Surveillance of avian influenza viruses from 2014 to 2018 in South Korea.

Surveillance of influenza A viruses (IAVs) among migratory waterfowl is a first step in understanding the ecology, biology, and pathogenicity of IAVs. As part of the nationwide surveillance effort for IAVs in fowl in South Korea, we collected environmental fecal samples in different migratory bird stopover sites in South Korea during the winter seasons within November 2014 through January 2018. We collected a total of 6758 fecal samples, 75 of which were positive for IAV (1.11% positivity). Prevalence of IAVs varied per site and per year. Based on sequencing, the most prevalent hemagglutinin (HA) subtypes were H1, H6, and H5, and the most prevalent neuraminidase (NA) subtypes were N1, N3, and N2. Phylogenetic analyses showed that the genes we isolated clustered with reported isolates collected from other locations along the East Asian-Australasian Flyway. All the H5 and H7 isolates collected in this study were of low pathogenicity. None of the N1 and N2 genes carried amino acid markers of resistance against NA inhibitors. The winter 2016-2017 subset were primarily borne by migratory geese (Anser spp.). These results suggest that majority of the IAVs circulating among migratory wild fowl in South Korea in 2014-2018 were of low pathogenicity.

Emergence, prevalence, and evolution of H5N8 avian influenza viruses in central China, 2020.

Highly pathogenic influenza A(H5N8) viruses have caused several worldwide outbreaks in birds and are able cross the species barrier to infect humans, posing a substantial threat to public health. After the first detection of H5N8 viruses in deceased swans in Inner Mongolia, we performed early warning and active monitoring along swan migration routes in central China. We isolated and sequenced 42 avian influenza viruses, including 40 H5N8 viruses, 1 H5N2 virus, and 1 H9N2 virus, in central China. Our H5N8 viruses isolated in swan stopover sites and wintering grounds showed high nucleotide homologies in the whole genome, revealing a common evolutionary source. Phylogenetic analysis revealed that the H5 viruses of clade 2.3.4.4b prevalent in 2020 have further diverged into two sub-clades: b1 and b2. The phylogeographic analysis also showed that the viruses of sub-clade b2 most likely originated from poultry in Russia. Notably, whooper swans were found to be responsible for the introduction of sub-clade b2 viruses in central China; whooper and tundra swans play a role in viral spread in the Yellow River Basin and the Yangtze River Basin, respectively. Our findings highlight swans as an indicator species for transborder spreading and monitoring of the H5N8 virus.

Diversity of Coronaviruses in Wild Representatives of the Aves Class in Poland.

The revealed prevalence of coronaviruses in wild bird populations in Poland was 4.15% and the main reservoirs were birds from orders Anseriformes and Charadriiformes, with a prevalence of 3.51% and 5.59%, respectively. Gammacoronaviruses were detected more often than deltacoronaviruses, with detection rates of 3.5% and 0.7%, respectively. Gammacoronaviruses were detected in birds belonging to six orders, including Anseriformes, Charadriiformes, Columbiformes, Galliformes, Gruiformes, and Passeriformes, indicating a relatively wide host range. Interestingly, this was the only coronavirus detected in Anseriformes (3.51%), while in Charadriiformes, the prevalence was 3.1%. The identified gammacoronaviruses belonged to the Igacovirus and Brangacovirus subgeneras. Most of these were igacoviruses and formed a common phylogenetic group with a Duck Coronavirus 2714 and two with an Avian Coronavirus/Avian Coronavirus9203, while the viruses from the pigeons formed a distinct "pigeon-like" group, not yet officially represented. The presence of deltacoronaviruses was detected in birds belonging to three orders, Charadriiformes, Galliformes, and Suliformes indicating a narrower host range. Most identified deltacoronaviruses belonged to the Buldecovirus subgenus, while only one belonged to Herdecovirus. Interestingly, the majority of buldecoviruses were identified in gulls, and they formed a distinct phylogenetic lineage not represented by any officially ratified virus species. Another separate group of buldecoviruses, also not represented by the official species, was formed by a virus identified in a common snipe. Only one identified buldecovirus (from common pheasant) formed a group with the ratified species Coronavirus HKU15. The results obtained indicate the high diversity of detected coronaviruses, and thus also the need to update their taxonomy (establishing new representative virus species). The serological studies performed revealed antibodies against an infectious bronchitis virus in the sera of white storks and mallards.

