WHAT IS TUBERCULOSIS?
Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis (tubercle bacillus). Contrary to the belief that TB is a disease of past decades, its prevalence is increasing in many parts of the world. According to the World Health Organization (WHO, 2024), an estimated 10.6 million people fell ill with TB in 2022, and 1.3 million deaths occurred, making it one of the leading infectious disease killers globally.
FACTORS RESPONSIBLE FOR INCREASED NUMBERS OF TB CASES IN THE WORLD
To begin with, in developing countries, TB remains a life-threatening disease due to poor hygienic conditions, malnutrition, and dense populations where people live in close contact.
Moreover, immunocompromised patients, especially those with HIV/AIDS, are more susceptible. In fact, people with HIV are 16–18 times more likely to develop active TB compared to the general population (CDC, 2023).
In addition, the emergence of drug-resistant TB strains (MDR-TB and XDR-TB) has significantly contributed to TB’s persistence. WHO estimates that about 410,000 people developed MDR-TB in 2022, posing a major global health threat.
Thus, TB continues to thrive where health systems are weak, poverty is widespread, and access to timely diagnosis and treatment is limited.
WHAT IS MYCOBACTERIUM BACILLUS?
Now moving to the causative organism, Mycobacterium tuberculosis is a gram-positive, non-motile, non-spore-forming, rod-shaped, and highly aerobic bacterium. Because of its oxygen requirement, it primarily targets the lungs. However, it can infect any body organ, especially those with high oxygen supply.
Furthermore, its cell wall contains mycolic acid, a waxy substance that protects the bacteria from destruction and plays a major role in drug resistance and immune evasion. Its slow replication rate (every 18–24 hours) also makes treatment challenging, as prolonged antibiotic therapy is required.
ROUTE OF INFECTION
When it comes to transmission, TB spreads through airborne droplets released when an infected person coughs, sneezes, or talks. Inhaled droplets containing live bacilli can settle in the lungs.
Here, the immune system plays a crucial role. If the body’s defenses overpower the bacilli, the infection remains dormant (latent TB). However, if immunity is weak, the bacilli begin multiplying, leading to active TB disease.
PATHOGENESIS OF TUBERCULOSIS
The pathogenesis involves the following steps:
1. Entry of bacilli into the lungs, followed by ingestion by macrophages.
2. Formation of a tubercle a walled off lesion by immune cells to contain the bacteria.
As a result, this protective process often prevents spread, leading to latent tuberculosis. But failure of this containment leads to active tuberculosis.
WHAT IS LATENT TUBERCULOSIS?
In latent TB, the patient shows no symptoms and cannot transmit the disease. According to the CDC (2023), about one-fourth of the world’s population is infected with latent TB. Only 5–10% of these individuals will progress to active TB during their lifetime, usually when immunity weakens.
WHAT IS ACTIVE TUBERCULOSIS?
On the other hand, in active TB, bacilli overcome the immune system. Symptoms include chronic cough, hemoptysis (coughing up blood), fever, night sweats, and weight loss. At this stage, the patient is infectious.
According to WHO, over 6 million people were newly diagnosed with active TB in 2022, yet many cases remain undiagnosed due to lack of access to healthcare.
HOW DOES MYCOBACTERIUM BACILLUS SPREAD TO OTHER PARTS OF THE BODY
Once in the lungs, bacilli can spread through blood or lymphatic circulation. Consequently, they may infect organs such as the bones, brain, kidneys, liver, or reproductive system. This explains the wide range of extrapulmonary TB cases.
HOW CAN OCCURRENCE OF CNS TUBERCULOSIS BE PREVENTED?
CNS tuberculosis, such as tuberculous meningitis, is highly fatal if untreated. However, early diagnosis and treatment of pulmonary TB can prevent CNS involvement. In addition, evidence shows that BCG vaccination in infants provides up to 80% protection against severe childhood TB forms, including meningitis (WHO, 2022).
TYPES OF TUBERCULOSIS
Besides latent and active TB, several forms exist.
• Pulmonary Tuberculosis – affecting lungs (most common).
• Pleural TB – fluid accumulation in pleural space.
