Virome release of an invasive exotic plant species in southern France.

The increase in human-mediated introduction of plant species to new regions has resulted in a rise of invasive exotic plant species (IEPS) that has had significant effects on biodiversity and ecosystem processes. One commonly accepted mechanism of invasions is that proposed by the enemy release hypothesis (ERH), which states that IEPS free from their native herbivores and natural enemies in new environments can outcompete indigenous species and become invasive. We here propose the virome release hypothesis (VRH) as a virus-centered variant of the conventional ERH that is only focused on enemies. The VRH predicts that vertically transmitted plant-associated viruses (PAV, encompassing phytoviruses and mycoviruses) should be co-introduced during the dissemination of the IEPS, while horizontally transmitted PAV of IEPS should be left behind or should not be locally transmitted in the introduced area due to a maladaptation of local vectors. To document the VRH, virome richness and composition as well as PAV prevalence, co-infection, host range, and transmission modes were compared between indigenous plant species and an invasive grass, cane bluestem (Bothriochloa barbinodis), in both its introduced range (southern France) and one area of its native range (Sonoran Desert, Arizona, USA). Contrary to the VRH, we show that invasive populations of B. barbinodis in France were not associated with a lower PAV prevalence or richness than native populations of B. barbinodis from the USA. However, comparison of virome compositions and network analyses further revealed more diverse and complex plant-virus interactions in the French ecosystem, with a significant richness of mycoviruses. Setting mycoviruses apart, only one putatively vertically transmitted phytovirus (belonging to the Amalgaviridae family) and one putatively horizontally transmitted phytovirus (belonging to the Geminiviridae family) were identified from B. barbinodis plants in the introduced area. Collectively, these characteristics of the B. barbinodis-associated PAV community in southern France suggest that a virome release phase may have immediately followed the introduction of B. barbinodis to France in the 1960s or 1970s, and that, since then, the invasive populations of this IEPS have already transitioned out of this virome release phase, and have started interacting with several local mycoviruses and a few local plant viruses.

New duck papillomavirus type identified in a mallard in Missouri, USA.

Papillomaviruses are small circular DNA viruses that infect epithelial and mucosal cells and have co-evolved with their hosts. Some papillomaviruses in mammals are well studied (especially those associated with disease). However, there is limited information on papillomaviruses associated with avian hosts. From a cloacal swab sample of a mallard (Anas platyrhynchos) sampled in Missouri, USA (6 Jan 2023), we identified a papillomavirus (7839 nt) that shares ~68% genome-wide nucleotide sequence identity with Anas platyrhynchos papillomavirus 1 (AplaPV1) from a mallard sampled in Newfoundland (Canada) and ~40% with AplaPV2 from a mallard sampled in Minnesota (USA) with mesenchymal dermal tumors. The papillomavirus we identified shares 73.6% nucleotide sequence identity in the L1 gene with that of AplaPV1 and thus represents a new AplaPV type (AplaPV3). The genome sequence of AplaPV3 shares >97% identity with three partial PV genome sequences (1316, 1997, and 4241 nt) identified in a mallard in India, indicating that that virus was also AplaPV3.

Diverse papillomaviruses identified from Antarctic fur seals, leopard seals and Weddell seals from the Antarctic.

Papillomaviruses (family Papillomaviridae) are non-enveloped, circular, double-stranded DNA viruses known to infect squamous and mucosal epithelial cells. In the family Papillomaviridae there are 53 genera and 133 viral species whose members infect a variety of mammalian, avian, reptilian, and fish species. Within the Antarctic context, papillomaviruses (PVs) have been identified in Adélie penguins (Pygoscelis adeliae, 2 PVs), Weddell seals (Leptonychotes weddellii, 7 PVs), and emerald notothen (Trematomus bernacchii, 1 PV) in McMurdo Sound and Ross Island in eastern Antarctica. Here we identified 13 diverse PVs from buccal swabs of Antarctic fur seals (Arctocephalus gazella, 2 PVs) and leopard seal (Hydrurga leptonyx, 3 PVs) in western Antarctica (Antarctic Peninsula), and vaginal and nasal swabs of Weddell seals (8 PVs) in McMurdo Sound. These PV genomes group into four genera representing 11 new papillomavirus types, of which five are from two Antarctic fur seals and a leopard seal and six from Weddell seals.

