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1、,第26章 肝炎病毒,指侵犯人体肝细胞为主，并引起肝炎的病毒，有甲、乙、丙、丁、戊等种类,肝炎病毒,中国不仅是一个人口大国，而且也是病毒性肝炎的高发区。目前已知的甲、乙、丙、丁、戊、庚及TTV型肝炎，在我国均有发生，其中尤以甲、乙、丙、戊4个型别的流行情况严重。 仅乙肝病毒携带者以达1.2亿之多。可以说，病毒性肝炎是对我国危害最为严重的传染病。,甲型肝炎病毒（HAV)人类甲型肝炎,病毒形态： 球形，直径2729nm,核心为RNA 抵抗力： -20。C可存活多年 25。C至少活1个月 毛蚶体内60。C耐受10 h 漂白粉和次氯酸钠可消除传染性,H Hepatitis A V Virus,HAV,
2、HAV的结构,甲型肝炎病毒,主要传染源：病人、隐性感染者 传染方式：粪-口（fecal-oral） 致病机理：,病毒进入机体,肠粘膜和局部淋巴结增殖,入血形成病毒血症,入肝并在内增殖，引起肝细胞病变,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,HAV在体内的散播,甲型肝炎有何症状？,通常有近1个月的潜伏期。 病人起病急骤。开始有畏寒、发热、腹泻、腹痛、咽痛、关节痛等症状。接着出现厌食，特别是厌油腻，全身无力、恶心、呕吐，右上腹部的肝区，感到疼痛。 检查时，可以发现病人肝肿大。化验
3、检查肝功能，可有血清“谷丙转氨酶”(简称ALT)升高。,症状（2）,几天以后，多数病人会出现黄疸，眼睛的巩膜（即“白眼珠”）和皮肤发黄，尿为浓茶色，大便颜色变浅，皮肤瘙痒。这个时期称为“黄疸期”。 黄疸持续大约1个月后逐渐消退，其他症状也逐渐消失，肝功能恢复正常。,甲型黄疸性肝炎急性期 巩膜黄染,甲型肝炎病毒,免疫性： 相应抗体IgM、IgG, 都对HAV的再感染有免疫作用 IgM持续2个月左右， IgG可持续多年 微生物学检查：测定HAV-AbIgM有助于早期诊断,A blood test (IgM anti-HAV) is needed to diagnose hepatitis A,特异
4、性预防prevent hepatitis A virus,甲肝活疫苗 获得免疫力持久,甲肝预后,预后良好,一般不转为慢性。 但需防止肝功能衰竭出现！,PERSONS WHO SHOULD RECEIVE HEPATITIS A VACCINE Persons traveling to or working in countries that have high or intermediate rates of hepatitis A Children in communities that have high rates of hepatitis A and periodic hepatiti
5、s A outbreaks Illegal-drug users Persons who have occupational risk for infection Persons who have chronic liver disease Persons who have clotting-factor disorders,How long does immunity last after hepatitis A vaccination? Although data on long-term protection are limited, estimates based on modelin
6、g techniques suggest that protection will last for at least 20 years.,Can other vaccines be given at the same time that hepatitis A vaccine is given? Yes. Hepatitis B, diphtheria, poliovirus (oral and inactivated), tetanus, oral typhoid伤寒, cholera, Japanese encephalitis脑炎, rabies, yellow fever vacci
7、ne or immune globulin can be given at the same time that hepatitis A vaccine is given, but at a different injection site.,When are persons protected after receiving hepatitis A vaccine,Protection against hepatitis A begins four weeks after the first dose of hepatitis A vaccine.,Can hepatitis A vacci
8、ne be given after exposure to hepatitis A virus?,No, hepatitis A vaccine is not licensed for use after exposure to hepatitis A virus. In this situation, immune globulin should be used.,Can hepatitis A vaccine be given to immunocompromised persons? (e.g., persons on hemodialysis or persons with AIDS)
9、 Yes.,Can hepatitis A vaccine be given during pregnancy or lactation? We dont know for sure, but because vaccine is produced from inactivated hepatitis A virus, the theoretical risk to the developing fetus is expected to be low. The risk associated with vaccination, however, should be weighed against the risk for hepatitis A in women who may be at high risk for exposure to hepatitis A virus,
