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PubMedDate not supplied

Genetic characterization of poliovirus isolates in Canada, 1962-1981.

From 1962 to 1981, 629 poliovirus strains of human and sewage origin were assayed for genetic markers in the kinetic serum neutralization ( KSN ) and temperature marker (rct) tests. The KSN test proved to be most dependable: 97% of strains tested could be classified as either vaccine-like (VL) or non-vaccine-like ( NVL ). All but two of the 18 virus strains whose classification was inconclusive in the KSN test were further characterized by micro serum neutralization assay. The correlation between the results of the rct and KSN marker tests was not satisfactory for the characterization of poliovirus types 1 and 3. Numerous type 1 virus strains were analyzed with strain-specific monoclonal antibodies for antigenic markers and were examined in polyacrylamide gel electrophoreses for viral proteins. Whereas greater than 90% of poliovirus types 2 and 3 were found to be VL in the KSN test, 40% of type 1 isolates were classified as NVL . The latter were detected not only in the epidemics of 1962 and 1978-1979 caused by type 1 poliovirus but also were present in endemic form in the late 1960s and 1970s in various provinces. In contrast, no NVL type 2 strains were detected in any specimen, and the last type 3 NVL strains were demonstrated in 1963-1964. Thus only type 1 poliovirus appears to be endemic in Canada.

Adolescent↗
PubMed1996

[Subgroups classification of strains of the respiratory syncytial virus isolated in an outbreak in Ciudad de La Havana].

A high number of acute respiratory diseases was detected among children under one year admitted in a hospital of Havana City. 25 respiratory syncytial virus strains were obtained from 93 patients studied. Viral isolations were multiplied in HEP-2 cells and after observing a cytopathic effect of 80%, they were classified into subgroups by the indirect immunofluorescence technique, using anti-protein G antibodies from the respiratory syncytial virus. All the samples studied were classified within subgroup A. It is the first time a study like this is conducted in our country, which allowed us to deepen into the viral cause of these diseases and to know that the subgroup A of the respiratory syncytial virus circulated during the outbreak.

Cuba↗
PubMed1994

Nucleotide sequence of the 3' terminal region of the RNA of two filamentous grapevine viruses.

The 3' terminal region of grapevine virus A (GVA) and grapevine virus B (GVB), encompassing 1883 and 2136 nucleotides, respectively, was sequenced by the deoxynucleotide chain termination method. Three putative open reading frames (ORF) were identified in both genomic viral RNAs, denoted 1 to 3 in the 5' to 3' direction. ORF 1 encoded a polypeptide with estimated M(r) of 31 kDa (GVA) and 36.5 kDa (GVB), possessing the G/D motif of the "30 K superfamily" movement proteins, and showing good alignments with putative movement proteins of trichoviruses and capilloviruses. ORF 2 was identified as the coat protein (CP) cistron, coding for polypeptides with an estimated M(r) of 21.5 kDa (GVA) and 21.6 kDa (GVB). These CPs showed substantial sequence homology with one another and with CPs of tricho- and capilloviruses, but not of closteroviruses. ORF 3 potentially coded for two small polypeptides with estimated M(r) of 10 kDa (GVA) and 14 kDa (GVB). The ORF 3 product of GVB (14 K), but not that of GVA, shared some homology with the 3' terminal polypeptides of different plant viruses that exhibit the "zinc finger domain" of proteins with nucleic acid-binding properties. GVA and GVB have many properties in common with trichoviruses but possess an extra open reading frame (ORF 3). Whether this finding may have a bearing on the classification of these viruses is unclear. However, until the taxonomic significance of this difference in genome structure is established, it seems plausible to include GVA and GVB as tentative species in the Trichovirus genus.

Amino Acid Sequence↗
PubMed1999

[Growing divergence inside primate T cell lymphotropic viruses].

