Wild Bird Species Research Articles

The highly pathogenic avian influenza H5N8 sublineage 2.3.4.4b virus: A critical analysis of genetic steadiness based on full HA gene sequencing in Egypt

The highly pathogenic avian influenza virus (HPAIV) continues to be a significant threat to the poultry industry despite the implementation of vaccination programs. The main goal of this study was to explore the incidence of avian influenza viruses (AIVs) and the stability of the hemagglutinating (HA) gene sequence. For this drive, oropharyngeal swabs (n=425) were collected from various wild and domesticated bird species from 13 provinces in Egypt from 2019 to 2021. Viral isolation in specific pathogen-free chicken embryos revealed positive HA activity in 9.88% (n=32) of the wild and 36.37% (n=64) of domesticated species. Only eight H5N8 avian influenza viruses were delivered (4/each category) in mixed infection with Newcastle disease virus (NDV). Clinically, domesticated examined birds exhibited clinical findings suggesting avian influenza, but AIVs were delivered from both apparently healthy and sick wild birds. A/chicken-cobb/Egypt/55/2019(H5N8) sequence generated in this study has been submitted to GenBank under the accession number ON724339, and its in vivo pathogenicity was evaluated in four-week-old chickens, which revealed 90% mortality and typical clinical findings of HPAIV. Based on the full HA gene sequence, the strain has a Furin-sensitive cleavage site in the HA protein, which is an HPAIV. It has been clustered in clade 2.3.4.4b within AIVs from 2016 to 2023 and coexistence of genetically stable viruses 2016-2019 with 99.8-100% similarity. The existing strain is fully identical to three strains: A/green-winged teal/Egypt/877/2016(H5N8), A/northern shoveler/Egypt/MB-D-816OP/2016(H5N8), and A/duck/Egypt/N13736E/2017 (H5N8), with the only point of mutation at position 284 (G284E). In our analysis, the majority of H5NX AIV strains detected in Egypt since 2016 possessed 156T. As a result, there is evidence suggesting that H5N8 has been introduced sequentially through the migration of European wild birds along the Black Sea–Mediterranean and East Asia–West Africa flyways. This raises the possibility of future adaptation to mammals due to spillover from avian-origin strains, especially in native aquatic birds such as geese and ducks.

Emergence of highly pathogenic avian influenza viruses H5N1 and H5N5 in white-tailed eagles, 2021-2023.

Highly pathogenic avian influenza (HPAI) poses a substantial threat to several raptors. Between 2021 and 2023, HPAI viruses (HPAIVs) of the Goose/Guangdong lineage H5 clade 2.3.4.4b became widespread in wild birds in Norway, and H5N1 and H5N5 viruses were detected in 31 white-tailed eagles (Haliaeetus albicilla, WTEs). Post-mortem examinations of four WTEs revealed no macroscopic pathological findings. Microscopic examinations showed the presence of myocardial and splenic necroses and a few lesions in the brain. In situ hybridization revealed the presence of the virus in several organs, suggesting a multisystemic infection. The detection of HPAIV H5N5 in a WTE in February 2022 marked the first recorded occurrence of this subtype in Norway. Since then, the virus has persisted, sporadically being detected in WTEs and other wild bird species. Phylogenetic analyses reveal that at least two distinct incursions of HPAIV H5N1 Eurasian (EA) genotype C affected WTEs, likely introduced by migratory birds from Eurasia and seabirds entering from Western and Central Europe. Some WTE isolates from 2021 to 2022 clustered with those from Canada and Ireland, aligning with the transatlantic spread of H5N1. Others were related to the 2021 mass mortality of great skuas in the UK or outbreaks in seabird populations, including gannets, gulls and terns, during 2022 in the North Sea region. This suggests that the WTEs were likely preying on the affected birds. Our study highlights that WTEs can act as sentinels for some HPAIV strains, but the absence of several known circulating genotypes in WTEs suggests varying pathogenic effects on this species.

