A rising number of dual infections with HIV and tuberculosis has created a co-epidemic spreading throughout sub-Saharan Africa, researchers say.
Poor areas of sub-Saharan Africa are vulnerable
Local health systems are unable to contain the co-epidemic, the Forum for Collaborative HIV Research says.
The situation is made more urgent by increasing rates of drug-resistant TB in areas with a high prevalence of HIV.
Half of all new TB cases in sub-Saharan Africa are now HIV co-infected, forum director Veronica Miller said.
TB, which is a disease of the respiratory system, is not uncommon - about 20% of the world's population has it but most will not develop the disease.
However in Africa's slums, where people live crammed together in tin shacks, TB is rife, the report notes.
Because HIV has destroyed the immune systems of at least a quarter of the population in some areas, far more people are not only developing TB but spreading it to otherwise healthy neighbours.
The BBC's Peter Greste in Cape Town says areas around the South African city are among the worst affected.
In one community in the western Cape, a child is 100 times more likely to contract TB than anyone living in the developed world.
But one Cape Town-based researcher, Dr Stephen Lawn, says existing tests often cannot spot TB before it is too late and health care systems cannot cope.
Without proper treatment, the Forum for Collaborative HIV Research says, 90% of people with HIV die within months of contracting TB.