A SYSTEMATIC REVIEW AND NARRATIVE SYNTHESIS OF THE USE OF ENVIRONMENTAL SAMPLES FOR THE SURVEILLANCE OF AVIAN INFLUENZA VIRUSES IN WILD WATERBIRDS.

Wild waterbirds are reservoir hosts for avian influenza viruses (AIV), which can cause devastating outbreaks in multiple species, making them a focus for surveillance efforts. Traditional AIV surveillance involves direct sampling of live or dead birds, but environmental substrates present an alternative sample for surveillance. Environmental sampling analyzes AIV excreted by waterbirds into the environment and complements direct bird sampling by minimizing financial, logistic, permitting, and spatial-temporal constraints associated with traditional surveillance. Our objectives were to synthesize the literature on environmental AIV surveillance, to compare and contrast the different sample types, and to identify key themes and recommendations to aid in the implementation of AIV surveillance using environmental samples. The four main environmental substrates for AIV surveillance are feces, feathers, water, and sediment or soil. Feces were the most common environmental substrate collected. The laboratory analysis of water and sediment provided challenges, such as low AIV concentration, heterogenous AIV distribution, or presence of PCR inhibitors. There are a number of abiotic and biotic environmental factors, including temperature, pH, salinity, or presence of filter feeders, that can influence the presence and persistence of AIV in environmental substrates; however, the nature of this influence is poorly understood in field settings, and field data from southern, coastal, and tropical ecosystems are underrepresented. Similarly, there are few studies comparing the performance of environmental samples to each other and to samples collected in wild waterbirds, and environmental surveillance workflows have yet to be validated or optimized. Environmental samples, particularly when used in combination with new technology such as environmental DNA and next generation sequencing, provided information on trends in AIV detection rates and circulating subtypes that complemented traditional, direct waterbird sampling. The use of environmental samples for AIV surveillance also shows significant promise for programs whose goal is early warning of high-risk subtypes.

Comparative pathogenicity and environmental transmission of recent highly pathogenic avian influenza H5 viruses.

Strategies to control spread of highly pathogenic avian influenza (HPAI) viruses by wild birds appear limited, hence timely characterization of novel viruses is important to mitigate the risk for the poultry sector and human health. In this study we characterize three recent H5-clade 2.3.4.4 viruses, the H5N8-2014 group A virus and the H5N8-2016 and H5N6-2017 group B viruses. The pathogenicity of the three viruses for chickens, Pekin ducks and Eurasian wigeons was compared. The three viruses were highly pathogenic for chickens, but the two H5N8 viruses caused no to mild clinical symptoms in both duck species. The highest pathogenicity for duck species was observed for the most recent H5N6-2017 virus. For both duck species, virus shedding from the cloaca was higher after infection with group B viruses compared to the H5N8-2014 group A virus. Higher cloacal virus shedding of wild ducks may increase transmission between wild birds and poultry. Environmental transmission of H5N8-2016 virus to chickens was studied, which showed that chickens are efficiently infected by (fecal) contaminated water. These results suggest that pathogenicity of HPAI H5 viruses and virus shedding for ducks is evolving, which may have implications for the risk of introduction of these viruses into the poultry sector.

