The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite

Abstract Background Plasmodium elongatum (cytochrome b lineage pGRW6) is a widespread avian malaria parasite, often causing severe disease in non-adapted hosts. This parasite lineage is of global distribution however, its virulence remains insufficiently understood, particularly in wild birds. Surpr...

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Main Authors: Mikas Ilgūnas, Vaidas Palinauskas, Elena Platonova, Tatjana Iezhova, Gediminas Valkiūnas
Format: Article
Language:English
Published: BMC 2019-08-01
Series:Malaria Journal
Subjects:
Online Access:http://link.springer.com/article/10.1186/s12936-019-2926-4
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author Mikas Ilgūnas
Vaidas Palinauskas
Elena Platonova
Tatjana Iezhova
Gediminas Valkiūnas
author_facet Mikas Ilgūnas
Vaidas Palinauskas
Elena Platonova
Tatjana Iezhova
Gediminas Valkiūnas
author_sort Mikas Ilgūnas
collection DOAJ
description Abstract Background Plasmodium elongatum (cytochrome b lineage pGRW6) is a widespread avian malaria parasite, often causing severe disease in non-adapted hosts. This parasite lineage is of global distribution however, its virulence remains insufficiently understood, particularly in wild birds. Surprisingly, this infection has never been reported in Common starlings Sturnus vulgaris and Common crossbills Loxia curvirostra, common European songbirds which were extensively sampled across Europe. A hypothesis was proposed that these birds might be resistant to the pGRW6 infection. The aim of this study was to test this hypothesis. Methods Lineage pGRW6 was isolated from a naturally infected Eurasian reed warbler, multiplied in vivo and inoculated in Common starlings and Common crossbills. Experimental and control groups (8 birds in each) were maintained in controlled conditions and examined microscopically every 4 days. Haematocrit value and body mass were monitored in parallel. At the end of the experiment (44 days post exposure), samples of internal organs were collected and examined using histological methods for possible presence of phanerozoites. Results All control birds remained uninfected. Experimental starlings were resistant. All exposed crossbills were susceptible and survived until the end of this study. Prepatent period was 12–16 days post exposure. Light parasitaemia (< 0.7%) developed in all birds, and only few phanerozoites were seen in bone marrow cells of 5 of 8 experimentally infected crossbills. Significant changes were reported only in haematocrit value but not body mass in the exposed crossbills compared to controls. Conclusion Plasmodium elongatum (pGRW6) is of low virulence in Common crossbills and is unable to develop in Common starlings, indicating innate resistance of the later bird species. Low virulence in Common crossbills is likely due to the inability or low ability of this parasite lineage to develop phanerozoites resulting in light (if at all) damage of stem bone marrow cells. This study suggests that susceptibility of different bird species to the lineage pGRW6 is markedly variable. The global distribution of this parasite might be due to low virulence in wild adapted avian hosts, which survive this infection and serve as reservoirs host for non-adapted birds in whom this infection is often lethal.
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spelling doaj.art-3b201eef85144114bc119b5d206e6bd62022-12-21T17:49:47ZengBMCMalaria Journal1475-28752019-08-0118111110.1186/s12936-019-2926-4The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasiteMikas Ilgūnas0Vaidas Palinauskas1Elena Platonova2Tatjana Iezhova3Gediminas Valkiūnas4Nature Research CentreNature Research CentreNature Research CentreNature Research CentreNature Research CentreAbstract Background Plasmodium elongatum (cytochrome b lineage pGRW6) is a widespread avian malaria parasite, often causing severe disease in non-adapted hosts. This parasite lineage is of global distribution however, its virulence remains insufficiently understood, particularly in wild birds. Surprisingly, this infection has never been reported in Common starlings Sturnus vulgaris and Common crossbills Loxia curvirostra, common European songbirds which were extensively sampled across Europe. A hypothesis was proposed that these birds might be resistant to the pGRW6 infection. The aim of this study was to test this hypothesis. Methods Lineage pGRW6 was isolated from a naturally infected Eurasian reed warbler, multiplied in vivo and inoculated in Common starlings and Common crossbills. Experimental and control groups (8 birds in each) were maintained in controlled conditions and examined microscopically every 4 days. Haematocrit value and body mass were monitored in parallel. At the end of the experiment (44 days post exposure), samples of internal organs were collected and examined using histological methods for possible presence of phanerozoites. Results All control birds remained uninfected. Experimental starlings were resistant. All exposed crossbills were susceptible and survived until the end of this study. Prepatent period was 12–16 days post exposure. Light parasitaemia (< 0.7%) developed in all birds, and only few phanerozoites were seen in bone marrow cells of 5 of 8 experimentally infected crossbills. Significant changes were reported only in haematocrit value but not body mass in the exposed crossbills compared to controls. Conclusion Plasmodium elongatum (pGRW6) is of low virulence in Common crossbills and is unable to develop in Common starlings, indicating innate resistance of the later bird species. Low virulence in Common crossbills is likely due to the inability or low ability of this parasite lineage to develop phanerozoites resulting in light (if at all) damage of stem bone marrow cells. This study suggests that susceptibility of different bird species to the lineage pGRW6 is markedly variable. The global distribution of this parasite might be due to low virulence in wild adapted avian hosts, which survive this infection and serve as reservoirs host for non-adapted birds in whom this infection is often lethal.http://link.springer.com/article/10.1186/s12936-019-2926-4Avian malariaPlasmodiumPlasmodium elongatumBirdsPhanerozoitesPathology
spellingShingle Mikas Ilgūnas
Vaidas Palinauskas
Elena Platonova
Tatjana Iezhova
Gediminas Valkiūnas
The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite
Malaria Journal
Avian malaria
Plasmodium
Plasmodium elongatum
Birds
Phanerozoites
Pathology
title The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite
title_full The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite
title_fullStr The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite
title_full_unstemmed The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite
title_short The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite
title_sort experimental study on susceptibility of common european songbirds to plasmodium elongatum lineage pgrw6 a widespread avian malaria parasite
topic Avian malaria
Plasmodium
Plasmodium elongatum
Birds
Phanerozoites
Pathology
url http://link.springer.com/article/10.1186/s12936-019-2926-4
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