Dobson Andrew D M, Auld Stuart K J R
Am Nat. 2016 Apr;187(4):405-22. doi: 10.1086/685445. Epub 2016 Feb 29.
Models used to investigate the relationship between biodiversity change and vector-borne disease risk often do not explicitly include the vector; they instead rely on a frequency-dependent transmission function to represent vector dynamics. However, differences between classes of vector (e.g., ticks and insects) can cause discrepancies in epidemiological responses to environmental change. Using a pair of disease models (mosquito- and tick-borne), we simulated substitutive and additive biodiversity change (where noncompetent hosts replaced or were added to competent hosts, respectively), while considering different relationships between vector and host densities. We found important differences between classes of vector, including an increased likelihood of amplified disease risk under additive biodiversity change in mosquito models, driven by higher vector biting rates. We also draw attention to more general phenomena, such as a negative relationship between initial infection prevalence in vectors and likelihood of dilution, and the potential for a rise in density of infected vectors to occur simultaneously with a decline in proportion of infected hosts. This has important implications; the density of infected vectors is the most valid metric for primarily zoonotic infections, while the proportion of infected hosts is more relevant for infections where humans are a primary host.
用于研究生物多样性变化与媒介传播疾病风险之间关系的模型通常并未明确纳入媒介；相反，它们依赖频率依赖型传播函数来体现媒介动态。然而，不同类别的媒介（如蜱虫和昆虫）之间的差异可能导致对环境变化的流行病学反应出现差异。我们使用一对疾病模型（蚊媒和蜱媒疾病模型），在考虑媒介与宿主密度之间不同关系的同时，模拟了替代性和叠加性生物多样性变化（分别指无能力宿主替代有能力宿主或添加到有能力宿主中）。我们发现不同类别的媒介之间存在重要差异，包括在蚊媒模型中叠加性生物多样性变化下疾病风险放大的可能性增加，这是由更高的媒介叮咬率驱动的。我们还提请注意更普遍的现象，例如媒介初始感染患病率与稀释可能性之间的负相关关系，以及感染媒介密度上升与感染宿主比例下降同时发生的可能性。这具有重要意义；感染媒介的密度是主要人畜共患感染的最有效指标，而感染宿主的比例对于以人类为主要宿主的感染更为相关。
