Chapter 28: Infectious Diseases p. 619

Chapter 28: Infectious Diseasesp. 619 Lesson 1: What Causes Infectious Diseases? P. 620

Health Terms p. 620 • Infectious diseases • Parasites • Virus • Transmission • Immunity • Mucous membranes • Phagocytosis • Neutrophils • antibodies

Causes of Infectious Diseases • Every infectious disease is caused by a pathogen. • Pathogens invade the body and attack it’s cells and tissues. • Most pathogens are parasites.

Bacteria • Single-celled microorganism • Can live almost anywhere • Some produce poisons that are harmful to human cells • Abundant in the air, soil and water • Upon entering the body, they multiply rapidly through cell-division • Division can take place every 20min. • 1 bacterium can be 4 billion in just 15 and 1/2 hours • Usually body’s immune system does not allow this

Viruses • Smallest infectious agent • HIV is one of the deadliest known viruses; it causes AIDS • Are not living cells • Invade all known forms of life • Viruses very specific in the cells it invades • Upon entering the body, it attaches to a cell and injects its genetic material in that cell. The virus then makes copies that repeat the process • Usually killed by immune system

Rickettsias • Organisms that resemble small bacteria • Act like viruses in that they need to invade the cells of another life form • Most are found in the intestinal tract of insects • Rickettsias are passes to human or animal by bites or feces deposits on the skin • Typhus • Rocky Mountain Spotted Fever

Protozoans • Single-celled • Larger than bacteria • Most are harmless • About 30 types causes disease in humans • Most common in tropical areas that have poor sanitation Fungi • Simple organisms • Prefer dark, damp environments • Most invade deep tissues of hair, nails and skin causing infections of the scalp and feet • Examples are ringworm and athletes’s foot

How Infectious Diseases Spread • People • Direct contact - when an uninfected person comes in to physical contact with an infected person. • Sexually Transmitted Diseases (STD’s) are spread this way • Pregnant women may transmit infection to an unborn child

How Infectious Diseases Spread cont’d • People cont’d • Indirect contact- Pathogens spread through the air or other means of transmission other than direct contact. • Pathogens can be spread through touching contaminated objects.(Desk, utensils, glasses or needles) • Pathogens can be spread through the environment. (Food, water, soil, and even the air)

How Infectious Diseases Spread cont’d • Animals • may spread infectious diseases such as Malaria or Rabies.

How Your Body Defends Against Infectious Disease How does your body remain health? Immunity • Your immune system fights millions of pathogens each day • thus keeping your body mostly free of infection. • Nonspecific Resistance- Inborn, or general, defenses against infection • When nonspecific, the body responds the same way to every foreign substance • 4 types:

The Immune Response Nonspecific Resistance • Physical barriers • Skin first line of defense against invading pathogens, the main barrier • Mucous membrane/mucous • Cil

The Immune Response cont’d Nonspecific Resistance cont’d • Chemical Barriers • Enzymes in tears • Acidic digestive juices • Body Cells • White Blood Cells (WBC) • Phagocytes • Neutrophils - chief phagocytes

The Immune Response cont’d Nonspecific Resistance cont’d • Inflammatory response • “Red Alert” stage, increased blood flow. • Symptoms include heat, redness and swelling • Once pathogens are destroyed, tissues return to normal.

Specific Resistance • Immune system mounts specific attacks against particular types of pathogens. • Lymphocytes- Type of white blood cell that fights pathogens. • Two main types of lymphocytes are B cells and T cells.

Specific Resistance cont’d • B cells- Enlarge and multiply, eventually turning into antibodies. If you encounter the same specific pathogen again, the antibodies are still there to fight. • T Cells- Two main types. • Killer T cells - multiply by the presence of abnormal body cells; they then fight to kills the abnormal cells • Helper T cells - aid the activity of the B and Killer T cells.

Specific Resistance cont’d When you fail to take in adequate nutrients, you can jeopardize the immune system. This is why those with poor eating habits tend to get more sick.

Chapter 28: Infectious Diseasesp. 619 Lesson 2: Common Infectious Diseases p. 627

Health Terms • Pneumonia • Tuberculosis (TB) • Strep throat • Vaccine • Immunization • Rubella

Respiratory Infections Infections of the breathing passages, most of these are caused by a virus or a bacteria. • Common Cold - viral infection, inflammation of the mucous membranes lining the nose and throat. • Mostly contracted by breathing in virus • sneezed or coughed by an infected person, • or rubbing the eyes or nose with fingers that picked up the virus • by direct contact or indirect contact • There is no cure, but most clear up in a week or so. The best treatment is rest, proper nutrition, and drinking plenty of fluids.

