HIV/AIDS
AIDS is by far the leading killer in South Africa accountable for 46% (South African Medical Research Council) of all deaths totaling 380,000 deaths in 2005.  An estimated 1,200,000 children are left as orphans because of AIDS, a disease which claims roughly 1000 people per day.(1) Every day children become orphans, and only the lucky ones move on to already overcrowded, under funded orphanages.
Imagine an epidemic so huge that people don’t even have a place to bury their loved ones.(2)  Imagine an epidemic so catastrophic that even 21% of teachers, those that serve as role models for the future, are afflicted - the future whose children range from 240,000 infected to 500,000.(3,1)
There is no doubt that the country is struggling, though the efforts being put forth by both non profits and the government work together create a glimmer of hope.  South Africa is responsible for one quarter of all the people receiving antiretrovirals in sub-Saharan Africa, the most highly infected zone in the African continent.(4)

Tuberculosis
TB is the leading killer of those infected with HIV/AIDS. (Doctors without Borders).
Multidrug resistant (MDR) and Extreme Drug Resistant (XDR) strands of tuberculosis are becoming a growing problem as their prevalence rises with the widespread use of medication.  Again though, South Africa moves toward hope as both identification and treatment of the disease has improved dramatically.

Diarrhoeal Diseases
Nearly all diarrhoeal diseases (DD) can be stopped with a simple household mixture of salt, sugar, and water.  There is no reason this problem (most of us don’t even consider it a disease) should be the eighth highest killer.  And yet, DD is one of the leading causes of childhood mortality – 10% of deaths in children under 5 years old. HIV allows for the onset of DD, but the ultimate killer is this easily controllable disease.(5)

(1) –     UNAIDS/WHO 2006, UNAIDS 2006 Report on the global AIDS epidemic, Annex 2: HIV/AIDS estimates and data, 2005 - http://www.unaids.org/en/HIV_data/2006GlobalReport/default.asp
(2) –     The New York Times 2004, 29th July, 'South Africa 'recycles' graves for AIDS victims'
(3) –    UNAIDS/WHO 2006, UNAIDS 2006 Report on the Global AIDS Epidemic, Chapter 4: The impact of AIDS on people and societies
(4) –    UNAIDS/WHO, 2006

(5) – http://www.capegateway.gov.za/Text/2007/6/cd_volume_7_appendix_3_diarrhoeal_
disease.pdf