The document discusses Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS). It explains that HIV is a retrovirus that causes AIDS by infecting and damaging the immune system. HIV is transmitted via bodily fluids and can be passed from mother to child during pregnancy, birth, or breastfeeding. While HIV infection may be asymptomatic for years, it eventually leads to AIDS if untreated, characterized by life-threatening opportunistic infections. Laboratory diagnosis of HIV infection involves serological tests to detect HIV antibodies.

1. HUMAN
IMMUNODEFICI
ENCY
VIRUS (HIV)

2. Learning Objective
 At the end of this chapter, students are
expected to:
 Explain the disease characteristics and
clinical manifestation of HIV.
 Describe and practice the laboratory
diagnosis of HIV.

3. Introduction to HIV
 HIV is a member of the family retroviridae,
a type D retrovirus that belongs to the
lentivirus subfamily. HIV-1 and HIV-2 are
medically important viruses. The two
viruses are 40% similar in their overall
structures, and both can cause AIDS.

4. 4
What is HIV?
• Human: Infecting human beings
• Immunodeficiency: Decrease or weakness
in the body’s ability to fight off infections and
illnesses
• Virus: A pathogen having the ability to
replicate only inside a living cell

5. 5
Types of HIV Virus
 HIV 1
 Most common in sub-Saharan Africa and
throughout the world
 HIV 2
 Most often found in West Central Africa, parts of
Europe and India

6. 6
Structure of HIV
Envelo
pe
Core p24
RNA
Reverse
Transcriptase

7. 7
What is AIDS?
Acquired: To come into possession of
something new
Immune Deficiency: Decrease or weakness in
the body’s ability to fight off infections and
illnesses
Syndrome: A group of signs and symptoms
that occur together and characterize a particular
abnormality
AIDS is the final stage of the disease caused by
infection with a type of virus called HIV.

8. 8
HIV vs. AIDS
 HIV is the virus that causes AIDS
 Not everyone who is infected with HIV has
AIDS
 Everyone with AIDS is infected with HIV
 AIDS is result of the progression of HIV
Infection
 Anyone infected with HIV, although healthy,
can still transmit the virus to another person

9. 9
How is HIV Transmitted?
 Unprotected sexual
contact with an infected
partner
 Exposure of broken skin
or wound to infected
blood or body fluids
 Transfusion with HIV-
infected blood
 Injection with
contaminated objects
 Mother to child during
pregnancy, birth or
breastfeeding

10. Transmission of HIV
 The virus transmits through sexual intercourse,
blood transfusion or by contaminated needle.
Sexual transmission, either heterosexual or male-to-
male is a well-documented route of transmission.
 Children born to women with HIV have a 20% to 30%
risk of HIV infection.
 Infected mothers can also spread HIV to their
newborn infants by breast-feeding.

11. Disease Characteristics and
Clinical Manifestation
 Infection with HIV produces a chronic infection with
symptoms that range from a symptomatic to the
end stage complications of AIDS.
 Typically, patients in the early stages of HIV
infection are either completely asymptomatic or
may show mild, chronic swelling of lymph nodes.
 The early phase may last from many months to
many years after viral exposure.

12. Disease Characteristics and
Clinical Manifestation
 Typically, patients in the early stages of HIV
infection are either completely asymptomatic or
may show mild, chronic swelling of lymph
nodes.
 The early phase may last from many months to
many years after viral exposure.
 This phase is followed by a prolonged period
of clinical latency range 7 to 11 years.

13. Disease Characteristics and
Clinical Manifestation
 Clinical symptoms of the later phase of the disease
include extreme weight loss, fever and multiple
secondary infections. The end stage of AIDS is
characterized by the occurrence of opportunistic
infection like M. tuberculosis, Salmonella, P.carinii,
etc.

15. Laboratory Diagnosis
 A ‘window’ period of seronegativity exists from the
time of initial infection to 6 or 12 weeks or longer.
 Serological screening tests designed to detect HIV
antibodies are usually enzyme linked
immunosorbent assay and dot blot assay; western
blot assay is commonly used confirmatory test.