Wild Ducks Research Articles

Discovery and Genomic Characterisation of Novel Papillomaviruses in Australian Wild Birds

Papillomaviruses are small, circular DNA viruses that infect epithelial and mucosal cells, which have co-evolved with their hosts over time. While certain mammalian papillomaviruses—especially those linked to disease—are well studied, there is limited knowledge about papillomaviruses associated with avian species. In this study, we identified two avian papillomaviruses from eye/choana swabs of the sacred kingfisher (Todiramphus sanctus) and the little corella (Cacatua sanguinea), collected in Queensland, Australia. The genomes of these viruses, designated as todiramphus sanctus papillomavirus 1 (TsPV1) and cacatua sanguinea papillomavirus 1 (CsPV1), were found to be 7883 and 7825 base pairs in length, respectively. The TsPV1 and CsPV1 genomes exhibited the highest nucleotide sequence identity (>56%) with papillomavirus genomes previously sequenced from mallards or wild ducks in the United States, followed by those from black-legged kittiwakes and Atlantic puffins (>54%) in Newfoundland, Canada. Both TsPV1 and CsPV1 share approximately a 65% nucleotide sequence identity in the L1 gene with anas platyrhynchos papillomavirus 3 (AplaPV3), indicating that they represent novel avian papillomaviruses. Notably, the two genomes in this study were nearly identical (99.69%), and their L1 proteins shared 100% sequence identity. Phylogenetic analysis positioned TsPV1 and CsPV1 within a clade of avian papillomaviruses associated with closely related avian hosts, including the mallard, African grey parrot, common chaffinch, and Atlantic canary. These findings underscore the importance of further research on studying additional Australian bird species longitudinally, which will help to establish potential disease associations and ecological impacts of previously unrecognised and novel papillomaviruses in Australian wild birds.

Temperature-driven metabolic shifts in duck egg components during early embryogenesis: from diapause to active developmental phase

Embryonic diapause, a survival strategy observed in birds such as wild ducks (where entire clutches may suspend development), allows embryos to delay growth under suboptimal conditions. In commercial practices, this trait is harnessed to synchronise hatching with market schedules, maximising production efficiency. We propose that temperature-driven reactivation of diapause involves metabolic responses linked to dynamic small molecule profiles in yolk and albumen, potentially regulating embryonic resumption. Using 12 duck eggs divided equally into experimental and control groups, we conducted untargeted metabolomics to profile metabolic dynamics during the 48-h diapause-to-embryogenesis transition across pre- and post-incubation phases. Differential metabolite analysis in yolk and albumen was integrated with KEGG pathway enrichment to identify functional shifts linked to embryonic reactivation. In our study, we identified 17 and 22 differentially abundant metabolites in yolk and albumen, respectively, with upregulated Arachidonic acid and downregulated N-acetylserotonin in yolk and upregulated ketoleucine in albumen, implicating roles in embryonic development via signalling, amino acid metabolism and antioxidant functions. The KEGG analysis uncovered enriched pathways, including Tryptophan metabolism, Branched-Chain Amino Acids (BCAA) biosynthesis and ATP-binding cassette (ABC) transporters, which may play pivotal roles in initiating duck embryo development. We speculate that tryptophan and branched-chain amino acid metabolism influence embryo development through protein synthesis regulation, combined with ABC transporter-mediated nutrient allocation during temperature shifts. The enrichment of Arachidonic acid in Gonadotropin-releasing Hormone (GnRH) signalling pathway might suggest its role in critical processes. Our findings may help refine incubation practices and breeding outcomes by understanding duck embryo diapause mechanisms.

