| molecular characterization and typing of chicken and turkey astroviruses circulating in the united states: implications for diagnostics. | avian astroviruses were detected by reverse transcriptase and polymerase chain reaction in intestinal contents collected from commercial chickens and turkeys from throughout the united states from 2003 through 2005. astroviruses were detected in birds from both healthy and poorly performing flocks with or without enteric disease. phylogenetic analysis was performed with sequence data from the polymerase (orf-1b) genes of 41 turkey-origin astroviruses and 23 chicken-origin astroviruses. all curre ... | 2006 | 17039840 |
| co-circulation of distinct genetic lineages of astroviruses in turkeys and guinea fowl. | viruses belonging to the genus astrovirus have been increasingly associated with enteritis in mammalian and avian species, including turkeys. more recently, astroviruses have also been detected in diseased guinea fowl. in turkeys, two genetically distinct types of astrovirus have been reported, namely turkey astrovirus 1 and 2 (tastv1 and tastv2). the prevalence and the pathogenesis of astrovirus infections in this species is currently unknown, with the exception of data generated in the usa. in ... | 2007 | 17106624 |
| pathogenicity of turkey astroviruses in turkey embryos and poults. | the pathogenicity of turkey astrovirus 2001 (tastv2001) and turkey astrovirus 1987 (tastv1987) in specific-pathogen-free (spf) turkey embryos and commercial poults was investigated. the virus shedding in poults was monitored using electron microscopy (em) and reverse transcription-polymerase chain reaction (rt-pcr) during the 14-day experimental period. both viruses caused enteritis and growth depression in spf turkey embryos and poults. the tastv2001 did not induce macroscopic or microscopic le ... | 2006 | 17274289 |
| photocatalytic inactivation of diarrheal viruses by visible-light-catalytic titanium dioxide. | titanium dioxide (tio2) that had been irradiated with visible light (vl) was demonstrated to inactivate rotavirus, astrovirus, and feline calicivirus (fcv). the virus titers were dramatically reduced after exposure for 24 hrs to the vl-catalytic tio2. the addition of bovine serum albumin could protect the virus against inactivation by vl-catalytic tio2 in a dose-dependent manner. this finding implied that the vl-catalytic tio2 products might somehow interact initially with the viral proteins in ... | 2007 | 17821945 |
| periodic monitoring of commercial turkeys for enteric viruses indicates continuous presence of astrovirus and rotavirus on the farms. | a longitudinal survey to detect enteric viruses in intestinal contents collected from turkeys in eight commercial operations and one research facility was performed using molecular detection methods. intestinal contents were collected from turkeys prior to placement, with each flock resampled at 2, 4, 6, 8, 10, and 12 wk of age. the samples were screened for astrovirus, rotavirus, reovirus, and turkey coronavirus (tcov) by a reverse transcriptase and polymerase chain reaction (rt-pcr), and for g ... | 2007 | 17992925 |
| a multiplex rt-pcr test for the differential identification of turkey astrovirus type 1, turkey astrovirus type 2, chicken astrovirus, avian nephritis virus, and avian rotavirus. | recent studies have revealed the presence ofastroviruses and rotavirus in numerous poorly performing and healthy chicken and turkey flocks in the united states. the phylogenetic analysis of the sequence data produced during these studies has identified four groups of avian astroviruses circulating in the united states: turkey astrovirus types 1 and 2 (tastv-1 and tastv-2), avian nephritis virus (anv), and a chicken-origin astrovirus (castv). as the molecular epidemiology of poultry enteric disea ... | 2007 | 17992926 |
| genomic analysis of closely related astroviruses. | to understand astrovirus biology, it is essential to understand factors associated with its evolution. the current study reports the genomic sequences of nine novel turkey astrovirus (tastv) type 2-like clinical isolates. this represents, to our knowledge, the largest genomic-length data set available for any one astrovirus type. the comparison of these tastv sequences suggests that the tastv species contains multiple subtypes and that recombination events have occurred across the astrovirus gen ... | 2008 | 18321976 |
