| 1. |
- Bensch, Staffan, et al.
(författare)
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How can we determine the molecular clock of malaria parasites?
- 2013
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Ingår i: Trends in Parasitology. - : Elsevier BV. - 1471-5007 .- 1471-4922. ; 29:8, s. 363-369
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Forskningsöversikt (refereegranskat)abstract
- The association of contemporary hosts and their parasites might reflect either cospeciation or more recent shifts among existing hosts. Cospeciation implies that lineages of hosts and parasites diverge in parallel at the same time, but testing this prediction requires time-calibrated phylogenies, which are particularly difficult to obtain in organisms that leave few fossils. It has successively become clear that host shifts have been frequent in the evolutionary history of malaria parasites, but dating these host shifts cannot be done without calibrated phylogenies. Hence, it remains unresolved how long contemporary hosts and vectors have been coevolving with their malaria parasites. This review addresses conflicting rate estimates of molecular evolution and suggests research directions to aid dating diversification events in malaria parasites.
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| 2. |
- Ferraguti, Martina, et al.
(författare)
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Environmental, geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species
- 2023
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:5, s. 809-823
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations. Location: Global. Time period: 2002–2019. Major taxa studied: Avian Plasmodium parasites in house sparrows. Methods: We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests. Results: Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected. Main conclusions: Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.
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| 3. |
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| 4. |
- Hellgren, Olof, et al.
(författare)
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Diversity and phylogeny of mitochondrial cytochrome b lineages from six morphological species of avian Haemoproteus
- 2007
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Ingår i: The Journal of Parasitology. - 0022-3395. ; 93:4, s. 889-896
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Tidskriftsartikel (refereegranskat)abstract
- Species of Haemoproteus (Haemosporida: Haemoproteidae), avian haemosporidians, have traditionally been described based on morphology of their gametocytes and on limited experimental information on their vertebrate host specificity. We investigated to what extent the morphological species are represented by monophyletic groups based on DNA sequence data using 2 different fragment lengths of the cytochrome b (cyt. b) gene. Phylogenetic reconstructions of obtained cyt. b lineages from 6 morphospecies of Haemoproteus showed that all lineages formed monophyletic clusters matching the morphospecies. Comparing our data with a recently published study showed that this is not always the case; the morphospecies H. belopolskyi consists of 2 distinct clusters of lineages that apparently have converged in morphology. However, the overall broad congruence between the molecular and morphological clustering of lineages will facilitate the integration of the knowledge obtained by traditional and molecular parasitology. Mean between morphospecies variation was 10-fold higher than the within species variation (5.5% vs. 0.54%), suggesting that Haemoproteus lineages with a genetic differentiation >5% are expected to be morphologically differentiated in most cases. When investigate the utility of 2 different fragment sizes of the cyt. b gene, the partial, 479-bp, cyt. b protocol picked up all mitochondrial (mt)DNA lineages that are found when using the full cyt. b gene, 1073 bp, suggesting that this protocol is sufficient for identification of most mtDNA lineages. All of the mtDNA lineages were associated with unique alleles when amplification was possible at a nuclear locus, strengthening the hypothesis that the designation of lineages based on mtDNA is largely genome-wide representative. We, therefore, propose the use of a cyt. b fragment of this length as a standard gene fragment for a DNA bar-coding system for avian Haemoproteus species.
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| 5. |
- Hellgren, Olof, et al.
(författare)
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Low haemosporidian diversity and one key-host species in a bird malaria community on a mid-atlantic island (sao miguel, azores)
- 2011
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Ingår i: Journal of Wildlife Diseases. - 0090-3558. ; 47:4, s. 849-859
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Tidskriftsartikel (refereegranskat)abstract
- When host species colonize new areas, the parasite assemblage infecting the hosts might change, with some parasite species being lost and others newly acquired. These changes would likely lead to novel selective forces on both host and its parasites. We investigated the avian blood parasites in the passerine bird community on the mid-Atlantic island of Sao Miguel, Azores, a bird community originating from continental Europe. The presence of haemosporidian blood parasites belonging to the genera Haemoproteus, Plasmodium, and Leucocytozoon was assessed using polymerase chain reaction. We found two Plasmodium lineages and two Leucocytozoon lineages in 11 bird species (84% of all breeding passerine species) on the island. These line ages were unevenly distributed across bird species. The Eurasian Blackbird (Turdus merula) was the key-host species (total parasite prevalence of 57%), harboring the main proportion of parasite infections. Except for Eurasian Blackbirds, all bird species had significantly lower prevalence and parasite diversity compared to their continental populations. We propose that in evolutionary novel bird communities, single species may act as key hosts by harboring the main part of the parasite fauna from which parasites "leak" into the other species. This would create very different host parasite associations in areas recently colonized by hosts as compared to in their source populations.
