Search Results (234)

Blastocystis spp. is an enteric protist that is present worldwide. Despite being discovered a century ago, there is still much to be learned about its pathogenicity and transmission. Different subtypes (ST) of Blastocystis spp. have been identified in various hosts, including humans, birds, and insects, and there is potential for zoonotic transmission through contact between humans and animals. The prevalence of Blastocystis spp. in humans and macaques in Singapore was understudied, and the findings revealed a significant prevalence of the parasite, with rates of 90% and 100% observed in each respective Macaca fascicularis population 1 and 2, with main subtypes (ST1, ST2, ST3, and ST5). Using metagenomics, the different subtypes of Blastocystis spp. (comprising ST2, ST3, and ST17) were identified in a healthy Singaporean cohort. Additionally, seven incidental findings of Blastocystis spp. were discovered in human patients with other gut parasites, including two ST1, two ST2, two ST3, and one ST8. Several factors such as diet or reverse zoonotic transmission are suggested to play a role in Blastocystis sp. subtype distribution. Full article

Feather mites play an important role in bird communities, covering a wide spectrum of associations with their hosts, ranging from parasitic to mutualistic relations. As a result of long co-evolution with their warm-blooded hosts, this diverse group of arthropods can be found in a wide range of environments where their hosts occur, including the high Arctic. The feather mite fauna of Greenland is poorly known. Herein, we present new data on feather mites found on three species of passerine birds, which were captured on Disko Island (Qeqertarsuaq), West Greenland. The feather mite species Analges longispinosus was found on Snow Bunting (Plectrophenax nivalis); Proctophyllodes plectrophenax on Snow Bunting and Lapland Longspur (Calcarius lapponicus); and Proctophyllodes hipposideros on Northern Wheatear (Oenanthe oenanthe). The two Proctophyllodes species represent new records for Greenland. Further studies are needed to reveal the diversity of feather mite species in this remote Arctic region. Full article

Laminosioptes cysticola (Vizioli, 1870), a tissue-dwelling mite responsible for nodular acariasis in birds, was identified from two hens reared in a rural backyard flock in Umbria, Italy. Adult mites were found in the subcutaneous tissue and on the serosal surface of various internal organs. Larval and first- and second-stage nymphal forms were observed beneath the skin and near the trachea and esophageal serosa. By comparing the existing literature with that reported in the present study, we propose a hypothetical reconstruction of the parasite’s life cycle. It is postulated that the entry of L. cysticola occurs through the cervical skin, where adults mate and larviparous females give birth to larvae. These larvae migrate into the loose connective tissues surrounding the trachea and esophagus, where they develop into nymphs. The immature forms then progress along the esophagus and trachea to reach the thoracic and abdominal cavities, colonizing the serosal surfaces of visceral organs. It remains unclear whether, or how, the mites return to the subcutaneous tissues to complete their maturation. Senescent specimens degenerate within the subcutis, where they are encased by a granulomatous inflammatory reaction that leads to the formation of characteristic calcified nodules. Full article

Seabirds of the families Fregatidae, Phalacrocoracidae and Sulidae, common on the southeastern coast of Brazil, form colonies and play a bioindicator role in coastal ecosystems due to their ecological habits. This study aimed to identify the prevalence of parasitic helminths in Suliformes birds, of the species Fregata magnificens Mathews, 1914, Sula leucogaster Boddaert, 1783 and Nannopterum um Gmelin, 1789, from the Instituto de Pesquisas Cananeia (IPeC) on the southern coast of the State of São Paulo, and to record the diversity and parasitic indices, since reports of helminth prevalence in pelagic birds are scarce in Brazil. From 2018 to 2020, a total of 270 nematode specimens and 271 acanthocephalan parasites were collected from 51 Suliformes birds (20 F. magnificens, 10 N. brasilianum and 21 S. leucogaster). The host species F. magnificens was parasitized by Contracaecum plagiaticium and Contracaecum pelagicum. The host S. leucogaster was parasitized by C. plagiaticium. In the host N. brasilianum, specimens of Contracaecum australe, Contracaecum rudolphii, Contracaecum multipapillatum, Syncuaria squamata and Andracantha tandemtesticulata were found. This is the first report of C. plagiaticium and C. pelagicum in F. magnificens in Brazilian territory, and of A. tandemtesticulata in N. brasilianum in the southeast region of Brazil. Full article

