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Voprosy Virusologii Dec 2023Bastroviruses were discovered in the Netherlands in 2016 in human stool samples and show partial genetic similarities to astroviruses and hepatitis E viruses. Their...
INTRODUCTION
Bastroviruses were discovered in the Netherlands in 2016 in human stool samples and show partial genetic similarities to astroviruses and hepatitis E viruses. Their association with disease onset has not yet been established.
MATERIALS AND METHODS
Metagenomic sequencing of fecal samples of bats collected in the Russian Federation in 2023 was performed. Two almost complete genomes of bastroviruses were assembled. The zoonotic potential of these viruses was assessed using machine learning methods, their recombination was studied, and phylogenetic trees were constructed.
RESULTS
A nearly complete bastrovirus genome was de novo assembled in one of the samples, and it was used to assemble another genome in another sample. The zoonotic potential of the virus from one of these samples was estimated as high. The existence of recombination between structural and non-structural polyproteins was demonstrated.
CONCLUSION
Two bastrovirus genomes were assembled, phylogenetic and recombination analyses were performed, and the zoonotic potential was evaluated.
Topics: Animals; Humans; Astroviridae; Astroviridae Infections; Phylogeny; Chiroptera; Genetic Variation
PubMed: 38156566
DOI: 10.36233/0507-4088-192 -
PLoS Biology Jul 2023During the last decade, the detection of neurotropic astroviruses has increased dramatically. The MLB genogroup of astroviruses represents a genetically distinct group...
During the last decade, the detection of neurotropic astroviruses has increased dramatically. The MLB genogroup of astroviruses represents a genetically distinct group of zoonotic astroviruses associated with gastroenteritis and severe neurological complications in young children, the immunocompromised, and the elderly. Using different virus evolution approaches, we identified dispensable regions in the 3' end of the capsid-coding region responsible for attenuation of MLB astroviruses in susceptible cell lines. To create recombinant viruses with identified deletions, MLB reverse genetics (RG) and replicon systems were developed. Recombinant truncated MLB viruses resulted in imbalanced RNA synthesis and strong attenuation in iPSC-derived neuronal cultures confirming the location of neurotropism determinants. This approach can be used for the development of vaccine candidates using attenuated astroviruses that infect humans, livestock animals, and poultry.
Topics: Child; Animals; Humans; Child, Preschool; Aged; Mamastrovirus; Astroviridae Infections; Gastroenteritis; Capsid Proteins; Capsid; Phylogeny
PubMed: 37459343
DOI: 10.1371/journal.pbio.3001815 -
Mucosal Immunology Aug 2023Astroviruses cause a spectrum of diseases spanning asymptomatic infections to severe diarrhea, but little is understood about their pathogenesis. We previously...
Astroviruses cause a spectrum of diseases spanning asymptomatic infections to severe diarrhea, but little is understood about their pathogenesis. We previously determined that small intestinal goblet cells were the main cell type infected by murine astrovirus-1. Here, we focused on the host immune response to infection and inadvertently discovered a role for indoleamine 2,3-dioxygenase 1 (Ido1), a host tryptophan catabolizing enzyme, in the cellular tropism of murine and human astroviruses. We identified that Ido1 expression was highly enriched among infected goblet cells, and spatially corresponded to the zonation of infection. Because Ido1 can act as a negative regulator of inflammation, we hypothesized it could dampen host antiviral responses. Despite robust interferon signaling in goblet cells, as well as tuft cell and enterocyte bystanders, we observed delayed cytokine induction and suppressed levels of fecal lipocalin-2. Although we found Ido animals were more resistant to infection, this was not associated with fewer goblet cells nor could it be rescued by knocking out interferon responses, suggesting that IDO1 instead regulates cell permissivity. We characterized IDO1 Caco-2 cells and observed significantly reduced human astrovirus-1 infection. Together this study highlights a role for Ido1 in astrovirus infection and epithelial cell maturation.
Topics: Animals; Humans; Mice; Astroviridae Infections; Caco-2 Cells; Indoleamine-Pyrrole 2,3,-Dioxygenase; Interferons; Tryptophan
PubMed: 37290501
DOI: 10.1016/j.mucimm.2023.05.011 -
The Veterinary Record Jul 2023
Topics: Animals; Geese; Avastrovirus; Poultry Diseases; Astroviridae Infections; Phylogeny; China
PubMed: 37477330
DOI: 10.1002/vetr.3297 -
Scientific Reports Jun 2023Novel goose astrovirus (NGAstV) is a member of the genus Avain Avastrovirus (AAstV) and the family Astroviridae. NGAstV-associated gout disease has caused huge economic...
