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1

Isolation precautions to prevent the spread of contagious diseases.  

PubMed

This article explores the use of isolation precautions to prevent the spread of infection. The standard infection control precautions, which should be undertaken routinely with all patients, and the additional measures which should be adopted when a patient has a specific infection, are discussed. The use of single room accommodation for patients with infections is debated. PMID:19263962

Gould, D

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

Invited review: The role of contagious disease in udder health  

Microsoft Academic Search

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,

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

2009-01-01

4

Contagious Disease Dynamics for Biological Warfare and Bioterrorism Casualty Assessments.  

National Technical Information Service (NTIS)

This investigation focuses on the spread of a contagious disease subsequent to the military employment of a biological weapon or an act of bioterrorism. Of particular interest are expected or average time histories of four cohorts: (I) Susceptible individ...

J. N. Bombardt

2000-01-01

5

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. PMID:19762787

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

2009-01-01

6

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

E-print Network

Flu is a serious contagious disease. Each year in the United States, on average, more than 200,000 people are hospitalized and 36,000 people die from seasonal flu complications. This flu season could be worse. There is a new and very different flu virus spreading worldwide among people called novel or new

Ferrara, Katherine W.

7

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

8

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.

9

Risk and economic consequences of contagious animal disease introduction  

Microsoft Academic Search

Introduction<\\/strong>Within the European Union, epidemics of contagious animal diseases such as Classical Swine Fever (CSF) and Foot-and-Mouth Disease (FMD) are to be eradicated according to strict EU- prescriptions including stamping-out of infected herds, establishment of control and surveillance zones with complete standstill of animals and possible export bans on live animals. Epidemics clearly have a serious impact, in particular on

H. S. Horst

1998-01-01

10

[Highly contagious diseases with human-to-human transmission].  

PubMed

Highly contagious diseases are caused by various biological agents that pose a risk to individuals and may have a potential for public health impact. They result in high mortality and morbidity rates, might cause public panic and therefore require special measures. The pathogens that can be easily disseminated or transmitted from person to person are the riskiest for clinicians (Ebola virus, Marburg virus, Lassa virus, Crimean-Congo hemorrhagic fever virus, Variola major, SARS virus and Yersinia pestis). Human-to-human transmission has not been confirmed for the other biological agents and therefore they pose a very low risk for population. PMID:23386507

Rybka, Aleš; Szanyi, Juraj; Kapla, Jaroslav; Plíšek, Stanislav

2012-12-01

11

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

12

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

13

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

2012-06-01

14

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

15

Epidemiology: Understanding Disease Spread  

NSDL National Science Digital Library

Factors that influence disease spread throughout populations can be explored with the program Epidemiology. Both population and disease characteristics can be modeled over different time periods. The Susceptible- Infected- Recovered (SIR) model enables us to make predictions based on significant variables such as the flow of new susceptibles in to the population, transmission rates, disease deaths, and the duration of the disease. Ebola is used as a model organism and epidemiology is presented from both a microbiological and social perspective. * build epidemiological models of different diseases, design strategies for disease control, and test the effectiveness of these strategies on virtual populations

Marion Fass (Beloit College;Biology)

2006-05-20

16

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

17

A Concept for Blood Supply in Patients with Highly Contagious, Life-Threatening Diseases  

Microsoft Academic Search

SummaryBackground: Highly contagious, life-threatening diseases such as viral hemorrhagic fever (caused by Ebola, Marburg, Lassa or Krim-Kongo virus), orthopox virus infection, or pneumonic plague require special isolation of the patient for protection of the medical staff and the public. As blood and other body fluids from these patients may be dangerous for the laboratory staff, laboratory examinations must also be

E. Strobel; H.-U. Schmidt

2004-01-01

18

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

19

A mathematical model of the effects of chronic carriers on the within-herd spread of contagious bovine pleuropneumonia in an African mixed crop-livestock system.  

PubMed

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease of cattle; CBPP is caused by Mycoplasma mycoides subsp. mycoides small colony. CBPP is a major cause for concern for African countries (because of mortality, animal-production losses and cost of control). The clinical form of the disease is the more infectious (contagion occurs essentially through coughing). However, chronic lung lesions with viable mycoplasmas can persist in recovering cattle. Animals presenting these lesions might have a time-delimitated infectious phase. Such carriers are suspected to generate field outbreaks (although this hypothesis remains debated). We investigated the potential quantitative effects of these chronic carriers on the within-herd CBPP spread. Data were collected during a longitudinal field herd survey in a mixed crop-livestock system in the Ethiopian highlands. Two stochastic Markov-chain models' outputs (seroconversion dynamics, basic reproduction ratio R0, cumulative clinical incidence and risk of herd infection) were compared given different hypotheses on the carrier infectiousness. The late seroconversions observed in the field data were fitted correctly only for the highest carrier infectiousness we considered (mean chronic duration of 1 year and carriers 50-times less infectious than clinical cases). Although sensitivities (in terms of disease impact in the herd) were in general negligible when the carrier infectiousness was low (e.g. when carriers were assumed to be 1000-times less infectious than clinical cases), they rapidly became important when the infectiousness increased. PMID:15156997

Lesnoff, Matthieu; Laval, Géraud; Bonnet, Pascal; Chalvet-Monfray, Karine; Lancelot, Renaud; Thiaucourt, Francois

2004-02-26

20

Global Spread of Infectious Diseases  

E-print Network

We develop simple models for the global spread of infectious diseases, emphasizing human mobility via air travel and the variation of public health infrastructure from region to region. We derive formulas relating the total and peak number of infections in two countries to the rate of travel between them and their respective epidemiological parameters.

S. Hsu; A. Zee

2003-06-25

21

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

22

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

E-print Network

smallpox and plague. Smallpox and plague are contagious diseases that lead to an additional load on medical at risk. In order to properly defend against an attack involving smallpox or plague, medical planners must

Ray, Jaideep

23

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. PMID:11432812

Aitken, Celia; Jeffries, Donald J.

2001-01-01

24

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. 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.; Skj?dt, Karsten; Woods, Gregory M.; Kaufman, Jim

2013-01-01

25

Prevent the Spread of Zoonotic Diseases  

E-print Network

This small-format (4 1/4 x 5 1/2) 4-fold brochure provides details about six major ways to prevent the spread of zoonotic diseases among animals and people. Written for a general audience, it makes a great handout for youth groups working...

Pena, Josefa

2008-11-10

26

Social Distancing Strategies against Disease Spreading  

NASA Astrophysics Data System (ADS)

The recurrent infectious diseases and their increasing impact on the society has promoted the study of strategies to slow down the epidemic spreading. In this review we outline the applications of percolation theory to describe strategies against epidemic spreading on complex networks. We give a general outlook of the relation between link percolation and the susceptible-infected-recovered model, and introduce the node void percolation process to describe the dilution of the network composed by healthy individual, i.e., the network that sustain the functionality of a society. Then, we survey two strategies: the quenched disorder strategy where an heterogeneous distribution of contact intensities is induced in society, and the intermittent social distancing strategy where health individuals are persuaded to avoid contact with their neighbors for intermittent periods of time. Using percolation tools, we show that both strategies may halt the epidemic spreading. Finally, we discuss the role of the transmissibility, i.e., the effective probability to transmit a disease, on the performance of the strategies to slow down the epidemic spreading.

Valdez, L. D.; Buono, C.; Macri, P. A.; Braunstein, L. A.

2013-12-01

27

Social distancing strategies against disease spreading  

NASA Astrophysics Data System (ADS)

The recurrent infectious diseases and their increasing impact on the society has promoted the study of strategies to slow down the epidemic spreading. In this review we outline the applications of percolation theory to describe strategies against epidemic spreading on complex networks. We give a general outlook of the relation between link percolation and the susceptible-infected-recovered model, and introduce the node void percolation process to describe the dilution of the network composed by healthy individual, i.e, the network that sustain the functionality of a society. Then, we survey two strategies: the quenched disorder strategy where an heterogeneous distribution of contact intensities is induced in society, and the intermittent social distancing strategy where health individuals are persuaded to avoid contact with their neighbors for intermittent periods of time. Using percolation tools, we show that both strategies may halt the epidemic spreading. Finally, we discuss the role of the transmissibility, i.e, the effective probability to transmit a disease, on the performance of the strategies to slow down the epidemic spreading.

Valdez, L. D.; Buono, C.; Macri, P. A.; Braunstein, L. A.

2014-03-01

28

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

29

[Contagious diseases in the Austro-Hungarian Army during the First World War].  

PubMed

Before the WWI significantly more loss was caused to armies by various epidemies, than by weapons. Although as a result of development of medical sciences in the WWI this rate changed, the main epidemies namely cholera, malaria and trachoma still ravaged quite often. In spite of the fact, that alimentation of Austro-Hungarian soldiers gradually deteriorated during the war, so they fell victims more easily to diseases, the sanitary service successfully prevented outbreaks of larger epidemies. PMID:21661262

Kiss, Gábor

2010-01-01

30

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

31

Airborne Spread of Disease - The Implications for Dentistry  

Microsoft Academic Search

The potential for the airborne spread of disease has been recognized for many years. Recent studies have shown that this mode for disease transmission is capable of spreading a fatal disease such as Severe Acute Respiratory Syndrome over a wide area. Many dental procedures produce extensive aerosols and splatter that are routinely contaminated with bacteria, viruses, and blood. In the

STEPHEN K. HARREL

2004-01-01

32

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 of livestock. 167...REGULATIONS § 167.15 Control of livestock disease and introduction of livestock...and spread of contagious or infectious disease in the economic interest of the...

2011-04-01

33

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. PMID:16647974

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

2011-01-01

34

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

35

Techniques for Preventing the Spread of Infectious Diseases.  

ERIC Educational Resources Information Center

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

California State Dept. of Education, Sacramento.

36

A survey of visitors on Swedish livestock farms with reference to the spread of animal diseases  

PubMed Central

Background In addition to livestock movements, other between-farm contacts such as visitors may contribute to the spread of contagious animal diseases. Knowledge about such contacts is essential for contingency planning. Preventive measures, risk-based surveillance and contact tracing may be facilitated if the frequency and type of between-farm contacts can be assessed for different types of farms. The aim of this study was to investigate the frequency and types of visitors on farms with cloven-hoofed animals in Sweden and to analyse whether there were differences in the number of visitors attributable to region, season, and type of herd. Data were collected from Swedish farmers through contact-logs covering two-week periods during four different seasons. Results In total, 482 (32%) farmers filled in the contact log for at least one period and the data represent 18,416 days. The average number of professional and non-professional visitors per day was 0.3 and 0.8, respectively. Whereas the number of professional visitors seemed to increase with increasing herd size, this relation was not seen for non-professional visits. The mean numbers of visitors per day were highest in the summer and in the farm category ‘small mixed farm’. Reports of the visitors’ degree of contact with the animals showed that veterinarians, AI-technicians, animal transporters and neighbours were often in direct contact with the animals or entered the stables and 8.8% of the repairmen were also in direct contact with animals, which was unexpected. In a multivariable analysis, species, herd size and season were significantly associated with the number of professional visitors as well as the number of visitors in direct contact with the animals. Conclusion In conclusion there was a large variation between farms in the number and type of contacts. The number of visitors that may be more likely to spread diseases between farms was associated with animal species and herd size. PMID:24040830

2013-01-01

37

The Social Context of Foot-and-Mouth Disease Control in Texas: Foundations for Effective Risk Communication  

E-print Network

of FMD as well, helping to prevent disease spread. However, due to the complexity of moral, social, and economic issues surrounding the control of highly contagious diseases, producer cooperation during an outbreak may not be assured. This study...

Delgado, Amy Haley

2012-02-14

38

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

Code of Federal Regulations, 2011 CFR

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

2011-04-01

39

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

PubMed

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

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

2014-05-20

40

Modelling power-law spread of infectious diseases  

E-print Network

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

Meyer, Sebastian

2013-01-01

41

Should prisons ease drug prohibition to help reduce disease spread?  

PubMed

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. PMID:8943942

Kent, H

1996-11-15

42

Computational Study of Ventilation and Disease Spread in Poultry Houses  

Microsoft Academic Search

The air flow in and around poultry houses has been studied numerically with the goal of determining disease spread characteristics and comparing ventilation schemes. A typical manure-belt layer egg production facility is considered. The continuity, momentum, and energy equations are solved for flow both inside and outside poultry houses using the commercial computational fluid dynamics (CFD) code FLUENT. Both simplified

John Cimbala; Sourabh Pawar; Eileen Wheeler; Darla Lindberg

2006-01-01

43

Reducing the Spread of Infectious Disease Through Hand Washing  

Microsoft Academic Search

According to the Centers for Disease Control (2002), hand washing is the simplest, most effective measure for preventing the spread of bacteria, pathogens, and viruses. Recent studies by the American Society for Microbiology (2005) indicate that Americans do not wash their hands after going to the bathroom and before handling or eating food. The study reported here sought to determine

Marcus M. Comer; Mohammad Ibrahim

44

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. PMID:19919678

2009-01-01

45

[Care of a patient with a rare and highly contagious virus disease. An emergency situation resulted in good preparedness].  

PubMed

Ever since the eradication of smallpox, Sweden has been poorly furnished with emergency facilities for the care of patients with serious, very infectious diseases. National interest in creating such facilities was aroused by epidemics of haemorrhagic disease (first and foremost due to Ebola virus during the present decade), at the same time as the first Scandinavian case of haemorrhagic fever associated with a risk of person-to-person infection occurred in Linköping. A special laboratory which has been set up at the Centre for Disease Control, in Stockholm, and University Hospital, Linköping, in collaboration with the Board of Health and Welfare, has introduced a high-security infectious disease unit for the care of such patients, with separate ventilation and waste-water treatment systems. The unit is also equipped to provide intensive care, and a laboratory can be rapidly set up and fully operative within 12-24 hours. Most important of all, personnel are available who are trained both for laboratory work and the care of such patients, and used to working as a team and familiar with the special protective equipment. If a patient can not be transported to the special unit, a team is available to travel to the hospital where the patient has been admitted, to give instruction and help to set up infection control routines and even supply protective equipment. PMID:9411086

Frydén, A

1997-10-01

46

Airline operating realities and the global spread of infectious diseases.  

PubMed

The advent of long-haul travel in the past 10 years has considerably reduced the time of potential disease spread from one side of the world to the other. The implication for travelers is that they may unwittingly be in the prodromal phase of influenza and become symptomatic a few days after travel. Alternatively they may knowingly travel with an infectious disease by masking symptoms. This article outlines the myths that have abounded about the cabin environment being "unclean" and discusses the low likelihood of in-flight transmission with effective air-conditioning and filtration systems. The 2009 H1N1 pandemic highlighted the operational challenges of dealing with infectious disease, including the need for accurate passenger information to allow contact tracing, in contrast to futile measures such as thermal scanners. Containment attempts did not stop the rapid global spread of H1N1 influenza. PMID:20566546

Webster, Cliff H

2010-07-01

47

Spreading of diseases through comorbidity networks across life and gender  

NASA Astrophysics Data System (ADS)

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

Chmiel, Anna; Klimek, Peter; Thurner, Stefan

2014-11-01

48

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. PMID:20618897

Biek, Roman; Real, Leslie A.

2011-01-01

49

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

50

Pathways of extrapelvic spread of pelvic disease: imaging findings.  

PubMed

The complex extraperitoneal anatomy of the pelvis includes various outlets for the transit of organs and neurovascular structures to the rest of the body. These outlets include the greater sciatic foramen, lesser sciatic foramen, inguinal canal, femoral triangle, obturator canal, anal and genitourinary hiatuses of the pelvic floor, prevesical space, and iliopsoas compartment. All of these structures serve as conduits for the dissemination of malignant and benign inflammatory diseases from the pelvic cavity and into the soft-tissue structures of the abdominal wall, buttocks, and upper thigh. Knowledge of the pelvic anatomy is crucial to understand these patterns of disease spread. Cross-sectional imaging provides important anatomic information and depicts the extent of disease and its involvement of surrounding extrapelvic structures, information that is important for planning surgery and radiation therapy. PMID:21257938

Tan, Cher Heng; Vikram, Raghunandan; Boonsirikamchai, Piyaporn; Faria, Silvana C; Charnsangavej, Chusilp; Bhosale, Priya R

2011-01-01

51

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. PMID:22879600

Walker, Lary C.; LeVine, Harry

2012-01-01

52

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

2012-09-28

53

Computational Study of Ventilation and Disease Spread in Poultry Houses  

NASA Astrophysics Data System (ADS)

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

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

2006-11-01

54

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

55

The effect of opinion clustering on disease outbreaks  

E-print Network

a constant threat to the public health worldwide. Measles, a highly contagious disease caused by a virus: infectious diseases; herd immunity; clustering 1. INTRODUCTION Infectious diseases such as measles pose and thus constitute a subpopulation in which the disease can spread and cause local outbreaks

Bonhoeffer, Sebastian

56

Contagious Bovine Pleuropneumonia in Tanzania: Current Status  

Microsoft Academic Search

CBPP reappeared in Arusha, Northern Tanzania in 1990, having been introduced from Kenya. The disease spread rapidly to Mara region through rustling of sick or infected animals. In November 1992, an unrelated outbreak occurred in Kagera, having spread from Southern Uganda. Up to the end of December 1994, the disease appeared to be confined to Kagera and Arusha. In January

H. M. Msami; T. Ponela-Mlelwa; B. J. Mtei; A. M. Kapaga

2001-01-01

57

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

E-print Network

247 GIS-Based Epidemiological Modeling of an Emerging Forest Disease: Spread of Sudden Oak Death applied in a GIS to real-world wildland landscapes. In this paper, we present and evaluate a GIS model was implemented (1990-2005) in a GIS to simulate disease spread across California at a spatial

Standiford, Richard B.

58

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

Code of Federal Regulations, 2011 CFR

...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys...Procedures recommended to prevent the spread of disease by artificial insemination of turkeys...be inseminated. If evidence of active disease is noted after insemination is...

2011-01-01

59

Paramyxovirus disease in racing pigeons  

Microsoft Academic Search

Since 1981 a highly contagious viral disease causing high morbidity and low mortality in racing pigeons has spread over Europe. The virus belongs to the avian paramyxovirus sero group I. Clinical signs include watery droppings, polydypsia and neurologic signs in a high proportion of infected animals.Definitive diagnosis can be made by virus isolation in cell cultures or chicken embryos, and

J. T. Lumeij; J. W. E. Stam

1985-01-01

60

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

61

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

62

Modeling social response to the spread of an infectious disease  

E-print Network

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

Evans, Jane A. (Jane Amanda)

2012-01-01

63

Modeling spatial spread of infectious diseases with a fixed latent period in a spatially continuous domain  

E-print Network

Modeling spatial spread of infectious diseases with a fixed latent period in a spatially continuous, March 2009 Abstract In this paper, with the assumptions that an infectious disease in a population has the dynamics of infectious diseases in population level. Most continuous time models are in the form

Linder, Tamás

64

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

65

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

E-print Network

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

Britta Daudert; Bai-Lian Li

2006-11-23

66

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

2013-02-01

67

Patterns of spread of coral disease in the Florida Keys  

Microsoft Academic Search

Reefs in the Florida Keys are experiencing a dramatic increase in the number of localities and number of species with coral disease. In extensive surveys from Key Largo to Key West in 160 stations at 40 randomly chosen sites, there has been a dramatic increase in (1) the number of locations exhibiting disease (82% of all stations are now affected,

James W. Porter; Phillip Dustan; Walter C. Jaap; Kathryn L. Patterson; Vladimir Kosmynin; Ouida W. Meier; Matthew E. Patterson; Mel Parsons

2001-01-01

68

Spreading of diseases through comorbidity networks across life and gender  

E-print Network

The state of health of patients is typically not characterized by a single disease alone but by multiple (comorbid) medical conditions. These comorbidities may depend strongly on age and gender. We propose a specific phenomenological comorbidity network of human diseases that is based on medical claims data of the entire population of Austria. The network is constructed from a two-layer multiplex network, where in one layer the links represent the conditional probability for a comorbidity, and in the other the links contain the respective statistical significance. We show that the network undergoes dramatic structural changes across the lifetime of patients.Disease networks for children consist of a single, strongly inter-connected cluster. During adolescence and adulthood further disease clusters emerge that are related to specific classes of diseases, such as circulatory, mental, or genitourinary disorders.For people above 65 these clusters start to merge and highly connected hubs dominate the network. Thes...

Chmiel, Anna; Thurner, Stefan

2014-01-01

69

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

PubMed

Foot-and-mouth disease (FMD) is one of the most feared of transboundary animal diseases. Accidental or deliberate release of the causative agent can have both direct and indirect effects that result in massive economic losses and disruption. The direct effects of an FMD outbreak include immediate losses to agricultural production and disruption of local economies, while the indirect effects are mainly related to disease control measures such as restriction of market access at local and global levels and the high costs of disease control. To improve the capacity of the European Union (EU) to counter animal bioterrorism threats, AniBioThreat was launched with a special focus on threats to living animals, feed, and food of animal origin. As part of this project, several zoonotic or animal pathogenic agents are considered from different perspectives. FMD virus was selected as one agent to be scrutinized because it is highly contagious and an outbreak can have a severe economic impact. Ways to fight a deliberate outbreak can be demonstrated through the example of FMD. In this article, the virology and epidemiology of FMD virus are discussed with special attention to the related law enforcement aspects. PMID:23971796

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

2013-09-01

70

Natural human mobility patterns and spatial spread of infectious diseases  

E-print Network

We investigate a model for spatial epidemics explicitly taking into account bi-directional movements between base and destination locations on individual mobility networks. We provide a systematic analysis of generic dynamical features of the model on regular and complex metapopulation network topologies and show that significant dynamical differences exist to ordinary reaction-diffusion and effective force of infection models. On a lattice we calculate an expression for the velocity of the propagating epidemic front and find that in contrast to the diffusive systems, our model predicts a saturation of the velocity with increasing traveling rate. Furthermore, we show that a fully stochastic system exhibits a novel threshold for attack ratio of an outbreak absent in diffusion and force of infection models. These insights not only capture natural features of human mobility relevant for the geographical epidemic spread, they may serve as a starting point for modeling important dynamical processes in human and an...

Belik, Vitaly; Brockmann, Dirk

2011-01-01

71

Natural Human Mobility Patterns and Spatial Spread of Infectious Diseases  

NASA Astrophysics Data System (ADS)

We investigate a model for spatial epidemics explicitly taking into account bidirectional movements between base and destination locations on individual mobility networks. We provide a systematic analysis of generic dynamical features of the model on regular and complex metapopulation network topologies and show that significant dynamical differences exist to ordinary reaction-diffusion and effective force of infection models. On a lattice we calculate an expression for the velocity of the propagating epidemic front and find that, in contrast to the diffusive systems, our model predicts a saturation of the velocity with an increasing traveling rate. Furthermore, we show that a fully stochastic system exhibits a novel threshold for the attack ratio of an outbreak that is absent in diffusion and force of infection models. These insights not only capture natural features of human mobility relevant for the geographical epidemic spread, they may serve as a starting point for modeling important dynamical processes in human and animal epidemiology, population ecology, biology, and evolution.

Belik, Vitaly; Geisel, Theo; Brockmann, Dirk

2011-08-01

72

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. PMID:24077925

Mundt, Christopher C.; Sackett, Kathryn E.

2013-01-01

73

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.

74

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

75

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

PubMed Central

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

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

2012-01-01

76

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

PubMed Central

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

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

2010-01-01

77

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

78

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

E-print Network

An Intuitive Formulation for the Reproductive Number for the Spread of Diseases in Heterogeneous-called reproductive number and the reproductive number can provide signi#12;- cant insight into the transmission of the reproductive number and for her insightful comments and contributions in de#12;ning the reproductive number

Hyman, James "Mac"

79

An intuitive formulation for the reproductive number for the spread of diseases in heterogeneous populations  

E-print Network

An intuitive formulation for the reproductive number for the spread of diseases in heterogeneous the critical conditions for an epidemic to grow or die out. The reproductive number can provide signi appropriately for certain epidemiological models, and construct a simpli®ed formulation of the reproductive

Hyman, James "Mac"

80

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

PubMed Central

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

2011-01-01

81

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

ERIC Educational Resources Information Center

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

Fields, Cheryl M.

1987-01-01

82

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

83

Contagious Development Neighbor Interactions in Deforestation  

E-print Network

Contagious Development Neighbor Interactions in Deforestation Juan A. Robalino EfD Initiative-CATIE Alexander Pfaff Duke University October 2009 Abstract We estimate neighbor interactions in deforestation instrument for neighbors' deforestation using the slopes of neighbors' and neigh- bors' neighbors' parcels

Pfaff, Alex

84

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

85

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

Microsoft Academic Search

OBJECTIVES--To examine the effect of patient-defined non-regular heterosexual relationships on the incidence of sexually transmitted diseases and other genital infections in women and the role of condom use in the prevention of their spread. DESIGN--A cross-sectional study of sexual behaviour reported by a standardised self-administered questionnaire in new patients who presented for screening and diagnosis. SETTING--A genitourinary medicine clinic in

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

1995-01-01

86

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

PubMed

The data bases (DB) on the spread of plague, yellow fever and contagious virus hemorrhagic fevers (CVHF) in foreign countries have been created. These DB contain information on the main international air and sea ports and their relationships with natural focal territories. The data base "Sanitary control. Yellow fever" contains information on different species serving as vectors for yellow fever virus. Information on the circulation of the causative agents of Ebola fever, Lassa fever and Marburg disease in African countries has been introduced into DB, the differentiation of countries by the degree of the potential danger of the CVHF spread has been made. PMID:12524996

Prometno?, V I; Golubev, B P; Moskovitina, E A

2002-01-01

87

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

88

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

89

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

90

A Comparison between Two Simulation Models for Spread of Foot-and-Mouth Disease  

PubMed Central

Two widely used simulation models of foot-and-mouth disease (FMD) were used in order to compare the models’ predictions in term of disease spread, consequence, and the ranking of the applied control strategies, and to discuss the effect of the way disease spread is modeled on the predicted outcomes of each model. The DTU-DADS (version 0.100), and ISP (version 2.001.11) were used to simulate a hypothetical spread of FMD in Denmark. Actual herd type, movements, and location data in the period 1st October 2006 and 30th September 2007 was used. The models simulated the spread of FMD using 3 different control scenarios: 1) A basic scenario representing EU and Danish control strategies, 2) pre-emptive depopulation of susceptible herds within a 500 meters radius around the detected herds, and 3) suppressive vaccination of susceptible herds within a 1,000 meters radius around the detected herds. Depopulation and vaccination started 14 days following the detection of the first infected herd. Five thousand index herds were selected randomly, of which there were 1,000 cattle herds located in high density cattle areas and 1,000 in low density cattle areas, 1,000 swine herds located in high density swine areas and 1,000 in low density swine areas, and 1,000 sheep herds. Generally, DTU-DADS predicted larger, longer duration and costlier epidemics than ISP, except when epidemics started in cattle herds located in high density cattle areas. ISP supported suppressive vaccination rather than pre-emptive depopulation, while DTU-DADS was indifferent to the alternative control strategies. Nonetheless, the absolute differences between control strategies were small making the choice of control strategy during an outbreak to be most likely based on practical reasons. PMID:24667525

Halasa, Tariq; Boklund, Anette; Stockmarr, Anders; En?e, Claes; Christiansen, Lasse E.

