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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 2024. The entire ICTV membership was invited to vote on 203 taxonomic proposals that had been approved by the ICTV Executive Committee (EC) in July 2023 at the 55th EC meeting in Jena, Germany, or in the second EC vote in November 2023. All proposals were ratified by online vote. Taxonomic additions include one new phylum (Ambiviricota), one new class, nine new orders, three new suborders, 51 new families, 18 new subfamilies, 820 new genera, and 3547 new species (excluding taxa that have been abolished). Proposals to complete the process of species name replacement to the binomial (genus + species epithet) format were ratified. Currently, a total of 14,690 virus species have been established.

In March 2022, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by two new families (bunyaviral Discoviridae and Tulasviridae), 41 new genera, and 98 new species. Three hundred forty-nine species were renamed and/or moved. The accidentally misspelled names of seven species were corrected. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

As part of a broad One Health surveillance effort to detect novel viruses in wildlife and people, we report several paramyxovirus sequences sampled primarily from bats during 2013 and 2014 in Brazil and Malaysia, including seven from which we recovered full-length genomes. Of these, six represent the first full-length paramyxovirid genomes sequenced from the Americas, including two that are the first full-length bat morbillivirus genome sequences published to date. Our findings add to the vast number of viral sequences in public repositories, which have been increasing considerably in recent years due to the rising accessibility of metagenomics. Taxonomic classification of these sequences in the absence of phenotypic data has been a significant challenge, particularly in the subfamily Orthoparamyxovirinae, where the rate of discovery of novel sequences has been substantial. Using pairwise amino acid sequence classification (PAASC), we propose that five of these sequences belong to members of the genus Jeilongvirus and two belong to members of the genus Morbillivirus. We also highlight inconsistencies in the classification of Tupaia virus and Mòjiāng virus using the same demarcation criteria and suggest reclassification of these viruses into new genera. Importantly, this study underscores the critical importance of sequence length in PAASC analysis as well as the importance of biological characteristics such as genome organization in the taxonomic classification of viral sequences.

In March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

Investigations conducted during the spring 2020 season to diagnose the associated viral agent of a severe mosaic disease of wheat in a Texas Panhandle field revealed the presence of wheat Eqlid mosaic virus (WEqMV; genus Tritimovirus, family Potyviridae) in the analyzed samples. The complete genome sequences of two WEqMV isolates were determined, and each was found to be 9,634 nucleotides (nt) in length (excluding the polyA tail) and to contain 5’ and 3’ untranslated regions of 135 nt and 169 nt, respectively, based on rapid amplification of cDNA ends (RACE) assays. Both sequences contained an open reading frame (ORF) of 9,330 nt encoding a polyprotein of 3,109 amino acids (aa). The ORF sequences of the two isolates were 100% identical to each other, but only 74.7% identical to that of the exemplar WEqMV-Iran isolate, with 85.7% aa sequence identity in the encoded polyprotein. The Texas WEqMV isolates also diverged significantly from WEqMV-Iran in the individual proteins at the nt and aa levels. This is the first report of WEqMV in the United States and the first report of this virus outside of Iran, indicating an expansion of its geographical range. [ABSTRACT FROM AUTHOR]

Bermuda grass latent virus (BGLV; genus Panicovirus) is identified for the first time in Australia and in only the second country after the USA. A full-length genome sequence was obtained, which has 97% nucleotide sequence identity to that of the species exemplar isolate. Surveys for BGLV, utilising a newly designed universal panicovirus RT-PCR assay for diagnosis, demonstrated widespread infection by this virus in a broad variety of Bermuda grass cultivars (Cynodon dactylon and C. dactylon × C. transvaalensis) grown in both New South Wales and Queensland. The virus was also detected in Rhodes grass (Chloris gayana) and Kikuyu grass (Cenchrus clandestinus), which are both important pasture grasses in subtropical Australia, and the latter is also grown as turf. Furthermore, the Rhodes grass plant, which had strong mosaic symptoms, was also infected with sugarcane mosaic virus, warranting further investigations as to whether synergistic interactions occur between these two viruses. [ABSTRACT FROM AUTHOR]

The current prevalence of avian leukosis virus (ALV) in fancy chickens in Germany is unknown. Therefore, 537 cloacal swabs from 50 purebred fancy-chicken flocks in Saxony were tested for the presence of the ALV p27 protein using a commercial antigen-capture ELISA. The detection rate was 28.7% at the individual-animal level and 56.0% at the flock level. Phylogenetic analysis of PCR products obtained from 22 different flocks revealed the highest similarity to ALV subtype K. When classifying breeds by their origin, ALV detection rates differed significantly. Evaluation of questionnaire data revealed no significant differences between ALV-positive and negative flocks regarding mortality. [ABSTRACT FROM AUTHOR]

Following the results of the International Committee on Taxonomy of Viruses (ICTV) Ratification Vote held in March 2021, a standard two-part "binomial nomenclature" is now the norm for naming virus species. Adoption of the new nomenclature is still in its infancy; thus, it is timely to reiterate the distinction between "virus" and "virus species" and to provide guidelines for naming and writing them correctly. [ABSTRACT FROM AUTHOR]

