| Hepatitis B is a common infectious disease caused by hepatitis B virus,which is seriously harmful to human health.The burden of chronic hepatitis B prevention is serious in China.From 2013 to 2016,the number of newly infected people of hepatitis B every year is about 0.95 million,and from 2017 to 2019,the number of newly infected people every year remains at 1 millon.This shows that the incidence of hepatitis B is still growing.According to the epidemic situation of hepatitis B,the state has continuously improved the implementation of a series of vaccination programs and other policies to control hepatitis B.In this paper,we analyze the data of hepatitis B cases in different provinces,establish a time-delayed dynamic model to describe the hepatitis B epidemic and put forward some prevention and control strategies.The research structure of this paper is as follows:The first chapter is the introduction,which firstly introduces the background of hepatitis B research,including the etiology,epidemiology,prevalence and existing prevention and control measures of hepatitis B.Secondly,it introduces the research status of hepatitis B transmission at home and abroad,which provides reference for the research of this paper.The consideration factors and the idea of model building in this paper are put forward,indicating the main research content of this paper.The second chapter is the introduction of the hepatitis B time-delayed dynamic model.Considering the incubation period,psychological inhibition factor,vaccine,limited medical resources and horizontal transmission,an SIRS model is proposed to describe hepatitis B transmission dynamics.The existence of the endemic equilibrium,existence and stability of the disease-free equilibrium and endemic equilibrium are discussed.The direction and stability of Hopf bifurcation and the existence of Bogdanov-Takens bifurcation produced by the system are also discussed.The third chapter is the data fitting method and results.Firstly,the data fitting method and parameter estimation process are introduced detailedly.Secondly,according to the features of periodic outbreak,aperiodic outbreak and periodic outbreak turns to an aperiodic outbreak of hepatitis B in different areas of China,we use our model to fit the actual hepatitis B monthly cases from Jiangxi,Zhejiang province and Beijing,the basic reproduction numbers that we estimated are 1.7712、1.4805 and1.4132 respectively.The fourth chapter is the discussion.The sensitivity of the basic reproduction number is analyzed and the different factors,non-drug control,treatment and vaccine,which influence the epidemic of hepatitis B are discussed.The basic reproduction number of different hepatitis B data is compared and analyzed.We conclude that reducing contact,increasing treatment rate,strengthening vaccination and revaccinating can effectively prevent and control the prevalence of hepatitis B.The fifth chapter is the conclusion,which shows the whole research content of this paper,summarizes the research results,and points out the shortcomings of the article research and the direction of the follow-up research. |
