RESUMEN
Wild waterfowl serve as a reservoir of some astroviruses. Fecal samples from wild waterfowl collected at Hong Kong's Marshes were tested using pan-astrovirus reverse transcription-PCR. Positive samples underwent subsequent host identification using DNA barcoding. Based on deduced partial sequences, noteworthy samples from three astrovirus groups (mammalian, avian and unclassified astroviruses) were further analyzed by next-generation sequencing. One sample of Avastrovirus 4 clade, MP22-196, had a nearly complete genome identified. The results of ORF2 phylogenetic analysis and genetic distance analysis indicate that Avastrovirus 4 is classified as a distinct subclade within Avastrovirus. MP22-196 has typical astrovirus genome characteristics. The unique characteristics and potential differences of this genome, compared to other avian astrovirus sequences, involve the identification of a modified sgRNA sequence situated near the ORF2 start codon, which precedes the ORF1b stop codon. Additionally, the 3' UTR of MP22-196 is shorter than other avian astroviruses. This study expands our understanding of the Avastrovirus 4 clade.
Asunto(s)
Infecciones por Astroviridae , Aves , Heces , Variación Genética , Genoma Viral , Filogenia , Animales , Hong Kong , Aves/virología , Heces/virología , Infecciones por Astroviridae/veterinaria , Infecciones por Astroviridae/virología , Animales Salvajes/virología , Enfermedades de las Aves/virología , Secuenciación de Nucleótidos de Alto Rendimiento , Avastrovirus/genética , Avastrovirus/clasificación , Avastrovirus/aislamiento & purificación , ARN Viral/genética , Sistemas de Lectura Abierta , Astroviridae/genética , Astroviridae/aislamiento & purificación , Astroviridae/clasificaciónRESUMEN
Goose astrovirus genotype 1 (GAstV-1) has emerged in goose farms in some provinces of China in recent years and is considered to be one of the pathogens of gout in goslings in China. However, few studies have been conducted on the dynamic distribution, tissue tropism, and pathogenesis of GAstV-1 in goslings. In 2022, an epidemiological investigation of goose astrovirus (GAstV) in goslings was conducted in seven provinces of China. During the investigation, a GAstV-1 designated as GAstV-JSXZ was identified in the kidney of an 8-day-old gosling and was successfully isolated from a goose embryo. The full genome sequence of GAstV-JSXZ was determined using the next-generation sequencing technique. The complete genome of GAstV-JSXZ was 7299-nt-long. Interestingly, the phylogenetic analysis revealed that Chinese GAstV-1 has formed two distinct subgroups based on the ORF 2 genomes, designated GAstV-1 1a and GAstV-1 1b. The GAstV-JSXZ shared the highest identity with GAstV-1 1a strain FLX and TZ03 in nucleotides (ORF1a: 98.3-98.4%; ORF1b: 92.3-99.1%; ORF2: 95.8-98.8%) and amino acid sequences (ORF1a: 99.4-99.5%; ORF1b: 98.2-98.8%; ORF2: 97.0-99.4%). To evaluate the pathogenicity of GAstV-1, 1-day-old goslings were inoculated with the virus by oral and subcutaneous injection routes, respectively. The results revealed that the virus causes extensive pathological organ damage, especially in the kidney, liver, and thymus. Virus-specific genomic RNA could be detected in the cloacal swabs and tissues of infected goslings throughout the experiment. The viral copy numbers examined in the kidney and intestine were the highest, followed by the liver and spleen. These results are likely to provide a new understanding of the pathogenicity of GAstV-1 in geese.
