infectious diseases

1. 2017
National Centre for AIDS
and STD Control
Basics of HIV/AIDS

2. 2017
National Centre for AIDS
and STD Control
Objectives
• Explain the difference between HIV and AIDS.
• Discuss the natural course of HIV infection.
• Discuss mode of transmission of HIV.

3. 2017
National Centre for AIDS
and STD Control
Definition of HIV
• HIV stands for human
immunodeficiency virus,
the virus that causes AIDS.
– H: Human
– I: Immunodeficiency
– V: Virus

4. 2017
National Centre for AIDS
and STD Control
Effects of HIV
• HIV breaks down the body's
defence against infection and
disease—the immune system
• HIV destroys specific white blood
cells (CD4 cells) → weakens the
immune system
• The body cannot fight illness
• Then the person may develop
opportunistic infections (OIs)

5. 2017
National Centre for AIDS
and STD Control
Effects of HIV (Continued)
It is chronic manageable condition

6. 2017
National Centre for AIDS
and STD Control
Definition of AIDS
• AIDS stands for Acquired Immunodeficiency Syndrome and
refers to the most advanced stage of HIV infection.
– A: Acquired — (not inherited) to differentiate from a
genetic or inherited condition
– I: Immuno — refers to the immune system
– D: Deficiency — inability to protect against illness
– S: Syndrome — a group of symptoms or illnesses that
occur as a result of HIV

7. 2017
National Centre for AIDS
and STD Control
HIV & AIDS
What is the difference between
HIV & AIDS?

8. 2017
National Centre for AIDS
and STD Control
HIV & AIDS (Continued)
• HIV: the virus that causes HIV infection
• AIDS: a group of serious illnesses and opportunistic
infections that occur when HIV has further
suppressed the immune system
• Most people who are HIV-infected will develop AIDS
after some time. It may be from several months to 15
years.

9. 2017
National Centre for AIDS
and STD Control
CD4 & Viral Load
What are CD4 & Viral Load?

10. 2017
National Centre for AIDS
and STD Control
CD4
• CD4 count: number of CD4 cells in the blood
• CD4 cell: a type of white blood cell that is the
immune system's key “infection fighter”
CD4 count reflects the “health” of the immune
system

11. 2017
National Centre for AIDS
and STD Control
CD4 (Continued)
• When HIV actively multiplies, it infects and kills CD4
cells.
• The CD4 count is expressed as the number of cells
per cubic millimetre.
– Normal count in healthy adult: 500−1500 cells/mm3
– Below 200 cells/mm3: increased risk of serious HIV-
related infections

12. 2017
National Centre for AIDS
and STD Control
Use of CD4
• Patients with severe immunodeficiency may not always
show clinical symptoms.
– CD4 counts can be used to guide initiation of
cotrimoxazole
– CD4 can help identify ART treatment failure and the need
to switch to a second-line ART regimen.
As per the Latest Guideline all HIV Positive should
be enrolled in ART irrespective of CD4 count

13. 2017
National Centre for AIDS
and STD Control
Viral Load (Continued)
• Viral load: amount of HIV in the blood
– Very high after initial infection with HIV
• High viral load = high risk of transmission of HIV
– When body develops antibodies to HIV, viral load falls
– As immune system gets weaker, viral load goes up again
– High viral load signals disease progression
– Measured with PCR test

14. 2017
National Centre for AIDS
and STD Control
CD4 & Viral Load (Continued)

15. 2017
National Centre for AIDS
and STD Control
Opportunistic Infection (OI)
An opportunistic infection (OI) is an illness caused
by a germ that might not cause illness
in a healthy person, but will cause illness in a person
with a weak immune system.

16. 2017
National Centre for AIDS
and STD Control
Opportunistic Infection (OI)
(Continued)
Tuberculosis (TB)

17. 2017
National Centre for AIDS
and STD Control
Routes of Transmission
How is HIV transmitted?

18. 2017
National Centre for AIDS
and STD Control
Routes of Transmission (Continued)
Encourage all pregnant women to
practise safer sex

19. 2017
National Centre for AIDS
and STD Control
Routes of Transmission (Continued)
1. Unsafe sexual contact
– Unprotected sexual intercourse
– Contact with HIV-infected body fluids
during other sexual contact (oral and anal)
• Blood
• Semen
• Breast milk
• Cervical or vaginal secretions
• Other body fluids containing blood Heterosexual
intercourse is the most
common route of HIV
transmission globally

20. Routes of Transmission (Continued)
2. Infected blood and blood products
–Transfusion
–Direct contact with HIV-blood through broken skin
–Occupational exposure
–Re-using sharp instruments to cut/pierce the skin during medical,
recreational, ceremonial, religious, or tatooing procedures
– Sharing and reusing needles

21. Routes of Transmission (Continued)
3. Mother-to-child transmission
(MTCT)
– During pregnancy
– During labour and delivery
– During breastfeeding

22. HIV is not transmitted by:
• Coughing or sneezing
• Touching or hugging
• Kissing
• Shaking hands
• Working or going to school
with a person who is HIV-
infected
• Sharing cups, glasses,
plates, or other utensils
• Being bitten by an insect
• Using the telephone
• Using public baths, pool,
or toilets
• Sharing water or food