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| 6. |
- Krizanauskiene, Asta, et al.
(författare)
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Molecular characterization of Haemoproteus sacharovi (Haemosporida, Haemoproteidae), a common parasite of columbiform birds, with remarks on classification of haemoproteids of doves and pigeons
- 2013
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Ingår i: Zootaxa. - 1175-5334. ; 3616:1, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- Haemoproteus (Haemosporida, Haemoproteidae) is the largest genus of avian haemosporidian parasites, some species of which cause lethal diseases in birds. Subgenera Parahaemoproteus and Haemoproteus are usually accepted in this genus; these parasites are transmitted by biting midges (Ceratopogonidae) and hippoboscid flies (Hippoboscidae), respectively. As of yet, species of Parahaemoproteus have not been reported to infect doves and pigeons (Columbiformes), parasites of these birds have not been reported to be transmitted by biting midges (Ceratopogonidae). Applying microscopy and PCR based methods, we identified mitochondrial cytochrome b (cyt b) sequences of Haemoproteus sacharovi, a widespread parasite of doves and pigeons. Phylogenetic relationships of dove haemoproteids, which traditionally have been classified in the subgenus Haemoproteus, showed that H. sacharovi and H. turtur, common parasites of doves, branch in the clade with Parahaemoproteus species, indicating that these haemoproteids may belong to this subgenus and are likely transmitted by biting midges. This study provides barcodes for H. sacharovi, clarifies the taxonomic positions of H. sacharovi and H. turtur, and indicates directions for development of classification of avian haemoproteid species. Our analysis shows that the current subgeneric classification of avian haemoproteids is generally effective, but the position of some species may need to be revised.
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| 7. |
- Krizanauskiene, Asta, et al.
(författare)
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Molecular phylogenetic and morphological analysis of haemosporidian parasites (Haemosporida) in a naturally infected European songbird, the blackcap Sylvia atricapilla, with description of Haemoproteus pallidulus sp. nov
- 2010
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Ingår i: Parasitology. - 1469-8161. ; 137:2, s. 217-227
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Tidskriftsartikel (refereegranskat)abstract
- The blackcap (Sylvia atricapilla) is a common Palearctic migratory warbler, and haemosporidian parasites are common in this species. However, genetic and phenotypic diversity of haemosporidians in warblers has been insufficiently investigated and poorly linked. We addressed this issue by combining molecular and microscopy data for detection of pigment-forming haemosporidians of the genera Haemoproteus and Plasmodium. Blood samples from 498 blackcaps were collected at 7 different sites in Europe and investigated for these parasites by polymerase chain reaction (PCR)-based techniques and microscopic examination. In all, 56% of the birds were infected by at least 1 out of 25 distinct mitochondrial cytochrome b (cyt b) gene lineages of these haemosporidians. It is concluded that the blackcap is infected not only with blackcap specific haemosporidians, but also with Haemoproteus majoris, which is a host generalist and common in birds belonging to the Paridae. Haemoproteus pallidulus sp. nov. is described based on morphology of its blood stages and segments of the cyt b and dihydrofolate reductase/thymidylate synthase (DHFR-TS) genes. This study provides evidence that genetic diversity of haemosporidian parasites might be positively correlated with migratory strategies of their avian hosts; it also contributes to the value of both microscopy and molecular diagnostics of avian blood parasites.
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| 8. |
- Marzal, Alfonso, et al.
(författare)
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Diversity, Loss, and Gain of Malaria Parasites in a Globally Invasive Bird.
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing with them novel pathogens to which native species are not adapted. In contrast, the Enemy Release Hypothesis suggests that flourishing colonizers are successful because they have left their pathogens behind. To assess the role of avian malaria and related haemosporidian parasites in the global spread of a common invasive bird, we examined the prevalence and genetic diversity of haemosporidian parasites (order Haemosporida, genera Plasmodium and Haemoproteus) infecting house sparrows (Passer domesticus). We sampled house sparrows (N = 1820) from 58 locations on 6 continents. All the samples were tested using PCR-based methods; blood films from the PCR-positive birds were examined microscopically to identify parasite species. The results show that haemosporidian parasites in the house sparrows' native range are replaced by species from local host-generalist parasite fauna in the alien environments of North and South America. Furthermore, sparrows in colonized regions displayed a lower diversity and prevalence of parasite infections. Because the house sparrow lost its native parasites when colonizing the American continents, the release from these natural enemies may have facilitated its invasion in the last two centuries. Our findings therefore reject the Novel Weapon Hypothesis and are concordant with the Enemy Release Hypothesis.