Seabird and sea duck mortalities were lower during the second breeding season in eastern Canada following the introduction of highly pathogenic avian influenza A H5Nx viruses

ABSTRACT Capsule H5N1 clade 2.3.4.4b viruses have caused significant mortality events in various wild bird species across Europe, North America, South America, and Africa. In North America, the largest impacts on wild birds have been in eastern Canada, where at least 40,391 wild birds were reported to have died from highly pathogenic avian influenza (HPAI) between April and September 2022. Aims To apply previously established methods to collect and quantify the total reported wild bird mortality in eastern Canada from October 2022 to September 2023. Methods We documented the spatial, temporal, and taxonomic patterns of wild bird mortality in the 12 months that followed a mass mortality event in the summer of 2022, and then quantified the observed differences in mortality across the spring and summer (April to September) of 2022 and 2023. In eastern Canada, there was high uncertainty about whether 2023 would bring another year of devastating HPAI-linked mortalities. Results Mortalities in the spring and summer of 2023 were 93% lower than in 2022, but encompassed a wider diversity of species. Mortalities in the fall/autumn and winter (non-breeding season) were dominated by waterfowl, while mortalities during the spring and summer (breeding season) were dominated by seabirds. Due to a low prevalence of HPAI among a subset of tested birds, we cannot broadly attribute the reported mortalities in 2023 to HPAI. However, our analysis did identify three notable mortality events linked to HPAI, involving at least 1646 Greater Snow Geese Anser caerulescens atlanticus, 232 Canada Geese Branta canadensis, and 212 Northern Gannets Morus bassanus. The latter reflected the continuation of a mortality event from the Northern Gannet’s 2022 breeding season. Conclusions This study emphasizes the ongoing need for H5Nx surveillance and mortality assessments as the patterns of mortality in wild populations continue to change.

Sperm Cryopreservation in Canaries to Protect Endangered Songbird Species: Comparison of Different Cryoprotectants.

Sperm cryopreservation is a rather complex process that needs to be adapted to wild and domestic bird species to ensure adequate efficiency. This study aimed to determine the usability of different cryoprotectants in the cryopreservation of Gloster canary sperm. For this purpose, sperm samples were collected from 12 2-year-old male Gloster canaries three times a week using cloacal massage for 4 weeks. After individual evaluation, sperm samples from the canaries were combined. Mixed sperm were divided into two groups in the study. Overall, 8% dimethyl sulfoxide (DMSO) and ethylene glycol (EG) were used as cryoprotectants. Sperm samples were drawn into straws after adding Dulbecco's Modified Eagle Medium (DMEM) extender with high glucose ratio and two different cryoprotectants in a 1:1 ratio and frozen to -80°C with liquid nitrogen vapour and then stored in liquid nitrogen at -196°C. Frozen-thawed semen samples were evaluated regarding motility, vitality, plasma membrane integrity (hypoosmotic swelling test [HOST]), density and abnormal spermatozoa rate. The highest motility value after freezing and thawing was determined in the EG group with 31.667%±4.773%. In addition, vitality, plasma membrane integrity and normal sperm morphology were statistically significantly higher in the EG-frozen group, whereas head and tail abnormality was low (p<0.05). This study determined that a DMEM extender containing 8% EG was more advantageous than a DMEM containing DMSO regarding spermatological parameters and could be used for long-term storage of canary sperm.

Wild Bird Species Structure and Feeding Guilds in Agricultural Area at Zagazig District, Sharkia Governorate, Egypt

Wild Bird Species Structure and Feeding Guilds in Agricultural Area at Zagazig District, Sharkia Governorate, Egypt

Phenotypic and molecular characterization of vancomycin resistant Enterococci from wild birds: First detection of a plasmid-borne vanC1 in Enterococcus faecalis.

