Outbreak Associated with SARS-CoV-2 B.1.617.2 (Delta) Variant in an Elementary School - Marin County, California, May-June 2021.

On May 25, 2021, the Marin County Department of Public Health (MCPH) was notified by an elementary school that on May 23, an unvaccinated teacher had reported receiving a positive test result for SARS-CoV-2, the virus that causes COVID-19. The teacher reported becoming symptomatic on May 19, but continued to work for 2 days before receiving a test on May 21. On occasion during this time, the teacher read aloud unmasked to the class despite school requirements to mask while indoors. Beginning May 23, additional cases of COVID-19 were reported among other staff members, students, parents, and siblings connected to the school. To characterize the outbreak, on May 26, MCPH initiated case investigation and contact tracing that included whole genome sequencing (WGS) of available specimens. A total of 27 cases were identified, including that of the teacher. During May 23-26, among the teacher's 24 students, 22 students, all ineligible for vaccination because of age, received testing for SARS-CoV-2; 12 received positive test results. The attack rate in the two rows seated closest to the teacher's desk was 80% (eight of 10) and was 28% (four of 14) in the three back rows (Fisher's exact test; p = 0.036). During May 24-June 1, six of 18 students in a separate grade at the school, all also too young for vaccination, received positive SARS-CoV-2 test results. Eight additional cases were also identified, all in parents and siblings of students in these two grades. Among these additional cases, three were in persons fully vaccinated in accordance with CDC recommendations (1). Among the 27 total cases, 22 (81%) persons reported symptoms; the most frequently reported symptoms were fever (41%), cough (33%), headache (26%), and sore throat (26%). WGS of all 18 available specimens identified the B.1.617.2 (Delta) variant. Vaccines are effective against the Delta variant (2), but risk of transmission remains elevated among unvaccinated persons in schools without strict adherence to prevention strategies. In addition to vaccination for eligible persons, strict adherence to nonpharmaceutical prevention strategies, including masking, routine testing, facility ventilation, and staying home when symptomatic, are important to ensure safe in-person learning in schools (3).

Identification of a novel bovine copiparvovirus in pooled fetal bovine serum.

A novel parvovirus was identified as a cell culture contaminant by metagenomic analysis. Droplet digital PCR (ddPCR) was used to determine viral loads in the cell culture supernatant and further analysis, by ddPCR and DNA sequencing, demonstrated that fetal bovine serum (FBS) used during cell culture was the source of the parvovirus contamination. The FBS contained ~ 50,000 copies of the novel parvovirus DNA per ml of serum. The viral DNA was resistant to DNAse digestion. Near-full length sequence of the novel parvovirus was determined. Phylogenetic analysis demonstrated that virus belongs to the Copiparvovirus genus, being most closely related to bovine parvovirus 2 (BPV2) with 41% identity with the non-structural protein NS1 and 47% identity with the virus capsid protein of BPV2. A screen of individual and pooled bovine sera identified a closely related variant of the novel virus in a second serum pool. For classification purposes, the novel virus has been designated bovine copiparvovirus species 3 isolate JB9 (bocopivirus 3-JB9).

Detection and complete genome characterization of a novel RNA virus related to members of the Hepe-Virga clade in bird species, hoopoe (Upupa epops).

Using viral metagenomics, next-generation sequencing and RT-PCR techniques a genetically divergent hepevirus-like RNA virus was identified and characterized from a faecal sample of wild bird species, hoopoe (Upupa epops) in Hungary. The complete viral genome sequence of hoopoe/BBanka01/2015/HUN (GenBank accession number MN852439) is 7052 nt long including a 54-nt 5' and an 18-nt 3' non-coding region without poly(A)-tail. Sequence analysis indicated that the hoopoe/BBanka01/2015/HUN genome has potentially three overlapping open reading frames (ORFs). The ORF1 (6558 nt/2185aa) encodes a long, non-structural polyprotein (replicase) including putative functional domains and conserved aa motifs of methyltransferase with domain Y, RNA helicase and RdRp and has <33% aa identity to the known hepe- and hepe-like viruses. The ORF2 (1446 nt/481aa) encodes a putative structural (capsid) protein overlapping with ORF1 but translated in different coding frame. The functions of the short ORF3 (426 nt/141aa) were not predictable. Similar virus sequences were not detected from samples from 21 further bird species. The taxonomic position of this novel virus is presently unknown.

Analysis of a novel RNA virus in a wild northern white-breasted hedgehog (Erinaceus roumanicus).

