HIV Virology

Question 1

Where did HIV come from

Answer 1

• 2 distinct HIV Viruses: HIV-1 and HIV-2
  -HIV-1 is related to viruses called Simian immunodeficiency virus SIV found in chimps and gorillas in west Africa
• HIV-2 is closely related to SIV found in another primate, the sooty mangabey
• HIV viruses are thought to have crossed species from primates to humans in Africa in the late 19-20th century (rarer and slower)

Question 2

How did virus jump species

Answer 2

• “bush meat” theory- a hunter was bitten/ cut while butchering an animal
• how SIV transformers into HIV is unknown
• other factors may have triggered the epidemic of transmission: social changes+ urbanisation, unsterile injection, genital ulcer diseases and sexual promiscuity

Question 3

How did virus jump species

Answer 3

• “bush meat” theory- a hunter was bitten/ cut while butchering an animal
• how SIV transformers into HIV is unknown
• other factors may have triggered the epidemic of transmission: social changes+ urbanisation, unsterile injection, genital ulcer diseases and sexual promiscuity

Question 4

How is HIV transmitted

Answer 4

• enters the body through open cites, sores or breaks in the skin, through mucous membrane (anus,vagina, direct injections)

Question 5

Activities that allow hiv transmission

Answer 5

-anal/vagunak interviurse
-injecting drugs + sharing equipment
- mother to child transmission
- transmission in health care settings
- transmission via donated blood or blood clotting factors

Question 6

How does HIV cause illness

Answer 6

• HIV infects cells in immune system such as T helper Cells, macrophages and dendritic cells
• all these cells carry CD4 receptors which allow HIV entry

Question 7

HIV and CD4

Answer 7

• HIV infection causes depletion of CD4 T cells by:
  Direct viral killing of cells, apoptosis of uninflected “bystander cells” and CD8+ cell killing of infected CD4+ cells
• abnormal b cell activation resulting in excess/ inappropriate immunoglobulin production
  -once CD4+ cells fall below a critical level the person is at risk of opportunistic infection and cancers

Question 8

HIV latency

Answer 8

• state of reversible non-productive infection of individual cells
• in the HIV, latency is generally used to describe the long asymptomatic period between initial infection and advanced HIV(AIDS)
• With PCR, it has become clear that HIV replicated actively thought out the course of the infection even during the asymptomatic period
• once HIV virus genetic material incorporated into host DNA, there is no cure as no way to remove it

Question 9

HIV Resistance

Answer 9

• HIV multiple is in body, the virus sometimes mutates and produces variations of itself. Variations of HIV that may develop during the course of taking HIV medicine can lead to drug resistance strains of HIV
• coming HIV medicine are not effective against new drug resistant HIV, HIV medicine can’t prevent the drug resisting HIV from multiplying
• medial adherence: taking HIV medicine every day and exactly as prescribed