Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7ZB, UK.
Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK.
Proc Biol Sci. 2024 Apr 30;291(2021):20240103. doi: 10.1098/rspb.2024.0103. Epub 2024 Apr 17.
Within-host interactions among coinfecting parasites can have major consequences for individual infection risk and disease severity. However, the impact of these within-host interactions on between-host parasite transmission, and the spatial scales over which they occur, remain unknown. We developed and apply a novel spatially explicit analysis to parasite infection data from a wild wood mouse () population. We previously demonstrated a strong within-host negative interaction between two wood mouse gastrointestinal parasites, the nematode and the coccidian , using drug-treatment experiments. Here, we show this negative within-host interaction can significantly alter the between-host transmission dynamics of , but only within spatially restricted neighbourhoods around each host. However, for the closely related species , which experiments show does not interact strongly with , we did not find any effect on transmission over any spatial scale. Our results demonstrate that the effects of within-host coinfection interactions can ripple out beyond each host to alter the transmission dynamics of the parasites, but only over local scales that likely reflect the spatial dimension of transmission. Hence there may be knock-on consequences of drug treatments impacting the transmission of non-target parasites, altering infection risks even for non-treated individuals in the wider neighbourhood.
宿主内共生寄生虫之间的相互作用可能对个体感染风险和疾病严重程度产生重大影响。然而，这些宿主内相互作用对宿主间寄生虫传播的影响，以及它们发生的空间尺度，仍然未知。我们开发并应用了一种新的空间显式分析方法，来分析来自野生林鼠（）种群的寄生虫感染数据。我们之前使用药物处理实验证明了两种林鼠胃肠道寄生虫之间存在强烈的宿主内负相互作用，即线虫和球虫。在这里，我们表明这种宿主内的负相互作用可以显著改变的宿主间传播动态，但仅在每个宿主周围的空间受限的邻域内。然而，对于密切相关的物种，实验表明它与之间没有强烈的相互作用，我们没有发现任何空间尺度上的传播效应。我们的研究结果表明，宿主内共感染相互作用的影响可以超出每个宿主，改变寄生虫的传播动态，但仅在可能反映传播空间维度的局部尺度上。因此，药物治疗影响非目标寄生虫传播的连锁反应可能会改变感染风险，即使是在更广泛的邻域中未接受治疗的个体也是如此。
