Genetic characterization and evolutionary analysis of 4 Newcastle disease virus isolate full genomes from waterbirds in South China during 2003–2007

Molecular characteristics and phylogenetic analysis of pigeon paramyxovirus type 1 isolates from pigeon meat farms in Shanghai (2009-2012)

The majority of pigeon paramyxovirus type 1 (PPMV-1) strains are generally non-pathogenic to chickens; however, they can induce severe illness and high mortality rates in pigeons, leading to substantial economic repercussions. The genomes of 11 PPMV-1 isolates from deceased pigeons on meat pigeon farms during passive monitoring from 2009 to 2012 were sequenced and analyzed using polymerase chain reaction and phylogenetic analysis. The complete genome lengths of 11 isolates were approximately 15,192 nucleotides, displaying a consistent gene order of 3'-NP-P-M-F-HN-L-5'. ALL isolates exhibited the characteristic motif of 112RRQKRF117 at the fusion protein cleavage site, which is characteristic of velogenic Newcastle disease virus. Moreover, multiple mutations have been identified within the functional domains of the F and HN proteins, encompassing the fusion peptide, heptad repeat region, transmembrane domains, and neutralizing epitopes. Phylogenetic analysis based on sequences of the F gene unveiled that all isolates clustered within genotype VI in class II. Further classification identified at least two distinct sub-genotypes, with seven isolates classified as sub-genotype VI.2.1.1.2.2, whereas the others were classified as sub-genotype VI.2.1.1.2.1. This study suggests that both sub-genotypes were implicated in severe disease manifestation among meat pigeons, with sub-genotype VI.2.1.1.2.2 displaying an increasing prevalence among Shanghai's meat pigeon population since 2011. These results emphasize the value of developing pigeon-specific vaccines and molecular diagnostic tools for monitoring and proactively managing potential PPMV-1 outbreaks.

A pigeon paramyxovirus type 1 isolated from racing pigeon as an inactivated vaccine candidate provides effective protection

Pigeon paramyxovirus type 1 (PPMV-1), a variant of Newcastle disease virus (NDV), causes severe Newcastle disease (ND) in pigeons. However, there is no PPMV-1 vaccine available worldwide. In this study, a strain of PPMV-1 was isolated from outbreaks in a vaccinated racing pigeon (Columbia livia) loft in China, namely, PPMV-1/pigeon/Gansu/China/02/2020 (GS02). Experimental infection with GS02 showed mortality rates of 100% and 87.50% in 4- and 12-week-old pigeons, respectively, suggesting that GS02 is virulent and more sensitive to young pigeons. The whole genome of GS02 determined the fusion (F) protein possessing virulence cleavage site ¹¹²RRQKRF¹¹⁷. Phylogenetic analysis indicated that GS02 was a subgenotype VI.2.1.1.2.2 (VIk) of Class II NDV and more closely related to the JS/06/20/Pi (MW271791) strain, but it was far from the genetic distance from the commercial vaccine chicken-origin La Sota strain. Using inactivated GS02 as a vaccine candidate and inactivated vaccine La Sota to immunize the pigeons, both of them provided complete protection against GS02 challenge. The GS02 vaccine candidate induced higher antibody titers than the La Sota vaccine, and cross-reactivity testing showed antigenically slight differences between GS02 and La Sota. These results indicated that the GS02 candidate could be a potential pigeon-derived vaccine for the prevention and control of PPMV-1 in pigeons.

mRNA expression and functional analysis of chicken IFIT5 after infected with Newcastle disease virus

Innate immunity is the first line against the invasion of pathogenic microorganisms. Over the past several years, the antiviral activity and mechanisms of the IFIT5 gene have been confirmed in mammals. However, more information is needed on the role of IFIT5 in response to viral infection in chickens. In this study, we examined the mRNA expression profile of chicken IFIT5 (chIFIT5) in different tissues and explored how chIFIT5 transduces upstream signaling to the downstream adaptor. Relative mRNA expression level of chIFIT5 was the highest in spleen and expression level of chIFIT5 was significantly up-regulated following Newcastle disease virus (NDV) infection, and polyinosinic:polycytidylic acid [poly (I:C)]- and poly(deoxyadenylic-thymidylic) [poly (dA:dT)]-triggered antiviral immune responses. Chicken MDA5, MAVS, and IRF7 positively regulated the mRNA expression of chIFIT5. Overexpression of chIFIT5 could promote IRF7- and NF-κB-mediated gene expression following NDV infection or transfection with poly (I:C). These results suggested that chIFIT5 is an important enhancer of the innate immunity response.

