Lecture 6: HIV Flashcards
What kind of cells does HIV invade?
CD4 T helper cells
Dendritic cells
Monocytes
When does a person have AIDS?
CD4 count < 200 cells/mL
OR
Presence of any AIDS defining condition
What is the origin virus of HIV?
SIV (Simian)
Where did HIV originate?
Kinshasa (Northernish africa)
Where did HIV first hit the US?
NYC 1970s
When was AIDS identified and termed?
1981/1982.
What was the first US case of AIDS in a female?
Female partner of a known HIV infected in 1983.
When was HIV actually discovered?
1984
AKA it came after AIDS was defined.
When did we start having HIV blood tests?
1985, a year after HIV was identified and 4 years after AIDS was identified.
When did HIV start declining?
1995, as we developed an oral HIV test.
Where was AIDS the leading cause of death in 1999?
Africa.
4th in the World.
When did generic HIV drugs start rolling out?
2001
When was PrEP made?
2012
When did blood donation rules finally change in regards to HIV?
2015
Where in the US is HIV most prevalent?
The south
Who does the WHO define as the greatest populations at risk for HIV?
Men who have sex with men
Transgender
IVDU
Sex workers
Heterosexuals
Healthcare workers (needlestick transmission is 3 in 1000)
What is HIV’s mode of transmission?
Blood
Semen
Pre-seminal fluid
Rectal fluid
Vaginal fluid
Breast milk
Contact with mucous membranes/damaged tissue
Direct injection
What is the most common entryway for HIV transmission?
Anogenital mucosa
aka most common risk is receptive anal intercourse.
How is HIV NOT transmitted?
Saliva
Sweat
Tears
Vomit
Urine
Nasal secretions
What is the rarest HIV transmission rate?
Blood transfusions in the US. 1 in 1million.
What is the highest HIV transmission rate?
Mother to child. 13-40%
How does HIV work? (7)
- Fuses to host cell
- Forces entry, injecting HIV RNA, reverse transcriptase, integrase, and viral proteins.
- Viral DNA is made by reverse transcriptase.
- Viral DNA transports across the cell nucleus to integrate with the Host DNA.
- New Viral RNA is made as part of the cell’s genomic RNA.
- New viral RNA and proteins move to cell surface, forming an immature HIV.
- Virus is released and protease cleaves to create a new mature virus.
What exactly does HIV interact with on a cell surface?
gp120 on virion envelope + T-cell coreceptor (CXCR4) via a CCR5 co-receptor
What is transinfection?
A dendritic cell with HIV bound to it transfers it to CD4 T cells.
What are the stages of HIV infection?
Viral transmission/HIV acquisition
Acute HIV infection/Acute retroviral syndrome (Symptomatic stage)
Chronic HIV infection (AIDS! Not always symptomatic)
Advanced HIV infection (CD4 <50)
What are the 4 stages of an acute HIV infection?
- Viral penetration of mucosal epithelium
- Infection of submucosal CD4 T cells, dendritic cells, and monocytes.
- Spreads to lymph nodes
- HIV viremia
What is an acute retroviral syndrome?
A nonspecific viral syndrome with symptoms identical to the flu.
Spontaneous resolutions.
Asymptomatic post syndrome for a while.
When does acute retroviral syndrome occur?
Usually during acute HIV infection.
What are the key systems to review in your PE for HIV suspicion?
HEENT
Lymphatics
Abd exam (HSM)
Skin
What people should be tested for HIV?
Known or suspected sexual or hematologic exposure
Promiscuous sexual history
IVDU
Accidental needlesticks
Pregnancy
Recent STI
Note:
CDC recommends routine screening from 13-64 at least once in your lifetime.
What are the tests available for HIV?
ELISA test
HIV Rapid antibody test
Serum Western Blot
Serum, p24 antigen
Serum PCR
CD4 Count
Serum Viral load
What lab test is primarily indicated for infants?
Serum HIV DNA PCR
What is the primary lab test for HIV?
ELISA
What is the next step after an ELISA test?
Western blot to confirm
When do you order Serum viral load tests?
Either prior to HIV tx or very late.
Viral load is not as indicative because it drops in the latent period.
When is a p24 antigen test indicated?
ASAP post infection
What positive lab test indicates a provider to NOT RX abacavir?
Human leukocyte antigen-B*5701
What should all positive HIV patients be offered?
ART!!!!
What is the CDCs recommendation on safe sex?
Counsel all patients not to exchange bodily fluids unless they are in a long-term mutually monogamous relationship with someone who has tested HIV antibody negative and has not engaged in unsafe sex, injection drug use, or other HIV risk behaviors for at least 6 months prior to or at any time since the negative test.
What is used to reduce the risk of HIV transmission to uninfected partners?
Early ART
What is used to reduce an HIV negative person at risk for infection?
Pre-exposure ART Prophylaxis
What is used to reduce HIV infections once exposed?
Post-exposure prophylaxis
What is something people undergoing elective surgeries can do to reduce HIV transmission?
Donate their own blood prior to surgery.
What is PrEP? What does it consist of?
It is PRE-exposure prophylaxis.
It is targeted to high-risk patients and uses Tenofovir/Truvada, which is an NRTI.