Novel goose astrovirus (NGAstV) is a member of the genus Avain Avastrovirus (AAstV) and the family Astroviridae. NGAstV-associated gout disease has caused huge economic losses to the goose industry worldwide. Since early 2020, NGAstV infections characterized by articular and visceral gout emerged continuously in China. Herein, we isolated a GAstV strain from goslings with fatal gout disease and sequenced its complete genome nucleotide sequence. Then we conducted systematic genetic diversity and evolutionary analysis. The results demonstrated that two genotypic species of GAstV (GAstV-I and GAstV-II) were circulating in China, and GAstV-II sub-genotype IId had become the dominant one. Multiple alignments of amino acid sequences of GAstV capsid protein revealed that several characteristic mutations (E456D, A464N, and L540Q) in GAstV-II d strains, as well as additional residues in the newly identified isolate which varied over time. These findings enrich the understanding of the genetic diversity and evolution of GAstV and may facilitate the development of effective preventive strategies.
Topics: Animals; Geese; Avastrovirus; Genomics; Arthritis, Gouty; Gout; China
PubMed: 37386083
DOI: 10.1038/s41598-023-37784-9 -
Microbial Pathogenesis Aug 2023Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to... (Meta-Analysis)
Meta-Analysis Review
AIM
Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to conduct a meta-analytic review of the prevalence of HAstV amongst patients with gastroenteritis, and to shed light on the connection between HAstV infection and gastroenteritis.
METHODS
Systematic literature searches were conducted to identify all potentially relevant studies recorded up to April 8th, 2022. For study weighting, the inverse variance method was employed and the random-effects model was applied to evaluate data. For case-control studies, the pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to establish the relationship between HAstV infection and gastroenteritis.
RESULTS
Among 302423 gastroenteritis patients from 69 different countries, the overall pooled prevalence of HAstV infection was 3.48% (95% CI: 3.11%-3.89%). Case-control approach was used in 39 investigations, and the overall prevalence of HAstV infection among the 11342 healthy controls was 2.01% (95% CI: 1.40%-2.89%). Gastroenteritis and HAstV infection were associated with a pooled OR of 2.16 (95% CI: 1.72-2.71; P < 0.0001; I = 33.7%). The most commonly found HAstV genotypes in gastroenteritis patients were HAstV1 (62.18%), HAstV7 (33.33%), and HAstV-MLB1 (17.43%).
CONCLUSION
The frequency of HAstV infection was the highest in children under the age of five, and in developing countries. The prevalence rate of HAstV was not influenced by gender. Semi-nested and nested RT-PCR were highly sensitive assays for detecting HAstV infections.
Topics: Child; Humans; Infant; Child, Preschool; Aged; Mamastrovirus; Prevalence; Phylogeny; Feces; Gastroenteritis; Astroviridae Infections; Genotype
PubMed: 37385570
DOI: 10.1016/j.micpath.2023.106209 -
Viruses Aug 2023Astroviruses (AstV) and adenoviruses (AdV) are associated with diarrhoea in young animals. However, the epidemiology and genetic diversity of AstVs and AdVs in animals...
Astroviruses (AstV) and adenoviruses (AdV) are associated with diarrhoea in young animals. However, the epidemiology and genetic diversity of AstVs and AdVs in animals is not well studied. Hence, the present study was conducted to detect and characterize AstVs and AdVs in calves, piglets and puppies from Western Maharashtra, India. Out of the processed porcine (48), canine (80), and bovine (65) faecal samples, the porcine AstV (PAstV), bovine AstV (BAstV), canine AstV (CAstV), and porcine AdV (PAdV) were detected in 12.5%, 7.69%, 3.75% and 4.1% of samples, respectively. In the RNA-dependent RNA polymerase region-based phylogenetic analysis, the detected BAstV strains grouped with MAstV-28, MAstV-33, and MAstV-35, CAstV strains belonged to MAstV-5; PAstV strains belonged to MAstV-24, MAstV-26, and MAstV-31. However, in hexon gene-based phylogeny, both the detected PAdV were of genotype 3, exhibiting 91.9-92.5% nucleotide identity with Ivoirian and Chinese strains. The study reports first-time BAstVs from calves and PAdV-3 from piglets in India. The study revealed diversity in the circulation of AstVs in tested animals and AdVs in pigs, and suggested that they alone might be associated with other diarrhoea or in combination with other enteric pathogens, thus highlighting the necessity of extensive epidemiological investigations to develop diagnostic tools and control measures.
Topics: Animals; Cattle; Dogs; Swine; Adenoviridae; Phylogeny; India; Adenoviridae Infections; Astroviridae; Canidae; Diarrhea
PubMed: 37632021
DOI: 10.3390/v15081679 -
Journal of Virology Sep 2023Human astrovirus is a positive-sense, single-stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised...
