BackgroundLymphatic filariasis is a globally neglected tropical parasitic disease which affects individuals of all ages and leads to an altered lymphatic system and abnormal enlargement of body parts.MethodsA mathematical model of lymphatic filariaris with intervention strategies is developed and analyzed. Control of infections is analyzed within the model through medical treatment of infected-acute individuals and quarantine of infected-chronic individuals.ResultsWe derive the effective reproduction number, and its interpretation/investigation suggests that treatment contributes to a reduction in lymphatic filariasis cases faster than quarantine. However, this reduction is greater when the two intervention approaches are applied concurrently.ConclusionsNumerical simulations are carried out to monitor the dynamics of the filariasis model sub-populations for various parameter values of the associated reproduction threshold. Lastly, sensitivity analysis on key parameters that drive the disease dynamics is performed in order to identify their relative importance on the disease transmission.

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 malaria–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.

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This paper explores the dynamics of respiratory gases interactions which are accompanied by the loss of water through an insect’s spiracle. Here we investigate and analyze this interaction by deriving a system of ordinary differential equations for oxygen, carbon dioxide, and water vapor. The analysis is carried out in continuous time. The purpose of the research is to determine bounds for the gas volumes and to discuss the complexity and stability of the equilibria. Numerical simulations also demonstrate the dynamics of our model utilizing the new conditions for stability and instability.

In this study, a high-order compact finite difference method is used to solve boundary value problems with Robin boundary conditions. The norm is to use a first-order finite difference scheme to approximate Neumann and Robin boundary conditions, but that compromises the accuracy of the entire scheme. As a result, new higher-order finite difference schemes for approximating Robin boundary conditions are developed in this work. Six examples for testing the applicability and performance of the method are considered. Convergence analysis is provided, and it is consistent with the numerical results. The results are compared with the exact solutions and published results from other methods. The method produces highly accurate results, which are displayed in tables and graphs.

In this paper two models for movement of respiratory gases in the insect trachea are presented. One model considers the tracheal system as a single flexible compartment while the other model considers the trachea as a single flexible compartment with gas exchange. This work represents an extension of Ben-Tal's work on compartmental gas exchange in human lungs and is applied to the insect tracheal system. The purpose of the work is to study nonlinear phenomena seen in the insect respiratory system. It is assumed that the flow inside the trachea is laminar, and that the air inside the chamber behaves as an ideal gas. Further, with the isothermal assumption, the expressions for the tracheal partial pressures of oxygen and carbon dioxide, rate of volume change, and the rates of change of oxygen concentration and carbon dioxide concentration are derived. The effects of some flow parameters such as diffusion capacities, reaction rates and air concentrations on net flow are studied. Numerical simulations of the tracheal flow characteristics are performed. The models developed provide a mathematical framework to further investigate gas exchange in insects.

Background Interleukin-4-induced gene 1 (IL-4i1) encodes L-phenylalanine oxidase that catabolizes phenylalanine into phenylpyruvate. IL-4i1 is mainly expressed by antigen-presenting cells, inhibits T-cell proliferation, regulates B-cell activation, drives macrophage polarization and modulates Th1 inflammatory immune responses, but its role in bacterial infections is understudied. Methods Herein, we evaluated IL-4i1 deletion in macrophages and mice upon infection with virulent H37Rv and W-Beijing lineage hypervirulent HN878 Mycobacterium tuberculosis (Mtb) strains. The bacterial growth and pro-inflammatory responses were measured in vitro and in vivo. Histopathological analysis, lung immune cell recruitment and macrophage activation were assessed at the early and chronic stages of Mtb infection. Results IL-4i1 -/- mice displayed increased protection against acute H37Rv and HN878 and chronic HN878 Mtb infections; with reduced lung bacterial burdens and altered antigen-presenting cell (APC) responses when compared to wild-type mice. Moreover, “M1-like” interstitial macrophage numbers, nitrite and interferon production were significantly increased in IL-4i1 -/- mice when compared to wild-type mice during acute Mtb HN878 infection. Conclusions Together, these data suggest that IL-4i1 regulates APC-mediated inflammatory responses during acute and chronic Mtb infection. Hence IL-4i1 targeting has the potential as an immunomodulatory target for host-directed therapy.