Chain of infection 1 Prof. Hamed Adetunji

Course Overview At the end of this lecture and the activities that follow, student will be able to: List the chain of infection Describe the 6 chains correctly Develop the skills how each of the chains can be broken Apply appropriate method of braking the chain

What is infection? An illness caused by the spread of micro-organisms (bacteria, viruses, fungi or parasites) to humans from other humans, animals or the environment

Terminologies used for infectious organisms There are many terms used to describe infectious organisms. These include: ‘Bugs’ Germs Bacteria Viruses Pathogens Micro-organisms Fungi Parasites

Chain of Infection Certain conditions must be met in order for a microbe or infectious disease to be spread from person to person. This process is called the chain of infection It can only occur when all six links in the chain are intact. By breaking this chain at any of the links, the spread of infection is stopped.

The Chain of Infection The chain comprises of six sequential stages. If any of the links in the chain are missing then an infectious disease is unlikely to be transmitted to a new person. Infection prevention and control protocols are developed from this basic concept. By identifying the components that make up the chain of infection for a specific infection, then by breaking one or more of these links, transmission of the infection is stopped. The components of the chain will vary depending on the microbe and the disease it causes. It is used by epidemiologists and clinical microbiologists to develop strategies to prevent and control national epidemics such as pandemic flu.

Chain of Infection Source Method of transmission Susceptible host Exit point Entry point Microorganism

How is infection spread? Infection is spread by a chain of events. A chain of infection involves having the following parts: 1.Cause 2. Source 3. Exit 4. Method of transmission 5. Entry 6. Susceptible host

How is infection spread? Continued… 1. Cause – having micro-organisms present 2. Source * Sick people, people who have been exposed to an infectious agent, but not infected Food Equipment Water 3. Exit body fluids skin contact Droplets excretions and secretions

How is infection spread? Continued… 4. Method of Transmission – Direct contact -from one person to another Indirect contact - * from surfaces ingestion of contaminated food or water through the air as an airborne particle via an animal or insect

How is infection spread? Continued… 5. Entry - cuts or breaks in the skin Particles entering a normally sterile cavity e.g.: a catheter breaks in the mucous membrane the gastro intestinal tract respiratory tract

How is infection spread? Continued… 6. Susceptible host – elderly Immobile Very ill eg: cancer, diabetes or other chronic disease using immunosuppressant treatments Anyone who has a combination of the above

How is infection transmitted? There are 4 main ways that infection can be transmitted: Direct/Indirect contact (person to person or via third person/environment) Airborne (fine spray is coughed in the air, travel more than 1 metre) / Droplet (large respiratory droplets, less than 1 metre) Vehicle – (food/water etc.) Vector (living animals/insects)

Standard Precautions are defined as the basic work practices required to provide a minimum level of infection control. They are recommended for the treatment and care of all clients regardless of the clients’ diagnosis or presumed infectious status. Why would this be so?? Activity Question.

Standard Precautions. Continued… Work practices that are used in all circumstances to achieve a basic level of infection control They are aimed at reducing the spread of infections They apply to all clients regardless of known infectious status They are aimed to protect the Health Care Worker as well as the client.

Standard Precautions. Continued… Used for all clients, regardless of infectious status Used when risk of exposure to blood or body fluids Blood (including dried blood) All other body fluids, secretions & excretions Open wounds/broken skin Mucous membranes

Standard Precautions. Continued… Apply to – Hand hygiene Personal protective equipment (PPE) Immunisation Aseptic technique for wound care Safe handling of sharps

Standard Precautions. Continued… HAND HYGIENE Is the most important precaution to prevent the transmission of infection

Additional Precautions Are used in ADDITION to Standard Precautions. They are used when Standard Precautions are not enough to prevent transmission of organisms. They are work practices that interrupt the spread of a known infection e.g.: gastroenteritis

Additional Precautions. Continued… Address the different ways in which organisms are transmitted: Airborne Droplet Direct / Indirect Contact

Risk Management Look after your own safety Do not place others at risk. You must report & document any outbreaks or suspicions of outbreak Use PPE and clothing Comply with policies, procedures, instructions, practices and legislative requirements of the organisation

Privacy & Confidentiality Principles guide the: Collection Use & disclosure – only disclose necessary & relevant info. Storage & quality Transfer of personal information

Conclusion Remember privacy and confidentiality Legislation Policies and Procedures Personal protective equipment HAND HYGIENE

Source People, Food, Equipment, Water Method of transmission Airborne, direct contact, ingestion, surfaces – objects, benches Susceptible host Aged, immobile, immuno- suppresant Exit point Body fluid, skin, droplets Entry point Broken skin, wounds, respiratory, urinary tracts Micro-organism Bacteria Fungi Viruses Hand washing, sterilizing, disinfecting, cleaning, immunisation PPE, Hand washing waste disposal control body fluid Food handling, sterilization, airflow control, hand washing Wound care, catheter care, hand washing Recognise high risk patients, treat diseases, Identify micro- organisms BREAKING THE CHAIN OF INFECTION

Conclusion Principles of infection control apply in all settings Standard Precautions should be applied to all work practices Additional precautions apply when preventing the transmission of known infections