John Snow and the 1854 Broad Street cholera outbreak — Transcript

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1. 0:00[MUSIC PLAYING]
2. 0:00[HORSE HOOVES CLOPPING]
3. 0:01ALYSSA GOODMAN: In 1854, cholera struck the city of London.
4. 0:06Over 600 people died in just a few weeks.
5. 0:09Physician John Snow is often credited with discovering
6. 0:13that cholera is a waterborne disease and with ending the 1854
7. 0:18epidemic by removing the handle from the contaminated Broad Street Pump.
8. 0:24The full story is much more interesting.
9. 0:27[MUSIC PLAYING]
10. 0:35So I've been reading about the John Snow Pub for years.
11. 0:39There it is.
12. 0:40Look at that.
13. 0:41Right here, on what used to be Broad Street, is this fine-looking pub.
14. 0:47There's this very inauspicious sign.
15. 0:50It says here, "The Red Granite kerbstone," over there,
16. 0:53"marks the site of the historic Broad Street
17. 0:55Pump associated with Dr. John Snow's discovery in 1854
18. 0:59that Cholera is conveyed by water."
19. 1:02So that's a really simple summary of the whole John Snow story.
20. 1:06And to give you just an overview, here's the story.
21. 1:09So it's 1854.
22. 1:11It's really hot and the end of the summer in London.
23. 1:14We're here is Soho, which was a very crowded neighborhood filled
24. 1:18of tenements with people not of a lot of means.
25. 1:21And there were a lot of people crammed into these buildings--
26. 1:24many, many people to an apartment.
27. 1:26And it's hot, and it's sweaty.
28. 1:28And the part that you can't imagine, looking right now-- because it's still
29. 1:31pretty crowded; it's not that hot, but it's still pretty crowded-- here,
30. 1:34the street now is completely clean.
31. 1:36We see street sweeping vehicles.
32. 1:38We see drainage in the streets.
33. 1:39We have sewers.
34. 1:40None of that was true in 1854.
35. 1:42Instead, the people who lived in these buildings, some of them
36. 1:45had cesspools in these little front courtyards.
37. 1:47And they would take their human waste and other waste
38. 1:49and just kind of throw it out the window into the cesspool
39. 1:52or bring it down to the cesspool.
40. 1:54And then it would drain wherever it drained.
41. 1:57And the street-- whoa-- was not something
42. 2:00that you could easily walk on and keep your feet clean.
43. 2:03Wow, that's slippery and disgusting.
44. 2:06And so people were used to this kind of somewhat disgusting ambiance.
45. 2:11And people thought that when there were terrible outbreaks of disease,
46. 2:14especially cholera, that it was caused by the very poisonous air
47. 2:18at this miasma, that they called it.
48. 2:21And the smell from all the poo and all the animal waste was pretty horrible.
49. 2:26And it was a pretty sensible theory to think
50. 2:28that that could be causing disease.
51. 2:30But John Snow, who lived not far from here--
52. 2:33we'll go there later-- was a physician in London,
53. 2:36who was convinced that cholera, in particular, was a waterborne disease.
54. 2:40It was not carried in this smelly air.
55. 2:43And what happened here on this spot in 1854
56. 2:46was that there was a baby who lived at number 40 Broad Street, which
57. 2:49would have been just about here, baby Lewis, who came down
58. 2:52with some sort of terrible disease that caused really terrible diarrhea.
59. 2:57And I think pretty quickly, people realized that it was cholera
60. 3:01and that there was going to be another outbreak of this very terrible disease.
61. 3:04And people started dying.
62. 3:09So what happens?
63. 3:10What happened was the waste from baby Lewis and other people
64. 3:14who became ill with the cholera-- so human vehicle matter--
65. 3:18mixed with the water supply that was in a relatively shallow well.
66. 3:22I think it was about 20 feet down under the street right here.
67. 3:25And then the cholera bacteria began to multiply.
68. 3:28And then people would ingest the water, which
69. 3:31provides the human intestines a place where the bacteria multiplied fast.
70. 3:36They need a host like that.
