Sunday Times 2
The scourge of tuberculosis and its impact on people
In the case of tuberculosis, “Cure is prevention”. One smear positive patient, if left untreated, can infect 10-15 healthy people in the course of one year, and 10% of those newly infected people will develop tuberculosis during their lifetime.
Countless famous personalities have suffered from tuberculosis at some point in their lives. Nelson Mandela, Bishop Desmond Tutu, Tina Turner, Ringo Starr and Cat Stevens suffered from the disease during their life time. Emily Jane Bronte (Author-Wuthering Heights)and her sisters Charlotte and Anne, Jane Austen(Author, Pride & Prejudice), John Keats (Romantic Poet), D.H. Lawrence (Author),George Orwell (Author), Rene Laennec (Inventor of the Stethoscope),Eleanor Roosevelt (Wife of Theodore Roosevelt,26th President of the United States), Franz. F. Chopin (Pianist),Vivian Leigh (American actress),Franz Kafka (Novelist), Ho Chi Minh(Prime Minister/President of Vietnam), Mohammed Ali Jinnah (First Prime Minister of Pakistan) and Anton Chekov (Playwright) all died from Tuberculosis. The Hunchback of Notre Dame by Victor Hugo, though a fictional character, probably had Pott’s disease (Tuberculosis) of the spine.
Worldwide, about 10,000,000 people developed tuberculous disease in 2020, and 1.5 million died from the disease (far lower than in the 1990s, when some 3,000,000 people died of the disease every year), making tuberculosis the second biggest infectious killer in the world, after Covid-19, and the 13th leading cause of death worldwide. Each year, about USD 13 billion is needed for the diagnosis, treatment and prevention of tuberculosis worldwide.
Hearteningly, the number of new cases per 100,000 population has shown cumulative reduction of 11 percent worldwide between 2015 and 2020. An estimated 66 million lives were saved between 2015 and 2020 through the impact of accurate diagnosis and supervised treatment (Directly Observed Treatment, Short Course-DOTS) worldwide.
Sri Lanka
Sri Lanka is ideally suited for the accurate diagnosis and treatment of tuberculosis. Each district has a chest clinic equipped with X-ray, microscopic and molecular diagnostic facilities. Diagnosis, treatment and contact tracing are entirely free of charge. Additionally, in Sri Lanka, a health institution exists within 4km of every person’s home, making it relatively easy for patients to receive treatment.
In 2020, Sri Lanka showed an incidence rate (number of new cases per 100,000 population) of 32.2/100,000, whereas the estimated incidence (estimated by the WHO) was 64/100,000, which translates into 3000-4000 undiagnosed TB cases.
Many patients seek treatment late in the course of the disease, possibly due to fear of stigmatisation, taking alternative forms of treatment, ignorance of early symptoms of the disease and, most recently, the fear engendered by the Covid-19 pandemic. By the time these patients reach the chest clinic, they would have infected most members of their household. Almost 100% of sputum smear positive (highly infectious patients excreting large numbers of tuberculosis bacilli in their sputum) patients die within 2 years, if left untreated, and infect 10-15 healthy people in the course of one year, if left undiagnosed.
Why is its eradication so urgent?
Tuberculosis, poverty and the world economy are inextricably linked. Tuberculosis predominantly affects the productive segments of the population (the 15 to 54 year age group), and, if many in this age group either fall sick or succumb to the disease, the poverty index rises and the economy of the country suffers. This is perfectly illustrated by some Sub-Saharan African countries, whose economies have been decimated by the twin HIV/Tuberculosis epidemic, and this was BEFORE the Covid-19 pandemic.
What makes TB so tenacious
and difficult to eradicate?
Simply, the ability of the causative organism (Mycobacterium tuberculosis, a bacterium) to survive under the most unfavourable of conditions (it can survive for months on end, suspended in mid-air, in dark, unventilated rooms) or in any organ of the human body, lying dormant for years on end, not causing any disease symptoms, and, when conditions are favourable, (predominantly compromise of the immune system in the host, due to such conditions as severe malnutrition, alcoholism, HIV infection, diabetes, excessive tobacco smoking), the hibernating tuberculosis germ wakes up, starts multiplying and slowly starts destroying the organ that is hosting it (the lung in 90% of cases, or the kidneys, bone, meninges and the brain, the skin — in fact any organ in the human body – in 10% of cases).
Its tenacity and will to survive is such that it is able to survive unhurt inside the cytoplasm of the Macrophage, a powerful front-line soldier cell of the immune system, the very cell specifically designed to swallow and destroy organisms such as Myco.tuberculosis. Specific drugs are necessary to eradicate the TB bacillus inside these Macrophages. Undeterred, the TB bacillus will start multiplying inside the host Macrophage, kill it and emerge triumphant, on its way to cause clinical disease in a new patient or a relapse in an already treated and supposedly cured patient. The extraordinary ability of the organism to survive the full firepower of the human immune system is unparalleled. Another reasoning for why this disease may thrive amongst us is due to human factors such as poor health seeking behaviour, fear of stigmatisation and poor compliance to prolong periods of treatment.