2014-01-01

91

Global warming and the potential spread of vector-borne diseases  

SciTech Connect

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

Patz, J. [Johns Hopkins School of Hygiene and Public Health, Baltimore, MD (United States). Dept. of Microbiology and Immunology

1996-12-31

92

Progression of Relapsing-Remitting Demyelinating Disease Does Not Require Increased TCR Affinity or Epitope Spread.  

PubMed

In this study, we investigate the basis of T cell recognition of myelin that governs the progression from acute symptoms into disease remission, relapse, and chronic progression in a secondary progressive model of demyelinating disease. Until now, the frequency and affinity of myelin-reactive CD4 T cells that elicit relapsing-remitting disease have not been quantified. The micropipette adhesion frequency assay was used to obtain a sensitive and physiologically relevant two-dimensional measurement of frequency and TCR affinity for myelin, as the inherent low affinity does not allow the use of specific peptide:MHC-II tetramers for this purpose. We found the highest affinity and frequency of polyclonal myelin oligodendrocyte glycoprotein-reactive cells infiltrate the CNS during acute disease, whereas affinities during remission, relapse, and chronic disease are not significantly different from each other. Frequency analysis revealed that the vast majority of CNS-infiltrating CD4 T cells are myelin oligodendrocyte glycoprotein reactive at all time points, demonstrating epitope spread is not a predominant factor for disease progression. Furthermore, time points at which mice were symptomatic were characterized by an infiltration of Th17 cells in the CNS, whereas symptom remission showed an enrichment of cells producing IFN-?. Also, the ratio of regulatory T cells to Foxp3(-) CD4 T cells was significantly higher in the CNS at remission than during acute disease. The results of this study indicate that a high frequency of T cells specific for a single myelin Ag, rather than increased TCR affinity or epitope spread, governs the transition from acute symptoms through remission, relapse, and chronic disease states. PMID:25267971

Kersh, Anna E; Edwards, Lindsay J; Evavold, Brian D

2014-11-01

93

MEK-Specific Inhibitor U0126 Blocks Spread of Borna Disease Virus in Cultured Cells  

PubMed Central

Borna disease virus (BDV) is a highly neurotropic virus that causes Borna disease, a virus-induced immune-mediated encephalomyelitis, in a variety of warm-blooded animals. Recent studies reported that BDV can be detected in patients with psychiatric disorders. BDV is noncytopathic, replicates in the nucleus of infected cells, and spreads intraaxonally in vivo. Upon infection of susceptible cultured cells, virus can be detected in foci. Little is known about the cellular components required for BDV replication. Here, we show that the cellular Raf/MEK/ERK signaling cascade is activated upon infection with BDV. In the presence of the MEK-specific inhibitor U0126, cells get infected with BDV; however, there is a block in virus spread to neighboring cells. The effect of the inhibitor on virus spread was still observed when the compound was added 2 h postinfection but not if treatment was initiated as late as 4 h after infection. Our results provide new insights into the BDV-host cell interaction and show that virus infection can be controlled with drugs interfering with a cellular signaling pathway. Since concentrations of the MEK inhibitor required to block BDV focus formation are not toxic for the host cells, our finding may be important with respect to antiviral drug development. PMID:11312358

Planz, Oliver; Pleschka, Stephan; Ludwig, Stephan

2001-01-01

94

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

PubMed

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

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

2014-05-01

95

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

2012-10-01

96

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

2013-01-01

97

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. PMID:23776461

Xia, Shang; Liu, Jiming; Cheung, William

2013-01-01

98

The spread of infectious diseases via air travel illustrates how the global connectivity of a man-made system like the air transporta-  

E-print Network

PROBLEM The spread of infectious diseases via air travel illustrates how the global connectivity to spread an infectious disease that begins at that airport, and found that traffic and connectivity alone

Entekhabi, Dara

99

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

NASA Astrophysics Data System (ADS)

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

Barbera, Elvira; Consolo, Giancarlo; Valenti, Giovanna

2013-11-01

100

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

...INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE LIVESTOCK IMPROVEMENT AUXILIARY PROVISIONS ON NATIONAL POULTRY IMPROVEMENT PLAN Sanitation Procedures § 147.27 Procedures recommended to prevent the spread of disease by artificial insemination of...

2014-01-01

101

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

PubMed

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

Baron, R C; McCormick, J B; Zubeir, O A

1983-01-01

102

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

PubMed Central

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

Plorde, D S

1981-01-01

103

Molecular drivers and cortical spread of lateral entorhinal cortex dysfunction in preclinical Alzheimer’s disease  

PubMed Central

The entorhinal cortex has been implicated in the early stages of Alzheimer’s disease, which is characterized by changes in the tau protein and in the cleaved fragments of the amyloid precursor protein (APP). We used a high-resolution functional magnetic resonance imaging (fMRI) variant that can map metabolic defects in patients and mouse models to address basic questions about entorhinal cortex pathophysiology. The entorhinal cortex is divided into functionally distinct regions, the medial entorhinal cortex (MEC) and the lateral entorhinal cortex (LEC), and we exploited the high-resolution capabilities of the fMRI variant to ask whether either of them was affected in patients with preclinical Alzheimer’s disease. Next, we imaged three mouse models of disease to clarify how tau and APP relate to entorhinal cortex dysfunction and to determine whether the entorhinal cortex can act as a source of dysfunction observed in other cortical areas. We found that the LEC was affected in preclinical disease, that LEC dysfunction could spread to the parietal cortex during preclinical disease and that APP expression potentiated tau toxicity in driving LEC dysfunction, thereby helping to explain regional vulnerability in the disease. PMID:24362760

Khan, Usman A; Liu, Li; Provenzano, Frank A; Berman, Diego E; Profaci, Caterina P; Sloan, Richard; Mayeux, Richard; Duff, Karen E; Small, Scott A

2014-01-01

104

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

NASA Astrophysics Data System (ADS)

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

Upadhyay, Ranjit Kumar; Roy, Parimita

2014-12-01

105

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

106

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

PubMed Central

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

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

2014-01-01

107

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

PubMed

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

Risau-Gusman, Sebastián

2012-06-01

108

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

PubMed Central

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

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

2014-01-01

109

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. PMID:19740888

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

2009-01-01

110

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

PubMed Central

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

Sellers, R. F.

1980-01-01

111

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

PubMed

Sexually transmitted pathogens persist in populations despite the availability of biomedical interventions and knowledge of behavioural changes that would reduce individual-level risk. While behavioural risk factors are shared between many sexually transmitted infections, the prevalence of these diseases across different risk groups varies. Understanding this heterogeneity and identifying better control strategies depends on an improved understanding of the complex social contact networks over which pathogens spread. To date, most efforts to study the impact of sexual network structure on disease dynamics have focused on static networks. However, the interaction between the dynamics of partnership formation and dissolution and the dynamics of transmission plays a role, both in restricting the effective network accessible to the pathogen, and in modulating the transmission dynamics. We present a simple method to simulate dynamical networks of sexual partnerships. We inform the model using survey data on sexual attitudes and lifestyles, and investigate how the duration of infectiousness changes the effective contact network over which disease may spread. We then simulate several control strategies: screening, vaccination and behavioural interventions. Previous theory and research has advanced the importance of core groups for spread and control of STD. Our work is consistent with the importance of core groups, but extends this idea to consider how the duration of infectiousness associated with a particular pathogen interacts with host behaviours to define these high risk subpopulations. Characteristics of the parts of the network accessible to the pathogen, which represent the network structure of sexual contacts from the "point of view" of the pathogen, are substantially different from those of the network as a whole. The pathogen itself plays an important role in determining this effective network structure; specifically, we find that if the pathogen's duration of infectiousness is short, infection is more concentrated in high-activity, high-concurrency individuals even when all other factors are held constant. Widespread screening programmes 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. PMID:22248701

Robinson, Katy; Cohen, Ted; Colijn, Caroline

2012-03-01

112

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. PMID:22248701

Robinson, Katy; Cohen, Ted; Colijn, Caroline

2012-01-01

113

Analytical methods for quantifying environmental connectivity for the control and surveillance of infectious disease spread  

PubMed Central

The sustained transmission and spread of environmentally mediated infectious diseases is governed in part by the dispersal of parasites, disease vectors and intermediate hosts between sites of transmission. Functional geospatial models can be used to quantify and predict the degree to which environmental features facilitate or limit connectivity between target populations, yet typical models are limited in their geographical and analytical approach, providing simplistic, global measures of connectivity and lacking methods to assess the epidemiological implications of fine-scale heterogeneous landscapes. Here, functional spatial models are applied to problems of surveillance and control of the parasitic blood fluke Schistosoma japonicum and its intermediate snail host Oncomelania haupensis in western China. We advance functional connectivity methods by providing an analytical framework to (i) identify nodes of transmission where the degree of connectedness to other villages, and thus the potential for disease spread, is higher than is estimated using Euclidean distance alone and (ii) (re)organize transmission sites into disease surveillance units based on second-order relationships among nodes using non-Euclidean distance measures, termed effective geographical distance (EGD). Functional environmental models are parametrized using ecological information on the target organisms, and pair-wise distributions of inter-node EGD are estimated. A Monte Carlo rank product analysis is presented to identify nearby nodes under alternative distance models. Nodes are then iteratively embedded into EGD space and clustered using a k-means algorithm to group villages into ecologically meaningful surveillance groups. A consensus clustering approach is taken to derive the most stable cluster structure. The results indicate that novel relationships between nodes are revealed when non-Euclidean, ecologically determined distance measures are used to quantify connectivity in heterogeneous landscapes. These connections are not evident when analysing nodes in Euclidean space, and thus surveillance and control activities planned using Euclidean distance measures may be suboptimal. The methods developed here provide a quantitative framework for assessing the effectiveness of ecologically grounded surveillance systems and of control and prevention strategies for environmentally mediated diseases. PMID:20164085

Remais, Justin; Akullian, Adam; Ding, Lu; Seto, Edmund

2010-01-01

114

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

PubMed Central

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

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

2012-01-01

115

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

PubMed

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. PMID:22322159

Vernon, Matthew C; Keeling, Matt J

2012-06-01

116

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. PMID:22322159

Vernon, Matthew C.; Keeling, Matt J.

2012-01-01

117

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

PubMed

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

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

2012-06-13

118

Representative contact diaries for modeling the spread of infectious diseases in Taiwan.  

PubMed

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

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

2012-01-01

119

Constraints to the integration of the contagious caprine pleuropneumonia (CCPP) vaccine into Kenya's animal health delivery system  

Microsoft Academic Search

Animal health is key to successful livestock production in developing countries. The development and delivery of vaccines against major epidemic diseases is one component of improving animal health. This paper presents a case study from Kenya on the production and delivery of a vaccine against Contagious Caprine Pleuropneumonia (CCPP), a major disease of goats. The vaccine, while technically a viable

Michele E. Lipner; Ralph B. Brown

1995-01-01

120

Laboratory generation of new parthenogenetic lineages supports contagious parthenogenesis in Artemia  

PubMed Central

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

Amat, Francisco; Hontoria, Francisco; Gomez, Africa

2014-01-01

121

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

PubMed

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

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

2014-08-01

122

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

PubMed

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

Bartholomew, Alex J; Cirulli, Elizabeth T

2014-01-01

123

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

PubMed Central

All great ape species are endangered, and infectious diseases are thought to pose a particular threat to their survival. As great ape species vary substantially in social organisation and gregariousness, there are likely to be differences in susceptibility to disease types and spread. Understanding the relation between social variables and disease is therefore crucial for implementing effective conservation measures. Here, we simulate the transmission of a range of diseases in a population of orang-utans in Sabangau Forest (Central Kalimantan) and a community of chimpanzees in Budongo Forest (Uganda), by systematically varying transmission likelihood and probability of subsequent recovery. Both species have fission-fusion social systems, but differ considerably in their level of gregariousness. We used long-term behavioural data to create networks of association patterns on which the spread of different diseases was simulated. We found that chimpanzees were generally far more susceptible to the spread of diseases than orang-utans. When simulating different diseases that varied widely in their probability of transmission and recovery, it was found that the chimpanzee community was widely and strongly affected, while in orang-utans even highly infectious diseases had limited spread. Furthermore, when comparing the observed association network with a mean-field network (equal contact probability between group members), we found no major difference in simulated disease spread, suggesting that patterns of social bonding in orang-utans are not an important determinant of susceptibility to disease. In chimpanzees, the predicted size of the epidemic was smaller on the actual association network than on the mean-field network, indicating that patterns of social bonding have important effects on susceptibility to disease. We conclude that social networks are a potentially powerful tool to model the risk of disease transmission in great apes, and that chimpanzees are particularly threatened by infectious disease outbreaks as a result of their social structure. PMID:24740263

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

2014-01-01

124

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

NASA Astrophysics Data System (ADS)

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

Holme, Petter; Liljeros, Fredrik

2014-05-01

125

Hand, Foot and Mouth Disease in China: Patterns of Spread and Transmissibility during 2008-2009  

PubMed Central

Background Large outbreaks of hand, foot and mouth disease (HFMD) were observed in both 2008 and 2009 in China. Methods Using the national surveillance data since May 2, 2008, epidemiological characteristics of the outbreaks are summarized, and the transmissibility of the disease and the effects of potential risk factors were evaluated via a susceptible-infectious-recovered transmission model. Results Children of 1.0–2.9 years were the most susceptible group to HFMD (odds ratios [OR] > 2.3 as compared to other age groups). Infant cases had the highest incidences of severe disease (ORs > 1.4) and death (ORs > 2.4), as well as the longest delay from symptom onset to diagnosis (2.3 days). Males were more susceptible to HFMD than females (OR=1.56 [95% confidence interval=1.56, 1.57]). An one day delay in diagnosis was associated with increases in the odds of severe disease by 40.3% [38.7%, 41.9%] and in the odds of death by 53.7% [43.6%, 64.5%]. Compared to Coxsackie A16, enterovirus (EV) 71 is more strongly associated with severe disease (OR=15.6 [13.4, 18.1]) and death (OR=40.7 [13.0, 127.3]). The estimated local effective reproductive numbers among prefectures ranged from 1.4 to 1.6 (median=1.4) in spring and stayed below 1.2 in other seasons. A higher risk of transmission was associated with temperatures in the range of 70-80F, higher relative humidity, wind speed, precipitation, population density, and the periods in which schools were open. Conclusion HFMD is a moderately transmittable infectious disease, mainly among pre-school children. EV71 was responsible for most severe cases and fatalities. Mixing of asymptomatically infected children in schools might have contributed to the spread of HFMD. Timely diagnosis may be a key to reducing the high mortality rate in infants. PMID:21968769

Wang, Yu; Feng, Zijian; Yang, Yang; Self, Steve; Gao, Yongjun; Longini, Ira M.; Wakefield, Jon; Zhang, Jing; Wang, Liping; Chen, Xi; Yao, Lena; Stanaway, Jeffrey D.; Wang, Zijun; Yang, Weizhong

2011-01-01

126

Functional role of epitope spreading in the chronic pathogenesis of autoimmune and virus-induced demyelinating diseases.  

PubMed

These results support a model of epitope spreading (Figure 4) wherein localized virus-specific T cell-mediated inflammatory processes lead to the recruitment/activation of CNS-resident APCs which can serve both as effector cells for myelin destruction and as APCs which efficiently process/present endogenous self epitopes to autoreactive T cells. Thus, inflammatory responses induced by viruses which trigger pro-inflammatory Th1 responses and have the ability to persist in genetically susceptible hosts, may lead to chronic organ-specific autoimmune disease via epitope spreading. Regardless of the specificity of the T cells (myelin peptides in R-EAE or TMEV epitopes in TMEV-IDD) responsible for initiating myelin destruction, epitope spreading plays an important contributory role in the chronic disease process in genetically susceptible SJL mice. Epitope spreading has obvious important implications to the design of antigen-specific therapies for the potential treatment of MS and other autoimmune diseases. This process indicates that autoimmune diseases are evolving pathologies and that the specificity of the effector autoantigen-specific T cells varies during the chronic disease process. PMID:11505979

Miller, S D; Eagar, T N

2001-01-01

127

Heart Disease  

MedlinePLUS

... chest pain, heart attacks, and strokes . What Is Heart Disease? The heart is the center of the ... burst blood vessel. Continue How Do You Get Heart Disease? Heart disease isn't contagious — you can' ...

128

Herpes Simplex Virus Type 1 Glycoprotein E Domains Involved in Virus Spread and Disease  

Microsoft Academic Search

Herpes simplex virus type 1 (HSV-1) glycoprotein E (gE) functions as an immunoglobulin G (IgG) Fc bind- ing protein and is involved in virus spread. Previously we studied a gE mutant virus that was impaired for IgG Fc binding but intact for spread and another that was normal for both activities. To further evaluate the role of gE in spread,

CHARLES E. SALDANHA; JOHN LUBINSKI; CLAUDIA MARTIN; THANDAVARAYAN NAGASHUNMUGAM; LIYANG WANG; HARJEET VAN DER KEYL; RUTH TAL-SINGER; HARVEY M. FRIEDMAN

2000-01-01

129

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

130

Contagious Yawning and Seasonal Climate Variation  

PubMed Central

Recent evidence suggests that yawning is a thermoregulatory behavior. To explore this possibility further, the frequency of contagious yawning in humans was measured while outdoors in a desert climate in the United States during two distinct temperature ranges and seasons (winter: 22°C; early summer: 37°C). As predicted, the proportion of pedestrians who yawned in response to seeing pictures of people yawning differed significantly between the two conditions (winter: 45%; summer: 24%). Across conditions yawning occurred at lower ambient temperatures, and the tendency to yawn during each season was associated with the length of time spent outside prior to being tested. Participants were more likely to yawn in the milder climate after spending long periods of time outside, while prolonged exposure to ambient temperatures at or above body temperature was associated with reduced yawning. This is the first report to show that the incidence of yawning in humans is associated with seasonal climate variation, further demonstrating that yawn-induced contagion effects can be mediated by factors unrelated to individual social characteristics or cognitive development. PMID:21960970

Gallup, Andrew C.; Eldakar, Omar Tonsi

2011-01-01

131

Efficient detection of contagious outbreaks in massive metropolitan encounter networks  

E-print Network

Physical contact remains difficult to trace in large metropolitan networks, though it is a key vehicle for the transmission of contagious outbreaks. Co-presence encounters during daily transit use provide us with a city-scale ...

Sun, Lijun

132

Bioeconomic modeling of intervention against clinical mastitis caused by contagious pathogens.  

PubMed

The objective of this study was to assess the epidemiologic and economic consequences of intervention against contagious clinical mastitis during lactation. A bioeconomic model of intramammary infections (IMI) was used to simulate contagious spread of Staphylococcus aureus, Streptococcus uberis, and Streptococcus dysgalactiae, and an environmental spread of Escherichia coli IMI in a 100-cow dairy herd during 1 quota year. The costs of clinical IMI, subclinical IMI, and intervention were calculated into the total annual net costs of IMI during lactation per scenario and compared with a default scenario. Input parameter values were based on the scientific literature. The scenarios were 3-d intramammary lactational treatment (default), 5-d intramammary treatment, 5-d intramammary treatment and 3-d systemic treatment, 3-d intramammary treatment and culling bacteriologically unrecovered clinical IMI cows, and 5-d intramammary treatment and culling bacteriologically unrecovered clinical IMI cows. Sensitivity analysis was conducted on parameter input values. The results showed that interventions including antibiotic treatment combined with culling unrecovered clinical IMI cows resulted in the lowest transmission, number of IMI cases, and persistent subclinical IMI cases. Nonetheless, the high associated costs of culling bacteriologically unrecovered clinical IMI cows made the other scenarios with a long and intensive antibiotic treatment, but without culling, the most cost effective. The model was sensitive to changes to the cure rate of clinical IMI following treatment, but the ranking of the intervention scenarios did not change. The model was most sensitive to the changes to the transmission rate of Staph. aureus. The ranking of the intervention scenarios changed at low transmission rate of this pathogen, in which the default scenario became the most cost-effective scenario. In case of high transmission of contagious IMI pathogens, long and intensive treatment of clinical IMI should be preceded by strategies that lower the transmission. PMID:22863098

Halasa, T

2012-10-01

133

Commuter Mobility and the Spread of Infectious Diseases: Application to Influenza in France  

PubMed Central

Commuting data is increasingly used to describe population mobility in epidemic models. However, there is little evidence that the spatial spread of observed epidemics agrees with commuting. Here, using data from 25 epidemics for influenza-like illness in France (ILI) as seen by the Sentinelles network, we show that commuting volume is highly correlated with the spread of ILI. Next, we provide a systematic analysis of the spread of epidemics using commuting data in a mathematical model. We extract typical paths in the initial spread, related to the organization of the commuting network. These findings suggest that an alternative geographic distribution of GP accross France to the current one could be proposed. Finally, we show that change in commuting according to age (school or work commuting) impacts epidemic spread, and should be taken into account in realistic models. PMID:24416152

Charaudeau, Segolene; Pakdaman, Khashayar; Boelle, Pierre-Yves

2014-01-01

134

Commuter mobility and the spread of infectious diseases: application to influenza in France.  

PubMed

Commuting data is increasingly used to describe population mobility in epidemic models. However, there is little evidence that the spatial spread of observed epidemics agrees with commuting. Here, using data from 25 epidemics for influenza-like illness in France (ILI) as seen by the Sentinelles network, we show that commuting volume is highly correlated with the spread of ILI. Next, we provide a systematic analysis of the spread of epidemics using commuting data in a mathematical model. We extract typical paths in the initial spread, related to the organization of the commuting network. These findings suggest that an alternative geographic distribution of GP accross France to the current one could be proposed. Finally, we show that change in commuting according to age (school or work commuting) impacts epidemic spread, and should be taken into account in realistic models. PMID:24416152

Charaudeau, Segolene; Pakdaman, Khashayar; Boëlle, Pierre-Yves

2014-01-01

135

Social network sensors for early detection of contagious outbreaks.  

PubMed

Current methods for the detection of contagious outbreaks give contemporaneous information about the course of an epidemic at best. It is known that individuals near the center of a social network are likely to be infected sooner during the course of an outbreak, on average, than those at the periphery. Unfortunately, mapping a whole network to identify central individuals who might be monitored for infection is typically very difficult. We propose an alternative strategy that does not require ascertainment of global network structure, namely, simply monitoring the friends of randomly selected individuals. Such individuals are known to be more central. To evaluate whether such a friend group could indeed provide early detection, we studied a flu outbreak at Harvard College in late 2009. We followed 744 students who were either members of a group of randomly chosen individuals or a group of their friends. Based on clinical diagnoses, the progression of the epidemic in the friend group occurred 13.9 days (95% C.I. 9.9-16.6) in advance of the randomly chosen group (i.e., the population as a whole). The friend group also showed a significant lead time (p<0.05) on day 16 of the epidemic, a full 46 days before the peak in daily incidence in the population as a whole. This sensor method could provide significant additional time to react to epidemics in small or large populations under surveillance. The amount of lead time will depend on features of the outbreak and the network at hand. The method could in principle be generalized to other biological, psychological, informational, or behavioral contagions that spread in networks. PMID:20856792

Christakis, Nicholas A; Fowler, James H

2010-01-01

136

Social Network Sensors for Early Detection of Contagious Outbreaks  

PubMed Central

Current methods for the detection of contagious outbreaks give contemporaneous information about the course of an epidemic at best. It is known that individuals near the center of a social network are likely to be infected sooner during the course of an outbreak, on average, than those at the periphery. Unfortunately, mapping a whole network to identify central individuals who might be monitored for infection is typically very difficult. We propose an alternative strategy that does not require ascertainment of global network structure, namely, simply monitoring the friends of randomly selected individuals. Such individuals are known to be more central. To evaluate whether such a friend group could indeed provide early detection, we studied a flu outbreak at Harvard College in late 2009. We followed 744 students who were either members of a group of randomly chosen individuals or a group of their friends. Based on clinical diagnoses, the progression of the epidemic in the friend group occurred 13.9 days (95% C.I. 9.9–16.6) in advance of the randomly chosen group (i.e., the population as a whole). The friend group also showed a significant lead time (p<0.05) on day 16 of the epidemic, a full 46 days before the peak in daily incidence in the population as a whole. This sensor method could provide significant additional time to react to epidemics in small or large populations under surveillance. The amount of lead time will depend on features of the outbreak and the network at hand. The method could in principle be generalized to other biological, psychological, informational, or behavioral contagions that spread in networks. PMID:20856792

Christakis, Nicholas A.; Fowler, James H.

2010-01-01

137

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

NASA Astrophysics Data System (ADS)

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

Stone, Thomas E., Jr.

138

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

PubMed

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

Siddle, Hannah V; Kaufman, Jim

2013-09-01

139

Lyme Disease  

MedlinePLUS Videos and Cool Tools

... nodes. They divide and multiply and produce harmful substances called toxins. Lyme disease is not contagious. . Symptoms ... nodes. They divide and multiply and produce harmful substances called toxins. Lyme disease can also affect the ...

140

Using Friends as Sensors to Detect Global-Scale Contagious Outbreaks  

PubMed Central

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

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

2014-01-01

141

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

PubMed

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

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

2014-01-01

142

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

E-print Network

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

Benjamin, Ivorra; Diène, Ngom

2014-01-01

143

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

NASA Astrophysics Data System (ADS)

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

Huq, A.; Colwell, R.

2011-12-01

144

The Earth Institute, Columbia University18 19 the spread of many diseases in africa  

E-print Network

temperatures warm. Bacterial meningitis can spread rapidly in the dusty dry season in the semi-arid belt in insecticide to kill mosquitoes or stockpiling meningitis vaccine. "Seasonal forecasting is not just gauges. Malaria and meningitis alone kill thousands of people each year across sub-Saharan Africa

145

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

146

Influence of vectors' risk-spreading strategies and environmental stochasticity on the epidemiology and evolution of vector-borne diseases: the example of Chagas' disease.  