Tombusviruses are generally considered plant viruses. A novel tombus-/carmotetravirus-like RNA virus was identified in a faecal sample and blood and muscle tissues from a wild northern white-breasted hedgehog (Erinaceus roumanicus). The complete genome of the virus, called H14-hedgehog/2015/HUN (GenBank accession number MN044446), is 4,118 nucleotides in length with a readthrough stop codon of type/group 1 in ORF1 and lacks a poly(A) tract at the 3' end. The predicted ORF1-RT (RdRp) and the capsid proteins had low (31-33%) amino acid sequence identity to unclassified tombus-/noda-like viruses (Hubei tombus-like virus 12 and Beihai noda-like virus 10), respectively, discovered recently in invertebrate animals. An in vivo experimental plant inoculation study showed that an in vitro-transcribed H14-hedgehog/2015/HUN viral RNA did not replicate in Nicotiana benthamiana, Chenopodium quinoa, or Chenopodium murale, the most susceptible hosts for plant-origin tombusviruses.

Molecular characterization of a novel picobirnavirus in a chicken.

Picobirnaviruses (PBVs) are bisegmented viruses with a wide geographical and host species distribution. The number of novel PBV sequences has been increasing with the help of the viral metagenomics. A novel picobirnavirus strain, pbv/CHK/M3841/HUN/2011, was identified by viral metagenomics; the complete segment 1 (MH327933) and 2 (MH327934) sequences were obtained by RT-PCR from a cloacal sample of a diseased broiler breeder pullet in Hungary. Although the conserved nucleotide (e.g., ribosome binding site) and amino acid motifs (e.g., ExxRxNxxxE, S-domain of the viral capsid and motifs in the RNA-dependent RNA polymerase) were identifiable in the chicken picobirnavirus genome, the putative segment 1 showed low (< 30%) amino acid sequence identity to the corresponding proteins of marmot and dromedary PBVs, while segment 2 showed higher (< 70%) amino acid sequence identity to a wolf PBV protein sequence. This is the first full-genome picobirnavirus sequence from a broiler breeder chicken, but the pathogenicity of this virus is still questionable.

Detection of a novel RNA virus with hepatitis E virus-like non-structural genome organization in amphibian, agile frog (Rana dalmatina) tadpoles.

In recent years, relatives (bastrovirus, hepelivirus) of hepeviruses (family Hepeviridae) have been reported in a variety of vertebrate hosts. Preliminary studies indicated that inter-viral family recombination events at the junction of the genomes that encodes non-structural (ORF1) and structural protein (ORF2) were implicated in the genesis of hepeviruses. Using viral metagenomics, next generation sequencing and RT-PCR techniques a genetically divergent hepevirus-like RNA virus was identified and characterized from agile frog (Rana dalmatina) tadpoles living in aquatic environment in three natural ponds (Mélymocsár, Lake Ilona and Lake Katlan) in the Pilis Mountains, in Hungary. The complete genome of the viral strain agile frog/RD6/2015/HUN (MH330682) is 7188 nt long including a 48-nt 5' and a 122-nt 3' non-coding region. Sequence analysis indicated that the agile frog/RD6/2015/HUN genome has potentially three non-overlapping ORFs. ORF1 (4740 nt/1579aa) has a hepevirus-like non-structural genome organization and encodes several hepevirus-like amino acid sequence motifs. The ORF2 is a potential capsid protein. The functions of the ORF3 were not predictable. The study virus was present in 18 (46%) of the 39 faecal specimen pools from agile frog tadpoles. The taxonomic position of this novel virus is presently unknown.

Dicipivirus (family Picornaviridae) in wild Northern white-breasted hedgehog (Erinaceus roumanicus).

Using random amplification and high-throughput sequencing technology a novel picornavirus with dicistronic genome organization and genetically related to canine picodicistrovirus (genus Dicipivirus, family Picornaviridae) was identified and characterized in Northern white-breasted hedgehogs. Hedgehog dicipivirus (hedgehog/H14/2015/HUN, MF188967) was detected in 15 (75%) of 20 faecal specimens by RT-PCR with high viral loads (up to 8.2x108 genomic copies/ml faeces). Hedgehog dicipivirus RNA was also identified in blood, ear skin, abdominal muscle and liver tissues. While the general dicistronic genome organization of hedgehog/H14/2015/HUN is similar to canine picodicistrovirus (5'UTR-P1-IGR-P2/P3-3UTR) there are some unique genome characteristics within the untranslated regions, especially in the functional IRES elements. This study reports the putative second member of the genus Dicipivirus, in a novel host species.

