Short-term and long-term consequences of avian malaria-like infection

禽类疟疾感染的短期和长期后果

• 批准号: 398434413
• 负责人: Dr. Nayden Chakarov
• 金额: --
• 依托单位: Arbeitsgruppe Verhaltensforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398434413?language=en
• 关键词: Short; term; long; consequences; avian

Parasites and pathogens cause and maintain a great diversity of defence mechanisms of their hosts, both on the levels of individual physiology and population-wide evolution. Defences can be separated in two large fractions – resistance and tolerance, but the mechanisms of tolerance are poorly understood, especially for the wide variety or wildlife infections which are not very obviously harming their hosts. Particularly low parasite virulence and high host tolerance are expected to evolve for early, vertically and quasi-vertically transmitted infections, which have the life-history features of childhood diseases. A prominent example are malaria-like parasites, which infect and shape the life-histories of many wild mammalian, lizard and bird hosts. For these parasites, the timing of infection, and the different outcomes of the host-parasite co-evolution have not been explored to their physiological expression, and the costs of infection to the hosts are unknown. This proposal aims to explore all these aspects in one wildlife model system and quantify the short-term effects of malaria-like infections on the physiology and transcriptome profiles of wild raptor nestlings, as well as the long-term effects of the infection on survival and recruitment. This will be achieved on the basis of a long-term field study, which has been sampling all nestlings in a population of common buzzards (Buteo buteo) for the last 14 years and where 44% of all nestlings are infected by the malaria-related parasite Leucocytozoon buteonis. Although most nestlings are already infected with Leucocytozoon at an early age, there is no obvious disease-caused mortality. The physiological and long-term costs of the infection will be quantified via experimental treatment of groups of infected nestlings with antimalarial drugs, following their development and quantifying their physiological and transcriptomic profile until fledging. The effects of infection may additionally depend on the host phenotype, and on environmental conditions such as nutritional stress. Therefore the synergistic effects of Leucocytozoon infection with buzzard plumage morph and prey availability will be analysed in separate infection-relief experiments. The transcriptome profiles of infected, compared to non-infected and treated hosts, will show the individual ratio of tolerance to resistance in the response to the parasite. By the end of the study period the cumulative sample of infected and infection-relieved wing-tagged nestlings will deliver sufficient data for analysis of infection-dependent long-term survival. This study on malaria-like infections of raptor nestling gives the unique opportunity to empirically show the effects of coevolved childhood diseases on host tolerance and parasite virulence.

寄生虫和病原体在个体生理学和群体进化水平上引起并维持其宿主多种多样的防御机制。防御可以分为两大部分——抵抗和耐受，但人们对耐受机制知之甚少，特别是对于种类繁多的野生动物感染，这些感染对宿主的伤害并不明显。早期、垂直和准垂直传播的感染预计会进化出特别低的寄生虫毒力和高宿主耐受性，这些感染具有儿童疾病的生活史特征。 一个突出的例子是类疟疾寄生虫，它感染并影响许多野生哺乳动物、蜥蜴和鸟类宿主的生活史。对于这些寄生虫，感染的时间以及宿主-寄生虫共同进化的不同结果尚未对其生理表达进行探索，并且宿主感染的成本尚不清楚。该提案旨在在一个野生动物模型系统中探索所有这些方面，并量化类疟疾感染对野生猛禽雏鸟生理和转录组特征的短期影响，以及感染对生存和招募的长期影响。这一目标将在一项长期实地研究的基础上实现，该研究在过去 14 年里对普通鵟 (Buteo buteo) 种群中的所有雏鸟进行了采样，其中 44% 的雏鸟受到与疟疾相关的寄生虫白细胞虫 (Leucocytozoon buteonis) 的感染。尽管大多数雏鸟在很小的时候就已经感染了白细胞虫，但没有明显的疾病引起的死亡。感染的生理和长期成本将通过用抗疟药物对受感染的雏鸟进行实验性治疗来量化，跟踪它们的发育并量化它们的生理和转录组特征，直到长出羽毛。感染的影响可能还取决于宿主表型以及营养应激等环境条件。因此，白细胞虫感染与秃鹰羽毛变形和猎物可用性的协同效应将在单独的感染缓解实验中进行分析。与未感染和治疗的宿主相比，感染者的转录组图谱将显示个体对寄生虫反应的耐受性与耐药性的比率。到研究期结束时，受感染和感染缓解的翼标记雏鸟的累积样本将为分析感染依赖性长期生存提供足够的数据。这项针对猛禽雏鸟的疟疾样感染的研究为凭经验展示共同进化的儿童疾病对宿主耐受性和寄生虫毒力的影响提供了独特的机会。