Overview
This lecture reviews the chain of infection and the stages of infection, focusing on key concepts relevant for nursing and infection control.
Chain of Infection
- The chain of infection describes how a pathogen moves from its source to a new host.
- Infectious agent is the specific pathogen, such as a virus or bacteria (e.g., E. coli, influenza).
- Reservoir is where the pathogen lives and multiplies, like water or living organisms.
- Portal of exit is how the pathogen leaves the reservoir (e.g., nose, mouth, blood, feces).
- Mode of transmission explains how the pathogen travels to a new host (e.g., direct contact, droplet, airborne).
- Portal of entry is how the pathogen enters the new host (e.g., nose, mouth, eyes).
- The host must be susceptible to become infected; previous disease or strong immunity reduces susceptibility.
Stages of Infection
- Incubation period is the time from exposure to symptom onset; the person may not know they are sick but could be contagious.
- Prodromal period involves vague, non-specific symptoms such as fatigue or general malaise.
- Illness phase presents specific symptoms related to the particular disease (e.g., fever, cough, diarrhea).
- Convalescence is the recovery stage, lasting from symptom improvement to full healing, which varies by disease severity.
Key Terms & Definitions
- Infectious Agent — the microorganism causing disease (e.g., bacteria, virus).
- Reservoir — the environment where the pathogen lives, grows, and multiplies.
- Portal of Exit — the path by which a pathogen leaves its reservoir.
- Mode of Transmission — how the pathogen is transferred to a new host.
- Portal of Entry — the way a pathogen enters a susceptible host.
- Host — an organism that can be infected if susceptible.
- Incubation Period — time between pathogen entry and appearance of symptoms.
- Prodromal Period — early stage with vague symptoms.
- Illness Phase — stage with specific disease symptoms.
- Convalescence — stage of gradual recovery after illness.
Action Items / Next Steps
- Review cards 32-34 in the Fundamentals of Nursing flashcard set for illustrations and details.
- Prepare to study types of immunity and illness in the next video.