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

Andrea K. Townsend, Sarah S. Wheeler, David Freund, Ravinder N.M. Sehgal, Walter M Boyce

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)8779-8790
Number of pages12
JournalEcology and Evolution
Volume8
Issue number17
DOIs
StatePublished - Sep 1 2018

Fingerprint

Corvus brachyrhynchos
hemoparasite
blood chemistry
nestling
blood
parasites
Plasmodium
infection
hematocrit
crows
fledging
immune response
blood proteins
Leucocytozoon
plasma
protein
anemia
pathogenicity
passerine
coevolution

Keywords

  • acute infection
  • avian health parameters
  • avian malaria
  • ecoimmunology
  • immunocompetence
  • pathogenicity

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

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.

In: Ecology and Evolution, Vol. 8, No. 17, 01.09.2018, p. 8779-8790.

Research output: Contribution to journalArticle

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. In: Ecology and Evolution. 2018 ; Vol. 8, No. 17. pp. 8779-8790.
@article{62f01df375bb415eabc0b7d795b392c7,
title = "Links between blood parasites, blood chemistry, and the survival of nestling American crows",
abstract = "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.",
keywords = "acute infection, avian health parameters, avian malaria, ecoimmunology, immunocompetence, pathogenicity",
author = "Townsend, {Andrea K.} and Wheeler, {Sarah S.} and David Freund and Sehgal, {Ravinder N.M.} and Boyce, {Walter M}",
year = "2018",
month = "9",
day = "1",
doi = "10.1002/ece3.4287",
language = "English (US)",
volume = "8",
pages = "8779--8790",
journal = "Ecology and Evolution",
issn = "2045-7758",
publisher = "John Wiley and Sons Ltd",
number = "17",

}

TY - JOUR

T1 - Links between blood parasites, blood chemistry, and the survival of nestling American crows

AU - Townsend, Andrea K.

AU - Wheeler, Sarah S.

AU - Freund, David

AU - Sehgal, Ravinder N.M.

AU - Boyce, Walter M

PY - 2018/9/1

Y1 - 2018/9/1

N2 - 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.

AB - 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.

KW - acute infection

KW - avian health parameters

KW - avian malaria

KW - ecoimmunology

KW - immunocompetence

KW - pathogenicity

UR - http://www.scopus.com/inward/record.url?scp=85051323880&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85051323880&partnerID=8YFLogxK

U2 - 10.1002/ece3.4287

DO - 10.1002/ece3.4287

M3 - Article

AN - SCOPUS:85051323880

VL - 8

SP - 8779

EP - 8790

JO - Ecology and Evolution

JF - Ecology and Evolution

SN - 2045-7758

IS - 17

ER -