Understanding Tuberculosis: Transmission and Treatment

Aug 12, 2024

Lecture on Tuberculosis (TB)

Overview

  • Tuberculosis (TB) is an infectious disease caused by bacteria.
  • There are two types of bacteria that cause TB:
    • Mycobacterium tuberculosis
    • Mycobacterium bovis
  • TB primarily affects the lungs but can also affect other organs like the liver and bones.

Characteristics of Bacteria

  • Bacteria are prokaryotes with 70s ribosomes, circular DNA, and a peptidoglycan cell wall.

Transmission

  • Mycobacterium tuberculosis:
    • Spread through airborne droplets when an infected person coughs, speaks, or exhales.
    • Airborne droplets are inhaled by an uninfected person.
  • Mycobacterium bovis:
    • Spread through consumption of infected milk or meat from cattle.

Symptoms of TB

  • Lung-related symptoms:
    • Shortness of breath
    • Chest pain
    • Chronic cough
  • General symptoms:
    • Fever
    • Weight loss (historically known as "consumption")

Latent TB

  • The pathogen is dormant or inactive.
  • Approximately 30% of the population has latent TB.
  • Latent TB can become active in malnourished individuals, smokers, diabetics, or those with weakened immune systems (e.g., HIV patients).
  • Latent TB does not cause symptoms or spread to others.

Treatment

  • Treated with antibiotics, e.g., pyrazinamide, ethambutol, rifampicin, isoniazid, streptomycin.
  • Multiple antibiotics are given daily for 6 to 9 months.
  • Direct Observation Treatment Short-course (DOTS) ensures patients take their medication consistently.

Prevention

  • Quarantine infectious individuals during the initial 2-4 weeks.
  • Contact tracing to identify and test close contacts.
  • Vaccination with the BCG vaccine (60-70% effective).
  • Pasteurization of milk to kill Mycobacterium bovis.
  • Improve nutrition to prevent latent TB from becoming active.
  • Improve housing conditions to prevent overcrowding and poor hygiene.
  • ART medications for HIV patients to protect their immune system.

Challenges in Eradicating TB

  • TB spreads easily through the air.
  • Malnourished and poor populations are more prone to active TB.
  • Rise in HIV cases contributes to increased TB incidence.
  • Increased migration due to work, travel, or conflict facilitates TB spread.
  • Pathogens developing antibiotic resistance make treatment difficult.

TB continues to be a significant public health challenge due to its ease of transmission and evolving drug resistance. Effective management requires comprehensive treatment plans, preventive measures, and addressing social determinants of health.