| 1. |
- Ferraguti, Martina, et al.
(author)
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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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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:5, s. 809-823
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Journal article (peer-reviewed)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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| 2. |
- Bobeva, Aneliya, et al.
(author)
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A survey of biting midges of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) in NE Bulgaria, with respect to transmission of avian haemosporidians
- 2013
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In: Acta Parasitologica. - : Walter de Gruyter GmbH. - 1230-2821 .- 1896-1851. ; 58:4, s. 585-591
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Journal article (peer-reviewed)abstract
- This study presents data from a molecular survey of the species of the genus Culicoides from the region of Kalimok Field Station (NE Bulgaria) and haemosporidian parasites occurring in them in order to investigate the host-parasite specificity of haemosporidians to their dipteran vectors. The identification of Culicoides spp. was carried out by morphological and molecular-genetic methods. We collected and analysed 230 individuals of the genus Culicoides. Nine species were found. Eight species were identified morphologically; Culicoides obsoletus, C. riethi, C. newsteadi, C. circumscriptus, C. festivipennis, C. punctatus, C. pictipennis and C. puncticollis. The ninth species might be classified as either of C. nubeculosus or C. riethi and its identification needs additional investigations. The total prevalence of Haemoproteus in the examined biting midges was 2.17%. Three individuals of C. pictipennis were infected with the Haemoproteus lineage TURDUS2 (prevalence 16.67%), a common parasite of thrushes (Turdidae). Two individuals of C. circumscriptus contained Haemoproteus lineages (prevalence 2.78%); these were the lineage HAWF2 (previously reported from Coccothraustes coccothraustes) and a new lineage CULCIR1 not previously reported in the literature.
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| 3. |
- Bobeva, Aneliya, et al.
(author)
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Degree of associations among vectors of the genus Culicoides (Diptera: Ceratopogonidae) and host bird species with respect to haemosporidian parasites in NE Bulgaria
- 2014
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In: Parasitology Reseach. - : Springer Science and Business Media LLC. - 1432-1955 .- 0932-0113. ; 113:12, s. 4505-4511
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Journal article (peer-reviewed)abstract
- The occurrence of haemosporidians in biting midges of the genus Culicoides is examined in North-East Bulgaria in order to reveal their potential role for parasite transmission. A PCR-based technique amplifying part of the mitochondrial cytochrome b gene of the parasite is applied on naturally infected biting midges. Totally, 640 parous individuals of four species and 95 blood-fed individuals of six species of Culicoides are examined for the presence of DNA of haemosporidians. Haemosporidian genetic lineages are identified in individuals of three insect species: Culicoides alazanicus (12 lineages, nine lineages of Haemoproteus and three lineages of Plasmodium), Culicoides festivipennis and Culicoides circumscriptus (with two and one lineages of Haemoproteus, respectively). Two genetic lineages of Haemoproteus are recorded in more than one vector species. These results demonstrate variations in the specificity of Haemoproteus genetic lineages to their potential vectors, since some lineages are recorded in a single vector species and others occur in two or more vector species.
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| 4. |
- Dimitrov, Dimitar, et al.
