Whole-genome based strain identification of fowlpox virus directly from cutaneous tissue and propagated virus

Parapoxvirus species revisited by whole genome sequencing: A retrospective analysis of bovine virus isolates

Parapoxviruses (PPV) of animals are spread worldwide. While the Orf virus (ORFV) species is a molecularly well-characterized prototype pathogen of small ruminants, the genomes of virus species affecting large ruminants, namely Bovine papular stomatitis virus (BPSV) and Pseudocowpox virus (PCPV), are less well known. Using Nanopore sequencing we retrospectively show the whole genome sequences (WGS) of six BPSV, three PCPV isolates and an attenuated ORFV strain, originating from different geographic locations. A phylogenetic tree shows that the de novo assembled genomes belong to PPV species including WGS of reference PPV. Remarkably, Nanopore sequencing allowed the molecular resolution of inverted terminal repeats (ITR) and the hairpin loop within the de novo assembled WGS. Additionally, peculiarities regarding map location of two genes and the heterogeneity of a genomic region were noted. Details for the molecular variability of an interferon response modulatory gene (ORF116) and the PCPV specificity of gene 073.5 are reported. In summary, WGS gained by Nanopore sequencing allowed analysis of complete PPV genomes and confident virus species attribution within a phylogenetic tree avoiding uncertainty of limited gene-based diagnostics. Nanopore-based WGS provides robust comparison of PPV genomes and reliable identity determination of new Poxviruses.

Snapshot of the Phylogenetic Relationships among Avian Poxviruses Circulating in Portugal between 2017 and 2023

Avipoxvirus (APV), a linear dsDNA virus belonging to the subfamily Chordopoxvirinae of the family Poxviridae, infects more than 278 species of domestic and wild birds. It is responsible for causing avian pox disease, characterized by its cutaneous and diphtheric forms. With a high transmission capacity, it can cause high economic losses and damage to the ecosystem. Several diagnostic methods are available, and bird vaccination can be an effective preventive measure. Ten APV-positive samples were analyzed to update the molecular characterization and phylogenetic analysis of viruses isolated in Portugal between 2017 and 2023. A P4b gene fragment was amplified using a PCR, and the nucleotide sequence of the amplicons was determined using Sanger sequencing. The sequences obtained were aligned using ClustalW, and a maximum likelihood phylogenetic tree was constructed. With this study, it was possible to verify that the analyzed sequences are distributed in subclades A1, A2, B1, and B3. Since some of them are quite similar to others from different countries and obtained in different years, it is possible to conclude that there have been several viral introductions in Portugal. Finally, it was possible to successfully update the data on Avipoxviruses in Portugal.

Phylogenetic landscape of Monkeypox Virus (MPV) during the early outbreak in New York City, 2022

Monkeypox (MPOX) is a zoonotic disease endemic to regions of Central/Western Africa. The geographic endemicity of MPV has expanded, broadening the human-monkeypox virus interface and its potential for spillover. Since May 2022, a large multi-country MPV outbreak with no proven links to endemic countries has originated in Europe and has rapidly expanded around the globe, setting off genomic surveillance efforts. Here, we conducted a genomic analysis of 23 MPV-infected patients from New York City during the early outbreak, assessing the phylogenetic relationship of these strains against publicly available MPV genomes. Additionally, we compared the genomic sequences of clinical isolates versus culture-passaged samples from a subset of samples. Phylogenetic analysis revealed that MPV genomes included in this study cluster within the B.1 lineage (Clade IIb), with some of the samples displaying further differentiation into five different sub-lineages of B.1. Mutational analysis revealed 55 non-synonymous polymorphisms throughout the genome, with some of these mutations located in critical regions required for viral multiplication, structural and assembly functions, as well as the target region for antiviral treatment. In addition, we identified a large majority of polymorphisms associated with GA > AA and TC > TT nucleotide replacements, suggesting the action of human APOBEC3 enzyme. A comparison between clinical isolates and cell culture-passaged samples failed to reveal any difference. Our results provide a first glance at the mutational landscape of early MPV-2022 (B.1) circulating strains in NYC.

