Spot-billed Duck Research Articles

Genetic Characterization and Pathogenesis of Avian Influenza Virus H7N3 Isolated from Spot-Billed Ducks in South Korea, Early 2019.

Low-pathogenicity avian influenza viruses (LPAIV) introduced by migratory birds circulate in wild birds and can be transmitted to poultry. These viruses can mutate to become highly pathogenic avian influenza viruses causing severe disease and death in poultry. In March 2019, an H7N3 avian influenza virus—A/Spot-billed duck/South Korea/WKU2019-1/2019 (H7N3)—was isolated from spot-billed ducks in South Korea. This study aimed to evaluate the phylogenetic and mutational analysis of this isolate. Molecular analysis revealed that the genes for HA (hemagglutinin) and NA (neuraminidase) of this strain belonged to the Central Asian lineage, whereas genes for other internal proteins such as polymerase basic protein 1 (PB1), PB2, nucleoprotein, polymerase acidic protein, matrix protein, and non-structural protein belonged to that of the Korean lineage. In addition, a monobasic amino acid (PQIEPR/GLF) at the HA cleavage site, and the non-deletion of the stalk region in the NA gene indicated that this isolate was a typical LPAIV. Nucleotide sequence similarity analysis of HA revealed that the highest homology (99.51%) of this isolate is to that of A/common teal/Shanghai/CM1216/2017 (H7N7), and amino acid sequence of NA (99.48%) was closely related to that of A/teal/Egypt/MB-D-487OP/2016 (H7N3). An in vitro propagation of the A/Spot-billed duck/South Korea/WKU2019-1/2019 (H7N3) virus showed highest (7.38 Log10 TCID50/mL) virus titer at 60 h post-infection, and in experimental mouse lungs, the virus was detected at six days’ post-infection. Our study characterizes genetic mutations, as well as pathogenesis in both in vitro and in vivo model of a new Korea H7N3 viruses in 2019, carrying multiple potential mutations to become highly pathogenic and develop an ability to infect humans; thus, emphasizing the need for routine surveillance of avian influenza viruses in wild birds.

Modelling growth curve of Eastern spot-billed ducks (<i>Anas zonorhyncha</i>) raised in Vietnam

Modelling growth curve of Eastern spot-billed ducks (<i>Anas zonorhyncha</i>) raised in Vietnam

Revisiting the evolutionary history of domestic and wild ducks based on genomic analyses.

Although domestic ducks have been important poultry species throughout human history, their origin remains enigmatic, with mallards and/or Chinese spot-billed ducks being proposed as the direct wild ancestor(s) of domestic ducks. Here, we analyzed 118 whole genomes from mallard, Chinese spot-billed, and domestic ducks to reconstruct their evolutionary history. We found pervasive introgression patterns among these duck populations. Furthermore, we showed that domestic ducks separated from mallard and Chinese spot-billed ducks nearly 38 thousand years ago (kya) and 54 kya, respectively, which is considerably outside the time period of presumed duck domestication. Thus, our results suggest that domestic ducks may have originated from another wild duck population that is currently undefined or unsampled, rather than from present-day mallard and/or Chinese spot-billed ducks, as previously thought. Overall, this study provides new insight into the complex evolution of ducks.

Genetic signature of hybridization between Chinese spot-billed ducks and domesticated ducks.

In this study, we analyzed 93 whole genomes from Chinese spot-billed ducks (CSB), meat-type ducks (MET), and egg and dual purpose-type ducks (EDT) to characterize the genetic material flowing between the CSB and modern ducks. Using a frequency of shared identical-by-descent method, approximately 10.9Mb introgression segments containing 140 genes were identified showing the signatures of introgression between CSB and EDT. Meanwhile, nearly 10.6M introgression regions containing 149 genes were identified between CSB and MET. Based on the haplotypes tree of each segment, we found that the introgression between CSB and domesticatedducks was asymmetric with a high level of gene flow from domestic to CSB and a low level of migration in the opposite direction. Moreover, we identified several genes that were introgressions from CSB and showed the signature of positive selection, which may contribute to the breeding of modern ducks. Our results provide new insight into the evolution and breeding history of domestic ducks and may be useful for the future management of wild and domestic duck populations.

