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1

The effect of travel restrictions on the spread of a highly contagious disease in Sweden  

Microsoft Academic Search

Travel restrictions may reduce the spread of a contagious disease that threatens public health. In this study we investigate what effect different levels of travel restrictions may have on the speed and geographical spread of an outbreak of a disease similar to SARS. We use a stochastic simulation model of the Swedish population, calibrated with survey data of travel patterns

Martin Camitz; Fredrik Liljeros

2005-01-01

2

Early detection of contagious diseases  

DOEpatents

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.

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

2011-08-09

3

Who should wear mask against airborne infections? Altering the contact network for controlling the spread of contagious diseases  

Microsoft Academic Search

There are several ways of controlling the propagation of a contagious disease. For instance, to reduce the spreading of an airborne infection, individuals can be encouraged to remain in their homes and\\/or to wear face masks outside their domiciles. However, when a limited amount of masks is available, who should use them: the susceptible subjects, the infective persons or both

P. H. T. Schimit; L. H. A. Monteiro

2010-01-01

4

Childhood Contagious Diseases  

MedlinePLUS

newsletter | contact Share | Childhood Contagious Diseases A A A Children have maturing immune systems and are often in close proximity to one another, ... in tinea infections, commonly called "ringworm"). Fortunately, many childhood diseases, once contracted, result in lifelong immunity in ...

5

Basic Methods for Modeling the Invasion and Spread of Contagious Diseases  

Microsoft Academic Search

The evolution of disease requires a flrm understanding of hetero- geneity among pathogen strains and hosts with regard to the processes of transmission, movement, recovery, and pathobiology. In this and a companion chapter (Getz et al. this volume), we focus on the question of how to model the invasion and spread of diseases in heterogeneous environments, without making an explicit

Wayne M. Getz; James O. Lloyd-Smith

2005-01-01

6

Modeling the Invasion and Spread of Contagious Diseases in Heterogeneous Populations  

Microsoft Academic Search

The evolution of disease requires a rm understanding of hetero- geneity among pathogen strains and hosts with regard to the processes of transmission, movement, recovery, and pathobiology. In this chapter, we build on the basic methodologies outlined in the previous chapter to address the question of how to model the invasion and spread of diseases in heterogeneous environments, without making

Wayne M. Getz; James O. Lloyd-Smith; Paul C. Cross; Shirli Bar-David; Philip L. Johnson; Travis C. Porco

7

An agent-based approach for modeling dynamics of contagious disease spread  

PubMed Central

Background The propagation of communicable diseases through a population is an inherent spatial and temporal process of great importance for modern society. For this reason a spatially explicit epidemiologic model of infectious disease is proposed for a greater understanding of the disease's spatial diffusion through a network of human contacts. Objective The objective of this study is to develop an agent-based modelling approach the integrates geographic information systems (GIS) to simulate the spread of a communicable disease in an urban environment, as a result of individuals' interactions in a geospatial context. Methods The methodology for simulating spatiotemporal dynamics of communicable disease propagation is presented and the model is implemented using measles outbreak in an urban environment as a case study. Individuals in a closed population are explicitly represented by agents associated to places where they interact with other agents. They are endowed with mobility, through a transportation network allowing them to move between places within the urban environment, in order to represent the spatial heterogeneity and the complexity involved in infectious diseases diffusion. The model is implemented on georeferenced land use dataset from Metro Vancouver and makes use of census data sets from Statistics Canada for the municipality of Burnaby, BC, Canada study site. Results The results provide insights into the application of the model to calculate ratios of susceptible/infected in specific time frames and urban environments, due to its ability to depict the disease progression based on individuals' interactions. It is demonstrated that the dynamic spatial interactions within the population lead to high numbers of exposed individuals who perform stationary activities in areas after they have finished commuting. As a result, the sick individuals are concentrated in geographical locations like schools and universities. Conclusion The GIS-agent based model designed for this study can be easily customized to study the disease spread dynamics of any other communicable disease by simply adjusting the modeled disease timeline and/or the infection model and modifying the transmission process. This type of simulations can help to improve comprehension of disease spread dynamics and to take better steps towards the prevention and control of an epidemic outbreak.

Perez, Liliana; Dragicevic, Suzana

2009-01-01

8

Early detection of contagious diseases  

Microsoft Academic Search

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

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

2011-01-01

9

The role of contagious disease in udder health  

PubMed Central

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.

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

2009-01-01

10

Invited review: The role of contagious disease in udder health.  

PubMed

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

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

2009-10-01

11

CONTAGIOUS DISEASE MODULE FOR THE JOINT EFFECTS MODEL  

Microsoft Academic Search

This presentation describes an approach to modeling the spread of contagious diseases across a population-at-risk represented by the LandScan database used by the Joint Effects Model (JEM). We are implementing two models of disease transmission for this effort: 1) a cohort-based Susceptible-Exposed-Infectious-Removed (SEIR) model that uses historical epidemics and simulated outbreaks as the basis for its time-dependent transmission functions and

Brian Adams; Jaideep Ray

2008-01-01

12

Intervention for contagious disease: Agent-based modeling and simulation  

Microsoft Academic Search

Many kinds of FRXQWHUmeasure could be adopted to contain or mitigate the spread of contagious disease; however, their effects are not very clear. We developed an agent-based model for assessment of those intervention policies. The population in a community was model as a large-scale artificial society, which is consistent with survey data in statisticDO? FKDUDFWHULVWLF. This artificial society is composed

Zhang Fa; Zhao Qiao-xia; Li Lu

2011-01-01

13

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

ERIC Educational Resources Information Center

|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…

Grosse, Susan J.

14

Irreversible Decision Making in Contagious Animal Disease Control under Uncertainty: An Illustration Using FMD in Brittany  

Microsoft Academic Search

The concept of irreversible investment is applied to highly contagious animal disease control when uncertainty about the spread of the disease is resolved over time. In comparison with the strategy of destroying infected herds, the vaccination programme causes additional losses that cannot be recovered. These sunk costs are thus irreversible. Therefore, the gain from waiting for new information, namely the

Olivier Mahul; Alexandre Gohin

1999-01-01

15

Should Persons with Contagious Diseases Be Barred from School?  

ERIC Educational Resources Information Center

|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…

Roe, Richard L.

1987-01-01

16

Contagious Equine Metritis: A Review  

PubMed Central

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

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

1979-01-01

17

What To Do When Contagious Disease Strikes Your School.  

ERIC Educational Resources Information Center

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

American Bar Association, Chicago, IL.

18

National identification and recording systems for contagious animal disease control  

Microsoft Academic Search

A conceptual framework was described for national identification and recording (I&R) systems, especially referring to the role in the control of highly contagious diseases in pigs. Subsequently, four different concepts of I&R systems were described: a current system meeting EU minimum standards, a revised system that will be introduced in several countries in the near future and two future concepts,

H. W. Saatkamp; R. Geers; J. P. T. M. Noordhuizen; A. A. Dijkhuizen; R. B. M. Huirne; V. Goedseels

1995-01-01

19

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

PubMed

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

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

2010-03-10

20

Contagious diseases in competitive sport: what are the risks?  

PubMed

Great concern is often expressed over the possibility of contagion among athletes in competitive sports, particularly sports with much person-to-person contact. Human immunodeficiency virus (HIV) is only the most notorious of infectious agents; potentially, other viruses, bacteria, and even fungi may be involved. Because of the concern, however, special attention is paid to HIV and hepatitis B infections. For most of the infections considered, the athlete is more at risk during activities off the playing field than while competing. Inclusion of immunizations against measles and hepatitis B among prematriculation immunization requirements (PIRs) for colleges and universities would eliminate these two diseases from the list of dangers to college athletes and all students. Education, rather than regulations, should remain the cornerstone in considering the risks to athletes from contagious diseases. PMID:11125637

Dorman, J M

2000-11-01

21

Contagious Capitalism  

Microsoft Academic Search

Is capitalism contagious? Since WWI, global foreign policy has treated economic freedom\\/repression like a virus that spreads between countries. Most recently, the ?domino theory? of freedom has played prominently in U.S. foreign policy toward Asia, Latin America, and the Caribbean during the Cold War, and the Middle East during the War on Terror. This paper investigates the spread of economic

Peter T. Leeson; Russell S. Sobel

2006-01-01

22

Contagious caprine pleuropneumonia: new aspects of an old disease.  

PubMed

Contagious caprine pleuropneumonia (CCPP), caused by Mycoplasma capricolum subsp. capripneumoniae, is a serious OIE-listed disease affecting goats in the Middle East, north and east Africa and Asia. Mortality and morbidity rates can be as high as 60% and 90%, respectively, when the disease first enters a territory, invariably through carrier animals. Recent detections of CCPP in Pakistan and Tajikistan are probably the result of improved diagnosis as the disease has been suspected there for many years, while those in Thrace in 2003 and Mauritius in 2009 represent new outbreaks. CCPP was thought to be highly host specific until recent outbreaks in wildlife species including gazelles and gerenuks show that the causative mycoplasma has broader specificity. Diagnosis was hampered by the fastidiousness of the causative mycoplasma but molecular-based tests like PCR have greatly improved detection. Rapid latex agglutination tests that can be performed at the penside are also available for antibody detection. Clinically affected animals respond to a range of antibiotics although it is unlikely that this results in complete elimination of the mycoplasma. Vaccines consisting of saponized organisms have been shown to be protective but the quality and efficacy may be variable. PMID:21951488

Nicholas, R; Churchward, C

2011-09-23

23

Finding evidence for local transmission of contagious disease in molecular epidemiological datasets.  

PubMed

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

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

2013-07-26

24

Supreme Court Holds That Contagious Diseases Are Handicaps.  

ERIC Educational Resources Information Center

|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…

Flygare, Thomas J.

1987-01-01

25

The North American Animal Disease Spread Model: A simulation model to assist decision making in evaluating animal disease incursions  

Microsoft Academic Search

The North American Animal Disease Spread Model is a stochastic, spatial, state-transition simulation model for the spread of highly contagious diseases of animals. It was developed with broad international support to assist policy development and decision making involving disease incursions. User-established parameters define model behavior in terms of disease progression; disease spread by animal-to-animal contact, contact with contaminated personnel or

Neil Harvey; Aaron Reeves; Mark A. Schoenbaum; Francisco J. Zagmutt-Vergara; Caroline Dubé; Ashley E. Hill; Barbara A. Corso; W. Bruce McNab; Claudia I. Cartwright; Mo D. Salman

2007-01-01

26

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

NASA Astrophysics Data System (ADS)

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.

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

2005-03-01

27

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

Microsoft Academic Search

The decision on which strategy to use in the control of contagious animal diseases involves complex trade-offs between multiple objectives. This paper describes a Multi Criteria Decision Making (MCDM) application to illustrate its potential support to policy makers in choosing the control strategy that best meets all of the conflicting interests. The presented application focused on the evaluation of alternative

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

2010-01-01

28

Contagious Diseases in Competitive Sport: What Are the Risks?  

ERIC Educational Resources Information Center

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.…

Dorman, John M.

2000-01-01

29

Contagious Diseases in Competitive Sport: What Are the Risks?  

ERIC Educational Resources Information Center

|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.…

Dorman, John M.

2000-01-01

30

Contagious colonial diseases in Hergé's The adventures of Tintin  

Microsoft Academic Search

This article analyses the portrayal of illness and disease in two well?known Tintin books that were published in the late 1940s. It underlines how work from Hergé in this period continued to be marked with an imperialist mindset. In particular, it is important to appreciate that publications such as Les 7 Boules de cristal and Le Temple du soleil lend

Hugo Frey

2004-01-01

31

Contagious Rhythm: Infectious Diseases of 20th Century Musicians  

PubMed Central

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.

Sartin, Jeffrey S.

2010-01-01

32

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

PubMed

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

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

2010-07-14

33

A mechanistic model of infection: why duration and intensity of contacts should be included in models of disease spread  

Microsoft Academic Search

BACKGROUND: Mathematical models and simulations of disease spread often assume a constant per-contact transmission probability. This assumption ignores the heterogeneity in transmission probabilities, e.g. due to the varying intensity and duration of potentially contagious contacts. Ignoring such heterogeneities might lead to erroneous conclusions from simulation results. In this paper, we show how a mechanistic model of disease transmission differs from

Timo Smieszek

2009-01-01

34

Nosocomial Spread of Viral Disease  

PubMed Central

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.

Aitken, Celia; Jeffries, Donald J.

2001-01-01

35

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

PubMed Central

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

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

2013-01-01

36

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

PubMed

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

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

2013-03-11

37

The SIR Model for Spread of Disease  

NSDL National Science Digital Library

The purpose of this module is to develop the SIR Model for the spread of an infectious disease, including the concepts of contact number and herd immunity; to develop a version of Euler's Method for solving a system of differential equations.

Smith, David; Moore, Lang

2000-09-22

38

Spread of epidemic disease on networks  

Microsoft Academic Search

The study of social networks, and in particular the spread of disease on\\u000anetworks, has attracted considerable recent attention in the physics community.\\u000aIn this paper, we show that a large class of standard epidemiological models,\\u000athe so-called susceptible\\/infective\\/removed (SIR) models can be solved exactly\\u000aon a wide variety of networks. In addition to the standard but unrealistic case\\u000aof

M. E. J. Newman

2002-01-01

39

The SIR Model for Spread of Disease  

NSDL National Science Digital Library

Created by Lang Moore and David Smith for the Connected Curriculum Project, the purpose of this module is to develop the SIR Model for the spread of an infectious disease, including the concepts of contact number and herd immunity; to develop a version of Euler's Method for solving a system of differential equations. This is one lesson within a larger set of learning modules hosted by Duke University.

Smith, David; Moore, Lang

2010-06-18

40

Contagious cancer.  

PubMed

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

Welsh, James S

2011-01-06

41

Introduction of contagious animal diseases into The Netherlands: elicitation of expert opinions  

Microsoft Academic Search

This paper describes an experiment aimed at the derivation of information on Foot-and-Mouth Disease, Classical and African Swine Fever, Swine Vesicular Disease, Newcastle Disease and Avian Influenza to be used in an economic model to simulate introduction of a virus into the Netherlands. Several elicitation techniques, including three-point estimation, Conjoint analysis and ELI were used in the experiment. Three-point estimation

H. S. Horst; A. A. Dijkhuizen; R. B. M. Huirne; P. W De Leeuw

1998-01-01

42

Spreading of sexually transmitted diseases in heterosexual populations  

Microsoft Academic Search

The spread of sexually transmitted diseases (e.g., chlamydia, syphilis, gonorrhea, HIV, etc.) across populations is a major concern for scientists and health agencies. In this context, both the data collection on sexual contact networks and the modeling of disease spreading are intensive contributions to the search for effective immunization policies. Here, the spreading of sexually transmitted diseases on bipartite scale-free

Jesús Gómez-Gardeñes; Vito Latora; Yamir Moreno; Elio V. Profumo

2008-01-01

43

Is “cost diseasecontagious? The case of early music ensembles  

Microsoft Academic Search

The article aims to supplement traditional explanations of why performing arts institutions tend to run a deficit. The case of early music ensembles shows that the traditionally cited mechanisms do not suffice to explain why these institutions catch Baumol’s “cost disease.” Baumol’s model may be supplemented by another, based on two related hypotheses: the deepening deficit of early music ensembles

Pierre François

2007-01-01

44

Spread of epidemic disease on networks  

NASA Astrophysics Data System (ADS)

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

Newman, M. E.

2002-07-01

45

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

NASA Astrophysics Data System (ADS)

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.

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

46

Contagious yawning in chimpanzees.  

PubMed Central

Six adult female chimpanzees were shown video scenes of chimpanzees repeatedly yawning or of chimpanzees showing open-mouth facial expressions that were not yawns. Two out of the six females showed significantly higher frequencies of yawning in response to yawn videos; no chimpanzees showed the inverse. Three infant chimpanzees that accompanied their mothers did not yawn at all. These data are highly reminiscent of the contagious yawning effects reported for humans. Contagious yawning is thought to be based on the capacity for empathy. Contagious yawning in chimpanzees provides further evidence that these apes may possess advanced self-awareness and empathic abilities.

Anderson, James R; Myowa-Yamakoshi, Masako; Matsuzawa, Tetsuro

2004-01-01

47

Contagious yawning in chimpanzees.  

PubMed

Six adult female chimpanzees were shown video scenes of chimpanzees repeatedly yawning or of chimpanzees showing open-mouth facial expressions that were not yawns. Two out of the six females showed significantly higher frequencies of yawning in response to yawn videos; no chimpanzees showed the inverse. Three infant chimpanzees that accompanied their mothers did not yawn at all. These data are highly reminiscent of the contagious yawning effects reported for humans. Contagious yawning is thought to be based on the capacity for empathy. Contagious yawning in chimpanzees provides further evidence that these apes may possess advanced self-awareness and empathic abilities. PMID:15801606

Anderson, James R; Myowa-Yamakoshi, Masako; Matsuzawa, Tetsuro

2004-12-01

48

Global disease spread: Statistics and estimation of arrival times  

Microsoft Academic Search

We study metapopulation models for the spread of epidemics in which different subpopulations (cities) are connected by fluxes of individuals (travelers). This framework allows one to describe the spread of a disease on a large scale and we focus here on the computation of the arrival time of a disease as a function of the properties of the seed of

Aurelien Gautreau; Alain Barrat; Marc Barthelemy

2008-01-01

49

Contagious yawning and the brain  

Microsoft Academic Search

Contagious yawning, the onset of a yawn triggered by seeing, hearing, reading, or thinking about another person yawn is a well-documented phenomenon. The mechanisms that drive contagious yawning are as yet unknown, but there is recent evidence of a link between contagious yawning and self-processing (S.M. Platek, S.R. Critton, T.E. Myers, G.G. Gallup Jr., Contagious yawning: the role of self-awareness

Steven M. Platek; Feroze B. Mohamed; Gordon G. Gallup Jr.

2005-01-01

50

Contagious Acute Gastrointestinal Infections  

Microsoft Academic Search

n our ever-shrinking world, widespread media coverage of in- fections, ranging from the severe acute respiratory syndrome (also known as SARS) and influenza in Asia to acute gastroenteritis on cruise ships and outbreaks in day-care centers in the United States, has raised public interest in contagious diseas- es to new heights. Our purpose in this article is to examine contagion

Daniel M. Musher; Benjamin L. Musher

2004-01-01

51

Contiguous pattern spreading in patients with Hodgkin's disease  

Microsoft Academic Search

Background: In 1966, Rosenberg and Kaplan hypothesized that Hodgkin's disease (HD) arises at a discrete primary site and subsequently spreads in a predictable manner via functionally contiguous lymph nodes. However, their results were not statistically evident. It was our aim to describe the spreading in the lymphatic system more precisely and to confirm their postulate.Methods: Between 1971 and 1992, 297

Stephan Ludwig Roth; Horst Sack; Klaus Havemann; Reinhart Willers; Béla Kocsis; Viola Schumacher

1998-01-01

52

A Cellular Automaton Framework for Infectious Disease Spread Simulation  

PubMed Central

In this paper, a cellular automaton framework for processing the spatiotemporal spread of infectious diseases is presented. The developed environment simulates and visualizes how infectious diseases might spread, and hence provides a powerful instrument for health care organizations to generate disease prevention and contingency plans. In this study, the outbreak of an avian flu like virus was modeled in the state of Tyrol, and various scenarios such as quarantine, effect of different medications on viral spread and changes of social behavior were simulated. The proposed framework is implemented using the programming language Java. The set up of the simulation environment requires specification of the disease parameters and the geographical information using a population density colored map, enriched with demographic data. The results of the numerical simulations and the analysis of the computed parameters will be used to get a deeper understanding of how the disease spreading mechanisms work, and how to protect the population from contracting the disease. Strategies for optimization of medical treatment and vaccination regimens will also be investigated using our cellular automaton framework. In this study, six different scenarios were simulated. It showed that geographical barriers may help to slow down the spread of an infectious disease, however, when an aggressive and deadly communicable disease spreads, only quarantine and controlled medical treatment are able to stop the outbreak, if at all.

Pfeifer, Bernhard; Kugler, Karl; Tejada, Maria M; Baumgartner, Christian; Seger, Michael; Osl, Melanie; Netzer, Michael; Handler, Michael; Dander, Andreas; Wurz, Manfred; Graber, Armin; Tilg, Bernhard

2008-01-01

53

Models for the spread of universally fatal diseases  

Microsoft Academic Search

In the formulation of models of S-I-R type for the spread of communicable diseases it is necessary to distinguish between diseases with recovery with full immunity and diseases with permanent removal by death. We consider models which include nonlinear population dynamics with permanent removal. The principal result is that the stability of endemic equilibrium may depend on the population dynamics

F. Brauer

1990-01-01

54

Protein aggregate spreading in neurodegenerative diseases: Problems and perspectives  

Microsoft Academic Search

Progressive accumulation of specific protein aggregates is a defining feature of many major neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, fronto-temporal dementia, Huntington's disease, and Creutzfeldt–Jakob disease (CJD). Findings from several recent studies have suggested that aggregation-prone proteins, such as tau, ?-synuclein, polyglutamine-containing proteins, and amyloid-?, can spread to other cells and brain regions, a phenomenon considered unique to prion

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

2011-01-01

55

Global Transport Networks and Infectious Disease Spread  

PubMed Central

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.

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

2011-01-01

56

Risk of Disease Spread through Bioterrorism  

SciTech Connect

Bioterrorism is seen as a clear and present danger, although historically, acts of bioterrorism have been relatively unpredictable, rare and, thus far, small-scale events. The risk of an event is elevated by increasing contact among species and a global connectivity that provides rapid dissemination of infectious diseases regardless of origin. Virtually any pathogenic microbe could be used by bioterrorists. An attack may be difficult to distinguish from a naturally occurring infectious disease outbreak; however, consequences are likely to be similar. The U.S. agricultural sector is extremely vulnerable to bioterrorist attacks because our animals and plants have little or no innate resistance to foreign pathogens and are not vaccinated or otherwise protected against these diseases. It is also important to note that weapons or delivery systems are not an issue because the animals and plants themselves are the primary vector for transferring agents. Most bioterrorism agents are zoonotic in origin, thus an attack on animal populations could pose a health risk to humans. Additionally, disease outbreaks resulting from bioterrorism could jump to wildlife species, persist in the environment, replace locally adapted enzootic strains, expand their range, or emerge as a new zoonotic disease in naïve human and animal populations.

Weller, Richard E.

2006-08-01

57

Epitope spreading in immune-mediated diseases: implications for immunotherapy  

Microsoft Academic Search

Evidence continues to accumulate supporting the hypothesis that tissue damage during an immune response can lead to the priming of self-reactive T and\\/or B lymphocytes, regardless of the specificity of the initial insult. This review will focus primarily on epitope spreading at the T-cell level. Understanding the cellular and molecular basis of epitope spreading in various chronic immune-mediated human diseases

Carol L. Vanderlugt; Stephen D. Miller

2002-01-01

58

On the origin and spread of Dupuytren's disease  

Microsoft Academic Search

The first author to suggest an origin and spread of Dupuytren's disease was Early who wrote in 1962, “If one postulates the condition as having arisen in one particular racial group (the Nordic for example) then the variable distribution in other parts of the world might be explained on the basis of migration from that group.” Dupuytren's disease is currently

Robert M. McFarlane

2002-01-01

59

? Several foreign animal diseases present a significant threat to the US cattle industry. The status of vaccines for high priority foreign animal diseases of cattle will be presented; including Foot and Mouth Disease, Rift Valley Fever, Rinderpest, Contagious Bovine Pleuropneumonia, and Heartwater  

Microsoft Academic Search

KEY POINTS ? Of the high priority foreign animal diseases of cattle, vaccines are only available in the US for Foot and Mouth Disease. ? Research and development is urgently needed for improved vaccines for FMD, Rift Valley Fever, Contagious Bovine Pleuropneumonia, and Heartwater. OVERVIEW OF THE ISSUE The US has a vaccine bank for Foot and Mouth Disease and

James A. Roth

60

Contagious caprine pleuropneumonia and Mannheimia haemolytica-associated acute respiratory disease of goats and sheep in Afar Region, Ethiopia  

Microsoft Academic Search

Summary In April 2002, an investigation into an outbreak of acute respiratory disease in goats and sheep in Milae (Afar), Ethiopia was conducted. The investigation involved 4 flocks (722 sheep and 750 goats in total) and comprised the disease history, clinical and post-mortem examination, and microbiological analysis of nasal swabs, lung lesions, and pleural fluid samples. Clinically diseased animals exhibited

G. Shiferaw; S. Tariku; G. Ayelet; Z. Abebe

61

LETTER: Arrival time statistics in global disease spread  

Microsoft Academic Search

Metapopulation models describing cities with different populations coupled by the travel of individuals are of great importance in the understanding of disease spread on a large scale. An important example is the Rvachev Longini model which is widely used in computational epidemiology. Few analytical results are, however, available and, in particular, little is known about paths followed by epidemics and

Aurélien Gautreau; Alain Barrat; Marc Barthélemy

2007-01-01

62

Should prisons ease drug prohibition to help reduce disease spread?  

PubMed Central

A session at this summer's international AIDS conference in Vancouver focused on the use of harm-reduction policies to reduce the spread of disease caused by injection drug use. The concept, which is gaining popularity, focuses on the need to limit the harm caused by drug use, not on elimination of the problem. Images p1490-a

Kent, H

1996-01-01

63

LETTER: Arrival time statistics in global disease spread  

NASA Astrophysics Data System (ADS)

Metapopulation models describing cities with different populations coupled by the travel of individuals are of great importance in the understanding of disease spread on a large scale. An important example is the Rvachev Longini model which is widely used in computational epidemiology. Few analytical results are, however, available and, in particular, little is known about paths followed by epidemics and disease arrival times. We study the arrival time of a disease in a city as a function of the starting seed of the epidemics. We propose an analytical ansatz, test it in the case of a spread on the worldwide air-transportation network, and show that it predicts accurately the arrival order of a disease in worldwide cities.

Gautreau, Aurélien; Barrat, Alain; Barthélemy, Marc

2007-09-01

64

A mechanistic model of infection: why duration and intensity of contacts should be included in models of disease spread  

PubMed Central

Background Mathematical models and simulations of disease spread often assume a constant per-contact transmission probability. This assumption ignores the heterogeneity in transmission probabilities, e.g. due to the varying intensity and duration of potentially contagious contacts. Ignoring such heterogeneities might lead to erroneous conclusions from simulation results. In this paper, we show how a mechanistic model of disease transmission differs from this commonly used assumption of a constant per-contact transmission probability. Methods We present an exposure-based, mechanistic model of disease transmission that reflects heterogeneities in contact duration and intensity. Based on empirical contact data, we calculate the expected number of secondary cases induced by an infector (i) for the mechanistic model and (ii) under the classical assumption of a constant per-contact transmission probability. The results of both approaches are compared for different basic reproduction numbers R0. Results The outcomes of the mechanistic model differ significantly from those of the assumption of a constant per-contact transmission probability. In particular, cases with many different contacts have much lower expected numbers of secondary cases when using the mechanistic model instead of the common assumption. This is due to the fact that the proportion of long, intensive contacts decreases in the contact dataset with an increasing total number of contacts. Conclusion The importance of highly connected individuals, so-called super-spreaders, for disease spread seems to be overestimated when a constant per-contact transmission probability is assumed. This holds particularly for diseases with low basic reproduction numbers. Simulations of disease spread should weight contacts by duration and intensity.

2009-01-01

65

Disease spreading with epidemic alert on small-world networks  

NASA Astrophysics Data System (ADS)

Base on two-dimension small-world networks, a susceptible-infected model with epidemic alert is proposed in this Letter. In this model, if some parts of the network are alarmed as dangerous, a fraction of edges between the alarmed parts and others will be removed, and two cases of alerting rules that the degree and frequency of contacts kept unchanged are considered respectively. The numerical simulations show that the spreading velocity is reduced by the accurate and timely epidemic alert, and the more accurate and timely, the stronger the deceleration effect. This model indicates that to broadcast epidemic alert timely is helpful and necessary in the control of epidemic spreading, and in agreement with the general view of epidemic alert. This work is helpful to understand the effects of epidemic alert on disease spreading.

Han, Xiao-Pu

2007-05-01

66

Simulating disease spread within a geographic information system environment.  

PubMed

Simulation modelling is a tool that can be used to investigate the effectiveness and efficiency of exotic disease control, eradication and surveillance strategies. The Australian Government Department of Agriculture, Fisheries and Forestry (DAFF) has been involved with disease simulation modelling for more than 10 years. Although the focus has been on foot and mouth disease, models are now being developed for avian influenza, classical swine fever and other diseases. Recent models are spatially explicit, and incorporate a range of animal species and production types. The models also encompass a range of disease transmission pathways, including farm-to-farm animal movements, movements through saleyards, windborne spread, spread by feral animals and the less well-defined phenomenon of local spread. The DAFF spatial models are unique in that they are developed within the environment of a geographic information system (GIS) - MapBasic/MapInfo. This simplifies the spatial elements of their code and improves their ability to handle spatial data layers. Such layers vary, but may include the following: farm locations or boundaries; masks identifying grazing; cropping and non-agricultural land; water bodies and waterways; population centres, administrative boundaries and roadways; vegetation and other land cover masks; and, where relevant, elevation. The GIS environment also provides immediate access to sophisticated maps and tabular outputs. PMID:20422538

Beckett, Samuel; Garner, M Graeme

67

Aerial dispersal and multiple-scale spread of epidemic disease.  

PubMed

Disease spread has traditionally been described as a traveling wave of constant velocity. However, aerially dispersed pathogens capable of long-distance dispersal often have dispersal gradients with extended tails that could result in acceleration of the epidemic front. We evaluated empirical data with a simple model of disease spread that incorporates logistic growth in time with an inverse power function for dispersal. The scale invariance of the power law dispersal function implies its applicability at any spatial scale; indeed, the model successfully described epidemics ranging over six orders of magnitude, from experimental field plots to continental-scale epidemics of both plant and animal diseases. The distance traveled by epidemic fronts approximately doubled per unit time, velocity increased linearly with distance (slope ~(1/2)), and the exponent of the inverse power law was approximately 2. We found that it also may be possible to scale epidemics to account for initial outbreak focus size and the frequency of susceptible hosts. These relationships improve understanding of the geographic spread of emerging diseases, and facilitate the development of methods for predicting and preventing epidemics of plants, animals, and humans caused by pathogens that are capable of long-distance dispersal. PMID:20155301

Mundt, Christopher C; Sackett, Kathryn E; Wallace, Larae D; Cowger, Christina; Dudley, Joseph P

2010-02-13

68

A Large Speculator in Contagious Currency Crises: A Single \\  

Microsoft Academic Search

This paper studies the implications of the presence of a large speculator like George Soros during a contagious currency crisis. The model proposes a new contagion channel and shows how a currency crisis can spread from one country to another even when these countries are totally unrelated in terms of economic fundamentals. This model enables us to distinguish be- tween

Kenshi Taketa

69

Tuberculosis as Occupational Disease of Medical and Nursing Personnel and Its Prevention.  