A Naturally Transmitted Epitheliotropic Polyomavirus Pathogenic in Immunodeficient Rats: Characterization, Transmission, and Preliminary Epidemiologic Studies.

We report the identification, pathogenesis, and transmission of a novel polyomavirus in severe combined immunodeficient F344 rats with null Prkdc and interleukin 2 receptor gamma genes. Infected rats experienced weight loss, decreased fecundity, and mortality. Large basophilic intranuclear inclusions were observed in epithelium of the respiratory tract, salivary and lacrimal glands, uterus, and prostate gland. Unbiased viral metagenomic sequencing of lesioned tissues identified a novel polyomavirus, provisionally named Rattus norvegicus polyomavirus 2 (RatPyV2), which clustered with Washington University (WU) polyomavirus in the Wuki clade of the Betapolyomavirus genus. In situ hybridization analyses and quantitative polymerase chain reaction (PCR) results demonstrated viral nucleic acids in epithelium of respiratory, glandular, and reproductive tissues. Polyomaviral disease was reproduced in Foxn1rnu nude rats cohoused with infected rats or experimentally inoculated with virus. After development of RatPyV2-specific diagnostic assays, a survey of immune-competent rats from North American research institutions revealed detection of RatPyV2 in 7 of 1,000 fecal samples by PCR and anti-RatPyV2 antibodies in 480 of 1,500 serum samples. These findings suggest widespread infection in laboratory rat populations, which may have profound implications for established models of respiratory injury. Additionally, RatPyV2 infection studies may provide an important system to investigate the pathogenesis of WU polyomavirus diseases of man.

Ljungan/Sebokele-like picornavirus in birds of prey, common kestrel (Falco tinnunculus) and red-footed falcon (F. vespertinus).

Ljungan and Sebokele viruses are thought to be rodent-borne (picorna)viruses in the genus Parechovirus. Using random amplification and next generation sequencing method a novel Ljungan/Sebokele-like picornavirus was identified in birds of prey. Viral RNA was detected in total of 1 (9%) of the 11 and 2 (28.6%) of the 7 faecal samples from common kestrels and red-footed falcons in Hungary, respectively. High faecal viral RNA load (4.77×106 genomic copies/ml) measured by qPCR. The complete genome of picornavirus strain falcon/HA18_080/2014/HUN (KY645497) is 7964-nucleotide (nt) long including a 867-nt 5'end and a 101-nt 3'end (excluding the poly(A)-tail). Falcon/HA18_080/2014/HUN has type-II IRES related to hunnivirus IRES, encodes a polyprotein lacking a leader protein, a VP0 maturation cleavage site and it predicted to encode three 2A proteins (2A1NPG↓P, 2A2NPG↓P and 2A3H-Box/NC), two of them end with 'ribosome-skipping' sites (DxExNPG↓P). Sequence analyses indicated that the ORF1 (6996nt) polyprotein (2331 amino acid - aa) of falcon/HA18_080/2014/HUN shares the highest aa identity, 59% and 57%, to the corresponding polyproteins of Ljungan and Sebokele viruses. This study reports the identification and complete genome characterization of a novel Ljungan/Sebokele-like picornavirus in faeces of birds of prey which suggests that the genetic diversity and the potential host species spectrum of Ljungan/Sebokele-like viruses in genus Parechovirus are wider than previously thought.

Genome Sequence of Canine Polyomavirus in Respiratory Secretions of Dogs with Pneumonia of Unknown Etiology.

We report here the first canine polyomavirus genome, identified by metagenomics in respiratory secretions of two dogs with severe pneumonia, which tested negative for all canine respiratory pathogens except Mycoplasma cynos The isolate, Canis familiaris polyomavirus 1 (DogPyV-1), is a beta polyomavirus whose closest known LT antigen relatives are primate polyomaviruses.

Case-Control Comparison of Enteric Viromes in Captive Rhesus Macaques with Acute or Idiopathic Chronic Diarrhea.

