HIV and AIDS: A Question of Causation

A recent controversy has sprung up around the decision of the journal Medical Hypothesis to publish a paper by Peter Duesberg, a famous critic of the dominant medical belief that HIV causes AIDS. Several websites are dedicated to refuting the "HIV causes AIDS" hypothesis, including Heal Toronto. Millions of reasonably intelligent people have become highly skeptical of HIV as the cause of AIDS.

The problem goes back to the basic issue of causation -- specifically disease causation. Koch's postulates for establishing microbial disease causation include:

1. Isolate the organism from every case
2. Propagate in pure culture in vitro
3. Reproduce disease by injecting the organism into a suitable recipient
4. Re-isolate the organism
__microbiologybytes

These postulates have served quite well over the years, but for some microbial diseases they have proved insufficiently powerful to establish causation. Variations in microbe virulence and in host susceptibility can complicate the establishment of causation.

A more subtle set of postulates for establishing genetic virulence in  more ambiguous situations, have been dubbed the "Molecular Koch's Hypotheses"

1. Identify gene (or gene product) responsible for virulence determinant
2. Show gene present in strains of bacteria that cause the disease
3. Not present in avirulent strains
4. Disrupting the gene reduces virulence
5. Introduction of cloned gene into avirulent strain confers virulence.
6. The gene is expressed in vivo
7. Specific immune response to gene protects
__microbiologybytes

In the case of HIV / AIDS, the classical Koch's Postulates cannot be tested ethically, since intentionally injecting a human with HIV might easily lead to charges of attempted murder against the researcher.  Of course, not even Duesberg himself is likely to be so reckless as to inject himself or others with HIV intentionally.   Which may be one way of measuring the limits of skepticism for this particular hypothesis.  Is the skeptic willing to inject himself with HIV?

At one time, Peter Duesberg was better known as a leading cell biologist and discoverer of the first true human oncogene, src, in 1970.  A long-time tenured professor at UCB and a member of the NAS, Duesberg's vocal skepticism of the HIV to AIDS hypothesis has, since his 1996 book "Inventing the AIDS Virus", placed him well out of the mainstream of biomedical thought.

It is not the intent of Al Fin Epidemiiologists to refute Duesberg's various lines of arguments in a blog post.  Rather, it is the intent of this posting to take a short peek into the phenomenon of human belief itself.   Duesberg's various lines of attack against the HIV to AIDS theory have been sufficient to establish strong doubts in the minds of large numbers of intelligent thinkers. 

Al Fin Epidemiologists do not accept Duesberg's arguments as convincing, but then Al Fin Epidemiologists are trained to go to root issues when determining the likelihood of an argument -- particularly an argument dealing with disease causation.   For Al Fin Epidemiologists -- unlike most people -- the question is not one of belief.  It is a question of likelihood, and the most likely routes to efficacious disease therapies and cures.  These are things that can be tested -- or falisified -- as Karl Popper would put it.

Humans are prone to "beliefs", which may or may not be well supported by testable facts or observations.  Humans are easily seduced by "reason and rationality" into forsaking empirical testing of apparent "facts".   How much time is wasted in the media, in congress and parliament, in the social sciences, and in dorm rooms and homes -- on arguments that are not formulated to produce testable hypotheses? 

Instead of bullishly "believing" or "disbelieving", humans should always be asking, "How can I test that assertion?"  If assertions, assumptions, and lines of argument do not lend themselves to testing, they are essentially a waste of a practical person's time.

That is how Al Fin Epidemiologists view Duesberg's arguments over the "HIV to AIDS" hypothesis.  Worse than Duesberg's arguments, are the "meta-arguments" that spring up over Duesberg's original arguments.  These meta-arguments then spawn their own "meta-meta-arguments" in a recursive explosion of wasted hours, days, weeks, months, and years.

What can be tested?

If HIV infection leads to low CD4 cell count, and if low CD4 cell count is associated with much higher incidences of PCP pneumonia, Kaposi's sarcoma, CMV, and a host of other low-immunity associated and opportunistic infections and malignancies, these associations lead directly to testable hypotheses.

If a rebound to higher CD4 cell counts after retroviral treatments is associated with remission from opportunistic diseases, further falsifiable hypotheses can be generated.

In fact, the pertinent level of testable argument, scientifically, lies far away from most of Duesberg's arguments.  That is the main problem that Al Fin Epidemiologists have with Duesberg's arguments -- not his skepticism.  Al Fin applauds skepticism wherever it is productive of meaningful falsifiable hypotheses.

Humans in advanced, High IQ societies are not being taught to use their rationality, their judgment, their discriminatory powers of mind.  This leads to lifelong adult-children, incompetent on many fronts, and ineffectual in determining basic probabilities, likelihoods, and wise choices of everyday life.