Human Immunodeficiency Virus
Acquired Immunodeficiency Syndrome
OBJECTIVES
At the end of this learning module, the student will be
able to:
Describe the etiology, incidence, symptoms, diagnosis,
and treatment for HIV and AIDS
Group Project
Students will work in groups of 2-3 and develop a trifold
handout that will explain and educate the targeted
population of young adults on the following:
 list the signs and symptoms of the three stages of HIV
 discuss ways that transmission does and does not take
place
 define the difference between HIV and AIDS
 raise the awareness of those with HIV and AIDS so as to
prevent them from being shunned or feared in society
Test Your Knowledge
1. What
is the difference between HIV and AIDS?
a. HIV is a virus and AIDS is a bacterial disease
b. There is no difference between HIV and AIDS
c. HIV is the virus that causes AIDS
Answer: C. HIV is the virus that causes AIDS. A person can live a relatively normal life for many years if
they are diagnosed with HIV, but they are said to have AIDS when they develop an HIV related
illness.
2. Is there a cure for AIDS?
a. Yes
b. NO
Answer: b. There is no cure for AIDS
3. Approximately how many people are living with AIDS worldwide?
a. 33 million
b. 23 million
c. 13 million
Answer: 33 million at the end of 2007. The majority were in sub-Saharan Africa
Avert,(2009)
5. Can you get AIDS from sharing the cup of someone with HIV?
a. Yes
b. No
c. Only if you don’t wash the cup
Answer: It is not possible to become infected with HIV from everyday casual contact such as
sharing food, shaking hands, or touching the same objects.
6. Can Insects transmit HIV?
a. Yes
b. No
c. Only mosquitoes
Answer: b. Insects cannot transmit HIV
7. HIV can make a person ill because….
a. It makes a person lose weight very suddenly
b. It reduces the body’s core temperature
c. It attacks the immune system
Answer: HIV affects a person’s immune system which makes them more vulnerable to infections
Avert (2009).
What is HIV?
 HIV stands for human immunodeficiency virus, which attacks the body’s
immune system.
 HIV is a blood-borne pathogen
 HIV depletes a portion of the immune system (Th cells), making individuals
extremely susceptible to life-threatening infections and malignancies
Our immune system has no protection against HIV
Mallory, W.W. (2009). Know the facts about HIV/AIDS. National Network for Family Resistency.
McCance & Huether (2006) page 278
What is AIDS?
AIDS, which stands for acquired immunodeficiency syndrome, is caused by HIV.
AIDS develops when the immune system can no longer protect itself from lifethreatening diseases.
If you have less than 200 CD4+ cells or if your CD4 percentage is less than 14%,
you have AIDS.
There is no cure for AIDS
Mallory, W.W. (2009). Know the facts about HIV/AIDS. National Network for Family Resistency.
HIV PREVALENCE ESTIMATE
Prevalence is the number of people living with HIV
infection at the end of a given year.
At the end of 2006, an estimated 1,106,400 persons in the
United States were living with HIV infection, with 21%
undiagnosed.
CDC. (2006). HIV Prevalence Estimates- United States.
HIV INCIDENCE RATE
 Incidence is the number of new HIV infections that occur
during a given year.
 In 2008, CDC estimated that approximately 56,300 people
were newly infected with HIV in 2006 (the most recent
year that data are available). Over half (53%) of these new
infections occurred in gay and bisexual men.
Black/African American men and women were also
strongly affected and were estimated to have an incidence
rate than was 7 times as high as the incidence rate among
whites.
CDC. (2006). HIV Prevalence Estimates- United States.
AIDS CASES
 In 2007, the estimated number of persons diagnosed with
AIDS in the United States and dependent areas was
37,041. Of these, 35,962 were diagnosed in the 50 states
and the District of Columbia and 812 were diagnosed in
the dependent areas. In the 50 states and the District of
Columbia, adult and adolescent AIDS cases totaled 35,934
with 26,355 cases in males and 9,579 cases in females,
and 28 cases estimated in children under age 13 years.
CDC. (2006). HIV Prevalence Estimates- United States.
Two million people died from AIDS in 2007 (5,500 people
per day), and 72 percent of these deaths were in subSaharan Africa.
