scholarly journals The Modelling of Hand, Foot, and Mouth Disease in Contaminated Environments in Bangkok, Thailand

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Sudarat Chadsuthi ◽  
Surapa Wichapeng
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Direct Transmission ◽  
Free Living ◽  
Indirect Transmission ◽  
Foot And Mouth ◽  
Asymptomatic Individuals ◽  
The Basic Reproduction Number

Hand, foot, and mouth disease (HFMD) has spread widely in a continuing endemic in Thailand. There are no specific vaccines or antiviral treatments available that specifically target HFMD. Indirect transmission via free-living viruses from the environment may influence HFMD infections because the virus can survive for long periods in the environment. In this study, a new mathematical model is proposed to investigate the effect of indirect transmission from contaminated environments and the impact of asymptomatic individuals. By fitting our model to reported data on hospitalized individuals of HFMD endemic in Bangkok, Thailand, 2016, the basic reproduction number was estimated as 1.441, which suggests that the disease will remain under current conditions. Numerical simulations show that the direct transmission from asymptomatic individuals and indirect transmission via free-living viruses are important factors which contribute to new HFMD infections. Sensitivity analysis indicates that the basic reproduction number is sensitive to the transmission rate of asymptomatic and symptomatic subgroups and indirect transmission. Our findings suggest that cleaning the environment frequently and healthcare precautions which include the reduction of direct transmission rates should be promoted as effective control strategies for preventing the HFMD spread.

scholarly journals Hand, Foot, and Mouth Disease in Thailand: A Comprehensive Modelling of Epidemic Dynamics

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Suraj Verma ◽  
M. A. Razzaque ◽  
U. Sangtongdee ◽  
C. Arpnikanondt ◽  
B. Tassaneetrithep ◽  
...  
Keyword(s):  
Basic Reproduction Number ◽  
Clustering Algorithm ◽  
Reproduction Number ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Seasonal Effect ◽  
Epidemic Dynamics ◽  
District Hospitals ◽  
Foot And Mouth ◽  
The Basic Reproduction Number

Hand, foot, and mouth disease (HFMD) is a highly contagious disease with several outbreaks in Asian-Pacific countries, including Thailand. With such epidemic characteristics and potential economic impact, HFMD is a significant public health issue in Thailand. Generally, contagious/infectious diseases’ transmission dynamics vary across geolocations due to different socioeconomic situations, demography, and lifestyles. Hence, a nationwide comprehensive model of the disease’s epidemic dynamics can provide information to understand better and predict a potential outbreak of this disease and efficiently and effectively manage its impact. However, there is no nationwide and comprehensive (i.e., the inclusion of reinfections in the model) model of HFDM dynamics for Thailand. This paper has endeavoured to promote nationwide comprehensive modelling of HFMD’s epidemic dynamics and comprehend the reinfection cases. We have formulated the SEIRS epidemiological model with dynamic vitals, including reinfections, to explore this disease’s prevalence. We also introduced periodic seasonality to reproduce the seasonal effect. The pattern of spread of this disease is uneven across the provinces in Thailand, so we used K -means clustering algorithm to cluster those provinces into three groups (i.e., highly, moderately, and least affected levels). We also analysed health records collected from district hospitals, which suggest significant reinfection cases. For example, we found that 11% (approximately) of infectious patients return for repeat treatment within the study period. We also performed sensitivity analysis which indicates that the basic reproduction number ( R 0 ) is sensitive to the rate of transmission ( β ) and the rate at which infected people recover ( γ ). By fitting the model with HFMD confirmed data for the provinces in each cluster, the basic reproduction number ( R 0 ) was estimated to be 2.643, 1.91, and 3.246 which are greater than 1. Based on this high R 0 , this study recommends that this disease will persist in the coming years under identical cultural and environmental conditions.

scholarly journals Basic Reproduction Number of Enterovirus 71 Coxsackievirus A16 and A6: Evidence from Outbreaks of Hand, Foot and Mouth Disease in China between 2011 and 2018

2020 ◽  
Author(s):  
Zhong Zhang ◽  
Yang Liu ◽  
Fengfeng Liu ◽  
Minrui Ren ◽  
Taoran Nie ◽  
...  
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Mainland China ◽  
Enterovirus 71 ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Initial Growth ◽  
Coxsackievirus A16 ◽  
Foot And Mouth ◽  
Common Serotypes

