La Gloria, Mexico: The possible origins and response of a worldwide H1N1 flu pandemic in 2009

2013 ◽  
Vol 8 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Sahar Hashmi, MD
Keyword(s):  
Extended Period ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Telephone Interviews ◽  
Mexican Community ◽  
Nonpharmaceutical Interventions ◽  
Google Search ◽  
The Relationship ◽  
H1n1 Flu

This article traces the spread and route of the H1N1 pandemic in 2009 from its possible origin in La Gloria to Mexico City. A lack of health control measures or nonpharmaceutical interventions (NPIs) in La Gloria accounts for the unprecedented high basic reproductive number (R0) in that town and a higher incidence of H1N1 flu in Mexico City.We analyzed data collected from Mexican news articles, the Healthmaps dataset, the Google search engine, and telephone interviews with Mexican community physicians and residents. Our article uses a simple Susceptible Infected and Recovered model based on the data collected, to show the relationship between the disease curve and the implementation of NPI use. As a result of this study, we conclude that, with strict government measures to control the disease over an extended period of time, it is possible that many hundreds or even thousands of lives might be saved in the future.

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 Different Transmission Dynamics of Coronavirus Disease 2019 (COVID-19) and Influenza Suggest the Relative Efficiency of Isolation/Quarantine and Social Distancing Against COVID-19 in China

2020 ◽  
Author(s):  
Hao Lei ◽  
Xifeng Wu ◽  
Xiao Wang ◽  
Modi Xu ◽  
Yu Xie ◽  
...  
Keyword(s):  
Relative Efficiency ◽  
Seasonal Influenza ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Social Distancing ◽  
Relative Age ◽  
Age Dependent ◽  
The Mean ◽  
Age Structured ◽  
Nonpharmaceutical Interventions

Abstract Background Nonpharmaceutical interventions (NPIs) against coronavirus disease 2019 (COVID-19) are vital to reducing transmission risks. However, the relative efficiency of social distancing against COVID-19 remains controversial, since social distancing and isolation/quarantine were implemented almost at the same time in China. Methods In this study, surveillance data of COVID-19 and seasonal influenza in 2018–2020 were used to quantify the relative efficiency of NPIs against COVID-19 in China, since isolation/quarantine was not used for the influenza epidemics. Given that the relative age-dependent susceptibility to influenza and COVID-19 may vary, an age-structured susceptible/infected/recovered model was built to explore the efficiency of social distancing against COVID-19 under different population susceptibility scenarios. Results The mean effective reproductive number, Rt, of COVID-19 before NPIs was 2.12 (95% confidence interval [CI], 2.02–2.21). By 11 March 2020, the overall reduction in Rt of COVID-19 was 66.1% (95% CI, 60.1–71.2%). In the epidemiological year 2019–20, influenza transmissibility was reduced by 34.6% (95% CI, 31.3–38.2%) compared with transmissibility in epidemiological year 2018–19. Under the observed contact pattern changes in China, social distancing had similar efficiency against COVID-19 in 3 different scenarios. By assuming the same efficiency of social distancing against seasonal influenza and COVID-19 transmission, isolation/quarantine and social distancing could lead to 48.1% (95% CI, 35.4–58.1%) and 34.6% (95% CI, 31.3–38.2%) reductions of the transmissibility of COVID-19, respectively. Conclusions Though isolation/quarantine is more effective than social distancing, given that the typical basic reproductive number of COVID-19 is 2–3, isolation/quarantine alone could not contain the COVID-19 pandemic effectively in China.

scholarly journals Estimating the risk on outbreak spreading of 2019-nCoV in China using transportation data

2020 ◽  
Author(s):  
Hsiang-Yu Yuan ◽  
M. Pear Hossain ◽  
Mesfin Tsegaye ◽  
Xiaolin Zhu ◽  
Pengfei Jia ◽  
...  
Keyword(s):  
Arrival Time ◽  
Critical Time ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Mathematical Framework ◽  
Cumulative Number ◽  
Border Control ◽  
Imported Cases ◽  
Novel Virus