Sex-specific recruitment rates contribute to male-biased sex ratio in Adélie penguins.

Sex-related differences in vital rates that drive population change reflect the basic life history of a species. However, for visually monomorphic bird species, determining the effect of sex on demographics can be a challenge. In this study, we investigated the effect of sex on apparent survival, recruitment, and breeding propensity in the Adélie penguin (Pygoscelis adeliae), a monochromatic, slightly size dimorphic species with known age, known sex, and known breeding history data collected during 1996-2019 (n = 2127 birds) from three breeding colonies on Ross Island, Antarctica. Using a multistate capture-mark-recapture maximum-likelihood model, we estimated apparent survival (S^), recapture (resighting) probability (p^), and the probability of transitioning among breeding states and moving between colonies (ψ^; colony-specific non-juvenile pre-breeders, breeders, and non-breeders). Survival rate varied by breeding status and colony, but not sex, and pre-breeders had higher survival rates than breeders and non-breeders. Females had a higher probability of recruiting into the breeding population each year and may enter the breeding pool at younger ages. In contrast, both sexes had the same probability of breeding from year to year once they had recruited. Although we detected no direct sex effects on survival, the variation in recruitment probability and age-at-first reproduction, along with lower survival rates of breeders compared to pre-breeders, likely leads to shorter lifespans for females. This is supported by our findings of a male-biased mean adult sex ratio (ASR) of 1.4 males for every female (x^ proportion of males = 0.57, SD = 0.07) across all colonies and years in this metapopulation. Our study illustrates how important it can be to disentangle sex-related variation in population vital rates, particularly for species with complex life histories and demographic dynamics.

Direct detection of canine picornavirus complete coding sequence in wastewater using long-range reverse-transcriptase polymerase chain reaction and long-read sequencing.

We describe four complete coding sequence (cCDS) of canine picornavirus from wastewater in Arizona, USA detected by coupling cCDS single-contig (∼7.5 kb) reverse-transcriptase polymerase chain reaction (RT-PCR) and low-cost long-read high-throughput sequencing. For viruses of medical/veterinary importance, this workflow expands possibilities of wastewater based genomic epidemiology for exploring virus evolutionary dynamics especially in low-resource settings.

Diverse Small Circular DNA Viruses Identified in an American Wigeon Fecal Sample.

American wigeons (Mareca americana) are waterfowls that are widely distributed throughout North America. Research of viruses associated with American wigeons has been limited to orthomyxoviruses, coronaviruses, and circoviruses. To address this poor knowledge of viruses associated with American wigeons, we undertook a pilot study to identify small circular DNA viruses in a fecal sample collected in January 2021 in the city of Tempe, Arizona (USA). We identified 64 diverse circular DNA viral genomes using a viral metagenomic workflow biased towards circular DNA viruses. Of these, 45 belong to the phylum Cressdnaviricota based on their replication-associated protein sequence, with 3 from the Genomoviridae family and the remaining 42 which currently cannot be assigned to any established virus group. It is most likely that these 45 viruses infect various organisms that are associated with their diet or environment. The remaining 19 virus genomes are part of the Microviridae family and likely associated with the gut enterobacteria of American wigeons.

Identification of small circular DNA viruses in coyote fecal samples from Arizona (USA).

Coyotes (Canis latrans) have a broad geographic distribution across North and Central America. Despite their widespread presence in urban environments in the USA, there is limited information regarding viruses associated with coyotes in the USA and in particular the state of Arizona. To explore viruses associated with coyotes, particularly small DNA viruses, 44 scat samples were collected (April-June 2021 and November 2021-January 2022) along the Salt River near Phoenix, Arizona (USA), along 43 transects (500 m). From these samples, we identified 11 viral genomes: two novel circoviruses, six unclassified cressdnaviruses, and two anelloviruses. One of the circoviruses is most closely related to a circovirus sequence identified from an aerosolized dust sample in Arizona, USA. The second circovirus is most closely related to a rodent-associated circovirus and canine circovirus. Of the unclassified cressdnaviruses, three encode replication-associated proteins that are similar to those found in protists (Histomonas meleagridis and Monocercomonoides exilis), implying an evolutionary relationship with or a connection to similar unidentified protist hosts. The two anelloviruses are most closely related to those found in rodents, and this suggests a diet-related identification.