National Technical Information Service (NTIS)

Tuberculosis is one of the most wide spread contagious diseases, but it is certainly not all people who catch tuberculosis. Many people experience their first tubercular infection without even knowing it and never really become ill with tuberculosis for t...

O. Brinkmann

1965-01-01

70

Protein aggregate spreading in neurodegenerative diseases: problems and perspectives.  

PubMed

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

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

2011-05-20

71

The landscape genetics of infectious disease emergence and spread  

PubMed Central

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.

Biek, Roman; Real, Leslie A.

2011-01-01

72

Contagious yawning and the brain.  

PubMed

Contagious yawning, the onset of a yawn triggered by seeing, hearing, reading, or thinking about another person yawn is a well-documented phenomenon. The mechanisms that drive contagious yawning are as yet unknown, but there is recent evidence of a link between contagious yawning and self-processing (S.M. Platek, S.R. Critton, T.E. Myers, G.G. Gallup Jr., Contagious yawning: the role of self-awareness and mental state attribution, Cogn. Brain Res. 17 (2003) 223-227.) that is negatively impacted by schizotypal personality traits. The neural substrates involved in contagious yawning, however, are unknown. Here, using fMRI, we show that viewing someone yawn evokes unique neural activity in the posterior cingulate and precuneus. Because of the role these areas play in self-processing (e.g., self-referential processing, theory of mind, autobiographical memory), our findings provide further support for the hypothesis that contagious yawning may be part of a neural network involved in empathy. PMID:15820652

Platek, Steven M; Mohamed, Feroze B; Gallup, Gordon G

2005-01-26

73

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

SciTech Connect

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.

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

74

Controlling disease spread on networks with incomplete knowledge  

NASA Astrophysics Data System (ADS)

Models for control of highly infectious diseases on local, small-world, and scale-free networks are considered, with only partial information accessible about the status of individuals and their connections. We consider a case when individuals can be infectious before showing symptoms and thus before detection. For small to moderately severe incidence of infection with a small number of nonlocal links, it is possible to control disease spread by using purely local methods applied in a neighborhood centered around a detected infectious individual. There exists an optimal radius for such a control neighborhood leading to the lowest severity of the epidemic in terms of economic costs associated with disease and treatment. The efficiency of a local control strategy is very sensitive to the choice of the radius. Below the optimal radius, the local strategy is unsuccessful; the disease spreads throughout the system, necessitating treatment of the whole population. At the other extreme, a strategy involving a neighborhood that is too large controls the disease but is wasteful of resources. It is not possible to stop an epidemic on scale-free networks by preventive actions, unless a large proportion of the population is treated.

Dybiec, B.; Kleczkowski, A.; Gilligan, C. A.

2004-12-01

75

Spreading disease: a controversy concerning the metaphysics of disease.  

PubMed

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. PMID:10326330

D'Amico, R

1998-01-01

76

Genetic influence on disease spread following arrival of infected carriers.  

PubMed

Epidemiology in host meta-populations depends on parasite ability to disperse between, establish and persist in distinct sub-populations of hosts. We studied the genetic factors determining the short-term establishment, and long-term maintenance, of pathogens introduced by infected hosts (i.e. carriers) into recipient populations. We used experimental populations of the freshwater ciliate Paramecium caudatum and its bacterial parasite Holospora undulata. Parasite short-term spread (approximately one horizontal transmission cycle) was affected mainly by carrier genotype, and its interactions with parasite and recipient genotypes. By contrast, parasite longer term spread (2-3 horizontal transmission cycles) was mostly determined by parasite isolate. Importantly, measures of parasite short-term success (reproductive number, R) were not good predictors for longer term prevalence, probably because of the specific interactions between host and parasite genotypes. Analogous to variation in vectorial capacity and super-spreader occurrence, two crucial components of epidemiology, we show that carrier genotype can also affect disease spread within meta-populations. PMID:22221658

Fellous, Simon; Duncan, Alison B; Quillery, Elsa; Vale, Pedro F; Kaltz, Oliver

2012-01-05

77

Optimizing surveillance for livestock disease spreading through animal movements.  

PubMed

The spatial propagation of many livestock infectious diseases critically depends on the animal movements among premises; so the knowledge of movement data may help us to detect, manage and control an outbreak. The identification of robust spreading features of the system is however hampered by the temporal dimension characterizing population interactions through movements. Traditional centrality measures do not provide relevant information as results strongly fluctuate in time and outbreak properties heavily depend on geotemporal initial conditions. By focusing on the case study of cattle displacements in Italy, we aim at characterizing livestock epidemics in terms of robust features useful for planning and control, to deal with temporal fluctuations, sensitivity to initial conditions and missing information during an outbreak. Through spatial disease simulations, we detect spreading paths that are stable across different initial conditions, allowing the clustering of the seeds and reducing the epidemic variability. Paths also allow us to identify premises, called sentinels, having a large probability of being infected and providing critical information on the outbreak origin, as encoded in the clusters. This novel procedure provides a general framework that can be applied to specific diseases, for aiding risk assessment analysis and informing the design of optimal surveillance systems. PMID:22728387

Bajardi, Paolo; Barrat, Alain; Savini, Lara; Colizza, Vittoria

2012-06-22

78

Corruption and Spread of Pathogenic Proteins in Neurodegenerative Diseases*  

PubMed Central

With advancing age, the brain becomes increasingly susceptible to neurodegenerative diseases, most of which are characterized by the misfolding and errant aggregation of certain proteins. The induction of aggregation involves a crystallization-like seeding mechanism by which a specific protein is structurally corrupted by its misfolded conformer. The latest research indicates that, once formed, proteopathic seeds can spread from one locale to another via cellular uptake, transport, and release. Impeding this process could represent a unified therapeutic strategy for slowing the progression of a wide range of currently intractable disorders.

Walker, Lary C.; LeVine, Harry

2012-01-01

79

Corruption and spread of pathogenic proteins in neurodegenerative diseases.  

PubMed

With advancing age, the brain becomes increasingly susceptible to neurodegenerative diseases, most of which are characterized by the misfolding and errant aggregation of certain proteins. The induction of aggregation involves a crystallization-like seeding mechanism by which a specific protein is structurally corrupted by its misfolded conformer. The latest research indicates that, once formed, proteopathic seeds can spread from one locale to another via cellular uptake, transport, and release. Impeding this process could represent a unified therapeutic strategy for slowing the progression of a wide range of currently intractable disorders. PMID:22879600

Walker, Lary C; LeVine, Harry

2012-08-09

80

The Cost of Simplifying Air Travel When Modeling Disease Spread  

PubMed Central

Background Air travel plays a key role in the spread of many pathogens. Modeling the long distance spread of infectious disease in these cases requires an air travel model. Highly detailed air transportation models can be over determined and computationally problematic. We compared the predictions of a simplified air transport model with those of a model of all routes and assessed the impact of differences on models of infectious disease. Methodology/Principal Findings Using U.S. ticket data from 2007, we compared a simplified “pipe” model, in which individuals flow in and out of the air transport system based on the number of arrivals and departures from a given airport, to a fully saturated model where all routes are modeled individually. We also compared the pipe model to a “gravity” model where the probability of travel is scaled by physical distance; the gravity model did not differ significantly from the pipe model. The pipe model roughly approximated actual air travel, but tended to overestimate the number of trips between small airports and underestimate travel between major east and west coast airports. For most routes, the maximum number of false (or missed) introductions of disease is small (<1 per day) but for a few routes this rate is greatly underestimated by the pipe model. Conclusions/Significance If our interest is in large scale regional and national effects of disease, the simplified pipe model may be adequate. If we are interested in specific effects of interventions on particular air routes or the time for the disease to reach a particular location, a more complex point-to-point model will be more accurate. For many problems a hybrid model that independently models some frequently traveled routes may be the best choice. Regardless of the model used, the effect of simplifications and sensitivity to errors in parameter estimation should be analyzed.

Lessler, Justin; Kaufman, James H.; Ford, Daniel A.; Douglas, Judith V.

2009-01-01

81

Prevention of spread of communicable disease by air travel.  

PubMed

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. PMID:19601500

Evans, Anthony D; Thibeault, Claude

2009-07-01

82

Spreading of periodic diseases and synchronization phenomena on networks  

NASA Astrophysics Data System (ADS)

In this paper, we investigate numerically the Susceptible-Infected-Recovered-Susceptible (SIRS) epidemic model on an exponential network generated by a preferential attachment procedure. The discrete SIRS model considers two main parameters: the duration ?0 of the complete infection-recovery cycle and the duration ?I of infection. A permanent source of infection I0 has also been introduced in order to avoid the vanishing of the disease in the SIRS model. The fraction of infected agents is found to oscillate with a period T??0. Simulations reveal that the average fraction of infected agents depends on I0 and ?I/?0. A maximum of synchronization of infected agents, i.e. a maximum amplitude of periodic spreading oscillations, is found to occur when the ratio ?I/?0 is slightly smaller than 1/2. The model is in agreement with the general observation that an outbreak corresponds to high ?I/?0 values.

Ababou, M.; Vandewalle, N.; Moussa, N.; El Bouziani, M.; Ludewig, F.

2013-05-01

83

Does genetic diversity limit disease spread in natural host populations?  

PubMed Central

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.'

King, K C; Lively, C M

2012-01-01

84

Contagious Yawning in Autistic and Typical Development  

ERIC Educational Resources Information Center

|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…

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

2010-01-01

85

Update on cutaneous manifestations of infectious diseases.  

PubMed

Many emerging pathogens present in the skin and are of interest to dermatologists. Recent epidemics of measles, avian flu, and SARS demonstrated how an organism can rapidly spread worldwide because of airline travel. Travelers are often contagious before they are aware that they have the disease, contributing to the spread. This article reviews bacterial, mycobacterial, fungal, and viral pathogens important to dermatologists. PMID:19932331

Elston, Dirk M

2009-11-01

86

Investigating Disease Spread between Two Assessment Dates with Permutation Tests on a Lattice  

Microsoft Academic Search

Thébaud, G., Peyrard, N., Dallot, S., Calonnec, A., and Labonne, G. 2005. Investigating disease spread between two assessment dates with permutation tests on a lattice. Phytopathology 95:1453-1461. Mapping and analyzing the disease status of individual plants within a study area at successive dates can give insight into the processes involved in the spread of a disease. We propose a permutation

Gaël Thébaud; Nathalie Peyrard; Sylvie Dallot; Agnès Calonnec; Gérard Labonne

2005-01-01

87

[Reemergence of contagious bovine pleuropneumonia in Senegal].  

PubMed

The authors have described an epizootic infection of contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides biotype Small Colony (MmmSC), that has affected Ndama bovine in Lounthy village, a locality based in Bala city in the Eastern part of Senegal, during the post-rainy season in November 2012. After the cessation of vaccination, a hotbed of suspicion of CBPP was identified on November 3rd 2012 in the village of Lounthy: out of the total of 98 cattle, 13 animals were sick and 5 of them died. These studies have been done according to clinical aspects, serological, bacteriological and molecular analysis of the samples. This reemergent disease will give new orientations for CBPP control in Senegal, where it was supposed the disease has been eradicated since 2005. PMID:23832316

Mbengue, M; Diallo, A A; Lo, F T; Lo, M M; Diop, M; Seck, P S; Samb, Y; Diouf, M; Thiongane, Y

2013-07-05

88

Developmental and comparative perspectives of contagious yawning.  

PubMed

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. PMID:20357469

Senju, Atsushi

2010-03-26

89

Contagious yawning in autistic and typical development.  

PubMed

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. PMID:20840244

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

90

Role of a Novel Antioncogene that Prevents Metastatic Spread of Disease.  

National Technical Information Service (NTIS)

The aim of this project is to determine the role of a novel antioncogene (nm23) in the spread of cancer. We propose that nm23 prevents metastatic spread of disease by down regulation of proteolytic activity that is necessary for tumor cells to migrate to ...

T. E. Kute

1995-01-01

91

Risk maps for the spread of highly pathogenic avian influenza in poultry  

Microsoft Academic Search

Devastating epidemics of highly contagious animal diseases like avian influenza, classical swine fever, and foot-and-mouth disease underline the need for improved understanding of the factors promoting the spread of these pathogens. Here we present a spatial analysis of the between-farm transmission of a highly pathogenic H7N7 avian influenza virus that caused a large epidemic in The Netherlands in 2003. We

Gert Jan Boender; Thomas J. Hagenaars; Annemarie Bouma; H. A. Nodelijk; Armin R. W. Elbers; Mart C. M. de Jong; Michiel van Boven

2007-01-01

92

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

Microsoft Academic Search

Livestock movements in Great Britain (GB) are well recorded and are a unique record of the network of connections among livestock-holding locations. These connections can be critical for disease spread, as in the 2001 epidemic of foot-and-mouth disease (FMD) in the UK. Here, the movement data are used to construct an individual-farm-based model of the initial spread of FMD in

D. M. Green; I. Z. Kiss; R. R. Kao

2006-01-01

93

PORCINE CONTAGIOUS PLEUROPNEUMONIA. I. EXPERIMENTAL TRANSMISSION, ETIOLOGY, AND PATHOLOGY.  

PubMed

An acute frequently rapidly fatal respiratory illness occurring as an epidemic disease in Argentine swine has been shown to have a bacterium of the genus Hemophilus as its causative agent. This organism, for which the name Hemophilus pleuropneumoniae is suggested, causes a singular, fulminating pleuropneumonia in experimental swine. The very marked effectiveness of H. pleuropneumoniae as a respiratory pathogen contrasts strikingly with the relatively mild pathogenicity of the well known swine Hemophilus, H. influenzae suis, which, in concert with a virus, causes a less highly fatal respiratory ailment, swine influenza. Porcine contagious pleuropneumonia (PCP) is contagious under experimental conditions. In the pathogenesis of the disease, histopathological studies of early cases suggest that the lymphatics of the lung and pleura may be primarily involved and that the pneumonia and pleuritis then proceed from these initial sites of reaction. PMID:14129707

SHOPE, R E

1964-03-01

94

Modeling dynamic and network heterogeneities in the spread of sexually transmitted diseases  

Microsoft Academic Search

A wide range of communicable human diseases can be considered as spreading through a network of possible transmission routes. The implied network structure is vital in determining disease dynamics, especially when the average number of connections per individual is small as is the case for many sexually transmitted diseases (STDs). Here we develop an intuitive mathematical framework to deal with

Ken T. D. Eames; Matt J. Keeling

2002-01-01

95

Epidemiology of the spread of viral diseases under aquaculture.  

PubMed

Aquaculture production is increasing rapidly worldwide. However, production has been associated with the emergence of several novel diseases, including viral diseases, that have caused serious problems for producers. Using examples largely from salmon farming in Scotland I review briefly the factors that allow transmission to occur in aquaculture. These include transmission through the water, which is relatively local to the infected farm, and anthropogenic transports (such as transport of fish between sites) that may occur over very long distances. A Disease Management Area (DMA) approach, as developed in Scotland to fight infectious salmon anaemia, can be effective at reducing pathogen transmission and hence disease emergence. PMID:23206337

Murray, Alexander G

2012-12-01

96

Spatial scaling relationships for spread of disease caused by a wind-dispersed plant pathogen  

PubMed Central

Spatial scale is of great importance to understanding the spread of organisms exhibiting long-distance dispersal (LDD). We tested whether epidemics spread in direct proportion to the size of the host population and size of the initial disease focus. This was done through analysis of a previous study of the effects of landscape heterogeneity variables on the spread of accelerating epidemics of wheat (Triticum aestivum) stripe rust, caused by the fungus Puccinia striiformis f. sp. tritici. End-of-season disease gradients were constructed by estimating disease prevalence at regular distances from artificially inoculated foci of different sizes, in field plots of different dimensions. In one set of comparisons, all linear dimensions (plot width and length, focus width and length, and distance between observation points) differed by a factor of four. Disease spread was substantially greater in large plot/large focus treatments than in small plot/small focus treatments. However, when disease gradients were plotted using focus width as the unit distance, they were found to be highly similar, suggesting a proportional relationship between focus or plot size and disease spread. A similar relationship held when comparing same-size plots inoculated with different-sized foci, an indication that focus size is the driver of this proportionality. Our results suggest that power law dispersal of LDD organisms results in scale-invariant relationships, which are useful for better understanding spatial spread of biological invasions, extrapolating results from small-scale experiments to invasions spreading over larger scales, and predicting speed and pattern of spread as an invasion expands.

Mundt, Christopher C.; Sackett, Kathryn E.

2013-01-01

97

Bibliography of Classical and Contagious Discrete Distributions.  

National Technical Information Service (NTIS)

The report provides a bibliography of classical and contagious discrete distributions which lists 2113 publications in statistics and probability discussing discrete distributions in general. Publications in other fields discussing applications of these d...

G. P. Patil S. W. Joshi

1966-01-01

98

Modelling disease spread in dispersal networks at two levels.  

PubMed

A network model at both the population and individual levels, which simulates both between-patch and within-patch dynamics, is proposed. We investigated the effects of dispersal networks and distribution of local dynamics on the outcome of an epidemic at the population level. Numerical studies show that disease control on random networks may be easier than on small-world networks, depending on the initial distribution of the local dynamics. Spatially separating instead of gathering patches where disease locally persists is beneficial to global disease control if dispersal networks are a type of small-world networks. Dispersal networks with higher degree lead to a higher mean value of R0. Furthermore, irregularity of network and randomization are beneficial to disease stabilization and greatly affect the resulting global dynamics. PMID:20439307

Xiao, Yanni; Zhou, Yicang; Tang, Sanyi

2010-05-03

99

Do dogs ( Canis familiaris ) show contagious yawning?  

Microsoft Academic Search

We report an experimental investigation into whether domesticated dogs display contagious yawning. Fifteen dogs were shown\\u000a video clips of (1) humans and (2) dogs displaying yawns and open-mouth expressions (not yawns) to investigate whether dogs\\u000a showed contagious yawning to either of these social stimuli. Only one dog performed significantly more yawns during or shortly\\u000a after viewing yawning videos than to

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

2009-01-01

100

Developmental and Comparative Perspectives of Contagious Yawning  

Microsoft Academic Search

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

Atsushi Senju

2010-01-01

101

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

NASA Astrophysics Data System (ADS)

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.

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

102

Disease awareness, information retrieval and change in biosecurity routines among pig farmers in association with the first PRRS outbreak in Sweden  

Microsoft Academic Search

Reaching farmers with information is important when eradicating outbreaks of contagious diseases, the actions they take related to contacts and biosecurity, as well as early notification of disease can have a significant effect on limiting the spread of disease. The aim of this study was to investigate Swedish pig farmers’ disease awareness, information retrieval and if they change their biosecurity

Maria Nöremark; Ann Lindberg; Ivar Vågsholm; Susanna Sternberg Lewerin

2009-01-01

103

Smittspridning Inom Rumsligt Avgraensade Populationer: En Modell foer Datorsimulering (Transmission of Contagious Diseases within Delimited Populations: A Model for Computer Simulation).  

National Technical Information Service (NTIS)

The report describes the structure and function of a model designed for simulation of the course of a disease within human populations. The model deals with epidemic courses after the introduction of pathogens which are transmissible from person to person...

G. Bostroem B. Einarsson M. Jansson

1985-01-01

104

Screening of banana bunchy top diseased plants: A way to control its spreading  

Microsoft Academic Search

Banana bunchy top disease (BBTD) is a nano-viral banana disease, which has been reducing both vegetative and reproductive growth of banana. It is spreading with the passage of time but minimize-able, if detected earlier through ELISA and PCR. For the concerned matter, an economic protocol for ELISA has been established for both time and chemicals. During this study, twenty BBTV

M. U. Dahot; Saifullah Khan; Naheed Kousar

105

Social networks and the spread of infectious diseases: The AIDS example  

Microsoft Academic Search

Conceptualizing a population as a set of individuals linked together to form a large social network provides a fruitful perspective for better understanding the spread of some infectious diseases. Data related to AIDS (the acquired immune deficiency syndrome) were used to illustrate the potential usefulness of a network approach in evaluating the infectious agent hypothesis when studying a disease or

Alden S. Klovdahl

1985-01-01

106

A model for assessing the effect of distance on disease spread in crop fields  

Microsoft Academic Search

Standard logistic regression is applied to model spatio-temporal plant disease spread in crop fields. The binary response variable observed at a given point in time is the disease status Y, taking on the value Y=1 for plants newly infected and Y=0 for healthy plants. The predictor variable used and tested here is the distance of a newly infected or healthy

Christoph Kleinn; Juan Jovel; Luko Hilje

1999-01-01

107

A branching model for the spread of infectious animal diseases in varying environments  

Microsoft Academic Search

This paper is concerned with a stochastic model, describing outbreaks of infectious diseases that have potentially great animal or human health consequences, and which can result in such severe economic losses that immediate sets of measures need to be taken to curb the spread. During an outbreak of such a disease, the environment that the infectious agent experiences is therefore

Pieter Trapman; Ronald Meester; Hans Heesterbeek

2004-01-01

108

Multiscale mobility networks and the spatial spreading of infectious diseases  

Microsoft Academic Search

Among the realistic ingredients to be considered in the computational modeling of infectious diseases, human mobility represents a crucial challenge both on the theoretical side and in view of the limited availability of empirical data. To study the interplay between short- scale commuting flows and long-range airline traffic in shaping the spatiotemporal pattern of a global epidemic we (i) analyze

Duygu Balcan; Hao Hud; Alessandro Vespignani

109

Evidence of spread of the emerging infectious disease, finch trichomonosis, by migrating birds.  

PubMed

Finch trichomonosis emerged in Great Britain in 2005 and led to epidemic mortality and a significant population decline of greenfinches, Carduelis chloris and chaffinches, Fringilla coelebs, in the central and western counties of England and Wales in the autumn of 2006. In this article, we show continued epidemic spread of the disease with a pronounced shift in geographical distribution towards eastern England in 2007. This was followed by international spread to southern Fennoscandia where cases were confirmed at multiple sites in the summer of 2008. Sequence data of the ITS1/5.8S/ITS2 ribosomal region and part of the small subunit (SSU) rRNA gene showed no variation between the British and Fennoscandian parasite strains of Trichomonas gallinae. Epidemiological and historical ring return data support bird migration as a plausible mechanism for the observed pattern of disease spread, and suggest the chaffinch as the most likely primary vector. This finding is novel since, although intuitive, confirmed disease spread by migratory birds is very rare and, when it has been recognised, this has generally been for diseases caused by viral pathogens. We believe this to be the first documented case of the spread of a protozoal emerging infectious disease by migrating birds. PMID:21935745

Lawson, Becki; Robinson, Robert A; Neimanis, Aleksija; Handeland, Kjell; Isomursu, Marja; Agren, Erik O; Hamnes, Inger S; Tyler, Kevin M; Chantrey, Julian; Hughes, Laura A; Pennycott, Tom W; Simpson, Vic R; John, Shinto K; Peck, Kirsi M; Toms, Mike P; Bennett, Malcolm; Kirkwood, James K; Cunningham, Andrew A

2011-09-21

110

Modelling the spread of hepatitis C via commercial tattoo parlours: implications for public health interventions  

Microsoft Academic Search

Hepatitis C (HCV) is a serious infection caused by a blood-borne virus. It is a contagious disease spreading via a variety\\u000a of transmission mechanisms including contaminated tattoo equipment. Effectively regulating commercial tattoo parlours can\\u000a greatly reduce this risk. This paper models the cost-effectiveness and optimal timing of such interventions, and parameterises\\u000a the model with data for Vienna, Austria. This dynamic

Doris A. Behrens; Marion S. Rauner; Jonathan P. Caulkins

2008-01-01

111

Multiscale mobility networks and the spatial spreading of infectious diseases  

PubMed Central

Among the realistic ingredients to be considered in the computational modeling of infectious diseases, human mobility represents a crucial challenge both on the theoretical side and in view of the limited availability of empirical data. To study the interplay between short-scale commuting flows and long-range airline traffic in shaping the spatiotemporal pattern of a global epidemic we (i) analyze mobility data from 29 countries around the world and find a gravity model able to provide a global description of commuting patterns up to 300 kms and (ii) integrate in a worldwide-structured metapopulation epidemic model a timescale-separation technique for evaluating the force of infection due to multiscale mobility processes in the disease dynamics. Commuting flows are found, on average, to be one order of magnitude larger than airline flows. However, their introduction into the worldwide model shows that the large-scale pattern of the simulated epidemic exhibits only small variations with respect to the baseline case where only airline traffic is considered. The presence of short-range mobility increases, however, the synchronization of subpopulations in close proximity and affects the epidemic behavior at the periphery of the airline transportation infrastructure. The present approach outlines the possibility for the definition of layered computational approaches where different modeling assumptions and granularities can be used consistently in a unifying multiscale framework.

Balcan, Duygu; Colizza, Vittoria; Goncalves, Bruno; Hu, Hao; Ramasco, Jose J.; Vespignani, Alessandro

2009-01-01

112

Link operations for slowing the spread of disease in complex networks  

NASA Astrophysics Data System (ADS)

A variety of social, biological and communication networks can be modelled using graph theoretical tools. Similar graphical tools can be used to model the topology by which disease, errors, and/or other undesired phenomenon etc. is spread and propagated through such networks. Certain network operations are proposed in this work that can be used to slow the spread of diseases in complex network topologies. The approach considered in this work differs from existing techniques in that it is based on optimally removing (or immunizing) individual links in the network as opposed to individual nodes. A systematic algorithm is outlined to achieve this edgewise immunization via a relaxed convex optimization protocol.

Bishop, A. N.; Shames, I.

2011-07-01

113

Generalized Markov Models of Infectious Disease Spread: A Novel Framework for Developing Dynamic Health Policies  

PubMed Central

We propose a class of mathematical models for the transmission of infectious diseases in large populations. This class of models, which generalizes the existing discrete-time Markov chain models of infectious diseases, is compatible with efficient dynamic optimization techniques to assist real-time selection and modification of public health interventions in response to evolving epidemiological situations and changing availability of information and medical resources. While retaining the strength of existing classes of mathematical models in their ability to represent the within-host natural history of disease and between-host transmission dynamics, the proposed models possess two advantages over previous models: (1) these models can be used to generate optimal dynamic health policies for controlling spreads of infectious diseases, and (2) these models are able to approximate the spread of the disease in relatively large populations with a limited state space size and computation time.

Yaesoubi, Reza; Cohen, Ted

2011-01-01

114

Do dogs (Canis familiaris) show contagious yawning?  

PubMed

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). PMID:19452178

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

2009-05-19

115

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

PubMed Central

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.

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

2013-01-01

116

Optimal control of age-structured population dynamics for spread of universally fatal diseases  

Microsoft Academic Search

This article is concerned with the optimal control problem of age-structured population dynamics for the spread of universally fatal diseases. The existence and uniqueness of solution of the system, which consists of a group of partial differential equations with nonlocal boundary conditions, is proved. The Dubovitskii and Milyutin functional analytical approach is adopted in the investigation of the Pontryagin maximum

Bing Sun; Mi-Xia Wu

2012-01-01

117

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

Microsoft Academic Search

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

D S Plorde

1981-01-01

118

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

Microsoft Academic Search

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 rela- tionships and potential causes for emergence of western North American salamander iridovirus strains, we sequenced

J. K. J ANCOVICH; E. W. D AVIDSON; N. PARAMESWARAN; J. MAO; V. G. C HINCHAR; J. P. C OLLINS; B. L. J ACOBS

2005-01-01

119

Modeling the spread of an infectious disease with bacteria and carriers in the environment  

Microsoft Academic Search

An SIS model with immigration for the spread of an infectious disease with bacteria and carriers in the environment is proposed and analyzed. It is assumed that susceptibles get infected directly by infectives as well as by their contacts with bacteria discharged by infectives in the environment. The growth rate of density of bacteria is assumed to be proportional to

J. B. Shukla; Vishal Singh; A. K. Misra

2011-01-01

120

Role of a Novel Antioncogene that Prevents Metastatic Spread of Disease.  

National Technical Information Service (NTIS)

The purpose of this grant is to determine a mechanism of action for a novel antioncogene (i.e. nm23) which prevents the metastatic spread of disease. Our data would indicate that there is no relationship of nm23 expression with proteolytic factors such as...

T. E. Kute

1996-01-01

121

Hitting Is Contagious: Experience and Action Induction  

ERIC Educational Resources Information Center

|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…

Gray, Rob; Beilock, Sian L.

2011-01-01

122

Contagious ecthyma in exotic sheep in Nigeria  

Microsoft Academic Search

From earlier and recent reports it would appear that contagious ecthyma is endemic in Nigeria although the virus was only recently isolated from indigenous breeds of sheep and goats from a natural outbreak (Obi and Gibbs, 1978). Many exotic breeds of sheep have been introduced into state farms for up-grading of indigenous breeds but a search through the literature revealed

A. E. J. Okoh

1980-01-01

123

Chronic Wasting Disease  

USGS Publications Warehouse

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.

Richards, Bryan

2007-01-01

124

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

125

A versatile ODE approximation to a network model for the spread of sexually transmitted diseases  

Microsoft Academic Search

.  ?We develop a moment closure approximation (MCA) to a network model of sexually transmitted disease (STD) spread through a\\u000a steady\\/casual partnership network. MCA has been used previously to approximate static, regular lattices, whereas application\\u000a to dynamic, irregular networks is a new endeavour, and application to sociologically-motivated network models has not been\\u000a attempted. Our goals are 1) to investigate issues relating

C. T. Bauch

2002-01-01

126

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...

127

Chronic contamination decreases disease spread: a Daphnia-fungus-copper case study  

PubMed Central

Chemical contamination and disease outbreaks have increased in many ecosystems. However, connecting pollution to disease spread remains difficult, in part, because contaminants can simultaneously exert direct and multi-generational effects on several host and parasite traits. To address these challenges, we parametrized a model using a zooplankton–fungus–copper system. In individual-level assays, we considered three sublethal contamination scenarios: no contamination, single-generation contamination (hosts and parasites exposed only during the assays) and multi-generational contamination (hosts and parasites exposed for several generations prior to and during the assays). Contamination boosted transmission by increasing contact of hosts with parasites. However, it diminished parasite reproduction by reducing the size and lifespan of infected hosts. Multi-generational contamination further reduced parasite reproduction. The parametrized model predicted that a single generation of contamination would enhance disease spread (via enhanced transmission), whereas multi-generational contamination would inhibit epidemics relative to unpolluted conditions (through greatly depressed parasite reproduction). In a population-level experiment, multi-generational contamination reduced the size of experimental epidemics but did not affect Daphnia populations without disease. This result highlights the importance of multi-generational effects for disease dynamics. Such integration of models with experiments can provide predictive power for disease problems in contaminated environments.

