Download Chapter 1, Section 2

SPONGE
Communicable and
Chronic Disease - Day 1
1. What names can you think of
for microscopic things that
make people sick?
2. Name something that
protects you from getting
sick.
Communicable and Chronic
Diseases
Section 1
The Spread of
Disease
Types of Disease
• There are two main
types of disease:
• Noncommunicable
diseases are
diseases that people
are born with or are
caused by how
people live.
Muhammad Ali –
Parkinson’s Disease
Types of Disease
• Communicable diseases are infectious
diseases spread from one living thing to
another.
• Communicable diseases are spread by
pathogens.
Types of Disease
• Pathogens are
any microscopic
germ that causes
disease.
• Even Prions
(proteins that are
not technically
alive) can cause
infectious disease
in people and cows.
Types of Disease
• Viruses are the smallest
common pathogen. When a
virus enters a cell, it takes
over the cell and causes it to
make more viruses, which
spread to other cells.
• Bacteria are single-celled
organisms. A small
percentage of them cause
disease by releasing
poison into your body.
Types of Disease
• Fungi are single or multicelled organisms that eat
plant or animal tissue.
Fungi cause athletes’ foot
as well as a few other
diseases.
• Helminthes are parasitic
worms that infect a
person’s digestive tract
after uncooked pork or
fish has been eaten.
The Spread of Disease
• Pathogens can be spread in
many ways:
– Contact with an infected
person
– Through the air (like a cough)
– Contact with contaminated
objects (like a needle)
– Contact from an animal (like a
mosquito bite)
– Eating or drinking
contaminated food or water
The Immune System
• The immune system
removes harmful
organisms from the
blood and combats
pathogens.
• Nearly all pathogens
are kept out of your
body by your skin, but if
they do get in, the
immune system takes
over.
The Immune System
• Lymphocytes are white blood cells that
help the body fight pathogens.
• When a pathogen enters the body,
lymphocytes multiply in lymph tissue and
fight the infection. There are two types:
– B cells create antibodies that fight
pathogens.
– Helper T cells signal B cells to begin
fighting pathogens.
Immunity
• The immune system helps people
develop immunity.
– Active Immunity is resistance to
disease once the body has fought that
disease.
– For example, once you’ve had chicken
pox, antibodies that kill chicken pox stay
in your body for the rest of your life.
– A vaccine is a dead or weakened
pathogen that is put into your body.
Your immune system produces
antibodies to the pathogens and can
more easily fight off a stronger version
of the pathogen later in life.
Immunity
• Anther type of immunity,
called Passive
Immunity, is immunity
that results from injecting
antibodies into a person’s
bloodstream.
– Instead of making a
person immune to a
disease, this helps them
fight disease better with
the help of extra
antibodies.
Common Bacterial Diseases
• Strep throat is a bacterial infection of the
throat. If not treated, it can develop into
rheumatic fever, which damages heart
valves.
Common Bacterial Diseases
• Tuberculosis (TB) is a
bacterial infection of the
lungs that can be spread
through the air when an
infected person coughs.
• At its worst, the disease
causes tubercles to form
in the lungs, resulting in
bloody coughing, fever,
weight loss and even
death.
Common Bacterial Diseases
• Meningitis is a swelling of
the membranes around the
brain and the spinal chord
that can result in death.
• The disease is spread
through saliva, and is a
severe threat to college
students.
• Meningitis can also be
viral, but this form is less
harmful.
Common Bacterial Diseases
• Diphtheria spreads through coughs
and sneezes or from any object that
has infected saliva droplets on it.
• Infected people have a hard skin
form in their throat that can block
breathing. The skin can produce
toxins that badly damage organs
like the heart.
• Fewer people get diphtheria since
the DTaP Vaccine (diphtheria,
tetanus, pertussis) became
common.
Common Bacterial Diseases
Pertussis is becoming
more common. The
vaccine does not always
work, and the disease is
becoming resistant to
antibiotics.
• Pertussis is a very infectious
disease, most common to
people between the ages of
10-19.
• It causes a deep,
uncontrollable “whooping”
cough. Droplets that are
sprayed in the air spread the
disease.
• This disease used to kill
hundreds of thousands of
children in the U.S. before the
DTaP vaccine was created.
The Problem with Antibiotics
• When antibiotics were first introduced in
the 1940’s, they were considered a
miracle drug.
• They work by destroying the cell
membranes or nuclei of bacteria.
• Antibiotics come in many forms
including pills and soaps.
• However, Antibiotics should only be
used when a person is sick with a
dangerous bacterial disease. They do
not work on viruses.
The Problem with Antibiotics
• In recent decades, bacteria have
adapted to resist most
antibiotics.
• This is because people over-use
antibiotics (like soap), which
gives bacteria many chances to
adapt to these medicines.
• Also, many sick people stop
taking their antibiotics when they
start feeling better instead of
continuing to take them for the
entire prescription time.
Misusing
Antibiotics =
Breeding Super
Bacteria