Untl There’s a Cure Foundation 2009
Illustration: GfK
GeoMarketing
Epidemiology
 Routes of transmission: blood or blood products
IV drug abuse
Heterosexual & Homosexual
activity
Maternal-child transmission
before or during childbirth
 Predominant means of transmission is heterosexual
contact
Click to watch immunity video
http://www.virtualmedicalcentre.com/humanatlas1/vmc
_white.asp?anid=0002
Virtualmedicalcenter.com
Meet the wily HIV
virus
Viruses are simple
microorganisms consisting of
nucleic acid protected from the
environment by a layer of
proteins. Viruses have surface
molecules that act as receptors
for molecules found on the
surface of target cells. The
specificity of the receptors helps
viruses infect selected target
cells which determines the
symptoms of that particular
infection. A virus will attach to
the target cell, insert its genome
into the cell, utilize the cell’s
protein synthesizing capacity to
translate viral proteins, replicate
these proteins, and release them
from the cell to infect other
cells.
Pathogenesis
HIV is a type of virus called
retrovirus, which carries genetic
information in the form of RNA
rather than DNA. Retroviruses use a
viral enzyme, reverse transcriptase, to
convert RNA into double-stranded
DNA. Using a second viral enzyme,
an integrase, the new DNA is inserted
into the infected cell’s genetic
material where it may remain
dormant, and can remain latent for
years. However, if the cell is
activated, translation of the viral
information may be initiated,
resulting in the formation of new
virions, lysis and death of the
infected cell, and shedding of
infectious HIV particles.
McCance & Huether (2006). Pages 280-1.
Picture: The Body (2009). The Complete HIV?AIDS
Resourse
HIV Infection
The main type of cell that HIV infects is
the T helper lymphocyte. These cells
play a crucial role in the immune system,
by coordinating the actions of other
immune system cells. A large reduction
in the number of T helper cells seriously
weakens the immune system.
Avert (2009) The Different Stages of HIV Infection.
HIV infects the T helper cell because it has the
protein CD4 on its surface, which HIV uses to
attach itself to the cell before gaining entry. This is
why the T helper cell is sometimes referred to as a
CD4+ lymphocyte. Once it has found its way into a
cell, HIV produces new copies of itself, which can
then go on to infect other cells
Avert (2009) The Different Stages of HIV Infection.
HIV AND LYMPHOCYTES
Over time, HIV
infection leads to a
severe reduction in
the number of T
helper cells
available to help
fight disease. The
process usually
takes several years.
Avert (2009) The Different Stages of HIV Infection.
Mature HIV viruses (above) and the
lymphocyte from which they
emerged (below). Two immature
viruses can be seen budding on the
surface of the lymphocyte (right of
center).
Image: Science Clarified (2009)
What is CD4?
 CD4 cells are a type of lymphocyte (white blood cell). They
are an important part of the immune system. CD4 cells are
sometimes called T-cells. There are two main types of CD4
cells. T-4 cells, also called CD4+, are "helper" cells. They lead
the attack against infections.
 When someone is infected with HIV for a long time, the
number of CD4 cells they have (their CD4 cell count) goes
down. This is a sign that the immune system is being
weakened. The lower the CD4 cell count, the more likely the
person will get sick.
The Body. (2009). Fact Sheet 129
T-8 cells (CD8+) are "suppressor" cells that end the
immune response. CD8 cells can also be "killer" cells
that kill cancer cells and cells infected with a virus.
Researchers can tell these cells apart by specific
proteins on the cell surface. A T-4 cell is a T-cell with
CD4 molecules on its surface. This type of T-cell is
also called "CD4 positive," or CD4.
The Body (2009). Fact Sheet 129
 The CD4 cell count is a key measure of the health of
the immune system. The lower the count, the greater
damage HIV has done. Anyone who has less than 200
CD4 cells, or a CD4 percentage less than 14%, is
considered to have AIDS
 CD4 counts are used together with the viral load to
estimate how long someone will stay healthy.
 CD4 counts are also used to indicate when to start
certain types of drug therapy
The Body (2009). Fact Sheet 129
HIV
The primary surface
receptor on HIV is the
envelope protein gp120,
which binds to the
molecule CD4, found
primarily on the surface of
helper T cells. Other coreceptors on the target cells
are the chemokine
receptors CXCR4 and
CCR5. Different strains of
HIV1 are selective for the
CXCR4 or CXCR5 coreceptors.
McCance & Huether (2006). Page 282
Image : Kortright, (2008)
Primary cellular targets for HIV
•CD4-positive Th cells
•Dendritic cells
•Macrophages
•CD8-positive Tcells
•Double-positive thymic cells
•NK cells
•Neural cells
McCance & Huether (2006). Page 282
PRIMARY SITES OF INFECTION
Primary sites of infection are usually the
lymphoid areas of the mucosal surfaces.
Dendritic cells and mucosal T cells spread the
infection to other lymphoid organs in the
lymph nodes.
