Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ciudad Real, Spain.
VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid, Spain.
Sci Total Environ. 2022 Dec 20;853:158633. doi: 10.1016/j.scitotenv.2022.158633. Epub 2022 Sep 7.
Tick abundance is an essential demographic parameter to infer tick-borne pathogen transmission risks. Spatiotemporal patterns of tick abundance are heterogeneous, so its determinants at small spatial scales need to be understood to reduce their negative effects on hosts. Current knowledge of these determinants is scarce, especially in Mediterranean environments, limiting the possibilities for designing efficient tick control strategies. With the goal of unravelling tick abundance determinants and informing new tick management strategies, we estimated tick burdens on 1965 wild ungulates in Doñana National Park, Spain, annually between 2010 and 2020. Under the hypothesis of a predominant host influence on tick abundance, we modelled the burdens of Rhipicephalus annulatus, Hyalomma lusitanicum, and Ixodes ricinus with relevant predictors grouped into four factors: i) environment; ii) host population; iii) host individual; and iv) land-use. Generalized linear mixed models with a zero-inflated negative binomial distribution were built. Additionally, we analysed the differential contribution to abundance of each factor by deviance partitioning. We finally estimated the similarity in the environmental space of tick species by analysing their niche overlap with the environmental principal component analysis method. Our work hypothesis was confirmed for R. annulatus and H. lusitanicum, but we found that tick abundance at a fine spatial scale is jointly driven by multiple drivers, including all four factors considered in this study. This result points out that understanding the demography of ticks is a complex multifactorial issue, even at small spatial scales. We found no niche differences between the three tick species at the study spatial scale, thus showing similar host and environmental dependencies. Overall results identify that host aggregation areas displaying environmentally favourable traits for ticks are relevant tick and vector-borne pathogen transmission hotspots. Our findings will facilitate the design of new strategies to reduce the negative effects of tick parasitism.
蜱虫密度是推断蜱传病原体传播风险的重要人口统计学参数。蜱虫密度的时空模式具有异质性，因此需要了解小空间尺度上的决定因素，以降低其对宿主的负面影响。目前对这些决定因素的了解很少，特别是在地中海环境中，限制了设计有效蜱虫控制策略的可能性。为了揭示蜱虫密度的决定因素，并为新的蜱虫管理策略提供信息，我们在 2010 年至 2020 年期间，每年在西班牙多纳纳国家公园对 1965 只野生有蹄类动物进行了蜱虫负担估计。在主要宿主对蜱虫密度有影响的假设下，我们用相关预测因子将蜱虫的负担分组为四个因素：i）环境；ii）宿主种群；iii）宿主个体；iv）土地利用，对 Rhipicephalus annulatus、Hyalomma lusitanicum 和 Ixodes ricinus 进行了建模。建立了具有零膨胀负二项分布的广义线性混合模型。此外，我们通过偏差划分分析了每个因素对丰度的贡献差异。最后，我们通过环境主成分分析方法分析了各物种的生态位重叠，来估计蜱虫物种在环境空间中的相似性。我们的工作假设得到了 R. annulatus 和 H. lusitanicum 的证实，但我们发现，在精细的空间尺度上，蜱虫的丰度是由多个驱动因素共同驱动的，包括本研究中考虑的所有四个因素。这一结果表明，即使在小空间尺度上，理解蜱虫的种群动态也是一个复杂的多因素问题。在研究的空间尺度上，我们没有发现这三种蜱虫在生态位上的差异，因此它们对宿主和环境的依赖程度相似。总体结果表明，显示出对蜱虫有利的环境特征的宿主聚集区是相关的蜱虫和虫媒病原体传播热点。我们的研究结果将有助于设计新的策略来减少蜱虫寄生的负面影响。
