Seasonal infection dynamics characterise many host-parasite interactions, as abiotic conditions drive fundamental biological processes in both hosts and parasites. The extent to which seasonal cycles in parasite abundance are universal, and whether the same underlying mechanisms are responsible for seasonality across different host-parasite associations, have received little attention to date. Here, global patterns of seasonal infection dynamics are tested using a meta-analysis of 693 seasonal contrasts in the local abundance of metazoan parasites in aquatic vertebrates, representing 343 parasite species and 148 host species. These include both contrasts between winter and summer in temperate systems, and between wet and dry seasons in tropical systems. Overall, the analysis found no evidence that seasonal infection dynamics are universal, nor that they are controlled by the same factors. More specifically, the results indicate no overall effect of the magnitude of local seasonal differences in abiotic conditions (temperature or precipitation), type of host (amphibian or fish), habitat (freshwater, coastal marine or deep-sea), host body length, or mode of transmission (skin contact or trophic) on the extent of seasonal differences in parasite infections. Instead, the results revealed many clear taxon-specific or habitat-specific patterns of seasonal infection dynamics, with some parasite or host taxa generally showing distinct peaks in infections in summer or dry seasons, and others showing no seasonal changes. The present findings serve to identify empirically which host-parasite associations are most likely to respond to changing climatic conditions, and thus provide useful information for fisheries and aquaculture.

季节性感染动态表征了许多宿主 - 寄生虫相互作用，因为非生物条件驱动宿主和寄生虫的基本生物过程。寄生虫丰度的季节性周期具有普遍性的程度，以及相同的潜在机制是否对不同宿主 - 寄生虫关联的季节性负责，迄今为止很少受到关注。在这里，使用对水生脊椎动物后生动物寄生虫局部丰度的 693 个季节性对比的荟萃分析来测试全球季节性感染动态模式，代表 343 个寄生虫物种和 148 个宿主物种。其中包括温带系统中冬季和夏季之间的对比，以及热带系统中干湿季节之间的对比。总体而言，分析发现没有证据表明季节性感染动态是普遍的，也不是它们受相同的因素控制。更具体地说，结果表明非生物条件（温度或降水）、宿主类型（两栖动物或鱼类）、栖息地（淡水、沿海海洋或深海）、宿主体长、或传播方式（皮肤接触或营养）对寄生虫感染季节性差异的程度。相反，结果揭示了季节性感染动态的许多明确的分类群特定或栖息地特定模式，一些寄生虫或宿主分类群通常在夏季或旱季表现出明显的感染高峰，而另一些则没有季节性变化。目前的研究结果有助于根据经验确定哪些宿主 - 寄生虫关联最有可能对不断变化的气候条件做出反应，