HIV
Introduction
HIV (human immunodeficiency virus) is a
virus that attacks human immune system . If
HIV is not treated, it can lead to AIDS
(acquired immunodeficiency syndrome).
There is currently no effective cure. But with
proper medical care, HIV can be controlled
HIV attacks white blood cells ,especially CD4
cells . HIV destroys these CD4 cells,
weakening a person’s immunity against
opportunistic infections, such as tuberculosis
and fungal infections, severe bacterial
infections and some cancers.
Cd4 level in normal individuals is between 500 to 1500 cells/mm3 and in HIV patient it
drops to 200 cells/mm3
Human immunodeficiency virus (HIV) is a retrovirus of the lentivirus family that contains
only RNA
There are 2 types of virus :-HIV-1 and HIV-2
HIV-1 is most common type and has led to worldwide AIDS epidemic
Structure
The HIV virion is about 100 -120 nm in diameter.
Its innermost region consists of a cone-shaped core that
includes two copies of the (positive sense) ssRNA genome,
the enzymes reverse transcriptase, integrase and protease,
some minor proteins, and the major core protein.
The genome of human immunodeficiency virus (HIV)
encodes 8 viral proteins playing essential roles during the HIV
life cycle.
The single-stranded RNA is tightly bound to
p7 nucleocapsid proteins
The envelope of the virion is formed by a plasma
membrane of host cell origin, which is supported by a matrix
composed of the viral p17 protein, ensuring the integrity of
the virion particle
HIV Genome
• The HIV genome contains nine genes that encode fifteen viral proteins.
• These are synthesized as polyproteins which produce proteins for virion
interior, called Gag, group specific antigen; the viral enzymes or the
glycoproteins of the virion env (envelope).
• HIV encodes for proteins which have certain regulatory and auxiliary
functions as well. HIV-1 has two important regulatory elements: Tat and
Rev and few important accessory proteins such as Nef, Vpr, Vif and Vpu
which are not essential for replication in certain tissues.
• The GAG gene provides the basic physical infrastructure of the virus,
and POL provides the basic mechanism by which retroviruses reproduce,
while the others help HIV to enter the host cell and enhance its
reproduction.
Epidemology
• The global pandemic of HIV
began in 1981
• It was first detected in central
Africa
• According to WHO as of 2021
HIV has killed approx. 40.1
million people and approx.
38.4 million people are
infected with HIV globally
• There were about 7,70,000
deaths in 2018 and 6,80,000
deaths in 2020
HIV In India
•HIV was first detected in India in 1986
•First known case was diagnosed six female sex workers in
Chennai
•The National AIDS Control Organization (NACO) estimated
that 2.14 million people lived with HIV/AIDS in India in
2017. India is home to the world's third-largest population
of persons with HIV/AIDS (as of 2018, with South Africa and
Nigeria having more)
•Maharashtra was estimated to have the highest number of
new HIV infections in 2019
•he main factors which have contributed to India's large HIVinfected population are extensive labour migration and
low literacy levels in certain rural areas resulting in a lack of
awareness and in gender disparities.
• The Government of India has also raised concerns about the
role of intravenous drug use and prostitution in spreading
AIDS.
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