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浙江大学传染病学试题(有答案）
一、名词解释（30％）
1、Relapse (Please answer in English)
After the patient has entered convalescent period, the temperature has recovered to normal for a period of time, then the pathogen hidden in some tissue reproduce to a certain degree and make the primary symptoms repeatedly, it is called “relapse”
2、Latent infection (Please answer in English and give some sample
When the microorganism infected the host and localized in some area of the host, it can latently for along time because the hosts immunity is strong enough to locate the pathogen but can wipes it out. When the hosts immunity decreased, overt infection can occurs. Such latent infection is common in some diseases, e.g. herpes simplex, herpes zoster, malaria, tuberculosis etc. Generally the microorganism can not be excreted during latent infection, which is a different point from carrier state. Not that every infectious diseases has latent infection.
3 cholera toxin（中文回答）
由霍乱弧菌分泌，引起剧烈腹泻。 霍乱毒素是典型的A-B亚单位型毒素，由1个A亚单位（CT-A）与5个B亚单位（CT-B）组成。CT-A又分为A1与A2片段，其中A1片段具有二磷酸腺苷-核糖基转移酶活性，可阻止 GDP水解，导致腺苷酸环化酶持续活化，使三磷酸腺苷不断转化为cAMP。细胞内cAMP浓度持续增高，刺激隐窝细胞分泌水、氯化物、碳酸氢盐的功能增强，同时抑制绒毛细胞对钠和氯离子的吸收，使水和氯化钠在肠腔积聚，引起严重的水样腹泻。
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