HIV/AIDS

Question 1

what year did HIV appear and where?

Answer 1

1981, LA

Question 2

how many cases were documented within a few months?

Answer 2

5

Question 3

who were the first cases of people to be infected?

Answer 3

young homosexual men who appeared healthy except for fever, weight loss and rare infections

similar reports from all over the country being released

Question 4

extremely rare and aggressive clusters of _____ sarcoma were an initial symptom

Answer 4

Kaposi’s

Question 5

how many cases were reported in LA by the end of 1981?

Answer 5

270 reported cases of severe immunodeficiency among homosexual men

Question 6

what were the risk factors at the start and later?

Answer 6

start = number of sexual partners and recreational drug use,
later = haemophilia

Question 7

who was one of the 1st UK citizens to die from AIDS?

Answer 7

Terrence Higgins

Question 8

____ million people live with HIV globally

Answer 8

36.7

Question 9

___% are unaware they have HIV

Answer 9

30

Question 10

____ new infections are transmitted each year

Answer 10

fewer

Question 11

___% prevalence in southern/eastern africa

___% prevalence in swaziland

Answer 11

7.1, 27

Question 12

sufferers in developed countries have better access to treatment,
UK → __% of sufferers are on antiretroviral drugs compared to __% in south east africa

Answer 12

96, 54

Question 13

how is HIV transmitted?

Answer 13

→ blood and blood by products
→ semen
→ vaginal fluid and secretions
→ any body fluid that has mixed with infected blood
→ sometimes breast milk and across the placenta

(not saliva)

Question 14

describe the asymptomatic period of HIV

Answer 14

when first infected, flu like symptoms persist for around 6 weeks,
after this, asymptomatic period can last up to 15 years

Question 15

symptoms of AIDs and compromised immune system include:

Answer 15

shingles, lip warts, muscle wastage, PCP (Pneumocytis pneumonia), kaposi’s sarcoma, thrush

Question 16

how does combination antiretroviral therapy work

Answer 16

→ controls viral replication
→ allows immune system to recover
→ allows infected individuals to live healthy productive lives (but is not a cure)
→ gives hope for control of HIV spread

Question 17

why was the UN ‘fast track’ treatment scheme too optimistic about HIV decline?

Answer 17

treatments are expensive

Question 18

what does antiretroviral treatment comprise of?

Answer 18

fusion and entry inhibitors:
(so the HIV vision can’t enter cells)

intergrade inhibitors:
(prevent HIV DNA becoming integrated into hosts DNA)

protease inhibitors:
(prevent formation of new viruses)

Question 19

describe features and functions of a HIV virion

Answer 19

→ retrovirus with 2 mRNA strands
→ reverse transcriptase and integrase enzymes incorporate viral genome into hosts DNA
→ protease enzymes helps form new viruses
→ envelope with GP120 and GP40 that bind to CD4 receptor on host cells

Question 20

viral load =

Answer 20

amount of HIV RNA copies per ml of plasma in blood

Question 21

acute phase 0-12 weeks after infection (viral load) =

Answer 21

rapid increase in viral load

subsequent drop as immune system responds

Question 22

chronic phase 12+ weeks (viral load) =

Answer 22

slow increase in viral load over years until threshold of AIDS is reached
(acute → chronic → aids)
when viral loads reaches a certain critical point a person has AIDS

Question 23

acute phase 0-12 weeks after infection (T cell depletion) =

Answer 23

sudden drop in lymphoid and circulating T cells

T cell count recovers (immune system responding)

Question 24

chronic phase 12+ weeks (T cell depletion) =

Answer 24

slowly declines as viral load increases

Question 25

what is the result of a drastic decline of T cells in the gut?

Answer 25

leaves it vulnerable to attack pathogens

Question 26

what is the T cell count per mm3 when AIDS has been reached?

Answer 26

200

Question 27

describe the action of HIV virus

Answer 27

CD4 receptors = essential for T cell function

T helper cells express CD4 receptors to aid binding of macrophages and to stabilise antigen presentation

HIV virion binds to CD4 and often its co receptor (CCR5)

HIV kills T helper cells in order to replicate inside them
→ eventually there are not enough T helper cells to activate B and T cells to elicit an immune response

most strains of HIV require a CCR5 co receptor to enter T cells

Question 28

what position is the mutation in CCR5 gene that prevents HIV binding?

Answer 28

32

Question 29

what might contribute to the european population having a lower HIV infection rate?

Answer 29

greater frequency of the CCR5 mutation that prevents HIV binding