Paramyxovirus Type Research Articles

RAA-CRISPR/Cas12a-Mediated Rapid, Sensitive, and Onsite Detection of Newcastle Disease in Pigeons.

Pigeon Newcastle disease, caused by pigeon paramyxovirus type 1 (PPMV-1), is a significant infectious disease in pigeons that can result in substantial mortality and poses a severe threat to the pigeon industry. The rapid and accurate onsite diagnosis of pigeon disease is crucial for timely diagnosis and the implementation of effective prevention and control measures. In this study, we established a rapid detection method for PPMV-1 based on recombinase-aided amplification (RAA) and CRISPR/Cas12a. The RAA primers target the conserved regions of the L gene for preamplification in clinical nucleic acid samples, followed by CRISPR/Cas12a detection of the target gene. Visualization could be achieved by combination with a lateral flow dipstick (LFD). This method demonstrated high specificity, showing no cross-reactivity with non-PPMV-1 samples. The sensitivity of the method assessed by fluorescence analysis reached 100 copies/µL, and when it was combined with an LFD, the sensitivity was 103 copies/µL. The constructed RAA-CRISPR/Cas12a-LFD visual detection method was applied to clinical sample testing and was found to enable the rapid and accurate detection of swab samples and tissue specimens. Its sensitivity was consistent with the current gold standard, quantitative real-time PCR results. The RAA-CRISPR/Cas12a-LFD detection method we developed provides a novel approach for the rapid, simple, precise, and specific onsite diagnosis of pigeon Newcastle disease.

Phylogenetic analysis, genetic diversity, and epidemiology of pigeon paramyxovirus type 1 in China.

Pigeon paramyxovirus type 1 (PPMV-1) poses significant economic challenges to the pigeon industry in China. However, information about the prevalence, genetic diversity, and epidemiology of PPMV-1 in China is still lacking. In this study, we isolated six strains of PPMV-1 from Hubei and Zhejiang provinces in 2022. All six isolates were found to belong to subgenotype VI.2.1.1.2.2. Five of them were identified as mesogenic and one as lentogenic. Multiple mutations were observed in the F and HN proteins of these isolates. Comprehensive analysis of global PPMV-1 strains highlighted the dominance of genotype VI, showing that VI.2.1.1.2.2 has been the dominant subgenotype since 2011. We also identified 36 host-specific amino acid substitutions that are unique to PPMV-1 in comparison to chicken-origin NDVs. The data reported here contribute to our understanding of the epidemiology, genetic diversity, and prevalence of PPMV-1 and serve as a valuable reference for the prevention and control of PPMV-1.

The first emergence of paramyxovirus type 12 in wild birds in mainland, China

Avian paramyxoviruses (APMV) belong to the subfamily Avulavirinae of the family Paramyxoviridae and include 22 distinct subtypes or serotypes (1-22). Avian paramyxovirus serotype 12 (APMV-12) is found sporadically in wild birds worldwide, and reports from only Italy and Taiwan have been published to date; information on its genetic variation and biological characteristics is still limited. In this study, 3 APMV-12 strains, designated WB19, LY9, and LY11, were isolated from 8643 wild bird faecal samples during the annual influenza virus surveillance of wild birds in Guangdong, China between 2018 and 2024, which is first reported in mainland China. The complete genomes of the 3 viruses with 6 gene segments, 3'-N-P-M-F-HN-L-5', were 15,231 nt in length. Phylogenetic analysis based on the whole genome showed that the 3 APMV-12 strains had the highest homology with an APMV-12 strain isolated from Taiwan in 2015, followed by the prototype APMV-12 strains isolated from mallard ducks in Italy in 2005. Genetic analysis of the whole gene of each of them indicated that they were derived from a Eurasian lineage. This study provides additional evidence that wild birds transmit viruses between countries, and this should be monitored to understand APMV transmission, evolution and epidemiology.

Isolation and Genetic Characterization of Genotype VII Velogenic Pathotype Newcastle Disease Virus from Commercial Chicken Farms in Central Ethiopia, Distinct from the Local Vaccine Strains.