Diarrhea is the major cause of non-research-associated morbidity and mortality affecting the supply of rhesus macaques and, potentially, their responses to experimental treatments. Idiopathic chronic diarrhea (ICD) in rhesus macaques also resembles ulcerative colitis, one form of human inflammatory bowel disease. To test for viral etiologies, we characterized and compared the fecal viromes from 32 healthy animals, 31 animals with acute diarrhea, and 29 animals with ICD. The overall fractions of eukaryotic viral reads were 0.063% for the healthy group, 0.131% for the acute-diarrhea group, and 0.297% for the chronic-diarrhea group. Eukaryotic viruses belonging to 6 viral families, as well as numerous circular Rep-encoding single-stranded DNA (CRESS DNA) viral genomes, were identified. The most commonly detected sequences were from picornaviruses, making up 59 to 88% of all viral reads, followed by 9 to 17% for CRESS DNA virus sequences. The remaining 5 virus families, Adenoviridae, Astroviridae, Anelloviridae, Picobirnaviridae, and Parvoviridae, collectively made up 1 to 3% of the viral reads, except for parvoviruses, which made up 23% of the viral reads in the healthy group. Detected members of the families Picornaviridae and Parvoviridae were highly diverse, consisting of multiple genera, species, and genotypes. Coinfections with members of up to six viral families were detected. Complete and partial viral genomes were assembled and used to measure the number of matching short sequence reads in feces from the 92 animals in the two clinical and the healthy control groups. Several enterovirus genotypes and CRESS DNA genomes were associated with ICD relative to healthy animals. Conversely, higher read numbers from different parvoviruses were associated with healthy animals. Our study reveals a high level of enteric coinfections with diverse viruses in a captive rhesus macaque colony and identifies several viruses positively or negatively associated with ICD.

Virome of US bovine calf serum.

Using viral metagenomics we analyzed four bovine serum pools assembled from 715 calves in the United States. Two parvoviruses, bovine parvovirus 2 (BPV2) and a previously uncharacterized parvovirus designated as bosavirus (BosaV), were detected in 3 and 4 pools respectively and their complete coding sequences generated. Based on NS1 protein identity, bosavirus qualifies as a member of a new species in the copiparvovirus genus. Also detected were low number of reads matching ungulate tetraparvovirus 2, bovine hepacivirus, and several papillomaviruses. This study further characterizes the diversity of viruses in calf serum with the potential to infect fetuses and through fetal bovine serum contaminate cell cultures.

A novel avian-like hepatitis E virus in wild aquatic bird, little egret (Egretta garzetta), in Hungary.

Hepatitis E virus (HEV), family Hepeviridae, has public health concerns because of its zoonotic potential; however, the host species spectrum, animal to animal transmissions, the natural chain of hepevirus infections and the genetic diversity of HEV in wildlife especially in birds are less known. Using random amplification and next generation sequencing technology a genetically divergent avian HEV was serendipitously identified in wild bird in Hungary. HEV RNA was detected with high faecal viral load (1.33×108genomiccopies/ml) measured by real-time PCR in faecal sample from a little egret (Egretta garzetta). The complete genome of HEV strain little egret/kocsag02/2014/HUN (KX589065) is 6660-nt long including a 18-nt 5' end and a 103-nt 3' end (excluding the poly(A)-tail). Sequence analyses indicated that the ORF1 (4554nt/1517aa), ORF2 (1728nt/593aa) and ORF3 (339nt/112aa) encoded proteins of little egret/kocsag02/2014/HUN shared the highest identity (62.8%, 71% and 61.5%) to the corresponding proteins of genotype 1 avian (chicken) HEV in species Orthohepevirus B, respectively. This study reports the identification and complete genome characterization of a novel orthohepevirus distantly related to avian (chicken) HEVs at the first time in wild bird. It is important to recognize all potential hosts, reservoirs and spreaders in nature and to reconstruct the phylogenetic history of hepeviruses. Birds could be an important reservoir of HEV generally and could be infected with genetically highly divergent strains of HEV.

A new protoparvovirus in human fecal samples and cutaneous T cell lymphomas (mycosis fungoides).

We genetically characterized seven nearly complete genomes in the protoparvovirus genus from the feces of children with diarrhea. The viruses, provisionally named cutaviruses (CutaV), varied by 1-6% nucleotides and shared ~76% and ~82% amino acid identity with the NS1 and VP1 of human bufaviruses, their closest relatives. Using PCR, cutavirus DNA was found in 1.6% (4/245) and 1% (1/100) of diarrhea samples from Brazil and Botswana respectively. In silico analysis of pre-existing metagenomics datasets then revealed closely related parvovirus genomes in skin biopsies from patients with epidermotropic cutaneous T-cell lymphoma (CTCL or mycosis fungoides). PCR of skin biopsies yielded cutavirus DNA in 4/17 CTCL, 0/10 skin carcinoma, and 0/21 normal or noncancerous skin biopsies. In situ hybridization of CTCL skin biopsies detected viral genome within rare individual cells in regions of neoplastic infiltrations. The influence of cutavirus infection on human enteric functions and possible oncolytic role in CTCL progression remain to be determined.