Avipoxvirus detected in tumor-like lesions in a white-faced whistling duck (Dendrocygna viduata) / Avipoxvirus detectado em lesões tipo tumorais em uma marreca-irerê (Dendrocygna viduata)

Avipoxvirus is the etiological agent of the avian pox, a well-known disease of captive and wild birds, and it has been associated with tumor-like lesions in some avian species. A white-faced whistling duck (Dendrocygna viduata) raised in captivity was referred to a Veterinary Teaching Hospital in Northeast due to cutaneous nodules present in both wings. A few days after the clinical examination, the animal died naturally. Once submitted to necropsy, histopathological evaluation of the lesions revealed clusters of proliferating epithelial cells expanding toward the dermis. Some of these cells had round, well-defined, intracytoplasmic eosinophilic material suggestive of poxvirus inclusion (Bollinger bodies). PCR performed on the DNA extracted from tissue samples amplified a fragment of the 4b core protein gene (fpv167), which was purified and sequenced. This fragment of Avipoxvirus DNA present in these tumor-like lesions showed high genetic homology (100.0%) with other poxviruses detected in different avian species in several countries, but none of them were related to tumor-like lesions or squamous cell carcinoma. This is the first report of Avipoxvirus detected in tumor-like lesions of a white-faced whistling duck with phylogenetic analysis of the virus.(AU)

Avipoxvirus é o agente etiológico da varíola (bouba) aviária, uma doença bem descrita em aves de cativeiro e selvagens, tendo sido associada a lesões semelhantes a tumores em algumas dessas espécies. Uma marreca piadeira (Dendrocygna viduata), criada em cativeiro, foi atendida em um Hospital Veterinário na região nordeste devido à presença de nódulos cutâneos em ambas as asas. Alguns dias após o exame clínico, o animal veio a óbito naturalmente. A ave foi submetida à necropsia e coletados fragmentos das lesões para análise histopatológica, que revelou proliferação de células epiteliais expandindo para a derme. Algumas dessas células possuíam material eosinofílico intracitoplasmático e bem definido, sugestivo de inclusão de poxvírus (corpúsculos de Bollinger). A PCR realizada a partir do DNA extraído de amostras das lesões amplificou um fragmento do gene da proteína do núcleo 4b (fpv 167), que foi purificado e sequenciado. Esse fragmento de DNA de Avipoxvirus presente nas lesões relevou alta homologia genética (100,0%) com outros poxvírus detectados em diferentes espécies de aves em vários países, mas nenhum deles estava relacionado a lesões tumorais ou carcinoma espinocelular. Este é o primeiro relato de Avipoxvirus detectado em lesões semelhantes a tumores em uma marreca piadeira com caracterização molecular do vírus.(AU)

Avian Influenza Virus Prevalence and Subtype Diversity in Wild Birds in Shanghai, China, 2016-2018.

From 2016 to 2018, surveillance of influenza A viruses in wild birds was conducted in Shanghai, located at the East Asian-Australian flyway, China. A total of 5112 samples from 51 species of wild birds were collected from three different wetlands. The total three-year prevalence of influenza A viruses among them was 8.8%, as assessed using real-time polymerase chain reaction (PCR) methods, and the total prevalence was higher in Anseriformes (26.3%) than in the Charadriiformes (2.3%) and the other orders (2.4%) in the Chongmin wetlands. Anseriformes should be the key monitoring group in future surveillance efforts. The peak prevalence of influenza A viruses in Charadriiformes were in April and September, and in other bird orders, the peaks were in November and December. Twelve subtypes of haemagglutinin (HA; H1-H12) and eight subtypes of neuraminidase (NA; N1, N2, N4-N9) were identified in 21 different combinations. The greatest subtype diversity could be found in common teal, suggesting that this species of the bird might play an important role in the ecology and epidemiology of influenza A viruses in Shanghai. These results will increase our understanding of the ecology and epidemiology of influenza A viruses in wild bird hosts in eastern China, and provide references for subsequent surveillance of influenza A virus in wild birds in this area.

Polycistronic Genome Segment Evolution and Gain and Loss of FAST Protein Function during Fusogenic Orthoreovirus Speciation.

