Basic Reproduction Number: The expected number of new cases of an infection caused by an infected individual, in a population consisting of susceptible contacts only.Disease Transmission, Infectious: The transmission of infectious disease or pathogens. When transmission is within the same species, the mode can be horizontal or vertical (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.Epidemics: Sudden outbreaks of a disease in a country or region not previously recognized in that area, or a rapid increase in the number of new cases of a previous existing endemic disease. Epidemics can also refer to outbreaks of disease in animal or plant populations.Communicable DiseasesModels, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Influenza, Human: An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the NASAL MUCOSA; the PHARYNX; and conjunctiva, and by headache and severe, often generalized, myalgia.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Models, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Insect Vectors: Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Communicable Disease Control: Programs of surveillance designed to prevent the transmission of disease by any means from person to person or from animal to man.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.Quarantine: Restriction of freedom of movement of individuals who have been exposed to infectious or communicable disease in order to prevent its spread; a period of detention of vessels, vehicles, or travelers coming from infected or suspected places; and detention or isolation on account of suspected contagion. It includes government regulations on the detention of animals at frontiers or ports of entrance for the prevention of infectious disease, through a period of isolation before being allowed to enter a country. (From Dorland, 28th ed & Black's Veterinary Dictionary, 17th ed)Influenza A Virus, H1N1 Subtype: A subtype of INFLUENZA A VIRUS with the surface proteins hemagglutinin 1 and neuraminidase 1. The H1N1 subtype was responsible for the Spanish flu pandemic of 1918.Pandemics: Epidemics of infectious disease that have spread to many countries, often more than one continent, and usually affecting a large number of people.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Schistosoma: A genus of trematode flukes belonging to the family Schistosomatidae. There are over a dozen species. These parasites are found in man and other mammals. Snails are the intermediate hosts.Schistosoma mansoni: A species of trematode blood flukes of the family Schistosomatidae. It is common in the Nile delta. The intermediate host is the planorbid snail. This parasite causes schistosomiasis mansoni and intestinal bilharziasis.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Astronomical Processes: The behavior and interactions of matter and energy in outer space.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Principal Component Analysis: Mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components.Anisotropy: A physical property showing different values in relation to the direction in or along which the measurement is made. The physical property may be with regard to thermal or electric conductivity or light refraction. In crystallography, it describes crystals whose index of refraction varies with the direction of the incident light. It is also called acolotropy and colotropy. The opposite of anisotropy is isotropy wherein the same values characterize the object when measured along axes in all directions.History, 19th Century: Time period from 1801 through 1900 of the common era.Hemorrhagic Fevers, Viral: A group of viral diseases of diverse etiology but having many similar clinical characteristics; increased capillary permeability, leukopenia, and thrombocytopenia are common to all. Hemorrhagic fevers are characterized by sudden onset, fever, headache, generalized myalgia, backache, conjunctivitis, and severe prostration, followed by various hemorrhagic symptoms. Hemorrhagic fever with kidney involvement is HEMORRHAGIC FEVER WITH RENAL SYNDROME.Hemorrhagic Fever, Ebola: A highly fatal, acute hemorrhagic fever, clinically very similar to MARBURG VIRUS DISEASE, caused by EBOLAVIRUS, first occurring in the Sudan and adjacent northwestern (what was then) Zaire.Ebolavirus: A genus in the family FILOVIRIDAE consisting of several distinct species of Ebolavirus, each containing separate strains. These viruses cause outbreaks of a contagious, hemorrhagic disease (HEMORRHAGIC FEVER, EBOLA) in humans, usually with high mortality.Ebola Vaccines: Vaccines or candidate vaccines used to prevent EBOLA HEMORRHAGIC FEVER.Marburg Virus Disease: An RNA virus infection of rhesus, vervet, and squirrel monkeys transmissible to man.Ape Diseases: Diseases of chimpanzees, gorillas, and orangutans.PubMed: A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.Medicine in ArtPeriodicals as Topic: A publication issued at stated, more or less regular, intervals.BooksPublishing: "The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.MEDLINE: The premier bibliographic database of the NATIONAL LIBRARY OF MEDICINE. MEDLINE® (MEDLARS Online) is the primary subset of PUBMED and can be searched on NLM's Web site in PubMed or the NLM Gateway. MEDLINE references are indexed with MEDICAL SUBJECT HEADINGS (MeSH).Serial Publications: Publications in any medium issued in successive parts bearing numerical or chronological designations and intended to be continued indefinitely. (ALA Glossary of Library and Information Science, 1983, p203)ParaguayArchivesBiological Science Disciplines: All of the divisions of the natural sciences dealing with the various aspects of the phenomena of life and vital processes. The concept includes anatomy and physiology, biochemistry and biophysics, and the biology of animals, plants, and microorganisms. It should be differentiated from BIOLOGY, one of its subdivisions, concerned specifically with the origin and life processes of living organisms.Hantavirus: A genus of the family BUNYAVIRIDAE causing HANTAVIRUS INFECTIONS, first identified during the Korean war. Infection is found primarily in rodents and humans. Transmission does not appear to involve arthropods. HANTAAN VIRUS is the type species.Hantavirus Infections: Infections with viruses of the genus HANTAVIRUS. This is associated with at least four clinical syndromes: HEMORRHAGIC FEVER WITH RENAL SYNDROME caused by viruses of the Hantaan group; a milder form of HFRS caused by SEOUL VIRUS; nephropathia epidemica caused by PUUMALA VIRUS; and HANTAVIRUS PULMONARY SYNDROME caused by SIN NOMBRE VIRUS.Measles: A highly contagious infectious disease caused by MORBILLIVIRUS, common among children but also seen in the nonimmune of any age, in which the virus enters the respiratory tract via droplet nuclei and multiplies in the epithelial cells, spreading throughout the MONONUCLEAR PHAGOCYTE SYSTEM.Measles Vaccine: A live attenuated virus vaccine of chick embryo origin, used for routine immunization of children and for immunization of adolescents and adults who have not had measles or been immunized with live measles vaccine and have no serum antibodies against measles. Children are usually immunized with measles-mumps-rubella combination vaccine. (From Dorland, 28th ed)Measles virus: The type species of MORBILLIVIRUS and the cause of the highly infectious human disease MEASLES, which affects mostly children.Cross Protection: Protection conferred on a host by inoculation with one strain or component of a microorganism that prevents infection when later challenged with a similar strain. Most commonly the microorganism is a virus.Measles-Mumps-Rubella Vaccine: A combined vaccine used to prevent MEASLES; MUMPS; and RUBELLA.World Health Organization: A specialized agency of the United Nations designed as a coordinating authority on international health work; its aim is to promote the attainment of the highest possible level of health by all peoples.

Utility of R0 as a predictor of disease invasion in structured populations. (1/105)

Early theoretical work on disease invasion typically assumed large and well-mixed host populations. Many human and wildlife systems, however, have small groups with limited movement among groups. In these situations, the basic reproductive number, R0, is likely to be a poor predictor of a disease pandemic because it typically does not account for group structure and movement of individuals among groups. We extend recent work by combining the movement of hosts, transmission within groups, recovery from infection and the recruitment of new susceptibles into a stochastic model of disease in a host metapopulation. We focus on how recruitment of susceptibles affects disease invasion and how population structure can affect the frequency of superspreading events (SSEs). We show that the frequency of SSEs may decrease with the reduced movement and the group sizes due to the limited number of susceptible individuals available. Classification tree analysis of the model results illustrates the hierarchical nature of disease invasion in host metapopulations. First, the pathogen must effectively transmit within a group (R0>1), and then the pathogen must persist within a group long enough to allow for movement among the groups. Therefore, the factors affecting disease persistence--such as infectious period, group size and recruitment of new susceptibles--are as important as the local transmission rates in predicting the spread of pathogens across a metapopulation.  (+info)

Analyses of the 1957 (Asian) influenza pandemic in the United Kingdom and the impact of school closures. (2/105)

Many countries plan to close schools during a future influenza pandemic, although the potential impact is poorly understood. We apply a model of the transmission dynamics of pandemic influenza to consultation, serological and clinical data from the United Kingdom from the 1957 (Asian) influenza pandemic, to estimate the basic reproduction number (R0), the proportion of infected individuals who experience clinical symptoms and the impact of school/nursery closures. The R0 for Asian influenza was about 1.8 and 60-65% of infected individuals were estimated to have experienced clinical symptoms. During a future pandemic, closure of schools/nurseries could reduce the epidemic size only by a very small amount (<10%) if R0 is high (e.g. 2.5 or 3.5), and modest reductions, e.g. 22% might be possible if it is low (1.8) and schools are closed early, depending on assumptions about contact patterns. Further data on contact patterns and their dependence on school closures are needed.  (+info)

A mathematical model of the dynamics of Salmonella Cerro infection in a US dairy herd. (3/105)

We developed a mathematical model of the transmission dynamics of salmonella to describe an outbreak of S. Cerro infection that occurred in a Pennsylvania dairy herd. The data were collected as part of a cooperative research project between the Regional Dairy Quality Management Alliance and the Agricultural Research Service. After the initial detection of a high prevalence of S. Cerro infection in the herd, a frequent and intensive sampling was conducted and the outbreak was followed for 1 year. The data showed a persistent presence of S. Cerro with a high prevalence of infection in the herd. The dynamics of host and pathogen were modelled using a set of nonlinear differential equations. A more realistically distributed (gamma-distributed) infectious period using multiple stages of infection was considered. The basic reproduction number was calculated and relevance to the intervention strategies is discussed.  (+info)

The effect of heterogeneous infectious period and contagiousness on the dynamics of Salmonella transmission in dairy cattle. (4/105)

 (+info)

Epidemic thresholds in dynamic contact networks. (5/105)

 (+info)

Household structure and infectious disease transmission. (6/105)

 (+info)

Latent coinfection and the maintenance of strain diversity. (7/105)

 (+info)

Imported and autochthonous cases in the dynamics of dengue epidemics in Brazil. (8/105)

 (+info)

