scholarly journals The impact of infection-derived immunity on disease dynamics

2021 ◽  
Vol 83 (6-7) ◽  
Author(s):  
Adam Le ◽  
Aaron A. King ◽  
Felicia Maria G. Magpantay ◽  
Afshin Mesbahi ◽  
Pejman Rohani
Keyword(s):  
Infectious Diseases ◽  
Infected Individual ◽  
Population Level ◽  
Endemic Equilibrium ◽  
Disease Dynamics ◽  
Modes Of Failure ◽  
Long Run ◽  
The Impact

AbstractWhen modeling infectious diseases, it is common to assume that infection-derived immunity is either (1) non-existent or (2) perfect and lifelong. However there are many diseases in which infection-derived immunity is known to be present but imperfect. There are various ways in which infection-derived immunity can fail, which can ultimately impact the probability that an individual be reinfected by the same pathogen, as well as the long-run population-level prevalence of the pathogen. Here we discuss seven different models of imperfect infection-derived immunity, including waning, leaky and all-or-nothing immunity. For each model we derive the probability that an infected individual becomes reinfected during their lifetime, given that the system is at endemic equilibrium. This can be thought of as the impact that each of these infection-derived immunity failures have on reinfection. This measure is useful because it provides us with a way to compare different modes of failure of infection-derived immunity.

scholarly journals THE DYNAMICS OF THE RISK OF THE MORBIDITY AND THE ADAPTATION PROCESS AS INDICES OF THE IMPACT OF LOCAL ENVIRONMENTAL FACTORS ON THE POPULATION

2018 ◽  
Vol 97 (2) ◽  
pp. 124-131 ◽  
Author(s):  
V. M. Prusakov ◽  
Aleksandra V. Prusakova
Keyword(s):  
High Risk ◽  
Environmental Factors ◽  
Infectious Diseases ◽  
Absolute Magnitude ◽  
The Body ◽  
Adaptation Process ◽  
Disease Dynamics ◽  
Local Factors ◽  
The Impact

There were studied: The role of the disease dynamics at the background area in the formation of the risk for childhood morbidity in the study area; the value of indices of the long-term wavelike risk dynamics and the corresponding adaptation process for the identification and classification of mass non-infectious diseases. The waviness dynamics of the children morbidity risk is caused by the wave-like nature of the disease dynamics in the study and background areas. The disease risk level is formed not only by differences in the incidence rates of the background and study areas but also from differences in phases of high and low non-specific resistance of children contingent in these territories. The different character of the dynamics of the risk for the disease and related waviness of the adaptation process among children reflects the existence of differences in exposure to characteristics of local environmental factors in each territory. The average risk of disease, around which there are carried out annual fluctuations risks and phase states of the adaptation process, and the corresponding levels of reactivity and resistance of the body are the result of the absolute magnitude of the impact of local factors on the study area. The average relative risk of the morbidity, around which there are carried out annual fluctuations risks and phase states of the adaptation process is an integral index of the level of mass non-infectious diseases and the degree of severity of the medical and environmental situation, the level of reactivity and work mismatch of the body subsystems of children and the degree of their intensity. This is the measure of the absolute magnitude of the impact of local factors. The waviness to the development of states of high and low resistance is both always an index of antistress activation responses (or non-specifically high resistance state) and relative to the average force of impact factors (for the observed reactivity level). On the basis of the accounting for the level of the risk, there is suggested the classification of infectious diseases, including 1) the background or relatively satisfactory morbidity, 2) mass morbidity with the increased risk, 3) mass incidence of the high-risk, and 4) a mass incidence of the very high risk.

scholarly journals Exogenous re-infection and the dynamics of tuberculosis epidemics: local effects in a network model of transmission

2006 ◽  
Vol 4 (14) ◽  
pp. 523-531 ◽  
Author(s):  
Ted Cohen ◽  
Caroline Colijn ◽  
Bryson Finklea ◽  
Megan Murray
Keyword(s):  
Network Model ◽  
Disease Transmission ◽  
Control Strategies ◽  
Disease Incidence ◽  
Infected Individual ◽  
Population Level ◽  
Recent Infection ◽  
Tb Control ◽  
Relative Contribution ◽  
The Impact

