title: Age-specific haemosporidian infection dynamics and survival in Seychelles warblers.
abstract: Parasites may severely impact the fitness and life-history of their hosts. After infection, surviving individuals may suppress the growth of the parasite, or completely clear the infection and develop immunity. Consequently, parasite prevalence is predicted to decline with age. Among elderly individuals, immunosenescence may lead to a late-life increase in infection prevalence. We used a 21-year longitudinal dataset from one population of individually-marked Seychelles warblers (Acrocephalus sechellensis) to investigate age-dependent prevalence of the GRW1 strain of the intracellular protozoan blood parasite Haemoproteus nucleocondensus and whether infections with this parasite affect age-dependent survival. We analyzed 2454 samples from 1431 individuals and found that H. nucleocondensus infections could rarely be detected in nestlings. Prevalence increased strongly among fledglings and peaked among older first year birds. Prevalence was high among younger adults and declined steeply until ca 4 years of age, after which it was stable. Contrary to expectations, H. nucleocondensus prevalence did not increase among elderly individuals and we found no evidence that annual survival was lower in individuals suffering from an infection. Our results suggest that individuals clear or suppress infections and acquire immunity against future infections, and provide no evidence for immunosenescence nor an impact of chronic infections on survival.
authors.affiliation: Behavioural and Physiological Ecology, GELIFES, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.|Theoretical Research in Evolutionary Life Sciences, GELIFES, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Hammers
authors.affiliation: Behavioural and Physiological Ecology, GELIFES, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Komdeur
authors.affiliation: Behavioural and Physiological Ecology, GELIFES, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.|Theoretical Research in Evolutionary Life Sciences, GELIFES, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.
authors.forename: Sjouke A
authors.initials: SA
authors.lastname: Kingma
authors.affiliation: Behavioural and Physiological Ecology, GELIFES, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.|School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Hutchings
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK.
authors.forename: Eleanor A
authors.initials: EA
authors.lastname: Fairfield
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK.
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Gilroy
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK.|Nature Seychelles, Roche Caiman, Mahé, Republic of Seychelles.
authors.forename: David S
authors.initials: DS
authors.lastname: Richardson
mesh_terms: D000367:Age Factors; D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000469:parasitology*; D016787:Haemosporida / Q000502:physiology*; D006790:Host-Parasite Interactions; D015995:Prevalence; D011529:Protozoan Infections, Animal / Q000453:epidemiology / Q000469:parasitology*; D012750:Seychelles / Q000453:epidemiology; D020308:Songbirds / Q000469:parasitology*; D016019:Survival Analysis; D013997:Time Factors