scholarly journals Early Spatiotemporal Patterns and Population Characteristics of the COVID-19 Pandemic in Southeast Asia

Healthcare ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1220
Author(s):  
Mingjian Zhu ◽  
Jirapat Kleepbua ◽  
Zhou Guan ◽  
Sien Ping Chew ◽  
Joanna Weihui Tan ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Population Characteristics ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Country Level ◽  
Disease Patterns ◽  
Geographical Variations ◽  
Health Authorities ◽  
Efficient Resource ◽  
Exponential Regression Model

This observational study aims to investigate the early disease patterns of coronavirus disease 2019 (COVID-19) in Southeast Asia, consequently providing historical experience for further interventions. Data were extracted from official websites of the WHO and health authorities of relevant countries. A total of 1346 confirmed cases of COVID-19, with 217 recoveries and 18 deaths, were reported in Southeast Asia as of 16 March 2020. The basic reproductive number (R0) of COVID-19 in the region was estimated as 2.51 (95% CI:2.31 to 2.73), and there were significant geographical variations at the subregional level. Early transmission dynamics were examined with an exponential regression model: y = 0.30e0.13x (p < 0.01, R2 = 0.96), which could help predict short-term incidence. Country-level disease burden was positively correlated with Human Development Index (r = 0.86, p < 0.01). A potential early shift in spatial diffusion patterns and a spatiotemporal cluster occurring in Malaysia and Singapore were detected. Demographic analyses of 925 confirmed cases indicated a median age of 44 years and a sex ratio (male/female) of 1.25. Age may play a significant role in both susceptibilities and outcomes. The COVID-19 situation in Southeast Asia is challenging and unevenly geographically distributed. Hence, enhanced real-time surveillance and more efficient resource allocation are urgently needed.

scholarly journals Variation in SARS-CoV-2 free-living survival and environmental transmission can modulate the intensity of COVID-19 outbreaks

2020 ◽  
Author(s):  
C. Brandon Ogbunugafor ◽  
Miles Miller-Dickson ◽  
Victor A. Meszaros ◽  
Lourdes M. Gomez ◽  
Anarina L. Murillo ◽  
...  
Keyword(s):  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Disease Dynamics ◽  
Free Living ◽  
Environmental Transmission ◽  
Country Level ◽  
History Of ◽  
Virus Survival ◽  
Case Data

ABSTRACTCOVID-19 has circled the globe, rapidly expanding into a pandemic within a matter of weeks. While early studies revealed important features of SARS-CoV-2 transmission, the role of variation in free-living virus survival in modulating the dynamics of outbreaks remains unclear and controversial. Using an empirically determined understanding of the natural history of SARS-CoV-2 infection and detailed, country-level case data, we elucidate how variation in free-living virus survival influences key features of COVID-19 epidemics. Our findings suggest that environmental transmission can have a subtle, yet significant influence on COVID-19’s basic reproductive number () and other key signatures of outbreak intensity. Summarizing, we propose that variation in environmental transmission may explain some observed differences in disease dynamics from setting to setting, and can inform public health interventions.

scholarly journals ESTIMATION OF THE VALUE OF THE COVID-19 BASIC REPRODUCTIVE NUMBER AND THE EFFECT OF ANTI-EPIDEMIC MEASURES AND “SEASONAL FACTOR” ON THIS VALUE

2021 ◽  
Vol 18 (38) ◽  
pp. 149-163
Author(s):  
Andrey GERASIMOV ◽  
Irina SEMENYCHEVA ◽  
Olga BELAIA ◽  
Elena VOLCHKOVA ◽  
Andrey GOROBCHENKO
Keyword(s):  
Accurate Method ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Reproduction Rate ◽  
Infected People ◽  
Noticeable Increase ◽  
A Value ◽  
Health Authorities ◽  
Seasonal Factors ◽  
Seasonal Factor

Background: The emergence of COVID-19 has led to increased attention to mathematical models of epidemiology, one of the main parameters of which is the basic reproductive number R0. Its value determines both the dynamics of the incidence and the level of anti-epidemic measures. Therefore, it is desirable to have a fairly accurate method for assessing R0 for each day. Aim: Develop a methodology for determining the R0 value for COVID-19, taking into account a reasonably rapid and significant change in its value over time. Methods: a method for calculating reproduction number R0 was proposed for assessing COVID-19 R0, taking into account the change in the contagiousness of the infected people during the infectious process. Results and Discussion: In Russia in June-August 2020, the reproduction rate was slightly less 1, but in September R0 began to grow, exceeded 1, which was caused a noticeable increase in the incidence. During June in Brazil, R0 stabilized at a value of 1. The activity of transmission of the pathogen is influenced by seasonal changes in the reproduction rate R0 and the level of community immune status. Based on the assessment of the dynamics of the incidence of other pneumonia, it was found that the change of R0 during the year is about 10%, with a minimum in summer. Conclusions: while maintaining the current activity of anti-epidemic measures due to seasonal factors of the activity of the transmission mechanism and accumulation of the immune individuals in the coming months, the situation in the Russian Federation will worsen with an increase in the incidence doubled within six months, and in Brazil in six months — improve with a decrease in the incidence ten times. However, the dynamics of the incidence will be determined primarily by the work of the administration and health authorities and the conscientiousness of citizens.

