Evolution, genetic recombination, and phylogeography of goose parvovirus

Comparative pathogenicity of goose parvovirus across different epidemic lineages in ducklings and goslings

The endemic status of goose parvovirus (GPV) continues to devastate the poultry industry in China. Novel GPV (NGPV) and Mutated GPV (MGPV) represent the predominant lineages. However, the comparative pathogenicity between these viruses remains poorly understood. Herein, we selected representative NGPV and MGPV strains as model viruses to assess their pathogenic potential both in vitro and in vivo. In vitro cellular and embryo assays demonstrated that both NGPV and MGPV were capable of replicating in DEF and GEF cells, leading to pronounced cytopathic effects. However, these viruses exhibited distinct levels of intra-embryonic replication capabilities. Furthermore, we conducted in vivo infection experiments and systematically evaluated the pathogenic differences between NGPV and MGPV by examining various indicators, including growth, clinical signs, gross pathology, skeletal development, viral load, and humoral response in the infected animals. The results showed that both NGPV and MGPV inhibited weight gain in goslings and ducklings, with NGPV exerting a more significant suppressive impact. MGPV induced classical gosling plague pathology in goslings, while NGPV led to short beak and dwarfism syndrome in ducklings, notably disrupting skeletal development. Moreover, MGPV and NGPV exhibited diverse host tropisms, with MGPV being more pathogenic to goslings and NGPV to ducklings. Both viruses elicited specific antibody responses, with MGPV being more effective in goslings and NGPV in ducklings. Additionally, MGPV exhibited stronger humoral response compared to NGPV. These findings enhance our understanding of the pathogenicity of prevalent GPV strains in waterfowl, offering a critical theoretical foundation for devising strategies to prevent GPV infections.

Development of a Multiplex Quantitative Polymerase Chain Reaction Assay for the Detection of Duck Enteritis Virus, Goose Parvovirus, and Muscovy Duck Parvovirus

Duck enteritis virus (DEV), goose parvovirus (GPV), and muscovy duck parvovirus (MDPV) all have similar symptoms after infection, such as severe diarrhea, which seriously affects the healthy development of the waterfowl industry. Hence, it is important to devise a rapid and precise assay for the detection of these three viruses. In this study, a TaqMan probe-based multi-quantitative polymerase chain reaction (qPCR) assay was developed and optimized. Three specific primers and probes were designed according to the conserved regions of UL6 of DEV, REP of GPV, and VP1 of MDPV, respectively. DEV demonstrated a detection limit of 11.6 copies, GPV detected a limit of 95 copies, and MDPV showcased a detection limit of 14.8 copies. The correlation coefficient is greater than 0.99, and the amplification efficiency is 89% to 93%. These results indicate that the multiplex qPCR assay has high sensitivity, specificity, and stability. Of the 215 clinical samples used in this study, 33 tested DEV positive, 25 tested GPV positive, and 24 tested MDPV positive. Overall, the assay established in the current study presents a rapid, efficient, specific, and sensitive tool for of detecting DEV, GPV, and MDPV.

Isolation, identification, whole genome sequence analysis, and pathogenicity of a potential recombinant goose parvovirus

Goose parvovirus (GPV) is the etiological agent responsible for gosling plague (GP), which is an acute hemorrhagic infectious disease affecting geese, posing significant economic challenges to the poultry industry. Furthermore, recent studies have identified that the novel goose parvovirus (NGPV), a recombinant variant of the classic GPV, is responsible for duck short beak dwarfism syndrome, which has significantly affected duck farm. Therefore, the infection and genetic evolution of GPV have attracted widespread attention of researchers in poultry disease. In order to clarify the prevalence and genetic evolution of clinically severe GPV in the Heilongjiang region, this study successfully isolated a strain of GPV HLJ2023 from goose embryos, which results in the mortality rate of 100 % after 5 generations. The electron microscope shows that the virus particles are spherical, with a diameter of approximately 28 nm, and HLJ2023 strain has a total genome length of 5048 nt. SimPlot analysis showed that HLJ2023 strain is closely related to duck parvovirus and NGPV in the VP3 gene region. Recombination analysis showed that the isolated strain is a potential recombinant of the NGPV JS191021 strain and the GMD (Goose parvovirus hosted by Muscovy duck) PT strain. the strong pathogenicity of HLJ2023 strain to goslings. 36 h after the challenge, the goslings were depressed and had a mortality rate up to 100 %. Autopsy revealed intestinal bleeding, thinning of the intestinal wall, and a large amount of fibrous clots and fragments in the intestinal cavity. This study isolated a highly pathogenic potential recombinant GPV, further expanding the genetic evolution and pathogenicity information of avian parvovirus. At the same time, the isolated strain provides a candidate strain for the development of biological products for treating GPV.

Research note: Simultaneous detection of GPV, H5 AIV, and GoAstV via TaqMan probe-based multiplex qPCR

The endemic status of goose parvovirus (GPV), H5 subtype avian influenza virus (AIV), and goose astrovirus (GoAstV) infections continues to devastate the poultry industry in China. Despite this, there exists a notable gap in the application of molecular diagnostic techniques. This investigation described the development of a multiplex qualitative polymerase chain reaction (qPCR) assay capable of concurrently detecting GPV, H5 AIV, and GoAstV, with no cross-reactivity observed with other avian viral pathogens. The assay exhibited a detection threshold of 10 copies/μL for both GPV and GoAstV, and 1 copy/μL for H5 AIV. The intra- and inter-assay coefficients of variation were < 3.0%, signifying high repeatability within and across assay batches. Utilizing this multiplex qPCR assay, a batch of 60 clinical samples was analyzed to assess its practical utility. The detected prevalence rates for GoAstV, GPV, and H5 AIV were 35.0% (21/60), 21.7% (13/60), and 15.0% (9/60), respectively. Concurrent infections were also identified, with rates for GPV + GoAstV, GPV + H5 AIV, GoAstV + H5 AIV, and GPV + GoAstV + H5 AIV being 6.7% (4/60), 3.3% (2/60), 3.3% (2/60), and 3.3% (2/60), respectively. The developed multiplex qPCR assay exhibited a diagnostic concordance rate equivalent to that of traditional PCR techniques. This novel assay serves as a rapid, efficient, specific, and sensitive tool for the detection of prevalent goose viruses, thereby enhancing disease management strategies and epidemiological monitoring efforts.