Abstract Background Enterovirus 71 (EV-A71), Coxsackievirus A16 (CV-A16) and Coxsackievirus A6 (CV-A6) are common serotypes causing hand, foot, and mouth disease (HFMD). Analyses on the basic reproduction number (R0) of common pathogens causing HFMD are limited and there are no related studies using field data from outbreaks in mainland China. Methods We estimated the pathogen-specific basic reproduction number based on laboratory-confirmed HFMD outbreaks (clusters of ≥10 HFMD cases) reported to the national surveillance system between 2011 and 2018. The reproduction numbers were calculated using a mathematical model and the cumulative cases during the initial growth periods. Results This study included 539 outbreaks, of which 198 were caused by EV-A71, 316 by CV-A16, and 25 by CV-A6. All 10417 cases involved were children. Assuming the outbreaks occurred in closed systems and the incubation period is 5 days, the median R0s of EV-A71, CV-A16, and CV-A6 were 5.06 [2.81, 10.20], 4.84 [3.00, 9.00] and 5.94 [3.27, 10.00] (Median [IQR]). After adjusting for seroprevalences, the R0s for EV-A71, CV-A16 (optimistic and conservative scenarios), and CV-A6 were 12.60 [IQR: 7.35, 25.40], 9.29 [IQR: 6.01, 19.20], 15.50 [IQR: 9.77, 30.40], and 25.80 [IQR: 14.20, 43.50], respectively. We did not observe changes in the R0s of EV-A71 after vaccine licensure (p-value = 0.67). Conclusions HFMD is highly transmissible when caused by the three most common serotypes. In mainland China, it primarily affects young children. Although a vaccine became available in 2016, we have not yet observed any related changes in the disease dynamics.

Basic reproduction number of coxsackievirus type A6 and A16 and enterovirus 71: estimates from outbreaks of hand, foot and mouth disease in Singapore, a tropical city-state

2015 ◽  
Vol 144 (5) ◽  
pp. 1028-1034 ◽  
Author(s):  
C. T. K. LIM ◽  
L. JIANG ◽  
S. MA ◽  
L. JAMES ◽  
L. W. ANG
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Enterovirus 71 ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Control Measures ◽  
Initial Growth ◽  
Cumulative Number ◽  
Coxsackievirus A6 ◽  
Foot And Mouth

SUMMARYCoxsackievirus A6 (CV-A6), coxsackievirus A16 (CV-A16) and enterovirus 71 (EV-A71) were the major enteroviruses causing nationwide hand, foot and mouth disease (HFMD) epidemics in Singapore in the last decade. We estimated the basic reproduction number (R0) of these enteroviruses to obtain a better understanding of their transmission dynamics. We merged records of cases from HFMD outbreaks reported between 2007 and 2012 with laboratory results from virological surveillance. R0 was estimated based on the cumulative number of reported cases in the initial growth phase of each outbreak associated with the particular enterovirus type. A total of 33 HFMD outbreaks were selected based on the inclusion criteria specified for our study, of which five were associated with CV-A6, 13 with CV-A16, and 15 with EV-A71. The median R0 was estimated to be 5·04 [interquartile range (IQR) 3·57–5·16] for CV-A6, 2·42 (IQR 1·85–3·36) for CV-A16, and 3·50 (IQR 2·36–4·53) for EV-A71. R0 was not significantly associated with number of infected children (P = 0·86), number of exposed children (P = 0·94), and duration of the outbreak (P = 0·05). These enterovirus-specific R0 estimates will be helpful in providing insights into the potential growth of future HFMD epidemics and outbreaks for timely implementation of disease control measures, together with disease dynamics such as severity of the cases.

scholarly journals COVID-19 disease transmission model considering direct and indirect transmission

2020 ◽  
Vol 202 ◽  
pp. 12008
Author(s):  
Dipo Aldila
Keyword(s):  
Mathematical Model ◽  
Basic Reproduction Number ◽  
Disease Transmission ◽  
Reproduction Number ◽  
Transmission Model ◽  
Indirect Transmission ◽  
Variation Of Parameters ◽  
The Media ◽  
Disease Transmission Model ◽  
The Basic Reproduction Number

A mathematical model for understanding the COVID-19 transmission mechanism proposed in this article considering two important factors: the path of transmission (direct-indirect) and human awareness. Mathematical model constructed using a four-dimensional ordinary differential equation. We find that the Covid-19 free state is locally asymptotically stable if the basic reproduction number is less than one, and unstable otherwise. Unique endemic states occur when the basic reproduction number is larger than one. From sensitivity analysis on the basic reproduction number, we find that the media campaign succeeds in suppressing the endemicity of COVID-19. Some numerical experiments conducted to show the dynamic of our model respect to the variation of parameters value.

scholarly journals Dynamics of a vector-borne model with direct transmission and age of infection.

2021 ◽  
Author(s):  
Necibe Tuncer ◽  
Sunil Giri
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Endemic Equilibrium ◽  
Asymptotically Stable ◽  
Direct Transmission ◽  
Globally Asymptotically Stable ◽  
Born Model ◽  
Age Of Infection ◽  
Vector Borne ◽  
The Basic Reproduction Number

In this paper we the study of dynamics of time since infection structured vector born model with the direct transmission. We use standard incidence term to model the new infections. We analyze the corresponding system of partial di erential equation and obtain an explicit formula for the basic reproduction number R0. The diseases-free equilibrium is locally and globally asymptotically stable whenever the basic reproduction number is less than one, R0 < 1. Endemic equilibrium exists and is locally asymptotically stable when R0 > 1. The disease will persist at the endemic equilibrium whenever the basic reproduction number is greater than one.