Prevalence and potential risk of Salmonella enterica in migratory birds from South Korea

Salmonella is a type of zoonotic bacteria that represents an economic and public health concern worldwide. Difficulties in sample collection from migratory birds mean little is known about their importance as a reservoir of Salmonella. The present study evaluated the prevalence and potential risk of Salmonella enterica in migratory birds. From 2012–2017, 3661 cloacal swabs from migratory birds were collected in South Korea and tested to isolate S. enterica. Strains were tested for antimicrobial resistance and the presence of virulence genes. Thirty-six S. enterica strains, including S. enterica serovar Typhimurium (n = 19), S. Berta (n = 16), and S. Virchow (n = 1), were isolated from 34 birds. Two migratory birds were simultaneously co-infected with two serotypes. S. enterica was isolated from the Mallard duck, Northern pintail, Eurasian wigeon, Spot-billed duck, Eastern great egret, and Intermediate egret. S. Virchow was resistant to ciprofloxacin, with a point mutation (Ser-83-Phe) in the gyrA gene. Ten virulence genes were detected; sixteen strains were positive for all ten virulence genes. Salmonella was isolated from different migratory bird species and geographic locations with up to 100 % similarity of PFGE type. Eight S. Virchow strains taken from migratory birds, poultry farms, and chicken meat showed the same PFGE type. Salmonella was transmitted across species, space, and time in migratory birds. These birds may play a role in the dispersal of pathogenic and antimicrobial-resistant Salmonella and sporadic Salmonella infections in poultry; therefore, they may represent a direct or indirect public health threat.

Diversity of wintering waterbirds enhanced by restoring aquatic vegetation at Shengjin Lake, China

The restoration of planted vegetation contributes towards improving the habitat quality of waterbirds and enhancing the diversity of their communities. Thus, the success of projects attempting to restore aquatic vegetation could, in part, be quantified by evaluating the community structure of wintering waterbirds. Here, we evaluated the effect of wetland restoration (through planting aquatic vegetation) by comparing waterbird communities in restored versus unrestored areas over two wintering periods (2017–2018 and 2018–2019). Specifically, the use of aquatic vegetation by waterbirds was evaluated following restoration, and was compared against three control (unrestored) areas; namely, a Euryale ferox planting area, freshwater aquaculture area, and rice planting area. Twenty-nine species belonging to eleven families of waterbirds were recorded across the four habitats. Species richness and density of waterbirds in the restored aquatic vegetation area were significantly higher than those in the three control areas. The restored aquatic vegetation area had the highest absolute value of Temporal Beta-diversity Index (TBI), while species gains (C) were significantly greater than species losses (B). Additionally, there was a significant increase in the number of wintering waterbird species from three foraging guilds in the restored aquatic vegetation area during the wintering period of 2018–2019 compared to 2017–2018 (Granivore guild; Invertivore guild; Piscivore guild). The restoration of aquatic vegetation mainly caused the number of Anatidae species to increase, including ruddy shelduck (Tadorna ferruginea), common teal (Anas crecca), common mallard (Anas platyrhynchos), spot-billed duck (Anas poecilorhyncha), and common pochard (Aythya ferina). Submerged vegetation provides ducks with important food resources, such as seeds. And emerging vegetation facilitating the concealment of waterbirds. In conclusion, the artificial promotion of aquatic vegetation restoration at Shengjin Lake has contributed towards maintaining the structure of wintering waterbird communities.

