Hepatitis A
什么是Hepatitis A？
Hepatitis is an inflammation of the liver caused by several viruses. There are three principal kinds of hepatitis, A, B, and C. Hepatitis A is caused by the hepatitis A virus, B by the B virus, and C by the C virus. Hepatitis A occurs worldwide as a sporadic or epidemic illness. It is ubiquitous in developing countries where adults are usually immune due to widespread exposure and mild illness acquired as young children.
如何获得Hepatitis A？
Hepatitis A is transmitted through contaminated food or water, including ice. It is also transmitted directly from person to person, from shellfish harvested in sewage-contaminated water, or from fruits, vegetables or other foods that are uncooked and that were contaminated during harvesting or subsequent handling.
易感性和抗性
Humans are generally susceptible to hepatitis virus infection. Life-long immunity follows natural infection with hepatitis A.
症状是什么？
Hepatitis A virus causes an inflammation of the liver manifested by the rapid onset of fever, fatigue, loss of appetite, nausea and abdominal discomfort. Within a few days, jaundice (yellow-coloured skin) appears. In children, the infection may be unapparent or very mild. The illness can be mild and last for 1-2 weeks or can be severely disabling and last several months. Prolonged or relapsing hepatitis may occur for up to 1 year in about 15 percent of the cases. Convalescence may be prolonged, but usually patients make a complete recovery. Chronic infection does not occur. Deaths due to hepatitis A virus infection occur in 0.1 to 0.3 percent of the cases.
预防措施
预防接种可预防甲型肝炎。在180°F或85°C下沸腾或烹饪食物和饮料超过1分钟，可使病毒灭活。水的氯化使病毒灭活。旅行者可以通过认真遵循食物和水的预防措施来降低风险。
处理
There is no specific treatment for acute hepatitis other than supportive measures.
When administered within 2 weeks of last exposure, hepatitis immune globulin is 80 to 90 percent effective in preventing clinical hepatitis A. In scientific studies, the use of the hepatitis A vaccine within 14 days after exposure provided protection equivalent to that of immune globulin.
疫苗接种
它常见于哪里？
甲型肝炎有高、中、低水平，低收入国家有高水平;中等收入国家有中低水平;高收入国家的甲型肝炎水平非常低。撒哈拉沙漠以南的非洲、印度和巴基斯坦的大部分地区都很高。在墨西哥、中美洲和南美洲、北非和整个中东地区都可以找到中等水平。东欧国家、俄罗斯和中国都发现低水平。在加拿大、美国、西欧国家和澳大利亚，其含量非常低。