Vancomycin-resistant enterococci (VRE) are a public health concern as they lead to therapeutic impasses and play a pivotal role in the dissemination of vancomycin resistance genes. As recent evidence suggests that wildlife can play a role in the dissemination of bacterial resistomes, this study explored the potential role of Algerian wild birds as a reservoir of VRE. A total of 222 cloacal and fecal samples were collected from various wild bird species and screened for VRE using a selective medium. Of the 47 isolated strains, 22 were identified as Enterococcus casseliflavus with the vanC2/C3 gene, 24 as Enterococcus gallinarum (19 carrying vanC1 and five carrying vanC2/C3), and one strain as Enterococcus faecalis with the vanC1 gene. Twenty-four (24) strains were multidrug-resistant with 61.7% resistant to rifampicin while no resistance to teicoplanin, linezolid and gentamicin was found. Additionally, 53.20% of the strains exhibited at least one virulence factor. To our knowledge, this study represents the first documentation of the vanC1 gene in E. faecalis isolated from wild birds. Furthermore, this gene was found to be carried by a conjugative plasmid, highlighting its ability to spread among bacterial populations and lead to the emergence of novel resistance phenotypes.

Avian malaria in a feral-pet pigeon: a case report

BackgroundAvian malaria is caused by diverse parasite species of the genus Plasmodium, and it affects various bird species. The occurrence of this disease in some wild bird species is sparsely documented due to the scarce availability of samples. Hence the pathogenicity in some hosts is not completely known. In addition, feral birds may act as reservoirs bridging the transmission cycle from wild migratory birds to domestic and zoo-kept bird species.Case presentationAn owner of pigeons adopted a feral pigeon (Columba livia forma domestica) and housed it together with his other pet-pigeons. The bird died unexpectedly a few weeks after a surgical procedure and necropsy revealed a severely anaemic carcass, with pale organs and hydropericardium. Histopathologic analysis revealed inflammatory infiltrates in the lung and liver, and monocytes and Kupffer cells contained haemozoin pigment indicative of phagocytosis of Plasmodium-infected erythrocytes. A high erythrocytic infection rate of 18% was evident in tissues and blood vessels in various organs. Furthermore, the thyroid had masses classified as thyroid carcinomas. Immunohistochemistry with anti- Plasmodium falciparum HSP70 antibody revealed positive signals in erythrocytes and intravascular leucocytes. Further microscopy analysis using a Hemacolor-stained impression smear revealed a high parasitaemia with an asynchronous infection showing all erythrocytic stages. Molecular diagnosis by PCR identified Plasmodium relictum, lineage GRW11 as the aetiological agent. The bird presented died most likely due to an acute infection as evidenced by the high blood parasitaemia, leading to major erythrocyte destruction. Further analyses of feral pigeons (n = 22) did not reveal any additional cases of Plasmodium infections.ConclusionThis study reports the first mortality associated with P. relictum lineage GRW11. The study supports previous studies, suggesting that Plasmodium infections are not frequent in pigeons. Host conditions like immunosuppression due to the tumour may have influenced the infection outcome in this fatal case. Use of anti-P. falciparum HSP70 antibody for detection of P. relictum antigens for immune assays in blood and tissue samples will be a useful tool for future studies.

Antimicrobial Susceptibility of Enterococci Isolated from Nestlings of Wild Birds Feeding in Supplementary Feeding Stations: The Case of the Canarian Egyptian Vulture.

Antimicrobial resistance is a growing concern worldwide, requiring a holistic "One Health" strategy to address the interconnectedness of human, animal, and environmental health. This study focused on Enterococci isolated from Canary Island Egyptian vulture chicks, an endangered species that feeds at supplementary feeding stations in the Canary Islands. Sampling and identification revealed the presence of several Enterococcus species, with a predominance of E. faecalis. Antimicrobial susceptibility testing showed resistance patterns, especially to important antibiotics such as quinolones, vancomycin, and linezolid. The prevalence of multidrug-resistant profiles was lower than that in other wild bird species. This study underscores the need for further research to understand the dynamics of antimicrobial resistance in wildlife and its implications for public health and conservation efforts, emphasizing the importance of a "One Health" approach to address this pressing problem.

A systematic review of laboratory investigations into the pathogenesis of avian influenza viruses in wild avifauna of North America.

