[Human immunodeficiency virus (HIV)--a new name for the AIDS-causing virus. Suggestion for a system of classification of HIV infections].
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Acquired Immunodeficiency Syndrome↗
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[Classification and nomenclature of vertebrate animal viruses].
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International Cooperation↗
Genetic diversity of BVDV: consequences for classification and molecular epidemiology.
Genetic typing of bovine viral diarrhoea virus (BVDV) is important for the precise classification of viruses as well as for the development of molecular epidemiology. BVDV isolates were usually typed based on comparison of genomic sequences from the 5'-untranslated region (5'-UTR), N(pro) and E2 region. Recently we have identified 11 genetic groups (subgenotypes) of BVDV-1. Our further experiments confirmed a new subgenotype, BVDV-1k, isolated from cattle in Switzerland. BVDV isolates from India were typed as BVDV-1b whereas BVDV-1c is a predominant subgenotype in Australia. The results of genetic typing of BVDV indicate that distribution of subgenotypes has no relationship to the geographic origin of viral isolates.
Animals↗
Hepatitis C virus variants from Nepal with novel genotypes and their classification into the third major group.
Five isolates of hepatitis C virus (HCV) RNA from patients with chronic liver disease in Nepal were not classifiable into the known genotypes I/1a, II/1b, III/2a, IV/2b or V/3a using PCR with type-specific primers deduced from the HCV core gene. Their nucleotide sequences were determined for the 5'-terminal 1.5 kilobases and 3'-terminal 1.2 kilobases, covering 30% of the entire genome, and compared with each other and with reported sequences of HCV isolates of various genotypes. They were more similar to a reported HCV isolate (NZL1) of genotype V/3a (in 81.6 to 84.1% of their nucleotides and 85.7 to 88.7% of the deduced amino acid sequence) compared with the genotypes I/1a to IV/2b (in 69.3 to 74.7% and 72.3 to 77.4%, respectively). Hence they were considered to be variants of the third major group (group 3). The five HCV isolates shared 81.3 to 85.2% of nucleotide sequence and 85.4 to 89.3% of deduced amino acid sequence. Thus they were substantially different from each other. One of them was classified as genotype VI/3b due to an 88.2% similarity in nucleotide sequence to that of the reported HCV isolates of this genotype, whereas the remaining four were classified into provisional genotypes 3c, 3d, 3e and 3f. These HCV variants have evolved and remained in Nepal, and have not been observed in the other areas of the world.
Amino Acid Sequence↗
Molecular epidemiology of DNA viruses: applications of restriction endonuclease cleavage site analysis.
Restriction endonucleases which cleave DNA at specific nucleotide sequences can be used to produce a set of DNA fragments of a viral genome which, when separated by gel electrophoresis, gives a characteristic "fingerprint" for that virus genome. This simple technique has been used to identify and classify DNA viruses of the herpes, adeno, and papova virus groups. Small variants within a given type (e.g., herpes simplex type I) are genetically stable and permit study and identification of individual strains of viruses. Such analyses have recently been applied to study the epidemiology of some DNA virus outbreaks. Restriction endonuclease fingerprinting provides a useful addition to methods for virus identification and classification.
Cytomegalovirus↗
Geographic distribution and serologic and genomic characterization of Morro Bay virus, a newly recognized bunyavirus.
More than 75,000 immature mosquitoes in three genera were collected from coastal California, reared to the adult stage, and tested for virus by plaque assay in Vero cell cultures. Twenty-six strains of Morro Bay (MB) virus, a newly recognized member of the California (CAL) serogroup, were isolated from Aedes squamiger, a pestiferous salt marsh mosquito species restricted to intertidal salt marshes in coastal California and Baja California. The geographic distribution of the isolates was 10 from San Luis Obispo County, one each from Santa Barbara and Orange Counties, and 14 from San Diego County. No virus isolations were made from 23,157 Ae. squamiger collected north of San Luis Obispo County (midpoint in the geographic range of this species in California). Thus, MB virus infection in Ae. squamiger appears to be restricted to the southern range of this species in California. Serum dilution neutralization tests indicated that MB virus represents a novel subtype of the California encephalitis (CE) serotype within the CAL serogroup. Comparative analyses of genomic sequence data from four geographically distinct MB virus isolates indicated that the isolates are genetically similar to each other and distinct from other CE serotype bunyaviruses. Phylogenetic analysis of nucleocapsid protein gene sequence data indicated that MB virus represents a distinct lineage within the CE serotype and thus supports the serologic classification of MB virus as a distinct CAL serogroup virus.
