By Fergus Walsh
Medical correspondent, BBC News
Tuberculosis is one of mankind's oldest foes.
TB can be treated with drugs
Although once a major killer in Europe and North America it is now largely a disease of poverty in the developing world.
For decades it became a neglected illness.
But in recent years the emergence of drug-resistant strains helped fuel an increase in cases in Europe and North America.
This has encouraged the international community to once again turn its attention to the bacterial infection.
It is estimated that one in three of the world's population is infected with TB.
Nearly nine million people a year fall ill from TB and more than one and a half million die from it.
The World Health Organisation estimates that nearly 500,000 people a year become infected with drug-resistant TB.
TB black spot
To see what is being done to tackle TB and view the latest research into the disease, there can be few better places than the Western Cape in South Africa.
The beautiful city of Cape Town has one of the world's highest TB rates, with the disease widespread in the township of Khayelitsha and other poor, densely populated areas.
Scientists at the University of Cape Town are at the forefront of TB research.
Researchers there have collected 800,000 blood samples from more than 10,000 volunteers as part of their bid to better understand TB and to develop better vaccines against it.
Professor Willem Hanekom, lab director at the South African Tuberculosis Vaccine Initiative (SATVI) has spent years studying the TB bacillus, which is spread by airborne droplets.
Professor Hanekom said: "It's easy to catch. If you live in the same house as someone with TB then there is a good chance you will be infected.
"In parts of South Africa where TB is common you can catch it on a train or in a shop when someone coughs up the bug."
That doesn't mean that you should avoid Cape Town for your holiday destination.
If a healthy person breathes in the bacteria then the immune system in the lung should respond and "wall off" the microbes.
The infected person does not fall ill and nor are they contagious. Instead the disease lies dormant.
This is what is known as latent TB.
Professor Hanekom said: "This is the horrible thing about the TB bug - it can live in people for ages and when they become malnourished or their immune system is weakened then TB can re-emerge and cause disease.
"It is an extraordinary bug and we're only just starting to understand it."
Overall, it is estimated that around one in 20 people will develop the disease within a year of being infected and another one in twenty will get TB later in life.
TB is curable, but the treatment lasts six months with a combination of antibiotic drugs.
Patients are usually not infectious within a few weeks of treatment and may feel much better.
This can encourage some to stop their treatment allowing drug-resistant strains of TB to emerge.
These are much harder and more expensive to treat.
GF Jooste Hospital in Cape Town is on the front line of TB control.
The hospital serves many of the poorest parts the city and admits around a dozen patients a day with active TB infection.
Associate Professor Robert Wilkinson, a Wellcome Trust senior fellow, showed me the X-ray of a patient with TB.
He said: "Tuberculosis can affect any organ, but usually it is the lungs.
"The classic symptoms are weight loss, fever, chronic cough and sometimes coughing up blood.
"In the lungs it often causes cavitation (a hole in the lung) but it can affect any organ in the body."
HIV worsens impact
On the ward, one of the TB patients was causing concern.
The patient's X-ray revealed bad news
Professor Wilkinson and Dr Graeme Meintjes, another TB specialist, reviewed his X-rays which showed a rare and incurable fungal infection on the lungs.
Dr Meintjes said that 80% of the patients admitted with TB are co-infected with HIV.
"The linking factor is that HIV depletes the immune system and the CD4 cells which are critical in defending the body against TB.
"In the past 10 years we have seen a four to five-fold increase in TB in sub-Saharan countries because HIV is driving the TB epidemic."
He said there is a stark contrast between the drugs available to fight HIV and TB.
"One of the biggest challenges for TB is that we use drugs that have been around for decades and there isn't the same promising pipeline of new drugs as there is for HIV.
"It reflects the fact that HIV is a common infection in the first world and there's not the same impetus to develop drugs for the third world."
In a consulting room Dr Meintjes introduced me to Jongiswa Makinana.
Jongiswa is 31 years old and has both HIV and extreme drug resistant XDR-TB.
This is an emerging problem in South Africa and many other countries.
In 2005 an outbreak in KwaZuluNatal among HIV patients killed 52 out of 53 people.
Nor surprisingly when Jongiswa was told she had XDR-TB she was distraught.
She said: "I told my doctor I was going straight to the train to kill myself. I felt there was no hope."
But after ten months in hospital Jongiswa is doing well.
She may be allowed home soon to her two young children in Khayelitsha.
"I told myself I must drink my medicine, not for my sake, but for my children."
The drug treatment for XDR-TB costs tens of thousands of dollars and lasts two years.
Jongiswa must take eight different medicines a day including an injection.
All these are in addition to the antiretroviral drugs she takes for HIV.
The global community is sadly feeling the effects of decades where TB was starved of research funds.
Things are changing according to Professor Greg Hussey of the Institute of Infectious Diseases and Molecular Medicine at UCT.
He said: "In terms of therapy we may have a few new drugs on the market in the next five to ten years.
"This may shorten treatment from six months to three or four months."
But Professor Hussey, who is also director of the South African TB Vaccine Initiative believes immunisation is the best hope of beating TB.
"As with any infectious disease, effective vaccines are of critical importance," he said.
"The only solution to defeating TB is to prevent the disease from occurring".