The lack of consolidated information regarding the response of wild bird species to infection with avian influenza virus (AIV) is a challenge to both conservation managers and researchers alike, with related sectors also impacted, such as public health and commercial poultry. Using two independent searches, we reviewed published literature for studies describing wild bird species experimentally infected with avian influenza to assess host species' relative susceptibility to AIVs. Additionally, we summarize broad-scale parameters for elements such as shedding duration and minimum infectious dose that can be used in transmission modelling efforts. Our synthesis shows that waterfowl (i.e. Anatidae) compose the vast majority of published AIV pathobiology studies, whereas gulls and passerines are less represented in research despite evidence that they also are susceptible and contribute to highly pathogenic avian influenza disease dynamics. This study represents the first comprehensive effort to compile available literature regarding the pathobiology of AIVs in all wild birds in over a decade. This database can now serve as a tool to all researchers, providing generalized estimates of pathobiology parameters for a variety of wild avian families and an opportunity to critically examine and assess what is known and identify where further insight is needed.

Updates to the wild bird abundance and movement models for the early warning system for avian influenza in the EU

Abstract Highly pathogenic avian influenza (HPAI) viruses pose a significant threat to both poultry and wild bird populations. Migratory wild birds play a key role in the intercontinental spread of avian influenza (AI), introducing the virus into poultry populations. In response to frequent AI outbreaks in Europe, the European Food Safety Authority (EFSA), at the request of the European Commission (EC), produces quarterly and annual epidemiological reports to monitor and analyse AI trends. A key component of this surveillance includes the integration of outbreak data from Member States and contributions from non‐governmental ornithological organisations like the European Bird Census Council (EBCC) and the European Union for Bird Ringing (EURING) together in a predictive spatio‐temporal risk assessment model. Previous data integration and modelling efforts led to the development of an early warning system for predicting HPAI outbreaks accessible through a publicly available online user interface: the Bird Flu Radar. This report presents an improvement of the system by expanding the species coverage and refining the existing base models behind the epidemiological model. Specifically, this report details the exploration to incorporate 12 additional wild bird species into the models, and the changes made to the base models predicting the distribution and movements of wild birds. We demonstrate the improvements respecting the existing base models while at the same time enhancing the effectiveness in predicting HPAI outbreaks and possibly mitigating negative effects in Europe by providing more accurate predictions to different stakeholders.

Valid and accepted novel bacterial taxa isolated from non-domestic animals and taxonomic revisions published in 2023.

Continued investigation into the bacteria associated with non-domestic animals provides important information for recognizing normal flora, assessing the health status of these unique species of animals, and identifying new or emerging pathogens of concern. In this summary of novel taxa and taxonomic revisions, considerable additions have been made toward understanding fecal and mucosal flora in multiple wild animal species. In addition, novel pathogenic bacteria are discussed, including multiple Chlamydia spp. causing disease in a hawk and crocodile, two Corynebacterium spp. causing oral lesions in penguins and a lesser-known genus, Mergibacter within Family Pasteurellaceae, causing disease in multiple wild bird species. Finally, a few revisions to bacteria isolated from normal non-domestic animal body sites are mentioned.

Dioxins, PFOS, and 20 other Persistent Organic Pollutants in Eggs of Nine Wild Bird Species from the Vaal River, South Africa

The Vaal River catchment drains the largest and most populated industrial and mining region in Southern Africa. Heron, ibis, cormorant, egrets, and darter eggs, representing three habitats and four feeding guilds, were collected at four locations in 2009/10 to identify hotspots and hazards associated with persistent organic pollutants (POPs). The POPs included 21 organochlorine pesticides, five polybrominated diphenyl ether (PBDE) classes, 18 polychlorinated biphenyls (PCBs including six non-dioxin-like PCBs; NDL-PCB), and 12 dioxin-like PCBs (DL-PCBs), 17 polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs), and perfluorooctane sulfonate (PFOS). Aquatic predators had higher PFOS and PCDD/F concentrations, while PCBs dominated in terrestrial eggs. Organochlorine pesticides, PBDEs, and PCBs were strongly associated with eggs from the industrial regions, while PCDD/F concentrations were evenly distributed. PCDD/F and PCB toxic equivalency quotient concentrations were low with no adverse effects expected. PFOS peaked at Bloemhof Dam with a maximum of 2300 ng/g wm in an African Darter egg, indicating an unexpected PFOS hotspot, the source of which is unknown. Despite order of differences in compound class concentrations, there was no association with egg size. To the best of our knowledge, this is the only study that analysed all 2010 POPs in bird eggs on a large geographic scale. This study highlighted the importance of multi-species studies sampling from multiple locations to assess the risk that POPs pose to avian populations as hotspots and species at risk may be missed by studies looking at one or few species.

