Multiple transmission routes sustain high prevalence of a virulent parasite in a butterfly host

Understanding factors that allow highly virulent parasites to reach high infection prevalence in host populations is important for managing infection risks to human and wildlife health. Multiple transmission routes have been proposed as one mechanism by which virulent pathogens can achieve high prevalence, underscoring the need to investigate this hypothesis through an integrated modeling-empirical framework. Here, we examine a harmful specialist protozoan infecting monarch butterflies that commonly reaches high prevalence (50-100%) in resident populations. We integrate field and modeling work to show that a combination of three empirically-supported transmission routes (vertical, adult transfer, and environmental transmission) can produce and sustain high infection prevalence in this system. Although horizontal transmission is necessary for parasite invasion, most new infections post-establishment arise from vertical transmission. Our study predicts that multiple transmission routes, c...

解析可使高致病性寄生虫在宿主种群中达到高感染流行率（prevalence）的关键影响因素，对于管控人类与野生动物健康的感染风险具有重要意义。多传播途径被认为是致病性病原体达成高感染流行率的潜在机制之一，这突显了需通过建模与实证整合研究框架（integrated modeling-empirical framework）对该假说开展验证的必要性。本研究针对一种侵染帝王蝶的有害专性寄生原生动物展开分析，该寄生虫在帝王蝶常驻种群中通常可达到50%至100%的高感染流行率。我们结合野外调查与模型模拟工作，证实了三种经实证支持的传播途径——垂直传播（vertical transmission）、成虫接触传播（adult transfer）以及环境传播（environmental transmission）——的协同作用，可在该研究体系中产生并维持高感染流行率。尽管水平传播（horizontal transmission）是寄生虫成功入侵宿主种群的必要条件，但在种群定植后，绝大多数新发感染均源于垂直传播。本研究预测，多种传播途径，c...