Biomedical subjects

Wendi Wang

Publications and source records attributed to Wendi Wang.

6 recordsLinked to original sources

PubMed2006

Backward bifurcation of an epidemic model with treatment.

An epidemic model with a limited resource for treatment is proposed to understand the effect of the capacity for treatment. It is assumed that treatment rate is proportional to the number of infectives below the capacity and is a constant when the number of infectives is greater than the capacity. It is found that a backward bifurcation occurs if the capacity is small. It is also found that there exist bistable endemic equilibria if the capacity is low.

Communicable Diseases↗

PubMed2006

Prey-predator system with parental care for predators.

A stage structure is incorporated into a prey-predator model in which predators are split into immature predators and mature predators. It is assumed that immature predators are raised by their parents in the sense that they cannot catch the prey and their foods are provided by parents. Further, it is assumed that the maturation rate of immature predators is a function of the food availability for one immature individual. It is found that the model admits periodic solutions which are produced from the stage structure. Further, it is shown that two stability switches of positive equilibria may occur due to the transition rate incorporating the influence of nutrient, and that the enrichment of adult predators may lead to the catastrophe of the ecological system.

Animals↗

PubMed2005

Species coexistence and periodicity in host-host-pathogen models.

Models for the transmission of an infectious disease in one and two host populations with and without self-regulation are analyzed. Many unusual behaviors such as multiple positive equilibria and periodic solutions occur in previous models that use the mass-action (density-dependent) incidence. In contrast, the models formulated using the frequency-dependent (standard) incidence have the behavior of a classic endemic model, since below the threshold, the disease dies out, and above the threshold, the disease persists and the infectious fractions approach an endemic equilibrium. The results given here reinforce previous examples in which there are major differences in behavior between models using mass-action and frequency-dependent incidences.

Animals↗

PubMed2004

Simulating the SARS outbreak in Beijing with limited data.

We propose a mathematical model to simulate the SARS outbreak in Beijing. The model consists of six subpopulations, namely susceptible, exposed, quarantined, suspect, probable and removed, as China started to report SARS cases as suspect and probable separately from April 27 and cases transferred from suspect class to probable class from May 2. By simplifying the model to a two-compartment suspect-probable model and a single-compartment probable model and using limited data, we are able to simulate the SARS outbreak in Beijing. We estimate that the reproduction number varies from 1.0698 to 3.2524 and obtain certain important epidemiological parameters.

China↗

PubMed2004

An epidemic model in a patchy environment.

An epidemic model is proposed to describe the dynamics of disease spread among patches due to population dispersal. We establish a threshold above which the disease is uniformly persistent and below which disease-free equilibrium is locally attractive, and globally attractive when both susceptible and infective individuals in each patch have the same dispersal rate. Two examples are given to illustrate that the population dispersal plays an important role for the disease spread. The first one shows that the population dispersal can intensify the disease spread if the reproduction number for one patch is large, and can reduce the disease spread if the reproduction numbers for all patches are suitable and the population dispersal rate is strong. The second example indicates that a population dispersal results in the spread of the disease in all patches, even though the disease can not spread in each isolated patch.

Communicable Diseases↗

PubMed2004

A predator-prey model with infected prey.

A predator-prey model with logistic growth in the prey is modified to include an SIS parasitic infection in the prey with infected prey being more vulnerable to predation. Thresholds are identified which determine when the predator population survives and when the disease remains endemic. For some parameter values the greater vulnerability of the infected prey allows the predator population to persist, when it would otherwise become extinct. Also the predation on the more vulnerable prey can cause the disease to die out, when it would remain endemic without the predators.

Animals↗