Newcastle disease (ND) is caused by virulent strains of avian paramyxovirus type 1, also known as Newcastle disease virus (NDV). Despite vaccination, the frequency of reported outbreaks in Ethiopia has increased. From January to June 2022, an active outbreak investigation was conducted in six commercial chicken farms across areas of central Ethiopia to identify the circulating NDV strains. Thirty pooled tissue specimens were collected from chickens suspected of being infected with NDV. A questionnaire survey of farm owners and veterinarians was also carried out to collect information on the farms and the outbreak status. NDV was isolated using specific-pathogen-free (SPF)-embryonated chicken eggs and detected using haemagglutination and the reverse transcriptase-polymerase chain reaction (RT-PCR). The genotype and virulence of field NDV isolates were determined using phylogenetic analysis of fusion (F) protein gene sequences and the mean death time (MDT) test in SPF-embryonated chicken eggs. The questionnaire results revealed that ND caused morbidity (23.1%), mortality (16.3%), case fatality (70.8%), and significant economic losses. Eleven of thirty tissue specimens tested positive for NDV using haemagglutination and RT-PCR. The MDT testing and sequence analysis revealed the presence of virulent NDV classified as genotype VII of class II velogenic pathotype and distinct from locally used vaccine strains (genotype II). The amino acid sequences of the current virulent NDV fusion protein cleavage site motif revealed 112RRQKR↓F117, unlike the locally used avirulent vaccine strains (112GRQGR↓L117). The epidemiological data, MDT results, cleavage site sequence, and phylogenetic analysis all indicated that the present NDV isolates were virulent. The four NDV sequences were deposited in GenBank with accession numbers F gene (PP726912-15) and M gene (PP726916-19). The genetic difference between avirulent vaccine strains and circulating virulent NDV could explain the low level of protection provided by locally used vaccines. Further studies are needed to better understand the circulating NDV genotypes in different production systems.

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 multi-species, multi-pathogen avian viral disease outbreak event: Investigating potential for virus transmission at the wild bird – poultry interface

ABSTRACT A free-range organic broiler (Gallus gallus domesticus) premises in Staffordshire was infected by high pathogenicity avian influenza virus (HPAIV) H5N8 during the 2020–2021 epizootic in the United Kingdom (UK). Following initial confirmation of the infection in poultry, multiple wild bird species were seen scavenging on chicken carcasses. Detected dead wild birds were subsequently demonstrated to have been infected and succumbed to HPAIV H5N8. Initially, scavenging species, magpie (Pica pica) and raven (Corvus corax) were found dead on the premises but over the following days, buzzards (Buteo buteo) were also found dead within the local area with positive detection of HPAIV in submitted carcasses. The subacute nature of microscopic lesions within a buzzard was consistent with the timeframe of infection. Finally, a considerable number of free-living pheasants (Phasianus colchicus) were also found dead in the surrounding area, with carcasses having higher viral antigen loads compared to infected chickens. Limited virus dissemination was observed in the carcasses of the magpie, raven, and buzzard. Further, an avirulent avian paramyxovirus type 1 (APMV-1) was detected within poultry samples as well as in the viscera of a magpie infected with HPAIV. Immunohistochemistry did not reveal colocalization of avian paramyxovirus antigens with lesions, supporting an avirulent APMV-1 infection. Overall, this case highlights scenarios in which bi-directional transmission of avian viral diseases between commercial and wild bird species may occur. It also underlines the importance of bio separation and reduced access when infection pressure from HPAIV is high.

Genetic Characterization, Pathogenicity, and Epidemiology Analysis of Three Sub-Genotype Pigeon Newcastle Disease Virus Strains in China.

Pigeon Newcastle disease (ND) is a serious infectious illness caused by the pigeon Newcastle disease virus (NDV) or Paramyxovirus type 1 (PPMV-1). Genotype VI NDV is a primary factor in ND among Columbiformes (such as pigeons and doves). In a recent study, eight pigeon NDV strains were discovered in various provinces in China. These viruses exhibited mesogenic characteristics based on their MDT and ICPI values. The complete genome sequences of these eight strains showed a 90.40% to 99.19% identity match with reference strains of genotype VI, and a 77.86% to 80.45% identity match with the genotype II vaccine strain. Additionally, analysis of the F gene sequence revealed that these NDV strains were closely associated with sub-genotypes VI.2.2.2, VI.2.1.1.2.1, and VI.2.1.1.2.2. The amino acid sequence at the cleavage site of the F protein indicated virulent characteristics, with the sequences 112KRQKRF117 and 112RRQKRF117 observed. Pigeons infected with these sub-genotype strains had a low survival rate of only 20% to 30%, along with lesions in multiple tissues, highlighting the strong spread and high pathogenicity of these pigeon NDV strains. Molecular epidemiology data from the GenBank database revealed that sub-genotype VI.2.1.1.2.2 strains have been prevalent since 2011. In summary, the findings demonstrate that the prevalence of genotype VI NDV is due to strains from diverse sub-genotypes, with the sub-genotype VI.2.1.1.2.2 strain emerging as the current epidemic strain, highlighting the significance of monitoring pigeon NDV in China.