Asunto(s)
Infecciones por Astroviridae , Gansos , Genoma Viral , Genotipo , Filogenia , Enfermedades de las Aves de Corral , Animales , Gansos/virología , China , Infecciones por Astroviridae/veterinaria , Infecciones por Astroviridae/virología , Enfermedades de las Aves de Corral/virología , Astroviridae/genética , Astroviridae/aislamiento & purificación , Astroviridae/clasificación , Astroviridae/patogenicidad , Avastrovirus/genética , Avastrovirus/aislamiento & purificación , Avastrovirus/clasificación , Avastrovirus/patogenicidad , Virulencia , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
The emergence of a novel goose nephritic astrovirus (GNAstV) has caused economic losses to the Chinese goose industry. High viral load is found in the spleen of goslings infected with GNAstV, but pathological injuries to the spleen due to GNAstV are largely unknown. In this study, 50 two-day-old goslings were infected orally with GNAstV, and 50 goslings were treated with PBS as control. Spleens were collected at different times following infection to assess damage. GNAstV infection caused visceral gout and urate deposition in joints, and resulted in 16% mortality. GNAstV was found in the lymphocytes and macrophages within the spleen. Lymphocyte loss, especially around the white pulp, and destruction and decline in the number of reticular fibers was observed in GNAstV-infected goslings. Moreover, in GNAstV-infected goslings, ultrahistopathological examination found that splenic lymphocytes exhibited condensed chromatin and apoptotic bodies, and reticular cells displayed damage to plasma membrane integrity and swollen mitochondria. Furthermore, TUNEL staining confirmed apoptosis of lymphocytes, and the mRNA levels of Fas and FasL were significantly increased in the GNAstV-infected goslings. In addition, GNAstV infection reduced the number and protein expression of CD8. In conclusion, GNAstV infection causes lymphocyte depletion, reticular cell necrosis, reticular fiber destruction, lymphocyte apoptosis, and reduction in CD8 levels, which contribute to spleen injury.
Asunto(s)
Apoptosis , Avastrovirus/fisiología , Gansos/virología , Linfocitos/metabolismo , Enfermedades de las Aves de Corral/etiología , Enfermedades de las Aves de Corral/metabolismo , Animales , Avastrovirus/clasificación , Avastrovirus/genética , Biopsia , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos , Inmunohistoquímica , Recuento de Linfocitos , Linfocitos/inmunología , Linfocitos/patología , Enfermedades de las Aves de Corral/diagnóstico , Bazo/inmunología , Bazo/metabolismo , Bazo/patología , Bazo/virología , Carga ViralRESUMEN
Avian nephritis virus (ANV) is classified in the Avastroviridae family with disease associations with nephritis, uneven flock growth and runting stunting syndrome (RSS) in chicken and turkey flocks, and other avian species. The whole genome of ANV genotype 3 (ANV-3) of 6959 nucleotides including the untranslated 5' and 3' regions and polyadenylated tail was detected in a metagenomic virome investigation of RSS-affected chicken broiler flocks. This report characterises the ANV-3 genome, identifying partially overlapping open reading frames (ORFs), ORF1a and ORF1b, and an opposing secondary pseudoknot prior to a ribosomal frameshift stemloop structure, with a separate ORF2, whilst observing conserved astrovirus motifs. Phylogenetic analysis of the Avastroviridae whole genome and ORF2 capsid polyprotein classified the first complete whole genome of ANV-3 within Avastroviridae genogroup 2.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/genética , Genoma Viral , Enfermedades de las Aves de Corral/virología , Animales , Infecciones por Astroviridae/virología , Avastrovirus/química , Avastrovirus/clasificación , Avastrovirus/aislamiento & purificación , Secuencia de Bases , Pollos , Genotipo , Conformación de Ácido Nucleico , Sistemas de Lectura Abierta , Filogenia , ARN Viral/química , ARN Viral/genética , PavosRESUMEN
In this study, we aimed to molecularly characterize 14 whole genome sequences of chicken astrovirus (CAstV) isolated from samples obtained from white chick syndrome (WCS) outbreaks in Western Canada during the period of 2014-2019. Genome sequence comparisons showed all these sequences correspond to the novel Biv group from which no confirmed representatives were published in GenBank. Molecular recombination analyses using recombination detection software (i.e., RDP5 and SimPlot) and phylogenetic analyses suggest multiple past recombination events in open reading frame (ORF)1a, ORF1b, and ORF2. Our findings suggest that recombination events and the accumulation of point mutations may have contributed to the substantial genetic variation observed in CAstV and evidenced by the current seven antigenic sub-clusters hitherto described. This is the first paper that describes recombination events in CAstV following analysis of complete CAstV sequences originated in Canada.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Infecciones por Astroviridae/virología , Avastrovirus/genética , Pollos/virología , Enfermedades de las Aves de Corral/virología , Recombinación Genética , Animales , Infecciones por Astroviridae/epidemiología , Infecciones por Astroviridae/patología , Avastrovirus/clasificación , Secuencia de Bases , Canadá/epidemiología , Genoma Viral , Genotipo , Hígado/patología , Epidemiología Molecular , Sistemas de Lectura Abierta , Filogenia , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/patologíaRESUMEN