Anelloviridae taxonomy update 2023.

The family Anelloviridae comprises negative single-stranded circular DNA viruses. Within this family, there are 30 established genera. Anelloviruses in the genus Gyrovirus have been identified infecting various avian species, whereas those in the remaining 29 genera have been found primarily infecting various mammal species. We renamed the 146 anellovirus species with binomial species names, as required by the International Committee on Taxonomy of Viruses (ICTV) using a "genus + freeform epithet" format.

Identification of a novel polyomavirus in wild Sonoran Desert rodents of the family Heteromyidae.

Rodents are the largest and most diverse group of mammals. Covering a wide range of structural and functional adaptations, rodents successfully occupy virtually every terrestrial habitat, and they are often found in close association with humans, domestic animals, and wildlife. Although a significant amount of research has focused on rodents' prominence as known reservoirs of zoonotic viruses, there has been less emphasis on the viral ecology of rodents in general. Here, we utilized a viral metagenomics approach to investigate polyomaviruses in wild rodents from the Baja California peninsula, Mexico, using fecal samples. We identified a novel polyomavirus in fecal samples from two rodent species, a spiny pocket mouse (Chaetodipus spinatus) and a Dulzura kangaroo rat (Dipodomys simulans). These two polyomaviruses represent a new species in the genus Betapolyomavirus. Sequences of this polyomavirus cluster phylogenetically with those of other rodent polyomaviruses and two other non-rodent polyomaviruses (WU and KI) that have been identified in the human respiratory tract. Through our continued work on seven species of rodents, we endeavor to explore the viral diversity associated with wild rodents on the Baja California peninsula and expand on current knowledge of rodent viral ecology and evolution.

Characterization of Diverse Anelloviruses, Cressdnaviruses, and Bacteriophages in the Human Oral DNA Virome from North Carolina (USA).

The diversity of viruses identified from the various niches of the human oral cavity-from saliva to dental plaques to the surface of the tongue-has accelerated in the age of metagenomics. This rapid expansion demonstrates that our understanding of oral viral diversity is incomplete, with only a few studies utilizing passive drool collection in conjunction with metagenomic sequencing methods. For this pilot study, we obtained 14 samples from healthy staff members working at the Duke Lemur Center (Durham, NC, USA) to determine the viral diversity that can be identified in passive drool samples from humans. The complete genomes of 3 anelloviruses, 9 cressdnaviruses, 4 Caudoviricetes large bacteriophages, 29 microviruses, and 19 inoviruses were identified in this study using high-throughput sequencing and viral metagenomic workflows. The results presented here expand our understanding of the vertebrate-infecting and microbe-infecting viral diversity of the human oral virome in North Carolina (USA).

Enhanced detection of mpox virus in wastewater using a pre-amplification approach: A pilot study informing population-level monitoring of low-titer pathogens.

A recent outbreak of the mpox virus (MPXV) occurred in non-endemic regions of the world beginning in May 2022. Pathogen surveillance systems faced pressure to quickly establish response protocols, offering an opportunity to employ wastewater-based epidemiology (WBE) for population-level monitoring. The pilot study reported herein aimed to: (i) develop a reliable protocol for MPXV DNA detection in wastewater which would reduce false negative reporting, (ii) test this protocol on wastewater from various regions across the United States, and (iii) conduct a state of the science review of the current literature reporting on experimental methods for MPXV detection using WBE. Twenty-four-hour composite samples of untreated municipal wastewater were collected from the states of New Jersey, Georgia, Illinois, Texas, Arizona, and Washington beginning July 3rd, 2022 through October 16th, 2022 (n = 60). Samples underwent vacuum filtration, DNA extraction from captured solids, MPXV DNA pre-amplification, and qPCR analysis. Of the 60 samples analyzed, a total of eight (13%) tested positive for MPXV in the states of Washington, Texas, New Jersey, and Illinois. The presence of clade IIb MPXV DNA in these samples was confirmed via Sanger sequencing and integration of pre-amplification prior to qPCR decreased the rate of false negative detections by 87% as compared to qPCR analysis alone. Wastewater-derived detections of MPXV were compared to clinical datasets, with 50% of detections occurring as clinical cases were increasing/peaking and 50% occurring as clinical cases waned. Results from the literature review (n = 9 studies) revealed successful strategies for the detection of MPXV DNA in wastewater, however also emphasized a need for further method optimization and standardization. Overall, this work highlights the use of pre-amplification prior to qPCR detection as a means to capture the presence of MPXV DNA in community wastewater and offers guidance for monitoring low-titer pathogens via WBE.

