COVID-19 is a severe acute respiratory syndrome caused by the Coronavirus-2 virus(SARS-CoV-2).The virus spreads from one to another through droplets from an infected person,and sometimes these droplets can contaminate...COVID-19 is a severe acute respiratory syndrome caused by the Coronavirus-2 virus(SARS-CoV-2).The virus spreads from one to another through droplets from an infected person,and sometimes these droplets can contaminate surfaces that may be another infection pathway.In this study,we developed a COVID-19 model based on data and observations in Thailand.The country has strictly distributed masks,vaccination,and social distancing measures to control the disease.Hence,we have classified the susceptible individuals into two classes:one who follows the measures and another who does not take the control guidelines seriously.We conduct epidemic and endemic analyses and represent the threshold dynamics characterized by the basic reproduction number.We have examined the parameter values used in our model using the mean general interval(GI).From the calculation,the value is 5.5 days which is the optimal value of the COVID-19 model.Besides,we have formulated an optimal control problem to seek guidelines maintaining the spread of COVID-19.Our simulations suggest that high-risk groups with no precaution to prevent the disease(maybe due to lack of budgets or equipment)are crucial to getting vaccinated to reduce the number of infections.The results also indicate that preventive measures are the keys to controlling the disease.展开更多
The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies...The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies to implement public health control mea- sures are worthwhile to be investigated. In this paper, we aim to better understand the effects of HI states of vibrios from the environment and from human contacts that cause cholera outbreaks. We also present and analyze our cholera mathematical model with vaccine incorporated. Equilibrium analysis is conducted in the case with constant control for both epidemic and endemic dynamics. Optimal control theory is applied to seek cost-effective solutions of time-dependent vaccination strategies against cholera outbreaks. Our results show that using vaccination during cholera outbreaks at the very beginning of the onset can reduce the number of infections significantly.展开更多
The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. However, guidelines for using vaccination during cholera outbreaks are still to be established...The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. However, guidelines for using vaccination during cholera outbreaks are still to be established, and it remains an open question as to how and when the vaccines should be deployed to best control ongoing cholera outbreaks. Here we formulate a new optimal control model to assess the value of cholera vaccines in epidemic settings and cost-effective optimal times to deploy a vaccine. Our results suggest that as long as the vaccine prices are sufficiently low, vaccination should always start from or immediately after the onset of a cholera outbreak.展开更多
Rabies is a fatal contagious disease but preventable.It is a major public health problem in developing countries.Most of the rabies deaths around the world are caused by dog bites.If a person does not receive appropri...Rabies is a fatal contagious disease but preventable.It is a major public health problem in developing countries.Most of the rabies deaths around the world are caused by dog bites.If a person does not receive appropriate treatment after being exploded to rabies,the virus can damage the brain resulting in death.Since most of the deaths due to the transmission from dogs to humans,therefore,in this study,we will formulate a mathematical model that describes the dynamics of rabies virus transmission between dogs and humans.Also,we conduct both epidemic and endemic analysis.Optimal control theory is applied to seek cost-effective solutions for time-dependent vaccination and culling strategies against rabies outbreaks.Our results show that using vaccination during rabies outbreaks at the very beginning of the onset and culling infected dogs can reduce the number of infections significantly.展开更多
Avian influenza, caused by influenza A viruses, has received worldwide attention over recent years. In this study, we formulate a mathematical model for avian influenza that includes human human transmission and incor...Avian influenza, caused by influenza A viruses, has received worldwide attention over recent years. In this study, we formulate a mathematical model for avian influenza that includes human human transmission and incorporates the effects of infection latency and treatments. We investigate the essential dynamics of the model through an equilibrium analysis. Meanwhile, we explore effective treatment strategies to control avian influenza outbreaks using optimal control theory. Our results show that strategically deployed medical treatments can significantly reduce the numbers of exposed and infection persons.展开更多
We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that...We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.展开更多
文摘COVID-19 is a severe acute respiratory syndrome caused by the Coronavirus-2 virus(SARS-CoV-2).The virus spreads from one to another through droplets from an infected person,and sometimes these droplets can contaminate surfaces that may be another infection pathway.In this study,we developed a COVID-19 model based on data and observations in Thailand.The country has strictly distributed masks,vaccination,and social distancing measures to control the disease.Hence,we have classified the susceptible individuals into two classes:one who follows the measures and another who does not take the control guidelines seriously.We conduct epidemic and endemic analyses and represent the threshold dynamics characterized by the basic reproduction number.We have examined the parameter values used in our model using the mean general interval(GI).From the calculation,the value is 5.5 days which is the optimal value of the COVID-19 model.Besides,we have formulated an optimal control problem to seek guidelines maintaining the spread of COVID-19.Our simulations suggest that high-risk groups with no precaution to prevent the disease(maybe due to lack of budgets or equipment)are crucial to getting vaccinated to reduce the number of infections.The results also indicate that preventive measures are the keys to controlling the disease.
文摘The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies to implement public health control mea- sures are worthwhile to be investigated. In this paper, we aim to better understand the effects of HI states of vibrios from the environment and from human contacts that cause cholera outbreaks. We also present and analyze our cholera mathematical model with vaccine incorporated. Equilibrium analysis is conducted in the case with constant control for both epidemic and endemic dynamics. Optimal control theory is applied to seek cost-effective solutions of time-dependent vaccination strategies against cholera outbreaks. Our results show that using vaccination during cholera outbreaks at the very beginning of the onset can reduce the number of infections significantly.
基金J. Wang acknowledges partial support from the National Science Foundation under Grant Nos. 0813691 and 1216936. Z. Mukandavire was supported by the UF Science for Life Program, an interdisciplinary program with support from the Howard Hughes Medical Institute. The authors would like to thank the anonymous referees for helpful comments.
文摘The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. However, guidelines for using vaccination during cholera outbreaks are still to be established, and it remains an open question as to how and when the vaccines should be deployed to best control ongoing cholera outbreaks. Here we formulate a new optimal control model to assess the value of cholera vaccines in epidemic settings and cost-effective optimal times to deploy a vaccine. Our results suggest that as long as the vaccine prices are sufficiently low, vaccination should always start from or immediately after the onset of a cholera outbreak.
文摘Rabies is a fatal contagious disease but preventable.It is a major public health problem in developing countries.Most of the rabies deaths around the world are caused by dog bites.If a person does not receive appropriate treatment after being exploded to rabies,the virus can damage the brain resulting in death.Since most of the deaths due to the transmission from dogs to humans,therefore,in this study,we will formulate a mathematical model that describes the dynamics of rabies virus transmission between dogs and humans.Also,we conduct both epidemic and endemic analysis.Optimal control theory is applied to seek cost-effective solutions for time-dependent vaccination and culling strategies against rabies outbreaks.Our results show that using vaccination during rabies outbreaks at the very beginning of the onset and culling infected dogs can reduce the number of infections significantly.
基金Acknowledgments Chairat Modnak thanks Thailand Research Fund （No. TRG5780041）, Faculty of Science at Naresuan University, and Naresuan University Research Fund for partial support of this work. Jin Wang was partially supported by the National Science Foundation under Grant No. 1412826.
文摘Avian influenza, caused by influenza A viruses, has received worldwide attention over recent years. In this study, we formulate a mathematical model for avian influenza that includes human human transmission and incorporates the effects of infection latency and treatments. We investigate the essential dynamics of the model through an equilibrium analysis. Meanwhile, we explore effective treatment strategies to control avian influenza outbreaks using optimal control theory. Our results show that strategically deployed medical treatments can significantly reduce the numbers of exposed and infection persons.
文摘We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.
