If we get to that stage, which we’re not at yet, we
then have to not overprescribe it. The same thing
happens again and again. Many models of this that
have already existed throughout history, various
treatments for malaria, have gone through this
process, over the last several hundred years. The
overuse of chemicals that were identified as
antimalarial, quinine, or chloroquine, each one of
them gets replaced, because use of them results in
Plasmodium becoming resistant. In fact, the most
effective antimalarial is currently called artemisinin.
When it was first developed, it was recommended
that it shouldn’t be used as a monotreatment.
The problem is that it does get used as a
monotreatment. As a result, we have seen for the last
few years, almost a decade now, the development of
resistance to artemisinin. It’s such a complex
ecosystem: it isn’t just a pure science. It is pure
science combined with the commercial imperative to
turn antibiotics into drugs, and then the distribution
of those drugs, and then the prescription of those
drugs, and not using them in ways which are going
to encourage the development of resistance.
Leslie Orgel, a great chemist, came up with a set of
rules, and Rule Two, Orgel’s Second Law, is
‘Evolution is cleverer than you are’. It’s true.
No matter what we do, bacteria are going to outevolve
us. So, we have to be smart in developing the
right drugs.
SG: The flip side of the argument refers to
the epidemiological utility of genetic
modification, such as the use of the CRSIPR
gene-drive to combat malaria. The editing
technique alters the mosquito ‘doublesex’
gene, leading to female mosquitoes who
inherit the modification becoming
increasingly sterile.
The potential eradication of the entire
mosquito population opposes Darwin’s very
idea of natural selection. Do you think
Orgel’s Second Law applies here too, if we
try to predict the success of such an outcome?
Dr Rutherford: Humans have a bad track record for
eradicating anything. Whenever we’ve tried to wipe
out, or sterilise, a species, what we find is that
Orgel’s Second Law kicks in. We’ve had some major
successes, we’ve eradicated smallpox, almost
eradicated polio, but our history of using
interventions to eradicate diseases or invasive
species is really bad.
Part of the problem is that medical interventions
don’t involve evolutionary theory enough. When
you wipe out a tier of an ecosystem, it will be
replaced. Other organisms will find that niche and
exploit it.
One of the reasons we think that malaria evolved is
due to humans clearing plantations to grow yams,
thus generating lots of stagnant water, which gets
populated by mosquitoes and subsequently the
Plasmodium that comes with it. So, we must be
really careful and cautious about this type of
intervention. Using the precautionary principle is
really important. If we go gung-ho about these
things, we inevitably mess it up. If we go in with as
much information as we can, sometimes we can be
overcautious.
Ask microbiologists, because when people start
talking about genetic modification to eradicate
diseases, microbiologists start laughing, because
of the naivety about how evolution works,
particularly with fast reproducing single-celled
organisms.
Jurassic Park got it right. Life will find a way.
We’re really bad at eradicating species
deliberately, unless we hunt them to extinction.
In general, evolution is smarter than us.
Sachi Gwalani