A novel pathogenic avipoxvirus infecting oriental turtle dove (Streptopelia orientalis) in China shows a high genomic and evolutionary proximity with the pigeon avipoxviruses isolated globally

Avipoxviruses are considered as significant viral pathogen infecting a wide range of domestic and wild bird species globally, yet the majority of avipoxviruses that infect the wild bird species remain uncharacterized and their genetic diversities remain unclear. In this study, we present a novel pathogenic avipoxvirus isolated from the cutaneous pox lesions of a wild oriental turtle dove (Streptopelia orientalis), tentatively named as turtle dovepox virus (TDPV). The avipoxvirus was isolated by using the chorioallantoic membranes of specific pathogen-free chicken embryos which showed characteristic focal pock lesions, followed by cytopathic effects in host cells infected with oriental turtle dovepox virus. An effort in sequencing the whole genome of the poxvirus using next-generation sequencing was given, and the first whole genome sequence of TDPV was obtained. The TDPV genome was 281,386 bp in length and contained 380 predicted open reading frames (ORFs). While 336 of the predicted ORFs showed homology to other characterized avipoxviruses, the other 44 ORFs were unique. Subsequent phylogenetic analyses showed that the novel TDPV shared the closest genetic evolutionary linkage with the avipoxviruses isolated from pigeon in South Africa and India, of which the TDPV genome had the highest sequence similarity (92.5%) with South African pigeonpox virus (FeP2). In conclusion, the sequenced TDPV is significantly different from any other avipoxviruses isolated from avian or other natural host species considering genomic architecture and observed sequence similarity index. Thus, it likely should be considered a separate species. IMPORTANCE Over the past few decades, avipoxviruses have been found in a number of wild bird species including the oriental turtle dove. However, there is no whole genome sequence information on avipoxviruses isolated from oriental turtle dove, leaving us unclear about the evolutionary linkage of avipoxviruses in oriental turtle dove and other wild bird species. Thus, we believe that our study makes a significant contribution because it is the first report of the whole genome sequence of TDPV isolated from a wild oriental turtle dove, which enriches the genomic information of the genus Avipoxvirus, furthermore, contributes to tracking the genetic evolution of avipoxviruses-infected oriental turtle dove species.

Complete genome analysis of African swine fever virus genotypes II, IX and XV from domestic pigs in Tanzania

African swine fever (ASF) caused by ASF virus (ASFV) is an infectious transboundary animal disease notifiable to the World Organization for Animal Health causing high mortality in domestic pigs and wild boars threatening the global domestic pig industry. To date, twenty-four ASFV genotypes have been described and currently genotypes II, IX, X, XV and XVI are known to be circulating in Tanzania. Despite the endemic status of ASF in Tanzania, only one complete genome of ASFV from the country has been described. This study describes the first complete genome sequence of ASFV genotype XV. In addition, the first Tanzanian complete genome of ASFV genotype IX and three ASFV strains belonging to genotype II collected during ASF outbreaks in domestic pigs in Tanzania were determined in this study using Illumina sequencing and comparative genomics analysis. The generated ASFV complete genome sequences ranged from 171,004 to 184,521 base pairs in length with an average GC content of 38.53% and encoded 152 to 187 open reading frames. The results of this study provide insights into the genomic structure of ASFV and can be used to monitor changes within the ASFV genome and improve our understanding of ASF transmission dynamics.

A Novel Pathogenic Avipoxvirus Infecting Vulnerable Cook's Petrel (Pterodroma cookii) in Australia Demonstrates a High Genomic and Evolutionary Proximity with South African Avipoxviruses