생태하천으로 조성된 반석천의 물새류 출현특성

This study was conducted as a basic research to create a sound and vital ecological environment in the city compared to the appearance characteristics of Gap stream(G-stream), which are the main stream of Banseok stream(B-stream), by analyzing the characteristics of waterbirds, including Wild Spot-billed Duck (S-Duck), that live in B-stream built as ecological stream. The waterbird survey was conducted by the line census for 3.2km, Jukdong-bridge to Jamiseon-bridge, from January to August 2018. The analysis of the survey was conducted with Relative species density(RD) of the emerging waterbird species, the Species diversity and Density Per Unit area for 100m²(DPU). The waterbird survey results of B-stream was conducted 65 times. The five types of water birds that appeared during the survey were Spot-billed Duck(Anas poecilorhyncha), Teal(Anas crecca), Little Egret(Egretta garzetta), Great Egret(Egretta alba), and Grey Heron(Ardea cinerea). As a result, for S-Duck at B-stream, RD was 89.9%, monthly species diversity was simple as 0.3801 in January, 0.5943 in February and 0.3501 in August. The DPU of the S-Duck was 0.165/100m² in the B-Stream survey section which was 4.9 times higher than the main stream section, G-stream. The non-freezing zone of the city’s small stream is expected to play an important role as a winter stop for wild birds such as S-Duck during the freezing period of the huge stream. For this reason, considering the ecological characteristics of wild waterbirds such as S-Duck when creating ecological stream, a: space and linear selection of waterways which can minimize the impact of natural enemy and increasing the number of walkers, b: management water-friendly plants in the low flow channel, c: arrangement walking-bicycle road will be necessary.

Diversity and Abundance of Waterbird Communities in the Jaffna and Kilinochchi Districts: Where do we have to go from here?

Wetlands and waterbirds are inseparable elements. The preliminary study was conducted in eight sites, namely Mandaitivu, Mankumban, Kayts, Kavutharimunai, Pallai, Thadduvankoddy, Kapputhu and Nagarkovil in the Jaffna and Kilinochchi Districts of the northern region of Sri Lanka to determine the diversity and abundance of waterbirds. In each site, three counting blocks in length of 500 m with open width was selected for bird counting. Each block was separated at least by length of 500 m to avoid double counting. The counting of birds was done once a month from December, 2016 to May, 2017. Eighteen waterbird families were recorded. Phoenicopteridae, Anatidae and Scolopacidae were the dominant families. The presence of critically endangered species such as Spot-billed Duck (Anas poecilorhyncha) suggests the importance of conservation of these habitats. Two-way ANOVA indicated that waterbird families were significantly different among eight sites. The highest species richness was found in Kapputhu (57) and the lowest in Kavutharimunai (26). This study revealed that Mandaitivu, Mankumban, Kayts, Thadduvankoddy and Kapputhu are the excellent places to observe both migrant ducks and flamingos. Likewise Kavutharimunai is good for migrant shorebirds and seabirds by ferry while Nagarkovil and Kapputhu are suitable for viewing both feeding and roosting of waterbirds. On the whole this paper reveals that the northern region of Sri Lanka possess not only the potential of avitourism but also will become the hotspot of future bird researches, especially on waterbirds.

GPS-TX による越冬期のマガモ，カルガモの行動追跡

GPS-TX による越冬期のマガモ，カルガモの行動追跡

Angel Wing in a Young Captive-Reared Spot-Billed Duck (Anas poecilorhyncha)

Angel Wing in a Young Captive-Reared Spot-Billed Duck (Anas poecilorhyncha)

Migratory flyways in Far-East Asia and spatial-temporal relationship to HPAI H5N6 outbreaks in South Korea

