Re: diseases and immunity. My (long) summary

Domingo Martinez-Castilla (
Fri, 12 Jul 96 05:54:02 GMT

What a thread! More than a month, and still going, after spawning several
others. From disease, to domestication, to comparative agriculture, to
methodology, to philosophy of history, and the very important issue of the
memories of disease, all flavored by the tasty informality and common
disregard for references (me included, of course) of a self-respecting

Thus, after keeping an eye for the last (very few) days, I want to make my own
summary, before I forget several important points. I have gone back to old
notes and references and even to the library (trust me), because among many
things this discussion has rekindled my almost dormant interest in history.
Allow me, please, to indulge in some reflections and invitations. (I will
include some useful references at the end.)

First, what is my point? In spite of my not taking part in the Memory of
Plague sub-thread, the very title of it (thanks, Mr. Tillinghast, for
bringing it up) rekindled the fire that started my interest in the area, back
in 1992 --the 500 year occasion.

My previous work had been in agricultural development, in many areas of Latin
America (especially the central Andes, my home) and a bit of Africa as well. I
have always worked along with people of biological disciplines (animal
scientists of all persuasions, agronomists, geneticists, etc.). A conviction
grew that the very extensive body of technical knowledge available in the
developed world was of little immediate use to achieve agricultural progress
in most tropical agriculture settings. However, I have always sustained that
the systematic research methodology is something everybody could and should
use. In other words, we need more basic research, and not too much blind
adaptive technology. (These of course, are generalizations with many

A second point, closer to home, was the failure (by design or by omission) of
over 150 years of republican (as opposed to colonial) governments to
incorporate the massive indigenous populations into the building of many Latin
American nations, not to mention the smaller populations displaced and
encroached by immigrant peoples, in the temperate areas of the Americas.
Thus, my interest in the past was always driven by the problems of the present
and the need for a better future. Basically, it was impossible for me to
understand all those problems without understanding why they came to be in the
first place.

Evidence exists that agriculture in many areas of the Americas was very
advanced for any standards. In the Andes, it is generally accepted that
agriculture production and distribution (through time and space) had been able
to feed all the people for at least the last 75 years before contact (no data
before that). (At least in the Andes, there is almost no relying on hunting
and gathering for food.) The question is, then, what happened? It seems very
clear that today's gross agricultural production in that area is lower than
500 years ago.

My working hypothesis is loss of technology, due to the very fast loss of
population, due in turn to the coming of epidemic diseases. Here, I share the
point of view that the "arrow of disease" (to use Jared Diamond's words)
pointed basically one way as a consequence of the presence of abundant
domestic ungulates living symbiotically with humans in Eurasia, which have
been traced as the original carriers of infections that became epidemic when
those populations became connected through commerce and war. I also share the
view that domestication depends more on the behavior of the animal or plant
than in any human factor (from my trip to the library, I found that all those
potentially agricultural species mentioned in this thread as domesticable or
in the process of domestication are never treated as such, but rather as
"under confinement"). I also share the view that very few animals and plants
lend themselves to true domestication (I will not argue with the very recent
successes of domesticization of some pets and decorative plants and animals,
thanks to heavy investments possible only in affluent societies).

If all that proves true, a first conclusion would emerge: domestication and
hence epidemic disease would have as their causes purely natural, non-human

Regarding disease, I think it is important to establish the difference between
acute epidemic diseases (e.g. smallpox), that kill or immunize very fast, and
endemic diseases (e.g. tuberculosis), that take their toll for long periods of
time. A hypothesis that needs to be tested is whether epidemic diseases may
cause the development of any genetic resistance to them, being both acute and
recent (no matter if we are talking about 6000 or 1000 years). A reasonable
null hypothesis is that they do not. Also, if it is proposed that genetic
variability (a larger genetic pool) may suffice for a population to better
resist epidemic diseases, this will have to be proved. I have not seen
evidence on that respect. The null hypothesis will have to be, again, that
genetic variability is not important given the young age of most epidemic
illnesses. (MB Williams presented a historical case supporting this view.
There are others.)

This brings the "linearity" thing, which I introduced rather carelessly and
did not pursue. We have two contending ideas here: progress as a given, or
progress followed by "recessions" and overall destruction of "the fabric of
society" for different reasons. Man at the top of everything and as the peak
of evolution versus man as one more player in the natural history of this
planet, and subject therefore to strong biological forces. And also the
competing views of human history as a succession of ever more complex and
"advanced" societies, versus the succession of competing paradigms that may
develop separately, clash, and then become some new paradigm, and not allowing
easy judgment values ("better", "advanced", "behind") between them. I am not
talking here about cultural relativism, but rather historical relativism. I
do know this to be a complex issue requiring quite more elaborate explanations
than this paragraph, but I believe it may be worth exploring (this is a task I
impose unto myself, not the participants in this thread.)

The "Memory of plague" issue is also very important, I believe, to understand
the prostration of many indigenous peoples in the Americas and perhaps
Australia (I know very little about how current aboriginal peoples perceive
their contact with the West). These continents have in common the dubious
privilege of not being ruled (for good or for bad: that's another newsgroup)
by indigenous peoples. This is even more shocking in Mesoamerican and Andean
countries, in which the indigenous peoples are still a significant, and in
some cases majoritarian, proportion of the population. Now, (all?) African
and Asian countries are governed my members of their indigenous populations.
This difference, I hypothesize, has its ultimate causes in the epidemic
diseases. The big die-offs of 300-500 years ago had to have a devastating
effect on the collective psyche of the people in both sides of the
confrontation. "Your gods were more powerful than ours" and the doctrine of
manifest destiny are, I believe, the two faces of the same coin. Some of the
indigenous perceptions have been registered by early chroniclers in
Mesoamerica (cf Sahagun) and the Andes (cf Guaman Poma), but I have not seen
too many studies on that issue, with the noted exceptions of North America and
several Amazonian peoples, who have faced the problem relatively recently.

I am sure that more than one reader will take exception to several of the
points I have just written. Please forgive me if I limit my reactions to
issues in the thread that have not already been discussed.


As promised, some additional references that may be useful:

On population in the Americas: see previous post recommending Denevan (ed),
1992; Bray, Warwick (editor) 1994 (especially Newson's chapter).

On disease before and after contact, I still believe that Verano & Ubelaker
(editors) c1992 is a very important compendium. (a nice summary is also in
Brothwell's article in Bray's book.)

I have several references on domestication:

Rindos, David.
The origins of agriculture: an evolutionary perspective
Orlando : Academic Press, 1984.
(Seems to be the standard reference now. Very readable)

C. Wesley Cowan and Patty Jo Watson (editors)
The Origins of agriculture : an international perspective
Washington : Smithsonian Institution Press, c1992.
(Interesting comparisons. Nice brief book.)

Reed, Charles A. (editor)
Origins of agriculture
The Hague : Mouton ; Chicago, c1977.
(Lots of articles, including explanations on the relationship of crops and
animals: e.g. ungulates in the Americas were not near the areas where plants
existed; animal behavior; north-south axis in the Americas versus East-West in
Eurasia, etc.)

Sauer, Carl Ortwin
Agricultural origins and dispersals; the domestication of animals
and foodstuffs
2d ed. Cambridge, M.I.T. Press [1969]

(small book, also very easy reading).


Domingo Martinez Castilla