Yellow Fever
什么是Yellow Fever？
Yellow fever is a serious infectious disease that varies in the severity of illness. It is caused by the yellow fever virus. There are three types of yellow fever. One involves mosquitoes and non-human primates (monkeys) and is called jungle yellow fever since it occurs in forested rural areas. An intermediate type involves humans, primates and various types of mosquitoes in savannah regions of Africa. The third type is called urban yellow fever and involves humans and mosquitoes that are adapted to urban areas. In all three types, infected mosquitoes are the agents that transmit the disease to humans.
It is difficult to assess the risk of contracting yellow fever in the traveller since it depends on many different factors such as the traveller’s destination, the season, the work and recreational activities, as well as the local activity of the virus.
如何获得Yellow Fever？
Yellow fever is transmitted to humans through the bite of an infected mosquito.
易感性和抗性
Any unvaccinated person is susceptible.
Recovery from yellow fever is followed by lasting life-long immunity. Immunity in nursing infants born to immune mothers may persist for up to 6 months. In natural infections, antibodies appear in the blood within the first week. Yellow fever vaccination provides immunity for 10 years or more.
症状是什么？
Yellow fever is usually characterized by sudden onset of fever, chills, headache, backache, generalized muscle pain, prostration, nausea and vomiting. Jaundice (yellow skin) can occur early in the disease and progressively worsens later (20 to 50 percent of jaundiced cases are fatal). Most of the illness goes away following the early stage. Some cases progress, after a brief remission of hours to a day, to a stage that includes haemorrhagic symptoms including nose bleeds, bleeding from the gums, vomiting blood, black excrement, and liver and kidney failure. Around 5 percent of infected local populations will die, but that rate can reach 20 to 40 percent in individual outbreaks.
预防措施
接种疫苗可以预防黄热病。前往某些国家/地区需要接种证明书。如果旅行者要去或住在黄热病发地区，则也需要此证明。避免被蚊子叮咬也会减少黄热病的风险。
处理
Other than treatment of the symptoms, there is no specific treatment for yellow fever.
疫苗接种
它常见于哪里？
丛林黄热病在非洲从撒哈拉沙漠向南延伸至安哥拉北部、扎伊尔、尼日利亚和坦桑尼亚的地区。最近，喀麦隆、刚果民主共和国、几内亚和塞内加尔报告了病例。
在拉丁美洲热带森林地区，玻利维亚、巴西、哥伦比亚、厄瓜多尔、秘鲁和委内瑞拉报告了黄热病中间型病例。没有证据表明自1942年以来，美洲曾出现过城市黄热病。
没有证据表明黄热病在亚洲或非洲最东岸地区曾经出现过。
