Sit-and-wait pathogens: Consequences of heterogeneity in pathogen exposure dynamics for environmentally persistent pathogens

传播是宿主-病原体系统的基本组成部分。尽管生物学上很复杂 相互作用以确定病原体是否成功感染宿主、传播 参数通常假定每个接触点的传输概率恒定。可能影响风险的因素 感染包括接触频率、接触持续时间和在接触期间获得的剂量 相互作用，统称为传播决定因素。这些感染的决定因素 可因主机和传输路径的不同而不同(例如直接和间接)，并具有深远的 对疾病动力学的影响。最终，对传输中的异质性如何进行机械性的理解 暴露事件之间的概率对疾病动态的贡献仍然是一个重要的突出问题 传染病的生态学和进化中的问题。在这里，我们试图阐明因素是如何 确定传播成功与否会影响感染、流行的概率 动力学和病原体进化。 具体地说，我们将调查传播决定因素(病原体剂量、接触时间和 接触频率)因接触途径(直接和间接)而异，并最终导致 一种新出现的蛇多宿主疾病的动力学。蛇真菌病(SFD)是由， 它是一种环境持久性真菌病原体，到目前为止，它一直是 在三大洲的42种野生蛇中有记录，并导致了严重的 几个物种的数量在减少。稻瘟病菌通过直接和间接接触传播， 受SFD影响的蛇物种的行为自然会随着接触时间和接触强度的不同而变化 梯度，这使得这是一个理想的系统来了解暴露事件的变化对 疾病动力学。这项工作将突出导致蛇类变异的重要机制。 下跌，更广泛地说，提供了对理论基础和深刻影响的洞察， 决定成功传播的因素可能对传染病暴发产生影响。 该提案将利用我们在此多主机系统中的最新进展，并结合使用 现场、实验和建模方法，以提供对曝光动态的关键洞察 这些事件会对传染病产生连锁效应。

Transmission is a fundamental component of host-pathogen systems. Despite complex biological processes interacting to determine whether a pathogen successfully infects a host, transmission parameters often assume a constant per-contact transmission probability. Factors that can influence risk of infection include the frequency of exposures, duration of a contact, and dose acquired during an interaction, which are collectively referred to as transmission determinants. These determinants of infection can vary among hosts and between routes of transmission (e.g. direct and indirect) and have profound effects on disease dynamics. Ultimately, a mechanistic understanding of how heterogeneity in transmission probabilities among exposure events contributes to disease dynamics remains an important outstanding question in the ecology and evolution of infectious diseases. Here we seek to elucidate how factors determining transmission success influence the probability of acquiring infection, epidemic dynamics, and pathogen evolution. Specifically, we will investigate how transmission determinants (pathogen dose, contact duration, and contact frequency) vary among exposure routes (direct and indirect) and ultimately contribute to the dynamics of an emerging multi-host disease of snakes. Snake fungal disease (SFD) is caused by, Ophidiomyces ophidiicola, which is an environmentally persistent fungal pathogen that, to date, has been documented in more than 42 species of wild snakes on three continents, and has contributed to the severe declines of several species. O. ophidiicola is transmitted through direct and indirect contacts, and the behavior of snake species affected by SFD naturally vary along an exposure duration and contact intensity gradient, making this an ideal system for understanding the effects of variation in exposure events on disease dynamics. This work will highlight important mechanisms that contribute to variation in snake declines, and more broadly, provide insight into the theoretical underpinnings and profound effects that factors determining successful transmission can have on infectious disease outbreaks. This proposal will leverage our recent advances in this multi-host system and use a combination of field, experimental, and modeling approaches to provide critical insight into how the dynamics of exposure events have cascading effects on infectious disease.