scholarly journals Modelling and Estimating the Transmissibility of COVID-19: Transmission Dynamics in Shaanxi Province of China as a Case Study

2020 ◽  
Author(s):  
Xu-Sheng Zhang ◽  
Wei Liu ◽  
Huan Xiong ◽  
Zhengji Chen
Keyword(s):  
Infectious Diseases ◽  
Emerging Infectious Diseases ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Shaanxi Province ◽  
Infectious Agents ◽  
Essential Information ◽  
Infected People ◽  
Strong Control ◽  
Local Transmission

Abstract To control and contain the outbreaks of emerging infectious diseases such as COVID-19, it is important to know how easy and fast they transmit among people. To explore the essential information of the novel infectious agents, people always confront an inverse problem: using (partially) observed numbers of infected people by time and region to dig up the underlying characteristics of unknown infectious agents. Epidemics armed with advanced statistical inference and mathematical theory has been developed to help reconstruct transmission dynamics processes and to estimate key features of infectious diseases. In this study we use COVID-19 outbreak in Shaanxi province as an example to illustrate how the infectious disease dynamics method can be used to help build the transmission process and to estimate the transmissibility of COVID-19. Three transmission dynamics models were proposed for this. By separating continuous importation from local transmission and treating imported cases as the source rather than results of local transmission, the basic reproduction number of COVID-19 in Shaanxi province was estimated in the range from 0.46 to 0.61, well below the critical value of 1.0. This indicates that COVID-19 cannot self-sustain in Shaanxi province and reflects the timely and strong control measures taken in Shaanxi province.

scholarly journals Taiwan’s Successful COVID-19 Mitigation and Containment Strategy: Achieving Quasi Population Immunity

2020 ◽  
pp. 1-4 ◽  
Author(s):  
Li-Chien Chien ◽  
Christian K. Beÿ ◽  
Kristi L. Koenig
Keyword(s):  
Public Health ◽  
Infectious Diseases ◽  
Health Management ◽  
Mainland China ◽  
Emerging Infectious Diseases ◽  
Contact Tracing ◽  
Population Immunity ◽  
Containment Strategy ◽  
Local Transmission ◽  
Pharmaceutical Interventions

ABSTRACT The authors describe Taiwan’s successful strategy in achieving control of coronavirus disease (COVID-19) without economic shutdown, despite the prediction that millions of infections would be imported from travelers returning from Chinese New Year celebrations in Mainland China in early 2020. As of September 2, 2020, Taiwan reports 489 cases, 7 deaths, and no locally acquired COVID-19 cases for the last 135 days (greater than 4 months) in its population of over 23.8 million people. Taiwan created quasi population immunity through the application of established public health principles. These non-pharmaceutical interventions, including public masking and social distancing, coupled with early and aggressive identification, isolation, and contact tracing to inhibit local transmission, represent a model for optimal public health management of COVID-19 and future emerging infectious diseases.

scholarly journals Analysis of Spatiotemporal Characteristics of Pandemic SARS Spread in Mainland China

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Chunxiang Cao ◽  
Wei Chen ◽  
Sheng Zheng ◽  
Jian Zhao ◽  
Jinfeng Wang ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Mainland China ◽  
Emerging Infectious Diseases ◽  
Epidemiological Data ◽  
Transmission Dynamics ◽  
Bayesian Maximum Entropy ◽  
Covariance Model ◽  
Spatial And Temporal Scales ◽  
Epidemiological Characteristics ◽  
Spatiotemporal Transmission

Severe acute respiratory syndrome (SARS) is one of the most severe emerging infectious diseases of the 21st century so far. SARS caused a pandemic that spread throughout mainland China for 7 months, infecting 5318 persons in 194 administrative regions. Using detailed mainland China epidemiological data, we study spatiotemporal aspects of this person-to-person contagious disease and simulate its spatiotemporal transmission dynamics via the Bayesian Maximum Entropy (BME) method. The BME reveals that SARS outbreaks show autocorrelation within certain spatial and temporal distances. We use BME to fit a theoretical covariance model that has a sine hole spatial component and exponential temporal component and obtain the weights of geographical and temporal autocorrelation factors. Using the covariance model, SARS dynamics were estimated and simulated under the most probable conditions. Our study suggests that SARS transmission varies in its epidemiological characteristics and SARS outbreak distributions exhibit palpable clusters on both spatial and temporal scales. In addition, the BME modelling demonstrates that SARS transmission features are affected by spatial heterogeneity, so we analyze potential causes. This may benefit epidemiological control of pandemic infectious diseases.

scholarly journals Spatiotemporal distribution of COVID-19 during the first 7 months of the epidemic in Vietnam

