1
|
Martinez V, Duran EMI, Kimmitt AA, Russell KE, Jill Heatley J, Grace JK. Chronic stress increases adaptive immune response over six weeks in the house sparrow, Passer domesticus. Gen Comp Endocrinol 2024; 358:114612. [PMID: 39293532 DOI: 10.1016/j.ygcen.2024.114612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 09/04/2024] [Accepted: 09/13/2024] [Indexed: 09/20/2024]
Abstract
The vertebrate stress response enables an organism to shift energy towards activities that promote immediate survival when facing a threat to homeostasis, but it can also have detrimental effects on organismal health. Acute and chronic stressors generally have contrasting effects on immune responses, but the timeline of this transition between acute and chronic stressors and their effects on immune responses remains unclear. In this study, we investigate changes in immune markers in captive house sparrows (Passer domesticus) after exposure to normal laboratory conditions, an acute stressor, and chronic stressors for 42 days. Specifically, we examined changes in baseline and stress-induced corticosterone concentrations, body condition, heterophil/lymphocyte (H:L) ratio, hemolysis-hemagglutination, and wound healing. We found that individuals exposed to a single acute stressor had significantly higher stress-induced corticosterone concentrations 24 h after stressor exposure, however this effect was reversed after 48 h. Chronic stressor exposure resulted in generally stronger adaptive immune responses, demonstrated by higher baseline and stress-induced lysis, higher baseline hemagglutination, and slower wound healing. Within-trait correlations also increased with chronic stressor exposure, suggesting limitations on phenotypic plasticity. Most of the effects of chronic stressor exposure on immune markers strengthened over the 42 days of the experiment and differences between captivity-only and treatment groups were not apparent until approximately 20 days of chronic stressor exposure. These results highlight the importance of stressor duration in understanding the effects of chronic stressor exposure on immune responses.
Collapse
Affiliation(s)
- Viridiana Martinez
- Dept. of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA
| | - Elena M I Duran
- Interdisciplinary Doctoral Degree Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA
| | - Abigail A Kimmitt
- Dept. of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA; Dept. of Biology, Hofstra University, Hempstead, NY 11549, USA
| | - Karen E Russell
- Dept. of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA
| | - J Jill Heatley
- Dept. of Small Animal Clinical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Jacquelyn K Grace
- Dept. of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA; Interdisciplinary Doctoral Degree Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA.
| |
Collapse
|
2
|
Sheta B, Waheed O, Ayad E, Habbak L, Hyder A. Constitutive immunity is influenced by avian influenza virus-induced modification of gut microbiota in Eurasian teal (Anas crecca). Comp Biochem Physiol C Toxicol Pharmacol 2024; 278:109867. [PMID: 38373511 DOI: 10.1016/j.cbpc.2024.109867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 02/21/2024]
Abstract
Understanding the dynamics of migrant birds' gut microbial communities is essential for evaluating their ecological interactions, since these birds act as vectors for zoonotic viruses and their gut microbiome may have exceptional relationship with zoonotic viral infection. The Eurasian teal duck Anas crecca traverses continents during migration, combining and providing intercontinental links for avian influenza viruses (AIV) of different origins. The present study aimed to investigate how the AIV infection affects gut microbial composition and evaluate the consequent physiological stress and constitutive immunity of teal birds. Samples were collected from 2 flocks during their migratory stopover in northern Egypt. An important shift in gut microbiota of AIV-infected individuals has been detected by RT-PCR. In healthy teal, firmicutes dominated followed by proteobacteria, while the structure was reversed in infected birds. Infection with AIV significantly increased the stress hormone corticosterone, accompanied by a significant increase in both oxidative stress markers and antioxidants. Constitutive immunity, measured by plasma bactericidal effect against E. coli, the nonspecific natural antibodies, and the mediated complement activation, was reduced in AIV-infected teal birds. Constitutive immunity parameters were proportionally correlated to the firmicutes and inversely to the proteobacteria abundances, but not to the viral positivity. In conclusion, the present study provides initial evidence of the alteration of the gut microbiome in the Eurasian teal Anas crecca by AIV infection and demonstrates that the AIV-induced reduction in constitutive immunity is a consequence of the shift in microbiome composition rather than the virus infection itself or its induced stress.
