scholarly journals Capping Mobility to Control COVID-19: A Collision-based Infectious Disease Transmission Model

2020 ◽  
Author(s):  
Yunfeng Shi ◽  
Xuegang Ban
Keyword(s):  
New York ◽  
Disease Transmission ◽  
The United States ◽  
Transmission Model ◽  
Infected People ◽  
Gas Phase Chemistry ◽  
Mobility Data ◽  
Simple Kinetic Model ◽  
Phase Chemistry ◽  
Disease Transmission Model

We developed a mobility-informed disease-transmission model for COVID-19, inspired by collision theory in gas-phase chemistry. This simple kinetic model leads to a closed-form infectious population as a function of time and cumulative mobility. This model uses fatality data from Johns Hopkins to infer the infectious population in the past, and mobility data from Google, without social-distancing policy, geological or demographic inputs. It was found that the model appears to be valid for twenty hardest hit counties in the United States. Based on this model, the number of infected people grows (shrinks) exponentially once the relative mobility exceeds (falls below) a critical value (~30% for New York City and ~60% for all other counties, relative to a median mobility from January 3 to February 6, 2020). A simple mobility cap can be used by government at different levels to control COVID-19 transmission in reopening or imposing another shutdown.

scholarly journals Differential effects of intervention timing on COVID-19 spread in the United States

2020 ◽  
Vol 6 (49) ◽  
pp. eabd6370 ◽  
Author(s):  
Sen Pei ◽  
Sasikiran Kandula ◽  
Jeffrey Shaman
Keyword(s):  
United States ◽  
Disease Transmission ◽  
Human Mobility ◽  
The United States ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Transmission Model ◽  
Reproductive Number ◽  
Mobility Data ◽  
Nonpharmaceutical Interventions

Assessing the effects of early nonpharmaceutical interventions on coronavirus disease 2019 (COVID-19) spread is crucial for understanding and planning future control measures to combat the pandemic. We use observations of reported infections and deaths, human mobility data, and a metapopulation transmission model to quantify changes in disease transmission rates in U.S. counties from 15 March to 3 May 2020. We find that marked, asynchronous reductions of the basic reproductive number occurred throughout the United States in association with social distancing and other control measures. Counterfactual simulations indicate that, had these same measures been implemented 1 to 2 weeks earlier, substantial cases and deaths could have been averted and that delayed responses to future increased incidence will facilitate a stronger rebound of infections and death. Our findings underscore the importance of early intervention and aggressive control in combatting the COVID-19 pandemic.

scholarly journals Predicting the Time to Detect Moderately Virulent African Swine Fever Virus in Finisher Swine Herds Using a Stochastic Disease Transmission Model

2021 ◽  
Author(s):  
Sasidhar Malladi ◽  
Amos Ssematimba ◽  
Peter J. Bonney ◽  
Kaitlyn M. St. Charles ◽  
Timothy Boyer ◽  
...  
Keyword(s):  
Disease Transmission ◽  
African Swine Fever Virus ◽  
Clinical Signs ◽  
African Swine Fever ◽  
The United States ◽  
Disease Spread ◽  
Transmission Model ◽  
Economic Losses ◽  
Parameter Estimates ◽  
Disease Transmission Model

Abstract Background: African swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains. Using an approximate Bayesian computation algorithm in conjunction with Monte Carlo simulation, we have estimated the adequate contact rate for moderately virulent ASFV strains and determined the statistical distributions for the durations of mild and severe clinical signs using individual, pig-level data. A discrete individual based disease transmission model was then used to estimate the time to detect ASF infection based on increased mild clinical signs, severe clinical signs, or daily mortality. Results: Our results indicate that it may take two weeks or longer to detect ASF in a finisher swine herd via mild clinical signs or increased mortality beyond levels expected in routine production. A key factor contributing to the extended time to detect ASF in a herd is the fairly long latently infected period for an individual pig (mean 4.5, 95% P.I., 2.4 - 7.2 days). Conclusion: These transmission model parameter estimates and estimated time to detection via clinical signs provide valuable information that can be used not only to support emergency preparedness but also to inform other simulation models of evaluating regional disease spread.