(author)
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Genetic diversity of avian blood parasites in SE Europe: Cytochrome b lineages of the genera Plasmodium and Haemoproteus (Haemosporida) from Bulgaria
- 2010
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In: Acta Parasitologica. - : Walter de Gruyter GmbH. - 1230-2821 .- 1896-1851. ; 55:3, s. 201-209
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Journal article (peer-reviewed)abstract
- We used a nested PCR protocol to examine the genetic diversity of cytochrome b (cyt b) lineages from blood parasites of the genera Plasmodium and Haemoproteus in birds in Bulgaria. In total, 460 birds of 43 species and 14 families (mostly passerines) were examined for the presence of infections. Of them, 267 were recognised as infected with haemosporidian parasites. Mixed infections were recorded in 24 individuals (9%). Besides the 24 individuals with mix infections, 114 (43%) were positive for Plasmodium spp. and 129 (48%) for Haemoproteus spp. We identified 52 genetic lineages of haemosporidian parasites: 38 of Haemoproteus and 14 of Plasmodium. Twelve new cyt b lineages of Haemoproteus were recorded; they occurred in the following hosts: grey-faced woodpecker (Picus canus), golden oriole (Oriolus oriolus), jay (Garrulus glandarius), barred warbler (Sylvia nisoria), song thrush (Turdus philomelos), spotted flycatcher (Muscicapa striata), spanish sparrow (Passer hispaniolensis), hawfinch (Coccothraustes coccothraustes), and cirl bunting (Emberiza cirlus). We also detected 22 new host records for previously known lineages. The most common lineage was SGS1 (Plasmodium relictum), which had a total prevalence of 14% and occurred in 8 host species belonging to 5 families. Three of the cyt b lineages of genus Haemoproteus (DURB1, DURB2 and SYNIS2) showed more than 5% divergence from all described morphologically lineages. These lineages probably represent at least 2 different morphospecies which remains to be identified.
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| 5. |
- Dimitrov, Dimitar, et al.
(author)
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Molecular characterization of haemosporidian parasites (Haemosporida) in yellow wagtail (Motacilla flava), with description of in vitro ookinetes of Haemoproteus motacillae
- 2013
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In: Zootaxa. - : Magnolia Press. - 1175-5334 .- 1175-5326. ; 3666:3, s. 369-381
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Journal article (peer-reviewed)abstract
- In studies of haemosporidian systematics and taxonomy, a combination of microscopic examination and molecular identification has been recommended. The yellow wagtail (Motacilla flava) is a frequently used species in studies of host-parasite interactions; blood parasites of this bird have been well studied using microscopic examination of blood films, but data on molecular characterization of the parasites are scattered. Here we present the first study linking several haemosporidian cyt b sequences with their morphospecies parasitizing the yellow wagtail, combining light microscopy and nested PCR methods. The lineage hYWT1 of Haemoproteus motacillae was the most prevalent parasite; it was recorded in 38% of the birds. The latter lineage and the lineages hYWT2, hYWT3, hYWT5 and hYWT6 form a well-supported clade on the phylogenetic tree and likely represent intraspecific genetic variation of H. motacillae, with genetic divergence of 0.3-1.5 % among these lineages. Microscopic examination of smears prepared during an in vitro experiment, which was designed for observation of developing ookinetes, showed that H. motacillae ookinetes were present 5 hours after exposure of blood to air at 18-20 degrees C. Ookinetes of this parasite belong to a group of large Haemoproteus spp. ookinetes (19.9 mu m in length on average). Illustrations of the parasites are given. Two of reported Plasmodium lineages, pCOLL1 and pYWT4 are phylogenetically closely related to the widespread host generalist parasites Plasmodium relictum (cyt b lineages pSGS1, pGRW4 and pGRW11), but it was not possible to establish this morphologically. This study contributes to the molecular identification of avian haemosporidian parasites and provides information on morphology of H. motacillae ookinetes, which is additional information assisting the microscopic identification of this species.
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| 6. |
- Dimitrov, Dimitar, et al.
(author)
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Plasmodium spp.: An experimental study on vertebrate host susceptibility to avian malaria.
