The chain of infection is made up of six links that describe how an infection spreads. These links are:
- Infectious Agent: The microorganism or pathogen that causes the disease, which may be bacteria, viruses, fungi, or parasites.
- Reservoir: The place where the microorganism lives and multiplies, including humans, animals, objects, soil, and water.
- Portal of Exit: The path through which the microorganism leaves the reservoir, such as through coughing, sneezing, bodily fluids, wounds, or other secretions.
- Mode of Transmission: The way the infectious agent is transmitted from one host to another, which can be direct contact, indirect contact via surfaces, airborne droplets, vectors like insects, or other means.
- Portal of Entry: The path by which the microorganism enters a new host, such as through broken skin, respiratory tract, mucous membranes, or medical devices.
- Susceptible Host: An individual who is vulnerable to infection due to factors like weakened immune system, age, stress, or existing health conditions.
Breaking or interrupting any of these links can prevent the transmission of infection and stop the spread of disease.