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| 9. |
- Palinauskas, Vaidas, et al.
(författare)
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A new method for isolation of purified genomic DNA from haemosporidian parasites inhabiting nucleated red blood cells
- 2013
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Ingår i: Experimental Parasitology. - : Elsevier BV. - 0014-4894. ; 133:3, s. 275-280
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Tidskriftsartikel (refereegranskat)abstract
- During the last 10 years, whole genomes have been sequenced from an increasing number of organisms. However, there is still no data on complete genomes of avian and lizard Plasmodium spp. or other haemosporidian parasites. In contrast to mammals, bird and reptile red blood cells have nuclei and thus blood of these vertebrates contains high amount of host DNA; that complicates preparation of purified template DNA from haemosporidian parasites, which has been the main obstacle for genomic studies of these parasites. In the present study we describe a method that generates large amount of purified avian haemosporidian DNA. The method is based on a unique biological feature of haemosporidian parasites, namely that mature gametocytes in blood can be induced to exflagellate in vitro. This results in the development of numerous microgametes, which can be separated from host blood cells by simple centrifugation. Our results reveal that this straight forward method provides opportunities to collect pure parasite DNA material, which can be used as a template for various genetic analyses including whole genome sequencing of haemosporidians infecting birds and lizards. (c) 2012 Elsevier Inc. All rights reserved.
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| 10. |
- Palinauskas, Vaidas, et al.
(författare)
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Molecular characterization and distribution of Haemoproteus minutus (Haemosporida, Haemoproteidae): A pathogenic avian parasite
- 2013
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Ingår i: Parasitology International. - : Elsevier BV. - 1383-5769. ; 62:4, s. 358-363
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the lineage hTURDUS2 of Haemoproteus minutus (Haemosporida, Haemoproteidae) was reported to cause mortality in captive parrots. This parasite lineage is widespread and prevalent in the blackbird Turdus merula throughout its entire distribution range. Species identity of other closely related lineages recently reported in dead parrots remains unclear, but will be important to determine for a better understanding of the epidemiology of haemoproteosis. Using polymerase chain reaction (PCR)-based and microscopic methods, we analyzed 265 blood samples collected from 52 species of wild birds in Eurasia (23 samples from Kamchatka Peninsula, 73 from Sakhalin Island, 150 from Ekaterinburg and 19 from Irkutsk regions of Russia). Single infections of the lineages hTURDUS2 (hosts are redwing Turdus iliacus and fieldfare Turdus pilaris), hTUPHI1 (song thrush Turdus philomelos) and hTUCHR01 (fieldfare, redwing, song thrush and brown-headed thrush Turdus chysolaus) were detected. We identified species of these haemoproteids based on morphology of their blood stages and conclude that these lineages belong to H. minutus, a widespread parasite of different species of thrushes (genus Turdus), which serve as reservoir hosts of this haemoproteid infection. Phylogenetic analysis shows that the lineages hTURDUS2, hTUCHR01 and hTUPHI1 of H. minutus are closely related to Haemoproteus pallidus (lineages hPFC1 and hCOLL2), Haemoproteus pallidulus (hSYAT03), and Haemoproteus sp. (hMEUND3); genetic distance among their mitochondrial cytochrome b (cyt b) lineages is small (<1% or <4 nucleotides). All these blood parasites are different in many morphological characters, but are similar due to one feature, which is the pale staining of their macrogametocytes' cytoplasm with Giemsa. Because of the recent publications about mortality caused by the lineages hTUPHI1 and hTURDUS2 of H. minutus in captive parrots in Europe, H. minutus and the closely related H. pallidus and H. pallidulus are worth more attention as these are possible agents of haemoproteosis in exotic birds. The present study provides barcodes for molecular detection of different lineages of H. minutus, and extends information about the distribution of this blood parasite. (C) 2013 Elsevier Ireland Ltd. All rights reserved.
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| 11. |
- Palinauskas, Vaidas, et al.