Chicken Consumption in Three Early Modern (17th–19th Century) Cities in Japan

ABSTRACTChickens (Gallus gallus domesticus) were introduced to Japan in the middle Yayoi period (fourth to third centuries BCE), but widespread consumption did not occur until the Edo period (17th to 19th centuries) based on historical documents and archaeological material. To clarify how chicken consumption became popular in early modern Japan, this study analyzed bird remains recovered from sites in three cities: Edo (early modern Tokyo), Nagasaki, and Osaka. We focused on temporal changes and regional differences in the frequency of chicken bones and the growth stages and sex ratios of chickens targeted for consumption. Our findings revealed that the most frequently consumed birds in Edo City during the 17th and 18th centuries were wild ducks and geese. Chicken consumption increased in the Edo period during the 19th century, particularly in samurai residences. By contrast, chicken consumption was popular among the townspeople in Nagasaki and Osaka and among Dutch merchants in Nagasaki since the 17th century. At the former residences of samurai and townspeople in Edo City and Osaka, most of the chickens consumed were male, mature birds, with an increase in the consumption of hens and juvenile chickens in Edo City by the 19th century. Conversely, juvenile chickens and hens were consumed more frequently in Nagasaki than in other cities since the 17th century. These findings suggest regional differences in the spread of chickens as part of the diet consumption and the age and sex of the birds consumed in early modern Japan.

Genotype I Newcastle Disease Virus, Isolated from Wild Duck, Can Protect Chickens Against Newcastle Disease Caused by Genotype VII.

Newcastle disease viruses (NDVs) circulating among wild birds and poultry may differ in virulence. Some NDVs cause devastating outbreaks in chickens. The NDV/duck/Moscow/3639/2008 (d3639) strain was isolated from a wild duck. Its genome was sequenced (PP795281, GenBank) and the biological properties, specifically for infection in chicken and mice, were studied. Strain d3639 of genotype I.2 has an F protein cleavage site (112-GKQGRL-117) and a HN protein length (616 a.a.) of the lentogenic pathotype. It was tested, in comparison with the genotype II LaSota vaccine strain, for its immunogenicity and protective efficacy against a challenge with the velogenic NDV strain NDV/chicken/Moscow/6081/2022 (ch6081) of sub-genotype VII.1.1, the complete genome of which was also sequenced in this study (PP766718, GenBank). Both the d3639 and LaSota viruses did not induce clinical signs in chickens or mice. Single immunization was performed by inoculation through drinking water with the live virus. Inoculation protected the chickens during a subsequent challenge with velogenic ch6081 and significantly reduced shedding in feces. Double immunization was sufficient to achieve prolonged immunity and prevented the shedding of the velogenic virus after the challenge. Thus, this natural lentogenic d3639 virus possesses properties similar to the LaSota vaccine strain and can protect against sub-genotype VII.1.1 NDV.

Nine high-quality Anas genomes provide insights into Anas evolution and domestication.

Nine high-quality Anas genomes provide insights into Anas evolution and domestication.

Deglycosylation and truncation in the neuraminidase stalk are functionally equivalent in enhancing the pathogenicity of a high pathogenicity avian influenza virus in chickens

Influenza A viruses with fewer amino acids in the neuraminidase (NA) stalk domain are primarily isolated from chickens rather than wild ducks, indicating that a shortened NA stalk is considered an adaptation marker of avian influenza viruses (AIVs) to chickens. Experimental passages of an H7N7 nonpathogenic AIV (rgVac2-P0) in chickens resulted in a highly pathogenic variant (Vac2-P3L4) with a 34-amino-acid deletion in the NA stalk, encompassing five potential N-glycosylation sites. To investigate how amino acid truncation and deglycosylation in the NA stalk contribute to increased pathogenicity, a virus with glycosylation-deficient mutations at these sites (rgVac2-P3L4/P0NAΔGlyco) was constructed. Contrary to expectations, chickens inoculated with rgVac2-P3L4/P0NAΔGlyco exhibited variable clinical outcomes, attributed to the genetic instability of the virus. A single mutation stabilized the virus, and the mutant (rgVac2-P3L4/P0NAΔGlyco-Y65H) resulted in higher pathogenicity compared with a virus with restored glycosylation (rgVac2-P3L4/P0NA-Y65H). Glycan occupancy analysis revealed 3-4 glycans at the five potential sites. In functional analysis, glycosylation-deficient mutants, similar to the short-stalk NA virus, showed significantly reduced erythrocyte elution activity. Additionally, mutational analysis indicated variable contributions of N-glycans to elution activity across the sites. Moreover, the functionally most contributing sites of the five potential N-glycosylation motifs were consistently included in the amino acid deletions of the stalk-truncated NA in N7-subtyped field isolates, despite the varying truncation position or length. These findings suggest that the loss of glycosylation is functionally equivalent to a reduction in amino acids, and it plays a crucial role in enhancing pathogenicity in chickens and affecting NA function.IMPORTANCEAvian influenza poses significant economic challenges to the poultry industry and presents potential risks to human health. Understanding the molecular mechanisms that facilitate the emergence of chicken-adapted avian influenza viruses (AIVs) from non-pathogenic duck-origin influenza viruses is crucial for improving AIV monitoring systems in poultry and controlling this disease. Amino acid deletions in the neuraminidase (NA) stalk domain serve as one of the molecular markers for AIV adaptation to Galliformes. This study highlights the critical role of N-glycosylation in the NA stalk domain in the pathogenesis of high pathogenicity avian influenza viruses in chickens. The findings propose a novel theory that the loss of glycosylation at the NA stalk domain, rather than a reduction in stalk length, is responsible for both NA function and increased virus pathogenicity in chickens.

