1. Communicable Diseases
Lesson 44

2. Communicable Diseases
What you will learn:
Explain who the immune system responds when a pathogen enters the body.
Discuss ways to develop active and passive immunity.
Identify types of pathogens that cause disease, and give examples of the types of diseases caused by the types of pathogens.
Discuss ways pathogens are spread.
Analyze strategies to prevent infection with communicable diseases.

3. Communicable Diseases
Diseases affect people of all ages, races, and genders. Many of these diseases can be prevented when the facts about these diseases are known.
THE IMMUNE SYSTEM
If there are so many pathogens and they are everywhere, why aren’t we sick all the time?
Answer - Illness develops mainly when the body is compromised. When we are already sick, injured, under significant stress, not getting enough sleep.
Also, the body has systems in place to deal with pathogens.

4. Communicable Diseases
The first line of defense - general or non-specific resistance.
Physical Barriers
Unbroken skin acts as a barrier to prevent pathogens from entering the body.
Tears, perspiration, saliva, and oils on skin kill many pathogens.
Mucus and hairs that line the inside of the nose also trap and destroy pathogens.
Pathogens that are swallowed are destroyed by stomach acids.
Reflexes such as coughing, blinking and vomiting

5. Communicable Diseases
THE IMMUNE SYSTEM
When a pathogen gets past the first line of defense and enters the body, white blood cells called lymphocytes, help the body fight the pathogen.
There are 2 types of lymphocytes.
B Cells - a white blood cell that produces antibodies
helper T cells - signals the b cell to produce antibodies
Antibodies - special protein that helps fight infection

6. Communicable Diseases
IMMUNE SYSTEM
Soon after a pathogen enters the body, helper T cells signal the B cells to produce antibodies.
B cells enter the lymph system and travel in the blood to destroy the pathogen.
Antibodies can make pathogens ineffective and sensitive to macrophages. They attach to pathogens and make them easier for macrophages to destroy.
A macrophage is a white blood cell that surrounds and destroys pathogens.

7. Communicable Diseases
IMMUNE SYSTEM
Destroyed pathogens enter the lymph, are filtered in the lymph nodes and removed by the spleen

8. Communicable Disease IMMUNITY
The immune system helps people develop immunity.
Immunity - the body’s resistance to disease causing agents. There are 2 types.
Active immunity -
For example - you are exposed to the chickenpox virus. You get chickenpox. The body creates antibodies to overcome chickenpox. You get better. The antibodies remain in the body and protect it from the chickenpox virus.
You may also be protected from pathogens by a vaccine.

9. Communicable Diseases
IMMUNITY
When you receive a vaccine, dead or weakened pathogens are introduced into the body. The body makes antibodies for the specific pathogen introduced, protecting you from that pathogen.

10. Communicable Diseases
IMMUNITY
Passive immunity is immunity that results from introducing antibodies into a person’s bloodstream.
They can be from another person’s blood. This type of immunity is short-term and is used there is immediate risk.

11. Communicable Diseases
PATHOGENS
A germ that causes disease is called a pathogen. A pathogen that can be spread from one living thing to another is called a communicable disease. Most pathogens are parasites, organisms that live in or on another organism, depending on it for nourishment.
Types of pathogens:
Bacteria - single cell microorganisms
live almost anywhere, air, soil, water
found 7 miles into the ocean, 40 miles above the earth
reproduce rapidly by cell division under the right conditions

12. Communicable Disease

13. Communicable Diseases
IMMUNITY
Bacteria
some bacteria are “friendly” - live in the body and assist normal functions
lactobacilli - aid in digestion by producing lactic acid from simple carbohydrates
coliform - live in the intestine to break down disease causing bacteria and carbohydrates
Some are “unfriendly” - the produce toxins (poisons) that cause a disease to develop such as:
syphilis, gonorrhea, strep throat, tuberculosis, tetanus, diphtheria, Lyme disease

14. PATHOGENS
Viruses - smallest know infectious agent.
viruses and not living cells, but inner cores of genetic material in a protein shell
entirely dependent on living cells for survival and reproduction
invade all known forms of life
highly specific - attack only specific animal cells
enter the body, attaches to the host cell and copies itself using materials from the host cell. Process is repeated.
many viruses run their course and are destroyed by the immune system.