The complete genomic sequence of a plant rhabdovirus that was identified in Cnidium officinale in Yeongyang-dun, South Korea, is reported here. The virus, tentatively named "cnidium virus 1" (CnV1), has a negative-sense RNA genome of ~ 14 kb, and its organization most closely resembles that of unsegmented plant rhabdoviruses, containing six antisense open reading frames (ORFs) in the order 3′-N-P-P3-M-G-L-5′. Intergenic regions containing conserved sequences separate the genes. The genome of CnV1 is 37.8–56% identical in its complete nucleotide sequence to betanucleorhabdoviruses and other related rhabdoviruses. Therefore, based on the sequence similarity criteria for species demarcation, its genome organization, and its phylogenetic position, CnV1 should be classified as a new member of the genus Betanucleorhabdovirus in the family Rhabdoviridae. CnV1 is the first rhabdovirus found in C. officinale. [ABSTRACT FROM AUTHOR]

A tobamovirus was isolated from leaves of a Scopolia japonica plant showing mild yellowing. Back-inoculation of healthy Scopolia japonica with the isolated virus induced mild mottle on upper leaves. Phylogenetic analysis based on coat protein and replicase protein sequences revealed that the newly isolated tobamovirus was most closely related to yellow tailflower mild mottle virus (YTMMV). The newly isolated tobamovirus shared the highest nucleotide sequence identity (71%) with YTMMV, which is lower than the cutoff (90%) set for species demarcation in the genus Tobamovirus. Thus, our result suggested that scopolia mild mottle virus (SMMoV) is a new tobamovirus that infects Scopolia japonica plants in Japan. [ABSTRACT FROM AUTHOR]

A survey was performed on a Vitis cultivar collection in Stellenbosch, South Africa. Metaviromes were generated for each cultivar, using an RNAtag-seq workflow. Analysis of assembled contigs indicated the presence of two putatively novel members of the genus Vitivirus, provisionally named "grapevine virus N" (GVN) and "grapevine virus O" (GVO). Comparisons of amino acid sequences showed that GVN and GVO are most closely related to grapevine virus G and grapevine virus E, respectively. The incidence of these novel viruses within the sampling site was low, with GVO and GVN associated with only five and two cultivars, respectively, of the 229 sampled. [ABSTRACT FROM AUTHOR]

Here, we propose the creation of the family "Yaraviridae", a new taxon to classify a virus infecting Acanthamoeba castellanii cells. Recently, we described the discovery of a new virus infecting free-living amoebae, yaravirus, which has features that strongly differ from those of all other viruses of amoebae described to date. Yaravirus particles are about 80 nm in diameter and have a dsDNA genome of ~45 kbp containing 74 ORFs, most of which (>90%) have no homologs in current databases. Together, these data support the creation of a new species ("Yaravirus brasiliense"), a new viral genus (here proposed as "Yaravirus"), and a new viral family (here proposed as "Yaraviridae") to classify yaravirus and other related viruses that may be described in the future. All of them are to be included into the existing realm Varidnaviria and the kingdom Bamfordvirae, due to the presence of a major capsid protein containing a double jelly-roll fold. [ABSTRACT FROM AUTHOR]

Ticks are blood-sucking arthropods that transmit many pathogens, including arboviruses. Arboviruses transmitted by ticks are generally referred to as tick-borne viruses (TBVs). TBVs are known to cause diseases in humans, pets, and livestock. There is, however, very limited information on the occurrence and distribution of TBVs in sub-Saharan Africa. This study was designed to determine the presence and distribution of ticks infesting dogs and cattle in Ghana, as well as to identify the tick-borne or tick-associated viruses they harbour. A more diverse population of ticks was found to infest cattle (three genera) relative to those infesting dogs (one genus). Six phleboviruses and an orthonairovirus were detected in tick pools screened by RT-PCR. Subsequent sequence analysis revealed two distinct phleboviruses and the previously reported Odaw virus in ticks collected from dogs and a virus (16GH-T27) most closely related to four unclassified phleboviruses in ticks collected from cattle. The virus 16GH-T27 was considered a strain of Balambala tick virus (BTV) and named BTV strain 16GH-T27. Next-generation sequencing analysis of the BTV-positive tick pool detected only the L and S segments. Phylogenetic analysis revealed that BTV clustered with viruses previously defined as M-segment-deficient phleboviruses. The orthonairovirus detected in ticks collected from cattle was confirmed to be the medically important Dugbe virus. Furthermore, we discuss the importance of understanding the presence and distribution of ticks and TBVs in disease prevention and mitigation and the implications for public health. Our findings contribute to the knowledge pool on TBVs and tick-associated viruses. [ABSTRACT FROM AUTHOR]

Viral stability under stress conditions may directly affect viral dissemination, seasonality, and pathogenesis. We exposed airborne viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), mumps virus, coxsackievirus B5, human rhinovirus A16, and respiratory syncytial virus, to different temperatures, UV light exposure time, pH values, and osmotic pressures and measured the remaining viral infectivity. Reduced thermal stability was observed for coxsackievirus B5 at 45 °C, while SARS-CoV-2 demonstrated residual infectivity at 55 °C. UV light exposure was an efficient means of viral inactivation but was less efficient for non-enveloped viruses. Rhinovirus A16 and respiratory syncytial virus demonstrated extreme sensitivity to acid conditions, while SARS-CoV-2, rhinovirus A16, and respiratory syncytial virus were unstable in an alkaline environment. The information obtained in this study will be useful for the development of viral inactivation methods and may be correlated with epidemiological and seasonal viral characteristics. [ABSTRACT FROM AUTHOR]

