Class 8: The agency of nature
Christos Zografos, PhD
Institute of Environmental Science & Technology (ICTA)
Universitat Autònoma de Barcelona, Spain
christos.zografos@uab.cat
Power, politics and environmental change
MA Environmental Humanities 2014-15
Masaryk University, Brno, Czech Republic

Introduction
•Main point: ecology makes political history
•Why you should know about it?
–Approach: complement structure, discourse, internalised practices, and human agency as sources of
(or ‘places to look for’) power
2

Class outline
•Class assignment
üClassroom exercise 1 – then I explain
üClassroom exercise 2 – then I explain
•Closing remarks
3

THE QUESTION
McNeill argues that although it is probably a rude blow to our species “lowly mosquitoes and
mindless viruses” have the power to shape human international affairs.
How did mosquitoes (A. aegypti) helped the Spanish Empire retain key fortifications in the
Caribbean against the attacks of other European powers (e.g. British, French, Dutch, etc.)?
4

Sub-question 1
•How did mosquitoes (A. aegypti) helped the Spanish Empire retain key fortifications in the
Caribbean against the attacks of other European powers (e.g. British, French, Dutch, etc.)?
•Get into two groups
q10 min to answer the question
q5 min (each group) to present your answer to class

BASIC ELEMENTS FOR ANSWERING QUESTION
•Yellow Fever: what is it?
•Yellow Fever: how was it introduced to America?
•Differential immunity
•Military implications of differential immunity
•Knowledge by observation

Yellow fever (YF)
•Yellow fever: lethal disease
–Until early 20th century: role of mosquitoes as disease vectors was found
•Virus vector (disease transmitter): females of Aedes Aegypti mosquito
–Other disease hosts: primates (humans, monkeys)
•Tropical and Sub-Tropical Africa & South America
•Incubation period: 3-6 days
•Most cases only a mild infection with fever, headache, chills, back pain, loss of appetite, nausea
and vomiting (lasts 3-4 days)
•But 15% enter 2nd toxic phase:
–recurring fever
–yellow skin colour (liver damage)
–abdominal pain
–‘Black Vomit’ (contains blood): caused by bleeding in mouth, eyes and stomach/intestines
•Toxic phase: fatal in approximately 20% of cases
•Surviving = life-long immunity
6
Aedes Aegypti Mosquito (source: www.memphishistory.org)

Yellow fever (YF)
•Introduced to America via mosquitoes brought from Africa with slave trade (16th-17th century)
–Humid & crowded conditions of ‘crossing’: help mosquito survive
•Role of local ecologies: plantation ecology of colonies + pre-existing swamps
–Water for incubation (e.g. barrels for drinking water storage)
7
A tobacco plantation (source: Public Broadcasting Service)

Differential immunity
•Mosquitoes and diseases wreck havoc but not indiscriminately: differential immunity (YF)
–If brought up as child in places where yellow fever common (endemic) then have some resistance and
less likely to fall ill or die when adult
•But if virus finds many organisms without anti-bodies becomes epidemic!
–Attacks those without immunity (to find hosts)
8

Military implications
•So, if all of a sudden you bring (e.g. in America) many non-immune bodies (e.g. people who have
grown up in places where there is no YF), virus (latent) finds space (human body) to expand ->
epidemic
–Such non-immune bodies: European soldiers (from Europe)
–Instead: African slaves + locally-born colonists/recruits + ‘seasoned’ troops: no space for
epidemic

9

Knowledge by observation – not science
•Colonial officials and aspiring attackers knew from observation (empirical knowledge) that this
happened
–Although did not know exactly ‘why’: the ‘Climate’
•Also knew that rains increased deaths
–More water for mosquitoes to reproduce
•…and that number of deaths would increase exponentially after 6-8 weeks
–Happily coincided with fortification durability!
•So, prepared themselves for a 6-8 week defence before letting YF “take its toll”
–Fortification and provisions + Soldiers
10

Example: Cartagena, 1741
•Role in Imperial trading system: first port of call for gold & silver convoys (until 1739)
•Commercial hub (hinterland): emeralds, sugar, cacao, cotton, botanical drugs, silver, gold,
pearls, timber, etc.
•Seat: naval & military establishment of Viceroyalty New Granada
–Colombia, Ecuador, Venezuela, Panama, Guyana, Costa Rica, Nicaragua, parts: Brazil and Peru
11