AbstractA novel corona virus (2019-nCoV) was identified in Wuhan, China and has been causing an unprecedented outbreak in China. The spread of this novel virus can eventually become an international emergency. During the early outbreak phase in Wuhan, one of the most important public health tasks is to prevent the spread of the virus to other cities. Therefore, full-scale border control measures to prevent the spread of virus have been discussed in many nearby countries. At the same time, lockdown in Wuhan cityu (border control from leaving out) has been imposed. The challenge is that many people have traveled from Wuhan to other cities before the border control. Thus, it is difficult to forecast the number of imported cases at different cities and estimate their risk on outbreak emergence.Here, we have developed a mathematical framework incorporating city-to-city connections to calculate the number of imported cases of the novel virus from an outbreak source, and the cumulative number of secondary cases generated by the imported cases. We used this number to estimate the arrival time of outbreak emergence using air travel frequency data from Wuhan to other cities, collected from the International Air Transport Association database. In addition, a meta-population compartmental model was built based on a classical SIR approach to simulate outbreaks at different cities.We consider the scenarios under three basic reproductive number (R0) settings using the best knowledge of the current findings, from high (2.92), mild (1.68), to a much lower numbers (1.4). The mean arrival time of outbreak spreading has been determined. Under the high R0, the critical time is 17.9 days after December 31, 2019 for outbreak spreading. Under the low R0, the critical time is between day 26.2 to day 35 after December 31, 2019. To make an extra 30 days gain, under the low R0 (1.4), the control measures have to reduce 87% of the connections between the source and target cities. Under the higher R0 (2.92), the effect on reducing the chance of outbreak emergence is generally low until the border control measure was enhanced to reduce more than 95% of the connections.

scholarly journals Application of a Mathematical Model in Determining the Spread of the Rabies Virus: Simulation Study

10.2196/18627 ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. e18627
Author(s):  
Yihao Huang ◽  
Mingtao Li
Keyword(s):  
Mathematical Model ◽  
Rabies Virus ◽  
Control Measures ◽  
Transmission Mode ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Stable Range ◽  
Rabies Control ◽  
Number Of Patients ◽  
Acute Infectious Disease

Background Rabies is an acute infectious disease of the central nervous system caused by the rabies virus. The mortality rate of rabies is almost 100%. For some countries with poor sanitation, the spread of rabies among dogs is very serious. Objective The objective of this paper was to study the ecological transmission mode of rabies to make theoretical contributions to the suppression of rabies in China. Methods A mathematical model of the transmission mode of rabies was constructed using relevant data from the literature and officially published figures in China. Using this model, we fitted the data of the number of patients with rabies and predicted the future number of patients with rabies. In addition, we studied the effectiveness of different rabies suppression measures. Results The results of the study indicated that the number of people infected with rabies will rise in the first stage, and then decrease. The model forecasted that in about 10 years, the number of rabies cases will be controlled within a relatively stable range. According to the prediction results of the model reported in this paper, the number of rabies cases will eventually plateau at approximately 500 people every year. Relatively effective rabies suppression measures include controlling the birth rate of domestic and wild dogs as well as increasing the level of rabies immunity in domestic dogs. Conclusions The basic reproductive number of rabies in China is still greater than 1. That is, China currently has insufficient measures to control rabies. The research on the transmission mode of rabies and control measures in this paper can provide theoretical support for rabies control in China.

scholarly journals Dynamical analysis of the spread of African swine fever with the live pig price in China

2021 ◽  
Vol 18 (6) ◽  
pp. 8123-8148
Author(s):  
Yihao Huang ◽  
◽  
Jing Li ◽  
Juan Zhang ◽  
Zhen Jin ◽  
...  
Keyword(s):  
Supply And Demand ◽  
African Swine Fever ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Dynamical Analysis ◽  
Critical Conditions ◽  
Reproductive Number ◽  
Price Function ◽  
The Government ◽  
The Impact

<abstract><p>Pork makes up the highest proportion of household expenditure on meat in China and supply and demand have been basically stable in the past decade. However, the catastrophic outbreak of African swine fever (ASF) in August 2018 disrupted the balance and reduced the national herd by half within six months. The consequence was a gross lack of supply to the market and consumer demand was unable to be met. Accordingly, live pig prices rose sharply from 2019. In order to assess the influence of ASF on the price of the live pigs, we use a price function to characterize the relationship between price of the live pigs and the nation's pig stock, and then establish a time delay ASF epidemic dynamical model with the price function. By analyzing the dynamical behaviors of the model, we calculate the basic reproductive number, discuss the stability of equilibrium, and obtain the critical conditions for Hopf bifurcation. The model reasonableness is confirmed by carrying out data fitting and parameter estimation based on price data of the live pigs, the pig stock data and the outbreak data of ASF. By performing sensitivity analysis, we intuitively show the impact of ASF on the price of live pigs and the pig stocks, and assess the key factors affecting the outbreak of ASF. The conclusion is drawn that, with the control measures adopted by related government department in China, the basic reproductive number ($ R_0 = 0.6005 $) means that the ASF epidemic has been controlled. Moreover, the price of the live pig increases linearly with $ R_0 $, while the effect of the number of infected pigs on the subsequent price is non-linear related. Our findings suggest that society and the government should pay more attention to the prevention of animal disease epidemics.</p></abstract>

