Tuberculosis detection, treatment and control:
TB toll: two million lives annually
Dr P N B Wijekoon Consultant Chest Physician
President, CNAPT
Some facts about Tuberculosis
* TB is the leading infectious killer of adults worldwide.
* TB is responsible for 26 percent (more than a quarter of avoidable
adult deaths in the developing world).
* Left untreated, one person with active TB will infect 10-15 other
people in the space of a year.
* 1.7 billion people, one third of the world's population, are now
infected with the TB bacillus.
* An estimated two million people die from TB annually
* TB kills more adults each year than AIDS, malaria and tropical
disease combined.
* New outbreaks of Tuberculosis are now occurring in Eastern Europe,
where it had been on the decline for 40 years.
* Asian countries, with their large cities, high rates of TB bacillus
infection and growing spread of HIV currently account for two thirds of
all TB cases. In the industrialized nations, migration, international
travel and tourism are allowing TB to cross borders with ease (TB
doesn't need a visa)
* Of the 14 million people globally who were HIV positive in 1994,
5.6 million were believed to be infected with TB as well.
* TB is the leading killer of HIV – positive people, accounting for
almost one third of mortality worldwide and 40 percent in Africa. It
seems to be the leading opportunistic disease in 50-70 percent of AIDS
patients in Asia.
* As many as two-thirds of all HIV - positive people who seek
treatment is non-compliance where, drugs are not directly observed, to
be swallowed.
* Researchers estimate that almost 50 million people worldwide are
infected with resistant strains of TB.
* TB treatment can cost as little as $13 per person in some parts of
the world.
Tuberculosis is probably the most ancient and vicious foe the world
has ever had the misfortune to encounter. The disease has afflicted
mankind from the time man first evolved from the simian species (i.e;
the ape), proven by evidence of the disease in mummified remains of
Neanderthal man and Egyptian mummies. The disease has killed more people
than all the world wars combined, and depressingly, more people die of
the disease in the 21st century, despite astronomical advances in
medicare and therapeutics, than during any of the preceding millenia,
when no treatment at all was available.
Approximately 8-10 million people are infected by the causative
organism, mycobacterium tuberculosis, every year, worldwide. About four
million people actually develop the disease (not all people infected
develop the clinical disease, only about one third), and approximately
two million people die of the disease every year, more than the total
number of deaths caused by Malaria and AIDS combined.
Industrialized countries
Why do so many people contract the infection, develop the disease and
die? In a world - lethargy. Lethargy on the part of governments to spend
money for the detection, treatment and control of an unfashionable
disease they would prefer to ignore and sweep under the carpet, lethargy
on the part of medical students, doctors and their teachers to grasp the
fundamentals of the disease and its treatment, lethargy on the part of
patients to adhere to the correct number of drugs and prescribed length
of treatment and lethargy on the part of the pharmaceutical industry in
producing more effective drugs for what, to them, is a non-profitable
disease, because mostly poor people in poor countries (which cannot
afford to pay for the drugs), contract the disease.
The industrialized countries, having endured their own epidemics of
Tuberculosis in the 19th and previous centuries, apparently conquered.
The disease in the 20th century, mainly due to improved living
standards, nutrition and relatively effective treatment of infectious
cases. These countries then came to regard tuberculosis (somewhat
justifiably) as a disease confined to poor and undeveloped or developing
countries, and of no concern of theirs. Western pharmaceutical companies
followed suit, abandoning research on newer treatment modalities for the
disease.
Their victory, however, was short lived. Widespread emigration
(illegal and legal) from developing and less developed countries to the
West, and extensive, global air travel resulted in the disease becoming
global, with no one immune from contracting the infection. Emigrants,
harbouring the tuberculosis bacillus in their bodies, but not actually
suffering from the disease (therefore apparently completely healthy)
flooded industrialized countries in the latter path of the 20th century.
Western drug companies
As a result of extensive emigration - the stresses and strains of
living in a strange country and culture, sometimes on a hand - to -
mouth existence, caused many of these people to develop the actual
disease, which, when it affects the lung, is transmissible to other
people (though not all cases of pulmonary tuberculosis are infectious).
This is now happening in many industrialized countries, especially the
United States, United Kingdom and the Soviet Union, whose indigenous,
relatively defenceless (immunologically speaking), population is
contracting the disease with alarming frequency.