Existing estimates of the basic reproduction number, R0, for human schistosomes are mostly in the range 1-4, implying that schistosomes should be relatively easy to eliminate from endemic areas, which is contrary to practical experience. An estimate of R0 for a site in Zimbabwe is obtained here using a mathematical model explicitly incorporating two features believed to be epidemiologically significant; age-dependent exposure and acquired immunity. Parameter estimates are, as far as possible, obtained independently, but the coefficients representing man-snail and snail-man transmission, as well as parameters representing effects of acquired immunity, must be estimated indirectly by fitting the model to field data. Heterogeneity in human exposure and contamination is crudely incorporated by considering `wormy and non-wormy fractions of the population. The results suggest R0 to be in the range 4-5 or more, higher than previous estimates and despite only moderate levels of infection at this site. ...
To estimate the basic reproduction number (R(0)) of Borrelia lusitaniae and Borrelia afzelii, we formulated a mathematical model considering the interactions among the tick vector, vertebrate hosts, and pathogens in a 500-ha enclosed natural reserve on Le Cerbaie hills, Tuscany, central Italy. In the study area, Ixodes ricinus were abundant and were found infected by B. lusitaniae and B. afzelii. Lizards (Podarcis spp.) and mice (Apodemus spp.), respectively, are the reservoir hosts of these two Borrelia burgdorferi sensu lato (s.l.) genospecies and compete for immature ticks. B. lusitaniae R(0) estimation is in agreement with field observations, indicating the maintenance and diffusion of this genospecies in the study area, where lizards are abundant and highly infested by I. ricinus immature stages. In fact, B. lusitaniae shows a focal distribution in areas where the tick vector and the vertebrate reservoir coexist. Mouse population dynamics and their relatively low suitability as hosts for nymphs
We present a stochastic model for the spread of smallpox after a small number of index cases are introduced into a susceptible population. The model describes a branching process for the spread of the infection and the effects of intervention measures. We discuss scenarios in which ring vaccination of direct contacts of infected persons is sufficient to contain an epidemic. Ring vaccination can be successful if infectious cases are rapidly diagnosed. However, because of the inherent stochastic nature of epidemic outbreaks, both the size and duration of contained outbreaks are highly variable. Intervention requirements depend on the basic reproduction number R0, for which different estimates exist. When faced with the decision of whether to rely on ring vaccination, the public health community should be aware that an epidemic might take time to subside even for an eventually successful intervention strategy.
We present a dynamical model of a multi-site fishery. The fish stock is located on a discrete set of fish habitats where it is catched by the fishing fleet. We assume that fishes remain on fishing hab
This article focuses on the study of an age-structured two-strain model with super-infection. The explicit expression of basic reproduction numbers and the invasion reproduction numbers corresponding to strain one and strain two are obtained. It is shown that the infection-free steady state is globally stable if the basic reproductive number $ R_0 $ is below one. Existence of strain one and strain two exclusive equilibria is established. Conditions for local stability or instability of the exclusive equilibria of the strain one and strain two are established. Existence of coexistence equilibrium is also obtained under the condition that both invasion reproduction numbers are larger than one.
TY - JOUR. T1 - A mathematical model for the spread of Strepotococcus pneumoniae with transmission dependent on serotype. AU - Greenhalgh, David. AU - Lamb, Karen Elaine. AU - Robertson, Christopher. PY - 2012. Y1 - 2012. N2 - We examine a mathematical model for the transmission of Streptococcus Pneumoniae amongst young children when the carriage transmission coefficient depends on the serotype. Carriage means pneumococcal colonization. There are two sequence types (STs) spreading in a population each of which can be expressed as one of two serotypes. We derive the differential equation model for the carriage spread and perform an equilibrium and global stability analysis on it. A key parameter is the effective reproduction number R e. For R e ≤ 1, there is only the carriage-free equilibrium (CFE) and the carriage will die out whatever be the starting values. For R e , 1, unless the effective reproduction numbers of the two STs are equal, in addition to the CFE there are two carriage ...
Abstract: Local epidemic curves during the 1918 1919 influenza pandemic were often characterized by multiple epidemic waves. Identifying the underlying cause(s) of such waves may help manage future pandemics. We investigate the hypothesis that these waves were caused by people avoiding potentially infectious contacts a behaviour termed social distancing . We estimate the effective disease reproduction number and from it infer the maximum degree of social distancing that occurred during the course of the multiple-wave epidemic in Sydney, Australia. We estimate that, on average across the city, people reduced their infectious contact rate by as much as 38%, and that this was sufficient to explain the multiple waves of this epidemic. The basic reproduction number, R0, was estimated to be in the range of 1.6 2.0 with a preferred estimate of 1.8, in line with other recent estimates for the 1918 1919 influenza pandemic. The data are also consistent with a high proportion (more than 90%) of the ...
Abstract: Local epidemic curves during the 1918 1919 influenza pandemic were often characterized by multiple epidemic waves. Identifying the underlying cause(s) of such waves may help manage future pandemics. We investigate the hypothesis that these waves were caused by people avoiding potentially infectious contacts a behaviour termed social distancing . We estimate the effective disease reproduction number and from it infer the maximum degree of social distancing that occurred during the course of the multiple-wave epidemic in Sydney, Australia. We estimate that, on average across the city, people reduced their infectious contact rate by as much as 38%, and that this was sufficient to explain the multiple waves of this epidemic. The basic reproduction number, R0, was estimated to be in the range of 1.6 2.0 with a preferred estimate of 1.8, in line with other recent estimates for the 1918 1919 influenza pandemic. The data are also consistent with a high proportion (more than 90%) of the ...
We give a survey of results on global stability for deterministic compartmental epidemiological models. Using Lyapunov techniques we revisit a classical result, and give a simple proof. By the same methods we also give a new result on differential susceptibility and infectivity models with mass action and an arbitrary number of compartments. These models encompass the so-called differential infectivity and staged progression models. In the two cases we prove that if the basic reproduction ratio R0 \leq 1, then the disease free equilibrium is globally asymptotically stable. If R0 | 1, there exists an unique endemic equilibrium which is asymptotically stable on the positive orthant.
We propose a Bayesian statistical framework for estimating the reproduction number R early in an epidemic. This method allows for the yet-unrecorded secondary cases if the estimate is obtained before the epidemic has ended. We applied our approach to the severe acute respiratory syndrome (SARS) epidemic that started in February 2003 in Hong Kong. Temporal patterns of R estimated after 5, 10, and 20 days were similar. Ninety-five percent credible intervals narrowed when more data were available but stabilized after 10 days. Using simulation studies of SARS-like outbreaks, we have shown that the method may be used for early monitoring of the effect of control measures ...
The authors present an online tool for the data-driven inference and quantification of uncertainties for the reproduction number, as well as the time points of interventions for 51 European countries. The results quantify the rate of the diseases spread before and after interventions and provide a metric for the effectiveness of non-pharmaceutical interventions in different countries.
A striking characteristic of influenza pandemics is the multiple peaks of infection. For example, the United States has experienced two peaks of infection in each of the past four influenza pandemics, one peak during the summer months and a second peak during the typical flu season. In contrast, the number of infected individuals peaks only once during a seasonal flu. The mechanisms that cause the multiple peaks of infection during pandemic influenza seasons are not well understood. The goal of this project is to use agent-based modeling to investigate mechanisms that can generate two peaks of infection.. In this talk I will describe the susceptible-exposed-infectious-recovered (SEIR) agent-based model developed in Netlogo for simulating the 2009 H1N1 influenza pandemic. The incubation and infectiousness periods are drawn from gamma distributions. The model is calibrated by matching known average daily contacts and key epidemiological quantities, such as the basic reproduction number, the number ...
Some consequences of erroneous results concerning eigenvalues in the recent literature of mathematical biology are highlighted. Furthermore, an improved stability criterion and the true value of the basic reproduction number is presented.
Transmission-blocking interventions aim to reduce the prevalence of infection in endemic communities by targeting Plasmodium within the insect host. Although many studies have reported the successful reduction of infection in the mosquito vector, direct evidence that there is an onward reduction in infection in the vertebrate host is lacking. Here we report the first experiments using a population, transmission-based study of Plasmodium berghei in Anopheles stephensi to assess the impact of a transmission-blocking drug upon both insect and host populations over multiple transmission cycles. We demonstrate that the selected transmission-blocking intervention, which inhibits transmission from vertebrate to insect by only 32%, reduces the basic reproduction number of the parasite by 20%, and in our model system can eliminate Plasmodium from mosquito and mouse populations at low transmission intensities. These findings clearly demonstrate that use of transmission-blocking interventions alone can eliminate
We present two new visualizations, case tree plots and checkerboard plots, for visualizing emerging zoonoses.. Zoonoses represent an estimated 58% of all human infectious diseases, and 73% of emerging infectious diseases. Recent examples of zoonotic outbreaks include H1N1, SARS and Middle East Respiratory Syndrome, which have caused thousands of deaths combined. The current toolkit for visualizing data from these emerging diseases is limited.. Case tree and checkerboard plots were developed to address that gap. The visualizations are best suited for diseases like SARS for which there are a limited number of cases, with data available on human to human transmission. They a) allow for easy estimation of epidemiological parameters like basic reproduction number b) indicate the frequency of introductory events, e.g. spillovers in the case of zoonoses c) represent patterns of case attributes like patient sex both by generation and over time.. Case tree plots depict the emergence and growth of ...
Malaria infection is one of the most serious global health problems of our time. In this article the blood-stage dynamics of malaria in an infected host are studied by incorporating red blood cells, malaria parasitemia and immune effectors into a mathematical model with nonlinear bounded Michaelis-Menten-Monod functions describing how immune cells interact with infected red blood cells and merozoites. By a theoretical analysis of this model, we show that there exists a threshold value $R_0$, namely the basic reproduction number, for the malaria infection. The malaria-free equilibrium is global asymptotically stable if $R_0|1$. If $R_0|1$, there exist two kinds of infection equilibria: malaria infection equilibrium (without specific immune response) and positive equilibrium (with specific immune response). Conditions on the existence and stability of both infection equilibria are given. Moreover, it has been showed that the model can undergo Hopf bifurcation at the positive equilibrium and
Alcohol abuse is a major problem, especially among students on and around college campuses. We use the mathematical framework of [16] and study the role of environmental factors on the long term dynamics of an alcohol drinking population. Sensitivity and uncertainty analyses are carried out on the relevant functions (for example, on the drinking reproduction number and the extinction time of moderate and heavy drinking because of interventions) to understand the impact of environmental interventions on the distributions of drinkers. The reproduction number helps determine whether or not the high-risk alcohol drinking behavior will spread and become persistent in the population, whereas extinction time of high-risk drinking measures the effectiveness of control programs. We found that the reproduction number is most sensitive to social interactions, while the time to extinction of high-risk drinkers is significantly sensitive to the intervention programs that reduce initiation, and the college drop
Heterogeneity in the parameters governing the spread of infectious diseases is a common feature of real-world epidemics. It has been suggested that for pathogens with basic reproductive number R0,1, increasing heterogeneity makes extinction of disease more likely during the early rounds of transmission. The basic reproductive number R0 of the introduced pathogen may, however, be less than 1 after the introduction, and evolutionary changes are then required for R0 to increase to above 1 and the pathogen to emerge. In this paper, we consider how host heterogeneity influences the emergence of both non-evolving pathogens and those that must undergo adaptive changes to spread in the host population. In contrast to previous results, we find that heterogeneity does not always make extinction more likely and that if adaptation is required for emergence, the effect of host heterogeneity is relatively small. We discuss the application of these ideas to vaccination strategies. ...
