Chapter 12 Infectious Diseases Lesson 12 1 Infectious

Chapter 12 Infectious Diseases Lesson 12. 1 Infectious Diseases: What You Should Know Lesson 12. 2 Transmission, Treatment, and Prevention of Infectious Diseases Lesson 12. 3 Immunity to Infection

Lesson 12. 1 Infectious Diseases: What You Should Know

Warm-Up Infectious Diseases What are some causes of infectious diseases? How are infectious diseases transmitted? What are some ways of treating infectious diseases? Courtesy of the Centers for Disease Control and Prevention Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Infectious Diseases • Caused by microorganisms (pathogens) living in or on humans, animals, or plants • Also called communicable diseases because they can be transmitted from one living thing to another shutterstock. com/wavebreakmedia Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Signs and Symptoms of Disease • Signs are evidence of disease that can be outwardly observed or measured – Fever – An abnormal pulse • Symptoms are evidence of disease sensed by the sick person – Pain – Shortness of breath shutterstock. com/bikeriderlondon Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

How Do Infections Cause Illness? • After pathogens enter the body, they grow, reproduce, and produce toxins • Toxins cause the familiar symptoms and signs of illness – Pain – Inflammation – Headache shutterstock. com/S_L Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Think Further Infections often follow stages in a recognizable pattern. What are three common stages of an infection? – The incubation period is the time between the pathogen’s entrance into the body and the first appearance of symptoms. – In the clinical stage, signs and symptoms of a disease arise and are most prominent. – In the convalescent stage, signs and symptoms of a disease fade and a person is no longer contagious. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Microorganisms • Include bacteria, viruses, fungi, and parasites • Are found everywhere and are typically invisible to the naked eye • Are diverse, specialized, and sophisticated shutterstock. com/kurhan Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Bacteria • Single-celled organisms • Most are helpful and few of them cause disease • Most bacteria can grow independently outside of your cells shutterstock. com/science photo Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Viruses • Pathogens that infect cells • Cannot reproduce or grow on their own • Very small, cannot be seen with ordinary microscopes • Cause the common cold and other illnesses shutterstock. com/Subbotina Anna Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Critical Thinking Viruses Everyone knows about the common cold and influenza, which are notorious viral diseases. What are some lesser known but important viral diseases? Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Fungi • Fungi include mushrooms, molds, and yeast • Few fungi cause disease and many are beneficial • A fungal infection, such as athlete’s foot, is called a mycosis shutterstock. com/pedalist Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Parasites: Protozoa and Worms • Parasites are organisms that must live inside or on another living thing • They cause damage and disease • Parasitic worms and protozoa infect a great number of people shutterstock. com/Path. Doc Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Protozoa • Protozoa are singlecelled organisms • Certain protozoa cause diseases – Malaria – Dysentery – Diarrhea Courtesy of the Centers for Disease Control and Prevention Mosquitoes play a part in transmitting malaria. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Worms • Parasitic worms are multicellular organisms with specialized tissues and organs • Methods of transmission – In water or food that has been contaminated with human waste – In undercooked meat and fish shutterstock. com/moreimages Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Lesson 12. 2 Transmission, Treatment, and Prevention of Infectious Diseases

