The 3,000 delegates will spend four days discussing the challenges posed by the dual epidemics of TB and HIV - which are still often treated separately although they feed off each other. About one-third of the world's 40 million people infected with the AIDS virus have TB, the vast majority of them in Africa. TB kills more than 1.6 million people every year.
"Unlike bird flu, the global threat of HIV/TB is not hypothetical. It is here now. But the science and coordination needed to stop it are utterly insufficient," said Veronica Miller, director of The Forum for Collaborative HIV Research, in a report released ahead of the Cape Town conference.
The only available vaccine was invented more than 85 years ago and fails to protect most people beyond childhood. Antibiotics used to fight TB are more than 40 years old. Testing methods used in most developing countries were developed 120 years ago, are notoriously slow and often fail to spot TB in AIDS patients.
Health activists charge that rich countries and their pharmaceutical industries have shown little interest in developing more effective drugs because TB primarily affects poor people in poor countries.
In a report issued Wednesday, the New York based advocacy Treatment Action Group accused the United States and other donor nations of backsliding on commitments made last year to step up the fight against TB.
It said that international spending for TB research and development remained stagnant at US$413 million - less than half the amount called for in a much-vaunted 2006 Global Plan to Stop TB to increase funding for research on new TB diagnostics, drugs.
The contribution from the U.S. National Institutes of Health - the biggest funder - declined slightly to US$120 million, it said. Mark Harrington, executive director of the Treatment Action Group, said that with the U.S. budget problems and overspending in Iraq, TB wasn't "even on the radar" of the U.S. administration.
"Current funding levels for TB research and development are vastly out of proportion with the scope of the TB epidemic," said Dr. Mario Raviglione, Director of the World Health Organization's Stop TB Department.
The Treatment Action Group said the lack of funding was especially alarming given the global spread of multidrug resistant TB and extensively drug-resistant TB, which was identified in 2006 and is now present in more than 40 countries.
The spread of the drug resistant forms of TB is largely the result of poorly managed TB care and patients who don't take the full six-month course of treatment.
In South Africa, for instance, the cure rate for patients who stick to their treatment is just 50 percent, while WHO's target is 85 percent. In some areas, it is as low as 30 percent, according to Greg Hussey, head of the University of Cape Town's Institute for Infectious Diseases. People who are not properly cured are prone to develop multidrug resistant TB, which requires a two year treatment regimen.
South Africa hit the headlines last year when an outbreak of HIV and extensively drug-resistant TB was identified in 53 people at a clinic in Tugela Ferry in KwaZulu-Natal. All but one patient died within two weeks.
Because of the poor diagnostics, there are no reliable statistics on the number of South Africans who have been infected with extensively drug-resistant TB. The majority of them die before they can be tested or treated, according to Gilles van Cutsem, a project coordinator for Medecins Sans Frontieres in the poor Cape Town suburb of Khayelitsha, one of the hardest hit areas.
Little is known about the situation in neighboring countries like Swaziland and Mozambique, which also have high HIV and TB rates but don't have proper surveillance or laboratory facilities.