HIV

Question 1

disease epi

Answer 1

pneumocystis pneumonia noted in gay man(1979 - 1981
LA California - 5 cases of 
Caused by Pneumocystis jirovecii.)
oral candidiates
kaposi's sarcoma
lymphadenopathy

Question 2

Other people with this cluster of symptoms:

Answer 2

Recipients of blood transfusion
Hemophiliacs receiving blood clotting factors
IV drug users
Female sex partners of men with AIDS
Etiology most likely a virus.

Question 3

The oldest ancestor of HIV-1 to date is from

Answer 3

the Democratic Republic of Congo (DRC).

Question 4

change in new HIV

Answer 4

-18%

Question 5

etiology

Answer 5

male-male 67%
female-male 80%
sex
blood
saliva?

Question 6

risk by exposure

Answer 6

90-100% transfusion
15-25% vertical
3% receive anal sex
0.7% needle

Question 7

Hiv risk

Answer 7

HIV is present in semen and vaginal secretions.
Transmission from men to women is more efficient than from women to men.
Receptive anal sex and needle sharing are even more efficient.
Transmission rate is increased by breaks in mucosa
genital sores, abrasions.
Transmission occurs in 1/10-1000 heterosexual contacts, highly dependent on how
much virus the transmitter has in their body.
The likelihood of transmission is greatly reduced by the reduction in viral load that
results from antiviral treatment.

Question 8

HIV structure

Answer 8

RNA
reverse transcriptase
capsid
matrix
lipid membrane
glycoproteins: gp41-transmembrane portion
gp 120-docking(top portion)
circular=not mature
conical=mature
isohedral
release by budding

Question 9

replication

Answer 9

binding to receptor membrane
fusion with cell membrane
reverse transcriptase(RNA-->DNA)
integration into chromosome
transcription
translation
packaging of RNA
budding

Question 10

therapy aim

Answer 10

1. reverse transcriptaseinhibitor AZT

2. protease inhibitor

Question 11

with HAART

Answer 11

CD4 level is the same

viral load low or undetectable

Question 12

HIV Infection

Answer 12

Activated CD4+ T cells - these cells make most of the virus

Resting CD4+ T cells - these are few but are often latently infected
and cannot currently be eliminated.
If a patient stops HAART, virus from these cells will begin replicating.

Macrophages - can be persistently infected for long periods and
apparently don’t die from infection, though their function is impaired.
HIV can reach the brain when monocyte/macrophages pass the
blood-brain barrier and enter as microglial cells.

Question 13

HIV reservoirs

Answer 13

cns
T cells
macrophages and dendritic cells
GI tract

Question 14

Diagnosis

Answer 14

1. Primary screen
Rapid and sensitive but can can
have false positive
2. Confirmatory test
Will not have false positives
More expensive, more laborious

-Antibody - will not pick up recent infection
• ELISA - primary screen - high sensitivity
• Western Blot - confirmatory - high specificity
• Rapid antibody test - false positives can be problematic
- requires confirmation
OraQuickTM
-Combination test - measures both Ab and antigen, both primary and confirmatory in one screening.
-Nucleic acid tests - Viral RNA used primarily to screen blood supply
also to measure viral load and to detect recent infection

Window period (eclipse period) prior to seroconversion can last weeks

Question 15

Oral AIDS defining illnesses

Answer 15

• Esophageal candidiasis
  but not oral candidiasis
• Oral hairy leukoplakia (OHL)
• Kaposi’s sarcoma (KS)