Infection with Mycobacterium tuberculosis leads to tuberculosis (TB) disease by one of the three possible routes: primary progression after a recent infection; re-activation of a latent infection; or exogenous re-infection of a previously infected individual. Recent studies show that optimal TB control strategies may vary depending on the predominant route to disease in a specific population. It is therefore important for public health policy makers to understand the relative frequency of each type of TB within specific epidemiological scenarios. Although molecular epidemiologic tools have been used to estimate the relative contribution of recent transmission and re-activation to the burden of TB disease, it is not possible to use these techniques to distinguish between primary disease and re-infection on a population level. Current estimates of the contribution of re-infection therefore rely on mathematical models which identify the parameters most consistent with epidemiological data; these studies find that exogenous re-infection is important only when TB incidence is high. A basic assumption of these models is that people in a population are all equally likely to come into contact with an infectious case. However, theoretical studies demonstrate that the social and spatial structure can strongly influence the dynamics of infectious disease transmission. Here, we use a network model of TB transmission to evaluate the impact of non-homogeneous mixing on the relative contribution of re-infection over realistic epidemic trajectories. In contrast to the findings of previous models, our results suggest that re-infection may be important in communities where the average disease incidence is moderate or low as the force of infection can be unevenly distributed in the population. These results have important implications for the development of TB control strategies.

Climate Change and Infectious Diseases; Evidence from Highly Vulnerable Countries

2020 ◽  
Author(s):  
Asim ANWAR ◽  
Sajid ANWAR ◽  
Muhammad AYUB ◽  
Faisal NAWAZ ◽  
Shabir HYDER ◽  
...  
Keyword(s):  
Climate Change ◽  
Infectious Diseases ◽  
Town Planning ◽  
Economic Factors ◽  
Mediating Role ◽  
Panel Ardl ◽  
Country Level ◽  
Long Run ◽  
The Impact ◽  
Socio Economic Factors

Background: Climate change is an alarming challenge for humanity at large due to its mediating role in emergence and spread of infectious diseases like cholera and malaria. This study was conducted to examine the effect of climate change and some socio-economic factors on incidence of infectious diseases. Methods: We used country level panel data over the 1990-2017 period using panel ARDL-PMG technique on highly affected countries from climate change. Results: There is a long run co-integrating relationship among climate change, socio-economic factors and prevalence of infectious diseases. Climate change, as measured by the temperature, is contributing to the spread of infectious diseases. Conclusion: This is the first study giving evidence of the impact of climate change on incidence of infectious diseases as can be seen from highly vulnerable countries to climate change. It is recommended to improve the level of education along with public health and town planning to reduce the incidence of infectious diseases.    

scholarly journals Inferring high-resolution human mixing patterns for disease modeling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dina Mistry ◽  
Maria Litvinova ◽  
Ana Pastore y Piontti ◽  
Matteo Chinazzi ◽  
Laura Fumanelli ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Disease Transmission ◽  
Disease Modeling ◽  
Population Level ◽  
Effective Population ◽  
Human Contact ◽  
Contact Patterns ◽  
Data Driven Approach ◽  
Mixing Patterns ◽  
The Impact

AbstractMathematical and computational modeling approaches are increasingly used as quantitative tools in the analysis and forecasting of infectious disease epidemics. The growing need for realism in addressing complex public health questions is, however, calling for accurate models of the human contact patterns that govern the disease transmission processes. Here we present a data-driven approach to generate effective population-level contact matrices by using highly detailed macro (census) and micro (survey) data on key socio-demographic features. We produce age-stratified contact matrices for 35 countries, including 277 sub-national administratvie regions of 8 of those countries, covering approximately 3.5 billion people and reflecting the high degree of cultural and societal diversity of the focus countries. We use the derived contact matrices to model the spread of airborne infectious diseases and show that sub-national heterogeneities in human mixing patterns have a marked impact on epidemic indicators such as the reproduction number and overall attack rate of epidemics of the same etiology. The contact patterns derived here are made publicly available as a modeling tool to study the impact of socio-economic differences and demographic heterogeneities across populations on the epidemiology of infectious diseases.

scholarly journals The duration of travel impacts the spatial dynamics of infectious diseases

