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Immune System Part 1:
Lymphatic Organs & Disease
Chapter 13 / 40-1
Overview
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I. Immune System Functions
II. Lymphatic Organs & Tissues
III. Immune Disorders
IV. Infectious Disease
V. Immune Defenses
VI. Immunity
I. Immune System
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Consists of a network of
lymphatic organs,
tissues, and cells
Plays an important role in
keeping us healthy
When homeostasis is
NOT in balance, the body
has disease
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Function
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Defends body against disease using
white blood cells to maintain
homeostasis
White blood cells are produced by
the lymphatic organs to fight
pathogens invading the body
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Pathogens are things that infect you
and make you sick
II. Lymphatic Organs
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1. Red Marrow
2. Thymus
3. Spleen
4. Lymph nodes &
vessels
5. Tonsils & Adenoids
6. Appendix &
Peyer’s patches
1. Red Bone Marrow
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Function: site of stem
cell production and
creation of white blood
cells.
In adults, red marrow is
found in long and flat
bones.
In children it is found in
most bones
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5 Types of White Blood Cells
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Neutrophil, eosinophil, basophil, monocyte,
lymphocyte (B lymphocyte & T lymphocyte)
2. Thymus
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Located below the sternum
Larger in children, shrinks
with age
Critical to immunity
Function: allows the body
to reject foreign tissues or
invading pathogens
Immature T-lymphocytes
(from red marrow) move to
the thymus where they
mature
3. Spleen
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Located on the left
side of the abdomen
Function: Filters blood
cells and destroys
worn out blood cells,
engulfs debris
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Can live with out the
spleen but more
susceptible to
infections
4. Lymph Nodes & Vessels
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Function: Lymph nodes filter
lymph
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Lymph– excess tissue fluid
carried by lymphatic vessels
Mostly made of water and
dissolved substances
(electrolytes, oxygen)
Lymph may contain white blood
cells, bacteria, viruses, cancer
cells and cell debris
4. Lymph Nodes & Vessels
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Nodes can become
swollen when
infected
Function: Lymph
vessels transport
lymph from tissues
and nodes back to
the heart
5. Tonsils & Adenoids
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Small masses of
lymphatic tissue around
the pharynx
Function: Trap and
remove pathogens and
other foreign materials
that enter the mouth or
nose
Adenoids, like the
thymus, shrink with age
6. Appendix & Peyer’s Patches
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Both are located in
intestinal wall
Function:
Encounter
pathogens that
enter the body
through the
intestinal tract.
III. Immune Disorders
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A. Allergies
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Tricks immune system
to have response
Response is harmful
rather than protective
because it attacks our
own cells
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Symptoms of allergic reaction
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Hives, itching, swelling
Tightness of chest, difficulty breathing
Swelling of tongue
Dizziness, drop in BP
Anaphylactic shock
Unconsciousness or cardiac arrest
B. Edema
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Localized
swelling due to
the accumulation
of lymph
Can lead to
tissue damage
and eventual
death if
untreated
C. Autoimmune Diseases
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The immune system does not distinguish
between self and non-self
The body produces white blood cells that
attack its own tissues
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Examples of autoimmune diseases
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Multiple sclerosis – white matter of
brain and spinal cord are destroyed
Juvenile diabetes – destroys pancreatic
beta cells that produce insulin
Rheumatoid arthritis – destroys joints
III. Infectious Disease
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Disrupts normal body function
(homeostasis)
Caused by a pathogen.
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Pathogen: anything that invades your
body & causes a disease
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Ex: bacteria, protozoan, fungi, viruses,
parasites, worms
It can be contagious (passed from
person to person)
A. Disease Transmission
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People may carry a disease without even
knowing it.