This phenomenon alarmed the West to such an extent that tuberculosis
was declared a global emergency by the WHO in 1995. Matters were made
worse because Western drug companies, usually the most active and
innovative of researchers, had ignored, for decades, developing more
effective drugs for the disease, which for them was a non-profitable
entity. Some of the drugs (like Streptomycin and Isoniazid), that are
still used for the treatment of the disease, originated as far back as
the 1950s.
Immune systems
Matters were made infinitely worse when the HIV epidemic exploded in
the latter part of the 20th century, almost totally wiping out the
immune systems in millions of people, worldwide. It is the immune system
that keeps the tuberculosis bacillus at bay, so that even if people are
infected by the organism, most of them do not actually develop the
disease, because of their intact immune systems.
They remain free of the disease for the rest of their lifespan,
though they harbour the bacillus in their bodies, as one third of the
world's population - 1,700 million people - do. In other words, 1,700
million people the world over are reservoirs for the disease, with the
potential of actually developing the disease and spreading it.
When some of these people contract HIV, their immune systems are
destroyed, and the tubercle bacillus explodes, causing severe,
widespread tuberculous disease affecting almost all the organs,
including the lungs, making the patient highly infectious. The
HIV/Tuberculosis duo is very appropriately labelled the 'cursed duet'
(or devilish pair), because each helps the other to destroy the patient,
and consequently, nations. This is actually happening now, as evidenced
by some countries in Sub - Saharan Africa, where million of productive,
young people have been wiped out by the dual epidemic, simultaneously
wiping out the economies of those countries.
Infectious disease
In a world where most diseases are becoming incurable (diabetes,
hypertension, Chronic kidney failure, Asthma, Ischemic heart disease,
cerebrovascular disease, cancer), tuberculosis remains eminently
curable. After all, it is merely an infectious disease, and infectious
diseases, in most instances, can be cured or controlled with antibiotics
or prevented by immunization.
The disease, when widespread in the community, profoundly damages the
economies in poor countries, because it is predominantly their young
(15-54 years age spectrum), productive workforce that is struck down by
the disease. Being young is the greatest plus point for these patients,
because other than the lung, all their other organs are mostly healthy,
young, and functioning normally. All they need is effective, appropriate
treatment to eradicate the eminently curable disease afflicting their
lungs, and, when they recover, they are as good as new.
Accurate diagnosis
So why are more people dying of the disease than ever before? To cure
a disease, one first has to diagnose it, and herein lies the first
stumbling block. X-rays are relatively useless in the accurate diagnosis
of tuberculosis, because many other diseases (lung cancer, sarcoidosis,
fungal diseases, viral pneumonias, bacterial pneumonias, industrial lung
diseases) can mimic tuberculosis almost exactly on the chest x-ray. A
doctor may treat lung cancer as tuberculosis (this happens with alarming
frequency, in this country and other countries) or vice versa.
Tuberculosis may be suspected on the chest x-ray, but not confirmed.
Confirmation is by demonstrating the causative organism, myco
tuberculosis, in the patient's sputum, other body fluids, or biopsy
specimens, which confirms the diagnosis with nearly 100 percent
accuracy. Other, more sophisticated and expensive investigations, like
PCR (Polymerase Chain Reaction) and gamma interferon tests do exist, but
they are reserved for doubtful cases and are irrelevant in the
day-to-day detection and diagnosis of the tuberculosis disease. Actual
demonstration of the bacillus in the patient remains the mainstay and
gold standard of diagnosis, and the most reliable.
Demonstrating the bacillus in the patient's sputum is the foundation
of diagnosis, treatment and control of tuberculosis. If the organism is
shown to be present in the patient's sputum or other secretions, the
diagnosis is confirmed. It is also the patients excreting the bacillus
in their sputum (smear positive patients) who are the most infectious.
Not all patients with pulmonary (lung) tuberculosis are infectious,
only those excreting the organism in their sputum. Patients with
tuberculosis of other organs are almost never infectious. Therefore,
infectious patients can be detected and diagnosed with certainly by
examining their sputum under the microscope. As luck would have it, the
investigation is so simple that it can be done in the most primitive of
hospitals, clinics, dispensaries, huts or even under a tree. All it
requires is the patient, a sample of correctly collected sputum, a few
simple, inexpensive stains, a microscope and an experienced, dedicated
microscopist. This is how pulmonary tuberculosis is diagnosed, treated
and controlled in resource poor countries, like those in sub - Saharan
Africa, with remarkable success. X-rays and other more sophisticated
investigations are redundant and irrelevant.
