2. HIV
• Human immunodeficiency virus (HIV)is the cause
of acquired immunodeficiency syndrome (AIDS).
• It belongs to the lentivirus subfamily of the
retroviridae.
•
• Both HIV-1and HIV-2 cause AIDS, but HIV-1 is
found worldwide , whereas HIV-2 is found primarily
in West Africa.
3. STRUCTURE
• HIV has a bar-shaped(type D)core surrounded by an
envelope containing virus specific glycoproteins (gp120
and gp4).
• The genome of HIV consists of two identical molecules of
single-stranded RNA and is said to be diploid.
• In addition to three typical retroviral genes gag, pol and
env which encode structural proteins, genome RNA has
six regulatory genes.
• Two of these genes tat and rev are required for replication
and other four nef,vif,vpr and vpu are accessory genes.
5. PATHOGENESIS
• The prominent immunosuppression seen in AIDS is due
to depletion of T4 helper lymphocytes.
• In immediate period after exposure , HIV is in high level in
the blood.
• It settles down to low level during incubation period
.during incubation period massive turnover of CD4 cells,
CD4 cells are killed by HIV are replaced efficiently.
• Eventually immune system succumbs , AIDS develop
when no longer CD4 cells can be replaced by HIV .
7. REPLICATION
• The initial step is entry of HIV into the cell is binding of
virion gp120 envelope protein to CD4 protein on cell
surface.
• RNA genome is then reverse transcribed into a DNA
provirus which is then integrated into host cell DNA.
This is followed by synthesis and maturation of virus
progeny.
8.
9. CLINICAL FINDINGS
• It has following three stages;
• Acute Stage usually begins 2 to 4 weeks after infection a
mononucleosis like picture of fever, sore throat, and generalized
lymphadenopathy occurs.
Maculopapular rash on the trunk, arms and legs sparing
the pals and soles is seen.
Leukopenia occurs and high level viremia occurs, infection is readily
transmitted during this stage. This stage is resolved in app.2 weeks
spontaneously.
11. • Middle/Latent Stage long period measured in years. If untreated
lasts for 7 to 11 years. Patient is asymptomatic during this period.
• Large amount of HIV produced by lymph nodes.
• A syndrome called AIDS can occur during this period.
• Persistent fever, fatigue, weight loss and lymphadenopathy.
12. • Late Stage of HIV is AIDS manifested by increase in
opportunistic infections.
• These infections include pneumonia, tuberculosis,
• Ulcers of mouth ,esophagitis ,meningitis, kaposi’s
sarcoma and retinitis.
13. • Other Manifestations
• It is now recognized that HIV infected patients may
develop a number of manifestations that are mot
explained by opportunistic infections or tumours.
• The most frequently neurological disorder is AIDS
encephalopathy which is seen in two thirds of
majority.
• Other manifestations include skin eruptions and
persistent diarrhea.
16. • Sexual transmission;
• patient to healthy individual.
• Unsafe sexual practice.
• Blood/Blood products;
• intravenous drug abusers
• Contaminated blood transfusions
• Vertical transmission;
• Transmission rate from mother to newborn vareis from
about 15% in Europe to 50% in Africa.
• May occur through transplacental route, perinatally during
birth process or postnatally during breast feeding.
17. Laboratory Diagnosis
• Serology is usual method used for its diagnosis . Can be
divided into screening and confirmatory assays.
• Western blot also known as immunoblot analysis is gold
standard for serological diagnosis. It has lower sensitivity
than ELISA.
• ELISA test is the most frequently used screening test.
• In western blot there is line immunoassaya incorporate
HIV antigens on nitrocellulose strips .
18. TREATMENT
• HIV medicines are grouped into 6 classes;
• Non nuleoside reverse transcriptase inhibitors(NNRTIS)
• Nucleoside reverse transcriptase inhibitors (NRTIs)
• Protease inhibitors (PIs)
• Fusion inhibitors
• CCR5 antagonists (CCR5s) (also called entry inhibitors)
• Integrase strand transfer inhibitors (INSTIs)
• However there is no specific treatment of AIDS medicines
are used to prevent further infections.