Battle for Cartagena (siege)
•Vernon’s fleet: largest amphibious expedition ever (after WWII Normandy)!
–186 ships + 29,000 soldiers (UK + N ‘US’)
•Cartagena defense:
–4,700: permanent battalion (‘fijo’) + local militia + Amerindian bowmen + sailors – Only 700 new
to environment
–6 ships
–Admirable fortifications
–Scarce: rifles, powder, food (Lezo)
•Series of delays resulted Brit (McNeill calculates)
–22,000 deaths/ 29,000 soldiers
–1,000 died in combat
•Compare this to:
–Brit army deaths in European war theatres = 8% deaths: wounds + disease
–ESP army: 200-600 deaths (no YF mention)
12
Blas de Lezo (source: Museo Naval de Madrid)
Edward Vernon, by Thomas Gainsborough (source: National Portrait Gallery)

Time is gold
•Series of delays resulted in siege lasting for 54 days (8 weeks approx.): YF takes toll!
•Intentional delays
–British: Wentworth wants to use orthodox siegeing methods to capture Bocachica forts (reduce them
one by one by erecting artillery batteries and open breaches for troops to go in): time-consuming
method
–Spanish: sink merchant vessels in navigable channels of bay
•Unintentional delays
–British: failure of original plan for Cathcart’s army to arrive in Cartagena by late December
(start of dry season) instead of late March (start of rainy season) – due to military inactivity
and corruption
13

Unintentional key factors
•“In an epidemiological irony … Cartagena’s defence was more secure because no large contingent of
reinforcements from Spain had joined the garrison
–“A few hundred reinforcements among an urban population of 10,000 who provided herd immunity gave
the yellow fever virus no foothold”
14

Sub-question 2
•McNeill argues that although it is probably a rude blow to our species “lowly mosquitoes and
mindless viruses” have the power to shape human international affairs
oWhy do we say, i.e. what is the proof and logic that shows that “lowly mosquitoes” have had a
political importance (“power to shape human affairs”)?
•Get into two groups
q10 min to answer the question
q5 min (each group) to present your answer to class

ELEMENTS FOR ANSWERING QUESTION
•The political importance of differential immunity: the fact that this has been changing, i.e.
first in favour then undermining the empire, is further proof that differential immunity (the
virus), hence the mosquitoes as well, have had a political importance
•Ecological conditions govern probabilities of success or failure of imperial project

•YF: crucial part of Spanish imperial defence
–Without it Spain would have lost much of her American empire in 18th century
–Same but vice versa for success of independence wars in 19th century Americas (e.g. southern parts
of US)
•Until 1770s, mosquitoes underpinned geopolitical order in Americas – after that they undermined
it!
16
Political importance of differential immunity

Human–environment: who has power?
•Ecological conditions that prevailed in colonies governed probabilities of success and failure
–Mosquitoes
–Plantation ecologies and swamps: mosquito incubator & habitat sites
•Lowly mosquitoes and mindless viruses can shape human international affairs
–Blow to our species, but true!
–
–Discuss? What implications of this? Do you buy in it?
17

THE ARGUMENT: PROF MCNEILL DISCUSSES BOOK "MOSQUITO EMPIRES”
http://www.youtube.com/watch?v=JzZpeisdmJ4
18

FINAL REMARKS
Part 3


Interaction of factors
•Ecology shaped history but it could do so as a result of accidents of history and environmental
change brought about by humans (agency)
–Slave trade brought yellow fever and malaria
–Disease environment of Caribbean: built/ cultural artefact (e.g. plantations)
–Haitian and American revolutionaries took stand, otherwise importance of differential immunity
would not materialise
–If doctors were more successful (earlier) -> erase effects of differential immunity: accidents,
luck
•“Humankind and nature make their own history together, but neither can make it as they please”
20

Human–environment: who has power?
•Quests for wealth and power (cultural factors) changed ecologies in Greater Caribbean
•But also: ecological changes shaped fortunes of empire, war, and revolution
•Viruses, mosquitoes, monkeys, parasites, swamps, as well as humankind make political history
21

Concluding remarks: disease and power
•With invention of yellow fever and malaria vaccines at end of 19th early 20th century
•Source of differential vulnerability changed
–“In this new world of effective vaccines and drugs”
–Rich and powerful societies capable of developing vaccines and inoculating their populations
–Became even richer and more powerful
•Source of power: from ‘nature’ (one’s own organism) to technology (external material affluence)
22
Source: http://yellowfever.lib.virginia.edu/reed/commission.html