Introduction to Public Health Diseases
Classes of Diseases
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Vector borne illnesses
Water borne illnesses
Directly communicable illnesses
Occupational and environmental illnesses
Chronic illnesses
Impact of Diseases
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Deaths in war
 World War I was the first war where wounds killed
more people than illness
Life expectancy
 Early deaths count more
 That is why it is hard to raise it once you get to 75
 Communicable diseases keep the life expectancy low
 Diarrheal diseases are the biggest killer of children
worldwide
Disease agents
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Living
 parasites
 spirochetes
 amoebas
 bacteria
 virus
Environmental and Occupational
 Asbestosis
 Arsenic
Vector Borne Illness
Mosquito borne - Examples
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malaria
 spirochetes
yellow fever
 virus
West Nile, St. Louis Encephalitis, etc.
 virus
Dengue fever - bone break fever
 virus
Why is mosquito borne illness consistent with a miasma?
Ticks, Fleas, Bedbugs - Examples
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Lyme
 spirochetes
 deer ticks
Typhus
 Bacteria
 fleas - rats and other carriers
Bubonic plague
 bacteria
 fleas, then direct human
Ehrlichiosis
 Bacteria
 Ticks
Other agents
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Schistosomiasis (Aka: Bilharziasis)
 Flukes
 Intermediate host - snail
 Potentiated by the Aswan Dam
Trypanosomiasis
 African: Sleeping sickness (Tsetse flies
 American: Chagas Disease (Reduviid bugs)
Incidental Transmission
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Polio
 virus
 fecal-oral transmission
Flies
 get the virus on their feet when sitting on shit
 carry the virus to food
How do you control flies?
Legal issues?
Transmission and Control of Vector Borne
Illnesses
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Usual model is that the mosquito carries the illness from
an animal reservoir
 can you control the animal?
 can you eradicate the animal?
Vector
 Can you control the vector?
Human behavior
 Can you avoid contact with the vector?
Treatment
 Can you treat the illness?
Malaria Control - - #1 debilitating
infectious disease
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The reservoir is human
 Why is this a special problem?
Treatment
 spirochete develops resistance
 requires long term treatment
Mosquito control
 drain the swamps
 spray
Avoidance
 repellant
 bed nets
Legal Issues?
Water Borne Illness
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Cholera
 bacterium Vibrio cholerae
 endotoxin - shuts down water reabsorption
Typhoid
 Salmonella Typhi
 human reservoir
Both fecal-oral
 environmental and direct human spread
Controlling Water Borne Illness
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Waste water management
 Treatment
 Disposal to avoid cross contamination
 Oysters, any one?
Drinking water treatment
 Chlorination
 Making sure you only get treated water
Vaccinations
 Limited value
Legal issues?