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At least 19 recordsLinked to original sources

Genomic characterisation of the large segment of a rabbit picobirnavirus and comparison with the atypical picobirnavirus of Cryptosporidium parvum.

The 2362 base pair sequence of the larger of the two double stranded RNA genome segments of a rabbit strain of picobirnavirus (PBV) has a major open reading frame (ORF) of 591 amino acids and two smaller ORFs of 55 and 155 amino acids. A clone of the segment did not hybridise with other viral bisegmented ds RNAs from faecal samples. There is no relationship in sequence or organisation between this PBV sequence and the bisegmented dsRNAs found associated with Cryptosporidium parvum. This suggests that there are at least two distinct classes of bisegmented dsRNA viruses or viral-like agents in faeces.

Animals↗

Detection and characterization of a novel bisegmented double-stranded RNA virus (picobirnavirus) from rabbit faeces.

In two separate studies rabbits were fed orally with human and rabbit "picobirnaviruses". Polyacrylamide gel electrophoresis (PAGE) of nucleic acid extracted from faecal samples collected from inoculated rabbits revealed the presence of discrete equimolar bands, typical of picobirnaviruses, in several specimens. The genome profiles detected in both studies differed significantly from that of the inoculum suggesting that passage of the inoculated picobirnaviruses had not taken place and that the bands were a co-incidental finding. The presence of rabbit picobirnaviruses was confirmed by characterization of the genome bands, as dsRNA by enzyme digestion and by their co-sedimentation in caesium chloride (CsCl) gradients with 32 nm virus particles at a buoyant density of 1.39 g/ml. Picobirnavirus genome segments varied in size in a range between 2.3-2.6 kilo base pairs (kbp) and 1.6-1.9 kbp for the slow and fast migrating bands, respectively. Immune electron microscopy of the picobirnavirus particles revealed round or slightly hexagonal particles with a smooth surface and a mean diameter of 30.7 nm. In one rabbit, an immune response, temporally associated with picobirnaviruses excretion, was demonstrated by immune electron microscopy (IEM) supporting the view that picobirnaviruses may be vertebrate viruses. Two antigenically distinct picobirnavirus strains were defined by IEM.

Animals↗

Detection of picobirnavirus in HIV-infected patients with diarrhea in Argentina.

Diarrhea due to enteric pathogens is an important complication of advanced HIV infection. Picobirnaviruses are agents recently linked with human enteritis. In total, 197 fecal samples collected from HIV-infected and noninfected patients with and without diarrhea were investigated for the presence of rotavirus and picobirnavirus by polyacrylamide gel electrophoresis. Picobirnavirus was detected in 8.8% of 57 HIV-infected patients with diarrhea, but it was detected in neither those without diarrhea (p<.018) nor in the group of subjects uninfected with HIV (p<.022). All genomic electropherotypes of picobirnavirus strains had a wide pattern. Picobirnavirus genome segments varied in size between 2.4 and 2.7 and 1.6 and 1.9 kbp for the slow and fast migrating bands, respectively. Rotaviruses were not detected in any of the clinical groups studied. Two methods for the extraction of nucleic acid-phenol/chloroform and guanidinium thiocynate (GTC)/silica-were compared. Detection of picobirnavirus by polyacrylamide gel electrophoresis was 2.5 times more sensitive following guanidinium thiocynate RNA extraction. This investigation offers preliminary results about the circulation of picobirnavirus in HIV-infected patients in Córdoba, Argentina.

Adult↗

Cloning of human picobirnavirus genomic segments and development of an RT-PCR detection assay.

Nearly full-length genomic segments 2 and a partial-length genomic segment 1 of human picobirnavirus were cloned and sequenced. The clones were derived from viruses obtained from human immunodeficiency virus (HIV)-infected patients in Atlanta, Georgia (strains 3-GA-91 and 4-GA-91) and a nonHIV-infected person from China (strain 1-CHN-97). The picobirnavirus genomic segments lacked sequence similarities with other viral sequences in GenBank and EMBL. Comparison of genomic segment 1 from a human and a rabbit picobirnavirus identified a region of 127 nucleotides with 54.7% identity. The genomic segments 2 of the 4-GA-91 and 1-CHN-97 strains had 41.4% nucleic acid identity and 30.0% amino acid similarity and contained amino acid motifs typical of RNA-dependent RNA polymerase genes. Reverse transcription-PCR detection assays were developed with primers targeted to the genomic segments 2 of strains 4-GA-91 or 1-CHN-97. Picobirnaviruses related to the China strain were the predominant viruses detected in stool samples from people in four countries on three continents. Picobirnaviruses were detected in samples from two outbreaks of gastroenteritis in long-term elder care facilities but were not determined to be the primary pathogen. Our findings support the view that picobirnaviruses constitute a distinct family of viruses.