McCance & Huether (2006). Page 282
EARLY PHASE
At the time of diagnosis, the patient may manifest one of
several different conditions:
Serologically negative (no detectable antibody)
Serologically positive (positive for antibody against HIV
–but asymptomatic)
Early stages of HIV or AIDS
PHASES OF THE DISEASE
 During the initial phase antibodies against HIV-1 are not yet
detectable (window period), but viral products, including p24
antigen,viral RNA, and infectious virus, may be detectable in
the blood a few weeks after infection, and not detected by
routine essays.
 During the latent phase antibody levels against p24 and other
viral proteins, as well as HIV-specific CTLs, generally
increase, then remain constant until the development of AIDS.
 As the immune system becomes severely depressed, excess
viral antigen is released into the blood, and measuraable
antibody levels decrease.
McCance & Huether (2006). Pages 284
CLINICAL MANIFESTATIONS
 Within weeks after infection the virus aggressively infects and spreads, depleting CD4+ cells
causing HIV related diseases, such as:
Protozoal and helminthic infections
Fungal Infections
Bacterial Infections
Viral Infections
Neoplasms
 Patients with the early stages of HIV usually present with relatively mild symptoms
resembling influenza, such as night sweats, swollen lymph nodes, diarrhea, or fatigue.
 This early stage may last as long as 10 years.
 During this time, the disease is actively proliferating in lymph nodes.
McCance & Huether (2006). Pages 284-5
Answers.com (2009)
Answers.com (2009)
Kaposi Sarcoma
Kaposi sarcoma (KS) is a cancer that develops from the cells
that line lymph or blood vessels. The abnormal cells of KS
form purple, red, or brown blotches or tumors on the skin.
These affected areas are called lesions. The skin lesions of KS
may look bad, but in many cases, the lesions cause no
symptoms. In other cases, the disease causes painful swelling,
especially in the legs, groin area, or skin around the eyes. KS
can cause serious problems (or even become life threatening)
when the lesions are in the lungs, liver, or digestive tract. KS
in the digestive tract, for example, can cause bleeding, while
tumors in the lungs may cause difficulty breathing.
American Cancer Society 2009
(AIDS-related) Kaposi sarcoma
The most common type of Kaposi
sarcoma in the United States is
epidemic or AIDS-related KS.
This type of KS develops in people
who are infected with HIV, the
virus that causes AIDS. When HIV
damages the immune system,
people who also are infected with
Kaposi sarcoma herpes virus are
more likely to develop KS. KS is
considered to be an "AIDS
defining" illness. This means that
when KS occurs in someone
infected with HIV, that person
officially has AIDS (and is not just
HIV positive).
American Cancer Society 2009
ScienceClarified 2009
 Antibodies appear rapidly after infection through blood
products, usually within 4-7 weeks.
 After sexual transmission, the individual can be infected
yet seronegative for 6-14 months, even years
 In the late stages of the disease, some individuals become
seronegative because of a deficient immune system
McCance & Huether (2006). Pages 285




HIV infection can generally be broken down
into four distinct stages:
primary infection
clinically asymptomatic stage
symptomatic HIV infection
progression from HIV to AIDS
LABORATORY TESTS
1. Serology - the diagnosis of HIV infection is usually based on serological tests.
a. Antibody tests
b. Antigen tests
2. Virus isolation
3. Demonstration of viral NA
4. Prognostic Tests
a. HIV viral load
b. CD4 count
5. Antiviral susceptibility assays
Wong, D. (2009)
Laboratory Diagnosis
Laboratory Diagnosis
1. Serology - the diagnosis of HIV infection is
usually based on serological tests.
(a)Antibody tests - ELISAs are the most
frequently used method for screening of
blood samples for HIV antibody. The
sensitivity and specificity of the presently
available commercial systems approaches
100% but false positive and false negative
reactions occur.
Wong, D. (2009)
Other test systems available include passive particle
agglutination, immunofluorescence, Western blots and RIPA
bioassays. Western blots are regarded as the gold standard
and seropositivity is diagnosed when antibodies against both
the env and the gag proteins are detected. The sensitivity of
the test systems are currently being improved by the use of
recombinant antigens.
Wong, D. (2009)
(b) Antigen tests - HIV antigen can be
detected early in the course of HIV
infection before the appearance of
antibody. It is undetectable during the
latent period (antigen-antibody
complexes are present) but become
detectable during the final stages of the
infection
Wong, D. (2009)
2. Virus isolation - virus isolation is accomplished by the
cocultivation of the patient's lymphocytes with fresh peripheral
blood cells of healthy donors or with suitable culture lines such
as T-lymphomas. The presence of the virus can be confirmed by
reverse transcriptase assays, serological tests, or by changes in
growth pattern of the indicator cells. However virus isolation is
tedious and time consuming (weeks) and is successful in only 70
to 90% of cases. Therefore virus isolation is mainly used for the
characterization of the virus.
