Disease Transmission and Infection Control Medical Foundations

Objectives Introduce microorganisms Become familiar with infections and control measures Introduce the need for standards and precautions Become familiar with sterile environments

Introduction to Microorganisms Pathogenic microorganisms: cause illness, infection, or disease Nonpathogenic microorganisms: help keep a balance in the environment and in the body

Microorganism Survival Most microorganisms that cause disease – Thrive in warm temperatures How warm is the human body? – Need moisture How much of the human body is made up of water? – Prefer a dark area to grow in – Need food Some live on dead tissue (saprophytes), some live on live tissue Some need oxygen (aerobic), some do not need oxygen (anaerobic)

Nonpathogenic Microorganisms “Good” microorganisms are used in a variety of ways: examples? (P. 489) Buttermilk, fermenting alcohol, making bread rise Where do nonpathogenic microorganisms live in your body and what do they do?

Types of Pathogens Bacteria – One celled plants – Classified by shape and arrangement – Causes strep throat, staph infections, syphilis

Protozoa – One celled animals – Found in water and soil environments decayed material and contaminated water – Cause amebic dysentery and malaria Types of Pathogens

Fungi – Simple, low form of plant life – May live on dead matter – Yeasts, molds – Causes athlete’s foot, thrush, vaginitis, and serious lung diseases Types of Pathogens

Rickettsiae Parasitic microorganism – Transmitted to humans through the bite of lice, fleas, ticks, and mites – Responsible for some of the world’s worst epidemics – Rocky Mountain spotted fever – Typhus

Types of Pathogens Viruses – Smallest microorganism, smaller than bacteria – Can only reproduce inside humans cells – Causes common cold, upper respiratory infections, smallpox, chickenpox, measles, mumps, influenza, fever blisters – Also cause HIV which can lead to AIDS

Additional Classifications Endogenous – Originates inside the body Exogenous – Originates outside the body Nonsocomial – An infection acquired inside the hospital Opportunistic – Infections that occur when the body’s immune system is weak

How Microorganisms Affect the Body Production of toxins – Staphylococcus produces enterotoxin that causes food poisoning = fatigue, diarrhea, vomiting – Tetanus bacilli produces a toxin that attacks the central nervous system = damage, possible death Cell invasion – A protist can enter red blood cells, making them rupture = chills and fever Allergic reactions – Allergies = runny nose, watery eyes, sneezing

Chain of Infection

How Microorganisms and Viruses Spread Direct Contact Indirect Contact Airborne Oral Route Insects and Pests (Pg. 493)

Disease Prevention Standard Precautions and Transmission-Based Precautions were created to provide guidelines that prevent the spread of microorganisms. Signs and Symptoms—Which is which? – Infections can be generalized or localized Affecting all of the body Affecting one area of the body – Give signs and symptoms of each