(författare)
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Plasmodium relictum (lineage P-SGS1): Further observation of effects on experimentally infected passeriform birds, with remarks on treatment with Malarone (TM)
- 2009
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Ingår i: Experimental Parasitology. - : Elsevier BV. - 0014-4894. ; 123:2, s. 134-139
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Tidskriftsartikel (refereegranskat)abstract
- Plasmodium relictum (lineage P-SGS1) is a widespread malaria parasite that causes disease of different severity in different species of birds. However, experimental studies on the effects of this parasite on avian hosts are uncommon. We investigated development of this lineage in experimentally infected greenfinches Carduelis chloris and compared the obtained data with the literature information about the virulence of the same parasite lineage for phylogenetically closely related bird species. We also used an opportunity to test the efficacy of the antimalarial drug Malarone (TM) in treatment of the experimental infection. The cryopreserved strain of the lineage P-SGS1 was multiplied in 4 experimentally infected chaffinches. Light parasitemia developed in these birds; the parasites were then inoculated to 6 uninfected recipient greenfinches. Six uninfected greenfinches were used as negative controls. Light parasitemia developed in all experimental greenfinches. There were no significant effects of malaria on the body mass of greenfinches, but haematocrit value was slightly lower in experimental birds than in control ones; the infection did not cause mortality or morbidity in these birds. According to available data, all investigated fringillid birds are susceptible to P. relictum (P-SGS1), but the same malaria parasite develops markedly differently in different bird species, even closely related hosts. Thus, the observed effects of the same malaria lineage on one species of bird cannot be generalized to others, even closely related ones. The cure with Malarone (TM) was highly efficient for blood stages of P. relictum, but exoerythrocytic stages were unaffected. (C) 2009 Elsevier Inc. All rights reserved.
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| 12. |
- Perez-Tris, Javier, et al.
(författare)
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What are malaria parasites?
- 2005
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Ingår i: Trends in Parasitology. - : Elsevier BV. ; 21:5, s. 209-211
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Tidskriftsartikel (refereegranskat)
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| 13. |
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| 14. |
- Perez-Tris, Javier, et al.
(författare)
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Within-host speciation of malaria parasites
- 2007
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 2:2
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Tidskriftsartikel (refereegranskat)abstract
- Background Sympatric speciation—the divergence of populations into new species in absence of geographic barriers to hybridization—is the most debated mode of diversification of life forms. Parasitic organisms are prominent models for sympatric speciation, because they may colonise new hosts within the same geographic area and diverge through host specialization. However, it has been argued that this mode of parasite divergence is not strict sympatric speciation, because host shifts likely cause the sudden effective isolation of parasites, particularly if these are transmitted by vectors and therefore cannot select their hosts. Strict sympatric speciation would involve parasite lineages diverging within a single host species, without any population subdivision. Methodology/Principal Findings Here we report a case of extraordinary divergence of sympatric, ecologically distinct, and reproductively isolated malaria parasites within a single avian host species, which apparently occurred without historical or extant subdivision of parasite or host populations. Conclusions/Significance This discovery of within-host speciation changes our current view on the diversification potential of malaria parasites, because neither geographic isolation of host populations nor colonization of new host species are any longer necessary conditions to the formation of new parasite species.
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| 15. |
- Valkiunas, Gediminas, et al.
(författare)
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Polymerase chain reaction-based identification of Plasmodium (Huffia) elongatum, with remarks on species identity of haemosporidian lineages deposited in GenBank
- 2008
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Ingår i: Parasitology Reseach. - : Springer Science and Business Media LLC. - 1432-1955 .- 0932-0113. ; 102:6, s. 1185-1193
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Tidskriftsartikel (refereegranskat)abstract
- Numerous lineages of avian malaria parasites of the genus Plasmodium have been deposited in GenBank. However, only 11 morphospecies of Plasmodium have been linked to these lineages. Such linking is important because it provides opportunities to combine the existing knowledge of traditional parasitology with novel genetic information of these parasites obtained by molecular techniques. This study linked one mitochondrial cytochrome b (cyt b) gene lineage with morphospecies Plasmodium (Huffia) elongatum, a cosmopolitan avian malaria parasite which causes lethal disease in some birds. One species of Plasmodium (mitochondrial cyt b gene lineage P-GRW6) was isolated from naturally infected adult great reed warblers (Acrocephalus arundinaceus) and inoculated to one naive juvenile individual of the same host species. Heavy parasitaemia developed in the subinoculated bird, which enabled identification of the morphospecies and deposition of its voucher specimens. The parasite of this lineage belongs to P. elongatum. Illustrations of blood stages of this parasite are given. Other lineages closely related to P. elongatum were identified. The validity of the subgenus Huffia is supported by phylogenetic analysis. Mitochondrial cyt b gene lineages, with GenBank accession nos. AF069611 and AY733088, belong to Plasmodium cathemerium and P. elongatum, respectively; these lineages have been formerly attributed to P. elongatum and P. relictum, respectively. Some other incorrect species identifications of avian haematozoa in GenBank have been identified. We propose a strategy to minimise the number of such mistakes in GenBank in the future.
