human health risks at the animal-human interface
DESCRIPTION
Presented by Joachim Otte and Delia Grace at the Workshop on Asian Livestock: Challenges, opportunities and the Response, Bangkok, 16‐17 August 2012TRANSCRIPT
Asian Livestock
Challenges, Opportunities and the Response
August 16-17, 2012 Orchid Sheraton, Bangkok
Human Health Risks at the Animal-Human Interface
Joachim Otte & Delia Grace
2
Overview
• Asia’s growing food demand
• Asia’s livestock sector response
• Infectious and parasitic disease dynamics
• Impacts of zoonotic diseases
• Response elements
3
Global Human Population: 2000BC – 2010AD
Source: IUCN/WWF Living Planet Report
App. 1850
1950: 2.6 bln
2050: 9.3 bln
4
Billion
Meat & Dairy Expenditure Density
Source: PPLPI (2008)
5
Income Growth: China & India
0
20
40
60
80
100
Dev'ping Dev'ped
Non-food
Other food
Fish
Milk
Meat
Fruit
Cereals
Income in $2005PPP Allocation of additional $
6
Poultry Meat Demand Growth 2000-2030
Source: Robinson and Pozzi (2011)
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Egg Demand Growth 2000-2030
Demand growth in kg per sqkm
Source: Robinson and Pozzi (2011)
Dairy Demand Growth 2000-2030
Demand growth in kg per sqkm
9
Source: Robinson and Pozzi (2011)
Livestock Sector Growth & Development
• Growth in total number of livestock
• Relative growth in importance of poultry and pigs vs ruminants
• Faster turnover / increased throughput (intensification) – Increased use of high-
density feeds
– Genetic selection
• Larger farming units and concentration of units
• Increased use of feed ‘additives’
• Stratification of sector and vertical integration / contract farming
• Longer, cross-border supply chains
10
East Asia Southeast Asia
Growth in Poultry Meat & Poultry Numbers, 1990-2010
11
FAO Regional Office for Asia and the Pacific
‘High Tech.’ ‘Intermediate Tech.’ ‘Low Tech.’
Pro
du
cti
on
P
rocess
ing
R
eta
il
12
System Co-existence
Ecological Consequences • Land use change leads to habitat fragmentation
and growing interfaces
• Expansion of irrigated areas provides new habitats for waterborne organisms and insect vectors
• Large, housed, rapid-turnover genetically homogenous farmed animal populations and heavy use of antimicrobials provide new eco-system and selective pressures
• Complex value chains provide novel transmission pathways
13
FAO Regional Office for Asia and the Pacific
Building Bridges, Supporting Livelihoods
Pathogen Reservoirs, Interfaces & Dynamics
Pathogen dynamics
• Territorial expansion / invasion
• Within species fitness / virulence shifts
• Species‘jumps’
Wildlife ‘pool’
Human ‘pool’
Domestic animal ‘pool’
• Direct exposure / contact • Indirect exposure / contact
14
15
Host & Lineage Origins for the Gene Segments of the 2009
A(H1N1) Virus
Source: RJ Garten et al. Science 2009;325:197-201 16
Example: Avian Influenza Virus
• Species ‘jump’
– Wild waterfowl domestic poultry humans & cats
• Virulence shift
– LPAI HPAI (Italy, Holland, Canada, Chile, China, Mexico)
• Territorial expansion
– HPAIV H5N1 affected > 60 countries on 3 continents and has become endemic in 5 or 6 countries
17
FAO Regional Office for Asia and the Pacific
Selection for Virulence
• Mode of transmission:
– (i) horizontal ; vertical
– (ii) indirect ; direct
• Host homogeneity
• Host cluster connectivity
• Within-host strain competition
• Vaccination or
• Culling
• Treatment or
Sources: Galvani 2003, 2008
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Antimicrobial Use
19
AM Use USA (Total 17,500 tonnes)
AM Use (kg/tonne meat)
Resistance of Non-typhoidal Salmonella enterica Isolates to
Antibiotics
20
Genetic Exchange Among Bacterial Species
21 From Silbergeld et al., 2008
Zoonotic Disease Impacts / Costs
• Income foregone through reduced economic activity
• Cost of precautionary and preventive measures
• Cost of control activities
• Reduced productivity and welfare in humans and animals through disease burden itself
22
SARS Impact on Global Travel, Hong Kong
23
Cost of SARS: Initial Estimates, ADB
7 6 5 4 3 2 1 0
Hong Kong
China, mainland
Taiwan
South Korea
Indonesia
Singapore
Thailand
Malaysia
Philippines US$ billion
4%
0.5%
1.9%
0.5%
1.4%
2.3%
1.6%
1.5%
0.8%
% of GDP
24
Human Cases and Estimated ‘Cost’ of ‘New’ Zoonoses
25
Compiled in WB, 2012
BSE UK (1986 to 2009): 15.5 billion US$ (<200 human cases) BSE US (2003 to 2007): 11.0 billion US$ (no human case)
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1 Approximately 1/3 foodborne
Burden of Selected ‘Endemic’ Zoonoses (DALYs / 100,000)
27
Cost of Antimicrobial Resistance
• Longer hospitalization (11 days)
• Increased treatment cost (US$20,000)
• Higher case fatality rates (2.2 fold)
• In a US-study increased cost of US$10,000 per hospitalized case
• General therapy shift to more expensive drugs (even for non-AMR-resistant cases)
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Veterinary Public Health Priorities
• Reduce incidence of food-borne diseases and parasite infestations (E.Asia & SE.Asia)
• Reduce risk of novel ‘emerging’ zoonoses and detect these early
• Promote prudent use of antimicrobials in farm animals
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Response Elements
1. A holistic, multidisciplinary approach to
agriculture and health research and risk
management (horizontal cooperation and
coordination).
2. Address the root causes of disease burdens
/ risk (more prevention, less reaction).
3. Improved (supra-)national early warning
/disease reporting systems and disease
control (vertical cooperation and
coordination).
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