HIV +ve entry restrictions to different countries:
http://answers.yahoo.com/question/index?qid=20071219135631AA7Zlll

recently in US, ban was lifted (jan 2010)

http://edition.cnn.com/2010/TRAVEL/01/04/us.hiv.visa/index.html

however, "HIV-infected visitors previously had to get a special waiver to obtain a visa" - may be only if coming for treatment