The apicomplexan parasite Toxoplasma gondii can potentially infect all warm-blooded animals, including birds, which, due to their high dispersal capabilities, are considered a significant candidate group of sentinel animals that reveal environmental contamination with this protozoan. In the present study, the serologic and molecular prevalences of T. gondii infection were determined in 333 corvids from Romania. Paired meat juice (n = 333) and heart samples (n = 244) were collected and analyzed using the modified agglutination test for antibodies, polymerase chain reaction (PCR) for DNA, and SAG2 molecular marker sequencing for genotyping. The overall T. gondii antibodies prevalence was 19.5%, with 48.1% infected jackdaws, 72.8% rooks, 89.7% hooded crows, 77.5% magpies, and 42.9% jays. Of 244 heart samples analyzed with PCR amplification, only 3 (1.2%) resulted positive and were shown to belong to genotype III through the sequencing of the SAG2 amplicon. This is the first extensive study on T. gondii in crows from Romania. Full article

Birds are hosts to a diverse assemblage of vector-transmitted haemosporidian parasites. However, the true genetic diversity and many host–parasite interactions are still unknown, particularly in under-represented species groups such as wild doves and pigeons (Columbiformes). In this study, we examined the prevalence and lineage diversity of haemosporidian genera Plasmodium, Leucocytozoon, and Haemoproteus in three species of wild columbids, sampled in Germany. Examinations were performed by applying molecular methods (nested PCR and one-step multiplex PCR) and blood smear examination, and their respective advantages and disadvantages are discussed. In the case of the European Turtle Dove Streptopelia turtur, samples were collected along a west–east gradient throughout Germany, covering migratory birds from the Western and Central-Eastern flyway of this species. Although no infection was detected in the Stock Dove Columba oenas samples, 53% of Turtle Dove and 86% of Common Woodpigeon Columba palumbus harbored a parasite of at least one haemosporidian genus, revealing previously unknown lineage–host interactions. We were not able to demonstrate a correlation between infection status (presence or absence of infection based on PCR results) and parasitemia with condition based on the heterophil to lymphocyte ratio (H/L ratio). Neither lineage occurrence nor prevalence of infection followed any geographically specific patterns. Thus, haemosporidian lineages found in Turtle Doves could not be used as a marker of geographic origin that would allow the tracking of their nonbreeding distribution. Full article

Baylisascariasis is a debilitating and potentially lethal zoonotic disease caused by a nematode parasite that has a worldwide distribution. Baylisascaris spp. are carried by a variety of mammalian definitive hosts, and their larvae can infect a large diversity of paratenic hosts including birds and mammals, and even humans. Herein, the potential exposure risk of this zoonotic parasite is demonstrated through the study of a suburban American community with a population of Baylisascaris procyonis—infected raccoons (Procyon lotor) as a case study for any location with Baylisascaris spp., definitive hosts, and proximity to humans. Soil from 100 properties within neighborhoods of southern Corpus Christi, TX, USA, was surveyed to determine if viable B. procyonis eggs were present. In total, 27% of the residential properties were contaminated. Positive soil samples, on average, contained 31,287 B. procyonis eggs/gram of soil; of these samples, 92% of the B. procyonis eggs had motile larvae. Sites with contaminated soils appeared random within residential properties; frequency of contaminated sites was similar between known raccoon defecation sites and random sites. Suggestions for the reduction in risks of exposure to this potentially debilitating parasite are offered to residents of Baylisascaris-contaminated properties. Full article

Bird eyes are more neglected organs in studies targeting the structure of the helminth fauna, which are instead mainly focused on the digestive and respiratory systems. In an extended study aimed at identifying helminths in the common buzzard (Buteo buteo), the eyes of 92 birds were also examined. Morphological characteristics and molecular analyses were used to identify the collected specimens. Eyeworms were found in only one bird, a juvenile male (1/92; 1.08%). Two nematodes were collected, a female and a fourth-stage larva. This is the first report of Oxyspirura petrowi in the common buzzard. The results highlight the need for careful examination of raptors’ eyes as ocular parasitism can affect their vision. Full article

