The Return of Infectious Disease

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The Return of Infectious Disease
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Goal of public health programs world wide has
been eradication on a large, military-style
scale. Microbes would be eliminated. World would
be pushed through a health transition.
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Based on two assumptions 1. Microbes are
biologically stationary. 2. Diseases could be
geographically sequestered. Wrong on both counts.
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Air travel to developing world has exploded. 500
million passenger trips per year. Movement of
goods also important, eg., bilge water from Asia
brought dengue fever to South America. Now spread
to Central America. Vector is a mosquito.
http//www.bc.edu/schools/cas/biology/meta-element
s/gif/dengue.gif
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http//survivalskills.blogs.com/outdoor_survival_s
kills/dengdis2-thumb.gif
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Genetic mutation allows plants and animals,
including microbes, to mutate to adapt to
environmental conditions. Allows them to
survive. Widespread misuse of antibiotics has
aided this, both in the developing and developed
world (eg., when antibiotics are given for
viruses or not taken completely)
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Also widespread use of antibiotics in livestock.
(prophylactically) Good Leads to larger (5)
animals. Bad Greater opportunities for bacteria
to mutate. Bacteria have been shown to share
genes. Hardier strains share drug resistant genes.
http//i.timeinc.net/time/covers/1101020121/images
/antibiotics.jpg
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There are pockets of drug-resistant tuberculosis
(TB) on all five continents. Called multi-drug
resistant, or MDR TB.
http//www.disasterrelief.org/Disasters/990319tube
rculosis/Images/MDRMap.jpg
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We have upset the natural order. Eg Hantavirus
from mouse droppings - fatal in 50 of human
cases. Human-kind reduced the number of predators
(owls, wolves, foxes, etc.) and then one good
year for mice and their population
exploded. Hantavirus also exploded.
http//www.scchealth.org/docs/eid/images/hantaviru
s.jpg
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Few new drugs are being developed. Three
reasons Its not worth the companies investing
the money. Researchers have run out of
ideas. Pace of genetic change is very rapid.
Cant keep up.
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World Bank, the IMF and other agencies now
believe that health infrastructure must be
improved before development and economic growth
can take place.
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Urbanization puts more people in close
contact. Urban residents visit rural areas and
bring back disease. New urban places lack
infrastructure to control infectious disease
(sewage, water, hospitals, etc.)
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Urbanization leads to sex trade
concentration. Intravenous drug use also
increases.
http//www.narconon.org/druginfo/outsyringe.jpg
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• Pneumonic plague Sarat, India 1994
• Pulmonary infection that occurs upon inhalation
  of plague bacteria.
• Without early treatment in less than 24 hours,
  pneumonic plague almost universally leads to
  respiratory failure, shock, and rapid death.
• Pneumonic plague can be transmitted person to
  person through respiratory droplets with direct
  close contact.
• The total official number of deaths reported was
  234 nationwide. Unofficial estimates indicate
  several hundred deaths.
• Lessons

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Human mobility 500 000 people fled to every
corner of the country. Transparency India
reluctant to disclose information. Spread
rumours, etc. Tensions between states stock
markets tumbled, India lost 2B in a day.
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Outbreaks of disease have caused state
failure. Anarchy can occur when social and
political institutions fail.
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What can be done? 1. Boost research. (More money
is flowing.) 2. Enhance surveillance. 3. Promote
basic public health. 4. Ration and control use of
drugs. 5. Infection control at hospitals.
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6. Focus on microbes that are currently not
directly dangerous to humans but might be. The
key Money.
http//www.free-graphics.com/backgrounds/misc/mone
y.jpg