Newcastle Disease - overview and analysis of the current spread of the disease in Bulgaria and Europe

Newcastle disease (ND) is a highly contagious and severe worldwide disease affecting birds. The infection is a mild zoonosis and can cause conjunctivitis in humans, but the condition is usually mild and self-limiting. ND is caused by virulent strains of avian paramyxovirus type 1. The disease occurs in five forms: velogenic viscerotrophic, velogenic neutrotropic, mesogenic, lentogenic Newcastle disease and asymptomatic enteric Newcastle disease. Lentogenic strains are very widespread, but are usually asymptomatic and do not cause outbreaks in poultry. Newcastle disease in its highly pathogenic form, is a WOAH listed disease and must be reported. It usually manifests as severe respiratory disease, depression, nervousness and/or diarrhea. The clinical picture is very similar to bird flu, so laboratory tests are important to confirm the diagnosis.

The TRK-fused gene negatively regulates interferon signaling by inhibiting TBK1 phosphorylation during PPMV-1 infection

TRK-fused gene (TFG, tropomyosin-receptor kinase fused gene) is known to negatively regulate the retinoic acid inducible gene (RIG)-I-like receptor (RLR)-mediated interferon (IFN)-I pathway in human cells, thereby participating in the paramyxovirus infection process. We showed that pigeon paramyxovirus type 1 (PPMV-1) infection significantly upregulates TFG expression in infected cells at an early stage. We speculated that PPMV-1 would inhibit IFN activation by upregulating a negative regulator of the IFN pathway. This hypothesis was proved when TFG protein expression was knocked down by RNAi and the replication level of PPMV-1 virus decreased, which indicated that TFG upregulation in the early infection stage benefit virus replication. We next used the IFN-β promoter reporter system to evaluate the role of the TFG in the IFN pathway. The results showed that the TFG inhibited the IFN-β expression stimulated by RIG-I, MAVS (mitochondrial antiviral signaling protein) and TANK-binding kinase 1 (TBK1), but did not inhibit IFN-β activated by the interferon regulatory transcription factor 3 (IRF3), indicating that TFG may affect the function of TBK1, which play an important role in phosphorylation of the IRF3. Further experiments showed that the TFG inhibited the phosphorylation of TBK1, resulting in IRF3 being unable to be phosphorylated. Subsequent experiments on IFN pathway activation confirmed that the IRF3 phosphorylation level was significantly downregulated after overexpression of TFG, while the IFN-β promoter reporting experiment showed that TFG did not directly inhibit the IFN response activated by IRF3. This confirmed that TFG protein negatively regulates the IFN-β pathway by inhibiting TBK1 phosphorylation.

Isolation and Biological Characterization of Newcastle Disease Virus (NDV) Field Isolate Pigeon (Columba livia) from Live Bird Market, East Java in 2019

Background: Avian Paramyxovirus (APMV) type-1 is the leading cause of Newcastle Disease (ND) and taxonomically belongs to the family Paramyxoviridae, genus Avulavirus. Due to its high transmission rate, Newcastle Disease (ND) is included in the A list by the OIE. Purpose: To determine the biological characterize the Newcastle Disease Virus (NDV) field isolate of pigeons (Columba livia) using Mean Death Time (MDT), Intracerebral Pathogenicity Index (ICPI), and Intravenous Pathogenicity Index (IVPI). Methods: Twenty pigeon organ samples were obtained from bird markets in East Java, and one was used as a positive control (LaSota). Organs were isolated from embryonated chicken eggs, identified by the HA test, and then confirmed by the HI test. Furthermore, positive samples were tested for MDT with a 10-1-10-18 dilution (0.1 ml and observed for eight days. The ICPI test used a fresh NDV suspension (0.05 ml and was observed for eight days. The IVPI test used a dose of 0.1 ml and was observed for ten days. Result: The MDT values of isolates MB1/NDV/19, MB2/NDV/19, MB3/NDV/19, and MG1/NDV/19 were 91.2 hours, 112.8 hours, 110.4 hours, and 124,8 hours. The ICPI values of isolate MB1/NDV/19 was 0.2375, MB2/NDV/19 was 0.375, MB3/NDV/19 was 0.5375, and MG1/NDV/19 was 0.3. The IVPI value of isolate MB1/NDV/19 was 0, MB2/NDV/19 was 0, MB3/NDV/19 was 0, and MG1/NDV/19 was 0. Conclusion: All four field samples were positive for NDV as a lentogenic strain based on the MDT, ICPI, and IVPI tests.