The class of immunosuppressive lymphocytes known as regulatory T cells (Tregs) has been identified as a key component in preventing autoimmune diseases. Although Tregs have been incorporated previously in mathematical models of autoimmunity, we take a novel approach which emphasizes the importance of professional antigen presenting cells (pAPCs). We examine three possible mechanisms of Treg action (each in isolation) through ordinary differential equation (ODE) models. The immune response against a particular autoantigen is suppressed both by Tregs specific for that antigen and by Tregs of arbitrary specificities, through their action on either maturing or already mature pAPCs or on autoreactive effector T cells. In this deterministic approach, we find that qualitative long-term behaviour is predicted by the basic reproductive ratio R (0) for each system. When R (0) , 1, only the trivial equilibrium exists and is stable; when R (0)>1, this equilibrium loses its stability and a stable non-trivial ...
Abstract: We attempted to quantify the possible spread of the pandemic across a network of 52 major cities and to predict the effect of vaccination against the pandemic strain, if available. Predictions are based on simulations from a stochastic SEIR model. Parameters used in the simulations are set to values consistent with recent estimations from the outbreak in Mexico.We show that a two-wave pandemic dynamic may be observed in Southern hemisphere because of seasonal constraints for a maximum value of the basic reproductive number (R0, max) within a city equal to 1.5 and a mean generation interval (GI) of 2 days. In this case and in the absence of vaccination, attack rates may reach 46% when considering a completely susceptible population. More severe scenarios characterized by higher values of R0, max (2.2) and GI (3.1) yield an attack rate of 77%. By extrapolation, we find that mass vaccination in all countries (i.e. up to 50% of the population) implemented 6 months after the start of the ...
where t1 is the incubation period and t2 is the infectious period of the disease. The above formula assumes that infected individuals are not infectious during their incubation period (t1). Hence, we can use this formula to estimate the R0 of AHC as infected individuals become infectious once they become symptomatic. Moreover, the incubation period (t1) for AHC is small and ranges between 1 and 2 days [2] while the infectious period (t2) is estimated to range from 3 to 7 days with a mean of 5 days [1]. Hence, we estimate a reproductive number for AHC ranging between 2.7 and 5.7 with a mean of 4.1 (t1 = 1.5 days, t2 = 5 days). The estimated basic reproductive number is consistent with the rapid initial increase in the number of cases for approximately four weeks (this has been observed in other AHC outbreaks [1]). After the first four weeks of the outbreak, the number of cases decreases rapidly until the outbreak is over (Figure 1). This behavior can be attributed to the rapid depletion of ...
Newsroom America) -- Established Aedes-mosquito population could spread the Zika virus in Europe this summer if infected travelers introduce the virus. An analysis of temperatures, vectorial capacity, basic reproductive number (R0), and air traveler flows suggests parts of Southern Europe may be at risk for Zika outbreaks between June and August. This according to a study, led by Umeå University researchers in Sweden and published in the journal EBioMedicine.. "We know warm climates create the kind of conditions suitable for mosquito-borne illnesses to spread," says Joacim Rocklöv, researcher at Umeå Universitys Unit for Epidemiology and Global Health and co-author of the article.. "Vectorial capacity depends on a number of parameters but in general, warmer temperatures increase the rate in which the female mosquitos bite, the mosquito virus reproduction, and their virus transmission risk. The presence of established Aedes mosquito populations, the warmer climate and the coinciding peak flow ...
I have recently studied several models which exhibit a common phenomenon, referred to in mathematical epidemiology as a backward bifurcation, which implies that a particular phenomenon (usually an outbreak of an infectious disease) can persist in a population under certain conditions which would not normally (that is, according to its basic reproductive number R0) allow it to do so. Mathematically, this implies that there are multiple transition cycles within the population as a whole, and that although the phenomenon is not "reproducing" well within the population as a whole, it is reproducing sufficiently well within some subgroup of the population to create a "reservoir", if that subgroup begins sufficiently large. Biologically speaking, this means that these processes have a robust structure which makes them more difficult to eradicate. This complicates the control of such diseases (or other phenomena, such as eating disorders, which can be considered to be peer-pressure-driven), but also ...
In this paper, an SIS epidemic model with age of vaccination is investigated. Asymptotic smoothness of the semi-flow is proved. By analyzing the corresponding characteristic equations, the local...
R0 - the reproduction number - indicates the intensity of an outbreak. R0 is the number of cases, on average, an infected person will cause while infectious.
Fast enough for shooting in just about any type of light. Distortion-free images with superb resolution and color rendition. An ideal first lens, perfect for full-length portraits, travel photography or any type of available-light shooting. Accepts 52mm filters. Filter Size 52mm Lens Mount Nikon F-Bayonet f/Stop Range 1.4-16 Minimum Focus Distance 1.5 (0.45 m) Reproduction Ratio 0.15x (max.) Angle of View DX format: 30 30 FX format: 46 Focus Modes Auto Manual Compatible Formats FX DX FX in DX Crop Mode 35mm Film Elements/Groups 7/6 Number of Blades 7 Dimensions (Diam. x L) Approx. 2.5 x 1.7 (64.5 x 42.5mm) Weight Approx. 8.1 oz (230 g)
We propose a model of competition of nn species in a chemostat, with constant input of some species. We mainly emphasize the case that can lead to coexistence in the chemostat in a non-trivial way, i.e., where the n−1n−1 less competitive species are in the input. We prove that if the inputs satisfy a constraint, the coexistence between the species is obtained in the form of a globally asymptotically stable (GAS) positive equilibrium, while a GAS equilibrium without the dominant species is achieved if the constraint is not satisfied. This work is round up with a thorough study of all the situations that can arise when having an arbitrary number of species in the chemostat inputs; this always results in a GAS equilibrium that either does or does not encompass one of the species that is not present in the input.
President Obama and Chinas incoming president Xi Jinping should meet to revalidate and re-energize the US-China relationship. Whether this relationship is vital and robust, or weak and full of suspicion, will affect the whole world.
Containing chemical pollutants, these plastic pellets are of great danger to aquatic life. Humans need to stop harming other species. The chain of relationships among all life is linked in many ways, so it will all come back to us humans who are doing this. Learn more about these pellets here.
Estimates in the Incubation Time period and Serial Interval of MERS-CoV An infection.The empirical cumulative density perform in the observed cases (the fraction of all observations that fell beneath Just about every observed worth) (black traces) with regard for the incubation period (Panel A) and serial interval (the time in between the onset of ailment within a case affected person as well as onset of health issues in a very Make contact with) (Panel B) is revealed, having a plot from the cumulative distribution of log-typical distributions in good shape to the information indicated by thick yellow and blue lines, respectively ...
Barley and cereal yellow dwarf viruses (B/CYDV) are a suite of aphid-vectored pathogens that affect diverse host communities, including economically important crops. Coinfection of a single host by multiple strains of B/CYDV can result in elevated virulence, incidence, and transmission rates. We develop a model for a single host, two pathogen strains, and n vector species, modeled by a system of nonlinear ordinary differential equations. A single parameter describes the degree of relatedness of the strains and the amount of cross-protection between them. We compute the basic and type reproduction numbers for the model and analytically prove the (conditional) stability of the disease-free equilibrium. We demonstrate numerically that, although the basic reproduction number describes stability of the disease-free equilibrium, the type reproduction numbers better describe the individual behavior of each strain and the dynamics of coinfection. We then conduct a sensitivity analysis on the components ...
1. Mossong J, Muller CP. Estimation of the basic reproduction number of measles during an outbreak in a partially vaccinated population. Epidemiol. Infect. 2000;124:273-8 2. Edmunds WJ, Gay NJ, Kretzschmar M, Pebody RG, Wachmann H. The pre-vaccination epidemiology of measles, mumps and rubella in Europe: implications from modelling studies. Epidemiol Infect. 2001;125:635-50 3. Whitaker HJ, Farrington CP. Estimation of infectious disease parameters from serological survey data: the impact of regular epidemics. Stat. Med. 2004;23:2429-43 4. Wallinga J, Levy-Bruhl D, Gay NJ, Wachmann CH. Estimation of measles reproduction ratios and prospects for elimination of measles by vaccination in some Western European countries. Epidemiol. Infect. 2001;127:281-95 5. Willias BG, Cutts FT, Dye C. Measles vaccination policy. Epidemiol. Infect. 1995;115:603-21 6. Orenstein WA, Bernier RH, Hinman AR. Assessing vaccine efficacy in the field. Epidemiol. Rev. 1988;10:212-41 7. Farrington CP, Kanaan MN, Gay NJ. ...
The status of measles elimination is best summarized by evaluation of the effective reproduction number R; maintaining R,1 is necessary and sufficient to achieve elimination. Previously described methods for estimating R from the sizes and durations of chains of measles transmission and the proportion of cases imported were applied to the measles data reported for the United States in 1997-1999. These comprised 338 cases, forming 165 chains of transmission, of which 43 had ,1 case. One hundred seven cases were classified as importations. All 3 methods suggested that R was in the range 0.6-0.7. Results were not sensitive to the minimum size and duration of outbreak considered (so long as single-case chains were excluded) or to exclusion of chains without a known imported source. These results demonstrate that susceptibility to measles was beneath the epidemic threshold and that endemic transmission was eliminated.. ...
Stochastic computer simulations were used for quantifying the effect of selecting on prion protein (PrP) genotype on the risk of major outbreaks of classical scrapie and the rate of genetic progress in performance in commercial sheep populations already undergoing selection on performance. The risk of a major outbreak on a flock was measured by the basic reproduction ratio (R0). The effectiveness of different PrP selection strategies for reducing the population risk was assessed by the percentage of flocks with R0 , 1. When compared with the scenario where there was no selection on PrP genotype, selection against the VRQ allele had a minimal impact on genetic progress for performance traits. However, this strategy was not sufficient to eliminate the population risk after 15 years of selection when the initial frequency of the ARR allele was relatively low. More extreme PrP selection strategies aimed at increasing the frequency of the ARR allele and decreasing the frequency of the VRQ allele led ...
A delayed predator-prey system with Holling type II functional response and stage structure for both the predator and the prey is investigated. By analyzing the corresponding characteristic equations, the local stability of each of the feasible equilibria of the system is addressed and the existence of a Hopf bifurcation at the coexistence equilibrium is established. By means of persistence theory on infinite dimensional systems, it is proved that the system is permanent. By using Lyapunov functions and the LaSalle invariant principle, the global stability of each of the feasible equilibria of the model is discussed. Numerical simulations are carried out to illustrate the main theoretical results.
The overall aim of this review was to assemble the evidence that will help unravel the genetic components underlying differences in response to TB. Research in livestock host variability in response to BTB could deliver genetic markers such as SNPs associated with resistance. Implementation could be by the use of genetic markers associated with TB resistance/susceptibility in existing breeding programmes or even the identification of genetically susceptible sires to avoid their use in high BTB prevalence regions. The latter approach could help to achieve the goal set by Cox et al. (2005) who argued that even modest reduction in the reproduction number of M. bovis in cattle could bring the current epidemic under control.. It is possible that M. bovis and cattle may have reached an evolutionary stalemate, as has been proposed for humans (Muse Davis & Ramakrishnan 2009). While this proposed tolerance of host for pathogen and pathogen for host may well be an example of coevolution to maximize the ...
Chassis number R4 is the ex-Jim Clark Team Lotus racing car which he used during most of the 1963 F1 season. Jim Clark scored 7 Grand Prix victories and won...
If its a stripe set Im fairly sure youll get 4 * the smallest drive. For maximum space, although without the performance gain of striping, you could make a volume set which just adds the capacities together. Data is written to drive 1 until it becomes full, then drive 2 etc. Performance isnt as good as striping but you can dynamically extend the set with extra drives whenever you like. -----Original Message----- From: Sorin Srbu [mailto:[email protected]] Sent: 07 September 2004 11:59 To: Windows2000 Mailing List Subject: [windows2000] Slightly OT: Software RAID with win2k/xp pro Hi all, Im fiddling with a raid test over here, with some really ancient hardware. Basics: * 4x harddrives; 428M, 421M, 540M and 540M respectively. * Win2k pro sp4 Question: If I make them all dynamic disks, and build a simple stripe set (non-redundant = RAID 0?), will all the space be accumulated to a single big array (428M + 421M + 540M +540M = 1929M), or will the smallest drive decide the final size (4 x ...
