Definition: The Chain of Infection
How do viruses pass from one person to the next? When one child has a cold at school, why is the rest of the class likely to come down with one the next week? Let's explore how infection gets from one place to another, or the chain of infection.
chain of infection
The chain of infection, if we think of it as an actual chain, is made up of six different links: pathogen (infectious agent), reservoir, portal of exit, means of transmission, portal of entry, and the new host. Each link has a unique role in the chain, and each can be interrupted, or broken, through various means.
The Six Links
The first link is the pathogen itself. This is the disease-causing organism. For many illnesses and diseases this is a virus or bacterium. In order to break this link,