| pathogenesis of type 2 turkey astroviruses with variant capsid genes in 2-day-old specific pathogen free poults. | the pathogenicity of three different type 2 turkey astroviruses (tastv-2) was studied in specific pathogen free turkeys. these viruses differ based on sequence analysis of the capsid gene. poults were inoculated at 2 days of age and examined during 14 days for clinical signs and virus shedding. all inoculated poults presented signs of enteric disease including diarrhoea and growth depression. virus presence and shedding was detected by real-time reverse transcriptase-polymerase chain reaction fr ... | 2008 | 18393099 |
| detection of turkey astrovirus in young poults affected with poult enteritis complex in brazil. | reverse transcription polymerase chain reaction (rt-pcr) of turkey astrovirus (tastv) capsid and polymerase genes was applied to the bursa of fabricius (bf), thymus (th), spleen (sp) and cloacal swabs (cs) of young poults with "poult enteritis complex" (pec). the histological lesions included atrophy, lymphoid depletion, cellular infiltration and necrosis of the bf, th and sp, respectively. the rt-pcr reactions were positive for the polymerase gene of tastv-2 in all 100 css, 7 out of 10 of bfs a ... | 2008 | 18628608 |
| enteric viruses detected by molecular methods in commercial chicken and turkey flocks in the united states between 2005 and 2006. | intestinal samples collected from 43 commercial broiler and 33 commercial turkey flocks from all regions of the united states during 2005 and 2006 were examined for the presence of astrovirus, rotavirus, reovirus, and coronavirus by reverse transcription-polymerase chain reaction (pcr), and for the presence of groups 1 and 2 adenovirus by pcr. phylogenetic analysis was performed to further characterize the viruses and to evaluate species association and geographic patterns. astroviruses were ide ... | 2008 | 18646452 |
| identification of chicken enterovirus-like viruses, duck hepatitis virus type 2 and duck hepatitis virus type 3 as astroviruses. | earlier work identified and biologically characterized antigenically distinct enterovirus-like viruses (elvs) of chickens. three of these elvs can now be identified as astroviruses. characterization involved the use of a hitherto undescribed, degenerate primer-based reverse transcription-polymerase chain reaction (rt-pcr) to amplify astrovirus open reading frame (orf) 1b-specific cdna fragments followed by nucleotide sequence determination and analysis of the amplified fragments. elv-1 was confi ... | 2009 | 19156577 |
| complete sequence of a duck astrovirus associated with fatal hepatitis in ducklings. | duck astroviruses (dastvs) are known to cause duck viral hepatitis; however, little is known regarding their molecular biology. here, we report the complete sequence of a dastv associated with a recent outbreak of fatal hepatitis in ducklings in china. sequence analyses indicated that the genome of dastv possessed a typical astrovirus organization and also exhibited two unique features. the polyadenylated genome comprised 7722 nt, which is the largest among astroviruses sequenced to date. the or ... | 2009 | 19264607 |
| experimental reproduction of poult enteritis syndrome: clinical findings, growth response, and microbiology. | poult enteritis syndrome (pes) is an infectious disease of turkey poults characterized by diarrhea, dullness, and depression. five experiments were conducted to reproduce the disease in turkey poults using intestinal contents of pes-affected birds. in all experiments, poults at 14 d of age were divided into 4 groups and were orally given 2 ml of unfiltered supernatant, filtered supernatant, sediment dissolved in pbs, or pbs alone. inocula in experiments 1, 3, and 5 consisted of intestinal conten ... | 2009 | 19359682 |
| detection of chicken astrovirus by reverse transcriptase-polymerase chain reaction. | the development of a reverse transcriptase-polymerase chain reaction (rt-pcr) test for detecting chicken astroviruses (castv) is described. primers, which amplified a fragment of 510 base pairs, were located in conserved regions within the orf 1b (rna polymerase) gene. the limit of detection of the test was estimated to be approximately 60 viral copies using a 10-fold dilution series of in vitro transcribed rna. positive signals were produced with representative castv samples, some of which were ... | 2009 | 19937514 |
| a seroprevalence investigation of chicken astrovirus infections. | two genetically different isolates of chicken astrovirus (castv), named castv612 and castv11672, which share low levels of antigenic relatedness in cross-indirect immunofluorescence (iif) tests, have been identified recently. in the present study, separate iif tests for detecting antibodies to the castv612 and castv11672 isolates have been used to determine the seroprevalences of castv infections in four generations of flocks involved in broiler chicken production. castv antibodies were detected ... | 2009 | 19937515 |