Members of the family Circoviridae are known to infect several avian species, with the ability to cause severe disease outcomes in some species. Using a high-throughput sequencing-informed approach, we identified two novel lineages of circoviruses, referred to as wigfec circovirus 1 and 2, in faecal matter of American wigeons (Mareca americana) collected in Arizona, USA. Wigfec circovirus 1 was identified in eight samples and is most closely related to the other waterfowl circoviruses, sharing ~64% genome-wide sequence identity with duck circoviruses. On the other hand, wigfec circovirus 2 was identified in two samples and is most closely related to two circoviruses identified in bat samples, sharing ~71% genome-wide pairwise identity. Both novel circoviruses were recovered from samples collected at the same location two months apart. Furthermore, in one sample, both of these viruses were identified, indicating these viruses are likely common amongst these birds and/or their environment. [ABSTRACT FROM AUTHOR]

In this article, we – the Bacterial Viruses Subcommittee and the Archaeal Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV) – summarise the results of our activities for the period March 2020 – March 2021. We report the division of the former Bacterial and Archaeal Viruses Subcommittee in two separate Subcommittees, welcome new members, a new Subcommittee Chair and Vice Chair, and give an overview of the new taxa that were proposed in 2020, approved by the Executive Committee and ratified by vote in 2021. In particular, a new realm, three orders, 15 families, 31 subfamilies, 734 genera and 1845 species were newly created or redefined (moved/promoted). [ABSTRACT FROM AUTHOR]

During a survey in a tomato field in Luziânia (Goiás State, Brazil), a single plant with mottling, chlorotic spots, and leaf distortion was found. A new bipartite begomovirus sequence was identified using nanopore sequence technology and confirmed by Sanger sequencing. The highest nucleotide sequence identity match of the DNA-A component (2596 bases) was 81.64% with tomato golden leaf deformation virus (HM357456). Due to the current species demarcation criterion of 91% nucleotide sequence identity for DNA-A, we propose this virus to be a new member of the genus Begomovirus, named "tomato mottle leaf distortion virus". [ABSTRACT FROM AUTHOR]

A new positive-strand RNA virus genome was discovered in Camellia japonica plants. The complete genome of the virus is 12,570 nt in size, excluding the poly(A) tail, and contains one large open reading frame (ORF1) and two small open reading frames (ORF2, ORF3). ORF1 and ORF2 are homologous to sequences of waikaviruses, while ORF3 has no relatives in the databases. ORF1 encodes a putative polyprotein precursor that is putatively processed into eight smaller proteins, as in typical waikaviruses. Comprehensive analysis, including BLAST searches, genome organization and pairwise sequence comparisons, and phylogeny reconstructions, invariably placed the virus with the waikaviruses. Furthermore, due to lower amino acid sequence identity to known waikaviruses than the threshold species demarcation cutoff, this virus may represent a new species in the genus Waikavirus, family Secoviridae, and we have tentatively named it "camellia virus A" (CamVA). Finally, a field survey was conducted to assess the occurrence of CamVA in camellias and its associated symptoms. [ABSTRACT FROM AUTHOR]

Adenovirus, respiratory syncytial virus, and influenza virus are common causes of respiratory infections. The COVID-19 pandemic had a significant impact on their prevalence. The aim of this study was to analyze the epidemic changes of common respiratory viruses in the Affiliated Hospital of Hangzhou Normal University in Hangzhou, China, from October of 2017 to February of 2021. We collected statistics from 121,529 patients in the outpatient and inpatient departments of the hospital who had throat or nose swabs collected for testing for four virus antigens by the colloidal gold method. Of these, 13,200 (10.86%) were positive for influenza A virus, 8,402 (6.91%) were positive for influenza B virus, 6,056 (4.98%) were positive for adenovirus, and 4,739 (3.90%) were positive for respiratory syncytial virus. The positivity rates of the influenza A virus (0-14 years old, P = 0.376; over 14 years old, P = 0.197) and respiratory syncytial virus (0-14 years old, P = 0.763; over 14 years old, P = 0.465) did not differ significantly by gender. After January of 2020, influenza virus infection decreased significantly. The positivity rate of respiratory syncytial virus remained high, and its epidemic season was similar to before. Strict respiratory protection and regulation of crowd activities have a great impact on the epidemic characteristics of viruses. After major changes in the public health environment, virus epidemics and their mutations should be monitored closely, extensively, and continuously. [ABSTRACT FROM AUTHOR]

The genus Gyrovirus was assigned to the family Anelloviridae in 2017 with only one recognized species, Chicken anemia virus. Over the last decade, many diverse viruses related to chicken anemia virus have been identified but not classified. Here, we provide a framework for the classification of new species in the genus Gyrovirus and communicate the establishment of nine new species. We adopted the 'Genus + freeform epithet' binomial system for the naming of these species. [ABSTRACT FROM AUTHOR]