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Can be spread during the incubation period
(before symptoms occur)
Transmission by:
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1. Direct contact
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2. Indirect contact-through the air
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Kissing
coughing & sneezing
3. Contact with object
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sharing drinks, door knobs, desks
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4. Infected animals
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Vector transmits disease
Ex: mosquito
5. Contaminated food or water
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food poisoning
B. Agents of Disease
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1. Protists
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feed on nutrients in host’s
blood
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2. Worms
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parasitic flatworms & round
worms
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ex: tapeworms & hook worms
3. Fungi
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attack moist areas, like the skin,
scalp, mouth & throat
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ex: malaria, dysentery
ex: ringworms & athlete’s foot
4. Bacteria
See Next
Sections
4. Bacteria
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Bacteria
(prokaryotes) have a
cell wall, cell
membrane, genetic
material, and
ribosomes for protein
production
Bacteria do not have a
nucleus or organelles
Bacteria are living
cells
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They cause disease by:
 Releasing toxins that
are poisonous to
people
 Break down tissues of
infected organism for
food
Infectious forms of
bacteria Cholera, Bubonic
Plague, tuberculosis,
gonorrhea, anthrax,
streptococcus,
staphylococcus
Treatment: ANTIBIOTICS
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Antibiotic Resistance
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Currently, many bacteria are becoming resistant
to antibiotics
This is because of antibiotics being over
prescribed
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(often for viral infections, which they have no effect on)
MRSA – Methicillin-resistant Staphylococcus
areus
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Bacterial strain resistant to antibiotics
5. Virus
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Viruses are non-living, non-cellular
structures thousands of times
smaller than a cell
Structure: DNA surrounded by a
protein coat
Virus cannot reproduce itself
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Virus relies on a HOST cell to replicate
A virus usually tricks the host to
pull it into cell
Virus genetic material takes over
the host cell causing the cell to
make new viruses
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Common types of
human viruses:
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Influenza, chicken
pox, polio, HIV,
common cold, and
Herpes (cold sores)
Uncommon types of
human viruses:
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Ebola, West Nile
Virus, Dengue Fever,
Smallpox
HIV Virus
Prevention
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Vaccines PREVENT viral infection
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Person is injected with a weakened
virus.
The immune system can later
recognize the normal virus and fight it
off
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Ex: measles, mumps, rubella (MMR),
smallpox, polio, flu strains (swine flu)
Treatment
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Viral infections are fought by the
immune system or with anti-viral
drugs.
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Some viruses are too strong and too
fast for the immune system to fight.
These viruses lead to:
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Epidemics (over large areas)
Pandemics (over whole countries)
To treat mass outbreaks: contain the
area and quarantine the infected.
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Common Viruses
Influenza (Flu Virus)
Kills 30,000 Americans every
year
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Human Papilloma
Virus (HPV)
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Deadly Viruses
Ebola virus
Africa
~90% mortality rate
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SARS (Severe acute
respiratory syndrome)
China 2002-3
5328 cases, 349 deaths
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The Immune System Part 2:
Immune Defenses
Human Body Systems
Chapter 13/ 40-2
I. Immune System Overview
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Immune System: body’s defense
system against disease
2 Defense Systems for foreign
materials
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Nonspecific Defense System
Specific Defense System
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Includes White Blood Cells (WBCs) to fight
infection through inactivating foreign materials
or cells
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Soldiers of your defense system
A. Pathogens & Antigens
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Pathogens (things that infect you)
contain antigens
Antigens are like chemical markers
(name tag) that tell what the
pathogen is
HI, MY NAME IS
Swine Flu Virus
Antigen
Haha!
I am the pathogen.
I have invaded you!
B. WBCs & Antibodies
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WBCs can recognize the
antigens because they
have antibodies.
Antibodies are proteins
that recognize and bind
to the antigen because
they fit together
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Antibodies mark the
pathogen for destruction
Nooo!
Antibody
C. Types of WBCs
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Phagocytes - “eat” & destroy pathogens
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Macrophages, Neutrophils, Monocytes
Eosinophils – deal with parasitic infections
Basophils – involved in allergic reactions
Lymphocytes – deal with specific invaders
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B-lymphocytes- make antibodies
T-lymphocytes- cells- recognize & kill pathogen
Nooo!
II. Immune Divisions
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A. Nonspecific Defenses
B. Specific Defenses
C. Acquired Immunity
A. Nonspecific Defenses
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Body protects itself the SAME way
regardless of what is invading it
Protects against variety of invaders
Fast-acting Response
Lines of Defense
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1. Skin, Sweat, Mucus & Tears
2. Immune Response
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Fever, Macrophages, Inflammation
1. First Line of Defense
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Skin, sweat, mucus, and tears
Skin is a physical barrier to keep
pathogens out of the body
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Cuts or breaks in the skin allow
pathogens to enter
Sweat, mucus, & tears contain
lysosomes and other chemicals that
kill bacteria.
