MIC test 1 lecture 6 (9/12) Flashcards

• when babies w/ HIV were sick, they originally had no idea it was HIV
• this was beginning of epidemic, adult AIDS has already been described
• did not know for babies it was the same thing adults were having

1 early challenge - determine whom infants were being infect by. source turned out to be mother

• many mothers were asymptomatic, baby born -> dev AIDS -> died, all while mother did not know she had aids (bc was asymptomatc)
  • bc asymptomatic periods in adults can last several years (avg = 7 yrs)
• developed much quicker in babies (weaker immune system)
• important to rule out that babies got from household members
  • didnt know if casual contact could transmit disease

once determined that babies were infected by mothers -> became important to determine the HIV status of the mother

• HIV testing became possible in 1984 (1 yr after virus identification)

before ARVS, chance of untreated HIV mother to transmit virus to infant = 20-30%

Challenges to determine whether AZT could reduce mother-infant HIV transmission:

• some thought AZT too harmful/toxic shoudl never be used to treat AIDS. common medical practice at time against giving pregnant women any type of drug

if mother treated, decrease probability of infection to baby

• then treat baby once born to get rid of any viral load = dont get virus

exposure - being exposed to virions (birth, sex, needle use, etc.)

• few virions in your blood, whether or not leads to acute infection, is a probability
• exposure by itself does not necessarily = infection

NOT HIV+ UNTIL PASS INTO ACUTE PHASE

• 2019, 70,630 drug ODs occurred in the US
• 2020, 91,799 drug ODs occurred in the US (inc by 31%)
  • opioids involved in 68,630 OD deaths in 2020 (74.8% of all OD deaths)

• code red theories
  • scientifically plausible but outside the mainstream
  • professor denied link btw HIV/AIDS
    • believed HIV could not cause what was happening
    • denies HIV caused AIDS
    • leader in south africa believed it, stopped a lot of medical practice against HIV/AIDS
      • then had highest death rates of HIV/AIDS

• tested various blood samples from over the world (mostly africa) from ppl who were suspected to have died from HIV/AIDS
• for each sample, could connect to time + geographic location
• turns out HIV has very high mutation rate
  • mutates within an individual
• found that republic of congo was focus of early transmission and the source of pre-1960 pandemic viruses elsewhere
• was straightforward to find where HIV came from
  • HIV family trees to track transmission
• HIV has 10,000 genes in genome
  • collected sequences from 814 ppl (blood test) that were HIV+
  • determined genetic sequencing -> made family tree of HIV
    • found relationship
    • matched to geographical place
    • showed original person w/ HIV lived in 1920s and in africa (rep. of congo area)
    • confident abt this
    • = first person w/ HIV

• populary story, but UNTRUE:
  • found sexual connections among 9 of 13 men diagnosed with KS or PCP thru links of an air canada flight attendant
  • patient 0, airline steward, gay, sexually active
• what think actually happened:
  • 1970s and patient 0, HIV-1 genomes illuminate early HIV/AIDS history in North America
  • believe came to US in 1970s
  • studied samples from blood banks, found since 70s
  • abstract:
    • found in 1970s thru studies and even before in the caribbean
    • earliest movements within US unknown
    • screened >2000 1970s serum samples, full genome snapshot showed that US HIV epidemic had genetic diversity in the 1970s, but also provides strong evidence for its emergence from pre-existing caribbean epidemic
    • estimate jump to US around 1970 and believe at first in NYC (from the caribbean?)

• chimps harbor HIV-like retroviruses
  • didnt know until late 90s-early 2000s

• ancestor to HIV-1
• in africa >40 non human primate species are infected w/ various SIV (simian immunodeficiency virus) strains
  • most cases are chronic + asymptomati
• these SIV like infections have been observed in 2 of the 4 subspecies of chimpanzees (pan troglodytes)
  • these SIV cps are themselves derived from other old world monkey species
• diff HIV-1 groups: M, N, O, P, each derived from separate introductions of SIV into humans

what i wrote

simian = monkey

various SIVs in chimp subspecies

many times chimps are chronically infected b ut never develops AIDS disease, and most dont eliminate the retrovirus

know that jumps from chimps -> humans happens occasionally

this likely happens in the 1920s ish

then 1920s-1981 = silent spread of HIV