Download Infectious disease

CHAPTER 15
NOVEMBER 4 & 5, 2010
MEET THE MICROBES
•

•

•
•
•
•
•







TWO types of Microbes: Bacteria & Viruses
-Bacteria:
Can grow and multiply best in environments like: the human body,
warm, dark, moist, and nutrient-rich places. They do best in wounds,
where medicines can’t reach them. Ordinary soap makes bacteria
slippery so it is easy to wash off with water.
-Tetanus:
Type of bacterium likely to invade a puncture.
Disease is serious & often fatal, even when a person receives medical
attention.
Produces a poison that causes uncontrollable muscle contractions.
Tetanus kills a person if it reaches the lungs and heart muscles.
Tetanus shots provide immunity against the tetanus poison.
Example: Stepping on a nail.
Tuberculosis: infects a new person every second of every day and kills
millions each year.
Particular worry are new drug-resistant strains that fail to respond to
even the most powerful antibiotics. If patients repeats the mistake of
cutting the antibiotics therapy short, the result is a strain of TB
against which two antibiotics are useless.
If passed to others the microbes gather more and more resistance.
-Lyme Disease:
Passed on by ticks that live on wild deer
Starts out as red dot on the skin-weeks to months later you could feel
flulike symptoms; can cause chronic arthritis if left untreated.
MICROBES
CONTINUED….

•
•
•
•
•


-Viruses:
much smaller
mainly bits of a genetic material that can invade living cellseven bacterial cells. Using cells equipment viruses reproduce
themselves astonishing speeds. Viruses take over the cell’s
genetic machinery and force it to serve their purposes-to
reproduce more viruses.
Harm living cells so they cause diseases.
Most people suffer @ least 1 cold (upper respiratory
infection) a year and some come down with the flu
(influenza)-highly contagious. Viruses can be to blame.
Example of reoccurrence of viruses: Chicken pox----Shingles
-Other Pathogens:
Fungi (yeasts, molds)-athletes foot; Protozoa-single celled
creatures that cause diarrhea & other illnesses; Pinworms
(infect intestines of young children) and head lice are also
common and easily cured.
END OF 1ST SECTION QUIZ!
•True/False?
1. PATHOGENS ARE
MICROBES THAT CAUSE
INFECTIOUS DISEASE.
2. BACTERIA
AND VIRUSES
ARE NOT MICROBES.
3. MANY KINDS OF BACTERIA
ARE HARMLESS OR EVEN
BENEFICIAL.
4. CERTAIN KINDS OF VIRUSES
HAVE BENEFICIAL FUNCTIONS.
5. BACTERIA CAUSE TETANUS,
LYME DISEASE, AND
TUBERCULOSIS (TB).
True
False
True
False
True
6. FUNGI, PROTOZOA,
WORMS AND
True
OTHER KINDS OF PARASITES CAN ALSO
CAUSE ILLNESS.
7. THANKS TO MODERN MEDICINE,
TUBERCULOSIS IS NO LONGER A
LIFE-THREATENING DISEASE.
False
8. MANY DISEASES, SUCH AS
TUBERCULOSIS, MALARIA, PNEUMONIA,
AND MANY SEXUALLY TRANSMITTED
DISEASES, ARE BECOMING INCREASINGLY
DRUG RESISTANT.
9. VIRUSES CAUSE
DISEASE BY TAKING
OVER NORMAL CELLS.
10. FUNGI AND MOLDS ARE
VIRUSES.
True
False
True
PUBLIC DEFENSES AGAINST INFECTIOUS
DISEASES
How diseases spread:
-Look at it as a cycle; infected person (the host)
contaminates the air, food, or objects, near
another, who breathes the air or eats the food or
handles the objects and transfers the pathogen to
his or her body. Chances are that once inside the
pathogen and multiply in the body of the new
host, causing diseases.
Example: hepatitis: liver disease; caused by several
types of viruses transmitted by infected needs
(drug use, tattoos, blood transfusions), by eating
raw seafood from contaminated water, and by
any contact with body secretions from infected
people.

PUBLIC PROGRAMS AGAINST
PATHOGENS






Public sanitation measures provide some protection
against infections.
Government agencies chlorinate public water supplies
and treat sewage to kill pathogens that could
contaminate drinking water.
Cholera: dangerous bacterial infection causing violent
muscle cramps, severe vomiting and diarrhea, severe
water loss, and death. Where there is poor sanitation
sick people can pass on diseases.
If you travel to other countries you need to take
precautions when drinking the water. Just in case
boil water for at least 5 minutes.
Disinfectants: chemicals that kill microbes on
surfaces. Bleach is a disinfectant.
Antiseptics: prevent bacterial growth on body
surfaces and wounds.
IMMUNIZATIONS
Health programs control viral diseases by
destroying animal and insect carries of viruses,
and by immunizing house hold pets.
 Example: Rabies: a viral disease of the CNS that
causes paralysis and death. Health departments
require pets be immunized and that infected
animals be destroyed.
 Vaccine: drug made from altered microbes or
their poisons injected or given by mouth to
produce immunity. This was made to prevent
illnesses in people; this trains the body’s immune
system to recognize the active disease agent
when it invades. Example: Flu shot.

