Biogéosciences, CNRS UMR 6282, Université de Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France.
Biogéosciences, CNRS UMR 6282, Université de Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France.
Infect Genet Evol. 2021 Mar;88:104698. doi: 10.1016/j.meegid.2020.104698. Epub 2020 Dec 25.
Once infected, hosts can rely on two strategies to cope with parasites: fight them (resist the infection) or minimize the damage they induce (tolerate the infection). While there is evidence that aging reduces resistance, how tolerance varies as hosts become old has been barely studied. Here, we used a rodent malaria parasite (Plasmodium yoelii) to investigate whether 2- and 12-month old house mice differ in their capacity to resist and tolerate the infection. We found that 12-month old mice harbored higher parasitemia, showing that age reduces resistance to malaria. Infection-induced deterioration of host health was assessed using red blood cell and body mass loss. Using both traits, the rate of decline in host health, as parasitemia increased, was more pronounced in 12- than in 2-month old mice, showing that age is also associated with impaired tolerance to malaria. Overall, resistance and tolerance positively covaried; however, this was only due to the age effect, since, within age classes, the two traits were not correlated. These results show that senescing individuals might be both more susceptible to infectious diseases and less able to cope with the damage that infection induces.
一旦感染，宿主可以依赖两种策略来应对寄生虫：与寄生虫作斗争（抵抗感染）或尽量减少寄生虫引起的损害（耐受感染）。虽然有证据表明衰老会降低抵抗力，但随着宿主衰老，其耐受能力如何变化几乎没有研究过。在这里，我们使用一种啮齿动物疟疾寄生虫（Plasmodium yoelii）来研究 2 个月和 12 个月大的家鼠在抵抗和耐受感染方面是否存在差异。我们发现 12 个月大的老鼠寄生血症更高，表明年龄会降低对疟疾的抵抗力。使用红细胞和体重损失来评估感染引起的宿主健康恶化。使用这两个特征，随着寄生虫血症的增加，宿主健康下降的速度在 12 个月大的老鼠中比 2 个月大的老鼠更为明显，表明年龄也与对疟疾的耐受能力受损有关。总的来说，抵抗力和耐受能力呈正相关；然而，这只是由于年龄的影响，因为在年龄组内，这两个特征没有相关性。这些结果表明，衰老个体可能更容易感染传染病，也更难以应对感染引起的损害。