Methods of Transmission • A method of transmission is simply the way a disease gets from one organism to another • Methods of transmission are classified as either direct or indirect shutterstock. com/Siberia-Video and Photo Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Direct Transmission • The exchange of infectious material from its origin to a susceptible individual • Direct contact – Sexually transmitted infections – Skin infections • Droplet spread – Sneezing – Coughing shutterstock. com/JPC-PROD Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Indirect Transmission • The exchange of infectious material to a susceptible person by a source that acts solely as a carrier – By animals – By contaminated objects – By airborne means thinkstock. com/i. Stock/Mike. Lane 45 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Think Further What are some diseases that could be spread through contaminated water? – – – E. coli Hepatitis Typhoid Cholera Other parasitic infections Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Occurrence of Infectious Disease • Diseases and other infections follow patterns • An epidemic infection occurs in unexpectedly large numbers • A pandemic infection affects an enormous number of people and spreads to much of the world • An endemic infection naturally occurs at low levels in a particular area • Emerging infectious diseases are new or increasing unexpectedly Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Prevention of Infectious Diseases • Effective preventive measures can reduce the incidence of infectious diseases • Doctors recommend covering your nose and mouth with a tissue when coughing or sneezing • Vaccination can help stop the spread of an infectious disease shutterstock. com/MSPhotographic Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Think Further Myth or Fact? Hand washing is not really important in preventing the spread of infectious diseases. MYTH – Fact: Hand washing reduces the occurrence of infectious diseases that are transmitted by respiratory droplets, blood, or direct skin contact. – Fact: Alcohol-based hand rubs are very effective when soap and water are unavailable. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Food Sanitation • Used to prevent contamination during food processing, storage, and preparation – Avoid nonpasteurized drinks – Refrigerate and freeze perishables – Cook meat thoroughly – Wash vegetables and fruits – Use safe drinking water shutterstock. com/Olesya Feketa Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Treating Bacterial Infections • Antibiotics are substances that target and kill many kinds of pathogenic bacteria • Most antibiotics are prescription medications • A few antibiotics can be purchased at drugstores without a doctor’s prescription shutterstock. com/Sheila Fitzgerald Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Critical Thinking Antibiotic Resistance Several strains of bacteria have developed antibiotic resistance and cannot be killed by antibiotics. What are some steps that can help prevent antibiotic resistance? Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Treating Viral Infections • There are few treatments for viral infections • Most medications target the symptoms and do not attack the virus • Medications can help keep the virus under control while the body fights the infection shutterstock. com/Poznyakov Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Lesson 12. 3 Immunity to Infection

The 5 major barriers of protection 1. Integumentary system- Your SKIN!!! 2. Tears 3. Saliva 4. Stomach Acid 5. Mucous Membranes Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

The First Line of Defense • The immune system continually defends the body against infection • The body’s skin (integumentary system) forms a nearly impenetrable barrier to pathogens • The body’s inner surfaces also have protection in the form of mucous membranes shutterstock. com/Michaelpuche Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Other System Defenses Helpful bacteria occupy the large intestine and inhibit the growth of pathogens. shutterstock. com/xrender • The respiratory system is protected by mucus • In the digestive system, mucus coats the throat, esophagus, stomach, intestines, and rectum • The regular flow of urine flushes microorganisms from the urinary system Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

The Second Line of Defense • A phagocyte is a white blood cell that destroys microorganisms • Inflammation prepares the body to control and remove pathogens • Fever stimulates phagocytes and other white blood cells important for immunity Click here for the “Events of Phagocytosis” animation Body Scientific International, LLC. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

The Third Line of Defense • The third defense system is made up of specialized cells and chemicals • T cells reside in the blood, lymph nodes, and spleen • A T-helper cell coordinates and stimulates the immune response • The T-cytotoxic cell attacks and kills cells in your body that have been infected with viruses shutterstock. com/docstockmedia Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Critical Thinking Promoting Resistance to Infection Resistance to infectious diseases depends on a healthy immune system and a healthy body. What are some steps that you can take to promote good health? Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

B Cells and Antibodies • B cells also reside in the blood, lymph nodes, and spleen, where they make special chemicals called antibodies • An antibody sticks to a pathogen, labeling it as foreign to the body • This makes it easier for phagocytes to find and engulf the pathogens Body Scientific International, LLC. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Immune System “Memory” • The B cells and T cells of the immune system remember encounters with pathogens • They can respond quickly to later exposures to these same pathogens • The immune response to later encounters can be so strong that you may not become ill at all • The immune system benefits from good nutrition and exercise • Some lifestyle choices, such as smoking, can suppress immunity Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.