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

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.

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