Civitello, David J.; Forys, Philip; Johnson, Adam P.; Hall, Spencer R.

2012-01-01

128

Modeling human mobility responses to the large-scale spreading of infectious diseases  

PubMed Central

Current modeling of infectious diseases allows for the study of realistic scenarios that include population heterogeneity, social structures, and mobility processes down to the individual level. The advances in the realism of epidemic description call for the explicit modeling of individual behavioral responses to the presence of disease within modeling frameworks. Here we formulate and analyze a metapopulation model that incorporates several scenarios of self-initiated behavioral changes into the mobility patterns of individuals. We find that prevalence-based travel limitations do not alter the epidemic invasion threshold. Strikingly, we observe in both synthetic and data-driven numerical simulations that when travelers decide to avoid locations with high levels of prevalence, this self-initiated behavioral change may enhance disease spreading. Our results point out that the real-time availability of information on the disease and the ensuing behavioral changes in the population may produce a negative impact on disease containment and mitigation.

Meloni, Sandro; Perra, Nicola; Arenas, Alex; Gomez, Sergio; Moreno, Yamir; Vespignani, Alessandro

2011-01-01

129

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

NASA Astrophysics Data System (ADS)

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.

Liu, Mao-Xing; Ruan, Jiong

2009-06-01

130

An investigation of auditory contagious yawning  

Microsoft Academic Search

Despite a widespread familiarity with the often compelling urge to yawn after perceiving someone else yawn, an understanding\\u000a of the neural mechanism underlying contagious yawning remains incomplete. In the present auditory fMRI study, listeners used\\u000a a 4-point scale to indicate how much they felt like yawning following the presentation of a yawn, breath, or scrambled yawn\\u000a sound. Not only were

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

2009-01-01

131

Geographical Information Systems: A Tool to Map and Analyze Disease Spread  

PubMed Central

Objective Use GIS to illustrate and understand the association between environmental factors and spread of infectious diseases. Introduction Spatial methods are an important component of epidemiological research motivated by a strong correlation between disease spread and ecological factors (1). Our case studies examine the relationship between environmental conditions, such as climate and location, and vector distribution and abundance. Therefore, GIS can be used as a platform for integrating local environmental and meteorological variables into the analysis of disease spread, which would help in surveillance and decision making. Methods Case study 1- Lyme disease -Lyme disease is a tickborne infection caused by the bacterium Borrelia burgdorferi. The goal of this study was to analyze the association between meteorological factors and Lyme disease risk in humans in Texas. A total of 1,212 cases reported from 138 counties in Texas from Jan 2000 to Dec 2010 were analyzed. We used temperature and precipitation raster grids to generate humidity maps for Texas region. Our results indicated that there is a strong positive association between Lyme disease incidence and humidity, with western cross timbers region having a higher risk then the low plains. Case study 2- Spinach – Motivated by the recent increase in food-borne outbreaks related to fresh produce, one of the objectives for this study was to use the geospatial analysis to elucidate factors that contribute to contamination of produce at preharvest. We collected 955 spinach samples from 13 produce farms in Colorado and Texas during 2010–2011 and tested the samples for Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella contamination. The spinach contamination results were then used in conjunction with the National Resource Information (NRI) databases along with the SSURGO database to predict environmental and meteorological factors contributing to spinach contamination. Our findings would help to reduce frequency of human foodborne illnesses related to fresh produce. Case study 3- Valley fever Coccidioidomycosis or Valley Fever (VF) is a fungal zoonosis affecting humans and a variety of animal species. In this study, we used Texas Veterinary Medical Diagnostic Laboratories (TVMDL) data of all dog sera tested for coccidioidomycosis from July 1999 - December 2009. Census data on human population density for Texas were used to determine the dog population density and identify disease clusters for the 5,871 submitted dog sera over a period of 10.5 years. Both the isopleth map of the VF seropositive rates in dogs across Texas and the identified spatial and spatio-temporal clusters of the disease suggested that VF occurs in the western and southwestern part of Texas at a much higher rate than in other areas of the state (2). Since VF is not a reportable disease in TX, dogs could be used as a sentinel for human infection. Results The above studies illustrate the utility of GIS as a tool in integrating different ecological factors to understand disease occurrence and spread. The geographical and temporal patterns found in these studies provide benchmark to support disease control activities in Texas. Additionally, the identification of high-risk areas may be useful for decision makers to improve and prevent future disease spread. Conclusions Spatial epidemiological research has challenges, such as dealing with coarse level and aspatial datasets. Testing laboratories provide limited spatial information up to the zip code level due to the confidentiality concerns. Spatial analysis of such dataset prevents research at finer resolutions (Census block or block group). Despite these limitations, spatial epidemiology continues to be an invaluable field in the research and surveillance of infectious disease.

Srinath, Indumathi; Szonyi, Barbara; Esteve-Gassent, Maria; Lupiani, Blanca; Gautam, Raju; Clavijo, Alfonso; Park, Sang-shin; Ivanek-Miojevic, Renata

2013-01-01

132

An investigation of auditory contagious yawning.  

PubMed

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. PMID:19679768

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

2009-09-01

133

Modelling the spread of foot-and-mouth disease in Australia.  

PubMed

Preparedness for an incursion of an exotic animal disease is of key importance to government, industry, producers and the Australian community. An important aspect of Australia's preparedness for a possible incursion of foot-and-mouth disease is investigation into the likely effectiveness and cost-efficiency of eradication strategies when applied to different regional outbreak scenarios. Disease modelling is a tool that can be used to study diseases such as foot-and-mouth disease to better understand potential disease spread and control under different conditions. The Australian Government Department of Agriculture, Fisheries and Forestry has been involved with epidemiologic simulation modelling for more than 10 years, and has developed a sophisticated spatial model for foot-and-mouth disease (AusSpread) that operates within a geographic information system framework. The model accommodates real farm boundary or point-location data, as well as synthesised data based on agricultural census and land use information. The model also allows for interactions between herds or flocks of different animal species and production type, and considers the role that such interactions are likely to play in the epidemiology of a regional outbreak of foot-and-mouth disease. The user can choose mitigations and eradication strategies from those that are currently described in Australia's veterinary emergency plan. The model also allows the user to evaluate the impact of constraints on the availability of resources for mitigations or eradication measures. Outputs include a range of maps and tabulated outbreak statistics describing the geographic extent of the outbreak and its duration, the numbers of affected, slaughtered, and, as relevant, vaccinated herds or flocks, and the cost of control and eradication. Cost-related outputs are based on budgets of the value of stock and the cost of mitigations, each of which can be varied by the user. These outputs are a valuable resource to assist with policy development and disease management. PMID:16395942

Garner, M G; Beckett, S D

2005-12-01

134

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

USGS Publications Warehouse

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.

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

2008-01-01

135

The spread of vaccine-preventable diseases by international travellers: a public-health concern.  

PubMed

Vaccine-preventable diseases (VPDs) are costly at both the individual and societal levels. The most common VPDs recorded in travellers are enteric (typhoid or paratyphoid B) fever, acute viral hepatitis, influenza, varicella, measles, pertussis and bacterial meningitis. Travellers suffering from VPDs are frequently hospitalized, illustrating the point that VPDs are serious and expensive. Many travellers are not properly immunized before travel. In addition to individual consequences, VPDs can have public-health consequences if they are introduced or re-introduced by infected travellers returning to areas with susceptible populations. The international spread of poliomyelitis, Neisseria meningitidis serogroup W135 meningococcal infections, measles and influenza provides strong evidence of the role of international travel in the globalization of VPDs. The surveillance of the emergence, re-emergence or spread of VPDs is essential to adapt pre-travel advice and the responses to the VPD. PMID:22862565

Gautret, P; Botelho-Nevers, E; Brouqui, P; Parola, P

2012-08-06

136

Identifying the relative priorities of subpopulations for containing infectious disease spread.  

PubMed

In response to the outbreak of an emerging infectious disease, e.g., H1N1 influenza, public health authorities will take timely and effective intervention measures to contain disease spread. However, due to the scarcity of required resources and the consequent social-economic impacts, interventions may be suggested to cover only certain subpopulations, e.g., immunizing vulnerable children and the elderly as well as closing schools or workplaces for social distancing. Here we are interested in addressing the question of how to identify the relative priorities of subpopulations for two measures of disease intervention, namely vaccination and contact reduction, especially when these measures are implemented together at the same time. We consider the measure of vaccination that immunizes susceptible individuals in different age subpopulations and the measure of contact reduction that cuts down individuals' effective contacts in different social settings, e.g., schools, households, workplaces, and general communities. In addition, we construct individuals' cross-age contact frequency matrix by inferring basic contact patterns respectively for different social settings from the socio-demographical census data. By doing so, we present a prioritization approach to identifying the target subpopulations that will lead to the greatest reduction in the number of disease transmissions. We calculate the relative priorities of subpopulations by considering the marginal effects of reducing the reproduction number for the cases of vaccine allocation by age and contact reduction by social setting. We examine the proposed approach by revisiting the real-world scenario of the 2009 Hong Kong H1N1 influenza epidemic and determine the relative priorities of subpopulations for age-specific vaccination and setting-specific contact reduction. We simulate the influenza-like disease spread under different settings of intervention. The results have shown that the proposed approach can improve the effectiveness of disease control by containing disease transmissions in a host population. PMID:23776461

Xia, Shang; Liu, Jiming; Cheung, William

2013-06-12

137

Identifying the Relative Priorities of Subpopulations for Containing Infectious Disease Spread  

PubMed Central

In response to the outbreak of an emerging infectious disease, e.g., H1N1 influenza, public health authorities will take timely and effective intervention measures to contain disease spread. However, due to the scarcity of required resources and the consequent social-economic impacts, interventions may be suggested to cover only certain subpopulations, e.g., immunizing vulnerable children and the elderly as well as closing schools or workplaces for social distancing. Here we are interested in addressing the question of how to identify the relative priorities of subpopulations for two measures of disease intervention, namely vaccination and contact reduction, especially when these measures are implemented together at the same time. We consider the measure of vaccination that immunizes susceptible individuals in different age subpopulations and the measure of contact reduction that cuts down individuals’ effective contacts in different social settings, e.g., schools, households, workplaces, and general communities. In addition, we construct individuals’ cross-age contact frequency matrix by inferring basic contact patterns respectively for different social settings from the socio-demographical census data. By doing so, we present a prioritization approach to identifying the target subpopulations that will lead to the greatest reduction in the number of disease transmissions. We calculate the relative priorities of subpopulations by considering the marginal effects of reducing the reproduction number for the cases of vaccine allocation by age and contact reduction by social setting. We examine the proposed approach by revisiting the real-world scenario of the 2009 Hong Kong H1N1 influenza epidemic and determine the relative priorities of subpopulations for age-specific vaccination and setting-specific contact reduction. We simulate the influenza-like disease spread under different settings of intervention. The results have shown that the proposed approach can improve the effectiveness of disease control by containing disease transmissions in a host population.

Xia, Shang; Liu, Jiming; Cheung, William

2013-01-01

138

The arrival, establishment and spread of exotic diseases: patterns and predictions.  

PubMed

The impact of human activities on the principles and processes governing the arrival, establishment and spread of exotic pathogens is illustrated by vector-borne diseases such as malaria, dengue, chikungunya, West Nile, bluetongue and Crimean-Congo haemorrhagic fevers. Competent vectors, which are commonly already present in the areas, provide opportunities for infection by exotic pathogens that are introduced by travel and trade. At the same time, the correct combination of environmental conditions (both abiotic and biotic) makes many far-flung parts of the world latently and predictably, but differentially, permissive to persistent transmission cycles. Socioeconomic factors and nutritional status determine human exposure to disease and resistance to infection, respectively, so that disease incidence can vary independently of biological cycles. PMID:20372156

Randolph, Sarah E; Rogers, David J

2010-04-07

139

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

140

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

PubMed Central

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

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

2012-01-01

141

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

SciTech Connect

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.

Pullum, Laura L [ORNL; Cui, Xiaohui [New York Institute of Technology (NYIT)

2012-01-01

142

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

NASA Astrophysics Data System (ADS)

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.

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

143

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

PubMed

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. PMID:15643965

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

2005-01-01

144

Effects of delayed recovery and nonuniform transmission on the spreading of diseases in complex networks  

NASA Astrophysics Data System (ADS)

We investigate the effects of delaying the time to recovery (delayed recovery) and of nonuniform transmission on the propagation of diseases on structured populations. Through a mean-field approximation and large-scale numerical simulations, we find that postponing the transition from the infectious to the recovered states can largely reduce the epidemic threshold, therefore promoting the outbreak of epidemics. On the other hand, if we consider nonuniform transmission among individuals, the epidemic threshold increases, thus inhibiting the spreading process. When both mechanisms are at work, the latter might prevail, hence resulting in an increase of the epidemic threshold with respect to the standard case, in which both ingredients are absent. Our findings are of interest for a better understanding of how diseases propagate on structured populations and to a further design of efficient immunization strategies.

Xia, Cheng-yi; Wang, Zhen; Sanz, Joaquin; Meloni, Sandro; Moreno, Yamir

2013-04-01

145

Computer animations stimulate contagious yawning in chimpanzees  

PubMed Central

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.

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

2009-01-01

146

Computer animations stimulate contagious yawning in chimpanzees.  

PubMed

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. PMID:19740888

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

2009-09-09

147

INFECTION WITH FOOT-AND-MOUTH DISEASE VIRUS CAUSES LOSS OF CIRCULATING PLASMACYTOID DENDRITIC CELLS AND ABROGATES THE INTERFERON ALPHA RESPONSE TO TLR AGONISTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Immune evasion by pathogens is often critical to virulence and spread of the infectious agent. Foot-and-mouth disease virus (FMDV) is considered one of the most contagious infections known yet is very sensitive to both type I and type II interferons (IFN). In many species including swine, plasmacyto...

148

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

PubMed Central

Sexually transmitted pathogens persist in populations despite the availability of biomedical interven tions 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 the 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 behaviors 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 infectiousness is short, infection is more concentrated in high-activity, high-concurrency individuals even when all other factors are held constant. Widespread screening programs would be enhanced by follow-up interventions targeting higher-risk individuals, because screening shortens the expected duration of infectiousness and causes a greater relative decrease in prevalence among lower-activity than in higher-activity individuals. Even for pathogens with longer durations of infectiousness our findings suggest that targeting vaccination and behavioural interventions towards high-activity individuals provides comparable benefits to population-wide interventions.

Robinson, Katy; Cohen, Ted; Colijn, Caroline

2012-01-01

149

Spread of neuronal degeneration in a dopaminergic, Lrrk-G2019S model of Parkinson disease.  

PubMed

Flies expressing the most common Parkinson disease (PD)-related mutation, LRRK2-G2019S, in their dopaminergic neurons show loss of visual function and degeneration of the retina, including mitochondrial abnormalities, apoptosis and autophagy. Since the photoreceptors that degenerate are not dopaminergic, this demonstrates nonautonomous degeneration, and a spread of pathology. This provides a model consistent with Braak's hypothesis on progressive PD. The loss of visual function is specific for the G2019S mutation, implying the cause is its increased kinase activity, and is enhanced by increased neuronal activity. These data suggest novel explanations for the variability in animal models of PD. The specificity of visual loss to G2019S, coupled with the differences in neural firing rate, provide an explanation for the variability between people with PD in visual tests. PMID:23529190

Hindle, Samantha J; Elliott, Christopher J H

2013-03-25

150

A comprehensive review of the retroperitoneal anatomy, neoplasms, and pattern of disease spread.  

PubMed

A clear understanding of the normal anatomy and pattern of disease spread is important in evaluating many retroperitoneal disorders. Primary retroperitoneal tumors are uncommon, accounting for 0.1%-0.2% of all malignancies in the body; 80%-90% of all primary retroperitoneal tumors are malignant. The primary retroperitoneal neoplasms can be divided into solid or cystic masses. The solid neoplasms can be classified according to their tissue of origin into 3 main categories: mesodermal tumors, neurogenic tumors, and extragonadal germ cell tumors. Computed tomography and magnetic resonance imaging play a vital role in the localization, characterization, evaluation of the extent of local invasion, assessment of metastases, and determination of treatment response for these tumors. The diagnosis of a primary retroperitoneal malignancy is often challenging owing to overlap of imaging findings. A definitive diagnosis can be established only at histopathologic analysis. However, knowledge of the important tumor characteristics, growth pattern, and vascularity can assist in narrowing the differential diagnosis. PMID:24070713

Osman, Sherif; Lehnert, Bruce E; Elojeimy, Saeed; Cruite, Irene; Mannelli, Lorenzo; Bhargava, Puneet; Moshiri, Mariam

151

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

PubMed

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. PMID:20500006

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

2009-01-01

152

Spread of neuronal degeneration in a dopaminergic, Lrrk-G2019S model of Parkinson disease  

PubMed Central

Flies expressing the most common Parkinson disease (PD)-related mutation, LRRK2-G2019S, in their dopaminergic neurons show loss of visual function and degeneration of the retina, including mitochondrial abnormalities, apoptosis and autophagy. Since the photoreceptors that degenerate are not dopaminergic, this demonstrates nonautonomous degeneration, and a spread of pathology. This provides a model consistent with Braak’s hypothesis on progressive PD. The loss of visual function is specific for the G2019S mutation, implying the cause is its increased kinase activity, and is enhanced by increased neuronal activity. These data suggest novel explanations for the variability in animal models of PD. The specificity of visual loss to G2019S, coupled with the differences in neural firing rate, provide an explanation for the variability between people with PD in visual tests.

Hindle, Samantha J.; Elliott, Christopher J.H.

2013-01-01

153

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

USGS Publications Warehouse

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

Henaux, V.; Samuel, M. D.

2011-01-01

154

Impact of regulatory perturbations to disease spread through cattle movements in Great Britain  

PubMed Central

During the past decade the British livestock industry has suffered from several major pathogen outbreaks, and a variety of regulatory and disease control measures have been applied to the movement of livestock with the express aim of mitigating the spread of infection. The Rapid Analysis and Detection of Animal-related Risks (RADAR) project, which has been collecting data on the movement of cattle since 1998, provides a relatively comprehensive record of how these policies have influenced the movement of cattle between animal holdings, markets, and slaughterhouses in Britain. Many previous studies have focused on the properties of the network that can be derived from these movements – treating farms as nodes and movements as directed (and potentially weighted) edges in the network. However, of far greater importance is how these policy changes have influenced the potential spread of infectious diseases. Here we use a stochastic fully individual-based model of cattle in Britain to assess how the epidemic potential has varied from 2000 to 2009 as the pattern of movements has changed in response to legislation and market forces. Our simulations show that the majority of policy changes lead to significant decreases in the epidemic potential (measured in multiple ways), but that this potential then increases through time as cattle farmers modify their behaviour in response. Our results suggest that the cattle industry is likely to experience boom-bust dynamics, with the actions that farmers take during epidemic-free periods to maximise their profitability likely to increase the potential for large-scale epidemics to occur.

Vernon, Matthew C.; Keeling, Matt J.

2012-01-01

155

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

PubMed

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. PMID:21361408

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

2011-01-01

156

Quantifying the Risk of Localised Animal Movement Bans for Foot-and-Mouth Disease  

Microsoft Academic Search

The maintenance of disease-free status from Foot-and-Mouth Disease is of significant socio-economic importance to countries such as the UK. The imposition of bans on the movement of susceptible livestock following the discovery of an outbreak is deemed necessary to prevent the spread of what is a highly contagious disease, but has a significant economic impact on the agricultural community in

David Schley; Simon Gubbins; David J. Paton; Michael B. Gravenor

2009-01-01

157

Disease spread across multiple scales in a spatial hierarchy: effect of host spatial structure and of inoculum quantity and distribution.  

PubMed

Spatial patterns of both the host and the disease influence disease spread and crop losses. Therefore, the manipulation of these patterns might help improve control strategies. Considering disease spread across multiple scales in a spatial hierarchy allows one to capture important features of epidemics developing in space without using explicitly spatialized variables. Thus, if the system under study is composed of roots, plants, and planting hills, the effect of host spatial pattern can be studied by varying the number of plants per planting hill. A simulation model based on hierarchy theory was used to simulate the effects of large versus small planting hills, low versus high level of initial infections, and aggregated versus uniform distribution of initial infections. The results showed that aggregating the initially infected plants always resulted in slower epidemics than spreading out the initial infections uniformly. Simulation results also showed that, in most cases, disease epidemics were slower in the case of large host aggregates (100 plants/hill) than with smaller aggregates (25 plants/hill), except when the initially infected plants were both numerous and spread out uniformly. The optimal strategy for disease control depends on several factors, including initial conditions. More importantly, the model offers a framework to account for the interplay between the spatial characteristics of the system, rates of infection, and aggregation of the disease. PMID:19522581

Gosme, Marie; Lucas, Philippe

2009-07-01

158

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

PubMed

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 epizootiologic models of disease risks. PMID:21719821

Hénaux, Viviane; Samuel, Michael D

2011-07-01

159

Modelling bovine babesiosis: a tool to simulate scenarios for pathogen spread and to test control measures for the disease.  

PubMed

Tick-borne diseases are of increasing concern in many countries, particularly as a consequence of changes in land use and climate. Ticks are vectors of numerous pathogens (viruses, bacteria, protozoa) that can be harmful to humans and animals. In the context of animal health, bovine babesiosis poses a recurrent threat to cattle herds. In this study, we use a modeling approach to investigate the spread of babesiosis and evaluate control measures. A previously developed tick population dynamics model (here, Ixodes ricinus) is coupled with a pathogen spread model (here, the protozoan Babesia divergens), which describes pathogen spread in a dairy herd through the following processes: transmission, acquisition, transovarial transmission, transstadial persistence, and clearance of the pathogen. An assessment of the simulated B. divergens prevalence levels in ticks and cattle in the context of existing knowledge and data suggested that the model provides a realistic representation of pathogen spread. The model was then used to evaluate the influence of host density and the effect of acaricides on B. divergens prevalence in cattle. Increasing deer density results in an increase in prevalence in cattle whereas increasing cattle stocking rate results in a slight decrease. A potential increase in deer density would thus have an amplification effect on disease spread due to the increase in the number of infected ticks. Regular use of acaricides produces a reduction in pathogen prevalence in cattle. This model could be adapted to other tick-borne diseases. PMID:22341037

Hoch, Thierry; Goebel, Julien; Agoulon, Albert; Malandrin, Laurence

2012-02-16

160

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...

161

Connectivity of the American Agricultural Landscape: Assessing the National Risk of Crop Pest and Disease Spread  

NSDL National Science Digital Library

More than two-thirds of cropland in the United States is devoted to the production of just four crop speciesâÂÂmaize, wheat, soybeans, and cottonâÂÂraising concerns that homogenization of the American agricultural landscape could facilitate widespread disease and pest outbreaks, compromising the national food supply. As a new component in national agricultural risk assessment, we employed a graph-theoretic approach to examine the connectivity of these crops across the United States. We used county crop acreage to evaluate the landscape resistance to transmissionâÂÂthe degree to which host availability limits spread in any given regionâÂÂfor pests or pathogens dependent on each crop. For organisms that can disperse under conditions of lower host availability, maize and soybean are highly connected at a national scale, compared with the more discrete regions of wheat and cotton production. Determining the scales at which connectivity becomes disrupted for organisms with different dispersal abilities may help target rapid-response regions and the development of strategic policies to enhance agricultural landscape heterogeneity.

Karen Garrett (Kansas State University;Department of Plant Pathology)

2009-02-01

162

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

NASA Astrophysics Data System (ADS)

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

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

2008-11-01

163

A prototype forecasting system for bird-borne disease spread in North America based on migratory bird movements.  

PubMed

The past two decades have seen major outbreaks of influenza viruses and flaviviruses that are spread at least in part by migratory birds. Although much new information has accumulated on the natural history of the viruses, and on the geography of migration by individual bird species, no synthesis has been achieved regarding likely patterns of spread of such pathogens by migratory birds, which constitutes a large-scale challenge in understanding the geography of bird migration. We here present a first step in this direction: a summary of seasonal (breeding, wintering) distributions of all 392 North American bird species that show marked seasonal migratory movements and that meet a series of conditions for inclusion in our analyses. We use species-level interseasonal connectivity among distributional areas to make initial forecasts of patterns of spread of bird-borne diseases via bird migration. We identify key next steps towards improved forecasting of spread patterns of bird-borne pathogens in North America, which will require substantial improvements in knowledge of the geography of bird migration. PMID:21352770

Peterson, A Townsend; Andersen, Michael J; Bodbyl-Roels, Sarah; Hosner, Pete; Nyári, Arpád; Oliveros, Carl; Pape?, Monica

2009-11-26

164

Absence of contagious yawning in children with autism spectrum disorder.  

PubMed

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. PMID:17698452

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

2007-12-22

165

Spread of porcine circovirus associated disease (PCVAD) in Ontario (Canada) swine herds: Part I. Exploratory spatial analysis  

PubMed Central

Background The systemic form of porcine circovirus associated disease (PCVAD), also known as postweaning multisystemic wasting syndrome (PMWS) was initially detected in the early 1990s. Starting in 2004, the Canadian swine industry experienced considerable losses due to PCVAD, concurrent with a shift in genotype of porcine circovirus type 2 (PCV2). Objectives of the current study were to explore spatial characteristics of self-reported PCVAD distribution in Ontario between 2004 and 2008, and to investigate the existence and nature of local spread. Results The study included 278 swine herds from a large disease-monitoring project that included porcine reproductive and respiratory syndrome (PRRS) virus-positive herds identified by the diagnostic laboratory, and PRRS virus-negative herds directly from the target population. Herds were included if they had growing pigs present on-site and available geographical coordinates for the sampling site. Furthermore, herds were defined as PCVAD-positive if a producer reported an outbreak of circovirus associated disease, or as PCVAD-negative if no outbreak was noted. Spatial trend was investigated using generalized additive models and time to PCVAD outbreak in a herd using Cox's proportional hazard model; spatial and spatio-temporal clustering was explored using K-functions; and location of most likely spatial and spatio-temporal clusters was investigated using scan statistics. Over the study period, the risk of reporting a PCVAD-positive herd tended to be higher in the eastern part of the province after adjustment for herd PRRS status (P = 0.05). This was partly confirmed for spread (Partial P < 0.01). Local spread also appeared to exist, as suggested by the tentative (P = 0.06) existence of spatio-temporal clustering of PCVAD and detection of a spatio-temporal cluster (P = 0.04). Conclusions In Ontario, PCVAD has shown a general trend, spreading from east-to-west. We interpret the existence of spatio-temporal clustering as evidence of spatio-temporal aggregation of PCVAD-positive cases above expectations and, together with the existence of spatio-temporal and spatial clusters, as suggestive of apparent local spread of PCVAD. Clustering was detected at small spatial and temporal scales. Other patterns of spread could not be detected; however, survival rates in discrete Ontario zones, as well as a lack of a clear spatial pattern in the most likely spatio-temporal clusters, suggest other between-herd transmission mechanisms.

2010-01-01

166

Measures of concurrency in networks and the spread of infectious disease  

Microsoft Academic Search

An investigation is made into the impact of concurrent partnerships on epidemic spread. Starting from a definition of concurrency on the level of individuals, the authors define ways to quantify concurrency on the population level. An index of concurrency based on graph theoretical considerations is introduced, and the way in which it is related to the degree distribution of the

Martina Morris

1996-01-01

167

Lognormal infection times of online information spread.  

PubMed

The infection times of individuals in online information spread such as the inter-arrival time of Twitter messages or the propagation time of news stories on a social media site can be explained through a convolution of lognormally distributed observation and reaction times of the individual participants. Experimental measurements support the lognormal shape of the individual contributing processes, and have resemblance to previously reported lognormal distributions of human behavior and contagious processes. PMID:23700473

Doerr, Christian; Blenn, Norbert; Van Mieghem, Piet

2013-05-21

168

Social Network Sensors for Early Detection of Contagious Outbreaks  

Microsoft Academic Search

Current methods for the detection of contagious outbreaks give contemporaneous information about the course of an epidemic at best. Individuals at the center of a social network are likely to be infected sooner, on average, than those at the periphery. However, mapping a whole network to identify central individuals whom to monitor is typically very difficult. We propose an alternative

Nicholas A. Christakis; James H. Fowler; Olaf Sporns

2010-01-01

169

Absence of contagious yawning in children with autism spectrum disorder  

Microsoft Academic Search

Summary 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

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

2007-01-01

170

Yearning to yawn: the neural basis of contagious yawning  

Microsoft Academic Search

Yawning is contagious: Watching another person yawn may trigger us to do the same. Here we studied brain activation with functional magnetic resonance imaging (fMRI) while subjects watched videotaped yawns. Significant increases in the blood oxygen level dependent (BOLD) signal, specific to yawn viewing as contrasted to viewing non-nameable mouth movements, were observed in the right posterior superior temporal sulcus

Martin Schürmann; Maike D. Hesse; Klaas E. Stephan; Miiamaaria Saarela; Karl Zilles; Riitta Hari; Gereon R. Fink

2005-01-01

171

Methodological Problems in the Study of Contagious Yawning  

Microsoft Academic Search

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

Matthew W. Campbell; Frans B. M. de Waal

2010-01-01

172

Yawn, Yawn, Yawn, Yawn; Yawn, Yawn, Yawn! The Social, Evolutionary and Neuroscientific Facets of Contagious Yawning  

Microsoft Academic Search

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

Steven M. Platek

2010-01-01

173

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

ERIC Educational Resources Information Center

|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…

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

2009-01-01

174

Contagious yawning: the role of self-awareness and mental state attribution  

Microsoft Academic Search

Contagious yawning is a common, but poorly understood phenomenon. We hypothesized that contagious yawning is part of a more general phenomenon known as mental state attribution (i.e. the ability to inferentially model the mental states of others). To test this hypothesis we compared susceptibility to contagiously yawn with performance on a self-face recognition task, several theory of mind stories, and

Steven M Platek; Samuel R Critton; Thomas E Myers; Gordon G Gallup

2003-01-01

175

Modeling the spread and control of foot-and-mouth disease in Pennsylvania following its discovery and options for control  

PubMed Central

In this paper, we simulate outbreaks of foot-and-mouth disease in the Commonwealth of Pennsylvania, USA – after the introduction of a state-wide movement ban – as they might unfold in the presence of mitigation strategies. We have adapted a model previously used to investigate FMD control policies in the UK to examine the potential for disease spread given an infection seeded in each county in Pennsylvania. The results are highly dependent upon the county of introduction and the spatial scale of transmission. Should the transmission kernel be identical to that for the UK, the epidemic impact is limited to fewer than 20 premises, regardless of the county of introduction. However, for wider kernels where infection can spread further, outbreaks seeded in or near the county with highest density of premises and animals result in large epidemics (>150 premises). Ring culling and vaccination reduce epidemic size, with the optimal radius of the rings being dependent upon the county of introduction. Should the kernel width exceed a given county-dependent threshold, ring culling is unable to control the epidemic. We find that a vaccinate-to-live policy is generally preferred to ring culling (in terms of reducing the overall number of premises culled), indicating that well-targeted control can dramatically reduce the risk of large scale outbreaks of foot-and-mouth disease occurring in Pennsylvania.

