene mutation causing Tay-Sachs disease (TSD), one of the four lysosomal storage diseases (LSDs) occurring at elevated frequencies among Ashkenazi Jews (AJs). To investigate the genetic history of this mutation in the AJ population, a conserved haplotype (D15S981:175-D15S131:240-D15S1050:284-D15S197:144-D15S188:418) was identified in 1278insTATC chromosomes from 55 unrelated AJ individuals (15 homozygotes and 40 heterozygotes for the TSD mutation), 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 insertion was found to be 40+/-12 generations (95% confidence interval: 30-50 generations), so that the most recent common ancestor of the mutation-bearing chromosomes would date to the 8th-9th century. This corresponds with the demographic expansion of AJs in central Europe, following the founding of the Ashkenaz settlement in the early Middle Ages. The results are consistent with the geographic distribution of the main TSD mutation, 1278insTATC being more common in central Europe, and with the coalescent times of mutations causing two other LSDs, Gaucher disease and mucolipidosis type IV. Evidence for the absence of a determinant positive selection (heterozygote advantage) over the mutation is provided by a comparison between the estimated age of 1278insTATC and the probability of the current AJ frequency of the mutant allele as a function of its age, calculated by use of a branching-process model. Therefore, the founder effect in a rapidly expanding population arising from a bottleneck provides a robust parsimonious hypothesis explaining the spread of 1278insTATC-linked TSD in AJ individuals.

  18. 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

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

    PubMed

    Kifle, Yimer Wasihun; Goeyvaerts, Nele; Van Kerckhove, Kim; Willem, Lander; Kucharski, Adam; 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.

  20. Contagious agalactia due to Mycoplasma spp. in small dairy ruminants: epidemiology and prospects for diagnosis and control.

    PubMed

    Gómez-Martín, Angel; Amores, Joaquín; Paterna, Ana; De la Fe, Christian

    2013-10-01

    Contagious agalactia (CA) is a serious disease of small dairy ruminants that has a substantial economic impact on the goat and sheep milk industries. The main aetiological agent of the disease is Mycoplasma agalactiae, although other species, such as Mycoplasma mycoides subsp. capri, Mycoplasma capricolum subsp. capricolum and Mycoplasma putrefaciens, are pathogenic in goats. There are two clinical-epidemiological states of CA in sheep and goats; herds and flocks may exhibit outbreaks of CA or may be chronically infected, the latter with a high incidence of subclinical mastitis and only occasional clinical cases. The complex epidemiology of CA is related to the genetic characteristics and mechanisms of molecular variation of the Mycoplasma spp. involved, along with presence of CA-mycoplasmas in wild ruminant species. In goats, the situation is particularly complex and asymptomatic carriers have been detected in chronically infected herds. The coexistence of other non-pathogenic mycoplasmas in the herd further complicates the diagnosis of CA and the design of efficient strategies to control the disease. Routes of infection, such as the venereal route, may be involved in the establishment of chronic infection in herds. Current challenges include the need for improved diagnostic methods for detection of chronic and subclinical infections and for the design of more efficient vaccines.

  1. Plagued by kindness: contagious sympathy in Shakespearean drama.

    PubMed

    Langley, Eric

    2011-12-01

    This article considers Shakespeare's metaphors of transmission, contagion and infection in the light of period plague tracts, medical treatises and plague time literature. The author demonstrates how period conceptions of disease are predicated upon a notion of sympathetic transference and, consequently, how kindness, likeness and communication between characters in Shakespearean drama are complicated and fraught with period specific anxiety. This article situates Shakespearean literary texts within a precise historical and medical moment, considering how scientific conceptions contaminate dramatic text.

  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

  3. 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.

  4. Development of an improved vaccine for contagious bovine pleuropneumonia: an African perspective on challenges and proposed actions.

    PubMed

    Jores, Joerg; Mariner, Jeffrey C; Naessens, Jan

    2013-12-20

    Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides (Mmm) is an economically very important cattle disease in sub-Saharan Africa. CBPP impacts animal health and poverty of livestock-dependent people through decreased animal productivity, reduced food supply, and the cost of control measures. CBPP is a barrier to trade in many African countries and this reduces the value of livestock and the income of many value chain stakeholders. The presence of CBPP also poses a constant threat to CBPP-free countries and creates costs in terms of the measures necessary to ensure the exclusion of disease. This opinion focuses on the biomedical research needed to foster the development of better control measures for CBPP. We suggest that different vaccine development approaches are followed in parallel. Basic immunology studies and systematic OMICs studies will be necessary in order to identify the protective arms of immunity and to shed more light on the pathogenicity mechanisms in CBPP. Moreover a robust challenge model and a close collaboration with African research units will be crucial to foster and implement a new vaccine for the progressive control of this cattle plague.

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

    PubMed Central

    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

    2011-01-01

    Purpose 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. Results 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. Conclusions 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. PMID:20592016

  6. One-Health Simulation Modelling: A Case Study of Influenza Spread between Human and Swine Populations using NAADSM.

    PubMed

    Dorjee, S; Revie, C W; Poljak, Z; McNab, W B; Sanchez, J

    2016-02-01

    The circulation of zoonotic influenza A viruses including pH1N1 2009 and H5N1 continue to present a constant threat to animal and human populations. Recently, an H3N2 variant spread from pigs to humans and between humans in limited numbers. Accordingly, this research investigated a range of scenarios of the transmission dynamics of pH1N1 2009 virus at the swine-human interface while accounting for different percentages of swine workers initially immune. Furthermore, the feasibility of using NAADSM (North American Animal Disease Spread Model) applied as a one-health simulation model was assessed. The study population included 488 swine herds and 29, 707 households of people within a county in Ontario, Canada. Households were categorized as follows: (i) rural households with swine workers, (ii) rural households without swine workers, and (iii) urban households without swine workers. Forty-eight scenarios were investigated, based on the combination of six scenarios around the transmissibility of the virus at the interface and four vaccination coverage levels of swine workers (0-60%), all under two settings of either swine or human origin of the virus. Outcomes were assessed in terms of stochastic 'die-out' fraction, size and time to peak epidemic day, overall size and duration of the outbreaks. The modelled outcomes indicated that minimizing influenza transmissibility at the interface and targeted vaccination of swine workers had significant beneficial effects. Our results indicate that NAADSM can be used as a framework to model the spread and control of contagious zoonotic diseases among animal and human populations, under certain simplifying assumptions. Further evaluation of the model is required. In addition to these specific findings, this study serves as a benchmark that can provide useful input to a future one-health influenza modelling studies. Some pertinent information gaps were also identified. Enhanced surveillance and the collection of high

  7. 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

  8. Characterization of the in vitro core surface proteome of Mycoplasma mycoides subsp. mycoides, the causative agent of contagious bovine pleuropneumonia.

    PubMed

    Krasteva, Ivanka; Liljander, Anne; Fischer, Anne; Smith, David G E; Inglis, Neil F; Scacchia, Massimo; Pini, Attilio; Jores, Joerg; Sacchini, Flavio

    2014-01-10

    Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides (Mmm) is a severe cattle disease, present in many countries in sub-Saharan Africa. The development of improved diagnostic tests and vaccines for CBPP control remains a research priority. Polyacrylamide gel electrophoresis and mass spectrometry were used to characterize the Triton X-114 soluble proteome of nine Mmm strains isolated from Europe or Africa. Of a total of 250 proteins detected, 67 were present in all strains investigated. Of these, 44 were predicted to be lipoproteins or cytoplasmic membrane-associated proteins and are thus likely to be members of the core in vitro surface membrane-associated proteome of Mmm. Moreover, the presence of all identified proteins in other ruminant Mycoplasma pathogens were investigated. Two proteins of the core proteome were identified only in other cattle pathogens of the genus Mycoplasma pointing towards a role in host-pathogen interactions. The data generated will facilitate the identification and prioritization of candidate Mycoplasma antigens for improved control measures, as it is likely that surface-exposed membrane proteins will include those that are involved in host-pathogen interactions.

  9. Hierarchical mechanisms of spatially contagious seed dispersal in complex seed-disperser networks.

    PubMed

    Fedriani, José M; Wiegand, Thorsten

    2014-02-01

    Intra- and interspecific spatially contagious seed dispersal has far-reaching implications for plant recruitment, distribution, and community assemblage. However, logistical and analytical limitations have curtailed our understanding concerning the mechanisms and resulting spatial patterns of contagious seed dispersal in most systems and, especially, in complex seed-disperser networks. We investigated mechanisms of seed aggregation using techniques of spatial point pattern analysis and extensive data sets on mutispecific endozoochorous seed rain generated by five frugivorous mammals in three Mediterranean shrublands over two seasons. Our novel analytical approach revealed three hierarchical and complementary mechanisms of seed aggregation acting at different levels (fecal samples, seeds, pairs of seed species) and spatial scales. First, the three local guilds of frugivores tended to deliver their feces highly aggregated at small and intermediate spatial scales, and the overall pattern of fecal delivery could be described well by a nested double-cluster Thomas process. Second, once the strong observed fecal aggregation was accounted for, the distribution of mammal feces containing seeds was clustered within the pattern of all feces (i.e., with and without seeds), and the density of fecal samples containing seeds was higher than expected around other feces containing seeds in two out of the three studied seed-disperser networks. Finally, at a finer level, mark correlation analyses revealed that for some plant species pairs, the number of dispersed seeds was positively associated either at small or large spatial scales. Despite the relatively invariant patterning of nested double-clustering, some attributes of endozoochorous seed rain (e.g., intensity, scales of aggregation) were variable among study sites due to changes in the ecological context in which seeds and their dispersers interact. Our investigation disentangles for the first time the hierarchy of synergic

  10. 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.

  11. 25 CFR 700.723 - Control of livestock disease and parasites.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 have... responsible permittee in accordance with applicable laws....

  12. An international collaborative study to determine the prevalence of contagious caprine pleuropneumonia by monoclonal antibody-based cELISA

    PubMed Central

    2014-01-01

    Background Few serological tests are available for detecting antibodies against Mycoplasma capricolum subsp. capripneumoniae, the causal agent of contagious caprine pleuropneumonia (CCPP). The complement fixation test, the test prescribed for international trade purposes, uses a crude antigen that cross-reacts with all the other mycoplasma species of the “mycoides cluster” frequently infecting goat herds. The lack of a more specific test has been a real obstacle to the evaluation of the prevalence and economic impact of CCPP worldwide. A new competitive ELISA kit for CCPP, based on a previous blocking ELISA, was formatted at CIRAD and used to evaluate the prevalence of CCPP in some regions of Kenya, Ethiopia, Mauritius, Tajikistan and Pakistan in an international collaborative study. Results The strict specificity of the test was confirmed in CCPP-free goat herds exposed to other mycoplasma species of the “mycoides cluster”. Prevalence studies were performed across the enzootic range of the disease in Africa and Asia. Seroprevalence was estimated at 14.6% in the Afar region of Ethiopia, whereas all the herds presented for CCPP vaccination in Kenya tested positive (individual seroprevalence varied from 6 to 90% within each herd). In Mauritius, where CCPP emerged in 2009, nine of 62 herds tested positive. In Central Asia, where the disease was confirmed only recently, no positive animals were detected in the Wakhan District of Afghanistan or across the border in neighboring areas of Tajikistan, whereas seroprevalence varied between 2.7% and 44.2% in the other districts investigated and in northern Pakistan. The test was also used to monitor seroconversion in vaccinated animals. Conclusions This newly formatted CCPP cELISA kit has retained the high specificity of the original kit. It can therefore be used to evaluate the prevalence of CCPP in countries or regions without vaccination programs. It could also be used to monitor the efficacy of vaccination

  13. 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

  14. Mirror neuron activity during contagious yawning--an fMRI study.

    PubMed

    Haker, Helene; Kawohl, Wolfram; Herwig, Uwe; Rössler, Wulf

    2013-03-01

    Yawning is contagious. However, little research has been done to elucidate the neuronal representation of this phenomenon. Our study objective was to test the hypothesis that the human mirror neuron system (MNS) is activated by visually perceived yawning. We used functional magnetic resonance imaging to assess brain activity during contagious yawning (CY). Signal-dependent changes in blood oxygen levels were compared when subjects viewed videotapes of yawning faces as opposed to faces with a neutral expression. In response to yawning, subjects showed unilateral activation of their Brodmann's area 9 (BA 9) portion of the right inferior frontal gyrus, a region of the MNS. In this way, two individuals could share physiological and associated emotional states based on perceived motor patterns. This is one component of empathy (motor empathy) that underlies the development of cognitive empathy. The BA 9 is reportedly active in tasks requiring mentalizing abilities. Our results emphasize the connection between the MNS and higher cognitive empathic functions, including mentalizing. We conclude that CY is based on a functional substrate of empathy.

  15. 2SI2R rumor spreading model in homogeneous networks

    NASA Astrophysics Data System (ADS)

    Wang, Jiajia; Zhao, Laijun; Huang, Rongbing

    2014-11-01

    Similarities exist between the rumor spreading and the infectious disease transmission. Some researches on the disease spreading involve two or more diseases which are cross-infection propagation. Similarly, two or several kinds of rumors may spread at the same time. In this paper, we study a rumor spreading model called 2SI2R model, in which two types of rumors spread simultaneously among the crowd. Derived from mean-field equations, the dynamics of the 2SI2R rumor spreading model in homogeneous networks is elucidated. Employing the method on infectious diseases, the basic reproduction number, the stability of the disease-free equilibrium, and the final size of rumor are investigated and discussed. In the numerical simulation part, the interaction of two rumors and the impact of different parameters on the rumor spreading are discussed.

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

    PubMed Central

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

    2015-01-01

    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

  17. 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.

  18. 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…

  19. The spreading of disorder.

    PubMed

    Keizer, Kees; Lindenberg, Siegwart; Steg, Linda

    2008-12-12

    Imagine that the neighborhood you are living in is covered with graffiti, litter, and unreturned shopping carts. Would this reality cause you to litter more, trespass, or even steal? A thesis known as the broken windows theory suggests that signs of disorderly and petty criminal behavior trigger more disorderly and petty criminal behavior, thus causing the behavior to spread. This may cause neighborhoods to decay and the quality of life of its inhabitants to deteriorate. For a city government, this may be a vital policy issue. But does disorder really spread in neighborhoods? So far there has not been strong empirical support, and it is not clear what constitutes disorder and what may make it spread. We generated hypotheses about the spread of disorder and tested them in six field experiments. We found that, when people observe that others violated a certain social norm or legitimate rule, they are more likely to violate other norms or rules, which causes disorder to spread.

