Articles, Blog

15. Tropical Medicine as a Discipline

December 22, 2019

Prof: Okay,
well let’s begin. And, as you know,
in our class one of the topics, or themes, that we’re
considering is intellectual history.
And lurking in the background,
of course, is the big question of medicine itself and what it
is. What is medical science?
What does it mean to have a
medical science? Well, this morning we’ll be
considering that. Is medical science purely the
technical application of neutral knowledge?
Or should we think of it as a
cultural institution, also, built by dominant social
groups in society, that in some way may reflect
their worldview, sometimes may embody their
prejudices, and may promote their interests?
And at least we should ask the
question, if we accept the biomedical paradigm of disease,
what are the implications of that acceptance?
What are the costs?
What are we giving up?
So, that’s the big issue.
And today what I’d like to do
is to look at a subset of the bigger problem,
and this is the medical specialization that’s known as
“tropical medicine.” It emerged in the 1890s,
in a period, that is, of–it gained rapidly
enormous prestige and influence, and is still a major subfield
in medicine. The discipline thus far has
undergone three periods in its history.
The first is the one that we’re
going to be concentrating on this morning,
and that’s the period from roughly the 1890s until more or
less the First World War. That marks the real heyday of
tropical medicine, the time when it was the
cutting edge of medical science, when it made a series of major
discoveries, and served the most obvious
political purposes. It was followed in its history
by a second period, that lasts more or less from
World War I until the 1970s, the next half-century of
tropical medicine. And during this period the
discipline loses a lot of its scientific momentum.
Tropical medicine came to be
confined essentially to parasitology,
and at this period, the dynamism in medical science
moved instead to microbiology and such offshoots as
immunology, and that boosted such major
developments as antibiotics and a series of effective vaccines,
and that attracted the lion’s share of research funds.
So, tropical medicine,
in the period from the First World War to the 1970s,
made relatively few major, major discoveries.
Then, after World War II,
and accelerating from the 1970s,
we see a third phase, ushered in by such things as
decolonization and a new attention to public health in
the Third World, and with it a new influx of
research funds through the World Health Organization and powerful
foundations like the Rockefeller and MacArthur Foundations.
Well, what I want to do this
morning is to look critically at tropical medicine.
And by that I don’t mean for or
against. What I want to do instead is to
look at why it arose as a discipline when it did.
What interests did it serve?
What were its implications?
And I’m going to argue that
tropical medicine, and particularly in this
formative early period before the First World War,
was clearly socially constructed.
This is a period that coincides
with the high tide of colonial expansion, the age of the
scramble for Africa. And tropical medicine gave
expression to an imperial view of the world,
and it marked the relationship, in medical terms,
between Western Europe, on the one hand,
and Asia and Africa on the other, and between the United
States and Latin America. As a discipline,
it served as a major instrument also in promoting European
expansion overseas, and American hegemony in the
Americas. In its applications,
and in the policies it promoted, tropical medicine was
not only value-neutral science; it was also an instrument of
power, and we need to bear that in mind.
Now, the emergence of tropical
medicine marked a transition, a transformation,
from something that had preceded it,
and that I hope won’t be confusing.
But from the middle of the
eighteenth century, more or less,
until the closing decade of the nineteenth century,
there had been an older tradition that can be summarized
under the label of “diseases of the
tropics.” And there were a couple of
classic statements of this older tradition.
One was a work,
an important work, by James Lind,
an eighteenth-century physician,
who wrote “An Essay on Diseases Incidental to Europeans
in Hot Climates,” and this was built on the
experience of Europeans in the West Indies.
And then there was another work
by James Johnson called “The Influence of Tropical
Climates on European Constitutions,”
built on the experience of Europeans in India.
What these works,
and other ones of their kind, meant in the expression
“diseases of the tropics”
was something particular. They meant that in the colonial
world– in, that is,
the area of hot climate, as it was expressed at the
time–Europeans were subject to special diseases as challenges,
that arose as a result of conditions peculiar to warm
climates, and to the resulting conditions
of temperature, humidity and local ecology.
Under those conditions,
the diseases that would afflict Europeans were not,
however, different in nature from those familiar at home.