Tildesley, Michael J.; Smith, Gary; Keeling, Matt J.

2013-01-01

176

What's the Difference Between Infectious and Contagious?  

MedlinePLUS

... April 2011 * Names have been changed to protect user privacy. For Teens For Kids For Parents MORE ON THIS TOPIC About Birth Control: What You Need to Know About Sexually Transmitted Diseases (STDs) Hand ...

177

Transporting Patients with Lethal Contagious Infections.  

National Technical Information Service (NTIS)

The Aeromedical Isolation Team (AIT) is maintained undet the command of COL Edward M. Eitzen, Jr., at the United States Army Medical Institute of Infectious Diseases (USAMRIID), located at Fort Detrick, Maryland. The AIT is a unique military medical team ...

C. Swartz

2002-01-01

178

Discrete-time Markov chain approach to contact-based disease spreading in complex networks  

NASA Astrophysics Data System (ADS)

Many epidemic processes in networks spread by stochastic contacts among their connected vertices. There are two limiting cases widely analyzed in the physics literature, the so-called contact process (CP) where the contagion is expanded at a certain rate from an infected vertex to one neighbor at a time, and the reactive process (RP) in which an infected individual effectively contacts all its neighbors to expand the epidemics. However, a more realistic scenario is obtained from the interpolation between these two cases, considering a certain number of stochastic contacts per unit time. Here we propose a discrete-time formulation of the problem of contact-based epidemic spreading. We resolve a family of models, parameterized by the number of stochastic contact trials per unit time, that range from the CP to the RP. In contrast to the common heterogeneous mean-field approach, we focus on the probability of infection of individual nodes. Using this formulation, we can construct the whole phase diagram of the different infection models and determine their critical properties.

Gómez, S.; Arenas, A.; Borge-Holthoefer, J.; Meloni, S.; Moreno, Y.

2010-02-01

179

Model hierarchies in edge-based compartmental modeling for infectious disease spread.  

PubMed

We consider the family of edge-based compartmental models for epidemic spread developed in Miller et al. (J R Soc Interface 9(70):890-906, 2012). These models allow for a range of complex behaviors, and in particular allow us to explicitly incorporate duration of a contact into our mathematical models. Our focus here is to identify conditions under which simpler models may be substituted for more detailed models, and in so doing we define a hierarchy of epidemic models. In particular we provide conditions under which it is appropriate to use the standard mass action SIR model, and we show what happens when these conditions fail. Using our hierarchy, we provide a procedure leading to the choice of the appropriate model for a given population. Our result about the convergence of models to the mass action model gives clear, rigorous conditions under which the mass action model is accurate. PMID:22911242

Miller, Joel C; Volz, Erik M

2012-08-22

180

Spread of citrus huanglongbing (greening disease) following incursion into Papua New Guinea  

Microsoft Academic Search

Huanglongbing (HLB) was previously known in many countries as greening disease. It is caused by the bacterium ‘Candidates Liberibacter asiaticus’ and is vectored by the Asian citrus psyllid Diaphorina citri (Hemiptera: Psyllidae). A delimiting survey showed that the disease had become established in, and near the border town of,\\u000a Vanimo in the Sandaun Province of Papua New Guinea (PNG) by

R. I. Davis; T. G. Gunua; M. F. Kame; D. Tenakanai; T. K. Ruabete

2005-01-01

181

Subclinical infection and asymptomatic carriage of gastrointestinal zoonoses: occupational exposure, environmental pathways, and the anonymous spread of disease.  

PubMed

Asymptomatic carriage of gastrointestinal zoonoses is more common in people whose profession involves them working directly with domesticated animals. Subclinical infections (defined as an infection in which symptoms are either asymptomatic or sufficiently mild to escape diagnosis) are important within a community as unknowing (asymptomatic) carriers of pathogens do not change their behaviour to prevent the spread of disease; therefore the public health significance of asymptomatic human excretion of zoonoses should not be underestimated. However, optimal strategies for managing diseases where asymptomatic carriage instigates further infection remain unresolved, and the impact on disease management is unclear. In this review we consider the environmental pathways associated with prolonged antigenic exposure and critically assess the significance of asymptomatic carriage in disease outbreaks. Although screening high-risk groups for occupationally acquired diseases would be logistically problematical, there may be an economic case for identifying and treating asymptomatic carriage if the costs of screening and treatment are less than the costs of identifying and treating those individuals infected by asymptomatic hosts. PMID:23659675

Quilliam, R S; Cross, P; Williams, A Prysor; Edwards-Jones, G; Salmon, R L; Rigby, D; Chalmers, R M; Thomas, D Rh; Jones, D L

2013-05-10

182

Methodological problems in the study of contagious yawning.  

PubMed

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. PMID:20357470

Campbell, Matthew W; de Waal, Frans B M

2010-03-26

183

Presence of contagious yawning in children with autism spectrum disorder.  

PubMed

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

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

2013-07-22

184

Spread of ticks and tick-borne diseases in Germany due to global warming  

Microsoft Academic Search

Tick-transmitted diseases like tick-borne encephalitis and Lyme Borreliosis have been well known in Germany for decades. Global\\u000a climate changes may influence the emergence and reemergence of diseases. Ongoing research now gives an additional focus on\\u000a other tick-borne pathogens such as Coxiella burnetii, Rickettsia conorii, Anaplasma phagocytophilum and Babesia spp., the causative agents of Q-fever, Mediterranean spotted fever, Anaplasmosis and Babesiosis,

Kathrin Hartelt; Silvia Pluta; Rainer Oehme; Peter Kimmig

2008-01-01

185

Yearning to yawn: the neural basis of contagious yawning.  

PubMed

Yawning is contagious: Watching another person yawn may trigger us to do the same. Here we studied brain activation with functional magnetic resonance imaging (fMRI) while subjects watched videotaped yawns. Significant increases in the blood oxygen level dependent (BOLD) signal, specific to yawn viewing as contrasted to viewing non-nameable mouth movements, were observed in the right posterior superior temporal sulcus (STS) and bilaterally in the anterior STS, in agreement with the high affinity of STS to social cues. However, no additional yawn-specific activation was observed in Broca's area, the core region of the human mirror-neuron system (MNS) that matches action observation and execution. Thus, activation associated with viewing another person yawn seems to circumvent the essential parts of the MNS, in line with the nature of contagious yawns as automatically released behavioural acts-rather than truly imitated motor patterns that would require detailed action understanding. The subjects' self-reported tendency to yawn covaried negatively with activation of the left periamygdalar region, suggesting a connection between yawn contagiousness and amygdalar activation. PMID:15670705

Schürmann, Martin; Hesse, Maike D; Stephan, Klaas E; Saarela, Miiamaaria; Zilles, Karl; Hari, Riitta; Fink, Gereon R

2005-02-15

186

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

NASA Astrophysics Data System (ADS)

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

Thomas, Stephanie Margarete; Beierkuhnlein, Carl

2013-05-01

187

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

PubMed

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

Thomas, Stephanie Margarete; Beierkuhnlein, Carl

2013-03-27

188

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

National Technical Information Service (NTIS)

A study conducted by Carpenter, O Brien, Hagerman and McCarl in 2011 estimates the economic impact of a foot and mouth disease (FMD) epidemic in the United States to be $2.3 $69.0 billion. We simulate an outbreak of FMD across central California using the...

D. Alok

2013-01-01

189

Personalized ventilation as a control measure for airborne transmissible disease spread  

PubMed Central

The protective role of personalized ventilation (PV) against plausible airborne transmissible disease was investigated using cough droplets released from a ‘coughing machine’ simulating the human cough at different distances (1, 1.75 and 3 m) from the PV user. Particle image velocimetry was used to characterize and visualize the interaction between the cough-generated multiphase flow and PV-induced flow in the inhalation zone of the thermal breathing manikin. A dose–response model for unsteady imperfectly mixed environment was used to estimate the reduction in infection risk of two common diseases that can be transmitted by airborne mode. PV was able to both reduce the peak aerosol concentration levels and shorten the exposure time at all the examined injection distances. PV could reduce the infection risks of two diseases, influenza A and tuberculosis, by between 27 and 65 per cent. The protection offered by PV is less effective at a distance of 1.75 m than the other distances, as shown in the risk assessment results, as the PV-generated flow was blown off by the cough-generated flow for the longest time. Results of this study demonstrate the ability of desktop PV to mitigate the infection risk of airborne transmissible disease.

Pantelic, Jovan; Sze-To, Gin Nam; Tham, Kwok Wai; Chao, Christopher Y. H.; Khoo, Yong Chuan Mike

2009-01-01

190

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

PubMed

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

Michel, Anita L; Bengis, Roy G

2012-06-20

191

Indirect Genetic Effects and the Spread of Infectious Disease: Are We Capturing the Full Heritable Variation Underlying Disease Prevalence?  

Microsoft Academic Search

Reducing disease prevalence through selection for host resistance offers a desirable alternative to chemical treatment. Selection for host resistance has proven difficult, however, due to low heritability estimates. These low estimates may be caused by a failure to capture all the relevant genetic variance in disease resistance, as genetic analysis currently is not taylored to estimate genetic variation in infectivity.

Debby Lipschutz-Powell; John A. Woolliams; Piter Bijma; Andrea B. Doeschl-Wilson

2012-01-01

192

Valuing flexibility in the control of contagious animal disease  

Microsoft Academic Search

Animal epidemics can bring severe damage to the livestock sector as well as the whole society. In controlling animal epidemic, the selection of suboptimal control strategies may lead to unnecessary costs which should be avoided. This paper argues that uncertainties about the state of the epidemic, irreversible actions like culling and vaccination of animals, and the possibility of learning during

Lan Ge; Monique Mourits; Ruud Huirne

2005-01-01

193

Intracerebral Borna Disease Virus Infection of Bank Voles Leading to Peripheral Spread and Reverse Transcription of Viral RNA  

PubMed Central

Bornaviruses, which chronically infect many species, can cause severe neurological diseases in some animal species; their association with human neuropsychiatric disorders is, however, debatable. The epidemiology of Borna disease virus (BDV), as for other members of the family Bornaviridae, is largely unknown, although evidence exists for a reservoir in small mammals, for example bank voles (Myodes glareolus). In addition to the current exogenous infections and despite the fact that bornaviruses have an RNA genome, bornavirus sequences integrated into the genomes of several vertebrates millions of years ago. Our hypothesis is that the bank vole, a common wild rodent species in traditional BDV-endemic areas, can serve as a viral host; we therefore explored whether this species can be infected with BDV, and if so, how the virus spreads and whether viral RNA is transcribed into DNA in vivo. We infected neonate bank voles intracerebrally with BDV and euthanized them 2 to 8 weeks post-infection. Specific Ig antibodies were detectable in 41%. Histological evaluation revealed no significant pathological alterations, but BDV RNA and antigen were detectable in all infected brains. Immunohistology demonstrated centrifugal spread throughout the nervous tissue, because viral antigen was widespread in peripheral nerves and ganglia, including the mediastinum, esophagus, and urinary bladder. This was associated with viral shedding in feces, of which 54% were BDV RNA-positive, and urine at 17%. BDV nucleocapsid gene DNA occurred in 66% of the infected voles, and, surprisingly, occasionally also phosphoprotein DNA. Thus, intracerebral BDV infection of bank vole led to systemic infection of the nervous tissue and viral excretion, as well as frequent reverse transcription of the BDV genome, enabling genomic integration. This first experimental bornavirus infection in wild mammals confirms the recent findings regarding bornavirus DNA, and suggests that bank voles are capable of bornavirus transmission.

Kinnunen, Paula Maria; Inkeroinen, Hanna; Ilander, Mette; Kallio, Eva Riikka; Heikkila, Henna Pauliina; Koskela, Esa; Mappes, Tapio; Palva, Airi; Vaheri, Antti; Kipar, Anja; Vapalahti, Olli

2011-01-01

194

Neurologic Disease Induced by Polytropic Murine Retroviruses: Neurovirulence Determined by Efficiency of Spread to Microglial Cells  

Microsoft Academic Search

Several murine leukemia viruses (MuLV) induce neurologic disease in susceptible mice. To identify features of central nervous system (CNS) infection that correlate with neurovirulence, we compared two neurovirulent MuLV, Fr98 and Fr98\\/SE, with a nonneurovirulent MuLV, Fr54. All three viruses utilize the polytropic receptor and are coisogenic, each containing a different envelope gene within a common genetic background. Both Fr98

SHELLY J. ROBERTSON; KIM J. HASENKRUG; BRUCE CHESEBRO; JOHN L. PORTIS

1997-01-01

195

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

PubMed

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

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

1998-07-11

196

[Hypotheses on the role of the prehistoric Sahara in the spread of parasitic and hematologic diseases].  

PubMed

15,000 years ago, the Sahara was moist, inhabited by tropical fauna and travelled over by nomadic populations. Later, the dryness incited human migrations to North or West Africa. African bilharziasis (S. mansoni and S. haematobium) could have been carried by nomadic populations infected in the Nile River. Sickle cell disease and alpha-thalassemia are derived from Saudi Arabia (unless in the case of alpha-thalassemia there was an identical mutation in several regions). Echinococcosis was brought with the dromedary in the ptolemaic era whereas ankylostomiasis was brought by the Romans or the Arabs. PMID:3301031

Nozais, J P

1987-01-01

197

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

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. PMID:23465838

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

2013-02-08

198

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

PubMed Central

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

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

2011-01-01

199

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

PubMed

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/?K280 and hTau40/?K280/PP) or the truncated Tau repeat domain (Tau(RD)/?K280 and Tau(RD)/?K280/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/?K280 leads to a 'pre-tangle' pathology, the repeat domain Tau(RD)/?K280 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. PMID:23517246

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

2013-04-22

200

Alveolar echinococcosis-spreading disease challenging clinicians: a case report and literature review.  

PubMed

Human alveolar echinococcosis (AE) is a potentially deadly disease; recent studies have shown that the endemic area of Echinococcus multilocularis, its causative agent, is larger than previously known. This disease has low prevalence and remains underreported in Europe. Emerging clinical data show that diagnostic difficulties are still common. We report on a 76-year old patient suffering from AE lesions restricted to the left lobe of the liver who underwent a curative extended left hemihepatectomy. Prior to the resection a liver biopsy under the suspicion of an atypical malignancy was performed. After the intervention he developed a pseudoaneurysm of the hepatic artery that was successfully coiled. Surprisingly, during surgery, the macroscopic appearance of the tumour revealed a growth pattern that was rather typical for cystic echinococcosis (CE), i.e., a gross tumour composed of multiple large vesicles with several centimeters in diameter. In addition, there were neither extensive adhesions nor infiltrations of the neighboring pancreas and diaphragm as was expected from previous imaging results. The unexpected diagnosis of AE was confirmed by definite histopathology, specific polymerase chain reaction and serology results. This is a rare case of unusual macroscopic presentation of AE that posed immense diagnostic challenges and had an eventful course. To our knowledge this is the first case of an autochthonous infection in this particular geographic area of Germany, the federal state of Saxony. This report may provide new hints for an expanding area of risk for AE and emphasizes the risk of complications in the scope of diagnostic procedures and the limitations of modern radiological imaging. PMID:23864792

Atanasov, Georgi; Benckert, Christoph; Thelen, Armin; Tappe, Dennis; Frosch, Matthias; Teichmann, Dieter; Barth, Thomas F E; Wittekind, Christian; Schubert, Stefan; Jonas, Sven

2013-07-14

201

Alveolar echinococcosis-spreading disease challenging clinicians: A case report and literature review  

PubMed Central

Human alveolar echinococcosis (AE) is a potentially deadly disease; recent studies have shown that the endemic area of Echinococcus multilocularis, its causative agent, is larger than previously known. This disease has low prevalence and remains underreported in Europe. Emerging clinical data show that diagnostic difficulties are still common. We report on a 76-year old patient suffering from AE lesions restricted to the left lobe of the liver who underwent a curative extended left hemihepatectomy. Prior to the resection a liver biopsy under the suspicion of an atypical malignancy was performed. After the intervention he developed a pseudoaneurysm of the hepatic artery that was successfully coiled. Surprisingly, during surgery, the macroscopic appearance of the tumour revealed a growth pattern that was rather typical for cystic echinococcosis (CE), i.e., a gross tumour composed of multiple large vesicles with several centimeters in diameter. In addition, there were neither extensive adhesions nor infiltrations of the neighboring pancreas and diaphragm as was expected from previous imaging results. The unexpected diagnosis of AE was confirmed by definite histopathology, specific polymerase chain reaction and serology results. This is a rare case of unusual macroscopic presentation of AE that posed immense diagnostic challenges and had an eventful course. To our knowledge this is the first case of an autochthonous infection in this particular geographic area of Germany, the federal state of Saxony. This report may provide new hints for an expanding area of risk for AE and emphasizes the risk of complications in the scope of diagnostic procedures and the limitations of modern radiological imaging.

Atanasov, Georgi; Benckert, Christoph; Thelen, Armin; Tappe, Dennis; Frosch, Matthias; Teichmann, Dieter; Barth, Thomas FE; Wittekind, Christian; Schubert, Stefan; Jonas, Sven

2013-01-01

202

MedyMyst: Orientation at O.R.B. Introduction to the six types of pathogens, Koch's Postulates, disease spread, disease prevention measures, and the immune system.  

NSDL National Science Digital Library

This is a problem-based learning adventure game that engages the player in the role of scientist, historian, and detective. Students get an introduction to infectious diseases and pathogens. At the beginning, the student is presented with a problem that must be solved. During the mission, students conduct field and laboratory investigations with the aid of the MedMyst characters. Each mission can be played within one class period (approximately 30 to 45 minutes) and the knowledge gained from each mission will help students understand how infectious diseases are spread. We recommend that Mission One be played first because it covers the basics and serves as an orientation to the concepts and the characters. However, any of the missions may be chosen to follow Mission One. Each mission is a self-contained problem and may be played without reliance on the other missions. Also available in Spanish.

Learning, Center F.

2002-01-01

203

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

Microsoft Academic Search

Individuals with autism spectrum disorder (ASD) reportedly fail to show contagious yawning, but the mechanism underlying the\\u000a lack of contagious yawning is still unclear. The current study examined whether instructed fixation on the eyes modulates\\u000a contagious yawning in ASD. Thirty-one children with ASD, as well as 31 age-matched typically developing (TD) children, observed\\u000a video clips of either yawning or control

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

2009-01-01

204

Contagious yawning and the frontal lobe: an fMRI study.  

PubMed

We conducted a slow event-related fMRI experiment with naïve subjects' passively viewing yawn and various other control videos along with correlative behavioral testing. Specifically associated with the viewing of the contagious yawn was an area of activation in the ventromedial prefrontal cortex. These findings suggest a role for the prefrontal cortex in the processing of contagious yawning, while demonstrating a unique automaticity in the processing of contagious motor programs which take place independently of mirror neuron networks. PMID:18937281

Nahab, Fatta B; Hattori, Noriaki; Saad, Ziad S; Hallett, Mark

2009-05-01

205

Spreading brain lesions in a familial Creutzfeldt-Jakob disease with V180I mutation over 4 years  

PubMed Central

Background We report a female patient with familial Creutzfeldt-Jakob disease with V180I mutation (fCJD with V180I), who was serially followed up with magnetic resonance imaging (MRI) and electroencephalogram (EEG) for up to four years. Case presentation At 6?months after the onset, diffusion-weighted images (DWI) and fluid-attenuated inversion recovery (FLAIR) of brain MRI revealed an increased signal intensity in the bilateral frontal, temporal, and parietal cerebral cortex with left dominancy except for the occipital lobe. However, her follow-up MRI at four years showed the high-signal regions spreading to the occipital cerebral cortex in DWI and FLAIR images, and bilateral frontal cerebral white matter in FLAIR images. EEG showed a progressive and general slow high-voltage rhythm from 7–8 to 3–5 c/s over four years, without evidence of periodic synchronous discharge. These findings correspond to the symptom progression even after akinetic mutism at 18?months. Conclusion We suggest that serial MRI and EEG examinations are useful for early diagnosis of fCJD with V180I and for monitoring disease progression.

2012-01-01

206

Spreading of infectious diseases considering age contact patterns for Latin America  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

207

A predictable sequential determinant spreading cascade invariably accompanies progression of experimental autoimmune encephalomyelitis: a basis for peptide-specific therapy after onset of clinical disease  

PubMed Central

The development of autoimmune disease is accompanied by the acquired recognition of new self-determinants, a process commonly referred to as determinant spreading. In this study, we addressed the question of whether determinant spreading is pathogenic for progression of chronic- relapsing experimental autoimmune encephalomyelitis (EAE), a disease with many similarities to multiple sclerosis (MS). Our approach involved a systematic epitope mapping of responses to myelin proteolipid protein (PLP) as well as assaying responses to known encephalitogenic determinants of myelin basic protein (MBP 87-89) and myelin oligodendrocyte glycoprotein (MOG 92-106) at various times after induction of EAE in (SWR X SJL)F1 mice immunized with PLP 139-151. We found that the order in which new determinants are recognized during the course of disease follows a predictable sequential pattern. At monthly intervals after immunization with p139-151, responses to PLP 249-273, MBP 87-99, and PLP 137-198 were sequentially accumulated in al mice examined. Three lines of evidence showed that determinant spreading is pathogenic for disease progression: (a) spreading determinants mediate passive transfer of acute EAE in naive (SWR X SJL)F1 recipients; (b) an invariant relationship exists between the development of relapse/progression and the spreading of recognition to new immunodominant encephalitogenic determinants; and (c) after EAE onset, the induction of peptide-specific tolerance to spreading but not to nonspreading encephalitogenic determinants prevents subsequent progression of EAE. Thus, the predictability of acquired self- determinant recognition provides a basis for sequential determinant- specific therapeutic intervention after onset of the autoimmune disease process.

1996-01-01

208

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

PubMed

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. PMID:20357468

Platek, Steven M

2010-03-26

209

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

PubMed Central

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.

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

2009-01-01

210

On the Origin and Spread of the Scab Disease of Apple: Out of Central Asia  

PubMed Central

Background Venturia inaequalis is an ascomycete fungus responsible for apple scab, a disease that has invaded almost all apple growing regions worldwide, with the corresponding adverse effects on apple production. Monitoring and predicting the effectiveness of intervention strategies require knowledge of the origin, introduction pathways, and population biology of pathogen populations. Analysis of the variation of genetic markers using the inferential framework of population genetics offers the potential to retrieve this information. Methodology/Principal Findings Here, we present a population genetic analysis of microsatellite variation in 1,273 strains of V. inaequalis representing 28 orchard samples from seven regions in five continents. Analysis of molecular variance revealed that most of the variation (88%) was distributed within localities, which is consistent with extensive historical migrations of the fungus among and within regions. Despite this shallow population structure, clustering analyses partitioned the data set into separate groups corresponding roughly to geography, indicating that each region hosts a distinct population of the fungus. Comparison of the levels of variability among populations, along with coalescent analyses of migration models and estimates of genetic distances, was consistent with a scenario in which the fungus emerged in Central Asia, where apple was domesticated, before its introduction into Europe and, more recently, into other continents with the expansion of apple growing. Across the novel range, levels of variability pointed to multiple introductions and all populations displayed signatures of significant post-introduction increases in population size. Most populations exhibited high genotypic diversity and random association of alleles across loci, indicating recombination both in native and introduced areas. Conclusions/Significance Venturia inaequalis is a model of invasive phytopathogenic fungus that has now reached the ultimate stage of the invasion process with a broad geographic distribution and well-established populations displaying high genetic variability, regular sexual reproduction, and demographic expansion.

Gladieux, Pierre; Zhang, Xiu-Guo; Afoufa-Bastien, Damien; Valdebenito Sanhueza, Rosa-Maria; Sbaghi, Mohamed; Le Cam, Bruno

2008-01-01

211

Pathogenesis of Borna disease in rats: evidence that intra-axonal spread is the major route for virus dissemination and the determinant for disease incubation.  

PubMed Central

Borna disease virus is an uncharacterized agent that causes sporadic but fatal neurological disease in horses and sheep in Europe. Studies of the infection in rats have shown that the agent has a strict tropism for neural tissues, in which it persists indefinitely. Inoculated rats developed encephalitis after an incubation period of 17 to 90 days. This report shows that the incubation period is the time required for transport of the agent in dendritic-axonal processes from the site of inoculation to the hippocampus. The immune responses to the agent had no effect on replication or transport of the virus. The neural conduit to the brain was proven by intranasal inoculation of virus that resulted in rapid transport of the agent via olfactory nerves to the hippocampus and in development of disease in 20 days. Virus inoculation into the feet resulted in spread along nerve fibers from neuron to neuron. There was sequential replication in neurons of the dorsal root ganglia adjacent to the lumbar spinal cord, the gracilis nucleus in the medulla, and pyramidal cells in the cerebral cortex, followed by infection of the hippocampal neurons and onset of disease. This progression required 50 to 60 days. The exclusiveness of the neural conduit was proven by failure to cause infection after injection of the virus intravenously or into the feet of neurectomized rats. Images

Carbone, K M; Duchala, C S; Griffin, J W; Kincaid, A L; Narayan, O

1987-01-01

212

Hitting Is Contagious in Baseball: Evidence from Long Hitting Streaks  

PubMed Central

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.

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

2012-01-01

213

Ingroup-Outgroup Bias in Contagious Yawning by Chimpanzees Supports Link to Empathy  

Microsoft Academic Search

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

Matthew W. Campbell; Frans B. M. de Waal; Georges Chapouthier

2011-01-01

214

Contagious yawning: the role of self-awareness and mental state attribution.  

PubMed

Contagious yawning is a common, but poorly understood phenomenon. We hypothesized that contagious yawning is part of a more general phenomenon known as mental state attribution (i.e. the ability to inferentially model the mental states of others). To test this hypothesis we compared susceptibility to contagiously yawn with performance on a self-face recognition task, several theory of mind stories, and on a measure of schizotypal personality traits. Consistent with the hypothesis, susceptibility to contagiously yawn was positively related to performance on self-face recognition and faux pas theory of mind stories, and negatively related to schizotypal personality traits. These data suggest that contagious yawning may be associated with empathic aspects of mental state attribution and are negatively affected by increases in schizotypal personality traits much like other self-processing related tasks. PMID:12880893

Platek, Steven M; Critton, Samuel R; Myers, Thomas E; Gallup, Gordon G

2003-07-01

215

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

PubMed

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. PMID:23564365

Bagrowicz, Rinako; Watanabe, Chiho; Umezaki, Masahiro

2013-10-01

216

Spreading volcanoes  

USGS Publications Warehouse

As volcanoes grow, they become ever heavier. Unlike mountains exhumed by erosion of rocks that generally were lithified at depth, volcanoes typically are built of poorly consolidated rocks that may be further weakened by hydrothermal alteration. The substrates upon which volcanoes rest, moreover, are often sediments lithified by no more than the weight of the volcanic overburden. It is not surprising, therefore, that volcanic deformation includes-and in the long term is often dominated by-spreading motions that translate subsidence near volcanic summits to outward horizontal displacements around the flanks and peripheries. We review examples of volcanic spreading and go on to derive approximate expressions for the time volcanoes require to deform by spreading on weak substrates. We also demonstrate that shear stresses that drive low-angle thrust faulting from beneath volcanic constructs have maxima at volcanic peripheries, just where such faults are seen to emerge. Finally, we establish a theoretical basis for experimentally derived scalings that delineate volcanoes that spread from those that do not.

Borgia, A.; Delaney, P. T.; Denlinger, R. P.

2000-01-01

217

Phytophthora ramorum Isolated From California Bay Laurel Inflorescences and Mistletoe: Possible Implications Relating to Disease Spread 1  

Microsoft Academic Search

Since 2005, we have been studying the spread and development of Phytophthora ramorum at a Christmas tree farm near Los Gatos, California. This research has shown that distance from infected plants, predominantly California bay laurel (Umbellularia californica) (referred to as 'bay' throughout), is an important factor relating to the infection of Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis) Christmas

Gary A. Chastagner; Kathy Riley; Norm Dart

218

INCORPORATION OF DISTANCE-OF-SPREAD CALCULATIONS INTO A WEATHER-BASED MODEL DESCRIBING DISEASE DISTRIBUTION AFTER SEVERE WEATHER EVENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

In Florida, Asiatic citrus canker (Xanthomonas axonopodis pv. citri, XAC) has a long history of multiple introductions followed by eradication campaigns. The latest eradication campaign began in 1995 and continued through 2005 until regulatory agencies concluded that citrus canker had spread to the...

219

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

PubMed

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. PMID:19533316

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

2009-06-16

220

Ingroup-Outgroup Bias in Contagious Yawning by Chimpanzees Supports Link to Empathy  

PubMed Central

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.

Campbell, Matthew W.; de Waal, Frans B. M.

2011-01-01

221

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

PubMed

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. PMID:21494669

Campbell, Matthew W; de Waal, Frans B M

2011-04-06

222

Flu and Heart Disease  

MedlinePLUS

... contagious illness, which is caused by influenza viruses. Flu vaccines are created to combat the strains of flu ... American College of Cardiology has recommended an annual flu vaccine in injection form for cardiovascular disease patients “with ...

223

A history of the prevalence and control of contagious bovine pleuropneumonia in China.  

PubMed

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides small colony type, was once the most damaging infectious animal disease in China, second only to rinderpest. Between 1949 and 1989, 178,570 cattle died of CBPP, causing estimated losses of 356 million RMB (1RMB=approx. £0.094, US$0.15, €0.11 at 27th January 2011). In 1956, in an effort to control the disease, a virulent strain of the causative organism (Ben-1) was attenuated by multiple passages in rabbits. The resultant vaccine achieved a high protection rate in cattle with a duration of immunity of 28 months. Vaccines were also prepared in sheep to increase the antigen yield and then in Tibetan sheep because it caused fewer adverse reactions in yaks and related species. The last CBPP infected animal was identified in 1989 since when no more cases have occurred. In 1992, vaccination of cattle was stopped. In 2008 China submitted an application to the World Organization for Animal Health (OIE) to be declared CBPP-free. PMID:21439870

Xin, Jiuqing; Li, Yuan; Nicholas, Robin A J; Chen, Chao; Liu, Yang; Zhang, Mei-Jing; Dong, Hui

2011-03-24

224

A long-term study of a patient with anti-p200 pemphigoid: correlation of autoantibody levels with disease activity and an example of epitope spreading.  