In 2019, a new type of infectious disease characterized with haemorrhage and swellings of kidneys, occurred on commercial duck farms in Shandong province, China. Our systematic investigation led to the isolation of an astrovirus, designated AstV-SDTA strain and was isolated from a diseased duckling using LMH cells. Similar clinical symptoms were reproduced by experimental infection using the AstV-SDTA strain. The complete genome sequencing characterization of AstV-SDTA was conducted using next-generation sequencing (NGS) technique on Illumina HiSeq platform, and used polymerase chain reaction method to verify the NGS results for the obtained whole sequences. Phylogenetic analysis revealed that AstV-SDTA strain belongs to a novel goose astrovirus (GoAstV) branch of avian astroviruses, and the nucleotide homology based on the complete genome sequences among AstV-SDTA and other GoAstV strains deposited in Genbank was 97.2-98.8%. Taken together, these results suggest that the cross-species transmission of novel GoAstV between domestic waterfowl is possible. Further surveillance of novel GoAstV in poultry are needed in order to gain a better understanding of both the molecular and evolutionary characteristics of novel GoAstV.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/clasificación , Avastrovirus/aislamiento & purificación , Patos/virología , Gansos/virología , Enfermedades de las Aves de Corral/virología , Animales , Infecciones por Astroviridae/epidemiología , Avastrovirus/patogenicidad , China/epidemiología , Genoma Viral , Secuenciación de Nucleótidos de Alto Rendimiento , Riñón/patología , Riñón/virología , Filogenia , Enfermedades de las Aves de Corral/epidemiología , Secuenciación Completa del GenomaRESUMEN
Astroviruses belong to Astroviridae family which includes two main genera: Mamastroviruses that infect mammals, and Avastroviruses that infect avian hosts. Bats and wild birds are considered among the natural reservoirs for astroviruses. Infections in humans are associated with severe gastroenteritis, especially among children. We conducted surveillance for astroviruses in bats, wild birds, and humans in Egypt. Our results indicated relatively high prevalence of astroviruses in those hosts. Phylogenetic analysis revealed diversity of these viruses within hosts. Detected human viruses showed similarity with classic and variant human astroviruses, as well as similarity with animal-origin viruses. Viruses in bats were dispersed, with similarities to other bat viruses as well as other mammalian, including human, viruses. Wild bird viruses varied and were related to other avastroviruses, as well as human astroviruses. Our results indicate that astroviruses are common in bats, wild birds, and humans in Egypt, with a wide gene pool. Potential cross-species transmission may be occurring but should be verified by further surveillance and molecular studies.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Infecciones por Astroviridae/virología , Avastrovirus/genética , Avastrovirus/aislamiento & purificación , Aves/virología , Quirópteros/virología , Animales , Animales Salvajes/virología , Avastrovirus/clasificación , Egipto , Variación Genética , Humanos , Mamíferos/virología , FilogeniaRESUMEN
Avastrovirus-specific antibodies are widely detected in chickens in China. However, there are currently no commercially available vaccines for this group of viruses. To address this issue, we collected 76 tissue samples from Avastrovirus (AAstVs) antibody-positive chickens from farms across eight provinces in China from 2016 to 2018. The samples were then screened for the presence of AAstVs sequences by polymerase chain reaction analysis and a phylogenetic tree was constructed. Specific primers were designed to amplify the whole genome sequences of the viruses from four positive samples, with the genetic characteristics and structures of the resulting genomes then analyzed further. Overall, 42 (55.3 %) of the 76 samples were positive for AAstVs RNA. Phylogenetic analysis along with the ORF1b gene showed that 15 isolates were grouped in AAstV-1 and 27 of them were grouped in AAstV-2. None of the isolates was belonged to AAstV-3. Sequencing and structural analyses revealed that the genomes of the four isolates showed the typical characteristics of AAstVs genomes but were genetically distinct from other AAstVs. The results of this study will contribute to our understanding of the genetic characteristics of AAstVs in China.