STATUS OF INFECTIOUS DISEASES




Constantly changing
U.S. Public Health Service is working its hardest to
control the following infectious diseases; tuberculosis;
hepatitis; pneumonia; polio; measles, rubella;
mumps; AIDS and hospital infections.
Smallpox: severe viral infection with skin eruptions;
once often fatal, it is now believed to be wiped out
world wide, thanks to immunizations.
Bubonic plague: bacterial infection causing swollen
lymph glands and pneumonia, frequently fatal.
Spread by rats in ancient days, has not been wiped
out completely.
END OF SECTION 2 QUIZ!
1. THE IMMUNE SYSTEM PROVIDES AN
IMPORTANT BARRIER AGAINST
INFECTION AND DISEASE.
2. A PERSON WHO HAS BEEN
INFECTED WITH A VIRUS OR
BACTERIA IS CALLED A HOST?
False
True
3. THE CYCLE OF AN EPIDEMIC CAN
OFTEN BE STOPPED BY IDENTIFYING
THE HOST OF A VIRUS.
4. PUBLIC SANITATION MEASURES
PROVIDE NO PROTECTION AGAINST
INFECTIOUS DISEASES.
5. CHLORINATED WATER IS
AN EXAMPLE OF A PUBLIC
SANITATION MEASURE.
True
True
False
6. CHOLERA IS A DISEASE SPREAD
THROUGH
MEAT? COUNTRIES
•TRAVELERSRAW
IN FOREIGN
False
SHOULD TAKE PRECAUTIONS AGAINST
COMMON LOCAL INFECTIONS, FOR
EXAMPLE, BY BOILING DRINKING WATER
True
AND RECEIVING IMMUNIZATIONS.
8. DISINFECTANTS AND ANTISEPTICS True
PREVENT BACTERIAL GROWTH.
9. SOAP AND WATER HAVE NO EFFECT IN
Fals
PREVENTING BACTERIAL INFECTION.
e
10. IMMUNIZATIONS ARE GIVEN THROUGH
THE INJECTION OF A VACCINE.
True
THE BODY’S DEFENSES & INFECTIOUS
DISEASES…
Barriers to Diseases:
 Skin
 The Body’s Membranes
 Components of the Immune System
 How the Immune System Fights Back
 Immunity

SKIN AND THE BODY’S MEMBRANES….




-





Designed to protect the body
Produces salty, acidic sweat secretions (most microbes don’t
like salt or acid).
Pores that let things out and won’t let microbes in.
Scientists found a natural antibiotic protein made skin that
kills microbes.
Punches holes in the bacterial cells causing them to leak.
Membranes are also barriers to pathogens; they line the body’s
chambers.
More defenses then skin
Has a layer of mucus that traps microbes, cilia (hair like
structures) that sweep them out; cells and chemicals of the
immune system that destroy them.
Internal membranes fend off great numbers of pathogens
every day.
Together the skin and body membranes work to defend
against the invading diseases.
COMPONENTS OF THE IMMUNE
SYSTEM….
Immune system acts as your own personal bodyguard-it
fights off invaders every day to keep you healthy.
 No specific location of where your immune system is at in
the body.
 Bone marrow is an important part of the immune system
-Grows white cells called lymphocytes.
 Thymus gland another important part-incubates some of
the lymphocytes and changes them into T-cells.
 T cells recognize the ‘enemy’.
 B cells-also from lymphocytes-which make antibodies
 Antibodies: large molecules that serve as the ammunition
to kill off invaders.
 Antigens: invaders; foreign substance body doesn’t
recognize.

HOW IMMUNE SYSTEM FIGHTS BACK….
Lymphocytes travel in your body fluids.
 During infection, lymphocytes are drawn to the lymph
nodes and make them swell.
 When you have a sore throat you can feel the lima bean
shaped lymph nodes that swell up when you are getting a
cold.
 Histamine: chemical produced by lymphocytes
-inflames the site of attack and attracts defenders.
-Antihistamine: works by reversing histamines effects
Ex. when allergies are bad you would use this type of
medication. Histamines would cause discomfort because
you are already inflamed.
 If an enemy is spot the T cells sends out an alert-your B
cells respond by making antibodies to destroy the invader.
There are other antibodies we call scavenger cells that will
eat the rest of the invader. Memory cells will ‘remember’
the invader for next time so it will be quickly destroyed.

IMMUNITY….
After the action is over with, only a few memory
and antibodies remain.
 Memory cells live for many years-responsible for
the immunity that follows many infections or
immunizations.
 Why don’t people develop immunity to the flu,
colds, or cold sores?

