Within-host mathematical modelling of the incubation period of Salmonella Typhi

Mechanistic mathematical models are often employed to understand the dynamics of infectious diseases within a population or within a host. They provide estimates that may not otherwise be available. We have developed a within-host mathematical model in order to understand how the pathophysiology of Salmonella Typhi contributes to its incubation period. The model describes the process of infection from ingestion to onset of clinical illness using a set of ordinary differential equations. The model was parameterised using estimated values from human and mouse experimental studies and the incubation period was estimated as 9.6 days. A sensitivity analysis was also conducted to identify the parameters that most affect the derived incubation period. The migration of bacteria to the caecal lymph node was observed as a major bottle neck for infection. The sensitivity analysis indicated the growth rate of bacteria in late phase systemic infection and the net population of bacteria in the colon ...机理数学模型（Mechanistic mathematical models）常被用于解析种群或宿主内的传染病动力学，可提供常规途径无法获得的定量估算结果。为阐明伤寒沙门氏菌（Salmonella Typhi）的病理生理过程如何影响其潜伏期，本研究构建了一套宿主内数学模型。该模型通过一组常微分方程（ordinary differential equations）描述了从病原菌摄入到临床病症发作的完整感染过程。研究结合人类与小鼠实验研究的估算值对模型进行参数化，并推算出潜伏期为9.6天。同时还开展了敏感性分析（sensitivity analysis），以识别对推导所得潜伏期影响最为显著的模型参数。研究观察到，细菌向盲肠淋巴结（caecal lymph node）的迁移是感染过程的关键瓶颈环节。敏感性分析结果显示，细菌在晚期全身感染阶段的生长速率以及结肠内细菌的净种群数量……