Lyapunov functions for a dengue disease transmission model

2009 ◽  
Vol 39 (2) ◽  
pp. 936-941 ◽  
Author(s):  
Jean Jules Tewa ◽  
Jean Luc Dimi ◽  
Samuel Bowong
Keyword(s):  
Disease Transmission ◽  
Lyapunov Functions ◽  
Transmission Model ◽  
Dengue Disease ◽  
Disease Transmission Model

scholarly journals LB16. The Role of Adults in the Measles Outbreak in New York State Outside of New York City, 2018–2019

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S1000-S1000
Author(s):  
Elizabeth Dufort ◽  
Dylan Johns ◽  
Manisha Patel ◽  
Manisha Patel ◽  
Nina Ahmad ◽  
...  
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Disease Transmission ◽  
New York State ◽  
The United States ◽  
Case Definition ◽  
Material Support ◽  
Measles Outbreak ◽  
Collaborative Agreement

Abstract Background The United States is experiencing the largest measles outbreak since elimination was declared in 2000, with the majority of cases in NYS reported in undervaccinated communities. The objective of this evaluation was to describe adult measles cases in the NYS measles outbreak outside of New York City (NYC). Methods We included all confirmed cases aged ≥18 years in NYS residents (excluding NYC) during October 1, 2018–July 25, 2019 that met the CSTE measles case definition. We defined measles cases attributable to adults as the sum of measles cases among adults and children who contracted disease directly from adults. Results Among 371 confirmed measles cases, the median age was 5.5 years (range: 1 day to 64 years); 79 (21%) were in adults, 4 (5%) of whom were born before 1957 (3 unvaccinated and 1 with unknown vaccine status). Among the 75 cases born during or after 1957, 65 (87%) were unvaccinated or had unknown vaccine status, while 3 had one dose and 7 had 2 doses of measles vaccine. Notably, 5 of 11 internationally imported measles cases were adults, and all were unvaccinated or had unknown vaccine status. During the first month of the outbreak, 26 of the 51 (51%) cases were attributable to adults; of the 26, 15 (58%) were in adults and 11 (42%) were in children who acquired infection from adults (Figure 3). Conclusion The majority of measles cases occurred in unvaccinated children emphasizing the importance of ongoing and focused efforts on pediatric vaccination. However, measles cases in unvaccinated adults played an important role in both importations and disease transmission early in the outbreak. These data strongly support current recommendations of 1 dose of measles, mumps, rubella vaccine (MMR) for most adults and 2 doses of MMR for adults traveling internationally and at high-risk such as those in outbreak areas, as determined by local/state public health. Disclosures Kirsten St. George, MAppSc, PhD, Akonni Biosystems (Other Financial or Material Support), ThermoFisher (Grant/Research Support), Zeptometrix (Other Financial or Material Support, royalty generating collaborative agreement). .

Stability, Bifurcation and Optimal Control Analysis of a Malaria Model in a Periodic Environment

2018 ◽  
Vol 19 (6) ◽  
pp. 627-642 ◽  
Author(s):  
Prabir Panja ◽  
Shyamal Kumar Mondal ◽  
Joydev Chattopadhyay
Keyword(s):  
Optimal Control ◽  
Disease Transmission ◽  
Existence Condition ◽  
Infected Mosquito ◽  
Transmission Model ◽  
Control Analysis ◽  
Periodic Environment ◽  
Vector Population ◽  
Autonomous Case ◽  
Disease Transmission Model

AbstractIn this paper, a malaria disease transmission model has been developed. Here, the disease transmission rates from mosquito to human as well as human to mosquito and death rate of infected mosquito have been constituted by two variabilities: one is periodicity with respect to time and another is based on some control parameters. Also, total vector population is divided into two subpopulations such as susceptible mosquito and infected mosquito as well as the total human population is divided into three subpopulations such as susceptible human, infected human and recovered human. The biologically feasible equilibria and their stability properties have been discussed. Again, the existence condition of the disease has been illustrated theoretically and numerically. Hopf-bifurcation analysis has been done numerically for autonomous case of our proposed model with respect to some important parameters. At last, a optimal control problem is formulated and solved using Pontryagin’s principle. In numerical simulations, different possible combination of controls have been illustrated including the comparisons of their effectiveness.

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