Lecture Notes: Chain and Stages of Infection

Introduction

• Presented by Meris in a video session.
• Reference to Fundamentals of Nursing flashcards available at levelupRN.com.
• Focus on card numbers 32-34 for this session.

Chain of Infection

1. Infectious Agent

   • Pathogen responsible for infection (e.g., virus, bacteria).
   • Examples include E. coli, Influenza A or B.

2. Reservoir

   • The habitat where the pathogen lives and multiplies.
   • Could be water bodies, or living organisms.

3. Portal of Exit

   • The pathway for the pathogen to exit the reservoir.
   • Examples include respiratory secretions (nose/mouth), blood, feces.

4. Mode of Transmission

   • How the pathogen moves from the reservoir to a new host.
   • Methods include direct contact, droplet (respiratory), or airborne transmission.

5. Portal of Entry

   • The means by which the pathogen enters the new host.
   • Can include the respiratory tract or through the eyes (touching face).

6. Host

   • Must be susceptible for infection to occur.
   • Susceptibility varies with immunity, previous exposure, or immune system strength.

Stages of Infection

1. Incubation Period

   • Time between pathogen entry and appearance of symptoms.
   • Pathogen multiplies without symptomatic awareness.
   • Long incubation can lead to unintentional spread.

2. Prodromal Period

   • Initial vague symptoms appear.
   • Includes fatigue, weakness, and general malaise.

3. Illness Phase

   • Specific symptoms associated with the pathogen manifest.
   • Example: Influenza symptoms like fever, cough, body aches.
   • Gastroenteritis symptoms can include vomiting and diarrhea.

4. Convalescence Stage

   • Recovery phase where symptoms diminish until full health is restored.
   • Duration depends on the severity of the infection.

Conclusion

• Summary of key points from the lecture.
• Encouragement to engage with the video content through comments and likes.
• Preview of the next topic covering types of immunity and illness.
• Encourage subscription to the channel for updates.