Divergent hepatitis E virus in birds of prey, common kestrel (Falco tinnunculus) and red-footed falcon (F. vespertinus), Hungary.

Hepatitis E virus (HEV), family Hepeviridae, has raised considerable public health concerns because of its zoonotic potential; however, the animal to animal transmissions and the natural chain of hepevirus infections in wildlife are less known. Using random amplification and next generation sequencing technology a novel HEV in birds of prey was serendipitously identified in Hungary. HEV RNA was detected in total of 2 (18%) of the 11 and 1 (14%) of the 7 faecal samples from common kestrels and red-footed falcons, respectively. High faecal viral load (2.03×10(8) genomic copies/ml) measured by qPCR. The complete genome of strain kestrel/MR22/2014/HUN (KU670940) HEV is 7033-nt long including a 35-nt 5'end and a 63-nt 3'end (excluding the poly(A)-tail). Sequence analyses indicated that the ORF1 (4920nt/639 aa), ORF2 (1989nt/662 aa) and ORF3 (360nt/119aa) proteins of kestrel/MR22/2014/HUN shared the highest identity (58.1%, 66.8% and 28.5%) to the corresponding proteins of ferret, rat and human genotype 4 Orthohepeviruses, respectively. Interestingly, the ORF3 protein is potentially initiated with leucine (L) using an alternate, non-AUG (UUG) start codon. This study reports the identification and complete genome characterization of a novel Orthohepevirus species related to mammalian HEVs in birds of prey. It is important to recognize all potential hosts, reservoirs and spreaders in nature and to reconstruct the phylogenetic history of hepeviruses.

Detection and genome analysis of a novel (dima)rhabdovirus (Riverside virus) from Ochlerotatus sp. mosquitoes in Central Europe.

During an investigation for potential arboviruses present in mosquitoes in Hungary (Central Europe) three highly similar virus strains of a novel rhabdovirus (family Rhabdoviridae) called Riverside virus (RISV, KU248085-KU248087) were detected and genetically characterized from Ochlerotatus sp. mosquito pools collected from 3 geographical locations using viral metagenomic and RT-PCR methods. The ssRNA(-) genome of RISVs follows the general genome layout of rhabdoviruses (3'-N-P-M-G-L-5') with two alternatives, small ORFs in the P and G genes (Px and Gx). The genome of RISVs contains some unusual features such as the large P proteins, the short M proteins with the absence of N-terminal region together with the undetectable "Late budding" motif and the overlap of P and M genes. The unusually long 3' UTRs of the M genes of RISVs probably contain a remnant transcription termination signal which is suggesting the presence of an ancestral gene. The phylogenetic analysis and sequence comparisons show that the closest known relative of RISVs is the recently identified partially sequenced mosquito-borne rhabdovirus, North Creek virus (NOCRV), from Australia. The RISVs and NOCRV form a distinct, basally rooted lineage in the dimarhabdovirus supergroup. The host species range of RISVs is currently unknown, although the presence of these viruses especially in Ochlerotatus sp. mosquitoes which are known to be fierce biting pests of humans and warm-blooded animals and abundant and widespread in Hungary could hold some potential medical and/or veterinary risks.

Limited Variation in BK Virus T-Cell Epitopes Revealed by Next-Generation Sequencing.

BK virus (BKV) infection causing end-organ disease remains a formidable challenge to the hematopoietic cell transplant (HCT) and kidney transplant fields. As BKV-specific treatments are limited, immunologic-based therapies may be a promising and novel therapeutic option for transplant recipients with persistent BKV infection. Here, we describe a whole-genome, deep-sequencing methodology and bioinformatics pipeline that identify BKV variants across the genome and at BKV-specific HLA-A2-, HLA-B0702-, and HLA-B08-restricted CD8 T-cell epitopes. BKV whole genomes were amplified using long-range PCR with four inverse primer sets, and fragmentation libraries were sequenced on the Ion Torrent Personal Genome Machine (PGM). An error model and variant-calling algorithm were developed to accurately identify rare variants. A total of 65 samples from 18 pediatric HCT and kidney recipients with quantifiable BKV DNAemia underwent whole-genome sequencing. Limited genetic variation was observed. The median number of amino acid variants identified per sample was 8 (range, 2 to 37; interquartile range, 10), with the majority of variants (77%) detected at a frequency of <5%. When normalized for length, there was no statistical difference in the median number of variants across all genes. Similarly, the predominant virus population within samples harbored T-cell epitopes similar to the reference BKV strain that was matched for the BKV genotype. Despite the conservation of epitopes, low-level variants in T-cell epitopes were detected in 77.7% (14/18) of patients. Understanding epitope variation across the whole genome provides insight into the virus-immune interface and may help guide the development of protocols for novel immunologic-based therapies.

