1. The Immune System and Disease
              
              
              

2. Infectious Disease What is a disease?
Any change, other than an injury, that disrupts the normal functions of the body.
Some diseases are produced by pathogens, such as bacteria, viruses, and parasites. Others are caused by materials in the environment, such as cigarette smoke. Still others, such as hemophilia, are inherited.

3. The Germ Theory of Disease
Louis Pasteur and Robert Koch
Infectious disease caused by microorganisms
Koch
Pasteur

4. Agents of Disease Viruses Bacteria Protists Worms Fungi
Influenza and Warts
Bacteria
Botulism and Anthrax
Protists
Malaria and African Sleeping Sickness
Worms
Schistosoma and Tapeworms
Fungi
Athlete’s foot and Ringworm

5. How Bacteria Produce Disease
Some bacteria damage the cells and tissues of the infected organism directly by breaking down the cells for food.
Others release toxins, which are poisons that travel throughout the body and interfere with the normal activity of the host.

6. Diseases Caused by Bacteria
Lyme disease
Tetanus
Tuberculosis
Anthrax
Bacterial meningitis
Strep throat
Salmonellosis
Tooth decay

8. Preventing Bacterial Disease
Many bacterial diseases can be prevented with vaccines.
Vaccines are preparations of weakened or killed pathogens used to produce immunity to the disease.
If infection does occur, antibiotics are used to block the growth and reproduction of bacteria.

9. Penicillin and Bacteria
The cell wall of a bacterium is made of sugars and amino acids
Penicillin stops the enzyme that links the sugar chains
Holes develop in the cell wall, the bacterium ruptures and dies

10. Controlling Bacteria
Most bacteria are harmless and many are beneficial, but efforts are still made to control bacterial growth in order to reduce the risk of infection.
Sterilization by heat
Disinfectants like soap and chemicals (overuse can lead to resistant strains)
Refrigeration, cooking, and canning of foods

11. Viral Disease
Like bacteria, viruses produce disease by disrupting the body’s normal equilibrium.
Viral diseases cannot be treated with antibiotics.
The best protection from viruses is prevention of disease, especially vaccination.

12. Diseases Caused by Viruses
Common cold
Influenza
Smallpox
Warts
AIDS
Chickenpox
Measles
Ebola
West Nile
Polio

13. Viral Disease in Plants
Viruses that infect plants threaten many agricultural crops.
Viruses have a hard time entering plant cells because of the cell wall.
Most plant viruses are adapted to take advantage of small breaks in the cell wall.
Insects are also responsible for spreading plant viruses as they feed on plants.

14. How Diseases are Spread
Physical Contact
Direct: shaking hands, sex
Indirect: through the air or on objects
Contaminated Food and Water
Infected Animals (Vectors)

15. The Immune System
The immune system is the body’s defense against pathogens (“Sickness-makers”)
The immune system recognizes, attacks, destroys and remembers each type of pathogen that enters the body.
The function of the immune system is to fight infection through the production of cells that inactivate foreign substances or cells.
This process is called immunity.

16. Defense Level 1—Barriers
Barriers, which physically block pathogens from entering the body are the first line of defense.
Skin, hair, mucus, sweat, tears, coughing, sneezing, and stomach acids

17. Defense Level 2—Nonspecific
Innate Immune Response is a rapid response to all pathogens in the same generalized way
Inflammation—increased blood flow delivers defense molecules
Phagocytes—white blood cells
Complement System—proteins coat pathogens

18. Defense Level 3—Antibodies
Adaptive Immune Response—slower, acquired defense dependent on the recognition of specific pathogens
Recognition of antigens on the surface of pathogens
Antibodies bind to and inactivate antigens
Once the body has been exposed to a pathogen, memory B cells remain capable of producing antibodies to it.

19. Defense Level 3—T Cells
When pathogens get inside cells, antibodies alone cannot kill them.
T cells kill or help kill antigens
T cells are a problem with transplants, and drugs must be taken to prevent rejection.

20. Acquired Immunity
Active Immunity—produced by the body’s reaction to a vaccine or infection
Passive Immunity—antibodies produced by another animal are injected or passed from mother to child, lasts a short time

21. Acquired Immunity

22. Immune System Disorders

23. Allergies Overreaction of the Immune System
                              
Overreaction of the Immune System
Antigens that cause allergic response are called allergens.
Histamines released cause sneezing, watery eyes, and other irritations

24. Autoimmune Diseases
The immune system makes a mistake and attacks the body’s own cells.
Type I diabetes—insulin-producing cells
Rheumatoid arthritis—connective tissue
Myasthenia gravis—neuromuscular junctions
Multiple sclerosis—neurons in brain and spinal cord

25. AIDS an Immunodeficiency Disease
HIV infection destroys helper T cells causing the immune system to break down.
Acquired Immune Deficiency Syndrome
Opportunistic diseases attack

26. Transmission of HIV AIDS is deadly, but it is NOT easily transmitted!
ANY form of sexual intercourse
Shared needles or syringes
Contact with blood or blood products
From mother to child during pregnancy or breastfeeding
It is NOT transmitted by casual contact (i.e. shaking hands, hugging, kissing on the cheek)

27. Preventing HIV Infection
The only no-risk behavior with respect to HIV and AIDS is abstinence.
Avoid drug use and contaminated needles.
Transmission through blood transfusions has been nearly eliminated
due to screening of the blood supply and
discouraging potentially infected individuals from donating.

28. Can AIDS Be Cured? At present, there is no cure for AIDS.
Multidrug and multivitamin “cocktails” make it possible for people to survive HIV infection for years.
                                                                 

29. What About a Vaccine? No vaccine is available due to the rapid rate
of HIV virus mutation.
The AIDS Memorial Quilt
The total number of deaths from AIDS worldwide is now more than 35 million people.