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Toshie Manabe ◽  
Dung Phan ◽  
Yasuhiro Nohara ◽  
Dan Kambayashi ◽  
Thang Huu Nguyen ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Phase 1 ◽  
Age Distribution ◽  
Emerging Infectious Diseases ◽  
Spatial Cluster ◽  
Spatiotemporal Distribution ◽  
Control Measures ◽  
World Health ◽  
Phase 2 ◽  
Epidemic Wave

Abstract Background Understanding the spatiotemporal distribution of emerging infectious diseases is crucial for implementation of control measures. In the first 7 months from the occurrence of COVID-19 pandemic, Vietnam has documented comparatively few cases of COVID-19. Understanding the spatiotemporal distribution of these cases may contribute to development of global countermeasures. Methods We assessed the spatiotemporal distribution of COVID-19 from 23 January to 31 July 2020 in Vietnam. Data were collected from reports of the World Health Organization, the Vietnam Ministry of Health, and related websites. Temporal distribution was assessed via the transmission classification (local or quarantined cases). Geographical distribution was assessed via the number of cases in each province along with their timelines. The most likely disease clusters with elevated incidence were assessed via calculation of the relative risk (RR). Results Among 544 observed cases of COVID-19, the median age was 35 years, 54.8% were men, and 50.9% were diagnosed during quarantine. During the observation period, there were four phases: Phase 1, COVID-19 cases occurred sporadically in January and February 2020; Phase 2, an epidemic wave occurred from the 1st week of March to the middle of April (Wave 1); Phase 3, only quarantining cases were involved; and Phase 4, a second epidemic wave began on July 25th, 2020 (Wave 2). A spatial cluster in Phase 1 was detected in Vinh Phuc Province (RR, 38.052). In Phase 2, primary spatial clusters were identified in the areas of Hanoi and Ha Nam Province (RR, 6.357). In Phase 4, a spatial cluster was detected in Da Nang, a popular coastal tourist destination (RR, 70.401). Conclusions Spatial disease clustering of COVID-19 in Vietnam was associated with large cities, tourist destinations, people’s mobility, and the occurrence of nosocomial infections. Past experiences with outbreaks of emerging infectious diseases led to quick implementation of governmental countermeasures against COVID-19 and a general acceptance of these measures by the population. The behaviors of the population and the government, as well as the country’s age distribution, may have contributed to the low incidence and small number of severe COVID-19 cases.

scholarly journals Agent-Based Modeling for Super-Spreading Events: A Case Study of MERS-CoV Transmission Dynamics in the Republic of Korea

2018 ◽  
Vol 15 (11) ◽  
pp. 2369 ◽  
Author(s):  
Yunhwan Kim ◽  
Hohyung Ryu ◽  
Sunmi Lee
Keyword(s):  
Infectious Diseases ◽  
Transmission Rate ◽  
Emerging Infectious Diseases ◽  
Epidemiological Data ◽  
Agent Based Modeling ◽  
Transmission Dynamics ◽  
Republic Of Korea ◽  
Agent Based ◽  
The Republic ◽  
High Level

Super-spreading events have been observed in the transmission dynamics of many infectious diseases. The 2015 MERS-CoV outbreak in the Republic of Korea has also shown super-spreading events with a significantly high level of heterogeneity in generating secondary cases. It becomes critical to understand the mechanism for this high level of heterogeneity to develop effective intervention strategies and preventive plans for future emerging infectious diseases. In this regard, agent-based modeling is a useful tool for incorporating individual heterogeneity into the epidemic model. In the present work, a stochastic agent-based framework is developed in order to understand the underlying mechanism of heterogeneity. Clinical (i.e., an infectivity level) and social or environmental (i.e., a contact level) heterogeneity are modeled. These factors are incorporated in the transmission rate functions under assumptions that super-spreaders have stronger transmission and/or higher links. Our agent-based model has employed real MERS-CoV epidemic features based on the 2015 MERS-CoV epidemiological data. Monte Carlo simulations are carried out under various epidemic scenarios. Our findings highlight the roles of super-spreaders in a high level of heterogeneity, underscoring that the number of contacts combined with a higher level of infectivity are the most critical factors for substantial heterogeneity in generating secondary cases of the 2015 MERS-CoV transmission.