Event Abstract Back to Event Migratory flyways in Far-East Asia and spatial-temporal relationship to HPAI H5N6 outbreaks in South Korea Seong-Keun Hong1*, Kwang-Nyeong Lee1, Hachung Yoon1, Dae-Sung Yoo1, Ilseob Lee1 and Han-Mo Son1 1 Animal and Plant Quarantine Agency (South Korea), Republic of Korea Since 2016, 365 cases of highly pathogenic avian influenza virus (HPAIv) outbreaks by the Asian-origin H5N6 lineage of HPAIv have reported in South Korea and resulted in serious socio-economical losses. In this study, we demonstrated that the risk of HPAIv H5N6 in domestic poultry is related to wild birds. We expanded previous geospatial risk analysis method to East Asia including South Korea and integrated the analysis method with migration data of satellite-tracked wild birds along the far-east Asian flyway. We caught wild migratory birds around Lake Khanka (southeast area) collaborate with Russian researchers and attached a location tracker. From April to November 2018, we studied movement of 21 wild birds which carrying location tracker: 4 mallards, 2 spot-billed ducks, and 15 great egrets. The great egrets showed highest tracking success rate. During the migration, they stopped at several stopover sites (Russia to Japan; 1 mallard, 1 spot-billed duck, 1 great egret), and stayed for several weeks at those sites. We also demonstrated that migratory pathway of wild birds is correlated with HPAI H5N6 outbreaks, poultry density and latitude in East Asian Flyways. Spatial and statistical analysis was performed in ArcGIS 10.4.1(ESRI) and R 3.5.3. In addition, satellite-based movement patterns of wild birds showed that wild birds followed the East Asian flyway along the coast to breeding areas in eastern Russia. Taken together, our results suggest that it is important to analyze the tracking records of the movement of wild birds in various ways for making inference on the relationship between the migration of wild birds and outbreaks of HPAIv. Acknowledgements For field assistance with wild bird studies, we acknowledge the corperation of dedicated staff at Russian institutions, including Igor Katin and Ivan Tinuov(NSCMB FEB RAS). Additional support for tracking system was also provided by Korea Ecology Environment Research Institute, South Korea, including Han-Soo Lee. Any use of product or firm names is for descriptive purposes and does not imply endorsement by the South Korea Government.

Identification of highly pathogenic avian influenza suitable areas for wild birds using species distribution models in South Korea.

Event Abstract Back to Event Identification of highly pathogenic avian influenza suitable areas for wild birds using species distribution models in South Korea. Lee Kyuyoung1*, Dae-sung Yu2*, Beatriz Martínez-López1, Jaber A. Belkhiria1, Sung-il Kang2, Hachung Yoon2, Seong-Keun Hong2, ILSEOB LEE2, Han-Mo Son2 and Kwangnyeong Lee2 1 Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, United States 2 Animal and Plant Quarantine Agency (South Korea), Republic of Korea Highly pathogenic avian influenza (HPAI) virus is influenza A type virus with high mortality and morbidity in the broad range of host species domestic and wild birds to humans. HPAI infection has been a high-priority concern in global poultry industry because of consistent generation and circulation of novel HPAI strains, and consequent tremendous financial losses. Wild birds are considered one of the most important sources of novel HPAI introductions in poultry farms due to the experimental evidence of their asymptomatic infection with viral shedding, genetic closeness of HPAI virus identified in domestic poultry and wild birds, and spatial and temporal coincidence of identification of HPAI in wild birds and domestic poultry. The poultry industry in South Korea has annually suffered from the introduction of novel HPAI strains since early 2000s. HPAI infection in annually migrated wild birds has been carefully monitored to rapidly establish preventive measures of HPAI introduction into poultry farms in South Korea. However, current understanding of highly risk areas or suitable areas for HPAI in wild birds and contribution of other geographical and environmental factors contributing to HPAI vírus suitability is limited. Application of species distribution models based on digitalized geographical and environmental information facilitates our understanding about suitability of wild species’ habitat and its association with environmental and geographical factors. Furthermore, species distribution modelling can be applied to identify high-risk areas of potential disease transmission at the interface between wild species and domestic animals. Our study aimed to evaluate the areas with higher suitability/risk for HPAI identification in wild birds in South Korea and to describe what is the influence or association with the different environmental and geographical factors. Our results will help to not only have a better understanding of the ecology of HPAI in wild birds but also to establish more effective, risk-based, surveillance to prevent novel HPAI introductions into domestic poultry farms in South Korea We obtained land cover, monthly climate (precipitation, temperature and wind speed) and ecological preservation area (Level 1-3) data of South Korea in digitalized form as environmental and geographical data. The observation records of 7 species of wild birds (Baikal teal, white-front goose, common teal, mandarin duck, mallard, bean goose, spot-billed duck) in 206 habitats in South Korea from 1999 to 2017 were used to estimate the suitability map for the wild bird distribution in South Korea. The geographical records of wild bird HPAI surveillance from 2014 to 2018 was combined with 7 wild birds species distribution and environmental and geographical data to estimate the suitability map of HPAI identification in wild birds. Each suitability maps was estimated by maximum entropy approach (Maxent model) via the “dismo” package in R studio. 3. Results and Discussion Our study presents the suitability map of HPAI identification in wild birds and how geographical, environmental factors and 7 wild birds species distributions are contributing to the prediction. These results will not only provide a high-resolution map for the target allocation of surveillance and rapid detection of HPAI in wild birds but also will allow the improvement of the cost-effectiveness of risk-based surveillance of HPAI introduction into domestic poultry farms in South Korea. Acknowledgements This study was supported by the 2019-20 cooperative research grant from the veterinary epidemiology Division in the Animal and Plant Quarantine Agency (APQA) in South Korea and the fellowship of the graduate student support program (GSSP) at UC Davis

