scholarly journals Differential impacts of contact tracing and lockdowns on outbreak size in COVID-19 model applied to China

2020 ◽  
Author(s):  
Cameron J. Browne ◽  
Hayriye Gulbudak ◽  
Joshua C. Macdonald
Keyword(s):  
Disease Model ◽  
Critical Time ◽  
Fundamental Principle ◽  
Contact Tracing ◽  
Final Size ◽  
Infectious Disease Model ◽  
Epidemic Curve ◽  
Time Period ◽  
Current Infection ◽  
Outbreak Size

Rapid growth of the COVID-19 epidemic in China induced extensive efforts of contact tracing and social-distancing/lockdowns, which quickly contained the outbreak and has been replicated to varying degrees around the world. We construct a novel infectious disease model incorporating these distinct quarantine measures (contact tracing and self-quarantine) as reactionary interventions dependent on current infection levels. Derivation of the final outbreak size leads to a simple inverse proportionality relationship with self-quarantine rate, revealing a fundamental principle of exponentially increasing cumulative cases when delaying mass quarantine or lockdown measures beyond a critical time period. In contrast, contact tracing results in a proportional reduction in reproduction number, flattening the epidemic curve but only having sizable impact on final size when a large proportion of contacts are “perfectly” traced. We fit the mathematical model to data from China on reported cases and quarantined contacts, finding that lockdowns had an overwhelming influence on outbreak size and duration, whereas contact tracing played a role in reducing peak number of infected. Sensitivity analysis and simulations under different re-opening scenarios illustrate the differential effects that responsive contact tracing and lockdowns can have on current and second wave outbreaks.

scholarly journals Investigating Dynamics of COVID-19 Spread and Containment with Agent-Based Modeling

2021 ◽  
Vol 11 (12) ◽  
pp. 5367
Author(s):  
Amirarsalan Rajabi ◽  
Alexander V. Mantzaris ◽  
Ece C. Mutlu ◽  
Ozlem O. Garibay
Keyword(s):  
Disease Model ◽  
Agent Based Modeling ◽  
Contact Tracing ◽  
Test Bed ◽  
Policy Makers ◽  
Agent Based ◽  
Contact Behavior ◽  
Epidemic Curve ◽  
Behavioral Adaptations ◽  
Travel Restrictions

Governments, policy makers, and officials around the globe are working to mitigate the effects of the COVID-19 pandemic by making decisions that strive to save the most lives and impose the least economic costs. Making these decisions require comprehensive understanding of the dynamics by which the disease spreads. In traditional epidemiological models, individuals do not adapt their contact behavior during an epidemic, yet adaptive behavior is well documented (i.e., fear-induced social distancing). In this work we revisit Epstein’s “coupled contagion dynamics of fear and disease” model in order to extend and adapt it to explore fear-driven behavioral adaptations and their impact on efforts to combat the COVID-19 pandemic. The inclusion of contact behavior adaptation endows the resulting model with a rich dynamics that under certain conditions reproduce endogenously multiple waves of infection. We show that the model provides an appropriate test bed for different containment strategies such as: testing with contact tracing and travel restrictions. The results show that while both strategies could result in flattening the epidemic curve and a significant reduction of the maximum number of infected individuals; testing should be applied along with tracing previous contacts of the tested individuals to be effective. The results show how the curve is flattened with testing partnered with contact tracing, and the imposition of travel restrictions.

scholarly journals A New Approach to the Dynamic Modeling of an Infectious Disease

2020 ◽  
Author(s):  
B Shayak ◽  
Mohit M Sharma
Keyword(s):  
Infectious Disease ◽  
Immune Response ◽  
A Priori ◽  
Disease Model ◽  
Public Health Intervention ◽  
Contact Tracing ◽  
Infectious Disease Model ◽  
Lumped Parameter ◽  
Computational Requirement ◽  
Delay Differential