Collapse
Affiliation(s)
- Basma Sheta
- Zoology Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Omnia Waheed
- Zoology Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Esraa Ayad
- Zoology Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Lotfy Habbak
- Zoology Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Ayman Hyder
- Zoology Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt.
| |
Collapse
|
3
|
Sánchez KL, Baird JK, Nielsen A, Nurillah A, Agustina F, Komara, Fadilah F, Prameswari W, Nugraha RTP, Saputra S, Nurkanto A, Dharmayanthi AB, Pratama R, Exploitasia I, Greenwood AD. Naturally acquired immunity to Plasmodium pitheci in Bornean orangutans ( Pongo pygmaeus). Parasitology 2024; 151:380-389. [PMID: 38361461 PMCID: PMC11044065 DOI: 10.1017/s0031182024000155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 01/17/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024]
Abstract
Naturally acquired immunity to the different types of malaria in humans occurs in areas of endemic transmission and results in asymptomatic infection of peripheral blood. The current study examined the possibility of naturally acquired immunity in Bornean orangutans, Pongo pygmaeus, exposed to endemic Plasmodium pitheci malaria. A total of 2140 peripheral blood samples were collected between January 2017 and December 2022 from a cohort of 135 orangutans housed at a natural forested Rescue and Rehabilitation Centre in West Kalimantan, Indonesia. Each individual was observed for an average of 4.3 years during the study period. Blood samples were examined by microscopy and polymerase chain reaction for the presence of plasmodial parasites. Infection rates and parasitaemia levels were measured among age groups and all 20 documented clinical malaria cases were reviewed to estimate the incidence of illness and risk ratios among age groups. A case group of all 17 individuals that had experienced clinical malaria and a control group of 34 individuals having an event of >2000 parasites μL−1 blood but with no outward or clinical sign of illness were studied. Immature orangutans had higher-grade and more frequent parasitaemia events, but mature individuals were more likely to suffer from clinical malaria than juveniles. The case orangutans having patent clinical malaria were 256 times more likely to have had no parasitaemia event in the prior year relative to asymptomatic control orangutans. The findings are consistent with rapidly acquired immunity to P. pitheci illness among orangutans that wanes without re-exposure to the pathogen.
Collapse
Affiliation(s)
- Karmele Llano Sánchez
- IAR Indonesia Foundation, Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Sinarwangi, Bogor, West Java, Indonesia
- International Animal Rescue, Uckfield, UK
- School of Veterinary Medicine, Freie Universität, Berlin, Germany
| | - John Kevin Baird
- Oxford University Clinical Research Unit-Indonesia, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Aileen Nielsen
- Center for Law and Economics, ETH Zurich, Zurich, Switzerland
| | - Andini Nurillah
- IAR Indonesia Foundation, Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Sinarwangi, Bogor, West Java, Indonesia
| | - Fitria Agustina
- IAR Indonesia Foundation, Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Sinarwangi, Bogor, West Java, Indonesia
| | - Komara
- IAR Indonesia Foundation, Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Sinarwangi, Bogor, West Java, Indonesia
| | - Fina Fadilah
- IAR Indonesia Foundation, Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Sinarwangi, Bogor, West Java, Indonesia
| | - Wendi Prameswari
- IAR Indonesia Foundation, Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Sinarwangi, Bogor, West Java, Indonesia
| | | | - Sugiyono Saputra
- Research Center for Applied Zoology, National Research and Innovation Agency (BRIN), Jakarta, Indonesia
| | - Arif Nurkanto
- Research Center for Biosystematics and Evolution, National Research and Innovation Agency (BRIN), Jakarta, Indonesia
| | - Anik Budhi Dharmayanthi
- Research Center for Biosystematics and Evolution, National Research and Innovation Agency (BRIN), Jakarta, Indonesia
| | - Rahadian Pratama
- Center for Biomedical Research, Research Organization for Health, National Research and Innovation Agency (BRIN), Jakarta, Indonesia
| | - Indra Exploitasia
- Biodiversity Conservation Directorate of the General Director of Natural Resources and Ecosystem Conservation, Ministry of Environment and Forestry of the Republic of Indonesia, Jakarta, Indonesia
| | - Alex D. Greenwood
