The Effect Of Biodiversity On Transmission Of West Nile Virus

West Nile virus disease is an infectious disease that has occurred in Europe and North America in recent years.Mosquitoes spread the virus and it pose a threat to the health of people and animals.According to the biological background and transmission of WNV disease,some suitable mathematical models are established and analyzed simply.The effects of biodiversity and Wolbachia on the prevalence of disease are explored by using numerical simulation and sensitivity analysis.The effects of host and mosquito control measures are assessed further.The primarily contents of this dissertation are listed as follows:1.A vector-host epidemic model is investigated which contain multiple populations and biting preference.By using the method of the next generation matrix,the basic reproduction number is derived which determines the local stability of the disease free equilibrium.The existence and conditions of equilibria are discussed based on appropriate assumptions and simplified model.Then the theory of the sensitivity analysis is applied to the model which shows that the mosquito host biting preference on birds.and mosquito control are the most important parameters.In order to investigate the effect of biodiversity and mosquito control on the transmission dynamics of disease,the numerical simulations are also performed to study the important issue.Our results suggest that the infection peak and the risk of disease outbreak can be reduced by recruiting more animals species which have greater biting preference,increasing the mortality of infectious birds or improving the efficiency of mosquito control.2.An epidemic model with mosquito growth stages and Wolbachia is studied.In this paper,the existence and condition of equilibria is discussed in the two cases with Wolbachia or not.The effect of Wolbachia on avian infection of WNV is simulated in different environments by numerical simulation.The results show that when K is low,Wolbachia technology can control the spread of disease effectively;when K is higher,the introduction of Wolbachia can slow the outbreak of disease,but it will increase the peak value of infection.The correlation between the parameters and R0 or equilibrium are detected by PRCC sensitivity analysis.The results show that the bite rate,mortality,infection of mosquito and the recruitment rate or WNV-induced death rate of birds are important for the WNV disease.