In a world shaken by terrorism, the Syrian war and the migrant influx in Europe, reducing poverty is increasingly vital to achieving global stability, says Dana Hyde, head of the Millennium Challenge Corp. VOAs Miriama Diallo speaks with her about the independent U.S. aid organizations mission.
We calculated empirical cumulative density capabilities on the incubation period of time and serial intervals by computing the cumulative portion of all observations that fell under Just about every observed price from the respective knowledge sets. We estimated the incubation period by determining the earliest and most recent time of feasible exposure and time of symptom onset for every case ...
The model estimated that an 80% reduction in domestic HCV incidence was achievable by 2030, 2025 or 2020 if a minimum of 55/1,000, 75/1,000 and 188/1,000 PWID were treated per year, respectively (a total of 22, 30 and 75 of the estimated 400 PWID in Iceland per year, respectively). Regardless of time frame, this required an increased number of PWID to be diagnosed to generate enough treatment demand, or a 20% scale-up of harm reduction services to complement treatment-as-prevention incidence reductions. When DAA scale-up was combined with annual antibody testing of PWID, the incidence reduction target was reached by 2024. Treatment scale-up with no other changes to current testing and harm reduction services reduced the basic reproduction number of HCV from 1.08 to 0.59, indicating that future outbreaks would be unlikely.. ...
Usutu virus (USUV) is a mosquito-borne flavivirus, reported in many countries of Africa and Europe, with an increasing spatial distribution and host range. Recent outbreaks leading to regional declines of European common blackbird (Turdus merula) populations and a rising number of human cases emphasize the need for increased awareness and spatial risk assessment. Modelling approaches in ecology and epidemiology differ substantially in their algorithms, potentially resulting in diverging model outputs. Therefore, we implemented a parallel approach incorporating two commonly applied modelling techniques: (1) Maxent, a correlation-based environmental niche model and (2) a mechanistic epidemiological susceptible-exposed-infected-removed (SEIR) model. Across Europe, surveillance data of USUV-positive birds from 2003 to 2016 was acquired to train the environmental niche model and to serve as test cases for the SEIR model. The SEIR model is mainly driven by daily mean temperature and calculates the basic
An SIR epidemiological community-structured model is constructed to investigate the effects of clustered distributions of unvaccinated individuals and the distribution of the primary case relative to
Why and how do some parasites persist in a host population while others fail to? Why and how does the same parasite successfully invade one population while it rapidly becomes extinct in another population of the same species? Central to almost all theoretical studies on the persistence of infectious diseases is the reproductive number R0, a threshold defined as the expected number of infections produced by a single infected host in a fully susceptible host population. It is generally admitted that disease extinction (without host population extinction) occurs only if R0,1 (Anderson & May 1986, 1991; Diekmann & Heesterbeek 2000). But R0 is derived from deterministic models which assume that the host population size is large enough to neglect stochastic fluctuations. This assumption must be relaxed when the total population size or the number of infected hosts is small (e.g. in the early phases of disease invasion; Nasell 2002; Cross et al. 2007). In opposition to the classical R0 argument, ...
With p being by itself on the left side of the equation, it can now be written as pc to represent the critical proportion of the population needed to become immune to stop the transmission of disease, or the herd immunity threshold.[9] R0 functions as a measure of contagiousness, so low R0 values are associated with lower HITs, whereas higher R0s result in higher HITs.[30][43] For example, the HIT for a disease with an R0 of 2 theoretically is only 50%, whereas with disease with an R0 of 10 the HIT is 90%.[30] These calculations assume that the entire population is susceptible, meaning no individuals are immune to the disease. In reality, varying proportions of the population are immune to any given disease at any given time.[9] To account for this, the effective reproductive number Re, also written as Rt, or the average number of infections caused at time t, can found by multiplying R0 by the fraction of the population that is still susceptible. When Re is reduced to and sustained below 1, the ...
Chapter R Review R.1 Real Numbers R.2 Algebra Review R.3 Geometry Review R.4 Polynomials R.5 Factoring Polynomials R.6 Synthetic Division R.7 Rational Expressions R.8 nth Roots; Rational Exponents Chapter 1 Graphs, Equations, and Inequalities 1.1 Rectangular Coordinates; Graphing Utilities; Introduction to Graphing Equations 1.2 Solving Equations Using Graphing Utility; Linear and Rational Equations 1.3 Solving Quadratic Equations 1.4 Complex Numbers; Quadratic Equations in the Complex Number System 1.5 Radical Equations; Equations Quadratic in Form; Absolute Value Equations; Factorable Equations 1.6 Problem Solving: Interest, Mixture, Uniform Motion, Constant Rate Jobs 1.7 Solving Inequalities 1.8 Lines 1.9 Circles Chapter Review Chapter Test Chapter Project Chapter 2 Functions and Their Graphs 2.1 Intercepts and Symmetry; Graphing Key Equations 2.2 Functions 2.3 The Graph of a Function 2.4 Properties of Functions 2.5 Linear Functions and Models 2.6 Library of Functions; Piecewise-Defined ...
Learning Math: Data Analysis, Statistics, and Probability is a production of WGBH Interactive and WGBH Educational Programming and Outreach for Annenberg Media.. Copyright © 2002 WGBH Educational Foundation. All rights reserved.. The contents of this module were developed in part under a grant to PBS from the Department of Education, Award Number R286A950001-99. However, the contents do not necessarily represent the policy of the Department of Education, and you should not assume endorsement by the Federal Government.. Senior Producer ...
Superior Court Judge Julia L. Aurigemma has granted class certification in a case in which more than 100 Pratt & Whitney employees say they were caught in a squeeze between the company and a labor union. Pratt told the salaried workers in 1992 and 1993 to choose between being laid off or going back to the clock by being demoted to hourly positions. The workers filed the complaint in 1994. The total amount of damages could be between $1 million and $2 million depending on the final size of the class.
For instance, in Figure 2, if we suppose there are 40 susceptible people in cell \(C_{1010}\) located at the lower right corner of Ω, and 50 in each of the other cells, we can see that at instant \(i=150\), the number \(S^{C_{1010}}\) becomes less important and takes a value close/or equal to 20, while \(S^{C_{pq}}\) in the cells of \(V_{1010}\) takes values close/or equal to 30. As we move away from \(V_{1010}=\{C_{109},C_{910},C _{99}\}\), \(S^{C_{pq}}\) remains important. At instant \(i=300\), we can observe that in most of cells \(S^{C_{pq}}\) becomes less important, taking values between 0 and 10, while in other cells it takes values between 20 and 40 except \(S^{C_{1010}}\) which conserves its value in 50 since it is located far away from the source of infection. At instant \(i=450\), \(S^{C_{pq}}\) becomes zero except at the corners and in most cells at the borders of Ω, because these cells have vicinity sets smaller than other cells. Finally, at last instants, \(S^{C_{pq}}\) converges ...
A course on how to simulation human movement with an emphasis on using Opensim. The course materials can be downloaded from the Documents section.
During this time of school closure, please provide us with information about your level of access to technology from home so that we can provide you with the resources needed to continue your education remotely. We appreciate a separate form for each student in grades 9- ...
These scenario projections were modeled using a serial interval of 14 days, a basic reproductive number of 15, and an MMR vaccination effectiveness rate of 95%. Effective reproductive number was calculated using these three initial parameters under 5 different vaccination scenarios. Projected incidence was modeled via the IDEA (Incidence Decay and Exponential Adjustment) method; the decay factor was estimated using real data from the ongoing 2015 Disneyland measles outbreak. ...
The reproductive ratio, R0, is defined as the expected number of secondary infections of an initial infectious individual in a completely susceptible host population, and is related to the likelihood and extent of an epidemic (Anderson & May 1991). The epidemic threshold is a critical value of R0, at which epidemics become possible. This value has been shown to depend on the transmission and recovery rates of a disease, as well as the structure of the host population through which it spreads (Diekmann & Heesterbeek 2000; Serrano & Boguńá 2006; Trapman 2007). A primary goal of public health is to bring diseases under their epidemic thresholds by lowering transmission rates, increasing recovery rates, disrupting contacts that can lead to disease transmission, or immunizing susceptible hosts (Meyers et al. 2005).. For most diseases, field epidemiologists go to great lengths to estimate R0; and mathematical epidemiologists often derive results of their models in terms of R0. This value thus serves ...
Lahrouz, A. and Omari, L. (2013) Extinction and stationary distribution of a stochastic SIRS epidemic model with non-linear incidence. Statistics & Probability Letters, 83, 960-968.
View Notes - andersson from MATH 101 at Uni Saarland. STOCHASTIC EPIDEMIC MODELS AND THEIR STATISTICAL ANALYSIS Hakan ANDERSSON and Tom BRITTON February 2000 Hakan Andersson Group Financial Risk
A Reduce and Replace Strategy for Suppressing Vector-Borne Diseases: Insights from a Deterministic Model. . Download books free in pdf. Online library with books, university works and thousands of documents available to read online and download.
TY - JOUR. T1 - Epidemics in Competition. T2 - Partial Cross-Immunity. AU - Andreasen, Viggo. PY - 2018. Y1 - 2018. N2 - The competition between two pathogen strains during the course of an epidemic represents a fundamental step in the early evolution of emerging diseases as well as in the antigenic drift process of influenza. The outcome of the competition, however, depends not only on the epidemic properties of the two strains but also on the timing and size of the introduction, characteristics that are poorly captured by deterministic mean-field epidemic models. We describe those aspects of the competition that can be determined from the mean-field models giving the range of possible final sizes of susceptible hosts and cumulated attack rates that could be observed after an epidemic with two cross-reacting strains. In the limit where the size of the initial infection goes to zero, the possible outcomes lie on a (one dimensional) curve in the outcome space.. AB - The competition between two ...
From a biological perspective, a dynamic model describing the cultivation and flocculation of a microorganism that uses two different kinds of nutrients (carbon source and nitrogen source) is proposed. For the proposed model, there always exists a boundary equilibrium, i.e., R h o d o p s e u d o m o n a s p a l u s t r i s -free equilibrium. Furthermore, under additional conditions, the model also has five positive equilibria at most, i.e., the equilibria for which carbon source, nitrogen source, R h o d o p s e u d o m o n a s p a l u s t r i s and flocculants are coexistent. The phenomena of backward and forward bifurcations are extensively discussed by using center manifold theory. The global stability of the boundary equilibrium of the proposed model is deeply investigated. Moreover, the local stability of the positive equilibrium and the uniform persistence of the proposed model are discussed. Under additional conditions, the global stability of the positive equilibrium is
In this study, we have investigated the effects of partial PP coverage and found that under some circumstances, it is plausible that partial coverage with popular PP techniques used today, such as ITN, bednets and repellents, can lead to substantial increases in the reproductive number, R0. This result is similar to the diversity amplification effect which occurs due to vector preference towards specific host species in a two-species community [20]. In both cases, an increase in R0 occurs when vectors divert from one host group (TG or less preferred host species) to the other (the UTG or the preferred host species).. Previous models have pointed out the potential negative effects that partial bednet coverage can have due to diversion of vectors from the TG to the UTG, when combined with low killing efficiency [11,21,34]. The effects estimated, however, were very low, particularly at the level of the entire population [11,31,32]. It has also been speculated that total population morbidity could ...
Vorrätiges Filmmaterial Many school closures could affect pupils who are taking exams which are due to start on monday. Sarah CAMPBELL rep.
Guid: NNAL203K
Story Number: 008/10/PASB01/02
Videoklipp med Many school closures could affect pupils who are taking exams which are due to start on monday. Sarah CAMPBELL rep.
Guid: NNAL473B
Story Number: 008/10/PASB06/02
Harvesting Energy from Human Movement - Harvesting energy from human movement can be accomplished with piezoelectric flooring. Learn about harvesting energy from human movement.
Electronic files of the final versions of both the text and illustrations should be provided when the paper has been accepted for publication. You will be asked to upload them to ScholarOne Manuscripts, via the journal´s website. Files should be named using the paper number and appropriate identifying information (e.g. IS05001_Fig1). The text and figure captions should be sent as a single Word file, and the tables as separate Word files. If you are unable to supply files in Word, please contact the Editor-in-Chief for acceptable alternatives.. Line drawings should be scanned at high resolution, at least 800 dpi at final (printed) size, and saved in black and white bitmap format as TIFF files. Fine line drawings with a lot of variable grey shading should be saved in greyscale format as TIFF files. Photographs should be scanned at a resolution of at least 300 dpi at final size and saved in greyscale format as TIFF or Photoshop files. It is preferable for labels to be applied electronically to the ...
