Human Immunodeficiency Virus Flashcards
1
Q
Structure of HIV
A
- outer envelope (from host cell membrane) + inner envelope
- glycoproteins: gp120 (attachment to CD4 receptor), gp41 (fusion of envelopes to enter target)
- core enzymes: reverse transcriptase, integrase, protease
- 2 strands of ssRNA, 9 genes, of which 3 encode structural proteins
2
Q
Structure of HIV
A
- outer envelope (from host cell membrane) + inner envelope
- glycoproteins: gp120 (attachment to CD4 receptor), gp41 (fusion of envelopes to enter target)
- core enzymes: reverse transcriptase, integrase, protease
- 2 strands of ssRNA, 9 genes, of which 3 encode structural proteins
3
Q
Variations of HIV
A
- HIV-1, HIV-2 (1 is predominant)
- many strains & subtypes - tends to mutate a lot + low fidelity of transcription of RT)
4
Q
Transmission of HIV
A
Direct body fluid exchange
- sexual transmission (increased risk w existing STDs)
- blood transmission
- vertical transmission
5
Q
Stages of HIV infection (4)
A
- Incubation - asymptomatic
- Acute Seroconversion Phase
- acute signs & viremia (very transmissible)
- leukopenia, resolution within 2 weeks (more CTLs, IgM, IgG) - Asymptomatic/Latent Phase
- 7-11 years, viremia levels low
- anti p-24 IgG high, anti p41 IgG stays high - AIDS
- decreased CD4+ T cell count, anti p-24 IgG declines
- increased freq & severity of opportunistic infections - death
6
Q
Symptoms of HIV infection
A
- Acute phase
- mononucleosis-like infection: fever, sore throat, lethargy, generalised lymphadenopathy, maculopapular rash on arms, legs, trunk (x palms, soles) - Latent phase
- AIDS-related complex (ARC)
- fever, fatigue, weight loss, lymphadenopathy - AIDS
- malignancies: Kaposi’s sarcoma, verebral/NHL
- protozoal/fungal/bacterial/viral
- neurologic: progressive multifocal leukoencephalopathy, AIDS dementia, neuropathy
- skin lesions
7
Q
Diagnosis of HIV infection (5)
A
- ELISA - detects anti-p24
2. Western blot - detect gp41 & p24 - confirmatory
8
Q
Variations of HIV
A
- HIV-1, HIV-2 (1 is predominant)
- many strains & subtypes - tends to mutate a lot + low fidelity of transcription of RT)
9
Q
Transmission of HIV
A
Direct body fluid exchange
- sexual transmission (increased risk w existing STDs)
- blood transmission
- vertical transmission
10
Q
Stages of HIV infection (4)
A
- Incubation - asymptomatic
- Acute Seroconversion Phase
- acute signs & viremia (very transmissible)
- leukopenia, resolution within 2 weeks (more CTLs, IgM, IgG) - Asymptomatic/Latent Phase
- 7-11 years, viremia levels low
- anti p-24 IgG high, anti p41 IgG stays high - AIDS
- decreased CD4+ T cell count, anti p-24 IgG declines
- increased freq & severity of opportunistic infections - death
11
Q
Symptoms of HIV infection
A
- Acute phase
- mononucleosis-like infection: fever, sore throat, lethargy, generalised lymphadenopathy, maculopapular rash on arms, legs, trunk (x palms, soles) - Latent phase
- AIDS-related complex (ARC)
- fever, fatigue, weight loss, lymphadenopathy - AIDS
- malignancies: Kaposi’s sarcoma, verebral/NHL
- protozoal/fungal/bacterial/viral
- neurologic: progressive multifocal leukoencephalopathy, AIDS dementia, neuropathy
- skin lesions
12
Q
Diagnosis of HIV infection (5)
A
- ELISA - detects anti-p24
- Western blot - detect gp41 & p24 - confirmatory/definitive
- RT-PCR/PCR - detect viral laod
- OraQuick - screening test
- p24 antigen test
13
Q
Treatment of HIV (4)
A
- No vaccine
- Antiretroviral drugs - nRTIs (zidovudine, lamivudine), nnRTIs (efavirenz, nevirapine), PIs (saquinavir, indinavir), HAART therapy
- Prophylaxis (post exposure, following needlestick injury) - zidovudine + lamivudine + protease inhibitor
- Use of condoms, not sharing needles, screening blood, administer zidovudine/nevirapine perinatally to HIV infected mothers & neonates, do not breastfeed