Wild Florida mottled ducks demonstrate strong heterogeneity in their humoral innate immune response.

The Florida Mottled Duck (Anas fulvigula fulvigula) is a unique subspecies of waterfowl whose range is limited to peninsular Florida, USA. As an endemic subspecies, Florida Mottled Ducks face numerous conservation stressors, such as habitat conversion and hybridization with non-native Mallards (Anas platyrhynchos). In addition to these numerous stressors, Mottled Ducks are also contending with emerging and/or geographically expanding waterborne pathogens such as Vibrio spp., due to the effects of climate change. However, even given their conservation needs, little is known with respect to the health, physiology, and the immunity of wild Mottled Ducks in Florida. Given this lack of data, we performed health assessments of Mottled Ducks in the Central Florida area. Specifically, we examined the humoral innate immune system, i.e., the plasma of Mottled Ducks in response to a common but extraneous pathogen: Escherichia coli strain American Type Culture Collection (ATCC) number 8739. We utilized a bactericidal assay ("bacterial killing assay" or BKA) commonly used in eco-immunology, to provide insight into the bactericidal capacities of captured Florida Mottled Ducks. We statistically tested the BKA capacity, or microbial killing ability, of 23 Mottled Ducks in response to age and whole blood lead levels (Pb). We found that there was no statistically significant relationship between the covariates we measured and Mottled Duck BKA capacity against E. coli. However, the variability we observed in the BKA capacity of this subspecies warrants further research into additional physiological and ecological covariates coupled with potential immune stressors that Florida Mottled Ducks may be contending with.

Molecular identification of novel duck associated Chapparvovirus in ducks, first report from China

Molecular identification of novel duck associated Chapparvovirus in ducks, first report from China

Evaluating variation in acute stress response in captive Wood Ducks (Aix sponsa).

Evaluating variation in acute stress response in captive Wood Ducks (Aix sponsa).

Water Quality and Its Influence on Waterbird Habitat Distribution: A Study Along the Lieve River, Belgium

Freshwater ecosystems face increasing pressures from human activities, leading to degraded water quality and altered habitats for aquatic species. This study investigates the relationship between water quality and waterbird distribution along the Lieve River, Belgium, based on manually conducted waterbird counts and water quality data collected from 48 transects in March 2024. Localized eutrophication was evident, with TN (2.7–5.6 mg L−1), TP (up to 0.46 mg L−1), and chlorophyll-a (median 70 ppb) exceeding environmental thresholds. Prati index analysis revealed that 58.3% of the sampling points along the Lieve River were categorized as “polluted”, reflecting extensive water quality degradation. Eurasian coots (71.4%) and wild ducks (72.4%) were predominantly found in polluted areas, thriving in nutrient-enriched habitats linked to high TP levels. In contrast, common moorhens (80.3%) preferred acceptable quality areas, indicating higher water quality requirements. These findings indicate that phosphate is a key driver of waterbody eutrophication, as evidenced by the TP concentrations measured on-site, which far exceed the thresholds set by environmental standards. Future research should explore advanced monitoring approaches to improve waterbird and water quality assessments, ensuring the conservation of the Lieve River as one of Europe’s oldest artificial canals, and the protection of its waterbird habitats.