Evolutionary Dynamics and Age-Dependent Pathogenesis of Sub-Genotype VI.2.1.1.2.2 PPMV-1 in Pigeons

Pigeon paramyxovirus type 1 (PPMV-1) infection causes high morbidity in pigeons, resulting in a significant burden to the poultry industry. In this study, we isolated three PPMV-1 strains from diseased pigeons collected in Guangdong Province, South China, from June 2017 to April 2019. Genetic analysis revealed that these three PPMV-1 strains and most of the PPMV-1 strains isolated from China after 2011 were clustered into sub-genotype VI.2.1.1.2.2. Our Bayesian analysis revealed that the VI.2.1.1.2.2 viruses might have originated in Europe. Phylogeographic analyses revealed that East and South China might have played a key role in seeding the VI.2.1.1.2.2 PPMV-1 epidemic in China. To characterize the effect of age at infection on the outcome of PPMV-1 infection in pigeons, we investigated the pathogenesis and transmission of the pigeon/Guangdong/GZ08/2017 (GZ08) virus in 3-, 6-, and 12-week-old pigeons. Two of six 12-week-old pigeons inoculated with GZ08 survived, and all of the 3- and 6-week-pigeons inoculated with GZ08 died. Moreover, the GZ08 virus could be transmitted to 3-, 6-, and 12-week-old naïve contact pigeons. The lethality of the GZ08 virus through contact with 3-, 6-, and 12-week-old pigeons was 100%, 66.7%, and 0%, respectively, suggesting that the transmissibility of the GZ08 virus was stronger in young pigeons. These findings demonstrated that East and South China was the epicenter for dissemination of VI.2.1.1.2.2 PPMV-1, and age at infection has an impact on the outcome of PPMV-1 infection in pigeons.

Self-capping of nucleoprotein filaments protects the Newcastle disease virus genome

Non-segmented negative-strand RNA viruses, such as measles, ebola and Newcastle disease viruses (NDV), encapsidate viral genomic RNAs into helical nucleocapsids, which serve as the template for viral replication and transcription. Here, the clam-shaped nucleocapsid structure, where the NDV viral genome is sequestered, was determined at 4.8 Å resolution by cryo-electron microscopy. The clam-shaped structure is composed of two single-turn spirals packed in a back-to-back mode. This tightly packed structure functions as a seed for the assembly of a nucleocapsid from both directions, facilitating the growth of double-headed filaments with two separate RNA strings inside. Disruption of this structure by mutations in its loop interface yielded a single-headed unfunctional filament.

A genotype VII Newcastle disease virus-like particles confer full protection with reduced virus load and decreased virus shedding

Newcastle disease (ND) is one of the most severe avian infectious disease inflicting a great loss on poultry industry worldwide. The control of ND relies on proper vaccination strategies. The vaccine strains of Newcastle disease virus (NDV) mainly belong to genotype I, II or III, which cannot fully prohibit virus shedding against the prevalent genotype VII virulent strain attack. To develop a safe, genotype matched vaccine candidate, we employed a bac-to-bac expression system and constructed a genotype VII NDV strain based virus-like particles (NDV VLPs). It was constructed with NDV M protein as the skeleton, and protective antigen F and HN proteins displayed on the surface. The NDV VLPs exhibited a similar appearance to the live NDV particles, but with denser F and HN proteins displayed on the surface. The immunization assay indicated that NDV VLPs stimulated a longer protection period, less tissue virus loading and shorter virus shedding period than the commercialized LaSota-formulated vaccine when challenged with genotype VII NDV strain. These results proposed the potential role of NDV VLPs as an alternative to current live genotype unmatched vaccine for the control and eliminate NDV in the avian flocks.

