CMA (AAMA) Exam Prep Course

About Lesson

Lesson 2.2: Modes of Infectious Transmission and Precautions

Learning Objectives

Understand the different modes of infectious transmission.
Learn the appropriate precautions to prevent the spread of infections.
Identify the importance of standard precautions and transmission-based precautions.

Introduction to Modes of Infectious Transmission

Infectious diseases can be transmitted through various modes. Understanding these modes is crucial for implementing effective infection control measures to prevent the spread of diseases.

Modes of Infectious Transmission

Several modes of infectious transmission exist, each requiring specific precautions to control and prevent the spread of infections.

Direct Contact Transmission

Direct contact transmission occurs when there is physical contact between an infected person and a susceptible person, allowing pathogens to transfer directly.

Examples: Touching, kissing, sexual contact.

Indirect Contact Transmission

Indirect contact transmission involves the transfer of pathogens from an infected person to a susceptible person via a contaminated object or surface.

Examples: Door handles, medical instruments, shared personal items.

Droplet Transmission

Droplet transmission occurs when respiratory droplets containing pathogens are expelled from an infected person and inhaled by or deposited on the mucous membranes of a susceptible person.

Examples: Coughing, sneezing, talking.

Airborne Transmission

Airborne transmission involves the spread of infectious agents through airborne particles that remain infectious over time and distance. These particles can be inhaled by susceptible individuals.

Examples: Tuberculosis, measles, chickenpox.

Vector-Borne Transmission

Vector-borne transmission occurs when infectious agents are transmitted to humans through vectors such as insects or animals.

Examples: Mosquitoes (malaria), ticks (Lyme disease).

Common Modes of Transmission Chart

Mode	Description	Examples
Direct Contact	Physical contact between infected and susceptible person	Touching, kissing, sexual contact
Indirect Contact	Transfer via contaminated objects or surfaces	Door handles, medical instruments
Droplet	Expelled respiratory droplets inhaled or deposited on mucous membranes	Coughing, sneezing, talking
Airborne	Infectious particles spread through the air and inhaled	Tuberculosis, measles
Vector-Borne	Transmission through vectors such as insects or animals	Mosquitoes (malaria), ticks (Lyme disease)

Standard Precautions

Standard precautions are the minimum infection prevention practices that apply to all patient care, regardless of the patient’s suspected or confirmed infection status.

Components of Standard Precautions

Hand Hygiene: Perform hand hygiene before and after patient contact, after contact with potentially infectious material, and before performing aseptic tasks.
Personal Protective Equipment (PPE): Based on the anticipated exposure to infectious material, wear appropriate PPE, such as gloves, gowns, masks, and eye protection.
Respiratory Hygiene/Cough Etiquette: Instruct patients and healthcare personnel to cover coughs and sneezes, use tissues, and perform hand hygiene.
Safe Injection Practices: Use sterile, single-use disposable needles and syringes for each injection.
Environmental Cleaning: Ensure that the environment is routinely cleaned and disinfected.
Waste Disposal: Properly dispose of medical waste and sharps in designated containers.

Hand Hygiene Chart

Situation	Action
Before patient contact	Perform hand hygiene
After patient contact	Perform hand hygiene
After contact with potentially infectious material	Perform hand hygiene
Before performing aseptic tasks	Perform hand hygiene
After removing gloves	Perform hand hygiene

Transmission-Based Precautions

Transmission-based precautions are additional infection control practices used for patients who are known or suspected to be infected with highly transmissible or epidemiologically significant pathogens.

Types of Transmission-Based Precautions

There are three types of transmission-based precautions: contact precautions, droplet precautions, and airborne precautions.

Contact Precautions

Used For: Infections that can be spread by direct or indirect contact with the patient or the patient’s environment.
PPE: Gloves and gown for all interactions that may involve contact with the patient or their environment.
Room: Private room if possible, or cohorting with patients with the same infection.

Droplet Precautions

Used For: Infections spread through respiratory droplets.
PPE: Mask for close contact with the patient; gloves and gown if contact with secretions is likely.
Room: Private room or cohorting with patients with the same infection.
Patient Transport: Minimize transport; patient should wear a mask if transport is necessary.

Airborne Precautions

Used For: Infections spread through airborne particles.
PPE: N95 respirator or higher-level respirator for healthcare personnel entering the room.
Room: Airborne infection isolation room (AIIR) with negative pressure ventilation.
Patient Transport: Minimize transport; patient should wear a mask if transport is necessary.

Transmission-Based Precautions Chart

Type	Used For	PPE	Room	Patient Transport
Contact Precautions	Infections spread by direct or indirect contact	Gloves, gown	Private room or cohorting	Standard precautions
Droplet Precautions	Infections spread by respiratory droplets	Mask, gloves, gown	Private room or cohorting	Minimize transport; mask patient
Airborne Precautions	Infections spread by airborne particles	N95 respirator	AIIR with negative pressure	Minimize transport; mask patient

Practice Exercises

Practice the following scenarios to enhance your understanding of modes of transmission and precautions:

Identify the mode of transmission for influenza, tuberculosis, malaria, and MRSA and suggest appropriate precautions for each.
Demonstrate the proper use of PPE for a patient under droplet precautions.
Create a checklist for environmental cleaning and disinfection in a healthcare setting.
Explain the steps for performing hand hygiene according to standard precautions.

Conclusion

Understanding the modes of infectious transmission and implementing the appropriate precautions are essential for preventing the spread of infections. By following standard and transmission-based precautions, healthcare professionals can protect themselves and their patients from infectious diseases.