Respiratory Infections: Whooping Cough, Tuberculosis, Influenza

Whooping Cough (Pertussis)

  • Babies:
    • Gasping for air.
    • Can turn blue (cyanosis).
    • Very tired.
  • Prevention:
    • Diphtheria, Tetanus, and Pertussis (DTaP) vaccine.
    • Tetanus, Diphtheria, and Pertussis (Tdap) vaccine.

Tuberculosis (TB)

  • Transmission:
    • Inhalation of droplets containing Mycobacterium tuberculosis.
    • Mucus membranes are common entry sites for microbes.
  • Process:
    • Inhaled droplets reach the alveoli in the lungs.
    • Alveolar macrophages ingest the M. tuberculosis bacteria.
    • Components in the cell wall of M. tuberculosis stimulate an inflammatory response, recruiting more macrophages.
    • M. tuberculosis can survive inside macrophages, hindering treatment.
    • M. tuberculosis prevents the fusion of phagosomes and lysosomes, thus avoiding destruction.
  • Tubercle Formation:
    • Macrophages wall off the infection, forming a granuloma.
    • Necrosis occurs in the center of the granuloma, forming a caseous center (resembling cheese).
  • Latent TB:
    • The microbe is contained and dormant.
    • The person is asymptomatic but can be reactivated, especially in immunocompromised individuals.
  • Alveoli:
    • Bubble-like structures in the lungs where gas exchange occurs.
    • Surrounded by blood capillaries for gas exchange.
  • Immune Response and Progression:
    • Macrophages ingest tubercle bacilli after inhalation.
    • Inflammation is triggered, leading to the reproduction of bacteria inside macrophages.
    • Macrophages move into the alveolar space.
    • Early tubercle formation occurs.
    • Macrophages die off, resulting in necrosis and the formation of a caseous center.
    • Macrophages try to contain the infection, preventing its spread into the capillaries.
    • The contained area eventually becomes calcified.
  • TB Test Results:
    • A person with contained and calcified TB would yield a positive result.
  • Symptoms:
    • Feeling unwell and experiencing inflammation.
  • Treatment Challenges:
    • The infection, once contained, is in its own "bubble", making drug delivery difficult.
  • First-line treatment:
    • Isoniazid.
    • Rifampin.
    • Ethambutol
    • Pyrazinamide.
  • Lung Fluid Buildup:
    • Fluid in the lungs reduces gas exchange.
    • This can lead to hospitalization and increased risk of nosocomial infections.

Other Infections:

  • Treated with Tetracycline.

Influenza (Flu)

  • Transmission:
    • Common in daycare settings due to close contact.
  • Treatment:
    • Antivirals: Work against viruses.
    • Must be administered within hours of suspected exposure to be effective.
  • Viral Components:
    • Hemagglutinin (HA): Allows the virus to enter the cell.
    • Neuraminidase (NA): Helps the virus to separate from the infected cell, promoting virulence.
  • Antigenic Drift vs. Shift:
    • Antigenic Drift: Minor changes in viral spikes (HA and NA), allowing the virus to evade the immune system, necessitating new vaccines.
    • Antigenic Shift: Major changes in viral spikes.
  • Vaccines:
    • The CDC predicts which virus will cause the next pandemic, guiding vaccine development.
    • Vaccines do not provide long-term immunity due to viral mutation each season.
  • Flu Season:
    • May through October.
  • Diagnosis:
    • Difficult due to similar symptoms with other respiratory infections.
  • Antiviral Treatment:
    • Inhibits the virus from entering host cells if treatment is started quickly after exposure.