The virulence of NDV NA-1 strain regulated by the 3' leader or 5' trailer sequences

The 3' and 5' terminal regions of Newcastle disease virus (NDV) genome are cis-acting regulatory elements involved in replication, transcription, and packaging of genomic and anti-genomic viral RNA. There are 6 different nucleotides (nts) at the 3' and 34 different nts at the 5' end of genome in the velogenic NA-1 strain and lentogenic LaSota strain, sharing 90.00% and 70.18% identity, respectively. We investigated the roles of 3' and 5' terminus in the NA-1 strain in viral replication, virulence and pathogenicity. Three NA-1 strain-based recombinant viruses (rNA-L, rNA-T, and rNA-LT) were generated using reverse genetics by either replacing the 3' leader or 5' trailer sequence of NA-1 strain or both with the corresponding sequences of the LaSota strain. Viral replication kinetics and pathogenicity of rNA-L and rNA-T were indistinguishable to that of the parental NA-1 strain, demonstrating that individual replacement or 3' or 5' terminal sequences had little influence. However, the synchronal replacement of both 3' and 5' terminal sequences resulted in decreased viral plaque size, reduced virulence and weaker pathogenicity in 2-week-old chickens. Therefore, our results suggest that the 3' and 5' terminal sequences of NDV genome could only influence the viral virulence when worked collaboratively, while separate replacement would not alter its biological characteristics.

Pathobiology of Avian avulavirus 1: special focus on waterfowl

Avian avulaviruses serotype 1 (abbreviated as APMV-1 for the historical name avian paramyxovirus 1) are capable of infecting a wide spectrum of avian species with variable clinical symptoms and outcomes. Ease of transmission has allowed the virus to spread worldwide with varying degrees of virulence depending upon the virus strain and host species. The emergence of new virulent genotypes from global epizootics, and the year-to-year genomic changes in low and high virulence APMV-1 imply that distinct genotypes of APMV-1 are simultaneously evolving at different geographic locations across the globe. This vast genomic diversity may be favoured by large variety of avian species susceptibility to APMV-1 infection, and by the availability of highly mobile wild birds. It has long been considered that waterfowls are not sensitive to APMV-1 and are unable to show any clinical signs, however, outbreaks from the 90's contradict these concepts. The APMV-1 isolates are increasingly reported from the waterfowl. Waterfowl have strong innate immune responses, which minimize the impact of virus infection, however, are unable to prevent the viral shedding. Numerous APMV-1 are carried by domestic waterfowl intermingling with terrestrial poultry. Therefore, commercial ducks and geese should be vaccinated against APMV-1 to minimize the virus shedding and for the prevention the transmission. Genetic diversity within APMV-1 demonstrates the need for continual monitoring of viral evolution and periodic updates of vaccine seed-strains to achieve efficient control and eradication of APMV-1 in waterfowls.

Adaptation of Newcastle Disease Virus (NDV) in Feral Birds and their Potential Role in Interspecies Transmission

Introduction:

Newcastle Disease (ND), caused by Avian avulavirus 1 (AAvV 1, avulaviruses), is a notifiable disease throughout the world due to the economic impact on trading restrictions and its embargoes placed in endemic regions. The feral birds including aquatic/migratory birds and other wild birds may act as natural reservoir hosts of ND Viruses (NDVs) and may play a remarkable role in the spread of the virus in environment. In addition, other 19 avulaviruses namely: AAvV 2 to 20, have been potentially recognized from feral avian species.