Watermelon crinkle leaf-associated virus 1 and watermelon crinkle leaf-associated virus 2 (WCLaV-1 and WCLaV-2), two unclassified members of the order Bunyavirales, are phylogenetically related to members of the genus Coguvirus (family Phenuiviridae). The genome of both viruses was reported previously to be composed of three RNA segments. However, the terminal sequences of two genomic RNA segments, namely those encoding the putative movement protein (MP) and the nucleocapsid (NP) protein, remained undetermined. High-throughput sequencing of total RNA and small RNA preparations, combined with reverse transcription PCR amplification followed by sequencing, revealed that the WCLaV-1 and WCLaV-2 possess a bipartite genome consisting of a negative-sense RNA1, encoding the RNA-dependent RNA polymerase, and an ambisense RNA2, encoding the putative movement (MP) and nucleocapsid (NP) proteins. The two open reading frames of RNA2 are in opposite orientations and are separated by a long AU-rich intergenic region (IR) that may assume a hairpin conformation. RNA1 and RNA2 of both viruses share almost identical 5' and 3' termini, which are complementary to each other up to 20 nt. This genome organization is typical of members of the genus Coguvirus, with which WCLaV-1 and WCLaV-2 also share similar terminal 5' and 3' sequences of RNA1 and RNA2. These molecular features, together with phylogenetic reconstructions support the classification of WCLaV-1 and WCLaV2 as members of two new species in the genus Coguvirus. [ABSTRACT FROM AUTHOR]

The complete genomic sequence of scorzonera virus A (SCoVA) from a Scorzonera austriaca Willd. plant in South Korea was determined by high-throughput sequencing and confirmed by Sanger sequencing. The SCoVA genome contains 9867 nucleotides, excluding the 3′-terminal poly(A) tail. The SCoVA genome structure is typical of potyviruses and contains a single open reading frame encoding a large putative polyprotein of 3168 amino acids. Pairwise comparison analysis of the complete genome and polyprotein sequences of SCoVA with those of other potyviruses showed that they shared the highest nucleotide and amino acid sequences identity (54.47% and 49.57%, respectively) with those of lettuce mosaic virus (GenBank accession number KJ161185). Phylogenetic analysis of the amino acid sequence of the polyprotein confirmed that SCoVA belongs to the genus Potyvirus. These findings suggest that SCoVA should be considered a novel member of the genus Potyvirus, family Potyviridae. [ABSTRACT FROM AUTHOR]

Deformed wing virus (DWV) has been linked to the global decline of honey bees. DWV exists as three master variants (DWV-A, DWV-B, and DWV-C), each with differing outcomes for the honey bee host. Research in the USA showed a shift from DWV-A to DWV-B between 2010 to 2016 in honey bee colonies. Likewise, in the UK, a small study in 2007 found only DWV-A, whereas in 2016, DWV-B was the most prevalent variant. This suggests a shift from DWV-A to DWV-B might have occurred in the UK between 2007 and 2016. To investigate this further, data from samples collected in 2009/10 (n = 46) were compared to existing data from 2016 (n = 42). These samples also allowed a comparison of DWV variants between Varroa-untreated (feral) and Varroa-treated (managed) colonies. The results revealed that, in the UK, DWV-A was far more prevalent in 2009/10 (87%) than in 2016 (43%). In contrast, DWV-B was less prevalent in 2009/10 (76%) than in 2016 (93%). Regardless if colonies had been treated for Varroa (managed) or not (feral), the same trend from DWV-A to DWV-B occurred. Overall, the results reveal a decrease in DWV-A and an increase in DWV-B in UK colonies. [ABSTRACT FROM AUTHOR]

Wheat plants showing yellowing and mosaic in leaves and stunting were collected from wheat fields in Henan Province, China. Analysis of these plants by transmission electron microscopy showed that they contained two types of filamentous virus-like particles with a length of 200-500 nm and 1000-1300 nm, respectively. RNA-seq revealed a coinfection with wheat yellow mosaic virus (WYMV) and an unknown wheat-infecting virus. The genome of the unknown virus is 8,410 nucleotides long, excluding its 3' poly(A) tail. It has six open reading frames (ORFs). ORF1 encodes a putative viral replication-associated protein (Rep), and ORFs 2, 3, and 4 encode the triple gene block (TGB) proteins. ORFs 5 and 6 encode the capsid protein (CP) and a protein with unknown function, respectively. Phylogenetic analysis showed that this novel virus is evolutionarily related to members of the subfamily Quinvirinae, family Betaflexiviridae. It is, however, distinct from the viruses in the currently established genera. Based on the species and genus demarcation criteria set by the International Committee on Taxonomy of Viruses (ICTV), we tentatively name this novel virus "wheat yellow stunt-associated betaflexivirus" (WYSaBV), and we propose it to be a member of a new genus in the family Betaflexiviridae. [ABSTRACT FROM AUTHOR]

This article reports the changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in March 2021. The entire ICTV was invited to vote on 290 taxonomic proposals approved by the ICTV Executive Committee at its meeting in October 2020, as well as on the proposed revision of the International Code of Virus Classification and Nomenclature (ICVCN). All proposals and the revision were ratified by an absolute majority of the ICTV members. Of note, ICTV mandated a uniform rule for virus species naming, which will follow the binomial 'genus-species' format with or without Latinized species epithets. The Study Groups are requested to convert all previously established species names to the new format. ICTV has also abolished the notion of a type species, i.e., a species chosen to serve as a name-bearing type of a virus genus. The remit of ICTV has been clarified through an official definition of 'virus' and several other types of mobile genetic elements. The ICVCN and ICTV Statutes have been amended to reflect these changes. [ABSTRACT FROM AUTHOR]

Barleria cristata L. has become naturalized in South Africa, where it is commonly used as an ornamental. In 2019, plants of B. cristata showing putative viral symptoms were collected from two locations in Gauteng, South Africa. RNAtag-seq libraries were prepared and sequenced using an Illumina HiSeq 2500 platform. De novo assembly of the resulting data revealed the presence of a novel member of the family Tospoviridae associated with the plants from both locations, and this virus was given the tentative name "barleria chlorosis-associated virus". Segments L, M, and S have lengths of 8752, 4760, and 2906 nt, respectively. Additionally, one of the samples was associated with a novel polerovirus, provisionally named "barleria polerovirus 1", with a complete genome length of 6096 nt. This is the first study to show the association of viruses with a member of the genus Barleria. [ABSTRACT FROM AUTHOR]