PubMed

Insects are known to display strategies that spread the risk of encountering unfavorable conditions, thereby decreasing the extinction probability of genetic lineages in unpredictable environments. To what extent these strategies influence the epidemiology and evolution of vector-borne diseases in stochastic environments is largely unknown. In triatomines, the vectors of the parasite Trypanosoma cruzi, the etiological agent of Chagas' disease, juvenile development time varies between individuals and such variation most likely decreases the extinction risk of vector populations in stochastic environments. We developed a simplified multi-stage vector-borne SI epidemiological model to investigate how vector risk-spreading strategies and environmental stochasticity influence the prevalence and evolution of a parasite. This model is based on available knowledge on triatomine biodemography, but its conceptual outcomes apply, to a certain extent, to other vector-borne diseases. Model comparisons between deterministic and stochastic settings led to the conclusion that environmental stochasticity, vector risk-spreading strategies (in particular an increase in the length and variability of development time) and their interaction have drastic consequences on vector population dynamics, disease prevalence, and the relative short-term evolution of parasite virulence. Our work shows that stochastic environments and associated risk-spreading strategies can increase the prevalence of vector-borne diseases and favor the invasion of more virulent parasite strains on relatively short evolutionary timescales. This study raises new questions and challenges in a context of increasingly unpredictable environmental variations as a result of global climate change and human interventions such as habitat destruction or vector control. PMID:23951018

Pelosse, Perrine; Kribs-Zaleta, Christopher M; Ginoux, Marine; Rabinovich, Jorge E; Gourbière, Sébastien; Menu, Frédéric

2013-01-01

147

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

PubMed

Emerging diseases (ED) can have devastating effects on agriculture. Consequently, agricultural insurance for ED can develop if basic insurability criteria are met, including the capability to estimate the severity of ED outbreaks with associated uncertainty. The U.S. farm-raised channel catfish (Ictalurus punctatus) industry was used to evaluate the feasibility of using a disease spread simulation modeling framework to estimate the potential losses from new ED for agricultural insurance purposes. Two stochastic models were used to simulate the spread of ED between and within channel catfish ponds in Mississippi (MS) under high, medium, and low disease impact scenarios. The mean (95% prediction interval (PI)) proportion of ponds infected within disease-impacted farms was 7.6% (3.8%, 22.8%), 24.5% (3.8%, 72.0%), and 45.6% (4.0%, 92.3%), and the mean (95% PI) proportion of fish mortalities in ponds affected by the disease was 9.8% (1.4%, 26.7%), 49.2% (4.7%, 60.7%), and 88.3% (85.9%, 90.5%) for the low, medium, and high impact scenarios, respectively. The farm-level mortality losses from an ED were up to 40.3% of the total farm inventory and can be used for insurance premium rate development. Disease spread modeling provides a systematic way to organize the current knowledge on the ED perils and, ultimately, use this information to help develop actuarially sound agricultural insurance policies and premiums. However, the estimates obtained will include a large amount of uncertainty driven by the stochastic nature of disease outbreaks, by the uncertainty in the frequency of future ED occurrences, and by the often sparse data available from past outbreaks. PMID:23560798

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

2013-10-01

148

Protest: Random or Contagious?The Postwar United Kingdom  

Microsoft Academic Search

This paper tests the argument that outbreaks of protest occur contagiously over time against the alternative expectation that protest occurs randomly over time. Using univariate ARIMA models, it analyzes a time series of protest in the postwar United Kingdom, consisting of the number of day\\/locales of protest events. The (logged) data are probed for three periods of temporal aggregation: annual,

Mark Lichbach

1985-01-01

149

Contagious ecthyma in mountain goat of coastal British Columbia.  

PubMed

Contagious ecthyma has been reported previously from mountain goat (Oreamnos americanus) in one restricted area of eastern British Columbia. A second focus of infection is reported for mountain goat from western British Columbia. Diagnosis was based on appearance of lesions at necropsy, histopathology and demonstration of poxvirus with the electron microscope. The epizootiology of this infection in mountain goat is discussed briefly. PMID:559107

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

1977-04-01

150

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

PubMed

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

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

2013-12-01

151

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

PubMed Central

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

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

2013-01-01

152

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

2013-01-01

153

Lognormal Infection Times of Online Information Spread  

PubMed Central

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

2013-01-01

154

Intercontinental Spread of a Genetically Distinctive Complex of Clones of Neisseria meningitidis Causing Epidemic Disease  

Microsoft Academic Search

Strains of Neisseria meningitidis responsible for an epidemic of meningococcal disease occurring in Norway since the mid-1970s and for recent increases in the incidence of disease in several other parts of Europe have been identified by multilocus enzyme electrophoresis as members of a distinctive group of 22 closely related clones (the ET-5 complex). Clones of this complex have also colonized

Dominique A. Caugant; L. Oddvar Froholm; Kjell Bovre; Eirik Holten; Carl E. Frasch; Louis F. Mocca; Wendell D. Zollinger; Robert K. Selander

1986-01-01

155

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

PubMed

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

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

2014-11-01

156

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

2013-10-01

157

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

PubMed

SUMMARY Meningococcal serogroup W strains have been emerging throughout the current century with most of the isolates belonging to the sequence type (ST11)/electrophoretic type (ET37) clonal complex (ST11/E37 CC), particularly since the international outbreak following Hajj 2000. That outbreak appears to have triggered off that trend, contributing to the spread of W ST11/ET37 CC strains globally; however, local strains could be also responsible for increases in the percentage and/or incidence rates of this serogroup in some countries. More recently, unexpected increases in the percentage and incidence rate of W has been noticed in different countries located in the South Cone in Latin America, and W ST11/ET37 CC strains now appear as endemic in the region and an extensive immunization programme with tetravalent conjugate vaccine (covering serogroups A, C, Y and W) has been recently implemented in Chile. It is difficult to ascertain whether we are observing the emergence of W ST11 CC strains in different geographical areas or whether the Hajj 2000 strain is still spreading globally. Several aspects of the evolution of that situation are analysed in this paper, reviewing also the implications in immunization programmes. Closely related with the analysis of this potential evolution, it will be very interesting to monitor the evolution of serogroup W in the African meningitis belt after implementation of the extensive immunization programme with serogroup A conjugate vaccine that is currently underway. More data about carriers, transmission, clonal lineages, etc. are needed for taking decisions (target groups, outbreak control, defining the extent, etc.) to adapt the response strategy with potential interventions with broad coverage vaccines against the emergent serogroup W. PMID:24831052

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

2014-12-01

158

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

PubMed

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

Kumar, Amit; Rahal, Anu; Chakraborty, Sandip; Verma, Amit Kumar; Dhama, Kuldeep

2014-01-01

159

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

PubMed Central

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

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

2009-01-01

160

Infectious Disease and Climate Change: Is Climate Change Responsible for the Spread of West Nile Virus?  

NSDL National Science Digital Library

Temperature increases associated with global climate change have led to concerns that infectious diseases common in warmer tropical and subtropical climates may become more common in warming middle altitudes. In this problem-based learning module, learners investigate the connections between disease and climate change. Additional resources and activities are also provided. This module was developed to be used in the Earth System Science Education Alliance (ESSEA) courses for middle and high school teachers and is also available to teachers to adapt for general classroom use.

161

Presence of Contagious Yawning in Children with Autism Spectrum Disorder  

PubMed Central

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

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

2013-01-01

162

Using mobile phone call data records for modelling infectious disease spread  

E-print Network

Department of Health and a mobile phone provider, Simin, Social interactions are a major driver of epidemics-going collaborations with the mobile phone service provider as well as the Department of Health in Iceland. The student Using mobile phone call data records for modelling infectious disease

Wright, Francis

163

Personalized ventilation as a control measure for airborne transmissible disease spread.  

PubMed

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. PMID:19812074

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

2009-12-01

164

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. PMID:19812074

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

2009-01-01

165

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

2013-05-01

166

Assessing biosecurity practices, movements and densities of poultry sites across Belgium, resulting in different farm risk-groups for infectious disease introduction and spread  

Microsoft Academic Search

The existing diversity within poultry systems affects the potential risk of infectious disease introduction and spread. Population data on the level of biosecurity and between-farm contacts is scarce, despite its importance for identifying possible routes of disease transmission. A study was carried out in Belgium to investigate and differentiate professional and hobby poultry sites based on their biosecurity levels and

Sarah Van Steenwinkel; Stefaan Ribbens; Els Ducheyne; Els Goossens; Jeroen Dewulf

2011-01-01

167

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

E-print Network

and in the context of political, economic and social pressures. Disease spread models can be used to evaluate the design of optimal control strategies, for policy formulation, for gap analysis and to develop and refine research agendas when disease is not present...

Highfield, Linda

2009-05-15

168

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

169

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

170

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. PMID:21935357

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

171

Long-Distance Travel Behaviours Accelerate and Aggravate the Large-Scale Spatial Spreading of Infectious Diseases  

PubMed Central

The study analyses the role of long-distance travel behaviours on the large-scale spatial spreading of directly transmitted infectious diseases, focusing on two different travel types in terms of the travellers travelling to a specific group or not. For this purpose, we have formulated and analysed a metapopulation model in which the individuals in each subpopulation are organised into a scale-free contact network. The long-distance travellers between the subpopulations will temporarily change the network structure of the destination subpopulation through the “merging effects (MEs),” which indicates that the travellers will be regarded as either connected components or isolated nodes in the contact network. The results show that the presence of the MEs has constantly accelerated the transmission of the diseases and aggravated the outbreaks compared to the scenario in which the diversity of the long-distance travel types is arbitrarily discarded. Sensitivity analyses show that these results are relatively constant regarding a wide range variation of several model parameters. Our study has highlighted several important causes which could significantly affect the spatiotemporal disease dynamics neglected by the present studies. PMID:24511324

Zu, Zhenghu; Zheng, Tao; Zhang, Wendou; Xu, Qing; Liu, Jinjie

2014-01-01

172

Bioeconomic modeling of lactational antimicrobial treatment of new bovine subclinical intramammary infections caused by contagious pathogens.  

PubMed

This study determined the direct and indirect epidemiologic and economic effects of lactational treatment of new bovine subclinical intramammary infections (IMI) caused by contagious pathogens using an existing bioeconomic model. The dynamic and stochastic model simulated the dynamics of Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, and Escherichia coli during lactation and the dry period in a 100-cow dairy herd during 1 quota year. Input parameters on cure were obtained from recent Dutch field data. The costs of clinical IMI, subclinical IMI, and intervention were calculated into the combined total annual net costs of IMI per herd. The cost effectiveness of 4 scenarios with lactational intervention was determined; scenarios included no intervention, treatment after 1 mo of infection, treatment after 2 mo of infection, and treatment after 1 mo of infection and culling of uncured cows after 2 mo of infection. Model behavior was observed for variation in parameter input values. Compared with no lactational intervention, lactational intervention of new subclinical IMI resulted in fewer clinical flare ups, less transmission within the herd, and much lower combined total annual net costs of IMI in dairy herds. Antimicrobial treatment of IMI after 1 mo of infection and culling of uncured cows after 2 mo of infection resulted in the lowest costs, whereas treatment after 2 mo of infection was associated with the highest costs between the scenarios with intervention. Changing the probability of cure resulted in a nonlinear change in the cumulative incidence of IMI cases and associated costs. Lactational treatment was able to prevent IMI epidemics in dairy herds at high transmission rates of Strep. uberis, Strep. dysgalactiae, and E. coli. Lactational treatment did not limit the spread of Staph. aureus at high transmission rates, although the associated costs were lower compared with no intervention. To improve udder health in a dairy herd, lactational treatment of contagious subclinical IMI must therefore be preceded by management measures that lower the transmission rate. Lactational treatment of environmental subclinical IMI seemed less cost effective. Detection of subclinical IMI needs improvement to be able to most effectively treat subclinical IMI caused by contagious pathogens during lactation. PMID:20723677

van den Borne, B H P; Halasa, T; van Schaik, G; Hogeveen, H; Nielen, M

2010-09-01

173

Beech bark disease: spatial patterns of thicket formation and disease spread in an aftermath forest in the northeastern  

E-print Network

in the Adirondack Mountains of New York using location and disease severity of beech trees. A bivariate point northern hardwood forests of North America. Key words: Adirondack Mountains, American beech, BBD, beech� dans les monts Adirondack, dans l'�tat de New York, en utilisant la position des h�tres et la s

Mountrakis, Giorgos

174

Molecular evolutionary signatures reveal the role of host ecological dynamics in viral disease emergence and spread  

PubMed Central

RNA viruses account for numerous emerging and perennial infectious diseases, and are characterized by rapid rates of molecular evolution. The ecological dynamics of most emerging RNA viruses are still poorly understood and difficult to ascertain. The availability of genome sequence data for many RNA viruses, in principle, could be used to infer ecological dynamics if changes in population numbers produced a lasting signature within the pattern of genome evolution. As a result, the rapidly emerging phylogeographic structure of a pathogen, shaped by the rise and fall in the number of infections and their spatial distribution, could be used as a surrogate for direct ecological assessments. Based on rabies virus as our example, we use a model combining ecological and evolutionary processes to test whether variation in the rate of host movement results in predictive diagnostic patterns of pathogen genetic structure. We identify several linearizable relationships between host dispersal rate and measures of phylogenetic structure suggesting genetic information can be used to directly infer ecological process. We also find phylogenetic structure may be more revealing than demography for certain ecological processes. Our approach extends the reach of current analytic frameworks for infectious disease dynamics by linking phylogeography back to underlying ecological processes. PMID:23382419

Duke-Sylvester, Scott M.; Biek, Roman; Real, Leslie A.

2013-01-01

175

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. PMID:23864792

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

2013-01-01

176

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

177

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

178

Contagious Yawning and the Frontal Lobe: An fMRI Study  

PubMed Central

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:20357471

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

2014-01-01

179

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

PubMed

Contagious ecthyma (CE) is reported in bighorn sheep (Ovis c. canadensis) from several national parks in western Canada and in moutain goat (Oreamnos americanus) from Kootenay National Park, British Columbia. (This is the first report of CE in mountain goat.) Diagnosis was based on clinical signs, histopathology, transmission experiments and the demonstration of a proxvirus with the electron microscope. The infection was transmitted from wild to domestic goat, but not to domestic sheep. Most infections, some of them severe, were found in lambs and kids. Clinical signs of disease were similar to those seen in domestic sheep and goats. General body condition was poor and animals had difficulty feeding normally. All infected herds had prolonged contact with areas where salt was provided artificially (i.e., salt blocks, highways and campgrounds). Fewer infected sheep were observed annually when salt blocks were removed from Jasper National Park. PMID:1113436

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

1975-01-01

180

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

E-print Network

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

Ackerman, Joshua

181

A Recently Evolved Sublineage of the Mycobacterium tuberculosis Beijing Strain Family Is Associated with an Increased Ability to Spread and Cause Disease  

Microsoft Academic Search

This study aimed to reconstruct the evolutionary history of Beijing strains of Mycobacterium tuberculosis and to test the hypothesis that evolution has influenced the ability of the Beijing strains within the different Beijing sublineages to spread and cause disease. A PCR-based method was used to analyze the genome structure of 40 different loci in 325 Beijing isolates collected from new

M. Hanekom; G. D. van der Spuy; E. Streicher; S. L. Ndabambi; C. R. E. McEvoy; M. Kidd; N. Beyers; T. C. Victor; P. D. van Helden; R. M. Warren

2007-01-01

182

Efficient detection of contagious outbreaks in massive metropolitan encounter networks  

PubMed Central

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

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

2014-01-01

183

Efficient detection of contagious outbreaks in massive metropolitan encounter networks.  

PubMed

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

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

2014-01-01

184

Efficient detection of contagious outbreaks in massive metropolitan encounter networks  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

185

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. PMID:23251507

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

2012-01-01

186

Marek's disease virus and skin interactions.  

PubMed

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

Couteaudier, Mathilde; Denesvre, Caroline

2014-01-01

187

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

Federal Register 2010, 2011, 2012, 2013

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

2011-05-31

188

Challenges of controlling contagious bovine pleuropneumonia in sub-Saharan Africa: a Zambian perspective.  

PubMed

Contagious bovine pleuropneumonia (CBPP) is a disease of economic importance that is widely distributed in sub-Saharan African and contributes significantly to cattle morbidity and mortality. Control of CBPP offers a number of challenges as a result many developing countries in Africa are still struggling with this disease. In this study, we look at the challenges encountered in CBPP control in sub-Saharan Africa from the Zambian perspective. In conducting this study, we reviewed scientific literature and reports from the Ministry of Agriculture and Livestock and related animal institutions, and also made interviews with experts and key government officials involved in CBPP control in Zambia. Among the challenges identified for the successful control of CBPP were as follows: failure in the delivery of veterinary services, lack of a cattle identification system, natural phenomenon, livestock husbandry systems in the traditional sector, human movements, traditional practices among cattle farmers and cattle marketing systems. It was seen that the epidemiology of CBPP in Zambia is influenced by both ecological and anthological factors. Therefore, design and implementation of any control or eradication programme should be area/regional-dependent taking into account the different factors influencing disease transmission and maintenance. PMID:22843213

Muuka, Geoffrey; Songolo, Nadi; Kabilika, Swithine; Hang'ombe, Bernard M; Nalubamba, King S; Muma, John B

2012-12-01

189

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

PubMed

Hand-reared mule deer fawns (Odocoileus hemionus), white-tailed deer fawns (Odocoileus virginianus), pronghorn fawns (Antilocapra americana) and wapiti calves (Cervus elaphus nelsoni) were exposed to contagious ecthyma lesion material obtained from Rocky Mountain bighorn sheep (Ovis canadensis canadensis) to determine the susceptibility and pathogenesis in these species. All four species developed mucocutaneous proliferative lesions of the oral cavity, grossly and histologically compatible with contagious ecthyma. The limited clinical responses to the virus indicated that contagious ecthyma would not seriously impact free-ranging individuals. PMID:6685778

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

1983-07-01

190

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

191

Spill Spread  

NSDL National Science Digital Library

In this simulation, learners explore how ocean currents spread all kinds of pollutionâincluding oil spills, sewage, pesticides and factory wasteâfar beyond where the pollution originates. Learners create an experimental "ocean" (water in a tray) and "continents" (rocks), then add melting ice cubes to create temperature-driven currents in the water. Learners observe how "pollution," represented by food coloring, spreads through the model ocean affected by both "currents" and "continents." This activity can be used with lessons on ocean science or environmental hazards.

Science, Lawrence H.

2007-01-01

192

Children's understanding of the transmission of genetic disorders and contagious illnesses.  

PubMed

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 a contagion context. Studies 3 and 4 presented preschoolers and adults with novel (fictitious) illnesses to determine which cues participants would use to differentiate the modes of transmission. In the presence of kinship cues, children distinguished genetic disorders from contagious illnesses, but in the presence of contagion cues, preschoolers selectively applied contagious links primarily to contagious illnesses. With novel illnesses, preschoolers and adults inferred that permanent illnesses were more likely to be transmitted by birth parents than by contagion. These results suggest that by the preschool years, children recognize that not all disorders are transmitted exclusively through germ contagion. PMID:15656747

Raman, Lakshmi; Gelman, Susan A

2005-01-01

193

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

PubMed

Foot-and-mouth disease (FMD) is a highly contagious and rapidly spreading disease of cloven-hoofed animals. In most countries, animals are immunized with inactivated whole virus vaccines to control the spread of foot-and-mouth disease virus (FMDV); however, there are safety and efficacy (especially, cell-mediated immunity) concerns. Many efforts are currently devoted to the development of effective vaccines by combining the application of protective antigens together with the search for specific and targeting adjuvants that maximizes the immunogenicity with a desired immune response. In this review, we outline previous studies performed with both traditional adjuvants as well as the most promising new generation adjuvants such as ligands for Toll-like receptors (TLRs) or different cytokines, focusing mostly on their efficacy when used with FMD vaccine, and somewhat on mechanisms by which adjuvants mediate their effects. PMID:25234962

Cao, Yimei

2014-11-01

194

Contagious parthenogenesis, automixis, and a sex determination meltdown.  

PubMed

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

Engelstädter, Jan; Sandrock, Christoph; Vorburger, Christoph

2011-02-01

195

Phase diagram of epidemic spreading — unimodal vs. bimodal probability distributions  

NASA Astrophysics Data System (ADS)

Disease spreading on complex networks is studied in SIR model. Simulations on empirical complex networks reveal two specific regimes of disease spreading: local containment and epidemic outbreak. The variables measuring the extent of disease spreading are in general characterized by a bimodal probability distribution. Phase diagrams of disease spreading for empirical complex networks are introduced. A theoretical model of disease spreading on m-ary tree is investigated both analytically and in simulations. It is shown that the model reproduces qualitative features of phase diagrams of disease spreading observed in empirical complex networks. The role of tree-like structure of complex networks in disease spreading is discussed.

Lan?i?, Alen; Antulov-Fantulin, Nino; Šiki?, Mile; Štefan?i?, Hrvoje

2011-01-01

196

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

PubMed Central

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

2013-01-01

197

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

PubMed Central

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

2013-01-01

198

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

Code of Federal Regulations, 2010 CFR

...of disease by artificial insemination of turkeys. 147.27 Section 147.27 Animals...of disease by artificial insemination of turkeys. (a) The vehicle transporting the...should be left as far as practical from the turkey pens. (b) The personnel of...

2010-01-01

199

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

2013-07-01

200

Highly Pathogenic Avian Influenza Virus H7N7 Isolated From a Fatal Human Case Causes Respiratory Disease in Cats but Does Not Spread Systemically  

PubMed Central

Highly pathogenic avian influenza viruses (HPAIV) of the H5 and H7 subtypes primarily infect poultry but are occasionally transmitted to humans and other mammalian species, often causing severe disease. Previously we have shown that HPAIV H5N1 causes severe systemic disease in cats. In this study, we investigated whether HPAIV H7N7 isolated from a fatal human case is also able to cause disease in cats. Additionally, we compared the cell tropism of both viruses by immunohistochemistry and virus histochemistry. Three domestic cats were inoculated intratracheally with HPAIV H7N7. Virus excretion was restricted to the pharynx. At necropsy, 7 days post inoculation, lesions were restricted to the respiratory tract in all cats. Lesions consisted of diffuse alveolar damage and colocalized with virus antigen expression in type II pneumocytes and nonciliated bronchiolar cells. The attachment patterns of HPAIV H7N7 and H5N1 were similar: both viruses attached to nonciliated bronchiolar epithelial cells, type II pneumocytes, as well as alveolar macrophages. These data show for the first time that a non-H5 HPAIV is able to infect and cause respiratory disease in cats. The failure of HPAIV H7N7 to spread beyond the respiratory tract was not explained by differences in cell tropism compared to HPAIV H5N1. These findings suggest that HPAIV H5N1 possesses other characteristics that allow it to cause systemic disease in both humans and cats. PMID:20847292

van Riel, Debby; Rimmelzwaan, Guus F.; van Amerongen, Geert; Osterhaus, Albert D.M.E.; Kuiken, Thijs

2010-01-01

201

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

202

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

PubMed

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

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

2014-04-01

203

Contagious yawning in gelada baboons as a possible expression of empathy  

PubMed Central

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.

2009-01-01

204

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

205

The effect of heterogeneous infectious period and contagiousness on the dynamics of Salmonella transmission in dairy cattle  

Microsoft Academic Search

The objective of this study was to address the impact of heterogeneity of infectious period and contagiousness on Salmonella transmission dynamics in dairy cattle populations. We developed three deterministic SIR-type models with two basic infected stages (clinically and subclinically infected). In addition, model 2 included long-term shedders, which were defined as individuals with low contagiousness but long infectious period, and

Cristina Lanzas; S. BRIEN; R. IVANEK; Y. LO; P. AYSCUE

2008-01-01

206

Poleward expansion of the white-footed mouse (Peromyscus leucopus) under climate change: implications for the spread of lyme disease.  

PubMed

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

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

2013-01-01

207

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

PubMed Central

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

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

2013-01-01

208

A community-wide outbreak of legionnaires disease linked to industrial cooling towers--how far can contaminated aerosols spread?  

PubMed

A community-wide outbreak of legionnaires disease occurred in Pas-de-Calais, France, in November 2003-January 2004. Eighteen (21%) of 86 laboratory-confirmed cases were fatal. A case-control study identified smoking, silicosis, and spending >100 min outdoors daily as risk factors for acquiring the disease. Legionella pneumophila strain Lens was isolated from cooling towers, wastewater, and air samples from plant A. This unique strain matched all 23 clinical isolates, as assessed by pulsed-field gel electrophoresis subtyping. Modeling of atmospheric dispersion of aerosols emitted from plant A cooling towers showed good coverage of the communes where patients lived and showed that the dispersion extended over a distance of at least 6 km from plant A. No other aerosol-producing installation was identified as a plausible source, and no common source of indoor exposure was found. These findings implicate plant A as the most likely outbreak source and suggest that the distance of airborne transmission of L. pneumophila may be greater than previously reported. PMID:16323138

Nguyen, Tran Minh Nhu; Ilef, Daniele; Jarraud, Sophie; Rouil, Laurence; Campese, Christine; Che, Didier; Haeghebaert, Sylvie; Ganiayre, Francois; Marcel, Frederic; Etienne, Jerome; Desenclos, Jean-Claude

2006-01-01

209

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

210

The immunizing dose of T 1 strain Mycoplasma mycoides against contagious bovine pleuropneumonia  

Microsoft Academic Search

Cattle vaccinated against Contagious Bovine Pleuropneumonia with the T1 strain ofMycoplasma mycoides with doses of 109, 107 and 105 colony forming units were challenged six months later by the ‘in contact’ method, namely mixing with vrtificially infected ‘donor’ animals. The results of the experiment suggest that the vaccinating dose of this strain should not contain less than 107 colony forming

F. R. Gilbert; R. S. Windsor

1971-01-01

211

EXPERIMENTAL CONTAGIOUS ECTHYMA IN MULE DEER, WHITE-TAILED DEER, PRONGHORN AND WAPITI1  

Microsoft Academic Search

Hand-reared mule deer fawns (Odocoileus hemionus), white-tailed deer fawns (Odocoileus virginianus), pronghorn fawns (Antilocapra americana) and wapiti calves (Cervus elaphus nelsoni) were exposed to contagious ecthyma lesion material obtained from Rocky Mountain bighorn sheep (Ocis cana- densis canadensis) to determine the susceptibility and pathogenesis in these species. All four species devel- oped mucocutaneous proliferative lesions of the oral cavity, grossly

William R. Lance; Charles P. Hibler; James DeMartini

212

What is the flu? Influenza, "the flu" is a contagious respiratory infection  

E-print Network

What is the flu? Influenza, "the flu" is a contagious respiratory infection caused by the influenza known as "swine flu") in humans causes similar symptoms to the seasonal flu but may also include. What are the symptoms? Flu symptoms start 1-4 days after exposure. Symptoms usually start suddenly

Virginia Tech

213

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

214

Truthful germs are contagious: A local to global characterization of truthfulness  

E-print Network

Truthful germs are contagious: A local to global characterization of truthfulness Aaron Archer AT of outcomes is truthful, i.e. implementable by a truthful mechanism. In particular, if the restriction of f to every "simple" subset of the type space is truthful, does it imply that f is truthful? Saks and Yu

Kleinberg, Robert D.