scholarly journals Virus–Host Interactions in Foot-and-Mouth Disease Virus Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Kangli Li ◽  
Congcong Wang ◽  
Fan Yang ◽  
Weijun Cao ◽  
Zixiang Zhu ◽  
...  
Keyword(s):  
Disease Virus ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Virus Infections ◽  
Host Interactions ◽  
Indirect Transmission ◽  
Antiviral Responses ◽  
Host Machine ◽  
Mouth Disease Virus ◽  
Foot And Mouth

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals, which has been regarded as a persistent challenge for the livestock industry in many countries. Foot-and-mouth disease virus (FMDV) is the etiological agent of FMD that can spread rapidly by direct and indirect transmission. FMDV is internalized into host cell by the interaction between FMDV capsid proteins and cellular receptors. When the virus invades into the cells, the host antiviral system is quickly activated to suppress the replication of the virus and remove the virus. To retain fitness and host adaptation, various viruses have evolved multiple elegant strategies to manipulate host machine and circumvent the host antiviral responses. Therefore, identification of virus-host interactions is critical for understanding the host defense against virus infections and the pathogenesis of the viral infectious diseases. This review elaborates on the virus-host interactions during FMDV infection to summarize the pathogenic mechanisms of FMD, and we hope it can provide insights for designing effective vaccines or drugs to prevent and control the spread of FMD and other diseases caused by picornaviruses.

Theoretical assessment of the impact of environmental contamination on the dynamical transmission of polio

2019 ◽  
Vol 12 (02) ◽  
pp. 1950012 ◽  
Author(s):  
C. Balde ◽  
M. Lam ◽  
A. Bah ◽  
S. Bowong ◽  
J. J. Tewa
Keyword(s):  
Basic Reproduction Number ◽  
Environmental Contamination ◽  
Reproduction Number ◽  
Control Strategies ◽  
Asymptotically Stable ◽  
Globally Asymptotically Stable ◽  
Indirect Transmission ◽  
Populations At Risk ◽  
The Impact ◽  
The Basic Reproduction Number

A mathematical model for the dynamical transmission of polio is considered, with the aim of investigating the impact of environment contamination. The model captures two infection pathways through both direct human-to-human transmission and indirect human-to-environment-to-human transmission by incorporating the environment as a transition and/or reservoir of viruses. We derive the basic reproduction number [Formula: see text]. We show that the disease free equilibrium is globally asymptotically stable (GAS) if [Formula: see text], while if [Formula: see text], there exists a unique endemic equilibrium which is locally asymptotically stable (LAS). Similar results hold for environmental contamination free sub-model (without the incorporation of the indirect transmission). At the endemic level, we show that the number of infected individuals for the model with the environmental-related contagion is greater than the corresponding number for the environmental contamination free sub-model. In conjunction with the inequality [Formula: see text], where [Formula: see text] is the basic reproduction number for the environmental contamination free sub-model, our finding suggests that the contaminated environment plays a detrimental role on the transmission dynamics of polio disease by increasing the endemic level and the severity of the outbreak. Therefore, it is natural to implement control strategies to reduce the severity of the disease by providing adequate hygienic living conditions, educate populations at risk to follow rigorously those basic hygienic rules in order to avoid adequate contacts with suspected contaminated objects. Further, we perform numerical simulations to support the theory.

scholarly journals Interaction analysis on transmissibility of main pathogens of hand, foot, and mouth disease in Xi’an: a modelling study

2019 ◽  
Author(s):  
Yao Bai ◽  
Kun Liu ◽  
Zhongjun Shao ◽  
Zhijun Chen ◽  
Tianmu Chen
Keyword(s):  
Disease Burden ◽  
Reproduction Number ◽  
Interaction Analysis ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Enterovirus A71 ◽  
Foot And Mouth ◽  
Xi’An City ◽  
High Disease Burden

Abstract Objectives: Hand, foot, and mouth disease (HFMD) has spread widely and led to high disease burden in many countries, but the interaction among the pathogens of the disease remains unclear. In this study, we aimed to analyze the interaction of the main pathogens of HFMD using a mathematical model. Method: A dataset on reported HFMD cases was collected in Xi’an City. A long-term etiological surveillance was conducted focusing on the pathogens of the disease including Enterovirus A71 (EV71), Coxsachievirus A16 (CoxA16), and other enteroviruses. A susceptible–infectious–recovered model was adopted to calculate the reproduction number during the ascending period of reported cases (defined as Rasc) and the descending period (defined as Rdes). Results: In Xi’an, Rasc and Rdes of HFMD was 1.39 (95% CI: 1.31 – 1.48) and 0.70 (95% CI: 0.65 – 0.74), respectively. CoxA16 and other enteroviruses interacted with each other and decreased the value of Rasc. However, Rdes of CoxA16 was increased by other enteroviruses directionally.However, during the reported cases decreasing period, interactions only occurred between EV71 and other enteroviruses and between CoxA16 and other enteroviruses. These interactions all decreased Rasc but increased Rdes of affected pathogens. Conclusions: The interaction of the pathogens exists in Xi’an City. The reproduction number of the affected pathogen is adjusted and verges to 1 by the interaction.

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