| a purified recombinant baculovirus expressed capsid protein of a new astrovirus provides partial protection to runting-stunting syndrome in chickens. | a new viral sequence likely belonging to a virus of the family astroviridae was determined using the gut content of chickens affected with the runting-stunting syndrome (rss) in chickens. since the appropriate virus could not be isolated in cell culture the open reading frame of the viral capsid protein was cloned to generate a recombinant baculovirus. the protein was purified and used as an experimental vaccine in broiler breeders to provide maternal derived antibodies for the protection of the ... | 2010 | 19941993 |
| detection and molecular characterization of enteric viruses from poult enteritis syndrome in turkeys. | this study was conducted to detect and characterize enteric viruses [rotavirus, turkey astrovirus-2 (tastv-2), reovirus, and turkey coronavirus] from cases of poult enteritis syndrome (pes) in minnesota turkeys. of the intestinal contents collected from 43 pes cases, 25 were positive for rotavirus and 13 for small round viruses by electron microscopy (em). of the enteric virus-positive cases by em (n=27), 16 cases had rotavirus or small round viruses alone and the remaining 11 cases had both vir ... | 2010 | 20075272 |
| duration of growth depression and pathogen shedding in experimentally reproduced poult enteritis syndrome. | an experimental study was conducted to determine the duration of growth depression and virus shedding in turkey poults after oral inoculation with intestinal contents from birds affected with poult enteritis syndrome (pes). poults at day 14 of age were divided into four groups (groups a, b, c, and d) of 40 poults each and inoculated orally with unfiltered supernatant, filtered supernatant, sediment suspended in phosphate-buffered saline (pbs), or pbs alone (control), respectively. the poults wer ... | 2009 | 20095151 |
| astrovirus infection induces sodium malabsorption and redistributes sodium hydrogen exchanger expression. | astroviruses are known to be a leading cause of diarrhea in infants and the immunocompromised; however, our understanding of this endemic pathogen is limited. histological analyses of astrovirus pathogenesis demonstrate clinical disease is not associated with changes to intestinal architecture, inflammation, or cell death. recent studies in vitro have suggested that astroviruses induce actin rearrangement leading to loss of barrier function. the current study used the type-2 turkey astrovirus (t ... | 2010 | 20219227 |
| detection and molecular characterization of enteric viruses in breeder turkeys. | the present study was undertaken to detect and characterize enteric viruses (rotavirus, astrovirus, reovirus, and coronavirus) in breeder poults. five turkey breeder flocks were selected. faecal samples were collected from all flocks at 1 week of age and then every other week until the poults reached 9 weeks of age. the faecal samples were pooled in groups of five. of the 193 pools ("samples") tested by reverse transcription-polymerase chain reaction, 47.2%, 30.6%, and 10.4% samples were positiv ... | 2010 | 20390537 |
| astrovirus, reovirus, and rotavirus concomitant infection causes decreased weight gain in broad-breasted white poults. | turkey astrovirus type-2 (tastv-2), turkey rotavirus (trotv), and turkey reovirus (treov) have been implicated as possible causes of enteric diseases and poor production in turkeys; however, numerous studies with each individual virus have failed to reproduce the disease as observed in the field. therefore, in this study we evaluated the pathogenesis of all possible combinations of one, two, or three viruses in comparison to sham inoculates in 3-day-old turkey poults. body weights were recorded ... | 2010 | 20408393 |
| development and application of an rt-pcr test for detecting avian nephritis virus. | the development of a reverse transcriptase-polymerase chain reaction (rt-pcr) test for detecting avian nephritis virus (anv) is described. primers, which amplified a fragment of 182 base pairs (bp), were located in the conserved 3' untranslated region (utr) of the genome. the limit of detection of the test was estimated to be approximately 18 viral copies using a 10-fold dilution series of in vitro transcribed rna. positive signals were produced with representative anv samples, some of which wer ... | 2010 | 20544427 |
