1. Chapter 28 Infectious Diseases
Lesson 1
What Causes Infectious Diseases?

2. Lesson 1 Objectives:
Describe the types of pathogens that cause disease.
Discuss the spread of bacterial infection through cell division.
Describe how viruses differ from other pathogens.
Identify the major routes for the spread of infectious diseases.
Describe the two main types of defenses used by the immune system

3. Causes of Infectious Diseases
Caused by one of several types of microorganisms known as pathogens
Pathogens invade body and attack its cells and tissues
Most are parasites (organisms that live in or on another organism and derive nourishment from it)

4. Forms of Pathogens
Bacteria
Viruses
Rickettsias
Protozoans
Fungi

5. Bacteria Single-celled microorganism Abundant in air, soil, and water
When bacteria enter body, they multiply rapidly through cell division
A healthy immune system destroys invading bacteria

6. Viruses Smallest known type of infectious agent Are not living cells
Consist of inner core of genetic material surrounded by protective protein shell
Dependent upon living cells for survival and reproduction
Invade all forms of life
Attaches to hosts and injects genetic material into that cell
Make copies of self and spread until immune system kills them
Add notes page Picture is of flu virus.

7. Rickettsias
Organisms that resemble small bacteria but can only multiply by invading the cells of another life form
Most found in intestinal tracts of insects, mice, ticks and mites
Passed on through bites or through feces deposited on the skin
Includes diseases like typhus and Rocky-Mountain spotted fever

8. Protozoans
Single-celled organisms larger than bacteria with a more complex cell structure
Most are harmless but 30 cause human disease
Most common in tropical areas that have poor sanitation

9. Fungi Simple organisms that cannot make their own food
Many are saprophytes – organisms that feed off dead animals, insects, and leaves
Prefer dark environments
Most common ones invade deep tissues of hair, nails, and skin and cause infections of scalp or feet such as ringworm or athletes foot
Top is ringworm bottom is athlete’s foot.

10. How Infectious Diseases Are Spread
People
Direct contact
Ex. STD’s, human bite, pregnant woman to child
Indirect contact
Bacteria and viruses can enter body through lungs if droplets are inhaled (cold, flu and TB)
Animals
Ex. Dog or mosquito bites
Contaminated Objects
Utensils, glasses, toothbrushes, needles
The Environment
Food, water, soil and air
How many of you share chapstick with others or drink out of the milk jug at home?

12. How Your Body Defends Against Infectious Diseases
The Immune Response
Innate immune system
Inborn defenses provide nonspecific resistance
Adaptive immune system
Provides specific resistance

13. How Your Body Defends Against Infectious Disease
Nonspecific Resistance
Physical Barriers
Unbroken skin
Mucous membranes – soft, skin-like lining of mouth, nose or bronchial tubes trap pathogens to be expelled during cough or sneeze
Chemical Barriers
Enzymes in tears and saliva destroy bacteria
Body Cells
Phagocytes- white blood cells that group together in blood to destroy pathogens in a process called phagocytosis
Inflammatory Response
Chemicals are released that cause blood vessels to dilate and allow increased blood flow so phagocytes can leave blood and kill pathogens in the tissues
Add notes page Symptoms of inflammation include heat, redness, and swelling from increased blood flow.
Inflammation was desired when prolotherapy was used on my sore shoulder. Sugar was injected. I could not ice or take anti-inflammatory meds.

14. The major passages and structures of the upper respiratory tract include the nose or nostrils, nasal cavity, mouth, throat (pharynx), and voice box (larynx). The respiratory system is lined with a mucous membrane that secretes mucus. The mucus traps smaller particles like pollen or smoke. Hairlike structures called cilia line the mucous membrane and move the particles trapped in the mucus out of the nose. Inhaled air is moistened, warmed, and cleansed by the tissue that lines the nasal cavity.