ABSTRACTIn this work we propose a delay differential equation as a lumped parameter or compartmental infectious disease model featuring high descriptive and predictive capability, extremely high adaptability and low computational requirement. Whereas the model has been developed in the context of COVID-19, it is general enough to be applicable mutatis mutandis to other diseases as well. Our fundamental modeling philosophy consists of a decoupling of public health intervention effects, immune response effects and intrinsic infection properties into separate terms. All parameters in the model are directly related to the disease and its management; we can measure or calculate their values a priori basis our knowledge of the phenomena involved, instead of having to extrapolate them from solution curves. Our model can accurately predict the effects of applying or withdrawing interventions, individually or in combination, and can quickly accommodate any newly released information regarding, for example, the infection properties and the immune response to an emerging infectious disease. After demonstrating that the baseline model can successfully explain the COVID-19 case trajectories observed all over the world, we systematically show how the model can be expanded to account for heterogeneous transmissibility, detailed contact tracing drives, mass testing endeavours and immune responses featuring different combinations of limited-time sterilizing immunity, severity-reducing immunity and antibody dependent enhancement.

Maternal care and environmental enrichment influences on serotonin knockout mice with implications for a gene x stress model of autism

2019 ◽  
Author(s):  
◽  
Briana M. Kille
Keyword(s):  
Serotonin Transporter ◽  
Maternal Care ◽  
Environmental Enrichment ◽  
Environmental Influence ◽  
Repetitive Behavior ◽  
Critical Time ◽  
University Of Missouri ◽  
Time Period ◽  
Maternal Genotype ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Previous research has shown a genetic variant in the serotonin transporter gene (Slc6a4) can increase the severity of a person's reaction to stress. This variant interacts with environmental stressors resulting in poorer health outcomes. Previous studies have also found that stressing pregnant mothers who carry the variant can result in an increased likelihood of autism diagnosis for the child. This maternal genotype x prenatal stress interaction has been modeled in the serotonin transporter knockout (SERT KO) mouse--dams genetically modified to mimic humans carrying the short allele were stressed during pregnancy resulting in offspring showing altered social behavior, repetitive behavior, and anxiety behavior. The first study included in this dissertation attempted to replicate this model while using a foster dam paradigm to avoid potential maternal care confounds. Surprisingly, the results showed that equalizing maternal care equalized several group differences in behavior. It is theorized that this is due to elimination of the neonatal insult from poor maternal care that would correspond to a human prenatal insult during a previously identified critical time period. The second study explored the potential effects environmentally enriched home cages on anxiety like behaviors of SERT KO mice. The study showed that all animals, regardless of genotype, showed fewer anxiety like behaviors in the open field assay. Together, these studies expand on our understanding of environmental influence on SERT KO mice used in translational studies.

scholarly journals Obesity as an "infectious" disease

2021 ◽  
Vol 11 (9) ◽  
pp. 534-537
Author(s):  
Daria Żuraw ◽  
Paulina Oleksa ◽  
Mateusz Sobczyk
Keyword(s):  
Infectious Disease ◽  
Disease Model ◽  
Living Environment ◽  
Social Contagion ◽  
Social Discrimination ◽  
Obese People ◽  
Obesity Epidemic ◽  
Global Epidemic ◽  
Infectious Disease Model ◽  
The One

Introduction: Obesity has been recognized as a global epidemic by the WHO, followed by a wealth of empirical evidence supporting its contagiousness. However, the dynamics of the spread of obesity between individuals are rarely studied.  A distinguishing feature of the obesity epidemic is that it is driven by a process of social contagion that cannot be perfectly described by the infectious disease model. There is also social discrimination in the obesity epidemic. Social discrimination against obese people plays quite different roles in two cases: on the one hand, when obesity cannot be eliminated, social discrimination can reduce the number of obese people; on the other hand, when obesity is eradicable, social discrimination can cause it to explode.(1)   Materiał and methods: A literature analysis on obesity epidemic was carried out within the Pubmed, Google scholar and Research Gate platform. The following keywords were used in serach: obesity, epidemy, children, body max index.    Purpose of the work: The aim of the following analysis is to present an obesity as an infectious disease. The steadily increasing percentage of obese people, including children, shows that there is an obesity epidemic. This is the phenomenon of social contagion, which partially explains the concept of homophily, which involves the grouping of people with similar characteristics. Potential explanations are also provided by sharing a living environment with similar access to certain foods and similar opportunities for physical activity, which defines the occurrence of analogous health habits

scholarly journals How public perceptions of social distancing evolved over a critical time period: communication lessons learnt from the American state of Wisconsin