Respiratory Infections cont’d • Influenza (The Flu)- viral infection, spread and treated the same way as cold. • Major breakouts generally occur in the winter. • Secondary bacterial infection may accompany the flu • which can develop in to pneumonia (A serious inflammation of the lungs) • Secondary infections need antibiotic treatment

Respiratory Infections cont’d • Tuberculosis (TB)- Highly contagious bacterial infection that most often affects the lungs. • Spread by airborne droplets produced by coughing or sneezing. • Main symptoms include coughing, chest pains, shortness of breath, fever, sweating, and weight loss.

Respiratory Infections cont’d • Strep Throat - A bacterial infection of the throat. • Spread through droplets coughed or sneezed in the air. • Symptoms include sore throat, fever, general feeling of sickness and enlarged lymph nodes in the neck. • If left untreated can lead to serious complications. • Strep can be cured with antibiotics.

Infectious Diseases of the Nervous System • Encephalitis • Inflammation of the brain • Often caused by a virus carried by a mosquito • No known cure • Can be caused by herpes simplex virus • If can be cures with an antiviral

Infectious Diseases of the Nervous System cont’d • Meningitis • An inflammation of the membranes that cover the brain and spinal cord • Viral illness is mild • Bacterial is life-threatening • Poliomyelitis (Polio) • Viral • 1950 to scientists developed a vaccine

Measles • viral • Fever • Total body rash • Can cause encephalitis • Vaccine - part of the MMR series

Mononucleosis • “Mono” • “Kissing Disease” • Usually spread through direct contact • 3-6 weeks for recovery

Hepatitis • Inflammation of the liver • Can result in permanent damage • Common symptom is yellowing skin and eyes • Appear 3 - 4 weeks after exposure • Lasts 2 - 6 weeks

Hepatitis cont’d 3 Types of Hepatitis: • Hepatitis A • The virus is contracted by eating or drinking foods contaminated with the virus; food in contact with feses • Hepatitis B • Found in body fluids • Spread via blood and sexual contact • Can cause liver damage

Hepatitis cont’d • Hepatitis C • Found in blood • Can cause liver cancer NO CURE VACCINE FOR HEPATITIS B

Chapter 28: Infectious Diseasesp. 619 Lesson 3: Preventing Infectious Diseases p. 632

Health Terms • Active immunity • Passive immunity

IMMUNITY The body’s natural resistance to many pathogens 2 Types:

IMMUNITY cont’d • Active immunity - the body develops specific, long term antibodies to fight pathogens. • ie Chicken Pox virus enters and your body produces antibodies to kill that virus • Passive Immunity - infant acquires immunity through its mother while in womb and shortly after birth

Immunization Additional help to establish immunity against specific pathogens

Immunization cont’d • Passive immunization • Blood is taken from an infected person who has developed antibodies • An extract of that blood is injected into the person needing immunity help • Active Immunization • Also know as a vaccine • 3 types:

Immunization cont’d 3 Types of Active Immunization: • Live-virus vaccine • Made from weakened viruses • Help the person to produce antibodies and not get sick • Measles, rubella, & oral polio

Immunization cont’d • Killed-virus vaccine • Made from killed viruses • Helps a person to produce antibodies and not get sick • Less powerful than Live-Virus vaccine • Thus boosters are needed • Cholera, typhoid fever, rabies and injected polio

Immunization cont’d • Toxoid • Made with chemically treated bacteria toxins • These toxoids stimulate production of antibodies

Immunization for All Why do you think immunizations are important in the school setting?

Common Sense Measures • Keep your body healthy • Good nutrition • Adequate slee • Exercise • Bathe or shower every day • Avoid sharing eating & drinking utensils • Wash your hands after using the restroom or changing diapers

Common Sense Measures cont’d • Wash your hands before handling food • Avoid giving your illness to others • Cover your mouth & nose when sneezing/coughing • Use tissues only once and dispose • Avoid contact with those who are sick

Test Review • Rickettsias resemble bacteria and are able to reproduce only by invading the cells of another life form. • Chief type of white blood cells involved in phagocytosis are neutrophils • TB is caused by a bacteria • B cells produce antibodies against pathogens • When they encounter a pathogen, B cells turn into plasma cells. • Meningitis is an inflammation of the membranes that cover the brain and spinal cord.

A live-virus vaccine is a type of vaccine made from a weakened virus. • Hepatitis is an inflammation of the liver usually caused by a viral infection in which the skin and the whites of the eyes turn yellow. • Know ALL of your vocabulary!!! • Page 638- 1-17 • Directions- Write the answer, then take the answer and use it in a sentence that you either made up or found in the book. Sentences should show knowledge of the def.

Chapter 28: Infectious Diseases p. 619