Genomic characterization of highly pathogenic H5 avian influenza viruses from Alaska during 2022 provides evidence for genotype-specific trends of spatiotemporal and interspecies dissemination

: The ongoing panzootic of highly pathogenic H5 clade 2.3.4.4b avian influenza (HPAI) spread to North America in late 2021, with detections of HPAI viruses in Alaska beginning in April 2022. HPAI viruses have since spread across the state, affecting many species of wild birds as well as domestic poultry and wild mammals. To better understand the dissemination of HPAI viruses spatiotemporally and among hosts in Alaska and adjacent regions, we compared the genomes of 177 confirmed HPAI viruses detected in Alaska during April – December 2022. Results suggest multiple viral introductions into Alaska between November 2021 and August or September 2022, as well as dissemination to areas within and outside of the state. Viral genotypes differed in their spatiotemporal spread, likely influenced by timing of introductions relative to population immunity. We found evidence for dissemination of HPAI viruses between wild bird species, wild birds and domestic poultry, as well as wild birds and wild mammals. Continued monitoring for and genomic characterization of HPAI viruses in Alaska can improve our understanding of the evolution and dispersal of these economically costly and ecologically relevant pathogens.

Molecular and pathological screening of the current circulation of fowlpox and pigeon pox virus in backyard birds

Avian pox is a disease that has devastating impacts on both poultry and wild bird species. Avian pox is caused by various strains of avipoxviruses (APV). Nevertheless, the virus has been detected in pigeons and chickens that are raised in backyard areas, leading to substantial financial damage for small-scale producers. There is a lack of comprehensive information regarding the transmission of APV among birds in the backyards and residential areas. Hence, the present investigation closely monitored and observed APV in domesticated birds residing in backyard areas, with the aim of impeding the transmission of the virus to nearby poultry farms. In 2023, a total of fifty backyard flocks were surveyed for the presence of avian pox disease. Sixteen backyards (14 pigeons and 2 chickens) exhibited warty nodular lesions on their heads and nonfeathered body parts. APV was confirmed in nodular lesions by polymerase chain reaction (PCR) amplification and genetic sequencing. All samples from the lesions showed successful amplification of the p4b locus (core protein p4b). Four confirmed samples were tested for pathogenicity on the chicken embryo chorioallantoic membrane (CAM). Histopathological examination revealed ballooning degeneration and numerous intracytoplasmic inclusion bodies (Bollinger bodies) in the ectoderm of the infected CAM. Phylogenetic analysis revealed that the strains clustered into main clade A, with 11 in subclade A2 and 5 in subclade A1. Amino acid identity showed 100% similarity between the vaccine (fowlpox/VSVRI/Egypt) and some detected strains (PP537574 and PP537575). In addition, the PP537576.1 to PP537580.1 and PP537582.1 to PP537585.1 had 2-point mutations compared to the fowlpox/VSVRI/Egypt vaccine. The overall finding of low biosecurity levels in the investigated backyard birds emphasizes the significance of establishing sanitary measures and control vectors to reduce virus transmission routes and disease severity. In conclusion, it is necessary to emphasize the tracking of APV in backyard birds. Concurrently, we advised enhancing hygiene protocols, vector management, and subsequent vaccination to restrict the occurrence of APV outbreaks and prevent their transmission to neighboring poultry farms. Furthermore, it is crucial to incorporate molecular studies in order to enhance the vaccine seeds for disease management.

Evolutionary drivers of sex-specific parasite prevalence in wild birds.