scholarly journals The epidemiology and transmissibility of Zika virus in Girardot and San Andres island, Colombia, September 2015 to January 2016

2016 ◽  
Vol 21 (28) ◽  
Author(s):  
Diana Patricia Rojas ◽  
Natalie E Dean ◽  
Yang Yang ◽  
Eben Kenah ◽  
Juliana Quintero ◽  
...  
Keyword(s):  
Zika Virus ◽  
Virus Disease ◽  
Age Groups ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Incidence Data ◽  
Health Authorities ◽  
Rapid Spread ◽  
Polymerase Chain ◽  
San Andres

Transmission of Zika virus (ZIKV) was first detected in Colombia in September 2015. As of April 2016, Colombia had reported over 65,000 cases of Zika virus disease (ZVD). We analysed daily surveillance data of ZVD cases reported to the health authorities of San Andres and Girardot, Colombia, between September 2015 and January 2016. ZVD was laboratory-confirmed by reverse transcription-polymerase chain reaction (RT-PCR) in the serum of acute cases within five days of symptom onset. We use daily incidence data to estimate the basic reproductive number (R0) in each population. We identified 928 and 1,936 reported ZVD cases from San Andres and Girardot, respectively. The overall attack rate for reported ZVD was 12.13 cases per 1,000 residents of San Andres and 18.43 cases per 1,000 residents of Girardot. Attack rates were significantly higher in females in both municipalities (p < 0.001). Cases occurred in all age groups with highest rates in 20 to 49 year-olds. The estimated R0 for the Zika outbreak was 1.41 (95% confidence interval (CI): 1.15–1.74) in San Andres and 4.61 (95% CI: 4.11–5.16) in Girardot. Transmission of ZIKV is ongoing in the Americas. The estimated R0 from Colombia supports the observed rapid spread.

scholarly journals Dynamics analysis of an online gambling spreading model on scale-free networks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Yu Kong ◽  
Tao Li ◽  
Yuanmei Wang ◽  
Xinming Cheng ◽  
He Wang ◽  
...  
Keyword(s):  
Network Topology ◽  
Negative Impact ◽  
Online Gambling ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Scale Free ◽  
Spreading Model ◽  
Spreading Dynamics ◽  
Scale Free Networks ◽  
Gambling Policy

AbstractNowadays, online gambling has a great negative impact on the society. In order to study the effect of people’s psychological factors, anti-gambling policy, and social network topology on online gambling dynamics, a new SHGD (susceptible–hesitator–gambler–disclaimer) online gambling spreading model is proposed on scale-free networks. The spreading dynamics of online gambling is studied. The basic reproductive number $R_{0}$ R 0 is got and analyzed. The basic reproductive number $R_{0}$ R 0 is related to anti-gambling policy and the network topology. Then, gambling-free equilibrium $E_{0}$ E 0 and gambling-prevailing equilibrium $E_{ +} $ E + are obtained. The global stability of $E_{0}$ E 0 is analyzed. The global attractivity of $E_{ +} $ E + and the persistence of online gambling phenomenon are studied. Finally, the theoretical results are verified by some simulations.

scholarly journals Effects of social distancing on the spreading of COVID-19 inferred from mobile phone data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamid Khataee ◽  
Istvan Scheuring ◽  
Andras Czirok ◽  
Zoltan Neufeld
Keyword(s):  
Mobile Phone ◽  
Basic Reproductive Number ◽  
Mobile Phone Data ◽  
Reproductive Number ◽  
Expansion Phase ◽  
Social Distancing ◽  
Exponential Expansion ◽  
Total Death ◽  
Mobility Reduction ◽  
Epidemiological Parameters

AbstractA better understanding of how the COVID-19 pandemic responds to social distancing efforts is required for the control of future outbreaks and to calibrate partial lock-downs. We present quantitative relationships between key parameters characterizing the COVID-19 epidemiology and social distancing efforts of nine selected European countries. Epidemiological parameters were extracted from the number of daily deaths data, while mitigation efforts are estimated from mobile phone tracking data. The decrease of the basic reproductive number ($$R_0$$ R 0 ) as well as the duration of the initial exponential expansion phase of the epidemic strongly correlates with the magnitude of mobility reduction. Utilizing these relationships we decipher the relative impact of the timing and the extent of social distancing on the total death burden of the pandemic.

scholarly journals Huanglongbing Model under the Control Strategy of Discontinuous Removal of Infected Trees

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1164
Author(s):  
Weiwei Ling ◽  
Pinxia Wu ◽  
Xiumei Li ◽  
Liangjin Xie
Keyword(s):  
Infectious Disease ◽  
Global Stability ◽  
Control Strategy ◽  
Theoretical Basis ◽  
Dynamic Properties ◽  
Transmission Mechanism ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Vector Borne ◽  
Citrus Trees