71. 3:38So anyway, when people ingest this contaminated water,
72. 3:42they come down with cholera from which you die in the hours to days.
73. 3:47And John Snow, who really was looking for a place
74. 3:51where he could, unfortunate circumstances as they were,
75. 3:54have a very concentrated outbreak of cholera
76. 3:56where he could study the origins of the outbreak,
77. 4:00was interested in helping the people but also interested immediately
78. 4:04in collecting information about what was going to happen in this outbreak.
79. 4:09So he would have come over here to this neighborhood
80. 4:11and started canvassing all the people around here to see who was dying
81. 4:14and who needed help and what they had done to possibly ingest water
82. 4:20from the various water supplies in the area.
83. 4:22And right here, at a location right near this red kerbstone,
84. 4:27was a source of what was apparently some very clean-tasting-- sweet-tasting,
85. 4:32actually, water for drinking.
86. 4:34Right here, it's called the Broad Street Pump.
87. 4:37And it turned out, as he started canvassing the neighborhood,
88. 4:40that he realized that most of the people who had fallen ill
89. 4:42and who were continuing to fall ill had drunk water from the particular pump.
90. 4:46So there were other water problems in the neighborhood.
91. 4:49And one of the things that we'll see later
92. 4:50is that, in the end, when he put all these data together and he made a map,
93. 4:54he had to show that this pump by walking was the closest to almost all
94. 4:59of the people who eventually died-- 600-something people died
95. 5:02in the epidemic.
96. 5:04So even though there are other pumps that are geographically
97. 5:06potentially nearer to those people, this one tasted good
98. 5:09and was close to the people who died by walking.
99. 5:14So in epidemiology today, it's known that one way to really make your case
100. 5:18is to have exceptions to the rules-- so people
101. 5:21who should have died, who didn't die, and then people who did
102. 5:24die for no apparent reason.
103. 5:26And so John Snow, in his work, actually found
104. 5:28both of those kinds of exceptions.
105. 5:30And so one case is what people sometimes refer to as the people who
106. 5:34were saved by the beer.
107. 5:36And so these were the brewery workers who worked a few blocks from here,
108. 5:39and drank mostly beer, and so had a clean supply of things to drink.
109. 5:45And the other case was the workhouse that was near here.
110. 5:47And these were the most indigent potentially people
111. 5:51in poorest of health.
112. 5:52And so why did they live?
113. 5:53They systematically survived this epidemic.
114. 5:56And part of the reason-- the main and the most important reason--
115. 5:59is that the workhouse had a well, had its own source of clean drinking water.
116. 6:04So there are the exceptions of people who should have died and didn't die.
117. 6:07And then what happened was he also found out
118. 6:09about a family who would bring water to a member of that family who
119. 6:14had moved far, a couple miles, outside of this neighborhood.
120. 6:17And they brought her some water, an elderly aunt.
121. 6:20And she and her niece drank it.
122. 6:23And those people both died.
123. 6:24So to us, looking at modern epidemiological methods,
124. 6:28John Snow had plenty of evidence to say that this water from this well
125. 6:33contained the contaminant that caused the disease.
126. 6:36But it still took actually many years until the locals believed his story.
127. 6:41And another thing that we should mention is that John Snow did not
128. 6:43collect all this data himself.
129. 6:45If you look around the street here, you'll
130. 6:47see that this is a very busy neighborhood
131. 6:49with lots and lots of people.
132. 6:50And I think it was even busier in 1854.
133. 6:53But it was a small contained community.
134. 6:56And there were people, for example like a curate, Henry Whitehead, who was
135. 7:01a local, who kind of knew everybody.
136. 7:03And so John Snow worked with Whitehead and with other people in the area
137. 7:08to really canvas the information and collect
138. 7:10the kind of sociological demographic information
139. 7:13that he needed to know who lived where, when they died, where they likely
140. 7:16got their water, who they talked to, who they came in contact with,
141. 7:20all kinds of other details about their personal lives.
142. 7:23And so that kind of human data collection,
143. 7:26in this tightly knit community, was also really, really important.
144. 7:31[MUSIC PLAYING]