Amino Acid Sequence↗

Identification of picobirnavirus from faeces of Italian children suffering from acute diarrhea.

Polyacrylamide gel electrophoresis of nucleic acid extracted from stool samples of diarrhoeic children revealed in 3 out of 690 (0.43%) specimens two electrophoretic bands with a migration pattern characteristic of picobirnavirus ds-RNA. In none of the 92 control children were similar bands detected. No other potential enteric pathogens were found in the patients with picobirnavirus infection.

Child↗

Detection of a picobirnavirus associated with Cryptosporidium positive stools from humans.

A picobirnavirus with an atypical genome profile was detected by polyacrylamide gel electrophoresis (PAGE) in 37% (20/54) of human faecal samples also containing oocysts of Cryptosporidium typical of C. parvum. This virus shares many of the characteristics of the previously described picobirnaviruses, but has a significantly smaller genome (1.75 and 1.55 Kbp).

Animals↗

Identification of picobirnavirus, viruses with bisegmented double stranded RNA, in rabbit faeces.

Picobirnaviruses are a novel group of viruses recently found in the faeces of several species of vertebrates. Examination by polyacrylamide gel electrophoresis of rabbit faecal samples collected in one animal facility revealed the viruses in 23 (11 per cent) of 211 samples. Further analysis by electron microscopy and caesium chloride isopycnic centrifugation confirmed the presence of picobirnaviruses in the samples. The oral inoculation of three newly weaned rabbits with purified viruses resulted in the excretion of a virus with an electropherotype similar to the inoculum, by two of the three inoculated animals. Maximal viral shedding was detected 13 days after inoculation. No sign of diarrhoea was observed either in the inoculated animals or in the virus excreting animals surveyed. No antibody activity could be detected in the paired serum samples taken from the inoculated animals.

Animals↗

Picobirnavirus, a novel group of undescribed viruses of mammals and birds: a minireview.

Picobirnavirus, a novel group of viruses recently detected in children and several species of animals including chickens, are different from the existing members of the family Birnaviridae. Picobirnavirus (PBV) is the tentatively proposed name for the group of these viruses. These viruses are 30-40 nm in diameter and have icosahedral symmetry with triangulation number (T) equal to 3. Their buoyant density in CsCl is 1.4 g/ml. Their genome is bi- or trisegmented double-stranded RNA (dsRNA) with segment lengths of 2.6 and 1.9 kbp for bisegmented and 2.9, 2.4 and 0.9 kbp for trisegmented genomes. The electrophoretic migration profile has considerable heterogeneity. PVBs are detected in diarrhoeic as well as non-diarrhoeic animals, hence, their potential needs further investigation.

Animals↗

Detection and characterisation of bisegmented double-stranded RNA viruses (picobirnaviruses) in human faecal specimens.

The prevalence of picobirnaviruses (PBVs) in human stools was investigated by polyacrylamide gel electrophoresis (PAGE) analysis of 832 faecal specimens collected between 1982 and 1993 from patients in various clinical groups. Similar prevalences (9-13%) were detected in patients with or without gastroenteritis and throughout the age range of 3 to > 65 years. Two methods for the extraction of nucleic acid, a phenol/chloroform method and a guanidinium thiocynate (GTC)/silica method, were compared. Detection of PBVs by PAGE was three times more sensitive following RNA extraction by the GTC/silica method. Characterisation of three strains was carried out. Segment sizes ranged from 1.625 to 1.95 kilo base pairs (Kbp) and 2.2 to 2.5 Kbp for the fast and slow migrating bands, respectively. The nuclic acid was shown to be double-stranded RNA (dsRNA) by nuclease digestion. PBV-like particles were detected by electron microscopy in two PAGE-positive stools. Virion diameters ranged from 35 to 41 nm and a buoyant density of 1.38-1.4 g/ml in caesium chloride (CsCl) was demonstrated. These findings suggest that PBVs are widespread in humans in the United Kingdom. However, no disease association could be demonstrated.

Adolescent↗

Identification of a bisegmented double-stranded RNA virus (picobirnavirus) in calf faeces.

