Pathology 1: HIV & AIDS Flashcards
What happens when a person has HIV?
HIV infects mainly CD4+ T cells, macrophages, and dendritic cells which express the surface receptor CD4.
Destroying CD4+ T cells leads to severe immunologic impairment and eventually death.
What happens in AIDS?
It’s the end stage of disease that is associated with CD4+ T cell depletion, multiple or recurrent opportunistic infections, and unusual cancer (kaposi sarcoma).
HIV belongs to which virus family?
Retroviridae.
The virion in HIV consists of what?
1- glycoprotein envelope (gp120, gp41).
2- matrix layer (p17).
3- capsid (p24).
4- two copies of (+) ssRNA.
5- enzymes (reverse tanscriptase, integrase, protease).
The HIV genome consists of ____ genes.
And what are they?
9 genes.
1- 3 structural genes (gag, pol, env).
2- 6 non-structural genes (tat, nef, rev,vif, vpr, vpu).
Which protein encode the gene “pol” and what is the function of proteins?
Protein: reverse transcriptase.
Function: transcribes RNA genome into DNA.
Which proteins encode the gene “env” and what is the function of proteins?
1- gp120: attachment to CD4 protein.
2- gp 41: fusion with host cell.
Which protein encode the gene “tat” and what is the function of proteins?
Protein: tat.
Function: activation of transcription of viral genes.
Which protein encode the gene “rev” and what is the function of proteins?
Protein: rev.
Function: transport of late mRNAs from nucleus to cytoplasm.
Which protein encode the gene “nef” and what is the function of proteins?
Protein: nef.
Function: decreases CD4 proteins.
Which protein encode the gene “vpr” and what is the function of proteins?
Protein: vpr.
Function: transports viral core from cytoplasm into nucleus.
List the 2 HIV species known to cause AIDS?
1– HIV-1.
2- HIV-2.
What are the properties of HIV-1?
- Causes HIV infection worldwide.
- Highly virulent.
- Highly susceptible to mutations.
What are the properties of HIV-2?
- Causes the infections in specific regions e.g. West Africa.
- Relatively less virulent.
- Relatively less susceptible to mutations.
List the 3 methods of transmission of HIV?
1- sexually (unprotected sex).
2- parenterally.
3- perinatally (from mother to baby).
How is HIV transmitted sexually through unprotected sex?
The virus is present in blood, semen and vaginal secretions.
How is HIV transmitted parenterally?
- Direct exposure to infected blood of body fluids (e.g. receiving blood from infected donor).
- Using contaminated or not adequately sterilized tools in surgical or cosmetic practice (dental, tattooing, body piercing).
- Sharing contaminated needles, razors, or tooth brushes.
How is HIV transmitted perinatally (from mother to baby)?
- Infected mother can transmit HIV to their babies transplacentally (25%).
- Virus spread to child perinatally mainly (50%) during delivery (most common way).
- Breastfeeding is also an important way of perinatal transmission (25%).
HIV is ________ inactivated.
Easily inactivated.
How is HIV inactivated?
By treatment for 10 min at 37C with any of the following:
- 10% house hold bleach, sodium hypochlorite.
- 50% ethanol.
- 35% isopropanol.
- 0.5% paraformaldehyde.
- 0.3% hydrogen peroxide.
HIV infection is divided to how many stages? and based on what?
3 stages, based on CD4+ T cell count and presence of opportunistic infections.
List the 3 stages of HIV infection?
1- the acute phase.
2- the chronic phase (PGL, ARC).
3- AIDS (the end stage of the disease).
How long is the incubation period for the acute phase of HIV infections?
Incubation period is 2 weeks and lasts for about 12 weeks.
What are the symptoms in acute phase of HIV infection?
Mostly asymptomatic, but in 25-65% of the cases, patients may develop symptoms that resemble infectious mononucleosis or flu (fever, headache, anorexia, fatigue, lymphadenopathy, skin rash) which resolves in 2 weeks.