scholarly journals The Novel Coronavirus, 2019-nCoV, is Highly Contagious and More Infectious Than Initially Estimated

2020 ◽  
Author(s):  
Steven Sanche ◽  
Yen Ting Lin ◽  
Chonggang Xu ◽  
Ethan Romero-Severson ◽  
Nick Hengartner ◽  
...  
Keyword(s):  
Case Reports ◽  
Individual Case ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Contact Tracing ◽  
Reproductive Number ◽  
The Novel ◽  
Transmission Potential ◽  
Novel Coronavirus ◽  
Strong Control

AbstractThe novel coronavirus (2019-nCoV) is a recently emerged human pathogen that has spread widely since January 2020. Initially, the basic reproductive number, R0, was estimated to be 2.2 to 2.7. Here we provide a new estimate of this quantity. We collected extensive individual case reports and estimated key epidemiology parameters, including the incubation period. Integrating these estimates and high-resolution real-time human travel and infection data with mathematical models, we estimated that the number of infected individuals during early epidemic double every 2.4 days, and the R0 value is likely to be between 4.7 and 6.6. We further show that quarantine and contact tracing of symptomatic individuals alone may not be effective and early, strong control measures are needed to stop transmission of the virus.One-sentence summaryBy collecting and analyzing spatiotemporal data, we estimated the transmission potential for 2019-nCoV.

scholarly journals Modeling and Analysis of the Spread of Malware with the Influence of User Awareness

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qingyi Zhu ◽  
Xuhang Luo ◽  
Yuhang Liu
Keyword(s):  
Propagation Model ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Asymptotically Stable ◽  
Sis Model ◽  
Globally Asymptotically Stable ◽  
Modeling And Analysis ◽  
Malware Propagation ◽  
User Awareness

By incorporating the security awareness of computer users into the susceptible-infected-susceptible (SIS) model, this study proposes a new malware propagation model, named the SID model, where D compartment denotes the group of nodes with user awareness. Through qualitative analysis, the basic reproductive number R 0 is given. Furthermore, it is proved that the virus-free equilibrium is globally asymptotically stable if R 0 is less than one, whereas the viral equilibrium is globally asymptotically stable if R 0 is greater than one. Then, some numerical examples are given to demonstrate the analytical results. Finally, we put forward some efficient control measures according to the theoretical and experimental analysis.

scholarly journals Optimal Control and Cost Effectiveness Analysis of SIRS Malaria Disease Model with Temperature Variability Factor

2021 ◽  
Vol 53 (1) ◽  
pp. 134-163
Author(s):  
Temesgen Duressa Keno ◽  
Oluwole Daniel Makinde ◽  
Legesse Lemecha Obsu
Keyword(s):  
Optimal Control ◽  
Cost Effectiveness ◽  
Initial Conditions ◽  
Control Strategies ◽  
Disease Model ◽  
Temperature Variability ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Bed Nets ◽  
Reproductive Number

In this study, we proposed and analyzed the optimal control and cost-effectiveness strategies for malaria epidemics model with impact of temperature variability. Temperature variability strongly determines the transmission of malaria. Firstly, we proved that all solutions of the model are positive and bounded within a certain set with initial conditions. Using the next-generation matrix method, the basic reproductive number at the present malaria-free equilibrium point was computed. The local stability and global stability of the malaria-free equilibrium were depicted applying the Jacobian matrix and Lyapunov function respectively when the basic reproductive number is smaller than one. However, the positive endemic equilibrium occurs when the basic reproductive number is greater than unity. A sensitivity analysis of the parameters was conducted; the model showed forward and backward bifurcation. Secondly, using Pontryagin’s maximum principle, optimal control interventions for malaria disease reduction are described involving three control measures, namely use of insecticide-treated bed nets, treatment of infected humans using anti-malarial drugs, and indoor residual insecticide spraying. An analysis of cost-effectiveness was also conducted. Finally, based on the simulation of different control strategies, the combination of treatment of infected humans and insecticide spraying was proved to be the most efficient and least costly strategy to eradicate the disease.