How is TB transmitted?
Tuberculosis is Covid-19 in slow motion. Both diseases are transmitted in similar ways. Both are transmitted in tiny droplets of sputum, when a patient suffering from tuberculosis or Covid -19 coughs, sneezes, speaks or laughs. These droplets are inhaled (breathed in) by victims, reach their lungs and the virus or TB bacillus starts multiplying. One notable exception is that, it is virtually impossible to become infected by contaminated hands or food coming in contact with the nose or mouth, in the case of tuberculosis (in contrast to Covid-19) , unless the number of contaminating tuberculosis bacilli is very large.
Diagnosis
The gold standard for a positive diagnosis of tuberculosis was the actual, microscopically visible demonstration of the causative organism, Myco.tuberculosis, in a specimen (sputum, urine, cerebrospinal fluid, pleural fluid and biopsy specimens) obtained from the patient, by staining or culture. But now, Rapid Molecular tests (Xpert MTB/RIF Ultra and Truenat assays) which are sensitive and accurate, are recommended by the World Health Organisation, for early, accurate diagnosis of tuberculosis and the detection of drug resistant tuberculosis.
Prevention
Why not vaccinate everyone (or almost everyone) against tuberculosis and be done with it, like in the case of Covid-19? Unfortunately, things don’t work that way. Some 1.9 billion people are already infected by Mycobacterium tuberculosis, and their activated immune systems would destroy the administered vaccine almost immediately, because the vaccine, BCG (Bacille Calmette Guerin) consists of attenuated (weakened) tuberculosis bacilli. BCG, however, is highly effective in preventing life threatening complications of childhood tuberculosis, like Miliary Tuberculosis and Tuberculous Meningitis, and it is a sine qua non that all children under the age of 5 years should be BCG vaccinated. The BCG vaccination programme in Sri Lanka is so efficient that BCG vaccination coverage at birth is nearly 99%. It is extremely rare to see a case of Tuberculous Meningitis or Miliary Tuberculosis in a paediatric ward at the present time. Unfortunately, BCG has no impact on reducing the incidence of adult forms of tuberculosis.
So how does one prevent transmission of tuberculosis? Here, the hackneyed cliché “Prevention is better than cure” does not hold. In the case of tuberculosis, “Cure is prevention”. One smear positive patient, if left untreated, can infect 10-15 healthy people in the course of one year, and 10% of those newly infected people will develop tuberculosis during their lifetime. So, more the number of sputum smear positive patients detected, treated adequately and permanently cured, less the number of healthy people infected, less the number of new cases of tuberculosis and the incidence of new Tuberculosis cases falls.
Treatment
Treatment of tuberculosis is with a combination of four powerful antibiotics for the first two months and two of the same antibiotics for the next four months. If the patient does not default treatment (unfortunately, this happens far too frequently and is the single most important cause for treatment failure and emergence of multidrug resistance) and the treatment is supervised by a health worker(i.e. the patient is given the daily dose of medication by the health worker and is actually observed by the latter while the patient swallows the medication, to ensure that the patient has actually taken his/her daily dose of medication), a cure rate of approximately 95% can be expected. It is essential that the patient takes the medication daily until told to stop treatment at the end of (usually) 6 months. One of the biggest pluses of modern anti-tuberculosis treatment is that an infectious patient becomes non-infectious relatively quickly (2 weeks to 1 month) and there is no longer any need for isolation of the patient.
Treatment of tuberculosis is one of the most cost-effective health interventions in the world, equivalent to Measles vaccination in children and treatment of diarrhoeal diseases with Oral Rehydration Solution (ORS), because of the numbers of productive lives saved at such minimal cost. The full course of treatment of tuberculosis costs around USD 30. In Sri Lanka the treatment is free. For that, the country gets back a relatively healthy, young to middle aged (tuberculosis affects mostly the 15-54-year age group), productive human being, able to go back to work and start contributing to the economy.
Diseases like diabetes, hypertension and cancer are mostly incurable and far more expensive to treat, and the return is minimal. Tuberculosis remains one of the few eminently curable, relatively inexpensive-to-treat diseases in a world ravaged by incurable, degenerative, expensive-to-treat, ever increasing Non-Communicable Diseases or with deadly, “sorry-no- treatment-available -”, eternally mutating, viruses.
So let’s together overcome the barriers and put our efforts for eradication of TB by 2035
(The writer is a respiratory physician. He wrote this article on behalf of the Sri Lanka College of Pulmonology)