RECOGNIZING
Page 408…Figure 15-2
 Antibiotics: drugs that prevent bacterial growth.
-a person who has developed a bacterial infection can
often assist the immune systems defenses by taking
antibiotics
-useless against viruses because antibiotics are not
cells.
 Fever
-think twice before reaching for fever relief meds
Why?
-could actually assist in fighting off infection in your
body.
-Fevers help activate the immune system.

END OF SECTION 3 QUIZ!
•THE SKIN TAKES AN ACTIVE PART IN
True
FIGHTING OFF INFECTION AND DISEASES BY
RELEASING SALTY, ACIDIC SECRETIONS.
•THERE IS A NATURAL ANTIBIOTIC PROTEIN
MADE BY THE SKIN, WHICH KILLS BACTERIA
CELLS
BY PUNCHING
HOLES INHAVE
THEM.
•THE BODY
’S MEMBRANES
Tru
e
NO DEFENSES AGAINST
Fals
PATHOGENS.
e
•MUCUS, CILIA, AND CHEMICALS ALL WORK
IN THE BODY'S MEMBRANES TO DESTROY
INVADING
PATHOGENS
•THE BODY
’S IMMUNE. SYSTEM IS
LOCATED IN THE LOWER CORTEX OF
THE BRAIN.
Tru
e
False
•THE BONE MARROW PRODUCES
Tru
LYMPHOCYTES.
e
•T CELLS, LYMPHOCYTES WHICH HAVE PASSED
WHITE BLOOD CELLS CALLED
THROUGH THE THYMUS GLAND, PRODUCE
ANTIBODIES.
•ANTIBODIES DESTROY
INVADERS TO
THE BODY KNOWN AS ANTIGENS.
Tru
e
Fals
e
•THE HUMAN IMMUNE SYSTEM INCLUDES ‘MEMORY
CELLS’ THAT REMEMBER THE HISTORY OF AN
INFECTION AND ARE RESPONSIBLE FOR IMMUNITY.
True
•ANTIBIOTICS ARE AN EFFECTIVE
FORM OF TREATMENT FOR VIRAL
INFECTIONS.
False
TAKING ACTION……
 What
are some ways you can take
action to prevent infectious disease?
TAKING ACTION…
Keep immunizations up to date.
 Take care of your immune system
 Balanced diet
 Alcohol & other drugs are toxic to immune
system, weakening resistance.
 Less stress

AIRBORNE INFECTIONS
Prevent viruses being spread through the air by
uncovered cough or sneeze.
-Don’t sneeze directly into hand either; inside part
of elbow or even shirt.
 Try and stay away from people coughing or
sneezing carelessly in public places.
 If a loved one is sick try to give soothing words
from across the room; not giving hugs or kisses.

FOOD POISONING…..
If you have abdominal cramps, headache,
vomiting, diarrhea, and a fever you could have
food poisoning.
 Pathogens that grow in foods can make people
sick in two ways; infecting them or poisoning
them.
 Salmonella: bacterium infect the digestive tract;
causing the above symptoms. This illness can be
fatal if not treated.
 Botulism: often fatal condition with the botulin
toxin. This toxin affects the nervous system and
needs to be treated by a doctor immediately.
This usually comes from canned foods.

PREVENTION…

1.
2.
3.

Insist that food you eat be prepared according to 3
simple rules:
Keep hot food hot; if foods have been standing at
room temperature for a long time they are probably
spoiled.
Keep cold food cold; 2hrs or more is too long for cold
foods to sit out.
Eat only foods that have been prepared and served
on clean surfaces and clean hands. Avoid foods
served with utensils that previously touched raw
meats or are dirty from others.
Toss out any foods that have reached their
expiration date; if cans are bulging or appear to be
leaking.
END OF SECTION 4 QUIZ!
•IMMUNIZATION IS A VITAL STEP
IN PREVENTING MANY DISEASES
AND
INFECTION
.
•A
BALANCED
DIET
STRENGTHENS THE IMMUNE
SYSTEM.
•ALCOHOL HAS NO EFFECT ON
THE IMMUNE SYSTEM.
True
True
False
•PHYSICAL ACTIVITY BOOSTS THE
IMMUNE SYSTEM.
True
•STRESS STIMULATES THE
IMMUNE SYSTEM AND HELPS TO
PREVENT INFECTION.
False
•YOU CAN MINIMIZE THE RISK OF AIRBORNE
True
INFECTION BY DISTANCING YOURSELF FROM A
COUGHING OR SNEEZING PERSON.
•FREQUENTLY WASHING YOUR HANDS IS
ANOTHER WAY TO MINIMIZE THE RISK OF
INFECTION.
True
•FOOD POISONING IS AN UNLIKELY CAUSE OF
INTESTINAL DISTRESS.
False
•PATHOGENS HIDING IN FOOD CAN CAUSE
ILLNESS BY INFECTING THE DIGESTIVE TRACT
OF BY POISONING THE FOOD ITSELF.
True
•SPOILED FOOD IS ALWAYS REVEALED BY
AN ODD TASTE AND SMELL.
False