scholarly journals Characteristics and evaluation of the effectiveness of monitoring and control measures for the first 69 Patients with COVID-19 from 18 January 2020 to 2 March in Wuxi, China

2020 ◽  
Author(s):  
Ping Shi ◽  
Yumeng Gao ◽  
Yuan Shen ◽  
Enping Chen ◽  
Hai Chen ◽  
...  
Keyword(s):  
Risk Factors ◽  
Close Contact ◽  
Virus Detection ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Monitoring And Control ◽  
Infected People ◽  
Novel Coronavirus ◽  
And Control

Abstract Background: The novel coronavirus disease 2019(COVID-19) outbreak and has caused has caused 82,830 confirmed cases and 4,633 deaths in China by 26 April 2020. We analyzed data on 69 infections in Wuxi to describe the epidemiologic characteristics and evaluate the control measures.Methods: The demographic characteristics, exposure history, and illness timelines of COVID-19 cases in Wuxi were collected.Results: Among the 69 positive infections with COVID-19, mild and normal types accounted for 75.36% (52/69), adolescents and children are mainly mild and asymptomatic. The basic reproductive number was estimated to be 1.12 (95% CI, 0.71 to 1.69). The mean incubation period was estimated to be 4.77 days (95% CI, 3.61 to 5.94), with a mean serial interval of 6.31 days (95%CI, 5.12 to 7.50). We also found that age (RR=1.57, 95%CI: 1.11-2.21) and fever (RR=4.09, 95%CI: 1.10-15.19) were risk factors for COVID-19 disease severity.Conclusions: The incidence of COVID-19 in Wuxi has turned into a lower level, suggesting that the early prevention and control measures have achieved effectiveness. The community transmission can be effectively prevented through isolation and virus detection of all the people who were exposed together and close contact with the infected people. Aging and fever are risk factors for clinical outcome, which might be useful for preventing severe transition.

scholarly journals Epidemiological Characteristics of COVID-19 under Government-mandated Control Measures in Inner Mongolia, China

2020 ◽  
Author(s):  
Sha Du ◽  
Haiwen Lu ◽  
Yuenan Su ◽  
Shufeng Bi ◽  
Jing Wu ◽  
...  
Keyword(s):  
Incubation Period ◽  
Inner Mongolia ◽  
Close Contact ◽  
Scientific Information ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Fatality Rate ◽  
Duration Of Hospitalization ◽  
Epidemiological Characteristics

Abstract BackgroundThere were 75 local confirmed cases during the COVID-19 epidemic followed by an outbreak of Wuhan in Inner Mongolia. The aims of our study were to provide reference to control measures of COVID-19 and scientific information for supporting government decision-making for serious infectious disease, in remote regions with relatively insufficient medical resources like Inner Mongolia.MethodsThe data published by Internet were summarized in order to describe the epidemiological and clinical characteristics of patients with COVID-19. The basic reproductive number (R 0 ), incubation period, time from illness onset to confirmed and the duration of hospitalization were analyzed. The composition of imported and local secondary cases and the mild/common and severe/critical cases among different ages, genders and major clinical symptoms were compared.ResultsIn 2020, from January 23 to February 19 (less than 1 month), 75 local cases of COVID-19 were confirmed in Inner Mongolia. Among them, the median age was 45 years old (34.0, 57.0), and 61.1% were male and 33 were imported (44.0%). 29 (38.7%) were detected through close contact tracking, more than 80.0% were mild/common cases. The fatality rate was 1.3% and the basic reproductive number (R 0 ) was estimated to be 2.3. The median incubation period was 8.5 days (6.0~12.0) and the maximum incubation period reached 28 days. There was a statistically difference in the incubation period between imported and local secondary cases ( P <0.001). The duration of hospitalization of patients with incubation period <8.5 days was higher than that of patients with incubation period ≥8.5 days (30.0 vs. 24.0 days).ConclusionIn Inner Mongolia, an early and mandatory control strategy by government associated with the rapidly reduced incidence of COVID-19, by which the epidemic growth was controlled completely. And the fatality rate of COVID-19 was relatively low.

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