Males and females often differ in ecology, behaviour and lifestyle, and these differences are expected to lead to sex differences in parasite susceptibility. However, neither the sex differences in parasite prevalence, nor their ecological and evolutionary drivers have been investigated across a broad range of taxa using phylogenetically corrected analyses. Using the most extensive dataset yet that includes 755 prevalence estimates from 151 wild bird species in a meta-analytic framework, here we compare sex differences in blood and gastrointestinal parasites. We show that despite sex differences in parasite infection being frequently reported in the literature, only Haemoproteus infections were more prevalent in females than in males. Notably, only seasonality was strongly associated with the sex-specific parasite prevalence of both Leucocytozoon and Haemoproteus, where birds showed greater female bias in prevalence during breeding periods compared to the non-breeding period. No other ecological or sexual selection variables were associated with sex-specific prevalence of parasite prevalence. We suggest that much of the variation in sex-biased prevalence could be idiosyncratic, and driven by local ecology and behavioural differences of the parasite and the host. Therefore, breeding ecology and sexual selection may only have a modest influence on sex-different parasite prevalence across wild birds.

Quantitative Risk Assessment of Wind-Supported Transmission of Highly Pathogenic Avian Influenza Virus to Dutch Poultry Farms via Fecal Particles from Infected Wild Birds in the Environment.

A quantitative microbial risk assessment model was developed to estimate the probability that the aerosolization of fecal droppings from wild birds in the vicinity of poultry farms would result in the infection of indoor-housed poultry with highly pathogenic avian influenza virus (HPAIv) in the Netherlands. Model input parameters were sourced from the scientific literature and experimental data. The availability of data was diverse across input parameters, and especially parameters on the aerosolization of fecal droppings, survival of HPAIv and dispersal of aerosols were uncertain. Model results indicated that the daily probability of infection of a single poultry farm is very low, with a median value of 7.5 × 10-9. Accounting for the total number of poultry farms and the length of the bird-flu season, the median overall probability of at least one HPAIv-infected poultry farm during the bird-flu season is 2.2 × 10-3 (approximately once every 455 years). This is an overall estimate, averaged over different farm types, virus strains and wild bird species, and results indicate that uncertainty is relatively high. Based on these model results, we conclude that it is unlikely that this introduction route plays an important role in the occurrence of HPAIv outbreaks in indoor-housed poultry.

Mapping the risk of introduction of highly pathogenic avian influenza to Swedish poultry

Outbreaks of highly pathogenic avian influenza (HPAI) have resulted in severe economic impact for national governments and poultry industries globally and in Sweden in recent years. Veterinary authorities can enforce prevention measures, e.g. mandatory indoor housing of poultry, in HPAI high-risk areas. The aim of this study was to conduct a spatiotemporal mapping of the risk of introduction of highly pathogenic avian influenza virus (HPAIV) to Swedish poultry from wild birds, utilising existing data sources. A raster calculation method was used to assess the spatiotemporal risk of introduction of HPAIV to Swedish poultry. The environmental infectious pressure of HPAIV was first calculated in each 5 km by 5 km cell using four risk factors: density of selected species of wild birds, air temperature, presence of agriculture as land cover and presence of HPAI in wild birds based on data from October 2016-September 2021. The relative importance of each risk factor was weighted based on opinion of experts. The estimated environmental infectious pressure was then multiplied with poultry population density to obtain risk values for risk of introduction of HPAIV to poultry. The results showed a large variation in risk both on national and local level. The counties of Skåne and Östergötland particularly stood out regarding environmental infectious pressure, risk of introduction to poultry and detected outbreaks of HPAI. On the other hand, there were counties, identified as having higher risk of introduction to poultry which never experienced any outbreaks. A possible explanation is the variation in poultry production types present in different areas of Sweden. These results indicate that the national and local variation in risk for HPAIV introduction to poultry in Sweden is high, and this would support more targeted compulsory prevention measures than what has previously been employed in Sweden. With the current and evolving HPAI situation in Europe and on the global level, there is a need for continuous updates to the risk map as the virus evolves and circulates in different wild bird species. The study also identified areas of improvement, in relation to data use and data availability, e.g. improvements to poultry registers, inclusion of citizen reported mortality in wild birds, data from standardised wild bird surveys, wild bird migration data as well as results from ongoing risk-factor studies.

A(H5N1) Avian Influenza Virus: A New Pandemic Threat on the Horizon?

