Overview

  • Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis bacteria.
  • Primarily affects the lungs (pulmonary TB) but can impact other organs (extrapulmonary TB).
  • Spread through airborne droplets when an infected person coughs, sneezes, or speaks.
  • TB is ancient—evidence found in Egyptian mummies—but remains a major global health challenge.

Analogies & Real-World Examples

TB as a “Stealthy Burglar”

  • Imagine TB bacteria as stealthy burglars. They sneak into the house (body), hide in closets (lungs), and sometimes remain undetected for years (latent TB).
  • Only when the immune system weakens does the burglar start causing visible damage (active TB).

Latent vs. Active TB: “Dormant Seeds”

  • Latent TB is like seeds lying dormant in the soil. They don’t grow unless the conditions are right (immune suppression).
  • Active TB is when these seeds sprout, causing visible symptoms and spreading to other “gardens” (people).

TB Transmission: “Glitter in the Air”

  • TB spreads like glitter thrown into the air. You can’t see the individual particles, but if you breathe in, some may stick to you.
  • Not everyone exposed gets sick—depends on immune system strength.

Pathophysiology

  • After inhalation, bacteria reach the alveoli in the lungs.
  • Macrophages engulf the bacteria, but TB can survive and multiply inside these cells.
  • Formation of granulomas (clusters of immune cells) to contain the infection—like building walls around the burglars.
  • If the immune system fails, bacteria break out, causing active disease.

Symptoms

  • Pulmonary TB: Persistent cough (>3 weeks), hemoptysis (coughing blood), chest pain, fever, night sweats, weight loss, fatigue.
  • Extrapulmonary TB: Symptoms depend on the organ affected (e.g., lymph nodes, bones, brain).

Diagnosis

  • Skin Test (Mantoux): Injection of TB antigens under the skin; swelling indicates exposure.
  • Blood Tests (IGRA): Measures immune response to TB proteins.
  • Chest X-ray: Detects lung abnormalities.
  • Sputum Test: Identifies TB bacteria in coughed-up mucus.

Treatment

  • Standard regimen: 6 months of antibiotics (isoniazid, rifampicin, pyrazinamide, ethambutol).
  • Directly Observed Therapy (DOT): Health workers supervise patients taking medication to ensure compliance.
  • Drug-resistant TB (MDR-TB, XDR-TB): Requires longer, more complex treatment.

Common Misconceptions

  1. “TB is a disease of the past.”

    • TB remains one of the top 10 causes of death worldwide. In 2022, 10.6 million people fell ill with TB (WHO).

  2. “Only poor countries get TB.”

    • TB can affect anyone, anywhere. Outbreaks occur in developed nations, especially among vulnerable populations.

  3. “You can’t get TB if you’re healthy.”

    • Healthy people can become infected, though their immune system may contain the bacteria (latent TB).

  4. “TB is always contagious.”

    • Only active pulmonary TB is contagious. Latent TB is not.

  5. “TB is easy to treat.”

    • Treatment is lengthy and can have side effects. Drug-resistant TB is much harder to cure.

Emerging Technologies

Rapid Diagnostics

  • GeneXpert MTB/RIF: Automated molecular test that detects TB DNA and resistance to rifampicin within 2 hours.
  • CRISPR-based Diagnostics: Uses gene-editing technology for ultra-fast and precise detection (Nature Biomedical Engineering, 2021).

Vaccines

  • M72/AS01E Vaccine: New candidate showing promising results in preventing active TB among latently infected adults (NEJM, 2019).
  • mRNA Vaccines: Inspired by COVID-19 vaccine technology, being explored for TB.

Digital Adherence Tools

  • Smartphone apps and digital pillboxes remind patients to take medication, reducing treatment dropouts.

AI in TB Detection

  • Artificial intelligence algorithms analyze chest X-rays for TB signs, speeding up diagnosis in remote areas.

Project Idea

Design a TB Awareness Campaign Using Virtual Reality (VR):

  • Create an immersive VR experience simulating the journey of TB bacteria in the human body.
  • Include interactive modules on transmission, symptoms, and treatment.
  • Target schools and community centers to educate about TB prevention and dispel misconceptions.

Most Surprising Aspect

  • TB can remain dormant in the body for decades.
    • An estimated 1.7 billion people (1/4 of the world’s population) have latent TB.
    • Only 5-10% will develop active TB in their lifetime, but this reservoir makes eradication extremely challenging.

Recent Research

Connections: Great Barrier Reef Analogy

  • Like the Great Barrier Reef—Earth’s largest living structure—TB is vast and complex, spanning continents and affecting millions.
  • Both are visible on a global scale, but their true extent and impact are often underestimated.

Key Facts & Figures

  • TB is curable and preventable, but challenges remain due to drug resistance, stigma, and healthcare access.
  • TB kills more people annually than HIV/AIDS.
  • The COVID-19 pandemic disrupted TB services, leading to increased deaths in 2021 (WHO Global TB Report).

References

  • World Health Organization. Global Tuberculosis Report 2023.
  • Nature Biomedical Engineering. CRISPR-based tuberculosis diagnosis. 2021.
  • New England Journal of Medicine. M72/AS01E Vaccine Trial. 2019.