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/clasificación , Avastrovirus/genética , Genoma Viral , Filogenia , Animales , Infecciones por Astroviridae/epidemiología , Infecciones por Astroviridae/virología , Pollos/virología , China/epidemiología , Patos/virología , Sistemas de Lectura Abierta , Enfermedades de las Aves de Corral/etiología , Enfermedades de las Aves de Corral/virología , Análisis de Secuencia de ADN , Secuenciación Completa del GenomaRESUMEN
Recently, a novel goose astrovirus (N-GoAstV) was discovered in China, with the transmission route of N-GoAstV unclear. In this study, we developed a TaqMan-based real-time RT-PCR (qRT-PCR) assay for the detection of N-GoAstV infection. After the optimization of the qRT-PCR assay conditions, the results demonstrated that the lower limit of detection for N-GoAstV was 33.4 copies/µL. No cross-reactivity was observed with other goose-origin viruses. Intra-assay and inter-assay variability were ≤1.36% and 2.34%, respectively. N-GoAstV was detected in both field samples, embryos and newly hatched goslings by qRT-PCR assay, provided the view that N-GoAstV may be both horizontally and vertically transmitted. The established qRT-PCR method showed high specificity, sensitivity, and reproducibility, which can be used in future investigations on the pathogenesis and epidemiology of N-GoAstV.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/aislamiento & purificación , Enfermedades de las Aves/virología , Gansos/virología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Animales , Infecciones por Astroviridae/virología , Avastrovirus/clasificación , Avastrovirus/genética , China , Sensibilidad y EspecificidadRESUMEN
Astroviruses are widely detected in pigs but their detection in wild boars is rather sporadic. In this study, astroviruses were detected in organ homogenates of wild boars by applying nested reverse transcriptase polymerase chain reaction, and the typing was carried out by phylogenetic analysis. Overall, 30/200 (15.0%) homogenates were positive for astroviruses. Genetic typing revealed that of 13 amplicons analyzed, 8 were typed as porcine astrovirus lineage 2 (PAstV-2), 2 as lineage 4 (PAstV-4), 2 identical sequences were grouped with chicken astrovirus, and 1 sequence belonged to a bat astrovirus lineage. This first identification of chicken and bat astroviruses in wild boars indicates interspecies transmission.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/genética , Enfermedades de los Porcinos/diagnóstico , Animales , Infecciones por Astroviridae/diagnóstico , Infecciones por Astroviridae/virología , Avastrovirus/clasificación , Avastrovirus/aislamiento & purificación , ADN Viral/análisis , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Análisis de Secuencia de ADN/veterinaria , Eslovaquia , Porcinos , Enfermedades de los Porcinos/virologíaRESUMEN
Since 2017, a new type of goose-origin astrovirus (GoAstV) disease occurred in China. This disease can cause joint swelling of sick geese, and the anatomy shows a clear urate precipitation in the viscera. The rate of death or amputation can reach more than 30%, revealing its severe pathogenicity. One novel goose-origin astrovirus strain, designated as CXZ18, was isolated from diseased geese with a fatal infection characterized by visceral urate deposition. Similar clinical anatomy symptoms were partially reproduced by attacking infection of healthy geese. The CXZ18 has no hemagglutination with chicken erythrocyte, only reproduced in goose embryos, not in SPF chicken or duck embryos. The complete genome-encoded three open reading frames (ORFs) of CXZ18 were 7252â¯nt in length. BLAST-based homology analysis of viral complete genome showed that CXZ18 has only 53.0%-61.8% with other classic avian astrovirus from various hosts. Further analysis of ORF 1a, ORF 1b, and ORF 2 genes revealed that the isolate was genetically distinct from known astroviruses and belonged to a distinctive branch of avian astroviruses. To conclude, a naturally occurring novel nephrotic astrovirus, distinguished with all previously reported avian astroviruses, was derived from goose.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/clasificación , Avastrovirus/genética , Gansos/virología , Genoma Viral , Genómica , Enfermedades de las Aves de Corral/virología , Animales , Avastrovirus/ultraestructura , China , Biología Computacional/métodos , Genómica/métodos , Filogenia , Aves de Corral , Enfermedades de las Aves de Corral/diagnósticoRESUMEN