Expalantion:

Many previous studies have investigated the field prevailing NDVs to adapt a wide range of susceptible host. Still the available data is not enough to declare the potential role of feral birds in transmission of the virus to poultry and/or other avian birds. In view of the latest evidence related to incidences of AAvVs in susceptible avian species, it is increasingly important to understand the potential of viruses to transmit within the domestic poultry and other avian hosts. Genomic and phylogenomic analysis of several investigations has shown the same (RK/RQRR↓F) motif cleavage site among NDV isolates with same genotypes from domestic poultry and other wild hosts. So, the insight of this, various semi-captive/free-ranging wild avian species could play a vital role in the dissemination of the virus, which is an important consideration to control the disease outbreaks. Insufficient data on AAvV 1 transmission from wild birds to poultry and vice versa is the main constraint to understand about its molecular biology and genomic potential to cause infection in all susceptible hosts.

Conclusion:

The current review details the pertinent features of several historical and contemporary aspects of NDVs and the vital role of feral birds in its molecular epidemiology and ecology.

Genetic diversity of avian avulavirus 1 (Newcastle disease virus genotypes VIg and VIIb) circulating in wild birds in Kazakhstan

In order to improve current understanding of the molecular epidemiology of avian avulavirus 1 (AAvV-1, formerly avian paramyxovirus 1) in wild birds in Kazakhstan, 860 cloacal swab samples were evaluated. Samples were collected from 37 families of wild birds in nine different regions in the years 2011 and 2014. Overall, 54 positive samples (4.2%) were detected from 17 different families of wild birds, and 16 AAvV-1 isolates were characterized. Three of the isolates contained the fusion protein cleavage site motif RRQKR, and 13 contained KRQKR, which is typical for pathogenic strains of AAvV-1. The AAvV-1 isolates were found to belong to the genotypes VIg and VIIb.

Phylogenetic, antigenic and biological characterization of pigeon paramyxovirus type 1 circulating in China

Background

For many years, ND has been one of the most important infectious pigeon diseases in China. In recent years, a high mortality has been observed in ND-infected pigeons in China. Mortality is from 40% to 80% or 100% in some cases.

Methods

The full-length genomes of four pigeon paramyxovirus type 1 (PPMV-1) strains, which were isolated from infected pigeons in China in 2012 and 2013, were sequenced and analyzed to determine the phylogenetic characteristics of PPMV-1 circulating in pigeons of China in recent years. Furthermore, cross hemagglutination inhibition and cross virus neutralization assays, as well as animal experiments were conducted to determine the antigenicity and pathogenicity of those viruses. Proteolytic cleavage sites (residues 112–117) of the F proteins were identified as the typical virulence motif, ¹¹²RRQKR↓F¹¹⁷ for all four PPMV-1 strains investigated.

Results

Phylogenetic analysis based on sequences of complete genomes and F gene revealed that the four PPMV-1 isolates and most of recent isolates in China were highly homologous to European isolates from 1998 to 2011. All those isolates were clustered in one clade of genotype VI NDV, termed as subgroup 4bii f. The R value was calculated based on cross hemagglutination inhibition and cross virus neutralization results, and confirmed antigenic difference of the PPMV-1 strains isolated in 2013 from the LaSota vaccine strain. Several mutations were identified in the surface glycoproteins F and HN, which probably gave rise to those antigenic differences.

Conclusion

Our result suggested that the PPMV-1 strain prevailing in China in the last decade diverged from a common ancestor and was presumably transmitted from Europe. PPMV-1 isolates displayed obvious antigenic differences from vaccine strain LaSota. Even though PPMV-1 did not cause high mortality in experimental pigeons, the infected pigeons were exhibiting viral shedding for 3 weeks after infection, suggesting PPMV-1 is a potential threat to NDV control worldwide.

Electronic supplementary material

The online version of this article (10.1186/s12985-017-0857-7) contains supplementary material, which is available to authorized users.

