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Introduction to Public Health Diseases. Classes of Diseases. Vector borne illnesses Water borne illnesses Directly communicable illnesses Occupational and environmental illnesses Chronic illnesses. Impact of Diseases. Deaths in war
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Classes of Diseases • Vector borne illnesses • Water borne illnesses • Directly communicable illnesses • Occupational and environmental illnesses • Chronic illnesses
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
Disease agents • Living • parasites • spirochetes • amoebas • bacteria • virus • Environmental and Occupational • Asbestosis • Arsenic
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?
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
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)
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?
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?
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?
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
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?