2020 ◽  
Vol 117 (36) ◽  
pp. 22572-22579 ◽  
Author(s):  
John R. Giles ◽  
Elisabeth zu Erbach-Schoenberg ◽  
Andrew J. Tatem ◽  
Lauren Gardner ◽  
Ottar N. Bjørnstad ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Mobile Phone ◽  
Disease Transmission ◽  
Human Mobility ◽  
Trip Duration ◽  
Disease Dynamics ◽  
Mobility Patterns ◽  
Spatial And Temporal Scales ◽  
The Impact ◽  
Spatial Transmission

Humans can impact the spatial transmission dynamics of infectious diseases by introducing pathogens into susceptible environments. The rate at which this occurs depends in part on human-mobility patterns. Increasingly, mobile-phone usage data are used to quantify human mobility and investigate the impact on disease dynamics. Although the number of trips between locations and the duration of those trips could both affect infectious-disease dynamics, there has been limited work to quantify and model the duration of travel in the context of disease transmission. Using mobility data inferred from mobile-phone calling records in Namibia, we calculated both the number of trips between districts and the duration of these trips from 2010 to 2014. We fit hierarchical Bayesian models to these data to describe both the mean trip number and duration. Results indicate that trip duration is positively related to trip distance, but negatively related to the destination population density. The highest volume of trips and shortest trip durations were among high-density districts, whereas trips among low-density districts had lower volume with longer duration. We also analyzed the impact of including trip duration in spatial-transmission models for a range of pathogens and introduction locations. We found that inclusion of trip duration generally delays the rate of introduction, regardless of pathogen, and that the variance and uncertainty around spatial spread increases proportionally with pathogen-generation time. These results enhance our understanding of disease-dispersal dynamics driven by human mobility, which has potential to elucidate optimal spatial and temporal scales for epidemic interventions.

scholarly journals THE COMORBIDITY IN EPIDEMIOLOGY - NEW TREND IN PUBLIC HEALTH RESEARCH

2016 ◽  
pp. 66-75 ◽  
Author(s):  
E. D. Savilov ◽  
S. I. Kolesnikov ◽  
N. I. Briko
Keyword(s):  
Public Health ◽  
Risk Factors ◽  
Infectious Diseases ◽  
Environmental Pollution ◽  
Population Level ◽  
Anthropogenic Pollution ◽  
Public Health Research ◽  
New Approach ◽  
Somatic Diseases ◽  
The Impact

Comorbidity epidemiological aspects discussed in the article. At the present time most common on the population level are research of the impact of infectious diseases on the macroorganism at the population level, or investigations of dynamics of noninfectious diseases under influence of several risk factors. The problem of coexistence (comorbidity) of infectious diseases with other nosologic forms usually are not considered. Some examples of simultaneous effect (comorbidity) of infectious and somatic diseases on the macroorganism under the influence of anthropogenic pollution are shown in the article. Environmental pollution is usually not taking into consideration third force which affects the development of comorbidity. Proposed new approach allowed differently interpret previously obtained materials and introduce additional variable risk factors in the chain of causal relationships between infectious disease and environmental pollution

scholarly journals Modeling the Impact of Vaccination, Screening, Treatment on the Dynamics of Pneumonia

2020 ◽  
Vol 12 (4) ◽  
pp. 525-536
Author(s):  
K. S. Rahman ◽  
S. R. Mitkari ◽  
S. Shaikh
Keyword(s):  
Equilibrium Point ◽  
Deterministic Model ◽  
Reproduction Number ◽  
Equilibrium Points ◽  
Infected Individual ◽  
Nonlinear Ordinary Differential Equation ◽  
Endemic Equilibrium ◽  
Natural Immunity ◽  
The Stability ◽  
The Impact

In this paper we have presented a deterministic model for pneumonia transmission and we have used the model to avail the potential impact of therapy. The model is based on the vaccinated-susceptible-carrier-infected-recovered-susceptible compartmental structure and their possible interventions with the possibility of infected individual recovery from natural immunity. Here, we have modeled Pneumonia considering vaccination, screening and treatment with a system of nonlinear ordinary differential equation. The model reproduction number R0 is derived and the stability of the equilibria are derived. The stability of equilibrium points is analyzed. The results shows that there exists a locally stable disease free equilibrium points, E0 when R0<1 and a unique endemic equilibrium E1, when R0>1. Infection free point was found to be locally stable and if reproduction number is greater than unity, then there is unique endemic equilibrium point and if it is less than unity, the endemic equilibrium point is globally asymptotically stable and pneumonia will be eliminated.