간척지의 환경변화가 흰뺨검둥오리 서식에 미치는 영향

간척지의 환경변화가 흰뺨검둥오리 서식에 미치는 영향

Monitoring 137Cs concentrations in bird species occupying different ecological niches; game birds and raptors in Fukushima Prefecture

This study was conducted to assess radiocesium accumulation in birds after the accident at Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station in 2011, with a particular focus on 137Cs, which has a long physical half-life. Results of 137Cs monitoring in four game bird species including two pheasant species and two duck species (copper pheasant, green pheasant, spot-billed duck and mallard) were assessed in Fukushima Prefecture. We also obtained samples from rescued raptors that died during treatment or rehabilitation at the Wildlife Symbiosis Centre in Fukushima Prefecture because of severe injury. We measured the muscle concentrations of 137Cs in four of these raptor species (black kite, northern goshawk, peregrine falcon and ural owl). Comparison of the two pheasant species showed that the copper pheasants inhabiting forested areas had higher 137Cs concentrations in muscle (Bq/kg, fresh mass) than the green pheasants inhabiting mountainous areas near human habitation (i.e., Satoyama). No clear tendencies were observed in 137Cs concentration in muscle of copper pheasants over time, but a tendency to decrease was observed in green pheasants over time. The difference in tendencies between species may be attributable to differences in their food habits and its 137Cs concentration, and also differences in the situation of 137Cs accumulation in their habitat. No significant differences were observed in 137Cs concentration in muscle between the resident spot-billed duck and migratory mallard because of the comparatively short biological of effective half-life of radiocesium. Analysis of 137Cs concentration in muscle of raptor revealed that the concentration was similar to, or lower than, those of pheasants and ducks.

Incomplete lineage sorting and introgression in the diversification of Chinese spot-billed ducks and mallards.

Incomplete lineage sorting and introgression are 2 major and nonexclusive causes of species-level non-monophyly. Distinguishing between these 2 processes is notoriously difficult because they can generate similar genetic signatures. Previous studies have suggested that 2 closely related duck species, the Chinese spot-billed duck Anas zonorhyncha and the mallard A. platyrhynchos were polyphyletically intermixed. Here, we utilized a wide geographical sampling, multilocus data and a coalescent-based model to revisit this system. Our study confirms the finding that Chinese spot-billed ducks and Mallards are not monophyletic. There was no apparent interspecific differentiation across loci except those at the mitochondrial DNA (mtDNA) control region and the Z chromosome (CHD1Z). Based on an isolation-with-migration model and the geographical distribution of lineages, we suggest that both introgression and incomplete lineage sorting might contribute to the observed non-monophyly of the 2 closely related duck species. The mtDNA introgression was asymmetric, with high gene flow from Chinese spot-billed ducks to Mallards and negligible gene flow in the opposite direction. Given that the 2 duck species are phenotypically distinctive but weakly genetically differentiated, future work based on genome-scale data is necessary to uncover genomic regions that are involved in divergence, and this work may provide further insights into the evolutionary histories of the 2 species and other waterfowls.

