Lecture 19: HIV

Question 1

What are the subfamilies of retroviruses

Answer 1

Oncoviruses (HTLV-1, HTV-2)

Lentiviruses (HIV-1, HIV-2)

Question 2

What are characteristics of aids

Answer 2

HIV positive, less than 200 CD4 indicator disease

Question 3

Can you have HIV without aids

Answer 3

if you have HIV it does not mean that you have aids, aids is a syndrome you contract after becoming infected with HIV and become suspetable to the infection (immune system has to become compromised as virus has replicated and destroyed your CD4 cells doesn’t happen to everyone who contracts HIV if they are on appropriate management

Question 4

What are characteristics of retroviruses

Answer 4

enveloped, positive-strand RNA virus, encodes reverse transcriptase

Replicate through a DNA intermediate, then back into RNA

The DNA copy is integrated (why it was so hard to treat) into the host chromosome to become a cellular gene

Question 5

Who discovered retroviruses

Answer 5

HIV-1 was discovered in 1918 by Gallo and Montagnier

Subsequently, HIV-2 was isolated in West Africa

Question 6

____ of HIV+ live in Africa

Answer 6

67% (7.5% of world)

Question 7

What is HIV presented in

Answer 7

blood (or fluids contaminated by blood and serum)

Semen

Vaginal fluids

Question 8

What are factors that increase infectiousness in HIV

Answer 8

Primary infection: high viral load

Late-stage: high viral load

Genital tract infections: mucosal breech and recruitment of inflammatory cells

Question 9

What is the biggest determinate of HIV

Answer 9

Host related factors

Question 10

Estimated ____ of people dont know they are infected with HIV

Answer 10

25%

Question 11

What are the top risks of acquiring HIV

Answer 11

blood transfusion

mother to infant: 1 in 4 (with no treatment)

mother to infant with treatment

needle-sharing with IV drug use

anal

needle stick injury

Question 12

How does HIV replicate

Answer 12

The mushroom shaped gp120 (protein on surface of HIV virus) of HIV interacts with the CD4 receptor surface molecule expressed on T-helper lymphocytes and cells of the macrophage lineage. through binding and fusion

3. Reverse transcription: synthesizes a complementary DNA
4. Integration: into our genome by integrate; Once integrated, viral DNA is transcribed like other host genes
5. Replication: each copy contains approximately five errors or mutation
6. Assembly
7. Budding

Question 13

How does HIV enter

Answer 13

by fusion with the cellular envelope

Question 14

HIV infection of CD4 lymphocytes results in

Answer 14

cell death

Question 15

___ are primarily responsible for cell mediated immunity

Answer 15

CD4s

Question 16

As CD$ cells are lost, ____ and ____

Answer 16

opportunistic infections and malignancies occur

Question 17

What is the course of aids with no treatment

Answer 17

High HIV load in blood

Question 18

When does aids develop when

Answer 18

any of a number of signs of CD4 depletion occur

Question 19

What are lab aspects of HIV

Answer 19

1. Serology:
   - screening tests for antibodies to a number of viral antigens by enzyme immunoassay
   - confirmation using western blot
2. Immunologic studies: CD4 counts
3. Viral load testing: PCR quantification of RNA in plasma
4. Resistance genotyping:L looking at the sequences of the genes in the HIV to see if there are mutation that cause resistance

Question 20

what is a BioRad Geenius

Answer 20

Differentiates HIV1 and HIV2

Removes subjectivity

rapid (30 min)

Question 21

What are the goals of HIV therapy

Answer 21

Maximal and durable suppression viral load

Restoration or preservation of immune function

Improvement in quality of life

Reduction of HIV morbidity and mortality

Preservation of future treatment options

Question 22

Why is it important to suppress the viral load in HIV

Answer 22

now with some therapies we can drop someones viral load to the point where it is undetectable, if you are undetectable it is not sensitive enough to be picked up on a lab test and you cant transmit the virus when you are undetectable

Question 23

Why is it important to preserve future treatment options for HIV

Answer 23

get simple, less drugs, less time a day makes people compliant to stay on drugs if they come off they could become resistant

Question 24

What is the treatment for HIV

Answer 24

anti retro-virals

specifically nucleoside analogs (reverse transcriptase inhibitors)

lots more options now too ex. protease, fusion and integrate inhibitors

Question 25

What did treatment for HIV look like in the past

Answer 25

there were only 3 types of nucleoside analogs
(ALT, 3CT, DDI)

do you treat right away: only 3 options could become resistant if not compliant

so often would wait for them to absolutely need to the drug

Question 26

What is HAART

Answer 26

highly active anti retroviral therapy

Question 27

When was there a big drop in HIV

Answer 27

1997 as appropriate therapy (HAART)

Question 28

What does the risk of infection in a needle stick exposure depend on

Answer 28

stage of patients disease (primary is worst, or terminal without management)

How much blood (hollow (blood inside) vs. solid, gauge of needle, aspiration vs. injection)

Question 29

What to do if you have a needle stick exposure

Answer 29

report to occupational health

Confirm patients status

document your status (for insurance purposes, prove that you weren’t hurt before exposure)

begin antiviral phorphylaxis (take with 72 hours of exposure)