Showing posts with label molecular clocks. Show all posts
Showing posts with label molecular clocks. Show all posts

Monday 3 March 2014

Why Teachers Should Read ''The Origins of AIDS''

Why learn about AIDS?

I know AIDS has taken the lives of a lot of good people, millions in fact.  I have contributed to charities raising funds for AIDS research, but I have never felt personally concerned about this disease more than about any other (an ancillary benefit of having been a one-woman man for the last 31 years, I suppose).  I’ve never been particularly interested in medicine or biology for that matter.  So what compelled me to read an extensive, detailed study of the history of the virus known as HIV?

I had read a lot of good reports about this book, how it was the truth about AIDS that nobody wanted to talk about.  How many times had I heard that before? Although I’d never read a complete book on the subject, I had a hunch that this might be a book worth reading.  Not because I was interested in AIDS per se, but because its spread had become such a cultural and educational phenomenon.  

Has AIDS education failed?

How many times have you heard it said that what we need is “AIDS education”?  So after 30 years of AIDS education and an intense media blitz, how is it that someone like me, who can read and pay attention, is still so ignorant about this disease?  AIDS, because it has been described as an epidemic beginning in 1981, is an example of how the population we are all part of is educated on a mass level.  My conclusion is:  very poorly.

How the media covers AIDS

Over the years, every time I encountered a discussion of AIDS it was invariably someone announcing that someone else was wrong about it’s etiology.  The news media was only interested in an AIDS story if it involved a celebrity, a scandal or a surprising and dramatic turn of events.  It was only news if someone was claiming an unexpected breakthrough or a cover-up.  Almost as soon as I had learned that AIDs was caused by a Human Immunodeficiency Virus, I heard someone claiming that AIDS (Acquired Immune Deficiency Syndrome) was not caused by HIV.  I remember “learning” that the source of AIDS was homosexual men.  In fact, in the early 80s a homosexual flight attendant from Quebec was identified as “patient zero.”  This guy not only had AIDS, and spread it everywhere his airline company flew, but he was reported to have had 200 to 300 different sex partners per year.  Great fodder for homophobic evangelicals.

This book aims to teach!

So why should teachers in particular read this book?  I have to invent a word to answer this question:  because it’s teacherly. “Pedantic,” which literal means “like a male teacher,” has become a strictly derogatory term.  “Educational” and “informative” are the kinds of descriptors that can be applied to any book.  “Pedagogical” would be misleading in that the word would imply that the book is about education and teaching (and etymologically about children).   By teacherly, I mean that the book is an obvious, careful and patient attempt to teach the reader.  It worked for me.  I learned a lot.  In fact everything I know about AIDS and HIV--and by this I mean everything that isn’t muddled, foggy and contradictory in my brain--I learned from this book.

What we need to learn

I’m not saying that the book answered every question about AIDS; in fact, the author Jacques Pepin (not to be confused with the chef) sounded almost apologetic that the book was about the early history and origins of the disease.  Like the author, I agree that in order to understand AIDS we need to know where it came from and how it evolved.  Pepin’s prose style isn’t literary or poetic, and he expects you to hang in there while he talks statistics, divisions and percentages and does the math, but every step of the way he tells you clearly and frankly what he is doing, and how certain and precise his conclusions are and aren’t.  Every time a concept or procedure is introduced that a lay reader might not understand, he takes the time to clearly explain and lay out the groundwork of the methodologies used to  reach his conclusions.  So yes, dear reader you are going to learn about “iatrogenic” and “nosocomial” diseases (meaning those caused by doctors and treatment, and in a hospital), and “molecular clocks” used to tell us how long a virus has been around, and “phylogenetics” (the study of the evolutionary diversification of organisms).  The book has a lot to say (I mean teach) about colonial and neo-colonial Africa and, in his admittedly most hypothetical and controversial claim, about how the spread of HIV from Africa to Haiti to North America was significantly enhanced by the establishment of plasma banks where poor people and prisoners could sell the plasma extracted from their blood.

So where did AIDS (Acquired Immune Deficiency Syndrome) come from?

It is the result of a virus, specifically the Human Immunodeficiency Virus (HIV).

Aren’t there some people who have HIV and never develop AIDS?

This is where the story starts to get complicated, but at the same time its pretty simple.  To answer this question we need to answer the next question first.

Where did HIV (Human Immunodeficiency Virus) come from?  Answer: SIV.

HIV is the human form of SIV; that is, Simian Immunodeficiency Virus.  “Simian” refers to monkeys and apes.  Long story short:  AIDS comes from monkeys.  No, not homosexual, drug-addicted monkeys.  In fact, the form of HIV which has killed millions can be traced to the common chimpanzees of central Africa.  SIV has existed in ape and monkey populations for hundreds of years.  The divergent forms of HIV which have now been identified (yes, there are many kinds of HIV)  can be traced back (using “molecular clocks” and “phylogenetics”) to different times and places.  HIV-2 came from a specific variety of SIV found in apes in eastern Africa.  HIV-2 is a slow developing form of the virus.  People seldom die from HIV-2.  HIV-1 is the killer virus; the typical time span between contracting the virus and the development of AIDS is 10 years.  There are 8 identified, divergent strains of the HIV-1.  HIV-1 group M (for Main) accounts for 99% of infections and is the cause of the pandemic.  Every strain of the HIV virus is different in terms of rate of mortality and ease and type of transmission. In general, the chance of sexual transmission of HIV is about 1 in 1000.  (In other words, the statistical expectation is that if a man with HIV had sex 1000 times, the virus would be transmitted once.  However, if the man also had an STD and/or was un-circumcized the possibility of transmission would increase.)  The transmission rate through blood (transfusions, shared needles, etc) is 1 in 10.

How did HIV-SIV enter the human population?

Simple answer is that African tribesmen hunted and cooked monkeys.  It is easy enough to imagine people being bitten and scratched by monkeys.  By back tracing the various strains of HIV now in existence the virus (which was SIV and became HIV) entered the human population at 8 different points/occasions some time between 1900 and 1930.  For convenience of reference Pepin gives 1921 as year one of HIV.  Under “normal” circumstances the 8 people who had contracted the virus would have died within 10 years and that would have been the end of the virus and the disease--which brings us to the next question.

How did HIV-AIDS become an epidemic?

This is really the question that The Origins of Aids sets out to answer.  The answer lies in the geo-politics of colonial and neo-colonial Africa, the sex trade, African customs and traditions, industrialization and urbanization, and, in a detailed exposé of ‘how the road to hell is paved with good intentions,’ how attempts to combat sleeping sickness, malaria, tuberculosis, leprosy and various STDs through mass inoculations with unsterile needles led to HIV-1 M, which infected only one person in 1921, being transmitted to millions world wide. 

No doubt if he stumbled across this blog, Dr. Pepin would tear his hair out reading my clumsy, facile attempt to summarize his work.  I recommend you don't depend on this trailer.  If I've piqued your curiosity, read the book.   

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