  20. Flame spread across liquids

    NASA Technical Reports Server (NTRS)

    Ross, Howard D.; Miller, Fletcher; Schiller, David; Sirignano, William

    1995-01-01

    Recent reviews of our understanding of flame spread across liquids show that there are many unresolved issues regarding the phenomenology and causal mechanisms affecting ignition susceptibility, flame spread characteristics, and flame spread rates. One area of discrepancy is the effect of buoyancy in both the uniform and pulsating spread regimes. The approach we have taken to resolving the importance of buoyancy for these flames is: (1) normal gravity (1g) and microgravity (micro g) experiments; and (2) numerical modeling at different gravitational levels. Of special interest to this work, as discussed at the previous workshop, is the determination of whether, and under what conditions, pulsating spread occurs in micro g. Microgravity offers a unique ability to modify and control the gas-phase flow pattern by utilizing a forced air flow over the pool surface.

  1. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 11. Use of antiseptics and sanitizers in community settings and issues of hand hygiene compliance in health care and food industries.

    PubMed

    Todd, Ewen C D; Greig, Judy D; Michaels, Barry S; Bartleson, Charles A; Smith, Debra; Holah, John

    2010-12-01

    Hand washing with soap is a practice that has long been recognized as a major barrier to the spread of disease in food production, preparation, and service and in health care settings, including hospitals, child care centers, and elder care facilities. Many of these settings present multiple opportunities for spread of pathogens within at-risk populations, and extra vigilance must be applied. Unfortunately, hand hygiene is not always carried out effectively, and both enteric and respiratory diseases are easily spread in these environments. Where water is limited or frequent hand hygiene is required on a daily basis, such as for many patients in hospitals and astronauts in space travel, instant sanitizers or sanitary wipes are thought to be an effective way of preventing contamination and spread of organisms among coworkers and others. Most concerns regarding compliance are associated with the health care field, but the food industry also must be considered. Specific reasons for not washing hands at appropriate times are laziness, time pressure, inadequate facilities and supplies, lack of accountability, and lack of involvement by companies, managers, and workers in supporting proper hand washing. To facilitate improvements in hand hygiene, measurement of compliant and noncompliant actions is necessary before implementing any procedural changes. Training alone is not sufficient for long-lasting improvement. Multiactivity strategies also must include modification of the organization culture to encourage safe hygienic practices, motivation of employees willing to use peer pressure on noncompliant coworkers, a reward and/or penalty system, and an operational design that facilitates regular hand hygiene.

  2. Unprecedented Disease-Related Coral Mortality in Southeastern Florida

    PubMed Central

    Precht, William F.; Gintert, Brooke E.; Robbart, Martha L.; Fura, Ryan; van Woesik, Robert

    2016-01-01

    Anomalously high water temperatures, associated with climate change, are increasing the global prevalence of coral bleaching, coral diseases, and coral-mortality events. Coral bleaching and disease outbreaks are often inter-related phenomena, since many coral diseases are a consequence of opportunistic pathogens that further compromise thermally stressed colonies. Yet, most coral diseases have low prevalence (<5%), and are not considered contagious. By contrast, we document the impact of an extremely high-prevalence outbreak (61%) of white-plague disease at 14 sites off southeastern Florida. White-plague disease was observed near Virginia Key, Florida, in September 2014, and after 12 months had spread 100 km north and 30 km south. The disease outbreak directly followed a high temperature coral-bleaching event and affected at least 13 coral species. Eusmilia fastigiata, Meandrina meandrites, and Dichocoenia stokesi were the most heavily impacted coral species, and were reduced to <3% of their initial population densities. A number of other coral species, including Colpophyllia natans, Pseudodiploria strigosa, Diploria labyrinthiformis, and Orbicella annularis were reduced to <25% of their initial densities. The high prevalence of disease, the number of susceptible species, and the high mortality of corals affected suggests this disease outbreak is arguably one of the most lethal ever recorded on a contemporary coral reef. PMID:27506875

  3. Unprecedented Disease-Related Coral Mortality in Southeastern Florida

    NASA Astrophysics Data System (ADS)

    Precht, William F.; Gintert, Brooke E.; Robbart, Martha L.; Fura, Ryan; van Woesik, Robert

    2016-08-01

    Anomalously high water temperatures, associated with climate change, are increasing the global prevalence of coral bleaching, coral diseases, and coral-mortality events. Coral bleaching and disease outbreaks are often inter-related phenomena, since many coral diseases are a consequence of opportunistic pathogens that further compromise thermally stressed colonies. Yet, most coral diseases have low prevalence (<5%), and are not considered contagious. By contrast, we document the impact of an extremely high-prevalence outbreak (61%) of white-plague disease at 14 sites off southeastern Florida. White-plague disease was observed near Virginia Key, Florida, in September 2014, and after 12 months had spread 100 km north and 30 km south. The disease outbreak directly followed a high temperature coral-bleaching event and affected at least 13 coral species. Eusmilia fastigiata, Meandrina meandrites, and Dichocoenia stokesi were the most heavily impacted coral species, and were reduced to <3% of their initial population densities. A number of other coral species, including Colpophyllia natans, Pseudodiploria strigosa, Diploria labyrinthiformis, and Orbicella annularis were reduced to <25% of their initial densities. The high prevalence of disease, the number of susceptible species, and the high mortality of corals affected suggests this disease outbreak is arguably one of the most lethal ever recorded on a contemporary coral reef.

  4. Flame Spread Across Liquids

    NASA Technical Reports Server (NTRS)

    Ross, Howard D.; Miller, Fletcher J.; Sirignano, William A.; Schiller, David

    1997-01-01

    The principal goal of our recent research on flame spread across liquid pools is the detailed identification of the mechanisms that control the rate and nature of flame spread when the liquid pool is initially at an isothermal bulk temperature that is below the fuel's flash point temperature. In our project, we specialize the subject to highlight the roles of buoyancy-related processes regarding the mechanisms of flame spread, an area of research cited recently by Linan and Williams as one that needs further attention and which microgravity (micro-g) experiments could help to resolve. Toward resolving the effects of buoyancy on this flame spread problem, comparisons - between 1-g and micro-g experimental observations, and between model predictions and experimental data at each of these gravitational levels - are extensively utilized. The present experimental and computational foundation is presented to support identification of the mechanisms that control flame spread in the pulsating flame spread regime for which long-duration, micro-g flame spread experiments have been conducted aboard a sounding rocket.

  5. Effect of "Pink Eye" Label on Parents' Intent to Use Antibiotics and Perceived Contagiousness.

    PubMed

    Scherer, Laura D; Finan, Caitlin; Simancek, Dalton; Finkelstein, Jerome I; Tarini, Beth A

    2016-06-01

    Parents of children who presented for a pediatrics appointment responded to a clinical vignette that described a child with symptoms consistent with acute viral conjunctivitis. In a 2 × 2 randomized survey design, the physician in the vignette either used the term "pink eye" or "eye infection" to describe the symptoms, and either told parents that antibiotics are likely ineffective at treating the symptoms or did not discuss effectiveness. When the symptoms were referred to as "pink eye," parents remained interested in antibiotics, despite being informed about their ineffectiveness. By contrast, when the symptoms were referred to as an "eye infection," information about antibiotic ineffectiveness significantly reduced interest, Mdiff = 1.63, P < .001. Parents who received the "pink eye" label also thought that the symptoms were more contagious and were less likely to believe that their child could go to child care, compared with parents who received the "eye infection" label, Mdiff = 0.37, P = .38.

  6. An Observational Investigation of Behavioral Contagion in Common Marmosets (Callithrix jacchus): Indications for Contagious Scent-Marking

    PubMed Central

    Massen, Jorg J. M.; Šlipogor, Vedrana; Gallup, Andrew C.

    2016-01-01

    Behavioral contagion is suggested to promote group coordination that may facilitate activity transitions, increased vigilance, and state matching. Apart from contagious yawning, however, very little attention has been given to this phenomenon, and studies on contagious yawning in primates have so far only focused on Old World monkeys and apes. Here we studied behavioral contagion in common marmosets, a species for which group coordination and vigilance are paramount. In particular, we investigated the contagiousness of yawning, stretching, scratching, tongue protrusion, gnawing, and scent-marking. We coded these behaviors from 14 adult marmosets, from two different social groups. During testing sessions, animals were separated into groups of four individuals for 20-min observation periods, across three distinct diurnal time points (morning, midday, and afternoon) to test for circadian patterns. We observed almost no yawning (0.12 yawns/h) and very little stretching behavior. For all other behaviors, which were more common, we found several temporal and inter-individual differences (i.e., sex, age, dominance status) predictive of these responses. Moreover, we found that gnawing and scent-marking, which almost always co-occurred as a fixed-action pattern, were highly temporally clustered within observation sessions. We discuss the relative absence of yawning in marmosets as well as the possible function of contagious scent-marking, and provide suggestions for future research into the proximate and ultimate functions of these behaviors in marmosets. PMID:27563294

  7. Modeling the Spread of Ebola

    PubMed Central

    Do, Tae Sug; Lee, Young S.

    2016-01-01

    Objectives This study aims to create a mathematical model to better understand the spread of Ebola, the mathematical dynamics of the disease, and preventative behaviors. Methods An epidemiological model is created with a system of nonlinear differential equations, and the model examines the disease transmission dynamics with isolation through stability analysis. All parameters are approximated, and results are also exploited by simulations. Sensitivity analysis is used to discuss the effect of intervention strategies. Results The system has only one equilibrium point, which is the disease-free state (S,L,I,R,D) = (N,0,0,0,0). If traditional burials of Ebola victims are allowed, the possible end state is never stable. Provided that safe burial practices with no traditional rituals are followed, the endemic-free state is stable if the basic reproductive number, R0, is less than 1. Model behaviors correspond to empirical facts. The model simulation agrees with the data of the Nigeria outbreak in 2004: 12 recoveries, eight deaths, Ebola free in about 3 months, and an R0 value of about 2.6 initially, which signifies swift spread of the infection. The best way to reduce R0 is achieving the speedy net effect of intervention strategies. One day's delay in full compliance with building rings around the virus with isolation, close observation, and clear education may double the number of infected cases. Conclusion The model can predict the total number of infected cases, number of deaths, and duration of outbreaks among others. The model can be used to better understand the spread of Ebola, educate about prophylactic behaviors, and develop strategies that alter environment to achieve a disease-free state. A future work is to incorporate vaccination in the model when the vaccines are developed and the effects of vaccines are known better. PMID:26981342

  8. Quantum Spread Spectrum Communication

    SciTech Connect

    Humble, Travis S

    2010-01-01

    We demonstrate that spectral teleportation can coherently dilate the spectral probability amplitude of a single photon. In preserving the encoded quantum information, this variant of teleportation subsequently enables a form of quantum spread spectrum communication.

  9. 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,…

  10. Screwworms, Cochliomyia hominivorax, reared for mass release do not carry and spread foot-and-mouth disease virus and classical swine fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transporting live screwworms Cochliomyia hominivorax Coquerel for developing new strains from countries where foot-and-mouth disease (FMD) and classical swine fever (CSF) are endemic, to the mass rearing facilities in Mexico and Panama may introduce these exotic diseases. This study was conducted to...

  11. 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...

  12. Persistent spread of the rmtB 16S rRNA methyltransferase gene among Escherichia coli isolates from diseased food-producing animals in China.

    PubMed

    Xia, Jing; Sun, Jian; Cheng, Ke; Li, Liang; Fang, Liang-Xing; Zou, Meng-Ting; Liao, Xiao-Ping; Liu, Ya-Hong

    2016-05-30

    A total of 963 non-duplicate Escherichia coli strains isolated from food-producing animals between 2002 and 2012 were screened for the presence of the 16S rRNA methyltransferase genes. Among the positive isolates, resistance determinants to extended spectrum β-lactamases, plasmid-mediated quinolone resistance genes as well as floR and fosA/A3/C2 were detected using PCR analysis. These isolates were further subjected to antimicrobial susceptibility testing, molecular typing, PCR-based plasmid replicon typing and plasmid analysis. Of the 963 E. coli isolates, 173 (18.0%), 3 (0.3%) and 2 (0.2%) were rmtB-, armA- and rmtE-positive strains, respectively. All the 16S rRNA methyltransferase gene-positive isolates were multidrug resistant and over 90% of them carried one or more type of resistance gene. IncF (especially IncFII) and non-typeable plasmids played the main role in the dissemination of rmtB, followed by the IncN plasmids. Plasmids that harbored rmtB ranged in size from 20kb to 340kb EcoRI-RFLP testing of the 109 rmtB-positive plasmids from different years and different origins suggested that horizontal (among diverse animals) and vertical transfer of IncF, non-typeable and IncN-type plasmids were responsible for the spread of rmtB gene. In summary, our findings highlight that rmtB was the most prevalent 16S rRNA methyltransferase gene, which present persistent spread in food-producing animals in China and a diverse group of plasmids was responsible for rmtB dissemination.

  13. Food-and-Mouth Disease Vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease (FMD) is a highly contagious disease of domestic and wild cloven-hoofed animals. This disease has affected most areas of the world, often causing extensive epizootics in livestock, mostly farmed cattle and swine, although sheep, goats and many wild species are also susceptible...

  14. 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.

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

    PubMed Central

    Ayata, Cenk; Lauritzen, Martin

    2015-01-01

    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

  16. Feline parvovirus infection and associated diseases.

    PubMed

    Stuetzer, Bianca; Hartmann, Katrin

    2014-08-01

    Feline panleukopenia, caused by the single-stranded DNA virus feline parvovirus (FPV), is a highly contagious and often lethal disease of cats and other Felidae. FPV, but also canine parvovirus (CPV) can be isolated from both healthy and diseased cats. In Germany, CPV was detected in only approximately 10% of feline samples, but in Southeast Asia, reports estimated that up to approximately 80% of diseased cats were infected with CPV. Infection spreads rapidly, especially in cells with high mitotic activity, such as bone marrow, lymphoid tissue and intestinal crypt cells. Anorexia, vomiting, diarrhoea, neutropenia and lymphopenia are common in clinically affected cases. In utero or neonatal infection can result in cerebellar hypoplasia. Depending on the severity of clinical signs, mortality ranges from 25 to 100%. Effective vaccination and thorough disinfection are of the utmost importance in the prevention of disease transmission in multi-cat households and animal shelters. If clinical signs develop, supportive treatment should be commenced. The efficacy of feline recombinant interferon and FPV antibodies has not been clearly demonstrated. Commercially available vaccines should induce protective immunity when administered according to current guidelines. Recent studies suggest that in some kittens, maternally derived antibodies (MDA) can persist for much longer than has been previously recognised. FPV serum antibody tests are available, but protection status needs to be interpreted with caution in kittens with MDA and a negative titre in adult cats does not necessarily denote lack of protection.

