Infection is not random but takes a predictable course called a chain of infection. The chain of infection can be comprised of six interrelated links, which include an infectious agent, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. Preventing any of these six links can readily control the spread of infection.
The first leg of this link is the microorganism that leads to an illness, which can be in the form of bacteria, viruses, fungi, or a parasite. Examples include MRSA, influenza, norovirus, RSV, and COVID-19. They all have different severities and contagiousness but need a host to survive.
Reservoir is the environment where the infectious agent lives and breeds. The reservoir can be a human being, animals, water, soil, or even a surface in a healthcare facility. Germs may be present in a human’s blood, skin, or other body systems such as the respiratory tract or urinary tract.
In order for an infection to spread, it is necessary for it to leave its reservoir. Some of the most common ways in which this is achieved include coughing, sneezing, an open wound, and bodily fluids.
This is how the agent is transmitted. How it is spread can be through direct contact, droplets, an airborne vector, or an object. In a healthcare setting, direct contact is the most common mode of transmission, which can be through a healthcare provider’s hands if they do not practice good hand hygiene practices.
The portal of entry is the pathway which the agent travels in order to gain entry into a new host. Often, this will correspond with the portal of exit, such as respiratory droplets entering through the nose and/or mouth, or bacteria entering through compromised skin.
The final part of this process is a human being susceptible to infection. Age, stressful living, poor dietary habits, diseases, and drugs such as those used in chemotherapy affect susceptibility.
“Breaking the Chain”
To prevent an infection from happening, a link within an infection chain must be disrupted. The most effective way to prevent an infection from being transmitted is through hand washing. Nowadays, healthcare providers recommend all healthcare professionals to wash their hands frequently. Hand washing is considered the most important way to prevent an infection chain in healthcare providers because it transmits bacteria from healthcare providers.
To prevent portals of exit, people can cover their coughs and sneezes and wear a mask if needed. On the other hand, portals of entry can be protected by using PPE, practicing good wound care, and practicing good hand hygiene.
Reducing transmission can include other things, such as sterilizing medical equipment, disinfecting surfaces, and practicing social distancing. Protecting the susceptible host is also a critical part of this, such as getting vaccinations, good nutrition, and controlling existing health issues to boost immunity.
Conclusion
In conclusion, knowledge of the chain of infection is critical in controlling the spread of diseases. Through an intervention in one phase of the chain of infection—by observing hand washing, using personal protective equipment, environmental cleaning, sterilization of instruments/equipment, surface disinfection, or vaccination—we can greatly lower our chances of being infected.
