THE MAIN PURPOSE OF A LABOR UNION / TUTORIALOUTLET DOT COM THE MAIN PURPOSE OF A LABOR UNION / TUTORIALOUTLET | Page 78

John snow, the risk of cholera
was related to the drinking of water supplied by a particular company.
John snow located the
homes of each individual who died from cholera in London during
1848-49 and 1853-54, and
noted an apparent association between the source of drinking water
and the deaths. He compared
cholera deaths in districts with different water supplies and showed
that both the number of
deaths and threat of deaths were higher among people supplied water
by a specific company.
Snow constructed a theory about the communication of infectious
diseases and suggested that
cholera was spread by contaminated water {Bauch et al., 2013}.
Epidemiology therefore in its modern form is a relatively new
discipline and uses
quantitative methods to study disease in human populations, to
prevent and control efforts,
Richard Doll and Andrew Hill, studied the relationship between
tobacco use and lung cancer,
there work was precede by experimental studies on the
carcinogenicity of tobacco tars and by
clinical observations.
Therefore success in epidemiology has played a great role in
eradication of small
pox; its elimination has contributed greatly to the health and well-
being of millions of people,
particularly in many of the poorest populations {Kostyrka&G,
2015}. Smallpox illustrates both
achievements and frustrations of modern public health. In the 1970 it
was shown that cowpox
infection conferred protection against the smallpox virus, yet it took
almost 200 years for the
benefits of this discovery to be accepted and applied throughout the
world{Kostyrka&G , 2015}. How epidemiology used in
eradicating small pox 3 The fact that there was no animal host was of
critical importance together with the low average