Unscramble reproduction, Unscramble letters reproduction, Point value for reproduction, Word Decoder for reproduction, Word generator using the letters reproduction, Word Solver reproduction, Possible Scrabble words with reproduction, Anagram of reproduction
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Centers RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.. ...
Evolutionary Methods for Analysis of Human Movement: 10.4018/978-1-59140-836-9.ch010: A movement rehabilitation therapist must first diagnose the cause of disability and then prescribe therapies that specifically target the dysfunctional unit
With nationwide school closures in effect, many parents are now monitoring homeschooling while at the same time trying to make a living in the midst of an
The quantitative role of sheep in the transmission of foot-and-mouth disease virus (FMDV) is not well known. To estimate the role of sheep in the transmission of FMDV, a direct contact transmission experiment with 10 groups of animals each consisting of 2 infected lambs and 1 contact calf was performed. Secretions and excretions (oral swabs, blood, urine, faeces and probang samples) from all animals were tested for the presence of FMDV by virus isolation (VI) and/or RT-PCR. Serum was tested for the presence of antibodies against FMDV. To estimate FMDV transmission, the VI, RT-PCR and serology results were used. The partial reproduction ratio R0p i.e. the average number of new infections caused by one infected sheep introduced into a population of susceptible cattle, was estimated using either data of the whole infection chain of the experimental epidemics (the transient state method) or the final sizes of the experimental epidemics (the final size method). Using the transient state method, R0p was
Extrinsic and environmental factors are known to affect the transmission of arthropod-borne viruses (arboviruses), including variations in the arthropod vector populations. Differences among these factors have been associated with differential transmission and are sometimes used to control the spread of an arbovirus through a vertebrate population in an effort to prevent or disrupt an outbreak. However, diversity in intrinsic viral populations, such as genetic and phenotypic variability, is not often accounted for when considering alterations in transmission. Presented in this dissertation are four experimental studies that explore the contribution of viral intrinsic factors, especially phenotypic variability, to the transmission potential of arboviruses as judged by modeling parameters such as vectorial capacity (VC) and the basic reproductive number (R0). The overall hypothesis of this research is that phenotypic differences of arboviruses alter the transmission potential of these arboviruses by
Background: The Ebola virus (EBOV) epidemic in Western Africa is the largest in recorded history and control efforts have so far failed to stem the rapid growth in the number of infections. Mathematical models serve a key role in estimating epidemic growth rates and the reproduction number (R0) from surveillance data and, recently, molecular sequence data. Phylodynamic analysis of existing EBOV time-stamped sequence data may provide independent estimates of the unobserved number of infections, reveal recent epidemiological history, and provide insight into selective pressures acting upon viral genes.. Methods: We fit a series mathematical models of infectious disease dynamics to phylogenies estimated from 78 whole EBOV genomes collected from distinct patients in May and June of 2014 in Sierra Leone, and perform evolutionary analysis on these genomes combined with closely related EBOV genomes from previous outbreaks. Two analyses are conducted with values of the latent period that have been used ...
In Costa Rica, the first known cases of Zika were reported in 2016. We looked at the 2016-2017 Zika outbreak and explored the transmission dynamics using weekly reported data. A nonlinear differential equation single-outbreak model with sexual transmission, as well as host availability for vector-feeding was used to estimate key parameters, fit the data and compute the |em|basic reproductive number|/em|, |em|R|/em|₀, distribution. Furthermore, a sensitivity and elasticity analysis was computed based on the |em|R|/em|₀ parameters.
Cerebral infarction is the most common form of stroke (80% of strokes). Stroke is the first cause of acquired disability, and the 2nd cause of dementia and death. The only approved treatment in the first 4.5 hour is intravenous rt-PA thrombolysis (Actilyse ®) whose objective is recanalization of occluded artery and reperfusion of the brain parenchyma. Few patients are treated (1-5%) and they keep disability in 50-60% of cases. This handicap is mainly correlated to the final infarct size. The objective of neuroprotective treatments is to reduce the final size of the cerebral infarction. The per-conditioning remote ischemic (Per-CID) showed a neuroprotective effect in cerebral ischemia by reducing the final size of cerebral infarction animal models. The per-CID corresponds, in cases of cerebral ischemia, to iterative ischemia realization of a member with a cuff. In humans, the per-CID has shown a cardioprotective effect in a randomized control trial involving 250 patients within 6 first hours of ...
The 1918 Spanish flu killed up to 40 million people. The swine flu pandemic in 2009 killed an estimated 284,000. Now, scientists have discovered a substance that could help doctors save lives during future influenza pandemics.
Funded in part by by the National Center for Research Resources and the Office of Research Infrastructure Programs (ORIP) of the National Institutes of Health through Grant Number R25 OD011097 and by an undergraduate science education award from the Howard Hughes Medical Institute. National Institutes of ...
Funded in part by by the National Center for Research Resources and the Office of Research Infrastructure Programs (ORIP) of the National Institutes of Health through Grant Number R25 OD011097 and by an undergraduate science education award from the Howard Hughes Medical Institute. National Institutes of ...
2014 Amendment to Schedules-GN R352-GG37622. 2014 Extract Section 22A(8) and(9)-Act 101-1965. PHENYLBUTAZONE RESCHEDULED AND DECLARED A PROHIBITED SUBSTANCE!. Phenylbutazone has been rescheduled as a Schedule 7 substance (previously a Schedule 6 medicine) and consequently declared a prohibited substance, effective as from 8 May 2014, the date of publication of the Amendment to the Schedules (including Schedule 7) published in terms of section 22A of Act 101 of 1965 in Government Gazette Number 37622 under Notice Number R352. The amendments, including the rescheduling, came into operation on the date of publication of the Government Gazette.. The amendment notice (attached) must be read in conjunction with Section 22A(8) & (9) of Act 101 of 1965. An extract of the relevant subclauses of Section 22 is attached and the relevant parts highlighted. The meaning of both documents read in conjunction, in short means that NO PERSON may acquire, use, possess, manufacture or supply any Schedule 7 substance ...
2014 Amendment to Schedules-GN R352-GG37622. 2014 Extract Section 22A(8) and(9)-Act 101-1965. PHENYLBUTAZONE RESCHEDULED AND DECLARED A PROHIBITED SUBSTANCE!. Phenylbutazone has been rescheduled as a Schedule 7 substance (previously a Schedule 6 medicine) and consequently declared a prohibited substance, effective as from 8 May 2014, the date of publication of the Amendment to the Schedules (including Schedule 7) published in terms of section 22A of Act 101 of 1965 in Government Gazette Number 37622 under Notice Number R352. The amendments, including the rescheduling, came into operation on the date of publication of the Government Gazette.. The amendment notice (attached) must be read in conjunction with Section 22A(8) & (9) of Act 101 of 1965. An extract of the relevant subclauses of Section 22 is attached and the relevant parts highlighted. The meaning of both documents read in conjunction, in short means that NO PERSON may acquire, use, possess, manufacture or supply any Schedule 7 substance ...
The mechanisms by which organs control cell proliferation to reach an appropriate final size during development and regeneration are a central question of biolo...
A SCHOOL will close for the end of the year early after an outbreak of whooping cough was confirmed by the region's health authorities.
The district has created a comprehensive closure plan that contains information on all aspects of our operations during this closure. On this site, you will find information on enrichment opportunities, student and teacher expectations, parent and family resources, frequently asked questions, and food services information. ...
After two years of providing fresh ideas and cooking techniques in the form of online classes, the Taste of Home Online Cooking School closed on November 30, 2017. Were proud of how much you enjoyed our helpful videos and tips, and although its sad to say goodbye, were eager to direct our efforts toward new […]
Transmission dynamics of primary pneumonic plague in the USA - Volume 140 Issue 3 - A. F. HINCKLEY, B. J. BIGGERSTAFF, K. S. GRIFFITH, P. S. MEAD
May 18th, 11:30 AM May 18th, 12:00 PM Mathematical Modeling for the Transmission Dynamics of {\it Mycobacterium marinum} Incorporating Intra-host Variability. ALC 1102. ...
reproduction: Process by which organisms replicate themselves. In a general sense reproduction is one of the most important concepts in biology: it means making a copy, a likeness, and thereby...
CRRA, Centre de recherche en reproduction animale. Situé à la faculté de médecine vétérinaire de luniversité de Montréal à St-haycinthe.
If you are to pay the Dotnode Project, roughly know clinically-tested to guarantee any ebook immunological aspects of mammalian reproduction. Regulation completely to know out more. Please, speed were mbHealth.
Urinary diversion or urostomy is a condition usually related to a bladder cancer surgical treatment. The management of this artificial orifice needs some advice and information.
Abstract. In sub-Saharan Africa, little is known about the epidemiology of pandemic-prone influenza viruses in urban settings. Using data from a prospective sentinel surveillance network, we characterized the emergence, epidemiology, and transmission dynamics of 2009 pandemic A/H1N1 influenza (H1N1pdm09) in Kampala, Uganda. After virus introduction via international air travel from England in June 2009, we estimated the basic reproductive number in Kampala to be 1.06-1.13, corresponding to attack rates of 12-22%. We subsequently identified 613 cases of influenza in Kampala from 2009 to 2015, of which 191 (31.2%) were infected with H1N1pdm09. Patients infected with H1N1pdm09 were more likely to be older adult (ages 35-64) males with illness onset during rainy season months. Urban settings in sub-Saharan Africa are vulnerable to importation and intense transmission of pandemic-prone influenza viruses. Enhanced surveillance and influenza pandemic preparedness in these settings is needed.
How many people need to be vaccinated to achieve herd immunity varies from disease to disease.. Measles can be transmitted through coughing and sneezing and the virus causing measles can survive outside the body for up to two hours. So its possible to catch measles just by being in the same room as someone who is ill if you touch a surface theyve coughed or sneezed on.. In contrast, Ebola can only be spread by direct contact with infected secretions (blood, faeces or vomit) and therefore requires close contact with an ill person. This makes it much less spreadable.. We can determine how contagious a disease is by tracking its spread throughout a population. In doing so, we can attribute each disease a reproductive number denoted by the symbol Ro. The bigger the Ro the more easily the disease is spread throughout the population.. If everyone who has a disease on average infects two people, the Ro for that disease is 2. This means the disease, relatively speaking, is not particularly contagious. ...
The QMRA Wiki is supported by Michigan State University and Ohio State University through support by the National Institute of General Medical Sciences of the National Institutes of Health Number R25GM108593 and the Homer Nowlin Chair in Water Research. The content is solely the responsibility under Award of the authors and does not necessarily represent the official views of the National Institutes of Health.. ...
For submitting manuscripts that have made use of services or resources from this core, PLEASE ACKNOWLDGE SUPPORT by inclusion of the following information:. "This work was supported by the GT3 Core Facility of the Salk Institute with funding from NIH-NCI CCSG: P30 014195, an NINDS R24 Core Grant and funding from NEI" Please acknowledge core staff where appropriate and consider authorship inclusion when scientific contributions merit.. Please link each publication stemming from work performed in the core to your MyNCBI account. This will ensure that the contributions from NIH are appropriately acknowledged in renewal and continuation applications. This NIH requirement must be satisfied as part of our efforts to provide consistent access to stabling funded core resources. Information on how to link publications can be found here». Research reported was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under Award Number R24NS092943. The ...
Start Date of Comment Period 01/11/2010 End Date of Comment Period 02/24/2010 Start Date of Notice Period 01/01/2011 Revision History Number R8 Revision History Explanation R8 (effective RULES OF CONDUCT You agree that you will not, directly or indirectly, perform or assist in any of the following actions as they relate to the Website or Services: Engage in NEITHER TCI NOR ANY PROVIDER OF THIRD PARTY CONTENT OR THEIR RESPECTIVE AGENTS WARRANTS THAT THE SERVICE WILL BE UNINTERRUPTED OR ERROR-FREE; NOR DOES TCI, ANY THIRD PARTY CONTENT PROVIDER, OR Typically, these timeframes are either 10 or 90 days for "minor surgical procedures", of which debridements are included. It is expected that, with appropriate care, and no extenuating medical or surgical complications or setbacks, wound volume or surface dimension should decrease over time. The wound of right leg is 15 sq cm and debrided to muscle. This may include, for example, evaluation of pulses, ABI and/or possible consultation with a vascular ...