Identification and characterization of a polyomavirus in the thornback skate (Raja clavata).

Members of the family Polyomaviridae have a circular double-stranded DNA genome that have been identified in various hosts ranging from mammals to arachnids. Here we report the identification and analysis of a complete genome sequence of a novel polyomavirus, Raja clavata polyomavirus (RcPyV1), from a cartilaginous fish, the thornback skate (Raja clavata). The genome sequence was determined using a metagenomics approach with an aim to provide baseline viral data in cartilaginous fish in different ecosystems. The RcPyV1 genome (4,195 nucleotides) had typical organization of polyomavirus, including early antigens (small T; Large T) encoded on one strand and late viral proteins (VP1; VP2) on the complementary strand. Maximum-likelihood phylogenetic analysis of the large T-antigen revealed that RcPyV1 clusters with a polyomavirus obtained from another cartilaginous fish, the guitarfish polyomavirus 1 (GfPyV1). These two share ~ 56% pairwise identity in LT and VP1 protein sequences. These analyses support the hypothesis that cartilaginous fishes have a specific lineage of polyomaviruses.

Viral anti-inflammatory serpin reduces immuno-coagulopathic pathology in SARS-CoV-2 mouse models of infection.

SARS-CoV-2 acute respiratory distress syndrome (ARDS) induces uncontrolled lung inflammation and coagulopathy with high mortality. Anti-viral drugs and monoclonal antibodies reduce early COVID-19 severity, but treatments for late-stage immuno-thrombotic syndromes and long COVID are limited. Serine protease inhibitors (SERPINS) regulate activated proteases. The myxoma virus-derived Serp-1 protein is a secreted immunomodulatory serpin that targets activated thrombotic, thrombolytic, and complement proteases as a self-defense strategy to combat clearance. Serp-1 is effective in multiple animal models of inflammatory lung disease and vasculitis. Here, we describe systemic treatment with purified PEGylated Serp-1 as a therapy for immuno-coagulopathic complications during ARDS. Treatment with PEGSerp-1 in two mouse-adapted SARS-CoV-2 models in C57Bl/6 and BALB/c mice reduced lung and heart inflammation, with improved outcomes. PEGSerp-1 significantly reduced M1 macrophages in the lung and heart by modifying urokinase-type plasminogen activator receptor (uPAR), thrombotic proteases, and complement membrane attack complex (MAC). Sequential changes in gene expression for uPAR and serpins (complement and plasminogen inhibitors) were observed. PEGSerp-1 is a highly effective immune-modulator with therapeutic potential for severe viral ARDS, immuno-coagulopathic responses, and Long COVID.

Metagenomics reveals the structure of Mastrevirus-host interaction network within an agro-ecosystem.

As highly pervasive parasites that sometimes cause disease, viruses are likely major components of all natural ecosystems. An important step towards both understanding the precise ecological roles of viruses and determining how natural communities of viral species are assembled and evolve is obtaining full descriptions of viral diversity and distributions at ecosystem scales. Here, we focused on obtaining such 'community-scale' data for viruses in a single genus. We chose the genus Mastrevirus (family Geminiviridae), members of which have predominantly been found infecting uncultivated grasses (family Poaceae) throughout the tropical and sub-tropical regions of the world. We sampled over 3 years, 2,884 individual Poaceae plants belonging to thirty different species within a 2-ha plot which included cultivated and uncultivated areas on the island of Reunion. Mastreviruses were found in ∼8 per cent of the samples, of which 96 per cent did not have any discernible disease symptoms. The multitude of host-virus associations that we uncovered reveals both the plant species that most commonly host mastreviruses and the mastrevirus species (such as maize streak virus and maize streak Reunion virus) that have especially large host ranges. Our findings are consistent with the hypothesis that perennial plant species capable of hosting years-long mixed mastrevirus infections likely play a disproportionately important role in the generation of inter-species and inter-strain mastrevirus recombinants.

