Mr. Ramos
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Objectives:
◦ Discuss the ways in which pathogens can be spread
◦ Describe the immune system and how it responds
to pathogens
◦ List ways to keep the immune system healthy,
including getting adequate rest
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A germ, or pathogen, is something that causes disease.
Examples of pathogens include
bacteria, viruses, protozoa, and fungi.
Not all bacteria, viruses, protozoa, and
fungi are pathogens.
A communicable disease is an illness caused by a
pathogen that can be passed to a person from another
person, animal, or object.
◦ Examples: Common cold and the Flu
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Pathogens may be spread when an infected agent
comes into direct contact with a noninfected agent.
◦ Touching, kissing, sharing eating utensils, or exchanging bodily
fluids, as in sexual activity or needle sharing.
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Pathogens may also spread indirectly through
contact with doorknobs, tabletops, faucet handles,
and other surfaces.
Type of Pathogen
Description
Diseases
Bacteria
Bacteria are single-celled
microorganisms that live
nearly everywhere. When
disease-causing bacteria
enter a person’s body,
they rapidly reproduce.
Strep throat, Lyme
disease, and urinary tract
infections
Viruses
Viruses are the smallest
and simplest pathogens.
They are not living
organisms. However,
they can reproduce
inside living cells
Colds, chicken pox, small
pox, measles, herpes
Type of Pathogen
Description
Diseases
Protozoa
Protozoa are singlecelled organisms that
may capture other tiny
life forms for food. Some
protozoa can live within
the human body as
parasites.
Malaria, dysentery
Fungi
Fungi are single-celled or Athlete’s foot, ringworm,
muticelled organisms
nail fungal infections
that feed on organic
material. Yeasts and
molds are two types of
fungi that may cause
illness.
Type of Pathogen
Description
Diseases
Rickettsia
Rickettsia are a special
type of bacteria that
multiply like viruses.
Rickettsia species are
carried by many ticks,
fleas, and lice.
Typhus, Rocky Mountain
spotted fever
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The immune system is the body’s
defense against pathogens.
The immune system is made
up of cells, tissues, and organs.
The immune system has three
lines of defense:
◦ First line of defense
◦ Second line of defense
◦ Third line of defense
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The first line of defense:
◦ Skin – unbroken skin provides a barrier against
pathogens
◦ Mucous membrane – tissue that lines the nose, mouth,
and throat. Mucous is the sticky
◦ Tears – contain chemicals that destroy pathogens
◦ Saliva - contain chemicals that destroy pathogens
◦ Sweat - contain chemicals that destroy pathogens
◦ Stomach acid – destroys pathogens that
survive in the mouth & throat
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The second line of defense:
◦ If pathogens pass the first line of defense, the body
launches the second line of defense.
◦ This is a nonspecific immune response.
◦ Phagocytes are white blood cells that find,
engulf, and digest pathogens.
◦ Phagocytes release chemicals that cause inflammation:
redness, swelling, warmth, and pain.
◦ Phagocytes can raise the body
temperature (fever) to destroy pathogens.
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The third line of defense:
◦ This is a specific immune response that targets particular
invading pathogens.
◦ The body contains a clear liquid called lymph that helps
eliminate foreign substances.
◦ A lymphocyte is a white blood cell that serves as a building
block of the body’s immune system.
◦ B cells, T cells, and natural killer cells are examples of
lymphocytes.
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The third line of defense:
◦ B cells and T cells can recognize antigens.
◦ Antigens are substances that cause
an immune reaction to the body.
◦ When a B-cells detects an antigen,
it makes antibodies.
◦ An antibody is a protein in the blood that destroys or
disables a specific antigen.
◦ Memory cells help speed the production of antibodies by
recognizing antigens there were once present in the
body.
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Immunity is the body’s ability
to resist disease.
There are 4 types of immunity:
◦ Naturally acquired active immunity
◦ Artificially acquired active immunity
◦ Naturally acquired passive immunity
◦ Artificially acquired passive immunity
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Get regular physical examinations
and vaccinations.
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Visit a physician when you feel ill.
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Follow directions when taking
Rx and over-the-counter drugs.
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Reduce stress.
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Exercise regularly.
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Get 8 hours of sleep each night
Plan your meals according to
the Food Guide Pyramid.
Avoid the use of tobacco,
alcohol, and other drugs.
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Objectives:
◦ Discuss facts about communicable diseases and
society.
◦ Identify common communicable diseases and
describe their characteristics.
◦ Identify ways to prevent the spread of disease.
◦ Explain why you need to keep a personal health
record.
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Communicable disease are all
contagious, spread by direct or
indirect contact.
Lyme disease, for example, is a
bacterial disease transmitted through a tick.
◦ It can spread from tick to person, but not from person to
person.
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In the United States, sexually transmitted diseases, such
as syphilis, gonorrhea, and chlamydia are some of the
most common communicable diseases.
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Communicable diseases vary in their causes, symptoms,
duration, and diagnosis.
Treatment depends on the type of pathogen that causes the
disease.
An antibiotic is a substance that kills or slows the growth of
bacteria.
◦ Antibiotics do NOT work on viral infections.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
Cold
A cold is a viral
infection that
affects the
lining of the
upper
respiratory
tract
Scratchy or
sore throat,
stuffy or runny
nose,
sneezing,
cough,
headache, mild
fever, muscle
aches, loss of
appetite
7 to 14 days
In most cases,
people
diagnose
themselves
with a cold
because they
are familiar
with the
symptoms
Because colds
are caused by
viruses,
physicians
cannot
prescribe
antibiotics for
them. Overthe-counter
drugs can treat
some of the
symptoms,
such as
headache and
runny nose. A
person who
has a cold
should rest
and drink
fluids.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
Influenza
Influenza, also
known as “Flu,”
is a viral
infection of the
respiratory
tract.
