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California encephalitis virus was discovered in Kern County, California and causes encephalitis in humans. Encephalitis is an acute inflammation of the brain that can cause minor symptoms, such as headaches, to more severe symptoms such as seizures. Mosquitoes serve as its carrier and for this reason this virus is known as an arbovirus (arthropod-borne virus). California encephalitis virus belongs to the Bunyaviridae family of viruses. The La Crosse Virus from the same genus is also a common cause of encephalitis in the United States. Other viruses with similar disease symptoms but genetically unrelated include: St. Louis Encephalitis and West Nile Virus. ==History== It was first discovered and isolated in 1943, from mosquitoes collected in Kern County, California. Two years later the first human cases of encephalitis were attributed to this new virus. Three cases in total were reported, and all three cases were in residents of Kern County in the Central Valley of California. In all three cases there was strong laboratory evidence confirming infection, due to the presence of neutralizing antibodies linked to California encephalitis. Since then, most cases of encephalitis have been associated with the La Crosse virus, and California encephalitis is a rare cause of disease in the Western World.〔 The original California Encephalitis virus was isolated and put alongside fifteen other related viruses that are now categorized as the California serogroup. From 1996 to 1998, approximately three times as many reported human cases of arboviral encephalitis were caused by California serogroup viruses than were reported for western equine encephalomyelitis viruses, St. Louis encephalitis, and eastern equine encephalomyelitis viruses combined.〔 In the United States several factors influence the transmission and control of diseases of arboviral encephalitis, like those of the California Encephalitis virus. These factors include: the season, geographical location, patient age, and the regional climate condition such as spring or rainfall. There are approximately 75 cases reported per year.〔 The highest occurrence of arboviral encephalitis in the United States is in the Midwestern states, with most cases occurring in the late summer to early fall. Outdoor activities, especially in woodland areas, are associated with an increased risk of infection. Mortality rates are less than 1% and most patients with encephalitis clinical symptoms recover completely; however, 20% of patients develop behavioral problems or recurrent seizures.〔 Encephalitis disease in general occurs almost exclusively in children from 6 months to 16 years old. 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「California encephalitis virus」の詳細全文を読む スポンサード リンク
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