Since early 2016, the Chinese goose industry has experienced severe outbreaks of gout; however, the etiological factor of the disease is still unclear. Here, we investigated the possible involvement of viral infection in the disease. Using sequence-independent PCR amplification, astrovirus sequences were generated from a gout case. Full-length genomic sequencing and sequence analysis of three goose astrovirus (GoAstV) strains revealed that they belong to a new avastrovirus most closely related to viruses classified within species Avastrovirus 3. The GoAstV was detected in 16/16 gout cases collected from two provinces, supporting a pathogenic role for the new avastrovirus.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/genética , Avastrovirus/aislamiento & purificación , Gansos/virología , Gota/veterinaria , Animales , Infecciones por Astroviridae/virología , Avastrovirus/clasificación , Patos , Genoma Viral , Gota/virología , Sistemas de Lectura Abierta , Filogenia , Enfermedades de las Aves de Corral/virología , PavosRESUMEN
Sixty-four cases of white chick syndrome (WCS) in broiler breeders producing affected progeny were reported from seven hatcheries in Ontario, Canada, between 2009 and 2016, with 43 of those originating from two hatcheries owned by a single company. WCS cases were identified by the presence of typical chicks in the hatchery that were generally weak with pale to white down, enlarged abdomens, and occasionally brown wiry fluff on the dorsum of the neck. Affected embryos and chicks had characteristic gross and histologic liver lesions, and livers were positive for chicken astrovirus (CAstV) RNA by real-time reverse transcriptase PCR. Affected broiler breeder flocks experienced egg production drops of 0% to 21% and hatchability drops of 0% to 68.4%. The amino acid sequence of the region encoding the capsid gene of WCS viruses demonstrated all Ontario CAstV to be in Group B, Subgroup Bii.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/aislamiento & purificación , Enfermedades de las Aves de Corral/virología , Animales , Infecciones por Astroviridae/patología , Infecciones por Astroviridae/virología , Avastrovirus/clasificación , Avastrovirus/genética , Avastrovirus/fisiología , Proteínas de la Cápside/genética , Pollos , Femenino , Hígado/patología , Hígado/virología , Ontario , Filogenia , Enfermedades de las Aves de Corral/patologíaRESUMEN
Astroviruses are recognized as a leading cause of gastroenteritis in humans and animals. They are also associated with extra-intestinal diseases, such as hepatitis in ducklings, nephritis in chickens, and encephalitis in cattle. In February 2017, a fatal infection of goslings characterized by visceral urate deposition was reported in the Shandong province, China. Our systematic investigation led to the isolation of an astrovirus, designated AAstV/Goose/CHN/2017/SD01, and similar disease was reproduced by experimental infection of healthy goslings, fulfilling Koch's postulates. The isolated astrovirus replicated well and resulted in 100% mortality of goose embryos. Complete genome sequence analysis revealed that the isolate was genetically distinct from known astroviruses and closely related to members of the avastrovirus genogroup II. Experimental infection showed that the isolate was highly pathogenic in goslings, causing clinical signs, growth repression and in many cases mortality. Histopathological examination indicated that lesions occurred mainly in the kidneys of infected birds. However, virus-specific genomic RNA was detected in all representative tissues, and virus shedding was detected up to 12 days after inoculation, suggesting that the isolate was able to spread systemically and replicate efficiently in vivo. Collectively, our study demonstrates, for the first time, the etiological role of a genetically distinct astrovirus in the fatal infection of goslings.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/genética , Avastrovirus/aislamiento & purificación , Gansos/virología , Gota/veterinaria , Enfermedades de las Aves de Corral/mortalidad , Animales , Animales Domésticos/virología , Infecciones por Astroviridae/epidemiología , Infecciones por Astroviridae/mortalidad , Avastrovirus/clasificación , Avastrovirus/patogenicidad , China/epidemiología , Genoma Viral , Gota/mortalidad , Gota/virología , Filogenia , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/virología , Replicación Viral , Esparcimiento de Virus , Secuenciación Completa del GenomaRESUMEN