  17. QS-21 enhances the early antibody response to oil adjuvant foot-and-mouth disease vaccine in cattle

    PubMed Central

    2016-01-01

    Purpose One of the most important tools against foot-and-mouth disease, a highly contagious and variable viral disease of cloven-hoofed animals, is vaccination. However, the effectiveness of foot-and-mouth disease vaccines on slowing the spread of the disease is questionable. In contrast, high potency vaccines providing early protection may solve issues with the spread of the disease, escaping mutants, and persistency. To increase the potency of the vaccine, additives such as saponin and aluminium hydroxide are used. However, the use of saponin with an oil adjuvant is not common and is sometimes linked to toxicity. QS-21, which is less toxic than Quil A, has been presented as an alternative for use with saponin. In this study, the addition of QS-21 to a commercially available foot-and-mouth disease water-in-oil-in-water emulsion vaccine was evaluated in cattle. Materials and Methods After vaccination, serum samples were collected periodically over 3 months. Sera of the QS-21 and normal oil vaccine groups were compared via serum virus neutralization antibody titre and liquid phase blocking enzyme-linked immunosorbent assay antibody titre. Results The results showed that there was a significant early antibody increase in the QS-21 group. Conclusion Strong early virus neutralizing antibody response will be useful for emergency or ring vaccinations against foot-and-mouth disease in target animals. PMID:27489804

  18. Review of the foot and mouth disease situation in North Africa and the risk of introducing the disease into Europe.

    PubMed

    Bouguedour, R; Ripani, A

    2016-12-01

    Foot and mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals, including cattle, pigs, sheep, goats, and certain wildlife species. The disease can cause massive economic losses when introduced into countries that were free from the infection, generating negative effects due to reduced animal productivity and restrictions on international livestock trade. Following 15 years of FMD absence, Tunisia and Algeria experienced an incursion of the disease in 2014. The epidemiological situation and disease control measures in operation for FMD in the North African region are not homogeneous. The FMD virus detected in Tunisia and Algeria during the epidemic in 2014 showed 99% identity with a strain isolated in Libya in 2013. Morocco was not affected by the 2014 epidemic but it started a preventive vaccination campaign for cattle in August of that year. The relatively short distance between the North African continent and southern Europe may facilitate the introduction of pathogens, including FMD virus. The history of infectious diseases demonstrates that the Mediterranean Sea is not a sufficient barrier to viral infections. Considering the geography and the FMD situation in North African countries, strong and coordinated intervention strategies are required, including economic, political and disease control aspects, to prevent the spread of FMD to other countries in North Africa or to other regions, e.g. southern Europe. Regional platforms such as the Mediterranean Animal Health Network (REMESA) could play a crucial role in coordinating and managing animal health crises, such as the 2014 FMD epidemic.

  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.

  20. Topology dependent epidemic spreading velocity in weighted networks

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  1. 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.

  2. Community Size Effects on Epidemic Spreading in Multiplex Social Networks

    PubMed Central

    Liu, Ting; Li, Ping; Chen, Yan; Zhang, Jie

    2016-01-01

    The dynamical process of epidemic spreading has drawn much attention of the complex network community. In the network paradigm, diseases spread from one person to another through the social ties amongst the population. There are a variety of factors that govern the processes of disease spreading on the networks. A common but not negligible factor is people’s reaction to the outbreak of epidemics. Such reaction can be related information dissemination or self-protection. In this work, we explore the interactions between disease spreading and population response in terms of information diffusion and individuals’ alertness. We model the system by mapping multiplex networks into two-layer networks and incorporating individuals’ risk awareness, on the assumption that their response to the disease spreading depends on the size of the community they belong to. By comparing the final incidence of diseases in multiplex networks, we find that there is considerable mitigation of diseases spreading for full phase of spreading speed when individuals’ protection responses are introduced. Interestingly, the degree of community overlap between the two layers is found to be critical factor that affects the final incidence. We also analyze the consequences of the epidemic incidence in communities with different sizes and the impacts of community overlap between two layers. Specifically, as the diseases information makes individuals alert and take measures to prevent the diseases, the effective protection is more striking in small community. These phenomena can be explained by the multiplexity of the networked system and the competition between two spreading processes. PMID:27007112

  3. 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.

  4. Spreading of miscible liquids

    NASA Astrophysics Data System (ADS)

    Walls, Daniel J.; Haward, Simon J.; Shen, Amy Q.; Fuller, Gerald G.

    2016-05-01

    Miscible liquids commonly contact one another in natural and technological situations, often in the proximity of a solid substrate. In the scenario where a drop of one liquid finds itself on a solid surface and immersed within a second, miscible liquid, it will spread spontaneously across the surface. We show experimental findings of the spreading of sessile drops in miscible environments that have distinctly different shape evolution and power-law dynamics from sessile drops that spread in immiscible environments, which have been reported previously. We develop a characteristic time to scale radial data of the spreading sessile drops based on a drainage flow due to gravity. This time scale is effective for a homologous subset of the liquids studied. However, it has limitations when applied to significantly chemically different, yet miscible, liquid pairings; we postulate that the surface energies between each liquid and the solid surface becomes important for this other subset of the liquids studied. Initial experiments performed with pendant drops in miscible environments support the drainage flow observed in the sessile drop systems.

  5. Prevalence of contagious mastitis pathogens in bulk tank milk in Québec

    PubMed Central

    Francoz, David; Bergeron, Luc; Nadeau, Marie; Beauchamp, Guy

    2012-01-01

    The objective of this study was to estimate the prevalence of mycoplasma, Staphylococcus aureus, and Streptococcus agalactiae in bulk tank milk (BTM) in Québec dairy herds. BTM was sampled 3 times a month in 117 randomly selected dairy herds. Samples were submitted for S. aureus, S. agalactiae, and mycoplasma and for direct mycoplasma detection by polymerase chain reaction (PCR). Mycoplasma spp. was identified at least once in 3 herds (2.6%) by primary culture and/or PCR and in 4 herds (3.4%) by enrichment culture and/or PCR. Staphylococcus aureus was isolated at least once in 99 (84.6%) and 112 (95.7%) herds in primary culture and after enrichment, respectively. Streptococcus agalactiae was isolated at least once in 9 (7.7%) and 10 (8.6%) herds in primary culture and after enrichment, respectively. Herd prevalence of mycoplasma was similar to that previously reported in Canada. Staphylococcus aureus is still by far the most important contagious mastitis pathogen. PMID:23543925

  6. Laboratory diagnosis of contagious ecthyma: comparison of different PCR protocols with virus isolation in cell culture.

    PubMed

    Kottaridi, Christine; Nomikou, Kiki; Lelli, Rossella; Markoulatos, Panayotis; Mangana, Olga

    2006-06-01

    A new polymerase chain reaction (PCR) assay for rapid diagnosis of contagious ecthyma was designed and applied to 21 clinical samples from Greece. This assay, which detects a highly conserved gene from the parapox genome, was evaluated for its sensitivity and specificity in order to be considered as a useful diagnostic tool. A comparative study with two published PCR protocols one using primers PPP1-PPP3, PPP1-PPP4 which targets putative virion envelope gene B2L and the other using VIR1-VIR2 primers which amplifies ORF virus interferon resistant (VIR) gene, as well as cell culture virus neutralization assay was carried out. All samples tested were amplified successfully with the PCR protocol established in the laboratory. The combination of primers PPP1-PPP3 and PPP1-PPP4 in a semi-nested PCR gave a positive result in 20 of 21 samples while primers VIR1-VIR2 failed to amplify successfully 7 of 21 samples. The diagnostic value of parapox viral DNA amplification was also compared with the results of virus isolation by cell culture and was positive in three samples that the virus isolation was obtained.

  7. Contagious yawning, social cognition, and arousal: an investigation of the processes underlying shelter dogs' responses to human yawns.

    PubMed

    Buttner, Alicia Phillips; Strasser, Rosemary

    2014-01-01

    Studies of contagious yawning have reported inconsistent findings regarding whether dogs exhibit this behavior and whether it is mediated by social-cognitive processes or the result of physiological arousal. We investigated why some dogs yawn in response to human yawns; particularly, whether these dogs are exceptional in their ability to understand human social cues or whether they were more physiologically aroused. Sixty shelter dogs were exposed to yawning and nonyawning control stimuli demonstrated by an unfamiliar human. We took salivary cortisol samples before and after testing to determine the role of arousal in yawn contagion. Dogs were tested on the object-choice task to assess their sensitivity for interpreting human social cues. We found that 12 dogs yawned only in response to human yawns (i.e., appeared to exhibit yawn contagion), though contagious yawning at the population level was not observed. Dogs that exhibited yawn contagion did not perform better on the object-choice task than other dogs, but their cortisol levels remained elevated after exposure to human yawning, whereas other dogs had reduced cortisol levels following yawning stimuli relative to their baseline levels. We interpret these findings as showing that human yawning, when presented in a stressful context, can further influence arousal in dogs, which then causes some to yawn. Although the precise social-cognitive mechanisms that underlie contagious yawning in dogs are still unclear, yawning between humans and dogs may involve some communicative function that is modulated by context and arousal.

  8. Contagious Comments: What Was the Online Buzz About the 2011 Quebec Measles Outbreak?

    PubMed Central

    Pereira, Jennifer A.; Quach, Susan; Dao, Huy Hao; Kwong, Jeffrey C.; Deeks, Shelley L.; Crowcroft, Natasha S.; Quan, Sherman D.; Guay, Maryse

    2013-01-01

    Background Although interruption of endemic measles was achieved in the Americas in 2002, Quebec experienced an outbreak in 2011 of 776 reported cases; 80% of these individuals had not been fully vaccinated. We analyzed readers’ online responses to Canadian news articles regarding the outbreak to better understand public perceptions of measles and vaccination. Methods We searched Canadian online English and French news sites for articles posted between April 2011 and March 2012 containing the words “measles” and “Quebec”. We included articles that i) concerned the outbreak or related vaccination strategies; and ii) generated at least ten comments. Two English and two bilingual researchers coded the unedited comments, categorizing codes to allow themes to emerge. Results We analyzed 448 comments from 188 individuals, in response to three French articles and six English articles; 112 individuals expressed positive perceptions of measles vaccination (2.2 comments/person), 38 were negative (4.2 comments/person), 11 had mixed feelings (1.5 comments/person), and 27 expressed no opinion (1.1 comments/person). Vaccine-supportive themes involved the success of vaccination in preventing disease spread, societal responsibility to vaccinate for herd immunity, and refutation of the autism link. Those against measles vaccination felt it was a personal rather than societal choice, and conveyed a distrust of vaccine manufacturers, believing that measles infection is not only safe but safer than vaccination. Commenters with mixed feelings expressed uncertainty of the infection’s severity, and varied in support of all vaccines based on perceived risk/benefit ratios. Conclusion The anti-vaccine minority’s volume of comments translates to a disproportionately high representation on online boards. Public health messages should address concerns by emphasizing that immunization is always a personal choice in Canada, and that the pharmaceutical industry is strictly

  9. 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

  10. The spread of non-OIE-listed avian diseases through international trade of chicken meat: an assessment of the risks to New Zealand.

    PubMed

    Cobb, S P; Smith, H

    2015-12-01

    Twelve avian diseases are listed by the World Organisation for Animal Health (OIE), although more than 100 infectious diseases have been described in commercial poultry. This article summarises a recent assessment of the biosecurity risks posed by non-listed avian diseases associated with imports of chilled or frozen chicken meat and meat products into New Zealand. Following the guidelines described in Chapter 2.1 of the OIE Terrestrial Animal Health Code, avian adenovirus splenomegaly virus, avian paramyxovirus-2 (APMV-2), Bordetella avium, Mycoplasma spp., Ureaplasma spp., Ornithobacterium rhinotracheale, Riemerella anatipestifer, and Salmonella arizonae have been identified as hazards. However, of all the non-listed avian diseases discussed here, only APMV-2 and S. arizonae are assessed as being risks associated with the commercial import of chicken meat into New Zealand. Specific control measures may have to be implemented to mitigate such risks. This conclusion is likely to reflect both the high-health status of New Zealand poultry and the threat posed by these infectious agents to New Zealand's unique population of native psittacine species.

  11. The Relationship Between Increasing Sea-surface Temperature and the Northward Spread of Perkinsus marinus(Dermo) Disease Epizootics in Oysters

    NASA Astrophysics Data System (ADS)

    Cook, T.; Folli, M.; Klinck, J.; Ford, S.; Miller, J.

    1998-04-01

    From its initial discovery in the Gulf of Mexico in the late 1940s until 1990,Perkinsus marinus, the parasite responsible for Dermo disease in the eastern oyster,Crassostrea virginica, was rarely found north of Chesapeake Bay. In 1990-92, an apparent range extension of the parasite led to epizootic outbreaks of the disease over a 500 km range north of Chesapeake Bay. One of the hypotheses for the range extension argues that small, undetected numbers of parasites were already present in northern oysters as the result of repeated historical introductions, and that a sharp warming trend in 1990-92 stimulated the disease outbreak. This argument was based on trends in air temperature. The present study examined this hypothesis by analysing water temperatures, rather than air temperatures, for five stations located in areas affected by the recent epizootics. At all five stations, there was a strong increasing trend in winter sea-surface temperature (SST) between 1986 and 1991. At four of the five stations, there was a smaller increasing trend in winter temperatures after 1960. There were no consistent or obvious trends in summer (August) temperatures. In Delaware Bay, which has a 40 year history of monitoring for oyster diseases, occasional findings ofP. marinusin oysters were correlated with warming episodes that were especially notable in the winter (February) record. Empirical orthogonal function (EOF) analysis showed that winter temperatures varied consistently at the stations examined and were associated with variations inP. marinusprevalence. Associations using EOF analysis with August temperatures were much weaker. The SST record is consistent with the hypothesis that increasing winter water temperatures have been important in the recent outbreak ofP. marinusepizootics in the north-eastern U.S.A.

  12. Spread spectrum image steganography.

    PubMed

    Marvel, L M; Boncelet, C R; Retter, C T

    1999-01-01

    In this paper, we present a new method of digital steganography, entitled spread spectrum image steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, error-control coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embedded control, and revision tracking.

  13. Reaction spreading on graphs.

    PubMed

    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 d{s}, the important quantity for reaction spreading is found to be the connectivity dimension d{l}. Numerical data, in agreement with analytical estimates based on the features of n independent random walkers on the graph, show that M(t)∼t{d{l}}. In the case of Erdös-Renyi random graphs, the reaction product is characterized by an exponential growth M(t)e{αt} with α proportional to ln(k), where (k) is the average degree of the graph.

  14. 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.

  15. 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.

  16. Contagious deposition of seeds in spider monkeys' sleeping trees limits effective seed dispersal in fragmented landscapes.

    PubMed

    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 (α-, β- and, γ-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. β-diversity of common and dominant species was two times greater among FF than between CFS. Although mean α-diversity per latrine did not differ among sites, the greater β-diversity among latrines in CFS increased γ-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 β-diversity among latrines) in fragmented landscapes.

  17. 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 (α-, β- and, γ-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. β-diversity of common and dominant species was two times greater among FF than between CFS. Although mean α-diversity per latrine did not differ among sites, the greater β-diversity among latrines in CFS increased γ-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 β-diversity among latrines) in fragmented landscapes. PMID:24586705

  18. 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...

