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Avian influenza, pandemic influenza, ecohealth International Association for Ecology and Health, Kunming, October, 2012 A/Prof Colin D Butler National Centre for Epidemiology and Population Health, Dr Delia Grace ILRI

Avian influenza, pandemic influenza, ecohealth

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Presentation by Colin D Butler and Delia Grace at the Ecohealth 2012 conference held at Kunming, China on 15-18 October 2012.

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Avian influenza, pandemic influenza,

ecohealth

International Association for

Ecology and Health, Kunming, October, 2012

A/Prof Colin D Butler National Centre for Epidemiology and

Population Health,

Dr Delia Grace ILRI

Two views of Zoonotic Emerging

Infectious Diseases (ZEIDS)

• ZEIDs have been and continue to be one

of the most important issues in EH

• ZEIDs are less important than neglected

tropical zoonoses and divert resources

from tackling them

• Both views focus on the microbe rather

than the milieu

2

Warning! Contrarian views ahead

• H5N1 very unlikely to become a global

pandemic

• H5N1 very unlikely to establish in SSA

• Current EH side-stepping problems crucial

to our health and future

– Creation of continental-wide pathogenic milieus

– Difficult problems of equity and justice

3

Could H5N1 HPAI become the next

“mother of all pandemics”?

4

Margaret Chan: “three global crises .. on horizon” ..

Climate change

regional food shortages and soaring food prices

pandemic influenza

5

CGIAR report:

SARS: $50 - 100 billion

“major avian influenza pandemic “ > $1 trillion (Burns et al.

2008). $2 trillion (World Bank 2008).

6

milieu and microbe

Claude Bernard (1813-1878)

“Pathogenic tradeoff”

Pathogens “want” to reproduce

Effect on host not of concern:

Sometimes 1. hurt, don’t kill

2. don’t hurt

3. kill slowly

4. kill quickly

pathogen

reproduction

chance

enhanced

4. In comparison,

reproduction harder

trend to co-existence

7

Ewald P (2004). Evolution of virulence. Infectious Disease Clinics of

North America 18:1–15.

New milieus: different tradeoff?

pathogens in crowded host milieus that kill quickly have

- numerous other hosts to colonise

- hosts have high genetic similarity

- Immuno-suppressors and depressors

- LITTLE or No evolutionary penalty from rapid host

mortality

10,000 BCE -Neolithic transition: measles, smallpox, diptheria

1500-1600 - Americas: disease destroyed civilisation

1800s – Europe – industrialisation, urbanisation: White Plague

1900s – Africa – colonialisation, urbanisation: HIV, AIDS

8

9

Milieu and the

Adapted from Oxford et al Lancet Inf Diseases 2002; 2:111-4

2.5% global mortality (with bacterial co-infections)

Reasons to be sceptical of H5N1 pandemic

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1. More capacity to manage:

• Rapid global response (e.g. SARS)

• Numerous antibiotics for secondary bacterial infections

• Flu vaccines + anti-viral antibiotics

2. H5N1 case fatality rate questioned (Palese & Wang)

• If H5N1 develops human Ro >1 human lethality may fall (Ewald)

3. 1918 epidemic very atypical (c500 years human flu

epidemics)

• 1918 milieu extraordinary, unlikely to be coincidental

• Current milieu favours evolution of HPAI, but not HPHI

4. Vested interests exaggerate risk of H5N1 as human

pandemic

Could H5N1 HPAI establish in Sub

Saharan Africa?

11

Costard et al., RVC

HPAI would not have

established – even in the

absence of any control (Bett

et al., 2012 TED)

12

• HPAI in Nigeria: Epidemic occurred between Dec 2007 – Jul 2008

• Phylogenetic analysis shows the virus clustered in sub-lineages I, II. III and IV, indicating re-introductions (Fusaro et al., 2009)

• Theory of re-introduction supported by low R0 estimate : 0.7 – 1.1

• EID Surveillance – need to incorporate epi info/risk factors

Bo

ostr

ap

dis

trib

utio

n

Most costs associated with control, not

disease

13

Nigeria

•140 million people

•150 million poultry – 25% intensive systems

HPAI

•I.3 million chicken died or culled One person died

•80% people stopped eating chicken for up to 4 mths

•41% of farm workers lost jobs

•Most compensation went to larger farms

•Dead chickens widely consumed, Sick chickens widely

consumed, Vaccination probably used

•Around 100 million USD lost or spent

From emerging microbe to pathogenic milieu

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15

Sea Level: 1993-2012

Rainfall intensity : 1900-2011 Land-ocean temperature: 1880-2011

Earth system

observations

Arctic ice: 1979-2012

Million

Km 2

1998 2000 2004 2008 2011

Adapted from Murray & King, Nature. 2012; 481: 433-5.

Apparent production cap

2005: Plateau Oil

Production

(million barrels/day)

Oil price (US$ per

barrel)

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“IMF assessment of world recovery bleak”

October 9, 2012

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rapid public health response*

limited antimicrobial

resistance, but increasing

nutrition ok

public health breakdown

nutrition worse

living conditions worse

conflict increasing?

2012 20??

Could civilisation failure “breed” a

megapandemic?

* For diseases perceived as major threats to

developed countries

Sea level

rise

(future)

worse global

nutrition

failing

governance

Impaired

public

health

milieu for catastrophic

emerging diseases, e.g.

multi-drug –resistant TB,

artemisinin-resistant

malaria, HIV, others

Large-scale

population

dislocation

Climate

change

Rising food

prices

High

energy

costs

Dependence on fossil fuel,

declining in quantity, quality

and accessibility

Increased use

of crops for

fuel

conflict

Butler, in press (2012)

19

Less

climate

change Improved

governance

milieu for minor emerging

diseases, chronic

diseases, diseases of

ageing

Stable food

prices

Clean abundant energy

technologies, especially solar

Less

conflict

Better global education and

communication, slower

population growth, fairer

global society, new ways to

measure progress, new ways

of thinking,

less food waste, meat

consumption “contracts and

converges”

Improved

public health

Butler, in press (2012) 20

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Acknowledgements

6 “Di TRGIV: “Environment, agriculture and infectious

diseases of poverty”

Prof AJ McMichael (ANU)

Prof Xiao-Nong Zhou (China CDC)

WHO Technical Report

Also Bianca Brijnath, Adrian Sleigh

Special Programme for Tropical

Diseases Research

WORLD BANK

Summary

• H5N1 very unlikely to become a global

pandemic

• H5N1 very unlikely to establish in SSA

• Current EH side-stepping problems crucial

to our health and future

– Creation of continental-wide pathogenic milieus

– Difficult problems of equity and justice

22

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http://www.bodhi.net.au/html/forumforthefuture.html

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