- School of Veterinary Medicine, Freie Universität, Berlin, Germany
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| |
Collapse
|
4
|
Sheppard EC, Martin CA, Armstrong C, González-Quevedo C, Illera JC, Suh A, Spurgin LG, Richardson DS. Genotype-environment associations reveal genes potentially linked to avian malaria infection in populations of an endemic island bird. Mol Ecol 2024; 33:e17329. [PMID: 38533805 DOI: 10.1111/mec.17329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 01/29/2024] [Accepted: 03/01/2024] [Indexed: 03/28/2024]
Abstract
Patterns of pathogen prevalence are, at least partially, the result of coevolutionary host-pathogen interactions. Thus, exploring the distribution of host genetic variation in relation to infection by a pathogen within and across populations can provide important insights into mechanisms of host defence and adaptation. Here, we use a landscape genomics approach (Bayenv) in conjunction with genome-wide data (ddRADseq) to test for associations between avian malaria (Plasmodium) prevalence and host genetic variation across 13 populations of the island endemic Berthelot's pipit (Anthus berthelotii). Considerable and consistent spatial heterogeneity in malaria prevalence was observed among populations over a period of 15 years. The prevalence of malaria infection was also strongly positively correlated with pox (Avipoxvirus) prevalence. Multiple host loci showed significant associations with malaria prevalence after controlling for genome-wide neutral genetic structure. These sites were located near to or within genes linked to metabolism, stress response, transcriptional regulation, complement activity and the inflammatory response, many previously implicated in vertebrate responses to malarial infection. Our findings identify diverse genes - not just limited to the immune system - that may be involved in host protection against malaria and suggest that spatially variable pathogen pressure may be an important evolutionary driver of genetic divergence among wild animal populations, such as Berthelot's pipit. Furthermore, our data indicate that spatio-temporal variation in multiple different pathogens (e.g. malaria and pox in this case) may have to be studied together to develop a more holistic understanding of host pathogen-mediated evolution.
Collapse
Affiliation(s)
| | - Claudia A Martin
- School of Biological Sciences, University of East Anglia, Norfolk, UK
- Terrestrial Ecology Unit, Biology Department, Ghent University, Ghent, Belgium
| | - Claire Armstrong
- School of Biological Sciences, University of East Anglia, Norfolk, UK
| | - Catalina González-Quevedo
- School of Biological Sciences, University of East Anglia, Norfolk, UK
- Grupo Ecología y Evolución de Vertebrados, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Medellin, Colombia
| | - Juan Carlos Illera
- Biodiversity Research Institute (CSIC-Oviedo, University-Principality of Asturias), University of Oviedo, Mieres, Asturias, Spain
| | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norfolk, UK
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Bonn, Germany
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Lewis G Spurgin
- School of Biological Sciences, University of East Anglia, Norfolk, UK
| | | |
Collapse
|
5
|
Reinoso-Pérez MT, Dhondt KV, Dulcet H, Katzenstein N, Sydenstricker AV, Dhondt AA. Seasonal Variation in Detection of Haemosporidia in a Bird Community: A Comparison of Nested PCR and Microscopy. J Wildl Dis 2024; 60:105-115. [PMID: 37909407 DOI: 10.7589/jwd-d-23-00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 07/18/2023] [Indexed: 11/03/2023]
Abstract
In a 2-yr study on prevalence of Haemosporidia in an avian community in Ithaca, New York, USA, we tested the hypothesis that apparent seasonal variation in prevalence is influenced by the detection protocol. We confirmed a higher detection of Haemosporidia using a molecular diagnosis technique (PCR) than by microscopy; this further increased when the PCR test was triplicated. Microscopic examination and PCR techniques have different specificity and sensitivity and therefore different probabilities of detecting hemoparasites. Birds with chronic infections or sampled during winter often have very low parasitemia, and such infections may be missed by microscopy but detected by PCR. Haemosporidian prevalence was higher during the breeding season than during the nonbreeding season regardless of the method used. Detection of Leucocytozoon spp. infection from blood smears using microscopy was challenging.
