AIDS is caused by HIV infection and progresses through three stages. Stage 1 involves acute infection with flu-like symptoms. Stage 2 can last 10-15 years without symptoms as HIV slowly damages the immune system. Stage 3 is AIDS, where opportunistic infections occur due to severe immune deficiency. HIV primarily infects CD4 cells. It enters cells and integrates into the host DNA, then uses cell machinery to replicate. Antiretroviral treatment can suppress HIV and prevent AIDS symptoms.

1. AIDS

2. Acquired immunodeficiency
syndrome (AIDS) is a spectrum of
conditions caused by infection with
the human immunodeficiency virus
(HIV). The immune system becomes
weaker and weaker in this disease
and as a result many pathogens
infect the patients body.

3. Stage 1 – Acute primary infection
Stage 2 – The asymptomatic stage
Stage 3 – Symptomatic HIV infection (AIDS)

4. Stage 1 ( acute primary infection)
Symptoms can include:
 fever (raised temperature)
 rash
 sore throat
 swollen glands
 headache
 upset stomach
 joint aches and pains
 muscle pain.
These symptoms occur
because the body is reacting
to the HIV virus. Cells that are
infected with HIV are
circulating throughout your
blood system. In response, the
immune system tries to attack
the virus by producing HIV
antibodies – this process is
called seroconversion.

5. Stage 2 (asymptomatic stage)
Once a person has been through the acute primary infection stage
and seroconversion process, they often start to feel better. In fact,
HIV may not cause any other symptoms for up to 10 or even 15
years (depending on age, background and general health).
However, the virus will still be active, infecting new cells and making
copies of itself. HIV can still be passed on during this stage. If left
untreated, over time, HIV infection will cause severe damage to the
immune system.

6. Stage 3 ( HIV infection or AIDS)
weight loss
chronic diarrhea
night sweats
fever
persistent cough
mouth and skin problems
regular infections
serious illness or disease.
If a person develops certain
serious opportunistic
infections or diseases – as a
result of damage to their
immune system from
advanced stage 3 HIV
infection – they are said to
have AIDS.

8. The three main transmission routes of HIV are
 Unsafe sexual contact with an HIV infected patient.
 Exposure to infected body fluids or tissues (blood, semen etc).
 Sharing needles or syringes with HIV infected people is extremely
dangerous
 From mother to child or foetus. This can occur during pregnancy,
childbirth, or breastfeeding (through breast milk). Mother-to-child
transmission of HIV is also called perinatal transmission of HIV.

9.  Helper T cells are the most important cells in adaptive immunity, as
they are required for almost all adaptive immune responses.
 They help in activating B cells to secrete antibodies and
macrophages to destroy ingested microbes
 They also help activate cytotoxic T cells to kill infected target cells.
 They produce special proteins, called cytokines, which regulate the
immunity, inflammation and Hematopoiesis (is the production of all
of the cellular components of blood and blood plasma).

10.  HIV is a retrovirus so it has RNA as its
genome. It has the power of reverse
transcription.
 It primarily infects vital cells on the
human immune system such as T4
cells, macrophages and dendritic cells
(mainly T4 cells).
 HIV infects human cells and uses the
energy by those cells to grow and
reproduce.

11.  Entry of the virus
HIV enters the cells through receptors. Its absorbs its glycoproteins
to the receptors on the target cell, then fusion of the viral capsid to
the cell membrane occurs. Then the contents of the capsid are
injected into the cell.
 Replication and integration
Enzyme reverse transcriptase transcribes single stranded RNA
genome into a double stranded DNA, which is then integrated into
the hosts chromosome with the help of enzyme integrase.
The integrated viral DNA then lies dormant.

12. This is called the latent stage of HIV infection
In this stage the viral DNA is called DNA provirus. Its keeps
replicating along with the host cell’s genome.
 Assembly and release
In the presence of transcription factors the proviral DNA becomes
active and starts active replication.
During this, the DNA provirus generates genomic RNA which also
serves as mRNA and helps in synthesis of viral proteins.
The mRNA and viral RNA come out of nucleus into the cytoplasm.
These contents are then assembled and packaged into new virus
particles

13. Important enzymes
 Reverse
transcriptase
 Integrase
 transcriptase
 Protease

14.  ELISA Test - ELISA, which stands for enzyme-linked immuno
sorbent assay, is used to detect HIV infection.
 Saliva Tests - A cotton pad is used to obtain saliva from the inside
of the patient’s cheek. The pad is placed in a vial and submitted to
a laboratory for testing. Results are available in three days.
 Viral Load Test - This test measures the amount of HIV in your
blood. Generally, it's used to monitor treatment progress or detect
early HIV infection.

15.  Reverse transcriptase inhibitors – these drugs attack the reverse
transcriptase enzyme which is vital of viral multiplication. Eg-
delavirdine, efavirenz etc.
 Protease inhibitors – these drugs attack HIV enzyme protease Eg
– amprenavir, indinavir etc.
 Fusion inhibitors – these drugs stop the virus from entering new
cells. Eg- enfuvirtide.
 HAART- highly active anti-retroviral therapy. This treatment can
reduce the amount of HIV in the bloodstream and sometimes
enables the body’s immune cells to rebound to normal levels.
 Pre exposure and Post exposure treatment(PEP)

16. Abstinence or delay of sexual activity.
Using condoms or contraceptives.
Avoiding sharing of needles and syringes.
Mother to child
World AIDS Day, designated on 1 December every year since 1988,
is an international day dedicated to raising awareness of the AIDS
pandemic caused by the spread of HIV infection and mourning
those who have died of the disease