HIV Flashcards
_ is responsible for the global pandemic
HIV-1
genotype M is the main one
Subtype B is dominant in the Americas and W Europe
_ is less pathogenic and restricted to W africa
HIV-2
HIV-1 originated from
SIV
How did the virus transfer to humans
bushmeat
HIV is a _
zoonosis
HIV was discovered in
1984
How is HIV transmitted
blood
semen
pre-seminal fluid
rectal fluids
vaginal fluids
breast milk
must come in contact with mucous membrane, damaged tissue, directly injected
HIV is an _virus
RNA retrovirus
envelope
+ RNA
HIV is not stable_
in the environment due to the envelope
Why is HIV a retrovirus
uses reverse transcriptase (high mutation rate) to convert RNA into DNA
key cells HIV infects
Th
HIV requires _ receptors
2
HIV is inseted into
host chromosome, leading to lifelong infection and making treatment difficult
Infection beings with
binding of glycoprotein spikes to primary receptor (CD4) and co-receptor (CCR5, CXCR4)
Reverse transcriptase is
error prone (pathogenicity)
Once viral DNA is formed, intergrase
integrated into the host DNA
CCR5 gene deletion
naturally occuring deletion
CCR5 receptor never reaches the cell surface
homozygotes do not get HIV
heterozygots are long-term non-progressors
HIV disease mechanism
depletion of CD4 T cells
Host response to HIV
fails to contain infection
rapid mutation rate, persistent infection of macrophages and CD4 T cells
patients with HIV
have an increased risk of fungal, bacteral, viral infections due to decreased CD4
viral load is the most important predictor of
how fast CD4 cells are depleated
HIV has a _ latency period
long clinical (no signs or symptoms)
Stages of HIV-1 infection
VIral transmission
primary infection
seroconversion
clinical latency period
early symptomatic HIV
AIDS
Advanced HIV (CD4 cell count <50)
Acute HIV is the third most common cause of
mononucleosis
early signs and symptoms of HIV
lymphadenopathy
oral hairy leukoplakia due to EBV
seborrheic dermatitis
herpes zoster VZV
Kaposi sarcoma is due to
HHV-8
Mycobacteium tuberculosis
higher risk for reactivation
Opportunistic infections (CD4<200)
pneumocystis pneumonia (pneumocystis jirovecii)
CD4<100
toxoplasmosis
HIV testing began targeting
pregnant women
Universal testing is used to detect
HIV before symptoms are present because skink-based testing has failed to identify eary
percent of adults who have been tested for HIV
43%
it takes over _ for lab markers to be positive
a week
the first marker is
HIV RNA (not used routinely)
The 2nd lab marker detected
HIV-1 p24 antigen followed by HIV antibody (used for detection)
You cannot make an HIV diagnosis with
a single test (there are false positives)
3rd generation test only test for
antibodies
the 4th generation enzyme immunoassay
IgM and IgG
Confirmatory test
HIV-1/2 antibody differentation immunoassay
HIV RNA is used
when screening test is positive but follow up test in negative
tie breaker test
diagnose acute or early HIV
staging
monitoring response to ART
diagnosis of perinatally aquired HIV in infants
goal of HIV treatment
help patients live longer by making viral load undetectible
risks of treatment
cost
drug resistance
side effects
(BENIFITS FAR OUTWEIGH THE HARM)
Initiation of ART
started immediately reguardless of CD4 counts
conditions favoring more urgent ART
OPANA
opportunistic infections
pregnancy
acute HIV
nephropathy
advaced disease
ART regimen
never one
give combination to prevent resistance
2 NRTIs plus INSTI
How do we monitor response to therapy
viral load monitoring
virologic supression (<50 copies/mL)
undetectable HIV RNA level within 8 to 24 weeks
Why does treatment fail
adherence
medication adherence for chronic disease is
50%
Prophysalxis it provided for
Toxoplasma
Pneumocystis
people with an undetectable viral load
cannot be tranmitted to others via sexual transmission (u=u)
