Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland.
Parasitology. 2024 Jan;151(1):58-67. doi: 10.1017/S0031182023001130. Epub 2023 Nov 20.
Recent outbreaks of various infectious diseases have highlighted the ever-present need to understand the drivers of the outbreak and spread of disease. Although much of the research investigating diseases focuses on single infections, natural systems are dominated by multiple infections. These infections may occur simultaneously, but are often acquired sequentially, which may alter the outcome of infection. Using waterfleas () as a model organism, we examined the outcome of sequential and simultaneous multiple infections with 2 microsporidian parasites ( and ) in a fully factorial design with 9 treatments and 30 replicates. We found no differences between simultaneous and sequential infections. However, fitness was impeded by multiple infection due to increased host mortality, which gave less time to grow. Host fecundity was also reduced across all treatments, but animals infected with at a younger age produced the fewest offspring. As is both horizontally and vertically transmitted, this reduction in offspring may have further reduced fitness in co-infected treatments. Our findings suggest that in natural populations where both species co-occur, may evolve to higher levels of virulence following frequent co-infection by .
最近各种传染病的爆发突显了人们一直以来对了解疾病爆发和传播驱动因素的需求。尽管许多研究疾病的工作都集中在单一感染上，但自然系统主要由多种感染所主导。这些感染可能同时发生，但通常是顺序发生的，这可能会改变感染的结果。我们使用水蚤（）作为模式生物，在一个具有 9 种处理和 30 个重复的完全析因设计中，研究了 2 种微孢子虫寄生虫（和）的顺序和同时多重感染的结果。我们没有发现同时感染和顺序感染之间有差异。然而，由于宿主死亡率增加导致感染时间减少，多感染会阻碍的适应性，从而减少的生长时间。所有处理都会降低宿主的繁殖力，但在更年轻时感染的动物所产生的后代数量最少。由于是水平和垂直传播的，因此这种后代数量的减少可能会进一步降低共同感染处理中感染的适应性。我们的研究结果表明，在两种物种共存的自然种群中，可能会在经常受到共同感染后进化出更高水平的毒力。