During our studies on the evolution of the PTLVs, we have isolated and genomically characterized two divergent simian T-lymphotropic viruses, not belonging to the previously well-established PTLV lineages. STLV-PH969 has been isolated from an Eritrean sacred baboon (Papio hamadryas), with an HTLV-like indeterminate serological profile. The entire 8916 nt long genomic sequence, was obtained from a cDNA library of PH969 mRNA, in combination with a PCR based strategy. All open reading frames (ORF) common to all HTLV related viruses could be identified without important deletions or insertions. Sequence comparison of the STLV-PH969 genomic sequence with the HTLV-I and -II prototype sequences revealed that this virus is equidistantly related to HTLV-I and -II. A phylogenetic analysis on the envelope and regulatory Tax proteins conclusively proved the ancient separation of HTLV-I, -II and STLV-PH969. Together these data provided enough evidence to justify the classification of this virus as a new type of primate T-lymphotropic virus, designated PTLV-L. We isolated a second highly divergent virus from pygmy chimpanzees (bonobo's, Pan paniscus) housed in the Antwerp Zoo. The animals infected with this virus showed an aberrant HTLV-I like serological profile. The entire 8855 nt long genomic sequence of the STLV-PP1664 provirus was obtained by sequencing of overlapping PCR fragments. On this sequence, all ORFs common to all HTLV related viruses could be identified without any important deletions or insertions. Sequence comparison showed that the STLV-PP1664 proviral sequence was related to HTLV-II and the virus is called STLV-II. However, in all genomic regions, STLV-IIPP1664 was much more divergent from any of the HTLV-II subtypes than these are from each other. In order to further investigate the genomic relationship of STLV-LPH969 and STLV-IIPP1664 with HTLV-I and -II, we also analyzed the genomic organization of the pX region, which differs between HTLV-I and HTLV-II. In the STLV-LPH969 and STLV-IIPP1664 producing cell lines, 2 and 5 viral messengers could be detected respectively, potentially expressing 3 and 5 different accessory proteins respectively. The splicing pattern and the resulting proteins differ from those of HTLV-I and HTLV-II. In the light of the growing interest for xenotransplantation, the prevalence of distinct PTLVs in the wild and their capacity to cross the species barrier deserves further attention.

Animals↗
PubMed1982

Structural analysis of electrophoretic variation in the genome profiles of rotavirus field isolates.

Detailed structural studies were undertaken on five isolates of bovine rotavirus which showed variability in the migration patterns of their genome segments on electrophoresis in polyacrylamide gels. The individual genome segments of each isolate were characterized by partial digestion of terminally radiolabeled RNA with a base-specific nuclease. This analysis showed that whereas mobility variations were always associated with detectable changes in nucleotide sequence, sequence changes at least as great as those found in segments showing electrophoretic mobility variations were also detected in segments showing no mobility variation. Evidence for the occurrence of genome segment reassortment between viruses in the field was obtained from analyzing the species 11 RNAs from these five isolates. The overall conclusion from these results is that great care is required in the interpretation of simple genome profile analysis of different isolates for epidemiological purposes and that classification of these viruses solely on the basis of genome electropherotype could be misleading.

Animals↗
PubMed1995

Detection and subtyping of foot-and-mouth disease virus in infected cattle by polymerase chain reaction and amplified VP1 sequencing.

Fast and accurate detection of foot-and-mouth disease (FMD) outbreaks is needed to limit spread of the disease by proper vaccination. The use of the polymerase chain reaction (PCR) has revolutionized the way in which viral diseases are diagnosed. Sequence analysis of the amplified VP1 sequence can enable the classification of FMD virus detected in the morbid animal. PCR assays were carried out to identify the virus and its serotype in suspect animals from 2 outbreaks of FMD type O virus. Sequence analysis of the amplified VP1 cDNA showed 78% homology with O1K and over 95% homology between the samples. These findings suggest that the 2 outbreaks were due to infection with the same virus serosubtype.

Amino Acid Sequence↗
PubMed1983

Characterization of Leanyer virus: resemblance to Bunyavirus.

The properties of Leanyer virus, isolated in Northern Australia in 1974, were compared with those of Bunyamwera virus. Leanyer virus replicated in BHK-21 and Vero cells. In sucrose gradients it had a density of 1.17 g/cm3 and sedimented with the same s value as Bunyamwera virus. The diameter of negatively stained virions was approximately 110 nm. Three species of RNA sedimenting at 30S (L), 26S (M) and 14S (S) and four virion proteins (L, G1, G2, N) were detected in preparations of purified virions. The results were consistent with the classification of Leanyer virus as a member of the family Bunyaviridae, possibly within the Bunyavirus genus.

Animals↗
PubMed1982

Canine parvovirus: a biochemical and ultrastructural characterization.

A canine virus derived from a diseased dog has been plaque-purified and characterized in detail. Analysis of infected cells demonstrated that virus antigen accumulated in the nucleus at 12 to 24 h post-infection and the cytopathology at the ultrastructural level was diagnostic of a parvovirus infection. The purified virus particles were 23 to 26 nm in diam. and banded at a density 1.44 g/ml in CsCl. Detailed biochemical analysis revealed a single-stranded DNA genome and three structural proteins of mol. wt. 82,300, 67,300 and 63,500. All of the data presented are consistent with the classification of this virus as a parvovirus.