Evolution of anelloviruses from a circovirus-like ancestor through gradual augmentation of the jelly-roll capsid protein.

Anelloviruses are highly prevalent in diverse mammals, including humans, but so far have not been linked to any disease and are considered to be part of the 'healthy virome'. These viruses have small circular single-stranded DNA (ssDNA) genomes and encode several proteins with no detectable sequence similarity to proteins of other known viruses. Thus, anelloviruses are the only family of eukaryotic ssDNA viruses currently not included in the realm Monodnaviria. To gain insights into the provenance of these enigmatic viruses, we sequenced more than 250 complete genomes of anelloviruses from nasal and vaginal swab samples of Weddell seal (Leptonychotes weddellii) from Antarctica and a fecal sample of grizzly bear (Ursus arctos horribilis) from the USA and performed a comprehensive family-wide analysis of the signature anellovirus protein ORF1. Using state-of-the-art remote sequence similarity detection approaches and structural modeling with AlphaFold2, we show that ORF1 orthologs from all Anelloviridae genera adopt a jelly-roll fold typical of viral capsid proteins (CPs), establishing an evolutionary link to other eukaryotic ssDNA viruses, specifically, circoviruses. However, unlike CPs of other ssDNA viruses, ORF1 encoded by anelloviruses from different genera display remarkable variation in size, due to insertions into the jelly-roll domain. In particular, the insertion between ß-strands H and I forms a projection domain predicted to face away from the capsid surface and function at the interface of virus-host interactions. Consistent with this prediction and supported by recent experimental evidence, the outermost region of the projection domain is a mutational hotspot, where rapid evolution was likely precipitated by the host immune system. Collectively, our findings further expand the known diversity of anelloviruses and explain how anellovirus ORF1 proteins likely diverged from canonical jelly-roll CPs through gradual augmentation of the projection domain. We suggest assigning Anelloviridae to a new phylum, 'Commensaviricota', and including it into the kingdom Shotokuvirae (realm Monodnaviria), alongside Cressdnaviricota and Cossaviricota.

Using archived and biocollection samples towards deciphering the DNA virus diversity associated with rodent species in the families cricetidae and heteromyidae.

Rodentia is the most speciose order of mammals, and they are known to harbor a wide range of viruses. Although there has been significant research on zoonotic viruses in rodents, research on the diversity of other viruses has been limited, especially for rodents in the families Cricetidae and Heteromyidae. In fecal and liver samples of nine species of rodents, we identify 346 distinct circular DNA viral genomes. Of these, a large portion are circular, single-stranded DNA viruses in the families Anelloviridae (n = 3), Circoviridae (n = 5), Genomoviridae (n = 7), Microviridae (n = 297), Naryaviridae (n = 4), Vilyaviridae (n = 15) and in the phylum Cressdnaviricota (n = 13) that cannot be assigned established families. We also identified two large bacteriophages of 36 and 50 kb that are part of the class Caudoviricetes. Some of these viruses are clearly those that infect rodents, however, most of these likely infect various organisms associated with rodents, their environment or their diet.

Changes to virus taxonomy and the ICTV Statutes ratified by the International Committee on Taxonomy of Viruses (2023).

This article reports changes to virus taxonomy and taxon nomenclature that were approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in April 2023. The entire ICTV membership was invited to vote on 174 taxonomic proposals that had been approved by the ICTV Executive Committee in July 2022, as well as a proposed revision of the ICTV Statutes. All proposals and the revised ICTV Statutes were approved by a majority of the voting membership. Of note, the ICTV continued the process of renaming existing species in accordance with the recently mandated binomial format and included gene transfer agents (GTAs) in the classification framework by classifying them as viriforms. In total, one class, seven orders, 31 families, 214 genera, and 858 species were created.