2. Second Line of Defense
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Immune response – pathogens are
recognized by antigens
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Fever – body raises temperature to
slow down growth & replication of
pathogen
Macrophages – WBCs designed to eat
pathogens
Inflammation – infected area swells
with lymph and blood bringing WBCs
and macrophages to fight pathogen
B. Specific Defenses
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Immune system attacks specific
pathogen
Pathogen can be recognized by its
specific antigen
Lymphocytes (B-cells & T-cells)
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B-cells- make antibodies & have memory
T-cells- recognize & kill pathogen
2 Types of Specific Defense
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1. Antibody Mediated Immunity
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Antibodies mark pathogens for destruction
Involves B cells
2. Cell Mediated Immunity
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Attacks infected self cells
Involves T cells
1. Antibody Mediated Immunity
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aka: Humoral Immunity
Antibodies produced by B cells mark
pathogen for destruction by
macrophages
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Primary Response:
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First time you encounter pathogen
3-6 days to launch immune attack
Helper T cells signal B cells to divide
and differentiate to produce:
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Plasma Cells – make antibodies
B memory Cells – remember antigen in
case of second infection
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Antibodies attach to antigens that
are outside a cell
Macrophages engulf anything
labeled with an antibody
Antibodies won’t allow viruses to
infect cells
Nooo!
Plasma
cell
Antibody
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2. Secondary Response
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You encounter the same antigen again
2-3 days to respond
B-memory cells respond faster to
make antibodies
I remember…
 Do not get sick
 Memory cells =
B-memory
IMMUNITY
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B. Cell Mediated Immunity
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Immune system attacks infected cells
T cells carry out cell mediated
immunity
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When viruses or pathogens get inside
cells, or when a cell turns cancerous,
antibodies alone cannot destroy them
Infected self cell displays antigens
from the pathogen on cell membrane
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T-cells divide and differentiate to
recognize and kill infected cell
1. Helper T-cells
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recognize antigen and recruit other cells
to fight invader
(general in command)
tell B-cells to make antibodies
 Attract Cytotoxic (Killer) T-cells
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2. Cytotoxic (Killer) T-cells
kill infected self-cell by injecting
toxic chemicals (perforin)
 (trained assassins)
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Hello,
I am a deadly
Killer T-cell
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3. Suppressor T cells
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Release chemicals to suppress the
activity of T & B-cells from overreacting or harming the body
4. Memory T cells
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Will cause secondary response if same
antigen invades again
Immune Cartoon
I am a deadly
Killer T-cell.
Die infected cell!
Haha!
I am the pathogen.
I have invaded you!
Infected
Self Cell
Killer T-cell
I have invaded
your cell!
Antigen
Cell-mediated
Immune Response
Suppressor
T-cell
I am the all-knowing
Helper-T cell. I recognize
the antigen.
Helper
T-cell
Nooo!
Antibodies
I have invaded
your tissues!
Antibody-mediated
Immune Response
Macrophage
Plasma cell
I remember…
B-cell
I will eat
invaders!!!
B-memory
The Immune Response Team
Haha!
I am the pathogen.
I have invaded you!
Hello,
I am a deadly
Killer T-cell.
Die infected cell!
Infected
cell
Antigen
I am the all-knowing
Helper-T cell. I recognize
the antigens.
Hey, Killer T,
destroy this infected cell
And B-cell,
make some antibodies.
Antibodies
Nooo!
I remember…
Helper
T-cell
B-cell
B-memory
Antibody
C. Acquired Immunity
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Immunity is acquired after exposure to
antigen and a memory B or T cell is made
2 Kinds
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1. Active Immunity: you make antibodies in
response to antigen
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Vaccine
Natural exposure to pathogen
2. Passive Immunity: you obtain antibodies
from another source
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Mother’s milk gives baby antibodies
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II. Immunodeficiency
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Production or function of immune cells
is abnormal
May be congenital or acquired
Includes AIDS (Acquired
Immunodeficiency Syndrome)
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1. AIDS
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HIV (Human Immunodeficiency Virus) is
a retrovirus (RNA for genetic material)
HIV targets Helper T cells
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T cell makes new HIV viruses
Causes slow death of T cells while making
more of the virus
When there are not enough T cells, the
body is left defenseless against invading
pathogens
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AIDS progression:
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Phase I: few weeks to a few years; flu
like symptoms, swollen lymph nodes,
chills, fever, fatigue, body aches. Virus
is multiplying, antibodies are made but
ineffective for complete virus removal
Phase II: within six months to 10 years;
opportunistic infections present,
Helper T cells affected, 5% may not
progress to next phase
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Phase III: Helper T cells fall below 200
per cubic millimeter of blood AND the
person has an opportunistic infection
or type of cancer.
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Person is now termed as having “AIDS”
AIDS is when people get sick and
ultimately die from diseases they would
normally fight off, but cannot due to a
weak immune system.
These diseases are called Opportunistic
infections.
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Tuberculosis, encephalitis, Kaposi’s sarcoma,
and non-Hodgkin’s lymphoma
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AIDS Pandemic
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More than 36 million infected with HIV
worldwide
Most infections in sub-Sahara of Africa
Increasing spread in Asia and India
Most often spread by heterosexual
contact outside U.S.