215

Epitope spreading of the anti-citrullinated protein antibody response occurs before disease onset and is associated with the disease course of early arthritis  

Microsoft Academic Search

BackgroundAnti-citrullinated protein antibodies (ACPA) are the most predictive factor for the development of rheumatoid arthritis (RA).ObjectiveTo investigate whether the recognition of citrullinated epitopes changes during disease onset or progression, by studying the fine specificity of ACPA in serum samples collected throughout the disease course, from before the onset of arthritis to longstanding RA.MethodsAntibodies recognising five distinct citrullinated antigens were determined

Diane van der Woude; Solbritt Rantapää-Dahlqvist; Andreea Ioan-Facsinay; Carla Onnekink; Carla M Schwarte; Kirsten N Verpoort; Jan W Drijfhout; Tom W J Huizinga; Rene E M Toes; Ger J M Pruijn

2010-01-01

216

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

217

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

218

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

219

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

Code of Federal Regulations, 2010 CFR

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

2010-01-01

220

Experimental parapoxvirus infection (contagious ecthyma) in semi-domesticated reindeer (Rangifer tarandus tarandus).  

PubMed

Contagious ecthyma (contagious pustular dermatitis, orf) occurs world-wide in sheep and goats and is caused by orf virus (genus Parapoxvirus, family Poxviridae). Contagious ecthyma outbreaks have been described in semi-domesticated reindeer (Rangifer tarandus tarandus) in Sweden, Finland and Norway, occasionally with high mortality. Fourteen one-year-old reindeer were corralled in mid-April. One week after arrival, two animals received a commercial live orf virus vaccine for sheep (Scabivax(®)) on scarified skin of the medial thigh. Four weeks later, the two vaccinated and six additional animals were inoculated in scarified oral mucosa with parapoxvirus obtained from reindeer with clinical contagious ecthyma. The remaining six reindeer were kept as sentinels, sharing feed and water with the inoculated animals. A small whitish lesion appeared on the inoculation site and the labial skin-mucosa junction of three animals five days post inoculation (p.i.). Twelve days p.i., typical ecthyma lesions were visible on the inoculation site in six of eight animals, including both vaccinees. Four inoculated animals (including both vaccinees) and one sentinel seroconverted 12 days p.i., and five animals (including one sentinel) seroconverted 20 days p.i. No contagious ecthyma-like lesions were detected in the sentinels. All animals were euthanized at 26-29 days p.i. Histological examination of lesions showed proliferative dermatitis with epidermal hyperplasia, hyperkeratosis, intra-epithelial pustules and ulcers. Orf virus DNA was detected in mandibular lymph nodes, tonsils and mucosal lesions of four animals, including one sentinel, which showed that virus transmission took place. The commercial orf virus vaccine may be difficult to administer due to the need for close-cropping and its zoonotic nature, and did not indicate significant protection, although the latter has to be verified with a larger number of animals. PMID:23201244

Tryland, Morten; Klein, Jörn; Berger, Therese; Josefsen, Terje D; das Neves, Carlos G; Oksanen, Antti; Åsbakk, Kjetil

2013-03-23

221

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.

222

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

PubMed

Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides (Mmm) is an economically very important cattle disease in sub-Saharan Africa. CBPP impacts animal health and poverty of livestock-dependent people through decreased animal productivity, reduced food supply, and the cost of control measures. CBPP is a barrier to trade in many African countries and this reduces the value of livestock and the income of many value chain stakeholders. The presence of CBPP also poses a constant threat to CBPP-free countries and creates costs in terms of the measures necessary to ensure the exclusion of disease. This opinion focuses on the biomedical research needed to foster the development of better control measures for CBPP. We suggest that different vaccine development approaches are followed in parallel. Basic immunology studies and systematic OMICs studies will be necessary in order to identify the protective arms of immunity and to shed more light on the pathogenicity mechanisms in CBPP. Moreover a robust challenge model and a close collaboration with African research units will be crucial to foster and implement a new vaccine for the progressive control of this cattle plague. PMID:24359340

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

2013-01-01

223

Governing the contagious body: genital herpes, contagion and technologies of the self.  

PubMed

Genital herpes is a prevalent sexually transmitted viral infection. While genital herpes is not life-threatening, it can cause physical discomfort and psychosocial difficulties, and may increase the risk of contracting HIV. Given that genital herpes cannot be cured, both the condition itself, and the possibility of passing it on to others, becomes a part of the everyday reality of those individuals diagnosed with genital herpes. In this article we explore the ways in which people with genital herpes attending the Sexually Transmitted Infections (STI) clinic govern their 'contagious bodies'. The discussion draws on the Foucauldian concept of governmentality, and uses Foucault's idea of ethics as a framework to identify the technologies of the self by which individuals with genital herpes govern their own thoughts and behaviours in relation to the contagiousness of the condition. Implications for practice and other ways of thinking about what happens in the STI clinic context are suggested. PMID:18400830

Oster, Candice; Cheek, Julianne

2008-04-01

224

Shelf life of wet T 1 broth vaccine for contagious bovine pleuropneumonia  

Microsoft Academic Search

Monthly viable counts and pH monitoring of several batches of wet contagious bovine pleuropneumonia broth vaccine preserved at 4°C were done. The viable counts of all the batches did not drop below 107 cfu\\/ml until after 4 months. The pH of the broth vaccine also stayed at approximately 7.55 for a period of 11 months. The investigation showed that the

Samuel A. Garba

1980-01-01

225

25 CFR 168.15 - Control of livestock diseases and parasites.  

...diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or parasites or have been exposed thereto, such livestock must be treated and the movement thereof restricted in...

2014-04-01

226

25 CFR 168.15 - Control of livestock diseases and parasites.  

Code of Federal Regulations, 2010 CFR

...diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or parasites or have been exposed thereto, such livestock must be treated and the movement thereof restricted in...

2010-04-01

227

25 CFR 168.15 - Control of livestock diseases and parasites.  

Code of Federal Regulations, 2012 CFR

...diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or parasites or have been exposed thereto, such livestock must be treated and the movement thereof restricted in...

2012-04-01

228

25 CFR 168.15 - Control of livestock diseases and parasites.  

Code of Federal Regulations, 2013 CFR

...diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or parasites or have been exposed thereto, such livestock must be treated and the movement thereof restricted in...

2013-04-01

229

25 CFR 168.15 - Control of livestock diseases and parasites.  

Code of Federal Regulations, 2011 CFR

...diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or parasites or have been exposed thereto, such livestock must be treated and the movement thereof restricted in...

2011-04-01

230

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

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Appearance of disease among horses in quarantine. 93.313 Section 93...MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.313 Appearance of disease among horses in quarantine. If any contagious...

2010-01-01

231

Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 2. Description of outbreaks by size, severity, and settings.  

PubMed

This article is the second in a series of several by members of the Committee on the Control of Foodborne Illness of the International Association of Food Protection, and it continues the analysis of 816 outbreaks where food workers were implicated in the spread of foodborne disease. In this article, we discuss case morbidity and mortality and the settings where the 816 outbreaks occurred. Some of the outbreaks were very large; 11 involved more than 1,000 persons, 4 with more than 3,000 ill. The larger outbreaks tended to be extended over several days with a continuing source of infections, such as at festivals, resorts, and community events, or the contaminated product had been shipped to a large number of customers, e.g., icing on cakes or exported raspberries. There were five outbreaks with more than 100 persons hospitalized, with rates ranging from 9.9 to 100%. However, overall, the hospitalization rate was low (1.4%), and deaths were rare (0.11% of the 80,682 cases). Many of the deaths were associated with high-risk persons (i.e., those who had underlying diseases, malnutrition, or both, as in a refugee camp, or young children), but a few occurred with apparently healthy adults. An analysis of the settings for the food worker-related events showed that most of the outbreaks came from food service facilities (376 outbreaks [46.1%]), followed by catered events (126 outbreaks [15.4%]), the home (83 outbreaks [10.2%]), schools and day care centers (49 [6.0%]), and health care institutions (43 outbreaks [5.3%]). However, many cases resulted from relatively few outbreaks (< 30 each) associated with community events (9,726), processing plants (8,580), mobile/temporary service (5,367), and camps/ armed forces (5,117). The single most frequently reported setting was restaurants, with 324 outbreaks and 16,938 cases. Improper hygienic practices in homes, on picnics, or at community events accounted for 89 of the 816 outbreaks. There were 18 outbreaks associated with commercial travel in air flights, trains, and cruise ships over several decades, although only the last seems to be a major concern today. Sixteen outbreaks occurred where food, primarily produce, was harvested and shipped from one country to another. Sometimes the presence of an infected worker preparing food was only one of several factors contributing to the outbreak. PMID:17803160

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

2007-08-01

232

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

233

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

PubMed

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

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

2014-08-01

234

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.

235

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

236

The effect of heterogeneous infectious period and contagiousness on the dynamics of Salmonella transmission in dairy cattle  

PubMed Central

SUMMARY The objective of this study was to address the impact of heterogeneity of infectious period and contagiousness on Salmonella transmission dynamics in dairy cattle populations. We developed three deterministic SIR-type models with two basic infected stages (clinically and subclinically infected). In addition, model 2 included long-term shedders, which were defined as individuals with low contagiousness but long infectious period, and model 3 included super-shedders (individuals with high contagiousness and long infectious period). The simulated dynamics, basic reproduction number (R0) and critical vaccination threshold were studied. Clinically infected individuals were the main force of infection transmission for models 1 and 2. Long-term shedders had a small impact on the transmission of the infection and on the estimated vaccination thresholds. The presence of super-shedders increases R0 and decreases the effectiveness of population-wise strategies to reduce infection, making necessary the application of strategies that target this specific group. PMID:18198002

LANZAS, C.; BRIEN, S.; IVANEK, R.; LO, Y.; CHAPAGAIN, P. P.; RAY, K. A.; AYSCUE, P.; WARNICK, L. D.; GRÖHN, Y. T.

2008-01-01

237

The effect of heterogeneous infectious period and contagiousness on the dynamics of Salmonella transmission in dairy cattle.  

PubMed

The objective of this study was to address the impact of heterogeneity of infectious period and contagiousness on Salmonella transmission dynamics in dairy cattle populations. We developed three deterministic SIR-type models with two basic infected stages (clinically and subclinically infected). In addition, model 2 included long-term shedders, which were defined as individuals with low contagiousness but long infectious period, and model 3 included super-shedders (individuals with high contagiousness and long infectious period). The simulated dynamics, basic reproduction number (R0) and critical vaccination threshold were studied. Clinically infected individuals were the main force of infection transmission for models 1 and 2. Long-term shedders had a small impact on the transmission of the infection and on the estimated vaccination thresholds. The presence of super-shedders increases R0 and decreases the effectiveness of population-wise strategies to reduce infection, making necessary the application of strategies that target this specific group. PMID:18198002

Lanzas, C; Brien, S; Ivanek, R; Lo, Y; Chapagain, P P; Ray, K A; Ayscue, P; Warnick, L D; Gröhn, Y T

2008-11-01

238

2SI2R rumor spreading model in homogeneous networks  

NASA Astrophysics Data System (ADS)

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

Wang, Jiajia; Zhao, Laijun; Huang, Rongbing

2014-11-01

239

Prevalence, risk factors and vaccination efficacy of contagious ovine ecthyma (orf) in England.  

PubMed

Orf is a viral disease found in English sheep flocks which can cause economic losses. It is a zoonosis with little epidemiological research available in the UK. In 2012, 3000 questionnaires were sent to English sheep farms in order to investigate the prevalence of orf, determine vaccination efficacy and to identify some of the potential risk factors. The usable response rate was 25.4 per cent. The usable farms (N=762 in the years 2011 and 2012) were used to model the percentage of animals affected on the farm, and the probability of a farm being found with the disease. The disease prevalence (DP) was standardised for the year and calculated as 1.88 per cent for ewes and 19.53 per cent for lambs. The disease risk ratio (RR) for the use of the vaccine was calculated as 2.04 for ewes and 0.75 for lambs, and therefore, the study found that lamb vaccination was beneficial (RR <1). Weed infestation and an increased number of orphan lambs were associated with increased cases of orf. We conclude that the DP in ewes and lambs affect each other, though the impact is higher for lambs in the presence of increasing prevalence in ewes. A short lambing season lowers the probability of a farm experiencing cases of orf. Vaccination was effective in lambs but not in ewes, though lambs benefitted when ewes were vaccinated (reduced orf prevalence in lambs born from vaccinated ewes), probably because any unvaccinated ewes may have been carriers that could spread the virus to the new-born lambs. PMID:24996900

Onyango, J; Mata, F; McCormick, W; Chapman, S

2014-10-01

240

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

241

Characterization of Anamnestic T-cell Responses Induced by Conventional Vaccines against Contagious Bovine Pleuropneumonia  

PubMed Central

A better understanding of how T1 vaccination confers immunity would facilitate the rational design of improved vaccines against contagious bovine pleuropneumonia (CBPP). We show here that mycoplasmas-induced recall proliferation and IFN-? responses are detected in cattle that received multiple shots of T1 vaccines. These anamnestic responses were under the strict control of CD4+ T lymphocytes. Moreover, CD62L expression indicated that both CD4+ effector memory (Tem) and central memory (Tcm) T lymphocytes are elicited in these animals. Comparative analysis with data from cattle that completely recovered from CBPP infection revealed similar anamnestic T-cell responses albeit at a lower magnitude for T1-vaccinated animals, particularly in the Tcm compartment. In conclusion, we discuss how our current understanding of T-cell responses will contribute to ongoing efforts for the improvement of future CBPP vaccines. PMID:23469008

Totte, Philippe; Yaya, Aboubakar; Sery, Amadou; Wesonga, Hezron; Wade, Abel; Naessens, Jan; Niang, Mamadou; Thiaucourt, Francois

2013-01-01

242

Controlling contagious agalactia in artificial insemination centers for goats and detection of Mycoplasma mycoides subspecies capri in semen  

Microsoft Academic Search

Many goat artificial insemination (AI) centers in Spain have adopted new measures to control contagious agalactia (CA). To avoid the introduction of male goats carrying mycoplasma organisms subclinically in their external ear canal (auricular carriers) in these centers, two ear swabs and a blood sample are obtained from all candidate animals for polymerase chain reaction (PCR), culture (swabs) and serologic

A. Gómez-Martín; J. C. Corrales; J. Amores; A. Sánchez; A. Contreras; A. Paterna; C. De la Fe

243

[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

244

Perspectives on spreading depression  

Microsoft Academic Search

Spreading depression (SD) consists of a transient suppression of all neuronal activity that spreads slowly across regions of gray matter. The paper is divided into three parts. Martins-Ferreira describes 30 years of research on SD in the isolated retina. Much of this work has relied on the prominent intrinsic optical signals that accompany SD in the retina. By inducing SD

Hiss Martins-Ferreira; Maiken Nedergaard; Charles Nicholson

2000-01-01

245

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

Code of Federal Regulations, 2013 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...

2013-04-01

246

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

...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...

2014-04-01

247

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

Code of Federal Regulations, 2012 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...

2012-04-01

248

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

249

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

Code of Federal Regulations, 2010 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...

2010-04-01

250

Flame Spread Across Liquids  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

251

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

PubMed Central

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

2013-01-01

252

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. PMID:21079667

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

2010-01-01

253

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

2010-01-01

254

How Is Mono Spread?  

MedlinePLUS

... this tool to play your goals. Hot Topics Ebola: The Facts How to Make Sense of Health News Anxiety Disorders Relaxation Exercises The Flu Vaccine How Is Mono Spread? KidsHealth > Teens > Q&A > Mononucleosis > How Is Mono ...

255

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.

256

Effect of Bactericides on Population Sizes and Spread of Clavibacter michiganensis subsp. michiganensis on Tomatoes in the Greenhouse and on Disease Development and Crop Yield in the Field.  

PubMed

ABSTRACT Chemical applications, with the exception of mancozeb, reduced population sizes and spread of Clavibacter michiganensis subsp. michiganensis among tomato seedlings in the greenhouse and impacted subsequent plant development and yield in the field. While applications of copper hydroxide, copper hydroxide/mancozeb, copper hydroxide/mancozeb (premixed 12 h before spraying), streptomycin, and streptomycin/copper hydroxide to seedlings in the greenhouse did not differ significantly from the inoculated control, the trend was for these treatments to increase the survival of inoculated transplants in the field in comparison to the inoculated control. In the field, inoculated controls produced yields that were 63% (1995) and 51% (1996) of those produced by uninoculated controls. In both years, with the exception of mancozeb in 1995, all treatments resulted in yields similar to those obtained with the uninoculated control. Plant survival and yield in the field were severely affected when transplants had a pathogen population of >/= x 10(8) CFU/g of tissue. All treatments, with the exception of mancozeb, limited C. michiganensis subsp. michiganensis populations to <5.0 x 10(5). None of the treatments significantly reduced the incidence of fruit spotting compared with that of the inoculated control. PMID:18944570

Hausbeck, M K; Bell, J; Medina-Mora, C; Podolsky, R; Fulbright, D W

2000-01-01

257

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

Microsoft Academic Search

One of the concerns is that there may exist multiple infectious disease transmission routes across households in high-rise residential buildings, one of which is the natural ventilative airflow through open windows between flats, caused by buoyancy effects. This study presents the modeling of this cascade effect using computational fluid dynamics (CFD) technique. It is found that the presence of the

J. L. Niu; N. P. Gao

2010-01-01

258

ISPM, Division of Biostatistics Modelling power-law spread  

E-print Network

ISPM, Division of Biostatistics Modelling power-law spread of infectious diseases Sebastian Meyer 2013 Page 1 #12;ISPM, Division of Biostatistics Epidemic Modelling ­ Prospective surveillance: outbreak-law spread of infectious diseases Page 2 #12;ISPM, Division of Biostatistics Mobility networks determine

Zurich, University of

259

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

PubMed

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

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

2014-08-01

260

Improved diagnosis for nine viral diseases considered as notifiable by the world organization for animal health.  

PubMed

Nine viral diseases included in the World Organization for Animal Health list of notifiable diseases (former list A) were chosen for their contagiousness and high capacity of spreading to improve their diagnosis using new and emerging technologies. All the selected diseases--foot-and-mouth disease, swine vesicular disease, vesicular stomatitis, classical swine fever, African swine fever, bluetongue, African horse sickness, Newcastle disease and highly pathogenic avian influenza--are considered as transboundary diseases, which detection causes the prohibition of livestock exportation, and, thus, it leads to high economical losses. The applied diagnostic techniques can fall into two categories: (i) nucleic-acid detection, including padlock probes, real-time PCR with TaqMan, minor groove binding probes and fluorescence energy transfer reaction probes, isothermal amplification like the Cleavase/Invader assay or the loop-mediated amplification technology and the development of rapid kits for 'mobile' PCR and (ii) antigen-antibody detection systems like simplified and more sensitive ELISA tests. Besides, internal controls have been improved for nucleic acid-detecting methods by using an RNA plant virus--Cowpea Mosaic Virus--to ensure the stability of the RNA used as a positive control in diagnostic real-time RT-PCR assays. The development of these diagnosis techniques has required the joint efforts of a European consortium in which nine diagnostic laboratories and an SME who have collaborated since 2004 within the European Union-funded Lab-on-site project. The results obtained are shown in this paper. PMID:18666965

Rodriguez-Sanchez, B; Sanchez-Vizcaino, J M; Uttenthal, A; Rasmussen, T B; Hakhverdyan, M; King, D P; Ferris, N P; Ebert, K; Reid, S M; Kiss, I; Brocchi, E; Cordioli, P; Hjerner, B; McMenamy, M; McKillen, J; Ahmed, J S; Belak, S

2008-08-01

261

Presence of contagious agalactia causing mycoplasmas in Spanish goat artificial insemination centres.  

PubMed

Male goats admitted to artificial insemination centres come from herds that have shown no clinical symptoms of contagious agalactia (CA) for the last 6 mo. However, prior reports suggest that this control measure may not be completely effective. This study was designed to detect the presence of CA-causing mycoplasmas in 9 Spanish centres, comprising 159 goats (147 males and 12 teaser does) of 8 different breeds. A microbiological study was conducted during 8 mo on 448 samples (318 ear swabs, 119 semen samples and 11 milk samples). In 86 samples (84 swabs, 1 semen sample and 1 milk sample), CA-causative mycoplasmas were detected by PCR or culture, and 52 animals (49 goat males and 3 teaser does) tested positive. Most of these positive animals were auricular carriers (n = 50), mainly of Mycoplasma mycoides subsp. capri (Mmc), although some M. agalactiae (Ma) and, interestingly, M. capricolum subsp. capricolum (Mcc) carriers were also identified. At least 1 animal infected by CA-causing mycoplasmas was detected in 8 of the 9 centres (88.8%) although in most (66.7%) no infected animals or only 1 or 2 positive animals were identified. Our results indicate the presence of CA carriers as asymptomatic animals in reproductive programmes. These findings have already prompted efficient measures to detect and avoid the entry of these carriers in Spanish centres. We recommend similar measures for all centres in areas where CA is endemic. PMID:21220162

Amores, J; Gómez-Martín, A; Corrales, J C; Sánchez, A; Contreras, A; De la Fe, C

2011-04-15

262

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

NASA Astrophysics Data System (ADS)

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

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

1998-04-01

263

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

2008-12-12

264

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

2013-05-31

265

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. PMID:23805213

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

266

Epidemic spread on weighted networks.  

PubMed

The contact structure between hosts shapes disease spread. Most network-based models used in epidemiology tend to ignore heterogeneity in the weighting of contacts between two individuals. However, this assumption is known to be at odds with the data for many networks (e.g. sexual contact networks) and to have a critical influence on epidemics' behavior. One of the reasons why models usually ignore heterogeneity in transmission is that we currently lack tools to analyze weighted networks, such that most studies rely on numerical simulations. Here, we present a novel framework to estimate key epidemiological variables, such as the rate of early epidemic expansion (r0) and the basic reproductive ratio (R0), from joint probability distributions of number of partners (contacts) and number of interaction events through which contacts are weighted. These distributions are much easier to infer than the exact shape of the network, which makes the approach widely applicable. The framework also allows for a derivation of the full time course of epidemic prevalence and contact behaviour, which we validate with numerical simulations on networks. Overall, incorporating more realistic contact networks into epidemiological models can improve our understanding of the emergence and spread of infectious diseases. PMID:24348225

Kamp, Christel; Moslonka-Lefebvre, Mathieu; Alizon, Samuel

2013-01-01

267

Epidemic Spread on Weighted Networks  

PubMed Central

The contact structure between hosts shapes disease spread. Most network-based models used in epidemiology tend to ignore heterogeneity in the weighting of contacts between two individuals. However, this assumption is known to be at odds with the data for many networks (e.g. sexual contact networks) and to have a critical influence on epidemics' behavior. One of the reasons why models usually ignore heterogeneity in transmission is that we currently lack tools to analyze weighted networks, such that most studies rely on numerical simulations. Here, we present a novel framework to estimate key epidemiological variables, such as the rate of early epidemic expansion () and the basic reproductive ratio (), from joint probability distributions of number of partners (contacts) and number of interaction events through which contacts are weighted. These distributions are much easier to infer than the exact shape of the network, which makes the approach widely applicable. The framework also allows for a derivation of the full time course of epidemic prevalence and contact behaviour, which we validate with numerical simulations on networks. Overall, incorporating more realistic contact networks into epidemiological models can improve our understanding of the emergence and spread of infectious diseases. PMID:24348225

Kamp, Christel; Moslonka-Lefebvre, Mathieu; Alizon, Samuel

2013-01-01

268

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

2012-04-26

269

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

270

Spread spectrum image steganography  

Microsoft Academic Search

In this paper, we present a new method of digitalsteganography, entitled spread spectrum image steganography(SSIS). Steganography, which means "covered writing" in Greek,is the science of communicating in a hidden manner. Followinga discussion of steganographic communication theory and reviewof existing techniques, the new method, SSIS, is introduced. Thissystem hides and recovers a message of substantial length withindigital imagery while maintaining the

Lisa M. Marvel; Charles G. Boncelet Jr.; Charles T. Retter

1999-01-01

271

Predicting infection risk of airborne foot-and-mouth disease  

PubMed Central

Foot-and-mouth disease is a highly contagious disease of cloven-hoofed animals, the control and eradication of which is of significant worldwide socio-economic importance. The virus may spread by direct contact between animals or via fomites as well as through airborne transmission, with the latter being the most difficult to control. Here, we consider the risk of infection to flocks or herds from airborne virus emitted from a known infected premises. We show that airborne infection can be predicted quickly and with a good degree of accuracy, provided that the source of virus emission has been determined and reliable geo-referenced herd data are available. A simple model provides a reliable tool for estimating risk from known sources and for prioritizing surveillance and detection efforts. The issue of data information management systems was highlighted as a lesson to be learned from the official inquiry into the UK 2007 foot-and-mouth outbreak: results here suggest that the efficacy of disease control measures could be markedly improved through an accurate livestock database incorporating flock/herd size and location, which would enable tactical as well as strategic modelling. PMID:18757269

Schley, David; Burgin, Laura; Gloster, John

2008-01-01

272

Asymmetrically interacting spreading dynamics on complex layered networks  

E-print Network

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

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

2014-01-01

273

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. PMID:24146848

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

2013-01-01

274

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. PMID:19623265

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

2009-01-01

275

Spread spectrum image steganography.  

PubMed

In this paper, we present a new method of digital steganography, entitled spread spectrum image steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, error-control coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embedded control, and revision tracking. PMID:18267522

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

1999-01-01

276

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

PubMed Central

The discrepancy between an individual’s loneliness and the number of connections in a social network is well documented, yet little is known about the placement of loneliness within, or the spread of loneliness through, social networks. We use network linkage data from the population-based Framingham Heart Study to trace the topography of loneliness in people’s social networks and the path through which loneliness spreads through these networks. Results indicated that loneliness occurs in clusters, extends up to three degrees of separation, is disproportionately represented at the periphery of social networks, and spreads through a contagious process. The spread of loneliness was found to be stronger than the spread of perceived social connections, stronger for friends than family members, and stronger for women than for men. The results advance our understanding of the broad social forces that drive loneliness and suggest that efforts to reduce loneliness in our society may benefit by aggressively targeting the people in the periphery to help repair their social networks and to create a protective barrier against loneliness that can keep the whole network from unraveling. PMID:19968414

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

2009-01-01

277

Alone in the crowd: the structure and spread of loneliness in a large social network.  

PubMed

The discrepancy between an individual's loneliness and the number of connections in a social network is well documented, yet little is known about the placement of loneliness within, or the spread of loneliness through, social networks. The authors use network linkage data from the population-based Framingham Heart Study to trace the topography of loneliness in people's social networks and the path through which loneliness spreads through these networks. Results indicated that loneliness occurs in clusters, extends up to 3 degrees of separation, is disproportionately represented at the periphery of social networks, and spreads through a contagious process. The spread of loneliness was found to be stronger than the spread of perceived social connections, stronger for friends than family members, and stronger for women than for men. The results advance understanding of the broad social forces that drive loneliness and suggest that efforts to reduce loneliness in society may benefit by aggressively targeting the people in the periphery to help repair their social networks and to create a protective barrier against loneliness that can keep the whole network from unraveling. PMID:19968414

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

2009-12-01

278

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 . PMID:22984642

Novossiolova, Tatyana; Minehata, Masamichi; Dando, Malcolm

2012-01-01

279

About Sexually Transmitted Diseases (STDs)  

MedlinePLUS

KidsHealth > Teens > Sexual Health > STDs & Other Infections > About Sexually Transmitted Diseases (STDs) Print A A A Text Size What's ... STDs Spread Preventing and Treating STDs More Information Sexually transmitted diseases (STDs) are infectious diseases that spread from person ...