A novel array of real-time RT-PCR assays for the rapid pathotyping of type I avian paramyxovirus (APMV-1)

Newcastle disease (ND) caused by virulent avian paramyxovirus type I (APMV-1) is a WOAH and EU listed disease affecting poultry worldwide. ND exhibits different clinical manifestations that may either be neurological, respiratory and/or gastrointestinal, accompanied by high mortality. In contrast, mild or subclinical forms are generally caused by lentogenic APMV-1 and are not subject to notification. The rapid discrimination of virulent and avirulent viruses is paramount to limit the spread of virulent APMV-1. The appropriateness of molecular methods for APMV-1 pathotyping is often hampered by the high genetic variability of these viruses that affects sensitivity and inclusivity. This work presents a new array of real-time RT-PCR (RT-qPCR) assays that enable the identification of virulent and avirulent viruses in dual mode, i.e., through pathotype-specific probes and subsequent Sanger sequencing of the amplification product. Validation was performed according to the WOAH recommendations. Performance indicators on sensitivity, specificity, repeatability and reproducibility yielded favourable results. Reproducibility highlighted the need for assays optimization whenever major changes are made to the procedure. Overall, the new RT-qPCRs showed its ability to detect and pathotype all tested APMV-1 genotypes and its suitability for routine use in clinical samples.

Rapid detection of pigeon Megrivirus using TaqMan real-time PCR technology

Megriviruses have been identified from fecal samples in wild pigeons in Hong Kong (China) and Hungary. In this study, the genomic sequences of pigeon Megriviruses (PiMeVs) were downloaded from GenBank and compared. Based on the genetic comparison results, a pair of primers and TaqMan probe were designed based on the conserved sequences of the 3C gene (located in the P3 gene coding region), and a TaqMan real-time PCR method (TaqMan-qPCR) was established. The standard curve of the TaqMan-qPCR had an axial intercept of 39.74 and a slope of -3.2475 with a linear correlation (R2) of 1.00 and an efficiency of 103.2%. No cross-amplification signal was found from other pigeon viruses (such as avian influenza virus, pigeon paramyxovirus type I, pigeon torque teno virus, pigeon adenovirus, and pigeon circovirus). The limit of detection concentration was 53.6 copies/μL. The intra- and interassay results were less than 1.0% based on the reproducibility test. Furthermore, field samples investigation by the established TaqMan-qPCR method showed that positive signals can be found from racing pigeon fecal samples and embryos. Thus, our data suggested that this visible TaqMan-qPCR method is sensitive, specific, and reproducible. Moreover, we first confirmed the presence of pigeon Megrivirus infection in racing pigeon embryos, indicating that the virus may be vertically transmitted. This study provides a reference basis for further understanding the epidemiology of PiMeVs.

Genomic and biological characterization of Pigeon Paramyxovirus Type-1 isolated from Indian pigeons: First report on the six nucleotide insertion in the non-coding region of nucleoprotein gene

Genotypic analysis of Pigeon Paramyxovirus Type-1 (PPMV-1) virus, in corroboration with pathotyping, underpins the knowledge on the occurrence of PPMV-1 mediated Newcastle disease in poultry. In the present study, two PPMV-1 isolates, namely D167 and D168, obtained from feral pigeons of India in the year 2014 were analysed for their genotypic and pathotypic characteristics. Phylogenetic analysis of Fusion (F) gene grouped D167 and D168 under sub-genotypes VI.2.2.2. and VI.2.1.1.2.2. respectively. The separate positioning of these isolates within genotype VI is corroborated with the variation in restriction enzyme sites analysed through virtual restriction mapping. Analysis of FPCS region showed that both D167 and D168 possessed 112RRQKRF117 amino-acid pattern. Intra-cerebral pathogenicity index (ICPI) of D167 and D168 was 1.57 and 1.3, and mean death time (MDT) was 48 and 70 hrs respectively, designating D168 as a mesogenic pathotype, and D167 as a velogenic pathotype. Histopathological analysis of proventriculus, intestine, lungs and spleen of chickens infected with D167 and D168 isolates through intramuscular (I/M), subcutaneous (S/C) and oculo-nasal/oral (O/N) routes of inoculation showed similar severity of tissue damage. This study shows that PPMV-1 isolates belonging to two different sub-genotypes without a common ancestor, can occur together in a particular geographical region. It also shows that PPMV-1 gains virulence in chickens, which needs to be addressed in order to avoid emergence of PPMV-1 as new velogenic variant causing Newcastle disease in chickens.

