College of Arts and Sciences, Shanghai Maritime University, Shanghai, PR China.
Department of Mathematics, Shanghai Normal University, Shanghai, PR China.
Math Biosci. 2020 Jun;324:108326. doi: 10.1016/j.mbs.2020.108326. Epub 2020 Feb 22.
Trypanosoma rangeli (T. rangeli), a parasite, is not pathogenic to human but pathogenic to some vector species to induce the behavior changes of infected vectors and subsequently impact the transmission dynamics of other diseases such as Chagas disease which shares the same vector species. Here we develop a mathematical model and conduct qualitative analysis for the transmission dynamics of T. rangeli. We incorporate both systemic and co-feeding transmission routes, and account for the pathogenic effect using infection-induced fecundity and fertility change of the triatomine bugs. We derive two thresholds R (the triatomine bug basic reproduction number) and R (the T. rangeli basic reproduction number) to delineate the dynamical behaviors of the ecological and epidemiological systems. We show that when R>1 and R>1, a unique parasite positive equilibrium E* appears. We find that E* can be unstable and periodic oscillations can be observed where the pathogenic effect plays a significant role. Implications of the qualitative analysis and numerical simulations suggest the need of an integrative vector-borne disease prevention and control strategy when multiple vector-borne diseases are transmitted by the same set of vector species.
冈比亚锥虫（T. rangeli）是一种寄生虫，对人类没有致病性，但对某些媒介物种具有致病性，能诱导受感染媒介的行为改变，从而影响其他疾病（如恰加斯病）的传播动态，因为这些疾病的媒介物种相同。在这里，我们开发了一个数学模型，并对 T. rangeli 的传播动力学进行了定性分析。我们结合了全身和共食传播途径，并利用感染诱导的三锥虫的繁殖力和生殖力变化来考虑致病作用。我们推导出两个阈值 R（三锥虫基本繁殖数）和 R（T. rangeli 基本繁殖数）来描绘生态和流行病学系统的动态行为。我们表明，当 R>1 且 R>1 时，出现唯一的寄生虫阳性平衡点 E*。我们发现，当致病作用起重要作用时，E*可能不稳定，会出现周期性振荡。定性分析和数值模拟的结果表明，当同一组媒介物种传播多种媒介传播疾病时，需要采取综合的媒介传播疾病预防和控制策略。