The Reoviridae family is the only non-enveloped virus family with members that use syncytium formation to promote cell-cell virus transmission. Syncytiogenesis is mediated by a fusion-associated small transmembrane (FAST) protein, a novel family of viral membrane fusion proteins. Previous evidence suggested the fusogenic reoviruses arose from an ancestral non-fusogenic virus, with the preponderance of fusogenic species suggesting positive evolutionary pressure to acquire and maintain the fusion phenotype. New phylogenetic analyses that included the atypical waterfowl subgroup of avian reoviruses and recently identified new orthoreovirus species indicate a more complex relationship between reovirus speciation and fusogenic capacity, with numerous predicted internal indels and 5'-terminal extensions driving the evolution of the orthoreovirus' polycistronic genome segments and their encoded FAST and fiber proteins. These inferred recombination events generated bi- and tricistronic genome segments with diverse gene constellations, they occurred pre- and post-orthoreovirus speciation, and they directly contributed to the evolution of the four extant orthoreovirus FAST proteins by driving both the gain and loss of fusion capability. We further show that two distinct post-speciation genetic events led to the loss of fusion in the waterfowl isolates of avian reovirus, a recombination event that replaced the p10 FAST protein with a heterologous, non-fusogenic protein and point substitutions in a conserved motif that destroyed the p10 assembly into multimeric fusion platforms.

Domestic ducks play a major role in the maintenance and spread of H5N8 highly pathogenic avian influenza viruses in South Korea.

The H5N8 highly pathogenic avian influenza viruses (HPAIVs) belonging to clade 2.3.4.4 spread from Eastern China to Korea in 2014 and caused outbreaks in domestic poultry until 2016. To understand how H5N8 HPAIVs spread at host species level in Korea during 2014-2016, a Bayesian phylogenetic analysis was used for ancestral state reconstruction and estimation of the host transition dynamics between wild waterfowl, domestic ducks and chickens. Our data support that H5N8 HPAIV most likely transmitted from wild waterfowl to domestic ducks, and then maintained in domestic ducks followed by dispersal of HPAIV from domestic ducks to chickens, suggesting domestic duck population plays a central role in the maintenance, amplification and spread of wild HPAIV to terrestrial poultry in Korea.

Influenza A/H4N2 mallard infection experiments further indicate zanamivir as less prone to induce environmental resistance development than oseltamivir.

Neuraminidase inhibitors (NAIs) are the gold standard treatment for influenza A virus (IAV). Oseltamivir is mostly used, followed by zanamivir (ZA). NAIs are not readily degraded in conventional wastewater treatment plants and can be detected in aquatic environments. Waterfowl are natural IAV hosts and replicating IAVs could thus be exposed to NAIs in the environment and develop resistance. Avian IAVs form the genetic basis for new human IAVs, and a resistant IAV with pandemic potential poses a serious public health threat, as NAIs constitute a pandemic preparedness cornerstone. Resistance development in waterfowl IAVs exposed to NAIs in the water environment has previously been investigated in an in vivo mallard model and resistance development was demonstrated in several avian IAVs after the exposure of infected ducks to oseltamivir, and in an H1N1 IAV after exposure to ZA. The N1 and N2 types of IAVs have different characteristics and resistance mutations, and so the present study investigated the exposure of an N2-type IAV (H4N2) in infected mallards to 1, 10 and 100 µg l-1 of ZA in the water environment. Two neuraminidase substitutions emerged, H274N (ZA IC50 increased 5.5-fold) and E119G (ZA IC50 increased 110-fold) at 10 and 100 µg l-1 of ZA, respectively. Reversion towards wild-type was observed for both substitutions in experiments with removed drug pressure, indicating reduced fitness of both resistant viruses. These results corroborate previous findings that the development of resistance to ZA in the environment seems less likely to occur than the development of resistance to oseltamivir, adding information that is useful in planning for prudent drug use and pandemic preparedness.

Virome heterogeneity and connectivity in waterfowl and shorebird communities.

