BACKGROUND: Platyhelminthes are common parasites of diurnal birds of prey, including common buzzard (Buteo buteo). They are widely distributed in Europe. Despite the extensive study of flatworms across the continent, this study represents the first report for Romania and extends the biogeographic knowledge of Platyhelminthes in diurnal raptors. It also identifies common buzzards as a new host of Parastrigea flexilis in Europe. MATERIALS AND METHODS: Between 2017 and 2020, 63 common buzzards (Buteo buteo) found road killed or dead due to other causes were collected from Romania. All specimens were necropsied and examined for internal helminths, which were preserved in ethanol for molecular identification and formaldehyde for morphological identification. RESULTS: Species identified included Cestoda: Cladotaenia globifera (33.3%) and five species of Trematoda: Neodiplostomum attenuatum (12.7%), Strigea falconis (6.4%), Parastrigea flexilis (3.2%), Neodiplostomum spathoides (3.2%) and Brachylaima fuscata (1.6%). CONCLUSIONS: This study provides new data about diversity, phylogenetics and geographical distribution of Platyhelminthes parasitizing Buteo buteo in Romania. To our best knowledge, it identifies B. buteo as a new host of Parastrigea flexilis and reports the first genetic sequence of Neodiplostomum spathoides.
- Publication type
- Journal Article MeSH
The prevalences of heteroxenous parasites are influenced by the interplay of three main actors: hosts, vectors, and the parasites themselves. We studied blood protists in the nesting populations of raptors in two different areas of the Czech Republic. Altogether, 788 nestlings and 258 adult Eurasian sparrowhawks (Accipiter nisus) and 321 nestlings and 86 adult common buzzards (Buteo buteo) were screened for parasites by the microscopic examination of blood smears and by cultivation. We examined the role of shared vectors and parasite phylogenetic relationships on the occurrence of parasites. In different years and hosts, trypanosome prevalence ranged between 1.9 and 87.2 %, that of Leucocytozoon between 1.9 and 100 %, and Haemoproteus between 0 and 72.7 %. Coinfections with Leucocytozoon and Trypanosoma, phylogenetically distant parasites but both transmitted by blackflies (Simuliidae), were more frequent than coinfections with Leucocytozoon and Haemoproteus, phylogenetically closely related parasites transmitted by different vectors (blackflies and biting midges (Ceratopogonidae), respectively). For example, 16.6 % buzzard nestlings were coinfected with Trypanosoma and Leucocytozoon, while only 4.8 % with Leucocytozoon and Haemoproteus and 0.3 % with Trypanosoma and Haemoproteus. Nestlings in the same nest tended to have the same infection status. Furthermore, prevalence increased with the age of nestlings and with Julian date, while brood size had only a weak negative/positive effect on prevalence at the individual/brood level. Prevalences in a particular avian host species also varied between study sites and years. All these factors should thus be considered while comparing prevalences from different studies, the impact of vectors being the most important. We conclude that phylogenetically unrelated parasites that share the same vectors tend to have similar distributions within the host populations of two different raptor species.
- MeSH
- Raptors parasitology MeSH
- Falconiformes parasitology MeSH
- Phylogeny MeSH
- Haemosporida classification genetics isolation & purification physiology MeSH
- Insect Vectors parasitology physiology MeSH
- Host Specificity MeSH
- Bird Diseases epidemiology parasitology transmission MeSH
- Prevalence MeSH
- Protozoan Infections, Animal epidemiology parasitology transmission MeSH
- Birds parasitology MeSH
- Simuliidae parasitology physiology MeSH
- Trypanosoma classification genetics isolation & purification physiology MeSH
- Animals MeSH
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- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
BACKGROUND: There is growing interest in the issue of disease reactivation in multiple sclerosis following fingolimod cessation. Relatively little is known about modifiers of the risk of post-cessation relapse, including the delay to commencement of new therapy and prior disease activity. OBJECTIVE: We aimed to determine the rate of relapse following cessation of fingolimod and to identify predictors of relapse following cessation. METHODS: Data were extracted from the MSBase registry in March 2019. Inclusion criteria were (a) clinically definite relapsing multiple sclerosis, (b) treatment with fingolimod for ≥ 12 months, (c) follow-up after cessation for ≥ 12 months, and (d) at least one Expanded Disability Status Scale score recorded in the 12 months before cessation. RESULTS: A total of 685 patients were identified who met criteria. The mean annualised relapse rate was 1.71 (95% CI 1.59, 1.85) in the year prior to fingolimod, 0.50 (95% CI 0.44, 0.55) on fingolimod and 0.43 (95% CI 0.38, 0.49) after fingolimod. Of these, 218 (32%) patients experienced a relapse in the first 12 months. Predictors of a higher relapse rate in the first year were: younger age at fingolimod cessation, higher relapse rate in the year prior to cessation, delaying commencement of new therapy and switching to low-efficacy therapy. CONCLUSIONS: Disease reactivation following fingolimod cessation is more common in younger patients, those with greater disease activity prior to cessation and in those who switch to a low-efficacy therapy.