Genetic characterization of low-pathogenic avian influenza viruses isolated on the Izumi plain in Japan: possible association of dynamic movements of wild birds with AIV evolution.

The Izumi plain in Kagoshima Prefecture, Japan, is an overwintering site of endangered cranes (hooded cranes and white-naped cranes) and of many other migratory birds (including wild ducks) that are considered carriers of avian influenza viruses (AIVs). To assess the risks of a highly pathogenic avian influenza outbreak in the crane populations, we tested various environmental samples for AIVs in this area. In the 2014-2015 winter season, we isolated one AIV of the H6N2 subtype from the cranes' roost water and two AIVs of the H11N9 subtype from a crane fecal sample and a cloacal swab of a dead spot-billed duck. Genetic analysis of these AIV isolates indicated that our H6N2 isolate is genetically close to AIVs isolated from wild birds in Southeast Asian countries, except that the PB1 and NS genes belong to the North American virus lineage. All genes of the two H11N9 isolates are related to AIVs belonging to the Eurasian virus lineage. Notably, in our phylogenetic trees, H11 HA and N9 NA genes showing high sequence similarity to the corresponding genes of isolates from wild birds in South Africa and Spain, respectively, did not cluster in the major groups with recent wild-bird isolates from East Asia. These results suggest that AIVs with viral gene segments derived from various locations and bird species have been brought to the Izumi plain. These findings imply a possible association of dynamic movements of wild birds with AIV evolution.

Distribution and Long-Term Population Trends of Wintering Waterbirds in Poyang Lake, China

Although total wintering waterbirds have increased in Poyang Lake, some groups or species might have declined. Identifying declining groups and species will help to optimize conservation strategies. In addition, knowledge of waterbird distribution is required to identify priority areas for protection. In this study, we aimed to explore long-term population trends of waterbird groups and species and to investigate waterbird distribution in Poyang Lake by integrating survey data from 1996/1997 to 2014/2015. Poyang Lake Nature Reserve, Duchang and Nanji Wetland Nature Reserve had high waterbird richness and abundance and high proportion of IUCN endangered species, thus they are important areas for waterbird protection. An important limitation to waterbird protection in the three areas is lack of management rights of most sub-lakes. Most waterbird groups in Poyang Lake have grown, but ducks have declined. Hunting and the decline of aquatic vegetation might be driving the duck declines. In addition, White-naped Crane (Grus vipio), Spot-billed Duck (Anas poecilorhyncha) and Northern Lapwing (Vanellus vanellus) have declined. While we believe the data presented here indicate general trends in groups and species, the analyses suffered from variation in methods used in different surveys. We advocate long-term waterbird monitoring using standardized methods to better understand waterbirds’ population dynamics.

Diversity and Conservation of Waterbirds in the Northern Avifaunal Region of Sri Lanka