Using an ORF1b-based astrovirus-specfic reverse transcription (RT)-PCR assay, a novel astrovirus-like was detected from domestic geese in China. Pairwise comparisons and phylogenetic analyzes suggested that a novel group of goose astrovirus, different with previously known astroviruses in the genus Avastrovirus, was found circulating in geese. This study has expanded our understanding about the role of domestic waterfowls as reservoirs for diverse astroviruses.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/aislamiento & purificación , Gansos/virología , Enfermedades de las Aves de Corral/virología , Animales , Infecciones por Astroviridae/virología , Avastrovirus/clasificación , China , Tipificación Molecular/veterinaria , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinariaRESUMEN
We report the complete genome sequence of a new avastrovirus of goose-origin (FLX). The 7299-nt-long genome consisted of three overlapping open reading frames (ORFs) that were in different reading frames. Pairwise comparisons showed that the FLX genome was 59% identical to its closest relatives and that the levels of amino acid identity shared by FLX with other astroviruses did not exceed 54% in ORF1a, 66% in ORF1b, and 50% in ORF2, respectively. Phylogenetic analysis based on the amino acid sequence of the full-length ORF2 demonstrated that FLX was highly divergent from all other avastroviruses. At the amino acid level the complete capsid region of FLX shared genetic distances of 0.574-0.719 with three official avastrovirus species, suggesting that it can be classified as a member of a novel species in the genus Avastrovirus.
Asunto(s)
Infecciones por Astroviridae/virología , Avastrovirus/clasificación , Gansos/virología , Filogenia , Enfermedades de las Aves de Corral/virología , Animales , Avastrovirus/genética , Avastrovirus/aislamiento & purificación , Proteínas de la Cápside/genética , China , Genoma Viral , Sistemas de Lectura AbiertaRESUMEN
Although a relatively recently emerged virus, identified only in 2004 as a separate species of avian astrovirus, chicken astrovirus (CAstV) has been associated with poor growth of broiler flocks, enteritis and diarrhea and is a candidate pathogen in cases of runting stunting syndrome. More recently CAstV has been implicated in cases of two other diseases of broilers as the sole etiological agent, namely severe kidney disease of young broilers with visceral gout and the "White Chicks" hatchery disease. Examination of the strains of CAstV associated with the two latter diseases reveals they are closely related genetically. This review will discuss the pathogenesis of CAstV in relation to strain diversity and the effects of vertical versus horizontal transmission, virus load, co-infections and age of bird at infection, all factors that may impact upon disease severity.
Asunto(s)
Avastrovirus/clasificación , Avastrovirus/patogenicidad , Variación Genética , Enfermedades de las Aves de Corral/patología , Enfermedades de las Aves de Corral/virología , Animales , Pollos , Transmisión de Enfermedad Infecciosa , Enfermedades de las Aves de Corral/transmisiónRESUMEN
OBJECTIVE: Chicken astroviruses have been known to cause severe disease in chickens leading to increased mortality and "white chicks" condition. Here we aim to characterize the causative agent of visceral gout suspected for astrovirus infection in broiler breeder chickens. METHODS: Total RNA isolated from allantoic fluid of SPF embryo passaged with infected chicken sample was sequenced by whole genome shotgun sequencing using ion-torrent PGM platform. The sequence was analysed for the presence of coding and non-coding features, its similarity with reported isolates and epitope analysis of capsid structural protein. RESULTS: The consensus length of 7513 bp genome sequence of Indian isolate of chicken astrovirus was obtained after assembly of 14,121 high quality reads. The genome was comprised of 13 bp 5'-UTR, three open reading frames (ORFs) including ORF1a encoding serine protease, ORF1b encoding RNA dependent RNA polymerase (RdRp) and ORF2 encoding capsid protein, and 298 bp of 3'-UTR which harboured two corona virus stem loop II like "s2m" motifs and a poly A stretch of 19 nucleotides. The genetic analysis of CAstV/INDIA/ANAND/2016 suggested highest sequence similarity of 86.94% with the chicken astrovirus isolate CAstV/GA2011 followed by 84.76% with CAstV/4175 and 74.48%% with CAstV/Poland/G059/2014 isolates. The capsid structural protein of CAstV/INDIA/ANAND/2016 showed 84.67% similarity with chicken astrovirus isolate CAstV/GA2011, 81.06% with CAstV/4175 and 41.18% with CAstV/Poland/G059/2014 isolates. However, the capsid protein sequence showed high degree of sequence identity at nucleotide level (98.64-99.32%) and at amino acids level (97.74-98.69%) with reported sequences of Indian isolates suggesting their common origin and limited sequence divergence. The epitope analysis by SVMTriP identified two unique epitopes in our isolate, seven shared epitopes among Indian isolates and two shared epitopes among all isolates except Poland isolate which carried all distinct epitopes.