Local Virus Extinctions following a Host Population Bottleneck.

UNLABELLED: A small number of African green monkeys (AGMs) were introduced into the Caribbean from West Africa in the 1600s. To determine the impact of this population bottleneck on the AGM virome, we used metagenomics to compare the viral nucleic acids in the plasma of 43 wild AGMs from West Africa (Gambia) to those in 44 AGMs from the Caribbean (St. Kitts and Nevis). Three viruses were detected in the blood of Gambian primates: simian immunodeficiency virus (SIVagm; in 42% of animals), a novel simian pegivirus (SPgVagm; in 7% of animals), and numerous novel simian anelloviruses (in 100% of animals). Only anelloviruses were detected in the Caribbean AGMs with a prevalence and levels of viral genetic diversity similar to those in the Gambian animals. A host population bottleneck therefore resulted in the exclusion of adult-acquired SIV and pegivirus from the Caribbean AGMs. The successful importation of AGM anelloviruses into the Caribbean may be the result of their early transmission to infants, very high prevalence in African AGMs, and frequent coinfections with as many as 11 distinct variants. IMPORTANCE: The extent to which viruses can persist in small isolated populations depends on multiple host, viral, and environmental factors. The absence of prior infections may put an immunologically naive population at risk for disease outbreaks. Isolated populations originating from a small number of founder individuals are therefore considered at increased risk following contact with populations with a greater variety of viruses. Here, we compared the plasma virome of West African green monkeys to that in their descendants after importation of a small number of animals to the Caribbean. A lentivirus and a pegivirus were found in the West African population but not in the Caribbean population. Highly diverse anelloviruses were found in both populations. A small founder population, limited to infants and young juvenile monkeys, may have eliminated the sexually transmitted viruses from the Caribbean AGMs, while anelloviruses, acquired at an earlier age, persisted through the host population bottleneck.

What is for dinner? Viral metagenomics of US store bought beef, pork, and chicken.

We describe here the metagenomics-derived viral sequences detected in beef, pork, and chicken purchased from stores in San Francisco. In beef we detected four previously reported viruses (two parvoviruses belonging to different genera, an anellovirus, and one circovirus-like virus) and one novel bovine polyomavirus species (BPyV2-SF) whose closest relatives infect primates. Detection of porcine hokovirus in beef indicated that this parvovirus can infect both ungulate species. In pork we detected four known parvoviruses from three genera, an anellovirus, and pig circovirus 2. Chicken meat contained numerous gyrovirus sequences including those of chicken anemia virus and of a novel gyrovirus species (GyV7-SF). Our results provide an initial characterization of some of the viruses commonly found in US store-bought meats which included a diverse group of parvoviruses and viral families with small circular DNA genomes. Whether any of these viruses can infect humans will require testing human sera for specific antibodies.

Faecal virome of cats in an animal shelter.

We describe the metagenomics-derived feline enteric virome in the faeces of 25 cats from a single shelter in California. More than 90 % of the recognizable viral reads were related to mammalian viruses and the rest to bacterial viruses. Eight viral families were detected: Astroviridae, Coronaviridae, Parvoviridae, Circoviridae, Herpesviridae, Anelloviridae, Caliciviridae and Picobirnaviridae. Six previously known viruses were also identified: feline coronavirus type 1, felid herpes 1, feline calicivirus, feline norovirus, feline panleukopenia virus and picobirnavirus. Novel species of astroviruses and bocaviruses, and the first genome of a cyclovirus in a feline were characterized. The RNA-dependent RNA polymerase region from four highly divergent partial viral genomes in the order Picornavirales were sequenced. The detection of such a diverse collection of viruses shed within a single shelter suggested that such animals experience robust viral exposures. This study increases our understanding of the viral diversity in cats, facilitating future evaluation of their pathogenic and zoonotic potentials.