Viola mottle virus (VMoV) was discovered in Viola odorata showing symptoms of reduced growth, leaf mottling, and whitish stripes on flowers in northern Italy in 1977. This virus has been provisionally classified as a member of the genus Potexvirus based on its morphological, serological, and biological characteristics. However, since genetic information of VMoV has never been reported, the taxonomic status of this virus is unclear. Here, we report the first complete genome sequence of VMoV to clarify its taxonomic position. Its genomic RNA is 6,052 nucleotides long, excluding the 3′-terminal poly(A) tail, and has five open reading frames (ORFs) typical of potexviruses. Among potexviruses, VMoV showed the most similarity to tulip virus X (TVX) with 81.1–81.2% nucleotide and 90.4–90.7% amino acid sequence identity in ORF1 and 82.9–83.5% nucleotide and 93.2–95.2% amino acid sequence identity in ORF5. These values are much higher than the species demarcation threshold for the genus. Phylogenetic analysis also indicated that VMoV is nested within the clade of TVX isolates. These data demonstrate that VMoV and TVX are members of the same species. [ABSTRACT FROM AUTHOR]

Feline panleukopenia virus (FPV) is a highly contagious infectious pathogen of cats globally. However, there is no information on the molecular identification and characterization of FPV in Bangladesh. Here, 8.16% (8/98) and 18.37% (18/98) of diarrheic cats tested positive for FPV by an immunochromatography (IC) test and PCR, respectively. The IC test showed 44.44% sensitivity and 100% specificity in comparison with PCR. Our newly sequenced Bangladeshi FPV strain (MN826076) showed the highest (99.71%) sequence identity to strains from the United Arab Emirates (UAE). Strain MN826076 contained two characteristic amino acid variations in VP2 identifying it as an FPV strain: valine at position 103 and aspartic acid at position 323. Phylogenetically, the VP2 of strain MN826076 was found to be closely related to 19 FPV strains, sharing the same clade. [ABSTRACT FROM AUTHOR]

Frog virus 3 (FV3) was detected in cultured bullfrogs in Southeast Brazil. Phylodynamic analysis revealed recombination events in this strain that were nearly identical to those detected in North American and Brazilian FV3 strains. These data suggest that international trade of live bullfrogs has spread recombinant strains of FV3. [ABSTRACT FROM AUTHOR]

A novel positive-stranded RNA virus provisionally named "citrus virus C" (CVC) was discovered in citrus trees displaying mottling symptoms. Its genome comprises 7,215 nucleotides (nt), excluding the 3' poly(A) tail, and contains two open reading frames (ORFs) that encode a replication-associated polyprotein (RP) and a putative coat protein (CP). The CVC genome contains a 16-nt 'marafibox', which is highly conserved in most viruses belonging to the genus Marafivirus of the same family. Sequence analysis suggested that the virus is most closely related to grapevine Red Globe virus (GRGV), which is yet to be officially classified in the family Tymoviridae. The sequence identities between CVC and GRGV in the whole genome (50.7%, nt) and CP (49.4% for amino acid, and 53.9% for nt) are lower than the thresholds (80% in the genome and 90% in the CP) for species demarcation in the family. Therefore, it is legitimate to propose that CVC is a member of new species in the family Tymoviridae. [ABSTRACT FROM AUTHOR]

High-throughput sequencing (HTS) was used to construct the virome profile of an old grapevine-leafroll-diseased grapevine (Vitis vinifera). De novo assembly of HTS data showed a complex infection, including a virus sequence with similarity to viruses of the genus Badnavirus, family Caulimoviridae. The complete genome sequence of this virus consists of 7090 nucleotides and has four open reading frames (ORFs). Genome organisation and phylogenetic analysis identify this virus as a divergent variant of grapevine Roditis leaf discoloration-associated virus (GRLDaV) with 90% nucleotide sequence identity to isolate w4 (NC_027131). This is the first genome sequence of a South African variant of GRLDaV. [ABSTRACT FROM AUTHOR]

Beekeeping is a widespread activity in Argentina, mainly producing honey that has gained both national and international recognition. There are more than 3,000,000 hives in the country, mainly concentrated in Buenos Aires Province (approximately 1,000,000 hives). In recent decades, worrying rates of hive loss have been observed in many countries around the world. In Latin America, the estimated loss of hives is between 13% (Peru and Ecuador) and 53% (Chile). Argentina had annual losses of 34% for the period of October 1, 2016 to October 1, 2017. The causes of these losses are not clear but probably involve multiple stressors that can act simultaneously. One of the main causes of loss of bee colonies worldwide is infestation by the ectoparasitic mite Varroa destructor in combination with viral infections. To date, 10 viruses have been detected that affect honey bees (Apis mellifera) in Argentina. Of these, deformed wing virus, sacbrood virus, acute bee paralysis virus, chronic bee paralysis virus, and Israeli acute bee paralysis can be transmitted by mites. Deformed wing virus and the AIK complex are the viruses most often associated with loss of hives worldwide. Considering that bee viruses have been detected in Argentina in several hymenopteran and non-hymenopteran insects, these hosts could act as important natural reservoirs for viruses and play an important role in their dispersal in the environment. Further studies to investigate the different mechanisms by which viruses spread in the environment will enable us to develop various strategies for the control of infected colonies and the spread of viruses in the habitat where they are found. [ABSTRACT FROM AUTHOR]