Asunto(s)
Avastrovirus/genética , Genoma Viral/genética , Animales , Avastrovirus/clasificación , Avastrovirus/aislamiento & purificación , Pollos , Epítopos/genética , India , Homología de Secuencia de Ácido NucleicoRESUMEN
A study was conducted to detect and characterize the enteric viruses (chicken astrovirus, avian nephritis virus and avian orthoreovirus) present in flocks of commercial broiler chickens suffering from enteritis in Haryana, India. The intestinal contents were collected from 65 enteritis-affected flocks (cases) and tested by reverse transcription PCR (RT-PCR). Of these 65 cases, 35 (53.80%) were positive for a single virus and 26 (40.00%) for two viruses. The remaining four samples were negative for all three viruses tested. Of the 65 cases, 57 were positive for chicken astrovirus (CAstV) while 30 cases had avian nephritis virus (ANV). None of the cases were positive for orthoreovirus. Comparison of 12 CAstVs of this study with previously published CAstV sequences revealed nucleotide identities ranging from 73.20 to 98.00%. The nucleotide identities ranged between 83.10-95.50% when nine ANVs of this study were compared with previously reported ANV sequences. The amino acid sequences of CAstVs in comparison to previously published sequences revealed certain unique changes. Phylogeny based on polymerase gene revealed that CAstVs and ANVs of this study were under the same monophyletic clade. In conclusion, a large number of broiler chicken flocks experiencing enteritis were positive for CAstV and ANV by RT-PCR. The presence of more than one enteric virus in enteritis-affected flocks and changes at the genetic level in these viruses may affect the severity of disease.
Asunto(s)
Infecciones por Astroviridae/veterinaria , Avastrovirus/aislamiento & purificación , Enteritis/veterinaria , Orthoreovirus Aviar/aislamiento & purificación , Enfermedades de las Aves de Corral/virología , Infecciones por Reoviridae/veterinaria , Animales , Infecciones por Astroviridae/epidemiología , Infecciones por Astroviridae/virología , Avastrovirus/clasificación , Avastrovirus/genética , Pollos/virología , Enteritis/virología , India/epidemiología , Orthoreovirus Aviar/clasificación , Orthoreovirus Aviar/genética , Filogenia , Enfermedades de las Aves de Corral/epidemiología , Infecciones por Reoviridae/epidemiología , Infecciones por Reoviridae/virología , Pavos/virologíaRESUMEN
Avian nephritis virus (ANV), which belongs to the family Astroviridae, is associated with different clinical manifestations (including enteric disorders). Despite being frequently found in the avian industry worldwide, information regarding genetic features of these viruses in Brazil is scarce. Therefore, sixty fecal sample pools (5-6 birds of the same flock), representing 60 poultry farms from six Brazilian States, were screened using an astrovirus-specific hemi-nested-PCR assay targeting the conserved ORF1b gene, followed by nucleotide sequencing of amplified products. PCR and phylogenetic analysis confirmed the detection of 21 positive samples to ANV (35 %). In order to investigate the genetic diversity represented by these viruses, amplification, cloning and phylogenetic analysis of the deduced amino acid sequence of ORF2 gene were attempted. Eight samples were successfully cloned (generating 32 clones in total) and sequenced. Based on phylogenetic analysis of ORF2, sequences defined in this study were classified into three genotypes: genotype 5, which has already been described in birds, and two other novel genotypes, tentatively named genotype 8 and 9, all of which occurred in single or mixed infections. Moreover, high intra-genotypic diversity and co-circulation of distinct strains in a same host population were observed. This study revealed the presence of new strains of ANV in Brazilian poultry and their circulation in commercial chicken flocks.