Lecture 5 Reading.doc

14 views10 pages
Published on 5 Jul 2012
School
UTSC
Department
Geography
Course
GGRB28H3
Lecture 5 Reading
Cohen-patterns in infectious disease
-In 1931, Henry Sigerist wrote, ‘Most of the infectious diseases … have now yielded
up their secrets…. Many illnesses … had been completely exterminated; others had
[been brought] largely under control….’ Between 1940 and 1960, the development
and successes of antibiotics and immunizations added to this optimism, and in 1969,
Surgeon General William H. Stewart told the United States Congress that it was time
to ‘close the book on infectious diseases’
-increasing emphasis was directed at the non-infectious diseases such as cancer and
heart disease. Often, research on infectious disease or activities on their prevention
and control were de-emphasized and resources were reduced or eliminated
- pharmaceutical companies, believing that there were already enough antibiotics,
began reducing the development of new drugs or redirecting it away from antibiotics
-optimism was soon shaken by a series of outbreaks and epidemics of new, re-
emerging and antimicrobial resistant infections. Legionnaire’s disease, Ebola virus,
HIV, ‘flesh-eating’ bacteria and ‘mad cow disease’ (bovine spongiform
encephalopathy)
-diseases, occurring both in the developing and developed worlds, indicated that
much was still unknown about infectious diseases. At the beginning of the twenty first
century, infectious diseases were once again capturing the attention of public health
workers, academics, government and the general public
Infectious diseases in the twentieth century
-beginning of twentieth century infectious disease was the leading cause of the death
-USA main 3 were TB, pneumonia and diarrhoeal disease
-from 1700 to 1900 all the infectious disease transmission were down and life
expectancies were going up because they had goo nutrients and the increase in
further bringing down the mortality rate was because of the antimicrobial agents
-smallpox was eradicated in 1977
-By the end of the twentieth century, in most of the developed world, mortality from
infectious diseases had been replaced by mortality from chronic illnesses such as
heart disease, cancer and stroke
-The developing world didn't have the same success with infectious diseases: they
remained the major cause of morbidity and mortality
-The societal and technological advances that had influenced infectious diseases in
the developed world had less of an effect in the developing world. At the end of the
twentieth century there were worrying trends in both the developed and the
developing worlds. New infectious diseases and microorganisms were being
recognized: Legionnaire’s disease, toxic shock syndrome, Lyme disease, HIV, Nipah
virus, hantavirus, Escherichia coli O157:H7, ‘flesh-eating’ bacteria, and many others.
Infectious diseases were also being recognized as the cause of chronic illnesses;
Helicobacter pylori, for instance, is now known to be the cause of peptic ulcers. New
infectious agents, such as Ebola or Marburg virus, had the potential for rapid
international spread. Diseases such as cholera, tuberculosis, dengue fever, yellow
fever and malaria, which had once been controlled in many parts of the world, were
re-emerging. Resistance to antimicrobial agents was becoming a serious global
problem
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in
Factors influencing emergence
-The IOM report identified six factors as influencing emergence of infectious disease
-Many of these factors increase the susceptibility of populations to infectious
diseases or increase the exposure to or transmission of infectious agents. Emergence
is often the consequence of societal and technological change and is frequently
unexpected and unpredictable. In most instances the emergence of a specific agent
results from a complex interaction of several factors that can vary even by
geographic area.
-vancomycin-resistant enterococci (VRE) emerged in hospitals in the United States
because of antibiotic use combined with inadequate infection control practices and
simultaneous increases in the number of susceptible persons in intensive-care units.
-some factors that have resulted in a decline in one disease can contribute to an
increase in another. The development of refrigeration, for instance, made food safer
by inhibiting the growth of most food-borne pathogens, but it provided an advantage
to organisms such as Listeria or Yersinia that can grow in
the cold.
Changes in demographics and behaviour
-Demographic changes fall into several broad areas: changes in population, such as
the increasing prevalence of persons with susceptibility to infection; societal
changes, such as increases in two income or single-parent families (which in turn lead
to a greater use of day care for children and subsequently to an increase in disease
transmission); and movements of infected or high-risk populations by immigration.
Changes in behaviour include various factors from increases in recognized risky
behaviours, such as unsafe sex or the use of alcohol or drugs, to risks that are often
unrecognized, such as recreational activities, exposures to new geographic areas and
patterns of use of antimicrobial agents
-Increase in susceptible population is also another reason
-Ageing of the population, increases in underlying diseases and technological
advances in health care have all contributed-with an ageing population, there are