280

PREDICTING ROOT SPREAD FROM TRUNK DIAMETER AND BRANCH SPREAD  

Microsoft Academic Search

Trunk diameter and branch crown spread were linearly correlated with root spread in honey locust (Gleditsia triancamhos var. inermis), green ash (Fraxinus pennsylvanica), poplar (Populus X generosa), red maple (Acer rubrum) and southern magnolia (Magnolia grandiflora) but not in live oak (Quercus virginiana). Maximum root spread (excluding live oak) ranged from 1.68 times the dripline forash to 3.77 for magnolia.

Edward F. Gilman

1989-01-01

281

Impact of travel on international spread of antimicrobial resistance  

Microsoft Academic Search

Antimicrobial resistance, an escalating problem worldwide, affects a broad range of human diseases. Excessive and inappropriate drug usage is the key driver for the emergence of resistant organisms. Travel, trade and mass migration form an important mode for their spread. The use of molecular biology provides the means of understanding the genesis and spread of the genes for drug resistance.

Ziad A Memish; S Venkatesh; Atef M Shibl

2003-01-01

282

Fifth disease  

MedlinePLUS

... human parvovirus B19. It often affects preschoolers or school-age children during the spring. The disease spreads through the ... sickle cell anemia Fifth disease can cause severe anemia , which will need medical treatment.

283

Prevent the Spread of Norovirus  

MedlinePLUS

... Submit Button CDC Features Prevent the Spread of Norovirus Language: English Español (Spanish) Share Compartir Norovirus spreads ... cramping, nausea, vomiting, and diarrhea. Anyone Can Get Norovirus Anyone can be infected with noroviruses and get ...

284

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.

285

Epidemic spreading in time-varying community networks  

NASA Astrophysics Data System (ADS)

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

Ren, Guangming; Wang, Xingyuan

2014-06-01

286

Spatial spread of farm animal diseases  

E-print Network

network model with the key structural features of the CTS contact network was constructed, by considering a range of measures of network structure, and testing resulting model networks against CTS-derived networks. The resulting model was shown to predict...

Vernon, Matthew Christopher

287

Prevent the Spread of Zoonotic Diseases (Spanish)  

E-print Network

Tome precauciones al manejar o cuidar de los animales Al dar cuidado rutinario a los animales observe las siguientes precauciones para evitar la transmisi?n de g?rmenes que causan enfermedad. Use ropa y equipo de protecci?n personal La ropa, las... botas y el equipo de protecci?n personal pueden reducir el riesgo de transmitir enfermedades contagiosas a otros animales o personas. Use botas y un conjunto de ropa protectora que usa ?nicamente ? cuando maneja o cuida de los animales. Ejemplos...

Pena, Josefa

2008-11-10

288

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

289

25 CFR 700.723 - Control of livestock disease and parasites.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

290

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

PubMed

Foot-and-mouth disease (FMD) is a highly contagious, debilitating, and globally significant viral disease typically affecting cloven-hoofed hosts. The diagnosis of FMD in bears in Vietnam is described. The current study describes a confirmed case of FMD in a bear species, and the clinical signs compatible with FMD in a Malayan sun bear. Thirteen Asiatic black bears (Ursus thibetanus) and 1 Malayan sun bear (Helarctos malayanus) were apparently affected. In August 2011, an adult bear became lethargic, and developed footpad vesicles. Over 15 days, 14 out of 17 bears developed similar signs; the remaining 3 co-housed bears and another 57 resident bears did not. All affected bears developed vesicles on all footpads, and most were lethargic for 24-48 hr. Nasal and oral lesions were noted in 6 and 3 cases, respectively. Within 1 month, all looked normal. Foot-and-mouth disease virus (FMDV) was detected by reverse transcription polymerase chain reaction, classified as serotype O, and isolated by virus isolation techniques. Phylogenetic analysis demonstrated clustering of 3 bear isolates, in a branch distinct from other FMDV type O isolates. The outbreak likely occurred due to indirect contact with livestock, and was facilitated by the high density of captive bears. It showed that Asiatic black bears are capable of contracting FMDV and developing clinical disease, and that the virus spreads easily between bears in close contact. PMID:25135011

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

2014-09-01

291

Foot-and-mouth disease: susceptibility of domestic poultry and free-living birds to infection and to disease--a review of the historical and current literature concerning the role of birds in spread of foot-and-mouth disease viruses.  

PubMed

Ruminants and pigs are the dominant natural hosts of food-and-mouth disease (FMD) viruses. Approximately 70 additional mammalian species are found to be susceptible under natural or experimental conditions. Reptilia, amphibia, and fish are probably naturally resistant to infection. According to the reviewed literature, domestic birds (chickens, turkeys, guinea fowl, ducks and geese) have been experimentally infected with some strains of FMD viruses and may develop lesions suggestive of FMD such as vesicular lesions on the comb, wattles, eye lids, and feet. Since chickens are to some extent coprophagous, chickens get infected by ingestion of virus under conditions of natural exposure or their plumage gets contaminated in an infectious environment. Thus, domestic birds kept in free-run systems may serve as virus vectors for short distances. Free-living birds, especially starlings (Sturnus vulgaris), sea gulls (Larus canus), house-sparrows (Passer domesticus) have been successfully experimentally infected and developed vesicular lesions on the skin and mucosal membranes of the mouth. During epizootics of FMD the plumage of these free-living birds can be contaminated with FMD viruses and the virus is spread over long distances during migration periods in spring and autumn. Thus migrating birds may assume an active role in long distance dissemination of FMD viruses. PMID:12395578

Kaleta, E F

2002-09-01

292

Differentially expressed genes in Bordetella pertussis strains belonging to a lineage which recently spread globally.  

PubMed

Pertussis is a highly contagious, acute respiratory disease in humans caused by the Gram-negative pathogen Bordetella pertussis. Pertussis has resurged in the face of intensive vaccination and this has coincided with the emergence of strains carrying a particular allele for the pertussis toxin promoter, ptxP3, which is associated with higher levels of pertussis toxin (Ptx) production. Within 10 to 20 years, ptxP3 strains have nearly completely replaced the previously dominant ptxP1 strains resulting in a worldwide selective sweep. In order to identify B. pertussis genes associated with the selective sweep, we compared the expression of genes in ptxP1 and ptxP3 strains that are under control of the Bordetella master virulence regulatory locus (bvgASR). The BvgAS proteins comprise a two component sensory transduction system which is regulated by temperature, nicotinic acid and sulfate. By increasing the sulfate concentration, it is possible to change the phase of B. pertussis from virulent to avirulent. Until recently, the only distinctive phenotype of ptxP3 strains was a higher Ptx production. Here we identify additional phenotypic differences between ptxP1 and ptxP3 strains which may have contributed to its global spread by comparing global transcriptional responses under sulfate-modulating conditions. We show that ptxP3 strains are less sensitive to sulfate-mediated gene suppression, resulting in an increased production of the vaccine antigens pertactin (Prn) and Ptx and a number of other virulence genes, including a type III secretion toxin, Vag8, a protein involved in complement resistance, and lpxE involved in lipid A modification. Furthermore, enhanced expression of the vaccine antigens Ptx and Prn by ptxP3 strains was confirmed at the protein level. Identification of genes differentially expressed between ptxP1 and ptxP3 strains may elucidate how B. pertussis has adapted to vaccination and allow the improvement of pertussis vaccines by identifying novel vaccine candidates. PMID:24416242

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

2014-01-01

293

Tumor-activated protein promotes cancer spread  

Cancer.gov

Researchers at the University of California, San Diego School of Medicine and UC San Diego Moores Cancer Center report that cancers physically alter cells in the lymphatic system – a network of vessels that transports and stores immune cells throughout the body – to promote the spread of disease, a process called metastasis. The findings are published in this week’s online Early Edition of the Proceedings of the National Academy of Sciences.

294

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

295

Lyme Disease Transmission  

MedlinePLUS

... Veterinarians Tool kit Lyme disease quiz Lyme disease transmission The Lyme disease bacterium, Borrelia burgdorferi , is spread ... treatment. There are no reports of Lyme disease transmission from breast milk. Although no cases of Lyme ...

296

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. PMID:11309683

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

297

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

G197del is the most prevalent LDL receptor (LDLR) mutation causing familial hypercholesterolemia (FH) in Ashkenazi Jew (AJ) individuals. The purpose of this study was to determine the origin, age, and population distribution of G197del, as well as to explore environmental and genetic effects on disease expression. Index cases from Israel (n=46), South Africa (n=24), Russia (n=7), The Netherlands (n=1), and the United States (n=1) were enlisted. All trace their ancestry to Lithuania. A highly conserved haplotype (D19S221:104-D19S865:208-D19S413:74) was identified in G197del chromosomes, suggesting the occurrence of a common founder. When two methods were used for analysis of linkage disequilibrium (LD) between flanking polymorphic markers and the disease locus and for the study of the decay of LD over time, the estimated age of the deletion was found to be 20 +/- 7 generations (the 95% confidence interval is 15-26 generations), so that the most recent common ancestor of the mutation-bearing chromosomes would date to the 14th century. This corresponds with the founding of the Jewish community of Lithuania (1338 a.d.), as well as with the great demographic expansion of AJ individuals in eastern Europe, which followed this settlement. The penetrance of mutation-linked severe hypercholesterolemia is high (94% of heterozygotes have a baseline concentration of LDL cholesterol (LDL-C) that is >160 mg/dl), and no significant differences in the mean baseline lipid level of G197del carriers from different countries were found. Polymorphisms of apolipoprotein E and of scavenger-receptor class B type I were observed to have minor effects on the plasma lipid profile. With respect to determinative genetic influences on the biochemical phenotype, there is no evidence that could support the possibility of a selective evolutionary metabolic advantage. Therefore, the founder effect in a rapidly expanding population from a limited number of families remains a simple, parsimonious hypothesis explaining the spread of G197del-LDLR-linked FH in AJ individuals. PMID:11309683

Durst, R; Colombo, R; Shpitzen, S; Avi, L B; Friedlander, Y; Wexler, R; Raal, F J; Marais, D A; Defesche, J C; Mandelshtam, M Y; Kotze, M J; Leitersdorf, E; Meiner, V

2001-05-01

298

Contagious comedies. Addictive reality shows. Controversial documentaries. Unmissable soaps. There's nothing like telly to get students talking on the internet and on campus.  

E-print Network

Contagious comedies. Addictive reality shows. Controversial documentaries. Unmissable soaps. There, social networking sites and blogs, we know that for students the laptop is the new TV. Indeed, 99 live TV, they won't be covered by their parents' TV Licence or their hall's licence. They need

Birmingham, University of

299

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. PMID:22747834

Otto, Michael

2012-01-01

300

Did vaccination slow the spread of bluetongue in France?  

PubMed

Vaccination is one of the most efficient ways to control the spread of infectious diseases. Simulations are now widely used to assess how vaccination can limit disease spread as well as mitigate morbidity or mortality in susceptible populations. However, field studies investigating how much vaccines decrease the velocity of epizootic wave-fronts during outbreaks are rare. This study aimed at investigating the effect of vaccination on the propagation of bluetongue, a vector-borne disease of ruminants. We used data from the 2008 bluetongue virus serotype 1 (BTV-1) epizootic of southwest France. As the virus was newly introduced in this area, natural immunity of livestock was absent. This allowed determination of the role of vaccination in changing the velocity of bluetongue spread while accounting for environmental factors that possibly influenced it. The average estimated velocity across the country despite restriction on animal movements was 5.4 km/day, which is very similar to the velocity of spread of the bluetongue virus serotype 8 epizootic in France also estimated in a context of restrictions on animal movements. Vaccination significantly reduced the propagation velocity of BTV-1. In comparison to municipalities with no vaccine coverage, the velocity of BTV-1 spread decreased by 1.7 km/day in municipalities with immunized animals. For the first time, the effect of vaccination has been quantified using data from a real epizootic whilst accounting for environmental factors known to modify the velocity of bluetongue spread. Our findings emphasize the importance of vaccination in limiting disease spread across natural landscape. Finally, environmental factors, specifically those related to vector abundance and activity, were found to be good predictors of the velocity of BTV-1 spread, indicating that these variables need to be adequately accounted for when evaluating the role of vaccination on bluetongue spread. PMID:24465562

Pioz, Maryline; Guis, Hélène; Pleydell, David; Gay, Emilie; Calavas, Didier; Durand, Benoît; Ducrot, Christian; Lancelot, Renaud

2014-01-01

301

Did Vaccination Slow the Spread of Bluetongue in France?  

PubMed Central

Vaccination is one of the most efficient ways to control the spread of infectious diseases. Simulations are now widely used to assess how vaccination can limit disease spread as well as mitigate morbidity or mortality in susceptible populations. However, field studies investigating how much vaccines decrease the velocity of epizootic wave-fronts during outbreaks are rare. This study aimed at investigating the effect of vaccination on the propagation of bluetongue, a vector-borne disease of ruminants. We used data from the 2008 bluetongue virus serotype 1 (BTV-1) epizootic of southwest France. As the virus was newly introduced in this area, natural immunity of livestock was absent. This allowed determination of the role of vaccination in changing the velocity of bluetongue spread while accounting for environmental factors that possibly influenced it. The average estimated velocity across the country despite restriction on animal movements was 5.4 km/day, which is very similar to the velocity of spread of the bluetongue virus serotype 8 epizootic in France also estimated in a context of restrictions on animal movements. Vaccination significantly reduced the propagation velocity of BTV-1. In comparison to municipalities with no vaccine coverage, the velocity of BTV-1 spread decreased by 1.7 km/day in municipalities with immunized animals. For the first time, the effect of vaccination has been quantified using data from a real epizootic whilst accounting for environmental factors known to modify the velocity of bluetongue spread. Our findings emphasize the importance of vaccination in limiting disease spread across natural landscape. Finally, environmental factors, specifically those related to vector abundance and activity, were found to be good predictors of the velocity of BTV-1 spread, indicating that these variables need to be adequately accounted for when evaluating the role of vaccination on bluetongue spread. PMID:24465562

Pioz, Maryline; Guis, Helene; Pleydell, David; Gay, Emilie; Calavas, Didier; Durand, Benoit; Ducrot, Christian; Lancelot, Renaud

2014-01-01

302

Bayesian Biosurveillance of Disease Outbreaks Gregory F. Cooper  

E-print Network

Bayesian networks to model spatio-temporal patterns of a non-contagious disease (respiratory anthrax) or bioterrorist- induced (e.g., anthrax and smallpox), is a critically important problem today. We need to detect outbreaks as early as possible in order to provide the best response and treatment, as well as improve

Wong, Weng-Keen

303

Prions: generation and spread versus neurotoxicity.  

PubMed

Neurodegenerative diseases are characterized by the aggregation of misfolded proteins in the brain. Among these disorders are the prion diseases, which are transmissible, and in which the misfolded proteins ("prions") are also the infectious agent. Increasingly, it appears that misfolded proteins in Alzheimer and Parkinson diseases and the tauopathies also propagate in a "prion-like" manner. However, the association between prion formation, spread, and neurotoxicity is not clear. Recently, we showed that in prion disease, protein misfolding leads to neurodegeneration through dysregulation of generic proteostatic mechanisms, specifically, the unfolded protein response. Genetic and pharmacological manipulation of the unfolded protein response was neuroprotective despite continuing prion replication, hence dissociating this from neurotoxicity. The data have clear implications for treatment across the spectrum of these disorders, targeting pathogenic processes downstream of protein misfolding. PMID:24860100

Halliday, Mark; Radford, Helois; Mallucci, Giovanna R

2014-07-18

304

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

305

Modeling and simulating a disease outbreak by learning a contagion parameter-based model  

Microsoft Academic Search

Various advanced disease-surveillance models have been developed to provide early detection of infectious disease outbreaks and bioterrorist attacks. New methods that increase the overall detection capabilities of these systems can have a broad practical impact. This paper considers the problem of learning the Contagion Parameter (CP) in a black box model involving healthy, sick and contagious individuals. We base our

B. John Oommen; Dragos Calitoiu

2008-01-01

306

Effects of an animal disease shock on meat markets and producer income  

Microsoft Academic Search

This paper simulates pig producer and slaughterhouse income losses due to a classical swine fever outbreak in Finland. The analysis explicitly takes into account that an outbreak of a highly contagious animal disease can shrink export demand for pig meat. After having observed the disease and its impact on pig meat price, producers can optimize animal stocks thought insemination decisions,

Jarkko K. Niemi; Heikki Lehtonen; Kyösti Pietola

2006-01-01

307

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

308

A spread spectrum network analyser  

Microsoft Academic Search

The paper describes the realisation of a spread spectrum network analyser using appropriate software to control a PC interface card, like a soundcard. The software generates a digitised time waveform consisting of a spread spectrum signal containing a number of equal amplitude spectral components. The interface card converts this waveform to an analogue signal, which is then passed through the

C. J. Kikkert

1999-01-01

309

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

310

Lattice Model for Influenza Spreading with Spontaneous Behavioral Changes  

PubMed Central

Individual behavioral response to the spreading of an epidemic plays a crucial role in the progression of the epidemic itself. The risk perception induces individuals to adopt a protective behavior, as for instance reducing their social contacts, adopting more restrictive hygienic measures or undergoing prophylaxis procedures. In this paper, starting with a previously developed lattice-gas SIR model, we construct a coupled behavior-disease model for influenza spreading with spontaneous behavioral changes. The focus is on self-initiated behavioral changes that alter the susceptibility to the disease, without altering the contact patterns among individuals. Three different mechanisms of awareness spreading are analyzed: the local spreading due to the presence in the neighborhood of infective individuals; the global spreading due to the news published by the mass media and to educational campaigns implemented at institutional level; the local spreading occurring through the “thought contagion” among aware and unaware individuals. The peculiarity of the present approach is that the awareness spreading model is calibrated on available data on awareness and concern of the population about the risk of contagion. In particular, the model is validated against the A(H1N1) epidemic outbreak in Italy during the season, by making use of the awareness data gathered by the behavioral risk factor surveillance system (PASSI). We find that, increasing the accordance between the simulated awareness spreading and the PASSI data on risk perception, the agreement between simulated and experimental epidemiological data improves as well. Furthermore, we show that, within our model, the primary mechanism to reproduce a realistic evolution of the awareness during an epidemic, is the one due to globally available information. This result highlights how crucial is the role of mass media and educational campaigns in influencing the epidemic spreading of infectious diseases. PMID:24376727

Fierro, Annalisa; Liccardo, Antonella

2013-01-01

311

Lattice model for influenza spreading with spontaneous behavioral changes.  

PubMed

Individual behavioral response to the spreading of an epidemic plays a crucial role in the progression of the epidemic itself. The risk perception induces individuals to adopt a protective behavior, as for instance reducing their social contacts, adopting more restrictive hygienic measures or undergoing prophylaxis procedures. In this paper, starting with a previously developed lattice-gas SIR model, we construct a coupled behavior-disease model for influenza spreading with spontaneous behavioral changes. The focus is on self-initiated behavioral changes that alter the susceptibility to the disease, without altering the contact patterns among individuals. Three different mechanisms of awareness spreading are analyzed: the local spreading due to the presence in the neighborhood of infective individuals; the global spreading due to the news published by the mass media and to educational campaigns implemented at institutional level; the local spreading occurring through the "thought contagion" among aware and unaware individuals. The peculiarity of the present approach is that the awareness spreading model is calibrated on available data on awareness and concern of the population about the risk of contagion. In particular, the model is validated against the A(H1N1) epidemic outbreak in Italy during the 2009/2010 season, by making use of the awareness data gathered by the behavioral risk factor surveillance system (PASSI). We find that, increasing the accordance between the simulated awareness spreading and the PASSI data on risk perception, the agreement between simulated and experimental epidemiological data improves as well. Furthermore, we show that, within our model, the primary mechanism to reproduce a realistic evolution of the awareness during an epidemic, is the one due to globally available information. This result highlights how crucial is the role of mass media and educational campaigns in influencing the epidemic spreading of infectious diseases. PMID:24376727

Fierro, Annalisa; Liccardo, Antonella

2013-01-01

312

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. PMID:22776779

2012-01-01

313

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

PubMed Central

We build an agent-based model of incarceration based on the susceptible–infected–suspectible (SIS) model of infectious disease propagation. Our central hypothesis is that the observed racial disparities in incarceration rates between Black and White Americans can be explained as the result of differential sentencing between the two demographic groups. We demonstrate that if incarceration can be spread through a social influence network, then even relatively small differences in sentencing can result in large disparities in incarceration rates. Controlling for effects of transmissibility, susceptibility and influence network structure, our model reproduces the observed large disparities in incarceration rates given the differences in sentence lengths for White and Black drug offenders in the USA without extensive parameter tuning. We further establish the suitability of the SIS model as applied to incarceration by demonstrating that the observed structural patterns of recidivism are an emergent property of the model. In fact, our model shows a remarkably close correspondence with California incarceration data. This work advances efforts to combine the theories and methods of epidemiology and criminology. PMID:24966237

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

2014-01-01

314

Tickborne Diseases  

MedlinePLUS

... the early 1970s, has since spread to every state except Hawaii. One of the newest tickborne diseases to be identified in the United States is called Southern tick-associated rash illness (STARI). ...

315

Review article Molecular characterization, spread  

E-print Network

Review article Molecular characterization, spread and evolution of multidrug resistance developments in the characterization of S. enterica Typhimurium DT104, its chromosomal antibiotic resistance (Received 23 November 2000; accepted 6 February 2001) Abstract ­ Multidrug-resistant Salmonella enterica

Boyer, Edmond

316

Pelvic Inflammatory Disease  

MedlinePLUS

... is not treated promptly. What causes PID? Two sexually transmitted diseases (STDs) — gonorrhea and chlamydia —are the main cause ... A manual examination of a woman’s reproductive organs. Sexually Transmitted Diseases (STDs): Diseases that are spread by sexual contact. ...

317

Modeling the impact of random screening and contact tracing in reducing the spread of HIV q  

E-print Network

predict the effectiveness of control measures on the spread of HIV and other sexually transmitted diseases mechanisms of the disease can help the medical/scientific community understand and anticipate the spread with random screening and contact tracing based on the differential infectivity (DI) model and the staged

Hyman, James "Mac"

318

Avian paramyxovirus type 1 infection of racing pigeons: 5. Continued spread in 1984  

Microsoft Academic Search

The neurotropic disease of pigeons caused by a variant avian paramyxovirus type 1 virus was confirmed in 866 lofts in Great Britain during 1984, in comparison with 192 lofts during July to December 1983. The 1984 outbreaks were spread over 48 counties in England and Wales and three regions in Scotland. The main methods of spread of disease in the

DJ Alexander; SA Lister; GW Wilson

1986-01-01

319

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

320

Comparison of complement fixation test, competitive ELISA and LppQ ELISA with post-mortem findings in the diagnosis of contagious bovine pleuropneumonia (CBPP)  

Microsoft Academic Search

The complement fixation test (CFT), the c-ELISA and an indirect LppQ ELISA were compared to post-mortem (PM) inspection for\\u000a the diagnosis of contagious bovine pleuropneumonia (CBPP). Sera from 797 cattle in the CBPP affected area of Kazungula, Zambia\\u000a and 202 sera from Lusaka, Zambia, a CBPP-free area were used. The clinical history of CBPP was recorded and all the cattle

Geofrey Muuka; Bernard Mudenda Hang’ombe; King Shimumbo Nalubamba; Swithine Kabilika; Lucas Mwambazi; John Bwalya Muma

2011-01-01

321

Tan F. Wong: Spread Spectrum & CDMA 4. Diversity in Spread Spectrum Diversity Reception in Spread Spectrum  

E-print Network

in free space, the loss in power, known as path loss, is given by � ´ µ¾ (4.1) 4.1 #12;Tan F. Wong: Spread channel: Path Loss which describes the loss in power as the radio signal propagates in space Shadowing is on fading and how spread spectrum techniques can help to combat fading in wireless channels. 4.1 Path loss

Wong, Tan F.

322

Competing spreading processes on multiplex networks: awareness and epidemics  

E-print Network

Epidemic-like spreading processes on top of multilayered interconnected complex networks reveal a rich phase diagram of intertwined competition effects. A recent study by the authors [Granell et al. Phys. Rev. Lett. 111, 128701 (2013)] presented the analysis of the interrelation between two processes accounting for the spreading of an epidemics, and the spreading of information awareness to prevent its infection, on top of multiplex networks. The results in the case in which awareness implies total immunization to the disease, revealed the existence of a metacritical point at which the critical onset of the epidemics starts depending on the reaching of the awareness process. Here we present a full analysis of these critical properties in the more general scenario where the awareness spreading does not imply total immunization, and where infection does not imply immediate awareness of it. We find the critical relation between both competing processes for a wide spectrum of parameters representing the interacti...

Granell, Clara; Arenas, Alex

2014-01-01

323

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

PubMed

CBPP is an important transboundary disease in sub-Saharan Africa whose control is urgent. Participatory data collection involving 52 focus group discussions in 37 village clusters and key informant interviews, a cross-sectional study involving 232 households and a post-vaccination follow up involving 203 households was carried out in 2006-2007 in Narok South district of Kenya. This was to investigate knowledge, attitudes, perceptions and practices (KAPP) associated with control of CBPP as well as the adverse post-vaccination reactions in animals in order to advice the control policy. The community perceived trans-boundary CBPP threat to their cattle. They had traditional disease coping mechanisms and were conversant with CBPP prevention and control with 49.8% (95%CI: 42.8-56.7%) giving priority to CBPP control. However, 12.9% (95%CI: 9.0-18.1%) of pastoralists had no knowledge of any prevention method and 10.0% (95%CI: 6.5-14.7%) would not know what to do or would do nothing in the event of an outbreak. Although 43.5% (95%CI: 37.1-50.2%) of pastoralists were treating CBPP cases with antimicrobials, 62.5% (95%CI: 52.1-71.7%) of them doubted the effectiveness of the treatments. Pastoralists perceived vaccination to be the solution to CBPP but vaccination was irregular due to unavailability of the vaccine. Vaccination was mainly to control outbreaks rather than preventive and exhibited adverse post-vaccination reactions among 70.4% (95%CI: 63.6-76.5%) of herds and 3.8% (95%CI: 3.5-4.2%) of animals. Consequently, nearly 25.2% (95%CI: 18.5-33.2%) of pastoralists may resist subsequent vaccinations against CBPP. Pastoralists preferred CBPP vaccination at certain times of the year and that it is combined with other vaccinations. In conclusion, pastoralists were not fully aware of the preventive measures and interventions and post-vaccination reactions may discourage subsequent CBPP vaccinations. Consequently there is need for monitoring and management of post vaccination reactions and awareness creation on CBPP prevention and interventions and their merits and demerits. CBPP vaccine was largely unavailable to the pastoralists and the preference of the pastoralists was for vaccination at specified times and vaccine combinations which makes it necessary to avail the vaccine in conformity with the pastoralists preferences. In addition, planning vaccinations should involve pastoralists and neighbouring countries. As the results cannot be generalized, further studies on CBPP control methods and their effectiveness are recommended. PMID:24768437

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

2014-08-01

324

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. PMID:23675416

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

2013-01-01

325

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

PubMed Central

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

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

2013-01-01

326

Using a Bear Put Spread  

E-print Network

at a lower strike price. Typically, both options are traded in the same contract month. The spread loss is limited to the difference between the cost of the put option bought and the put option sold, plus commissions (i.e., the net cost Stan Bevers... at a lower strike price. Typically, both options are traded in the same contract month. The spread loss is limited to the difference between the cost of the put option bought and the put option sold, plus commissions (i.e., the net cost Stan Bevers...