Virus maturation is found in all animal viruses and dsDNA bacteriophages that have been studied. It is a programmed process, cued by cellular environmental factors, that transitions a noninfectious, initial assembly product (provirus) to an infectious particle (virion). Nudaurelia capensis omega virus (NωV) is an ssRNA insect virus with T=4 quasi-symmetry. Over the last 20 years, NωV virus-like particles (VLPs) have been an attractive model for the detailed study of maturation. The novel feature of the system is the progressive transition from procapsid to capsid controlled by pH. Homogeneous populations of maturation intermediates can be readily produced at arbitrary intervals by adjusting the pH between 7.6 and 5.0. These intermediates were investigated using biochemical and biophysical methods to create a stop-frame transition series of this complex process. The studies reviewed here characterized the large-scale subunit reorganization during maturation (the particle changes size from 48 nm to 41 nm) as well as the mechanism of a maturation cleavage, a time-resolved study of cleavage site formation, and specific roles of quasi-equivalent subunits in the release of membrane lytic peptides required for cellular entry. [ABSTRACT FROM AUTHOR]

Little cherry virus 2 (LChV-2) is a causal agent of little cherry disease, which produces small, misshapen fruit with poor color and taste. As LChV-2 symptoms are only present near harvest, molecular detection is essential for effective control. Therefore, we determined the titer and distribution of this virus in infected trees over time. While initial infections were found to be basipetal, in field trees, early-stage infection was characterized by uneven distribution and low titer, concentrated in woody stems. In contrast, established infections were systemic, and detection was consistent across tissues. These data provide improved sampling recommendations for the detection of LChV-2. [ABSTRACT FROM AUTHOR]

Common bean plants (Phaseolus vulgaris L.) showing different virus-like symptoms were collected in northwestern Argentina. Dot-blot hybridization tests showed that the begomoviruses bean golden mosaic virus and tomato yellow vein streak virus were the most prevalent, but they also revealed the presence of unknown begomoviruses. The complete genome sequence of one of these unknown begomoviruses was determined. Sequence analysis showed that the virus is a typical New World begomovirus, for which the name "bean bushy stunt virus" (BBSV) is proposed. Biological assays based on biolistic inoculations showed that BBSV induced leaf roll and stunting symptoms similar to those observed in the field-collected common bean sample. [ABSTRACT FROM AUTHOR]

The genus Carlavirus (family Betaflexiviridae, order Tymovirales) currently includes 53 species recognized by the ICTV. The NCBI GenBank database has 43 full-length carlavirus genome sequences (7,890 to 9,073 nt). Surprisingly, the type species Carnation latent virus is not associated with a complete genome sequence of a carnation latent virus (CLV) isolate; GenBank only has accessions with 1313 or fewer nucleotides. The goal of this study was to determine the full-length genome sequence of CLV. Naturally infected greenhouse-grown 'Kiwi Lace' carnation plants that tested positive for CLV by ELISA and RT-PCR were used as source plants for high-throughput sequencing, completed by 5' and 3' RACE and validated by Sanger sequencing of CLV-specific RT-PCR-generated amplicons. The complete CLV-KL sequence (MN450069) was determined to be 8,513 nt in length. In pairwise analysis, the genome shares 40-46% identity with recognized carlaviruses and the six in silico-translated proteins have 15-62% amino acid sequence identity to their respective carlavirus orthologs. The CLV-KL coat protein shares 98.4% identity with the NCBI reference sequence CLV-UK. In phylogenetic analysis, CLV clusters with butterbur mosaic virus, coleus vein necrosis virus, and garlic common latent virus. This is the first report of the full genome sequence of an isolate of carnation latent virus, the type member of the genus Carlavirus. [ABSTRACT FROM AUTHOR]

A new badnavirus, aucuba ringspot virus (AuRV), was identified in plants of Aucuba japonica showing mild mosaic, vein banding, and yellow ringspot symptoms on the leaves. The complete nucleotide sequence of the AuRV genome was determined and found to be 9,092 nt in length, and the virus was found to have a genome organization typical of members of the genus Badnavirus. ORF3 was predicted to encode a polyprotein containing conserved movement protein, coat protein, aspartic protease, reverse transcriptase (RT), and RNase H domains. Phylogenetic analysis suggested that this virus is most closely related to codonopsis vein clearing virus but belongs to a distinct species, based on only 69.6% nucleotide sequence identity within the part of ORF 3 encoding the RT and RNase H domains. The vector of AuRV is unknown, but based on phylogenetic relationships, it is predicted to be a type of aphid. [ABSTRACT FROM AUTHOR]

In this study, we report the complete genome sequence of swinepox virus from a clinical sample from a naturally occurring infection in India. The sequencing was done on a Nanopore MinION sequencer from Oxford Nanopore Technologies. Two new annotations were added to the genome. Three of the genes were found to have frameshifts, which might be of importance in relation to infection. When compared to the only other reported whole genome sequence of swinepox virus, which was obtained from an isolate from America in 1999, our sequence is only 98.19% identical at the nucleotide level. The average amino acid sequence identity of the viral proteins, based on the common 149 annotations, is also 98.19%, demonstrating that these viruses are distinctly divergent. Owing to the fact that swinepox virus infects only swine, it could not have entered America until the introduction of swine in the 16th century from Europe. The swinepox viruses in both continents have continued to evolve independently. The sequence divergence identified here indicates a Eurasian-lineage virus that is geographically distinct from the American-lineage swinepox virus. [ABSTRACT FROM AUTHOR]