Collapse
Affiliation(s)
- María Teresa Reinoso-Pérez
- Department of Natural Resources and the Environment, Fernow Hall, 226 Mann Dr., Cornell University, Ithaca, New York 14853, USA
- Laboratory of Ornithology, 59 Sapsucker Woods Rd., Cornell University, Ithaca, New York, 14853, USA
| | - Keila V Dhondt
- Department of Microbiology and Immunology, College of Veterinary Medicine, 602 Tower Rd., Cornell University, Ithaca, New York 14853, USA
| | - Holland Dulcet
- College of Veterinary Medicine, 602 Tower Rd., Cornell University, Ithaca, New York 14853, USA
- Present address: Westfield Veterinary Group, 562 Springfield Ave., Westfield, New Jersey 07090, USA
| | - Nina Katzenstein
- College of Veterinary Medicine, 602 Tower Rd., Cornell University, Ithaca, New York 14853, USA
| | - Agnes V Sydenstricker
- Department of Integrative Neurosciences, no. 230B, Binghamton University, Binghamton, New York 13902, USA
- Present address: Microbiology & Immunology Department, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York 10461, USA
| | - André A Dhondt
- Department of Ecology and Evolutionary Biology, Corson/Mudd Hall, 215 Tower Rd., Cornell University, Ithaca, New York 14853, USA
- Laboratory of Ornithology, 59 Sapsucker Woods Rd., Cornell University, Ithaca, New York, 14853, USA
| |
Collapse
|
6
|
Kelly TR, Cannon AL, Stansberry KR, Kimball MG, Lattin CR. Changes in hypothalamic-pituitary-adrenal axis function, immunity, and glucose during acute Plasmodium relictum infection in house sparrows (Passer domesticus). Gen Comp Endocrinol 2024; 345:114388. [PMID: 37802425 DOI: 10.1016/j.ygcen.2023.114388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 10/02/2023] [Indexed: 10/10/2023]
Abstract
Hosts of the same species vary in physiological responses to the same parasite, and some groups of individuals can disproportionately affect disease dynamics; however, the underlying pathophysiology of host-parasite interactions is poorly understood in wildlife. We tested the hypothesis that the hypothalamic-pituitary-adrenal (HPA) axis mediates host resistance and tolerance to avian malaria during the acute phase of infection by evaluating whether individual variation in circulating glucocorticoids predicted resistance to avian malaria in a songbird. We experimentally inoculated wild-caught house sparrows (Passer domesticus) with naturally sourced Plasmodium relictum and quantified baseline and restraint-induced circulating corticosterone, negative feedback ability, cellular and humoral immune function, and baseline and restraint-induced glycemia, prior to and during acute malaria infection. During peak parasitemia, we also evaluated the expression of several liver cytokines that are established pathological hallmarks of malaria in mammals: two pro-inflammatory (IFN-γ and TNF-α) and two anti-inflammatory (IL-10 and TGF-β). Although most of the host metrics we evaluated were not correlated with host resistance or tolerance to avian malaria, this experiment revealed novel relationships between malarial parasites and the avian immune system that further our understanding of the pathology of malaria infection in birds. Specifically, we found that: (1) TNF-α liver expression was positively correlated with parasitemia; (2) sparrows exhibited an anti-inflammatory profile during malaria infection; and (3) IFN-γ and circulating glucose were associated with several immune parameters, but only in infected sparrows. We also found that, during the acute phase of infection, sparrows increased the strength of corticosterone negative feedback at the level of the pituitary. In the context of our results, we discuss future methodological considerations and aspects of host physiology that may confer resistance to avian malaria, which can help inform conservation and rehabilitation strategies for avifauna at risk.
Collapse
Affiliation(s)
- T R Kelly
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - A L Cannon
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - K R Stansberry
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - M G Kimball
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - C R Lattin
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| |
Collapse
|
7
|
Ramírez-Otarola N, Maldonado K, Valdés-Ferranty F, Newsome SD, Sabat P. Seasonal changes in diet, immune function, and oxidative stress in three passerines inhabiting a Mediterranean climate. Oecologia 2023; 203:395-405. [PMID: 37950102 DOI: 10.1007/s00442-023-05474-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 10/31/2023] [Indexed: 11/12/2023]
Abstract
Oxidative status and immune function are energy-demanding traits closely linked to diet composition, particularly resource availability and nutritional value. In seasonal environments, nutrient availability and diet quality fluctuate, potentially influencing these traits. However, limited evidence exists regarding these dietary effects on immune function in seasonal environments. In this study, we employed stable isotope analysis to assess the impact of seasonal changes in niche width and trophic level (i.e., δ15N) on two immune variables (hemolysis and hemagglutination scores) and two oxidative status parameters (lipid peroxidation and total antioxidant capacity) in three passerine species: Zonotrichia capensis (omnivorous), Troglodytes aedon (insectivorous), and Spinus barbatus (granivorous). We found that hemolysis scores varied seasonally in Z. capensis, with higher values in winter compared to summer. Total antioxidant capacity (TAC) also increased during the winter in Z. capensis and S. barbatus. The isotopic niche width for Z. capensis and S. barbatus was smaller in winter than in summer, with the omnivorous species exhibiting a decrease in δ15N. Despite the seasonal shifts in ecological and physiological traits in Z. capensis, we identified no correlation between immune response and TAC with trophic level. In contrast, in the granivorous S. barbatus, the lower trophic level resulted in an increase in TAC without affecting immunity. Our findings revealed that dietary shifts do not uniformly impact oxidative status and immune function across bird species, highlighting species-specific responses to seasonal changes. This underscores the importance of integrating ecological and evolutionary perspectives when examining how diet shapes avian immunity and oxidative balance.