The present Editorial deals with the highly pathogenic avian influenza (HPAI) virus A(H5N1), whose clade 2.3.4.4b has been identified in several domestic and wild bird and mammalian species, both terrestrial and aquatic, with mass mortality outbreaks also affecting South American sea lions. Within this fast evolving scenario, the progressively and consistently expanding range of virus-susceptible host species alongside the prominent viral neurotropism and neuropathogenicity are a matter of concern, with A(H5N1) virus having additionally spread among USA cattle, which may also shed it through their milk. Although it is not happening at the moment, the possibility A(H5N1) virus may sooner or later become easily transmissible between people appears to be largely plausible. A collaborative, intersectorial and multidisciplinary approach, based upon the "One Health" concept/principle is strongly needed in order to properly counteract the global menace brought about by the HPAI A(H5N1) virus, thereby taking inspiration from the lessons learned during the COVID-19 pandemic.

Morphological and molecular identification of Sarcocystis falcatula from the emerald toucanet (Aulacorhynchus albivitta) in Colombia

Sarcocystis spp. are cyst-forming coccidia characterized by a two-host predator-prey life cycle. Sarcocysts are formed in muscles or nervous system of the intermediate host, while sporocysts develop in the small intestine of the definitive host. The intermediate hosts of Sarcocystis falcatula are wild birds. Colombia is one of the countries with the greatest biodiversity of birds, however, there are few studies related to this parasite in wild birds. This study presents the morphological and molecular detection of Sarcocystis falcatula collected from the emerald toucanet (Aulacorhynchus albivitta), a wild bird species endemic to South America. Pectoral muscle samples were obtained, and microscopic and molecular detection was performed by light microscopy, transmission electron microscopy, and amplifying of the first internal transcribed spacer (ITS-1) and surface antigen-encoding genes (SAGs). Sarcocystis measured an average of 161 × 42 μm, with a cyst wall ∼0.4 μm thick. Ultrastructurally, the sarcocyst wall type 11b-like consisted of numerous villar protrusions of 850 nm wide on average. The ITS-1 sequence showed 97.0–99.7% identity to S. falcatula previously described from birds in the United States and Brazil, respectively. Concatenated phylogenetic analysis based on SAG2, SAG3 and SAG4 confirmed that the new isolate is grouped with other sequences of Sarcocystis from South America, but divergent from those isolates obtained in North America. The results of this study demonstrate for the first time the presence of S. falcatula in a wild bird from Colombia.

Characterizing the domestic-wild bird interface through camera traps in an area at risk for avian influenza introduction in Northern Italy

Direct or indirect interactions between sympatric wildlife and poultry can lead to interspecies disease transmission. Particularly, avian influenza (AI) is a viral epidemic disease for which the poultry-wild bird interface shapes the risks of new viral introductions into poultry holdings. Given this background, the study hereby presented aimed to identify wild bird species in poultry house surroundings and characterize the spatiotemporal patterns of these visits. Eight camera traps were deployed for a year (January to December 2021) in three commercial chicken layer farms, including free-range and barn-type setups, located in a densely populated poultry area in Northern Italy at high risk for AI introduction via wild birds. Camera traps’ positions were chosen based on wildlife signs identified during preliminary visits to the establishments studied. Various methods, including time series analysis, correspondence analysis, and generalized linear models, were employed to analyze the daily wild bird visits. A total of 1,958 camera trap days yielded 5,978 videos of wild birds from 27 different species and 16 taxonomic families. The animals were predominantly engaged in foraging activities nearby poultry houses. Eurasian magpies (Pica pica), ring-necked pheasants (Phasianus colchicus) and Eurasian collared doves (Streptopelia decaocto) were the most frequent visitors. Mallards (Anas platyrhynchos), an AI reservoir species, were observed only in a farm located next to a fishing sport lake. Time series analysis indicated that wild bird visits increased during spring and winter. Farm and camera trap location also influenced visit frequencies. Overall, the results highlighted specific species that could be prioritized for future AI epidemiological surveys. However, further research is required to assess their susceptibility and infectivity to currently circulating AI viruses, essential for identifying novel bridge hosts.