The diseases of hot countries
were heightened in their virulence,
perhaps, and the constitutions of white people were now
subjected to new and unfamiliar stresses that made them
peculiarly vulnerable in these climates to disease.
But the issue was simply–in
the era, should we say, of diseases of the tropics–was
simply one of degree, rather than kind.
The diseases of the tropics
were simply intense variants of familiar disease processes.
And there was an educational
corollary to that, which was that physicians who
had studied general medicine, in European medical schools,
were fully equipped to treat the entire spectrum of human
diseases wherever they occurred. Diseases of the tropics weren’t
a special category. They were simply heightened
versions of familiar maladies. In other words,
the concept of diseases of the tropics presupposed a
universality of a single medical discipline that viewed the
diseases of the tropical world as posing problems of degree,
but not of a thoroughly different kind.
We should also say that this
idea of diseases of the tropics already did have embodied in it
some troubling and important questions that had to do with a
colonial or imperial and racial view of the world.
European bodies,
the concept presupposed, were different in some way from
those of Asians and Africans. They weren’t intended for the
conditions prevailing in the colonies, and so the question
was, were the tropics in fact inhabitable for Europeans?
You can see this in expressions
like “darkest Africa,” “teeming Asia”–
those imply dangerous places–and even more the
expression of “the white man’s grave.”
And, so, the question was
whether settling in the tropics was going to be possible.
Was it simply that Europeans
needed a period of seasoning– another term of the time–or
acclimatization, after which they’d be
stress-hardy and able to survive in these new settings?
Physicians who dealt with
diseases of the tropics thought of themselves as performing an
indispensable service, one that was useful to European
states, and especially to explorers,
travelers, settlers, colonial
administrators, and of course sailors and
soldiers. The service was to provide
assistance and advice during the time of acclimatization,
advice on exercise, diet, clothing and housing;
in short, everything that new arrivals would need to protect
themselves from the rigors of the new environment.
But the 1890s marked a
transition to something different–
from this view of diseases of the tropics,
to something that sounds subtly different,
but was profoundly so, and that is tropical diseases
and tropical medicine. Now, what was implied in this
transition, this transformation? It was a vision of the world in
which Asia and Africa, for Europeans,
or possibly Latin America, for U.S.
citizens, were conceived in a
really charged fashion as harboring disease that were
conceptually different from other diseases,
that could not be treated by physicians who had graduated
from European medical schools unless they had undergone
special postgraduate training. And the implication too was a
different form of hygiene. And there was a work that was a
foundational text for this new medical specialty,
one of the most influential medical works of the whole of
the nineteenth century, and one that had enormous
influence on the relations of the metropolitan powers to their
colonial dependencies. This work was by this man,
a British physician named Patrick Manson,
who came to be known as the father of tropical medicine.
The work that caused the stir
was called– it’s an enormous,
fat volume–entitled Tropical Diseases:
A Manual for the Diseases of Warm Climates.
And it was written in 1898,
which isn’t an accident. And it wasn’t also an accident
that the father of tropical medicine was British,
or that Britain became the world center of the new
discipline, Britain at the time being the
world’s leading imperial power. Now, what were the background
conditions that promoted the emergence of this whole new
medical sub-discipline? A first, as we said,
was Britain’s position as a great colonial power.
There were others,
as well, that lay behind this new medical specialism.
One was something we’ve already
dealt with, and that is the germ theory of disease and the
triumph of contagionism over anticontagionism.
The germ theory had a number of
possible implications. One was the idea,
as we’ve seen, of clinching the concept of
disease specificity. And tropical medicine was built
on the premise that some diseases lurking in Africa and
Asian now needed new classifications,
belonging in special categories, and that to
understand them– and here was another of its
implications– you needed physicians who were
trained at special institutions, and had a specialized
curriculum, and that they could be dealt with by specific
special remedies and measures of hygiene that were different from
those that had been successful in bringing about a mortality
revolution in Europe. As you’ll remember when we
examined the theories of Max van Pettenkofer,
the germ theory marked the end of an alternative approach to
medicine, one that had flourished at
mid-century, particularly in continental
Europe, but was intellectually
vanquished by the laboratory methods of bacteriology,
and later parasitology. This was the idea of social
medicine, associated with a radical German physician,
Rudolf Virchow. For social medicine,
medicine was a collective enterprise in which it was
important for physicians to treat not only individual
patients, but society as a whole,
dealing with issues of sanitary conditions,
poverty, nutrition, social justice.
