Dynamic Modeling And Control Measures For The H5 Subtype Of Avian Influenza Virus

The widespread prevalence of H5 subtype avian influenza(AI)virus in poultry not only causes huge losses to the poultry farming industry,but also poses a serious threat to human health.In China,breeding density of poultry is large and AI virus spreads rapidly,especially in domestic land fowl.And a wide range of poultry are invaded by H5 subtype AI virus.So,the internal transmission mechanism of the epidemic is complex and hardly understandable.In order to effectively control the spread of the epidemic,the establishment of a targeted mathematical model can accurately describe the transmission mode of the H5 subtype AI virus.Theoretically,by studying the dynamics of the model,we can give the propagation threshold and explore the intrinsic propagation mechanism.In terms of application,through sensitivity analysis of the model,we can evaluate the effect of prevention and control measures and propose effective control measures for the spread of H5 subtype AI virus.In view of the spread of highly pathogenic H5 avian influenza in China,the following preliminary studies were conducted:1.Not only consider the infection of poultry breeding farm and sales markets to human,but also consider the effect of staff of breeding industry on the infection of poultry breeding farm and sales markets.This paper establishes a dynamic model about the transmission of H5N1 AI between farms in China.Firstly,we used stability theory to analyze the existence of the equilibrium point and the local stability of the disease-free equilibrium point of the model.Furthermore,we calculate the basic reproduction number 0 of H5N1 AI virus transmission in China by numerical method in combination with the culturing structure of poultry,poultry breeding farm and sales markets and the infection situation of poultry in China.In addition,we carry on sensitivity analysis of the basic reproduction number 0 by numerical simulation to evaluate the effect of prevention and control measures.2.Considering that different bird populations play different roles in the transmission of H5 subtype AI virus.This paper takes wild waterfowl,domestic waterfowl and domestic land fowl as research objects,establishes the transmission dynamics model of H5 subtype AI in different populations in China to excavate the internal transmission mechanism and assess the role of different kinds of poultry in the prevalence of H5 subtype AI virus.We use the least squares method to fit reported infected poultry data in Chinese mainland and Xizang,respectively,to confirm the reasonability of model.By applying risk factor assessment of model,it is concluded that for whole Chinese mainland,the new recruitment quantity of domestic waterfowl and the direct transmission coefficient of domestic poultry to domestic poultry have a larger effect on the spread of the epidemic.Compared with whole country,the control the transmission coefficient of Environment 1 is more important.In addition,the feeding pattern of domestic waterfowl plays a key role in the spread of the disease among all kinds of poultry.