Fish-borne parasites encompass diverse taxonomic groups, including nematodes of the genus Eustrongylides (family Dioctophymatidae), which infect fish, fish-eating birds, and, occasionally, humans. Eustrongylides spp. are globally distributed, with E. ignotus and E. tubifex prevalent in North America, while E. excisus is more frequent in Europe and the Middle East. This study investigates the presence of E. excisus in a fish community of the Po River (Turin, northwest Italy). Among 170 fish sampled from three sites along the Po River, only two Padogobius bonelli individuals from the Murazzi site were found to be infected, each hosting a single larva within the abdominal cavity. Molecular analysis (ITS rDNA sequencing) confirmed the parasite as E. excisus, showing 100% identity with known sequences. Although prevalence in this study was low (1.18%), the findings significantly expand the known host range of E. excisus, previously reported only in other gobiid species in Eastern Europe. The parasite is widely distributed in Italy, especially in commercial fish from large lakes, and its spread is facilitated by oligochaete intermediate hosts and piscivorous birds like cormorants. Given the benthic habits and diet of P. bonelli, increased monitoring is needed to better understand the parasite’s transmission dynamics and the potential risks to native biodiversity and human health. Full article

Culicoides biting midges (Diptera: Ceratopogonidae) are important vectors of avian haemosporidian parasites. Understanding their host preferences is crucial for elucidating transmission routes of vector-borne pathogens. In Slovakia, such knowledge is limited, particularly in forested wetlands. This study aimed to identify Culicoides species, their host preferences, and haemosporidian parasites in a wetland ecosystem at the Bird Ringing Station in Drienovec. Midges were collected in 2022 using UV light traps at two sites. In total, 2344 Culicoides individuals of 19 species were collected. Host blood was identified and DNA subsequently extracted from 36 engorged females, revealing feeding on three mammal and five bird species. The most frequently identified host was roe deer (Capreolus capreolus), predominantly fed upon by Culicoides obsoletus (Meigen 1818). Notably, avian haemosporidian DNA was detected for the first time in Slovakia in three Culicoides females. In two Culicoides alazanicus Dzhafarov 1961 individuals, DNA of Haemoproteus asymmetricus (TUPHI01) and Plasmodium matutinum (LINN1) was confirmed, both associated with avian blood from Turdus sp. One Culicoides festivipennis Kieffer 1914 female carried Haemoproteus tartakovskyi (HAWF1) and fed on Coccothraustes coccothraustes. These findings highlight the potential role of local Culicoides species in transmitting avian pathogens and underscore the importance of monitoring their ecology. Full article

Coccidian parasites possess complex life cycles involving asexual proliferation followed by sexual development, producing oocysts that are transmitted from host to host through feces, guaranteeing disease transmission. Eimeria necatrix is a highly pathogenic coccidian causing high mortality in birds. This study examined ultrastructural changes occurring during the third merogony, microgametogenesis, and macrogametogenesis of E. necatrix. The third-generation meront contained eight merozoites, each with coccidian-specific features like conoid, rhoptries, micronemes, and dense granules. Microgametes had a nucleus, mitochondrion, two flagella, and a basal apparatus. Macrogametes surrounded by two membranes (M1 and M2), contained organelles like WFB1, WFB2, endoplasmic reticulum, mitochondria, and tubular structures. Oocyst wall formation began with M2 separating from M1 and forming a loose veil around the organism. The WFB1 fused together to form the outer layer of the oocyst wall between M1 and M2, while M4 formed beneath M1. The WFB2 fused with the M4 to discharge its contents external to M4, which fused together to form the inner layer of the oocyst wall. Immunogold electron microscopy co-localization result showed that EnGAM22 localized to WFB1 and the outer wall, while EnGAM59 localized to WFB2 and the inner wall, suggesting they are key structural components of the oocyst wall. Full article

Gastrointestinal parasites impact the health and productivity of domestic birds and may even be more common in production systems with lower biosafety conditions. In this context, backyard poultry production systems (BPPS), defined as small-scale family production systems, could be more affected. However, information about its epidemiology is limited in the Central Zone of Chile. This study aimed to determine the risk factors and spatial distribution of gastrointestinal parasites in BPPS in Central Chile. Thus, feces samples were collected from 51 backyards and analyzed using copro–parasitological techniques. In parallel, an epidemiological survey was conducted on the farmers, and the data were analyzed by multivariable logistic regression to identify risk factors. Spatial analysis was performed with the detected parasite species to determine high-risk clusters. Eimeria spp. was the most frequently detected parasite (72.5%), followed by Capillaria spp. (50.9%) and Ascaridia galli (49%). Regarding parasitic burden, nearly 90% of BPPS showed low parasitic burden for Eimeria spp. and helminths. In turn, the availability of potable drinking water (95% CI: 0.054–0.905; p = 0.036) and proper ventilation of the pens (95% CI: 0.003–0.429; p = 0.009) reduced the presence of parasites. Spatial high-risk clusters were detected for Eimeria spp. (RR = 2.60; p-value < 0.0001), A. galli (RR = 2.93; p-value = 0.021), and Trichostrongylus spp. (RR = 5.85; p-value = 0.050). Full article