Bevers, Stan; Amosson, Stephen H.; Waller, Mark L.; Dhuyvetter, Kevin C.

2008-10-07

327

Braze alloy spreading on steel  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

328

Activation of the immune response against Infectious Bursal Disease Virus after intramuscular inoculation of an intermediate strain.  

PubMed

Infectious bursal disesase is a highly contagious, wide spread immunosuppressive chicken disease caused by the Infectious Bursal Disease Virus (IBDV). IBDV is a two segmented double-strand RNA virus, member of the Birnaviridae family. In order to study the interaction between IBDV and the immune system, chickens were exposed to an intermediate IBDV strain by intramuscular route, and using Real Time PCR the expression of a panel of avian cytokines and chemokines in duodenum, spleen and bursa of Fabricius was analyzed. Also, splenic nitrite (NO?) production and the frequencies of different mononuclear cell populations were evaluated by Griess reaction and flow cytometry, respectively. Intramuscular (i.m.) IBDV inoculation promoted an over expression of proinflammatory cytokines IL-6, IL-15 and gIFN in spleen, which correlated with an increase of gIFN plasma concentration measured by ELISA, together with an increment of NO? concentration in splenocyte supernatants at 1dpi. Results obtained in the present work showed that IBDV of intermediate virulence, given i.m., induced similar effects to those previously described for highly virulent IBDV in early innate immune responses. Considering that the i.m. route is the route of choice for the delivery of new generation vaccines, and that the use of recombinant antigens also requires the addition of adjuvants for proper immune stimulation, results presented here could contribute to identify suitable cytokines to be used or to be stimulated when utilizing subunit vaccines, for the improvement of prevention tools for avian health. PMID:21514000

Carballeda, Juan Manuel; Zoth, Silvina Chimeno; Gómez, Evangelina; Gravisaco, María José; Berinstein, Analía

2011-09-01

329

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

PubMed Central

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

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

2014-01-01

330

Controlling contagious agalactia in artificial insemination centers for goats and detection of Mycoplasma mycoides subspecies capri in semen.  

PubMed

Many goat artificial insemination (AI) centers in Spain have adopted new measures to control contagious agalactia (CA). To avoid the introduction of male goats carrying mycoplasma organisms subclinically in their external ear canal (auricular carriers) in these centers, two ear swabs and a blood sample are obtained from all candidate animals for polymerase chain reaction (PCR), culture (swabs) and serologic tests to detect the presence of mycoplasmas. In addition, the semen produced at these centers is routinely cultured and PCR tested also to detect the presence of mycoplasmas. One y after the introduction of this program, we tested 48 ear swabs and 24 blood samples from 24 candidates for admission to these AI Centers. Three of these ear swab samples (3/48, 6.25%) scored positive for the presence of mycoplasmas; Mycoplasma agalactiae (Ma) was detected in two samples and Mycoplasma mycoides subsp. capri (Mmc) in one. All animals were serologically negative for Ma. Also, out of 173 semen samples obtained from 137 admitted animals (2 and 3 samples were obtained in 16 and 10 bucks, respectively), one (1/173, 0.56%) was positive for Mmc. Our findings suggest that ear swab and semen samples are useful tools to control CA at AI Centers. The introduction of this program has also resulted in the first detection of Mmc in semen from a naturally infected goat, confirming the ability of this mycoplasma to colonize the reproductive tract of male goats. These results highlight the need to improve control measures in semen producing centers to minimize the risk of CA transmission. PMID:22115814

Gómez-Martín, A; Corrales, J C; Amores, J; Sánchez, A; Contreras, A; Paterna, A; De la Fe, C

2012-04-01

331

Spreading dynamics in complex networks  

NASA Astrophysics Data System (ADS)

Searching for influential spreaders in complex networks is an issue of great significance for applications across various domains, ranging from epidemic control, innovation diffusion, viral marketing, and social movement to idea propagation. In this paper, we first display some of the most important theoretical models that describe spreading processes, and then discuss the problem of locating both the individual and multiple influential spreaders respectively. Recent approaches in these two topics are presented. For the identification of privileged single spreaders, we summarize several widely used centralities, such as degree, betweenness centrality, PageRank, k-shell, etc. We investigate the empirical diffusion data in a large scale online social community—LiveJournal. With this extensive dataset, we find that various measures can convey very distinct information of nodes. Of all the users in the LiveJournal social network, only a small fraction of them are involved in spreading. For the spreading processes in LiveJournal, while degree can locate nodes participating in information diffusion with higher probability, k-shell is more effective in finding nodes with a large influence. Our results should provide useful information for designing efficient spreading strategies in reality.

Pei, Sen; Makse, Hernán A.

2013-12-01

332

Spark Spread Options Are Hot!  

Microsoft Academic Search

In a competitive electricity industry, natural gas power plant operators should dispatch a generation unit based on prevailing spot electricity and gas prices. This choice is best described by the “spread option” concepts often discussed in the financial arena. Ignorance of these concepts will inevitably lead to values lost.

Michael Hsu

1998-01-01

333

Using a Bull Call Spread  

E-print Network

The Bull Call Spread can be used to hedge against or to benefit from a rising market. The user buys a call option at a particular strike price and sells a call option at a higher strike price. Margin requirements, advantages and disadvantages...

Bevers, Stan; Amosson, Stephen H.; Waller, Mark L.; Dhuyvetter, Kevin C.

2008-10-07

334

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

335

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.

336

Spreading depression: a review of the clinical relevance  

Microsoft Academic Search

Spreading depression (SD), a transient reversible phenomenon with characteristic ionic, metabolic and hemodynamic changes, has been known for over 55 years. A vast number of studies into this mysterious experimental event provides evidence for SD involvement in brain pathophysiology. There is sufficient evidence to admit that SD plays an important role in some clinical disorders including migraine, cerebrovascular diseases, head

Ali Gorji

2001-01-01

337

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

338

Modelling the spread of Wolbachia in spatially heterogeneous environments.  

PubMed

The endosymbiont Wolbachia infects a large number of insect species and is capable of rapid spread when introduced into a novel host population. The bacteria spread by manipulating their hosts' reproduction, and their dynamics are influenced by the demographic structure of the host population and patterns of contact between individuals. Reaction-diffusion models of the spatial spread of Wolbachia provide a simple analytical description of their spatial dynamics but do not account for significant details of host population dynamics. We develop a metapopulation model describing the spatial dynamics of Wolbachia in an age-structured host insect population regulated by juvenile density-dependent competition. The model produces similar dynamics to the reaction-diffusion model in the limiting case where the host's habitat quality is spatially homogeneous and Wolbachia has a small effect on host fitness. When habitat quality varies spatially, Wolbachia spread is usually much slower, and the conditions necessary for local invasion are strongly affected by immigration of insects from surrounding regions. Spread is most difficult when variation in habitat quality is spatially correlated. The results show that spatial variation in the density-dependent competition experienced by juvenile host insects can strongly affect the spread of Wolbachia infections, which is important to the use of Wolbachia to control insect vectors of human disease and other pests. PMID:22675165

Hancock, Penelope A; Godfray, H Charles J

2012-11-01

339

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. PMID:23435239

Kramer, Tal; Enquist, Lynn W.

2013-01-01

340

A Lattice Model for Influenza Spreading  

PubMed Central

We construct a stochastic SIR model for influenza spreading on a D-dimensional lattice, which represents the dynamic contact network of individuals. An age distributed population is placed on the lattice and moves on it. The displacement from a site to a nearest neighbor empty site, allows individuals to change the number and identities of their contacts. The dynamics on the lattice is governed by an attractive interaction between individuals belonging to the same age-class. The parameters, which regulate the pattern dynamics, are fixed fitting the data on the age-dependent daily contact numbers, furnished by the Polymod survey. A simple SIR transmission model with a nearest neighbors interaction and some very basic adaptive mobility restrictions complete the model. The model is validated against the age-distributed Italian epidemiological data for the influenza A(H1N1) during the season, with sensible predictions for the epidemiological parameters. For an appropriate topology of the lattice, we find that, whenever the accordance between the contact patterns of the model and the Polymod data is satisfactory, there is a good agreement between the numerical and the experimental epidemiological data. This result shows how rich is the information encoded in the average contact patterns of individuals, with respect to the analysis of the epidemic spreading of an infectious disease. PMID:23717512

Liccardo, Antonella; Fierro, Annalisa

2013-01-01

341

A lattice model for influenza spreading.  

PubMed

We construct a stochastic SIR model for influenza spreading on a D-dimensional lattice, which represents the dynamic contact network of individuals. An age distributed population is placed on the lattice and moves on it. The displacement from a site to a nearest neighbor empty site, allows individuals to change the number and identities of their contacts. The dynamics on the lattice is governed by an attractive interaction between individuals belonging to the same age-class. The parameters, which regulate the pattern dynamics, are fixed fitting the data on the age-dependent daily contact numbers, furnished by the Polymod survey. A simple SIR transmission model with a nearest neighbors interaction and some very basic adaptive mobility restrictions complete the model. The model is validated against the age-distributed Italian epidemiological data for the influenza A(H1N1) during the [Formula: see text] season, with sensible predictions for the epidemiological parameters. For an appropriate topology of the lattice, we find that, whenever the accordance between the contact patterns of the model and the Polymod data is satisfactory, there is a good agreement between the numerical and the experimental epidemiological data. This result shows how rich is the information encoded in the average contact patterns of individuals, with respect to the analysis of the epidemic spreading of an infectious disease. PMID:23717512

Liccardo, Antonella; Fierro, Annalisa

2013-01-01

342

Chronic wasting disease of cervids.  

PubMed

Chronic wasting disease (CWD) has recently emerged in North America as an important prion disease of captive and free-ranging cervids (species in the deer family). CWD is the only recognized transmissible spongiform encephalopathy (TSE) affecting free-ranging species. Three cervid species, mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and Rocky Mountain elk (Cervus elaphus nelsoni), are the only known natural hosts of CWD. Endemic CWD is well established in southern Wyoming and northern Colorado, and has been present in this 'core area' for two decades or more. Apparently CWD has also infected farmed cervids in numerous jurisdictions, and has probably been endemic in North America's farmed deer and elk for well over a decade. Several free-ranging foci distant to the Colorado-Wyoming core area have been discovered since 2000, and new or intensified surveillance may well identify even more foci of infection. Whether all of the identified captive and free-ranging foci are connected via a common original exposure source remains undetermined. Some of this recently observed 'spread' may be attributable to improved detection or natural movements of infected deer and elk, but more distant range extensions are more likely caused by movements of infected captive deer and elk in commerce, or by some yet unidentified exposure risk factor. Research on CWD over the last 5 years has resulted in a more complete understanding of its pathogenesis and epidemiology. CWD is infectious, transmitting horizontally from infected to susceptible cervids. Early accumulation of PrP(CWD) in alimentary tract-associated lymphoid tissues during incubation suggests agent shedding in feces or saliva as plausible transmission routes. Residual infectivity in contaminated environments also appears to be important in sustaining epidemics. Improved tests allow CWD to be reliably diagnosed long before clinical signs appear. Implications of CWD are not entirely clear at this time. Natural transmission to humans or traditional domestic livestock seems relatively unlikely, but the possibility still evokes public concerns; impacts on wildlife resources have not been determined. Consequently, where CWD is not known to occur surveillance programs and regulations that prevent or reduce the likelihood that CWD will be introduced into these jurisdictions should be encouraged. Where CWD is known to occur, affected jurisdictions are conducting surveillance to estimate and monitor trends in geographic distribution and prevalence, managing deer and elk populations in attempts to limit spread, and developing and evaluating techniques for further controlling and perhaps eradicating CWD. Programs for addressing the challenges of CWD management will require interagency cooperation, commitment of funds and personnel, and applied research. Chronic wasting disease (CWD) is perhaps the most enigmatic of the naturally occurring prion diseases. Although recognized as a transmissible spongiform encephalopathy (TSE) since the late 1970s (Williams and Young 1980, 1982), interest in and concern about CWD has only recently emerged. CWD most closely resembles scrapie in sheep in most respects, but recent media and public reaction to CWD has been more reminiscent of that afforded to bovine spongiform encephalopathy (BSE) less than a decade ago. Yet, with the exception of transmissible mink encephalopathy (TME), CWD is the rarest of the known animal TSEs: fewer than 1,000 cases have been diagnosed worldwide, and all but two of these occurred in North America. CWD is unique among the TSEs in that it affects free-living species (Spraker et al. 1997; Miller et al. 2000). The three natural host species for CWD, mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and Rocky Mountain elk (Cervus elaphus nelsoni), are all in the family Cervidae and native to North America. Like scrapie, CWD is contagious: epidemics are self-sustaining in both captive and free-ranging cervid populations (Miller et al. 1998, 2000). The geographic extent of endemic CWD in free-ra

Miller, M W; Williams, E S

2004-01-01

343

PREVENTING DISEASES AND INFECTIONS  

NSDL National Science Digital Library

DESK Standard: Determine how communicable diseases are spread. . DATES: You can begin this activity on January 8. You should complete it by January 12. OBJECTIVE: Everyone wants to feel healthy because being sick is a drag! We have been discussing ways to prevent the spread of infections and diseases during class. There are many ...

Hughes, Mr.

2006-02-19

344

Reverse preferential spread in complex networks  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

345

[Infectious disease factors in swine--pathogenesis and control].  

PubMed

Infectious factorial diseases occur in all porcine age groups and are specially responsible for high mortality-rates in weaners and young feeder pigs affected by bronchopneumonia and enteritis. The pathogenesis of infectious factorial diseases is dominated by disease promoting factors of the pigs' environment as well as by false treatment with medicines and disinfectants. The control of infectious factorial diseases needs thorough examination as a basis for herd specific measures. Preventive measures should be completed in all pig herds by animal protective arrangements which are prescribed in the rules for prevention of cruelty to animals and contagious diseases. PMID:2513798

Bollwahn, W

1989-12-01

346

Epidemic and information co-spreading in adaptive social networks  

NASA Astrophysics Data System (ADS)

We model simultaneous evolution of an epidemic and information about the epidemic on an adaptive social network. The classical Susceptible-Infectious-Susceptible (SIS) model is extended. Susceptible and infectious nodes are each divided into informed and uninformed types. Informed nodes affect the network structure by rewiring their network connections adaptively to avoid disease exposure. The impacts of mass media information and communication on the disease spreading and network structure are explored, and stochastic simulations are compared with a moment closure approximation. When the rewiring rate is high, the infection and information levels of the population show periodic oscillations for certain ranges of contact rate, and the moment closure approximation predicts similar dynamics. The epidemic threshold in the presence of rewiring and information is considered. Our results indicate that information can play a significant role in minimizing disease spread.

Long, Yunhan

2012-02-01

347

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

348

Modelling the Wind-Borne Spread of Highly Pathogenic Avian Influenza Virus between Farms  

Microsoft Academic Search

A quantitative understanding of the spread of contaminated farm dust between locations is a prerequisite for obtaining much-needed insight into one of the possible mechanisms of disease spread between farms. Here, we develop a model to calculate the quantity of contaminated farm-dust particles deposited at various locations downwind of a source farm and apply the model to assess the possible

Amos Ssematimba; Thomas J. Hagenaars; Mart C. M. de Jong

2012-01-01

349

Tan F. Wong: Spread Spectrum & CDMA 4. Diversity in Spread Spectrum Diversity Reception in Spread Spectrum  

E-print Network

in free space, the loss in power, known as path loss, is given by L = ( 4#25;d #21; ) 2 ; (4.1) 4.1 #12 channel: Path Loss which describes the loss in power as the radio signal propagates in space Shadowing is on fading and how spread spectrum techniques can help to combat fading in wireless channels. 4.1 Path loss

Wong, Tan F.

350

Potential corridors and barriers for plague spread in central Asia  

PubMed Central

Background Plague (Yersinia pestis infection) is a vector-borne disease which caused millions of human deaths in the Middle Ages. The hosts of plague are mostly rodents, and the disease is spread by the fleas that feed on them. Currently, the disease still circulates amongst sylvatic rodent populations all over the world, including great gerbil (Rhombomys opimus) populations in Central Asia. Great gerbils are social desert rodents that live in family groups in burrows, which are visible on satellite images. In great gerbil populations an abundance threshold exists, above which plague can spread causing epizootics. The spatial distribution of the host species is thought to influence the plague dynamics, such as the direction of plague spread, however no detailed analysis exists on the possible functional or structural corridors and barriers that are present in this population and landscape. This study aims to fill that gap. Methods Three 20 by 20 km areas with known great gerbil burrow distributions were used to analyse the spatial distribution of the burrows. Object-based image analysis was used to map the landscape at several scales, and was linked to the burrow maps. A novel object-based method was developed – the mean neighbour absolute burrow density difference (MNABDD) – to identify the optimal scale and evaluate the efficacy of using landscape objects as opposed to square cells. Multiple regression using raster maps was used to identify the landscape-ecological variables that explain burrow density best. Functional corridors and barriers were mapped using burrow density thresholds. Cumulative resistance of the burrow distribution to potential disease spread was evaluated using cost distance analysis. A 46-year plague surveillance dataset was used to evaluate whether plague spread was radially symmetric. Results The burrow distribution was found to be non-random and negatively correlated with Greenness, especially in the floodplain areas. Corridors and barriers showed a mostly NWSE alignment, suggesting easier spreading along this axis. This was confirmed by the analysis of the plague data. Conclusions Plague spread had a predominantly NWSE direction, which is likely due to the NWSE alignment of corridors and barriers in the burrow distribution and the landscape. This finding may improve predictions of plague in the future and emphasizes the importance of including landscape analysis in wildlife disease studies. PMID:24171709

2013-01-01

351

A model for multiseasonal spread of verticillium wilt of lettuce.  

PubMed

Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of <5% have been detected in commercial lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per diseased plant, (ii) long-tail dispersal gradient, and (iii) low microsclerotia survival between lettuce crops-are present. PMID:24624952

Wu, B M; Subbarao, K V

2014-09-01

352

Measuring node spreading power by expected cluster degree  

E-print Network

Traditional metrics of node influence such as degree or betweenness identify highly influential nodes, but are rarely usefully accurate in quantifying the spreading power of nodes which are not. Such nodes are the vast majority of the network, and the most likely entry points for novel influences, be they pandemic disease or new ideas. Several recent works have suggested metrics based on path counting. The current work proposes instead using the expected number of infected-susceptible edges, and shows that this measure predicts spreading power in discrete time, continuous time, and competitive spreading processes simulated on large random networks and on real world networks. Applied to the Ugandan road network, it predicts that Ebola is unlikely to pose a pandemic threat.

Lawyer, Glenn

2012-01-01

353

Sea-Floor Spreading and Transform Faults  

ERIC Educational Resources Information Center

Presents the Crustal Evolution Education Project (CEEP) instructional module on Sea-Floor Spreading and Transform Faults. The module includes activities and materials required, procedures, summary questions, and extension ideas for teaching Sea-Floor Spreading. (SL)

Armstrong, Ronald E.; And Others

1978-01-01

354

An Opinion Spreading Model in Signed Networks  

NASA Astrophysics Data System (ADS)

The opinion spreading process can be modeled as the spread of an epidemic through a network, which assumes homogeneous relationships between individuals. However, positive and negative relationships in signed networks play different roles in the opinion spreading process, following the general rule that the same opinion will diffuse through friends, while the opposite opinion will likely emerge out of interactions between enemies. In order to explore opinion spreading behavior in signed networks, we proposed a simple opinion spreading model based on the susceptible-infected-recovered (SIR) epidemic model. Under the assumption of homogeneous mixing, we also analyzed the phase transition of opinion spreading in signed networks and found that critical spreading rates were closely related to the fraction of positive relationships in signed networks. Finally, we confirmed the correctness of our solutions using numerical simulations of the opinion spreading model in signed networks.

Li, Wei; Fan, Pengyi; Li, Pei; Wang, Hui; Pan, Yiguang

2013-05-01

355

First outbreak of sleeping disease in Switzerland: disease signs and virus characterization.  

PubMed

Sleeping disease is a contagious disease mainly of freshwater farmed rainbow trout, caused by salmonid alphavirus (SAV) Subtype 2. Here we describe the first case in Switzerland. Pathological changes ranged from acute pancreas necrosis to more chronic lesions with complete loss of exocrine pancreas and simultaneous degenerative, inflammatory and regenerative heart and muscle lesions. The partial sequencing of SAV E2 and nsp3 genes placed the Swiss SAV variant within the Subtype 2 clustering together with freshwater isolates from UK and continental Europe. Although mortality stayed low, growth rates were significantly reduced, making the disease economically relevant. PMID:25266904

Schmidt-Posthaus, Heike; Diserens, Nicolas; Jankowska Hjortaas, Monika; Knüsel, Ralph; Hirschi, Regula; Taksdal, Torunn

2014-09-30

356

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

357

Spread Spectrum Watermarking: Malicious Attacks and Counterattacks  

Microsoft Academic Search

Most watermarking methods for images and video have been proposed are based on ideas from spread spectrumradio communications, namely additive embedding of a (signal adaptive or non-adaptive) pseudo-noise watermarkpattern, and watermark recovery by correlation. Even methods that are not presented as spread spectrum methodsoften build on these principles. Recently, some scepticism about the robustness of spread spectrum watermarks hasarisen, specifically

Frank Hartung; Jonathan K. Su

1999-01-01

358

Spread spectrum watermarking: malicious attacks and counterattacks  

Microsoft Academic Search

Most watermarking methods for images and video have been proposed are based on ideas from spread spectrum radio communications, namely additive embedding of a (signal adaptive or non-adaptive) pseudo-noise watermark pattern, and watermark recovery by correlation. Even methods that are not presented as spread spectrum methods often build on these principles. Recently, some skepticism about the robustness of spread spectrum

Frank H. Hartung; Jonathan K. Su; Bernd Girod

1999-01-01

359

Assessing the role of spatial correlations during collective cell spreading  

PubMed Central

Spreading cell fronts are essential features of development, repair and disease processes. Many mathematical models used to describe the motion of cell fronts, such as Fisher's equation, invoke a mean–field assumption which implies that there is no spatial structure, such as cell clustering, present. Here, we examine the presence of spatial structure using a combination of in vitro circular barrier assays, discrete random walk simulations and pair correlation functions. In particular, we analyse discrete simulation data using pair correlation functions to show that spatial structure can form in a spreading population of cells either through sufficiently strong cell–to–cell adhesion or sufficiently rapid cell proliferation. We analyse images from a circular barrier assay describing the spreading of a population of MM127 melanoma cells using the same pair correlation functions. Our results indicate that the spreading melanoma cell populations remain very close to spatially uniform, suggesting that the strength of cell–to–cell adhesion and the rate of cell proliferation are both sufficiently small so as not to induce any spatial patterning in the spreading populations. PMID:25026987

Treloar, Katrina K.; Simpson, Matthew J.; Binder, Benjamin J.; McElwain, D. L. Sean; Baker, Ruth E.

2014-01-01

360

Effects of internal fluctuations on the spreading of Hantavirus C. Escudero,1  

E-print Network

Effects of internal fluctuations on the spreading of Hantavirus C. Escudero,1 J. Buceta,1,2, * F. J between out- breaks of the disease and seasonal changes was explored by Buceta et al. [6]. This collection

Lindenberg, Katja

361

Diabetes and Hepatitis B Vaccination  

MedlinePLUS

Diabetes and Hepatitis B Vaccination Information for Diabetes Educators What is hepatitis B? Hepatitis B is a contagious liver disease that ... as liver failure or liver cancer. How is hepatitis B spread? The hepatitis B virus is usually ...

362

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  

Microsoft Academic Search

n p 24 n p 7 n p 1 n p 1 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

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

2001-01-01

363

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. PMID:269203

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

1977-01-01

364

Antimalarial drug resistance: a review of the biology and strategies to delay emergence and spread  

PubMed Central

The emergence of resistance to former first-line antimalarial drugs has been an unmitigated disaster. In recent years, artemisinin class drugs have become standard and they are considered an essential tool for helping to eradicate the disease. However, their ability to reduce morbidity and mortality and to slow transmission requires the maintenance of effectiveness. Recently, an artemisinin delayed-clearance phenotype was described. This is believed to be the precursor to resistance and threatens local elimination and global eradication plans. Understanding how resistance emerges and spreads is important for developing strategies to contain its spread. Resistance is the result of two processes: (i) drug selection of resistant parasites; and (ii) the spread of resistance. In this review, we examine the factors that lead to both drug selection and the spread of resistance. We then examine strategies for controlling the spread of resistance, pointing out the complexities and deficiencies in predicting how resistance will spread. PMID:23394809

Klein, E.Y.

2013-01-01

365

Quarantine generated phase transition in epidemic spreading  

NASA Astrophysics Data System (ADS)

We study the critical effect of quarantine on the propagation of epidemics on an adaptive network of social contacts. For this purpose, we analyze the susceptible-infected-recovered (SIR) model in the presence of quarantine, where susceptible individuals protect themselves by disconnecting their links to infected neighbors with probability w, and reconnecting them to other susceptible individuals chosen at random. Starting from a single infected individual, we show by an analytical approach and simulations that there is a phase transition at a critical rewiring (quarantine) threshold wc separating a phase (wdisease reaches a large fraction of the population, from a phase (w >= wc) where the disease does not spread out. We find that in our model the topology of the network strongly affects the size of the propagation, and that wc increases with the mean degree and heterogeneity of the network. We also find that wc is reduced if we perform a preferential rewiring, in which the rewiring probability is proportional to the degree of infected nodes.

Dicksion, Mark; Lagorio, Cecilia; Vazquez, F.; Braunstein, L.; Macri, P. A.; Migueles, M. V.; Havlin, S.; Stanley, H. E.

