Showing papers on "Virus classification published in 1987"

Adeno-associated viruses: an update.

Abstract: Publisher Summary The adeno-associated viruses (AAV) are the only known DNA animal viruses that are absolutely dependent upon coinfection by a second unrelated virus to undergo productive infection. They are members of the family Parvoviridae , which are among the smallest of the DNA animal viruses. The Parvoviridae genome is a linear single-stranded DNA molecule approximately 5 kb in size, which is encapsidated in a naked icosahedral particle 18–27 nm in diameter. In addition to one genus of insect viruses (densoviruses), the family contains two genera that infect a broad spectrum of vertebrates ranging from birds to humans. The parvoviruses are able to replicate autonomously in infected cells but require actively dividing cells for a productive infection. Although the dependoviruses (AAV) are structurally similar to the autonomous parvoviruses, they are absolutely defective and require coinfection with structurally unrelated adenoviruses or herpesviruses for a productive infection to occur. Adeno-associated virus does not have any structural relatedness to either of its helpers; on the other hand, the three viruses do represent all of the known vertebrate virus families with linear DNA genomes that replicate in cell nuclei.

Classification and Nomenclature of Viruses

Abstract: Viral taxonomists have developed a system of classification and nomenclature that embraces all viruses. From the operational point of view, viruses are divided into those that affect vertebrate animals, insects, plants, and bacteria. The chapter discusses the viruses of vertebrate animals, although some of these viruses, the arthropod-borne viruses (arboviruses), also replicate in insects or other arthropods. Several hundred species of viruses have been recovered from humans, who are the best-studied vertebrate hosts and new ones are still occasionally discovered. Somewhat fewer have been recovered from each of the common species of farm and companion animals and from the commonly used laboratory animals. To simplify the study of this vast number of infectious agents, these are sorted into groups that share certain common properties. The most important criteria for classification are the physical and chemical characteristics of the virion and the mode of replication of the virus. The chapter explains a formal viral taxonomy, which is based on these criteria.

The molecular biology of the positive strand RNA viruses

Abstract: This book pulls together recent research findings on the molecular biology of the major families of positive strand RNA viruses infecting plants and animals The topics covered include protein translation, processing and function, RNA replication, virus structure and antigenicity, mechanisms of infection and evolutionary relationships between the virus families

Taxonomy and Comparative Virology of the Influenza Viruses

Abstract: Viral taxonomy has evolved slowly (and often contentiously) from a time when viruses were identified at the whim of the investigator by place names, names of persons (investigator or patient), sigla, Greco-Latin hybrid names, host of origin, or name of associated disease. Originally studied by pathologists and physicians, viruses were first named for the diseases they caused or the lesions they induced. Yellow fever virus turned its victims yellow with jaundice, and the virus now known as poliovirus destroyed the anterior horn cells or gray (polio) matter of the spinal cord. But the close kinship of polioviruses with coxsackievirus Bl, the cause of the epidemic pleurodynia, is not apparent from names derived variously from site of pathogenic lesion and place of original virus isolation (Cox-sackie, New York).

Chapter 5 Taxonomy of animal viruses

Abstract: Publisher Summary The present universal system for virus taxonomy is set arbitrarily at the hierarchical levels of family, genus, and species. The most important criteria for classification of viruses are morphology and physical and chemical nature of viral components. Virus families are designated by terms ending in - viridae . Families represent clusters of genera of viruses with apparently common evolutionary origin; for example, it seems unlikely that the very many similar structural and replicative characteristics of all the many diverse poxviruses could stem from more than one common ancestor. Virus genera are designated by terms ending in - virus . The criteria used to designate genera differ between families, and as more viruses are discovered there will be continuing pressures to use more specific physicochemical or serological differences to create new genera in many families. Virus species have not yet been designated formally. This level in the hierarchy of taxa will come to be regarded as equivalent to the present vernacular usage of the term virus.