Breaking the Chain of Infection
A health care worker must understand how to prevent the spread of infection. Understanding how infections spread will protect you as a health care worker and help you to stay healthy. Because infections can be especially dangerous for older adults and people who have poor overall health, understanding the spread of infection will also help you to provide the best possible care.
Infections are caused by microbes, or microorganisms, which are too small to see without microscope. Microbes are all around us, but many of them are harmless. Microbes that cause disease are called pathogens.
Six things must happen in order for a pathogen to enter the body and cause an infection. Medical professionals call these six requirements the chain of infection. Eliminating just one of these links can prevent an infection from spreading.
The first link in the chain is the pathogen. If no pathogens are present, then an infection cannot occur.
The second link is the reservoir, or place where the microbes grow and multiply. The human body is one reservoir for microbes.
The third link is the portal of exit. This is how the microbes leave the reservoir. If the microbes are leaving a human body, for example, then the portal of exit could be through the mouth or nose or breaks in the skin. When a sick person coughs, sneezes, or bleeds, pathogens exit the body.
The fourth link is the method of transmission. This is how the microbes pass from one person to another. When a healthy person touches a sick person or breathes infected air, direct transmission of the pathogens can occur. Indirect transmission can happen when a healthy person touches something, like a dirty tissue, that has been contaminated by an infected person.
The fifth link is the portal of entry. This is how the microbes enter a new reservoir. Any body opening, including breaks in the skin, can be a portal of entry.
The sixth link is a susceptible host. This means that the pathogen must enter a person who is capable of acquiring the infection.