13 September 1985
It is unknown when AIDS emerged.  However, the first reported cases were in the early eighties. Then, the disease was widely known as a gay man’s disease because it was first detected in homosexual males. It is now believed that the disease first emerged as far back as the 1960’s. On 13 September 1985, the World Health Organisation (WHO) declared the disease a worldwide epidemic. Africa has the highest rate of infection than any continent, with South Africa having the highest of any country. According to the United Nations Programme on HIV and AIDS (UNAIDS), 22.4 million people in Sub Saharan Africa were living with the disease in 2009, making it the most heavily affected region.
References

Avert "History of Aids up to 1986" from avert [online] Available at: www.avert.org [Accessed on 31 August 2012]|

UNAIDS "East and Southern Africa" from ;UNAIDS[online] Available at: www.unaids.org [Accessed on 31 August 2012]">