A synopsis of game bird banding in New Zealand to year 2000

The organised banding in New Zealand of birds that are seasonally hunted as game commenced in 1947 when wild grey ducks (Anas superciliosa) and mallards (A. platyrhynchos) were captured in Manawatu. From 1950, California quail (Callipepla californica) were caught and banded in central Otago and near Taupo as field studies of other game birds by Department of Internal Affairs Wildlife Branch staff commenced. At the same time, captive-raised mallards and common pheasants (Phasianus colchicus) were banded at release by acclimatisation societies, pre-empting a later legal requirement for banding of all released captive-raised game birds. By year 2000, approximately 150,000 of five species of introduced upland game birds (Galliformes) had been banded in New Zealand, including chukar partridge (Alectoris chukar), grey partridge (Perdix perdix), and red-legged partridge (Alectoris rufa), the latter two species ultimately failing to acclimatise. From this total, 7,267 were reported shot. By year 2000, approximately 370,000 of six species of wetland game birds — black swan (Cygnus atratus), Canada goose (Branta canadensis), paradise shelduck (Tadorna variegata), Australasian shoveler (Spatula rhynchotis), grey duck, and mallard (and their hybrids) — had been banded. From this total, 62,566 were reported shot. Banding records, and details arising from the reported recoveries of banded birds, were initially administered by the Wildlife Branch, Department of Internal Affairs 1947–66, after which records were amalgamated with the nascent Ornithological Society of New Zealand’s bird ringing scheme for all other species, to form the New Zealand Bird Banding Scheme. Administered 1967–87 by the Wildlife Service, the scheme has been managed thereafter by the Department of Conservation. This narrative summarises the scales, locations, and durations of bandings of each game bird species, quantifies the recovery records for each, and reports on all published outcomes arising from the banding activities. Supplementary files provide recovery arrays (banding year by recovery year) for each of the wetland species to preserve historic records and encourage belated appraisal of much unprocessed band-recovery information.

Viral metagenomics in wild ducks reveals the presence of seadornaviruses in Siberia.

Seadornavirus is a genus of mosquito-borne viruses that includes Banna virus, which was first discovered in human patients with encephalitis and fever, as well as Kadipiro virus and Liao ning virus. In this study, we used metagenomics to investigate the diversity of viruses in wild ducks and detected both Banna virus and Kadipiro virus in wild birds in Siberia. These data suggest that seadornaviruses, which were previously only found in South East Asia, are also circulating in Northern Eurasia.

Reaction-advection-diffusion model of highly pathogenic avian influenza with behavior of migratory wild birds.

Wild birds are one of the main natural reservoirs for avian influenza viruses, and their migratory behavior significantly influences the transmission of avian influenza. To better describe the migratory behavior of wild birds, a system of reaction-advection-diffusion equations is developed to characterize the interactions among wild birds, poultry, and humans. By the next-generation operator, the basic reproduction number of the model is formulated. Then the threshold dynamic of the model is explored by some techniques including the theory of uniform persistence, internally chain transitive sets, and so on. Subsequently, the sensitivity analysis of parameters associated with the basic reproduction number is implemented. According to the temporal and spatial overlapping relationship between wild blue-winged ducks and poultry in North America, the effect of this relationship on the characteristic of spatial-temporal distribution of the viruses is well studied. Additionally, the risk of virus transmission from wild birds to poultry and humans is evaluated. The main results highlight that the basic reproduction number is more significantly affected by the parameters related to wild birds. Interestingly, the model output regarding the spatial distribution of poultry infections is consistent with the actual findings. Moreover, the risk of virus spillover from wild birds into poultry and humans varies with wild bird behavior and has a more substantial impact on poultry. Throughout this study, the critical risk points in the transmission process are identified, providing a theoretical basis for the prevention and control of avian influenza.