PubMed

Anti-p200 pemphigoid is a rare subepidermal blistering disease associated with autoantibodies against a 200-kDa protein, reportedly corresponding to laminin ?1. However, direct evidence of the pathogenic potential of these antibodies has not been proven. For 5 years we have followed up a patient with anti-p200 pemphigoid. During this period she experienced a total of three generalized relapses. Quantifying our patient's autoantibody concentrations against laminin ?1 by enzyme-linked immunosorbent assay throughout the course of her disease we demonstrated a clear correlation with disease activity, thus providing the first evidence of the possible pathogenic role of antibodies against laminin ?1 in anti-p200 pemphigoid. Further analysis by Western blotting revealed the occurrence of additional autoantibodies against the ?3 chain of laminin 332, 1·5 years after diagnosis, suggestive of intermolecular epitope spreading. Yet, the clinical appearance was unchanged and mucous membranes remained unaffected at any stage of the disease. PMID:22639938

Monshi, B; Groth, S; Richter, L; Schmidt, E; Zillikens, D; Rappersberger, K

2012-11-01

225

The daily time course of contagious and spontaneous yawning among humans  

Microsoft Academic Search

Yawning, besides being a spontaneous behavior, can also be evoked by observing others yawn. However, contagious yawning does\\u000a not always occur, depending possibly on several factors, such as one’s propensity to spontaneously yawn and a heightened level\\u000a of sleepiness. The aim of this study is to investigate in young adults whether contagious yawning frequency varies throughout\\u000a the day, and if

Fiorenza Giganti; Iole Zilli

2011-01-01

226

Contagious seed dispersal beneath heterospecific fruiting trees and its consequences.  

SciTech Connect

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.

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

2004-05-03

227

Disease-avoidant behaviour and its consequences  

Microsoft Academic Search

Medical conditions that are non-contagious, but that appear contagious, seem to result in the sufferer being avoided. Error management theory (EMT), suggests that such false alarms occur because the cost of infection poses a greater threat to ones fitness than avoidance. Study 1 attempted to demonstrate a disease-related false alarm effect by asking participants, to evaluate a series of vignettes,

Daria Kouznetsova; Richard J. Stevenson; Megan J. Oaten; Trevor I. Case

2011-01-01

228

Disease-avoidant behaviour and its consequences  

Microsoft Academic Search

Medical conditions that are non-contagious, but that appear contagious, seem to result in the sufferer being avoided. Error management theory (EMT), suggests that such false alarms occur because the cost of infection poses a greater threat to ones fitness than avoidance. Study 1 attempted to demonstrate a disease-related false alarm effect by asking participants, to evaluate a series of vignettes,

Daria Kouznetsova; Richard J. Stevenson; Megan J. Oaten; Trevor I. Case

2012-01-01

229

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

PubMed

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

Romero, Teresa; Konno, Akitsugu; Hasegawa, Toshikazu

2013-08-07

230

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

PubMed

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. PMID:22830597

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

2012-07-26

231

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

PubMed

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 perspective. PMID:23462679

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

2013-02-22

232

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

PubMed Central

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

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

2013-01-01

233

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

Microsoft Academic Search

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

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

2006-01-01

234

[Skrljevo disease in Slovenia].  

PubMed

During the first decades of the 19th century a disease appeared in the regions of Inner Carniola and Carst which was, due to its unusual course, at first considered a new entity. It spread among the population in an asexual, extragenital and endemic way and was enhanced by poor economic and hygienic circumstances. Since the clinical picture of the disease resembled sporadic syphilis, some doctors thought that it was a combination of syphilis and some others contagious disease, while others considered it sporadic syphilis. The government in Vienna responded to the epidemic by the introduction of extensive social and health measures. Compulsory medical examination of the inhabitants in the affected area was decreed, treatment of patients was initiated and preventive measures recommended. The action was organized by Baron Dr. Stifft. In the summer of 1818 a new specialized hospital for Skerljevo's patients was opened in Postojna. When the epidemic declined a decade later the hospital was closed down. Extensive preventive and curative actions, and the efforts of local authorities and clergy to improve living conditions of Slovenian peasant population and make them more aware of the seriousness and causes of the disease contributed to the decline of the epidemic. The example set by organization of the official measures taken in the case of Skerljevo disease can serve as a basis for a comparative medico-historical study regarding new epidemic diseases (AIDS, diseases caused by slow viruses). PMID:12152416

Slavec, Zvonka Zupanic

2002-05-01

235

Spread Supersymmetry  

NASA Astrophysics Data System (ADS)

In the multiverse the scale of supersymmetry breaking, widetilde{m} = {F_X}/{M_{ * }} ?, may scan and environmental constraints on the dark matter density may exclude a large range of m from the reheating temperature after inflation down to values that yield a lightest supersymmetric particle (LSP) mass of order a TeV. After selection effects, for example from the cosmological constant, the distribution for widetilde{m} in the region that gives a TeV LSP may prefer larger values. A single environmental constraint from dark matter can then lead to multi-component dark matter, including both axions and the LSP, giving a TeV-scale LSP somewhat lighter than the corresponding value for single-component LSP dark matter. If supersymmetry breaking is mediated to the Standard Model sector at order X † X and higher, only squarks, sleptons and one Higgs doublet acquire masses of order widetilde{m} . The gravitino mass is lighter by a factor of M ? /M Pl and the gaugino masses are suppressed by a further loop factor. This Spread Supersymmetry spectrum has two versions, one with Higgsino masses arising from supergravity effects of order the gravitino mass giving a wino LSP, and another with the Higgsino masses generated radiatively from gaugino masses giving a Higgsino LSP. The environmental restriction on dark matter fixes the LSP mass to the TeV domain, so that the squark and slepton masses are order 103 TeV and 106 TeV in these two schemes. We study the spectrum, dark matter and collider signals of these two versions of Spread Supersymmetry. The Higgs boson is Standard Model-like and predicted to lie in the range 110-145 GeV; monochromatic photons in cosmic rays arise from dark matter annihilations in the halo; exotic short charged tracks occur at the LHC, at least for the wino LSP; and there are the eventual possibilities of direct detection of dark matter and detailed exploration of the TeV-scale states at a future linear collider. Gauge coupling unification is at least as precise as in minimal supersymmetric theories. If supersymmetry breaking is also mediated at order X, a much less hierarchical spectrum results. The spectrum in this case is similar to that of the Minimal Supersymmetric Standard Model, but with the superpartner masses 1-2 orders of magnitude larger than those expected in natural theories.

Hall, Lawrence J.; Nomura, Yasunori

2012-01-01

236

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

PubMed

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

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

2009-11-04

237

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)

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.

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

238

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)

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.

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

239

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

SciTech Connect

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.

McKenna, S.A.

2000-11-01

240

A simulation spatial model of the spread of foot-and-mouth disease through the primary movement of milk.  

PubMed Central

A computer model was constructed to mimic the 1967-8 foot-and-mouth epizootic in Shropshire and Cheshire, but the daily spatial distribution of outbreaks was randomized. This pattern of outbreaks was then examined to determine what percentage of outbreaks would fulfil and arbitrary set of criteria for milk-lorry-borne disease, or the primary movement of milk. Some 21% of herds visited subsequent to a 'source farm' were affected, as were 4% of herds visited after any infected herd. The relevance of these results to the true risk of disease through the primary movement of milk off affected farms is discussed.

Hugh-Jones, M. E.

1976-01-01

241

Yawning as a Brain Cooling Mechanism: Nasal Breathing and Forehead Cooling Diminish the Incidence of Contagious Yawning  

Microsoft Academic Search

We conducted two experiments that implicate yawning as a thermoregulatory mechanism. The first experiment demonstrates that different patterns of breathing influence susceptibility to contagious yawning. When participants were not directed how to breathe or were instructed to breathe orally (inhaling and exhaling through their mouth), the incidence of contagious yawning in response to seeing videotapes of people yawning was about

Andrew C. Gallup; Gordon G. Gallup Jr

242

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

243

Emergence, spread and strategies for controlling the pandemic of cassava mosaic virus disease in east and central Africa  

Microsoft Academic Search

During the 1990s, an epidemic of an unusually severe form of cassava mosaic virus disease (CMD) has expanded to cover virtually all of Uganda, and substantial areas in the neighbouring countries of Kenya, Tanzania, Sudan and the Democratic Republic of Congo. Losses in the generally sensitive local cassava cultivars have been so great that a common farmer response to the

J. P Legg

1999-01-01

244

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

|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…

DiSpezio, Michael A.

245

The Arabidopsis-accelerated cell death gene ACD2 encodes red chlorophyll catabolite reductase and suppresses the spread of disease symptoms  

PubMed Central

accelerated cell death 2 (acd2) mutants of Arabidopsis have spontaneous spreading cell death lesions and constitutive activation of defenses in the absence of pathogen infection. Lesion formation in acd2 plants can be triggered by the bacterial toxin coronatine through a light-dependent process. Coronatine-triggered and spontaneous lesion spreading in acd2 plants also requires protein translation, indicating that cell death occurs by an active process. We have cloned the ACD2 gene; its predicted product shows significant and extensive similarity to red chlorophyll catabolite reductase, which catalyzes one step in the breakdown of the porphyrin component of chlorophyll [Wüthrich, K. L., Bovet, L., Hunziger, P. E., Donnison, I. S. & Hörtensteiner, S. (2000) Plant J. 21, 189–198]. Consistent with this, ACD2 protein contains a predicted chloroplast transit peptide, is processed in vivo, and purifies with the chloroplast fraction in subcellular fractionation experiments. At some stages of development, ACD2 protein also purifies with the mitochondrial fraction. We hypothesize that cell death in acd2 plants is caused by the accumulation of chlorophyll breakdown products. Such catabolites might be specific triggers for cell death or they might induce cellular damage through their ability to absorb light and emit electrons that generate free radicals. In response to infection by Pseudomonas syringae, transgenic plants expressing excess ACD2 protein show reduced disease symptoms but not reduced growth of bacteria. Thus, breakdown products of chlorophyll may act to amplify the symptoms of disease, including cell death and yellowing. We suggest that economically important plants overexpressing ACD2 might also show increased tolerance to pathogens and might be useful for increasing crop yields.

Mach, Jennifer M.; Castillo, Andrea R.; Hoogstraten, Rebecca; Greenberg, Jean T.

2001-01-01

246

Elevated temperature and light enhance progression and spread of black band disease on staghorn corals of the Great Barrier Reef  

Microsoft Academic Search

Rates of progression and transmission of black band disease (BBD) on the staghorn coral, Acropora muricata, were compared between months for seasonal in situ studies and between temperature treatments in experimental aquaria manipulations\\u000a at Lizard Island on the Great Barrier Reef (GBR). In situ field experiments demonstrated that BBD progressed along branches\\u000a approximately twice as fast (1.7–2.4 times) during the

Holly V. Boyett; David G. Bourne; Bette L. Willis

2007-01-01

247

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

ERIC Educational Resources Information Center

|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…

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

2007-01-01

248

A competitive ELISA for the specific diagnosis of contagious bovine pleuropneumonia (CBPP)  

Microsoft Academic Search

A competitive ELISA, using a specific monoclonal antibody, was designed to detect antibodies to Mycoplasma mycoides subsp. mycoides SC, the agent of contagious bovine pleuropneumonia. One monoclonal antibody was found suitable for such a test, `117\\/5', it does not cross-react with any of the other mycoplasma species tested, furthermore, its binding is inhibited by positive sera. The cutoff, 50% of

C Le Goff; F Thiaucourt

1998-01-01

249

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

ERIC Educational Resources Information Center

|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…

Raman, Lakshmi; Gelman, Susan A.

2005-01-01

250

CONFIRMATORY DIAGNOSIS OF CONTAGIOUS ECTHYMA BY AMPLIFICATION OF THE GIF \\/ IL2 GENE BY PCR  

Microsoft Academic Search

A polymerase Chain reaction (PCR) assay for rapid diagnosis of contagious ecthyma (CE) was applied to 55 scab samples obtained from suspected CE outbreaks among sheep and goats. This assay used the CE virus specific primers for GIF\\/IL-2 gene - a highly conserved gene of parapox genome to diagnose CE and also the assay was evaluated for its sensitivity and

A. Ramesh; V. S. Vadivoo; S. Suresh Babu; K. Saravanabava

251

Laboratory diagnosis of contagious ecthyma: Comparison of different PCR protocols with virus isolation in cell culture  

Microsoft Academic Search

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

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

2006-01-01

252

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

PubMed

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. PMID:22209955

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

2011-12-28

253

Prevention of the contagious spread of feline leukaemia virus and the development of leukaemia in pet cats  

Microsoft Academic Search

CLUSTERING of cases of feline lymphosarcoma (LSA) or leukaemia has been observed by veterinarians for many years1-4. The first anti-feline leukaemia virus (FeLV) serum was reported in 19695 and by 1970 a simple indirect immunofluores-cent antibody (IFA) test for the detection of FeLV in the peripheral blood of infected cats had been developed6. Using this test we found that 33%

W. D. Hardy; A. J. McClelland; E. E. Zuckerman

1976-01-01

254

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

PubMed

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

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

2004-12-01

255

Spread of SARS  

NSDL National Science Digital Library

In this module, we develop a simplified model (SIR) of the spread of an infectious disease before considering a more involved model of SARS. For the former, after analyzing the system and formulating the model with appropriate differential equations, we create a model using the systems modeling tool STELLA. For the latter, we build on the earlier model to perform the analysis and much of the model formulation, but leave the completion of the model to the student. Projects involve various refinements of the models along with additional problems.

Shiflet, Angela B.; Shiflet, George W.

256

Exploring farmer preferences for contagious bovine pleuropneumonia vaccination: a case study of Narok District of Kenya.  

PubMed

Contagious bovine pleuropneumonia (CBPP) is an economically important disease in most of sub-Saharan Africa. A conjoint analysis and ordered probit regression models were used to measure the preferences of farmers for CBPP vaccine and vaccination attributes. This was with regard to inclusion or not of an indicator in the vaccine, vaccine safety, vaccine stability as well as frequency of vaccination, vaccine administration and the nature of vaccination. The analysis was carried out in 190 households in Narok District of Kenya between October and December 2006 using structured questionnaires, 16 attribute profiles and a five-point Likert scale. The factors affecting attribute valuation were shown through a two-way location interaction model. The study also demonstrated the relative importance (RI) of attributes and the compensation value of attribute levels. The attribute coefficient estimates showed that farmers prefer a vaccine that has an indicator, is 100% safe and is administered by the government (p<0.0001). The preferences for the vaccine attributes were consistent with expectations. Preferences for stability, frequency of vaccination and nature of vaccination differed amongst farmers (p>0.05). While inclusion of an indicator in the vaccine was the most important attribute (RI=43.6%), price was the least important (RI=0.5%). Of the 22 household factors considered, 15 affected attribute valuation. The compensation values for a change from non inclusion to inclusion of an indicator, 95-100% safety, 2h to greater than 2h stability and from compulsory to elective vaccination were positive while those for a change from annual to biannual vaccination and from government to private administration were negative. The study concluded that the farmers in Narok District had preferences for specific vaccine and vaccination attributes. These preferences were conditioned by various household characteristics and disease risk factors. On average the farmers would need to be compensated or persuaded to accept biannual and private vaccination against CBPP. There is need for consideration of farmer preferences for vaccine attribute levels during vaccine formulations and farmer preferences for vaccination attribute levels when designing delivery of vaccines. PMID:23465609

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

2013-03-05

257

Screwworms, Cochliomyia hominivorax, Reared for Mass Release Do Not Carry and Spread Foot-and-Mouth Disease Virus and Classical Swine Fever Virus  

PubMed Central

Experiments were done to determine if transporting live screwworms Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae) for developing new strains from countries where foot-and-mouth disease and classical swine fever are endemic, to the mass rearing facilities in Mexico and Panama, may introduce these exotic diseases into these countries. Are screwworms capable of harboring and spreading foot-and-mouth disease virus (FMDV) and classical swine fever virus (CSFV) when they are grown in virus-inoculated larval rearing medium? In one experiment, screwworm larvae were reared in a FMDV-inoculated artificial medium containing either 0.1 % formaldehyde or antibiotics as an antimicrobial agent. In another experiment, larvae were similarly reared in a CSFV-inoculated artificial medium containing 0.1% formaldehyde. In each experiment, samples of larvae and the rearing media were collected daily until pupation occurred. The presence of FMDV was assayed by observing cytopathic effects on cell cultures and a conventional reverse transcription-polymerase chain reaction (RT-PCR); CSFV was assayed using an avidin-biotin complex assay and a conventional RT-PCR. For media containing antibiotics, FMDV was detected in a larval sample collected on day 1 and in media samples on days 1, 2 and 3. No FMDV was detected from larval and media samples collected on all other days. For media containing formaldehyde, FMDV and CSFV were not detectable in larval or media samples collected on all sampling days. These results indicate that FMDV and CSFV cannot survive in rearing medium containing formaldehyde as an antimicrobial agent. Therefore, insects collected in endemic regions and reared using formaldehyde-containing medium for at least one generation at the collection site should be free of FMDV and CSFV and can be transported safely to a strain development/mass rearing facility.

Chaudhury, M. F.; Ward, G. B.; Skoda, S. R.; Deng, M.Y.; Welch, J. B.; McKenna, T. S.

2008-01-01

258

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

PubMed

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. PMID:23759248

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

2013-06-01

259

Multi-locus sequence analysis of mycoplasma capricolum subsp. capripneumoniae for the molecular epidemiology of contagious caprine pleuropneumonia  

PubMed Central

Mycoplasma capricolum subsp. capripneumoniae (Mccp) is the causative agent of contagious caprine pleuropneumonia (CCPP), a devastating disease of domestic goats. The exact distribution of CCPP is not known but it is present in Africa and the Middle East and represents a significant threat to many disease-free areas including Europe. Furthermore, CCPP has been recently identified in Tajikistan and China. A typing method with an improved resolution based on Multi-Locus Sequence Analysis (MLSA) has been developed to trace new epidemics and to elucidate whether the recently identified cases in continental Asia were due to recent importation of Mccp. The H2 locus, a polymorphic region already in use as a molecular marker for Mccp evolution, was complemented with seven new loci selected according to the analysis of polymorphisms observed among the genome sequences of three Mccp strains. A total of 25 strains, including the two new strains from Asia, were analysed by MLSA resulting in the discrimination of 15 sequence types based on 53 polymorphic positions. A distance tree inferred from the concatenated sequences of the eight selected loci revealed two evolutionary lineages comprising five groups, which showed good correlation with geographic origins. The presence of a distinct Asian cluster strongly indicates that CCPP was not recently imported to continental Asia. It is more likely that the disease has been endemic in the area for a long time, as supported by historical clinical descriptions. In conclusion, this MLSA strategy constitutes a highly discriminative tool for the molecular epidemiology of CCPP.

2011-01-01

260

Marek's disease virus morphogenesis.  

PubMed

Marek's disease virus (MDV) is a highly contagious virus that induces T-lymphoma in chicken. This viral infection still circulates in poultry flocks despite the use of vaccines. With the emergence of new virulent strains in the field over time, MDV remains a serious threat to the poultry industry. More than 40 yr after MDV identification as a herpesvirus, the visualization and purification of fully enveloped infectious particles remain a challenge for biologists. The various strategies used to detect such hidden particles by electron microscopy are reviewed herein. It is now generally accepted that the production of cell-free virions only occurs in the feather follicle epithelium and is associated with viral, cellular, or both molecular determinants expressed in this tissue. This tissue is considered the only source of efficient virus shedding into the environment and therefore the origin of successful transmission in birds. In other avian tissues or permissive cell cultures, MDV replication only leads to a very low number of intracellular enveloped virions. In the absence of detectable extracellular enveloped virions in cell culture, the nature of the transmitted infectious material and its mechanisms of spread from cell to cell remain to be deciphered. An attempt is made to bring together the current knowledge on MDV morphogenesis and spread, and new approaches that could help understand MDV morphogenesis are discussed. PMID:23901745

Denesvre, Caroline

2013-06-01

261

Epizootic Haemorrhagic Disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Epizootic haemorrhagic disease (EHD) is an infectious non contagious viral disease transmitted by insects of the genus Culicoides which affects wild and domestic ruminants. The causative agent, the epizootic haemorrhagic disease virus (EHDV), belongs to the family Reoviridae, genus Orbivirus and sha...

262

Plagued by kindness: contagious sympathy in Shakespearean drama.  

PubMed

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. PMID:21890861

Langley, Eric

2011-09-02

263

BBC News In Depth: Foot and Mouth Disease  

NSDL National Science Digital Library

Foot and mouth disease is a highly contagious but not necessarily fatal viral infection that is transmitted through dust particles in the air, infecting the hooves and mouths of pigs, cattle, sheep, and goats. In recent weeks, a string of cases have been reported in England, sparking fears of another repeat of the epidemic of 1967, in which over 400,000 animals were destroyed. Farmers and government officials have so far followed the standard plan for dealing with such outbreaks: isolate affected farms and destroy infected herds. As part of this effort, local authorities have been empowered to prevent all foot traffic in designated areas and there has even been talk of delaying the impending general election in Britain for fear that politicians and staff on the campaign trail might spread the disease. This site, a special report from the BBC, contains breaking news, analysis, background information, and audio and video selections.

2001-01-01

264

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

PubMed

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

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

2012-04-19

265

The genome sequence of Mycoplasma mycoides subsp. mycoides SC type strain PG1T, the causative agent of contagious bovine pleuropneumonia (CBPP).  

PubMed

Mycoplasma mycoides subsp. mycoidesSC (MmymySC)is the etiological agent of contagious bovine pleuropneumonia (CBPP), a highly contagious respiratory disease in cattle. The genome of Mmymy SC type strain PG1(T) has been sequenced to map all the genes and to facilitate further studies regarding the cell function of the organism and CBPP. The genome is characterized by a single circular chromosome of 1211703 bp with the lowest G+C content (24 mole%)and the highest density of insertion sequences (13% of the genome size)of all sequenced bacterial genomes. The genome contains 985 putative genes, of which 72 are part of insertion sequences and encode transposases. Anomalies in the GC-skew pattern and the presence of large repetitive sequences indicate a high genomic plasticity. A variety of potential virulence factors was identified, including genes encoding putative variable surface proteins and enzymes and transport proteins responsible for the production of hydrogen peroxide and the capsule, which is believed to have toxic effects on the animal. PMID:14762060

Westberg, Joakim; Persson, Anja; Holmberg, Anders; Goesmann, Alexander; Lundeberg, Joakim; Johansson, Karl-Erik; Pettersson, Bertil; Uhlén, Mathias

2004-02-01

266

The value of animal movement tracing: a case study simulating the spread and control of foot-and-mouth disease in California.  

PubMed

The purpose of this study was to estimate the benefits of an electronic animal tracing system and an improved paper-based system in terms of the potential spread of foot-and-mouth disease (FMD) if introduced in California. A spatial, stochastic simulation model and data for California were used to simulate FMD outbreaks originating from a dairy herd as the index case (IC). Descriptive statistics of the simulated FMD outbreak extent and duration were examined to determine the benefit of an electronic system or paper-based tracing systems of varying efficacies. According to the simulations, an electronic tracing system would reduce the median number of infected premises (IPs) by 8-81%, depending on size of the IC herd compared with the results expected from identifying IPs based on clinical signs alone. The benefit also varied by IP herd type, e.g. ? 50% for sheep farms, goat farms and calf and heifer raising operations and ? 20% for swine and beef premises. The electronic system simulated a decrease in the median duration from at least 200d to 42d, if the IC were a small dairy and from 110d to 45d if the IC were a large dairy. The impact of an introduction of FMD in California could be reduced substantially even without an electronic system, if paper-based tracing were more efficient; however, these benefits are far less than those that could be realized from an electronic animal identification system. Results show that substantial benefits, in terms of fewer IPs and infected animals and reduced epidemic duration, may be realized as a result of an efficient electronic animal identification system, compared with a paper-based animal tracing system; however, until then, an improvement in the current system, especially regarding the ability to trace movements the day prior to a premises being diagnosed with FMD, may be highly beneficial. PMID:23260796

Mardones, F O; Zu Donha, H; Thunes, C; Velez, V; Carpenter, T E

2012-12-20

267

Quantum Spread Spectrum Communication  

SciTech Connect

We show that communication of single-photon quantum states in a multi-user environment is improved by using spread spectrum communication techniques. We describe a framework for spreading, transmitting, despreading, and detecting single-photon spectral states that mimics conventional spread spectrum techniques. We show in the cases of inadvertent detection, unintentional interference, and multi-user management, that quantum spread spectrum communications may minimize receiver errors by managing quantum channel access.

Humble, Travis S [ORNL

2011-01-01

268

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

PubMed Central

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.

Bolske, G; Mattsson, J G; Bascunana, C R; Bergstrom, K; Wesonga, H; Johansson, K E

1996-01-01

269

How Is Mono Spread?  

MedlinePLUS

... I Improve My Self-Esteem? How Is Mono Spread? KidsHealth > Teens > Q&A > Mononucleosis > How Is Mono Spread? Print A A A Text Size My sister ... have mono now? - Kyle* Mono, or mononucleosis, is spread through direct contact with saliva. This includes sharing ...

270

Cell mediated innate responses of cattle and swine are diverse during foot-and-mouth disease virus (FMDV) infection: a unique landscape of innate immunity.  

PubMed

Pathogens in general and pathogenic viruses in particular have evolved a myriad of mechanisms to escape the immune response of mammalian species. Viruses that cause acute disease tend to bear characteristics that make them very contagious, as survival does not derive from chronicity of infection, but spread of disease throughout the herd. Foot-and-mouth disease virus (FMDV) is one of the most contagious viruses known. Upon infection of susceptible species, cloven-hoofed animals, the virus proliferates rapidly and causes a vesicular disease within 2-4 days. Disease symptoms resolve by 10 days to 2 weeks and in most cases, virus can no longer be detected. Periods of fever and viremia are usually brief, 1-3 days. In vivo control of virus infection and clearance of the virus during and following acute infection is of particular interest. The interaction of this virus with cells mediating the early, innate immune response has been analyzed in a number of recent studies. In most reports, the virus has a distinct inhibitory effect on the response of cells early in infection. Here we review these new data and discuss the dynamics of the interaction of virus with different cell types mediating the immune response to infection. PMID:23727070

Toka, Felix N; Golde, William T

2013-05-30

271

Reducing influenza spreading over the airline network  

PubMed Central

Disease spreading through human travel networks has been a topic of great interest in recent years, such as with swine in?uenza or SARS pandemics. Most studies have proposed removing highly connected nodes (hubs) to control spreading. Here, we test alternative strategies using edge removal (?ight cancellation) for spreading over the airline network. Flight cancellation was more ef?cient than shutting down whole airports: spreading took 81% longer if solely selected ?ights were removed, compared to a 52% reduction when entire airports were shutdown, affecting the same number of ?ights.

Marcelino, Jose; Kaiser, Marcus

2009-01-01

272

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

PubMed Central

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

Dupuy, Virginie; Manso-Silvan, Lucia; Barbe, Valerie; Thebault, Patricia; Dordet-Frisoni, Emilie; Citti, Christine; Poumarat, Francois; Blanchard, Alain; Breton, Marc; Sirand-Pugnet, Pascal; Thiaucourt, Francois

2012-01-01

273

Characterization of the major antigens of Haemophilus equigenitalis (contagious equine metritis organism).  

PubMed Central

Immunoelectrophoresis of ultrasonically disrupted Haemophilus equigenitalis (contagious equine metritis organism) cells against rabbit and equine antisera disclosed at least 11 precipitating antigens. Two of these, a polysaccharide and a lipopolysaccharide-protein complex, were of high molecular weight and located on the cell surface. The remaining antigens were intracellular and were small- to medium-sized proteins. The surface antigens were the most significant in relation to the serological response in infected horses. They also reacted with sera from apparently healthy cattle, but the reason for this was not determined. No serological cross-reaction between H. equigenitalis and species of Achromobacter and Moraxella was detected. Images Plate 2 Plate 1 Plate 3

Corbel, M. J.; Brewer, R. A.

1982-01-01

274

Emission of alarm pheromone in aphids: a non-contagious phenomenon.  

PubMed

In response to attack by natural enemies, most aphid species release an alarm pheromone that causes nearby conspecifics to cease feeding and disperse. The primary component of the alarm pheromone of most species studied is (E)-beta-farnesene. We recently demonstrated that the production and accumulation of (E)-beta-farnesene during development by juvenile aphids is stimulated by exposure to odor cues, most likely by (E)-beta-farnesene emitted by other colony members. Here, we tested whether the release of (E)-beta-farnesene can be triggered by exposure to the alarm pheromone of other individuals, thereby amplifying the signal. Such contagious emission might be adaptive under some conditions because the amount of (E)-beta-farnesene released by a single aphid may not be sufficient to alert an appropriate number of individuals of the colony to the presence of a potential threat. By using a push-pull headspace collection system, we quantified (E)-beta-farnesene released from Acyrthosiphon pisum aphids exposed to conspecific alarm signals. Typical avoidance behavior was observed following exposure to (E)-beta-farnesene (i.e., aphids ceased feeding and dropped from host-plant); however, no increase in alarm pheromone amount was detected, suggesting that contagious release of (E)-beta-farnesene does not occur. PMID:18704587

Verheggen, F J; Mescher, M C; Haubruge, E; Moraes, C M; Schwartzberg, E G

2008-08-14

275

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

PubMed

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. PMID:22772979

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

2013-03-01

276

Spread spectrum goes commercial  

Microsoft Academic Search

The use of spread-spectrum techniques to achieve more efficient utilization of available frequency spectra is examined. The two main spread-spectrum techniques, direct sequence and frequency hopping, are explained. In frequency hopping, the transmitter repeatedly changes (hops) the carrier frequency from one frequency to another. Direct-sequence transmission spreads the spectrum not by periodically changing the frequency but by modulating the original

D. L. Schilling; R. L. Pickholtz; L. B. Milstein

1990-01-01

277

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

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. PMID:21219754

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

2010-12-01

278

Parallelization: Infectious Disease  

NSDL National Science Digital Library

Epidemiology is the study of infectious disease. Infectious diseases are said to be "contagious" among people if they are transmittable from one person to another. Epidemiologists can use models to assist them in predicting the behavior of infectious diseases. This module will develop a simple agent-based infectious disease model, develop a parallel algorithm based on the model, provide a coded implementation for the algorithm, and explore the scaling of the coded implementation on high performance cluster resources.

Weeden, Aaron

279

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

ERIC Educational Resources Information Center

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

White, Michael D.; Klinger, David

2012-01-01

280

SPREAD OF A RUMOR  

Microsoft Academic Search

The spread of a rumor can be modeled as a classroom with n students and, on day one, a person is told a rumor. On day two, this person draws a number at random. If they draw their own number, the rumor is not spread and the process is repeated the next day. However, if they choose any number besides

NICK FEDEWA; ALEXANDRA SISSON; JAMES ANGELOS

281

Language-Spread Policy.  

