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Links between blood parasites, blood chemistry, and the survival of nestling American crows

Many studies have used the avian hemosporidians (Leucocytozoon, Plasmodium, and Hemoproteus) to test hypotheses of host–parasite co‐evolution, yet documented health and survival consequences of these blood parasites vary among studies and generalizations about their pathogenicity are debatable. In g...

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Autores principales: Townsend, Andrea K., Wheeler, Sarah S., Freund, David, Sehgal, Ravinder N. M., Boyce, Walter M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6157653/
https://www.ncbi.nlm.nih.gov/pubmed/30271545
http://dx.doi.org/10.1002/ece3.4287
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author Townsend, Andrea K.
Wheeler, Sarah S.
Freund, David
Sehgal, Ravinder N. M.
Boyce, Walter M.
author_facet Townsend, Andrea K.
Wheeler, Sarah S.
Freund, David
Sehgal, Ravinder N. M.
Boyce, Walter M.
author_sort Townsend, Andrea K.
collection PubMed
description Many studies have used the avian hemosporidians (Leucocytozoon, Plasmodium, and Hemoproteus) to test hypotheses of host–parasite co‐evolution, yet documented health and survival consequences of these blood parasites vary among studies and generalizations about their pathogenicity are debatable. In general, the negative effects of the hemosporidians are likely to be greatest during acute infections of young birds, yet most previous studies in wild passerines have examined chronic effects in adults. Here, we evaluated responses of nestling American crows (Corvus brachyrhynchos) to acute infection (prevalence and burden), as well as its short‐ and long‐term survival consequences. We used panel of nine hematological and biochemical parameters that are regularly used to evaluate the health of domestic animals, including leukocyte profiles, hematocrit, and plasma proteins. We assessed the effects of infection on survival in a mark‐recapture framework. Overall, 56% of crows (n = 321 samples) were infected by at least one of the three genera. Infections by all genera were associated with elevated plasma proteins and globulins, which could indicate an adaptive immune response. However, only Plasmodium infections were associated with low hematocrit (anemia) and lower fledging success, possibly mediated by the negative effect of low hematocrit values on body condition. Moreover, early Plasmodium infection (<40 days of age) had long‐term survival implications: it was associated with lower apparent survival probability within 3 years after fledging. These results suggest that young crows mounted an adaptive immune response to all three genera. Short‐ and long‐term pathological effects, however, were only apparent with Plasmodium infections.
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spelling pubmed-61576532018-09-29 Links between blood parasites, blood chemistry, and the survival of nestling American crows Townsend, Andrea K. Wheeler, Sarah S. Freund, David Sehgal, Ravinder N. M. Boyce, Walter M. Ecol Evol Original Research Many studies have used the avian hemosporidians (Leucocytozoon, Plasmodium, and Hemoproteus) to test hypotheses of host–parasite co‐evolution, yet documented health and survival consequences of these blood parasites vary among studies and generalizations about their pathogenicity are debatable. In general, the negative effects of the hemosporidians are likely to be greatest during acute infections of young birds, yet most previous studies in wild passerines have examined chronic effects in adults. Here, we evaluated responses of nestling American crows (Corvus brachyrhynchos) to acute infection (prevalence and burden), as well as its short‐ and long‐term survival consequences. We used panel of nine hematological and biochemical parameters that are regularly used to evaluate the health of domestic animals, including leukocyte profiles, hematocrit, and plasma proteins. We assessed the effects of infection on survival in a mark‐recapture framework. Overall, 56% of crows (n = 321 samples) were infected by at least one of the three genera. Infections by all genera were associated with elevated plasma proteins and globulins, which could indicate an adaptive immune response. However, only Plasmodium infections were associated with low hematocrit (anemia) and lower fledging success, possibly mediated by the negative effect of low hematocrit values on body condition. Moreover, early Plasmodium infection (<40 days of age) had long‐term survival implications: it was associated with lower apparent survival probability within 3 years after fledging. These results suggest that young crows mounted an adaptive immune response to all three genera. Short‐ and long‐term pathological effects, however, were only apparent with Plasmodium infections. John Wiley and Sons Inc. 2018-08-07 /pmc/articles/PMC6157653/ /pubmed/30271545 http://dx.doi.org/10.1002/ece3.4287 Text en © 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Research
Townsend, Andrea K.
Wheeler, Sarah S.
Freund, David
Sehgal, Ravinder N. M.
Boyce, Walter M.
Links between blood parasites, blood chemistry, and the survival of nestling American crows
title Links between blood parasites, blood chemistry, and the survival of nestling American crows
title_full Links between blood parasites, blood chemistry, and the survival of nestling American crows
title_fullStr Links between blood parasites, blood chemistry, and the survival of nestling American crows
title_full_unstemmed Links between blood parasites, blood chemistry, and the survival of nestling American crows
title_short Links between blood parasites, blood chemistry, and the survival of nestling American crows
title_sort links between blood parasites, blood chemistry, and the survival of nestling american crows
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6157653/
https://www.ncbi.nlm.nih.gov/pubmed/30271545
http://dx.doi.org/10.1002/ece3.4287
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