1. SECTION 2 NY State Infection Control Program
The Chain of Infection
SECTION 2
NY State Infection Control Program
Developed 4/08

2. Definition
The Concept of “The Chain of Infection” means that there are key principles, or specific links of a chain which must exist in order for an infection to spread. If any one of these links are broken, an infection can be halted.

3. Mechanisms of Introduction
The Chain of Infection
Natural Factors
Immune system
Foreign body or invasive device
Causative agent
Animate
Inanimate
Susceptible host
Reservoir
Entry sites
Mucous membranes
Non-intact skin
Gastrointestinal
Respiratory
Genitourinary tract
Bacteria
Virus
Fungi
Parasites
Portal of exit
Portal of entry
Drainage
Coughing
Sneezing
Secretions
Lesions
Diarrhea
Mode of
transmission
Mechanisms of Introduction
Percutaneous injury
Vascular access & invasive devices
Surgical incisions
Direct contact
Indirect contact
Droplet spread
Airborne
Common vehicle
Vector-borne