2011-03-01

366

EDHF: spreading the influence of the endothelium  

PubMed Central

Our view of the endothelium was transformed around 30 years ago, from one of an inert barrier to that of a key endocrine organ central to cardiovascular function. This dramatic change followed the discoveries that endothelial cells (ECs) elaborate the vasodilators prostacyclin and nitric oxide. The key to these discoveries was the use of the quintessentially pharmacological technique of bioassay. Bioassay also revealed endothelium-derived hyperpolarizing factor (EDHF), particularly important in small arteries and influencing blood pressure and flow distribution. The basic idea of EDHF as a diffusible factor causing smooth muscle hyperpolarization (and thus vasodilatation) has evolved into one of a complex pathway activated by endothelial Ca2+ opening two Ca2+-sensitive K+-channels, KCa2.3 and KCa3.1. Combined application of apamin and charybdotoxin blocked EDHF responses, revealing the critical role of these channels as iberiotoxin was unable to substitute for charybdotoxin. We showed these channels are arranged in endothelial microdomains, particularly within projections towards the adjacent smooth muscle, and close to interendothelial gap junctions. Activation of KCa channels hyperpolarizes ECs, and K+ efflux through them can act as a diffusible ‘EDHF’ stimulating Na+/K+-ATPase and inwardly rectifying K-channels. In parallel, hyperpolarizing current can spread from the endothelium to the smooth muscle through myoendothelial gap junctions upon endothelial projections. The resulting radial hyperpolarization mobilized by EDHF is complemented by spread of hyperpolarization along arteries and arterioles, effecting distant dilatation dependent on the endothelium. So the complexity of the endothelium still continues to amaze and, as knowledge evolves, provides considerable potential for novel approaches to modulate blood pressure. LINKED ARTICLES This article is part of a themed issue on Vascular Endothelium in Health and Disease. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.164.issue-3 PMID:21133895

Garland, Christopher J; Hiley, C Robin; Dora, Kim A

2011-01-01

367

A statistical model to assess the risk of communicable diseases associated with multiple exposures in healthcare settings  

PubMed Central

Background The occurrence of communicable diseases (CD) depends on exposure to contagious persons. The effects of exposure to CD are delayed in time and contagious persons remain contagious for several days during which their contagiousness varies. Moreover when multiple exposures occur, it is difficult to know which exposure is associated with the CD. Methods A statistical model at the individual level is presented to estimate the risk of CD to patients, in healthcare settings, with multiple observed exposures to other patients and healthcare workers and unobserved exposures to unobserved or unobservable sources. The model explores the delayed effect of observed exposure, of source contagiousness and of unobserved exposure. It was applied to data on influenza-like illness (ILI) among patients in a university hospital during 3 influenza seasons: from 2004 to 2007. Over a total of 138,411 patients-days of follow-up, 64 incident ILI cases were observed among 21,519 patients at risk of ILI. Results The ILI risk per 10,000 patients-days associated with observed exposure was about 129.1 (95% Credible Interval (CrI): 84.5, 182.9) and was associated at 72% with exposures to patients or healthcare workers 1 day earlier and at 41% with the 1st day of source contagiousness. The ILI risk associated with unobserved exposure was 0.8 (95% CrI: 0.3, 1.6) per 10,000 patients-days in non-epidemic situation in the community and 4.3 (95% CrI: 0.4, 11.0) in epidemic situation. Conclusions The model could be an interesting epidemiological tool to further assess the relative contributions of observed and unobserved exposures to CD risk in healthcare settings. PMID:23425160

2013-01-01

368

Wet climate and transportation routes accelerate spread of human plague.  

PubMed

Currently, large-scale transmissions of infectious diseases are becoming more closely associated with accelerated globalization and climate change, but quantitative analyses are still rare. By using an extensive dataset consisting of date and location of cases for the third plague pandemic from 1772 to 1964 in China and a novel method (nearest neighbour approach) which deals with both short- and long-distance transmissions, we found the presence of major roads, rivers and coastline accelerated the spread of plague and shaped the transmission patterns. We found that plague spread velocity was positively associated with wet conditions (measured by an index of drought and flood events) in China, probably due to flood-driven transmission by people or rodents. Our study provides new insights on transmission patterns and possible mechanisms behind variability in transmission speed, with implications for prevention and control measures. The methodology may also be applicable to studies of disease dynamics or species movement in other systems. PMID:24523275

Xu, Lei; Stige, Leif Chr; Kausrud, Kyrre Linné; Ben Ari, Tamara; Wang, Shuchun; Fang, Xiye; Schmid, Boris V; Liu, Qiyong; Stenseth, Nils Chr; Zhang, Zhibin

2014-04-01

369

Epidemic spread in adaptive networks with multitype agents  

NASA Astrophysics Data System (ADS)

In this paper we study the epidemic spread in adaptive networks with multitype agents. We assume that the infection probability as well as the rewiring probability between agents is type-dependent. Under this assumption we analyze a system of M-type networks with mean-field approximation. These general expressions apply to networks with various choices of infection mechanisms and rewiring rules. We explicitly evaluate the infection level for two-type networks with intratype/intertype infecting and rewiring and investigate their impacts on the epidemic threshold. By plotting the bifurcation diagram for various parameters, we find a bistability region where both the disease-free state and the endemic state co-exist for appropriate rewiring dynamics. The area of each phase depends on the corresponding interaction modes. We show that consistency between infecting and rewiring modes speeds up the disease spread, while inconsistency contributes to halting the outbreak.

Wang, Bing; Cao, Lang; Suzuki, Hideyuki; Aihara, Kazuyuki

2011-01-01

370

Sarcoma spreads primarily through the vascular system: are there biomarkers associated with vascular spread?  

PubMed

Sarcomas are a heterogeneous group of tumors with specific molecular characteristics and currently classified on the basis of their tissue of origin and histologic appearance. Except for epithelioid sarcoma, clear cell sarcoma, angiosarcoma and rhabdomyosarcoma, which may spread to regional lymph nodes, the other histotypes spread via the vascular system to the lungs most of the time. A variety of molecular approaches, including gene expression profiling, have identified candidate biomarkers and generated insights into sarcoma biology. The comprehension of the pathogenesis of this malignancy according to the mesenchymal stem cell hypothesis parallels the description of several molecular pathways deregulated in sarcoma. Individuation of vascular spread biomarkers is actually focused on the study of factors involved both in hemostasis and angiogenesis. Interestingly the microenvironment of sarcomas showed the very same mesenchymal origin of the surrounding stromal cells. The presence of circulating tumor cells and miRNAs in blood samples of sarcoma patients represents the possibility not only to better stratify patients group according to the prognosis but also to tailor new individualized therapy. So, it could be predicted that some genes expressed in a specific sarcoma might have prognostic significance or therapeutic targeting potential and molecular targets can be identified in the tumor or in the tumor microenvironment. Therefore the initial evaluation of a sarcoma patient should include in-depth genetic evaluation including karyotyping and c-DNA/protein expression profiling. The chemokine signaling demonstrated to be deeply implicated in sarcoma development as well as to have a significant role in development of metastatic disease, especially in directing tumor cells towards the preferential sites of metastases in sarcoma, lung and bone. It is unsolved if the blood stream is a more favorable environment compared to lymphatic or if lymph nodes are more efficient in destroying metastatic sarcoma cells. But the comprehension of the regulatory mechanisms of the behavior of mesenchymal malignant tumors is at its dawn. PMID:22699363

Pennacchioli, Elisabetta; Tosti, Giulio; Barberis, Massimo; De Pas, Tommaso M; Verrecchia, Francesco; Menicanti, Claudia; Testori, Alessandro; Mazzarol, Giovanni

2012-10-01

371

Global stability and persistence in LG-Holling type II diseased predator ecosystems  

PubMed Central

A Leslie–Gower–Holling type II model is modified to introduce a contagious disease in the predator population, assuming that disease cannot propagate to the prey. All the system’s equilibria are determined and the behaviour of the system near them is investigated. The main mathematical issues are global stability and bifurcations for some of the equilibria, together with sufficient conditions for persistence of the ecosystem. Counterintuitive results on the role played by intraspecific competition are highlighted. PMID:22210964

Sarwardi, Sahabuddin; Haque, Mainul

2010-01-01

372

Inhibition of Foot-and-Mouth Disease Virus Infections in Cell Cultures with Antisense Morpholino Oligomers  

Microsoft Academic Search

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed ungulates that can lead to severe losses in the livestock production and export industries. Although vaccines have been extensively used to control FMD, there is no antiviral therapy available to treat ongoing infections with FMD virus (FMDV). Six peptide-conjugated morpholino oligomers (PPMOs) with sequences complementary to various 21-nucleo- tide

Ariel Vagnozzi; David A. Stein; Patrick L. Iversen; Elizabeth Rieder

2007-01-01

373

Cost-effectiveness of diagnostic strategies using quantitative real-time PCR and bacterial culture to identify contagious mastitis cases in large dairy herds.  

PubMed

Diagnostic strategies to detect contagious mastitis caused by Mycoplasma bovis, Staphylococcus aureus, and Streptococcus agalactiae in dairy herds during an outbreak have been minimally studied with regard to cost and diagnostic sensitivity. The objective of this cross-sectional study was to compare the cost-effectiveness of diagnostic strategies for identification of infected cows in two California dairy herds during contagious mastitis outbreaks. M. bovis was investigated in a subset of a herd (n=1210 cows) with an estimated prevalence of 2.8% (95% CI=1.9, 3.7), whereas Staph. aureus and Strep. agalactiae were studied in a second herd (n=351 cows) with an estimated prevalence of 3.4% (95% CI=1.5, 5.3) and 16.8% (95% CI=12.9, 20.7), respectively. Diagnostic strategies involved a combination of testing stages that utilized bacterial culture, quantitative real-time PCR (qPCR), or both. Strategies were applied to individual or pooled samples of 5, 10, 50 or 100 samples. Culture was considered the gold standard for sensitivity estimation of each strategy. The reference strategy was the strategy with the lowest cost per culture-positive cow which for both M. bovis and Strep. agalactiae consisted of 2 stages, culture of samples in pools of 5 followed by culture of individual samples in positive pools with a sensitivity of 73.5% (95% CI: 55.6, 87.1) and 96.6% (95% CI: 27.7, 84.8), respectively. The reference strategy for Staph. aureus consisted of 3 stages, culture of individual samples in pools of 100 (stage 1), culture constituents of those positive from stage 1 in pools of 5 (stage 2), culture constituents of those positive from stage 2 individually (stage 3) which resulted in a sensitivity of 58.3% (95% CI: 88.3, 99.6). The most cost-effective alternative to the reference strategy was whole herd milk culture for all 3 pathogens. QPCR testing was a component of the second most cost-effective alternative for M. bovis and the third most cost-effective alternatives for the 3 pathogens. A stochastic model was used to assess the effect of prevalence or herd size on the cost-effectiveness of diagnostic strategies. In the current study, increasing the prevalence of mastitis did not alter the ranking of strategies by cost-effectiveness. However, larger herds could benefit from testing larger pools such as 50 or 100 samples to improve cost-effectiveness. Several diagnostic strategy options exist to identify contagious mastitis in herds, decisions should be based on cost and sensitivity of the strategies available. PMID:24485275

Murai, Kiyokazu; Lehenbauer, Terry W; Champagne, John D; Glenn, Kathy; Aly, Sharif S

2014-03-01

374

Spread and SpreadRecorder An Architecture for Data Distribution  

NASA Technical Reports Server (NTRS)

The Space Acceleration Measurement System (SAMS) project at the NASA Glenn Research Center (GRC) has been measuring the microgravity environment of the space shuttle, the International Space Station, MIR, sounding rockets, drop towers, and aircraft since 1991. The Principle Investigator Microgravity Services (PIMS) project at NASA GRC has been collecting, analyzing, reducing, and disseminating over 3 terabytes of collected SAMS and other microgravity sensor data to scientists so they can understand the disturbances that affect their microgravity science experiments. The years of experience with space flight data generation, telemetry, operations, analysis, and distribution give the SAMS/ PIMS team a unique perspective on space data systems. In 2005, the SAMS/PIMS team was asked to look into generalizing their data system and combining it with the nascent medical instrumentation data systems being proposed for ISS and beyond, specifically the Medical Computer Interface Adapter (MCIA) project. The SpreadRecorder software is a prototype system developed by SAMS/PIMS to explore ways of meeting the needs of both the medical and microgravity measurement communities. It is hoped that the system is general enough to be used for many other purposes.

Wright, Ted

2006-01-01

375

A general method for identifying node spreading influence via the adjacent matrix and spreading rate  

E-print Network

With great theoretical and practical significance, identifying the node spreading influence of complex network is one of the most promising domains. So far, various topology-based centrality measures have been proposed to identify the node spreading influence in a network. However, the node spreading influence is a result of the interplay between the network topology structure and spreading dynamics. In this paper, we build up the systematic method by combining the network structure and spreading dynamics to identify the node spreading influence. By combining the adjacent matrix $A$ and spreading parameter $\\beta$, we theoretical give the node spreading influence with the eigenvector of the largest eigenvalue. Comparing with the Susceptible-Infected-Recovered (SIR) model epidemic results for four real networks, our method could identify the node spreading influence more accurately than the ones generated by the degree, K-shell and eigenvector centrality. This work may provide a systematic method for identifyi...

Lin, Jian-Hong; Guo, Qiang

2014-01-01

376

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.  

PubMed

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 isolate of non-B genotype (CH cases). All samples were bacteriologically analysed and Staph. aureus genotyping carried out using a ribosomal spacer-PCR. Cow and quarter prevalences of Staph. aureus, CNS and Streptococcus spp. differed significantly between PH and CH groups. PH cases were highly associated with decreased cow prevalences of CNS and Streptococcus spp. These altered prevalences also contributed significantly to the identification of problem herds without resorting to genotyping. Common herd-level risk factors did not explain the difference between the prevalences in PH and CH cases. PMID:20591704

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

2011-06-01

377

An adenovirus vectored mucosal adjuvant augments protection of mice immunized intranasally with an adenovirus-vectored foot-and-mouth disease virus subunit vaccine.  

PubMed

Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen that causes severe morbidity and economic losses to the livestock industry in many countries. The oral and respiratory mucosae are the main ports of entry of FMDV, so the stimulation of local immunity in these tissues may help prevent initial infection and viral spread. E. coli heat-labile enterotoxin (LT) has been described as one of the few molecules that have adjuvant activity at mucosal surfaces. The objective of this study was to evaluate the efficacy of replication-defective adenovirus 5 (Ad5) vectors encoding either of two LT-based mucosal adjuvants, LTB or LTR72. These vectored adjuvants were delivered intranasally to mice concurrent with an Ad5-FMDV vaccine (Ad5-A24) to assess their ability to augment mucosal and systemic humoral immune responses to Ad5-A24 and protection against FMDV. Mice receiving Ad5-A24 plus Ad5-LTR72 had higher levels of mucosal and systemic neutralizing antibodies than those receiving Ad5-A24 alone or Ad5-A24 plus Ad5-LTB. The vaccine plus Ad5-LTR72 group also demonstrated 100% survival after intradermal challenge with a lethal dose of homologous FMDV serotype A24. These results suggest that Ad5-LTR72 could be used as an important tool to enhance mucosal and systemic immunity against FMDV and potentially other pathogens with a common route of entry. PMID:23499593

Alejo, Diana M; Moraes, Mauro P; Liao, Xiaofen; Dias, Camila C; Tulman, Edan R; Diaz-San Segundo, Fayna; Rood, Debra; Grubman, Marvin J; Silbart, Lawrence K

2013-04-26

378

CTLA-4 downregulates epitope spreading and mediates remission in relapsing experimental autoimmune encephalomyelitis.  

PubMed

During the progression of relapsing experimental autoimmune encephalomyelitis (R-EAE), in SJL mice, disease relapses are mediated by T cells specific for non-cross-reactive myelin epitopes, a process termed 'epitope spreading'. CTLA-4, a negative regulator of T cell function modulates R-EAE, in that CTLA-4 blockade exacerbates clinical R-EAE. Herein, we show that CTLA-4-mediated signaling negatively regulates the dynamic spread of autoreactive T cell responses during the course of autoimmune disease. Anti-CTLA-4 mAb, administration at various points during the progression of R-EAE exacerbated subsequent clinical disease and enhanced T cell reactivity to both inducing and relapse-associated epitopes. In addition, CTLA-4 blockade during acute disease inhibited clinical remission. Thus, CTLA-4-mediated events are critical for intrinsic regulation of epitope spreading during autoimmune disease. PMID:10996219

Karandikar, N J; Eagar, T N; Vanderlugt, C L; Bluestone, J A; Miller, S D

2000-09-22

379

Spreading sequences for multicarrier CDMA systems  

Microsoft Academic Search

The paper contains an analysis of the basic criteria for the selection of spreading sequences for the multicarrier CDMA (MC-CDMA) systems with spectrum spreading in the frequency domain. It is shown that the time-domain crosscorrelation function between the spreading sequences is not a proper interference measure for the asynchronous MC-CDMA users. Therefore, the spectral correlation function is introduced and, together

B. M. Popovic

1999-01-01

380

Clinico-pathological significance of extra-nodal spread in special types of breast cancer  

PubMed Central

Objective To investigate the significance of extra-nodal spread in special histological sub-types of breast cancer and the relationship of such spread with prognostic parameters. Methods A total of 303 breast cancer cases were classified according to tumor type, and each tumor group was subdivided according to age, tumor diameter, lymph node metastasis, extra-nodal spread, vein invasion in the adjacent soft tissue, distant metastasis, and immunohistochemical characteristics [estrogen receptor (ER), progesterone receptor (PR) existence, p53, c-erbB-2, and proliferative rate (Ki-67)]. The 122 cases with extra-nodal spread were clinically followed up. Results An extra-nodal spread was observed in 40% (122 cases) of the 303 breast cancer cases. The spread most frequently presented in micro papillary carcinoma histological sub-type (40 cases, 75%), but least frequently presents in mucinous carcinoma (2 cases, 8%). Patients with extra-nodal spread had a high average number of metastatic lymph nodes (8.3) and a high distant metastasis rate (38 cases, 31%) compared with patients without extra-nodal spread. Conclusion The existence of extra-nodal spread in the examined breast cancer sub-types has predictive value in forecasting the number of metastatic lymph nodes and the disease prognosis. PMID:25009753

Kaygusuz, Ecmel Isik; Cetiner, Handan; Yavuz, Hulya

2014-01-01

381

Epidemic spreading on hierarchical geographical networks with mobile agents  

NASA Astrophysics Data System (ADS)

Hierarchical geographical traffic networks are critical for our understanding of scaling laws in human trajectories. Here, we investigate the susceptible-infected epidemic process evolving on hierarchical networks in which agents randomly walk along the edges and establish contacts in network nodes. We employ a metapopulation modeling framework that allows us to explore the contagion spread patterns in relation to multi-scale mobility behaviors. A series of computer simulations revealed that a shifted power-law-like negative relationship between the peak timing of epidemics ?0 and population density, and a logarithmic positive relationship between ?0 and the network size, can both be explained by the gradual enlargement of fluctuations in the spreading process. We employ a semi-analytical method to better understand the nature of these relationships and the role of pertinent demographic factors. Additionally, we provide a quantitative discussion of the efficiency of a border screening procedure in delaying epidemic outbreaks on hierarchical networks, yielding a rather limited feasibility of this mitigation strategy but also its non-trivial dependence on population density, infector detectability, and the diversity of the susceptible region. Our results suggest that the interplay between the human spatial dynamics, network topology, and demographic factors can have important consequences for the global spreading and control of infectious diseases. These findings provide novel insights into the combined effects of human mobility and the organization of geographical networks on spreading processes, with important implications for both epidemiological research and health policy.

Han, Xiao-Pu; Zhao, Zhi-Dan; Hadzibeganovic, Tarik; Wang, Bing-Hong

2014-05-01

382

Rapid Sequential Spread of Two Wolbachia Variants in Drosophila simulans  

PubMed Central

The maternally inherited intracellular bacteria Wolbachia can manipulate host reproduction in various ways that foster frequency increases within and among host populations. Manipulations involving cytoplasmic incompatibility (CI), where matings between infected males and uninfected females produce non-viable embryos, are common in arthropods and produce a reproductive advantage for infected females. CI was associated with the spread of Wolbachia variant wRi in Californian populations of Drosophila simulans, which was interpreted as a bistable wave, in which local infection frequencies tend to increase only once the infection becomes sufficiently common to offset imperfect maternal transmission and infection costs. However, maternally inherited Wolbachia are expected to evolve towards mutualism, and they are known to increase host fitness by protecting against infectious microbes or increasing fecundity. We describe the sequential spread over approximately 20 years in natural populations of D. simulans on the east coast of Australia of two Wolbachia variants (wAu and wRi), only one of which causes significant CI, with wRi displacing wAu since 2004. Wolbachia and mtDNA frequency data and analyses suggest that these dynamics, as well as the earlier spread in California, are best understood as Fisherian waves of favourable variants, in which local spread tends to occur from arbitrarily low frequencies. We discuss implications for Wolbachia-host dynamics and coevolution and for applications of Wolbachia to disease control. PMID:24068927

Kriesner, Peter; Hoffmann, Ary A.; Lee, Siu F.; Turelli, Michael; Weeks, Andrew R.

2013-01-01

383

A combination of improved differential and global RNA-seq reveals pervasive transcription initiation and events in all stages of the life-cycle of functional RNAs in Propionibacterium acnes, a major contributor to wide-spread human disease  

PubMed Central

Background Sequencing of the genome of Propionibacterium acnes produced a catalogue of genes many of which enable this organism to colonise skin and survive exposure to the elements. Despite this platform, there was little understanding of the gene regulation that gives rise to an organism that has a major impact on human health and wellbeing and causes infections beyond the skin. To address this situation, we have undertaken a genome–wide study of gene regulation using a combination of improved differential and global RNA-sequencing and an analytical approach that takes into account the inherent noise within the data. Results We have produced nucleotide-resolution transcriptome maps that identify and differentiate sites of transcription initiation from sites of stable RNA processing and mRNA cleavage. Moreover, analysis of these maps provides strong evidence for ‘pervasive’ transcription and shows that contrary to initial indications it is not biased towards the production of antisense RNAs. In addition, the maps reveal an extensive array of riboswitches, leaderless mRNAs and small non-protein-coding RNAs alongside vegetative promoters and post-transcriptional events, which includes unusual tRNA processing. The identification of such features will inform models of complex gene regulation, as illustrated here for ribonucleotide reductases and a potential quorum-sensing, two-component system. Conclusions The approach described here, which is transferable to any bacterial species, has produced a step increase in whole-cell knowledge of gene regulation in P. acnes. Continued expansion of our maps to include transcription associated with different growth conditions and genetic backgrounds will provide a new platform from which to computationally model the gene expression that determines the physiology of P. acnes and its role in human disease. PMID:24034785

2013-01-01

384

The foot and mouth disease network in the southern cone of South America: an example of regional governance.  

PubMed

The fact that foot and mouth disease is highly contagious, easily spread and of major commercial importance makes it a redoubtable challenge for animal health in South American countries and the world over. A number of factors impact directly on the effectiveness of national programmes to eradicate foot and mouth disease. Therefore, in order to meet the challenges posed by today's globalised world, it is of the utmost importance that national level eradication programmes be considered state policies and that they be the subject of broad political agreement at the highest level and consolidated as regional programmes between national Veterinary Services. The programmes, agreements and technical cooperation projects established jointly by Member Countries of the Southern Common Market (MERCOSUR) were a key factor in building management capacity to control foot and mouth disease in the area. Another key factor has been a partnership with one of the most sensitive sectors--the private production sector. Its active and responsible participation in operational functions has done much to strengthen and ensure the competitive development of South American countries and consolidate their role as global beef exporters. However, to prevent further outbreaks it is essential to maintain and reinforce the structure of national programmes and to have strong and highly trained Veterinary Services and sufficient funding to ensure efficient and sustainable plans. These plans must enable Veterinary Services, by means of good governance, to implement effective measures in the areas of animal health and international trade in animals and animal products/by-products, thereby achieving rapid and more equitable social and economic development. PMID:23413740

Corrales Irrazábal, H A

2012-08-01

385

Environmental performance indicators of organic spreading machines  

E-print Network

1 Environmental performance indicators of organic spreading machines M. Rousselet1 *, J. C. Roux1 to French spreading machines. The task consists in defining relevant indicators specifically for spreaders indicator before and after improvement on the machine. Keywords: Environmental Performance Indicator

Paris-Sud XI, Université de

386

Epidemic spreading through direct and indirect interactions  

NASA Astrophysics Data System (ADS)

In this paper we study the susceptible-infected-susceptible epidemic dynamics, considering a specialized setting where popular places (termed passive entities) are visited by agents (termed active entities). We consider two types of spreading dynamics: direct spreading, where the active entities infect each other while visiting the passive entities, and indirect spreading, where the passive entities act as carriers and the infection is spread via them. We investigate in particular the effect of selection strategy, i.e., the way passive entities are chosen, in the spread of epidemics. We introduce a mathematical framework to study the effect of an arbitrary selection strategy and derive formulas for prevalence, extinction probabilities, and epidemic thresholds for both indirect and direct spreading. We also obtain a very simple relationship between the extinction probability and the prevalence. We pay special attention to preferential selection and derive exact formulas. The analysis reveals that an increase in the diversity in the selection process lowers the epidemic thresholds. Comparing the direct and indirect spreading, we identify regions in the parameter space where the prevalence of the indirect spreading is higher than the direct one.

Ganguly, Niloy; Krueger, Tyll; Mukherjee, Animesh; Saha, Sudipta

2014-09-01

387

Delaying the International Spread of Pandemic Influenza  

Microsoft Academic Search

Background The recent emergence of hypervirulent subtypes of avian influenza has underlined the potentially devastating effects of pandemic influenza. Were such a virus to acquire the ability to spread efficiently between humans, control would almost certainly be hampered by limited vaccine supplies unless global spread could be substantially delayed. Moreover, the large increases that have occurred in international air travel

Ben S. Cooper; Richard J. Pitman; W. John Edmunds; Nigel J. Gay

2006-01-01

388

Prediction of Fire Spread Following Nuclear Explosions  

E-print Network

Prediction of Fire Spread Following Nuclear Explosions Craig C. Chandler, Theodore G. Storey spread following nuclear explosions. Berkeley, Calif., Pacific SW. Forest & Range Expt Sta. 110 pp nuclear explosions. Berkeley, Calif., Pacific SW. Forest & Range Expt Sta. 110 pp., illus. (U.S. Forest

Standiford, Richard B.

389

Meningococcal Disease: Causes and Transmission  

MedlinePLUS

... Campaign Podcast: Meningitis Immunization for Adolescents Meningitis Causes & Transmission Share Compartir Causes Meningococcal disease is caused by ... certain illnesses, which are known as meningococcal disease. Transmission Neisseria meningitidis bacteria are spread through the exchange ...

390

Reactive spreading in ceramic/metal systems  

SciTech Connect

Reactive spreading, in which a chemically active element is added to promote wetting of noble metals on nonmetallic materials, is evaluated mechanistically. Theories for the energetics and kinetics of the steps involved in spreading are outlined to permit comparison to the steps in the compound formation that typically accompanies reactive wetting. These include: fluid flow, active metal adsorption, including nonequilibrium effects, and triple line ridging. They can all be faster than compound nucleation under certain conditions. This analysis plus assessment of recently reported experiments on metal/ceramic systems lead to a focus on those conditions under which spreading proceeds ahead of the actual formation of a new phase at the interface. This scenario may be more typical than commonly believed, and perhaps is the most effective situation leading to enhanced spreading. A rationale for the slow spreading rates plus the pervasive variability and hysteresis observed during high temperature wetting also emerges.