ERIC Educational Resources Information Center

Language-spread policy (LSP) is policy promulgated by groups seeking to spread their languages to speakers or communicative domains. LSP can be internal or external, overt or disguised, and related in different ways to national policy. Intent may be to increase native-language advantage in international communication, disseminate ideology, create…

Ammon, Ulrich

1997-01-01

282

Host-induced epidemic spread of the cholera bacterium  

Microsoft Academic Search

The factors that enhance the transmission of pathogens during epidemic spread are ill defined. Water-borne spread of the diarrhoeal disease cholera occurs rapidly in nature, whereas infection of human volunteers with bacteria grown in vitro is difficult in the absence of stomach acid buffering. It is unclear, however, whether stomach acidity is a principal factor contributing to epidemic spread. Here

D. Scott Merrell; Susan M. Butler; Firdausi Qadri; Nadia A. Dolganov; Ahsfaqul Alam; Mitchell B. Cohen; Stephen B. Calderwood; Gary K. Schoolnik; Andrew Camilli

2002-01-01

283

Genotyping of Mycoplasma mycoides subsp. mycoides SC by multilocus sequence analysis allows molecular epidemiology of contagious bovine pleuropneumonia.  

PubMed

Mycoplasma mycoides subsp. mycoides SC (MmmSC) is the etiological agent of contagious bovine pleuropneumonia (CBPP). Although eradicated in most developed countries, the disease reappeared in Europe in the 1990s. This reappearance may have been caused either by importation from sub-Saharan Africa, where CBPP is still endemic, or by the reemergence of virulent strains in Europe, as suggested by earlier studies. A multilocus sequence analysis scheme has been developed to address this issue and, most importantly, to be able to monitor new epidemics. The alignment of the full genome sequence of the reference strain PG1 and the partial genome sequence of a pathogenic strain allowed the identification of polymorphic sites. Nineteen initial loci were selected within housekeeping genes, genes of unknown function and non coding sequences. The suitability of these loci for genotyping MmmSC strains was first tested on six strains of diverse geographic origin. The analyses showed that the published PG1 sequence contained a number of specific polymorphisms that were therefore of no use for molecular typing. Among the eight informative polymorphic loci finally selected, only one (ftsY) was positioned within a housekeeping gene. Three main groups and 31 different allelic profiles were identified among 51 strains and strain variants examined. Cluster analysis confirmed that European strains from the 1990s did not originate from Africa. It also showed a genetic link between a European strain isolated in 1967 and those found in southern Africa and Australia. This was in agreement with historical data showing that CBPP was introduced in these regions during colonisation in the 19th century. PMID:18258170

Yaya, Aboubakar; Manso-Silván, Lucía; Blanchard, Alain; Thiaucourt, François

2008-01-29

284

Infectious Diseases in Day Care.  

ERIC Educational Resources Information Center

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,…

Sleator, Esther K.

285

Foot-and-mouth disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

286

How the contagion at links influences epidemic spreading  

NASA Astrophysics Data System (ADS)

The reaction-diffusion (RD) model of epidemic spreading generally assume that contagion occurs only at the nodes of network, i.e., the links are used only for migration/diffusion of agents. However, in reality, we observe that contagion occurs also among the travelers staying in the same car, train or plane etc., which consist of the links of network. To reflect the contagious effect of links, we here present a traveling-contagion model where contagion occurs not only at nodes but also at links. Considering that the population density in transportation is generally much larger than that in districts, we introduce different infection rates for the nodes and links, respectively, whose two extreme cases correspond to the type-I and type-II reactions in the RD model [V. Colizza, R. Pastor-Satorras, A. Vespignani, Nat. Phys. 3, 276 (2007)]. Through studying three typical diffusion processes, we reveal both numerically and theoretically that the contagion at links can accelerate significantly the epidemic spreading. This finding is helpful in designing the controlling strategies of epidemic spreading.

Ruan, Zhongyuan; Tang, Ming; Liu, Zonghua

2013-04-01

287

Prevalence of contagious mastitis pathogens in bulk tank milk in Prince Edward Island  

PubMed Central

Abstract The purpose of this study was to 1) estimate the herd prevalence of contagious mastitis pathogens in bulk milk from Prince Edward Island (PEI) dairy farms, 2) determine the association between bulk milk culture results and mean bulk milk somatic cell count (BMSCC), and 3) investigate the agreement of repeated bulk milk cultures. Three consecutive bulk milk samples were obtained at weekly intervals from all 258 PEI dairy herds and were cultured using routine laboratory methods. Cumulative prevalence of Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp. (M. bovis and M. alkalescens) was 74%, 1.6%, and 1.9%, respectively. Bulk milk somatic cell count of Staph. aureus-positive herds was higher than that of negative herds. Agreement for Staph. aureus isolation between 3 consecutive tests was moderate (kappa = 0.46). Mycoplasma bovis and M. alkalescens in bulk milk are being reported for the 1st time in PEI ever and in Canada since 1972.

Barkema, Herman W.; Veenstra, Stefan; Poole, Doris E.; Dingwell, Randy T.; Keefe, Gregory P.

2006-01-01

288

Sea Floor Spreading I  

NSDL National Science Digital Library

In this introductory Excel tutorial (Activity I) students use Excel to explore the geodynamics model equation for ocean depth around a sea-floor spreading center. For students with no prior Excel experience.

Activity And Starting Point Page By R.m. Mackay. Clark College, Physics A.

289

9 CFR 71.3 - Interstate movement of diseased animals and poultry generally prohibited.  

Code of Federal Regulations, 2013 CFR

...following diseases, which are endemic to the United States: Equine piroplasmosis, bovine piroplasmosis or splenetic fever...pleuropneumonia, European fowl pest, dourine, contagious equine metritis, vesicular exanthema, screwworms and...

2013-01-01

290

The spreading of disorder.  

PubMed

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. PMID:19023045

Keizer, Kees; Lindenberg, Siegwart; Steg, Linda

2008-11-20

291

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

PubMed

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

Gjurasi?, Marija

2010-01-01

292

Technique for controlling spread of limnotic oncomelania  

NASA Astrophysics Data System (ADS)

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.

Li, Damei; Wang, Xiangsan; Lai, Yonggen

2003-09-01

293

Topography Driven Spreading  

NASA Astrophysics Data System (ADS)

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.

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

2004-07-01

294

Topography driven spreading.  

PubMed

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

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

2004-07-15

295

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

PubMed

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

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

2012-12-05

296

Disease awareness, information retrieval and change in biosecurity routines among pig farmers in association with the first PRRS outbreak in Sweden.  

PubMed

Reaching farmers with information is important when eradicating outbreaks of contagious diseases, the actions they take related to contacts and biosecurity, as well as early notification of disease can have a significant effect on limiting the spread of disease. The aim of this study was to investigate Swedish pig farmers' disease awareness, information retrieval and if they change their biosecurity routines during an outbreak of an exotic infectious disease, using the experience from the first outbreak of PRRS in Sweden in 2007. Data were collected through a questionnaire to 153 farmers. Our findings indicate that written information which was sent to all farmers was not sufficient. Herd size, as an indicator for the type of farmer, was significantly associated with awareness. Farmers with medium or large herds were more aware there had been an outbreak (OR 32.3, p=0.001), of the means of spread and the signs of disease, and they were more active in information search compared to farmers with small herds. Closeness to the outbreak was important for motivating farmers to actively search for information. The results from this study could be useful when planning information campaigns during future outbreaks and when modelling disease outbreaks. PMID:19376601

Nöremark, Maria; Lindberg, Ann; Vågsholm, Ivar; Sternberg Lewerin, Susanna

2009-04-18

297

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

PubMed

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

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

2013-08-28

298

Spread spectrum for commercial communications  

Microsoft Academic Search

The authors describe how spread spectrum operates and explain why the FCC has allocated several spectral bands for spread spectrum. They examine what is wrong with the spectrum allocations the way they are now. They show who is using and will use spread spectrum and why. In particular, they discuss the use of spread spectrum for mobile cellular communications: the

D. L. Schilling; L. B. Milstein; R. L. Pickholtz; M. Kullback; F. Miller

1991-01-01

299

Biosecurity: reducing disease risks to pig breeding herds  

Microsoft Academic Search

DISEASE imposes considerable constraints on the productivity and profitability of the livestock industry. Pig producers have probably suffered more than other sectors from the devastating effects of a succession of infectious disease outbreaks over the past 30 years. Many of these have been highly contagious viral diseases, including transmissible gastroenteritis (TGE), swine influenza (SI), Aujeszky's disease (AD), and porcine respiratory

Geoff Pritchard; Ian Dennis; Jake Waddilove

2005-01-01

300

Review Article: Current status of vaccines against infectious bursal disease  

Microsoft Academic Search

Infectious bursal disease virus (IBDV) is the aetiological agent of the acute and highly contagious infectious bursal disease (IBD) or “Gumboro disease”. IBD is one of the economically most important diseases that affects commercially produced chickens worldwide. Along with strict hygiene management of poultry farms, vaccination programs with inactivated and live attenuated viruses have been used to prevent IBD. Live

Hermann Müller; Egbert Mundt; Nicolas Eterradossi; M. Rafiqul Islam

2012-01-01

301

Current status of vaccines against infectious bursal disease  

Microsoft Academic Search

Infectious bursal disease virus (IBDV) is the aetiological agent of the acute and highly contagious infectious bursal disease (IBD) or “Gumboro disease”. IBD is one of the economically most important diseases that affects commercially produced chickens worldwide. Along with strict hygiene management of poultry farms, vaccination programmes with inactivated and live attenuated viruses have been used to prevent IBD. Live

Hermann Müller; Egbert Mundt; Nicolas Eterradossi; M. Rafiqul Islam

2012-01-01

302

25 CFR 166.310 - What must a permittee do to protect livestock from exposure to disease?  

Code of Federal Regulations, 2011 CFR

...permittees must: (a) Vaccinate livestock; (b) Treat all livestock exposed to or infected with contagious or infectious diseases; and (c) Restrict the movement of exposed or infected livestock. Management Plans and Environmental...

2011-04-01

303

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

PubMed

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

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

2012-10-01

304

[Studies of the origin of false positive reactions in the serodiagnosis of contagious bovine pleuropneumonia].  

PubMed

Four groups of cattle were experimentally immunised by four mycoplasma species of "mycoides-like" group, Mycoplasma (M) capricolum, M. mycoides subsp. mycoides (LC), M. mycoides subsp. capri and M. species group 7 of LEACH (PG50). They were then bled weekly during 2 months to establish antibodies kinetics against homologous and heterologous antigens. The standard method of complement fixation test (CFT) used in Europe and a new ELISA test for diagnosis of contagious bovine pleuropneumonia were performed in comparison with passive haemagglutination test (PHA) against antigens used for experimental immunisation. Cross reactions obtained are rather equal to the degree of similitude between these mycoplasma species. With CFT-cross reactions are transitory and occur only while homologous titers are very high, particularly with "PG50" and the two caprine mycoides strains. ELISA results using a threshold of positivity of optical density of 0.20, were similar to that obtained with CFT except ELISA specificity is not so different from CFT one. This experimental model could explain some natural situations. PMID:2485543

Poumarat, F; Perrin, M; Belli, P; Longchambon, D; Le Goff, C; Martel, J L

1989-01-01

305

A competitive ELISA for the specific diagnosis of contagious bovine pleuropneumonia (CBPP).  

PubMed

A competitive ELISA, using a specific monoclonal antibody, was designed to detect antibodies to Mycoplasma mycoides subsp. mycoides SC, the agent of contagious bovine pleuropneumonia. One monoclonal antibody was found suitable for such a test, '117/5', it does not cross-react with any of the other mycoplasma species tested, furthermore, its binding is inhibited by positive sera. The cutoff, 50% of inhibition, was determined using a set of negative sera from CBPP-free areas. The sensitivity was controlled with sera from artificially infected animals as well as from sera from areas where CBPP is enzootic. In both cases, cELISA compared favorably with CFT. The precocity of detection was similar but cELISA detected more positives and the positive titers seemed to persist longer than in the case of CFT. Lysis of the antigen used to coat the ELISA plates reduced the variability of fixation and improved the repeatability of the test. A field evaluation is now in progress which will determine the true sensitivity and specificity of the test and also check if antibodies are detected after vaccination. PMID:9646449

Le Goff, C; Thiaucourt, F

1998-02-28

306

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

PubMed

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. PMID:16417927

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

2006-01-18

307

FIRE SPREAD IN CHAPARRAL - \\  

Microsoft Academic Search

Current fire models are designed to model the spread of a linear fire front in dead, small-diameter fuels. Fires in predominantly living vegetation account for a large proportion of annual burned area nationally. Prescribed burning is used to manage living fuels; however, prescribed burning is currently conducted under conditions that result in marginal burning. We do not quantitatively understand the

David R. Weise; Xiangyang Zhou; Lulu Sun; Shankar Mahalingam

308

Information spreading in context  

Microsoft Academic Search

Information spreading processes are central to human interactions. Despite recent studies in online domains, little is known about factors that could affect the dissemination of a single piece of information. In this paper, we address this challenge by combining two related but distinct datasets, collected from a large scale privacy-preserving distributed social sensor system. We find that the social and

Dashun Wang; Zhen Wen; Hanghang Tong; Ching-Yung Lin; Chaoming Song; Albert-László Barabási

2011-01-01

309

Spreading the silence.  

PubMed

RITS (RNA-induced initiation of transcriptional gene silencing complex) plays diverse roles in heterochromatin regulation: silencing transcription by recruitment of chromatin modifiers and destroying transcripts by RNAi. In a recent issue of Molecular Cell, Li et al. now show that the polymerization of Tas3, a component of RITS, contributes to the spreading of silencing mediated by RITS. PMID:19460340

Partridge, Janet F

2009-05-01

310

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

PubMed

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. PMID:23670215

Buttner, Alicia Phillips; Strasser, Rosemary

2013-05-14

311

Infectious disease modeling of social contagion in networks.  

PubMed

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

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

2010-11-04

312

Infectious Disease Modeling of Social Contagion in Networks  

PubMed Central

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

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

2010-01-01

313

TREATMENT THRESHOLDS FOR THE GLASSY-WINGED SHARPSHOOTER BASED ON THE LOCAL EPIDEMIOLOGY OF PIERCE'S DISEASE SPREAD (A STAGE-STRUCTURED EPIDEMIC MODEL) Project Leader  

Microsoft Academic Search

The conditions for the successful invasion of a vineyard by Pierce's disease (PD) are not well understood. To help integrate what knowledge we do have and indicate areas where research is needed we are developing a more biologically detailed model than has been previously available. Fortunately there is a large ensemble of literature from epidemiology regarding this problem, and in

Thomas M. Perring; Jon C. Allen; Charles A. Farrar; Rayda K. Krell

314

Wartime evacuation and the spread of infectious diseases: epidemiological consequences of the dispersal of children from London during World War II  

Microsoft Academic Search

The proposal to evacuate children from the large towns and cities of the United Kingdom during World War II caused much concern among wartime epidemiologists and public health officials. It was anticipated that dispersal on such an unprecedented scale might result in an unusually high incidence of epidemic disease amongst the native children of the reception areas. Although studies were

Matthew Smallman-Raynor; Cathryn Nettleton; Andrew Cliff

2003-01-01

315

Human H3N2 Influenza Viruses Isolated from 1968 To 2012 Show Varying Preference for Receptor Substructures with No Apparent Consequences for Disease or Spread  

PubMed Central

It is generally accepted that human influenza viruses bind glycans containing sialic acid linked ?2–6 to the next sugar, that avian influenza viruses bind glycans containing the ?2–3 linkage, and that mutations that change the binding specificity might change the host tropism. We noted that human H3N2 viruses showed dramatic differences in their binding specificity, and so we embarked on a study of representative human H3N2 influenza viruses, isolated from 1968 to 2012, that had been isolated and minimally passaged only in mammalian cells, never in eggs. The 45 viruses were grown in MDCK cells, purified, fluorescently labeled and screened on the Consortium for Functional Glycomics Glycan Array. Viruses isolated in the same season have similar binding specificity profiles but the profiles show marked year-to-year variation. None of the 610 glycans on the array (166 sialylated glycans) bound to all viruses; the closest was Neu5Ac?2–6(Gal?1–4GlcNAc)3 in either a linear or biantennary form, that bound 42 of the 45 viruses. The earliest human H3N2 viruses preferentially bound short, branched sialylated glycans while recent viruses bind better to long polylactosamine chains terminating in sialic acid. Viruses isolated in 1996, 2006, 2010 and 2012 bind glycans with ?2–3 linked sialic acid; for 2006, 2010 and 2012 viruses this binding was inhibited by oseltamivir, indicating binding of ?2–3 sialylated glycans by neuraminidase. More significantly, oseltamivir inhibited virus entry of 2010 and 2012 viruses into MDCK cells. All of these viruses were representative of epidemic strains that spread around the world, so all could infect and transmit between humans with high efficiency. We conclude that the year-to-year variation in receptor binding specificity is a consequence of amino acid sequence changes driven by antigenic drift, and that viruses with quite different binding specificity and avidity are equally fit to infect and transmit in the human population.

Gulati, Shelly; Smith, David F.; Cummings, Richard D.; Couch, Robert B.; Griesemer, Sara B.; St. George, Kirsten; Webster, Robert G.; Air, Gillian M.

2013-01-01

316

Epidemics spreading in predator–prey systems  

Microsoft Academic Search

In this paper, we consider an ecosystem in which two disease-affected populations thrive and in which the epidemics can spread from one species to the other one by contact. The feasibility and stability conditions of the equilibria of the system are investigated analytically. The model does not possess Hopf bifurcations. Numerical simulations are performed to investigate the role of the

S. Chaudhuri; A. Costamagna; E. Venturino

2012-01-01

317

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

PubMed

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

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

2013-04-16

318

Margarines and Spreads  

Microsoft Academic Search

The application margarine and spreads refers to a series of products, which are likened to butter, but have different fat\\u000a contents. The definition of margarine is rigidly fixed with regards to fat content, a minimum of 80% by weight must be present,\\u000a but the rheological characteristics of margarine can range from liquid to plastic in nature. Any edible oil or

Niall Young; Paul Wassell

319

Traveling Dynamics and Epidemic Spreading on the Aviation Network  

NASA Astrophysics Data System (ADS)

The rapid worldwide spread of SARS demonstrated the potential threat an infectious disease poses in a closely interconnected and interdependent world. What can be done in a global community to prevent and control future epidemics? Here we introduce a novel probabilistic model which describes the worldwide spreading of infectious diseases and demonstrate that a forecast of the geographical spread of epidemics is indeed possible. It combines a local infection dynamics between individuals with stochastic transport in a worldwide network which takes into account the civil aviation traffic. Our simulations of the SARS outbreak are in good agreement with the case reports published by the World Health Organization. Our model can be used to predict the worldwide spreading of future infectious diseases and to identify endangered regions in advance. We find that the pattern of the epidemic spread is strongly affected by the location of the initial infection. The performance of different control strategies is analysed.

Hufnagel, Lars; Brockmann, Dirk; Geisel, Theo

2004-03-01

320

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

321

Cow's Milk and Human Disease Bovine Tuberculosis and the Difficulties Involved in Combating Animal Diseases  

Microsoft Academic Search

In dealing with the incidence and impact of animal diseases on humans, particular attention is always devoted to the etiology. Whether, and how, a contagious disease is transmitted from animals to humans (and vice versa) is the most often highlighted question, because much hope rests on the idea that the search for and identifying of a pathogen and how this

Barbara Orland

322

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

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.

Madsen, Elainie Alenkaer; Persson, Tomas; Sayehli, Susan; Lenninger, Sara; Sonesson, Goran

2013-01-01

323

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

PubMed

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

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

2013-10-16

324

Hybrid spread spectrum radio system  

DOEpatents

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.

Smith, Stephen F. (London, TN); Dress, William B. (Camas, WA)

2010-02-09

325

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

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. PMID:21875453

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

2011-08-30

326

The Galapagos Spreading Center  

NSDL National Science Digital Library

In this lesson, with a focus on mid-ocean ridges, students will discover how new ocean floor is formed. They will study the processes involved in creating new seafloor at a mid-ocean ridge, investigate the Galapagos Spreading Center system, and understand the different types of plate motion associated with ridge segments and transform faults. This hands-on activity uses online data resources and includes: focus questions, learning objectives, teaching time, audio/visual materials needed, background information, learning procedures, evaluations, extensions, as well as resources and student handouts.

327

The Spread of Inequality  

PubMed Central

The causes of socioeconomic inequality have been debated since the time of Plato. Many reasons for the development of stratification have been proposed, from the need for hierarchical control over large-scale irrigation systems to the accumulation of small differences in wealth over time via inheritance processes. However, none of these explains how unequal societies came to completely displace egalitarian cultural norms over time. Our study models demographic consequences associated with the unequal distribution of resources in stratified societies. Agent-based simulation results show that in constant environments, unequal access to resources can be demographically destabilizing, resulting in the outward migration and spread of such societies even when population size is relatively small. In variable environments, stratified societies spread more and are also better able to survive resource shortages by sequestering mortality in the lower classes. The predictions of our simulation are provided modest support by a range of existing empirical studies. In short, the fact that stratified societies today vastly outnumber egalitarian societies may not be due to the transformation of egalitarian norms and structures, but may instead reflect the more rapid migration of stratified societies and consequent conquest or displacement of egalitarian societies over time.

Rogers, Deborah S.; Deshpande, Omkar; Feldman, Marcus W.

2011-01-01

328

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

PubMed

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. PMID:22387223

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

2012-03-02

329

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

PubMed Central

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

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

2009-01-01

330

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

PubMed Central

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 .

Novossiolova, Tatyana; Minehata, Masamichi; Dando, Malcolm

2012-01-01

331

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

PubMed

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

Novossiolova, Tatyana; Minehata, Masamichi; Dando, Malcolm

2012-01-01

332

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

PubMed

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. PMID:7925674

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

1994-10-01

333

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

PubMed Central

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

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

1994-01-01

334

Innovation spread: lessons from HIV.  

PubMed

Efficient spreading of evidence-based innovations among complex health systems remains an elusive goal despite extensive study in the social sciences. Biology provides a model of successful spread in viruses, which have evolved to spread with maximum efficiency using minimal resources. Here we explore the molecular mechanisms of human immunodeficiency virus (HIV) spread and identify five steps that are also common to a recent example of spread in complex health systems: reduction in door-to-balloon times for patients with ST-segment elevation myocardial infarction (STEMI). We then describe a new model we have developed, called AIDED, which is based on mixed-methods research but informed by the conceptual framework of HIV spread among cells. The AIDED model contains five components: Assess, Innovate, Develop, Engage and Devolve, and can describe any one of the following: the spread of HIV among cells, the spread of practices to reduce door-to-balloon time for patients with STEMI and the spread of certain family health innovations in low- and middle-income countries. We suggest that by looking to the biological sciences for a model of spread that has been honed by evolution, we may have identified fundamental steps that are necessary and sufficient for efficient, low-cost spread of health innovations among complex health systems. PMID:23696582

Talbert-Slagle, Kristina; Berg, David; Bradley, Elizabeth H

2013-05-21

335

Review of Newcastle disease virus with particular references to immunity and vaccination  

Microsoft Academic Search

Newcastle disease (ND) is a highly contagious disease. The present paper deals with classification of ND virus (NDV), clinical signs and pathology, virus strain classification and molecular backgrounds for the pathogenicity. Major emphasis is reviewing immunity and vaccination. Clinical forms of the disease vary depending on many factors, but mainly on the virulence of Newcastle disease virus (NDV) strains. Virulent

S. O. Al-Garib; A. L. J. Gielkens; E. Gruys; G. Koch

2003-01-01

336

MAREK'S DISEASE VIRUS GENE LORF11 DELETION MUTANT IS ESSENTIAL FOR REPLICATION IN CHICKENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Marek's disease virus (MDV) is an oncogenic herpesvirus, which causes a highly contagious neoplastic disease in chickens, Marek's disease. The disease is characterized by the development of T-cell lymphomas, neurological disorders and immune-deficiency, and for some strains, atherosclerosis. This d...

337

Genome-wide identification of host genes directly regulated by Marek's disease virus (MDV) oncoprotein Meq  

Technology Transfer Automated Retrieval System (TEKTRAN)

Marek's disease (MD) is a contagious lymphoproliferative and neurotropic disease of poultry caused by the Marek's disease virus (MDV), an oncogenic alphaherpesvirus. Despite the use of vaccines, field strains of MDV continue to evolve resulting in unpredictable disease outbreaks. Therefore, understa...

338

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

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Control of livestock disease and introduction...REGULATIONS § 167.15 Control of livestock disease and introduction...safeguard Indian livestock from infections and contagious disease and...disease conditions beyond the control measures provided herein...

2013-04-01

339

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

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Control of livestock disease and introduction...REGULATIONS § 167.15 Control of livestock disease and introduction...safeguard Indian livestock from infections and contagious disease and...disease conditions beyond the control measures provided herein...

2011-04-01

340

The skin ulceration disease in cultivated juveniles of Holothuria scabra (Holothuroidea, Echinodermata)  

Microsoft Academic Search

It is frequently reported that cultivated holothuroids can suffer from a disease affecting their integument. We report here on a disease of juvenile Holothuria scabra, the widely marketed edible sea cucumber, reared in the Aqua-Lab hatchery of Toliara, Madagascar. This disease, which has been called skin ulceration disease, is very contagious and results from a severe bacterial infection that causes

P. Becker; D. Gillan; D. Lanterbecq; M. Jangoux; R. Rasolofonirina; J. Rakotovao; I. Eeckhaut

2004-01-01

341

A PCR for the detection of mycoplasmas belonging to the Mycoplasma mycoides cluster: application to the diagnosis of contagious agalactia.  

PubMed

Contagious agalactia is a mycoplasmal infection caused by Mycoplasma agalactiae, Mycoplasma mycoides subsp. mycoides LC, M. mycoides subsp. capri, Mycoplasma capricolum subsp. capricolum and Mycoplasma putrefaciens. Identification of the causative organisms is usually performed by isolation and classical biochemical and serological tests, though this is a lengthy and cumbersome process for mycoplasmas. Specific PCR assays have been developed for the identification of Mycoplasma agalactiae and M. putrefaciens. For members of the M. mycoides cluster existing PCR tests are based on the amplification of highly conserved genes coding for ribosomal proteins, hence a possibility of cross-reactions. The gene glk, coding for a glucokinase, that is found in this cluster is very distantly related to any other bacterial glucokinase described so far. It was therefore chosen as target to design a new PCR test. The validation was performed independently in three laboratories in France and India using over 100 mycoplasma strains of various geographical origins. All strains belonging to the M. mycoides cluster were detected by amplification of the expected PCR product (428 bp) while no amplification was obtained from M. agalactiae strains. Our results demonstrate the universality of this PCR in spite of the great heterogeneity found within this cluster. This new tool may be of great help for the implementation of control measures directed towards contagious agalactia. PMID:17606362

Woubit, S; Manso-Silván, L; Lorenzon, S; Gaurivaud, P; Poumarat, F; Pellet, M-P; Singh, V P; Thiaucourt, F

2007-06-07

342

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

PubMed Central

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.

Dolz, Roser; Valle, Rosa; Perera, Carmen L.; Bertran, Kateri; Frias, Maria T.; Majo, Natalia; Ganges, Llilianne; Perez, Lester J.

2013-01-01

343

Spreading convulsions, spreading depolarization and epileptogenesis in human cerebral cortex  

PubMed Central

Spreading depolarization of cells in cerebral grey matter is characterized by massive ion translocation, neuronal swelling and large changes in direct current-coupled voltage recording. The near-complete sustained depolarization above the inactivation threshold for action potential generating channels initiates spreading depression of brain activity. In contrast, epileptic seizures show modest ion translocation and sustained depolarization below the inactivation threshold for action potential generating channels. Such modest sustained depolarization allows synchronous, highly frequent neuronal firing; ictal epileptic field potentials being its electrocorticographic and epileptic seizure its clinical correlate. Nevertheless, Leão in 1944 and Van Harreveld and Stamm in 1953 described in animals that silencing of brain activity induced by spreading depolarization changed during minimal electrical stimulations. Eventually, epileptic field potentials were recorded during the period that had originally seen spreading depression of activity. Such spreading convulsions are characterized by epileptic field potentials on the final shoulder of the large slow potential change of spreading depolarization. We here report on such spreading convulsions in monopolar subdural recordings in 2 of 25 consecutive aneurismal subarachnoid haemorrhage patients in vivo and neocortical slices from 12 patients with intractable temporal lobe epilepsy in vitro. The in vitro results suggest that ?-aminobutyric acid-mediated inhibition protects from spreading convulsions. Moreover, we describe arterial pulse artefacts mimicking epileptic field potentials in three patients with subarachnoid haemorrhage that ride on the slow potential peak. Twenty-one of the 25 subarachnoid haemorrhage patients (84%) had 656 spreading depolarizations in contrast to only three patients (12%) with 55 ictal epileptic events isolated from spreading depolarizations. Spreading depolarization frequency and depression periods per 24?h recording episodes showed an early and a delayed peak on Day 7. Patients surviving subarachnoid haemorrhage with poor outcome at 6 months showed significantly higher total and peak numbers of spreading depolarizations and significantly longer total and peak depression periods during the electrocorticographic monitoring than patients with good outcome. In a semi-structured telephone interview 3 years after the initial haemorrhage, 44% of the subarachnoid haemorrhage survivors had developed late post-haemorrhagic seizures requiring anti-convulsant medication. In those patients, peak spreading depolarization number had been significantly higher [15.1 (11.4–30.8) versus 7.0 (0.8–11.2) events per day, P?=?0.045]. In summary, monopolar recordings here provided unequivocal evidence of spreading convulsions in patients. Hence, practically all major pathological cortical network events in animals have now been observed in people. Early spreading depolarizations may indicate a risk for late post-haemorrhagic seizures.

Major, Sebastian; Pannek, Heinz-Wolfgang; Woitzik, Johannes; Scheel, Michael; Wiesenthal, Dirk; Martus, Peter; Winkler, Maren K.L.; Hartings, Jed A.; Fabricius, Martin; Speckmann, Erwin-Josef; Gorji, Ali

2012-01-01

344

The Geomorphology of Spread F  

Microsoft Academic Search

An analysis has been made of reliable spread-F data obtained from IGY f plots for ionosonde stations grouped about longitudes 75øW and 120øE. The temporal variations of occurrence of the frequency-spreading component of spread F are found to change with lati- tude, these changes having a certain symmetry about the geomagnetic equator rather than about the geographic or dip equators.

D. G. Singleton

1960-01-01

345

Did ice-age bovids spread tuberculosis?  

NASA Astrophysics Data System (ADS)

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.

Rothschild, Bruce M.; Martin, Larry D.

2006-11-01

346

Did ice-age bovids spread tuberculosis?  