Internet Numbers RFC 997 Network Numbers R 192.012.024.rrr MICANET MITRE (Experimental) [WDL] R 192.012.025.rrr CSS-GRAMINAE CSS Workstation Net [16,RR2] R 192.012.026.rrr NOSC-NETR Net-R Testbed at BBN [26,CP10] R 192.012.027.rrr UR-LASER UR Laser Energetics [30,WXL] R*192.012.028.rrr RIACS-X-NET RIACS-Experimental-Net [DG28] D 192.012.029.rrr RF-EVANS ADDCOMPE DC3 LAN1 [30,MB31] D 192.012.030.rrr RF-HEX-A ADDCOMPE DC3 LAN2 [30,MB31] D 192.012.031.rrr USNA-ENET USNA Engineering Net [30,TS9] R*192.012.032.rrr CMU-VINEYARD CMU File Cluster Net [30,MXK] R 192.012.033.rrr SRI-CSL-NET SRI-CSL 10MB Ethernet [GEOF] C*192.012.034.rrr-192.012.043.rrr Schlumberger PA Net [30,RXB] R 192.012.044.rrr T NRTC-NET Northrop Research Net [30,RSM1] R 192.012.045.rrr ACC-SB-IMP-NET ACC Santa Barbara IMP [AB20] R 192.012.046.rrr ACC-SB-ETHER ACC Santa Barbara Ethernet[AB20] R 192.012.047.rrr UMN-UCC-NET Univ. of Minnesota [RG12] G 192.012.048.rrr AMES-ED-EXPNET Code ED Exp. Net. [30,MSM1] G 192.012.049.rrr ...
not shown in the ChimeraX browser; copy link to a standard browser to view): flypore.mp4 Movie duration. The movie is 2000 frames at 90 frames per second, for a running time of 22 seconds. It is encoded in H.264 format, and the file size of 27 Mbytes gives a data rate of about 100 Mbytes/minute or 6 Gbytes/hour; however, compression is better than usual because the motion in the movie is very slow. The disk space used by the uncompressed (ppm format) image frames before the movie was encoded was about 33 Gbytes, about 1000x the final size - recording a long movie requires a lot of disk space. Rendering the movie took about 15 minutes, or 30x slower than real time. Eye separation / physical scale. In recording a stereoscopic (two-eye) movie, it is important to choose an appropriate eye separation in the units of the scene, typically Å. This controls how large and nearby the models will appear in the headset. For the nuclear pore, which is 1000 Å in diameter with a channel diameter of about 500 ...
Also Environmental Studies 21.) A study of the relationships of plants and animals (including humans) to each other and to their environment. Well start by considering the decisions an individual makes in its daily life concerning its use of resources, such as what to eat and where to live, and whether to defend such resources. Well then move on to populations of individuals, and investigate species population growth, limits to population growth, and why some species are so successful as to become pests whereas others are on the road to extinction. The next level will address communities, and how interactions among populations, such as competition, predation, parasitism, and mutualism, affect the organization and diversity of species within communities. The final stage of the course will focus on ecosytems, and the effects of humans and other organisms on population, community, and global stability. Three hours of lecture per week. Requisite: Biology 18 or Enviornmental Studies 12 or ...
Schools in the Washington metropolitan region announced closures for Tuesday afternoon in anticipation of the first snowfall of the year.
We have derived a broad, deterministic model of the steady-state actin cycle that includes its major regulatory mechanisms. Ours is the first model to solve the complete nucleotide profile within filaments, a feature that ...
Due the circumstances surrounding the Coronavirus, the College has established guidelines for students and teachers in the event of school closure. The following information is an outline of what the community needs to know if the school were to close. All pertinent information will be emailed to parents directly. This information has been provided so that you are able to make adequate arrangements ahead of time. ...
A new paper in The Lancet Infectious Diseases describes a mathematical method for estimating the fitness of antiviral-resistant (AVR) flu strains that the authors say can be easily integrated into surveillance systems.. In the paper, US researchers defined the fitness of AVR strains as their reproductive number relative to their co-circulating antiviral-susceptible (AVS) flu strains and developed a simple method for real-time estimation of AVR fitness from surveillance data. The method requires only information on generation time, without other specific details regarding transmission dynamics. The experts then applied this method to two retrospective case studies and one hypothetical case study.. In the first case study, the authors used the method to estimate that the oseltamivir-resistant seasonal influenza A H1N1 strain that emerged in 2007 was 4% more transmissible than its oseltamivir-sensitive predecessor. That finding indicated that even a small fitness advantage is sufficient for an AVR ...
During a pneumonic plague outbreak in Moramanga, Madagascar, we identified 4 confirmed, 1 presumptive, and 9 suspected plague case-patients. Human-to-human transmission among close contacts was high (reproductive number 1.44) and the case fatality rate was 71%. Phylogenetic analysis showed that the Yersinia pestis isolates belonged to group q3, different from the previous outbreak.
Basic reproduction numberEdit. Main article: Basic reproduction number. The basic reproduction number (. R. 0. {\displaystyle R ... where each λi may be real but in general is a complex number. The numbers λ1, λ2, … λn, which may not all have distinct values ... for any non-zero real number a. {\displaystyle a}. , is an eigenvector of A. {\displaystyle A}. with eigenvalue λ. =. 6. {\ ... Diekmann O, Heesterbeek JA, Metz JA (1990), "On the definition and the computation of the basic reproduction ratio R0 in models ...
Basic reproduction number Epidemic Mathematical modelling of infectious disease. ... λ = number of new infections number of susceptible persons exposed × average duration of exposure {\displaystyle \lambda ={\ ... frac {\mbox{number of new infections}}{{\mbox{number of susceptible persons exposed}}\times {\mbox{average duration of exposure ...
... the so-called basic reproduction number (also called basic reproduction ratio). This ratio is derived as the expected number of ... For this model, the basic reproduction number is: R 0 = a μ + a β μ + γ . {\displaystyle R_{0}={\frac {a}{\mu +a}}{\frac {\beta ... The role of the basic reproduction number is extremely important. In fact, upon rewriting the equation for infectious ... The model consists of three compartments- S for the number susceptible, I for the number of infectious, and R for the number ...
Reproduction numberEdit. Main article: Basic reproduction number. The basic reproduction number (denoted by R0) is a measure of ... As a consequence of this lower basic reproduction number, the average age of infection A will also change to some new value Aq ... The basic reproduction number (R0) of the disease, assuming everyone is susceptible, multiplied by the proportion of the ... The basic reproduction number can be computed as a ratio of known rates over time: if an infectious individual contacts β other ...
Basic reproduction number (basic reproductive rate, basic reproductive ratio, R0, or r nought) Stewart, AD; Logsdon, JM; Kelley ... This means that as a pathogen's ability to infect a greater number of hosts increases, so does the level of harm it brings to ...
New research has attempted to estimate the basic reproduction number, or R0 value, for Zika virus in several locations. ... "Preliminary estimation of the basic reproduction number of Zika virus infection during Colombia epidemic, 2015-2016". Travel ... Since the latter is an uncritical reproduction of the former, they are both considered to antedate the starting point for ... In the environment, the antidote is unavailable to rescue mosquito reproduction, so the pest population is suppressed. The ...
... the basic reproduction number can be calculated as the sum of the reproduction number for each transition time into the disease ... This quantity is called the basic reproduction number, denoted by R0, which can be defined as the number of secondary ... the basic reproduction number is R0 = β/γ This value quantifies the transmission potential of a disease. If the basic ... As a consequence of this lower basic reproduction number, the average age of infection A will also change to some new value Aq ...
Assuming a completely susceptible population, that means that the basic reproduction number (R0) of the infection must equal 1 ... the basic reproduction number multiplied by the proportion of susceptible individuals in the population (S) must be 1. This ... depending on a number of factors, including the virulence of the disease and its mode of transmission. If a disease is in ... the infection neither dies out nor does the number of infected people increase exponentially but the infection is said to be in ...
Ma E, Fung C, Yip SH, Wong C, Chuang SK, Tsang T (Aug 2011). "Estimation of the basic reproduction number of enterovirus 71 and ... The basic reproductive number (R0) for Coxsackievirus A16 (Cox A16) was estimated to a median of 2.50 with an interquartile ... and ultimately resulted in the isolation of a large number of so-called "enteric" viruses from the gastrointestinal tract that ...
Ma E, Fung C, Yip SH, Wong C, Chuang SK, Tsang T (Aug 2011). "Estimation of the basic reproduction number of enterovirus 71 and ... The basic reproductive number (R0) for enterovirus 71 (EV71) was estimated to a median of 5.48 with an interquartile range of ... Total number of cases of Hand Foot and Mouth Disease (HFMD) and herpangina in Taiwan was 129,106. The outbreaks of the ... Xinhua reported the number of people infected also rose from 4,000 to 15,799. Enteroviruses were isolated from a total of 1,892 ...
... is given by the equilibrium number of infected individuals, I {\displaystyle I} . The mean basic reproduction number, averaged ... The mean and variance of these individual basic reproduction numbers, E [ ν ] {\displaystyle \mathrm {E} [\nu ]} and V a r [ ν ... This finding aided in making an early estimate of the basic reproduction number R 0 {\displaystyle R_{0}} of the pandemic. ... These differences can be acknowledged by assuming that the basic reproduction number is a random variable ν {\displaystyle \nu ...
The basic reproduction number includes all secondary cases infected by a primary case, while x is only the number of secondary ... x is generally smaller than the basic reproduction number for the disease. That is defined as the number of individuals each ... If the number of susceptibles in the group is n and the number of secondary cases is x, then an estimation of the transmission ... There are a number of difficulties in using this relation. The first is that it is very difficult to measure contact rates ...
The basic reproduction number R0 is the average number of secondary infections caused by a typical infective person in a ... The basic reproductive number is found by multiplying the average number of contacts by the average probability that a ... R0 = Number of contacts X Shedding potential The individual reproductive number represents the number of secondary infections ... The greater the number of immunized individuals, the less likely an outbreak can occur because there are fewer susceptible ...
... incidence and basic reproduction number calculated from a cross-sectional serological survey on the island of Gozo, Malta. ...
In epidemiology, the next-generation matrix is a method used to derive the basic reproduction number, for a compartmental model ... 1990) and van den Driessche and Watmough (2002). To calculate the basic reproduction number by using a next-generation matrix, ...
... the basic reproduction number-in a large population when the initial number of infecteds is small, an infected individual is ... The following parameters are set initially: - Size of the population - Number of individuals already immune - Number of cases ( ... Let I t {\displaystyle I_{t}} represent the number of cases of infection at time t {\displaystyle t} . Assume all cases recover ... Let S t {\displaystyle S_{t}} represent the number of susceptible individuals at time t {\displaystyle t} . Let B ( x ) {\ ...
... an insurgent movement in Southern Thailand Basic reproduction number, a measure of the speed in which an epidemic spreads Berne ... ISO 3-letter country code Bulk Richardson number, meteorological number relating vertical stability and vertical shear Bunte ...
In medicine, transmissibility is a synonym for basic reproduction number Transmitter, a device for propagating electronic ...
... or R00 may refer to: Haplogroup R0, a gene R0, the Brussels Ring-road R0, basic reproduction number, an important concept in ...
This threshold can be calculated by taking R0, the basic reproduction number, or the average number of new infections caused by ... Althaus, C. L. (2014). "Estimating the Reproduction Number of Ebola Virus (EBOV) During the 2014 Outbreak in West Africa". PLoS ... Biggerstaff, M; Cauchemez, S; Reed, C; Gambhir, M; Finelli, L (2014). "Estimates of the reproduction number for seasonal, ... To account for this, the effective reproductive number Re, also written as Rt, or the average number of infections caused at ...
... basic reproduction number MeSH N01.224.935.597.500 --- incidence MeSH N01.224.935.597.750 --- prevalence MeSH N01.224.935.698 ...
Reproductions of these basic family structures exist in museums and tourist information sites, such as the structure at the ... A small number of these huts survive, and can be seen in the open air museums of Arnhem, Schoonoord, Barger-Compascuum and ... A large number of pithouses have been archaeologically excavated throughout the American Southwest. ... Although the architectural styles used by these people evolved throughout their history, the pithouse remained a basic ...
... the basic reproduction number for influenza is generally around 1.4). However, the generation time for influenza is extremely ... There are a number of rapid tests for the flu. One is called a Rapid Molecular Assay, when an upper respiratory tract specimen ... One important basic research program is the Influenza Genome Sequencing Project, which is creating a library of influenza ... A number of biologics, therapeutic vaccines and immunobiologics are also being investigated for treatment of infection caused ...