Spillover of Newcastle disease viruses from poultry to wild birds in Guangdong province, southern China

Despite intensive vaccination programs in many countries, including China, Newcastle disease has been reported sporadically and is still a significant threat to the poultry industry in China. Newcastle disease virus (NDV) is infectious for at least 250 bird species, but the role of wild birds in virus epidemiology remains largely unknown. Fourteen NDV isolates were obtained from 2040 samples collected from wild birds or the environment in Guangdong province, southern China, from 2013 to 2015. The isolation rate was the highest in the period of wintering and lowest during the periods of spring migration, nesting, and postnesting. A maximum clade credibility phylogenetic analysis revealed that at least four genotypes circulate in southern China: three class II genotypes (II, VI, and IX) and one class I (1b). We also demonstrated that most isolates from wild birds were highly similar to isolates from poultry, and two isolates were linked to viruses from wild birds in northern China. These data suggested that wild birds could disseminate NDV and poultry-derived viruses may spillover to wild birds. Accordingly, vaccine development and poultry management strategies should be considered to prevent future NDV outbreaks, particularly given the strength of the poultry industry in developing countries, such as China.

Phylogenetic and Pathotypic Characterization of Newcastle Disease Viruses Circulating in South China and Transmission in Different Birds

Although Newcastle disease virus (NDV) with high pathogenicity has frequently been isolated in poultry in China since 1948, the mode of its transmission among avian species remains largely unknown. Given that various wild bird species have been implicated as sources of transmission, in this study we genotypically and pathotypically characterized 23 NDV isolates collected from chickens, ducks, and pigeons in live bird markets (LBMs) in South China as part of an H7N9 surveillance program during December 2013–February 2014. To simulate the natural transmission of different kinds of animals in LBMs, we selected three representative NDVs—namely, GM, YF18, and GZ289—isolated from different birds to evaluate the pathogenicity and transmission of the indicated viruses in chickens, ducks, and pigeons. Furthermore, to investigate the replication and shedding of NDV in poultry, we inoculated the chickens, ducks, and pigeons with 10⁶ EID₅₀ of each virus via intraocular and intranasal routes. Eight hour after infection, the naïve contact groups were housed with those inoculated with each of the viruses as a means to monitor contact transmission. Our results indicated that genetically diverse viruses circulate in LBMs in South China's Guangdong Province and that NDV from different birds have different tissue tropisms and host ranges when transmitted in different birds. We therefore propose the continuous epidemiological surveillance of LBMs to support the prevention of the spread of these viruses in different birds, especially chickens, and highlight the need for studies of the virus–host relationship.

Genetic characterization and evolutionary analysis of Newcastle disease virus isolated from domestic duck in South Korea

Domestic ducks are considered a potential reservoir of Newcastle disease virus. In the study, a Newcastle disease virus (NDV) isolated from a domestic duck during surveillance in South Korea was characterized. The complete genome of the NDV isolate was sequenced, and the phylogenetic relationship to reference strains was studied. Phylogenetic analysis revealed that the strain clustered in genotype I of Class II ND viruses, has highly phylogenetic similarity to NDV strains isolated from waterfowl in China, but was distant from the viruses isolated in chickens and vaccine strains used in South Korea. Pathogenicity experiment in chickens revealed it to be a lentogenic virus. The deduced amino acid sequence of the cleavage site of the fusion (F) protein confirmed that the isolate contained the avirulent motif (112)GKQGRL(117) at the cleavage site and caused no apparent disease in chickens and ducks. With phylogeographic analysis based on fusion gene, we estimate the origin of an ancestral virus of the isolate and its sister strain located in China around 1998. It highlights the need of continuous surveillance to enhance current understanding of the molecular epidemiology and evolution of the pathogenic strains.

Isolation, Identification, and Sequencing of a Goose-Derived Newcastle Disease Virus and Determination of Its Pathogenicity

In August 2010, geese in the Meihekou area of Jilin province in China were found to be infected by a pathogen that caused a disease similar to Newcastle disease. To determine the causative agent of the infections, a virus was isolated from liver tissues of infected geese, followed by a pathogenicity determination. The isolated virus was named NDV/White Goose/China/Jilin(Meihekou)/MHK-1/2010. Specific primers were designed to amplify the whole genome of the MHK-1 virus, followed by sequencing and splicing of the entire genome. Sequencing and phylogenetic analysis of MHK-1 showed that the isolate was a virulent strain of Newcastle disease virus. The MHK-1 genome is 15,192 nucleotides long, and it belongs to the class II branch of Newcastle disease viruses, as evidenced by the amino acid sequence (112R-R-Q-K-R-F117) of the F protein. The hemagglutinin titer was 1:128 to 1:512. The chicken embryo mean death time, the intracerebral pathogenicity index, and the median lethal dose of chicken embryos of MHK-1 were 43 hr, 1.63, and 10(9)/ml, respectively, which revealed that the newly isolated MHK-1 strain is strongly pathogenic to geese.