PubMed

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. PMID:16896974

Rothschild, Bruce M; Martin, Larry D

2006-08-04

347

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

Code of Federal Regulations, 2010 CFR

... 2 2009-01-01 2009-01-01 false Ham spread, tongue spread, and similar products. 319.762 Section 319...OF IDENTITY OR COMPOSITION Meat Salads and Meat Spreads § 319.762 Ham spread, tongue spread, and...

2009-01-01

348

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

Code of Federal Regulations, 2010 CFR

... 2 2010-01-01 2010-01-01 false Ham spread, tongue spread, and similar products. 319.762 Section 319...OF IDENTITY OR COMPOSITION Meat Salads and Meat Spreads § 319.762 Ham spread, tongue spread, and...

2010-01-01

349

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

Code of Federal Regulations, 2013 CFR

...spread, tongue spread, and similar products. 319.762 Section 319.762 Animals and Animal Products FOOD SAFETY AND INSPECTION...COMPOSITION Meat Salads and Meat Spreads § 319.762 Ham spread, tongue spread, and similar...

2013-01-01

350

The small world yields the most effective information spreading  

NASA Astrophysics Data System (ADS)

The spreading dynamics of information and diseases are usually analyzed by using a unified framework and analogous models. In this paper, we propose a model to emphasize the essential difference between information spreading and epidemic spreading, where the memory effects, the social reinforcement and the non-redundancy of contacts are taken into account. Under certain conditions, the information spreads faster and broader in regular networks than in random networks, which to some extent supports the recent experimental observation of spreading in online society (Centola D 2010 Science 329 1194). At the same time, the simulation result indicates that the random networks tend to be favorable for effective spreading when the network size increases. This challenges the validity of the above-mentioned experiment for large-scale systems. More importantly, we show that the spreading effectiveness can be sharply enhanced by introducing a little randomness into the regular structure, namely the small-world networks yield the most effective information spreading. This work provides insights into the role of local clustering in information spreading.

Lü, Linyuan; Chen, Duan-Bing; Zhou, Tao

2011-12-01

351

MRSA virulence and spread  

PubMed Central

Summary Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most frequent causes of hospital- and community-associated infections. Resistance to the entire class of ?-lactam antibiotics, such as methicillin and penicillin, makes MRSA infections difficult to treat. Hospital-associated MRSA strains are often multi-drug resistant, leaving only lower efficiency drugs such as vancomycin as treatments options. Like many other S. aureus strains, MRSA strains produce a series of virulence factors, such as toxins and adhesion proteins. Recent findings have shed some new light on the molecular events that underlie MRSA epidemic waves. Newly emerging MRSA clones appear to have acquired phenotypic traits that render them more virulent or able to colonize better, either via mobile genetic elements or adaptation of gene expression. Acquisition of Panton-Valentine leukocidin genes and increased expression of core genome-encoded toxins are being discussed as potentially contributing to the success of the recently emerged community-associated MRSA strains. However, the molecular factors underlying the spread of hospital- and community-associated MRSA strains are still far from being completely understood, a situation calling for enhanced research efforts in that area.

Otto, Michael

2012-01-01

352

Islamic Universities Spread through Africa  

ERIC Educational Resources Information Center

|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…

Lindow, Megan

2007-01-01

353

Increased Spreading Activation in Depression  

ERIC Educational Resources Information Center

|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…

Foster, Paul S.; Yung, Raegan C.; Branch, Kaylei K.; Stringer, Kristi; Ferguson, Brad J.; Sullivan, William; Drago, Valeria

2011-01-01

354

Increased Spreading Activation in Depression  

ERIC Educational Resources Information Center

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…

Foster, Paul S.; Yung, Raegan C.; Branch, Kaylei K.; Stringer, Kristi; Ferguson, Brad J.; Sullivan, William; Drago, Valeria

2011-01-01

355

Pricing and Hedging Spread Options  

Microsoft Academic Search

We survey the theoretical and the computational problems associated with the pricing of spread options. These options are ubiquitous in the financial markets, whether they be equity, fixed income, foreign exchange, commodities, or energy markets. As a matter of introduction, we present a general overview of the common features of all the spread options by discussing in detail their roles

Rene Carmona; Valdo Durrleman

2003-01-01

356

Analytic Approximations for Spread Options  

Microsoft Academic Search

This paper expresses the price of a spread option as the sum of the prices of two compound options. One compound option is to exchange vanilla call options on the two underlying assets and the other is to exchange the corresponding put options. This way we derive a new analytic approximation for the price of a European spread option, and

Carol Alexander; Aanand Venkatramanan

2007-01-01

357

Cervical lymph node metastasis in oral cancer: the importance of even microscopic extracapsular spread  

Microsoft Academic Search

The prognostic significance of extracapsular spread of cervical metastases in oral cancer is still controversial. To investigate the importance of extent of extracapsular spread; the relationship between extracapsular spread and both traditional measures of metastatic disease and clinical\\/histological features of the primary tumour, and to determine their relative prognostic significance. The survival of 173 patients undergoing radical surgery and simultaneous

J. A. Woolgar; S. N. Rogers; D. Lowe; J. S. Brown; E. D. Vaughan

2003-01-01

358

25 CFR 168.15 - Control of livestock diseases and parasites.  

Code of Federal Regulations, 2010 CFR

...false Control of livestock diseases and parasites. 168.15 Section 168.15 Indians...15 Control of livestock diseases and parasites. Whenever livestock within the Hopi...with contagious or infectious diseases or parasites or have been exposed thereto, such...

2010-04-01

359

25 CFR 700.723 - Control of livestock disease and parasites.  

Code of Federal Regulations, 2010 CFR

...false Control of livestock disease and parasites. 700.723 Section 700.723 Indians...723 Control of livestock disease and parasites. Whenever livestock within the New...with contagious or infectious disease or parasites or have been exposed thereto, such...

2009-04-01

360

25 CFR 700.723 - Control of livestock disease and parasites.  

Code of Federal Regulations, 2010 CFR

...false Control of livestock disease and parasites. 700.723 Section 700.723 Indians...723 Control of livestock disease and parasites. Whenever livestock within the New...with contagious or infectious disease or parasites or have been exposed thereto, such...

2010-04-01

361

25 CFR 168.15 - Control of livestock diseases and parasites.  

Code of Federal Regulations, 2010 CFR

...false Control of livestock diseases and parasites. 168.15 Section 168.15 Indians...15 Control of livestock diseases and parasites. Whenever livestock within the Hopi...with contagious or infectious diseases or parasites or have been exposed thereto, such...

2009-04-01

362

Authorisation within the European Union of vaccines against antigenically variable viruses responsible for major epizootic diseases  

Microsoft Academic Search

Summary Antigenically variable viruses are responsible for some of the most contagious and economically important diseases that affect domestic livestock. The serious consequences of such diseases in terms of economic loss, and human and animal health, were clearly demonstrated by recent epizootics of foot and mouth disease, and outbreaks of avian influenza and bluetongue in the European Union (EU). For

D. K. J. Mackay

2007-01-01

363

Genetics and Vaccine Efficacy: Host Genetic Variation Affecting Marek's Disease Vaccine Efficacy in White Leghorn Chickens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Marek’s disease (MD) is a T cell lymphoma disease of domestic chickens induced by Marek’s disease viruses (MDV), a naturally oncogenic and highly contagious cell-associated alpha-herpesvirus. Earlier reports have shown that the major histocompatibility complex (MHC) haplotype as well as non-MHC gene...

364

Foot & Mouth Disease & Ulcerative\\/Vesicular Rule-outs: Challenges Encountered in Recent Outbreaks  

Microsoft Academic Search

Foot and mouth disease (FMD) is a highly infectious and contagious viral disease affecting bovidae (cattle, zebus, domestic buffaloes, yaks), sheep, goats, swine, all wild ruminants and suidae. Camelidae (camels, dromedaries, llamas, vicunas) have low susceptibility. Foot and mouth disease is caused by a RNS virus of the family Picornaviridae, genus Aphthovirus. There are seven immunologically distinct serotypes: A, O,

Hullinger

2008-01-01

365

Detection of Mycoplasma mycoides subspecies mycoides in tissues from an outbreak of contagious bovine pleuropneumonia by culture, immunohistochemistry and polymerase chain reaction  

Microsoft Academic Search

Postmortem observations of 37 cattle from an outbreak of contagious bovine pleuropneumonia (CBPP) in north Italy in 1993 were made at the abattoir, where samples of lung and tracheobronchial lymph node tissues were taken for culture and identification of Mycoplasma mycoides subspedes mycoides (MmmSC), immunohistochemistry with the peroxidase anti-peroxidase (PAP) system, and molecular detection by the polymerase chain reaction (KR)

J. B. Bashiruddin; F. G. Santini; P. De Santis; M. C. Visaggio; G. Di Francesco; A. DAngelo; R. A. J. Nicholas

1999-01-01

366

Intramammary infections with the contagious Staphylococcus aureus genotype B in Swiss dairy cows are associated with low prevalence of coagulase-negative staphylococci and Streptococcus spp  

Microsoft Academic Search

The association between the contagious Staphylococcus aureus genotype B (GTB) and the presence of coagulase-negative staphylococci (CNS) and Streptococcus spp. (non-agalactiae streptococci), was investigated, and the identification of problem herds without genotyping was evaluated. Milk samples from 10 herds with Staph. aureus GTB herd problems (PH cases) were compared with samples from 19 herds with at least one Staph. aureus

Astrid Michel; Claudia Syring; Adrian Steiner; Hans U. Graber

2011-01-01

367

Characterization of Strains of Mycoplasma mycoides subsp. mycoides Small Colony Type Isolated from Recent Outbreaks of Contagious Bovine Pleuropneumonia in Botswana and Tanzania: Evidence for a New Biotype  

Microsoft Academic Search

Four strains of Mycoplasma mycoides subsp. mycoides small colony type (MmmSC) isolated from recent outbreaks of contagious bovine pleuropneumonia (CBPP) in Africa have been investigated. One Botswanan strain, M375, displayed numerous and significant phenotypic differences from both contemporary field isolates and older field and vaccine strains (African, Australian, and European strains dating back to 1936). Differ- ences include altered morphology,

JOHN B. MARCH; JASON CLARK; MALCOLM BRODLIE

2000-01-01

368

Contagious Itch in Humans. A Study of Visual "Transmission" of Itch in Atopic Dermatitis and Healthy Subjects  

PubMed Central

Anecdotal evidence suggests “contagious” itch occurs in daily life when we see other people itch and scratch. This phenomenon has not been systematically studied previously, and factors which can amplify itch perception were unknown. We investigated whether exposure to visual cues of itch can induce or intensify itch in healthy and atopic dermatitis subjects. Participants received histamine or a saline control delivered to the forearm and were asked to watch short video clips of people scratching. Spontaneous scratching induced by visual cues was monitored and analyzed. Atopic dermatitis patients reported a higher itch intensity and scratched more frequently while watching itch videos, even in the presence of mock itch stimuli. Human susceptibility to develop itch when exposed to visual cues is confirmed and it appears amplified in atopic dermatitis sufferers. These findings suggest that interpersonal social cues can dramatically alter the subjective sensory experience of itch.

Papoiu, A.D.P.; Wang, H.; Coghill, R.C.; Chan, Y-H.; Yosipovitch, G.

2011-01-01

369

Lyme Disease  

MedlinePLUS

... on the Pacific Coast). These ticks can spread the disease to animals and humans through tick bites. These ticks are typically about the size of a sesame seed. Lyme disease is most common in rural and suburban areas ...

370

[Interhospital spread of Shigella flexneri 2A].  

PubMed

In this article the results of the study of regularities in the development of outbreak morbidity in shigellosis, caused by S.flexneri 2a, in hospitals are presented. The study was carried out with the use of the method of typing by the plasmid profile. The study showed the continuity of the epidemic process in the foci which appeared at intervals considerably exceeding the incubation period. The fact of the interhospital spread of S.flexneri 2a was established. The strain causing the disease was identified by the characteristic set of plasmids and their size. The possibility of reinfection of patients with S.flexneri 2a under hospital conditions was confirmed. The possibility of changes in the main transmission routes in the course of the spread of S.flexneri 2a infection in closed groups was pointed out. PMID:9700878

Kurakin, E S

371

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

G197del is the most prevalent LDL receptor (LDLR) mutation causing familial hypercholesterolemia (FH) in Ashkenazi Jew (AJ) individuals. The purpose of this study was to determine the origin, age, and population distribution of G197del, as well as to explore environmental and genetic effects on disease expression. Index cases from Israel (n=46), South Africa (n=24), Russia (n=7), The Netherlands (n=1), and the United States (n=1) were enlisted. All trace their ancestry to Lithuania. A highly conserved haplotype (D19S221:104-D19S865:208-D19S413:74) was identified in G197del chromosomes, suggesting the occurrence of a common founder. When two methods were used for analysis of linkage disequilibrium (LD) between flanking polymorphic markers and the disease locus and for the study of the decay of LD over time, the estimated age of the deletion was found to be 20 ± 7 generations (the 95% confidence interval is 15–26 generations), so that the most recent common ancestor of the mutation-bearing chromosomes would date to the 14th century. This corresponds with the founding of the Jewish community of Lithuania (1338 a.d.), as well as with the great demographic expansion of AJ individuals in eastern Europe, which followed this settlement. The penetrance of mutation-linked severe hypercholesterolemia is high (94% of heterozygotes have a baseline concentration of LDL cholesterol (LDL-C) that is >160 mg/dl), and no significant differences in the mean baseline lipid level of G197del carriers from different countries were found. Polymorphisms of apolipoprotein E and of scavenger-receptor class B type I were observed to have minor effects on the plasma lipid profile. With respect to determinative genetic influences on the biochemical phenotype, there is no evidence that could support the possibility of a selective evolutionary metabolic advantage. Therefore, the founder effect in a rapidly expanding population from a limited number of families remains a simple, parsimonious hypothesis explaining the spread of G197del-LDLR–linked FH in AJ individuals.

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

372

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

PubMed

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. PMID:23076724

Madsen, Elainie Alenkær; Persson, Tomas

2012-10-18

373

Biological characterization and phylogenetic analysis of a novel genetic group of Newcastle disease virus isolated from outbreaks in commercial poultry and from backyard poultry flocks in Pakistan.  

PubMed

Newcastle disease (ND) is a contagious viral disease of many avian species particularly domestic poultry, and is responsible for devastating outbreaks in the poultry industries around the globe. In spite of its importance and endemicity in Southern Asia, data on the genetic nature of the viruses and epizootiological information of the disease is scarce. In this study, six isolates from an emerging wave of ND outbreaks in the north of Pakistan and two isolates from healthy poultry flocks were biologically and genetically characterized. Based on pathogenicity indices such as intracerebral pathogenicity index (ICPI), mean death time (MDT) and cleavage motifs in the fusion protein, all these isolates were classified as virulent. Phylogenetic analysis of the fusion (F), hemagglutinin-neuraminidase (HN) and matrix (M) genes indicated the emergence of a novel genetic group within lineage 5, distinct from isolates previously reported in the region. Several mutations in the neutralizing epitopes and functionally important motifs of the F and HN genes pose a need for re-evaluation of the currently used vaccine and vaccination practices. The characteristics of Newcastle disease virus (NDV) as virulent (F protein cleavage site, ICPI and MDT) in apparently healthy backyard poultry (BYP) explain that BYP can play crucial role in the epizootiology and spread of the disease. The present investigation provides essential information on the genetic nature of NDV circulating in Pakistan and its implication on disease diagnosis and control. Furthermore, these investigations emphasize the importance of continuous surveillance of ND in developing countries. PMID:22418457

Munir, Muhammad; Cortey, Martí; Abbas, Muhammad; Qureshi, Zafar Ul Ahsan; Afzal, Farhan; Shabbir, Muhammad Zubair; Khan, Muhammad Tanveer; Ahmed, Safia; Ahmad, Saeed; Baule, Claudia; Ståhl, Karl; Zohari, Siamak; Berg, Mikael

2012-03-06

374

Spreading gossip in social networks.  

PubMed

We study a simple model of information propagation in social networks, where two quantities are introduced: the spread factor, which measures the average maximal reachability of the neighbors of a given node that interchange information among each other, and the spreading time needed for the information to reach such a fraction of nodes. When the information refers to a particular node at which both quantities are measured, the model can be taken as a model for gossip propagation. In this context, we apply the model to real empirical networks of social acquaintances and compare the underlying spreading dynamics with different types of scale-free and small-world networks. We find that the number of friendship connections strongly influences the probability of being gossiped. Finally, we discuss how the spread factor is able to be applied to other situations. PMID:17930316

Lind, Pedro G; da Silva, Luciano R; Andrade, José S; Herrmann, Hans J

2007-09-27

375

Spreading gossip in social networks  

NASA Astrophysics Data System (ADS)

We study a simple model of information propagation in social networks, where two quantities are introduced: the spread factor, which measures the average maximal reachability of the neighbors of a given node that interchange information among each other, and the spreading time needed for the information to reach such a fraction of nodes. When the information refers to a particular node at which both quantities are measured, the model can be taken as a model for gossip propagation. In this context, we apply the model to real empirical networks of social acquaintances and compare the underlying spreading dynamics with different types of scale-free and small-world networks. We find that the number of friendship connections strongly influences the probability of being gossiped. Finally, we discuss how the spread factor is able to be applied to other situations.

Lind, Pedro G.; da Silva, Luciano R.; Andrade, José S., Jr.; Herrmann, Hans J.

2007-09-01

376

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

National Technical Information Service (NTIS)

The risk assessment and mitigation tool advanced in this paper responds to the need for both a regional/global tool to evaluate the status of preparedness of individual countries and a more cooperative connection among regions. This preventive action tool...

D. F. Thompson R. P. Louie

2006-01-01

377

Eliciting the relative importance of risk factors concerning contagious animal diseases using conjoint analysis: a preliminary survey report  

Microsoft Academic Search

Conjoint analysis is a technique well known in marketing research to elicit consumer preferences and opinions. This paper describes the results of an experiment which explores the potential application of conjoint analysis in the field of veterinary epidemiology and economics. In this experiment, the method of conjoint analysis was used to elicit the opinion of experts about the relative importance

H. S. Horst; R. B. M. Huirne; A. A. Dijkhuizen

1996-01-01

378

Spread dynamics of invasive species  

PubMed Central

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.

Arim, Matias; Abades, Sebastian R.; Neill, Paula E.; Lima, Mauricio; Marquet, Pablo A.

2006-01-01

379

Comparative assessment of two commonly used commercial ELISA tests for the serological diagnosis of contagious agalactia of small ruminants caused by Mycoplasma agalactiae  

PubMed Central

Background Contagious agalactia (CA) of sheep and goats caused by Mycoplasma agalactiae is a widely occurring economically important disease that is difficult to control. The ELISA is commonly used for the serological detection of CA but it has some limitations and the performance of the available tests have not been properly evaluated. Two commercial ELISA kits are widely used, one involving a fusion protein as target antigen and the other a total antigen. The objectives were to compare these tests by evaluating: i. Their diagnostic sensitivity and specificity, the relevance of the recommended cut-off points, the correlation between the two tests, and, the correlation between serology data and the milk shedding of M. agalatiae; ii. The influence of extrinsic factors such as the targeted animal species, geographical origin of the samples, intra-specific variability of M. agalactiae and concurrent mycoplasma infections. A sample of 5900 animals from 211 farms with continuous CA monitoring for 20?years and no prior vaccination history was used. The infection status was known from prior bacteriological, epidemiological and serological monitoring with a complementary immunoblotting test. Results The average diagnostic sensitivity was 56% [51.8–59.8] for the fusion protein ELISA and 84% [81.3–87.2] for the total antigen ELISA, with noteworthy flock-related variations. The average diagnostic specificity for the fusion protein ELISA was 100% [99.9–100], and for the total antigen ELISA differed significantly between goats and sheep: 99.3% [97.4–99.9] and 95.7% [93.8–97.2] respectively. Experimental inoculations with different M. agalactiae strains revealed that the ELISA kits poorly detected the antibody response to certain strains. Furthermore, test performances varied according to the host species or geographical origin of the samples. Finally, the correlation between milk shedding of M. agalactiae and the presence of detectable antibodies in the blood was poor. Conclusions These serological tests are not interchangeable. The choice of a test will depend on the objectives (early detection of infection or disease control program), on the prevalence of infection and the control protocol used. Given the variety of factors that may influence performance, a preliminary assessment of the test in a given situation is recommended prior to widespread use.

2012-01-01

380

Gasping for truth : tracking the spread of SARS around the world  

NSDL National Science Digital Library

This is a lesson plan in which students investigate global responses to fighting the spread of severe acute respiratory syndrome. Students will read a newspaper article to discover what is being done to curb the spread of the deadly disease. Then, students will use a variety of different media to track the spread and other statistics related to the disease. Students will write news reports advising citizens of what to do in affected areas.

Dekorne, Clayton; Chin, Tanya Y.

2003-01-01

381

Delivery of Both Foot-and-Mouth Disease Virus Structural and Nonstructural Antigens Improves Protection of Swine  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foot-and-mouth disease virus (FMDV) is the etiological agent of one of the most contagious diseases affecting cloven-hoofed animals and is the most important constraint on trade in live animals and animal products. The current vaccine has limitations when used in disease-free countries including dif...

382

A novel protein-coding ORF72.2 gene was identified from Marek's disease virus strain CVI988  

Microsoft Academic Search

Marek's disease is a highly contagious disease of poultry characterized by rapid-on set of T-cell lymphomas, which is caused by Marek's disease virus (MDV), but its pathogenic mechanism is still not very clear. Recently, some new progress were achieved in molecular character of MDV. Along with the genomic sequencing of MDV serotype 1, some novel open reading frames (ORFs) were

Mingxing Tian; Yang Zhao; Min Shi; Yan Lin; Nianli Zou; Ping Liu; Xintian Wen; Sanjie Cao; Yong Huang

2010-01-01

383

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...

384

Evolved Disease-Avoidance Processes and Contemporary Anti-Social Behavior: Prejudicial Attitudes and Avoidance of People with Physical Disabilities  

Microsoft Academic Search

Drawing on evolutionary psychological logic, we describe a model that links evolved mechanisms of disease-avoidance to contemporary prejudices against individuals with physical disabilities. Because contagious diseases were often accompanied by anomalous physical features, humans plausibly evolved psychological mechanisms that respond heuristically to the perception of these features, triggering specific emotions (disgust, anxiety), cognitions (negative attitudes), and behaviors (avoidance). This disease-avoidance

Justin H. Park; Jason Faulkner; Mark Schaller

2003-01-01

385

Bordetella pertussis infection in infants: a reemerging disease.  

PubMed

Bordetella pertussis is a highly contagious bacterial disease currently on the rise in the United States. The most vulnerable age group is infants younger than 1 year old. The reasons for the current outbreak are multifactorial. The following is a case report describing a recent case of Bordetella pertussis infection admitted to a neonatal intensive care unit. PMID:23532029

Snapp, Barbara; Fischetti, Deborah

2013-04-01

386

How the devil facial tumor disease escapes host immune responses  

PubMed Central

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.

Siddle, Hannah V; Kaufman, Jim

2013-01-01

387

Worldwide spreading of economic crisis  

NASA Astrophysics Data System (ADS)

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.

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

2010-11-01

388

Epitope spreading occurs in active but not passive EAE induced by myelin basic protein  

Microsoft Academic Search

Using experimental allergic encephalomyelitis, EAE, as a model for the study of autoimmune demyelinating disease in the CNS, previous studies have indicated that spread may occur with respect to the specificity of T cell responses during disease. This phenomenon, known as epitope spreading, is central to therapeutic strategies in multiple sclerosis (MS). However, in EAE, the clinical course, neuropathology and

Rhonda R. Voskuhl; R. Wesley Farris; Kunihiko Nagasato; Henry F. McFarland; Monique Dubois Dalcq

1996-01-01

389

Antibody inhibition of human cytomegalovirus spread in epithelial cell cultures.  

PubMed

Anti-cytomegalovirus (CMV) antibodies reduce the incidence of CMV transmission and ameliorate the severity of CMV-associated disease. Neutralizing activity, measured as the ability of antibodies to prevent entry of cell-free virus, is an important component of natural immunity. However, in vivo CMV amplification may occur mainly via spread between adjacent cells within tissues. Thus, inhibition of cell-to-cell spread may be important when evaluating therapeutic antibodies or humoral responses to infection or immunization. In vitro CMV cell-to-cell spread is largely resistant to antibodies in fibroblast cultures but sensitive in endothelial cell cultures. In the present study antibodies in CMV hyperimmuneglobulin or seropositive human sera inhibited CMV cell-to-cell spread in epithelial cell cultures. Spread inhibition activity was quantitated with a GFP reporter assay employing GFP-tagged epithelialtropic variants of CMV strains Towne or AD169. Measurement of spread inhibition provides an additional parameter for the evaluation of candidate vaccines or immunotherapeutics and to further characterize the role of antibodies in controlling CMV transmission and disease. PMID:23669101

Cui, Xiaohong; Lee, Ronzo; Adler, Stuart P; McVoy, Michael A

2013-05-10

390

Description of an as Yet Unclassified DNA Virus from Diseased Cyprinus carpio Species  

Microsoft Academic Search

Numerous deaths of koi and common carp (Cyprinus carpio) were observed on many farms throughout Israel, resulting in severe financial losses. The lethal viral disease observed is highly contagious and extremely virulent, but morbidity and mortality are restricted to koi and common carp populations. Diseased fish exhibit fatigue and gasping movements in shallow water. Infected fish had interstitial nephritis and

Marina Hutoran; Ariel Ronen; Ayana Perelberg; Maya Ilouze; Arnon Dishon; Izhak Bejerano; Nissim Chen; Moshe Kotler

2005-01-01

391

Natural Killer Cells in Foot-and-Mouth Disease Virus Infection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. Immunological knowledge required to design a rational vaccine against FMDV is presently limited. We examined the reactivity of swine and cattle NK cells following infection for their capability to express intracell...

392

Molecular and Structural Bases for the Antigenicity of VP2 of Infectious Bursal Disease Virus  

Microsoft Academic Search

Infectious bursal disease virus (IBDV), a member of the family Birnaviridae, is responsible for a highly contagious and economically important disease causing immunosuppression in chickens. IBDV variants isolated in the United States exhibit antigenic drift affecting neutralizing epitopes in the capsid protein VP2. To understand antigenic determinants of the virus, we have used a reverse-genetics approach to introduce selected amino

Tobias Letzel; Fasseli Coulibaly; Felix A. Rey; Bernard Delmas; Erik Jagt; Adriaan A. M. W. van Loon; Egbert Mundt

2007-01-01

393

SNP discovery and marker development for disease resistance candidate genes in common carp (Cyprinus carpio)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Single nucleotide polymorphisms (SNPs) in immune response genes have been reported as markers of susceptibility to infectious diseases in human and livestock. A disease caused by cyprinid herpes virus 3 (CyHV-3) is highly contagious and virulent in common carp. With the aim to investigate the gene...

394

ConcepTest: Spreading Rate of Spreading Center  

NSDL National Science Digital Library

Scientists collect rock samples of the oceanic crust from a location that is 10 km from a spreading center. (1 km = 1000 m; 1 m = 100 cm; 1 cm = 10 mm.) The sampled rocks were found to be 200,000 years old. What ...

395

Detonation spreading in fine TATBs  

SciTech Connect

A test has been devised that permits rapid evaluation of the detonation-spreading (or corner-turning) properties of detonations in insensitive high explosives. The test utilizes a copper witness plate as the medium to capture performance data. Dent depth and shape in the copper are used as quantitative measures of the detonation output and spreading behavior. The merits of the test are that it is easy to perform with no dynamic instrumentation, and the test requires only a few grams of experimental explosive materials.

Kennedy, J.E.; Lee, K.Y.; Spontarelli, T.; Stine, J.R.

1998-12-31

396

Worldwide Spread of Dengue Virus Type 1  

PubMed Central

Background DENV-1 is one of the four viral serotypes that causes Dengue, the most common mosquito-borne viral disease of humans. The prevalence of these viruses has grown in recent decades and is now present in more than 100 countries. Limited studies document the spread of DENV-1 over the world despite its importance for human health. Methodology/Principal Findings We used representative DENV-1 envelope gene sequences to unravel the dynamics of viral diffusion under a Bayesian phylogeographic approach. Data included strains from 45 distinct geographic locations isolated from 1944 to 2009. The estimated mean rate of nucleotide substitution was 6.56×10?4 substitutions/site/year. The larger genotypes (I, IV and V) had a distinctive phylogenetic structure and since 1990 they experienced effective population size oscillations. Thailand and Indonesia represented the main sources of strains for neighboring countries. Besides, Asia broadcast lineages into the Americas and the Pacific region that diverged in isolation. Also, a transmission network analysis revealed the pivotal role of Indochina in the global diffusion of DENV-1 and of the Caribbean in the diffusion over the Americas. Conclusions/Significance The study summarizes the spatiotemporal DENV-1 worldwide spread that may help disease control.

Villabona-Arenas, Christian Julian; Zanotto, Paolo Marinho de Andrade

2013-01-01

397

Rapid Detection of Contagious Bovine Pleuropneumonia by a Mycoplasma mycoides subsp. mycoides SC Capsular Polysaccharide-Specific Antigen Detection Latex Agglutination Test  

Microsoft Academic Search

A latex agglutination test (LAT) has been developed for the diagnosis of contagious bovine pleuropneumonia (CBPP). The latex microspheres were coated with MmmSC polyclonal immunoglobulin G antiserum and detected MmmSC antigen in the serum of cattle infected with CBPP and in growth medium containing MmmSC. The specific antigen recognizsed by this test appeared to be the capsular polysaccharide (CPS). The

John B. March; Karen Kerr; Benedict Lema

2003-01-01

398

Bridging a yawning chasm: EEG investigations into the debate concerning the role of the human mirror neuron system in contagious yawning.  

PubMed

Ongoing debate in the literature concerns whether there is a link between contagious yawning and the human mirror neuron system (hMNS). One way of examining this issue is with the use of the electroencephalogram (EEG) to measure changes in mu activation during the observation of yawns. Mu oscillations are seen in the alpha bandwidth of the EEG (8-12 Hz) over sensorimotor areas. Previous work has shown that mu suppression is a useful index of hMNS activation and is sensitive to individual differences in empathy. In two experiments, we presented participants with videos of either people yawning or control stimuli. We found greater mu suppression for yawns than for controls over right motor and premotor areas, particularly for those scoring higher on traits of empathy. In a third experiment, auditory recordings of yawns were compared against electronically scrambled versions of the same yawns. We observed greater mu suppression for yawns than for the controls over right lateral premotor areas. Again, these findings were driven by those scoring highly on empathy. The results from these experiments support the notion that the hMNS is involved in contagious yawning, emphasise the link between contagious yawning and empathy, and stress the importance of good control stimuli. PMID:22198677

Cooper, Nicholas R; Puzzo, Ignazio; Pawley, Adam D; Bowes-Mulligan, Ruby A; Kirkpatrick, Emma V; Antoniou, Pavlina A; Kennett, Steffan

2012-06-01

399

The role of hybridization in the origin and spread of asexuality in Daphnia.  

