Download Communicable Diseases

Communicable Diseases
Lesson 44
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.
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.
Communicable Diseases
1. The first line of defense - general or non-specific resistance.
a. Physical Barriers
i. Unbroken skin acts as a barrier to prevent pathogens from
entering the body.
ii. Tears, perspiration, saliva, and oils on skin kill many pathogens.
iii. Mucus and hairs that line the inside of the nose also trap and
destroy pathogens.
iv. Pathogens that are swallowed are destroyed by stomach acids.
v. Reflexes such as coughing, blinking and vomiting
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.
1. B Cells - a white blood cell that produces antibodies
2. helper T cells - signals the b cell to produce antibodies
Antibodies - special protein that helps fight infection
http://www.bing.com/videos/search?q=how+antibodies+work&FORM=VIRE7#a
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.
Communicable Diseases
IMMUNE SYSTEM
Destroyed pathogens enter the lymph, are filtered in the lymph nodes and
removed by the spleen
http://www.bing.com/videos/search?q=how+the+lymphatic+system+functions&
FORM=HDRSC3#view=detail&mid=6865CA0EF770A1B1C1946865CA0EF770
A1B1C194
Communicable Disease
IMMUNITY
The immune system helps people develop immunity.
Immunity - the body’s resistance to disease causing agents. There are 2 types.
1. 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.
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.
http://www.cdc.gov/vaccines/schedules/
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.
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:
1. Bacteria - single cell microorganisms
a. live almost anywhere, air, soil, water
b. found 7 miles into the ocean, 40 miles above the earth
c. reproduce rapidly by cell division under the right conditions
Communicable Disease
Communicable Diseases
IMMUNITY
Bacteria
d. some bacteria are “friendly” - live in the body and assist normal functions
i. lactobacilli - aid in digestion by producing lactic acid from simple
carbohydrates
ii. coliform - live in the intestine to break down disease causing bacteria
and carbohydrates
e. Some are “unfriendly” - the produce toxins (poisons) that cause a disease
to develop such as:
syphilis, gonorrhea, strep throat, tuberculosis, tetanus, diphtheria, Lyme
disease
PATHOGENS
2. Viruses - smallest know infectious agent.
a. viruses and not living cells, but inner cores of genetic material in a
protein shell
b. entirely dependent on living cells for survival and reproduction
c. invade all known forms of life
d. highly specific - attack only specific animal cells
e. enter the body, attaches to the host cell and copies itself using
materials from the host cell. Process is repeated.
f. many viruses run their course and are destroyed by the immune
system.
Communicable Diseases
Influenza
Polio Virus
Communicable Disease
PATHOGENS
Viruses
g. no medicines yet will successfully treat viral diseases
h. Viruses cause:
common cold, mumps, hepatitis, mononucleosis, chickenpox. HIV, rabies,
ebola, influenza
Communicable Diseases
PATHOGENS
3. Rickettsias - resemble bacteria but work like viruses
a. found in the intestinal tract if insects such as fleas and in mice, ticks
and mites
b. passes to humans and animals through bites or feces deposited on
the skin
c. Rickettsial diseases: typhus, Rocky Mountain spotted fever
http://www.nlm.nih.gov/medlineplus/ency/article/001382.htm
Communicable Diseases
Rocky Mountain Spotted Fever
Communicable Diseases
PATHOGENS
4. Protozoans - single cell organisms, larger and more complex than bacteria
a. most common in tropical areas and places with poor sanitation
b. Diseases: Malaria, African sleeping sickness, dysentery
http://education-portal.com/academy/lesson/dysentery-and-the-bacteriashigella-symptoms-causes.html#lesson
Communicable Diseases
PATHOGENS
5. Fungi - simple organisms that cannot make their own food
a. feed off dead plants and animals
b. like dark, damp environments
c. invade deep tissue of scalp, skin, nails
d. Fungal diseases:
ringworm, athlete’s foot, jock itch, nail infections, thrush
Communicable Diseases
PATHOGENS
6. Helminths - parasitic worms
a. infected through undercooked fish, pork or poor hygiene
b. Helminth diseases: digestive tract -- tapeworm, pinworm, hookworm
muscle and blood -- trichinosis
http://www.nytimes.com/1981/09/30/garden/eating-raw-fish-thedangers.html
Communicable Diseases
HOW DISEASES ARE COMMUNICATED
1. People
a. Direct contact
i. shaking hands
ii. intimate kissing
iii. sexual intercourse
iv. human bite
v. pregnant woman to child
vi. body fluids
1. handling blood, urine, vomit
2. toughing open sores
3. blood transfusions
Communicable Diseases
TRANSMISSION
2. Indirect contact a. exhaled, sneezed or coughed droplets that are inhaled by others
i. common cold, flu, measles, chicken pox, tuberculosis
http://www.cbsnews.com/news/gross-coughs-and-sneezes-form-travelingdisease-clouds/
Communicable Diseases
TRANSMISSION
3. Contaminated Objects
a. eating and drinking utensils, toothbrushes, razors, combs, needles for
tattooing or drugs, telephone, door knows, pens and pencils
3. Animal and Insects
a. blood sucking insects - malaria and encephalitis(mosquitoes) Lyme
Disease(deer tick), tapeworm (rat fleas)
b. animal bites - rabies
c. birds, hamsters, undercooked food - salmonella and trichinosis
d. droppings - hanta virus, avian lung disease
Communicable Diseases
TRANSMISSION
5. Environment
a. food, water, soil
b. human negligence
i. improper disposal of toxic wastes, insecticides, herbicides
ii. careless disposal of human wastes
iii. air, water or soil pollution
iv. improperly handled food
Communicable Diseases
PREVENTING TRANSMISSION
1. Carefully selection
a. no dented or bulging cans, open jars, or damaged wrappings
b. defrost your food in the recommended manner
c. cook you food to a safe internal temperature
d. keep hot foods hot and cold foods cold
e. no more than 2 hours at room temperature
f. keep refrigerator at 40 degrees or lower and freezer at 0
g. avoid cross contamination
h. wash cans before opening
i. use proper cleanup techniques
http://www.ag.ndsu.edu/pubs/yf/foods/fn582.pdf
Communicable Diseases
STAGES OF INFECTIOUS DISEASE
AFTER EXPOSURE
1. Incubation
a. time of entry to time of first symptom
b. some may never show symptoms
c. may last 2 days to weeks
2. Prodromal Stage
a. early symptoms appear
b. time most likely to pass to others
3. illness or acute stage
a. fully developed symptoms
b. may pass to others
Communicable Disease
STAGES OF INFECTIOUS DISEASE
4. Recovery Stage
a. immune system or medication has stopped progression of the
pathogen
b. begin to feel better
5. Relapse or convalescence stage
a. become ill again after partial recovery
b. dangerous stage because system is already weakened
Communicable Disease
STAGES OF INFECTIOUS DISEASE
6. Immunity
a. prevent getting the disease again
b. there is no immunity for some infectious diseases - STD’s
Communicable Disease
CARE OF THE IMMUNE SYSTEM
1. Eat well balanced meals - do not skip meals
2. Practice good sleep hygiene
3. Practice good stress management techniques
4. Avoid unhealthful substances (alcohol, tobacco, etc.)
5. Do not share items that can transfer pathogens
6. Practice good personal hygiene
7. Keep your immunizations up to date.
8. What your hands
9. Cover coughs and sneezes
10. Stay home when you are sick