Rodríguez-Pastor Ruth, Garrido Mario, Knossow Nadav, Shahar Naama, Flatau Ron, Hawlena Hadas
Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
Agri-Food Institute of Aragon (IA2)-University of Zaragoza-CITA, Zaragoza, Spain.
Sci Rep. 2025 Jun 2;15(1):19256. doi: 10.1038/s41598-025-01351-1.
Variation in infection dynamics across host species can profoundly influence parasite epidemiology, ecology, and evolution. However, because experiments involving multiple hosts and multiple parasite species that capture the full infection dynamics within hosts are rare, the underlying mechanisms of host heterogeneity effects across different parasite species remain largely unknown. We dissected the specific roles of host and pathogen effects in shaping within-host infection dynamics using a model system comprising three coexisting rodent species from Israel's northwestern Negev Desert and their predominant bacterial pathogens, Bartonella krasnovii A2 and Mycoplasma haemomuris-like bacterium. To test whether the effects of host species heterogeneity on parasite dynamics mainly derive from host trait variation ("host trait variation hypothesis") or rather reflect a unique host-parasite interaction ("specific host-parasite interaction" hypotheses), we inoculated rodents of the three species (Gerbillus andersoni, G. pyramidum, and G. gerbillus) with either Bartonella or Mycoplasma and compared their infection dynamics during primary infection and upon reinfection. According to the "host trait variation" hypothesis, host heterogeneity effects would be consistent across parasite species. Supporting this hypothesis, both bacterial pathogens exhibited reduced performance in G. gerbillus compared to the other rodent species. However, consistent with the alternative "specific host-parasite interaction" hypothesis, all other aspects of the infection dynamics of these two pathogens exhibited varying trends across the three hosts, indicating the uniqueness of each pathogen-host interaction. Our findings support the notion that the variability in infection dynamics is not solely attributable to host heterogeneity, but rather emerges from the interplay between specific host characteristics and parasite traits. We discuss potential directions for future research to deepen our understanding of within-host dynamics in multispecies communities. We stress the necessity of analyzing each distinct host-parasite interaction independently when making inferences about community patterns based on infection dynamics within hosts until more experimental data on natural systems are accumulated.
宿主物种间感染动态的差异会深刻影响寄生虫的流行病学、生态学和进化。然而，由于涉及多个宿主和多个寄生虫物种以捕捉宿主体内完整感染动态的实验很少，不同寄生虫物种间宿主异质性效应的潜在机制在很大程度上仍不为人知。我们使用一个模型系统剖析了宿主和病原体效应在塑造宿主体内感染动态中的具体作用，该模型系统包括来自以色列内盖夫沙漠西北部的三种共存啮齿动物物种及其主要细菌病原体克氏巴尔通体A2和类血支原体。为了测试宿主物种异质性对寄生虫动态的影响主要是源于宿主特征变异（“宿主特征变异假说”）还是反映了独特的宿主 - 寄生虫相互作用（“特定宿主 - 寄生虫相互作用假说”），我们用巴尔通体或支原体接种了这三种物种（安德森更格卢鼠、金字塔更格卢鼠和格氏更格卢鼠）的啮齿动物，并比较了它们在初次感染和再次感染期间的感染动态。根据“宿主特征变异”假说，宿主异质性效应在不同寄生虫物种间应是一致的。支持这一假说的是，与其他啮齿动物物种相比，两种细菌病原体在格氏更格卢鼠中的表现均有所下降。然而，与另一种“特定宿主 - 寄生虫相互作用”假说一致的是，这两种病原体感染动态的所有其他方面在三种宿主中呈现出不同的趋势，表明每种病原体 - 宿主相互作用的独特性。我们的研究结果支持这样一种观点，即感染动态的变异性并非仅归因于宿主异质性，而是源于特定宿主特征与寄生虫特征之间的相互作用。我们讨论了未来研究的潜在方向，以加深我们对多物种群落中宿主体内动态的理解。我们强调，在基于宿主体内感染动态推断群落模式时，在积累更多关于自然系统的实验数据之前，有必要独立分析每种独特的宿主 - 寄生虫相互作用。