15. Phagocytosis at Word
Phagocytes- white blood cells that group together in blood to destroy pathogens in a process called phagocytosis

16. Inflammatory Response at Work
Chemicals are released that cause blood vessels to dilate and allow increased blood flow so phagocytes can leave blood and kill pathogens in the tissues
Inflammatory Response at Work

17. How Your Body Defends Against Infectious Diseases
Specific Resistance
Lymphocytes kick in when general responses are not adequate to protect your body from disease
Type of white blood cell that fights pathogens
Travel through 2 networks – blood vessels and lymph system
2 types of lymphocytes
B cells
Turn into plasma cells which produce antibodies (proteins that destroy or neutralize invading pathogens)
T cells
Killer cells- stimulated to multiply by presence of abnormal body cells
Helper cells – aid activity of B cells and killer T cells

19. Care of the Immune System
Requires good nutrition
Negatively affected by ultraviolet rays

20. Chapter 28 Infectious Diseases
Lesson 2
Common Infectious Diseases

21. Respiratory Infections
Infections of breathing passages (nose to alveoli of lungs)
Most illnesses caused by viruses or bacteria

22. Respiratory Infections
Common Cold
Influenza
Tuberculosis

23. Common Cold No cure Most clear up in 1 week
Viral infection
Causes inflammation of mucous membranes lining the nose
Symptoms – stuffy, runny nose, sneezing and sometimes sore throat and headache
Contracted by breathing in virus-containing droplets released by others or rubbing eyes or nose with contaminated hands
No cure
Most clear up in 1 week
Treatment – rest, proper nutrition and plenty fluids

25. Influenza Viral infections of respiratory tract
Symptoms – chills, fever, headache, muscle ache, and weakness
Spread by droplets
Major outbreaks occur every few years usually in the winter
Treatment – rest, proper nutrition and plenty fluids
Secondary bacterial infection can follow – especially in elderly and people with lung or heart problems leading to pneumonia (serious inflammation of lungs
Secondary requires antibiotics

27. Tuberculosis
Highly contagious bacterial infection that most often affects lungs
Spread by airborne droplets from coughing or sneezing breathed in and multiplied
Immune system usually stops it unless spreads through lymphatic system to nodes
Bacteria may enter bloodstream and spread or become inactive for years only to be reactivated later
Usually affects lungs
Symptoms – coughing, chest pain, shortness of breath, fever, sweating, poor appetite and weight loss

29. Granulomas are nodules of inflammation in tissues.
Before antibiotics, TB was a major cause of death in US. Modern meds were effective but during 1980’s antibiotic-resistant strains of bacterium that cause TB appeared. This made standard treatment ineffective and the incidence of TB began to rise.

30. Strep Throat Bacterial infection Spread by droplets in air
Symptoms – sore throat, fever, general feeling of illness, and enlarged lymph nodes in the neck
If untreated, can lead to serious complications such as inflammation of kidneys or rheumatic fever which can cause permanent heart damage
Cured with antibiotics

31. Infectious Diseases of the Nervous System
Some can have serious consequences if not caught and treated early
Encephalitis
Meningitis
Poliomyelitis

32. Encephalitis
Inflammation of brain usually caused by virus carried by mosquitoes
Starts as headache and fever
If untreated, can progress to hallucinations, confusion, paralysis, and disturbances of speech, memory, behavior, and eye movement
Can lead to gradual loss of consciousness and sometimes coma
If caused by herpes simplex virus, the antiviral med acyclovir may be effective
When caused by other viral infections, no known treatment

34. Meningitis
Inflammation of meninges (membranes that cover the brain and spinal cord)
Viral is mild, bacterial is life-threatening
Organisms reach meninges through bloodstream from an infection elsewhere in body
Symptoms – fever, severe headache, nausea, and vomiting, sensitivity to light, and stiff neck
Viral symptoms resemble flu and require no treatment
Bacterial is treated with antibiotics