By using differential equations with discontinuous right-hand sides, a dynamic model for vector-borne infectious disease under the discontinuous removal of infected trees was established after understanding the transmission mechanism of Huanglongbing (HLB) disease in citrus trees. Through calculation, the basic reproductive number of the model can be attained and the properties of the model are discussed. On this basis, the existence and global stability of the calculated equilibria are verified. Moreover, it was found that different I0 in the control strategy cannot change the dynamic properties of HLB disease. However, the lower the value of I0, the fewer HLB-infected citrus trees, which provides a theoretical basis for controlling HLB disease and reducing expenditure.

scholarly journals Effect of specific non-pharmaceutical intervention policies on SARS-CoV-2 transmission in the counties of the United States

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bingyi Yang ◽  
Angkana T. Huang ◽  
Bernardo Garcia-Carreras ◽  
William E. Hart ◽  
Andrea Staid ◽  
...  
Keyword(s):  
United States ◽  
Home Visiting ◽  
Leisure Activities ◽  
The United States ◽  
Causal Effects ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
County Level ◽  
Metapopulation Model ◽  
Pharmaceutical Interventions

AbstractNon-pharmaceutical interventions (NPIs) remain the only widely available tool for controlling the ongoing SARS-CoV-2 pandemic. We estimated weekly values of the effective basic reproductive number (Reff) using a mechanistic metapopulation model and associated these with county-level characteristics and NPIs in the United States (US). Interventions that included school and leisure activities closure and nursing home visiting bans were all associated with a median Reff below 1 when combined with either stay at home orders (median Reff 0.97, 95% confidence interval (CI) 0.58–1.39) or face masks (median Reff 0.97, 95% CI 0.58–1.39). While direct causal effects of interventions remain unclear, our results suggest that relaxation of some NPIs will need to be counterbalanced by continuation and/or implementation of others.

scholarly journals Gestational Diabetes Mellitus in Southeast Asia: A Scoping Review

2021 ◽  
Vol 18 (3) ◽  
pp. 1272
Author(s):  
Thubasni Kunasegaran ◽  
Vinod R. M. T. Balasubramaniam ◽  
Valliammai Jayanthi Thirunavuk Arasoo ◽  
Uma Devi Palanisamy ◽  
Amutha Ramadas
Keyword(s):  
Diabetes Mellitus ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Southeast Asia ◽  
Scoping Review ◽  
Economic Status ◽  
Lifestyle Changes ◽  
Population Characteristics ◽  
Research Trend ◽  
Lifestyle Modifications

A rapid increase in the prevalence of gestational diabetes mellitus (GDM) has been associated with various factors such as urbanization, lifestyle changes, adverse hyperglycemic intrauterine environment, and the resulting epigenetic changes. Despite this, the burden of GDM has not been well-assessed in Southeast Asia. We comprehensively reviewed published Southeast Asian studies to identify the current research trend in GDM in this region. Joanna Briggs Institute’s methodology was used to guide the scoping review. The synthesis of literature findings demonstrates almost comparable clinical evidence in terms of risk factors and complications, challenges presented in diagnosing GDM, and its disease management, given the similarities of the underlying population characteristics in Southeast Asia. Evidence suggests that a large proportion of GDM risk in women may be preventable by lifestyle modifications. However, the GDM burden across countries is expected to rise, given the heterogeneity in screening approaches and diagnostic criteria, mainly influenced by economic status. There is an urgent need for concerted efforts by government and nongovernmental sectors to implement national programs to prevent, manage, and monitor the disease.

scholarly journals Viral Dynamics of Acute HIV-1 Infection

1999 ◽  
Vol 190 (6) ◽  
pp. 841-850 ◽  
Author(s):  
Susan J. Little ◽  
Angela R. McLean ◽  
Celsa A. Spina ◽  
Douglas D. Richman ◽  
Diane V. Havlir
Keyword(s):  
Antiretroviral Therapy ◽  
Hiv Infection ◽  
Doubling Time ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Target Cells ◽  
Viral Dynamics ◽  
Acute Hiv Infection ◽  
Acute Hiv ◽  
The Mean

Viral dynamics were intensively investigated in eight patients with acute HIV infection to define the earliest rates of change in plasma HIV RNA before and after the start of antiretroviral therapy. We report the first estimates of the basic reproductive number (R0), the number of cells infected by the progeny of an infected cell during its lifetime when target cells are not depleted. The mean initial viral doubling time was 10 h, and the peak of viremia occurred 21 d after reported HIV exposure. The spontaneous rate of decline (α) was highly variable among individuals. The phase 1 viral decay rate (δI = 0.3/day) in subjects initiating potent antiretroviral therapy during acute HIV infection was similar to estimates from treated subjects with chronic HIV infection. The doubling time in two subjects who discontinued antiretroviral therapy was almost five times slower than during acute infection. The mean basic reproductive number (R0) of 19.3 during the logarithmic growth phase of primary HIV infection suggested that a vaccine or postexposure prophylaxis of at least 95% efficacy would be needed to extinguish productive viral infection in the absence of drug resistance or viral latency. These measurements provide a basis for comparison of vaccine and other strategies and support the validity of the simian immunodeficiency virus macaque model of acute HIV infection.

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