• Extrapulmonary Tuberculosis, such as:
• Miliary TB (disseminated, rare but fatal).
• Tuberculous Pericarditis.
• Skeletal TB (bones and joints).
• Pott’s Disease (spinal TB).
• Gastrointestinal TB.
• Hepatic TB.
• Genitourinary TB.
• CNS TB (meningitis, tuberculoma, abscess, hydrocephalus).
WHAT IS THE BCG VACCINE AND ITS EFFICACY AGAINST TB?
Turning to prevention, the BCG vaccine, derived from Mycobacterium bovis, has been in use for nearly a century.
It is particularly effective in protecting infants and young children from severe TB forms (especially meningitis and disseminated TB).
However, it is less effective in adults against pulmonary TB.
According to a Lancet meta-analysis (2014), BCG efficacy ranges from 0% to 80%, depending on geographical and environmental factors.
Nevertheless, despite its limitations, BCG remains essential in high-burden countries and is included in most national immunization programs.
TREATMENT OF TUBERCULOSIS
Treatment depends on the type of TB infection.
• Latent TB: Isoniazid (INH) for 6–9 months, or rifampin-based shorter regimens.
• Active TB: A 4-drug regimen (INH, rifampin, pyrazinamide, ethambutol) for at least 6 months, as recommended by WHO and CDC.
• Drug-resistant TB: Requires newer and stronger drugs such as bedaquiline, linezolid, delamanid, or fluoroquinolones. WHO has also endorsed shorter MDR-TB regimens (9–12 months) to improve compliance.
Even so, the biggest challenge remains patient non-adherence, which contributes to drug resistance. Here, pharmacists play a key role by counseling patients, monitoring side effects, and ensuring treatment completion.
CONCLUSION
In conclusion, tuberculosis is far from being a disease of the past. Rising drug resistance, HIV co-infection, poor treatment adherence, and lack of an effective adult vaccine are fueling its persistence. With one-quarter of the global population carrying latent TB, the risk of future outbreaks remains significant.
Therefore, global efforts involving early detection, treatment adherence, vaccination, and development of new drugs and vaccines are crucial to reduce TB burden. Pharmacists, with their expertise in pharmacotherapy and patient education, remain an essential part of TB control strategies.
FAQS ON TUBERCULOSIS
1. Is tuberculosis still common today?
Yes. TB is still one of the top infectious disease killers worldwide. According to WHO, over 10 million people develop TB every year.
2. Can TB spread by sharing utensils or shaking hands?
No. TB only spreads through the air when a person with active TB coughs, sneezes, or talks. It does not spread by sharing food, water, or touching.
3. What is the difference between latent and active TB?
Latent TB means the bacteria are present but inactive, and the person has no symptoms and is not contagious. Active TB means the bacteria are multiplying, symptoms are present, and the person can spread the disease.
4. How long does TB treatment take?
Active TB usually requires at least 6 months of multiple antibiotics. Drug-resistant TB may take 9–12 months or longer. Latent TB treatment can be shorter, depending on the regimen.
5. Can TB be completely cured?
Yes. TB is curable if treatment is taken properly and completed as prescribed. Stopping treatment early increases the risk of drug resistance.
DISCLAIMER
This article is for educational purposes only. It does not replace professional medical advice. If you suspect you have tuberculosis or are experiencing symptoms such as chronic cough, fever, night sweats, or unexplained weight loss, please consult a qualified healthcare professional immediately.
CALL TO ACTION
Tuberculosis remains a global health challenge, but awareness and timely treatment can save lives. Share this article to spread knowledge about TB prevention and treatment. Together, we can break the stigma and move closer to a TB-free world.
REFERENCES
1. World Health Organization (WHO). Global Tuberculosis Report 2023–2024.
2. Centers for Disease Control and Prevention (CDC). Tuberculosis Data and Statistics, 2023.
3. WHO. BCG Vaccine: Evidence and Impact on Childhood TB. 2022.
4. Abubakar I, et al. “The Effect of BCG Vaccination on Tuberculosis Incidence in Adults.” The Lancet, 2014. 5. World Health Organization. Drug-Resistant Tuberculosis Treatment Guidelines. 2022.