- 2015
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In: Experimental Parasitology. - : Elsevier BV. - 0014-4894. ; 148, s. 1-16
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Journal article (peer-reviewed)abstract
- The interest in experimental studies on avian malaria caused by Plasmodium species has increased recently due to the need of direct information about host-parasite interactions. Numerous important issues (host susceptibility, development of infection, the resistance and tolerance to avian malaria) can be answered using experimental infections. However, specificity of genetically different lineages of malaria parasites and their isolates is largely unknown. This study reviews recent experimental studies and offers additional data about susceptibility of birds to several widespread cytochrome b (cyt b) lineages of Plasmodium species belonging to four subgenera. We exposed two domesticated avian hosts (canaries Serinus canaria and ducklings Anas platyrhynchos) and also 16 species of common wild European birds to malaria infections by intramuscular injection of infected blood and then tested them by microscopic examination and PCR-based methods. Our study confirms former field and experimental observations about low specificity and wide host-range of Plasmodium relictum (lineages SGS1 and GRW11) and P. circumflexum (lineage TURDUS1) belonging to the subgenera Haemamoeba and Giovannolaia, respectively. However, the specificity of different lineages and isolates of the same parasite lineage differed between species of exposed hosts. Several tested Novyella lineages were species specific, with a few cases of successful development in experimentally exposed birds. The majority of reported cases of mortality and high parasitaemia were observed during parasite co-infections. Canaries were susceptible mainly for the species of Haemamoeba and Giovannolaia, but were refractory to the majority of Novyella isolates. Ducklings were susceptible to three malaria infections (SGS1, TURDUS1 and COLL4), but parasitaemia was light (<0.01%) and transient in all exposed birds. This study provides novel information about susceptibility of avian hosts to a wide array of malaria parasite lineages, outlining directions for future experimental research on various aspects of biology and epidemiology of avian malaria.
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| 7. |
- Emmenegger, Tamara, et al.
(author)
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Effects of blood parasite infections on spatiotemporal migration patterns and activity budgets in a long-distance migratory passerine
- 2021
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In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:2, s. 753-762
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Journal article (peer-reviewed)abstract
- How blood parasite infections influence the migration of hosts remains a lively debated issue as past studies found negative, positive, or no response to infections. This particularly applies to small birds, for which monitoring of detailed migration behavior over a whole annual cycle has been technically unachievable so far. Here, we investigate how bird migration is influenced by parasite infections. To this end, we tracked great reed warblers (Acrocephalus arundinaceus) with multisensor loggers, characterized general migration patterns as well as detailed flight bout durations, resting times and flight heights, and related these to the genus and intensity of their avian haemosporidian infections. We found migration distances to be shorter and the onset of autumn migration to be delayed with increasing intensity of blood parasite infection, in particular for birds with Plasmodium and mixed-genus infections. Additionally, the durations of migratory flight bout were prolonged for infected compared to uninfected birds. But since severely infected birds and particularly birds with mixed-genus infections had shorter resting times, initial delays seemed to be compensated for and the timing in other periods of the annual cycle was not compromised by infection. Overall, our multisensor logger approach revealed that avian blood parasites have mostly subtle effects on migratory performance and that effects can occur in specific periods of the year only.
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| 8. |
- Hansson, Bengt, et al.
(author)
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Postglacial colonisation patterns and the role of isolation and expansion in driving diversification in a passerine bird.
- 2008
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:7
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Journal article (peer-reviewed)abstract
- Pleistocene glacial cycles play a major role in diversification and speciation, although the relative importance of isolation and expansion in driving diversification remains debated. We analysed mitochondrial DNA sequence data from 15 great reed warbler (Acrocephalus arundinaceus) populations distributed over the vast Eurasian breeding range of the species, and revealed unexpected postglacial expansion patterns from two glacial refugia. There were 58 different haplotypes forming two major clades, A and B. Clade A dominated in Western Europe with declining frequencies towards Eastern Europe and the Middle East, but showed a surprising increase in frequency in Western and Central Asia. Clade B dominated in the Middle East, with declining frequencies towards north in Central and Eastern Europe and was absent from Western Europe and Central Asia. A parsimonious explanation for these patterns is independent postglacial expansions from two isolated refugia, and mismatch distribution analyses confirmed this suggestion. Gene flow analyses showed that clade A colonised both Europe and Asia from a refugium in Europe, and that clade B expanded much later and colonised parts of Europe from a refugium in the Middle East. Great reed warblers in the eastern parts of the range have slightly paler plumage than western birds (sometimes treated as separate subspecies; A. a. zarudnyi and A. a. arundinaceus, respectively) and our results suggest that the plumage diversification took place during the easterly expansion of clade A. This supports the postglacial expansion hypothesis proposing that postglacial expansions drive diversification in comparatively short time periods. However, there is no indication of any (strong) reproductive isolation between clades and our data show that the refugia populations became separated during the last glaciation. This is in line with the Pleistocene speciation hypothesis invoking that much longer periods of time in isolation are needed for speciation to occur.
