Data from: Competing for blood: the ecology of parasite resource competition in human malaria-helminth co-infections

Ecological theory suggests that co-infecting parasite species can interact within hosts directly, via host immunity and/or via resource competition. In mice, competition for red blood cells (RBCs) between malaria and bloodsucking helminths can regulate malaria population dynamics, but the importance of RBC competition in human hosts was unknown. We analyzed infection density (i.e. the concentration of parasites in infected hosts), from a 2-year deworming study of over 4,000 human subjects. After accounting for resource-use differences among parasites, we find evidence of resource competition, priority effects, and a competitive hierarchy within co-infected individuals. For example, reducing competition via deworming increased Plasmodium vivax densities 2.8-fold, and this effect is limited to bloodsucking hookworms. Our ecological, resource-based perspective sheds new light into decades of conflicting outcomes of malaria-helminth co-infection studies with significant health and transmission consequences. Beyond blood, investigating within-human resource competition may bring new insights for improving human health.

生态学理论表明，共感染的寄生虫物种可在宿主体内通过直接互作、宿主免疫介导或资源竞争三种途径发生相互作用。在小鼠模型中，疟原虫与吸血蠕虫之间针对红细胞（red blood cells, RBCs）的竞争可调控疟原虫的种群动态，但红细胞竞争在人类宿主中的重要性此前尚未明确。本研究基于一项纳入超过4000名人类受试者、为期两年的驱虫干预研究，对感染密度（即受感染宿主体内的寄生虫浓度）进行了分析。在校正不同寄生虫的资源利用差异后，我们在共感染个体中观测到资源竞争、优先效应以及竞争层级的相关证据。例如，通过驱虫降低竞争可使间日疟原虫（Plasmodium vivax）的感染密度提升2.8倍，且该效应仅见于吸血钩虫共感染场景。本研究基于生态学与资源竞争的分析视角，为数十年来疟原虫与蠕虫共感染研究中出现的诸多矛盾结果提供了全新阐释，相关发现对人类健康与疾病传播均具有重要影响。除血液系统外，探究人类宿主体内的资源竞争机制，或可为改善人类健康状况带来全新的研究思路。