Epidemic Diseases Epidemic Diseases of the 19of the 19thth Century Century

The Demographic The Demographic ContextContext

• 1919thth century experienced explosion century experienced explosion of endemic & epidemic diseasesof endemic & epidemic diseases

• Related to:Related to:– IndustrializationIndustrialization– UrbanizationUrbanization– Trade activitiesTrade activities– Military activitiesMilitary activities

• Factors were similar to the Middle AgesFactors were similar to the Middle Ages• Scale of these changes exponentially Scale of these changes exponentially

greatergreater

• Britain first country to experience Britain first country to experience industrializationindustrialization

• Associated with:Associated with:– Significant population growthSignificant population growth– Significant migration to urban centresSignificant migration to urban centres

• Explosive growth of cities Explosive growth of cities outstripped their infrastructuresoutstripped their infrastructures– Water supplyWater supply– SewageSewage– HousingHousing

• Manchester is an exampleManchester is an example

Population Growth in Manchester

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

17171758177318011821183118411851

• Northern industrial cities such as Manchester Northern industrial cities such as Manchester & Liverpool grew faster than London& Liverpool grew faster than London

• Result was horrific living conditions for the Result was horrific living conditions for the working classworking class

• Subject of many studiesSubject of many studies– Chadwick: Chadwick: Report on the Sanitary Conditions . . .Report on the Sanitary Conditions . . .

(1842)(1842)– Engles: Engles: Condition of the Working Class . . .Condition of the Working Class . . .(1844)(1844)– Mearns: Mearns: Bitter Cry of Outcast London . . .Bitter Cry of Outcast London . . .(1883)(1883)

• Emergence of statistics helped Britons Emergence of statistics helped Britons “see” the impact of urbanization“see” the impact of urbanization

• William FarrWilliam Farr– Prominent epidemiologistProminent epidemiologist– 22ndnd Registrar General of the Central Board of Registrar General of the Central Board of

HealthHealth– Instituted systematic collection of vital Instituted systematic collection of vital

statisticsstatistics– Developed many statistical methods still in Developed many statistical methods still in

use todayuse today

• Farr’s 1843 Report concluded that urban Farr’s 1843 Report concluded that urban life expectancy was lower than rural life life expectancy was lower than rural life expectancyexpectancy– Average national life expectancy: 41 yearsAverage national life expectancy: 41 years

• Rural Surrey: 46 yearsRural Surrey: 46 years• London: 36.7 yearsLondon: 36.7 years• Liverpool: 25.7 yearsLiverpool: 25.7 years

– Highest mortality in children under age 5Highest mortality in children under age 5• ½ of all children in Liverpool dead by 5½ of all children in Liverpool dead by 5thth birthday birthday• In Surrey, ½ dead by age 50In Surrey, ½ dead by age 50

• Several diseases emerged as Several diseases emerged as significant threats to health during significant threats to health during this timethis time– CholeraCholera– TBTB– Typhoid FeverTyphoid Fever

The Medical ContextThe Medical Context

• Most physicians & influential lay Most physicians & influential lay people believed that epidemic people believed that epidemic diseases were caused by miasmadiseases were caused by miasma

• Literally “pollution”Literally “pollution”• By 19By 19thth century, understood as century, understood as

poisonous air filled with particles poisonous air filled with particles from decomposed matterfrom decomposed matter

• Night air was considered worseNight air was considered worse

• Idea originated in Hippocratic timesIdea originated in Hippocratic times• By 19By 19thth century, a few diseases century, a few diseases

recognized as contagiousrecognized as contagious– SmallpoxSmallpox

• Most were notMost were not

Contagion TheoryContagion Theory Miasma TheoryMiasma Theory

SourceSource A material substance A material substance (animal matter)(animal matter)

Required index caseRequired index case

Foul airFoul air

Disease generation Disease generation could be spontaneouscould be spontaneous

Mode of TransmissionMode of Transmission Person to personPerson to person

Contaminated water?Contaminated water?Local environmental Local environmental conditionsconditions

Some localities more Some localities more prone to the problemprone to the problem

Seasonal variationsSeasonal variations

Signs & SymptomsSigns & Symptoms Specific to each Specific to each disease?disease?

Different symptoms Different symptoms could be observedcould be observed

SusceptibilitySusceptibility Attacked individual only Attacked individual only once?once?

Attacked individuals Attacked individuals repeatedlyrepeatedly

Conditions Conditions Determining End of Determining End of OutbreakOutbreak

Not well understood.Not well understood.

Should be when Should be when everyone was deadeveryone was dead

Removal of source of Removal of source of miasmamiasma

• Miasma theory supported by many Miasma theory supported by many prominent 19prominent 19thth century health reformers century health reformers– William FarrWilliam Farr– Florence NightingaleFlorence Nightingale

• Made more sense given the knowledge Made more sense given the knowledge of the timeof the time

• Under girded the sanitary emphasis of Under girded the sanitary emphasis of the 1the 1stst era of the public health era of the public health movementmovement

• Miasma theory also supported by Miasma theory also supported by business community & politiciansbusiness community & politicians

• Would make quarantine unnecessaryWould make quarantine unnecessary• This kept international trade & This kept international trade &

military activity goingmilitary activity going

CholeraCholera

• An important example of a disease that An important example of a disease that successfully moved out of its original successfully moved out of its original geographic locationgeographic location

• ““concentrated people’s minds” concentrated people’s minds” (Porter)(Porter)

• Cause: bacteria Vibrio choleraeCause: bacteria Vibrio cholerae• Severe diarrheal disease spread Severe diarrheal disease spread

through contaminated waterthrough contaminated water

• Death can occur within hoursDeath can occur within hours• Victims were frightening to beholdVictims were frightening to behold

