12 - HIV disease and AIDS Flashcards
(55 cards)
HIV Risk Assessment (Risk Factors)
a. History of sexually transmitted disease(s) (STD’s)
b. History of hepatitis B
c. History of multiple sexual partners or a partner with multiple sexual partners
d. History of IV drug use
e. Woman with IV drug user sex partner
f. Homosexual/bisexual man
What are the three structural genes in HIV and what do they code for?
gag gene: encodes for proteins
env gene: encodes for envelope glycoproteins (gp)
pol gene: encodes for enzymes (polymerase)
p24
“core protein” inner shelf of nucleocapsid; clinically, used as marker for viral replication
p17
outer shelf
p9
structural proteins
p7
structural proteins
gp120
major envelope protein mediates attachment to CD4 receptors and co-receptors
gp41
helps mediate fusion of the virus to the host cell
Reverse transcriptase (RT)
RNA-dependent, DNA polymerase transcribes viral RNA into dsDNA
Integrase
helps integration of viral DNA into the host genome
Protease
aids in maturation of the virion after budding
Which gene encodes for a major envelope protein that mediates attachment to CD4 receptors and co-receptors?
gp120
Which gene encodes for a glycoprotein that helps mediate fusion of the virus to the host cell?
gp41
Which gene encodes for a core protein that makes up the inner shelf of nucleocapsid
p24
What are the steps in the HIV life cycle?
- Attachment – Viral Envelope proteins – gp 120 and gp 41
Cell receptors for HIV:
• CD4 receptor
• Co-receptors – CCR-5 (β-chemokine receptor 5)
– CXCR-4 (Fusin), (α-chemokine receptor 4) - Fusion
- Uncoating
- Transcription – RNA → dsDNA by RT
- Integration of HIV DNA into host genome
- HIV expression – regulatory genes, structural genes
- Assembly of virion
- Budding
- Maturation – by protease enzyme
What clinical tests are used in the diagnosis of HIV infection? What do they test for?
ELISA (enzyme linked immunosorbent assay): detects antibodies.
Reactive/nonreactive.
Nonreactive > negative
Reactive > repeat. Reactive again > Western blot
Western Blot (gel immunoelectrophoresis): detects antibodies for three key bands (gp120/160, gp41, p24) Positive = 2/3 key bands Indeterminate: 1 key band and/or accessory bands found Negative = no key bands Western blot = CONFIRMATORY TEST
CDC guidelines on HIV testing recommends that those at high risk should be tested how often? Who are those at risk?
1) IDU or sex partners of IDU
2) Sex for money or drugs
3) Sexual partner of a known HIV infected patient
4) Men who have sex with men (MSM)
5) Having more than one sexual partner, or have a sexual partner who has more than one sexual partner
6) Beginning a new sexual relationship
CDC Definition of AIDS?
Positive HIV test AND
CD4 count <200 OR AIDS indicator condition
What are the most common methods of transmission of AIDS in the United States?
- Male-to-male sexual contact
- Heterosexual contact
- Male-to-male sexual contact and IDU
- Other
What is the leading mode of HIV transmission worldwide?
Heterosexual contact
What are potentially infectious body fluids?
Blood
Visibly bloody fluid
Semen, vaginal secretions
CSF, synovial, pleural, peritoneal, pericardial and amniotic fluids
What are bodily fluids that are not considered infectious?
Saliva (non-bloody) Tears Sweat Urine (non-bloody) Feces (non-bloody)
What is the standard of care in antiviral treatment for AIDS?
Standard of care is multi-drug combinations = Highly Active Anti-Retroviral Therapy (HAART)
What criteria are used to assess when antiviral therapy should be initiated?
Viral load and CD4 count are used to assess when antiviral therapy should be initiated.
a. Low CD4 count indicates immune deficiency/advanced disease and is a criterion for initiating therapy.
b. High viral loads prognosticate that disease will advance rapidly and therefore can be used as rationale to initiate therapy.
c. Earlier initiation has become the recommended, to decrease general inflammation.
