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.