Models of host-microbe dynamics typically assume a single-host population infected by a single pathogen. In reality, many hosts form multi-species aggregations and may be infected with an assemblage of pathogens. We used a meta-transcriptomic approach to characterize the viromes of nine avian species in the Anseriformes (ducks) and Charadriiformes (shorebirds). This revealed the presence of 27 viral species, of which 24 were novel, including double-stranded RNA viruses (Picobirnaviridae and Reoviridae), single-stranded RNA viruses (Astroviridae, Caliciviridae, Picornaviridae), a retro-transcribing DNA virus (Hepadnaviridae), and a single-stranded DNA virus (Parvoviridae). These viruses comprise multi-host generalist viruses and those that are host-specific, indicative of both virome connectivity (host sharing) and heterogeneity (host specificity). Virome connectivity was apparent in two well described multi-host virus species -avian coronavirus and influenza A virus- and a novel Rotavirus species that were shared among some Anseriform species, while virome heterogeneity was reflected in the absence of viruses shared between Anseriformes and Charadriiformes, as well as differences in viral abundance and alpha diversity among species. Overall, we demonstrate complex virome structures across host species that co-exist in multi-species aggregations.

New evidence for the east-west spread of the highly pathogenic avian influenza H5N1 virus between Central Asian and east Asian-Australasian flyways in China.

The spread of highly pathogenic avian influenza (HPAI) H5N1 virus is associated with wild fowl migration in East Asian-Australasian (EA) and Central Asian (CA) flyways. However, the spread of H5N1 virus between the two flyways is still unclear. Here, the movements of wild waterfowl were obtained from satellite tracking data covering seven bar-headed geese and three great black-headed gulls breeding in the Qinghai Lake area (along the EA flyway), and 20 whooper swans wintering in the Sanmenxia Reservoir area (at the CA flyway). From the 2688 samples that were screened from wild birds at Qinghai Lake after an outbreak of H5N1 in July 2015, four genomes of H5N1 virus were obtained from bar-headed geese. The results of phylogenetic analysis indicated that these H5N1 viruses belonged to clade 2.3.2.1c and their gene fragments were highly homologous with A/whooper swan/Henan/SMX1/2015 (H5N1) virus (ranging from 99.76% to 100.00%) isolated from a dead whooper swan from the Sanmenxia Reservoir area along the EA flyway in January 2015. Furthermore, the coincidental timing of the H5N1 outbreak with spring migration, together with phylogenetic evidence, provided new evidence of the east-to-west spread of HPAI H5N1 between the EA and CA migratory flyways of China.

Comparative micro-epidemiology of pathogenic avian influenza virus outbreaks in a wild bird population.

Understanding the epidemiological dynamics of highly pathogenic avian influenza virus (HPAIV) in wild birds is crucial for guiding effective surveillance and control measures. The spread of H5 HPAIV has been well characterized over large geographical and temporal scales. However, information about the detailed dynamics and demographics of individual outbreaks in wild birds is rare and important epidemiological parameters remain unknown. We present data from a wild population of long-lived birds (mute swans; Cygnus olor) that has experienced three outbreaks of related H5 HPAIVs in the past decade, specifically, H5N1 (2007), H5N8 (2016) and H5N6 (2017). Detailed demographic data were available and intense sampling was conducted before and after the outbreaks; hence the population is unusually suitable for exploring the natural epidemiology, evolution and ecology of HPAIV in wild birds. We show that key epidemiological features remain remarkably consistent across multiple outbreaks, including the timing of virus incursion and outbreak duration, and the presence of a strong age-structure in morbidity that likely arises from an equivalent age-structure in immunological responses. The predictability of these features across a series of outbreaks in a complex natural population is striking and contributes to our understanding of HPAIV in wild birds. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'. This issue is linked with the subsequent theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'.