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| 16. |
- Zehtindjiev, Pavel, et al.
(författare)
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Haemosporidian infections in skylarks (Alauda arvensis): a comparative PCR-based and microscopy study on the parasite diversity and prevalence in southern Italy and the Netherlands
- 2012
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Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 58:1, s. 335-344
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Tidskriftsartikel (refereegranskat)abstract
- Changes in agricultural management have been identified as the most probable cause for the decline of Skylark (Alauda arvensis) populations in Europe. However, parasitic infections have not been considered as a possible factor influencing this process. Four hundred and thirty-four Skylarks from the Southern Italy and the Netherlands were screened for haemosporidian parasites (Haemosporida) using the microscopy and polymerase chain reaction (PCR)-based methods. The overall prevalence of infection was 19.5%; it was 41.8% in Italian birds and 8.3% in Dutch birds. The prevalence of Plasmodium spp. was 34.1% and 6.5% in Skylarks from Italy and Netherlands, respectively. Approximately 15% of all recorded haemosporidian infections were simultaneous infections both in Italian and Dutch populations. Six different mitochondrial cytochrome b (cyt b) lineages of Plasmodium spp. and three lineages of Haemoproteus tartakovskyi were found. The lineage SGS1 of Plasmodium relictum was the most prevalent at both study sites; it was recorded in 24.7% of birds in Italy and 5.5% in the Netherlands. The lineages SYAT05 of Plasmodium vaughani and GRW11 of P. relictum were also identified with a prevalence of <2% at both study sites. Two Plasmodium spp. lineages (SW2 and DELURB4) and three H. tartakovskyi lineages have been found only in Skylarks from Italy. Mitochondrial cyt b lineages SYAT05 are suggested for molecular identification of P. vaughani, a cosmopolitan malaria parasite of birds. This study reports the greatest overall prevalence of malaria infection in Skylarks during the last 100 years and shows that both Plasmodium and Haemoproteus spp. haemosporidian infections are expanding in Skylarks so it might contribute to a decrease of these bird populations in Europe.
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| 17. |
- Zehtindjiev, Pavel, et al.
(författare)
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Occurrence of haemosporidian parasites in the paddyfield warbler, Acrocephalus agricola (Passeriformes, Sylviidae)
- 2009
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Ingår i: Acta Parasitologica. - : Walter de Gruyter GmbH. - 1230-2821 .- 1896-1851. ; 54:4, s. 295-300
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Tidskriftsartikel (refereegranskat)abstract
- The blood parasite diversity was studied in paddyfield warblers (Acrocephalus agricola) breeding in NE Bulgaria, SW Russia and S. Kazakhstan. Nine cytochrome b gene lineages were recorded, 4 belonging to Haemoproteus spp. and 5 to Plasmodium spp. The overall prevalence of haemosporidians was 33.3%. The composition of parasites varied geographically, with six lineages recorded in Russia, five lineages in Bulgaria and two lineages in Kazakhstan. Two lineages are described for the first time, i.e. ACAGR1 (belonging to Plasmodium sp. and recorded from a single bird in Russia) and ACAGR2 (belonging to Haemoproteus sp., recorded from Bulgaria and Russia). The latter lineage is the most widespread parasite in the Bulgarian population, scarce in Russia and absent in Kazakhstan. It is supposed that ACAGR2 has originated from the widespread lineage ACDUM1 differing from it by a single nucleotide. One lineage only (ACDUM2) occurs in all the three populations studied and is a nonspecific parasite known from various passerines. Six of the registered lineages have been found in a single population of A. agricola and also represent non-specific parasites occurring in a wide range of passerine birds. Their records in A. agricola may indicate the high transmission rate of these parasites in the habitats where this host co-occurs with other passerines. The variation of the composition of the haemosporidian parasite communities through the breeding range of A. agricola makes up heterogeneous selection pressures that may drive intraspecific variation in important life-history traits.
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