To determine the incidence of rotavirus infection among dairy herds in the State of São Paulo, Brazil, 576 faecal samples obtained from calves aged 1-45 days with and without diarrhoea, reared on 63 dairy cattle farms, were analyzed. Polyacrylamide gel electrophoresis (PAGE) identified 28 samples positive for group A rotavirus, while four samples, two diarrhoeic and two non-diarrhoeic, showed a bisegmented genome with a typical picobirnavirus pattern. Electron microscopy revealed spherical virus particles with a diameter of 37 nm and without a defined surface structure. The present study is the first report of a bisegmented virus identified in cattle in Brazil.

Animals↗

Molecular diversity of partial-length genomic segment 2 of human picobirnavirus.

OBJECTIVES: This study was carried out in order to evaluate the efficacy of the recently developed picobirnavirus (PBV) sets of primers and to establish the phylogenetic relationships of Argentine strains with PBV strains isolated in China and the USA. METHODS: Thirteen fecal specimens tested as positive for PBV by polyacrylamide gel electrophoresis were analyzed by reverse transcription-polymerase chain reaction assays using primers target to the genomic segments 2 of PBV strains isolated in China and the USA. The amplicons were sequenced and analyzed. RESULTS: Primers derived from the China strain produced amplicons in only 4 of the 13 specimens (30.76%). No sample was revealed as positive with the primers derived from the US strain. DNA sequencing of polymerase chain reaction products differed in nucleic acid and amino acid sequences by 13.9-42.28% and 18.1-51.1%, respectively. Despite this strain diversity, three domains of conserved nucleotide sequences as well as the amino acid motif D-S-D typical of RNA-dependent RNA polymerase gene of double-strand RNA viruses were identified. Comparatively, these conserved regions were also identified in homologous PBV strains from the USA and China. Phylogenetic analysis showed no time or geographic clustering. CONCLUSIONS: These findings provide evidence that PBV may represent an emerging heterogeneous group of viruses.

Adolescent↗

Enteric viruses and diarrhea in HIV-infected patients. Enteric Opportunistic Infections Working Group.

BACKGROUND: Diarrhea occurs frequently among persons with the acquired immunodeficiency syndrome, but the cause often remains unknown. We used a group of diagnostic assays to determine which viruses were etiologic agents of diarrhea in a group of persons infected with the human immunodeficiency virus (HIV). METHODS: Stool and serum specimens were obtained from HIV-infected patients enrolled in a longitudinal study in Atlanta. Fecal specimens from patients with diarrhea and from control patients without diarrhea were screened by electron microscopy, polyacrylamide-gel electrophoresis, and enzyme immunoassays for rotaviruses, enteric adenoviruses, caliciviruses, picobirnaviruses, and astroviruses. Paired serum samples were tested for antibody responses to Norwalk virus and picobirnavirus. RESULTS: Viruses were detected in 35 percent of 109 fecal specimens from patients with diarrhea but in only 12 percent of 113 specimens from those without diarrhea (P < 0.001). Specimens from patients with diarrhea were more likely than those from patients without diarrhea to have astrovirus (12 percent vs. 2 percent, P = 0.003); picobirnavirus (9 percent vs. 2 percent, P = 0.017); caliciviruses, including small round structured viruses (6 percent vs. 1 percent, P = 0.062); and adenoviruses (9 percent vs. 3 percent, P = 0.047). They were also more likely to have a mixed viral infection (6 percent vs. 0 percent, P = 0.006). With the use of polyacrylamide-gel electrophoresis to analyze concentrated RNA extracts from stool, picobirnavirus was detected in fecal specimens from 6 of the 65 patients with diarrhea and was associated with prolonged viral shedding and chronic diarrhea. No rotaviruses, enteric adenoviruses, or instances of seroconversion to positivity for Norwalk virus were observed. CONCLUSIONS: Novel enteric viruses such as astrovirus and picobirnavirus may be more important etiologic agents of diarrhea in HIV-infected patients than previously recognized and may be more common than either bacterial or parasitic enteropathogens.

Adenoviruses, Human↗

Diarrhea and enteric emerging viruses in HIV-infected patients.

