Disease and Immunity
Herpes
TB
Polio
Measles
Pathogens
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Any foreign invader that enters the body and causes
disease
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Pathogens include:
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Bacteria
Viruses
protists
A disease that can spread to others is called:
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Infectious
Contagious
communicable
The Body’s Reactions
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The first defense is our skin and mucous
membranes
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Sweat and oil is toxic to some bacteria
Mucus will trap invaders
Fever – an elevated body temperature will
suppress bacterial growth and speed up our
immune response
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Normal = 98.6 degree F / 37 degrees C
The Body’s Reactions
to a localized (small)
infection
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Inflammatory response
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Injured cells release chemical alarm signals
Capillaries respond by swelling and leaking fluid and
white blood cells
Swelled area is warm
White blood cells arrive to attack
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Pus in wounds is dead pathogens
Bacteria
Can be pathogenic
Characteristics of Bacteria
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How they eat
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Heterotrophic
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Autotrophic
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Eat other things
Make their own food like plants
Oxygen requirements
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Anaerobic
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Undergo fermentation (no oxygen)
Aerobic
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Use oxygen
Bacteria Classification
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1.
Two Kingdoms:
Eubacteria – most common
bacterial forms
1.
2.
All pathogenic bacteria
Archaebacteria – Most primitive
bacterial forms that live in
extreme environments
Kingdom Eubacteria
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Most common
3 basic shapes:
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Rod
Sphere
Spiral
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Prefix strep = Chains
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Prefix staphlo = Clusters
Gram staining
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Bacteria can also be classified by whether or not
they retain color when stained by a certain
chemical.
Whether or not they retain the color is based on
the components of their outer membrane
Gram-positive bacteria retain the color (violet)
Gram-negative bacteria do not retain the color
and are dyed with a secondary dye which turns
them pink.
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Different types of antibiotics are needed to treat
infections based on whether the bacteria is
Gram-negative or Gram-positive
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Some antibiotics kill bacteria by damaging their
peptidoglycan cell wall
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Which bacteria would be resistant to an antibiotic that
worked in this fashion?
Bacterial diseases
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Tetanus
Bubonic plague (The Black Death)
Bacterial pneumonia
Sinus infection
Strep throat
Tuberculosis (TB)
Antibiotics and Bacteria
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Antibiotics only work against bacteria!
Some antibiotics are made from chemicals that
bacteria and fungi produce naturally
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Penicillin is made is from a type of fungus
Other antibiotics have been created in medical
laboratories
Amoxicillin, Zithromax, Tetracycline,
Vancomycin
Antibiotic Resistant Bacteria
Remember evolution
1) Bacteria have different characteristics due
to mutations.
2) Some of these mutations help the
bacteria to survive an attack by antibiotics.
3) The stronger (more resistant) bacteria
survive and infect a new person (host).
Tuberculosis
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Certain types of this pathogenic bacteria
can no longer be treated by antibiotics
How can you help to
stop the spread of
antibiotic resistant
bacteria?
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Useful Bacteria
1.
2.
3.
Breakdown organic matter and recycle carbon
and nitrogen
Help with the production of food
Clean up environmental disasters
Intestinal Bacteria
Protists
Single or multicelled organisms that live in
water
Plant like or
animal like
Three representative protists
flagella
Euglena
eyespot
Pseudopod
“false foot”
paramecium
amoeba
cilia
Protist (protozoan) disease
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Malaria
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Anopheles mosquito
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plasmodium
African Sleeping sickness
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Tsetse fly
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Trypanosoma
African Sleeping Sickness
The Common Cold
Viruses
A paothgen that is unable
to grow or reproduce
outside of a host cell.
It is considered non-living
Virology is the study of viruses
Virus Structure
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Viruses are extremely small Capsid/
They have a :
 Nucleic acid (DNA or RNA)
 Capsid - A protein coat
that protects the virus
 Protein tail -used to infect
host
Structure of Influenza Virus
Glycoprotein
Used to attach to
host cell
RNA
Capsid
Protein
Protein
Envelope
Adenovirus
Common cold
Common cold
Flavivirus
Hepatitis C (non-A, non-B)
Yellow fever
Hepatitis
Hepatitis, hemorrhage
Hepadnavirus
Hepatitis B virus (HBV)
Hepatitis, liver carcinoma
Epstein-Barr virus (EBV)
Herpes simplex type 1
Herpes simplex type 2
Human herpesvirus 8 (HHV8)
Mononucleosis, nasopharyngeal
carcinoma
Cold sores
Genital lesions
Chicken pox, shingles
Papovavirus
Human papillomavirus (HPV)
Warts, cervical carcinoma
Paramyxovirus
Measles
Mumps
Parainfluenza
Measles
Mumps
Common cold, ear infections
Poxvirus
Orthopoxvirus
Smallpox (eradicated)
Retrovirus
Human immunodeficiency virus
(HIV)
Human T-cell leukemia virus
(HTLV-I)
Acquired immunodeficiency
syndrome (AIDS)
Adult T-cell leukemia, lymphoma,
neurologic disease
Rhabdovirus
Rabies
Rabies
Herpesvirus
Viruses and Their Hosts
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When a virus meets a host cell, it can insert its
genetic material into its host, taking over the
host's functions
 The infected cell stops producing its own
proteins and starts to make new viruses!
Basically, it hijacks the cell!
Viral Phases
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Lysogenic phase - viruses are dormant
inside host cells for long periods.
 The host is not sick.
Lytic phase - The virus is stimulated
 new viruses are formed, self-assemble,
and burst out of the host cell, killing the
cell and going on to infect other cells.
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The host is now sick with a viral infection
Viral Mutations
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Viruses are able to rapidly mutate
Flu
HIV
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Attacks white blood cells – the cells that protect our
bodies from germs and infections
HIV is latent until another infection triggers the lytic
stage
Kills white blood cells
HIV has a high rate of replication and mutation which
has made it difficult to make a vaccine
Two Ways to Control
Viruses
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Vaccination – An injection of a harmless version
of a virus which causes an immune response.
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The body begins to produces antibodies against
that virus
Antiviral Drugs – Drugs that slow down or stop
a viral infection
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Tamiflu
Acquired Immunity – An immunity
that develops after exposure
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2 kinds:
 Active Immunity – When your body makes its own
antibodies
Getting sick
 vaccines
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Passive Immunity –
 Antibodies are given to the person
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Mother’s milk
White Blood Cells (WBC)
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These are your immune cells
Most are made in your bone marrow
There are many types
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Lymphocytes
Leucocytes
Neutrophils
B cells, T cells
WBC that you need to know
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T cells
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Killer cells
Made in bone marrow
Attacks a specific
pathogen
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B cells
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Made in bone marrow
Attack a specific
pathogen by making
antibodies
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They stick to the
surface of a pathogen
and so it cannot infect
any other cells
Memory Cells
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T cells and B cells that remain in the body after
an infection has been destroyed.
They provide the body with active immunity in
the future against that disease
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Your body made memory cells against chicken pox
when you had it as a kid. You now have life long
immunity to chicken pox!
Why can’t we get life long immunity to the flu or a
cold?