Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
Proc Biol Sci. 2024 Oct;291(2033):20241673. doi: 10.1098/rspb.2024.1673. Epub 2024 Oct 16.
Two key epidemiological parameters, prevalence and mean intensity of infection, together capture the abundance of macroparasite populations, the strength of density-dependent effects they experience, their potential impact on host population dynamics and the selective pressures they exert on their hosts. Yet, the drivers of the extensive variation observed in prevalence and mean intensity of infection, even among related parasite taxa infecting related hosts, remain mostly unknown. We performed phylogenetically grounded Bayesian modelling across hundreds of amphibian populations to test the effects of various predictors of prevalence and intensity of infection by six families of helminth parasites. We focused on the potential effects of key host traits and environmental factors pertinent to focal host populations, i.e. the local diversity of the amphibian community and local climatic variables. Our analyses revealed several important determinants of prevalence or intensity of infection in various parasite families, but none applying to all families. Our study uncovered no universal driver of parasite infection levels, even among parasite taxa from the same phylum, or with similar life cycles and transmission modes. Although local variables not considered here may have effects extending across taxa, our findings suggest the need for a taxon-specific approach in any attempt to predict disease dynamics and impacts in the face of environmental and climatic changes.
两个关键的流行病学参数，即流行率和平均感染强度，共同捕获了大型寄生虫种群的丰度、它们所经历的密度依赖效应的强度、它们对宿主种群动态的潜在影响以及它们对宿主施加的选择压力。然而，即使在感染相关宿主的相关寄生虫分类群中，流行率和平均感染强度所观察到的广泛变异的驱动因素在很大程度上仍然未知。我们对数百个两栖动物种群进行了基于系统发育的贝叶斯建模，以测试六种寄生虫科的流行率和感染强度的各种预测因子的影响。我们专注于与焦点宿主种群相关的关键宿主特征和环境因素的潜在影响，即当地的两栖动物群落多样性和当地的气候变量。我们的分析揭示了各种寄生虫科流行率或感染强度的几个重要决定因素，但没有一个适用于所有科。我们的研究发现，即使在同一门的寄生虫分类群中，或者具有相似生命周期和传播模式的寄生虫分类群中，也没有普遍的寄生虫感染水平驱动因素。尽管这里未考虑的局部变量可能具有跨越分类群的影响，但我们的研究结果表明，在面对环境和气候变化时，任何试图预测疾病动态和影响的尝试都需要采取特定于分类群的方法。
