Stability and Hopf bifurcation in a virus model with self-proliferation and delayed activation of immune cells.

A new mathematical model was proposed to study the effect of self-proliferation and delayed activation of immune cells in the process of virus infection. The global stability of the boundary equilibria was obtained by constructing appropriate Lyapunov functional. For positive equilibrium, the conditions of stability and Hopf bifurcation were obtained by taking the delay as the bifurcation parameter. Furthermore, the direction and stability of the Hopf bifurcation are derived by using the theory of normal form and center manifold. These results indicate that self-proliferation intensity can significantly affect the kinetics of viral infection, and the delayed activation of immune cells can induce periodic oscillation scenario. Along with the increase of delay time, numerical simulations give the corresponding bifurcation diagrams under different self-proliferation rates, and verify that there exists stability switch phenomenon under some conditions.

Evaluation of prevention and control interventions and its impact on the epidemic of coronavirus disease 2019 in Chongqing and Guizhou Provinces.

The outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still severe. In order to optimize the epidemic response strategy, it is urgent to evaluate the implemented prevention and control interventions (PCIs). Based on the reported data of Chongqing and Guizhou Provinces, the phased dynamic models of COVID-19 were constructed, the average intensity of the existing PCIs (from January 25 to March 2) was estimated in these two provinces. The results indicate that both provinces have carried out better control of the infected, but there are still differences in the intensity of control for people who need close observation. Especially in Chongqing, the estimated strength is significantly smaller than that in Guizhou. Furthermore, qualitative evaluations on the epidemic of COVID-19 under different PCIs scenarios suggest that containment strategy is still necessary to ensure the safety of resumption of work and school, and quarantining the city of Wuhan is an important and effective containment strategy to reduce the epidemic in other provinces.

Epidemics and underlying factors of multiple-peak pattern on hand, foot and mouth disease inWenzhou, China.

Background: Several outbreaks of severe hand-foot-mouth disease (HFMD) in East Asia and Southwest Asia in recent years have had a serious impact on the countries. However, the factors that contribute to annual multiple-peak pattern of HFMD outbreaks, and how and when do these factors play the decisive role in the HFMD transmission is still unclear. METHODS: Based on the surveillance data of HFMD between 1 January 2010 to 31 December 2015 in Wenzhou, China, the daily modelfree basic reproduction number and its annual average were first estimated by incorporating incubation and infection information, then the annual model-based basic reproduction number was computed by the proposed kinetic model, and finally the potential impact factors of multiple-peak pattern are assessed through the global and time-varying sensitivity analyses. RESULTS: All annual model-based and model-free basic reproduction numbers were significantly higher than one. The school opening both in the spring and fall semester, meteorological e ect in the spring semester, and the interactions among them were strongly correlated with the annual model-based basic reproduction number, which were the main underlying factors on the annual multiple-peak pattern of HFMD outbreaks. CONCLUSIONS: School opening was primarily responsible for peaks of HFMD outbreaks and meteorological factors in the spring semester should also be highly concerned. The optimum timing for social distance implementation is at the beginning of every school semester and health education focusing on personal hygiene and good sanitation should be highlighted in the spring semester.

[Advances in the research of application of clinical decision support system in fluid resuscitation following severe burn].

Although guidelines and formulas have been developed through clinical practice to define infusion rate and volume, over- and under-resuscitation are still common, followed by increasing morbidity and mortality. In order to establish an effective management for early fluid resuscitation, the clinical decision support system (CDSS) has been established. The CDSS, by utilizing information systems coupled with decision support technology, could provide recommendations for the amount of fluid to be infused based on measured biological response. The results showed that patients treated with CDSS had a significantly lower mortality, increased ventilator-free days, and ICU-free days as compared with those treated with traditional fluid management. This article reviews the concepts as well as the result of recent clinical studies of CDSS for burn patients.