Chain of Infection

What is it?

The chain of infection is an infection or communicable disease model.

  1. Pathogen / Infection agents

  • Bacteria

  • Virus

  • Parasite

  • Fungi

  1. Reservoir

Something that holds bacteria.

Fomite: hard, inanimate, surface or object that holds bacteria.

Example for reservoirs:-

  • Humans

  • Environment

  • Rodents (aka vector)

  • Birds

  • Water

  • Equipment

  1. Portal of exit

  • Open wounds/skin

  • Splatter or body fluids

  • Aerosols (eg: Bacteria that are sprayed when you are coughing)

  1. Mode of TRANSMISSION (don’t confuse transportation!!!)

  • Transmission from host to host

  • Direct or indirect contact

  • Ingestion

  • Inhalation

  1. Portal of entry

  • Broken skin/incisions

  • Respiratory tract

  • Mucous Membranes

  • Catheters/tubes/IV

  1. Susceptible Host

  • Young (5 years or younger)

  • Elderly population

  • Immunosuppressed

  • Anyone (depends on the pathogen)

Medical Asepsis

A/sep/sis - A means without ; Sep means poison, rot or infection ; sis means condition

Helps to contain infectious organisms and to maintain an environment free from contamination.

Sterilize vs Disinfect: Sterilize is to rid of bacteria while disinfect completely is to just kill off basic bacteria.

  1. Hand washing

  2. Gowns, Masks, Gloves (PPE)

  3. Basic Hygiene

  4. Clean Linens

  5. Autoclave : Sterilization of instruments

Standard Precautions

Treating everything as it is infected. This widens the focus of protective tactics.

PREVENTION
1. Pathogen : antibiotic, antifungal, antiviral, pasteurization, chlorination (these are just examples)

2. Reservoir: isolation, surveillance, vector control (rat/pest control)

3. Portal of exit: PPE (masks, face shields), proper bandaging/wound care,

4. Mode of transmission: Sterilizing, disinfecting, PPE, hand hygiene

5. Portal of entry: PPE, first aid, hand hygiene

6. Susceptible Host: Good nutrition, treatments, immunizations, patient education