Animals↗
PubMed1977

Comparisons of Venezuelan encephalitis virus strains by hemagglutination-inhibition tests with chicken antibodies.

Twenty strains of Venezuelan encephalitis (VE) virus inoculated intravenously in large doses into roosters produced hemagglutination-inhibition (HI) antibodies detectable in plasmas within 7 to 10 days. No signs of illness occurred, and there was no evidence of viral growth in tissues since blood concentrations of infectious virus steadily decreased after inoculation. HI antibodies in early plasmas were specific for VE virus and did not cross-react significantly with two other North American alphaviruses, eastern and western encephalitis viruses. VE virus strains could be distinquished by virus-dilution, short-incubation HI, but not by plasma-dilution neutralization tests, by using early rooster antibodies. The distinctions by HI test were similar with some strains to, but different with other strains from, those described by Young and Johnson with the spiny rat antisera used to establish their subtype classifications of VE virus (14, 28). Nevertheless, results of HI tests with rooster antibodies correlated with equine virulence, as did results with spiny rat antibodies, and distinguished the new strains of virus that appeared in Middle America during the VE outbreak of 1969 from preexisting strains.

Animals↗
PubMedDate not supplied

[Bovine diarrhea virus: an update].

Bovine Viral Diarrhea Virus (BVDV) is a pathogen of cattle, member of the family Flaviviridae, genus pestivirus, which also includes Classical Swine Fever Virus (CSFV, or hog cholera virus), and Border Disease Virus of sheep (BDV). It causes important economical losses associated mainly with reproductive failure. Pestiviruses are small enveloped viruses, with a diameter of about 40 nm. The nucleocapsid is probably icosahedral . The genome consists of a single stranded positive RNA, encoding approximately 430 kD of proteic product. Genetic expression consists of the synthesis of a polyprotein which is co- and post-translationally processed. According to its behavior "in vitro" two biotypes can be distinguished: non cytopathic (ncp) and cytopathic (cp), most probably derived from the ncp through mutations and/or recombination. BVDV is able to cross the placenta and infect the fetus, causing a variety of problems, from fetal death to the birth of a persistently infected (P) calf, according to the fetal age at the time of infection. PI animals are immunotolerant to the virus and shed it in all secretions. Only the ncp biotype has been isolated from PI animals. The superinfection of a PI animal with a cp strain causes mucosal disease, always fatal. Outbreaks of a severe, sometimes hemorrhagic disease, caused by ncp BVDV, have occurred in Canada and USA since 1993. Genomic and serological differences between the "traditional" strains and the viruses isolated from these outbreaks led to the division of BVDV in subtypes I and II, both including cp and ncp strains. Analyses of the non coding 5'-UTR zone of the genome of pestiviruses from different species (bovine, ovine, porcine) suggest that there are at least 3 genotypes within the genus. A new classification of these viruses, based on genomic sequence instead of species of origin, has been proposed. Genomic heterogeneity exists in the BVDV genome, which presents 3 hypervariable zones, 2 of them in the major neutralizing protein. In Argentina prevalence of BVDV antibodies in cattle population is 70%, and the prevalence of persistent infections is around 1%.

Abortion, Veterinary↗
PubMed1978

Razdan virus, a new ungrouped bunyavirus isolated from Dermacentor marginatus ticks in Armenia.

A virus, designated Razdan, was isolated from Dermacentor marginatus ticks in the Armenian S.S.R. in 1973. The complement fixation tests revealed no antigenic relationships to 74 tick-borne arboviruses. The size of the virus is about 100 nm; it agglutinates goose erythrocytes at pH 5.5--7.0, is pathogenic for newborn, 14-day-old and adult white mice and multiplies in primary and continuous cell cultures. Morphological properties of the virus permit its classification as a member of the family Bunyaviridae.

Animals↗
PubMed1998

Taxonomy of African horse sickness viruses.

Nine distinct genera are currently recognised within the virus family Reoviridae, which include a total of 63 virus groups or species (species = virus group = electropherotype or serogroup), comprising 214 virus serotypes or subtypes, as well as 20 provisional types or subtypes, most of which (149 + 9 tentative) are assigned to the genus Orbivirus [5, 9, 16]. The 19 species of orbiviruses (serogroups), were established principally on antigenic (serologic) grounds but many of these placements have been supported by molecular analyses. This introductory paper defines the taxonomy and classification of these viruses and establishes guidelines for use in other paper to be presented at this symposium and elsewhere.

African Horse Sickness↗