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 The effects of border control and quarantine measures on global spread of COVID-19

2020 ◽  
Author(s):  
M. Pear Hossain ◽  
Alvin Junus ◽  
Xiaolin Zhu ◽  
Pengfei Jia ◽  
Tzai-Hung Wen ◽  
...  
Keyword(s):  
Arrival Time ◽  
Control Measure ◽  
Control Measures ◽  
Rapid Expansion ◽  
Reproductive Number ◽  
Mathematical Framework ◽  
Border Control ◽  
Travel History ◽  
Global Spread ◽  
Imported Cases

AbstractThe rapid expansion of coronavirus (COVID-19) has been observed in many parts of the world. Many newly reported cases of this new coronavirus during early outbreak phases have been associated with travel history from an epidemic region (identified as imported cases). For those cases without travel history, the risk of wider spreads through community contact is even higher. However, most population models assume a homogeneous infected population without considering that the imported and secondary cases contracted by the imported cases can pose a different risk to community spread.We have developed an “easy-to-use” mathematical framework extending from a meta-population model embedding city-to-city connections to stratify the dynamics of transmission waves caused by imported, secondary, and others from an outbreak source region when control measures are considered. Using the dynamics of the secondary cases, we are able to determine the probability of community spread.Using the top 10 visiting cities from Wuhan in China as an example, we first demonstrated that the arrival time and the dynamics of the outbreaks at these cities can be successfully predicted under the reproductive number R0 = 2.92 and latent period τ = 5.2 days. Next, we showed that although control measures can gain extra 32.5 and 44.0 days in arrival time through a high intensive border control measure and a shorter time to quarantine under a low R0 (1.4), if the R0 is higher (2.92), only 10 extra days can be gained for each of the same measures. This suggests the importance of lowering the incidence at source regions together with infectious disease control measures in susceptible regions. The study allows us to assess the effects of border control and quarantine measures on the emergence and the global spread in a fully connected world using the dynamics of the secondary cases.

scholarly journals Risk Assessment of Novel Coronavirus COVID-19 Outbreaks Outside China

2020 ◽  
Vol 9 (2) ◽  
pp. 571 ◽  
Author(s):  
Péter Boldog ◽  
Tamás Tekeli ◽  
Zsolt Vizi ◽  
Attila Dénes ◽  
Ferenc A. Bartha ◽  
...  
Keyword(s):  
Control Measure ◽  
Mainland China ◽  
Destination Country ◽  
Control Measures ◽  
Cumulative Number ◽  
Travel Restrictions ◽  
Imported Cases ◽  
Major Outbreak ◽  
Novel Coronavirus ◽  
Local Reproduction

We developed a computational tool to assess the risks of novel coronavirus outbreaks outside of China. We estimate the dependence of the risk of a major outbreak in a country from imported cases on key parameters such as: (i) the evolution of the cumulative number of cases in mainland China outside the closed areas; (ii) the connectivity of the destination country with China, including baseline travel frequencies, the effect of travel restrictions, and the efficacy of entry screening at destination; and (iii) the efficacy of control measures in the destination country (expressed by the local reproduction number R loc ). We found that in countries with low connectivity to China but with relatively high R loc , the most beneficial control measure to reduce the risk of outbreaks is a further reduction in their importation number either by entry screening or travel restrictions. Countries with high connectivity but low R loc benefit the most from policies that further reduce R loc . Countries in the middle should consider a combination of such policies. Risk assessments were illustrated for selected groups of countries from America, Asia, and Europe. We investigated how their risks depend on those parameters, and how the risk is increasing in time as the number of cases in China is growing.

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 Epidemiology of the Zika virus outbreak in the Cabo Verde Islands, West Africa

2017 ◽  
Author(s):  
José Lourenço ◽  
Maria de Lourdes Monteiro ◽  
Tomás Valdez ◽  
Júlio Monteiro Rodrigues ◽  
Oliver G. Pybus ◽  
...  
Keyword(s):  
West Africa ◽  
Zika Virus ◽  
Attack Rate ◽  
Herd Immunity ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Mathematical Framework ◽  
Single Wave ◽  
Cabo Verde ◽  
Small Observation

AbstractIntroductionThe Zika virus (ZIKV) outbreak in the island nation of Cabo Verde was of unprecedented magnitude in Africa and the first to be associated with microcephaly in the continent.MethodsUsing a simple mathematical framework we present a first epidemiological assessment of attack and observation rates from 7,580 ZIKV notified cases and 18 microcephaly reports between July 2015 and May 2016.ResultsIn line with observations from the Americas and elsewhere, the single-wave Cabo Verdean ZIKV epidemic was characterized by a basic reproductive number of 1.85 (95% CI, 1.5 −2.2), with overall the attack rate of 51.1% (range 42.1 - 61.1) and observation rate of 2.7% (range 2.29 - 3.33).ConclusionCurrent herd-immunity may not be sufficient to prevent future small-to-medium epidemics in Cabo Verde. Together with a small observation rate, these results highlight the need for rapid and integrated epidemiological, molecular and genomic surveillance to tackle forthcoming outbreaks of ZIKV and other arboviruses.