| identification of a novel astrovirus in a domestic pig in hungary. | the family astroviridae consists of two genera, avastrovirus and mamastrovirus, whose members are associated with gastroenteritis in avian and mammalian hosts, respectively. we serendipitously identified a novel porcine astrovirus in a fecal specimen from a domestic pig (sus scrofa domestica) in hungary. sequencing of a fragment indicated that it was an orf1b/orf2/3'utr sequence, and it has been submitted to the database as porcine astrovirus type 2 (pastv-2/hungary/2007) with accession number g ... | 2010 | 20931250 |
| detection of avian nephritis virus in australian chicken flocks. | avian nephritis virus (anv) is thought to infect poultry flocks worldwide, but no confirmed case has been reported in australia. the first such case is described in this study. cases of young chickens with clinical signs of dehydration and diarrhea were submitted to our laboratory and histopathology detected interstitial nephritis. vaccine strains of infectious bronchitis virus were detected in some of these cases but were not considered to be the causative agent. a total of seven fresh submissi ... | 2010 | 20945778 |
| molecular characterization of avian astroviruses. | astroviruses are frequently associated with enteric diseases in poultry, being isolated from cases of runting-stunting syndrome (rss) of broiler chickens, poult enteritis complex (pec), and poult enteritis mortality syndrome (pems) of turkeys. currently, five types of avian astrovirus have been identified: turkey astroviruses 1 and 2 (tastv-1, tastv-2), avian nephritis virus (anv), chicken astrovirus (castv) and duck astrovirus (dastv). the objective of this study was to molecularly characterize ... | 2010 | 21069394 |
| development and evaluation of real-time taqman® rt-pcr assays for the detection of avian nephritis virus and chicken astrovirus in chickens. | the development and preliminary evaluations of two taqman®-based, real-time reverse transcriptase-polymerase chain reaction (rrt-pcr) assays for the quantitative detection of avian nephritis virus (anv) and chicken astrovirus (castv) rnas are described. the assays used amplicons generated from the 3' untranslated region of the anv genome and a conserved region of castv open reading frame 1b including its junction with open reading frame 2. high virus rna levels (>10(5.99) viral copies) were dete ... | 2010 | 21154056 |
| comparison of capsid gene sequences of turkey astrovirus-2 from poult-enteritis-syndrome-affected and apparently healthy turkeys. | this study was conducted to determine genetic variations in the capsid gene of turkey astrovirus-2 (tastv-2) detected in apparently healthy and poult enteritis syndrome (pes)-affected turkeys. capsid genes of astroviruses obtained from 30 pes-affected and 45 apparently healthy turkey flocks had sequence homologies of 73.4-100% and 72.4-100% at the nucleotide levels, respectively. the analysis of deduced amino acid sequences revealed one amino acid deletion at position 552 in 28 (93.3%) of 30 pes ... | 2011 | 21327787 |
| one-year molecular survey of astrovirus infection in turkeys in poland. | the presence of turkey astrovirus (tastv) was monitored in meat-type turkey flocks in poland in 2008. clinical samples (10 individual faecal swabs/flock) from 77 flocks aged 1-19 weeks were collected from different regions of the country. rt-pcr experiments were performed for detection and molecular characterization of tastv using four sets of primers within the rdrp gene (orf1b). the prevalence of astrovirus was 34/77 (44.15%) in the flocks tested. tastv type 2 was associated with 30 of 77 infe ... | 2011 | 21404112 |
| detection and characterization of avian nephritis virus in ducklings. | the first evidence of avian nephritis virus (anv) in ducks is described. a diagnostic investigation was performed on three duck farms in croatia. samples from dead-in-shell ducklings and ducklings aged 30 days were collected and prepared for molecular and histopathological examination. intestinal and liver samples were tested by polymerase chain reaction (pcr) for the presence of anv, duck enteritis virus, duck hepatitis virus 1 and derzsy's disease virus. multiple tissues were collected for his ... | 2011 | 21500037 |
| sequence analyses of the representative chinese-prevalent strain of avian nephritis virus in healthy chicken flocks. | avian nephritis virus (anv), which belongs to the astroviridae family, has been associated with acute nephritis in chickens. cases of anv infection have been recorded in japan and in several european countries. however, related studies have never been performed in china. thus, this study isolated anv in chinese chicken flocks. anv rna was detected by reverse transcription-pcr in stool samples collected from healthy layer chickens in the sichuan province of china in 2009. of the 192 stool specime ... | 2011 | 21500638 |
