The following
are responses and summaries of various readings related to Human Health,
Disease, and the Environment.
Under the Weather:
Executive Summary
Changes in climate can affect the movement pattern of
infectious diseases due to the fact that the microorganisms and their carriers
are equally prey to changes in temperature, moisture, and other environmental
changes, though other diseases such as HIV or Hepatitis do not have the same
causal relationship with the environment because they are transmitted through
direct human interaction. In 2001 the
National Research Council was asked to study the issue of the environment, its
change, and the possible effect on human health and disease. Specifically they reviewed: 1. possible
connections between the variations of time and space with respect to the
climate and the transmission of disease 2. Studying the possibility of creating
warning and surveillance systems for climate affected diseases 3. Investigating
possible future studies on the relationship of disease, climate, and human
health. Multiple disciplines, whom
usually do not work together or in similar fashion, were required for the
project due to the multidisciplinary nature of the issue. Temperature, precipitation, and humidity
directly and indirectly change the life of many infectious diseases and their
vectors, though they are also affected by the sanitation and health services
provided within a region, the density of human or vector population, changes in
ecology, and organism travel habits. Many
studies have been conducted on the effect of climate change on disease however
they have not been able to account for the many variables that lie under the
function of diseases and are not reliable for predicting future change. The impact of climate change on disease has
yet to be well sorted out, though many believe that global warming could have
an adverse impact, however human adaptations and health services could
potentially prevent or reduce such impacts.
New diseases may emerge or old diseases reemerge in newly evolved forms
due to ecosystem changes. Studies of the
relationship are dependent on local, small scale which make it difficult to
enlarge the results to a larger scale relationship. Long term climate change could have a vastly
different effect than short term climate change such as ENSO. Advances in technology will allow for the
analysis and more detailed studies.
Historically the strategy has been to survey and respond to disease
threats, but in the future hope is for a predict and prevent strategy. Climate forecasts and observations could be
used in identifying high risk areas and preventing the or reducing their
occurrence. A general understanding of
the relationship may allow for some form of early warning system at a low cost,
but some may require a more costly prediction system, depending on the
particular disease and region. Systems
will only be beneficial if the operating agency has the sufficient resources to
act upon their results. Climate
forecasts must also be combined with meteorological, ecological, and
epidemiological systems to work properly as an advanced warning system. Public health officials and government
agencies must work in conjunction with one another for the systems to have
their desired effect. The research into
these relationships has only just begun and has a long road to traverse before
it can become effective. The data set
involving disease, climate, and geography need be greatly increased for
prediction models to even be a possibility.
The interdisciplinary collaboration in universities and private
institutions need be greatly increased.
New disease will always have the upper hand in the battle, however the
goal should be to reduce people vulnerability to disease.
Intro
Hippocrates was one of the first major scientists to link the
change in weather and climate with the transmission of disease and human
illness. The term under the weather is
taken from the idea of unidentifiable cause of sickness or a temporary
illness. The advent of microbiological
study greatly aided the fight against infectious disease with many countries improving
the health of their populace through using pesticides, improving sanitation and
water services, and public health services since the 1960s. Though recently infectious diseases have
begun a comeback due to their fast evolution against pesticides and drugs, the
emergence of new diseases, the fast travel of adaptations due to modern human
behavior, and weakened resources for public health programs. The relationships between climate and disease
are difficult to establish due to the fact that the health services field has
not historically used predictive models or forecasting tools, the transmission
of disease can be related to non-climate factors such as ecology, biology, and
societal change, and the data that has been collected is few and far between.
Many studies have linked the change in climate, mostly global warming trends,
with an increase in disease though at the moment there is little actual
evidence for this conclusion and few of these studies consider human travel,
reduced public health efforts, and the great increase in drug and pesticide
resistant diseases. With an increase in the knowledge of the relationship
between disease and climate it is hoped that a strategy of prediction and
prevention can become a possibility in the future with a better understanding
of the climate and ecology that is favorable to disease transmission.
