HIV Flashcards
Name three bodily fluids associated with HIV transmission, what routes can HIV be transmitted?
Vaginal fluid, semen, breast milk
- Sexually; anal sex highest risk
2, Vertical transmission - IDU: HIV can live in a used needle for up to 42 days
- Transfusion via blood products and organ/tissue transplants
What are the chances of an HIV positive mother passing HIV onto her child if she’s received appropriate medical intervention?
Less than 1%
When can an HIV mothers have a normal vaginal delivery and will the baby be given?
If she’s had treatment to suppress the virus and the baby will receive post-exposure prophylaxis
Which types of exposure has the highest estimated risk of HIV transmission?
Receptive anal intercourse
Name 5 other factors that increase the risk of transmission
- A high plasma HIV viral load (more virus around = more infectious)
- Breaches n the mucosal barrier that make HIV access easier; mouth, genital ulcers, trauma, menstruation or bleeding can facilitate transmission
- Ejaculation
- STIs enhance HIV transmission
- Non-circumcision (the inner surface of the foreskin is rich in HIV receptors)
What comprises post-exposure prophylaxis (PEP)?
28 days of HIV therapy to reduce the risk of acquiring HIV from the incidence
What happens when HIV enters the body?
HIV accesses cells via the CD4 receptor and uses reverse transcriptase to make a DNA copy of the RNA genome, which integrates into the host’s DNA. During replication complete virus particles are formed and erupt from the cells.
There is progressive damage to the immune system leading to severe immunodeficiency (primarily depletion and impaired function of CD4 T lymphocytes), opportunistic infections and death
Name two things that HIV induces that are likely to contribute to CD4 lymphocyte loss
Apoptosis and inhibition of CD4 lymphocyte growth
Describe the natural history of HIV in the body after initial infection
- Acute seroconversion: occurs in 50% of people infected within a few weeks of the initial infection and marks the period of time where HIV antibodies grow and are detectable. There is a drop in CD4+ count and a rapid increase in HIV RNA copies and people are extremely infectious at this stage. Often they experience flu-like symptoms; fever, rash, sore throat, myalgia and headache and less commonly meningitis, encephalopathy and neuropathy
This is followed by a partial immune response (an attempt to cure). There is a slight CD4 increase and a drop in HIV RNA copies that falls to a set point which varies from person-person - if it falls to a low setpoint there is likely to be rapid CD4 decline afterwards, but if it falls to a high set point the CD4 decline is likely to be slower
- Asymptomatic HIV infection: can last a few years-decades, people may be asymptomatic or have few symptoms (a period of ‘clinical latency’). A steady decline in CD4 T cells
- AIDS/acquired immunodeficiency syndrome: is the final stage of the HIV infection but doesn’t occur in everyone infected. The majority of people (70-90%) will develop symptoms (once their CD4 count has reached a low point and immune system is damaged); this begins with constitutional symptoms like tiredness, weight loss and progresses to opportunistic diseases (at this point, the person has AIDS) which can lead to death
Name 4 symptoms that can occur in an acute HIV infection
Fever, sore throat, myalgia, malaise
What kinds of opportunistic infections are you likely to start experiencing as your CD4 count continually drops?
Beginning with infections like thrush, can progressively acquire TB, pneumonia, toxoplasmosis and continuously worse infections (that wouldn’t affect those with a healthy immune system as much)
What is the highest age group living with HIV in the UK, what is the highest population?
Which ethnicities of gay/bisexual men and heterosexual men are predominantly living with HIV in the UK?
35-49 yrs old, gay and bisexual men
Ethnicities:
Gay and bisexual men: white
Heterosexual: black African
What is the current HIV treatment and how does it work?
3 drugs: 2 nucleoside reverse transcriptase inhibitors and one drug from a different class (i.e; integrase inhibitors, another NRTI or a protease inhibitor) taken once daily
Halts HIV replication by targeting different areas of the replication cycle so the viral load drops, allowing the CD4 count to grow
What are the benefits of HAART (highly active antiretroviral therapy) for the individual and the population?
Individual: increase life expectancy and by reducing the amount of virus in the blood you reduce the risk of transmission
Population: save health care costs, reduces the overall transmission rate
What did the START study reveal?
A large randomized control trial that revealed that those who started HIV treatment (HAART) immediately had higher CD4 counts (>500) compared to delayed treatments. The immediate HAART also reduced morbidity by 57% and reduced the risk of AIDS by 72%
