Why is mosquito borne illness consistent with a miasma

1
Introduction to Public Health Diseases
2
Classes of Diseases

• Vector borne illnesses
• Water borne illnesses
• Directly communicable illnesses
• Occupational and environmental illnesses
• Chronic illnesses

3
Impact of Diseases

• 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

4
Disease agents

• Living
• parasites
• spirochetes
• amoebas
• bacteria
• virus
• Environmental and Occupational
• Asbestosis
• Arsenic

5
Vector Borne Illness
6
Mosquito borne - Examples

• 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?

7
Ticks, Fleas, Bedbugs - Examples

• Lyme
• spirochetes
• deer ticks
• Typhus
• Bacteria
• fleas - rats and other carriers
• Bubonic plague
• bacteria
• fleas, then direct human
• Ehrlichiosis
• Bacteria
• Ticks

8
Other agents

• Schistosomiasis (Aka Bilharziasis)
• Flukes
• Intermediate host - snail
• Potentiated by the Aswan Dam
• Trypanosomiasis
• African Sleeping sickness (Tsetse flies
• American Chagas Disease (Reduviid bugs)

9
Incidental Transmission

• 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?

10
Transmission and Control of Vector Borne Illnesses

• 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?

11
Malaria Control - - 1 debilitating infectious
disease

• 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?

12
Water Borne Illness

• Cholera
• bacterium Vibrio cholerae
• endotoxin - shuts down water reabsorption
• Typhoid
• Salmonella Typhi
• human reservoir
• Both fecal-oral
• environmental and direct human spread

13
Controlling Water Borne Illness

• 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?