To evaluate the prevalence of enteric viruses and their possible association with diarrhea, 244 stool samples were collected from HIV-infected and uninfected patients with or without diarrhea (subgroups I-a, Ib, II-a, and II-b, respectively). Subjects were screened by polyacrylamide gel electrophoresis, latex agglutination, and enzyme immunoassays for rotaviruses, adenoviruses, picobirnaviruses, and astroviruses. Enteric viruses were found significantly more often in specimens from HIV patients (20%) than in specimens from uninfected HIV patients (0%) (p < 0.05). Picobirnavirus was detected in 14.63% of 82 HIV-infected patients with diarrhea, but it was detected neither in those without diarrhea (0%) (p < 0.05) nor in the groups of uninfected HIV subjects (0%) (p < 0.05). Nor could astrovirus (subgroups I-a [4.00%] versus subgroup I-b [5.26%],p > 0.05) or enteric adenovirus (subgroup I-a [1.22%] versus subgroup I-b [0%], p > 0.05) be linked to the diarrhea disorder in HIV-infected patients. Rotaviruses were not detected in any of the clinical subgroups studied. Enteric viruses were detected in 15 of 93 (16.13%) of the HIV-infected patients with CD4+ T cell count <200/microl and 3 of 19 (15.79%) of those HIV-infected individuals with a CD4+ T cell count 200-499/microl, showing no significant difference (p > 0.05). According to our data, unusual enteric viruses such as picobirnavirus, astrovirus, and enteric adenovirus occur in HIV-infected population in Córdoba, Argentina. However, only picobirnaviruses could be significantly associated with diarrhea in these patients.

Argentina↗

Prevalence of enteric viruses in human immunodeficiency virus seropositive patients in Venezuela.

The prevalence of enteric viruses associated with gastroenteritis was determined in 125 stool samples from patients infected with the human immunodeficiency virus (HIV), with or without diarrhea. Diagnostic assays included enzyme immunoassays for the identification of rotavirus, adenovirus, and Norwalk virus; polyacrylamide gel electrophoresis for atypical rotaviruses and picobirnaviruses and polymerase chain reaction for astrovirus. Enteric viruses were detected in 6.4% (8 of 125) of the stools collected: five (4.0%) samples positive for adenoviruses, and three (2.3%) samples positive for picobirnaviruses were detected. No rotavirus, astrovirus, or Norwalk virus were observed. Only one of the viruses identified (adenovirus) was found in a sample from a patient with diarrhea. Viruses were detected in 10% of the patients with AIDS, 14% of the symptomatic patients, and none of the asymptomatic persons. These results do not support a major role for enteric viruses in the diarrhea suffered by HIV-infected patients.

Acquired Immunodeficiency Syndrome↗

[Emergent riboviruses implicated in gastroenteritis].

Viral agents are one of the main causes of acute diarrhea, particularly in infants and young children. Astrovirus, coronavirus, torovirus, and picobirnavirus are increasingly being identified as causative agents of gastroenteritis. Astroviruses have been detected in the stools of between 1.2% and 20% of children with diarrhea requiring medical care in a variety of geographical areas. Outbreaks have been described in schools, day care settings and pediatric wards. Children younger than 3 years old are the most frequently affected. In temperate climates incidence is greater in winter whereas in tropical areas infection occurs throughout the year. Transmission is mainly through the fecaloral route. At least seven serotypes of human astroviruses have been recognized and serotype 1 is more common than the other serotypes. Astroviruses are often shed in stools during long periods and can be detected by electron microscopy. An enzymeimmunoassay technique that detects the astrovirus group antigen has been widely used in epidemiological studies. Nucleic acid hybridization and polymerase chain reactionbased techniques have also been used. Enteric coronaviruses have most frequently been associated with gastrointestinal disease in neonates and children younger than 12 years old. The role of toroviruses and picobirnaviruses as causative agents of gastroenteritis is still emerging. Further epidemiological studies to determine the frequency of these viruses in the community and to identify their mechanisms of transmission are needed, as are further studies to elucidate the pathophysiology of diseases due to these agents.

Acute Disease↗

Enteric virus infections and diarrhea in healthy and human immunodeficiency virus-infected children.

Forty-three stool samples from 27 human immunodeficiency virus (HIV)-seropositive children and 38 samples from 38 HIV-negative children, collected during a 15-month period, were examined for enteric viruses. Diagnostic assays included enzyme immunoassays for rotavirus, adenovirus, and Norwalk virus; polyacrylamide gel electrophoresis for picobirnavirus and atypical rotavirus; and PCR for astrovirus and enterovirus. Specimens from HIV-positive children were more likely than those of HIV-negative children to have enterovirus (56 versus 21%; P < 0.0002) and astrovirus (12 versus 0%; P < 0.02), but not rotavirus (5 versus 8%; P > 0.5). No adenoviruses, picobirnaviruses, or Norwalk viruses were found. The rates of virus-associated diarrhea were similar among HIV-positive and HIV-negative children. Enteroviruses were excreted for up to 6 months in HIV-positive children; however, no evidence for prolonged excretion of poliovirus vaccine was observed. These results suggest that although infection with enterovirus and astrovirus may be frequent in HIV-infected children, enteric viruses are not associated with the diarrhea frequently suffered by these children.

Adenovirus Infections, Human↗