1. GERMS are EVERYWHERE!!!!! Glo Germ Activity
Who touched the doorknob when they came into the room today?
Eek! You’ve come in contact with GERMS!

2. Diseases Bolken 2015
Pathogen – a virus, microorganism, or other organism that causes disease; an infectious agent

3. Types of Pathogens
Bacteria: microscopic, unicellular creatures that get nutrients from their surrounding environments. Inside our bodies, they can cause infections.
Virus: not considered living things because they require a host to survive such as a person or plant. They can live for short periods of time on doorknobs, desks, and toilet seats. Viruses spread from person to person making us sick.
Fungi: microscopic, multicellular organisms that love damp, dark, warm places. They get nutrients by stealing it from plants or people.
Protists: unicellular organisms that can spread disease through water and cause intestinal diseases.

5. Lytic vs. Lysogenic Cycle
Life Cycle of a Virus
Lytic vs. Lysogenic Cycle
Have students summarize the diagram in their notes.

6. How are diseases transmitted?
Airborne – Tuberculosis bacteria, common cold virus
Foodborne – Food poisoning bacteria like salmonella
Waterborne – Cholera bacteria
Vector – an organisms that acts as an intermediate host that transfers a pathogen or parasite to another organism.
Malaria, protist carried by mosquito
Lyme Disease, bacteria carried by ticks
Plague, virus carried by rats (recent NYC news)
Touch/Contact – Rhinovirus (the common cold)
Bloodborne – AIDS
Sexual – AIDS, HPV

7. How can diseases be prevented?
WASH YOUR HANDS!!!
Have good personal hygiene
Cover your mouth when you sneeze (NOT with your hands, the proper way is to use the inside of your elbow)
Keep your kitchen counters clean
Wash raw fruits and vegetables
Wipe down cell phones, bags and purses that touch the floor, wallets, etc.
Get the recommended vaccines and keep them current with boosters
Be smart about sexual behaviors
Education – know how to protect yourself
Controlling animal vectors
Wildlife officials set out meat containing rabies vaccine for wild animals to consume

8. Vaccines: Disease Prevention
Vaccines are a highly effective way to prevent viral infections
Smallpox (eradicated), measles, mumps, rubella, chicken pox, polio, tetanus, diphtheria, pertussis
Vaccines are made by using dead or weakened forms of the virus to create immunity
Live, or attenuated, vaccines provide the greatest protection
Introduce antigens into the body to cause immunity without the risk of actual infection
The body creates memory cells which can be used during a secondary immune response

9. How are diseases cured?
Cures for most infectious diseases do not exist
Instead, treatment is provided
Bacterial diseases:
Antibiotics
Treat symptoms
Viral diseases:
Vaccines (prevention)
Run its course

10. The Immune System
Our immune system has three lines of defense against potential invaders:
Barrier defenses
Inflammatory Response
Leukocytes

11. Defense 1: Barriers
1. Mechanical Barriers – physically block pathogens from entering the body.
Skin – the single most important defense the body has.
Mucous membranes – provide protection at body openings and line the respiratory, GI, urinary, and reproductive tracts.
They secrete mucus, a slimy substance that traps pathogens.
Cilia – hair-like structures that sweep mucus and pathogens toward body openings where they can be removed from the body.
Sneezing and coughing – pathogens are removed from the nose and throat
Tears – wash pathogens from the eyes.
Urine – flushes pathogens out of the urinary tract.

12. Defense 1: Barriers
2. Chemical Barriers – destroy pathogens on the outer body surface, at body openings, and on inner body linings.
Sweat, mucus, tears, and saliva all contain enzymes that kill pathogens.
Urine is too acidic for many pathogens
Semen contains zinc, which most pathogens cannot tolerate
Stomach acid kills pathogens that enter the GI tract in food or water.
3. Biological Barriers – living organisms that help protect the body.
Millions of harmless bacteria live on the human skin and in the GI tract.
The harmless bacteria use up food and space so harmful bacteria cannot grow.

13. Defense 2: Inflammatory Response
What happens when you get a cut on your hand?
May become red, warm, swollen
Tissue damage or infection can cause inflammatory response

14. Defense 3: Leukocytes Leukocytes are your white blood cells
They are used in two kinds of responses
Non-specific defense
Specific defense

15. Non specific defense Same no matter what type of pathogen is involved.
Phagocytosis – when a leukocyte engulfs and breaks down a pathogen and debris

16. Specific defense Tailored to specific pathogens
Involves the lymphatic system – filters pathogens from lymph and produces lymphocytes in lymph nodes
This is why your lymph nodes become swollen when you’re sick
Lymphocytes – white blood cells that are activated by exposure to a particular antigen
B cells – produce antibodies to a particular antigen. Memory B cells remain in the body after the immune response is over and provide immunity to pathogens bearing the antigen.
T cells – destroy certain cancer cells and cells infected by viruses. Memory T cells remain in the body after the immune response and provide antigen-specific immunity to the virus.
Memory B and T cells help protect the body from re-infection by pathogens that infected the body in the past.

17. Specific defense
Immunity is the ability to resist infection by a pathogen.
Active immunity results from an immune response to a pathogen and the formation of memory cells.
Created through vaccinations
Passive immunity results from the transfer of antibodies to a person who has not been exposed to the pathogen.
Mother to child during pregnancy
Mother to child by breastfeeding

18. What is the benefit of a fever?
Moderate fevers (<103°F) are homeostatic mechanisms designed to slow the growth of pathogens that have invaded the body
Fevers above this would damage essential proteins and enzymes in the body
Low grade fevers are common after receiving live virus (attenuated) vaccines

19. Immune System Problems
Autoimmune diseases occur when the immune system fails to recognize the body’s own molecules as “self,” or belonging to the person. Instead, it attacks body cells as though they were dangerous pathogens.
Name of Disease
Tissues Attacked by Immune System
Results of Immune System Attack
Rheumatoid arthritis
tissues inside joints
joint damage and pain
Type 1 diabetes
insulin-producing cells of the pancreas
inability to produce insulin, high blood sugar
Multiple sclerosis
myelin sheaths of central nervous system neurons
muscle weakness, pain, fatigue
Systemic lupus erythematosus
joints, heart, other organs
joint and organ damage and pain

20. Immune System Problems
An allergy is a disease in which the immune system makes an inflammatory response to a harmless antigen. Any antigen that causes an allergy is called an allergen. Allergens may be inhaled or ingested, or they may come into contact with the skin.
Immunodeficiency occurs when the immune system is not working properly. As a result, it cannot fight off pathogens that a normal immune system would be able to resist.
HIV is a virus that attacks cells of the immune system and eventually causes AIDS. It is the chief cause of immunodeficiency in the world today.