Regular treatment
Probably the greatest advantage in demonstrating the presence of the
bacillus in the patients sputum is that we know who is infectious and
who is not. Priority is given to detection of patients with infectious
forms of pulmonary tuberculosis - one infectious patient (ie; a patient
excreting the bacilli in his sputum) can infect 15-20 healthy,
uninfected people during the course of an year, if not detected and
treated. So, more the number of infectious patients detected (by sputum
examination), effectively treated and cured, lesser the number of
healthy people infected and lesser the number of new cases of
tuberculosis.
This is the basic foundation of tuberculosis control. In almost all
infectious diseases, the theme is, 'prevention is better than cure'. In
the case of tuberculosis however, cure (with adequate treatment) is
prevention - more the number of infectious cases detected and treated
adequately with high quality medication until they are cured, lesser the
number of healthy people infected. High quality, regular treatment
renders the infectious patient non-infectious remarkably quickly, within
the space of a few weeks.
Treatment of Tuberculosis is relatively lengthy, and entails the use
of a combination of antibiotics to prevent the emergence of drug
resistance. It is essential that the patient takes the correct
combination of drugs for the prescribed period, never skipping a single
dose. Herein lies the crunch-patients almost never do that, because they
forget (they are human, after all). Present day anti tuberculosis
medication is so effective that even very ill, moribund patients begin
to feel well within a few weeks.
When they feel well, they forget to adhere to their treatment
regimen. It has been demonstrated repeatedly that doling out drugs for
patients to take home is one of the least efficient ways of treating
tuberculosis.
So emerged Directly Observed Treatment Short Course (DOTS), where the
patient is actually observed to be swallowing his medication by a health
worker, on a daily basis. This mode of treatment has dramatically
improved cure rates, and dramatically reduced the emergence of the
dreaded, almost incurable, Multidrug Resistant Tuberculosis (MDRTB).
Health workers
For DOTS to be effective, all drugs should be free of charge, the
patient should not have to travel far to the health institution for his
daily treatment, there should be minimal delay in administering
treatment, the health staff should be courteous and helpful, and all
drugs should be freely available. These are difficult conditions to
fulfill in resource poor countries, but countries like Zambia and other
Sub-Saharan African countries (some of the poorest countries in the
world) have demonstrated remarkable success with this mode of treatment,
with dedicated, well trained health workers and enthusiastic
governments.
Tuberculosis does not require doctors for its treatment and
prevention. All it needs are well trained dedicated health workers who
have been taught the basic principles of treatment of the disease and
the basic mechanism of emergence of drug resistance. The health workers
may be nurses, public health midwives or well trained volunteers.
In many cases, these categories have proven to be better than doctors
in the management of the disease. Doctors sometimes tend to be
impatient, irritable or possess the I - know - it - all complex. A
health worker who asks for advice when he/she is unsure is a far better
treatment administrator than an over confident but ignorant doctor.
In fact, doctors are responsible for many of the woes tuberculosis
creates, such as multidrug resistant tuberculosis. This distressing
phenomenon starts in medical school, where medical students are
inadequately and/or inaccurately taught the basic principles of
tuberculosis diagnosis, treatment and control, and they carry this
burden of ignorance with them for the rest of their careers.
As doctors, they may treat anything they cannot diagnose as
tuberculosis (a convenient escape diagnosis), or they may treat
tuberculosis itself with the wrong combination of drugs, wrong dosage of
drugs, wrong type of drugs for the wrong period of time, or fail to
detect life threatening adverse affects of the treatment (such as
hepatitis), or create multidrug resistant tuberculosis (MDRTB), a
virtual death sentence, because patients with multidrug resistant
tuberculosis are virtually resistant to all (or almost all) first line
anti-tuberculosis drugs.
Can tuberculosis be totally eradicated, like smallpox? Probably not,
as history dating back to the origin of mankind has demonstrated. But
certainly, it can be controlled, with better living conditions,
nutrition and socio-economic parameters, efficient detection of
infectious cases and adequately treating them until cure is achieved.
This is how industrialized countries controlled the disease in the 20th
century and there is no reason why other countries cannot, in the 21st
century. |