Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls

SIMPLE SUMMARY: Avian haemosporidians of the genera Plasmodium, Haemoproteus, and Leucocytozoon are vector-borne blood parasites, which commonly infect birds all over the world, except for Antarctica. Although called blood parasites, these pathogens develop not only in the blood cells of vertebrate...

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Autores principales: Ilgūnas, Mikas, Himmel, Tanja, Harl, Josef, Dagys, Mindaugas, Valkiūnas, Gediminas, Weissenböck, Herbert
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9454416/
https://www.ncbi.nlm.nih.gov/pubmed/36077935
http://dx.doi.org/10.3390/ani12172212
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author Ilgūnas, Mikas
Himmel, Tanja
Harl, Josef
Dagys, Mindaugas
Valkiūnas, Gediminas
Weissenböck, Herbert
author_facet Ilgūnas, Mikas
Himmel, Tanja
Harl, Josef
Dagys, Mindaugas
Valkiūnas, Gediminas
Weissenböck, Herbert
author_sort Ilgūnas, Mikas
collection PubMed
description SIMPLE SUMMARY: Avian haemosporidians of the genera Plasmodium, Haemoproteus, and Leucocytozoon are vector-borne blood parasites, which commonly infect birds all over the world, except for Antarctica. Although called blood parasites, these pathogens develop not only in the blood cells of vertebrate hosts, but also in the tissues of various organs. While the blood stages have been studied quite intensively, the tissue stages, patterns of their development, and their effect on the vertebrate host are not well understood, especially in wild, non-passerine birds. The present study aimed at gaining new knowledge about avian haemosporidian parasites naturally infecting owls in Austria and Lithuania. Organ samples of 121 owls were investigated for blood parasites using molecular and histological methods. Over 70% of the owls were infected, revealing seven new genetic variants (lineages) of avian haemosporidian parasites. Tissue stages of Leucocytozoon spp. and Haemoproteus syrnii, a common parasite in owls, were discovered, providing new insights into the parasites’ tissue development. This study contributes new knowledge to a better understanding of the biodiversity and life cycles of avian haemosporidian parasites. These data are crucial for avian medicine and bird protection and indicate directions for further research on the tissue development of haemosporidian infections. ABSTRACT: Avian haemosporidian parasites (Haemosporida, Apicomplexa) are globally distributed and infect birds of many orders. These pathogens have been much investigated in domestic and wild passeriform birds, in which they are relatively easy to access. In birds belonging to other orders, including owls (order Strigiformes), these parasites have been studied fragmentarily. Particularly little is known about the exo-erythrocytic development of avian haemosporidians. The goal of this study was to gain new knowledge about the parasites infecting owls in Europe and investigate their exo-erythrocytic stages. Tissue samples of 121 deceased owls were collected in Austria and Lithuania, and examined using polymerase chain reactions (PCR), histology, and chromogenic in situ hybridization (CISH). PCR-based diagnostics showed a total prevalence of 73.6%, revealing two previously unreported Haemoproteus and five novel Leucocytozoon lineages. By CISH and histology, meronts of several Leucocytozoon lineages (lASOT06, lSTAL5, lSTAL7) were discovered in the brains, heart muscles, and kidneys of infected birds. Further, megalomeronts of Haemoproteus syrnii (lineage hSTAL2) were discovered. This study contributes new knowledge to a better understanding of the biodiversity of avian haemosporidian parasites infecting owls in Europe, provides information on tissue stages of the parasites, and calls for further research of these under-investigated pathogens relevant to bird health.
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spelling pubmed-94544162022-09-09 Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls Ilgūnas, Mikas Himmel, Tanja Harl, Josef Dagys, Mindaugas Valkiūnas, Gediminas Weissenböck, Herbert Animals (Basel) Article SIMPLE SUMMARY: Avian haemosporidians of the genera Plasmodium, Haemoproteus, and Leucocytozoon are vector-borne blood parasites, which commonly infect birds all over the world, except for Antarctica. Although called blood parasites, these pathogens develop not only in the blood cells of vertebrate hosts, but also in the tissues of various organs. While the blood stages have been studied quite intensively, the tissue stages, patterns of their development, and their effect on the vertebrate host are not well understood, especially in wild, non-passerine birds. The present study aimed at gaining new knowledge about avian haemosporidian parasites naturally infecting owls in Austria and Lithuania. Organ samples of 121 owls were investigated for blood parasites using molecular and histological methods. Over 70% of the owls were infected, revealing seven new genetic variants (lineages) of avian haemosporidian parasites. Tissue stages of Leucocytozoon spp. and Haemoproteus syrnii, a common parasite in owls, were discovered, providing new insights into the parasites’ tissue development. This study contributes new knowledge to a better understanding of the biodiversity and life cycles of avian haemosporidian parasites. These data are crucial for avian medicine and bird protection and indicate directions for further research on the tissue development of haemosporidian infections. ABSTRACT: Avian haemosporidian parasites (Haemosporida, Apicomplexa) are globally distributed and infect birds of many orders. These pathogens have been much investigated in domestic and wild passeriform birds, in which they are relatively easy to access. In birds belonging to other orders, including owls (order Strigiformes), these parasites have been studied fragmentarily. Particularly little is known about the exo-erythrocytic development of avian haemosporidians. The goal of this study was to gain new knowledge about the parasites infecting owls in Europe and investigate their exo-erythrocytic stages. Tissue samples of 121 deceased owls were collected in Austria and Lithuania, and examined using polymerase chain reactions (PCR), histology, and chromogenic in situ hybridization (CISH). PCR-based diagnostics showed a total prevalence of 73.6%, revealing two previously unreported Haemoproteus and five novel Leucocytozoon lineages. By CISH and histology, meronts of several Leucocytozoon lineages (lASOT06, lSTAL5, lSTAL7) were discovered in the brains, heart muscles, and kidneys of infected birds. Further, megalomeronts of Haemoproteus syrnii (lineage hSTAL2) were discovered. This study contributes new knowledge to a better understanding of the biodiversity of avian haemosporidian parasites infecting owls in Europe, provides information on tissue stages of the parasites, and calls for further research of these under-investigated pathogens relevant to bird health. MDPI 2022-08-28 /pmc/articles/PMC9454416/ /pubmed/36077935 http://dx.doi.org/10.3390/ani12172212 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ilgūnas, Mikas
Himmel, Tanja
Harl, Josef
Dagys, Mindaugas
Valkiūnas, Gediminas
Weissenböck, Herbert
Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls
title Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls
title_full Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls
title_fullStr Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls
title_full_unstemmed Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls
title_short Exo-Erythrocytic Development of Avian Haemosporidian Parasites in European Owls
title_sort exo-erythrocytic development of avian haemosporidian parasites in european owls
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9454416/
https://www.ncbi.nlm.nih.gov/pubmed/36077935
http://dx.doi.org/10.3390/ani12172212
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