Tuberculosis: The White Death

Introduction

• Speaker: John Green (voiceover by Steve from kurzgesagt)
• Topic: The history and impact of tuberculosis (TB), caused by Mycobacterium tuberculosis

History & Impact

• Tuberculosis, known as the White Death, has affected humanity for thousands or even millions of years.
• Significant historical milestones:
  • Present during the control of fire and cultural developments.
  • Caused 1 in 4 deaths in Britain by 1815.
  • Killed a billion people in the last 200 years.
  • Continues to be the infectious disease with the highest death toll.
• Current status: 1 in 4 humans are infected with TB bacteria.

Characteristics of TB

The Perfect Human Predator

• Infection Method: Enters through airways and lodges in the lungs.
• Immune Evasion: Infects macrophages, immune system cells, and resists destruction by developing a thick, waxy coat.
• Replication: TB bacteria replicate slowly, allowing it to evade immune response for a long time.
• Granuloma Formation: Infected macrophages are contained in granulomas, protecting TB bacteria and allowing them to remain dormant for years.

Active vs. Latent TB

• Latent TB: Dormant infection, contained in granulomas, no symptoms, bacteria inactive.
• Active TB: Occurs when the immune system can't contain the infection anymore; granulomas burst, causing symptoms.
  • Symptoms: Difficulty breathing, coughing (sometimes with blood), high fever, weight loss.
  • Transmission: Spreads via tiny droplets from an infected person's cough.

Global Impact

• Infection Spread: Especially common in crowded, poorly ventilated spaces.
• Historical Outbreaks: Exploded during the Industrial Revolution.
• Current Hotspots: 2022—Most cases in India, China, Indonesia, Philippines, Pakistan, and Nigeria.
• Mortality: 1.3 million deaths in 2023 alone.
• Infection Rate: An active TB patient infects 5-15 people per year.

Treatment & Challenges

• Antibiotics: TB can be cured with a four-month regimen of four different antibiotics.
• Historical Context: Drugs developed between 1940-1965; distribution was poor, leaving TB active in many parts of the world.
• Drug Resistance: Mismanagement and lack of aggressive action has led to antibiotic-resistant strains.
• Vaccine: Over 100 years old and not very effective.

Future Outlook

• New Developments: Since 2012, two new classes of drugs, better vaccines on the horizon, quick tests developed by companies that made Covid tests.
• Opportunity for Eradication: Raising awareness and supporting clinical trials and care delivery.
• Action Needed: Increased global effort to fight TB and eradicate it.
• Organizations: Partners in Health (pih.org) and resources like Crash Course Lecture on TB.

Conclusion

• TB has been a persistent human plague, but it's curable and preventable.
• Awareness and global action can finally push TB into history.
• Around 4,000 people die from TB every day; we have the means to stop it.
• Encourage support and learning through provided resources.