Avipoxviruses are assumed to be restricted to avian hosts and are considered to be important viral pathogens that may impact the conservation of many vulnerable or endangered birds. Recent reports of avipoxvirus-like viruses from reptiles suggest that cross-species transmission may be possible within birds and other species. Most of the avipoxviruses in wild and sea birds remain uncharacterized, and their genetic variability is unclear. Here, cutaneous pox lesions were used to recover a novel, full-length Cook's petrelpox virus (CPPV) genome from a vulnerable Cook's petrel (Pterodroma cookii), and this was followed by the detection of immature virions using transmission electron microscopy (TEM). The CPPV genome was 314,065 bp in length and contained 357 predicted open-reading frames (ORFs). While 323 of the ORFs of the CPPV genome had the greatest similarity with the gene products of other avipoxviruses, a further 34 ORFs were novel. Subsequent phylogenetic analyses showed that the CPPV was most closely related to other avipoxviruses that were isolated mostly from South African bird species and demonstrated the highest sequence similarity with a recently isolated flamingopox virus (88.9%) in South Africa. Considering the sequence similarity observed between CPPV and other avipoxviruses, TEM evidence of poxvirus particles, and phylogenetic position, this study concluded that CPPV is a distinct candidate of avipoxviruses. IMPORTANCE Emerging viral disease is a significant concern with potential consequences for human, animal, and environmental health. Over the past several decades, multiple novel viruses have been found in wildlife species, including birds, and they can pose a threat to vulnerable and endangered species. Cook's petrel is currently listed as vulnerable. The threats to the species vary, but are, to a large degree, due to anthropogenic impacts, such as climate change, habitat loss, pollution, and other disturbances by humans. Knowledge of viral pathogens, including poxvirus of Cook's petrel is currently virtually nonexistent.

Genetic Diversity of Fowlpox Virus and Putative Genes Involved in Its Pathogenicity

To determine the genomic variations of fowlpox virus (FPV)-the largest, very ancient, and still harmful avian virus-the complete genomes of 21 FPVs were analyzed. The genomes showed low genetic diversity relative to their overall size. Our studies revealed that FPVs could phylogenetically be divided into two clades, based on their regional distribution, and comparative analysis showed that 40 putative proteins of FPV were associated with geographic differences in viruses, viral pathogenicity, or the onset of diphtheritic lesions. The strain, classified into a subgroup different from others in the genomic analysis, showed relatively low pathogenicity in chickens, and the onset of diphtheritic lesions was observed to be caused only by the specific strain. Despite genetic differences, some commercial vaccines are protective against virulent strains, and intact reticuloendotheliosis virus inserted into field FPV strains was activated but there was no enhancement of the pathogenicity of FPV. These findings will expand our knowledge of the viral proteome and help us understand the pathogenicity of FPV. IMPORTANCE This study aims at determining molecular candidates using comparative genomics to differentiate between the diphtheritic and cutaneous forms of FPV infection, in addition to their association with the pathogenicity of the virus. Full-genomic analyses of multiple fowlpox strains, including field viruses, isolated between 1960s and 2019, and vaccine strains showed the genetic diversity due to regional differences. Comparative genomic analysis offered the clues related to viral virulence. We believe that our study makes a significant contribution to the literature because we are the first to perform such an elaborate study that compares 21 FPVs to study and highlight their diversity, despite the high level of homology between them. Our results shall help provide insights for tackling FPV that has been taking a toll on the poultry for years now.

Molecular characterisation of a novel pathogenic avipoxvirus from an Australian little crow (Corvus bennetti) directly from the clinical sample

Avipoxviruses are thought to be restricted to avian hosts and considered significant pathogens that may impact the conservation of many birds. However, reports of avipoxvirus-like viruses from reptiles suggest that cross-species transmission, within birds and other species, may be possible. The vast majority of avipoxviruses in wild birds remain uncharacterised and their genetic variability is unclear. Here, cutaneous pox lesions were used to recover a novel full-length crowpox virus genome from an Australian little crow (Corvus bennetti), followed by the detection of immature and intracellular mature virions using electron microscopy. The CRPV genome was 328,768 bp in length and contained 403 predicted open-reading frames. While 356 of the ORFs of CRPV genome had the greatest similarity with other avipoxviruses gene products, a further 47 ORFs were novel. Subsequent phylogenetic analyses showed that the CRPV was most closely related to other avipoxviruses isolated from passerine and marine bird species and demonstrated the highest sequence similarity with an albatrosspox virus (84.4%). Considering the sequence similarity observed between CRPV and other avipoxviruses and phylogenetic position, this study concluded that the CRPV to be a distinct available candidate of avipoxviruses.