Saiz, Eduardo; Cannon, Rowland M.; Tomsia, Antoni P.

2000-11-06

391

Projecting rates of spread for invasive species.  

PubMed

All else being equal, the faster an invading species spreads, the more dangerous its invasion. The projection of spread rate therefore ought to be a central part of the determination of invasion risk. Originally formulated in the 1970s to describe the spatial spread of advantageous alleles, integrodifference equation (IDE) models have since been co-opted by population biologists to describe the spread of populations. More recently, they have been modified to include population structure and environmental variability. We review how IDE models are formulated, how they are parameterized, and how they can be analyzed to project spread rates and the sensitivity of those rates to changes in model parameters. For illustrative purposes, we apply these models to Cytisus scoparius, a large shrub in the legume family that is considered a noxious invasive species in eastern and western North America, Chile, Australia, and New Zealand. PMID:15357802

Neubert, Michael G; Parker, Ingrid M

2004-08-01

392

Evaluation of three 3ABC ELISAs for foot-and-mouth disease non-structural antibodies using latent class analysis  

Microsoft Academic Search

BACKGROUND: Foot-and-mouth disease (FMD) is a highly contagious viral disease of even-toed ungulates. Serological diagnosis\\/surveillance of FMD presents several problems as there are seven serotypes worldwide and in the event of vaccination it may be necessary to be able to identify FMD infected\\/exposed animals irrespective of their vaccination status. The recent development of non-structural 3ABC protein (NSP) ELISA tests has

Barend M deC Bronsvoort; Nils Toft; Ingrid E Bergmann; Karl-Johan Sørensen; John Anderson; Viviane Malirat; Vincent N Tanya; Kenton L Morgan

2006-01-01

393

Modeling the effects of social impact on epidemic spreading in complex networks  

NASA Astrophysics Data System (ADS)

We investigate by mean-field analysis and extensive simulations the effects of social impact on epidemic spreading in various typical networks with two types of nodes: active nodes and passive nodes, of which the behavior patterns are modeled according to the social impact theory. In this study, nodes are not only the media to spread the virus, but also disseminate their opinions on the virus-whether there is a need for certain self-protection measures to be taken to reduce the risk of being infected. Our results indicate that the interaction between epidemic spreading and opinion dynamics can have significant influences on the spreading of infectious diseases and related applications, such as the implementation of prevention and control measures against the infectious diseases.

Ni, Shunjiang; Weng, Wenguo; Zhang, Hui

2011-11-01

394

H1N1 (swine flu) Information for Students, Faculty & Staff There have been confirmed H1N1 cases and a death in Tennessee. The Center for Disease Control (CDC)  

E-print Network

and a death in Tennessee. The Center for Disease Control (CDC) reports that H1N1 is contagious infected with this virus also have reported diarrhea and vomiting. Severe illnesses and death has occurred? Illness with the new H1N1 virus has ranged from mild to severe. While most people who have been sick have

Karsai, Istvan

395

SIHR rumor spreading model in social networks  

NASA Astrophysics Data System (ADS)

There are significant differences between rumor spreading and epidemic spreading in social networks, especially with consideration of the mutual effect of forgetting and remembering mechanisms. In this paper, a new rumor spreading model, Susceptible-Infected-Hibernator-Removed (SIHR) model, is developed. The model extends the classical Susceptible-Infected-Removed (SIR) rumor spreading model by adding a direct link from ignorants to stiflers and a new kind of people-Hibernators. We derive mean-field equations that describe the dynamics of the SIHR model in social networks. Then a steady-state analysis is conducted to investigate the final size of the rumor spreading under various spreading rate, stifling rate, forgetting rate, and average degree of the network. We discuss the spreading threshold and find the relationship between the final size of the rumor and two probabilities. Also Runge-Kutta method is used for numerical simulation which shows that the direct link from the ignorants to the stiflers advances the rumor terminal time and reduces the maximum rumor influence. Moreover, the forgetting and remembering mechanisms of hibernators postpone the rumor terminal time and reduce the maximum rumor influence.

Zhao, Laijun; Wang, Jiajia; Chen, Yucheng; Wang, Qin; Cheng, Jingjing; Cui, Hongxin

2012-04-01

396

Information spreading on dynamic social networks  

NASA Astrophysics Data System (ADS)

Nowadays, information spreading on social networks has triggered an explosive attention in various disciplines. Most of previous works in this area mainly focus on discussing the effects of spreading probability or immunization strategy on static networks. However, in real systems, the peer-to-peer network structure changes constantly according to frequently social activities of users. In order to capture this dynamical property and study its impact on information spreading, in this paper, a link rewiring strategy based on the Fermi function is introduced. In the present model, the informed individuals tend to break old links and reconnect to their second-order friends with more uninformed neighbors. Simulation results on the susceptible-infected-recovered (SIR) model with fixed recovery time T=1 indicate that the information would spread more faster and broader with the proposed rewiring strategy. Extensive analyses of the information cascade size distribution show that the spreading process of the initial steps plays a very important role, that is to say, the information will spread out if it is still survival at the beginning time. The proposed model may shed some light on the in-depth understanding of information spreading on dynamical social networks.

Liu, Chuang; Zhang, Zi-Ke

2014-04-01

397

Pricing and hedging Asian basket spread options  

NASA Astrophysics Data System (ADS)

Asian options, basket options and spread options have been extensively studied in the literature. However, few papers deal with the problem of pricing general Asian basket spread options. This paper aims to fill this gap. In order to obtain prices and Greeks in a short computation time, we develop approximation formulae based on comonotonicity theory and moment matching methods. We compare their relative performances and explain how to choose the best approximation technique as a function of the Asian basket spread characteristics. We also give explicitly the Greeks for our proposed methods. In the last section we extend our results to options denominated in foreign currency.

Deelstra, Griselda; Petkovic, Alexandre; Vanmaele, Michèle

2010-04-01

398

Dynamics of interacting diseases  

E-print Network

Current modeling of infectious diseases allows for the study of complex and realistic scenarios that go from the population to the individual level of description. Most epidemic models however assume that the spreading process takes place on a single level (be it a single population, a meta-population system or a network of contacts). The latter is in part a consequence of our still limited knowledge about the interdependency of the many mechanisms and factors involved in disease spreading. In particular, interdependent contagion phenomena can only be addressed if we go beyond the scheme one pathogen-one network. In this paper, we study a model that allows describing the spreading dynamics of two concurrent diseases and apply it to a paradigmatic case of disease-disease interaction: the interaction between AIDS and Tuberculosis. Specifically, we characterize analytically the epidemic thresholds of the two diseases for different scenarios and also compute the temporal evolution characterizing the unfolding dyn...

Sanz, Joaquín; Meloni, Sandro; Moreno, Yamir

2014-01-01

399

Analysis of the spread of tuberculosis in heterogeneous complex metapopulations  

E-print Network

his paper describes and analyzes the spatial spread of tuberculosis (TB) on complex metapopulation, that is, networks of populations connected by migratory flows whose configurations are described in terms of connectivity distribution of nodes (patches) and the conditional probabilities of connections among classes of nodes sharing the same degree. The migration and transmission processes occur simultaneously. For uncorrelated networks under the assumption of standard incidence transmission, we compute the disease-free equilibrium and the basic reproduction number, and show that the disease-free equilibrium is locally asymptotically stable. Moreover, for uncorrelated networks and under assumption of simple mass action transmission, we give a necessary and sufficient conditions for the instability of the disease-free equilibrium. The existence of endemic equilibria is also discussed. Finally, the prevalence of the TB infection across the metapopulation as a function of the path connectivity is studied using nu...

Tsanou, Berge; Tewa, Jean Jules

2011-01-01

400

Epidemic cholera spreads like wildfire  

PubMed Central

Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990–2006) and former British India (1882–1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks. PMID:24424273

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

2014-01-01

401

Natural Human Mobility Patterns and Spatial Spread of Infectious Diseases  

E-print Network

We investigate a model for spatial epidemics explicitly taking into account bidirectional movements between base and destination locations on individual mobility networks. We provide a systematic analysis of generic dynamical ...

Belik, Vitaly

402

Unplanned land clearing of Colombian rainforests: Spreading like disease?  

Microsoft Academic Search

Deforestation often occurs as temporal waves and in localized fronts termed ‘deforestation hotspots’ driven by economic pulses and population pressure. Of particular concern for conservation planning are ‘biodiversity hotspots’ where high concentrations of endemic species undergo rapid loss and fragmentation of habitat. We investigate the deforestation process in Caquetá, a biodiversity hotspot and major colonization front of the Colombian Amazon

Andres Etter; Clive McAlpine; Stuart Phinn; David Pullar; Hugh Possingham

2006-01-01

403

Towards Understanding Global Spread of Disease from Everyday Interpersonal Interactions  

E-print Network

epidemic (Oc- tober 2012 - January 2013). Our model leverages the text and interpersonal interactions the simula- tions or to estimate the magnitude of these effects. By con- trast, we can now begin to model-level aggregate patterns of epidemics. By con- trast, this paper explores how individuals contribute to the global

Kautz, Henry

404

'Kissing Bug' Now Spreading Tropical Disease in U.S.  

MedlinePLUS

... also be transmitted through blood. It's a silent killer, Garcia said. People don't feel sick, so ... all three studies, published recently in the American Journal of Tropical Medicine and Hygiene , were to be ...

405

An Exactly Solvable Model for the Spread of Disease  

ERIC Educational Resources Information Center

We present a new SIR epidemiological model whose exact analytical solution can be calculated. In this model, unlike previous models, the infective population becomes zero at a finite time. Remarkably, these results can be derived from only an elementary knowledge of differential equations.

Mickens, Ronald E.

2012-01-01

406

Information spreading and development of cultural centers  

NASA Astrophysics Data System (ADS)

The historical interplay between societies is governed by many factors, including in particular the spreading of languages, religion, and other symbolic traits. Cultural development, in turn, is coupled to the emergence and maintenance of information spreading. Strong centralized cultures exist due to attention from their members, whose faithfulness in turn relies on the supply of information. Here we discuss a culture evolution model on a planar geometry that takes into account aspects of the feedback between information spreading and its maintenance. Features of the model are highlighted by comparing it to cultural spreading in ancient and medieval Europe, where it suggests in particular that long-lived centers should be located in geographically remote regions.

Dybiec, Bart?omiej; Mitarai, Namiko; Sneppen, Kim

2012-05-01

407

Epidemic spreading driven by biased random walks  

E-print Network

Random walk is one of the basic mechanisms found in many network applications. We study the epidemic spreading dynamics driven by biased random walks on complex networks. In our epidemic model, each time infected nodes constantly spread some infected packets by biased random walks to their neighbor nodes causing the infection of the susceptible nodes that receive the packets. An infected node get recovered from infection with a fixed probability. Simulation and analytical results on model and real-world networks show that the epidemic spreading becomes intense and wide with the increase of delivery capacity of infected nodes, average node degree, homogeneity of node degree distribution. Furthermore, there are corresponding optimal parameters such that the infected nodes have instantaneously the largest population, and the epidemic spreading process covers the largest part of a network.

Pu, Cunlai; Yang, Jian

2014-01-01

408

Coorelation between VHF scintillation and spread F  

NASA Astrophysics Data System (ADS)

The VHF scintillation observed over Bhopal, a station near the northern crest of the equatorial anomaly region, using the 244 MHz radio signal from FLEETSAT (730). The data use to study the occurrence characteristics of scintillation are recorded from March to April 2001 and then September to October 2001. The occurrences of scintillation are compared with the occurrence of spread-F over Delhi as observed by the modern digital ionosonde. The scintillation events are closely associated with the range type spread-F. In this paper the parameters of geomagnetic activity like Kp and Ap are used to study the association of the amplitude scintillation and spread-F. It is observed that an increase in magnetic activity suppressed the occurrence of scintillation and spread-F.

Smita, S.; Rashmi, R.; Gwal, G.

2003-04-01

409

A new theory for interface spreading  

E-print Network

A new theory for interface spreading during sedimentation of monodisperse suspensions of spheres has been developed. Employing no adjustable parameters, it compares well with new data obtained using magnetic resonance imaging....

Puthran, Hansraj Nagappa

2012-06-07

410

Epidemic spreading with information-driven vaccination  

NASA Astrophysics Data System (ADS)

Epidemic spreading has been well studied in the past decade, where the main concentration is focused on the influence of network topology but little attention is paid to the individual's crisis awareness. We here study how the crisis awareness, i.e., personal self-protection, influences the epidemic spreading by presenting a susceptible-infected-recovered model with information-driven vaccination. We introduce two parameters to quantitatively characterize the crisis awareness. One is the information creation rate ? and the other is the information sensitivity ?. We find that the epidemic spreading can be significantly suppressed in both the homogeneous and heterogeneous networks when both ? and ? are relatively large. More interesting is that the needed vaccine will be significantly reduced when the information is well spread, which is a good news for the poor countries and regions with limited resources.

Ruan, Zhongyuan; Tang, Ming; Liu, Zonghua

2012-09-01

411

Ranking the spreading influence in complex networks  

E-print Network

Identifying the node spreading influence in networks is an important task to optimally use the network structure and ensure the more efficient spreading in information. In this paper, by taking into account the shortest distance between a target node and the node set with the highest $k$-core value, we present an improved method to generate the ranking list to evaluate the node spreading influence. Comparing with the epidemic process results for four real networks and the Barab\\'{a}si-Albert network, the parameterless method could identify the node spreading influence more accurately than the ones generated by the degree $k$, closeness centrality, $k$-shell and mixed degree decomposition methods. This work would be helpful for deeply understanding the node importance of a network.

Liu, Jian-Guo; Guo, Qiang

2014-01-01

412

Modelling control of epidemics spreading by long-range interactions  

PubMed Central

We have studied the spread of epidemics characterized by a mixture of local and non-local interactions. The infection spreads on a two-dimensional lattice with the fixed nearest neighbour connections. In addition, long-range dynamical links are formed by moving agents (vectors). Vectors perform random walks, with step length distributed according to a thick-tail distribution. Two distributions are considered in this paper, an ?-stable distribution describing self-similar vector movement, yet characterized by an infinite variance and an exponential power characterized by a large but finite variance. Such long-range interactions are hard to track and make control of epidemics very difficult. We also allowed for cryptic infection, whereby an infected individual on the lattice can be infectious prior to showing any symptoms of infection or disease. To account for such cryptic spread, we considered a control strategy in which not only detected, i.e. symptomatic, individuals but also all individuals within a certain control neighbourhood are treated upon the detection of disease. We show that it is possible to eradicate the disease by using such purely local control measures, even in the presence of long-range jumps. In particular, we show that the success of local control and the choice of the optimal strategy depend in a non-trivial way on the dispersal patterns of the vectors. By characterizing these patterns using the stability index of the ?-stable distribution to change the power-law behaviour or the exponent characterizing the decay of an exponential power distribution, we show that infection can be successfully contained using relatively small control neighbourhoods for two limiting cases for long-distance dispersal and for vectors that are much more limited in their dispersal range. PMID:19126536

Dybiec, Bartlomiej; Kleczkowski, Adam; Gilligan, Christopher A.

2009-01-01

413

The Betten-Walker spread and Cayley's ruled cubic surface  

E-print Network

The Betten-Walker spread and Cayley's ruled cubic surface Hans Havlicek Rolf Riesinger Unserem) spread which is also a dual (maximal partial) spread. It is precisely the Betten-Walker spreads that allow for this construction. Every infinite Betten-Walker spread is not an algebraic set of lines

Havlicek, Hans

414

Spectral Efficiency of CDMA with Random Spreading  

Microsoft Academic Search

AbstractD The CDMA channel with randomly and indepen-dently chosen spreading sequences accurately models the sit-uation where pseudonoise sequences span many symbol peri-ods. Furthermore, its analysis provides a comparison baseline for CDMA channels with deterministic signature waveforms spanning one symbol period. We analyze the spectral efficiency (total capacity per chip) as a function of the number of users, spreading gain, and

Sergio Verdú; Shlomo Shamai

1999-01-01

415

Myosin is involved in postmitotic cell spreading  

Microsoft Academic Search

We have investigated a role for myosin in postmitotic Potoroo tridactylis kidney (PtK2) cell spreading by inhibitor studies, time-lapse video micros- copy, and immunofluorescence. We have also deter- mined the spatial organization and polarity of actin fila- ments in postmitotic spreading cells. We show that butanedione monoxime (BDM), a known inhibitor of muscle myosin II, inhibits nonmuscle myosin II and

L. P. Cramer; T. J. Mitchison

1995-01-01

416

Nonlytic viral spread enhanced by autophagy components  

PubMed Central

The cell-to-cell spread of cytoplasmic constituents such as nonenveloped viruses and aggregated proteins is usually thought to require cell lysis. However, mechanisms of unconventional secretion have been described that bypass the secretory pathway for the extracellular delivery of cytoplasmic molecules. Components of the autophagy pathway, an intracellular recycling process, have been shown to play a role in the unconventional secretion of cytoplasmic signaling proteins. Poliovirus is a lytic virus, although a few examples of apparently nonlytic spread have been documented. Real demonstration of nonlytic spread for poliovirus or any other cytoplasmic constituent thought to exit cells via unconventional secretion requires demonstration that a small amount of cell lysis in the cellular population is not responsible for the release of cytosolic material. Here, we use quantitative time-lapse microscopy to show the spread of infectious cytoplasmic material between cells in the absence of lysis. siRNA-mediated depletion of autophagy protein LC3 reduced nonlytic intercellular viral transfer. Conversely, pharmacological stimulation of the autophagy pathway caused more rapid viral spread in tissue culture and greater pathogenicity in mice. Thus, the unconventional secretion of infectious material in the absence of cell lysis is enabled by components of the autophagy pathway. It is likely that other nonenveloped viruses also use this pathway for nonlytic intercellular spread to affect pathogenesis in infected hosts. PMID:25157142

Bird, Sara Whitney; Maynard, Nathaniel D.; Covert, Markus W.; Kirkegaard, Karla

2014-01-01

417

Cytoskeleton mediated spreading dynamics of immune cells  

NASA Astrophysics Data System (ADS)

We have studied the spreading of Jurkat T-cells on anti-CD3 antibody-coated substrates as a model of immune synapse formation. Cell adhesion area versus time was measured via interference reflection contrast microscopy. We found that the spread area exhibited a sigmoidal growth as a function of time in contrast to the previously proposed universal power-law growth for spreading cells. We used high-resolution total internal reflection fluorescence microscopy of these cells transfected with GFP-actin to study cytoskeletal dynamics during the spreading process. Actin filaments spontaneously organized into a variety of structures including traveling waves, target patterns, and mobile clusters emanating from an organizing center. We quantify these dynamic structures and relate them to the spreading rates. We propose that the spreading kinetics are determined by active rearrangements of the cytoskeleton initiated by signaling events upon antibody binding by T-cell receptors. Membrane deformations induced by such wavelike organization of the cytoskeleton may be a general phenomenon that underlies cell movement and cell-substrate interactions.

Hui, King-Lam; Wayt, Jessica; Grooman, Brian; Upadhyaya, Arpita

2009-03-01

418

Spread spectrum watermarking: malicious attacks and counterattacks  

NASA Astrophysics Data System (ADS)

Most watermarking methods for images and video have been proposed are based on ideas from spread spectrum radio communications, namely additive embedding of a (signal adaptive or non-adaptive) pseudo-noise watermark pattern, and watermark recovery by correlation. Even methods that are not presented as spread spectrum methods often build on these principles. Recently, some skepticism about the robustness of spread spectrum watermarks has arisen, specifically with the general availability of watermark attack software which claim to render most watermarks undetectable. In fact, spread spectrum watermarks and watermark detectors in their simplest form are vulnerable to a variety of attacks. However, with appropriate modifications to the embedding and extraction methods, spread spectrum methods can be made much more resistant against such attacks. In this paper, we review proposed attacks on spread spectrum watermarks are systematically. Further, modifications for watermark embedding and extraction are presented to avoid and counterattack these attacks. Important ingredients are, for example, to adapt the power spectrum of the watermark to the host signal power spectrum, and to employ an intelligent watermark detector with a block-wise multi-dimensional sliding correlator, which can recover the watermark even in the presence of geometric attacks.

Hartung, Frank H.; Su, Jonathan K.; Girod, Bernd

1999-04-01

419

Peristomal Pagetoid Spread of Urothelial Carcinoma of the Ureter  

PubMed Central

Patients with ostomy including urinary stoma often develop peristomal complications, especially skin damage. The patient in this case was a 69-year old female with a history of urothelial carcinoma of the bladder and left ureter who underwent transurethral resection of a bladder tumor, nephroureterectomy and cystectomy combined with ureterocutaneostomy. Later, she had recurrence of urothelial carcinoma in the remaining ureter that spread to the peristomal epidermis, with a skin appearance resembling Paget’s disease. We report this case based on its clinical significance since we believe it is the first description of this condition in the literature. PMID:24179661

Ito, Fumio; Kihara, Ken; Shiomi, Koh; Ishizaki, Sumiko; Tanaka, Masaru; Aiba, Motohiko; Fujibayashi, Mariko; Nakazawa, Hayakazu

2013-01-01

420

Global spread of dengue virus types: mapping the 70 year history  

PubMed Central

Since the first isolation of dengue virus (DENV) in 1943, four types have been identified. Global phenomena such as urbanization and international travel are key factors in facilitating the spread of dengue. Documenting the type-specific record of DENV spread has important implications for understanding patterns in dengue hyperendemicity and disease severity as well as vaccine design and deployment strategies. Existing studies have examined the spread of DENV types at regional or local scales, or described phylogeographic relationships within a single type. Here we summarize the global distribution of confirmed instances of each DENV type from 1943 to 2013 in a series of global maps. These show the worldwide expansion of the types, the expansion of disease hyperendemicity, and the establishment of an increasingly important infectious disease of global public health significance. PMID:24468533

Messina, Jane P.; Brady, Oliver J.; Scott, Thomas W.; Zou, Chenting; Pigott, David M.; Duda, Kirsten A.; Bhatt, Samir; Katzelnick, Leah; Howes, Rosalind E.; Battle, Katherine E.; Simmons, Cameron P.; Hay, Simon I.

2014-01-01

421

Adding Taxol to Initial Chemotherapy May Be New Option When Breast Cancer Has Spread to Lymph Nodes  

Cancer.gov

Early findings from a large, multicenter trial suggest that the drug Taxol (paclitaxel), in combination with other standard chemotherapy agents, may have a small but significant benefit for breast cancer patients whose disease has spread to nearby lymph nodes.

422

The association of winds with the spread of EHDV in dairy cattle in Israel during an outbreak in 2006.  

PubMed

Winds may play a major role in spread of arthropod-borne viruses (arboviruses). Arboviruses like epizootic hemorrhagic disease virus (EHDV), bluetongue virus and bovine ephemeral fever virus (BEFV) frequently cause major outbreaks in Israel with a unique pattern of spread. Most of these outbreaks begin in the Jordan valley, near the Sea of Galilee and then spread to the north, south and west through the major valleys of Israel. The aim of this study was to describe the spread pattern in such an outbreak and to find if this pattern can be explained by winds. Herein, we compared the spread rate to each direction and used Cox proportional hazards model to test factors associated with the spread of EHDV, which emerged in diary cattle in Israel during the summer of 2006. Documented, clinical and serological data on spread of the outbreak were then compared with wind data collected by meteorological stations along the trail of virus spread and with modeled winds at high altitude (>500 m). The analysis revealed that both the hazard and the rate of outbreak spread to the south and to the north were significantly higher than to the west. Average rate of outbreak spread during periods in which at least 3 h of winds to spread direction were recorded was 20,880 m/week (SD=13,230) vs. 7486 m/week (SD=4936) in periods during which no such winds were recorded. Serological evidence demonstrated exposure to the virus up to 166 km away from the location of the initial outbreak center. Modeled wind data showed that this spread may be explained by winds at high altitudes. Animal movements due to shipments of feedlot calves and slaughters could not explain the spread pattern observed during the outbreak. This study therefore shows that winds are probably a major contributory factor for long and medium distance spread of Culicoides borne viruses in this region. PMID:20619907

Kedmi, Maor; Herziger, Yael; Galon, Nadav; Cohen, Reuma Magori; Perel, Marc; Batten, Carrie; Braverman, Yehuda; Gottlieb, Yuval; Shpigel, Nahum; Klement, Eyal

2010-09-01

423

Ethics and infectious disease.  

PubMed

Bioethics apparently suffers from a misdistribution of research resources analogous to the '10/90' divide in medical research. Though infectious disease should be recognized as a topic of primary importance for bioethics, the general topic of infectious disease has received relatively little attention from the discipline of bioethics in comparison with things like abortion, euthanasia, genetics, cloning, stem cell research, and so on. The fact that the historical and potential future consequences of infectious diseases are almost unrivalled is one reason that the topic of infectious disease warrants more attention from bioethicists. The 'Black Death' eliminated one third of the European population during the 14th Century; the 1989 flu killed between 20 and 100 million people; and, in the 20th Century smallpox killed perhaps three times more people than all the wars of that period. In the contemporary world, epidemics (AIDS, multi-drug resistant turberculosis, and newly emerging infectious diseases such as SARS) continue to have dramatic consequences. A second reason why the topic of infectious disease deserves further attention is that it raises difficult ethical questions of its own. While infected individuals can threaten the health of other individuals and society as a whole, for example, public health care measures such as surveillance, isolation, and quarantine can require the infringement of widely accepted basic human rights and liberties. An important and difficult ethical question asks how to strike a balance between the utilitarian aim of promoting public health, on the one hand, and libertarian aims of protecting privacy and freedom of movement, on the other, in contexts involving diseases that are--to varying degrees--contagious, deadly, or otherwise dangerous. Third, since their burden is most heavily shouldered by the poor (in developing countries), infectious diseases involve issues of justice--which should be a central concern of ethics. I conclude by providing sociological and historical explanations of why the topic of infectious disease has not already received more attention from bioethicists. PMID:16167406

Selgelid, Michael J

2005-06-01

424

Simulating the effect of quarantine on the spread of the 1918–19 flu in Central Canada  

Microsoft Academic Search

Quarantine is often proposed and sometimes used to control the spread of infectious diseases through a human population. Yet\\u000a there is usually little or no information on the effectiveness of attempting to quarantine humans that is not of an anecdotal\\u000a or conjectural nature. This paper describes how a compartmental model for the geographic spread of infectious diseases can\\u000a be used

Lisa Sattenspiel; D. Ann Herring

2003-01-01

425

Predictive study on the risk of malaria spreading due to global warming  

SciTech Connect

Global warming will bring about a temperature elevation, and the habitat of vectors of infectious diseases, such as malaria and dengue fever, will