This paper surnmarizes the historical experiences in venereal disease control in China during the 1950s.Venereal diseases had been all but eliminated in the whole country till 1964. However, along with the implementat...This paper surnmarizes the historical experiences in venereal disease control in China during the 1950s.Venereal diseases had been all but eliminated in the whole country till 1964. However, along with the implementation of open-door policy and economic reform in the 1980s, the social environment was changed to a great extent in this country. Sexually transmitted diseases (STDs) were reintreduced in the Chinese mainland and new foci of infection established themselves in some cities. During the recent 8 years the national STD case-reporting and sentinel surveillance systems have been set up. The results of surveillance show that the annual incidence of STD has been on the increase. The existing factors associated with the increasing incidence of STD mainly are ; population movement , increasing affiuence in a part of population,the availability of multiple sexual partners (including the prostitution)and asymptomatic STD increased.Finally, the strategies for STD control are discussed in detail.展开更多
A model which incorporates some of the basic epidemiological features of the co- dynamics of malaria and tuberculosis （TB） is formulated and the effectiveness of current intervention strategies of these two diseases...A model which incorporates some of the basic epidemiological features of the co- dynamics of malaria and tuberculosis （TB） is formulated and the effectiveness of current intervention strategies of these two diseases is analyzed. The malaria-only and TB-only models are considered first. Global stability disease-free steady states of the two sub- models does not hold due to the co-existence of stable disease-free with stable endemic equilibria, a phenomenon known as backward bifurcation. The dynamics of the dual malari^TB model with intervention strategies are also analyzed. Numerical simulations of the malaria-TB model are carried out to determine whether the two diseases can co- exist. Lastly, sensitivity analysis on key parameters that drive the disease dynamics is performed in order to identify their relative importance to disease transmission.展开更多
Predator prey model with harvesting is well studied. The role of disease in such system has a great importance and cannot be ignored. In this study we have considered a predator prey model with disease circulating in ...Predator prey model with harvesting is well studied. The role of disease in such system has a great importance and cannot be ignored. In this study we have considered a predator prey model with disease circulating in the predator population only and we have also considered harvesting in the prey and in the susceptible predator. We have studied the local stability, Hopf bifurcation of the model system around the equilibria. We have derived the ecological and the disease basic reproduction numbers and we have observed its importance in the community structure of the model system and in controlling disease propagation in the predator population. We have paid attention to chaotic dynamics for increasing the force of infection in the predator. Chaotic population dynamics can exhibit irregular fluctuations and violent oscillations with extremely small or large population abundances. In this study main objective is to show the role of harvesting in controlling chaotic dynamics. It is observed that reasonable harvesting on the prey and the susceptible predator prevents chaotic dynamics.展开更多
文摘This paper surnmarizes the historical experiences in venereal disease control in China during the 1950s.Venereal diseases had been all but eliminated in the whole country till 1964. However, along with the implementation of open-door policy and economic reform in the 1980s, the social environment was changed to a great extent in this country. Sexually transmitted diseases (STDs) were reintreduced in the Chinese mainland and new foci of infection established themselves in some cities. During the recent 8 years the national STD case-reporting and sentinel surveillance systems have been set up. The results of surveillance show that the annual incidence of STD has been on the increase. The existing factors associated with the increasing incidence of STD mainly are ; population movement , increasing affiuence in a part of population,the availability of multiple sexual partners (including the prostitution)and asymptomatic STD increased.Finally, the strategies for STD control are discussed in detail.
文摘A model which incorporates some of the basic epidemiological features of the co- dynamics of malaria and tuberculosis （TB） is formulated and the effectiveness of current intervention strategies of these two diseases is analyzed. The malaria-only and TB-only models are considered first. Global stability disease-free steady states of the two sub- models does not hold due to the co-existence of stable disease-free with stable endemic equilibria, a phenomenon known as backward bifurcation. The dynamics of the dual malari^TB model with intervention strategies are also analyzed. Numerical simulations of the malaria-TB model are carried out to determine whether the two diseases can co- exist. Lastly, sensitivity analysis on key parameters that drive the disease dynamics is performed in order to identify their relative importance to disease transmission.
文摘Predator prey model with harvesting is well studied. The role of disease in such system has a great importance and cannot be ignored. In this study we have considered a predator prey model with disease circulating in the predator population only and we have also considered harvesting in the prey and in the susceptible predator. We have studied the local stability, Hopf bifurcation of the model system around the equilibria. We have derived the ecological and the disease basic reproduction numbers and we have observed its importance in the community structure of the model system and in controlling disease propagation in the predator population. We have paid attention to chaotic dynamics for increasing the force of infection in the predator. Chaotic population dynamics can exhibit irregular fluctuations and violent oscillations with extremely small or large population abundances. In this study main objective is to show the role of harvesting in controlling chaotic dynamics. It is observed that reasonable harvesting on the prey and the susceptible predator prevents chaotic dynamics.
