Tuberculosis: The White Plague That Never Left

What is Tuberculosis?

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, a slow-growing bacterium that primarily attacks the lungs but can affect any organ. TB spreads through the air when people with active pulmonary TB cough, sneeze, or speak, releasing infectious droplets.

Most people infected with TB don't become sick immediately. The bacteria can remain dormant for years in a state called latent TB infection (LTBI). About 5-10% of those with latent infection will eventually develop active disease, usually when the immune system is weakened.

The White Plague

TB was called "consumption" because it seemed to consume patients from within, and the "white plague" for the pale appearance of sufferers. In 19th century Europe and America, TB was the leading cause of death, killing one in four people. It was romanticized in literature and opera. Many famous artists, writers, and musicians died young from TB.

The causative bacterium was identified by Robert Koch in 1882, a discovery that earned him the 1905 Nobel Prize.[5] Koch's postulates, the criteria for establishing a microbe as the cause of a disease, emerged from this work.

Clinical Presentation

Active pulmonary TB causes:

• Persistent cough (often with blood-tinged sputum)
• Fever and night sweats
• Weight loss (hence "consumption")
• Fatigue and malaise
• Chest pain

The disease progresses slowly over months, causing lung destruction if untreated. Extrapulmonary TB can present in many ways depending on the organs affected: TB meningitis, spinal TB (Pott's disease), lymph node TB, and more.

Global Burden

TB remains a global emergency:

• 10.6 million people fell ill with TB in 2021[1]
• 1.6 million died, making TB the world's second deadliest infectious disease
• About 1/4 of the world's population has latent TB infection
• Two-thirds of cases occur in 8 countries: India, Indonesia, China, Philippines, Pakistan, Nigeria, Bangladesh, and South Africa

TB is closely linked to poverty, overcrowding, malnutrition, and HIV. People living with HIV are 18 times more likely to develop active TB.

Drug-Resistant TB

One of the greatest threats is the emergence of drug-resistant TB:

Drug-resistant TB requires longer, more toxic, and more expensive treatment. Cure rates are lower, and mortality higher. In 2021, about 450,000 people developed drug-resistant TB.[4]

Diagnosis

Diagnosing TB remains challenging in resource-limited settings:

• Microscopy: Examining sputum for acid-fast bacilli (quick but insensitive)
• Culture: Gold standard but takes weeks (TB grows slowly)
• GeneXpert: Molecular test detecting TB and rifampicin resistance in 2 hours
• Chest X-ray: Shows characteristic lung abnormalities
• Tuberculin skin test/IGRA: Detects latent infection, not active disease

Treatment

Drug-susceptible TB is curable with a 6-month regimen of four antibiotics: isoniazid, rifampicin, pyrazinamide, and ethambutol.[2] This regimen has been the standard since the 1980s.

The challenge is adherence. Six months of daily pills is difficult, and incomplete treatment breeds resistance. Directly Observed Therapy (DOT), watching patients take each dose, improves outcomes but is resource-intensive.

Treatment for drug-resistant TB is far more difficult: 18-24 months of toxic drugs with significant side effects and lower cure rates. New drugs like bedaquiline and delamanid offer hope, and shorter regimens are being tested.

Prevention

The BCG vaccine, developed in 1921, provides protection against severe childhood TB but doesn't prevent adult pulmonary TB. A more effective vaccine is desperately needed, and several candidates are in clinical trials.

Other prevention strategies include:

• Treating latent TB to prevent activation
• Contact tracing and screening
• Infection control in healthcare settings
• Addressing social determinants (poverty, malnutrition, overcrowding)

"TB is an ancient disease that we should have beaten by now. We have the tools; what we lack is the will and the resources."

Why Can't We End TB?

Despite being curable since the 1950s, TB persists because:

• Funding for TB research and programs is inadequate
• The long treatment regimen makes adherence difficult
• Drug resistance is growing
• The BCG vaccine doesn't prevent adult disease
• TB disproportionately affects marginalized populations
• The slow-growing bacterium makes drug development challenging

The WHO has set a goal of ending TB by 2035. Achieving this will require new vaccines, better diagnostics, shorter treatments, and massive investment in health systems.