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| 9. |
- Koleček, Jaroslav, et al.
(author)
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Cross-continental migratory connectivity and spatiotemporal migratory patterns in the great reed warbler
- 2016
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In: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47:6, s. 756-767
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Journal article (peer-reviewed)abstract
- Migratory connectivity describes to which degree different breeding populations have distinct (non-overlapping) non-breeding sites. Uncovering the level of migratory connectivity is crucial for effective conservation actions and for understanding of the evolution of local adaptations and migratory routes. Here we investigate migration patterns in a passerine bird, the great reed warbler Acrocephalus arundinaceus, over its wide Western Palearctic breeding range using geolocators from Spain, Sweden, Czech Republic, Bulgaria and Turkey. We found moderate migratory connectivity: a highly significant spatial structure in the connections between breeding and sub-Saharan non-breeding grounds, but at the same time a partial overlap between individual populations, particularly along the Gulf of Guinea where the majority of birds from the Spanish, Swedish and Czech populations spent their non-breeding period. The post-breeding migration routes were similar in direction and rather parallel for the five populations. Birds from Turkey showed the most distinctive migratory routes and sub-Saharan non-breeding range, with a post-breeding migration to east Africa and, together with birds from Bulgaria, a previously unknown pre-breeding migration over the Arabian Peninsula indicating counter-clockwise loop migration. The distances between breeding and sub-Saharan non-breeding sites, as well as between first and final sub-Saharan non-breeding sites, differed among populations. However, the total speed of migration did not differ significantly between populations; neither during post-breeding migration in autumn, nor pre-breeding migration in spring. There was also no significant relationship between the total speed of migration and distance between breeding and non-breeding sites (neither post- nor pre-breeding) and, surprisingly, the total speed of migration generally did not differ significantly between post-breeding and pre-breeding migration. Future challenges include understanding whether non-breeding environmental conditions may have influenced the differences in migratory patterns that we observed between populations, and to which extent non-breeding habitat fluctuations and loss may affect population sizes of migrants.
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| 10. |
- Muhammad, Asghar, et al.
(author)
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Primary peak and chronic malaria infection levels are correlated in experimentally infected great reed warblers.
- 2012
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In: Parasitology. - 1469-8161. ; 139:10, s. 1246-1252
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Journal article (peer-reviewed)abstract
- SUMMARY Malaria parasites often manage to maintain an infection for several months or years in their vertebrate hosts. In humans, rodents and birds, most of the fitness costs associated with malaria infections are in the short initial primary (high parasitaemia) phase of the infection, whereas the chronic phase (low parasitaemia) is more benign to the host. In wild birds, malaria parasites have mainly been studied during the chronic phase of the infection. This is because the initial primary phase of infection is short in duration and infected birds with severe disease symptoms tend to hide in sheltered places and are thus rarely caught and sampled. We therefore wanted to investigate the relationship between the parasitaemia during the primary and chronic phases of the infection using an experimental infection approach. We found a significant positive correlation between parasitaemia in the primary peak and the subsequent chronic phase of infection when we experimentally infected great reed warblers (Acrocephalus arundinaceus) with Plasmodium ashfordi. The reason for this association remains to be understood, but might arise from individual variation in exoerythrocytic parasite reservoirs in hosts, parasite antigenic diversity and/or host genetics. Our results suggest that the chronic phase parasitaemia can be used to qualitatively infer the parasitaemia of the preceding and more severe primary phase, which is a very important finding for studies of avian malaria in wild populations.
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