chapter 12 infectious diseases lesson 12.1 infectious diseases: what you should know lesson 12.2...

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Chapter 12Infectious 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

Tuesday, October 20

Infectious Diseases: What You Should Know

Lesson 12.1

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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


• VIDEO: Protection from Infection

VIDEO


Infectious Disease Vocabulary

• Germ Theory: a scientific concept stating that specific microorganisms cause specific diseases.

• Infectious Diseases: are caused by microorganisms living in or on humans, animals, or plants.

• Pathogens: Microorganisms that cause disease.


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


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


Lesson 12.1 Signs and Symptoms

• For each medical scenario presented on the handout, differentiate between the signs and symptoms for each patient. If a patient does not exhibit either signs or symptoms, write “N/A” in the appropriate column.

• Work individually to complete the worksheet. • We will discuss the answers in 10 minutes!


Thursday, October 22 “A” Day

TODAYS AGENDA• Infectious Diseases: What you should know• Transmission, Treatment and Prevention of Infectious Diseases


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


Think Further

Infections often follow stages in a recognizable pattern. What are the 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.


Profile of an Infection: Strep Throat


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


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


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

http://safeshare.tv/v/ss5627bfd54ab81Ebola Virus

http://safeshare.tv/v/ss5627bfd54ab81

http://safeshare.tv/v/ss5627bfd54ab81


Critical ThinkingViruses

Everyone knows about the common cold and influenza, which are notorious viral diseases.

What are some lesser known but important viral diseases?Chickenpox.Flu (influenza)Herpes.Human immunodeficiency virus (HIV/AIDS)Human papillomavirus (HPV)Infectious mononucleosis.Mumps, measles and rubella.Shingles.


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


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/PathDoc


Protozoa

• Protozoa are single-celled organisms

• Certain protozoa cause diseases– Malaria– Dysentery– Diarrhea Mosquitoes play a part in

transmitting malaria.

Courtesy of the Centers for Disease Control and Prevention


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


Lesson 12.1 Key Concepts Review

• Complete the review worksheet and turn in to Mr. Nolan.

• Work quietly at your table when you finish the review worksheet.

Transmission, Treatment, and Prevention of

Infectious Diseases

Lesson 12.2


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


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


Infected People• Many infectious diseases are spread through some form of contact with a person who has the disease.

• The contact may be direct physical contact.

• Infectious diseases can also spread through indirect contact.


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/iStock/MikeLane45


Contaminated Objects• Some pathogens can survive for a period of time outside a person’s body.

• These pathogens can be spread from person to person on objects such as

• doorknobs• eating utensils• towels• needles used for body piercings and tattoos


Contaminated Food, Soil, or Water

• Some pathogens are naturally present in food and soil.

• Sometimes water and food become contaminated with pathogens from infected people.


Think Further

What are some diseases that could be spread through contaminated water?

– E. coli– Hepatitis– Typhoid– Cholera– Other parasitic infections


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


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

http://safeshare.tv/v/ss5627c1dfe1115How Vaccinations Work

http://safeshare.tv/v/ss5627c1dfe1115

http://safeshare.tv/v/ss5627c1dfe1115


Think Further

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.

Myth or Fact?


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


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


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?


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

Immunity to Infection

Lesson 12.3


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


Other System Defenses

• 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

shutterstock.com/xrender

Helpful bacteria occupy the large intestine and inhibit the

growth of pathogens.


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

Body Scientific International, LLC.

Click here for the “Events of Phagocytosis” animation

http://www.g-wlearning.com/health/9781619609488/student/ch12_03/video01.htm

http://www.g-wlearning.com/health/9781619609488/student/ch12_03/video01.htm


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 havebeen infected with viruses

shutterstock.com/docstockmedia


Critical Thinking

Promoting Resistance to Infection

Resistance to infectious diseases depends on ahealthy immune system and a healthy body.

What are some steps that you can take to promote good health?


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.


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


Your Immune System: Natural Born Killer

• http://safeshare.tv/w/OZFRLSljvH

http://safeshare.tv/w/OZFRLSljvH

http://safeshare.tv/w/OZFRLSljvH


Monday, May 4 “C” Day

chapter 12 infectious diseases lesson 12.1 infectious diseases: what you should know lesson 12.2...

Documents

accessible website

causes of infectious

specific diseases

infectious diseasescaused

communicable diseases

warmupinfectious diseases

evidence of disease

microorganisms pathogens