Aedes↗
Influenza A viruses isolated from migrating ducks in Oklahoma.
Nine type A influenza viruses were isolated from migrating and wintering ducks in Oklahoma in 1976-77. Antigenic classification of the viruses isolated revealed three different subtypes: Hav1 Nav2, Hws N1, and Hav6 N2. Transmission of influenza viruses from the wild ducks to sentinel birds (McGraw mallards) on the same lakes was not detected.
Animals↗
Rabbit hemorrhagic disease virus--molecular cloning and nucleotide sequencing of a calicivirus genome.
The RNA genome of rabbit hemorrhagic disease virus (RHDV) was molecularly cloned. The 5' terminal sequence of the genomic RNA was determined after PCR amplification of a G-tailed first strand cDNA template. The cloned cDNA allowed determination of the first complete caliciviral sequence encompassing 7437 nucleotides without poly(A) tail. The RHDV genome contains one long open reading frame of 2344 codons which in the 5' region encodes the nonstructural proteins. Sequence comparison studies revealed significant homology between nonstructural proteins of the feline calicivirus (FCV) and RHDV. In analogy to FCV the deduced RHDV amino acid sequence contains a picornavirus 2C-like sequence, a hypothesized cysteine protease motif, and the conserved polymerase residues GDD. For the protein region containing the GDD motif, alignments of sequences from different viruses including the putative caliciviruses hepatitis E virus and Norwalk virus were performed; concerning the classification of the latter two viruses, a final judgement was not possible. Bacterial expression of sequences derived from the 3' part of the genomic RHDV RNA showed that this region codes for the viral capsid protein.
Amino Acid Sequence↗
[An introduction to the study of slow virus diseases of animals. Comparative pathology and etiology. Attempted classification].
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Animals↗
Genetic variability of immunomodulatory genes in ectromelia virus isolates detected by denaturing high-performance liquid chromatography.
The genetic variability of nine genes in 12 isolates and strains of ectromelia virus, which causes a smallpox-like disease (mousepox) in mice, was determined and allows for classification of ectromelia viruses. The low genetic variability suggests that evolutionary pressure maintains the activity of immunomodulatory genes in natural poxvirus infections.
Amino Acid Sequence↗
Sequencing of porcine enterovirus groups II and III reveals unique features of both virus groups.
The molecular classification of the porcine enterovirus (PEV) groups II and III was investigated. The sequence of the almost complete PEV-8 (group II) genome reveals that this virus has unique L and 2A gene regions. A reclassification of this group into a new picornavirus genus is suggested. PEV group III viruses are typical enteroviruses. They differ from other enteroviruses by a prolonged stem-loop D of the 5'-cloverleaf structure.
3' Untranslated Regions↗
Characterization of virus infected cell cultures by pyrolysis/direct chemical ionization mass spectrometry.
The supernatants of Vero cell cultures after infection with a herpes simplex virus or a poliomyelitis virus as well as a blank were analysed by pyrolysis/direct chemical ionization mass spectrometry (Py/DCI MS). Informative pyrogrammes were obtained and used for characterization of viral proteins by applying pattern recognition methods. Differentiation of viral proteins was evaluated by analysing 'blind' samples. Herpes viruses could be classified correctly but the observed differences between the blank and the polio virus supernatants were too small for reliable classification of the polio viruses. Purification of the samples seems to be a prerequisite for further studies. The potential value of Py/DCI MS as a rapid non-invasive diagnostic method for viral meningoencephalitis is stressed.
Animals↗
Molecular characterization of positive-strand RNA viruses: pestiviruses and the porcine reproductive and respiratory syndrome virus (PRRSV).
