Environmental Engineering Reference
In-Depth Information
estimates come closer to reality than the present CDC reporting would indicate,
particularly to the nonprofessional. The estimates would also serve as a truer
basis for justifying regulatory and industry program expenditures for waterborne
illness prevention, including research and quality control.
Historical Waterborne Disease Background
Prior to the mid-1800s, understanding the connection between routes of disease
transmission and the causes of illness was greatly hampered by the ignorance of
mankind concerning the existence and role of pathogenic agents. Two centuries
separated the seminal discoveries of the basic biological cell, including the exis-
tence of microbial beings, and the demonstration that certain microorganisms
were at the root of disease formation and decay. Prior to the formative years
of the field of microbiology, civilization regarded the onset of infections as the
curse of some undefined phenomenon of fouled air (miasma), and treatments of
the sick were largely relegated to the practice of quarantine or administering of
harsh chemical potions. Pollution of water sources was rampant. Some chose to
intuitively avoid contact with such waters, not because of any knowledge of the
presence of disease-producing agents, but because of the intolerable offensive
odors. Indeed, such philosophy was espounded by Dr. John Sutherland, a Scot-
tish physician, when asked in 1854 to comment on the origins of the London
Asiatic cholera epidemic of 1853 to 1854: “There is no sufficient proof that water
in this state [of impurity] acts specifically in generating cholera” [but] “use of
water containing organic matter in a state of decomposition is one predisposing
cause of cholera. 38
Diseases such as cholera, typhoid, typhus, and dysentery were common in the
United States, Europe, and other parts of the world prior to the 20th century.
Three classical waterborne disease outbreaks are summarized next.
Asiatic cholera produced two epidemics in London in the years 1849 and 1853,
both of which were investigated by John Snow, a physician in the twilight of his
life, who came to believe that the feces of cholera patients were the source of
the disease. 28 It was the Italian physician, Filippo Pacini of Florence, 39 however,
who actually observed the cholera vibrio in the intestinal tissue specimens of
a deceased victim with the aid of a microscope and deduced the relationship
between the bacteria and the disease. Snow noted that the Broad Street well in the
SoHo district of London — specifically, St. James Parish, Westminster — served
an area where 616 people had died during a 15-week period, and the death rate
for St. James Parish was 220 per 10,000, compared to 9 and 33 per 10,000 in
adjoining subdistricts.
Snow found that a brewery on Broad Street employing 70 workmen had no
deaths. The brewery had its own well, and all the workers had a daily allotment
of malt liquor. It can be reasonably assumed that these workers did not drink
any water. In contrast, at a factory at 38 Broad Street, where only water from
the Broad Street well was available, 18 of 200 workers died (900 per 10,000).
But in a nearby workhouse, which had its own water supply in addition to the
city supply, there were only 5 deaths among 535 inmates.
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