Biological characterization of isolated pigeon Paramyxovirus-1 and its pathogenicity analysis in SPF chickens

Pigeon paramyxovirus type 1 (PPMV-1) is considered as an antigenic variant of Newcastle Disease leading to high mortality and significant economic losses to the poultry industry. However, the pathogenicity of PPMV-1 to chickens is still unclear. Herein, we reported the biological characterization of the isolated PPMV-1 from the diseased pigeons suspected to Newcastle Disease and studied its pathogenicity in SPF chickens. The phylogenetic tree and evolution distances revealed that the new isolate belonged to a VI.2.1.1.2.2 sub-genotype of NDV. Despite the cleavage motif of the F protein containing the 112RRQKR↓F117 sequence associated with virulent NDV strains, and the value of MDT and ICPI of the isolate showing mesogenic characteristics, the challenge trial showed that the isolate had weak pathogenicity to chickens while causing lesions in multiple tissues and organs in pigeons.

Newcastle disease in pigeon review article

Newcastle disease (ND) is a viral disease of poultry and other bird species like pigeon (Columbi livia), it characterizes as devastating and contagious and it has been distributed worldwide. ND in pigeons is caused by pigeon paramyxovirus type 1(PPMV-1) which is an antigenic and host variant of the avian paramyxovirus serotype 1 (APMV-1), the disease in pigeons is termed paramyxovirosis and cause nervous signs with high mortality usually in the bird with kidneys infected with viscerotropic strains, and neural signs appeared individually. PPMV-1 was initially detected by hemagglutination activity (HA) and confirmed with hemagglutination inhibition assay (HI), and molecular-based techniques. Serological diagnosis of paramyxovirosis is necessary because of the similarity of the PPMV-1 infection with sodium chloride poisoning, pigeon herpes virus infection (PHV), and ornidazole overdose that cause same neurological signs. PPMV-1 infection can be controlled effectively by vaccination by specific vaccines associated with good biosecurity aspect

Spread of Pathogens Causing Respiratory Viral Diseases Before and During CoVID-19 Pandemic in Kazakhstan.

Analyze clinical samples collected and determine the etiology of viral pathogens and the dynamics of their spread. Acute respiratory viral infections remain one of the key health problems worldwide. They constitute etiologically independent diseases, with similar clinical infection manifestations and a single mechanism for the transmission of pathogens. 4712 nasopharyngeal swabs were collected from people before and during the COVID-19 pandemic with acute respiratory infections that tested negative for COVID-19 and were examined in this study. The collected samples were screened by a real-time polymerase chain reaction on a Rotor-Gene Q6 plex instrument. Statistical processing of the results, tabular, and graphical data were analyzed in the MS Excel. The largest number of the nasopharyngeal swabs were collected from children under 17years of age (60.75%). In 702 samples (9.85%) pathogens of respiratory infections of non-influenza etiology were detected, including adenovirus, bocavirus, coronavirus, metapneumovirus, paramyxovirus types I-IV, respiratory syncytial virus, and rhinovirus. At the same time, both before and during the COVID-19 pandemic, different influenza virus variants co-circulation (A/H1N1, A/H3N2, and type B) were discovered, with a predominance of viruses with the antigenic formula A/H1N1. The results of the study indicate the need for continuous monitoring of the viral pathogens spread, which will expand the existing knowledge of the viral etiology of respiratory diseases and highlight the importance of viruses in the respiratory infections occurrence.

