1. Reducing transmission in the food chain
Delia Grace
International Livestock Research Institute, Kenya
Short course on Antimicrobial resistance: A multidisciplinary approach
London School of Hygiene and Tropical Medicine
18 July 2019
Monday 15th – Friday 19th July 2019
2. Learning objectives
1. Get an overview of global livestock and fish value chains
2. Understand use of AM in global livestock/fish production and its trends
3. Understand the drivers of AM use in the food chain
4. Identify a business case for reduction of AM transmission in food chains
5. Review some successes in reducing AM transmission
5. What the world eats – grams per day
0 500 1000 1500 2000 2500
Africa
Southern Asia
South east Asia
China
Europe
Food types (gram per capita per day)
Livestock
Fish
Cereals
Pulses
Tree nuts
Vegetables
Fruits
Oils
Starch roots
Sugars
Europeans eats five times as much LP as Africans
6. What the world eats: protein
0
20
40
60
80
100
1961
1971
1981
1991
2001
2011
1961
1971
1981
1991
2001
2011
1961
1971
1981
1991
2001
2011
1961
1971
1981
1991
2001
2011
1961
1971
1981
1991
2001
2011
Dailypercapitaproteinsupply
(g/cap/day)
Animal Fish Vegetal
World Europe South-Eastern Asia Southern Asia sub-Saharan Africa
Courtesy Mats Lannerstad. Grace et al. (upcoming)
Daily per capita
protein supply
Annual per
capita protein
supply
0
10
20
30
40
50
60
70
80
90
100
1970 1980 1990 2006 2030 2050
Annualpercapitasupply
(Kg/person/yr)
World
pulses, dry
meat
milk and dairy (exc. Butter)
1970 1980 1990 2006 2030 2050
Sub-sarahan Africa
1970 1980 1990 2006 2030 2050
South Asia
7. Where the food comes from
Source: Options for the Livestock Sector
in Developing and Emerging Economies
to 2030 and Beyond. World Economic
Forum White Paper January 2019
8. Future trends in livestock/fish productionProduction(millionsoftonnes)
LMICs
Year
HICs
9. Reducing……… transmission in
the food chain
a) antimicrobial residues
b) antimicrobial resistant pathogens
c) antimicrobial resistant microbes
10. Causes of foodborne disease
0
5,000,000
10,000,000
15,000,000
20,000,000
25,000,000
Microbes Helminths Aflatoxins Other toxins
Burden in developing countries in DALYs
per year
zoonoses
non
zoonoses
Havelaar et al., 2015
12. Antimicrobial use in livestock
• Total consumption in the livestock
sector in 2010 estimated at 63,151
tons
• Global antimicrobial consumption
will rise by 67% by 2030
• It will nearly double in BRICS
nations
• More than 73% of all
antimicrobials sold in the world
are used in animals
13. Where AM are used in food chains
Source: Van Boeckel et al. (2015)
Global antimicrobial consumption in livestock
(mg per 10km pixel)
14. 14
Antibiotic use: Vietnam
Livestock farmers
• 45 antibiotics from 10 classes
• 100% industrial farmers treat
themselves; 60% of household
farmers
Cuong et al al., 2015
15. Can we regulate our way to reduce transmission?
• Salbutamol – ‘growth promoter’ in
pigs
• Clearly illegal in Vietnam
• High concern of authorities and
consumers
• Easy to test for
In 2015, 6,000 kg salbutamol imported and sold:
10 kg had a legitimate medical use (Van Duan & Huong 2016)
11% of packaged feed and 4% of pork pooled samples were
positive for chloramphenicol, a banned substance; (Tuyet-Hanh et
al, 2017)
21. • Animal disease is a key constraint:
Billions die each year from preventable & curable disease
• As livestock systems intensify in developing countries,
diseases may increase
Young Adult
Cattle 22% 6%
Shoat 28% 11%
Poultry 70% 30%
Otte & Chilonda,
IAEA
Annual mortality of African livestock
( Around half due to preventable or curable disease )
Are there downsides if we reduce use in livestock and
fish?
23. • How much human AMR comes from agriculture?
• What interventions could reduce use in agriculture?
• What are the costs and benefits of these interventions?
What are the un-intended consequences?
Are interventions feasible?
• What effect does the intervention have on human AMR?
• What effect does the intervention have on human and
animal well-being?
What should we do about AM in food chains?
24. What we know
HIC LMIC
How much AMR from agriculture? Certainly a little,
maybe more
Don’t know
Interventions shown to reduce AMU at scale Yes No
Interventions are affordable Yes Don’t know
Interventions are feasible Yes Maybe not
Un-intended negative consequences Likely small May be large
Interventions appreciably reduce AMR in people Don’t know Don’t know
Effect on human and animal overall well-being Don’t know Don’t know
25. Evidence gaps on Ag AMU
21 acceptable studies
No RCTs, most farm workers, most non-pathogen
24% reduction in AMR in people
26. Reducing transmission in food chains
• Customer pressure, societal will
• Legislation, regulation, enforcement
• More rational use of antimicrobials
• Alternatives to antimicrobials
– Phages, pro-biotics, heavy metals
• Obviating need for antimicrobials
– Vaccines, management, genetics
30. 30
Randomized
Lost to follow up at two weeks
Villages=0 Farmers=11
Sick cattle= 51
Allocated to control
Villages =23 Farmers =226
Sick cattle identified by farmers=475
Lost to follow up at two weeks
Villages=0 Farmers=20
Sick cattle =51
Allocated to intervention
Villages =23 Farmers =218
Sick cattle identified by farmers=450
Data analysis
Control Villages=23
Farmers=208 full, 16 some, 2 none
Sick cattle = 401 full, 23 some, 51 none
Data analysis
Test Villages=23
Farmers=197 full, 18 some, 3 no
Sick cattle=377 full, 22 partial, 51 none
Allocation
Follow-up
Analysis
Followed CONSORT
31. 31
Results
• 1. Greater knowledge increase 30 points vs 8
Diagnostic signs 84% intervention vs. 57% control)
• 2. Better practice 16 ml vs. 12 ml
• 3. Better clinical outcomes
Failure 1% vs 2%; SA 15% vs. 25%
• 4. Benefits both short and mid term.
• 5. No overall increase in drug use
32. A hopeful intervention
Launched during partner event, 21/22
February in Nairobi
Antimicrobial
Resistance
Hub
www.amr.cgiar.org
33. AMR in the CGIAR: Activity focus
Partnerships
AM use and
value chains
Transmission
dynamics
Interventions
Enabling
policy
Capacity
35. Conclusions 1
AM usage in animals:
• likely to lead to resistance in animal
pathogens
• Likely to lead to increase circulation of
resistant strains of zoonotic pathogens
(especially foodborne pathogens)
• Possibly, but rarely demonstrated, could
lead to resistance of human pathogens
(not zoonotic). Only demonstrated in
few cases.
• For human pathogens – it is unlikely the
primary source of resistance comes
from AM use in animals.
36. • Animal agriculture uses more AM than human health
does and is rapidly trending up
• Most use and most growth in use is in LMIC
• Dual challenge: access as well as excess
• AMR is not the only externality of disease in LMIC and
trade-offs need to be examined
• Evidence should under-pin a business case but is
mostly lacking for LMIC
• Yet there is a strong rationale for One Health as the
best approach for solving cross-sectoral challenges
Conclusions 2
37. This presentation is licensed for use under the Creative Commons Attribution 4.0 International Licence.
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