Sampathkumar Priya
Division of Infectious Diseases and Internal Medicine, Mayo Clinic, Rochester, Minn. 55905, USA.
Mayo Clin Proc. 2003 Sep;78(9):1137-43; quiz 1144. doi: 10.4065/78.9.1137.
West Nile virus was recognized in the United States for the first time in 1999, when it caused an epidemic of encephalitis and meningitis in New York City, NY. Since then, the disease has been steadily moving westward, and human cases were recognized in 39 states and the District of Columbia in 2002. The infection is caused by a flavivirus that is transmitted from birds to humans through the bite of culicine mosquitoes. Most infections are mild, with symptoms primarily being fever, headache, and myalgias. People older than 50 years are at highest risk of severe disease, which may include encephalomyelitis. In 2002, 5 new modes of transmission were recognized: blood product transfusion, organ transplantation, breast-feeding, transplacental transmission, and occupational exposure in laboratory workers. The transmission season was long, with cases occurring into December in some parts of the United States. Currently, there is no specific drug treatment or vaccine against the infection, and avoiding mosquito bites is the best way to protect against the disease.
西尼罗河病毒于1999年首次在美国被发现，当时它在纽约市引发了一场脑炎和脑膜炎疫情。从那时起，这种疾病一直在稳步向西蔓延，2002年在39个州和哥伦比亚特区发现了人类病例。该感染由一种黄病毒引起，通过库蚊叮咬从鸟类传播给人类。大多数感染症状较轻，主要症状为发热、头痛和肌痛。50岁以上的人患严重疾病的风险最高，严重疾病可能包括脑脊髓炎。2002年，人们认识到5种新的传播方式：输血、器官移植、母乳喂养、经胎盘传播以及实验室工作人员的职业暴露。传播季节很长，在美国一些地区病例会持续出现到12月。目前，针对这种感染没有特效药物治疗或疫苗，避免蚊虫叮咬是预防该疾病的最佳方法。
