Division of Animal Production and Public Health, The Veterinary School, University of Glasgow, Glasgow, UK.
Parasite Immunol. 2013 Dec;35(12):421-32. doi: 10.1111/pim.12045.
Given their global distribution and abilities to persist in the host, helminths can play a crucial role in affecting risk of infections by increasing individual variation in infection. Helminth co-infections are of particular interest because by altering host immune responses, they can modify host susceptibility and thus intensity and transmission of other parasites/pathogens. The dynamics of co-infection were examined using two helminths of the European rabbit. Individuals were simultaneously challenged with a primary dose of both parasites, and changes in intensity were examined in relation to local and systemic immune responses. Both helminths persisted in co-infected rabbits; however, contrasting dynamics and immune responses were observed. Graphidium strigosum intensity was high throughout the co-infection, while Trichostrongylus retortaeformis intensity decreased but was not completely cleared. A Th2 response was observed against G. strigosum, while a mixed Th1/Th2 profile was found to T. retortaeformis. A comparison with our previous work on single infections showed that G. strigosum intensity was higher in co-infected than single infected hosts, while T. retortaeformis showed no significant changes. Differences were also observed in the cytokine profiles, blood cell concentrations and antibody trends. Overall, host variability during helminth co-infections can be generated by significant differences in immune responses and/or parasite dynamics.
鉴于它们的全球分布和在宿主中持续存在的能力，寄生虫可以通过增加个体感染的变异性来在影响感染风险方面发挥关键作用。寄生虫的合并感染特别有趣，因为它们可以改变宿主的免疫反应，从而改变宿主的易感性，进而改变其他寄生虫/病原体的强度和传播。通过同时用两种寄生虫对欧洲兔进行初级剂量挑战，研究了合并感染的动态，并检查了局部和全身免疫反应与感染强度变化的关系。两种寄生虫都在合并感染的兔子中持续存在；然而，观察到了不同的动态和免疫反应。Graphidium strigosum 的强度在整个合并感染过程中一直很高，而 Trichostrongylus retortaeformis 的强度下降但并未完全清除。针对 G. strigosum 观察到 Th2 反应，而针对 T. retortaeformis 发现了混合 Th1/Th2 特征。与我们之前关于单一感染的工作进行比较表明，在合并感染的宿主中，G. strigosum 的强度高于单一感染的宿主，而 T. retortaeformis 没有明显变化。细胞因子谱、血细胞浓度和抗体趋势也存在差异。总体而言，寄生虫合并感染期间宿主的可变性可以由免疫反应和/或寄生虫动态的显著差异产生。
