Ramiro Ricardo S, Pollitt Laura C, Mideo Nicole, Reece Sarah E
Institutes of Evolutionary Biology, and Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3JFL, UK.
Centre for Immunity, Infection & Evolution, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, EH9 3JFL, UK.
Ecol Lett. 2016 Sep;19(9):1041-50. doi: 10.1111/ele.12639. Epub 2016 Jun 30.
A major challenge in disease ecology is to understand how co-infecting parasite species interact. We manipulate in vivo resources and immunity to explain interactions between two rodent malaria parasites, Plasmodium chabaudi and P. yoelii. These species have analogous resource-use strategies to the human parasites Plasmodium falciparum and P. vivax: P. chabaudi and P. falciparum infect red blood cells (RBC) of all ages (RBC generalist); P. yoelii and P. vivax preferentially infect young RBCs (RBC specialist). We find that: (1) recent infection with the RBC generalist facilitates the RBC specialist (P. yoelii density is enhanced ~10 fold). This occurs because the RBC generalist increases availability of the RBC specialist's preferred resource; (2) co-infections with the RBC generalist and RBC specialist are highly virulent; (3) and the presence of an RBC generalist in a host population can increase the prevalence of an RBC specialist. Thus, we show that resources shape how parasite species interact and have epidemiological consequences.
疾病生态学中的一个主要挑战是了解共同感染的寄生虫物种如何相互作用。我们通过体内资源和免疫力的调控来解释两种啮齿动物疟原虫——查巴迪疟原虫和约氏疟原虫之间的相互作用。这些物种具有与人类疟原虫恶性疟原虫和间日疟原虫类似的资源利用策略：查巴迪疟原虫和恶性疟原虫感染所有年龄段的红细胞（红细胞泛嗜性）；约氏疟原虫和间日疟原虫优先感染年轻红细胞（红细胞专嗜性）。我们发现：（1）近期感染红细胞泛嗜性疟原虫会促进红细胞专嗜性疟原虫（约氏疟原虫密度提高约10倍）。这是因为红细胞泛嗜性疟原虫增加了红细胞专嗜性疟原虫偏好资源的可利用性；（2）红细胞泛嗜性疟原虫和红细胞专嗜性疟原虫的共同感染具有高致病性；（3）宿主群体中红细胞泛嗜性疟原虫的存在会增加红细胞专嗜性疟原虫的流行率。因此，我们表明资源塑造了寄生虫物种之间的相互作用方式，并产生了流行病学后果。