  19. A network model for Ebola spreading.

    PubMed

    Rizzo, Alessandro; Pedalino, Biagio; Porfiri, Maurizio

    2016-04-07

    The availability of accurate models for the spreading of infectious diseases has opened a new era in management and containment of epidemics. Models are extensively used to plan for and execute vaccination campaigns, to evaluate the risk of international spreadings and the feasibility of travel bans, and to inform prophylaxis campaigns. Even when no specific therapeutical protocol is available, as for the Ebola Virus Disease (EVD), models of epidemic spreading can provide useful insight to steer interventions in the field and to forecast the trend of the epidemic. Here, we propose a novel mathematical model to describe EVD spreading based on activity driven networks (ADNs). Our approach overcomes the simplifying assumption of homogeneous mixing, which is central to most of the mathematically tractable models of EVD spreading. In our ADN-based model, each individual is not bound to contact every other, and its network of contacts varies in time as a function of an activity potential. Our model contemplates the possibility of non-ideal and time-varying intervention policies, which are critical to accurately describe EVD spreading in afflicted countries. The model is calibrated from field data of the 2014 April-to-December spreading in Liberia. We use the model as a predictive tool, to emulate the dynamics of EVD in Liberia and offer a one-year projection, until December 2015. Our predictions agree with the current vision expressed by professionals in the field, who consider EVD in Liberia at its final stage. The model is also used to perform a what-if analysis to assess the efficacy of timely intervention policies. In particular, we show that an earlier application of the same intervention policy would have greatly reduced the number of EVD cases, the duration of the outbreak, and the infrastructures needed for the implementation of the intervention.

  20. 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.

  1. Asymmetrically interacting spreading dynamics on complex layered networks

    PubMed Central

    Wang, Wei; Tang, Ming; Yang, Hui; Younghae Do; Lai, Ying-Cheng; Lee, GyuWon

    2014-01-01

    The spread of disease through a physical-contact network and the spread of information about the disease on a communication network are two intimately related dynamical processes. We investigate the asymmetrical interplay between the two types of spreading dynamics, each occurring on its own layer, by focusing on the two fundamental quantities underlying any spreading process: epidemic threshold and the final infection ratio. We find that an epidemic outbreak on the contact layer can induce an outbreak on the communication layer, and information spreading can effectively raise the epidemic threshold. When structural correlation exists between the two layers, the information threshold remains unchanged but the epidemic threshold can be enhanced, making the contact layer more resilient to epidemic outbreak. We develop a physical theory to understand the intricate interplay between the two types of spreading dynamics. PMID:24872257

  2. Development of a Novel Cocktail Enzyme-Linked Immunosorbent Assay and a Field-Applicable Lateral-Flow Rapid Test for Diagnosis of Contagious Bovine Pleuropneumonia

    PubMed Central

    Heller, Martin; Gicheru, Nimmo; Tjipura-Zaire, Georgina; Muriuki, Cecilia; Yu, Mingyan; Botelho, Ana; Naessens, Jan; Jores, Joerg

    2016-01-01

    Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease that is widespread in sub-Saharan Africa. It is caused by Mycoplasma mycoides subsp. mycoides, a bacterium belonging to the Mycoplasma mycoides cluster. In the absence of an efficient CBPP vaccine, improved and easy-to-use diagnostic assays for recurrent testing combined with isolation and treatment of positive animals represent an option for CBPP control in Africa. Here we describe the comprehensive screening of 17 immunogenic Mycoplasma mycoides subsp. mycoides proteins using well-characterized bovine sera for the development of a novel cocktail enzyme-linked immunosorbent assay (ELISA) for laboratory use. Two recombinant Mycoplasma immunogens, MSC_0136 and MSC_0636, were used to set up a standardized cocktail ELISA protocol. According to the results from more than 100 serum samples tested, the sensitivity and specificity of the novel cocktail ELISA were 85.6% and 96.4%, respectively, with an overall diagnostic accuracy comparable to that of the Office International des Epizooties (OIE)-prescribed serological assays. In addition, we provide a proof of principle for a field-applicable, easy-to-use commercially produced prototype lateral-flow test for rapid (<30-min) diagnosis of CBPP. PMID:27053669

  3. 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

  4. Social Big Data Analysis of Information Spread and Perceived Infection Risk During the 2015 Middle East Respiratory Syndrome Outbreak in South Korea.

    PubMed

    Song, Juyoung; Song, Tae Min; Seo, Dong-Chul; Jin, Dal-Lae; Kim, Jung Sun

    2017-01-01

    We investigated online diffusion of information, spread of fear, and perceived risk of infection to Middle East Respiratory Syndrome (MERS) as cases of MERS spread rapidly and dozens of fatalities occurred in South Korea in May-June of 2015. This study retrieved 8,671,695 MERS-related online documents from May 20 to June 18, 2015, from 171 Korean online channels and analyzed such documents by using multilevel models and data mining with Apriori algorithm association analysis. We used R software (version 3.2.1) for the association analysis data mining and visualization. Buzz with negative emotions (i.e., anxiety or fear) was more prevalent in online discussion boards, Twitter, and online cafes than news sites and blogs. News buzz (b = 0.21, p < 0.001), but not rumor buzz (b = 0.06, p = 0.308), was associated with positive MERS emotions (i.e., being calm or composed). The mention of eating immunity-boosting food in the news led to a 94 percent chance of a positive MERS emotion and that such a chance of showing a positive emotion was 4.75 times higher than that without such a mention (support of 0.001, confidence of 0.94, and lift of 4.75). Even with the same precautionary messages that were disseminated, they yielded the opposite emotional reactions to people depending on the channel through which the messages were communicated. In the face of a novel and highly contagious disease such as MERS, the government must deploy a response system that includes provision and dissemination of reliable information and inhibits online diffusion of false information.

  5. Chimpanzees show a developmental increase in susceptibility to contagious yawning: a test of the effect of ontogeny and emotional closeness on yawn contagion.

    PubMed

    Madsen, Elainie Alenkær; Persson, Tomas; Sayehli, Susan; Lenninger, Sara; Sonesson, Göran

    2013-01-01

    Contagious yawning has been reported for humans, dogs and several non-human primate species, and associated with empathy in humans and other primates. Still, the function, development and underlying mechanisms of contagious yawning remain unclear. Humans and dogs show a developmental increase in susceptibility to yawn contagion, with children showing an increase around the age of four, when also empathy-related behaviours and accurate identification of others' emotions begin to clearly evince. Explicit tests of yawn contagion in non-human apes have only involved adult individuals and examined the existence of conspecific yawn contagion. Here we report the first study of heterospecific contagious yawning in primates, and the ontogeny of susceptibility thereto in chimpanzees, Pan troglodytes verus. We examined whether emotional closeness, defined as attachment history with the yawning model, affected the strength of contagion, and compared the contagiousness of yawning to nose-wiping. Thirty-three orphaned chimpanzees observed an unfamiliar and familiar human (their surrogate human mother) yawn, gape and nose-wipe. Yawning, but not nose-wiping, was contagious for juvenile chimpanzees, while infants were immune to contagion. Like humans and dogs, chimpanzees are subject to a developmental trend in susceptibility to contagious yawning, and respond to heterospecific yawn stimuli. Emotional closeness with the model did not affect contagion. The familiarity-biased social modulatory effect on yawn contagion previously found among some adult primates, seem to only emerge later in development, or be limited to interactions with conspecifics. The influence of the 'chameleon effect', targeted vs. generalised empathy, perspective-taking and visual attention on contagious yawning is discussed.

  6. Chimpanzees Show a Developmental Increase in Susceptibility to Contagious Yawning: A Test of the Effect of Ontogeny and Emotional Closeness on Yawn Contagion

    PubMed Central

    Madsen, Elainie Alenkær; Persson, Tomas; Sayehli, Susan; Lenninger, Sara; Sonesson, Göran

    2013-01-01

    Contagious yawning has been reported for humans, dogs and several non-human primate species, and associated with empathy in humans and other primates. Still, the function, development and underlying mechanisms of contagious yawning remain unclear. Humans and dogs show a developmental increase in susceptibility to yawn contagion, with children showing an increase around the age of four, when also empathy-related behaviours and accurate identification of others’ emotions begin to clearly evince. Explicit tests of yawn contagion in non-human apes have only involved adult individuals and examined the existence of conspecific yawn contagion. Here we report the first study of heterospecific contagious yawning in primates, and the ontogeny of susceptibility thereto in chimpanzees, Pan troglodytes verus. We examined whether emotional closeness, defined as attachment history with the yawning model, affected the strength of contagion, and compared the contagiousness of yawning to nose-wiping. Thirty-three orphaned chimpanzees observed an unfamiliar and familiar human (their surrogate human mother) yawn, gape and nose-wipe. Yawning, but not nose-wiping, was contagious for juvenile chimpanzees, while infants were immune to contagion. Like humans and dogs, chimpanzees are subject to a developmental trend in susceptibility to contagious yawning, and respond to heterospecific yawn stimuli. Emotional closeness with the model did not affect contagion. The familiarity-biased social modulatory effect on yawn contagion previously found among some adult primates, seem to only emerge later in development, or be limited to interactions with conspecifics. The influence of the ‘chameleon effect’, targeted vs. generalised empathy, perspective-taking and visual attention on contagious yawning is discussed. PMID:24146848

  7. Outbreak of Neisseria meningitidis C in workers at a large food-processing plant in Brazil: challenges of controlling disease spread to the larger community.

    PubMed

    Iser, B P M; Lima, H C A V; de Moraes, C; de Almeida, R P A; Watanabe, L T; Alves, S L A; Lemos, A P S; Gorla, M C O; Gonçalves, M G; Dos Santos, D A; Sobel, J

    2012-05-01

    SUMMARYAn outbreak of meningococcal disease (MD) with severe morbidity and mortality was investigated in midwestern Brazil in order to identify control measures. A MD case was defined as isolation of Neisseria meningitidis, or detection of polysaccharide antigen in a sterile site, or presence of clinical purpura fulminans, or an epidemiological link with a laboratory-confirmed case-patient, between June and August 2008. In 8 out of 16 MD cases studied, serogroup C ST103 complex was identified. Five (31%) cases had neurological findings and five (31%) died. The attack rate was 12 cases/100 000 town residents and 60 cases/100 000 employees in a large local food-processing plant. We conducted a matched case-control study of eight primary laboratory-confirmed cases (1:4). Factors associated with illness in single variable analysis were work at the processing plant [matched odds ratio (mOR) 22, 95% confidence interval (CI) 2·3-207·7, P<0·01], and residing <1 year in Rio Verde (mOR 7, 95% CI 1·11-43·9, P<0·02). Mass vaccination (>10 000 plant employees) stopped propagation in the plant, but not in the larger community.

  8. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 1. Description of the problem, methods, and agents involved.

    PubMed

    Greig, Judy D; Todd, Ewen C D; Bartleson, Charles A; Michaels, Barry S

    2007-07-01

    Food workers in many settings have been responsible for foodborne disease outbreaks for decades, and there is no indication that this is diminishing. The Committee on Control of Foodborne Illnesses of the International Association for Food Protection was tasked with collecting and evaluating any data on worker-associated outbreaks. A total of 816 reports with 80,682 cases were collected from events that occurred from 1927 until the first quarter of 2006. Most of the outbreaks reviewed were from the United States, Canada, Europe, and Australia, with relatively few from other parts of the world, indicating the skewed set of data because of availability in the literature or personal contact. Outbreaks were caused by 14 agents: norovirus or probable norovirus (338), Salmonella enterica (151), hepatitis A virus (84), Staphylococcus aureus (53), Shigella spp. (33), Streptococcus Lancefield groups A and G (17), and parasites Cyclospora, Giardia, and Cryptosporidium (23). Streptococcal, staphylococcal, and typhoid outbreaks seem to be diminishing over time; hepatitis A virus remains static, whereas norovirus and maybe nontyphoidal Salmonella are increasing. Multiple foods and multi-ingredient foods were identified most frequently with outbreaks, perhaps because of more frequent hand contact during preparation and serving.

  9. CFD Simulation of Spread Risks of Infectious Disease due to Interactive Wind and Ventilation Airflows via Window Openings in High-Rise Buildings

    NASA Astrophysics Data System (ADS)

    Niu, J. L.; Gao, N. P.

    2010-05-01

    One of the concerns is that there may exist multiple infectious disease transmission routes across households in high-rise residential buildings, one of which is the natural ventilative airflow through open windows between flats, caused by buoyancy effects. This study presents the modeling of this cascade effect using computational fluid dynamics (CFD) technique. It is found that the presence of the pollutants generated in the lower floor is generally lower in the immediate upper floor by two orders of magnitude, but the risk of infection calculated by the Wells-Riley equation is only around one order of magnitude lower. It is found that, with single-side open-window conditions, wind blowing perpendicularly to the building may either reinforce or suppress the upward transport, depending on the wind speed. High-speed winds can restrain the convective transfer of heat and mass between flats, functioning like an air curtain. Despite the complexities of the air flow involved, it is clear that this transmission route should be taken into account in infection control.

  10. Hybrid spread spectrum radio system

    DOEpatents

    Smith, Stephen F [London, TN; Dress, William B [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. 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

  12. 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

    2014-08-08

    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.

  13. Western blot analysis of virus-specific antibody responses for capripox and contagious pustular dermatitis viral infections in sheep.

    PubMed

    Chand, P; Kitching, R P; Black, D N

    1994-10-01

    This paper reports the development and evaluation of serological tests for the differentiation of antibodies in animals infected with capripox and parapox viruses. Agar-gel immunodiffusion tests using sera from sheep with naturally-acquired infections and from sheep experimentally inoculated with orf or capripox viruses showed cross reactions. Virus-specific antibody responses to structural proteins of the viruses were analysed by Western-blot analysis. This analysis readily differentiated the infections as either capripox or contagious pustular dermatitis. The antibody responses to the 32 kDa and 26 kDa proteins of capripoxvirus provided a firm basis for differentiation.

  14. The Creation of a Contagious H5N1 Influenza Virus: Implications for the Education of Life Scientists

    PubMed Central

    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

  15. A Deadly Path: Bacterial Spread During Bubonic Plague.

    PubMed

    Gonzalez, Rodrigo J; Miller, Virginia L

    2016-04-01

    Yersinia pestis causes bubonic plague, a fulminant disease where host immune responses are abrogated. Recently developed in vivo models of plague have resulted in new ideas regarding bacterial spread in the body. Deciphering bacterial spread is key to understanding Y. pestis and the immune responses it encounters during infection.

  16. Is obesity contagious? Social networks vs. environmental factors in the obesity epidemic.

    PubMed

    Cohen-Cole, Ethan; Fletcher, Jason M

    2008-09-01

    This note's aim is to investigate the sensitivity of Christakis and Fowler's claim [Christakis, N., Fowler, J., 2007. The spread of obesity in a large social network over 32 years. The New England Journal of Medicine 357, 370-379] that obesity has spread through social networks. It is well known in the economics literature that failure to include contextual effects can lead to spurious inference on "social network effects." We replicate the NEJM results using their specification and a complementary dataset. We find that point estimates of the "social network effect" are reduced and become statistically indistinguishable from zero once standard econometric techniques are implemented. We further note the presence of estimation bias resulting from use of an incorrectly specified dynamic model.