Well, the germ theory of
disease was a setback for social medicine,
and I’m going to argue that tropical medicine went even a
step further in the turn from that direction.
It argued that in the tropical
world the chief problem– and we’re talking with the
period down to World War I– the chief problem was to
preserve the health of European settlers.
As a discipline,
until much later in its life, tropical medicine largely
ignored the general health of indigenous societies.
This also came to mean
something somewhat sinister, when the logic was applied to
the global north and south, and black/white relationships.
It seemed to suggest that the
bodies of Africans and teeming Asians were medically dangerous,
that they were the reservoirs for diseases that posed serious
new threats for Europeans. And there was an implication,
a possible strategy for hygiene,
and that was that perhaps the best way forward was for
Europeans and indigenous peoples to be segregated in their
housing arrangements, that Europeans should live in
the tropical world in special enclaves where the latest
prophylactic measures would be applied.
Whereas natives,
or indigenous peoples, could be left as they had been
found. Alternatively,
if you read some of the literature produced by works of
European writers such as Somerset Maugham,
you’d see that the Europeans were advised to take to the
hills during the dangerous summer months,
leaving dangerous natives behind.
But we shouldn’t forget that
tropical medicine, at the turn of the century,
was also where the scientific action and excitement in medical
science were taking place. Beyond the germ theory of
disease, tropical medicine embodied the various latest
developments, and above all the new science
of parasitology. And it attracted some of the
leading figures, indeed, in the development of
microbiology to enter this new discipline.
This was true,
for example, of Robert Koch,
who came, made a voyage, to Italy to study parasitology
in the form of malaria, and then set off for the
colonial world. Pasteur at this time had just
died, but his institute saw
affiliates or satellite institutes set up at Saigon,
at Tunis, Algiers, in the 1890s,
all preaching the new discipline of tropical medicine.
And Pasteur’s most famous and
able disciple, �mile Roux,
became a specialist in this new discipline.
To understand it,
we need to remember two major breakthroughs.
The first was by Patrick Manson
in 1883. At that time,
he discovered something that was radically new.
He was dealing with the disease
of elephantiasis, and he found that the filarial
worm that causes it is transmitted by mosquitoes;
the first example of a vector borne disease transmission.
This was epoch-making in that
respect. And it was also a movement from
bacteria or– though it wasn’t known at the
time– viruses, to more complex life
forms, the interaction of humans with
biologically more sophisticated protozoa or helminths or worms,
and with insect vectors. Diseases could now be seen to
be part of a much more complicated process,
and with complicated life forms.
Then there was,
following this, the establishment of the
mosquito theory of transmission for malaria,
which took place during the end of the decade of the 1890s,
with two figures, who were working independently
of each other, but in 1898 established that
malaria was a parasitical disease,
transmitted by certain species of mosquitoes.
So, malaria–which is a disease
that we’ll be dealing with after the spring break–
was of decisive importance in the establishment of tropical
medicine, and malaria was the disease
that was at its heart and its center.
The two people were in
Italy–and we’ll be coming back to this in a couple of weeks,
when we resume classes–in Italy there was Giovanni
Battista Grassi, who made a very elegant
demonstration, and a very convincing one,
that human malaria was transmitted by mosquitoes.
And he did so by experiments in
which he introduced just one variable in the exposure,
during the warm summer months, of large populations to biting
insects. He protected,
by screening, or later by chemical means,
select groups of people, while everyone around them was
falling ill of malaria. They lived in exactly the same
conditions as those around them, except for one variable;
that they weren’t subject to the bites of flying insects.
And thereby he established that
it was indeed insects, mosquitoes, and certain types
of mosquitoes; we’ll be returning to that.
Not all mosquitoes,
just anophelene mosquitoes, and certain species of them,
that transmitted the disease of malaria.