Collapse
Affiliation(s)
- Natalia Ramírez-Otarola
- Escuela de Medicina Veterinaria, Facultad de Medicina y Ciencias de la Salud, Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago, Chile.
| | - Karin Maldonado
- Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Santiago, Chile
| | - Fernanda Valdés-Ferranty
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Pablo Sabat
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| |
Collapse
|
8
|
Names GR, Schultz EM, Krause JS, Hahn TP, Wingfield JC, Heal M, Cornelius JM, Klasing KC, Hunt KE. Stress in paradise: effects of elevated corticosterone on immunity and avian malaria resilience in a Hawaiian passerine. J Exp Biol 2021; 224:272529. [PMID: 34553762 PMCID: PMC8546672 DOI: 10.1242/jeb.242951] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/20/2021] [Indexed: 11/20/2022]
Abstract
Vertebrates confronted with challenging environments often experience an increase in circulating glucocorticoids, which result in morphological, physiological and behavioral changes that promote survival. However, chronically elevated glucocorticoids can suppress immunity, which may increase susceptibility to disease. Since the introduction of avian malaria to Hawaii a century ago, low-elevation populations of Hawaii Amakihi (Chlorodrepanis virens) have undergone strong selection by avian malaria and evolved increased resilience (the ability to recover from infection), while populations at high elevation with few vectors have not undergone selection and remain susceptible. We investigated how experimentally elevated corticosterone affects the ability of high- and low-elevation male Amakihi to cope with avian malaria by measuring innate immunity, hematocrit and malaria parasitemia. Corticosterone implants resulted in a decrease in hematocrit in high- and low-elevation birds but no changes to circulating natural antibodies or leukocytes. Overall, leukocyte count was higher in low- than in high-elevation birds. Malaria infections were detected in a subset of low-elevation birds. Infected individuals with corticosterone implants experienced a significant increase in circulating malaria parasites while untreated infected birds did not. Our results suggest that Amakihi innate immunity measured by natural antibodies and leukocytes is not sensitive to changes in corticosterone, and that high circulating corticosterone may reduce the ability of Amakihi to cope with infection via its effects on hematocrit and malaria parasite load. Understanding how glucocorticoids influence a host's ability to cope with introduced diseases provides new insight into the conservation of animals threatened by novel pathogens. Summary: Amakihi innate immunity, as measured by natural antibodies and leukocytes, is not sensitive to changes in corticosterone, but high circulating corticosterone may reduce the ability of Amakihi to cope with avian malaria infection via its effects on hematocrit and malaria parasite load.
Collapse
Affiliation(s)
- Gabrielle R Names
- Animal Behavior Graduate Group, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.,Department of Neurobiology, Physiology and Behavior, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Elizabeth M Schultz
- Department of Biology, Wittenberg University, 200 W Ward Street, Springfield, OH 45504, USA
| | - Jesse S Krause
- Department of Biology, University of Nevada Reno, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Thomas P Hahn
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Molly Heal
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Jamie M Cornelius
- Department of Integrative Biology, Oregon State University, 2701 SW Campus Way, Corvallis, OR 97331, USA
| | - Kirk C Klasing
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kathleen E Hunt
- Smithsonian-Mason School of Conservation & Department of Biology, George Mason University, 1500 Remount Rd, Front Royal, VA 22630, USA
| |
Collapse
|