The long-run stability of a small, open economy under crawling peg regime

2002 ◽  
Vol 52 (1) ◽  
pp. 57-78
Author(s):  
S. Çiftçioğlu
Keyword(s):  
Exchange Rate ◽  
Open Economy ◽  
Risk Premium ◽  
Small Open Economy ◽  
Exchange Rate Policy ◽  
Price Stability ◽  
Output Stability ◽  
Long Run ◽  
The Exchange Rate ◽  
The Impact

The paper analyses the long-run (steady-state) output and price stability of a small, open economy which adopts a “crawling-peg” type of exchange-rate regime in the presence of various kinds of random shocks. Analytical and simulation results suggest that with the exception of money demand shocks, an exchange rate policy which involves a relatively higher rate of indexation of the exchange rate to price level is likely to lead to the worsening of price stability for all types of shocks. On the other hand, the impact of adopting such a policy on output stability depends on the type of the shock; for policy shocks to the exchange rate and shocks to output demand, output stability is worsened whereas for the shocks to risk premium of domestic assets, supply price of domestic output and the wage rate, better output stability is achieved in the long run.

Impact of exchange rate and oil price on the yield of sovereign bond and sukuk: Evidence from Malaysian capital market

2017 ◽  
Vol 5 (4) ◽  
pp. 27
Author(s):  
Huda Arshad ◽  
Ruhaini Muda ◽  
Ismah Osman
Keyword(s):  
Exchange Rate ◽  
Capital Market ◽  
Time Series Data ◽  
Oil Prices ◽  
Oil Price ◽  
Series Data ◽  
Sovereign Bond ◽  
Long Run ◽  
Short Run ◽  
The Impact

This study analyses the impact of exchange rate and oil prices on the yield of sovereign bond and sukuk for Malaysian capital market. This study aims to ascertain the effect of weakening Malaysian Ringgit and declining of crude oil price on the fixed income investors in the emerging capital market. This study utilises daily time series data of Malaysian exchange rate, oil price and the yield of Malaysian sovereign bond and sukuk from year 2006 until 2015. The findings show that the weakening of exchange rate and oil prices contribute different impacts in the short and long run. In the short run, the exchange rate and oil prices does not have a direct relation with the yield of sovereign bond and sukuk. However, in the long run, the result reveals that there is a significant relationship between exchange rate and oil prices on the yield of sovereign bond and sukuk. It is evident that only a unidirectional causality relation is present between exchange rate and oil price towards selected yield of Malaysian sovereign bond and sukuk. This study provides numerical and empirical insights on issues relating to capital market that supports public authorities and private institutions on their decision and policymaking process.

Awareness of symptomatic differences Covid-19, SARS, Swine Flu, Common cold among dental students

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1026-1033
Author(s):  
Nivedha Valliammai Mahalingam ◽  
Abilasha R ◽  
Kavitha S
Keyword(s):  
Infectious Diseases ◽  
Undergraduate Students ◽  
Common Cold ◽  
Emerging Infectious Diseases ◽  
Dental Students ◽  
Swine Flu ◽  
Viral Diseases ◽  
Surveillance Systems ◽  
Cross Sectional ◽  
The Impact

Enormous successes have been obtained against the control of major epidemic diseases, such as SARS, MERS, Ebola, Swine Flu in the past. Dynamic interplay of biological, socio-cultural and ecological factors, together with novel aspects of human-animal interphase, pose additional challenges with respect to the emergence of infectious diseases. The important challenges faced in the control and prevention of emerging and re-emerging infectious diseases range from understanding the impact of factors that are necessary for the emergence, to development of strengthened surveillance systems that can mitigate human suffering and death. The aim of the current study is to assess the awareness of symptomatic differences between viral diseases like COVID-19, SARS, Swine flu and common cold among dental students that support the prevention of emergence or re-emergence. Cross-sectional type of study conducted among the undergraduate students comprising 100 Subjects. A questionnaire comprising 15 questions in total were framed, and responses were collected in Google forms in SPSS Software statistical analysis. The study has concluded that dental students have an awareness of the symptomatic differences between infectious viral disease. The study concluded that the awareness of symptomatic differences between viral diseases like COVID-19, SARS, Swine flu, Common cold is good among the dental students who would pave the way for early diagnosis and avoid spreading of such diseases. A further awareness can be created by regular webinars, seminars and brainstorming sessions among these healthcare professionals.

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