JOHN SNOW CHOLERA

OUTBREAK:FACT OR FICTION?

T A K E T H I S Q U I Z T O S E E H O W M U C H Y O U K N O W A B O U T J O H N S N O W ’ S H I S T O R I C I N V E S T I G A T I O N O F C H O L E R A

I N 1 8 5 4 .

1. AT THE TIME OF THE DEVASTATING CHOLERA OUTBREAKS IN 19TH CENTURY LONDON, IT WAS A NEW DISEASE ABOUT WHICH LITTLE WAS KNOWN.

• True?• False?

1. AT THE TIME OF THE DEVASTATING CHOLERA OUTBREAKS IN 19TH CENTURY LONDON, IT WAS A NEW DISEASE ABOUT WHICH LITTLE WAS KNOWN.

FalseAlthough its etiology was unknown, over 700 books and pamphlets dealing with cholera were published in London during the time of the third pandemic (1839-1856). Most adhered to the prevailing thought, known as the miasma theory, that cholera was the result of a noxious form of bad air.

W H I L E T R U E T H AT T H E M I C R O S C O P I C O R G A N I S M V I B R I O C H O L E R A E W O U L D N O T B E I D E N T I F I E D U N T I L 1 8 8 3 , B R I T I S H D O C T O R S H A D B E E N T R E AT I N G C H O L E R A F O R H U N D R E D S O F Y E A R S . H O W E V E R , I T H A D B E E N S E A S O N A L A N D C A S E S W E R E G E N E R A L LY M I L D A N D C A M E T O B E K N O W N A S C H O L E R A N O S T R A ( “ O U R C H O L E R A” ) , A F T E R T H E M U C H M O R E V I R U L E N T “ I N D I A N ” C H O L E R A A R R I V E D I N T H E 1 8 3 0 S L I K E A P E N A N C E F O R V I C T O R I A N I M P E R I A L I S M .

Vibrio cholera

2. JOHN SNOW WAS A LONDON PHYSICIAN WHO WENT DOOR-TO-DOOR COLLECTING INFORMATION ABOUT DEATHS FROM CHOLERA, WHICH LED HIM TO IDENTIFY WATER AS THE LIKELY CAUSE OF THE OUTBREAK.

•True?•False?

2. JOHN SNOW WAS A LONDON PHYSICIAN WHO WENT DOOR-TO-DOOR COLLECTING INFORMATION ABOUT DEATHS FROM CHOLERA, WHICH LED HIM TO IDENTIFY WATER AS THE LIKELY CAUSE OF THE OUTBREAK.

FalseSnow’s investigation was guided by his already-developed theory that cholera is a localized disease of the gut and the likely route of transmission in this situation was drinking water.

S N O W W A S F O C U S E D O N T H E W E L L S F R O M T H E S TA R T, A N D W A S T O L D BY A C O M M U N I T Y R E S I D E N T T H AT T H E B R O A D S T R E E T P U M P H A D A B A D O D O R D U R I N G T H E H E I G H T O F T H E O U T B R E A K . H I S D ATA – A D D R E S S E S O F 8 9 FATA L C A S E S – C A M E F R O M T H E G E N E R A L R E G I S T E R O F F I C E , A N D H E U S E D T H I S T O M A K E D E TA I L E D I N Q U I R I E S D U R I N G T H E F I R S T P H A S E O F H I S I N V E S T I G AT I O N .

1849 Cholera prevention poster

3 . SNOW NOTED ALL THE CHOLERA DEATHS WITH BLACK HORIZONTAL BARS ON A MAP OF THE AREA, AND WAS ABLE TO USE THIS SPOT MAP TO PROVE TO THE BOARD OF HEALTH THAT THE BROAD STREET PUMP WAS THE CAUSE OF THE CHOLERA OUTBREAK.

•True?•False?

3. SNOW NOTED ALL THE CHOLERA DEATHS WITH BLACK HORIZONTAL BARS ON A MAP OF THE AREA, AND WAS ABLE TO USE THIS SPOT MAP TO PROVE TO THE BOARD OF HEALTH THAT THE BROAD STREET PUMP WAS THE CAUSE OF THE CHOLERA OUTBREAK.FalseNot only did Snow not use a map to discover the source of the outbreak, he also did not use a map of any kind in his presentations to the Board of Health. The famous map was created and used several months later as a persuasive illustration for the London Epidemiological Society.