– Complete loss of control of bodily Complete loss of control of bodily functionsfunctions

– Shock, circulatory collapseShock, circulatory collapse– Bodies almost blackBodies almost black

• Disease is endemic to IndiaDisease is endemic to India• Often spread by religious pilgrimagesOften spread by religious pilgrimages

• Always burned outAlways burned out

• In 19In 19thth century, the difference was century, the difference was presence of Europeans in Indiapresence of Europeans in India

• Spread to Europe, Asia & Africa Spread to Europe, Asia & Africa along trade & military routesalong trade & military routes

• 11stst pandemic (1816-18) pandemic (1816-18)– overland to Nepal, Afghanoverland to Nepal, Afghan– by sea to Asia, Africaby sea to Asia, Africa

• 22ndnd pandemic (1826-1832) pandemic (1826-1832)– to Russia 1831to Russia 1831– Europe, winter of 1831-32Europe, winter of 1831-32– Canada, New York, 1832Canada, New York, 1832– Pacific coast, 1834Pacific coast, 1834

• Panic in Europe’s major citiesPanic in Europe’s major cities• No one knew what caused itNo one knew what caused it

– Churches viewed it as a moral issueChurches viewed it as a moral issue– Others believed it was miasmaOthers believed it was miasma

• Physicians emphasized protection of Physicians emphasized protection of individual constitutionsindividual constitutions

• 33rdrd pandemic (1852-60) pandemic (1852-60)– Worst impact in RussiaWorst impact in Russia

• 44thth pandemic (1863-75) pandemic (1863-75)– Mostly Europe & AfricaMostly Europe & Africa

• During 3During 3rdrd pandemic, debate pandemic, debate between advocates of miasma & between advocates of miasma & contagion crystallizedcontagion crystallized

• Major figure of this era was John Major figure of this era was John Snow (1813-58)Snow (1813-58)

• Snow spent many years thinking Snow spent many years thinking about cholera prior to 1854 about cholera prior to 1854

• In 1831, as a medical student, cared In 1831, as a medical student, cared for coal miners sick with cholera for coal miners sick with cholera near Newcastlenear Newcastle– Later speculated that it was spread by Later speculated that it was spread by

invisible entities on their handsinvisible entities on their hands

• Living in London by 1848 when Living in London by 1848 when cholera struck againcholera struck again

• Investigated origins of this outbreakInvestigated origins of this outbreak• Again proposed contagion as reason Again proposed contagion as reason

for spreadfor spread• Speculated that contaminated food Speculated that contaminated food

or water might spread the diseaseor water might spread the disease

• Published these ideas in 1849Published these ideas in 1849• Provided evidence to support themProvided evidence to support them

• Snow’s hypothesis not well receivedSnow’s hypothesis not well received• Always alternative, more plausible Always alternative, more plausible

explanationsexplanations

• 1854 cholera outbreak in London1854 cholera outbreak in London• Snow suspected spread was due to Snow suspected spread was due to

contaminated watercontaminated water• Perfect natural experiment existed in Perfect natural experiment existed in

the district where he was workingthe district where he was working

• 2 different water companies supplied 2 different water companies supplied water to the districtwater to the district– One drew water from contaminated section One drew water from contaminated section

of the Thames River (Southwark & of the Thames River (Southwark & Vauxhall Co.)Vauxhall Co.)

– One drew water from above the sewage One drew water from above the sewage outlets (Lambeth Co.)outlets (Lambeth Co.)

• Snow traced local victims & determined Snow traced local victims & determined who had consumed water from which who had consumed water from which sourcesource

• Statistical analysis indicated 71:5 Statistical analysis indicated 71:5 ratio of deaths from Southwark & ratio of deaths from Southwark & Vauxhall as opposed to LambethVauxhall as opposed to Lambeth

• Results still not acceptedResults still not accepted• Alternative theories proposed by Alternative theories proposed by

supporters of miasmasupporters of miasma

• In late August, cholera broke out in In late August, cholera broke out in SohoSoho

• Water companies supplying water Water companies supplying water had a clean sourcehad a clean source

• Snow speculated that a pump on Snow speculated that a pump on Broad St. might be contaminatedBroad St. might be contaminated

• Initial investigation of pump proved Initial investigation of pump proved negativenegative

• Snow mapped all cholera victimsSnow mapped all cholera victims• Used this evidence to persuade Used this evidence to persuade

removal of the handle of the Broad removal of the handle of the Broad St. pumpSt. pump

• Epidemic stoppedEpidemic stopped

• Subsequently, source of Subsequently, source of contamination foundcontamination found

• Several points must be made about Several points must be made about Snow’s contributions to germ theorySnow’s contributions to germ theory– He was often unwilling to go head to head He was often unwilling to go head to head

with colleagues who supported miasmawith colleagues who supported miasma– He beat William Budd by 10 days in He beat William Budd by 10 days in

publishing his theory of the spread of publishing his theory of the spread of choleracholera

– Cholera bacillus was seen under a Cholera bacillus was seen under a microscope in 1854 by Fillipo Pacini, whose microscope in 1854 by Fillipo Pacini, whose findings were not translated into Englishfindings were not translated into English

• William Farr proposed an equally William Farr proposed an equally plausible theory (for the times) as to plausible theory (for the times) as to why cholera deaths were why cholera deaths were concentrated near the Thames Riverconcentrated near the Thames River

• Some historians argue that Farr Some historians argue that Farr contributed far more to contributed far more to epidemiology than did Snowepidemiology than did Snow

• Snow just happened to be correctSnow just happened to be correct

• By 1860s, germ theory acceptedBy 1860s, germ theory accepted• V. cholerae “rediscovered by Koch in V. cholerae “rediscovered by Koch in

18841884