Human astrovirus is a positive-sense, single-stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised patients. Positive-strand RNA viruses typically utilize host intracellular membranes to form replication organelles, which are potential antiviral targets. Many of these replication organelles are double-membrane vesicles (DMVs). Here, we show that astrovirus infection leads to an increase in DMV formation through a replication-dependent mechanism that requires some early components of the autophagy machinery. Results indicate that the upstream class III phosphatidylinositol 3-kinase (PI3K) complex, but not LC3 conjugation machinery, is utilized in DMV formation. Both chemical and genetic inhibition of the PI3K complex lead to significant reduction in DMVs, as well as viral replication. Elucidating the role of autophagy machinery in DMV formation during astrovirus infection reveals a potential target for therapeutic intervention for immunocompromised patients. IMPORTANCE These studies provide critical new evidence that astrovirus replication requires formation of double-membrane vesicles, which utilize class III phosphatidylinositol 3-kinase (PI3K), but not LC3 conjugation autophagy machinery, for biogenesis. These results are consistent with replication mechanisms for other positive-sense RNA viruses suggesting that targeting PI3K could be a promising therapeutic option for not only astrovirus, but other positive-sense RNA virus infections.
Topics: Humans; Autophagy; Class III Phosphatidylinositol 3-Kinases; Intracellular Membranes; Organelles; Phosphatidylinositol 3-Kinase; RNA Viruses; Virus Replication; Mamastrovirus; Signal Transduction
PubMed: 37668367
DOI: 10.1128/jvi.01025-23 -
Research in Veterinary Science Aug 2023Astroviruses have been identified in a wide variety of animal species and are associated with gastro-intestinal disease in humans. Pathologies due to extra-intestinal...
Astroviruses have been identified in a wide variety of animal species and are associated with gastro-intestinal disease in humans. Pathologies due to extra-intestinal localization are known in different hosts. We report the detection of astroviruses in synanthropic squamate reptile species (Podercis siculus and Tarentola mauritanica). Fecal samples were collected from 100 squamates from urban and peri-urban areas of three regions in South Italy and tested for the presence of astroviruses using a broadly reactive (pan-astrovirus) RT-PCR protocol targeting the RNA-dependent RNA polymerase. Astrovirus RNA was detected in 11% of the samples and for six strains a 3 kb-long fragment at the 3' end of the genome was sequenced, obtaining information on the complete capsid-encoding ORF2 sequence. Viral RNA was also detected in the brain of one of the positive animals. The sequences generated from the astrovirus strains shared low nucleotide identities in the ORF2 (< 43.7%) with other known reptilian astrovirus sequences, hinting to the massive genetic diversity of members of this viral family. Based on the partial RdRp gene of the sequenced strains, however, we observed species-specific patterns, regardless of the geographic origin of the animals, and we also identified a possible inter-species transmission event between geckoes and lizards.
Topics: Humans; Animals; Astroviridae Infections; Astroviridae; RNA Viruses; RNA, Viral; Genome, Viral; Phylogeny
PubMed: 37331242
DOI: 10.1016/j.rvsc.2023.06.009 -
Veterinary Research Dec 2023It is well-established that the genetic diversity, regional prevalence, and broad host range of astroviruses significantly impact the poultry industry. In July 2022, a...
It is well-established that the genetic diversity, regional prevalence, and broad host range of astroviruses significantly impact the poultry industry. In July 2022, a small-scale commercial broiler farm in China reported cases of growth retardation and a 3% mortality rate. From chickens displaying proventriculitis and pancreatitis, three chicken astroviruses (CAstV) isolates were obtained and named SDAU2022-1-3. Complete genomic sequencing and analysis revealed the unique characteristics of these isolates from known CAstV strains in ORF1a, ORF1b, and ORF2 genes, characterized by an unusually high variability. Analysis of amino acid mutations in ORF1a, ORF1b, and ORF2 indicated that the accumulation of these mutations played a pivotal role in the emergence of the variant strain. Inoculation experiments demonstrated that affected chickens exhibited liver and kidney enlargement, localized proventricular hemorrhage, and a dark reddish-brown appearance in about two-thirds of the pancreas. Histopathological examination unveiled hepatic lymphocytic infiltration, renal tubular epithelial cell swelling, along with lymphocytic proventriculitis and pancreatitis. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated viremia and viral shedding at 3 days post-infection (dpi). The proventriculus displayed the highest viral loads, followed by the liver, kidney, duodenum, and pancreas. Liver parameters (AST and ALT) and kidney parameters (UA and UN) demonstrated mild damage consistent with earlier findings. While the possibility of new mutations in the ORF2 gene of CAstV causing proventriculitis and pancreatitis warrants further investigation, these findings deepen our comprehension of CAstV's pathogenicity in chickens. Additionally, they serve as valuable references for subsequent research endeavors.
Topics: Animals; Avastrovirus; Chickens; Virulence; Astroviridae Infections; Pancreatitis; Poultry Diseases; Phylogeny
PubMed: 38066626
DOI: 10.1186/s13567-023-01250-1