2020 ◽  
Vol 19 (05) ◽  
pp. A11
Author(s):  
Kaiping Chen ◽  
Luye Bao ◽  
Anqi Shao ◽  
Pauline Ho ◽  
Shiyu Yang ◽  
...  
Keyword(s):  
Public Health ◽  
Computational Methods ◽  
Large Scale ◽  
Critical Time ◽  
Effective Communication ◽  
Public Perceptions ◽  
Social Distancing ◽  
Time Period ◽  
Large Scale Survey ◽  
Main Barrier

Understanding how individuals perceive the barriers and benefits of precautionary actions is key for effective communication about public health crises, such as the COVID-19 outbreak. This study used innovative computational methods to analyze 30,000 open-ended responses from a large-scale survey to track how Wisconsin (U.S.A.) residents' perceptions of the benefits of and barriers to performing social distancing evolved over a critical time period (March 19th to April 1st, 2020). Initially, the main barrier was practical related, however, individuals later perceived more multifaceted barriers to social distancing. Communication about COVID-19 should be dynamic and evolve to address people's experiences and needs overtime.

scholarly journals The importance of elastin to aortic development in mice

2010 ◽  
Vol 299 (2) ◽  
pp. H257-H264 ◽  
Author(s):  
Jessica E. Wagenseil ◽  
Christopher H. Ciliberto ◽  
Russell H. Knutsen ◽  
Marilyn A. Levy ◽  
Attila Kovacs ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Critical Time ◽  
Left Ventricular ◽  
Critical Threshold ◽  
Cardiovascular Development ◽  
Mouse Development ◽  
Hemodynamic Forces ◽  
Time Period ◽  
Stenotic Arteries ◽  
And Function

Elastin is an essential component of vertebrate arteries that provides elasticity and stores energy during the cardiac cycle. Elastin production in the arterial wall begins midgestation but increases rapidly during the last third of human and mouse development, just as blood pressure and cardiac output increase sharply. The aim of this study is to characterize the structure, hemodynamics, and mechanics of developing arteries with reduced elastin levels and determine the critical time period where elastin is required in the vertebrate cardiovascular system. Mice that lack elastin ( Eln−/−) or have approximately one-half the normal level ( Eln+/−) show relatively normal cardiovascular development up to embryonic day (E) 18 as assessed by arterial morphology, left ventricular blood pressure, and cardiac function. Previous work showed that just a few days later, at birth, Eln−/− mice die with high blood pressure and tortuous, stenotic arteries. During this period from E18 to birth, Eln+/− mice add extra layers of smooth muscle cells to the vessel wall and have a mean blood pressure 25% higher than wild-type animals. These findings demonstrate that elastin is only necessary for normal cardiovascular structure and function in mice starting in the last few days of fetal development. The large increases in blood pressure during this period may push hemodynamic forces over a critical threshold where elastin becomes required for cardiovascular function. Understanding the interplay between elastin amounts and hemodynamic forces in developing vessels will help design treatments for human elastinopathies and optimize protocols for tissue engineering.

Environmentally Useful Life of Interlocking Concrete Block Pavements: Critical Time Period Concept

2021 ◽  
Vol 7 (2) ◽  
pp. 04021001
Author(s):  
Arya Chandralal Anitha ◽  
Muhammed Siddik Abdul Samad ◽  
George K. Varghese
Keyword(s):  
Critical Time ◽  
Concrete Block ◽  
Time Period ◽  
Useful Life
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