  17. Epidemic spreading on evolving signed networks

    NASA Astrophysics Data System (ADS)

    Saeedian, M.; Azimi-Tafreshi, N.; Jafari, G. R.; Kertesz, J.

    2017-02-01

    Most studies of disease spreading consider the underlying social network as obtained without the contagion, though epidemic influences people's willingness to contact others: A "friendly" contact may be turned to "unfriendly" to avoid infection. We study the susceptible-infected disease-spreading model on signed networks, in which each edge is associated with a positive or negative sign representing the friendly or unfriendly relation between its end nodes. In a signed network, according to Heider's theory, edge signs evolve such that finally a state of structural balance is achieved, corresponding to no frustration in physics terms. However, the danger of infection affects the evolution of its edge signs. To describe the coupled problem of the sign evolution and disease spreading, we generalize the notion of structural balance by taking into account the state of the nodes. We introduce an energy function and carry out Monte Carlo simulations on complete networks to test the energy landscape, where we find local minima corresponding to the so-called jammed states. We study the effect of the ratio of initial friendly to unfriendly connections on the propagation of disease. The steady state can be balanced or a jammed state such that a coexistence occurs between susceptible and infected nodes in the system.

  18. An alternate delivery system improves vaccine performance against foot-and-mouth disease virus (FMDV).

    PubMed

    Pandya, Mital; Pacheco, Juan M; Bishop, Elizabeth; Kenney, Mary; Milward, Francis; Doel, Timothy; Golde, William T

    2012-04-26

    Foot-and-mouth disease virus (FMDV) causes vesicular disease of cloven-hoofed animals with severe agricultural and economic implications. One of the most highly infectious and contagious livestock pathogens known, the disease spreads rapidly in naïve populations making it critical to have rapidly acting vaccines. Needle inoculation of killed virus vaccine is an efficient method of swiftly vaccinating large numbers of animals, either in eradication efforts or in outbreak situations in disease free countries, although, to be efficient, this requires utilizing the same needle with multiple animals. Here we present studies using a needle free system for vaccination with killed virus vaccine, FMDV strain O1 Manisa, as a rapid and consistent delivery platform. Cattle were vaccinated using a commercially available vaccine formulation at the manufacturer's recommended dose as well as four and sixteen fold less antigen load per dose. Animals were challenged intradermalingually (IDL) with live, virulent virus, homologous strain O1 Manisa, at various times following vaccination. All non-vaccinated control cattle exhibited clinical disease, including fever, viremia and lesions, specifically vesicle formation. Cattle vaccinated with the 1/16× and 1/4× doses using the needle free device were protected when challenged at both 7 and 28 days after vaccination. These data suggest that effective protection against disease can be achieved with 1/16 of the recommended vaccine dose when delivered using the needle free, intradermal delivery system, indicating the current vaccine stockpile that can be extended by many fold using this system.

  19. Preventing the Spread of Illness in Child Care or School

    MedlinePlus

    ... Print Share Reducing the Spread of Illness in Child Care Page Content ​​Whenever children are together, there is ... each dose. Measures to Promote Good Hygiene in Child Care: To reduce the risk of disease in child ...

  20. Prion-like spread of protein aggregates in neurodegeneration.

    PubMed

    Polymenidou, Magdalini; Cleveland, Don W

    2012-05-07

    Protein misfolding is common to most neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. Recent work using animal models with intracellular α-synuclein and tau inclusions adds decisively to a growing body of evidence that misfolded protein aggregates can induce a self-perpetuating process that leads to amplification and spreading of pathological protein assemblies. When coupled with the progressive nature of neurodegeneration, recognition of such cell-to-cell aggregate spread suggests a unifying mechanism underlying the pathogenesis of these disorders.

  1. 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.

  2. The role of international transport of equine semen on disease transmission.

    PubMed

    Metcalf, E S

    2001-12-03

    Despite the numerous benefits of having the capability to transport semen internationally, there are serious potential ramifications if that semen is contaminated with a communicable disease. Bacteria: Many commensal bacteria colonize the exterior of the stallion penis and are not regarded as pathogenic. They may be cultured from an ejaculate. Alterations of the normal bacterial flora on the exterior genitalia may cause the growth of opportunistic bacteria such as Klebsiella pneumonia, Pseudomonas aeruginosa, Streptococcus zooepidemicus, which, if inseminated, may cause infertility in susceptible mares. Contagious equine metritis (CEM), a highly transmissible, true venereal disease of horses, is caused by the gram-negative coccobacillis, Taylorella equigenitalis. Even with the use of rigorous testing protocols, the current techniques used may not ensure accuracy of results. Viruses: Equine coital exanthema (equine herpes virus type 3; EHV-3) is a highly contagious virus that causes painful lesions on the stallion's penis and mare's vulva. Although it is primarily transmitted through coitus, infected fomites have also been implicated in its spread. Therefore, it is possible that the virus can potentially be transmitted to the ejaculate through penile contact with an artificial vagina or sleeve. Equine arteritis virus appears to be becoming more prevalent in recent years. The most common method of transmission is through respiratory disease, but the organism can also be shed in the semen of asymptomatic stallions. Equine infectious anemia virus has also been found to be present in the semen of an infected stallion, although no evidence exists at this time that there is venereal transmission of this disease. Protozoa: Dourine, caused by Trympanosoma equiperidum, is a venereal disease found only in Africa, South and Central America and the Middle East. Serological testing using complement fixation is recommended for diagnosis. Piroplasmosis, a disease caused by Babesia

  3. Differentially Expressed Genes in Bordetella pertussis Strains Belonging to a Lineage Which Recently Spread Globally

    PubMed Central

    de Gouw, Daan; Hermans, Peter W. M.; Bootsma, Hester J.; Zomer, Aldert; Heuvelman, Kees; Diavatopoulos, Dimitri A.; Mooi, Frits R.

    2014-01-01

    Pertussis is a highly contagious, acute respiratory disease in humans caused by the Gram-negative pathogen Bordetella pertussis. Pertussis has resurged in the face of intensive vaccination and this has coincided with the emergence of strains carrying a particular allele for the pertussis toxin promoter, ptxP3, which is associated with higher levels of pertussis toxin (Ptx) production. Within 10 to 20 years, ptxP3 strains have nearly completely replaced the previously dominant ptxP1 strains resulting in a worldwide selective sweep. In order to identify B. pertussis genes associated with the selective sweep, we compared the expression of genes in ptxP1 and ptxP3 strains that are under control of the Bordetella master virulence regulatory locus (bvgASR). The BvgAS proteins comprise a two component sensory transduction system which is regulated by temperature, nicotinic acid and sulfate. By increasing the sulfate concentration, it is possible to change the phase of B. pertussis from virulent to avirulent. Until recently, the only distinctive phenotype of ptxP3 strains was a higher Ptx production. Here we identify additional phenotypic differences between ptxP1 and ptxP3 strains which may have contributed to its global spread by comparing global transcriptional responses under sulfate-modulating conditions. We show that ptxP3 strains are less sensitive to sulfate-mediated gene suppression, resulting in an increased production of the vaccine antigens pertactin (Prn) and Ptx and a number of other virulence genes, including a type III secretion toxin, Vag8, a protein involved in complement resistance, and lpxE involved in lipid A modification. Furthermore, enhanced expression of the vaccine antigens Ptx and Prn by ptxP3 strains was confirmed at the protein level. Identification of genes differentially expressed between ptxP1 and ptxP3 strains may elucidate how B. pertussis has adapted to vaccination and allow the improvement of pertussis vaccines by identifying novel

  4. 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.

  5. 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…

  6. 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…

  7. A molecular epidemiology of treponemes in beef cattle digital dermatitis lesions and comparative analyses with sheep contagious ovine digital dermatitis and dairy cattle digital dermatitis lesions.

    PubMed

    Sullivan, L E; Evans, N J; Blowey, R W; Grove-White, D H; Clegg, S R; Duncan, J S; Carter, S D

    2015-07-09

    Bovine digital dermatitis (BDD) is an infective foot disease commonly reported in dairy cattle where Treponema are considered as the primary causative infectious agents. There still remains little definitive information on the etiology of BDD in beef cattle suggesting further investigations are warranted. Beef BDD lesions (n=34) and healthy beef foot tissues (n=38) were analysed by PCR for three BDD-associated Treponema phylogroups and also for Dichelobacter nodosus and Fusobacterium necrophorum. Spirochete culture was attempted on all BDD lesion samples. One or more BDD-associated Treponema phylogroups were detected in 100% of beef BDD lesions. "Treponema medium/Treponema vincentii-like", "Treponema phagedenis-like" and Treponema pedis spirochetes were identified in 27/34 (79%), 31/34 (91%) and 24/34 (71%) of BDD lesions, respectively. No BDD-associated treponeme DNA was amplified from beef healthy foot tissues. D. nodosus and F. necrophorum were present in 24/34 (71%) and 15/34 (44%) of lesions and 10/38 (26%) and 12/38 (32%) of healthy foot tissues, respectively. Twenty spirochetes were isolated from beef BDD lesions; 19 were representatives of the three BDD-associated Treponema phylogroups. One spirochete isolate shared less than 97% 16S rRNA gene similarity to the three cultivable BDD-associated Treponema phylogroups and therefore may represent a novel taxa of Treponema. Upon comparison, sheep contagious ovine digital dermatitis (CODD), dairy cattle and beef cattle BDD lesions appear to have extremely similar bacteriological data and therefore provides evidence of a shared etiopathogenesis posing concerns for cross-species transmission.

  8. Sinking, wedging, spreading - viscous spreading on a layer of fluid

    NASA Astrophysics Data System (ADS)

    Bergemann, Nico; Juel, Anne; Heil, Matthias

    2016-11-01

    We study the axisymmetric spreading of a sessile drop on a pre-existing layer of the same fluid in a regime where the drop is sufficiently large so that the spreading is driven by gravity while capillary and inertial effects are negligible. Experiments performed with 5 ml drops and layer thicknesses in the range 0.1 mm <= h <= 1 mm show that at long times the radius of the drop evolves as R tn , where the spreading exponent n increases with the layer thickness h. Numerical simulations, based on the axisymmetric free-surface Navier-Stokes equations, reveal three distinct spreading regimes depending on the layer thickness. For thick layers the drop sinks into the layer, accompanied by significant flow in the layer. By contrast, for thin layers the layer ahead of the propagating front is at rest and the spreading behaviour resembles that of a gravity-driven drop spreading on a dry substrate. In the intermediate regime the spreading is characterised by an advancing wedge, which is sustained by fluid flow from the drop into the layer.

  9. 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

  10. Western blot analysis of virus-specific antibody responses for capripox and contagious pustular dermatitis viral infections in sheep.

    PubMed Central

    Chand, P.; Kitching, R. P.; Black, D. N.

    1994-01-01

    This paper reports the development and evaluation of serological tests for the differentiation of antibodies in animals infected with capripox and parapox viruses. Agar-gel immunodiffusion tests using sera from sheep with naturally-acquired infections and from sheep experimentally inoculated with orf or capripox viruses showed cross reactions. Virus-specific antibody responses to structural proteins of the viruses were analysed by Western-blot analysis. This analysis readily differentiated the infections as either capripox or contagious pustular dermatitis. The antibody responses to the 32 kDa and 26 kDa proteins of capripoxvirus provided a firm basis for differentiation. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7925674

  11. Drop spreading with random viscosity

    PubMed Central

    2016-01-01

    We examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid’s viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. The solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. To examine how this variability influences the drop’s motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. We assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. The solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop’s effective contact lines has a long-lived influence on the spreading rate. Over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated viscosity within the precursor film to hinder spreading. A low-order model provides explicit predictions of the variances in spreading rate and drop location, which are validated against simulations. PMID:27843398

  12. Drop spreading with random viscosity

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Jensen, Oliver E.

    2016-10-01

    We examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid's viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. The solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. To examine how this variability influences the drop's motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. We assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. The solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop's effective contact lines has a long-lived influence on the spreading rate. Over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated viscosity within the precursor film to hinder spreading. A low-order model provides explicit predictions of the variances in spreading rate and drop location, which are validated against simulations.

  13. [20th century medical debate over venereal disease and prostitution].

    PubMed

    Lundberg, A

    2001-01-01

    In the early twentieth century a wider debate took place about how Swedish society was to fight the spread of contagious venereal diseases and in 1910 a government committee had written a law proposal that would dramatically reform these measures previously, Swedish physicians had been united against any measures against these diseases that did not involve the regulation of prostitutes, but this consensus was slowly withering away in the early parts of the century. Female doctors and a younger generation of venereologists was drawing the conclusion that mandatory checks of only one out of two sexes was insufficient. This article reviews the debate regarding the regulation of prostitution that took place between conservative and liberal members in the Swedish Medical Association in 1911. It depicts a fierce discussion between members that still clung to nineteenth-century ideas of women as being prone to prostitution if left idle and unemployed, and liberal members that believed social injustices such as low wages laid behind women's decisions. The study gives an insight into the complexities of building the Swedish welfare state.

  14. Spreading of Nematic Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Poulard, Christophe

    2004-11-01

    A cyanobiphenyl liquid crystal drop in the nematic phase should spread on a silicon wafer. In fact, the drop hardly spreads due to the strong antagonist anchoring on the substrate and at the free surface. In a humidity controlled box at high RH and on a hydrophilic substrate, the friction is considerably reduced and the drop spreads easily. A well defined instability develops at the contact line, with two characteristic wavelengths, associated with a modulation of the drop thickness. A theoretical analysis, made by M. Ben Amar and L. Cummings, allows to understand one of the wavelength by an elastic approach and gives a wavelength proportionnal to the local drop's thickness.

  15. 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 Central

    Durst, Ronen; Colombo, Roberto; Shpitzen, Shoshi; Avi, Liat Ben; Friedlander, Yechiel; Wexler, Roni; Raal, Frederick J.; Marais, David A.; Defesche, Joep C.; Mandelshtam, Michail Y.; Kotze, Maritha J.; Leitersdorf, Eran; Meiner, Vardiella

    2001-01-01

    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

  16. Contagious yawning in domestic dog puppies (Canis lupus familiaris): the effect of ontogeny and emotional closeness on low-level imitation in dogs.

