The Chain of Infection

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The Chain of Infection: An Overview and Prevention Strategies

This guide explains the 'chain of infection' for infectious diseases and highlights the importance of breaking this chain to prevent the spread of infections.

1. Causative Agent

The first link in the infection chain:

  • Pathogens like bacteria and viruses that cause diseases.

2. Reservoir or Source

Where pathogens live and multiply:

  • In or on people and animals.
  • Environmental reservoirs like water or soil.

3. Means of Exit

How pathogens leave the source:

  • Through saliva or mucus via coughing or sneezing.
  • Broken skin, mucous membranes, stomach, intestines, and anus.

4. Mode of Transmission

How pathogens are passed from one person to another:

  • Direct contact (hands) or indirect contact (equipment).
  • Airborne transmission (influenza, chickenpox).

5. Portal of Entry

The way pathogens enter a new host:

  • Contact with broken skin, inhalation, ingestion, or through mucous membranes.
  • Insertion of medical devices like needles or catheters.

6. Person at Risk

The final link in the chain:

  • Individuals who may become infected, depending on health and immune system strength.

Breaking the Chain of Infection

Preventing infection involves:

  • Adopting standard precautions in every situation.
  • Implementing good hand hygiene, waste disposal, laundry management, and PPE use.

It's crucial to work in ways that prevent infection, bearing in mind that carriers of micro-organisms may not show symptoms.