A SATURATED TREATMENT MODEL FOR THE TRANSMISSION DYNAMICS OF RABIES

2019 ◽  
Vol 4 (1) ◽  
pp. 201
Author(s):  
A A Ayoade ◽  
O J Peter ◽  
T A Ayoola ◽  
S Amadiegwu ◽  
A A Victor
Keyword(s):  
Incidence Rate ◽  
Nonlinear Differential Equations ◽  
Viral Disease ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Infectious Agents ◽  
Multiple Control ◽  
Saturated Incidence Rate ◽  
Saturated Incidence ◽  
Saturated Treatment

Rabies is a viral disease that claims about 59 000 lives globally every year. The ignorance of the fact that man can be a carrier of the disease makes every practical and theoretical approach towards the study of the disease a good development. In this work, a mathematical model is designed to incorporate a saturated incidence rate such that the incidence rate is saturated around the infectious agents. The model is studied qualitatively via stability theory of nonlinear differential equations to assess the effects of general awareness, constant vaccination and the saturated treatment on the transmission dynamics of rabies disease. The effective reproduction number is derived and the numerical simulation is carried out to verify the analytical results. It is discovered that while general awareness plays pivotal roles in averting rabies death, multiple control measures have the tendency of driving rabies to extinction.

scholarly journals Persistent infections support maintenance of a coronavirus in a population of Australian bats (Myotis macropus)

2017 ◽  
Vol 145 (10) ◽  
pp. 2053-2061 ◽  
Author(s):  
J. JEONG ◽  
C. S. SMITH ◽  
A. J. PEEL ◽  
R. K. PLOWRIGHT ◽  
D. H. KERLIN ◽  
...  
Keyword(s):  
Public Health ◽  
Data Analysis ◽  
Infectious Diseases ◽  
Epidemic Model ◽  
Emerging Infectious Diseases ◽  
Viral Transmission ◽  
Transmission Dynamics ◽  
Persistent Infections ◽  
Study Population ◽  
Reservoir Hosts

SUMMARYUnderstanding viral transmission dynamics within populations of reservoir hosts can facilitate greater knowledge of the spillover of emerging infectious diseases. While bat-borne viruses are of concern to public health, investigations into their dynamics have been limited by a lack of longitudinal data from individual bats. Here, we examine capture–mark–recapture (CMR) data from a species of Australian bat (Myotis macropus) infected with a putative novel Alphacoronavirus within a Bayesian framework. Then, we developed epidemic models to estimate the effect of persistently infectious individuals (which shed viruses for extensive periods) on the probability of viral maintenance within the study population. We found that the CMR data analysis supported grouping of infectious bats into persistently and transiently infectious bats. Maintenance of coronavirus within the study population was more likely in an epidemic model that included both persistently and transiently infectious bats, compared with the epidemic model with non-grouping of bats. These findings, using rare CMR data from longitudinal samples of individual bats, increase our understanding of transmission dynamics of bat viral infectious diseases.

scholarly journals Virus-Like Particles: Revolutionary Platforms for Developing Vaccines Against Emerging Infectious Diseases

2022 ◽  
Vol 12 ◽  
Author(s):  
Hasnat Tariq ◽  
Sannia Batool ◽  
Saaim Asif ◽  
Mohammad Ali ◽  
Bilal Haider Abbasi
Keyword(s):  
Infectious Diseases ◽  
Biomedical Engineering ◽  
Emerging Infectious Diseases ◽  
Infectious Agents ◽  
Expression Systems ◽  
Virus Like Particles ◽  
Potential Applicability ◽  
To Come ◽  
Conventional Vaccine ◽  
Insight Into

Virus-like particles (VLPs) are nanostructures that possess diverse applications in therapeutics, immunization, and diagnostics. With the recent advancements in biomedical engineering technologies, commercially available VLP-based vaccines are being extensively used to combat infectious diseases, whereas many more are in different stages of development in clinical studies. Because of their desired characteristics in terms of efficacy, safety, and diversity, VLP-based approaches might become more recurrent in the years to come. However, some production and fabrication challenges must be addressed before VLP-based approaches can be widely used in therapeutics. This review offers insight into the recent VLP-based vaccines development, with an emphasis on their characteristics, expression systems, and potential applicability as ideal candidates to combat emerging virulent pathogens. Finally, the potential of VLP-based vaccine as viable and efficient immunizing agents to induce immunity against virulent infectious agents, including, SARS-CoV-2 and protein nanoparticle-based vaccines has been elaborated. Thus, VLP vaccines may serve as an effective alternative to conventional vaccine strategies in combating emerging infectious diseases.

scholarly journals Exposure-history Type and Characteristics of SARS-CoV-2 Infected Patients in Wuhan（Epicenter） Neighboring Shaanxi Province of China

2020 ◽  
Author(s):  
Zhangqian Chen ◽  
Xiaoming Xu ◽  
Zhongshu Pu ◽  
Rui Yan ◽  
Jingwei Li ◽  
...  
Keyword(s):  
Control Measures ◽  
Shaanxi Province ◽  
Second Stage ◽  
Outbreak Period ◽  
Imported Cases ◽  
Exposure History ◽  
Surrounding Areas ◽  
Local Transmission

