314 CHAPTER 13 | Human Adaptation to a Changing Worldout the deeper, ultimate reasons that some individuals are
likelier than others to become sick. A strictly biological
approach also leaves out differences in the resources avail-
able to individuals, communities, and states to cope with
disease and illness. Prion diseases provide excellent illus-
trations of the impact of local and global factors on the
social distribution of disease.Prion Diseases
In 1997 physician-scientist Stanley Prusiner won the Nobel
Prize in medicine for his discovery of an entirely new dis-
ease agent called a prion—a protein lacking any genetic
material that behaves as an infectious particle. Prions
are a kind of protein that can cause the reorganization
and destruction of other proteins, which may result in
neurodegenerative disease as brain tissue and the nervous
system are destroyed.
This discovery provided a mechanism for un-
derstanding mad cow disease, a serious problem in
postindustrial societies. But knowing the biological
mechanism alone is not enough to truly grasp how this
disease spreads. The beef supply of several countries in
Europe and North America became tainted by prions
introduced through the cultural practice of grinding
up sheep carcasses and adding them to the commercial
feed of beef cattle. This practice began before prions
were discovered, but postindustrial farmers were aware
that these sheep had a condition known as scrapie; they
just did not know that this condition was infectious.
Through the wide distribution of tainted feed, prion
disease spread from sheep to cows and then to humans
who consumed tainted beef. Today countries without
confirmed mad cow disease ban the importation of beef
from neighboring countries with documented prion
disease. Such bans have a tremendous negative impact
on the local economies.
Mad cow disease is not new. This type of disease was
a major concern for the Fore (pronounced “foray”) people
of Papua New Guinea during the middle of the 20th cen-
tury. Kuru is the name given in the local language to the
prion disease that claimed the lives of great numbers of
women and children in Fore communities. To deal with
the devastation, the Fore welcomed assistance provided
by an international team of health workers led by a physi-
cian from the United States, Carleton Gajdusek. As with
mad cow disease, local and global cultural processes af-
fected both the transmission of kuru and the measures
taken to prevent its spread long before prion biology was
understood.
Kuru did not fit neatly into any known biomedical
categories. Because the disease seemed to be limited to
families of related individuals, cultural anthropologists
Shirley Lindenbaum from Australia and Robert GlasseAnother method for fighting infectious disease is the
development of vaccines. These stimulate the body to
mount its own immune response from the vaccine that
will protect the individual from the real infectious agent
if the individual is exposed at a later date. Vaccinations
have been responsible for major global reduction of dis-
ease, as in the case of smallpox. Historical records show
that people in India, China, Europe, and the colonizers
of North America practiced a form of vaccination for
this deadly disease through what were known as “pox
parties.”
Recently this tradition has been revived by parents who
choose to deliberately expose their children to chicken pox
rather than opt for the vaccine. Despite numerous medical re-
ports to the contrary, some parents believe that vaccinations
may lead to other health problems. Although the vaccine to
eradicate smallpox—a disease that killed 300 million people
in the 20th century alone—is clearly beneficial, it is harder
to convince parents of the need for vaccines for less fatal,
although still serious, childhood diseases.
The vaccine for chicken pox provides an interesting
case in point. Before this vaccination became standard
care in the United States, most American children experi-
enced chicken pox as a rite of childhood. Parents watched
their children become covered with ugly poxes that then
disappeared. This experience modeled a pattern of in-
tense sickness followed by full recovery, which, in and
of itself, can provide some comfort. Only very rarely is
chicken pox fatal.
Infectious disease and the human efforts to stop it
always occur in the context of the human-made envi-
ronment. Humans have been altering their external en-
vironments with increasing impact since the Neolithic
revolution, resulting in an increase in a variety of infec-
tious diseases. In this regard, evolutionary medicine shares
much with political ecology—a discipline closely related
to medical anthropology and described below.The Political Ecology
of Disease
An ecological perspective considers organisms in the con-
text of their environment. Because human environments
are shaped not only by local culture but by global political
and economic systems, these features must all be included
in a comprehensive examination of human disease. Simply
describing disease in terms of biological processes leavesprion An infectious protein lacking any genetic material but
capable of causing the reorganization and destruction of other
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