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 Estimation of the Outbreak Severity and Evaluation of Epidemic Prevention Ability of COVID-19 by Province in China

2020 ◽  
Vol 110 (12) ◽  
pp. 1837-1843
Author(s):  
Yilei Ma ◽  
Xuehan Liu ◽  
Weiwei Tao ◽  
Yuchen Tian ◽  
Yanran Duan ◽  
...  
Keyword(s):  
Emergency Response ◽  
Disease Transmission ◽  
Initial Period ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Linear Mixed Effects Model ◽  
Linear Mixed Effects ◽  
Imported Cases ◽  
And Control ◽  
Case Data

Objectives. To compare the epidemic prevention ability of COVID-19 of each province in China and to evaluate the existing prevention and control capacity of each province. Methods. We established a quasi-Poisson linear mixed-effects model using the case data in cities outside Wuhan in Hubei Province, China. We adapted this model to estimate the number of potential cases in Wuhan and obtained epidemiological parameters. We estimated the initial number of cases in each province by using passenger flowrate data and constructed the extended susceptible–exposed–infectious–recovered model to predict the future disease transmission trends. Results. The estimated potential cases in Wuhan were about 3 times the reported cases. The basic reproductive number was 3.30 during the initial outbreak. Provinces with more estimated imported cases than reported cases were those in the surrounding provinces of Hubei, including Henan and Shaanxi. The regions where the number of reported cases was closer to the predicted value were most the developed areas, including Beijing and Shanghai. Conclusions. The number of confirmed cases in Wuhan was underestimated in the initial period of the outbreak. Provincial surveillance and emergency response capabilities vary across the country.

scholarly journals Analysis of Imported Cases of COVID-19 in Taiwan: A Nationwide Study

2020 ◽  
Vol 17 (9) ◽  
pp. 3311 ◽  
Author(s):  
Jui-Yao Liu ◽  
Tzeng-Ji Chen ◽  
Shinn-Jang Hwang
Keyword(s):  
Control Measures ◽  
Contact Tracing ◽  
Border Control ◽  
Symptom Presentation ◽  
Symptom Screening ◽  
Imported Cases ◽  
Infection Source ◽  
Community Transmission ◽  
Strict Enforcement ◽  
Novel Coronavirus

In the early stages of the 2019 novel coronavirus disease (COVID-19) pandemic, containment of disease importation from epidemic areas was essential for outbreak control. This study is based on publicly accessible data on confirmed COVID-19 cases in Taiwan extracted from the Taiwan Centers for Disease Control website. We analysed the characteristics, infection source, symptom presentation, and route of identification of the 321 imported cases that were identified from 21 January to 6 April 2020. They were mostly returned Taiwanese citizens who had travelled to one or more of 37 countries for tourism, business, work, or study. Half of these cases developed symptoms before arrival, most of the remainder developed symptoms 1–13 days (mean 4.0 days) after arrival, and 3.4% never developed symptoms. Three-quarters of the cases had respiratory symptoms, 44.9% had fever, 13.1% lost smell or taste, and 7.2% had diarrhoea. Body temperature and symptom screening at airports identified 32.7% of the cases. Of the remainder, 27.7% were identified during home quarantining, 16.2% were identified via contact tracing, and 23.4% were reported by hospitals. Under the strict enforcement of these measures, the incidence of locally acquired COVID-19 cases in Taiwan remains sporadic. In conclusion, proactive border control measures are effective for preventing community transmission of this disease.

scholarly journals Reduction of Human Mobility Matters during Early COVID-19 Outbreaks: Evidence from India, Japan and China

2021 ◽  
Vol 18 (6) ◽  
pp. 2826
Author(s):  
Zhehao Ren ◽  
Ruiyun Li ◽  
Tao Zhang ◽  
Bin Chen ◽  
Che Wang ◽  
...  
Keyword(s):  
Human Mobility ◽  
Critical Time ◽  
Reproductive Number ◽  
Time Varying ◽  
Virus Spread ◽  
Illness Onset ◽  
Global Pandemic ◽  
Imported Cases ◽  
Local Transmission ◽  
Japan And China

Mobility restrictions have been a heated topic during the global pandemic of coronavirus disease 2019 (COVID-19). However, multiple recent findings have verified its importance in blocking virus spread. Evidence on the association between mobility, cases imported from abroad and local medical resource supplies is limited. To reveal the association, this study quantified the importance of inter- and intra-country mobility in containing virus spread and avoiding hospitalizations during early stages of COVID-19 outbreaks in India, Japan, and China. We calculated the time-varying reproductive number (Rt) and duration from illness onset to diagnosis confirmation (Doc), to represent conditions of virus spread and hospital bed shortages, respectively. Results showed that inter-country mobility fluctuation could explain 80%, 35%, and 12% of the variance in imported cases and could prevent 20 million, 5 million, and 40 million imported cases in India, Japan and China, respectively. The critical time for screening and monitoring of imported cases is 2 weeks at minimum and 4 weeks at maximum, according to the time when the Pearson’s Rs between Rt and imported cases reaches a peak (>0.8). We also found that if local transmission is initiated, a 1% increase in intra-country mobility would result in 1430 (±501), 109 (±181), and 10 (±1) additional bed shortages, as estimated using the Doc in India, Japan, and China, respectively. Our findings provide vital reference for governments to tailor their pre-vaccination policies regarding mobility, especially during future epidemic waves of COVID-19 or similar severe epidemic outbreaks.

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>

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