PubMed

The molecular mechanisms leading to asexuality remain little understood despite their substantial bearing on why sexual reproduction is dominant in nature. Here, we examine the role of hybridization in the origin and spread of obligate asexuality in Daphnia pulex, arguably the best-documented case of contagious asexuality. Obligately parthenogenetic (OP) clones of D. pulex have traditionally been separated into 'hybrid' (Ldh SF) and 'nonhybrid' (Ldh SS) forms because the lactase dehydrogenase (Ldh) locus distinguishes the cyclically parthenogenetic (CP) lake dwelling Daphnia pulicaria (Ldh FF) from its ephemeral pond dwelling sister species D. pulex (Ldh SS). The results of our population genetic analyses based on microsatellite loci suggest that both Ldh SS and SF OP individuals can originate from the crossing of CP female F1 (D. pulex × D. pulicaria) and backcross with males from OP lineages carrying genes that suppress meiosis specifically in female offspring. In previous studies, a suite of diagnostic markers was found to be associated with OP in Ldh SS D. pulex lineages. Our association mapping supports a similar genetic mechanism for the spread of obligate parthenogenesis in Ldh SF OP individuals. Interestingly, our study shows that CP D. pulicaria carry many of the diagnostic microsatellite alleles associated with obligate parthenogenesis. We argue that the assemblage of mutations that suppress meiosis and underlie obligate parthenogenesis in D. pulex originated due to a unique historical hybridization and introgression event between D. pulex and D. pulicaria. PMID:23879327

Xu, Sen; Innes, David J; Lynch, Michael; Cristescu, Melania E

2013-07-23

400

3D Fire Spread Animations  

NSDL National Science Digital Library

These excellent animations overlay animations of fire spread on 3D terrain that incorporates satellite imagery. A timeline shows the animation's current time relative to the fire occurrence, and an inset map provides an overhead view of the fire on a map that shows fuels by location. Animations are available for several wildfires that occurred in California.

Johson, Harry D.; University, San D.

401

Mid-Ocean Ridge Spreading  

NSDL National Science Digital Library

In this earth science activity (page 14 of the PDF), learners use layers of closed-cell foam to create their own model of the mid-ocean ridge in order to simulate seafloor spreading. Although this was created as a post-visit activity for a workshop about earth processes, it also makes an excellent stand alone activity.

Cosi

2009-01-01

402

Device for Spreading Tire Casings.  

National Technical Information Service (NTIS)

A microfiche of the abstract contains graphic information. A tire bead spreader has fixed stops on either side of the splay levers so as to work with lever rollers and spread the levers into top and bottom positions. The return spring is coupled at the en...

B. I. Ivanov G. G. Torgovtsev V. M. Voznesenskii

1972-01-01

403

Use of personal digital assistant devices in order to access, consult and apply a corpus of clinical guidelines and decision-based support documentation like the Italian SPREAD Guidelines on stroke disease  

Microsoft Academic Search

During the past few years, personal digital assistants (PDAs) have become widespread commodities, like computers and mobile\\u000a phones. Many health-care providers, particularly physicians, routinely use PDAs in their everyday work. Accessing guidelines\\u000a and clinical decision-based support tools, such as the downloadable version of the Italian SPREAD Guidelines represents one\\u000a of the most important and common clinical applications. The current experience

I. Cricelli

2006-01-01

404

New Insights into the Role of MHC Diversity in Devil Facial Tumour Disease  

PubMed Central

Background Devil facial tumour disease (DFTD) is a fatal contagious cancer that has decimated Tasmanian devil populations. The tumour has spread without invoking immune responses, possibly due to low levels of Major Histocompatibility Complex (MHC) diversity in Tasmanian devils. Animals from a region in north-western Tasmania have lower infection rates than those in the east of the state. This area is a genetic transition zone between sub-populations, with individuals from north-western Tasmania displaying greater diversity than eastern devils at MHC genes, primarily through MHC class I gene copy number variation. Here we test the hypothesis that animals that remain healthy and tumour free show predictable differences at MHC loci compared to animals that develop the disease. Methodology/Principal Findings We compared MHC class I sequences in 29 healthy and 22 diseased Tasmanian devils from West Pencil Pine, a population in north-western Tasmania exhibiting reduced disease impacts of DFTD. Amplified alleles were assigned to four loci, Saha-UA, Saha-UB, Saha-UC and Saha-UD based on recently obtained genomic sequence data. Copy number variation (caused by a deletion) at Saha-UA was confirmed using a PCR assay. No association between the frequency of this deletion and disease status was identified. All individuals had alleles at Saha-UD, disproving theories of disease susceptibility relating to copy number variation at this locus. Genetic variation between the two sub-groups (healthy and diseased) was also compared using eight MHC-linked microsatellite markers. No significant differences were identified in allele frequency, however differences were noted in the genotype frequencies of two microsatellites located near non-antigen presenting genes within the MHC. Conclusions/Significance We did not find predictable differences in MHC class I copy number variation to account for differences in susceptibility to DFTD. Genotypic data was equivocal but indentified genomic areas for further study.

Wright, Belinda; Hamede, Rodrigo; Levan, Laura; Jones, Menna; Ujvari, Beata; Belov, Katherine

2012-01-01

405

Molecular characterization of partial fusion gene and C-terminus extension length of haemagglutinin-neuraminidase gene of recently isolated Newcastle disease virus isolates in Malaysia  

Microsoft Academic Search

BACKGROUND: Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a highly contagious disease of birds and has been one of the major causes of economic losses in the poultry industry. Despite routine vaccination programs, sporadic cases have occasionally occurred in the country and remain a constant threat to commercial poultry. Hence, the present study was aimed to characterize

Ayalew Berhanu; Aini Ideris; Abdul R Omar; Mohd Hair Bejo

2010-01-01

406

Modelling the spread of Wolbachia in spatially heterogeneous environments  

PubMed Central

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.

Hancock, Penelope A.; Godfray, H. Charles J.

2012-01-01

407

Directional spread of alphaherpesviruses in the nervous system.  

PubMed

Alphaherpesviruses are pathogens that invade the nervous systems of their mammalian hosts. Directional spread of infection in the nervous system is a key component of the viral lifecycle and is critical for the onset of alphaherpesvirus-related diseases. Many alphaherpesvirus infections originate at peripheral sites, such as epithelial tissues, and then enter neurons of the peripheral nervous system (PNS), where lifelong latency is established. Following reactivation from latency and assembly of new viral particles, the infection typically spreads back out towards the periphery. These spread events result in the characteristic lesions (cold sores) commonly associated with herpes simplex virus (HSV) and herpes zoster (shingles) associated with varicella zoster virus (VZV). Occasionally, the infection spreads transsynaptically from the PNS into higher order neurons of the central nervous system (CNS). Spread of infection into the CNS, while rarer in natural hosts, often results in severe consequences, including death. In this review, we discuss the viral and cellular mechanisms that govern directional spread of infection in the nervous system. We focus on the molecular events that mediate long distance directional transport of viral particles in neurons during entry and egress. PMID:23435239

Kramer, Tal; Enquist, Lynn W

2013-02-11

408

Directional Spread of Alphaherpesviruses in the Nervous System  

PubMed Central

Alphaherpesviruses are pathogens that invade the nervous systems of their mammalian hosts. Directional spread of infection in the nervous system is a key component of the viral lifecycle and is critical for the onset of alphaherpesvirus-related diseases. Many alphaherpesvirus infections originate at peripheral sites, such as epithelial tissues, and then enter neurons of the peripheral nervous system (PNS), where lifelong latency is established. Following reactivation from latency and assembly of new viral particles, the infection typically spreads back out towards the periphery. These spread events result in the characteristic lesions (cold sores) commonly associated with herpes simplex virus (HSV) and herpes zoster (shingles) associated with varicella zoster virus (VZV). Occasionally, the infection spreads transsynaptically from the PNS into higher order neurons of the central nervous system (CNS). Spread of infection into the CNS, while rarer in natural hosts, often results in severe consequences, including death. In this review, we discuss the viral and cellular mechanisms that govern directional spread of infection in the nervous system. We focus on the molecular events that mediate long distance directional transport of viral particles in neurons during entry and egress.

Kramer, Tal; Enquist, Lynn W.

2013-01-01

409

Smallpox: emergence, global spread, and eradication.  

PubMed

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. PMID:7529932

Fenner, F

1993-01-01

410

History lessons.  

PubMed

There was a time when epidemics were solely the province of infectious diseases. Indeed, most dictionary definitions of the term refer first to contagious diseases that spread rapidly among a given population. PMID:24133699

Metcalfe, Sarah

2013-08-01

411

Epidemic spreading by objective traveling  

NASA Astrophysics Data System (ADS)

A fundamental feature of agent traveling in social networks is that traveling is usually not a random walk but with a specific destination and goes through the shortest path from starting to destination. A serious consequence of the objective traveling is that it may result in a fast epidemic spreading, such as SARS etc. In this letter we present a reaction-traveling model to study how the objective traveling influences the epidemic spreading. We consider a random scale-free meta-population network with sub-population at each node. Through a SIS model we theoretically prove that near the threshold of epidemic outbreak, the objective traveling can significantly enhance the final infected population and the infected fraction at a node is proportional to its betweenness for the traveling agents and approximately proportional to its degree for the non-traveling agents. Numerical simulations have confirmed the theoretical predictions.

Tang, Ming; Liu, Zonghua; Li, Baowen

2009-07-01

412

Chicken Heat Shock Protein 90 Is a Component of the Putative Cellular Receptor Complex of Infectious Bursal Disease Virus  

Microsoft Academic Search

Infectious bursal disease virus (IBDV) causes a highly contagious disease in young chicks and leads to significant economic losses in the poultry industry. The capsid protein VP2 of IBDV plays an important role in virus binding and cell recognition. VP2 forms a subviral particle (SVP) with immunogenicity similar to that of the IBDV capsid. In the present study, we first

Ta-Wei Lin; Chi-Wen Lo; Su-Yuan Lai; Ruey-Jane Fan; Chao-Jung Lo; Yu-mei Chou; Rekha Thiruvengadam; Andrew H.-J. Wang; Min-Ying Wang

2007-01-01

413

Economic Impacts of Potential Food and Mouth Disease Agroterrorism in the United States: A Computable General Equilibrium Analysis  

Microsoft Academic Search

Foot and mouth disease (FMD) is highly contagious and has high agro-terrorism potential because it can be easily turned into a weapon. An outbreak of FMD in developed countries results in massive slaughtering (for disease control) and disruptions in meat supply chains and trade, with potentially large economic losses. Although the United States has been FMD-free since 1929, the potential

Gbadebo Oladosu; Adam Z. Rose; Bumsoo Lee

2009-01-01

414

POTENTIAL ROLE OF FLIES IN THE PERSISTENCE AND DISPERSAL OF EXOTIC NEWCASTLE DISEASE VIRUS IN SOUTHERN CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Exotic Newcastle Disease (END) is a highly virulent and contagious disease affecting poultry and other birds with the potential of causing 100% mortality in unvaccinated poultry. Transmission of END virus to susceptible birds is primarily thought to occur via direct contact with infected birds or in...

415

Recombinant VP60 in the form of virion-like particles as a potential vaccine against rabbit hemorrhagic disease virus  

Microsoft Academic Search

Rabbit hemorrhagic disease virus (RHDV) which causes a highly contagious disease of wild and domestic rabbits belongs to the family Caliciviridae. It is a small, positive single-stranded RNA virus with a genome of 7.5 kb and has a diameter of approximately 40 nm. In negatively stained electron micrographs the virus shows typical calicivirus morphology with regularly arranged cup- shaped structures

Beata Gromadzka; Andrzej Fitzner; Andrzej K?sy

2006-01-01

416

Inefficient epidemic spreading in scale-free networks.  

PubMed

Highly heterogeneous degree distributions yield efficient spreading of simple epidemics through networks, but can be inefficient with more complex epidemiological processes. We study diseases with nonlinear force of infection whose prevalences can abruptly collapse to zero while decreasing the transmission parameters. We find that scale-free networks can be unable to support diseases that, on the contrary, are able to persist at high endemic levels in homogeneous networks with the same average degree. PMID:18352096

Piccardi, Carlo; Casagrandi, Renato

2008-02-26

417

High Interest Rates, Spreads, and the Costs of Intermediation.  

National Technical Information Service (NTIS)

Contents: High real interest rates and spreads: An introduction (Spreads and explicit taxes, spreads and implicit taxes on financial intermediation, spreads, operating costs and profits, conclusions and an Agenda for reducing spreads). The costs of interm...

J. A. Hanson R. R. Rocha

1986-01-01

418

Disease control during the colonial period in Australia.  

PubMed

The first permanent European settlers of Australia arrived in 1788 to establish a penal colony at Sydney, New South Wales (NSW). As the colony grew and wool production increased, more free settlers and emancipists developed farming in inland Australia. During the 1840s veterinarians commenced arriving in small numbers but they were not closely associated with the development and execution of disease control programs, which was left to lay inspectors of stock. The arrival of William Tyson Kendall and coordinated action with Graham Mitchell led to the establishment of a private veterinary college following the passage of veterinary surgeons legislation in Victoria. From this time, veterinarians came to be appointed to positions formerly occupied by lay inspectors and the veterinary profession was able to take up the role of planning and executing government-led disease control programs. From a colony relying on wool for export to the UK, technical advancements in meat freezing and pasture improvement widened the range and increased the quantity of exported products. Before the advent of veterinary advances, sheep scab was eradicated, a vaccine was developed for anthrax and glanders infection of horses was prevented entry to Australia. Graduates from the Melbourne Veterinary College spread across Australia and in this period a conservative quarantine policy was developed following inaction to control an outbreak of contagious bovine pleuropneumonia (CBPP) and the escape of rabbits to form a plague across the continent. Coordinated control of CBPP had to await the next century and advancement of technology increased our understanding of bacteriology and immunity of infectious diseases. Veterinary services were provided to the militia sent by the colonies to the Boer Wars in South Africa 1987-1901 and the veterinarians from Victoria were led by an Australian trained veterinarian. PMID:21696369

Turner, A J

2011-07-01

419

The impact of awareness on epidemic spreading in networks  

NASA Astrophysics Data System (ADS)

We explore the impact of awareness on epidemic spreading through a population represented by a scale-free network. Using a network mean-field approach, a mathematical model for epidemic spreading with awareness reactions is proposed and analyzed. We focus on the role of three forms of awareness including local, global, and contact awareness. By theoretical analysis and simulation, we show that the global awareness cannot decrease the likelihood of an epidemic outbreak while both the local awareness and the contact awareness can. Also, the influence degree of the local awareness on disease dynamics is closely related with the contact awareness.

Wu, Qingchu; Fu, Xinchu; Small, Michael; Xu, Xin-Jian

2012-03-01

420

Lexical Ambiguity: Making a Case against Spread  

ERIC Educational Resources Information Center

|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."|

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

2012-01-01

421

Melanoma: How It Returns, Where It Spreads  

MedlinePLUS

SkinCancerNet Article Melanoma: How It Returns, Where It Spreads Melanoma is known as "the most lethal form ... 39% Table 1: Where Melanoma Most Likely to Spread Source: Meyers ML, Balch CM. “Diagnosis and Treatment ...

422

An Introduction to Spread Spectrum Modulation.  

National Technical Information Service (NTIS)

This technical note provides a survey of spread spectrum techniques and applications. Included are discussions of the various spread spectrum modulating techniques, system processing gains, and resistivity to jamming and interference. (Author)

R. E. Lueg R. A. Freet

1975-01-01

423

Hydroclimatological And Anthropogenic Drivers For Cholera Spreading  

NASA Astrophysics Data System (ADS)

The nature of waterborne diseases, among which cholera has a prominent importance, calls for a better understanding of the link between epidemic spreading, water and climate. To this end, we have developed a framework which involves a network-based description of a river system, connected with local communities which act as nodes of the network. This has allowed us to produce consistent simulations of real case studies. More recent investigations comprise the evaluation of the spreading velocity of an epidemic wave by means of a reaction-diffusion modeling approach. In particular, we have found that both transport processes and epidemiological quantities, such as the basic reproduction number, have a crucial effect in controlling the spreading of the epidemics. We first developed a description of bacterial movement along the network driven by advection and diffusion; afterward, we have included the movement of human populations. This latter model allowed us to establish the conditions that can trigger epidemic waves that start from the coastal region, where bacteria are autochthonous, and travel inland. In particular, our findings suggest that even relatively low values of human diffusion can have the epidemic propagate upstream. The interaction between climate, hydrology and epidemic events is still much debated, since no clear correlation between climatologic and epidemiological phenomena has emerged so far. However, a spatial assessment of hydrological and epidemiological mechanisms could be crucial to understand the evolution of cholera outbreaks. In particular, a hotly debated topic is the understanding of the mechanisms that can generate patterns of cholera incidence that exhibit an intra-annual double peak, as frequently observed in endemic region such as Bangladesh. One of the possible explanations proposed in the literature is that spring droughts cause bacteria concentration in water to rise dramatically, triggering the first peak. On the other hand similar mechanisms can occur during flood recessions in autumn together with major water sanitation system failures and higher population density. We show here the results of an ecohydrological model that couples the dynamics of the disease to a description of both the local water reservoir and of the local river section. The goal of this modeling exercise is to reproduce and understand the mechanisms behind intra-annual cholera incidence dynamics driven by hydrologic variability.

Righetto, Lorenzo; Bertuzzo, Enrico; Mari, Lorenzo; Casagrandi, Renato; Gatto, Marino; Rinaldo, Andrea

2010-05-01

424

Lymphatic spread of osteosarcoma shown by Tc-99m-MDP scintigraphy  

SciTech Connect

Osteosarcoma usually spreads via the blood stream, resulting in pulmonary and skeletal metastases. The value of bone imaging in the management of these patients is widely accepted. Less commonly, the disease spreads via the lymphatics. Such a case is reported to show that bone imaging will detect progressive involvement of the lymph nodes.

Heyman, S.

1980-12-01

425

Spread of an introduced vector-borne banana virus in Hawaii  

Microsoft Academic Search

Emerging diseases are increasing in incidence; therefore, understanding how pathogens are introduced into new regions and cause epidemics is of importance for the development of strategies that may hinder their spread. We used molecular data to study how a vector- borne banana virus, Banana bunchy top virus (BBTV), spread in Hawaii after it was first detected in 1989. Our analyses

RODRIGO P. P. ALMEIDA; GORDON M. BENNETT; MANDY D. ANHALT; CHI-WEI TSAI; PATRICK O’GRADY

2009-01-01

426

The importance of location in contact networks: Describing early epidemic spread using spatial social network analysis  

Microsoft Academic Search

This paper explores methods for describing the dynamics of early epidemic spread and the clustering of infected cases in space and time when an underlying contact network structure is influencing disease spread. A novel method of describing an epidemic is presented that applies social network analysis to characterise the importance of both spatial location and contact network position. This method

Simon M. Firestone; Michael P. Ward; Robert M. Christley; Navneet K. Dhand

427

Cortical spreading depression: An enigma  

NASA Astrophysics Data System (ADS)

The brain is a complex organ with active components composed largely of neurons, glial cells, and blood vessels. There exists an enormous experimental and theoretical literature on the mechanisms involved in the functioning of the brain, but we still do not have a good understanding of how it works on a gross mechanistic level. In general, the brain maintains a homeostatic state with relatively small ion concentration changes, the major ions being sodium, potassium, and chloride. Calcium ions are present in smaller quantities but still play an important role in many phenomena. Cortical spreading depression (CSD for short) was discovered over 60 years ago by A.A.P. Leão, a Brazilian physiologist doing his doctoral research on epilepsy at Harvard University, “Spreading depression of activity in the cerebral cortex," J. Neurophysiol., 7 (1944), pp. 359-390. Cortical spreading depression is characterized by massive changes in ionic concentrations and slow nonlinear chemical waves, with speeds on the order of mm/min, in the cortex of different brain structures in various experimental animals. In humans, CSD is associated with migraine with aura, where a light scintillation in the visual field propagates, then disappears, and is followed by a sustained headache. To date, CSD remains an enigma, and further detailed experimental and theoretical investigations are needed to develop a comprehensive picture of the diverse mechanisms involved in producing CSD. A number of mechanisms have been hypothesized to be important for CSD wave propagation. In this paper, we briefly describe several characteristics of CSD wave propagation, and examine some of the mechanisms that are believed to be important, including ion diffusion, membrane ionic currents, osmotic effects, spatial buffering, neurotransmitter substances, gap junctions, metabolic pumps, and synaptic connections. Continuum models of CSD, consisting of coupled nonlinear diffusion equations for the ion concentrations, and a discrete lattice-Boltzmann method approach will be described. Also, we will describe some open problems and remaining challenges.

Miura, R. M.; Huang, H.; Wylie, J. J.

2007-08-01

428

Eliminating Long-Distance Consonantal Spreading  

Microsoft Academic Search

Past theoretical analyses have claimed that some languages employ a special type of phonological spreading of a consonant over a vowel, long-distance consonantal spreading. I argue that this type of spreading can and must be eliminated from the theory, by reducing it to segmental copying as in reduplication. This elimination is first motivated from a number of perspectives, including considerations

Diamandis Gafos

1998-01-01

429

The Spread Wide Area Group Communication System  

Microsoft Academic Search

Building a wide area group communication system is a challenge. This paper presents the design and pro tocols of the Spread wide area group communication system. Spread integrates two low-level protocols: one for lo cal area networks called Ring, and one for the wide area net work connecting them, called Hop. Spread decouples the dissemination and local reliability mechanisms from

Yair Amir; Jonathan Stanton

1998-01-01

430

Modeling the Spread of Active Worms  

Microsoft Academic Search

Active worms spread in an automated fashion and can flood the Internet in a very short time. Modeling the spread of active worms can help us understand how active worms spread, and how we can monitor and defend against the propagation of worms effectively. In this paper, we present a mathematical model, referred to as the Analytical Active Worm Propagation

Zesheng Chen; Lixin Gao; Kevin A. Kwiat

2003-01-01

431

Epidemic spread in coupled populations with seasonally varying migration rates  

NASA Astrophysics Data System (ADS)

The H5N1 strain of avian influenza has spread worldwide, and this spread may be due to seasonal migration of birds and mixing of birds from different regions in the wintering grounds. We studied a multipatch model for avian influenza with seasonally varying migration rates. The bird population was divided into two spatially distinct patches, or subpopulations. Within each patch, the disease followed the SIR (susceptible-infected-recovered) model for epidemic spread. Migration rates were varied periodically, with a net flux toward the breeding grounds during the spring and towards the wintering grounds during the fall. The case of two symmetric patches reduced to single-patch SIR dynamics. However, asymmetry in the birth and contact rates in the breeding grounds and wintering grounds led to bifurcations to longer period orbits and chaotic dynamics. We studied the bifurcation structure of the model and the phase relationships between outbreaks in the two patches.

Muzyczyn, Adam; Shaw, Leah B.

2009-03-01

432

Epidemic spreading on interconnected networks  

NASA Astrophysics Data System (ADS)

Many real networks are not isolated from each other but form networks of networks, often interrelated in nontrivial ways. Here, we analyze an epidemic spreading process taking place on top of two interconnected complex networks. We develop a heterogeneous mean-field approach that allows us to calculate the conditions for the emergence of an endemic state. Interestingly, a global endemic state may arise in the coupled system even though the epidemics is not able to propagate on each network separately and even when the number of coupling connections is small. Our analytic results are successfully confronted against large-scale numerical simulations.

Saumell-Mendiola, Anna; Serrano, M. Ángeles; Boguñá, Marián

2012-08-01

433

Hybrid spread spectrum radio system  

DOEpatents

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.

Smith, Stephen F. (London, TN); Dress, William B. (Camas, WA)

2010-02-02

434

Epidemic spreading on interconnected networks.  

PubMed

Many real networks are not isolated from each other but form networks of networks, often interrelated in nontrivial ways. Here, we analyze an epidemic spreading process taking place on top of two interconnected complex networks. We develop a heterogeneous mean-field approach that allows us to calculate the conditions for the emergence of an endemic state. Interestingly, a global endemic state may arise in the coupled system even though the epidemics is not able to propagate on each network separately and even when the number of coupling connections is small. Our analytic results are successfully confronted against large-scale numerical simulations. PMID:23005824

Saumell-Mendiola, Anna; Serrano, M Ángeles; Boguñá, Marián

2012-08-10

435

Spread spectrum random access networks  

NASA Astrophysics Data System (ADS)

A new method of code allocation in Code Division Multiple Access is proposed, based on partitioned information 'classes' (CDMA-IC), that is particularly efficient in meeting multicasting needs. Transmitters choose spreading codes based on the types of messages they are transmitting, and receivers listen to codes corresponding to the types of messages they are interested in. The performance of this approach can exceed that of both the traditional receiver-directed codes or broadcast codes in environments where there are several multicast groups (in which a given message is of interest to more than one node), or where it is difficult to know what types of messages (out of a fixed set of message types) a receiver is interested in at any particular time. Performance is further enhanced when receivers can simultaneously attempt to correlate multiple spreading codes. A broad theoretical framework was developed for the CDMA-IC concept and numerical results through simulation were obtained and compared to receiver-directed and broadcasting scenarios.

Sastry, Ambatipudi R.

1993-10-01

436

Use of the polymerase chain reaction for the diagnosis of natural infection of chickens and turkeys with Marek's disease virus and reticuloendotheliosis virus  

Microsoft Academic Search

Marek's disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by a herpesvirus, while reticuloendotheliosis (REV) virus is an avian C?type retrpvirus that causes bursal and nonbursal lymphomas which often closely resemble MDV lymphomas. To provide a rapid and sensitive means of diagnosing and differentiating between these two neoplastic conditions, we have applied the PCR. The primers chosen

Irit Davidson; Anya Borovskaya; S. Perl; M. Malkinson

1995-01-01

437

RAPID PROTECTION OF CATTLE FROM DIRECT CHALLENGE WITH FOOT-AND-MOUTH DISEASE VIRUS (FMDV) BY INOCULATION WITH AN ADENOVIRUS VECTORED FMDV SUBUNIT VACCINE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen of cloven-hoofed animals including cattle and swine. Recent outbreaks in a number of previously disease-free countries have had significant adverse economic effects. The use of the current FMD vaccine, an inactivated whole virus p...

438

VACCINATION AGAINST FOOT-AND-MOUTH DISEASE VIRUS CONFERS COMPLETE CLINICAL PROTECTION IN 7 DAYS AND PARTIAL PROTECTION IN 4 DAYS:USE IN EMERGENCY OUTBREAK RESPONSE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Recent outbreaks of foot-and-mouth disease virus (FMDV) demonstrate this highly contagious viral infection of cloven hoofed animals continues to be a significant economic problem worldwide. Debate about the most effective way to respond to FMD outbreaks in disease-free countries continues to center ...

439

The 2.6Angstrom Structure of Infectious Bursal Disease Virus-Derived T=1 Particles Reveals New Stabilizing Elements of the Virus Capsid  

Microsoft Academic Search

Infectious bursal disease virus (IBDV), a member of the Birnaviridae family, is a double-stranded RNA virus that causes a highly contagious disease in young chickens leading to significant economic losses in the poultry industry. The VP2 protein, the only structural component of the IBDV icosahedral capsid, spontaneously assembles into T1 subviral particles (SVP) when individually expressed as a chimeric gene.

D. Garriga; J. Querol-Audi; F. Abaitua; I. Saugar; J. Pous; N. Verdaguer; J. R. Caston; J. F. Rodriguez

2006-01-01

440

Cytokine mRNA expression in foot-and-mouth disease virus (FMDV) persistently infected bovine pharynx cultures: effect of IFNgamma on replication of persistent virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foot-and-mouth disease virus (FMDV), a member of the family Picornaviridae, genus Aphtovirus, causes a highly contagious disease in livestock. Following acute infection in ruminants, up to 50% of both vaccinated and non-vaccinated animals become persistently infected asymptomatic carriers with low-l...

441

RECOMBINANT ENGINEERED SAT1 FOOT-AND-MOUTH DISEASE VIRUS AS AN APPROACH TO INVESTIGATE RECEPTOR USAGE AND GROWTH DETERMINANTS OF OUTBREAK STRAINS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foot-and-mouth desease (FMD), a highly contagious viral disease of cattle, sheep, pigs and other cloven-hoofed animals has recently caused devastating epidemics world-wide. In the three South African Territories (SAT) types of foot-and-mouth disease virus (FMDV), the aetiological agent display grea...

442

RAPID PROTECTION OF CATTLE FROM DIRECT CHALLENGE WITH FOOT-AND-MOUTH DISEASE VIRUS (FMDV) BY INOCULATION WITH AN ADENOVIRUS VECTORED FMDV SUBUNIT VACCINE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen of cloven-hoofed animals including cattle and swine. Recent outbreaks in a number of previously disease-free countries have had significant adverse economic effects. The use of the current FMD vaccine, an inactivated whole virus pre...

443

Possible spread of African horse sickness on the wind  

PubMed Central

Analyses of outbreaks of African horse sickness showed that movement of infected Culicoides midges on the wind was most likely responsible for the spread of the disease over the sea from Morocco to Spain in 1966, from Turkey to Cyprus in 1960, and from Senegal to the Cape Verde Islands in 1943. The pattern of spread of the epidemic in the Middle East in 1960 could have been laid down by the infected midges carried on spells of south-east winds, and analyses of outbreaks in Algeria in 1965 and India in 1960 also suggested windborne spread of the disease. Each spread occurred when the presence of virus, host and vector coincided either with a spell of winds unusual for a particular time of year (Spain, Cyprus, Cape Verde Islands and Algeria) or with a series of disturbances usual at that time of the year (Middle East and India). Inferred flight endurance of the midge varied up to at least 20 h and flight range from 40 to 700 km. Flight occurred when temperatures were likely to have been in the range of 15-25 °C if it was at night or 20 to about 40 °C if it was by day. It is suggested that likely movements of midges on the wind can be estimated from synoptic weather charts, and should be taken into account when planning control of the disease in the face of an outbreak. Such control includes a ban on movement of horses, vaccination and spraying of insecticide. The risk of spread to countries outside the endemic areas should be assessed by reference to possible wind dispersal of infected midges.

Sellers, R. F.; Pedgley, D. E.; Tucker, M. R.

1977-01-01

444

Spreading code protocols for distributed spread-spectrum packet radio networks  

Microsoft Academic Search

Spreading code protocols for a distributed spread-spectrum packet radio network are presented. A distributed single-hop system (i.e. each terminal can hear all other terminals) with the users approximately synchronized and a set of prespecified spreading codes are presented. The spreading cod