|
''Flavivirus'' is a genus of viruses in the family Flaviviridae. This genus includes the West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, and several other viruses which may cause encephalitis. Flaviviruses are named from the yellow fever virus, the type virus for the family; the word "''flavus"'' means "yellow" in Latin. The name "yellow fever" originated from its propensity to cause yellow jaundice in victims.〔The earliest mention of "yellow fever" appears in a manuscript of 1744 by Dr. John Mitchell of Virginia; copies of the manuscript were sent to Mr. Cadwallader Colden, a physician in New York, and to Dr. Benjamin Rush of Philadelphia; the manuscript was eventually reprinted in 1814. See: (Dr. John Mitchell) (written: 1744 ; reprinted: 1814) ("Account of the Yellow fever which prevailed in Virginia in the years 1737, 1741, and 1742, in a letter to the late Cadwallader Colden, Esq. of New York, from the late John Mitchell, M.D.F.R.S. of Virginia," ) ''American Medical and Philosophical Register'' … , 4 : 181-215. The term "yellow fever" appears on p. 186. On p. 188, Mitchell mentions "… the distemper was what is generally called the yellow fever in America." However, on pages 191-192, he states "… I shall consider the cause of the yellowness which is so remarkable in this distemper, as to have given it the name of the Yellow Fever." It should be noted, however, that Dr. Mitchell misdiagnosed the disease that he observed and treated, and that the disease was probably Weil's disease or hepatitis. See: Saul Jarcho (1957) "John Mitchell, Benjamin Rush, and Yellow fever," ''Bulletin of the History of Medicine'', 31 (2) : 132-6.〕 Flaviviruses share several common aspects: common size (40-65 nm), symmetry (enveloped, icosahedral nucleocapsid), nucleic acid (positive-sense, single-stranded RNA of approximately 10,000–11,000 bases), and appearance in the electron microscope. Most of these viruses are transmitted by the bite from an infected arthropod (mosquito or tick) and hence, classified as arboviruses. Human infections with these viruses are typically incidental, as humans are unable to replicate the virus to high enough titers to reinfect arthropods needed to continue the virus life cycle – man is a dead end host. The exceptions to this are yellow fever and dengue viruses, which still require mosquito vectors, but are well-enough adapted to humans as to not necessarily depend upon animal hosts (although both continue to have important animal transmission routes as well). Other virus transmission routes for arboviruses include handling infected animal carcasses, blood transfusion, child birth and through consumption of unpasteurised milk products. The transmission from animals to humans without an intermediate vector arthropod is thought to be unlikely. For example, early tests with yellow fever showed that the disease is not contagious. The known non-arboviruses of the flavivirus family either reproduce in arthropods or vertebrates, but not both. ==Taxonomy== Group: ssRNA(+) }}〔(【引用サイトリンク】title=Virus Taxonomy: 2014 Release )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flavivirus」の詳細全文を読む スポンサード リンク
|