Role of three bird species in the life cycle of two Sarcocystis species (Apicomplexa, Sarcocystidae) in the Czech Republic

BackgroundBirds are one of the groups involved in the development of Sarcocystis Lankester, 1882, serving either as intermediate or definitive hosts. The white-tailed sea eagle Haliaeetus albicilla (Linnaeus, 1758), red kite Milvus milvus (Linnaeus, 1758) (both Accipitriformes) and common starlings Sturnus vulgaris Linnaeus, 1758 (Passeriformes) were examined to elucidate their participation in the development of Sarcocystis, as well as to determine the specific identity of the parasites based on morphological and especially molecular analyses.MethodsIn 2020–2021, one white-tailed eagle, one red kite and five common starlings were parasitologically examined for the presence of Sarcocystis using flotation centrifugation coprological method and by wet mounts of intestinal mucosa scrapings and/or muscle samples. Positive samples were processed by light microscopy, histologically and followed molecularly at four genetic markers (18S rRNA, 28S rRNA, ITS1 and cox1).ResultsThe white-tailed eagle harboured oocysts/sporocysts of S. arctica Gjerde et Schulze, 2014 in the intestinal mucosa, while the intestinal mucosa of the red kite and breasts and leg muscles of one common starling were positive to S. halieti Gjerde, Vikøren et Hamnes, 2018. Sequences from eagle shared 99.6 − 100% identity with each other and S. arctica in the red fox (V. vulpes Linnaeus, 1758) from the Czech Republic. Sequences from the common starling and red kite shared 100% identity with each other and with S. halieti in the great cormorant (P. carbo [Linnaeus, 1758]) from Lithuania and H. albicilla from Norway.ConclusionsThe white-tailed sea eagle (H. albicilla) acts as natural definitive host of S. arctica, whereas the common starling (St. vulgaris) and red kite (M. milvus) represent intermediate and definitive hosts, respectively, for S. halieti.

Molecular identification of Sarcocystis halieti in the muscles of two species of birds of prey from Spain

Background Members of the genus Sarcocystis are protozoan parasites characterized by a prey–predator two-host life-cycle. Sarcocysts are formed in the muscles or central nervous system of the intermediate host (IH), while sporocysts develop in the small intestine of the definitive host (DH). Various birds of prey have been confirmed to be DH for Sarcocystis spp. Three Sarcocystis species, S. wobeseri, S. halieti and S. falcatula, have been identified in the muscles of birds of prey, of which the latter are known to be pathogenic and can cause encephalitis in various birds. The aim of this study was to identify Sarcocystis spp. in the muscles of birds of prey from Spain. Methods Between 2019 and 2020, muscle tissue samples taken from 59 birds of prey admitted to the Wildlife Recovery Centre in Ilundain (Navarra, Spain) were examined for the presence of Sarcocystis spp. Sarcocysts in fresh squashed samples were morphologically characterized under the light microscope (LM). Sarcocystis spp. were identified by means of 28S ribosomal RNA and internal transcribed spacer 1 sequence analysis. Results Microscopic examination of squashed tissue samples stained with methylene blue revealed the presence of sarcocysts in three of the 59 (5.1%) birds examined. Only one sarcocyst type was observed under the LM. Sarcocysts were thread-like (1050–2160 × 130–158 μm) and had a thin (0.7–1.4 μm) and smooth cyst wall. Septa divided the cysts into compartments filled with banana-shaped (5.9 × 1.7 μm) bradyzoites. On the basis of DNA sequence results, S. halieti was identified in the western marsh harrier (Circus aeruginosus) and the black kite (Milvus migrans) for the first time. Sarcocysts of S. halieti were shorter and wider compared to those observed in the great cormorant (Phalacrocorax carbo) and the herring gull (Larus argentatus). According to current knowledge, S. halieti may infect birds belonging to four different orders: Suliformes, Charadriiformes, Strigiformes and Accipitriformes. Conclusions This is the first report of S. halieti in the western marsh harrier and the black kite as IH. So far, little research has been conducted on birds of prey as IH for Sarcocystis spp. These results indicate that further studies combining morphological, histopathological, and molecular methods are required. Graphical abstract

Comparison of metal burden in different muscle tissues of Great cormorant (Phalacrocorax carbo)

Concentrations of 12 metals (As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb and Zn) were examined in the pectoral and thigh muscle of great cormorants (Phalacrocorax carbo). The samples were collected from Central Tisza-Jászság Nature Conservation Area in Hungary. The tissue samples were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The aim of the study was to examine the impacts of heavy metal pollution on the water birds, determine the concentrations of the abovementioned metals in the different muscle tissues of these wetland birds, and provide the basic materials for monitoring the environmental pollution. Among the investigated elements/metals, the detected concentrations of As, Ba, Cd, Co, Cr, Mo and Ni were below the detection limit. Higher concentration of Cu, Hg, Mn and Pb was measured in the pectoral muscle compared to the thigh muscle, but only in the case of Cu and Mn were found significant differences between the tissues. In the case of the Zn concentration, the higher value was detected in the thigh muscle. There were no statistical differences between males and females in either metal concentrations.

Molecular Identification of Sarcocystis Halieti in Birds of Prey From Spain

Background: Members of the genus Sarcocystis are protozoan parasites characterized by a prey-predator two-host life cycle. Sarcocysts are formed in muscles or CNS of the intermediate host (IH), while sporocysts develop in the small intestine of the definitive host (DH). Various birds of prey were confirmed to be DH for Sarcocystis spp. By contrast, only two species, S. wobeseri and S. falcatula were identified in the muscles of birds of prey. The latter species is pathogenic and can cause encephalitis in various birds. The aim of the present study was to identify Sarcocystis species in the muscles of birds of prey from Spain. Methods: In the period between 2019 and 2020, muscle tissues of 59 birds collected from Spain were examined for the presence of Sarcocystis spp. Sarcocysts in fresh squashed samples were morphologically characterised under a light microscope (LM). Sarcocystis species were identified by means of 28S rRNA and ITS1 sequence analysis. Results: With the help of methylene blue-staining microscopic sarcocysts were detected in 3/59 (5.1%) birds of prey from Spain. Under LM, one type of sarcocysts was observed. Sarcocysts were thread-like (1050–2160 × 130–158 μm), had a thin (0.7–1.4 μm) and smooth cyst wall. Septa divided the cysts into compartments filled with banana-shaped (5.9 × 1.7 μm) bradyzoites. On the basis of DNA sequence results, S. halieti was identified in the western marsh harrier (Circus aeruginosus) and the black kite (Milvus migrans) for the first time. Sarcocysts of S. halieti detected in the black kite and the western marsh harrier were shorter and wider as compared to those observed in the great cormorant (Phalacrocorax carbo) and the herring gull (Larus argentatus). Hence, S. halieti might infect birds belonging to three different orders, Suliformes, Charadriiformes and Accipitriformes. Conclusions: This is the first report of S. halieti in birds of prey as IH. Due to the inconsistency of research on Sarcocystis spp. from birds of prey, further complex morphological, histopathological, and molecular studies are required.