At the same time,
Ronald Ross, a British physician in India,
was working instead with malaria among the avian–
that is, birds–avian malaria, where he demonstrated that it
too was transmitted by the bites of mosquitoes.
And he argued,
by analogy, that human malaria was probably transmitted by
mosquitoes as well. Now, this was the age of a
ferocious imperial rivalry, and Ross was the first British
scientist to discover the pathogen of a major disease,
and he became a national icon, the British answer to Pasteur
or Koch. He won the Nobel Prize,
and along with Manson became one of two decisive figures in
the founding of the discipline of tropical medicine.
It was quite interesting that
there was an extraordinary collaboration between Manson and
Ross in India, where Ross wrote home what he
was finding under his microscope in India,
and sent that back to Manson, who worked with him in
suggesting new directions for his research,
and pushed him forward. So, in many ways the discovery
of the transmission of malaria belonged to Manson as well as
Ross. Well, in any case,
malaria became the template, the ideal type of tropical
diseases. And in Manson’s great work
malaria occupies the largest amount of space in the volume;
the reasons being that it was a perfectly vector-transmitted
disease, a perfect parasitic disease.
The plasmodium that causes it,
as we’ll see in a couple of weeks, lives in a closed cycle,
and never exists free in the environment.
Human beings don’t happen upon
it, and the plasmodium has an extremely complicated lifecycle
in both man and mosquito. And the involvement of the
mosquito also is scientifically complicated;
in other words, it was useful and important
that Grassi was a naturalist, was well as a physician.
Parasitology was scientifically
interesting, and intellectually so.
To study malariology,
one needed to be a physician, but also an entomologist,
a naturalist, and to have a knowledge of the
basic sciences. So, in 1898,
for a whole generation, parasitology replaced
bacteriology as the cutting edge of medical science,
and it became the foundation of this new discipline,
the rising discipline of tropical medicine.
Well, if that’s how it emerges,
what is the new discipline? Manson defined tropical
medicine in his great work. For him, it was a special
discipline, with diseases of an area defined by geography and
warm climate. Diseases there,
he said, were unlike the diseases of the temperate zone,
and they require therefore a special medical discipline to
deal with them, and they require physicians who
are specially trained in post-graduate institutes.
For that reason,
tropical medicine emerged outside of established medical
schools, because it presupposed that
physicians needed a special curriculum and training to deal
with diseases that were conceptually different.
For example,
in 1898, in association with Joseph Chamberlain,
the secretary of state for the colonies–
and you can see the role of the state in the promotion of this
new discipline, which was seen as important for
the promotion of imperial interests–
and with the collaboration of Patrick Manson–
there was founded the London School of Tropical Medicine,
with the specific intention of training colonial medical
officers in a new medical discipline;
or very closely associated was the Liverpool School of Tropical
Medicine. Another idea that Manson said
was essential to the new discipline was that tropical
diseases were caused not usually by bacteria but by more complex
biological agents, with complex
lifecycles–protozoa and helmets–
and that they were transmitted by insect vectors,
like mosquitoes or the tsetse fly.
Malaria had pride of place.
It was the ideal type to
illustrate this, and it’s the first disease that
Manson discusses in his work, and the disease he discusses at
greatest length. There were others of this type,
like trypanosomiasis, which was African sleeping
sickness, which was caused by a parasite
also that multiplies in the human bloodstream and causes
skin eruptions, anemia, chronic fever,
debilitation, lethargy and perhaps coma and
death. It was transmitted by the
tsetse fly. Or there was schistosomiasis,
caused by worms, with the snail as its
alternative host. Or leishmaniasis,
or yellow fever–a viral infection, it was later
discovered–transmitted by a certain species of mosquito.
Well, so far,
if you were reading Manson’s work,
you would’ve found the diseases I’ve just mentioned would be the
ones that you would’ve encountered,
and there was a kind of logical coherence to what they were.
Diseases of places with warm
climates, transmitted by mosquitoes, caused not by
bacteria but rather by more complex life forms.
But Manson then goes on.
And what we see then is
something of a grab bag of diseases, that don’t seem to
have much of a scientific connecting link.