| complete sequence and genetic characterization of pigeon avian nephritis virus, a member of the family astroviridae. | in the current study, the complete genome sequence of a member of the family astroviridae isolated from pigeons was determined through genetic characterization and phylogeny analysis. the isolated genome sequence was proposed to be that of pigeon avian nephritis virus (anv), whose genome structure and characteristics were similar to previously reported avian astroviruses. the sequenced ssrna genome comprises 6928 nucleotides, excluding the poly(a) tail, and contains three open reading frames. ph ... | 2011 | 21618030 |
| detection of astrovirus infection in pigeons (columbia livia) during an outbreak of diarrhoea. | avian astrovirus infections are widespread in many countries, and infections have been linked to enteritis and increased mortality in young poultry. although pigeons are treated as an important poultry product in some countries, their diseases are often poorly understood and astrovirus infection in pigeons has not been reported. in the present study, faecal samples were collected during an outbreak of gastrointestinal illness in a population of shanghai pigeons. the samples were examined for ast ... | 2011 | 21812714 |
| detection and characterization of a new astrovirus in chicken and turkeys with enteric and locomotion disorders. | in the present paper, we report the unexpected discovery of a new virus in samples from chicken and turkey flocks with clinical disorders such as tenosynovitis, enteric problems, or runting and/or stunting-like conditions. since 1987, several virus isolation attempts on samples from these flocks resulted in the same macroscopic characteristic lesions in embryonated specific pathogen free eggs, being mortality with bright-red discolouration of legs and wing-tips, a swollen dark-red liver and oede ... | 2011 | 21780967 |
| crystal structure of the human astrovirus capsid spike. | astroviruses are single-stranded, plus-sense rna viruses that infect both mammals and birds, causing gastroenteritis and other extraintestinal diseases. clinical studies have established astroviruses as the second leading cause of viral diarrhea in young children. here we report the crystal structure of the human astrovirus dimeric surface spike determined to 1.8-å resolution. the overall structure of each spike/projection domain has a unique three-layered ß-sandwiches fold, with a core, six-str ... | 2011 | 21768348 |
| the role of type-2 turkey astrovirus in poult enteritis syndrome. | an experimental study was conducted to determine the comparative pathogenicity of type-2 turkey astrovirus (tastv-2) obtained from turkey flocks afflicted with poult enteritis syndrome (pes) and from turkey flocks displaying no apparent signs of infection. in total, ninety 7-d-old poults, which tested negative for the presence of astrovirus, rotavirus, coronavirus, and reovirus by reverse transcriptase (rt) pcr , were divided evenly into 3 groups: a, b, and c. birds in group a were inoculated or ... | 2011 | 22080013 |
| screening of feral and wood pigeons for viruses harbouring a conserved mobile viral element: characterization of novel astroviruses and picornaviruses. | a highly conserved rna-motif of yet unknown function, called stem-loop-2-like motif (s2m), has been identified in the 3' end of the genomes of viruses belonging to different rna virus families which infect a broad range of mammal and bird species, including astroviridae, picornaviridae, coronaviridae and caliciviridae. since s2m is such an extremely conserved motif, it is an ideal target for screening for viruses harbouring it. in this study, we have detected and characterized novel viruses harb ... | 2011 | 22043297 |
| identification of a novel astrovirus in domestic sheep in hungary. | the family astroviridae consists of two genera, avastrovirus and mamastrovirus, whose members are associated with gastroenteritis in avian and mammalian hosts, respectively. we serendipitously identified a novel ovine astrovirus in a fecal specimen from a domestic sheep (ovis aries) in hungary by viral metagenomic analysis. sequencing of the fragment indicated that it was an orf1b/orf2/3'utr sequence, and it has been submitted to the genbank database as ovine astrovirus type 2 (oastv-2/hungary/2 ... | 2011 | 22033597 |