Wong, D. (2009)
3. Demonstration of viral NA - this can be
accomplished by probes or by PCR techniques.
The latter may be useful because of its
extremely high sensitivity.
Wong, D. (2009)
4. Prognostic Tests - the following may be useful as prognostic
tests;
(1)HIV antigen
(2) (2) Serial CD4 counts
(3) Neopterin
(4) B2-microglobulin.
(5) Viral load. Of these tests, only serial CD4 counts and HIV
viral load are still routinely used.
Wong, D. (2009)
a. HIV viral load - It appears that HIV viral load
has the greatest prognostic value. HIV viral load
in serum may be measured by assays which detect
HIV-RNA e.g. RT-PCR, NASBA, or bDNA. HIV
viral load has now been established as having
good prognostic value, and in monitoring
response to antiviral chemotherapy. Patients with
a low viral load during the incubation period had
a better prognosis than those with a high viral
load. Patients whose viral load decreased
significantly following the commencement of
antiviral therapy had a better prognosis than those
who did not respond.
Wong, D. (2009)
b. CD4 counts - despite the increasing use of HIV-RNA
assays, measurement of CD4 still has important value in
monitoring disease progression and response to antiviral
chemotherapy. whereas CD4 count gives an indication of
the stage of disease. “The measurement of HIV viral
load tells us where the disease is going, whereas CD4
count tells us where the disease is at this moment”
Wong, D. (2009)
TREATMENT
Therapy of HIV is complicated by the fact that the HIV
genome is incorporated into the host cell genome and can
remain there in a dormant state for prolonged periods until
it is reactivated. Effective therapy must be directed against
both free virus and virus-infected cells. The main group of
substances described are
Wong, D. (2009)
The main group of substances described are:
 1. Nucleoside analogues reverse transcriptase inhibitors.
AZT, DDC, DDI and lamuvidine.
 2. Non-nucleoside analogue reverse transcriptase
inhibitors e.g. Nevirapine
 3. HIV Protease inhibitors e.g. Ritonavir, and Indivavir.
They are the most potent inhibitors of HIV replication to
date.
Wong,D. (2009)
DRUG THERAPY
Zidovudine (AZT) was the first anti-viral agent
shown to have beneficial effect against HIV
infection. However, after prolonged use, AZTresistant strains rapidly appears which limits the
effect of AZT
Wong, D. (2009)
Recent clinical trials reported significant benefit in the
use of combination therapy over the use of
monotherapy. The rationale for this approach is that by
combining drugs that are synergistic, non-cross-resistant
and no overlapping toxicity, it may be possible to
reduce toxicity, improve efficacy and prevent resistance
from arising.
Wong, D. (2009)
HAART
In fact, significant success has now been reported for trials
involving multiple agents including protease inhibitors.
The aim of anti-HIV therapy has now shifted from simply
delaying the progression of disease to finding a permanent
cure. We have now entered the era of highly active antiretroviral therapy (HAART).
Wong, D. (2009)
The current consensus is that one should give a potent
combination of agents HAART right from the start
when treatment is indicated. The most popular
combination is AZT and lamivudine plus a protease
inhibitor.
Wong, D. (2009)
GeorgeHouseTrust (2000)
Lamivudine has greater anti-retroviral activity that
AZT alone and is active against many AZT-resistant
strains without significant increase in toxicity.
Wong, D. (2009)
REFERENCES
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http://www.cancer.org/docroot/cri/content/cri_2_4_1x_what_is_kaposis_sarcoma_21.asp
Answers.com (2009). Main symptoms of acute HIV infection. Retrieved November 10, 2009 from:
http://wpcontent.answers.com/wikipedia/commons/thumb/4/4a/Symptoms_of_acute_HIV_infection.png/300
px-Symptoms_of_acute_HIV_infection.png
Avert, (2009). The Different Stages of HIV Infection. Retrieved November 19, 2009 from:
http://www.avert.org/
CDC. (2006). HIV Prevalence Estimates- United States. Retrieved November 7, 2009 from:
http://www.cdc.gov/
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http://www.ght.org.uk/news/category/BBC
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Mallory, W.W. (2009). Know the facts about HIV/AIDS. National Network for Family Resiliency. Retrieved
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http://www.ces.ncsu.edu/depts/fcs/index.html
McCance, K. L. (2006). Pathophysiology. The Biologic Basis for Disease in Adults
and Children. St
Louis, MO: Elsevier
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http://www.prn.org/index.php/provider_resources/prn_artwork
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http://www.thebody.com/content/art6110.html
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http://www.virtualmedicalcentre.com/humanatlas1/vmc_white.asp?anid=0002
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http://virology-online.com/