Detection of avian metapneumovirus subtype A from wild birds in the State of São Paulo, Brazil / Detecção de metapneumovirus aviário subtipo A em aves silvestres no estado de São Paulo, Brasil

The present study investigated the circulation of avian metapneumovirus (aMPV) in wild birds in Brazil. To do so, 131 samples from 366 oropharyngeal or cloacal swabs collected from 18 species of birds were tested individually or in pools by RT-PCR. Samples detected by RT-PCR were selected for DNA sequencing. Thirteen (9.9%) samples were detected by the RT-PCR targeting the N gene and four out of 13 samples were sequenced. Sequencing results showed a high identity with the aMPV subtype A. Our results confirm the circulation of the aMPV subtype A in wild birds in Brazil even five years after its last detection.(AU)

O presente estudo investigou a circulação de metapneumovírus aviário em aves silvestres no Brasil. Para tanto, 131 amostras de 366 suabes orofaringeanos ou cloacais coletados de 18 espécies de aves foram testadas individualmente ou na forma de pools por RT-PCR. As amostras detectadas por RT-PCR foram selecionadas para sequenciamento. Treze (9,9%) das amostras foram detectadas por RT-PCR tendo o gene N como alvo; destas, quatro foram sequenciadas com sucesso. Resultados do sequenciamento mostraram alta identidade com o aMPV de subtipo A. Nossos resultados confirmam a circulação de aMPV subtipo A em aves silvestres no Brasil mesmo cinco anos após sua última detecção.(AU)

Comparative proteomic analysis revealed complex responses to classical/novel duck reovirus infections in the spleen tissue of Cairna moschata.

Duck reovirus (DRV), a member of the genus Orthoreovirus in the family Reoviridae, was first isolated from Muscovy ducks. The disease associated with DRV causes great economic losses to the duck industry. However, the responses of duck (Cairna moschata) to the classical/novel DRV (C/NDRV) infections are largely unknown. To reveal the relationship of pathogenesis and immune response, the proteomes of duck spleen cells under the control and C/NDRV infections were compared. In total, 5986 proteins were identified, of which 5389 proteins were quantified. The different accumulated proteins (DAPs) under the C/NDRV infections showed displayed various biological functions and diverse subcellular localizations. The proteins related to the serine protease system were siginificantly changed, suggesting that the activated serine protease system may play an important role under the C/NDRV infections. Furthermore, the differences in the responses to the C/NRDV infections between the duck liver and spleen tissues were compared. Only a small number of common DAPs were identified in both liver and spleen tissues, suggesting diversified pattern involved in the responses to the C/NRDV infections. However, the changes in the proteins involved in the serine protease systems were similar in both liver and spleen cells. Our data may give a comprehensive resource for investigating the responses to C/NDRV infections in ducks. SIGNIFICANCE: A newly developed MS/MS-based method involving isotopomer labels and 'tandem mass' has been applied to protein accurate quantification in current years. However, no studies on the responses of duck (Cairna moschata) spleen tissue to the classical/novel DRV (C/NDRV) infections have been performed. As a continued study of our previous report on the responses of duck liver tissue to the C/NDRV infections, the current study further compared the differences in the responses to the C/NRDV infections between the duck liver and spleen tissues. Our results will provide an opportunity to reveal the relationship of pathogenesis and immune response and basic information on the pathogenicity of C/NDRV in ducks.

Porcine Epidemic Diarrhea Virus and Porcine Deltacoronavirus not Detected in Waterfowl in the North American Mississippi Migratory Bird Flyway in 2013.

Cloacal swab samples collected from 538 migratory waterfowl along the Mississippi Migratory Bird Flyway in 2013 were tested for porcine epidemic diarrhea virus and porcine deltacoronavirus. Neither virus was detected in any of the samples, indicating that waterfowl likely did not contribute to the rapid spread of these viruses within central US.

Comparative proteomic analysis revealed complex responses to classical/novel duck reovirus infections in Cairna moschata.