    PubMed

    Madsen, Elainie Alenkær; Persson, Tomas

    2013-03-01

    Contagious yawning is a well-documented phenomenon in humans and has recently attracted much attention from developmental and comparative sciences. The function, development and underlying mechanisms of the phenomenon, however, remain largely unclear. Contagious yawning has been demonstrated in dogs and several non-human primate species, and theoretically and empirically associated with empathy in humans and non-human primates. Evidence of emotional closeness modulating contagious yawning in dogs has, nonetheless, been contradictory. Humans show a developmental increase in susceptibility to yawn contagion, with typically developing children displaying a substantial increase at the age of four, when a number of cognitive abilities (e.g. accurate identification of others' emotions) begin to clearly manifest. Explicit tests of yawn contagion in non-human animals have, however, thus far only involved adult individuals. Here, we report a study of the ontogeny of domestic dogs' (Canis lupus familiaris) susceptibility to yawn contagion, and whether emotional closeness to the yawning model affects this. Thirty-five dogs, aged 4-14 months, observed a familiar and unfamiliar human repeatedly yawn or gape. The dogs yawned contagiously, but emotional closeness with the model did not affect the strength of contagion, raising questions as to recent evidence of emotionally modulated auditory contagious yawning in dogs. The dogs showed a developmental effect, with only dogs above 7 months evidencing contagion. The results support the notion of a developmental increase in dogs' attention to others and identification of others' emotional states and suggest that yawn contagion is underpinned by developmental processes shared by humans and other animals.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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 ...

  2. Vaccines for prevention of bluetongue and epizootic hemorrhagic disease in livestock: A North American perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bluetongue (BT) and epizootic hemorrhagic disease (EHD) are non-contagious, insect transmitted diseases of domestic and wild ruminants caused by related but distinct viruses. Both BT (BTV) and EHD (EHDV) viruses cause hemorrhagic fevers in susceptible ruminants; however BT is principally a disease o...

  3. LincRNAs in CD4+ T cells and Marek’s disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is a T cell lymphoma of domestic chickens induced by Marek’s disease virus (MDV) and causes severe economic loss. The MDV is a naturally oncogenic, highly contagious, and cell associated alpha-herpesvirus. For a long time, resistance to MD and disease risk have long been thought...

  4. 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... PRODUCTS; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  5. 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... PRODUCTS; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  6. 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... PRODUCTS; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  7. 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... PRODUCTS; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  8. 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... PRODUCTS; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Ruminants § 93.416 Appearance of disease among ruminants in quarantine. If any contagious disease appears among ruminants during...

  9. Foot-and-mouth disease in Asiatic black bears (Ursus thibetanus).

    PubMed

    Officer, Kirsty; Lan, Nguyen Thi; Wicker, Leanne; Hoa, Nguyen Thi; Weegenaar, Annemarie; Robinson, Jill; Ryoji, Yamaguchi; Loukopoulos, Panayiotis

    2014-09-01

    Foot-and-mouth disease (FMD) is a highly contagious, debilitating, and globally significant viral disease typically affecting cloven-hoofed hosts. The diagnosis of FMD in bears in Vietnam is described. The current study describes a confirmed case of FMD in a bear species, and the clinical signs compatible with FMD in a Malayan sun bear. Thirteen Asiatic black bears (Ursus thibetanus) and 1 Malayan sun bear (Helarctos malayanus) were apparently affected. In August 2011, an adult bear became lethargic, and developed footpad vesicles. Over 15 days, 14 out of 17 bears developed similar signs; the remaining 3 co-housed bears and another 57 resident bears did not. All affected bears developed vesicles on all footpads, and most were lethargic for 24-48 hr. Nasal and oral lesions were noted in 6 and 3 cases, respectively. Within 1 month, all looked normal. Foot-and-mouth disease virus (FMDV) was detected by reverse transcription polymerase chain reaction, classified as serotype O, and isolated by virus isolation techniques. Phylogenetic analysis demonstrated clustering of 3 bear isolates, in a branch distinct from other FMDV type O isolates. The outbreak likely occurred due to indirect contact with livestock, and was facilitated by the high density of captive bears. It showed that Asiatic black bears are capable of contracting FMDV and developing clinical disease, and that the virus spreads easily between bears in close contact.

  10. Spreading dynamics of polymer nanodroplets

    NASA Astrophysics Data System (ADS)

    Heine, David R.; Grest, Gary S.; Webb, Edmund B.

    2003-12-01

    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.

  11. Scaled experiments of volcanic spreading

    NASA Astrophysics Data System (ADS)

    Merle, Olivier; Borgia, Andrea

    1996-06-01

    Experiments were conducted to study the spreading of volcanic constructs. Volcanoes are simulated by a sand cone, and the volcanic substratum is simulated by a sand layer (brittle substratum) overlying a silicone layer (ductile substratum). Similarity conditions between natural volcanoes and experimental prototypes led to the definition of dimensionless π numbers. Experiments determine π values which predict whether or not spreading takes place. Of particular importance are the ratio between the thickness of the brittle substratum and the height of the volcano (π2) and the brittle/ductile ratio of the substratum (π3). π2 indicates that the volcano must be large enough to "break" the substratum before spreading occurs, whereas π3 controls the style of deformation. During spreading, these dimensionless numbers change with time, reaching values that tend toward those observed for stable configurations. Experimental values are compared with those from well-constrained natural examples. It is found that an essential requirement for volcanic spreading is the presence of a low-viscosity layer within the substratum. Flow of the weak layer away from the excess load is responsible for the spreading. The overlying edifice displays radial intersecting grabens, due to concentric stretching, dissected summit areas; concentric zones of thrusts and folds form in the substratum around the edifice, and diapirs of the ductile substratum rise within the fault zones.

  12. 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.

  13. Spread dynamics of invasive species

    PubMed Central

    Arim, Matías; Abades, Sebastián R.; Neill, Paula E.; Lima, Mauricio; Marquet, Pablo A.

    2006-01-01

    Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and patterns of spread. However, there is no consensus regarding which species or community attributes enhance invader success or explain spread dynamics. Experimental and theoretical studies suggest that regulation of spread dynamics is possible; however, the conditions for its existence have not yet been empirically demonstrated. If invasion spread is a regulated process, the structure that accounts for this regulation will be a main determinant of invasion dynamics. Here we explore the existence of regulation underlying changes in the rate of new site colonization. We employ concepts and analytical tools from the study of abundance dynamics and show that spread dynamics are, in fact, regulated processes and that the regulation structure is notably consistent among invasions occurring in widely different contexts. We base our conclusions on the analysis of the spread dynamics of 30 species invasions, including birds, amphibians, fish, invertebrates, plants, and a virus, all of which exhibited similar regulation structures. In contrast to current beliefs that species invasions are idiosyncratic phenomena, here we provide evidence that general patterns do indeed exist. PMID:16387862

  14. Agent-based modeling to simulate the dengue spread

    NASA Astrophysics Data System (ADS)

    Deng, Chengbin; Tao, Haiyan; Ye, Zhiwei

    2008-10-01

    In this paper, we introduce a novel method ABM in simulating the unique process for the dengue spread. Dengue is an acute infectious disease with a long history of over 200 years. Unlike the diseases that can be transmitted directly from person to person, dengue spreads through a must vector of mosquitoes. There is still no any special effective medicine and vaccine for dengue up till now. The best way to prevent dengue spread is to take precautions beforehand. Thus, it is crucial to detect and study the dynamic process of dengue spread that closely relates to human-environment interactions where Agent-Based Modeling (ABM) effectively works. The model attempts to simulate the dengue spread in a more realistic way in the bottom-up way, and to overcome the limitation of ABM, namely overlooking the influence of geographic and environmental factors. Considering the influence of environment, Aedes aegypti ecology and other epidemiological characteristics of dengue spread, ABM can be regarded as a useful way to simulate the whole process so as to disclose the essence of the evolution of dengue spread.

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

    NASA Astrophysics Data System (ADS)

    Yao, Yiyang; Zhou, Yinzuo

    2017-02-01

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

  16. 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

  17. The contagious nature of imprisonment: an agent-based model to explain racial disparities in incarceration rates.

    PubMed

    Lum, Kristian; Swarup, Samarth; Eubank, Stephen; Hawdon, James

    2014-09-06

    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.

  18. 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 ...

  19. 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 ...

  20. 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 ...

  1. Worldwide spreading of economic crisis

    NASA Astrophysics Data System (ADS)

    Garas, Antonios; Argyrakis, Panos; Rozenblat, Céline; Tomassini, Marco; Havlin, Shlomo

    2010-11-01

    We model the spreading of a crisis by constructing a global economic network and applying the susceptible-infected-recovered (SIR) epidemic model with a variable probability of infection. The probability of infection depends on the strength of economic relations between a given pair of countries and the strength of the target country. It is expected that a crisis that originates in a large country, such as the USA, has the potential to spread globally, such as the recent crisis. Surprisingly, we also show that countries with a much lower GDP, such as Belgium, are able to initiate a global crisis. Using the k-shell decomposition method to quantify the spreading power (of a node), we obtain a measure of 'centrality' as a spreader of each country in the economic network. We thus rank the different countries according to the shell they belong to, and find the 12 most central ones. These countries are the most likely to spread a crisis globally. Of these 12, only six are large economies, while the other six are medium/small ones, a result that could not have been otherwise anticipated. Furthermore, we use our model to predict the crisis spreading potential of countries belonging to different shells according to the crisis magnitude.

  2. Colony spreading in Staphylococcus aureus.

    PubMed

    Kaito, Chikara; Sekimizu, Kazuhisa

    2007-03-01

    Wild-type Staphylococcus aureus rapidly expands on the surface of soft agar plates. The rates of expansion and the shapes of the resultant giant colonies were distinct for different strains of laboratory stocks and clinical isolates. The colony spreading abilities did not correlate with the biofilm-forming abilities in these strains. Insertional disruption of the dltABCD operon, which functions at the step of D-alanine addition to teichoic acids, and of the tagO gene, which is responsible for the synthesis of wall teichoic acids, decreased the colony spreading ability. The results indicate that wall teichoic acids and D-alanylation of teichoic acids are required for colony spreading.

  3. 9 CFR 319.762 - Ham spread, tongue spread, and similar products.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Ham spread, tongue spread, and similar products. 319.762 Section 319.762 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Salads and Meat Spreads § 319.762 Ham spread, tongue spread, and similar products. “Ham Spread,”...

  4. Braze alloy spreading on steel

    NASA Technical Reports Server (NTRS)

    Siewert, T. A.; Heine, R. W.; Lagally, M. G.

    1978-01-01

    Scanning electron microscopy (SEM) and Auger electron microscopy (AEM) were employed to observe elemental surface decomposition resulting from the brazing of a copper-treated steel. Two types of steel were used for the study, stainless steel (treated with a eutectic silver-copper alloy), and low-carbon steel (treated with pure copper). Attention is given to oxygen partial pressure during the processes; a low enough pressure (8 x 10 to the -5th torr) was found to totally inhibit the spreading of the filler material at a fixed heating cycle. With both types of steel, copper treatment enhanced even spreading at a decreased temperature.

  5. 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.

  6. 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...

  7. 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...

  8. Characterization of Newcastle disease viruses isolated from cormorant and gull species in the United States in 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newcastle disease virus (NDV), a member of the genus Avulavirus of the family Paramyxoviridae, is the causative agent of Newcastle disease (ND) a highly contagious disease that affects many species of birds and which frequently causes significant economic losses to the poultry industry worldwide. V...

  9. 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.

  10. Neuronal networks provide rapid neuroprotection against spreading toxicity

    PubMed Central

    Samson, Andrew J.; Robertson, Graham; Zagnoni, Michele; Connolly, Christopher N.

    2016-01-01

    Acute secondary neuronal cell death, as seen in neurodegenerative disease, cerebral ischemia (stroke) and traumatic brain injury (TBI), drives spreading neurotoxicity into surrounding, undamaged, brain areas. This spreading toxicity occurs via two mechanisms, synaptic toxicity through hyperactivity, and excitotoxicity following the accumulation of extracellular glutamate. To date, there are no fast-acting therapeutic tools capable of terminating secondary spreading toxicity within a time frame relevant to the emergency treatment of stroke or TBI patients. Here, using hippocampal neurons (DIV 15–20) cultured in microfluidic devices in order to deliver a localized excitotoxic insult, we replicate secondary spreading toxicity and demonstrate that this process is driven by GluN2B receptors. In addition to the modeling of spreading toxicity, this approach has uncovered a previously unknown, fast acting, GluN2A-dependent neuroprotective signaling mechanism. This mechanism utilizes the innate capacity of surrounding neuronal networks to provide protection against both forms of spreading neuronal toxicity, synaptic hyperactivity and direct glutamate excitotoxicity. Importantly, network neuroprotection against spreading toxicity can be effectively stimulated after an excitotoxic insult has been delivered, and may identify a new therapeutic window to limit brain damage. PMID:27650924

  11. Neuronal networks provide rapid neuroprotection against spreading toxicity.

    PubMed

    Samson, Andrew J; Robertson, Graham; Zagnoni, Michele; Connolly, Christopher N

    2016-09-21

    Acute secondary neuronal cell death, as seen in neurodegenerative disease, cerebral ischemia (stroke) and traumatic brain injury (TBI), drives spreading neurotoxicity into surrounding, undamaged, brain areas. This spreading toxicity occurs via two mechanisms, synaptic toxicity through hyperactivity, and excitotoxicity following the accumulation of extracellular glutamate. To date, there are no fast-acting therapeutic tools capable of terminating secondary spreading toxicity within a time frame relevant to the emergency treatment of stroke or TBI patients. Here, using hippocampal neurons (DIV 15-20) cultured in microfluidic devices in order to deliver a localized excitotoxic insult, we replicate secondary spreading toxicity and demonstrate that this process is driven by GluN2B receptors. In addition to the modeling of spreading toxicity, this approach has uncovered a previously unknown, fast acting, GluN2A-dependent neuroprotective signaling mechanism. This mechanism utilizes the innate capacity of surrounding neuronal networks to provide protection against both forms of spreading neuronal toxicity, synaptic hyperactivity and direct glutamate excitotoxicity. Importantly, network neuroprotection against spreading toxicity can be effectively stimulated after an excitotoxic insult has been delivered, and may identify a new therapeutic window to limit brain damage.

