AIDS and monkeys
Here is a cached reprint of an old article in Nature and one from Science on AIDS and its origins in monkeys. The two main theories are it was transmitted by people eating monkeys and by culturing polio vaccine in monkey kidneys and vaccinating Africans in the Congo. Also the book reference is quite an interesting read.
http://www.google.com.au/search?q=cache:x1vJhqdtt2gJ:www.nature.com/cgi-taf/DynaPage.taf%3Ffile%3D/nature/journal/v397/n6718/full/397436a0_r.html+sabaeus+&hl=en&ie=UTF-8
http://www.lsa.umich.edu/psych/courses/darmed/sharp-HIVevol.pdf
http://www.amazon.co.uk/exec/obidos/ASIN/0713993359/o/qid%3D979319676/sr%3D2-1/202-7207047-2894263