Genomic and comparative clinico-pathological assessment of two Pakistani pigeon-derived newcastle disease virus sub-genotypes XXI.1.1 and XXI.1.2 isolated in 2017

Pigeon paramyxovirus type-1 (PPMV-1) is an antigenic-variant of Newcastle disease virus (NDV) which is associated with infection in Columbidae family. In this study, we isolated two pigeon-derived strains pi/Pak/Lhr/SA_1/17 (designed as SA_1) and pi/Pak/Lhr/SA_2/17 (designed as SA_2) from diseased pigeons collected in Punjab province in 2017. We performed the whole genome, phylogenetic analysis and comparative clinico-pathological evaluation of two viruses in pigeons. Phylogenetic analysis based on fusion (F) gene and complete genome sequences showed that SA_1 belonged to sub-genotype XXI.1.1 and SA_2 clustered in sub-genotype XXI.1.2. SA_1 and SA_2 viruses contributed to morbidity and mortality in pigeons. Remarkably, although the two viruses resulted in comparatively similar pattern of pathogenesis and replication ability in various tissues of infected pigeons, SA_2 could cause more severe histopathological lesions and had comparatively high replication ability in pigeons than SA_1. Moreover, pigeons infected with SA_2 had higher shedding efficiency than that of pigeons infected with SA_1. Moreover, several aa substitutions in the major functional domains of the F and HN proteins might be contributed to the pathogenic differences between the two isolates in pigeons. Overall, these findings provide us with important insight into the epidemiology and evolution of PPMV-1 in Pakistan and laid the foundation for the further elucidation of the mechanism underlying the pathogenic difference of PPMV-1 in pigeons.

Molecular and retrospective analysis of pigeon paramyxovirus type 1 infections in confinement-reared pigeons (Columbia livia); 2010–2020

Molecular and retrospective analysis of pigeon paramyxovirus type 1 infections in confinement-reared pigeons (Columbia livia); 2010–2020

The brain-specific upregulation of CARD11 in response to avian brain-neurotropic virus infection serves as a potential biomarker

Avian neurotropic viruses are critical problems in poultry industry causing severe central nervous system (CNS) damage with neuroinvasive and neurovirulence properties. Biomarker of neurotropic viral intracranial invasion is of great application value for the diagnosis, but that of avian neurotropic viruses remains elusive. Previously, we found that chicken caspase recruitment domain family, member 11 (CARD11) was only upregulated in virulent Newcastle disease virus-infected chickens and in chicken primary neuronal cells. In this study, CARD11 was systemically expressed in chickens and pigeons detected by absolute qPCR and immunohistochemical (IHC) assay. After virus challenging, only avian neurotropic viruses (avian encephalomyelitis virus [AEV] and pigeon paramyxovirus type 1 [PPMV-1]) except Marek's disease virus (MDV) can invade brain and cause pathological changes. The relative mRNA expression of CARD11 was brain-upregulated in AEV- or PPMV-1-infected animals, rather than MDV and non-neurotropic viruses (fowl adenovirus serotype 4 [FAdV-4] and infectious bronchitis virus [IBV]). Similarly, the protein expression of CARD11 was only upregulated in the cerebra and cerebella infected by avian brain-neurotropic virus using IHC assay. And there were no correlations between the change level of CARD11 and viral load. Our preliminary data suggested that avian CARD11 may be a potential brain biomarker for avian brain-neurotropic virus invasion.

Understanding the disease and economic impact of avirulent avian paramyxovirus type 1 (APMV-1) infection in Great Britain.

Newcastle disease (ND) is a notifiable disease affecting chickens and other avian species caused by virulent strains of Avian paramyxovirus type 1 (APMV-1). While outbreaks of ND can have devastating consequences, avirulent strains of APMV-1 generally cause subclinical infections or mild disease. However, viruses can cause different levels of disease in different species and virulence can evolve following cross-species transmission events. This report describes the detection of three cases of avirulent APMV-1 infection in Great Britain (GB). Case 1 emerged from the 'testing to exclude' scheme in chickens in Shropshire while cases 2 and 3 were made directly from notifiable avian disease investigations in chicken broilers in Herefordshire and on premises in Wiltshire containing ducks and mixed species, respectively). Class II/genotype I.1.1 APMV-1 from case 1 shared 99.94% identity to the Queensland V4 strain of APMV-1. Class II/genotype II APMV-1 was detected from case 2 while the class II/genotype I.2 virus from case 3 aligned closely with strains isolated from Anseriformes. Exclusion of ND through rapid detection of avirulent APMV-1 is important where clinical signs caused by avirulent or virulent APMV-1s could be ambiguous. Understanding the diversity of APMV-1s circulating in GB is critical to understanding disease threat from these adaptable viruses.