High fever,
chills,
headache,
severe muscle
aches,
dizziness, loss
of appetite,
tiredness,
cough, nausea,
weakness,
depression.
5 days for
major
symptoms to
subside; 7 to
14 days for
health to
return.
Some people
diagnose
themselves
with the flu
according to
symptoms.
Others go to a
physician for a
laboratory test.
A person who
has the flu
should rest
and drink
fluids. A
nonaspirin
medicine will
help relieve
symptoms. A
flu shot can
reduce a
person’s
chances of
getting the
disease.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
West Nile virus
West Nile virus
is an infection
that is spread
by the bite of
an infected
mosquito.
Most cases
have no
symptoms.
However, mild
symptoms
include fever,
body aches,
and nausea.
Severe
symptoms,
which are rare,
include high
fever, tremors,
and vision loss.
A few days for
mild symptoms
and several
weeks for
severe
symptoms.
Physicians
diagnose West
Nile virus
based on
symptoms and
tests.
Mild cases pass
without
treatment.
Severe cases
require
hospital care.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
Mononucleosis
Epstein Barr
Virus
(a type of
Herpes Virus)
Tiredness,
fever, sore
throat, sore
muscles,
enlarged
spleen, loss of
appetite,
generalized
weakness,
nausea, severe
headache,
stiffness, chest
pain.
2 to 4 weeks
Physicians
diagnose
mononucleosis
based on
symptoms and
blood tests.
(The blood test
is called a
mono-spot
test)
A person who
has mono
should rest,
take
acetaminophen
or ibuprofen,
and avoid
rigorous
physical
activities for a
month or so
after recovery.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
Hepatitis (A, B,
C, etc)
Hepatitis is a
viral disease
that causes
serious
damage to the
liver. The 3
most common
forms of
hepatitis are
hepatitis A, B,
and C.
Fatigue, loss of
appetite,
nausea,
abdominal
pain, &
jaundice, or
yellowing of
the skin and
the whites of
the eyes.
People with
hepatitis A
recover in a
few weeks or
months.
Physicians
diagnose
hepatitis based
on symptoms
and laboratory
tests.
Type A: rest, a
healthful diet,
and plenty of
fluid.
Type A: contact
with the feces
of infected
people, &
contaminated
water, milk, &
food.
Types B & C:
Direct contact
with an
infected
person’s blood
or other body
fluids through
blood
transfusions,
sexual activity,
injecting
drugs, tattoos,
piercings, &
mother to child
transmission.
Type A: fever
and diarrhea
Type B: joint
pain
Type C: dark
urine
Some people
who have
hepatitis
experience no
symptoms.
About 90 to
95% of those
with hepatitis B
recover within
6 months.
About 75 to
85% of those
infected with
hepatitis C
have the
disease for the
rest of their
lives.
Type B:
Medications
can treat longlasting
infection.
Type C:
Physicians may
prescribe
medicines and
advise against
drinking
alcohol.
Vaccines can
prevent
hepatitis A and
B.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
Strep Throat
Strep Throat is
a bacterial
infection of the
throat caused
by
streptococcal
bacteria.
Painful throat
inflammation,
fever, chills,
body aches,
loss of
appetite, red
and swollen
tonsils, and
swollen glands.
3 to 5 days
with treatment
A rapid strep
test or a throat
culture
People with
strep throat
typically take
antibiotics,
such as
penicillin for a
course of 7
days.
Disease
Cause
Symptoms
Duration
Diagnosis
Treatment
Tuberculosis
Tuberculosis is
a bacterial
infection of the
lungs.
People with
tuberculosis
experience few
symptoms at
first. Later
symptoms
include fever,
weight loss,
fatigue, loss of
appetite, and
the coughing
up of blood.
A few months
with treatment
Skin tests and
chest X rays
are used to
diagnose
tuberculosis.
Three or four
oral
medications
are taken in
combination.
Severe cases
may require
hospitalization.
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Wash your hands for at least 20 seconds with soap and warm
water before & after preparing food, before eating, & after
using the bathroom. Use a nail brush daily to remove dirt
from under nails.
Keep your fingers away from your eyes, nose, & mouth.
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Cover your mouth and nose with a tissue when you cough or
sneeze. If you don’t have a tissue, cough or sneeze into your
elbow – not into your hand.
Do not share personal items, such as
toothbrushes or drinking glasses or bottles.
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Cover all sores or cuts with a bandage. Wash your hands with
soap and water if you touch your sore or cut.
Do not touch sores or cuts on another person’s body. Wear
disposable gloves if you are bandaging someone else’s
wound.
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Do not use illegal drugs. Injecting oneself with needles,
inhaling from shared pipes or cigarettes, and snorting drugs
lead to infections.
Practice abstinence from sex to prevent
the spread of certain diseases.
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Do not share needles to make tattoos
or pierce ears or other body parts.
Follow the tips to prevent foodborne illnesses.
Keep your food away from animals,
such as pets or insects. They might
spread pathogens to the food.
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Keeps pets well groomed, free of ticks
or fleas, and vaccinated.
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Use insect repellants when you are outside
in the spring, summer, and fall.
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Check with a physician if you
are bitten by an animal.