The Past as Prologue
Hippocrates was one of the first to directly link disease to
the weather rather than to the divine, though much lore had been passed down
attributing illnesses to weather and seasonal changes before him. Astrology was the science of choice for the
explanation of epidemics throughout much of the first millennium. Though with the appearance of the black death
in the twelfth century this began to fall apart as a particularly effective
methodology. In the 1400s Italian
officials began collecting data on the deaths of its citizens in order monitor
the disease and potentially predict dangerous times and places of infection. This time also saw an increase in the need of
diagnostic medicine because people wished to not be marked as having the plague
and therefore not be segregated from family, friends, and community. Later in the 1600s an effort was made to
combine the data of meteorology with medicine in relation to illness. The 1700s saw the birth of great social
reform in Europe with improved sanitation systems, water treatment services,
and the attribution of particularly dangerous locations with disease and deaths. Meteorology in the U.S. was developed around
the mid 19th century in order to link disease and weather, though
they would take use of the telegraph before the civil war in the belief that
they could use it in the warning of future weather catastrophe and prevention
of loss and death. After World War I
meteorologists began creating more weather stations, better instruments, better
training methods, and the standardization of methods for internationalization
of study. With the advent of the first
computers they were able to begin making predictive model systems, though it
was obvious from the beginning that the slightest differences in accuracy would
create great differences in the end result of the calculated predictions. Edward Lorenz described the issue with the
analogy of the butterfly flapping its wings in Brazil potentially creating a
tornado all the way in Texas. He implied
that weather is a chaotic system, but its prediction, while difficult, is not
impossible. Epidemiology emerged in the
mid 1800s: some studying the issue of creating safe airs, waters, and
locations, while others tried to link social issues such as poverty, hunger,
criminality, and occupation with disease and illness. In the beginning the focus was either on the
study of individual diseases in a lab setting or on associating disease with a
particular region, time, season, or population.
1882 saw Robert Koch further define germ theory creating the first
revolution in epidemiological study. The
second revolution was after World War II when the focus shifted to the
environment, along with human behavior and habit. Modern studies are more focused on the grand
scheme, attempting to factor in all the potential variables. More recently historians and meteorologists
have begun collaborating in an attempt to collect data on past climate events
while the epidemiology field has become somewhat more independent from medicine
and public health fields and has built the tools in order to address complex
health issues.
Global Climate Change –
Federal Research
Over the past century the global average temperature has
increased by about 0.9 degrees Celsius.
Prediction models estimate that throughout the next one hundred years
the average temperature will increase anywhere from 2 to 7 degrees Celsius
globally, which could result in more extreme weather more often, longer and
more often hot seasons, changes in precipitation patterns, and longer harsher
droughts. Human health issues are not
directly related to the change in climate, however they are made more intense
by these fluctuations. The effect that
climate change could have on air and water supply and quality would be the
greatest of all the potential pitfalls. A
warmer environment has many possible ill effects from past experience
including, excess hospitalizations and deaths due to heat, increased allergens
and asthmatic issues, increased occurrence and influence of disease from
bacteria and viruses, more extreme weather, and additional indirect effects
from these extreme weather events. More
people seem to die from extreme heat fluctuations than from extreme cold
fluctuations. Proper health services,
sanitation, building code, and other societal factors can keep extreme weather
events from being so very influential.
Agriculture can be greatly affected by climate change, though with
proper technology and monitoring this can be limited. The ever increasing average age will factor
in to a greater possibility of more of the population being susceptible to the
detrimental effects of climate change.
More people continue to move into urban settings and therefore will
suffer more from any severe climate change as urban centers are generally
hotter. The sick, old, and poor will be
most harshly affected by any possible change.
Disease could be come more prevalent and more dangerous with climate
change, however more research is needed in the field to relate the two.
Black Death
The Black Death was also known in past times as the Great
Pestilence or the Great Plague. The name
Black Death is derived from the color of its victims skins in the later stages
and its causing of gangrene. It is
believed that the disease was spread by fleas, with the assistance of
rats. Poor sanitation conditions and
high population density in cities were very influential in the great scale of
its effect. The particular disease which
was at the bottom of the black plague has never been sufficiently determined
but the common belief has been that of the Yersinia
pestis (bubonic plague). It is
believed that the plague began in the far east and spread to Europe by the
twelfth century. The total number of
casualties has been estimated at around 75 million people including 30% to 60%
of the total population of Europe. The
plague ruled Europe from the 1300s through the 1800s. The plague caused a great many social reforms
to be instituted throughout Europe. Many
people attributed the Black Death to astronomical causes, while others
attributed it to the actions of the Jewish community. Thousands were killed in acts of
vengeance. The plague itself had very
detrimental effects on the Catholic Church, as many of the people who cared for
the plagues victims were monks or other church officials, and the church’s
populace questioned why there was nothing the papacy could do to stop the
spread. The Black Death was a pandemic
on a scale which has not yet been repeated, however many predict that it is
only a matter of time before it happens again.
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