He mentions certain infectious
bacterial diseases, some of them very familiar to
you already: bubonic plague, Asiatic cholera.
He adds leprosy.
He then moves on to certain
nutritional diseases: pellagra,
which is caused by a deficiency of niacin,
if your diet consists not of wheat,
but exclusively of corn; or beriberi,
or certain fungal diseases. And he even calls heatstroke a
tropical disease. Another background factor was
institutional. Should we call it the
institutionalization of this new medical discipline?
That is, it coincides with the
high point of European expansion.
And this wasn’t just a
coincidence. It was an important instrument
in the domination of Africa and India,
for instance, as important as gun powder,
enabling settlers to run mines and plantations,
traders to travel, administrators to govern,
missionaries to preach, and soldiers to perform their
duties. For this reason,
tropical medicine rapidly attracts governmental backing,
certainly in the British case, and institutional support and
assistance, from powerful economic
interests, with concerns in the tropical world.
So, these institutions–in
Britain we’ve already talked about the London School of
Tropical Medicine, the Liverpool School of
Tropical Medicine, the Royal Society of Tropical
Medicine and Hygiene. And it’s embedded in a new
major journal, The Journal of Tropical
Medicine and Hygiene, founded in 1895.
In France, we see the Pasteur
Institute; in the United States,
such institutions as Johns Hopkins,
the Rockefeller Institute–and in particular its International
Health Division– the American Academy of
Tropical Medicine, the American Society of
Tropical Medicine. And in the U.S.,
there were a couple of distinctive features.
One was the association of
tropical medicine with the military, and its leading
figures, Walter Reed and William Gorgas, were in fact Army
officers. And it was in the Western
hemisphere too that yellow fever replaced malaria as the
quintessential tropical disease. Some of the institutional links
can be seen in specific cases. An example that’s recently been
studied, somewhat intensively,
is the relationship of the Harvard Department of Tropical
Medicine to the colonial establishment of American power
in Liberia, and in particular the Firestone
rubber plantations. And one can see there the clear
role of tropical medicine in promoting,
if we like, the expansion of company interests to extract
resources from Liberia. This was an important
illustration of the uses that tropical medicine could be put
to. Well, what were some–if that’s
what tropical medicine was as a discipline–
what were some of its implications,
the implications of the worldview that it suggested?
One is that Africa,
Asia and Latin America had something in common.
This was an artificial
construction of European imagination.
They were seen as reservoirs of
diseases that threatened Europe; Europe protected by the
ramparts of civilization and medical science.
So, tropical medicine embodied,
down to a later period–certainly in this period
down to the First World War–a Eurocentric worldview.
It was initially not responsive
to specific locations, as the tropics were
artificially constructed as some single homogeneous place.
The natives of the tropics were
also conceptualized as somehow dangerous, harboring a vast
array of lethal and highly contagious diseases.
Another implication was that
tropical medicine was concerned, in the early decades of the new
century, primarily overwhelmingly,
with the help of Europeans– settlers, administrators,
missionaries and soldiers. There was little concern for
the health of the indigenous population.
Indeed, the medical problems of
the colonial world that received attention were those that
threatened Europeans, not the health problems of the
indigenous population. There was little attention to
the social and economic determinants of what we might
today call Third World problems of health,
such as poverty, labor conditions,
malnutrition. And there was a neglect of
major diseases that were often the major health problems of the
local population; say dysentery or gonorrhea,
pneumonia, tuberculosis. In recent years,
in fact, the blindness of the past has even resulted in new
international attention to a group of diseases,
termed neglected tropical diseases,
that cause large-scale suffering such as poverty,
low productivity, poor pregnancy outcomes,
but that for decades received little funding or attention from
policymakers. More ironically,
a major issue, not considered after World War
I, as I said, was the impact of
colonialism itself on the inhabitants of the tropical
world; that is, there was no attention
to the way in which colonialism itself contributed to
environmental degradation; or promoted labor mobility in
unsanitary conditions; the way in which it promoted
unplanned urbanization, low educational attainment and
poverty. In fact, this period,
the first period of tropical medicine,
from 1890 to just after the First World War,
was a time, one of the times, of the greatest epidemiological
disasters in the tropical world, with virgin soil epidemics,
like smallpox and measles, and the impact of what was
called constructive imperialism. Railroads, roads,
trade, the transportation revolution,
all enabled a pandemic of bubonic plague,
from the 1890s to 1920, and epidemic influenza,
in 1918 and ’19, to occur in the tropical world
as well. Colonial wars,
the involvement of the colonies in the two world wars,
had major disease impacts. So did the ecological impact of
railroads, factories, mines and plantations,
and the recruitment of migrant labor.