15. Communicable Diseases
Influenza Polio Virus

17. Communicable Disease PATHOGENS Viruses
no medicines yet will successfully treat viral diseases
Viruses cause:
common cold, mumps, hepatitis, mononucleosis, chickenpox. HIV, rabies, ebola, influenza

18. Communicable Diseases
PATHOGENS
Rickettsias - resemble bacteria but work like viruses
found in the intestinal tract if insects such as fleas and in mice, ticks and mites
passes to humans and animals through bites or feces deposited on the skin
Rickettsial diseases: typhus, Rocky Mountain spotted fever

19. Communicable Diseases
Rocky Mountain Spotted Fever

20. Communicable Diseases
PATHOGENS
Protozoans - single cell organisms, larger and more complex than bacteria
most common in tropical areas and places with poor sanitation
Diseases: Malaria, African sleeping sickness, dysentery

21. Communicable Diseases
PATHOGENS
Fungi - simple organisms that cannot make their own food
feed off dead plants and animals
like dark, damp environments
invade deep tissue of scalp, skin, nails
Fungal diseases:
ringworm, athlete’s foot, jock itch, nail infections, thrush

22. Communicable Diseases
PATHOGENS
Helminths - parasitic worms
infected through undercooked fish, pork or poor hygiene
Helminth diseases: digestive tract -- tapeworm, pinworm, hookworm
muscle and blood -- trichinosis

23. Communicable Diseases
HOW DISEASES ARE COMMUNICATED
People
Direct contact
shaking hands
intimate kissing
sexual intercourse
human bite
pregnant woman to child
body fluids
handling blood, urine, vomit
toughing open sores
blood transfusions

24. Communicable Diseases
TRANSMISSION
Indirect contact -
exhaled, sneezed or coughed droplets that are inhaled by others
common cold, flu, measles, chicken pox, tuberculosis

25. Communicable Diseases
TRANSMISSION
Contaminated Objects
eating and drinking utensils, toothbrushes, razors, combs, needles for tattooing or drugs, telephone, door knows, pens and pencils
Animal and Insects
blood sucking insects - malaria and encephalitis(mosquitoes) Lyme Disease(deer tick), tapeworm (rat fleas)
animal bites - rabies
birds, hamsters, undercooked food - salmonella and trichinosis
droppings - hanta virus, avian lung disease

26. Communicable Diseases
TRANSMISSION
Environment
food, water, soil
human negligence
improper disposal of toxic wastes, insecticides, herbicides
careless disposal of human wastes
air, water or soil pollution
improperly handled food

27. Communicable Diseases
PREVENTING TRANSMISSION
Carefully selection
no dented or bulging cans, open jars, or damaged wrappings
defrost your food in the recommended manner
cook you food to a safe internal temperature
keep hot foods hot and cold foods cold
no more than 2 hours at room temperature
keep refrigerator at 40 degrees or lower and freezer at 0
avoid cross contamination
wash cans before opening
use proper cleanup techniques

28. Communicable Diseases
STAGES OF INFECTIOUS DISEASE
AFTER EXPOSURE
Incubation
time of entry to time of first symptom
some may never show symptoms
may last 2 days to weeks
Prodromal Stage
early symptoms appear
time most likely to pass to others
illness or acute stage
fully developed symptoms
may pass to others

29. Communicable Disease STAGES OF INFECTIOUS DISEASE Recovery Stage
immune system or medication has stopped progression of the pathogen
begin to feel better
Relapse or convalescence stage
become ill again after partial recovery
dangerous stage because system is already weakened

30. Communicable Disease STAGES OF INFECTIOUS DISEASE Immunity
prevent getting the disease again
there is no immunity for some infectious diseases - STD’s

31. Communicable Disease CARE OF THE IMMUNE SYSTEM
Eat well balanced meals - do not skip meals
Practice good sleep hygiene
Practice good stress management techniques
Avoid unhealthful substances (alcohol, tobacco, etc.)
Do not share items that can transfer pathogens
Practice good personal hygiene
Keep your immunizations up to date.
What your hands
Cover coughs and sneezes
Stay home when you are sick