  12. Seroprevalence of contagious ecthyma in goats of Assam: An analysis by indirect enzyme-linked immunosorbent assay

    PubMed Central

    Bora, Mousumi; Bora, Durlav Prasad; Barman, Nagendra Nath; Borah, Biswajyoti; Das, Sutopa

    2016-01-01

    Aim: The objective of this study was to screen the prevalence of contagious ecthyma (CE) among the goat population of Assam owing to its high prevalence rate. Materials and Methods: In this study, a total of 231 serum samples were collected from 12 districts of Assam during September 2013 to July 2014. The serum samples were tested for the presence of antibodies against Orf virus (ORFV) by indirect enzyme-linked immunosorbent assay (ELISA). Indirect ELISA was standardized using purified Orf reference virus produced in bulk in primary lamb testes cells. Results: Studies on seroprevalence showed 76.62% of goats were seropositive. The total number of animals were divided into different age groups starting from 0-2 months, 2-4 months, 4-6 months, and above 8 months and accordingly highest prevalence of antibodies against ORFV was recorded in the age-group above 8 months of age. Significantly, lower rates of infection were observed in goats of age group 2-4 months. This study recorded that seropositivity from naturally infected animals and in contact apparently healthy animals to be 53.67% and 46.32%, respectively. Conclusion: The results indicated that CE is a prevalent infection in goats of Assam, and the healthy population is at increased risk of infection. PMID:27733808

  13. Effects on goat milk quality of the presence of Mycoplasma spp. in herds without symptoms of contagious agalactia.

    PubMed

    de la Fe, Christian; Sánchez, Antonio; Gutierrez, Aldo; Contreras, Antonio; Carlos Corrales, Juan; Assunçao, Patricia; Poveda, Carlos; Poveda, José B

    2009-02-01

    This study was designed to assess the possible effects of mycoplasmas on the quality of milk produced by goat herds in a contagious agalactia (CA) endemic area with absence of classical symptoms. Several factors related to milk quality (percentages of fat, total protein, lactose and total solids, standard plate counts (SPC) and presence of Staphylococcus aureus) were compared in mycoplasma-infected and non-infected herds. To define the CA status of 26 herds on the island of Lanzarote (Spain), where CA is endemic, 570 individual milk samples and 266 bulk tank milk (BTM) samples were microbiologically analysed for the presence of Mycoplasma spp. A herd was considered infected by mycoplasmas when at least a sample (individual or BTM) was positive. BTM samples were also used to determine milk quality parameters. Mycoplasma infection was confirmed in 13 herds. A total of 31, 10 and 11 strains of Mycoplasma mycoides subsp. mycoides LC (MmmLC), Mp. agalactiae and Mp. capricolum subsp. capricolum were isolated. No significant differences were observed between the least square means of the variables fat, total protein, lactose and total solids or SPC recorded for the infected v. non-infected herds. The Staph. aureus status of a herd was also found to be independent of the presence of Mycoplasma spp. Our findings indicate that neither the presence of mycoplasmas in a goat herd with absence of classical symptoms seem to compromise the quality of the BTM.

  14. Whole-flock, metaphylactic tilmicosin failed to eliminate contagious ovine digital dermatitis and footrot in sheep: a cluster randomised trial

    PubMed Central

    Angell, J. W.; Grove-White, D. H.; Williams, H. J.; Duncan, J. S.

    2016-01-01

    The aim of this study was to evaluate the clinical success of whole-flock systemic tilmicosin and enhanced biosecurity in eliminating active contagious ovine digital dermatitis (CODD) from sheep flocks. Thirty flocks in the UK were randomly allocated to receive either treatment as usual (as per the farmer's normal routine) or whole-flock treatment with tilmicosin, together with isolation and extended treatment of clinically affected individuals and isolation and treatment of purchased sheep during the study period. All flocks were visited once at onset of the trial to examine all sheep. One year later, all sheep were re-examined to determine the presence/absence of clinical lesions. The primary outcome was the clinical elimination of CODD from flocks. Secondary outcomes were reduction in prevalence of CODD, clinical elimination of footrot and reduction in prevalence of footrot. The analysis included 11 control flocks and 13 intervention flocks, with initially 3460 and 4686 sheep, respectively. For CODD: at follow-up, in the intervention group, 6/13 (46 per cent) flocks had a prevalence of zero compared with 1/11 (9 per cent) in the control group (P=0.12). For footrot: at follow-up, no flocks had a prevalence of zero. Therefore, the intervention is not recommended for the elimination of CODD or footrot in the UK. PMID:27450091

  15. Sheep and farm level factors associated with contagious ovine digital dermatitis: A longitudinal repeated cross-sectional study of sheep on six farms.

    PubMed

    Angell, J W; Grove-White, D H; Duncan, J S

    2015-11-01

    Contagious ovine digital dermatitis (CODD) is a cause of severe lameness in sheep in the UK currently affecting approximately 50% of farms. Six farms were studied in North Wales to investigate (1) the prevalence dynamics of CODD, (2) the association between sheep with CODD and potential risk factors and (3) the impact of CODD on lameness in sheep. The farms were visited at approximately two-month intervals between June 2012 and October 2013 and 6515 sheep were examined. The mean sheep level prevalence of CODD varied between farms (2.5-11.9%). Within farms, prevalence may increase in the late summer/early autumn and after housing. Environmental risk factors included larger flocks, lowland pasture, lush pasture and poached pasture. Co-infection of a foot with footrot was strongly associated with CODD in that foot (OR: 7.7 95% CI: 3.9-15.5 P<0.001) but negatively associated with co-infection of a foot with interdigital dermatitis (OR: 0.04 95% CI: 0.02-0.1 P<0.001). Reinfection with CODD was observed in 78 individual sheep but there was no re-infection at foot level. Lameness on all farms reduced during the study and seasonal changes in lameness followed similar patterns to those for CODD. Infection with CODD leads to a greater increase in locomotion score compared to footrot or interdigital dermatitis and CODD lesion grade was strongly associated with being lame. Sheep with CODD in more than one foot were more likely to be lame (OR: 25.0 95% CI: 12.5-49.9 P<0.001) than those with just one foot affected (OR:10.0 95% CI: 8.6-11.6 P<0.001). The biggest risk factor for CODD is co-infection with footrot and therefore control of footrot should help reduce the risk of CODD on affected farms. Furthermore environmental risk factors for CODD are similar to those for footrot adding weight for control strategies that target both diseases in tandem. The routine repeated gathering of sheep for the purposes of treating all lame sheep might be an effective control strategy for

  16. Epidemic spreading in time-varying community networks

    SciTech Connect

    Ren, Guangming E-mail: ren-guang-ming@163.com; 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 < q{sub c}. These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure.

  17. Dual polarized, heat spreading rectenna

    NASA Technical Reports Server (NTRS)

    Epp, Larry W. (Inventor); Khan, Abdur R. (Inventor); Smith, R. Peter (Inventor); Smith, Hugh K. (Inventor)

    1999-01-01

    An aperture coupled patch splits energy from two different polarization components to different locations to spread heat. In addition, there is no physical electrical connection between the slot, patch and circuitry. The circuitry is located under a ground plane which shields against harmonic radiation back to the RF source.

  18. 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.

  19. 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.

  20. 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.

  1. Control of contagious bovine pleuropneumonia: Knowledge, attitudes, perceptions and practices in Narok district of Kenya

    PubMed Central

    Kairu-Wanyoike, S.W.; Kiara, H.; Heffernan, C.; Kaitibie, S.; Gitau, G.K.; McKeever, D.; Taylor, N.M.

    2014-01-01

    CBPP is an important transboundary disease in sub-Saharan Africa whose control is urgent. Participatory data collection involving 52 focus group discussions in 37 village clusters and key informant interviews, a cross-sectional study involving 232 households and a post-vaccination follow up involving 203 households was carried out in 2006–2007 in Narok South district of Kenya. This was to investigate knowledge, attitudes, perceptions and practices (KAPP) associated with control of CBPP as well as the adverse post-vaccination reactions in animals in order to advice the control policy. The community perceived trans-boundary CBPP threat to their cattle. They had traditional disease coping mechanisms and were conversant with CBPP prevention and control with 49.8% (95%CI: 42.8–56.7%) giving priority to CBPP control. However, 12.9% (95%CI: 9.0–18.1%) of pastoralists had no knowledge of any prevention method and 10.0% (95%CI: 6.5–14.7%) would not know what to do or would do nothing in the event of an outbreak. Although 43.5% (95%CI: 37.1–50.2%) of pastoralists were treating CBPP cases with antimicrobials, 62.5% (95%CI: 52.1–71.7%) of them doubted the effectiveness of the treatments. Pastoralists perceived vaccination to be the solution to CBPP but vaccination was irregular due to unavailability of the vaccine. Vaccination was mainly to control outbreaks rather than preventive and exhibited adverse post-vaccination reactions among 70.4% (95%CI: 63.6–76.5%) of herds and 3.8% (95%CI: 3.5–4.2%) of animals. Consequently, nearly 25.2% (95%CI: 18.5–33.2%) of pastoralists may resist subsequent vaccinations against CBPP. Pastoralists preferred CBPP vaccination at certain times of the year and that it is combined with other vaccinations. In conclusion, pastoralists were not fully aware of the preventive measures and interventions and post-vaccination reactions may discourage subsequent CBPP vaccinations. Consequently there is need for monitoring and management of

  2. Control of contagious bovine pleuropneumonia: knowledge, attitudes, perceptions and practices in Narok district of Kenya.

    PubMed

    Kairu-Wanyoike, S W; Kiara, H; Heffernan, C; Kaitibie, S; Gitau, G K; McKeever, D; Taylor, N M

    2014-08-01

    CBPP is an important transboundary disease in sub-Saharan Africa whose control is urgent. Participatory data collection involving 52 focus group discussions in 37 village clusters and key informant interviews, a cross-sectional study involving 232 households and a post-vaccination follow up involving 203 households was carried out in 2006-2007 in Narok South district of Kenya. This was to investigate knowledge, attitudes, perceptions and practices (KAPP) associated with control of CBPP as well as the adverse post-vaccination reactions in animals in order to advice the control policy. The community perceived trans-boundary CBPP threat to their cattle. They had traditional disease coping mechanisms and were conversant with CBPP prevention and control with 49.8% (95%CI: 42.8-56.7%) giving priority to CBPP control. However, 12.9% (95%CI: 9.0-18.1%) of pastoralists had no knowledge of any prevention method and 10.0% (95%CI: 6.5-14.7%) would not know what to do or would do nothing in the event of an outbreak. Although 43.5% (95%CI: 37.1-50.2%) of pastoralists were treating CBPP cases with antimicrobials, 62.5% (95%CI: 52.1-71.7%) of them doubted the effectiveness of the treatments. Pastoralists perceived vaccination to be the solution to CBPP but vaccination was irregular due to unavailability of the vaccine. Vaccination was mainly to control outbreaks rather than preventive and exhibited adverse post-vaccination reactions among 70.4% (95%CI: 63.6-76.5%) of herds and 3.8% (95%CI: 3.5-4.2%) of animals. Consequently, nearly 25.2% (95%CI: 18.5-33.2%) of pastoralists may resist subsequent vaccinations against CBPP. Pastoralists preferred CBPP vaccination at certain times of the year and that it is combined with other vaccinations. In conclusion, pastoralists were not fully aware of the preventive measures and interventions and post-vaccination reactions may discourage subsequent CBPP vaccinations. Consequently there is need for monitoring and management of post vaccination

  3. Is participation contagious? Evidence from a household vector control campaign in urban Peru

    PubMed Central

    Buttenheim, Alison M.; Paz-Soldan, Valerie; Barbu, Corentin; Skovira, Christine; Calderón, Javier Quintanilla; Riveros, Lina Margot Mollesaca; Cornejo, Juan Oswaldo; Small, Dylan S.; Bicchieri, Christina; Naquira, Cesar; Levy, Michael Z.

    2013-01-01

    Objectives High rates of household participation are critical to the success of door-to-door vector control campaigns. We used the Health Belief Model to assess determinants of participation, including neighbor participation as a cue to action, in a Chagas disease vector control campaign in Peru. Methods We evaluated clustering of participation among neighbors; estimated participation as a function of household infestation status, neighborhood type, and number of participating neighbors; and described reported reasons for refusal to participate in a district of 2911 households. Results We observed significant clustering of participation along city blocks (p< .0001). Participation was significantly higher for households in new vs. established neighborhoods, for infested households, and for households with more participating neighbors. The effect of neighbor participation was greater in new neighborhoods. Conclusions Results support a “contagion” model of participation, highlighting the possibility that one or two participating households can tip a block towards full participation. Future campaigns can leverage these findings by making participation more visible, by addressing stigma associated with spraying, and by employing group incentives to spray. PMID:24062411

  4. Efficacy of two vaccine formulations against contagious bovine pleuropneumonia (CBPP) in Kenyan indigenous cattle

    PubMed Central

    Nkando, Isabel; Ndinda, Joycelyne; Kuria, Joseph; Naessens, Jan; Mbithi, Flora; Schnier, Christian; Gicheru, Michael; McKeever, Declan; Wesonga, Hezron

    2012-01-01

    A live, attenuated vaccine is currently the only viable option to control of CBPP in Africa. It has been suggested that simple modifications to current vaccines and protocols might improve efficacy in the field. In this report we compared the current vaccine formulation with a buffered preparation that maintains Mycoplasma viability at ambient temperature for a longer time. Groups of animals were vaccinated with the two formulations and compared with non vaccinated groups. Half of the animals in each group were challenged 3 months post vaccination, the other half after 16 months. Protection levels were measured using the pathology index, calculated from post mortem scores of lesions from animals killed during the course of clinical disease. In the challenge at 3 months post vaccination, the protection levels were 52% and 77% for the modified and current vaccine preparations, respectively. At 16 months post vaccination, the protection levels were 56% and 62% for the modified and current vaccine preparations, respectively. These findings indicate that there are no differences in protection levels between the two vaccines. Because of its longer half life after reconstitution, the modified vaccine might be preferred in field situations where the reconstituted vaccine is likely not to be administered immediately. PMID:21963291

  5. "Contagious Love": A Qualitative Study of the Couple Relationships of Ten AIDS Carriers

    PubMed Central

    Doron, Hadas; Teichner, Noa; Grey, Adi; Goldstein, Yehudit

    2008-01-01

    The qualitative study in this article portrays the couple relationship among AIDS carriers, based on Sternberg's triangular love theory (involving domains of intimacy, passion and commitment). The central study hypothesis is that certain components of the Sternberg model will be more significant than others among the AIDS carrier population. The study was conducted on ten AIDS carriers aged 21-37 who had experienced a couple relationship. Six men and four women participated; most of them were in a romantic couple relationship of homosexual orientation. The interviewees answered a questionnaire that included the three domains-- intimacy, passion and commitment--in the personal interview technique. The interview focused on interviewee's attitude towards his/her relationship with a partner, as he/she understood it. The findings of the study focus on relevant content that was gathered from the interviews and these portray a limited view of couple patterns in the world of AIDS carriers. The study reveals two major findings regarding the carrier's desires: On the one hand, the carrier describes a powerful need for a stable, permanent relationship--from the diagnosis of AIDS and throughout the subsequent years. On the other hand, the carrier also expresses powerful sexual desires that are not necessarily limited to a permanent partner. Thus passion is the dominant among the three domains. The intimacy domain is mainly affected by disclosure of the disease and the joint coping that follows. The findings are discussed in the context of the romantic internalized model theory and Sternberg's triangular love theory. PMID:18923698

  6. Cannibalism amplifies the spread of vertically transmitted pathogens.

    PubMed

    Sadeh, Asaf; Rosenheim, Jay A

    2016-08-01

    Cannibalism is a widespread behavior. Abundant empirical evidence demonstrates that cannibals incur a risk of contracting pathogenic infections when they consume infected conspecifics. However, current theory suggests that cannibalism generally impedes disease spread, because each victim is usually consumed by a single cannibal, such that cannibalism does not function as a spreading process. Consequently, cannibalism cannot be the only mode of transmission of most parasites. We develop simple, but general epidemiological models to analyze the interaction of cannibalism and vertical transmission. We show that cannibalism increases the prevalence of vertically transmitted pathogens whenever the host population density is not solely regulated by cannibalism. This mechanism, combined with additional, recently published, theoretical mechanisms, presents a strong case for the role of cannibalism in the spread of infectious diseases across a wide range of parasite-host systems.