The farm has a large number of cows, buffalos, bulls (for reproduction), goats and sheep. Okara have all the basic physical and ... A large number of Rao are also found in the capital city of Islamabad, where they speak Urdu with Ranghari accent. Okara is ... Their 15th century folk sardar, Mir Chakar Rind, migrated from Sibi, with a large number of his people to this area and settled ... The population mostly relies on agriculture as their main source of livelihood, although a number of people work in factories ...
Almost all cells readily stain with a number of basic dyes due to the electrostatic attraction between negatively charged ... A host can be anything living and can attain to asexual and sexual reproduction.[41] The clearance of the pathogens, either ... A basic form of contagion theory was proposed by Persian physician Ibn Sina (known as Avicenna in Europe) in The Canon of ... Despite the huge number of wounds seen in clinical practice, there are limited quality data for evaluated symptoms and signs. A ...
In this variant, the number of f electrons in the most common (trivalent) ions of the f-block elements consistently matches ... Yttrium(III) oxide and lutetium(III) oxide exhibit weak basic character, but scandium(III) oxide is amphoteric.[48] Lanthanum( ... The element is known to damage cell membranes of water animals, causing several negative influences on reproduction and on the ... Ghiorso, Albert; Sikkeland, T.; Larsh, A. E.; Latimer, R. M. (1961). "New Element, Lawrencium, Atomic Number 103". Phys. Rev. ...
Existing estimates of the basic reproduction number, R0, for human schistosomes are mostly in the range 1-4, implying that ... Source: Tropical Medicine & International Health, Volume 1, Number 4, 1 August 1996, pp. 456-463(8) ...
... model is a parsimonious function that uses the basic reproduction number R0, along with a discounting factor to project the ... growth of outbreaks using only basic epidemiological information (e.g., daily incidence counts). Principal Findings Compared to ...
... also called the basic reproduction ratio or rate or the basic reproductive rate, is an epidemiologic metric used to describe ... R0 must be estimated, reported, and applied with great caution because this basic metric is far from simple. ... The basic reproduction number (R0), also called the basic reproduction ratio or rate or the basic reproductive rate, is an ... Volume 25, Number 1-January 2019 Perspective. Complexity of the Basic Reproduction Number (R0) On This Page ...
Basic reproduction number and transmission dynamics of common serogroups of enterohemorrhagic Escherichia coli. Shi Chen, ... The basic reproduction number (R0) was estimated using a Bayesian framework for each serogroup based on two criteria (using ... Importance and Highlights In this paper we describe a Bayesian modeling framework to estimate basic reproduction numbers of ... Basic reproduction number and transmission dynamics of common serogroups of enterohemorrhagic Escherichia coli ...
The basic reproduction number (R0) measures the epidemiological fitness of a pathogen in a given host population and is one of ... Basic Reproduction Number and Transmission Dynamics of Common Serogroups of Enterohemorrhagic Escherichia coli Shi Chen, ... The basic reproduction number (R 0) was estimated using a Bayesian framework for each serogroup based on two criteria (using ... Let I* (percentage of infection in the pen) be the steady state, and we can derive the pen-level basic reproduction number (R0 ...
2009 Mapping the basic reproduction number (R0) for vector-borne diseases: A case study on bluetongue virus. Epidemics, 1 (3). ... Mapping the basic reproduction number (R0) for vector-borne diseases: A case study on bluetongue virus ... Geographical maps indicating the value of the basic reproduction number, R0, can be used to identify areas of higher risk for ...
... and thus we conducted an uncertainty analysis of the basic reproduction number, R0. Methods A renewal process model was devised ... The basic reproduction number, R0, is interpreted as the average number of secondary cases that are produced by a single ... Univariate probability distribution of (A) the basic reproduction number, (B) a1 by December 11 and (C) a2 by December 12 from ... Corynebacterium diphtheriae, Diphtheria, Epidemiology, Outbreak, Basic reproduction number, Bangladesh, Refugee, Vaccination, ...
The basic reproduction number is not to be confused with the effective reproduction number R {\displaystyle R} , which is the ... or basic reproductive number , denoted R 0 {\displaystyle R_{0)) ,[17] of an infection can be thought of as the expected number ... Also, it is important to note that R 0 {\displaystyle R_{0)) is a dimensionless number and not a rate, which would have units ... number of cases generated in the current state of a population, which does not have to be the uninfected state. ...
The main objective of Discrete Dynamics in Nature and Society is to foster links between basic and applied research relating to ... 2. Basic Reproduction Number and Equilibria. The basic reproduction number , which can be explained as the average number of ... containing the origin, a positive number , and a real eigenvector of , such that(C1). for all ,(C2). for all ,(C3)the origin ... The basic reproduction number of the model has been calculated. The global asymptotic stability of the virus-free equilibrium ...
3. Basic Reproduction Number/Threshold Quantity. The basic reproduction number or the threshold quantity for the proposed model ... So, the reproduction number given by is Here, shows the disease-free equilibrium (DFE), and , giving . The endemic equilibrium ... In Section 3 we find the Basic Reproduction Number, the disease-free equilibrium, and endemic equilibrium of the proposed model ... First, we obtained the basic reproduction number for the proposed model. The disease-free equilibrium is locally as well as ...
We show that even the use of imperfect POC diagnostics can significantly reduce total costs and number of deaths, provided that ... Basic reproduction number. The basic reproduction number, \({ {\mathcal R} }_{0}\), for an infectious disease is the average ... The remaining reproduction numbers are in the Supplementary Material. The basic reproduction numbers are directly proportional ... The first term of the basic reproduction numbers shown below is the average number of secondary infections generated by a ...
On the Basic Reproduction Number of Reaction-Diffusion Epidemic Models. By Pierre Magal, Glenn F. Webb, and Yixiang Wu. SIAM ... The basic reproduction number $R_0$ serves as a threshold parameter of many epidemic models for disease... ...
As a result, we estimated that the basic reproductive number R0 ​is 3.11 in Beijing, 2.78 in Shanghai, 2.02 in Guangzhou, and ... As a result, we estimated that the basic reproductive number, R0, was 2.91 in Beijing, 2.78 in Shanghai, 2.02 in Guangzhou, and ... For example, in Beijing, the predicted peak number of cases was 46... ... the predicated peak number of cases is around 466 at the peak time Feb 29, 2020; however, when the city conducts different ...
Basic reproduction numberEdit. Main article: Basic reproduction number. The basic reproduction number (. R. 0. {\displaystyle R ... where each λi may be real but in general is a complex number. The numbers λ1, λ2, … λn, which may not all have distinct values ... for any non-zero real number a. {\displaystyle a}. , is an eigenvector of A. {\displaystyle A}. with eigenvalue λ. =. 6. {\ ... Diekmann O, Heesterbeek JA, Metz JA (1990), "On the definition and the computation of the basic reproduction ratio R0 in models ...
Results: The basic reproduction number fall between 2.8 and 3.3 by using the real-time reports on the number of 2019-nCoV- ... Impacts of different key parameters on the estimated basic reproduction numbers. The x‐axis is the number of cases with ... Preliminary prediction of the basic reproduction number of the Wuhan novel coronavirus 2019-nCoV Tao Zhou 1 , Quanhui Liu 2 , ... Preliminary prediction of the basic reproduction number of the Wuhan novel coronavirus 2019-nCoV Tao Zhou et al. J Evid Based ...
The basic reproduction number fall between 2.8 and 3.3 by using the real-time reports on the number of 2019-nCoV-infected cases ... Preliminary prediction of the basic reproduction number of the Wuhan novel coronavirus 2019-nCoV.. Zhou T1, Liu Q2, Yang Z3, ... To estimate the basic reproduction number of the Wuhan novel coronavirus (2019-nCoV). ... we estimate the basic reproduction number of 2019-nCoV according to the reported confirmed cases and suspected cases, as well ...
Basic reproduction number (R0): The average number of people that one person with COVID-19 is likely to infect in a population ... Parameter values for viral transmissibility include Doubling Time and Basic Reproduction Number (R0) ... The estimation of the basic reproduction number for infectious diseases. Stat Methods Med Res. 1993;2:23-41). ... Median number of days from symptom onset to hospitalization. *Median number of days of hospitalization among those not admitted ...
... we estimate the basic reproduction number R0 to be 1.6809 in China. Network modelling supplies a useful tool for studying the ... For the network model, we prove that the disease-free equilibrium is globally asymptotically stable when the basic reproduction ... The final size will depend on the vaccination starting time, T, the number of infective cases at time T and immunization ... Using the parameter estimates based on the observation data of the cumulative number of hospital notifications, ...
... mathematical modeling offers useful insights into the risk of a major epidemic of EVD and the assessment of the impact of basic ... The basic reproduction number, R0. The basic reproduction number, R 0, is interpreted as the average number of secondary cases ... Hence, in this model the basic reproduction number, R 0, is given by the following expression:. R. 0. =. β. 0. 1. /. γ. a. 0. + ... Importantly, the above components for the reproduction number underscore the fact that the actual reproduction number could ...
The present study corrects the concept of the actual reproduction number, offering a simple framework for estimating R0 without ... The basic reproduction number, R0, a summary measure of the transmission potential of an infectious disease, is estimated from ... The basic reproduction number, R0, a summary measure of the transmission potential of an infectious disease, is estimated from ... Keywords: transmission; infectious diseases; basic reproduction number; epidemiology; statistical model; estimation techniques ...
Furthermore, we estimated the basic reproduction number R0 of 1.7858, with an obtained 95% confidence interval for R0 of ( ... The reported number of the active tuberculosis cases is about one million each year. The morbidity data for 2005-2012 reflect ... basic reproduction number; global stability; data fitting; uncertainty and sensitivity analysis tuberculosis; age group; basic ... Furthermore, we estimated the basic reproduction number R0 of 1.7858, with an obtained 95% confidence interval for R0 of ( ...
We estimated the basic reproduction number (R 0) of these enteroviruses to obtain a better understanding of their transmission ... Basic reproduction number of coxsackievirus type A6 and A16 and enterovirus 71: estimates from outbreaks of hand, foot and ... Basic reproduction number of coxsackievirus type A6 and A16 and enterovirus 71: estimates from outbreaks of hand, foot and ... Basic reproduction number of coxsackievirus type A6 and A16 and enterovirus 71: estimates from outbreaks of hand, foot and ...
Estimating the basic reproduction number of COVID-19 in Wuhan, China Estimating the basic reproduction number of COVID-19 in ... The objectives of this study are 1) to estimate the basic reproduction number (R0) of COVID-19 reflecting the infectiousness of ... However, the estimations of the basic reproduction number of COVID-19 varied greatly across studies. ... and time dependent reproduction numbers (TD), were applied to estimate the [email protected]*[email protected]#Among the four methods, the EG method ...
The reproduction number decreased to 1.55 after social distancing interventions were implemented. ... we estimated the reproduction number as 4.4 (95% CI 3.9-4.9) by using a generalized growth model and 3.5 (95% CI 1.3-8.1) by ... we calculated basic reproduction numbers (R0). During the early transmission phase, R0 quantifies the average number of ... A) Growth rate, r; B) scaling of the growth rate parameter, p; C) mean basic reproduction number,... ...
Its basic reproduction number is 12 to 18.3 Only 1 other vaccine-preventable infectious agent is as contagious (Bordetella ... all others have a basic reproduction number that ranges from 4 to 7. Due to this contagiousness, a very high rate of community ...
  • Geographical maps indicating the value of the basic reproduction number, R0, can be used to identify areas of higher risk for an outbreak after an introduction. (nerc.ac.uk)
  • To determine the transmission potential of severe acute respiratory syndrome coronavirus 2 and thereby guide outbreak response efforts, we calculated basic reproduction numbers (R 0 ). (cdc.gov)
  • 0 range of 12-40 ( 1-5 ), meaning that 1 case introduced into of an outbreak-response vaccination campaign to onset a susceptible (naive) population will produce, on average, of an effective immune response of those vaccinated is that number of secondary cases. (cdc.gov)
  • A thought-provoking find from the SARS pandemic was that in the absence of super-spreading events, most infected individuals caused very few (if any) secondary contacts, but a low number of super-spreaders fueled the global outbreak. (novapublishers.com)
  • We estimated the basic (R 0 ) and effective (R e ) reproduction numbers for 7,094 norovirus outbreaks reported to the National Outbreak Reporting System (NORS) during 2009-2017 and used regression models to assess whether transmission varied by outbreak setting. (cdc.gov)
  • The recent Ebola virus outbreak in West Africa (2013-2016) resulted in 28,616 confirmed, probable, and suspected cases of Ebola virus disease and 11,310 deaths ( 6 ), which may still underestimate the actual numbers ( 7 ). (frontiersin.org)
  • It was the first Ebolavirus outbreak that affected multiple countries, was introduced to another country via air travel, and resulted in a significant number of human disease cases outside of Africa ( 5 , 6 ). (frontiersin.org)
  • The basic reproduction number $R_0$ and effectiveness of reactive interventions during dengue epidemics: The 2002 dengue outbreak in Easter Island, Chile. (aimsciences.org)