RNA was extracted from 'Hugh Dickson' rose leaves displaying virus-like symptoms in Maryland, USA. Using high-throughput sequencing, we identified a new virus, tentatively named "rose virus R". This virus has a negative-sense, single-stranded RNA genome and exhibits genomic features of a rhabdovirus, including a genome organization of 3'–N–P–P3–M–G–P6–L–5' and a gene junction region consensus sequence 3'-AUUUAUUUUGACUCUA-5'. Rose virus R is phylogenetically related to cytorhabdoviruses, and the nucleotide and amino acid sequences of rose virus R and related cytorhabdoviruses have diverged considerably, suggesting that rose virus R should be classified as a member of a novel species in the genus Cytorhabdovirus. [ABSTRACT FROM AUTHOR]

Enterovirus 71 (EV71) is a causative agent of hand, foot and, mouth disease (HFMD) in young children. It is valuable for virologists to develop a fast method to rescue infectious virus from a viral cDNA clone. Here, we report a method for rapid rescue of infectious EV71 by using cells expressing T7 polymerase. The full-length EV71 genome was amplified in one step by long-distance PCR with a T7 promoter at the 5ʹ end, and the T7 polymerase gene was cloned into a lentivirus vector for construction of a stable cell line expressing T7 polymerase. The infectious virus was rapidly and efficiently rescued by single transfection of cells with the infectious cDNA clone. Further experiments showed that the rescued virus had characteristics similar to those of the parental virus. This method circumvented the difficulty in performing in vitro transcription of a long linear DNA to obtain high-quality RNA. The construction of the viral cDNA clone and the fast rescue of the infectious virus will greatly benefit future investigations. [ABSTRACT FROM AUTHOR]

The bisegmented genome of a novel double-stranded (ds) RNA mycovirus, named "Aspergillus nidulans partitivirus 1" (AnPV1), isolated from the fungus Aspergillus nidulans strain HJ5-47, was sequenced and analyzed. AnPV1 contains two segments, AnPV1-1 and AnPV1-2. AnPV1-1 has 1837 bp with an open reading frame (ORF) that potentially encodes a putative RNA-dependent RNA polymerase (RdRp) of 572 amino acids (aa). AnPV1-2 has 1583 bp with an ORF encoding a putative capsid protein (CP) of 488 aa. Phylogenetic analyses indicated that AnPV1 and related viruses clustered in a group that could represent a new unclassified genus in the family Partitiviridae. [ABSTRACT FROM AUTHOR]

Mayaro fever is an infection caused by Mayaro virus (MAYV) that stands out among the neglected diseases transmitted by arthropods. Brazil is the country with the highest number of confirmed cases of MAYV infection. However, epidemiological surveillance studies conducted in Brazil are decentralized and focus on small outbreaks and unconfirmed cases. Thus, the aim of this review was to determine the general epidemiological profile of MAYV infections in Brazil. Several medical databases (i.e., PUBMED/MEDLINE, Scopus, Cochrane Library, LILACS, SciELO, and Biblioteca Virtual em Saúde) were searched for studies reporting cases of MAYV infections in Brazilian patients. Then, the rate of exposure to MAYV in Brazil was analyzed using RStudio® Software. We identified 37 studies published from 1957 to 2019, containing data of 12,374 patients from 1955 to 2018. The general rate of exposure to MAYV in Brazil was 10% (95% CI; 0.04-0.22), with 1,304 reported cases. The highest incidence of MAYV infection was found in the northern region (13%; 95% CI; 0.05-0.29), with 1,142 cases (88% of all cases). Furthermore, autochthonous MAYV cases have also been reported in the Central West (8%; 95% CI; 0.03-0.18) and Southeast (0.4%; 95% CI; 0.00-0.28). The states with the highest number of cases are Amazonas (490 cases), Pará (276 cases), and Goiás (87 cases). In conclusion, the general rate of exposure to MAYV in Brazil between 1955 and 2018 was considerable, especially in the Legal Amazon, in which 93% of cases were reported. [ABSTRACT FROM AUTHOR]

Pseudocowpox is a zoonosis caused by pseudocowpox virus (PCPV), which mainly affects cows but can be an occupational disease of humans. The aim of the study was to validate a quantitative polymerase chain reaction (qPCR) assay for the detection of PCPV. The assay was able to detect up to 1000 copies of PCPV per µL in field samples, with a sensitivity of 80% and a specificity of 100%. We did not observe any cross-reactivity between PCPV-positive samples and samples that were positive for other genetically similar viruses. The repeatability and reproducibility were adequate according to parameters preestablished in official test validation manuals. [ABSTRACT FROM AUTHOR]

The infectivity of shrew-borne hantaviruses to humans is still unclear because of the lack of a serodiagnosis method for these viruses. In this study, we prepared recombinant nucleocapsid (rN) proteins of Seewis orthohantavirus, Altai orthohantavirus (ALTV), Thottapalayam thottimvirus (TPMV), and Asama orthohantavirus. Using monospecific rabbit sera, no antigenic cross-reactivity was observed. In a serosurvey of 104 samples from renal patients and 271 samples from heathy controls from Sri Lanka, one patient serum and two healthy control sera reacted with rN proteins of ALTV and TPMV, respectively. The novel assays should be applied to investigate potential infectivity of shrew-borne hantaviruses to humans. [ABSTRACT FROM AUTHOR]