In the vertebrate retina, amacrine and ganglion cells represent the most diverse cell classes. They can be classified into different cell types by several features, such as morphology, light responses, and gene expression profile. Although birds possess high visual acuity (similar to primates that we used here for comparison) and tetrachromatic color vision, data on the expression of transcription factors in retinal ganglion cells of birds are largely missing. In this study, we tested various transcription factors, known to label subpopulations of cells in mammalian retinae, in two avian species: the common buzzard (Buteo buteo), a raptor with exceptional acuity, and the domestic pigeon (Columba livia domestica), a good navigator and widely used model for visual cognition. Staining for the transcription factors Foxp2, Satb1 and Satb2 labeled most ganglion cells in the avian ganglion cell layer. CtBP2 was established as marker for displaced amacrine cells, which allowed us to reliably distinguish ganglion cells from displaced amacrine cells and assess their densities in buzzard and pigeon. When we additionally compared the temporal and central fovea of the buzzard with the fovea of primates, we found that the cellular organization in the pits was different in primates and raptors. In summary, we demonstrate that the expression of transcription factors is a defining feature of cell types not only in the retina of mammals but also in the retina of birds. The markers, which we have established, may provide useful tools for more detailed studies on the retinal circuitry of these highly visual animals.
- MeSH
- Amacrine Cells chemistry metabolism MeSH
- Callithrix MeSH
- Columbidae MeSH
- Species Specificity MeSH
- Retina chemistry cytology metabolism MeSH
- Transcription Factors analysis biosynthesis genetics MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
Visual (and probably also magnetic) signal processing starts at the first synapse, at which photoreceptors contact different types of bipolar cells, thereby feeding information into different processing channels. In the chicken retina, 15 and 22 different bipolar cell types have been identified based on serial electron microscopy and single-cell transcriptomics, respectively. However, immunohistochemical markers for avian bipolar cells were only anecdotally described so far. Here, we systematically tested 12 antibodies for their ability to label individual bipolar cells in the bird retina and compared the eight most suitable antibodies across distantly related species, namely domestic chicken, domestic pigeon, common buzzard, and European robin, and across retinal regions. While two markers (GNB3 and EGFR) labeled specifically ON bipolar cells, most markers labeled in addition to bipolar cells also other cell types in the avian retina. Staining pattern of four markers (CD15, PKCα, PKCβ, secretagogin) was species-specific. Two markers (calbindin and secretagogin) showed a different expression pattern in central and peripheral retina. For the chicken and European robin, we found slightly more ON bipolar cell somata in the inner nuclear layer than OFF bipolar cell somata. In contrast, OFF bipolar cells made more ribbon synapses than ON bipolar cells in the inner plexiform layer of these species. Finally, we also analyzed the photoreceptor connectivity of selected bipolar cell types in the European robin retina. In summary, we provide a catalog of bipolar cell markers for different bird species, which will greatly facilitate analyzing the retinal circuitry of birds on a larger scale.
- MeSH
- Retinal Bipolar Cells MeSH
- Retinal Cone Photoreceptor Cells MeSH
- Microscopy, Electron MeSH
- Chickens MeSH
- Retina chemistry MeSH
- Secretagogins * metabolism MeSH
- Synapses metabolism MeSH
- Songbirds * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
