lecture 34: diseases and disorders 6: AIDS

Question 1

What is the greatest pandemic ever to affect mankind?

Answer 1

• the global HIV/AIDS pandemic
• each small square represents 2500 people who are HIV positive
• not close to over
• growing pandemic in indonesia due to homosexual behaviour → jakarta, big industry for gay men to pose as female prostitutes, recipients of anal (no protection), once they make enough money fly to thailand to undergo gender reassignment
• china’s infection has exploded, thailand has large numbers
• HIV is spreading
• most infections spreading around seaports where sailors are desparate for sex
• each country on that map has a fantastic story to tell

Question 2

Where did HIV all begin?

Answer 2

• currently 35 million cases of HIV
• currently concered about ~2000 cases of Ebola → ebola comes from fruit bats
• HIV probably first started in gabon
• endemic retrovirus of chimpanzees
• jumps from chimps to humans e.g. hunters

Question 3

How did roger short first come to know about HIV?

Answer 3

• had just arrived in australia from britain
• went to a proffesorship at monash in 1982
• 1984 - dean rang up and said “roger there is this new gay disease that is spreading out in california, give a lecture about this disease, don’t know anything”
• had to learn about it
• royal melbourne hospital - asked about sexually transmitted diseases
• talked to patient - Brett
• what do you want to know?
• ‘gay disease’
• blood test
• flowers
• HIV+

Question 4

Why didn’t HIV wipe out chimpanzees?

Answer 4

• natural protection against STDs
• female chimp only mates when she comes into oestrus
• during oestrus the vulva becomes very distended
• increases in volume by half a litre or so → enormous swelling, with a pair of binoculars you can spot a female chimp in heat from a mile away
• female will only permit copulation by a male when she is in heat
• vagina is cornified and caratinised → extremely difficult for HIV to get in
• natural protection

Question 5

What was the paper RV short publish?

Answer 5

• new ways of preventing HIV infection: thinking simply, simply thinking

Question 6

What was published in 2011 in science?

Answer 6

• “breakthrough of the year: HIV treatment as prevention”
• ART - pill everyday forever
• pretty awful
• become susceptible to other infections e.g. tuberculosis
• HIV is a retrovirus - RNA, through reverse transcriptase, becomes part of your genome
• so hard to get rid of
• even if you are on ART → no symptoms → go off, virus will reappear
• to suggest that the world should go onto ART to prevent HIV, could only have been written by someone who was making a lot of money out of pharmaceutical companies
• how that could get published in america’s leading scientific journal, we’ll never know

Question 7

What is the population of adolescents aged 10-19 with HIV/AIDS by country, Africa (2009)?

Answer 7

• far more females than males
• south africa → almost 300,000
• botswanan student asked girls what they thought their greatest risk was in getting HIV
  
  • greatest risk of becoming infected was being raped by the school master
• how can we account for so many more girls being HIV positive?

Question 8

How does a male become infected with HIV?

Answer 8

• flaccid uncircumsised penis
• erect uncircumcised penis with the foreskin retracted showing likely sites of HIV-1 entry
• epithelium on the inside of the foreskin is very thin, contains many langerhans cells which contain the receptor for HIV
• upon erection, HIV is entering the body through the inside of the foreskin which is being reflected back down the penis
• glans penis has very thick keratin on the outside → protective
• if you washed uncut hands in a bowl of HIV you wouldn’t get it
• male circumcision is a major protective against men getting HIV
• 50% protective
• now major projects to run out male circumcision across the whole of africa
• topical oestrogen keratinises the human foreskin and may help prevent HIV infection
• topical cream that contains oestreol → excreted in urine every day
• weakest natural oestrogen
• if you make it into a cream, you can produce something that keratinises
• oestrogen can increase keratin thickness of the inner foreskin epithelium, potentially forming a physical barrier to HIV entry
• prevention is better than cure

Question 9

What is tenascin-C?

Answer 9

• an innate broad-spectrum, HIV-1-neutralising protein in breast milk
• significance:
  
  • achieving an AIDS-free generation will require elimination of breast milk transmission of HIV-1, as breastfeeding is a cornerstone of infant survival in developing regions
  • antiretroviral prophylaxis considerably reduces postnatal HIV-1 transmission, yet its efficacy is limited by access, adherence, toxicities, and resistance of maternal HIV-1 strains
  • alternative, safe strategies of impeding postnatal HIV-1 transmission will be required to eliminate infant HIV-1 infection
  • in this paper, we identify an innate HIV-neutralizing protein in breast milk, Teascin-C, which captures and neutralises HIV-1 virions via binding to the chemokine coreceptor binding site on the HIV-1 envelope
  • this protein has the potential to be developed as a prevention strategy for postnatal and other modes of HIV-1 transmission

Question 10

What about HIV in sex workers?

Answer 10

• paper in the lancet
• to address HIV in sex workers will need sustained community engagemnet and empowerment, continued research, political will, structural and policy reform, and innovative programmes. but such actions can and must be achieved for sex worker communities everywhere