F U R T H E R M O R E , A F T E R A D E C A D E P A S S E D , D R . E D W I N L A N K E S T E R , W H O L I V E D I N T H E A R E A A N D W H O H A D I N S T I G A T E D A M O R E T H O R O U G H I N V E S T I G A T I O N I N T O T H E O U T B R E A K A T T H E T I M E , S A I D O F S N O W ’ S W A T E R B O R N E / P U M P T H E O R Y : “ H E W A S N O T B E L I E V E D - - N O T A M E M B E R O F H I S O W N P R O F E S S I O N , N O T A N I N D I V I D U A L I N T H E P A R I S H B E L I E V E D T H A T D R . S N O W W A S R I G H T. B U T T H E P U M P W A S C L O S E D , N E V E R T H E L E S S , A N D T H E P L A G U E W A S S T A Y E D . ”

Dr. Edwin Lankester

4. REMOVING THE HANDLE OF THE BROAD STREET PUMP DID NOT STOP THE CHOLERA EPIDEMIC.

•True?•False?

4. REMOVING THE HANDLE OF THE BROAD STREET PUMP DID NOT STOP THE CHOLERA EPIDEMIC.

TrueDespite myths and urban legends, the cholera epidemic of 1854 was already waning when the Board of Health removed the handle of the Broad Street pump. Snow himself never made any such claims.

R e v . H e n r y W h i t e h e a d , a l o c a l c l e r i c w h o w o r k e d w i t h s n o w i n c o l l e c t i n g a n d a n a l y z i n g d a t a , p r e s e n t e d a p a p e r t o t h e E p i d e m i o l o g i c a l S o c i e t y o f L o n d o n i n 1 8 6 7 . H e u s e d a d a t a t a b l e t h a t s h o w e d t h e n u m b e r o f f a t a l a t t a c k s h a d f a l l e n f r o m 1 4 2 o n S e p t e m b e r 1 , 1 8 5 4 , t o 1 4 o n S e p t e m b e r 8 , t h e d a y t h e p u m p h a n d l e w a s r e m o v e d . H o w e v e r, h e e x p l a i n e d t h a t r e m o v i n g t h e p u m p h a n d l e s e r v e d t h e i m p o r t a n t f u n c t i o n o f p r e v e n t i n g a s e c o n d w a v e o f i l l n e s s . “ … I f t h e r e m o v a l o f t h e p u m p h a n d l e h a d n o t h i n g t o d o w i t h c h e c k i n g t h e o u t b r e a k w h i c h h a d a l r e a d y r u n i t s c o u r s e , ” h e s a i d , “ i t h a d p r o b a b l y e v e r y t h i n g t o d o w i t h p r e v e n t i n g a n e w o u t b r e a k , f o r t h e f a t h e r o f t h e i n f a n t , w h o s l e p t i n t h e s a m e k i t c h e n , w a s a t t a c k e d w i t h c h o l e r a o n t h e v e r y d a y o n w h i c h t h e p u m p h a n d l e w a s r e m o v e d . ”

Rev. Henry Whitehead

5. JOHN SNOW DID NOT FIND THE INDEX CASE – THE FIRST PERSON WITH CHOLERA WHO INITIATED THE OUTBREAK.

•True?•False?

5. JOHN SNOW DID NOT FIND THE INDEX CASE – THE FIRST PERSON WITH CHOLERA WHO INITIATED THE OUTBREAK.

TrueWhile working on an unrelated project 8 months later, Rev. Whitehead inadvertently came across a report of a 5-month old child who had died on September 2, 1854. The cause of death was listed as exhaustion after having diarrhea for 4 days; the onset of her symptoms and the length of her illness meant she was sick before anyone else. Previously it was believed that the epidemic started the night of August 31, when more than a dozen Soho residents came down with symptoms of cholera. Also, this child’s family lived in the house closest to the Broad Street pump.

W H I T E H E A D I N T E R V I E W E D T H E C H I L D ’ S M O T H E R A N D D I S C OV E R E D T H AT S H E H A D R I N S E D T H E B A BY ’ S D I A P E R S I N PA I L S O F WAT E R T H AT S H E E M P T I E D I N T O A C E SS P O O L I N T H E F R O N T O F T H E H O U S E .

1850s Punch magazine cartoon

To read more about the historic 1854 cholera epidemic and the community’s efforts to discover the cause, see “Map-Making and Myth-Making: John Snow Didn’t Solve the 1854 Cholera Outbreak with a Map,” at the Practical Playbook.

Sources:

S. P. W. Chave, B.A. HENRY WHITEHEAD AND CHOLERA IN BROAD STREET. Med Hist. 1958 Apr; 2(2): 92-108, 108-1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1034367/

“John Snow and Cholera,” a blog post at The Sick City Project by Richard Barnett, PhD. https://sickcityproject.wordpress.com/2013/03/11/john-snow-and-cholera/