L-36

Question 1

What is HIV?

Answer 1

HIV is a lentivirus that causes aids.

Question 2

How is HIV infection spread?

Answer 2

Through bodily fluids

Question 3

What perfect of the population does HIV affect? What percentage of deaths worldwide is HIV responsible for?

Answer 3

• 0.6%

- 3.5% (5.7% in low income countries)

Question 4

What does HIV/AIDS do in the body?

Answer 4

Infects and causes failure of the immune system

Question 5

How long does untreated AIDS take to kill people?

Answer 5

Usually within a year

Question 6

What can new antiretroviral drugs do for patients with HIV?

Answer 6

Delay or even stop progression to aids

Question 7

Why do low income countries have a higher rate of death from HIV/AIDS if there is no cure anywhere?

Answer 7

Low income countries don’t have access to the antiretrovirals that stop the progression from HIV to AIDS

Question 8

What process can be used to isolate viral genomes of patients infected with HIV?

Answer 8

PCR

Question 9

What were the findings of the phylogenic tree of HIV viruses in some different patients

Answer 9

• multiple sequences came from each patient

- sequences within patients are more closely related than those between patients

Question 10

What was the first potential explanation for the variation in viral sequence within patients with HIV? What was the evidence for and against this?

Answer 10

• The patient was infected with multiple viruses.
• multiple sequences + infection could come from bulk source
• pattern of the tree, no explanation for why viruses within patients were closer related than others

Question 11

What was the 2nd (proven) explanation for the variation in the HIV viral sequence? What is the evidence before and against?

Answer 11

• the virus is constantly evolving within a patient
• viral sequences within patients are more similar than those between them, pattern of tree suggests a single point of entry of a virus and then diversification
• patient 91 was an outlier and has virus sequences in two parts of the tree

Question 12

What is the prediction made based off the theory of the evolution of the virus that would prove it to be correct?

Answer 12

If the viruses are changing then if we sample a patient successively then we should see different viral sequences appearing

Question 13

What is the proximate explanation for the evolution of the HIV virus?

Answer 13

• HIV is a lentivirus which is a sort of retrovirus so has an RNA genome
• it infects and damages immune system cells
• it undergoes reverse transcription which is done by reverse transcriptase enzyme that turns RNA sequences back into DNA to insert into the genome
• this is more error prone process than DNA replication so a lot more variants are formed
• the virus is constantly evolving within the host

Question 14

how long does HIV replication take?

Answer 14

20 mins

Question 15

How do we prove if the variation in HIV viral genome is evolution?

Answer 15

• changing the selective pressure by putting a patient on antiretroviral drugs which showed that AIDS viruses from patients on antiretrovirals have a different pattern of variation from those that are not

Question 16

What makes creating vaccines for the HIV virus especially difficult in comparison with other viruses?

Answer 16

HIV is the fastest evolving thing we know of