  • The greater the number of immunized individuals, the less likely an outbreak can occur because there are fewer susceptible contacts. (wikipedia.org)
  • Here they considered nonlinear saturating type incidence and they studied the effect of this type of incidence rate on the basic reproduction number and the equilibrium level of the infective population. (hindawi.com)
  • Some numerical results for the proposed parameters are presented which can reduce the number of infective in the population of humans. (aimsciences.org)
  • To estimate the basic reproduction number of the Wuhan novel coronavirus (2019-nCoV). (cdc.gov)
  • The basic reproduction number fall between 2.8 and 3.3 by using the real-time reports on the number of 2019-nCoV-infected cases from People's Daily in China and fall between 3.2 and 3.9 on the basis of the predicted number of infected cases from international colleagues. (cdc.gov)
  • December 1, 2019-January 22, 2020, we used the mean daily number of passengers traveling to the top 27 foreign destinations from Wuhan during 2018-2019, which were provided in other recent studies ( 1 - 3 ). (cdc.gov)
  • Zika in Rio de Janeiro: Assessment of basic reproduction number and comparison with dengue outbreaks. (nih.gov)
  • Such diseases tend to occur in cycles of outbreaks due to the variation in number of susceptibles (S(t)) over time. (wikipedia.org)
  • the authors used standard contact rate between susceptibles and alcoholism, getting alcoholism reproductive number and discussing the existence and stability of two equilibria. (hindawi.com)
  • The mathematical results show that the considered saturation effect in population of birds and psychological effect in population of human does not effect the stability of equilibria, if the disease is prevalent then it can affect the number of infected humans. (aimsciences.org)
  • N. Bacaër and R. Ouifki, Growth rate and basic reproduction number for population models with a simple periodic factor,, Mathematical Biosciences , 210 (2007), 647. (aimsciences.org)
  • First, we find the basic threshold quantity Ro and then find the local asymptotic stability of disease-free equilibrium and endemic equilibrium. (hindawi.com)
  • Immigrants for short visits and students should be subjected to tests to reduce the number of immigrants with disease. (hindawi.com)
  • For the network model, we prove that the disease-free equilibrium is globally asymptotically stable when the basic reproduction is less than one. (biomedcentral.com)
  • For the nonautonomous case, by introducing the basic reproduction number defined by the spectral radius, we study the uniform persistence and extinction of the disease. (hindawi.com)
  • In the constant controls case, by determining the basic reproduction number, we study the existence and stability of the disease-free and endemic steady-state solutions of the model. (hindawi.com)
  • The basic reproduction number ( denoted by R 0 ) is a measure of how transferable a disease is. (wikipedia.org)
  • Though it is very simple, this model exhibits the basic structure associated to the spread of a disease in a population. (omicsonline.org)
  • A metric that is often deployed to quantify the progress of the disease is the reproduction number, which is the expected number of secondary cases caused by a single infected individual over the infectious period. (smw.ch)
  • Alcohol damages almost all parts of the body and contribute to a number of human diseases including but not limited to liver cirrhosis, pancreatitis, heart disease, and sexual dysfunction and can eventually be deadly [ 8 ]. (hindawi.com)
  • The disease cannot break out again until the number of susceptibles has built back up as a result of offspring being born into the susceptible compartment. (wikipedia.org)
  • Every disease has a different 'basic reproduction number,' or R0, a measure of how contagious it is. (chicagotribune.com)
  • Here it is shown that reducing the basic reproduction number below one is not enough to eliminate the disease as backward bifurcation occurs for this model. (hindawi.com)
  • We first define the basic reproduction number $\mathcal{R}_0$ for the disease transmission, which generalizes the existing definition of $\mathcal{R}_0$ for the system in spatially homogeneous environment. (aimsciences.org)
  • We also derive the invasion reproduction numbers that determine whether or not a disease can invade into a population in which the other disease is endemic. (aimsciences.org)
  • The calculations of the invasion reproduction numbers suggest a new aspect in their interpretation - the class from which the initial disease carrier arises is important for understanding the invasion dynamics and biological interpretation of the expressions of the reproduction numbers. (aimsciences.org)
  • The basic reproduction number $\mathcal{R}_0$ is defined and evaluated directly for this model, and uniform persistence of the disease and threshold dynamics are obtained. (aimsciences.org)
  • The model has a disease-free equilibrium which is unstable when the basic reproduction number is greater than unity. (scirp.org)
  • For the disease, clustering always increases the basic reproduction number of the disease in networks with whether positive cluster or negative cluster. (aimsciences.org)
  • Despite the nonlinearity and complexity of the system, the basic reproduction number exhibits a nice linear property: it is simply the sum of two basic reproduction numbers for direct and indirect disease transmissions respectively. (aimsciences.org)
  • Even if the whole group in question is susceptible, x is generally smaller than the basic reproduction number for the disease. (wikipedia.org)
  • That is defined as the number of individuals each infected individual will go on to infect themselves, in a population with no resistance to the disease. (wikipedia.org)
  • Our analysis identifies a basic reproduction number that acts as a threshold between population extinction and persistence. (aimsciences.org)
  • In networks with double poisson distributions, power law-poisson distribution, poisson-power law distributions and double power law distributions, we find that cluster is positive(the clustering coefficient is increasing on the expected number of triangles) when the average degree of lines is fixed and the moment of triangles is less than some threshold. (aimsciences.org)
  • Once the moment of triangles exceeds that threshold, cluster will become negative(the clustering coefficient is decreasing on the expected number of triangles). (aimsciences.org)
  • The results show that for the periodic system the basic reproduction number is more accurate than the average reproduction number. (hindawi.com)
  • We also find that, with periodic intervention, the result is not much significantly different with constant intervention based on reduced number of the infected human population. (hindawi.com)
  • The basic reproduction number of discrete SIR and SEIS models with periodic parameters. (aimsciences.org)
  • The aim of this article is to provide formulas and properties of the basic reproduction number, $\mathcal R_0$, for a within-host virus model with periodic combination drug treatment. (aimsciences.org)
  • Remarks on basic reproduction ratios for periodic abstract functional differential equations. (aimsciences.org)
  • Rectangular and stationary age distribution , i.e., everybody in the population lives to age L and then dies, and for each age (up to L ) there is the same number of people in the population. (wikipedia.org)
  • However, in what became known as the 20/80 rule , an increasing number of studies and observations point towards a small number of individuals (20%) that are responsible for most (80%) transmission events in a population. (novapublishers.com)
  • To represent that the number of susceptible, infected and recovered individuals may vary over time (even if the total population size remains constant), we make the precise numbers a function of t (time): S(t), I(t) and R(t). (wikipedia.org)
  • The basic principles of insect population and suppression and management. (wikipedia.org)
  • The original purpose of branching processes was to serve as a mathematical model of a population in which each individual in generation n produces some random number of individuals in generation n + 1, according, in the simplest case, to a fixed probability distribution that does not vary from individual to individual. (wikipedia.org)
  • The South-central Black Rhinoceros, which lives in Zimbabwe, South Africa, and Tanzania, had a population of around 9,090 in 1980, but due to a wave of illegal poaching for its horn their numbers decreased to 1,300 in 1995. (wikipedia.org)
  • The population of Javan rhinos numbers only around 65-68 animals. (wikipedia.org)
  • A population with a size that increases geometrically is a population where generations of reproduction do not overlap. (wikipedia.org)
  • In each generation there is an effective population size denoted as Ne which constitutes the number of individuals in the population that are able to reproduce and will reproduce in any reproductive generation in concern. (wikipedia.org)
  • The number of new bacteria appearing per unit time is proportional to the present population. (wikipedia.org)
  • Oncofertility Saturday Academy (OSA) is a science program designed to engage a diverse population of high school girls from Chicago and San Diego to explore the basic science, clinical applications, and career options in reproductive science, cancer biology, and oncofertility. (wikipedia.org)
  • Media Centre, "Summary report of a WHO High-level meeting on Ebola vaccines access and financing," Tech. Rep., 2014, http://www.who.int/mediacentre/news/ebola/23-october-2014/en/ . (hindawi.com)
  • The model provides an approximate estimate of the basic reproduction number $\mathcal{R}_0=1.23$ in Xinjiang, China. (aimsciences.org)
  • The reproductive number $\mathcal R_0$ is derived. (aimsciences.org)
  • The results suggest that an effective strategy to contain vector-borne diseases is decreasing the basic reproduction number $\mathcal{R}_0$ below one. (aimsciences.org)
  • The parameters of the model included the reproduction number, the day of the first intervention and a reduction factor for the reproduction number. (smw.ch)
  • As implied by the variable function of t, the model is dynamic in that the numbers in each compartment may fluctuate over time. (wikipedia.org)
  • Controllability of a basic cochlea model. (aimsciences.org)
  • On the exact number of monotone solutions of a simplified Budyko climate model and their different stability. (aimsciences.org)
  • First, the basic reproduction number $\R_{0}$ is defined for this SIS PDE model. (aimsciences.org)
  • The basic model is the mixed mating model, which is based on the assumption that every fertilisation is either self-fertilisation or completely random cross-fertilisation. (wikipedia.org)
  • A number of countries purchased the Model 1900 Parabellum in 7.65×21 mm Parabellum (.30 Luger) caliber and issued the pistol on a limited basis to officers and mounted troops, including Germany, Switzerland, and the United States. (wikipedia.org)
  • And while the S scale market has seen a number of brass model manufacturers, today the major brass model supplier in S scale/S gauge is River Raisin Models. (wikipedia.org)
  • The traits of these objects are passed on through chromosomes by a means similar to biological reproduction. (wikipedia.org)
  • Many would regard his outstanding contribution to be his ability to see the coherent biological process behind reproduction, where his work is an outstanding example of translational research from experimental studies to clinical investigation of andrological disorders. (wikipedia.org)
  • Recently the Endocrine Society released a statement on endocrine-disrupting chemicals (EDCs) specifically listing obesity, diabetes, female reproduction, male reproduction, hormone-sensitive cancers in females, prostate cancer in males, thyroid, and neurodevelopment and neuroendocrine systems as being affected biological aspects of being exposed to EDCs. (wikipedia.org)
  • Afterwards, he received a Lecturer position in Biological Anthropology at University College London (1969-74) where he continued his research on the reproduction of mouse lemurs and comparative work on morphology of the skull, brain, postcranial skeleton and reproductive system in primates. (wikipedia.org)
  • Modern medicine is based on discoveries of basic biological research and their implementation in applied research. (wikipedia.org)
  • The basic reproduction number (R 0 ), pronounced "R naught," is intended to be an indicator of the contagiousness or transmissibility of infectious and parasitic agents. (cdc.gov)
  • The beginning of the epidemics is characterised by the basic reproduction number R 0 , whereas the effective reproduction number R t describes its progression in time. (smw.ch)
  • Next, we take the controls as time and formulate the appropriate optimal control problem and obtain the optimal control strategy to minimize both the number of infectious humans and the associated costs. (hindawi.com)
  • Here we present an online tool for the data-driven inference and quantification of uncertainties for the reproduction number, as well as the time points of interventions for 51 European countries. (smw.ch)
  • These variables (S, I, and R) represent the number of people in each compartment at a particular time. (wikipedia.org)
  • Super-spreaders have been identified who excrete a higher than normal number of pathogens during the time they are infectious. (wikipedia.org)
  • Khalid Masud learnt basics of Arabic and Persian from his father Saif U Rehman who was an Arabic teacher at his time. (wikipedia.org)
  • Studies show that most of their feeding time is spent on basic fruit which consumes around 80% of that time. (wikipedia.org)
  • 6. Group Size, Reproduction, and Time-Energy Budgets 7. (wikipedia.org)
  • Although viruses can differ with respect to many phenotypes, phylodynamic studies have to date tended to focus on a limited number of viral phenotypes. (wikipedia.org)
  • The design of speaker systems for Ambisonic playback is governed by several constraints: the desired spatial operating range (horizontal-only, hemispherical, full-sphere), the predominant resolution (= Ambisonic order) of the expected program material, the desired localisation performance and size of listening area versus the available number of speakers and amplification channels, and the theoretically optimal distribution of speakers versus the actually available placement and/or rigging options. (wikipedia.org)