Recent models suggest a relationship exists between community diversity and pathogen prevalence, the proportion of individuals in a population that are infected by a pathogen, with most inferences tied to assemblage structure. Two contrasting outcomes of this relationship have been proposed: the "dilution effect" and the "amplification effect." Small mammal assemblage structure in disturbed habitats often differs from assemblages in sylvan environments, and hantavirus prevalence is often negatively correlated with habitats containing high species diversity via dilution effect dynamics. As species richness increases, prevalence of infection often is decreased. However, anthropogenic changes to sylvan landscapes have been shown to decrease species richness and/or increase phylogenetic similarities within assemblages. Between January 2011 and January 2016, we captured and tested 2406 individual small mammals for hantavirus antibodies at 20 sites across Texas and México and compared differences in hantavirus seroprevalence, species composition, and assemblage structure between sylvan and disturbed habitats. We found 313 small mammals positive for antibodies against hantaviruses, evincing an overall prevalence of 9.7% across all sites. In total, 40 species of small mammals were identified comprising 2 taxonomic orders (Rodentia and Eulipotyphla). By sampling both habitat types concurrently, we were able to make real-world inferences into the efficacy of dilution effect theory in terms of hantavirus ecology. Our hypothesis predicting greater species richness higher in sylvan habitats compared to disturbed areas was not supported, suggesting the characteristics of assemblage structure do not adhere to current conceptions of species richness negatively influencing prevalence via a dilution effect.

中文翻译：

---

物种同一性取代了德克萨斯州和墨西哥各地汉坦病毒流行率的稀释效应。

最近的模型表明，群落多样性与病原体流行率（群体中被病原体感染的个体比例）之间存在关系，大多数推论与组合结构有关。人们提出了这种关系的两种截然不同的结果：“稀释效应”和“放大效应”。受干扰栖息地中的小型哺乳动物群落结构通常与森林环境中的群落结构不同，并且汉坦病毒的流行通常通过稀释效应动态与包含高物种多样性的栖息地呈负相关。随着物种丰富度的增加，感染流行率往往会降低。然而，对森林景观的人为改变已被证明会降低物种丰富度和/或增加组合内的系统发育相似性。2011 年 1 月至 2016 年 1 月期间，我们在德克萨斯州和墨西哥的 20 个地点捕获并测试了 2406 只小型哺乳动物的汉坦病毒抗体，并比较了森林和受干扰栖息地之间汉坦病毒血清流行率、物种组成和组合结构的差异。我们发现 313 只小型哺乳动物的汉坦病毒抗体呈阳性，表明所有地点的总体患病率为 9.7%。总共鉴定出 40 种小型哺乳动物，包括 2 个分类目（啮齿目和真鼠目）。通过同时对两种栖息地类型进行采样，我们能够对汉坦病毒生态学方面的稀释效应理论的有效性进行现实世界的推论。我们的假设预测，与受干扰的地区相比，森林栖息地的物种丰富度更高，但这一假设并未得到支持，这表明组合结构的特征并不符合当前物种丰富度通过稀释效应对流行率产生负面影响的概念。