Development and application of a novel recombinase polymerase amplification-Pyrococcus furiosus argonaute system for rapid detection of goose parvovirus

Rapid and accurate detection of goose parvovirus (GPV) is crucial for controlling outbreaks and mitigating their economic impact on the poultry industry. This study introduces recombinase polymerase amplification combined with the Pyrococcus furiosus argonaute (RPA-PfAgo) system, a novel diagnostic platform designed to address the limitations of traditional GPV detection methods. Capitalizing on the rapid DNA amplification of RPA and stringent nucleic acid cleavage by the PfAgo protein, the RPA-PfAgo system offers high specificity and sensitivity in detecting GPV. Our optimization efforts included primer and probe configurations, reaction parameters, and guided DNA selection, culminating in a detection threshold of 102 GPV DNA copies per microlitre. The specificity of the proposed method was rigorously validated against a spectrum of avian pathogens. Clinical application to lung tissues from GPV-infected geese yielded a detection concordance of 100%, surpassing that of qPCR and PCR in both rapidity and operational simplicity. The RPA-PfAgo system has emerged as a revolutionary diagnostic modality for managing this disease, as it is a promising rapid, economical, and onsite GPV detection method amenable to integration into broad-scale disease surveillance frameworks. Future explorations will extend the applicability of this method to diverse avian diseases and assess its field utility across various epidemiological landscapes.

Molecular and Evolutionary Characteristics of Chicken Parvovirus (ChPV) Genomes Detected in Chickens with Runting-Stunting Syndrome

Chicken Parvovirus (ChPV) belongs to the genus Aveparvovirus and is implicated in enteric diseases like runting-stunting syndrome (RSS) in poultry. In RSS, chicken health is affected by diarrhea, depression, and increased mortality, causing significant economic losses in the poultry industry. This study aimed to characterize the ChPV genomes detected in chickens with RSS through a metagenomic approach and compare the molecular and evolutionary characteristics within the Aveparvovirus galliform1 species. The intestinal content of broiler flocks affected with RSS was submitted to viral metagenomics. The assembled prevalent genomes were identified as ChPV after sequence and phylogenetic analysis, which consistently clustered separately from Turkey Parvovirus (TuPV). The strain USP-574-A presented signs of genomic recombination. The selective pressure analysis indicated that most of the coding genes in A. galliform1 are evolving under diversifying (negative) selection. Protein modeling of ChPV and TuPV viral capsids identified high conservancy over the VP2 region. The prediction of epitopes identified several co-localized antigenic peptides from ChPV and TuPV, especially for T-cell epitopes, highlighting the immunological significance of these sites. However, most of these peptides presented host-specific variability, obeying an adaptive scenario. The results of this study show the evolutionary path of ChPV and TuPV, which are influenced by diversifying events such as genomic recombination and selective pressure, as well as by adaptation processes, and their subsequent immunological impact.

Development and application of quadruplex real time quantitative PCR method for differentiation of Muscovy duck parvovirus, Goose parvovirus, Duck circovirus, and Duck adenovirus 3

Introduction

Muscovy duck parvovirus (MDPV), Goose parvovirus (GPV), Duck circovirus, (DuCV) and Duck adenovirus 3 (DAdV-3) are important pathogens that cause high morbidity and mortality in ducks, causing huge economic loss for the duck industry.

Methods

The present study, a quadruplex one-step real time quantitative PCR method for the detection of MDPV, GPV, DuCV, and DAdV-3 was developed.

Results

The results showed that assay had no cross-reactivity with other poultry pathogens [Duck plague virus (DPV), Duck tembusu virus (DTMUV), H6 avian influenza virus (H6 AIV), New duck reovirus (NDRV), Newcastle disease virus (NDV), H4 avian influenza virus (H4 AIV), Escherichia coli (E. coli), Muscovy duck reovirus (MDRV), Egg drop syndrome virus (EDSV), Pasteurella multocida (P. multocida)]. The sensitivity result showed that the limits of detection for MDPV, GPV, DuCV, and DAdV-3 were 10, 10, 1 and 10 copies/µl, respectively; The coefficients of variation intra- and inter-method was 1-2%; The range of linear (109 to 103 copies/µL) demonstrated the R2 values for MDPV, GPV, DuCV, and DAdV-3 as 0.9975, 0.998, 0.9964, and 0.996, respectively. The quadruplex real time quantitative PCR method efficiency was 90.30%, 101.10%, 90.72%, and 90.57% for MDPV, GPV, DuCV, and DAdV-3, respectively. 396 clinical specimens collected in some duck sausages from June 2022 to July 2023 were simultaneously detected using the established quadruplex real time quantitative PCR method and the reported assays. The detection rates for MDPV, GPV, DuCV, and DAdV-3 were 8.33% (33/396), 17.93% (71/396), 33.58% (133/396), and 29.04% (115/396), respectively. The agreement between these assays was greater than 99.56%.

Discussion

The developed quadruplex real-time quantitative PCR assay can accurately detect these four viruses infecting ducks, providing a rapid, sensitive, specific and accurate technique for clinical testing.