Passerine birds (n = 3335) of 19 species were caught and investigated for the presence of Trypanosomatidae and Onchocercidae parasites using the buffy coat method, microscopy and PCR in Ventės Ragas, Lithuania. Data on the spread patterns of these parasites are still lacking. The prevalences of Trypanosoma parasites in birds of different species varied from 2.2% to 36.1%, while the prevalences of Onchocercidae parasites varied from 0% to 17.3%. Statistically significant differences between spring and autumn in the prevalences of Trypanosomatidae were determined for Acrocephalus schoenobaenus, Hirundo rustica and Turdus philomelos. No significant differences between the prevalences of Onchocercidae in spring and autumn were determined. The prevalence of Trypanosoma was significantly higher for long-distance migrant birds compared with short-distance migrants, for omnivorous birds compared with insectivorous birds, and for open-nesting birds compared with birds nesting in nest boxes. The prevalences of Onchocercidae parasites did not differ for the same bird groups except for the prevalence in omnivorous birds, which was higher compared with insectivorous birds. Both groups of parasites were detected in juveniles, showing the presence of transmission in the study area. The diet, breeding behaviour and migration features of avian hosts can influence the prevalence of avian blood parasites. Full article

Trypanosoma cruzi, the protozoan causative of Chagas disease, is primarily transmitted through blood-sucking insects and infects mammalian and some reptilian hosts. In Chile, insects of the Mepraia genus are key vectors of T. cruzi in its wild transmission cycle. High prevalence and mixed infection of T. cruzi lineages have been reported in a Mepraia population on Santa María Island in the Atacama Desert. However, no small mammals have been reported. The island’s vertebrate community is dominated by the lizard Microlophus atacamensis and marine and scavenger birds. This study aimed to research blood samples of M. atacamensis for the presence of T. cruzi DNA (kDNA and satDNA) using conventional PCR (cPCR) and quantitative real-time PCR (qPCR) and estimate parasitemia. Our findings reveal that 39.4% of 33 individuals were positive with both cPCR and qPCR, while when assessing infection with either technique, it rises up to 81.8%. These findings confirm that M. atacamensis is a host of T. cruzi, suggesting its potential role as a key reservoir in the island’s transmission cycle. This study provides new insights into the life cycle of T. cruzi in the coastal Atacama Desert, highlighting the importance of reptiles in the epidemiology of this parasite. Full article

Haemosporidian parasites (Apicomplexa, Haemosporida) are diverse obligatory heteroxenous protists, which infect all major groups of terrestrial vertebrates and use dipterous blood-sucking insects as vectors. These pathogens are responsible for various diseases, including malaria, which remains an important human and animal illness. In the wild, haemosporidians are particularly diverse in reptiles and birds in tropical countries, where they are flourishing. Avian haemosporidians have been particularly extensively investigated, especially due to their high prevalence and global distribution, including the countries with cold climates. The general scheme of the life cycle of haemosporidians is known, but the details of development remain insufficiently investigated or even unknown in most of the described parasite species, suggesting the existence of knowledge gaps. This attracts attention to some recent observations, which remain fragmentary but suggest the existence of formerly neglected or underestimated modes of the haemosporidians’ survival in vertebrates. Such findings are worth discussion as they indicate the novel directions in wildlife haemosporidian research. This article overviews some recent findings, which call for broadening of the orthodox views on modes of existence of haemosporidian parasites in avian hosts. Among them are the role of blood merogony in the long-lasting persistence of malaria parasites in birds, the role of gametocytes in the long-lasting survival of Haemoproteus species in vertebrates, the possible reasons of undetectable avian Haemoproteus infections due to peculiarities of exo-erythrocytic development, and the plausible factors driving the narrow vertebrate host specificity of Haemoproteus species. Full article