I don't have the explanation for why it's commonly translated as 艾滋病 for HIV and AIDS. I am assuming it is because a lot of people don't understand how they are related, thus the translation is often grouped together as the same thing (1). HIV: Short form translation would be 艾滋病病毒. Literally this means "AIDS virus". This is not necessarily correct as you have pointed out, but it is a common saying and will probably be easier understood by most people than 人体免疫缺损病毒 ( human immunodeficiency virus) (2). human: 人体 immunodeficiency: 免疫缺损 virus: 病毒 AIDS: Short form translation would be 艾滋病. Long form would be 获得性免疫缺陷综合征 (acquired immunodeficiency syndrome) (3). acquired: 获得性 (literally means "acquirable") immunodeficiency 免疫缺陷 (免疫缺损 works as well) syndrome: 综合征 Now, I don't know how often the translations I just gave you are in term of medical records. You will likely see multiple translations. For example, this dictionary that I have used shows AIDS as 获得性免疫缺乏综合征 (long), 艾滋病 (short) (4). However, this dictionary doesn't show accurate translation for HIV (it defined HIV as something else so I am not going to quote it here). I hope this helps :) Reference: (1) http://kidshealth.org/kid/health_problems/infection/hiv.html (2) http://dict.cn/hiv (3) http://dict.cn/aids (4) http://www.drdict.com/index.php?key=aids#.UcoFuTuG2FJ

Answer to the comment (for preserving the format): If I have misunderstood, please let me know. You meant patients who have either HIV or AID right? If so: AIDS patient: 艾滋病患者 儿童艾滋病患者 (lit: child AIDS patient) or 艾滋病儿童患者 (lit: AIDS child patient) HIV patient: HIV 患者 (1), 艾滋病病毒患者 (2), 艾滋病病毒感染者 (3), HIV感染者. For specifically referring to children, add "儿童" in front of the terms listed. For example, 儿童 HIV 患者. (1) Sometimes you will see the English abbr. instead of its full Chinese translation. (2) I am using "AIDS virus patient" rather than the full name as it is more natural and commonly used as compared to the full form. (3) 感染者 means "infected person".

In China we called AIDS 艾滋病. And HIV we say that is 艾滋病病毒 so AIDS is a sort of disease and HIV is a virus. HIV can lead to AIDS

我感觉大家对于这两个概念没有什么很深的了解，大家都更倾向于用“艾滋病”去概括他们。

acquired immunodeficiency syndrome 获得性免疫缺陷综合征