So, just as in the case that we
examined at greater length in your reading of North America,
disease played an important part in European expansion.
Another implication was public
health policy. In Europe and North America,
hygiene had given rise to a broad-gauge sanitarian movement;
one that reformed urban living conditions through what we might
call– and introducing a new jargon
into our course– horizontal programs of public
health; that is, improvements that
dealt with living conditions across a broad spectrum of
diseases. We’ve seen that in the sanitary
movement. In the tropics,
instead, metropolitan powers applied a different vision of
what was called vertical hygiene, or tropical hygiene.
Now, vertical campaigns of
public health targeted instead single diseases,
and they were designed to protect, above all,
Europeans against the most menacing epidemics.
That was tropical hygiene, then;
something different from what was practiced at the same time
in Europe, was one of the implications.
Another implication was a new
prestige and authority for physicians.
Ross and Koch,
for example, now became advisors to
metropolitan governments, as did Manson.
It meant also–another
implication was perhaps what we might call selective historical
amnesia. Many of the diseases identified
as tropical had only recently been present in Europe,
and they weren’t eradicated by temperature,
but by broad social and economic improvements.
Malaria itself had been a
European disease, as you know,
bubonic plague and cholera also.
And then tropical medicine was
clearly an instrument of cultural and ideological
hegemony. It was a justification and
rationale for colonialism. Europeans felt that they had
health and civilization to offer, and that medicine was a
means of winning acceptance of the colonial presence.
So, tropical medicine provided
a narrative of European progress,
rationality and civilization overcoming ignorance,
superstition, darkness and the witchcraft of
natives. Patrick Manson was very
explicit in his vision of the relationship of medicine and
empire. In a simple sentence he
declared, “I believe in the colonization of the world by the
white race.” Well, that was the early period
of tropical medicine, between 1890,
more or less, and just at a period after the
First World War. Later we see a transformation
in the discipline. And I don’t want to argue that
it’s the same today as it was at the eve of the First World War.
Radical changes in tropical
medicine came through a number of influences.
One was the Second World War
itself, which was in part–and although
there were deep contradictions involved in it–
it was in part, at least, a war against
racialism. The discipline was affected by
decolonization, also by the rise of American
hegemony after World War II, with new priorities.
It was influenced by
globalization as an explicit idea,
and its implications that we all live in a single disease
environment, and that what happens in
distant parts of the world are also vitally important for the
entire world population. And then there was–what was
very important also was a transformation in funding.
Because of those factors,
around and during the 1970s, The World Health Organization
introduced a major new emphasis on tropical diseases,
and with it, in 1975, a major new research
project. The same happened with the
Rockefeller Foundation in the 1970s, and then the MacArthur
Foundation thereafterwards. And this meant a new dynamism
scientifically for the discipline of tropical medicine,
and also with that a major attention,
reversing an earlier trend, with an emphasis on global
health programs that would be applicable everywhere,
and that would include major attention to the health of the
population of indigenous peoples in areas that had been neglected
by an earlier phase of tropical medicine.
And, so, the entire discipline,
if we like, was transformed after World War
II, and became something that no
longer embodied a colonial position,
and no longer embodied the idea that it was the bodies of
Europeans that deserved privileged protection,
rather than the health of indigenous peoples in other
parts of the world. So, tropical medicine was a
very important instrument of colonial power in the period
down to the First World War, and it was slowly transformed
in the inter-war period, and radically so after World
War II. I hope you’ll bear that in mind
as you think about the issue of what are the implications of
medical science; and what are its implications
for the kinds of society and the world that we live in?

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