First detection and diversity of astroviruses in wild migratory birds of Sakhalin Island, North Pacific.

Researchers have identified Avastrovirus as a significant genus of bird viruses, linked to various avian diseases such as enteritis, growth retardation, nephritis and hepatitis. These infections can cause substantial economic losses in agrocultureand have a widespread impact on global food production. Although there have been numerous studies on these viruses, most of them-mainly focuses on poultry. Research on astroviruses in wild bird populations has revealed a wide genetic diversity of these viruses, yet our understanding of their biological and ecological characteristics remains limited. In this study, we for the first time detected avastrovirus in wild migratory birds of the families Anatidae and Columbidae from Sakhalin Island, North Pacific Ocean. Phylogenetic analysis revealed the presence of Avastrovirus 2 in wild doves and Avastrovirus 3 in wild ducks. These findings provide valuable insights into the circulation of astroviruses in wild bird populations of Sakhalin Island, which lies along the East Asian-Australasian Flyway.

Whole-genome resequencing reveals genetic differentiation and selection signatures among wild, local and commercial duck populations

ObjectiveThe purpose of this study was to systematically analyze the population genetic structure and genetic diversity among wild, local and commercial populations using whole-genome sequencing data from 416 individuals of 22 duck breeds in China and to further explore genetic pathways and candidate genes associated with importantly economic traits.MethodsWe performed principal component analysis, an unrooted neighbor-joining phylogenetic tree and ADMIXTURE to analyze the population structure. We compared the genetic diversity among wild, local and commercial populations using the effective population size, inbreeding coefficient, expected heterozygosity, observed heterozygosity, nucleotide diversity and regions of homozygosity. To detect selection signatures, we calculated the locus-specific branch length for local and commercial populations and calculated genetic differentiation coefficient and genetic diversity between egg and dual-purpose breeds.ResultsWild, local and commercial duck populations formed three distinct genetic groups. The commercial population presented the lowest genetic diversity, the highest levels of inbreeding and the smallest effective population size. ADMIXTURE analysis also demonstrated that ducks were clearly divided into these three populations at K = 3. Selection signals in the commercial population were associated with growth and muscle development pathways, such as the mTOR signaling pathway and ErbB signaling pathway, and two key genomic regions (Chr1: 70.25 to 74.00 Mb and Chr2: 97.10 to 99.76 Mb) containing important genes, such as LRP6, BORCS5, and EDN1, were identified. In contrast, selection signals in the local population were associated with immune-related pathways involving NCAM2 and MPHOSPH6. Furthermore, PTGS2 and PLA2G4A genes were positively selected in egg breeds, whereas KCNK16, KCNK5, and KCNK17 genes were in dual-purpose breeds.ConclusionBecause of artificial selection, wild, local and commercial populations presented obvious genetic differences. The selection signal analysis revealed that LRP6, BORCS5, and EDN1 are important for growth and muscle development; NCAM2 and MPHOSPH6 are for immune traits; and PTGS2 and PLA2G4A are for egg-related traits.

Transmission dynamics of highly pathogenic avian influenza virus at the wildlife-poultry-environmental interface: A case study

Transmission dynamics of highly pathogenic avian influenza virus at the wildlife-poultry-environmental interface: A case study

Surveillance for Avian Influenza in Wild Birds in the Lombardy Region (Italy) in the Period 2022–2024