more persons that are susceptible to certain diseases and a larger group that might
sustain transmission. Similar increases are occurring in the number of persons with
underlying diseases or conditions that contribute to susceptibility. Malnutrition
contributes to susceptibility to infectious diseases in many parts of the developing
world
-increase in ICU patients have contributed to emergence of antimicrobial resistance
and greater incidence of fungal disease
-Smoking has been associated with pneumococcal disease. Intravenous drug use has
been associated with sexually transmitted diseases, including HIV. Changing eating
habits are exposing people to new foods with unfamiliar risks, to foods eaten without
further preparation or to foods prepared outside the home.
-One of the strongest influences on the emergence of resistance has been the
unnecessary use of antimicrobial agents. In many parts of the world, antibiotics are
available over the counter. Even in countries in which use is more controlled, their
use is often unnecessary
Changes in technology and industry
-Air conditioning was associated with legionnaire's disease, super absorbent tampons
to toxic shock syndrome and the fast food hamburger to E.coli
-Food industry had to change how they preserve, produce or processed food
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in
Environmental change and land use
-Changes in environment and in land use are global activities that include both
natural and man-made changes. In the developing world, these include the
encroachment on the tropical rain forest, which poses a risk for the emergence of new
hemorrhagic fever viruses. They also include the impact of growing megapolises often
with inadequate hygiene and sanitation.
-The spread of cholera in Latin America during the 1990s was facilitated by such
conditions. In the developed world, agricultural practices have contributed to blooms
of pfiesteria and toxic algae. Conservation efforts, such as preserving deer
populations, have led to the spread of Lyme disease. Climate change, whether natural
or man-made, is also contributing to the emergence of infectious diseases.
International travel and commerce
-international travel most impressive change in the 20th century
-Travel reduced from months to hours
-However this can help spread disease alot quicker and has the ability to jump to new
environments
Microbial adaption and change
-microorganisms are starting to become more resistant to antimicrobial agents
-E. Coli O157:H7 was the genetic results of Shigella and Salmonella
Breakdown of public health measures
-TB made a comeback after acquiring its antimicrobial resistance
-Change leads to emergence of new diseases
-Will identify infectious agents as contributors to many chronic diseases
-The infection itself might be symptomatic or asymptomatic
-Food borne illness big issue
-emergence of non-typhoid salmonellosis, campylobacteriosis, listeriosis, and
infections involving E. coli O157:H7, Cyclospora, calicivirus and Vibrio vulnificus.
-One plan developed by the Centers for Disease Control and Prevention identifies four
major strategies: (1) enhancing surveillance and response, (2) encouraging applied
research, (3) strengthening the infrastructure for public health and providing training
opportunities, and (4) developing, implementing and evaluating strategies for
prevention and control
-optimism that we were going beat the infectious diseases
-increases in infectious diseases only for usa is the chart
-Demographics, since we see people live longer makes us more susceptible
population
-Behaviour, puts us in closer proximity to diseases
-Technology, can be spread around the world because of air travel
-created antibiotics
-technology might be bad, some bacteria do well in cool air
-environmental change, malaria affected usa in the slum like areas and specifically
black people
-international travel and commerce. can get foods from all over the world
-microbial adaptation and change: bacteria mutating and developing
McMichael
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in

Document Summary

In 1931, henry sigerist wrote, most of the infectious diseases have now yielded up their secrets . Many illnesses had been completely exterminated; others had. [been brought] largely under control . " between 1940 and 1960, the development and successes of antibiotics and immunizations added to this optimism, and in 1969, Surgeon general william h. stewart told the united states congress that it was time to close the book on infectious diseases". Increasing emphasis was directed at the non-infectious diseases such as cancer and heart disease. Often, research on infectious disease or activities on their prevention and control were de-emphasized and resources were reduced or eliminated. Pharmaceutical companies, believing that there were already enough antibiotics, began reducing the development of new drugs or redirecting it away from antibiotics. Optimism was soon shaken by a series of outbreaks and epidemics of new, re- emerging and antimicrobial resistant infections. Hiv, flesh-eating" bacteria and mad cow disease" (bovine spongiform encephalopathy)

Get OneClass Grade+

Unlimited access to all notes and study guides.

YearlyMost Popular
75% OFF
$9.98/m
Monthly
$39.98/m
Single doc
$39.98

or

You will be charged $119.76 upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.