Deformed wing virus (DWV) is an emerging honeybee pathogen that has appeared across the globe in the past 40 years. When transmitted by the parasitic varroa mite, it has been associated with the collapse of millions of colonies throughout the Northern Hemisphere. However, despite the presence of the mite in the Southern Hemisphere, infested colonies survive. This study investigated the prevalence of DWV genotypes A, B and C along with their viral loads in South Africa and compared the findings with recent data from Brazil, the UK and the USA. We found that DWV-B was the most prevalent genotype throughout South Africa, although the total DWV viral load was significantly lower (2.8E+07) than found in the Northern Hemisphere (2.8E+07 vs. 2.7E+10, p > 0.00001) and not significantly different to that found in Brazil (5E+06, p = 0.13). The differences in viral load can be explained by the mite resistance in Brazil and South Africa, since mite-infested cells containing high viral loads are removed by the bees, thus lowering the colony's viral burden. This behaviour is much less developed in the vast majority of honeybees in the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

In this study, we analyzed the viral population in oropharyngeal samples from T. brasiliensis using a viral metagenomic approach. Genomes corresponding to members of the families Circoviridae, Genomoviridae, Herpesviridae, Paramyxoviridae, Coronaviridae, and Astroviridae were detected. This study provides the first preliminary understanding of the oropharyngeal virome of T. brasiliensis, which may guide the discovery and isolation of novel viruses in the future and highlights the need for continuing investigations in this regard. [ABSTRACT FROM AUTHOR]

On several occasions over the past century it has been proposed that Latinized (Linnaean) binomial names (LBs) should be used for the formal names of virus species, and the opinions expressed in the early debates are still valid. The use of LBs would be sensible for the current Taxonomy if confined to the names of the specific and generic taxa of viruses of which some basic biological properties are known (e.g. ecology, hosts and virions); there is no advantage in filling the literature with formal names for partly described viruses or virus-like gene sequences. The ICTV should support the time-honoured convention that LBs are only used with biological (phylogenetic) classifications. Recent changes have left the ICTV Taxonomy and its Code uncoordinated, and its aims and audience uncertain. [ABSTRACT FROM AUTHOR]

In this study, we present an analysis of metagenome sequences obtained from a filtrate of a siphon tissue homogenate of otter clams (Lutraria rhynchaena) with swollen-siphon disease. The viral signal was mined from the metagenomic data, and a novel circular ssDNA virus was identified. Genomic features and phylogenetic analysis showed that the virus belongs to the phylum Cressdnaviricota, which consists of viruses with circular, single-stranded DNA (ssDNA) genomes. Members of this phylum have been identified in various species and in environmental samples. The newly found virus is distantly related to the currently known members of the phylum Cressdnaviricota. [ABSTRACT FROM AUTHOR]

Minute virus of canines (MVC) belongs to the family Parvoviridae, genus Bocaparvovirus, and has been mainly described during enteritis episodes in young dogs. This study reports the characterization of four divergent MVC strains detected between 2012 and 2018, three of which were from dogs illegally imported into Italy, most probably from Eastern Europe, that cluster together phylogenetically but share low genetic similarity with the fourth MVC from an autochthonous dog and other available MVC sequences. Our data indicate that the introduction of genetically distinct MVC strains occurred through the illegal movement of dogs from a geographic area where a distinct MVC lineage was most likely circulating. Enforced surveillance of MVC in the dog population of Eastern Europe and its neighboring countries may shed light on, and eventually trace back to, illegal animal movements. [ABSTRACT FROM AUTHOR]

The species concept used in virology is based on the logic of the Linnaean hierarchy, which views a species class as the lowest abstract category that is included in all the higher categories in the classification, such as genera and families. As a result of this class inclusion, the members of a species class are always less numerous than the members of higher classes, which become more numerous as one moves up in the hierarchy. Because species classes always have fewer members than any of the higher classes, logic requires that they need more qualifications for establishing membership than any of the higher classes. This invalidates the claim that a species could be defined by a single property present in all its members. Species were only accepted in virus classification in 1991, because virologists assumed that it would lead to the use of Latin species names, which they rejected. Anglicized binomial species names have been used by virologists for more the 40 years and are popular because they consist of a virus name followed by a genus name that most virologists are familiar with. The ICTV has proposed to introduce a new Latinized virus species binomial nomenclature using the genus name followed by a hard-to-remember Latinized species epithet that bears little resemblance to the name of the virus itself. However, the proposal did not clarify what the advantage is of having to learn hundreds of new unfamiliar virus species names. In 2013, the ICTV changed the definition of a virus species as an abstract class and defined it as a group of physical objects, which induced virologists to believe that a virus species could be defined by a few characteristics of the viral genome. In recent years, thousands of viral sequences have been discovered in metagenomic databases, and the ICTV has suggested that it should be possible to incorporate these sequences in the current ICTV virus classification. Unfortunately, the relational properties of these hypothetical viruses that result from their biological interactions with hosts and vectors remain in the vast majority of cases totally unknown. The absence of this information makes it in fact impossible to incorporate these metagenomic sequences in the current classification of virus species. [ABSTRACT FROM AUTHOR]