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WaterborneDiseases_2010_to_post

WaterborneDiseases_2010_to_post - SurvivalofPathogens ....

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Survival of Pathogens Risk is not as high as it may seem. Most pathogens require rather specific condi9ons, e.g. target 9ssue, environmental condi9ons, specific substrates, etc. Pathogens are usually not well‐adapted to the aqua9c environment. Self‐purifying condi9ons of natural aqua9c environment Dilu9on and sedimenta9on Exposure to light Starva9on Preda9on by other organisms Lack of growth Possible loss of pathogenicity Dose and exposure depends on pathogen, general health and immune status of the host. Commonality of waterborne diseases ‐ poor sanita9on ‐ oral‐fecal route of transmission ‐ gastrointes9nal illness
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Water treatment and waterborne diseases Snow on Cholera 1855, physician John Snow did the first epidemiological study showing that cholera is spread by contaminated drinking water. Drinking water in London was supplied by private companies that took water from different sources. S&V Company and Lambeth Company supplied water in compe9ng and overlapping district. Snow took a detailed survey of each house with a cholera death and what water company they used. First 7 weeks of epidemic, 315 deaths per 10,000 houses with water from S&V; and 37 deaths per 10,000 houses with water from Lambeth. Rest of London, 57 deaths/10K houses. S&V took water from the Thames right in town, while Lambeth took water from the river several miles above town. Snow suspected this knowing that untreated sewage was dumped directly into the Thames. At that 9me, there was no knowledge of the bacterial cause of the disease.
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Typical water treatment process This is the same process that is found in the New Brunswick water treatment facility on campus.
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WATERBORNE DISEASES CHOLERA Vibrio cholerae enterotoxin massive fluid loss – up to 20 L/day dehydra9on, death in 2‐3 days, 60% mortality Peru, 1991 – contaminated fish, fruits, veggies; >1M cases; > 10K deaths TYPHOID Salmonella typhi ‐ specific to humans, sole source of infec9on contaminated food dose dependent: 10 3 , 10 7 , 10 9 /ml = 0/20, 16/32. 40/42 clinical disease incuba9on 1‐3 wks, fever, headache, anorexia, enlarged spleen, cough, cons9pa9on can carried in gall bladder Story of Typhoid Mary: early 1900s, employed as a cook in different households and ins9tu9ons; iden9fied as the source of contamina9on and thought to be a carrier in her gall bladder; imprisoned for 3 yrs & released with promise not to handle food or cook, and report to the health dept. regularly; disappeared, changed her name, con9nued to cook in
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