Analyzing Of The Transmission Risks And Control Strategy Of The Zika Virus

Since the outbreak of Zika virus in Micronesia in 2007,it has spread over 65 countries and regions in the South Pacific and America,and the virus has become a major public health problem worldwide.Because more and more people pay attention to the connection between the pregnant women and the fetus malformation with the virus,it is particularly important to analyze the risk of spreading the virus among people and the effectiveness of the control strategy.Therefore,based on the number of cumulative reported cases infected by Zika virus from August 27,2016 to September 12,2016 in Singapore,we aim to develop mathematical and statistical methods to address the spread risk and effective con-trol measures in Singapore.In particular,a model describing the sex transmission between human and human,and a model describing the mosquito vector transmis-sion have been proposed in this thesis.Further,the unknown parameters have been estimated by employing least square and MCMC methods,which allows us to fit the number of cumulative reported cases.The main results reveal that the models developed here can be used to depict the transmission of Zika virus in Singapore.In order to better study the risk of the Zika virus transmission and to explore the effectiveness of the control measures,in the third chapter we employ the next generation matrix method to get the analytical formula of the basic reproduction number R0,which can be estimated by using the parameter values in the second chapter.Moreover,the 95%confidence interval of R0 is also obtained,which allows us to investigate the sensitivity of control measures.Thus,by using sensitivity analysis methods we address the effects of key param-eters related to the disease control on the number of cumulative reported cases In the fourth chapter.The main results reveal that the parameters including the rate from the latent class to infected class,the transmission rate between human,the transmission rate from mosquitoes to humans,the transmission rate from humans to mosquitoes,and the initial values are most important for disease transmission.Consequently,we discuss how to design the optimal control measures to mitigate the spread of the Zika virus.In a word,the dynamic models for Zika virus transmission were established and developed,the unknown parameters and the basic reproduction number were estimated by the real data,and the sensitivity of the cumulative number of reported cases to the parameters is analyzed.The main results reveal that the disease control department should strengthen the number of quarantine and quarantine rate,and isolation rate so as to reduce the contact between the patients and local residents;The public health department should strengthen environmental management,clean water and improve the quality of environmental hygiene so as to reduce the number of mosquito vector and human contact with mosquito vector;Limiting the number of local tourists and reducing population mobility.Those multiple control measures can reduce the number of cumulative cases,reduce the spread risk of Zika virus,and achieve the purpose of disease control.