Genomic Characterizations of Six Pigeon Paramyxovirus Type 1 Viruses Isolated from Live Bird Markets in China during 2011 to 2013

The genomes of six pigeon paramyxovirus type 1 (PPMV-1) isolated from symptomless pigeons in live poultry markets during the national active surveillance from 2011 to 2013 were sequenced and analyzed in this study. The complete genome lengths of all isolates were 15,192 nucleotides with the gene order of 3’-NP-P-M-F-HN-L-5’. All isolates had the same motif of ¹¹²RRQKRF¹¹⁷ at the cleavage site of the fusion protein, which was typical of velogenic Newcastle disease virus (NDV). Several mutations were identified in the functional domains of F and HN proteins, including fusion peptide, heptad repeat region, transmembrane domains and neutralizing epitopes. Phylogenetic analysis based on sequences of complete genomes and six genes revealed that all isolates belonged to genotype VI in class II, but at least 2 sub-genotypes were identified. Most isolates were placed into sub-genotype VIb with the exception of pi/GX/1015/13, which was classified in sub-genotype VIa. The obvious antigenic difference between PPMV-1 isolates and La Sota strain was found based on the R-value calculated by cross hemagglutination inhibition (HI) assay. These results provided the evidence that PPMV-1 could be detected from healthy pigeons, and our study may be useful in designing vaccines used in pigeon, and developing molecular diagnostic tools to monitor and prevent future PPMV-1 outbreaks.

Generation and evaluation of a recombinant genotype VII Newcastle disease virus expressing VP3 protein of Goose parvovirus as a bivalent vaccine in goslings

Newcastle disease virus (NDV) and Goose parvovirus (GPV) are considered to be two of the most important and widespread viruses infecting geese. In this study, we generated a recombinant rmNA-VP3, expressing GPV VP3 using a modified goose-origin NDV NA-1 by changing the multi-basic cleavage site motif RRQKR↓F of the F protein to the dibasic motif GRQGR↓L as that of the avirulent strain LaSota as a vaccine vector. Expression of the VP3 protein in rmNA-VP3 infected cells was detected by immunofluorescence and Western blot assay. The genetic stability was examined by serially passaging 10 times in 10-day-old embryonated SPF chicken eggs. Goslings were inoculated with rmNA-VP3 showed no apparent signs of disease and developed a strong GPV and NDV neutralizing antibodies response. This is the first study demonstrating that recombinant NDV has the potential to serve as bivalent live vaccine against Goose parvovirus and Newcastle disease virus infection in birds.

Phylogenetic analysis of Newcastle disease viruses isolated from wild birds in the Poyang Lake region of China

Newcastle disease virus (NDV) causes a highly contagious viral disease in poultry and wild birds, and it can cause significant economic loss worldwide. Eight viral strains were isolated by inoculating embryonated chicken eggs from the Poyang Lake region of China with swab samples. All eight of the NDV isolates were identified as class I genotype 3 strains, but they diverged notablely from class II viruses. Further analysis revealed that all eight NDV isolates were lentogenic strains containing the (112)ERQER↓L(117) motif at the F protein cleavage site. The strains were highly identical and were more species specific (chicken and waterfowl) than site specific (Nanchang and Duchang regions). The close phylogenetic proximity of these isolates indicates that viral transmission may happen between poultry and wild birds. Our study demonstrates that lentogenic class I NDVs exist in clinically healthy wild waterfowl and poultry within the Poyang Lake region. Active surveillance of these viruses to determine their evolution and origin is one of the most realistic strategies for preventing and controlling NDV outbreaks.