35. Meningitis
Severe stiffness in hamstrings won’t allow leg to be straightened when hip is flexed to 90 degrees.

36. Poliomyelitis (Polio)
Disease of central nervous system caused by a virus
In serious cases, may lead to extensive paralysis including muscles used in breathing
Vaccine - a preparation based on a weakened or dead pathogen that provides immunity by causing the body to produce antibodies to the pathogen
Disease has begun to reemerge among people not vaccinated

37. Polio paralysis

38. Measles Highly contagious viral disease
Stars with fever, runny nose, sore eyes and cough
In 3-4 days, red rash appears
Ear and chest infections
Rare but serious complications like encephalitis
Immunizations help
Rubella or German measles – viral disease with similar symptoms, causes only minor infection in children but serious consequences in early pregnancy resulting in severe birth defects

39. Measles
Add notes page 630

40. Mononucleosis Viral infection common to teens
Symptoms – chills, fever, sore throat, fatigue and swollen lymph nodes
Spreads by direct contact – “kissing disease”
Virus multiplies in lymphocytes
Complete bed rest
Recovery can take 3-6 weeks

42. Hepatitis Inflammation of liver
Toxic type may be caused by certain drugs, chemicals or poisons
Symptoms – jaundice (yellowing skin and eyes), fever, nausea, loss of appetite, pain in abdomen, aching muscles, and sometimes joint pain
Could result in permanent liver damage
Symptoms appear in 3-4 weeks of exposure and last 2-6 weeks

43. Hepatitis

44. Hepatitis A
Results from eating food or drinking water contaminated with the virus from an infected person’s feces
Cases occur among people who have traveled to areas where standards of hygiene are low

45. Hepatitis B Hepatitis B
Found in all body fluids of infected person especially blood
Spread by contaminated med instruments, sexual contact and shared hypodermic needles
More serious than A - can lead to chronic infection and liver damage
Add notes page 631

46. Hepatitis C Spread through infected blood Can cause liver cancer
No cure but vaccine available
Treatment – rest, proper nutrition and injesting plenty fluids

47. Chapter 28 Infectious Diseases
Lesson 3
Preventing Infectious Diseases

48. Immunity Immunity – body’s natural resistance to many pathogens
Active Immunity
Body remembers pathogens it meets – giving long lasting immunity
Some last lifetime, others short time
Passive Immunity
Temporary immunity that an infant acquires from its mother
Add notes from pages

49. Immunization When body needs help to establish immunity 2 Types
Passive
Immediate and short-lived protection
An extract of blood from a person (or animal) that has been exposed to microorganism is injected into person who needs to be protected
Active (vaccination)
Contains substances strong enough to cause the production of the desired antibodies but not strong enough to cause the disease

50. 3 Major Types of Vaccines
Live-virus vaccines
Made from weakened viruses
Ex. – measles, rubella and oral polio
Killed-virus vaccines
Cause the body to produce antibodies but not as powerful as live-virus vaccines so need boosters
Ex. – cholera, typhoid fever, rabies and Salk injected polio
Toxoids
Treated toxins stimulate the production of antibodies and establish active immunity against diseases

51. Nasal flu vaccine is a live virus while traditional one is a killed type.

52. Immunizations for All Not just good idea, the law
Up-to-date immunizations to enter kindergarten
Why do you think immunizations are so important in a school setting? Add notes pages

53. Common Sense Measures
Form groups of two and brainstorm what you can do to protect yourself from being infected by disease. Think in terms of ways to avoid contact with the pathogens and ways to avoid spreading the pathogen.
Let’s see who came up with the most ideas.

54. Common Sense Measures Keep body healthy so it can resist infection
Good nutrition, regular exercise, adequate sleep, good health care
Bathe or shower every day to keep, skin, hair and nails clean
Avoid sharing eating or drinking utensils
Store and prepare food in safe ways
Wash hands after using bathroom, changing diapers and before working with food
If sick, avoid giving illness to others. Cover mouth. Use tissues once and discard.
If you are well, avoid contact with people who are not
Add animation to drop these slides in after students have had time to share brainstormed ideas on previous page.