The aim of the present study is to evaluate the waterbird diversity, distribution, and conservation status in the northern avifaunal region of Sri Lanka, which includes two of the four richest waterbird regions in Sri Lanka, namely Jaffna and Mannar. We compiled data from the annual waterbird censuses and monthly records of the Ceylon Bird Club from 2011 to 2017 and from a systematic survey carried out by us from October 2014 to March 2016. We recorded a total of 116 species of waterbirds belonging to 23 families. Among them are species confined to the northern region including the rare breeding residents the Crab Plover ( Dromas ardeola ), Indian Courser ( Cursorius coromandelicus ), Spot-billed Duck ( Anas poecilorhyncha ), and Saunders’s Tern ( Sternula saundersi ). The Greater Flamingo ( Phoenicopterus roseus ), which is now uncommon elsewhere in Sri Lanka, was recorded in high numbers. The Spot-billed Duck, which was a very rare migrant to Sri Lanka until recently, was found to have established breeding populations in the region. The Glossy Ibis ( Plegadis falcinellus ) and Comb Duck ( Sarkidiornis melanotos ), which are extirpated breeding residents in Sri Lanka, were recorded as part of the migrant population. The Common Coot ( Fulica atra ), which was previously considered a very rare breeding resident, was found to be abundant with over 1,000 individuals in some localities.

A Novel Avian Paramyxovirus (Putative Serotype 15) Isolated from Wild Birds.

In January 2014, a viral hemagglutinating agent named UPO216 was isolated from fecal droppings of wild birds at the UPO wetland in South Korea during an avian influenza surveillance program. Electron microscopy identified the UPO216 virus as an avian paramyxovirus (APMV). Pathogenicity tests and molecular pathotyping revealed that the virus was avirulent in chickens. The UPO216 virus was assigned to a serological group antigenically distinct from known serotypes of APMV (−1, −2, −3, −4, −6, −7, −8, and −9) by hemagglutination inhibition test, despite showing weak cross-reactivity with APMV-1 and APMV-9. The UPO216 virus RNA genome is 15,180 nucleotides (nts) in length, encodes 3′-N-P(V/W)-M-F-HN-L-5′ in that order, and shows unique genetic characteristics in terms of genomic composition and evolutionary divergence (0.43 or greater from known serotypes of APMV). Phylogenetic analysis revealed that the UPO216 occupies a branch separate from APMV-1, -9, -12, and -13. Serologic surveillance of wild birds (n = 880; 15 species, five Orders) detected UPO216-reactive antibodies in 4% (20/494) of serum samples taken from five species of wild duck belonging to the Order Anseriformes. In particular, UPO216-specific antibodies showing no cross-reaction with other serotypes of APMV were detected in four species: Eurasian teal (1/36), European wigeon (1/73), mallard (4/139), and Spot-Billed duck (1/137). These results indicate that the UPO216 virus has antigenically and genetically unique characteristics distinct from known serotypes of APMV and likely has been circulating widely in wild duck species of the Order Anseriformes. Thus, we propose the UPO216 isolate as a prototype strain of a novel APMV serotype (putative APMV-15).

Characterizing the temporal patterns of avian influenza virus introduction into Japan by migratory birds.

The objectives of the present study were to observe the temporal pattern of avian influenza virus (AIV) introduction into Japan and to determine which migratory birds play an important role in introducing AIV. In total, 19,407 fecal samples from migratory birds were collected at 52 sites between October 2008 and May 2015. Total nucleic acids extracted from the fecal samples were subjected to reverse transcription loop–mediated isothermal amplification to detect viral RNA. Species identification of host migratory birds was conducted by DNA barcoding for positive fecal samples. The total number of positive samples was 352 (prevalence, 1.8%). The highest prevalence was observed in autumn migration, and a decrease in prevalence was observed. During autumn migration, central to southern Japan showed a prevalence higher than the overall prevalence. Thus, the main AIV entry routes may involve crossing the Sea of Japan and entry through the Korean Peninsula. Species identification was successful in 221 of the 352 positive samples. Two major species sequences were identified: the Mallard/Eastern Spot-billed duck group (115 samples; 52.0%) and the Northern pintail (61 samples; 27.6%). To gain a better understanding of the ecology of AIV in Japan and the introduction pattern of highly pathogenic avian influenza viruses, information regarding AIV prevalence by species, the prevalence of hatch-year migratory birds, migration patterns and viral subtypes in fecal samples using egg inoculation and molecular-based methods in combination is required.