The Chain of Infection: The Chain of infection is a process involving the following steps: a) Causative agent (source) b) Reservoir c) Portal of exit d) Method of transmission e)Portal of entry f) Susceptible host g) back to source
“Causative” agent: The source, also known as a “causative” agent, is a pathogen that enters the body and causes disease, such as bacteria, fungi, viruses and protozoa.
The “reservoir”: The “reservoir” is a place, like lungs, blood, or large intestines, where a pathogen lives and thrives. It is typically a place that is warm, dark, and moist, and where there is food. Some pathogens also need Oxygen, others don’t.
“Portal of exit”: A “portal of exit” is a place from which pathogens can leave the body, such as the mouth, nose, eyes, or a cut. The “portal of entry” is an opening in an uninfected body, such as mouth, nose, eyes, a cut or very dry skin, or a mucous membrane that lines the body’s cavities, such as the mouth, nose, eyes, rectum, or genitals.
“Mode of transmission”: The “mode of transmission” is how pathogens transmit from one body to the other. This can be through the air or through direct contact such as touching the infected persons or their secretions. Indirect contact such as touching contaminated clothing is also possible.
“Susceptible host”: A “susceptible host” is an uninfected person who could become sick, such as healthcare workers as well as other clients the caregiver comes in contact with.