Phylogenetic analysis of avian paramyxovirus serotype-1 in pigeons in Japan

To understand the epidemiology of Avian paramyxovirus serotype-1 (APMV-1) in pigeons in Japan, phylogenetic analysis was comprehensively conducted based on partial fusion protein gene using isolate from the surveillance of this virus with previously known Japanese pigeon strains. This surveillance was conducted using feces obtained from domestic pigeons collected in 40 prefectures throughout Japan from June 2011 to March 2013. From a total of 1,021 samples, a single virus (APMV1/pigeon/Japan/Kanagawa/2013: JP/Kanagawa-pg/2013) was isolated. All Japanese pigeon APMV-1 strains were clustered into a single genetic lineage, which was termed VIb/1 by phylogenetic analysis based on the F gene including the sequence of the cleavage site. These APMV-1 strains were further subdivided into four subgroups identified over 4 separate timeframes: 1984–1995 (group 1), 1995–2000 (group 2), 2001–2007 (group 3) and the novel subgroup isolated in 2013 (group 4). Each subgroup has specific amino acid motifs at a cleavage site of the F protein, namely, ¹¹²GRQKR-F¹¹⁷(except for one strain), ¹¹²RRKKR-F¹¹⁷, ¹¹²RRQKR-F¹¹⁷ and ¹¹²RRQKR-F¹¹⁷, respectively. Our data suggest that Japanese APMV-1 strains from pigeons were diverse and reinforced the possibility that there were multiple introduction routes from foreign countries into Japan.

Genetic characterization and pathogenicity assessment of Newcastle disease virus isolated from wild peacock

The continued spread and occurrence of Newcastle disease virus (NDV) has posed potential threat to domestic poultry industry around the globe. Mainly, wild avian species has always been implicated for the natural reservoir for virus and spread of the disease. In the present study, we report the isolation of Newcastle disease virus (NDV/Peacock/India/2012) in necropsy brain tissue sample of wild peacock from North India. Complete genome of the virus was found to be 15,186 nucleotides (nts) with six genes in order of 3'-N-P-M-F-HN-L-5', which was limited by 55-nts leader region at the 3' end and a 114-nts trailer sequence at 5' end. Sequence analysis of fusion protein revealed the dibasic amino acid cleavage site (112)R-R-Q-K-R-F(117), a characteristic motif of virulent virus. Phylogenetic analysis placed the isolate in genotype II of Newcastle disease virus showing the lowest mean percent divergence (6 %) with other genotype II counterparts. The isolate was characterized as mesogenic (intermediate pathotype) based on the mean death time (63 h) in embryonated chicken eggs and the intra-cerebral pathogenicity index (1.40) in day-old chicks. The report emphasizes the dynamic ecology of NDV strains circulating in a wild avian host during the outbreak of 2012 in North India. Further the genotypic and pathotypical characterizations of the isolate could help in development of homologous vaccine against NDV strain circulating in avian population.

Phylogenetic relationships and pathogenicity variation of two Newcastle disease viruses isolated from domestic ducks in Southern China

BACKGROUND

Newcastle disease (ND) is an OIE listed disease caused by virulent avian paramyxovirus type 1 (APMV-1) strains, which is enzootic and causes large economic losses in the poultry sector. Genotype VII and genotype IX NDV viruses were the predominant circulating genotype in China, which may possibly be responsible for disease outbreaks in chicken flocks in recent years. While ducks and geese usually have exhibited inapparent infections.

METHODS

In the present study, we investigate the complete genome sequence, the clinicopathological characterization and transmission of two virulent Newcastle disease viruses, SS-10 and NH-10, isolated from domestic ducks in Southern China in 2010.

RESULTS

F, and the complete gene sequences based on phylogenetic analysis demonstrated that SS-10 (genotype VII) and NH-10 (genotype IX) belongs to class II. The deduced amino acid sequence was (112)R-R-Q-K/R-R-F(117) at the fusion protein cleavage site. Animal experiment results showed that the SS-10 virus isolated from ducks was highly pathogenic for chickens and geese, but low pathogenic for ducks. It could be detected from spleen, lung, kidney, trachea, small intestine, bursa of fabricius, thymus, pancreas and cecal tonsils, oropharyngeal and cloacal swabs, and could transmit to the naive contact birds. Moreover, it could transmit to chickens, ducks and geese by naive contact. However, the NH-10 virus isolated from ducks could infect some chickens, ducks and geese, but only caused chickens to die. Additionally, it could transmit to the naive contact chickens, ducks, and geese.

