Tuberculosis: an airborne disease.

In 1882, Robert Koch discovered the baccilli behind one of the world's oldest and most deadly diseases - tuberculosis (TB). That breakthrough led to the development of the first anti-TB treatment in 1944. The world breathed a sigh of relief.

Yet, despite advances in treatment, TB has made a comeback. The World Health Organization (WHO) predicts that some 30 million people will die of TB and 300 million more will become infected in the next ten years, and it has recognized this forgotten nemesis as the leading infectious killer of youth and adults today.

TB is an airborne disease, which can be spread by coughing, sneezing, talking or spitting. Dr. Paul Nunn, Chief of the Tuberculosis Research and Surveillance Unit of the WHO Global Tuberculosis Programme, describes the disease's contagious potential: "An individual who is sick with any strain of TB will infect 10 and 20 people each year with that same strain".

Factors contributing to the worldwide re-emergence of TB include increased migration, international travel and tourism; increased incidence of AIDS; the emergence of multi-drag resistance; and the weakening of public health care systems in both the developed and developing world, according to a recent report in The North-South Institute Newsletter.

Patients are partly to blame for TB's persistence. International health officials trace the emergence of multi-drug resistant TB (MDR-TB) to the failure on the part of patients to take their prescribed medication for the alloted time period. TB treatment spans six to eight months, but patients no longer feeling symptoms after two or three months often choose not to take their medicine. Others simply forget to take the drugs, or cannot afford their cost or the doctor's fee. Without sustained treatment, the TB bacilli has time to mutate and become resistant to standard drugs.

WHO has announced new management strategies to control TB, which will make it possible to save millions of lives and dramatically reduce the threat of multi-drug-resistant strains in the next decade. Known as DOTS (Directly Observed Treatment, Short-course), the new strategy encourages cooperation among doctors, health workers and primary health care agencies to ensure that the TB patient follows through with TB treatment until the TB bacteria is eliminated from the body. Once this happens, the patient can neither infect others nor develop MDR-TB.

According to a 1997 WHO report on the tuberculosis epidemic, the DOTS strategy has the potential to prevent up to 50 million deaths in the next several decades. The DOTS approach towards the epidemic is relatively simple, yet already it has met with astounding success. WHO estimates that "no other TB control strategy has consistently demonstrated such high cure rates. DOTS produces cure rates as high as 95 per cent, even in the poorest countries. TB programmes not using DOTS often cure only 40 per cent of their patients."

The cost effectiveness of implementing DOTS is a key reason why both industrialized and poor countries should install (if they have not already) this programme. WHO calculates that DOTS' cost, on average, is only $11 per patient in some areas of the world, and rarely exceeds $40 per patient. These findings suggest that Governments should extend funds for long-term TB control and develop or integrate a TB programme into their national agendas.

Hot Zones

WHO estimates that some 50 million people may have been already infected with drug-resistant TB. These figures are bolstered by a report, released on 22 October 1997, stating that "tuberculosis 'hot zones' are emerging around the world, where people are nearly helpless to protect themselves from drug-resistant strains, and which could soon ignite a new wave of virtually incurable tuberculosis worldwide". These "hot zones" include India, Bangladesh, South Africa and Russia.