Abstract Background Since December 2019, an increasing number of SARS-CoV-2 infected pneumonia cases have been identified in Wuhan and its surrounding areas. As of March 2020 more than 150 countries, areas or territories have reported the infected cases of SARS-CoV-2 and still the infected number is rapidly increasing globally. Methods The whole outbreak period in Shaanxi Province (from Jan 23, 2020 to Feb 20, 2020) was split into two consecutive stages. Epidemiological feature like exposure-history type and characteristics of the confirmed SARS-CoV-2 infected patients in Shaanxi Province were analyzed. Results A total of 245 patients were confirmed with SARS-CoV-2 infection in Shaanxi Province, among whom 133 (54.29%) were male and 112 (45.71%) were female. The percentage of the imported cases dropped from 53.94% in earlier stage (Jan 23-Feb 5, 2020) to 16.25% in second stage (Feb 6-Feb 20, 2020) while that of cases with no definite exposure history and other types increased from 27.88–70.00%. Conclusions As control measures were taken in earlier stage much less cases were confirmed in second stage. Our study contributes to the understanding of SARS-CoV-2 epidemiology and helps evaluate the effectiveness of control measures on local transmission.

scholarly journals Towards the endgame and beyond: complexities and challenges for the elimination of infectious diseases

2013 ◽  
Vol 368 (1623) ◽  
pp. 20120137 ◽  
Author(s):  
Petra Klepac ◽  
C. Jessica E. Metcalf ◽  
Angela R. McLean ◽  
Katie Hampson
Keyword(s):  
Public Health ◽  
Infectious Diseases ◽  
Human Health ◽  
Control Measures ◽  
Theme Issue ◽  
Last Mile ◽  
Successful Control ◽  
Unanticipated Consequences ◽  
Low Levels ◽  
Local Transmission

Successful control measures have interrupted the local transmission of human infectious diseases such as measles, malaria and polio, and saved and improved billions of lives. Similarly, control efforts have massively reduced the incidence of many infectious diseases of animals, such as rabies and rinderpest, with positive benefits for human health and livelihoods across the globe. However, disease elimination has proven an elusive goal, with only one human and one animal pathogen globally eradicated. As elimination targets expand to regional and even global levels, hurdles may emerge within the endgame when infections are circulating at very low levels, turning the last mile of these public health marathons into the longest mile. In this theme issue, we bring together recurring challenges that emerge as we move towards elimination, highlighting the unanticipated consequences of particular ecologies and pathologies of infection, and approaches to their management.

scholarly journals Evolution and Epidemic Spread of SARS-CoV-2 in Colombia: A Year into the Pandemic

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 837
Author(s):  
Sergio Castañeda ◽  
Luz H. Patiño ◽  
Marina Muñoz ◽  
Nathalia Ballesteros ◽  
Enzo Guerrero-Araya ◽  
...  
Keyword(s):  
Incidence Rate ◽  
Epidemic Model ◽  
Disease Surveillance ◽  
Diagnostic Testing ◽  
Genomic Analysis ◽  
Health Impact ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Essential Information ◽  
Health Decision

Current efforts to understand the epidemiology, transmission dynamics and emergence of novel SARS-CoV-2 variants worldwide has enabled the scientific community to generate critical information aimed at implementing disease surveillance and control measures, as well as to reduce the social, economic and health impact of the pandemic. Herein, we applied an epidemic model coupled with genomic analysis to assess the SARS-CoV-2 transmission dynamics in Colombia. This epidemic model allowed to identify the geographical distribution, Rt dynamics and predict the course of the pandemic considering current implementation of countermeasures. The analysis of the incidence rate per 100,000 inhabitants carried out across different regions of Colombia allowed visualizing the changes in the geographic distribution of cases. The cumulative incidence during the timeframe March 2020 to March 2021 revealed that Bogotá (8063.0), Quindío (5482.71), Amazonas (5055.68), Antioquia (4922.35) and Tolima (4724.41) were the departments with the highest incidence rate. The highest median Rt during the first period evaluated was 2.13 and 1.09 in the second period; with this model, we identified improving opportunities in health decision making related to controlling the pandemic, diagnostic testing capacity, case registration and reporting, among others. Genomic analysis revealed 52 circulating SARS-CoV-2 lineages in Colombia detected from 774 genomes sequenced throughout the first year of the pandemic. The genomes grouped into four main clusters and exhibited 19 polymorphisms. Our results provide essential information on the spread of the pandemic countrywide despite implementation of early containment measures. In addition, we aim to provide deeper phylogenetic insights to better understand the evolution of SARS-CoV-2 in light of the latent emergence of novel variants and how these may potentially influence transmissibility and infectivity.

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