TB a global emergency

the disease. It is the biggest killer of people living with HIV/Aids in Africa. Almost half a million people develop multi drug-resistant strains of the disease every year, writes Jean François Saint-Sauveur.
Twin epidemics of HIV and TB are spreading illness and death, especially in Africa.
Today, an estimated 12 million people are co-infected with these diseases and more than two thirds of them live in sub-Saharan Africa. Without treatment, about 90 percent of people with HIV who become infected with TB will die within months of contracting the disease.
TB was drastically reduced in wealthy countries over 40 years ago. TB control programmes, however, have failed to wipe out the disease in developing countries, where today, 99 percent of TB deaths occur.
In Zimbabwe, official figures show that the incidence of TB has increased exponentially from 97 cases per 100 000 people in 2000 to 742 cases per 100 000 in 2007.
However, less than 40 percent of cases are detected and, therefore, treated. Successful cure rate is 74 percent of those treated. These figures illustrate the long and hard way ahead.
In our field experience in Zimbabwe, one of the biggest health challenges is the consequences of migration in the treatment and follow up of patients, not to mention the risk of spreading multi-drug resistant TB (MDR-TB) or, in the worst case scenario, extensively drug-resistant TB (XDR-TB) in the Sadc region due to default treatments.
High proportion of TB/HIV patients are lost to follow up due to migration to countries like South Africa and Botswana in search for employment opportunities. Likewise, there are considerable numbers of patients initiated on anti TB treatment in South Africa who present to Zimbabwe’s health structures for re-supply of TB drugs posing challenges in forecasting TB drugs consumption statistics for the districts.
TB is a contagious disease that spreads mainly through the air like a common cold, usually affecting the lungs. This form of the disease (pulmonary TB) is characterised primarily by a persistent cough, shortness of breath, weight loss and night sweats.
Only one in 10 people infected by the bacteria will actually go on to develop the disease, because a healthy immune system will keep the infection dormant. But these infections can reactivate decades later if the immune system becomes weak.
MSF staff and other treatment providers around the world are facing a double crisis in the TB medical programmes: on the one hand, there is a growing number of patients infected with new strains of TB that are resistant to standard treatments and on the other, there is a rapid spread of TB among people living with HIV/Aids. The situation is made worse by the lack of reliable, rapid ways to diagnose TB, and doctors are often forced to make treatment decisions without a definitive diagnosis.
Lack of suitable diagnostic methods
The most widely used technique for diagnosing active tuberculosis is sputum smear microscopy: a person suspected to have TB produces a sputum sample, coughed up from their lungs, that is examined under a microscope for evidence of TB mycobacteria.
While this method is cheap and easy enough to use in all but the most remote areas, it is not a very sensitive test and detects less than half of all active TB cases. In addition, people with extra-pulmonary TB (infection outside the lungs) and children go undetected by this method.
As a result, people can be given the wrong treatment that not only puts their own lives at risk but also allows the TB mycobacteria to develop resistance to the drugs. Such drug-resistant strains, in turn, pose a grave threat to others who could contract them.
More sophisticated and sensitive techniques exist for diagnosing TB, but they are often either very expensive or not suitable for use in the settings where most people with TB live and where MSF works.
Drug-resistant strains
Testing for TB with a microscope can at best only reveal whether the TB mycobacteria are present or not in the sputum of a patient. In the case of people with drug-resistant TB, further tests are necessary to pinpoint the particular resistant strain infecting the patient. This can only be carried out at present by growing the bacilla in a well-equipped laboratory. The bacilla then have to be tested to find out which drugs they are resistant to again in laboratory conditions.
Drug resistance can be more rapidly detected by new molecular tests but these again require excellent laboratory conditions. These kinds of diagnostic tests just can’t be done in remote areas. The length of time it takes to get the results through means many patients don’t get the correct treatment in time.
What is alarmingly clear is that the rate of drug-resistant strains is rising rapidly among people living with HIV/Aids, particularly in Southern Africa.
HIV co-infection
Diagnosing TB in people who are HIV positive is also extremely difficult because there are less bacteria in their sputum and the disease is more prevalent outside the lungs in these cases. The result is that many patients will go undetected until it is too late.
Without adequate diagnosis, the disease continues to kill and spread at an alarming rate in regions already hit by a high prevalence of HIV. Resistant forms also spread easily in conditions where weak health infrastructure and weakened immune systems are both common.
HIV has been fuelling the TB epidemic throughout Africa. In Lesotho, where MSF runs an HIV care project in a rural health centre, 221 patients started on TB treatment in 2006, 92 percent of whom were co-infected with HIV.
While Multi-drug resistant TB (MDR-TB) might be deadly in 5-20 percent of HIV-negative patients, death rates of 66 percent have been reported among HIV-positive patients. One reason is that some of the drugs used to treat both conditions interact, reducing their effectiveness and may trigger serious side effects.
XDR-TB: Virtually no options
In 2006, the world received a dramatic wake-up call about the dangers of drug-resistant TB in places where HIV is present.
In the KwaZulu Natal province of South Africa, a group of people were identified as having an extensively resistant strain of TB (XDR-TB) that responded to nearly none of the known TB treatments.
Fifty out of the 53 people infected with this more deadly strain died within a space of a couple of weeks even before their diagnosis was confirmed. Forty-four of those tested were HIV positive. The combination of XDR-TB and HIV infection is particularly dangerous because due to the difficulties of diagnosing TB in HIV patients, diagnosis is often delayed to a point where the patient is too sick to respond to treatment.
In fact MSF had already been treating patients with XDR-TB in Eastern Europe for several years. The alarming fact was the rapid spread of this drug-resistant strain to countries with high HIV prevalence which lead therefore to even higher death rates. Up to now, XDR-TB cases have been identified in more than 40 countries.
What health workers and patients need
It is important that the medical community continues raising the alarm with governments and other international bodies about the inadequacy of the present tools to tackle TB – both drug-sensitive and drug-resistant forms – and press for TB to be established as a health priority worldwide.
TB is a global emergency, yet health workers are struggling to tackle the crisis without access to the medical tools they need – both adequate diagnostics and treatments are desperately lacking. TB research demands a new model for R&D so that TB and other diseases that mostly affect the poor and their communities aren’t neglected as happens now as a result of the present profit driven system.
TB research also needs greater funding.
Given that around US$950 million needs to be invested annually in the development of new tools, but only just over US$200 million was invested in 2005, there must be much greater financial commitment to TB by governments and international bodies.
In addition, the research community and regulatory agencies must explore ways to accelerate drug development, for example through drug trials in drug resistant patients to get promising new drugs to people in need faster.
In practical terms, what health workers and patients need are:
1- New diagnostic tools which are simple, reliable, and adapted for use in remote, resource-poor settings and by the trained health workers at these levels
2- More potent drugs to shorten the length of treatment to only a few weeks and to address drug-resistant TB
3- Drugs that do not negatively interact with AIDS drugs, for people co-infected with HIV
4- In the longer term, we need an effective vaccine to protect against the disease
5- A clear referral system for TB patients at Sadc regional level to prevent default treatments
In 2010, MSF treated close to 30 000 people for tuberculosis, of which 3 300 were children under the age of 15.
MSF – often working alongside national health authorities – treats patients for TB in 29 countries in a wide variety of settings, ranging from urban slums to rural areas, prisons or refugee camps.
In recent years, MSF has worked to increase the numbers of people it treats with drug-resistant tuberculosis from 11 patients in 2001 to around 1 000 people across 15 countries in 2010.
Jean François Saint-Sauveur, MD, MPH, is MSF’s Medical Co-ordinator in Zimbabwe