CONCLUSION

The two NDV isolates exhibited different biological properties with respect to pathogenicity and transmission in chickens, ducks and geese. Therefore, no species-preference exists for chicken, duck or goose viruses and more attention should be paid to the trans-species transmission of VII NDVs between ducks, geese and chickens for the control and eradication of ND.

Surveillance of avian paramyxovirus in migratory waterfowls in the San-in region of western Japan from 2006 to 2012

Relatively little is known about the distribution of avian paramyxoviruses (APMVs) among wild birds in Japan. Surveillance of APMV in migratory waterfowl was conducted in the San-in region of western Japan during winters of 2006 to 2012. A total of 16 avian paramyxoviruses consisting of 3 lentogenic Newcastle disease viruses (NDVs), 12 APMV-4 and 1 APMV-8 were isolated from 1,967 wild-bird fecal samples. The results show that NDV and APMV-4 are relatively widely distributed among wild waterfowl that migrate to Japan from northern regions. Phylogenetic analysis revealed that there was no genetic relationship between the isolates from wild birds and domestic poultry in Japan. However, surveillance of APMVs in wild waterfowl needs to be conducted due to the pathogenic potential of these isolates in domestic poultry.

Phylogenetic characterization and virulence of two Newcastle disease viruses isolated from wild birds in China

Wild birds are considered as a natural reservoir of Newcastle disease virus (NDV). However, there is no information about genotype IX NDV from wild birds, especially from Columbiformes. In this study, two genotype IX NDV viruses were isolated from wild birds. One was from Eurasian Blackbird, while the other was from Spotted-necked dove. After purification by plaque technique, complete genomes of both viruses were sequenced. Phylogenetic analysis of partial fusion (F) gene and complete genome indicated both strains belonged to genotype IX. Based on intracerebral pathogenicity index (ICPI), the virus from Eurasian Blackbird was velogenic virus, while the strain from Spotted-necked dove was lentogenic virus. However, both strains showed one of velogenic cleavage sites. In addition, the strain from Eurasian Blackbird showed greater replication ability and generated larger fusion foci in vitro than that of strain from Spotted-necked dove. Comparing all the corresponding protein sequences of both strains, there were only 9 different amino acid residues between them. Furthermore, after analysis of these differences, the information about lentogenic NDV with multi-basic cleavage site was presented.

Molecular epidemiology of outbreak-associated and wild-waterfowl-derived newcastle disease virus strains in Finland, including a novel class I genotype

Newcastle disease (ND) is a highly contagious, severe disease of poultry caused by pathogenic strains of Newcastle disease virus (NDV; or avian paramyxovirus-1). NDV is endemic in wild birds worldwide and one of the economically most important poultry pathogens. Most of the published strains are outbreak-associated strains, while the apathogenic NDV strains that occur in wild birds, posing a constant threat to poultry with their capability to convert into more virulent forms, have remained less studied. We screened for NDV RNA in cloacal and oropharyngeal samples from wild waterfowl in Finland during the years 2006 to 2010: 39 of 715 birds were positive (prevalence, 5.5%). The partial or full-length F genes of 37 strains were sequenced for phylogenetic purposes. We also characterized viruses derived from three NDV outbreaks in Finland and discuss the relationships between these outbreak-associated and the wild-bird-associated strains. We found that all waterfowl NDV isolates were lentogenic strains of class I or class II genotype I. We also isolated a genetically distinct class I strain (teal/Finland/13111/2008) grouping phylogenetically together with only strain HIECK87191, isolated in Northern Ireland in 1987. Together they seem to form a novel class I genotype genetically differing from other known NDVs by at least 12%.