Molecular characterization has become an important tool for the analysis of viruses including their classification. The manuscript focuses on the molecular analysis of two members of the genus pestivirus (hog cholera virus, HCV and bovine viral diarrhea virus, BVDV) and of the recently discovered porcine reproductive and respiratory syndrome virus (PRRSV). The first protein encoded within the single large pestivirus ORF is a nonstructural protein with autoproteolytic activity. The cleavage site between the protease and the capsid protein p14 has been predicted previously, but recent experimental data indicate that processing occurs at a different site. The capsid protein is followed by a putative internal signal sequence and three glycoproteins which are part of the virion envelope. According to a new proposal for the nomenclature of the structural proteins of pestiviruses they are termed C, E0, E1 and E2. The genomes of BVDV pairs isolated from animals which came down with mucosal disease were analyzed. The genomes from cytopathogenic (cp) BVD viruses may contain insertions highly homologous to cellular sequences. In addition, cp BVDV may differ from its non cytopathogenic (noncp) counterpart by mere rearrangement of viral sequences. The disease PRRS, which emerged a few years ago, is caused by a single strand RNA virus; the viral genome is of positive polarity and has a size of 15 kb. Data concerning morphology, morphogenesis and virion composition suggested already that PRRSV belongs to a group of so-called arteriviruses which comprises equine arteritis virus (EAV), lactate dehydrogenase elevating virus (LDV) and simian hemorrhagic fever virus (SHFV). This conclusion has now been confirmed by analysis of genome organization, gene expression strategy and by comparison of deduced protein sequences.
Amino Acid Sequence↗
Group-specific antigens of RNA tumor viruses as markers for subinfectious expression of the RNA virus genome.
Antigenic markers associated with the major internal protein of RNA tumor viruses of the C-type have proven extremely useful in natural history studies of these viruses. This protein possesses species-specific antigenic determinants, and, in the case of mammalian C-type viruses, the protein possesses crossreactive determinants as well. These determinants are, thus, useful for species identification and classification of mammalian viruses. A unique distribution of antigens in embryonic tissues of several species (where tests are available) was detected, and in addition, antigen expression in tissues appears to be controlled by a dominant gene. These data have contributed greatly to the theory that RNA tumor-virus information is inherited as part of the cellular genome.
Animals↗
Characterization of Triatoma virus, a picorna-like virus isolated from the triatomine bug Triatoma infestans.
Some properties of Triatoma virus (TrV), a picorna-like virus recently isolated from Triatoma infestans, have been studied. Electron microscopic observations of purified viral preparations showed the presence of non-enveloped viral particles 30 nm in diameter. The sedimentation coefficient of virus particles was about 165S and the buoyant density in CsCl was 1.39 g/ml. The viral genome was composed of one single-stranded RNA molecule with an Mr of 3 x 10(6). Three major polypeptides with Mr values of 39K, 37K and 33K and a minor one of about 45K were found in the virus particle. TrV particles contain about 35% RNA and 65% protein by weight. These data support the classification of this virus in the family Picornaviridae.
Animals↗
Classification system for human T-lymphotropic virus type III/lymphadenopathy-associated virus infections.
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Acquired Immunodeficiency Syndrome↗
[Does virus diagnosis open new ways for the classification and treatment of sudden deafness, unilateral vestibular loss and idiopathic facial paralysis?].
Paired sera from 51 patients with sudden deafness, 21 patients with acute vestibular loss and 28 patients with Bell's palsy were examined for antibodies against mumps-, echo-, herpes simplex- and coxsackie viruses. Only two serum samples showed a significant titer increase or decrease. So viral etiology of sudden deafness, acute vestibular loss and Bell's palsy seems to be unlikely and does not change the assignment and therapy of this disease.
Antibodies, Viral↗
Pathogenetic differences between coxsackie A and B virus infections in newborn mice.
Coxsackieviruses are divided into A and B subgroups on the basis of their pathogenicity in newborn mice. Although used in the classification of these viruses, our understanding of the details of the infection is incomplete due to the lack of sensitive and specific techniques to localize the viruses in affected tissue. We have used in situ hybridization to detect coxsackievirus genomes in tissues of newborn mice after infection by five serotypes (A2, A9, A21, B3 and B4) through different administration routes. Our results indicate that coxsackie A viruses are able to affect both skeletal and heart muscle while the coxsackievirus B subgroup infects a wide range of tissues. In addition to striated muscle these include central nervous system, liver, exocrine pancreas and brown fat. This model will make it possible to analyze molecular factors determining tissue tropism.
Animals↗