Choose one of the following infectious diseases: Influenza A (H1N1) virus Methicillin-resistant Staphylococcus aureus, Clostridium difficile Tuberculosis, Severe Acute Respiratory Syndrome or Hepatitis B. Describe its chain of infection., Identify vulnerable populations. Where is it endemic? Is it currently an epidemic? Pandemic? Support your position., Does herd immunity apply? What are the current treatments for this disease process?, How is public health policy mitigating this disease? What are the projections for the future?
Tuberculosis: Chain of Infection and Public Health Impact
Chain of Infection
Tuberculosis (TB) is caused by Mycobacterium tuberculosis and spreads primarily through airborne transmission. The chain of infection includes:
- Infectious Agent – Mycobacterium tuberculosis, a bacterium that primarily affects the lungs.
- Reservoir – Humans are the primary reservoir; infected individuals with active TB can transmit the disease.
- Portal of Exit – The bacteria leave the body through respiratory droplets when an infected person coughs, sneezes, or speaks.
- Mode of Transmission – TB spreads through inhalation of airborne droplets, especially in enclosed spaces.
- Portal of Entry – The bacteria enter a new host through inhalation into the respiratory tract.
- Susceptible Host – Individuals with weakened immune systems, such as those with HIV, malnutrition, or chronic illnesses, are at higher risk.
Vulnerable Populations
TB disproportionately affects:
- Individuals with compromised immune systems (HIV/AIDS patients, cancer patients, diabetics).
- People living in crowded conditions (prisons, homeless shelters, refugee camps).
- Low-income populations with limited healthcare access.
- Healthcare workers exposed to infected patients.
Endemic Regions and Current Epidemiology
TB is endemic in many low- and middle-income countries, particularly in:
- Sub-Saharan Africa
- South and Southeast Asia
- Latin America
- Eastern Europe
While TB remains a global health issue, it is not currently classified as a pandemic. However, multidrug-resistant TB (MDR-TB) has been a growing concern in recent years.
Herd Immunity and TB
Herd immunity does not apply effectively to TB because the Mycobacterium tuberculosis bacterium can remain latent in the body for years. The Bacillus Calmette-Guérin (BCG) vaccine offers some protection, especially in children, but does not prevent latent TB infection from becoming active in adults.
Current Treatments
Treatment for active TB includes:
- First-line antibiotics: Isoniazid, Rifampin, Ethambutol, and Pyrazinamide (6-9 month regimen).
- Multidrug-resistant TB (MDR-TB): Requires longer treatment with second-line drugs like Bedaquiline and Linezolid.
- Latent TB treatment: Isoniazid or Rifampin for 3-9 months to prevent progression to active TB.
Public Health Policies Mitigating TB
- Surveillance and Screening: Early detection programs in high-risk populations.
- Directly Observed Therapy (DOTS): Ensures patients complete their treatment to prevent drug resistance.
- Vaccination: BCG vaccine for newborns in high-prevalence areas.
- Global Initiatives: WHO’s End TB Strategy aims to reduce TB deaths by 90% by 203 APA