  7. Smallpox: emergence, global spread, and eradication.

    PubMed

    Fenner, F

    1993-01-01

    Speculatively, it is suggested that variola virus, the cause of smallpox, evolved from an orthopoxvirus of animals of the central African rain forests (possibly now represented by Tatera poxvirus), some thousands of years ago, and first became established as a virus specific for human beings in the dense populations of the Nile valley perhaps five thousand years ago. By the end of the first millennium of the Christian era, it had spread to all the densely populated parts of the Eurasian continent and along the Mediterranean fringe of north Africa. It became established in Europe during the times of the Crusades. The great voyages of European colonization carried smallpox to the Americas and to Africa south of the Sahara. Transported across the Atlantic by Europeans and their African slaves, it played a major role in the conquest of Mexico and Peru and the European settlement of north America. Variolation, an effective preventive inoculation, was devised as early as the tenth century. In 1798 this practice was supplanted by Jenner's cowpox vaccine. In 1967, when the disease was still endemic in 31 countries and caused ten to fifteen million cases and about two million deaths annually, the World Health Organization embarked on a programme that was to see the disease eradicated globally just over ten years later, and the world was formally declared to be free of smallpox in May 1980. Smallpox is unique--a specifically human disease that emerged from some animal reservoir, spread to become a worldwide, severe and almost universal affliction, and finally underwent the reverse process to emergence, namely global eradication.

  8. Spreading of a granular droplet

    NASA Astrophysics Data System (ADS)

    Clement, Eric; Sanchez, Ivan; Raynaud, Franck; Lanuza, Jose; Andreotti, Bruno; Aranson, Igor

    2008-03-01

    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.

  9. Spreading of a granular droplet

    NASA Astrophysics Data System (ADS)

    Sánchez, Iván; Raynaud, Franck; Lanuza, José; Andreotti, Bruno; Clément, Eric; Aranson, Igor S.

    2007-12-01

    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.

  10. Lesion of the olfactory epithelium accelerates prion neuroinvasion and disease onset when prion replication is restricted to neurons.

    PubMed

    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.

  11. 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

  12. Spread of entanglement and causality

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Liu, Hong; Mezei, Márk

    2016-07-01

    We investigate causality constraints on the time evolution of entanglement entropy after a global quench in relativistic theories. We first provide a general proof that the so-called tsunami velocity is bounded by the speed of light. We then generalize the free particle streaming model of [1] to general dimensions and to an arbitrary entanglement pattern of the initial state. In more than two spacetime dimensions the spread of entanglement in these models is highly sensitive to the initial entanglement pattern, but we are able to prove an upper bound on the normalized rate of growth of entanglement entropy, and hence the tsunami velocity. The bound is smaller than what one gets for quenches in holographic theories, which highlights the importance of interactions in the spread of entanglement in many-body systems. We propose an interacting model which we believe provides an upper bound on the spread of entanglement for interacting relativistic theories. In two spacetime dimensions with multiple intervals, this model and its variations are able to reproduce intricate results exhibited by holographic theories for a significant part of the parameter space. For higher dimensions, the model bounds the tsunami velocity at the speed of light. Finally, we construct a geometric model for entanglement propagation based on a tensor network construction for global quenches.

  13. Drop Spreading with Random Viscosity

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Jensen, Oliver

    2016-11-01

    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  14. Spreading of persistent infections in heterogeneous populations

    NASA Astrophysics Data System (ADS)

    Sanz, J.; Floría, L. M.; Moreno, Y.

    2010-05-01

    Up to now, the effects of having heterogeneous networks of contacts have been studied mostly for diseases which are not persistent in time, i.e., for diseases where the infectious period can be considered very small compared to the lifetime of an individual. Moreover, all these previous results have been obtained for closed populations, where the number of individuals does not change during the whole duration of the epidemics. Here, we go one step further and analyze, both analytically and numerically, a radically different kind of diseases: those that are persistent and can last for an individual’s lifetime. To be more specific, we particularize to the case of tuberculosis’ (TB) infection dynamics, where the infection remains latent for a period of time before showing up and spreading to other individuals. We introduce an epidemiological model for TB-like persistent infections taking into account the heterogeneity inherent to the population structure. This sort of dynamics introduces new analytical and numerical challenges that we are able to sort out. Our results show that also for persistent diseases the epidemic threshold depends on the ratio of the first two moments of the degree distribution so that it goes to zero in a class of scale-free networks when the system approaches the thermodynamic limit.

  15. 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...

  16. 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 ...

  17. Modelling the spread of Wolbachia in spatially heterogeneous environments.

    PubMed

    Hancock, Penelope A; Godfray, H Charles J

    2012-11-07

    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.

  18. 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...

  19. Modelling dengue epidemic spreading with human mobility

    NASA Astrophysics Data System (ADS)

    Barmak, D. H.; Dorso, C. O.; Otero, M.

    2016-04-01

    We explored the effect of human mobility on the spatio-temporal dynamics of Dengue with a stochastic model that takes into account the epidemiological dynamics of the infected mosquitoes and humans, with different mobility patterns of the human population. We observed that human mobility strongly affects the spread of infection by increasing the final size and by changing the morphology of the epidemic outbreaks. When the spreading of the disease is driven only by mosquito dispersal (flight), a main central focus expands diffusively. On the contrary, when human mobility is taken into account, multiple foci appear throughout the evolution of the outbreaks. These secondary foci generated throughout the outbreaks could be of little importance according to their mass or size compared with the largest main focus. However, the coalescence of these foci with the main one generates an effect, through which the latter develops a size greater than the one obtained in the case driven only by mosquito dispersal. This increase in growth rate due to human mobility and the coalescence of the foci are particularly relevant in temperate cities such as the city of Buenos Aires, since they give more possibilities to the outbreak to grow before the arrival of the low-temperature season. The findings of this work indicate that human mobility could be the main driving force in the dynamics of vector epidemics.

  20. Intramolecular epitope spreading in Heymann nephritis.

    PubMed

    Shah, Pallavi; Tramontano, Alfonso; Makker, Sudesh P

    2007-12-01

    Immunization with megalin induces active Heymann nephritis, which reproduces features of human idiopathic membranous glomerulonephritis. Megalin is a complex immunological target with four discrete ligand-binding domains (LBDs) that may contain epitopes to which pathogenic autoantibodies are directed. Recently, a 236-residue N-terminal fragment, termed "L6," that spans the first LBD was shown to induce autoantibodies and severe disease. We used this model to examine epitope-specific contributions to pathogenesis. Sera obtained from rats 4 weeks after immunization with L6 demonstrated reactivity only with the L6 fragment on Western blot, whereas sera obtained after 8 weeks demonstrated reactivity with all four recombinant fragments of interest (L6 and LBDs II, III, and IV). We demonstrated that the L6 immunogen does not contain the epitopes responsible for the reactivity to the LBD fragments. Therefore, the appearance of antibodies directed at LBD fragments several weeks after the primary immune response suggests intramolecular epitope spreading. In vivo, we observed a temporal association between increased proteinuria and the appearance of antibodies to LBD fragments. These data implicate B cell epitope spreading in antibody-mediated pathogenesis of active Heymann nephritis, a model that should prove valuable for further study of autoimmune dysregulation.

  1. Reverse preferential spread in complex networks

    NASA Astrophysics Data System (ADS)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  2. Structuring the passive surveillance network improves epizootic detection and control efficacy: a simulation study on foot-and-mouth disease in France.

    PubMed

    Rautureau, S; Dufour, B; Durand, B

    2012-08-01

    Rapid detection of infection is critical to the containment and control of contagious pathogens. Passive surveillance, based on the detection of clinical signs through farmers' observations and subsequent veterinarian notification, is the primary means of initially detecting an epizootic and for implementing control measures. The objective of this study was to analyse how the composition and structure of passive surveillance networks may impact epizootic spread and control. Three compositions of passive surveillance network were considered: (i) A veterinarian-based surveillance network composed of farmers and veterinarians (the common passive surveillance network where each veterinarian follows up a group of holdings), (ii) a farmer-based surveillance network composed of farmers only (the farmer plays the same role as in the preceding network as well as that of the veterinarian but his point of view is limited to his animals) and (iii) a hierarchical surveillance network composed of farmers, veterinarians and district-level veterinarian specialists (in case of doubt, the local veterinarian calls the specialist veterinarian). We compared the efficacy of these different network types where actors have successively a structurally wider perspective than the preceding ones using a specific stochastic model for the spread of foot-and-mouth disease (FMD). The model was forced by actual data to generate realistic simulated FMD epizootics in France. Our results show that maintaining the presence of field veterinarians following-up several holdings in breeding areas is fundamental and adding veterinarian specialists to passive surveillance networks could greatly enhance surveillance network efficacy.

  3. Emergence and Spreading Potential of Zika Virus

    PubMed Central

    Fajardo, Álvaro; Cristina, Juan; Moreno, Pilar

    2016-01-01

    Zika virus (ZIKV) is an arthropod-borne Flavivirus (family Flaviviridae) closely related to dengue, yellow fever and West Nile viruses. ZIKV remained neglected, confined to enzootic transmission cycles in Africa and Asia, until the first significant outbreak was reported in Micronesia in 2007. Subsequent epidemics of growing incidence occurred in French Polynesia and other South Pacific Islands, and recently, in the Americas. The latter and currently ongoing outbreak of unprecedented incidence revealed the association of ZIKV infection with the occurrence of severe congenital malformations and neurological diseases, leading to a widespread concern about its potential to pose a global public health threat. Serological and molecular data suggest that the genetic and geographic diversification of ZIKV may be greatly underestimated. Here we discuss several ecological and epidemiological aspects, together with the evolutionary processes that may have driven the emergence and abrupt spread of ZIKV in the Americas. PMID:27812357

  4. 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.

  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

    ... 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Control of foot-and-mouth disease by using replication-defective human adenoviruses to deliver vaccines and biotherapeutics

    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...

  11. 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 ...

  12. Marek's disease virus immunosuppression alters host cellular responses and immune gene expression in the skin of infected chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is a highly contagious lymphoproliferative and neuropathic disease of chickens. The feather follicle epithelium (FFE) is the only anatomical site within the host where infectious enveloped cell-free MD virus (MDV) particles are produced and disseminated into the environment. MD ...

  13. 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...

  14. Geodynamic environments of ultra-slow spreading

    NASA Astrophysics Data System (ADS)

    Kokhan, Andrey; Dubinin, Evgeny

    2015-04-01

    Ultra-slow spreading is clearly distinguished as an outstanding type of crustal accretion by recent studies. Spreading ridges with ultra-slow velocities of extension are studied rather well. But ultra-slow spreading is characteristic feature of not only spreading ridges, it can be observed also on convergent and transform plate boundaries. Ultra-slow spreading is observed now or could have been observed in the past in the following geodynamic environments on divergent plate boundaries: 1. On spreading ridges with ultra-slow spreading, both modern (f.e. Gakkel, South-West Indian, Aden spreading center) and ceased (Labrador spreading center, Aegir ridge); 2. During transition from continental rifting to early stages of oceanic spreading (all spreading ridges during incipient stages of their formation); 3. During incipient stages of formation of spreading ridges on oceanic crust as a result of ridge jumps and reorganization of plate boundaries (f.e. Mathematicians rise and East Pacific rise); 4. During propagation of spreading ridge into the continental crust under influence of hotspot (Aden spreading center and Afar triple junction), under presence of strike-slip faults preceding propagation (possibly, rift zone of California Bay). Ultra-slow spreading is observed now or could have been observed in the past in the following geodynamic environments on transform plate boundaries: 1. In transit zones between two "typical" spreading ridges (f.e. Knipovich ridge); 2. In semi strike-slip/extension zones on the oceanic crust (f.e. American-Antarctic ridge); 3. In the zones of local extension in regional strike-slip areas in pull-apart basins along transform boundaries (Cayman trough, pull-apart basins of the southern border of Scotia plate). Ultra-slow spreading is observed now or could have been observed in the past in the following geodynamic environments on convergent plate boundaries: 1. During back-arc rifting on the stage of transition into back-arc spreading (central

  15. Qualitative and quantitative impacts assessment of contagious bovine pleuropneumonia in Fulani pastoral herds of North-central Nigeria: The associated socio-cultural factors.

    PubMed

    Alhaji, N B; Babalobi, O O

    2016-06-01

    Contagious bovine pleuropneumonia is one of the most important trans-boundary disease affecting Fulani cattle herds of Nigeria and whose control is urgently needed. A Participatory Epidemiology approach and cross-sectional study were concurrently conducted to investigate qualitative and quantitative impacts of CBPP, respectively and associated socio-cultural factors that influenced exposure of Fulani nomadic pastoral communities to its risk in Niger State, North-central Nigeria between January and December 2013. A total of nine pastoral communities were purposively selected for qualitative impact assessment using Participatory Rural Appraisal tools, while 765 cattle randomly sampled from 125 purposively selected nomadic herds were analyzed using c-ELISA. Data on socio-cultural characteristics were collected using structured questionnaires administered on nomadic herd owners of the 125 selected herds. Kendall's Coefficient of Concordance W statistics and OpenEpi 2.3 were used for statistical analyses. Pastoralists' dependent factors associated with their socio-cultural activities were tested using Chisquare tests and likelihood backward logistic regressions. The mean proportional piles (relative qualitative impact) of CBPP was 12.6%, and nomads agreement on this impact was strong (W=0.6855) and statistically significant (P<0.001). This was validated by 16.2% (95% CI: 13.7, 19.0) sero-positive (quantitative impact). Highest sero-prevalence of 25.3% was observed in Northern agro-ecological zone, while lowest of 6.2% was in Eastern zone. Pastoralists in the age groups 51-60 and 61-70 years were more likely (OR 13.07; 95% CI: 3.21, 53.12 and OR 7.10; 95% CI: 1.77, 28.33, respectively) to have satisfactory information/awareness on CBPP and lowland transhumance pastoralists were more likely (OR 5.21; 95% CI: 2.01, 13.54) to have satisfactory information. Socio-cultural activities of extensive husbandry system was six times more likely (OR 5.79; 95% CI: 2.55, 13.13) to be

  16. 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

  17. Hybrid spread spectrum radio system

    DOEpatents

    Smith, Stephen F.; Dress, William B.

    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.

  18. 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

  19. Lexical Ambiguity: Making a Case against Spread

    ERIC Educational Resources Information Center

    Kaplan, Jennifer J.; Rogness, Neal T.; Fisher, Diane G.

    2012-01-01

    We argue for decreasing the use of the word "spread" when describing the statistical idea of dispersion or variability in introductory statistics courses. In addition, we argue for increasing the use of the word "variability" as a replacement for "spread."

  20. 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)