Duck reovirus (DRV) is an typical aquatic bird pathogen belonging to the Orthoreovirus genus of the Reoviridae family. Reovirus causes huge economic losses to the duck industry. Although DRV has been identified and isolated long ago, the responses of Cairna moschata to classical/novel duck reovirus (CDRV/NDRV) infections are largely unknown. To investigate the relationship of pathogenesis and immune response, proteomes of C. moschata liver cells under the C/NDRV infections were analyzed, respectively. In total, 5571 proteins were identified, among which 5015 proteins were quantified. The differential expressed proteins (DEPs) between the control and infected liver cells displayed diverse biological functions and subcellular localizations. Among the DEPs, most of the metabolism-related proteins were down-regulated, suggesting a decrease in the basal metabolisms under C/NDRV infections. Several important factors in the complement, coagulation and fibrinolytic systems were significantly up-regulated by the C/NDRV infections, indicating that the serine protease-mediated innate immune system might play roles in the responses to the C/NDRV infections. Moreover, a number of molecular chaperones were identified, and no significantly changes in their abundances were observed in the liver cells. Our data may give a comprehensive resource for investigating the regulation mechanism involved in the responses of C. moschata to the C/NDRV infections.

Severe neurologic disease and chick mortality in crested screamers (Chauna torquata) infected with a novel Gyrovirus.

Gyroviruses are small, single stranded DNA viruses in the family Anelloviridae. In chickens, the type virus (chicken anemia virus; CAV) causes epidemic disease in poultry flocks worldwide. In 2007 and 2008, young crested screamers (Chauna torquata) at a zoo in Wisconsin, USA, died of neurologic disease with clinical and pathological features resembling CAV infection. Conventional diagnostics were negative, but molecular analyses revealed coinfection of an affected bird with three variants of a novel Gyrovirus lineage, GyV10. Analysis of ten additional screamers from this and another zoo revealed infection in all but one bird, with co-infections and persistent infections common. The association between GyV10 ("screamer anemia virus," provisionally) and the disease remains unproven, but certain immunological and neurologic features of the syndrome would expand the known pathologic consequences of Gyrovirus infection. To control the virus, autogenous vaccines, environmental decontamination, and management strategies to limit vertical and horizontal transmission might prove effective.

Pathotyping and genetic characterization of avian avulavirus-1 from domestic and wild waterfowl, geese and black swans in Pakistan, 2014 to 2017.

Twenty-nine avian avulavirus-1 viruses (AAvV-1s) from healthy domestic and wild ducks, geese and black swans collected in Pakistan between 2014-2017 have been pathotyped and genetically characterized. A phylogenetic analysis revealed that 21 of the isolates belonged to sub-genotype VIIi, whereas eight isolates were highly similar to vaccine-like viruses of genotype II. In addition to confirming the continued presence of sub-genotype VIIi AAvV-1s in Pakistan, this study identifies the probable spill-over of vaccine-like viruses from vaccinated poultry to wild and domestic waterfowl and, as such, has important implications for the control and management of Newcastle disease in Pakistan.

Migratory Whooper Swans Cygnus cygnus Transmit H5N1 Virus between China and Mongolia: Combination Evidence from Satellite Tracking and Phylogenetics Analysis.

In late 2014, a highly pathogenic avian influenza (hereafter HPAI) H5N1 outbreak infected whooper swans Cygnus cygnus wintering at the Sanmenxia Reservoir area, China, and raised concerns about migratory linkages between wintering and breeding grounds of whooper swans. In this study, 61 swans were satellite tracked from 2013 to 2016 to determine the spatial association of their migration routes and H5N1 outbreaks, and 3596 fecal samples were collected along the migration routes for virology testing. Swans departed the wintering grounds and migrated along the Yellow River, and flew over the Yin Mountains in China. The Brownian bridge movement model showed there was a high degree of spatiotemporal overlap between the core use area along the spring migration pathway and historical H5N1 events in China and Mongolia from 2005 to 2015. The H5N1 strain was isolated and phylogenetic analyses confirmed that the HA gene sequence generated is genetically similar to that of the epidemic strain at a previous wintering site (the Sanmenxia Reservoir area) along its flyway. Our results identified a previously unknown migratory link of whooper swans in central China with Mongolia and confirmed that the swans could carry the HPAI H5N1 virus during migration, resulting in long-distance transmission.