Influenza A virus (AIV) circulation was investigated in the Lombardy region, during 2022–2024, in wild ducks (through hunting and sampling of faecal samples within natural parks) and wild birds found dead. Samples were analysed through real-time RT-PCRs for Influenza A virus, H5 and H7. Whole genome sequencing was performed on AIV-positive samples. Screening of 3497 hunted Anatidae revealed a total of 184 positive samples. Complete sequencing of 136 samples highlighted the presence of 21 different subtypes ranging from H1N1 to H12N5. The H5N1 HPAIV (high pathogenic AIV) subtype, clade 2.3.4.4b, was the most common during the 2022–2023 winter season (31.8%), while H5 LPAI (low pathogenic AIV) strains were the most prevalent (28.6%) in the 2023–2024 season. The molecular survey on wild birds found dead (n = 481) showed two positive buzzards (14%, 2/14), one grey heron (5.5%, 1/18) and one kestrel (7.6%, 1/13). Regarding the order of Charadriiformes, the dead gulls sampled in 2022 (17 birds) were all negative, whereas 85 out of 167 (51%) individuals were positive in 2023. All positives were caused by an H5N1 HPAIV clade 2.3.4.4b virus belonging to genotype BB. All the faecal samples (1699) received from passive surveillance in nature parks were analysed for AIV with negative results.

Transcriptional activity and variation analysis of genes critical for long-chain fatty acid (C≥16) elongation and desaturation in Pekin ducks

Transcriptional activity and variation analysis of genes critical for long-chain fatty acid (C≥16) elongation and desaturation in Pekin ducks

Molecular Screening and Characterization of Enteric Protozoan Parasites and Microsporidia in Wild Ducks from Portugal.

Enteric parasites pose significant threats to both human and veterinary health, ranking among the top causes of mortality worldwide. Wild migratory waterfowl, such as ducks, may serve as hosts and vectors for these parasites, facilitating their transmission across ecosystems. This study conducted a molecular screening of enteric parasites in three species of wild ducks of the genus Anas (A. acuta, A. platyrhynchos and A. crecca) from Portugal, targeting Blastocystis sp., Balantioides coli, Cryptosporidium spp., Encephalitozoon spp., and Enterocytozoon bieneusi. Fecal samples from 71 ducks were analyzed using PCR and sequencing techniques. The results revealed a 2.82% occurrence of Blastocystis sp. subtype 7 and Cryptosporidium baileyi, marking the first molecular detection of these pathogens in wild ducks in Portugal. While previous studies have documented these parasites in Anas spp. in other regions, this study contributes novel data specific to the Portuguese context. No evidence of Balantioides coli, Encephalitozoon spp. or Enterocytozoon bieneusi was found. These findings highlight the potential role of migratory ducks as vectors for zoonotic protozoa, emphasizing the need for enhanced surveillance of avian populations to mitigate cross-species transmission risks. Further research is warranted to understand the global public health implications associated with migratory waterfowl.

Outbreaks of highly pathogenic avian influenza (HPAI) epidemics in Baltic Great Cormorant Phalacrocorax carbo colonies in 2021 and 2022

ABSTRACT Capsule Over 1,700 Great Cormorants died from H5N1 highly pathogenic avian influenza (HPAI) at 11 breeding colonies in the Baltic Sea region, and one in the North Sea, in summer 2021 and 2022. Aim To determine the nature and impacts of the 2021/2022 HPAI outbreaks on Great Cormorants in the Baltic Sea region. Methods We collected data on HPAI outbreaks in Baltic Great Cormorant colonies through questionnaires, national virological and serological surveys, and avian influenza surveillance databases to better understand the 2021/2022 outbreak. Results The HPAI H5 clade 2.3.4.4b (goose/Guangdong lineage) caused mortality in five Great Cormorant breeding colonies in Denmark, three in Germany, two in Sweden and single outbreaks in Estonia and Latvia (all ground-nesting colonies). HPAI H5 monitoring of Great Cormorants in Germany since 2006 showed an increasing prevalence from 2022. Great Cormorant H5N1 viruses belonged to a genotype circulating in wild ducks since 2021. After 2021/2022 morbidity and no subsequent outbreaks, breeding colony sizes returned to above-normal levels in 2023. Conclusion After H5N1 HPAI outbreaks in 11 exclusively ground-nesting colonies of Great Cormorants in the Baltic Sea (and one in the North Sea) in 2022, breeding numbers recovered in 2023. Lack of subsequent mortality suggested immunity, but serological investigations are needed to determine the prevalence of protective antibodies in this and other coastal birds.