global burden fbpcbra.be/talks/bdevleesschauwer_iafwp_20170906.pdf · need for prioritization, risk...
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Rue Juliette Wytsmanstraat 14 | 1050 Brussels | Belgium
T +32 2 642 5035 | [email protected] | http://www.wiv-isp.be
Estimates of the global and
regional burden of foodborne
parasites as determined by the
World Health Organization
Brecht Devleesschauwer IAFWP International Symposium
Kuala Lumpur, Malaysia, 06/09/2017
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Foodborne Disease Burden Epidemiology
Reference Group (WHO/FERG)
WHO estimates of the global and regional burden of foodborne parasites
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Why estimate global burden of
foodborne disease?
• Full extent of foodborne disease (FBD) unknown
FBD outbreaks are highly visible, but true burden
remains invisible
FBD not a risk factor in studies on global burden of
disease
• Very many (potentially) foodborne hazards
not possible to monitor and control all of them at the
same time and level
need for prioritization, risk ranking
WHO estimates of the global and regional burden of foodborne parasites
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Challenges in estimating the
global burden of FBD
• FBD are complex: numerous hazards, numerous
health outcomes, effects on different time scales
• Food is not the only transmission pathway of many
food-related hazards
• Limited data availability, particularly in developing
countries
• Different methods for estimating disease burden due
to different hazards
WHO estimates of the global and regional burden of foodborne parasites
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Burden of disease
• How to define disease “impact” or “importance”?
• Disease have an impact on multiple aspects
Burden of disease = quantification of any of these aspects
This requires specific metrics
WHO estimates of the global and regional burden of foodborne parasites
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Burden of disease
• Which disease is most important?
Number of cases, number of deaths
Severity of case: duration, reduction quality of life
Severity of death: residual life expectancy
Summary Measures of Population Health
WHO estimates of the global and regional burden of foodborne parasites
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Disability-Adjusted Life Years
• 1 DALY = 1 healthy life year lost
• Summary measure of population health
Morbidity + mortality
Disease occurrence + disease severity
• DALY = YLD + YLL
YLD = Years Lived with Disability
= Number of incident cases×Duration×Disability Weight
YLL = Standard Expected Years of Life Lost
= Number of deaths×Residual Life Expectancy
WHO estimates of the global and regional burden of foodborne parasites
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Disability-Adjusted Life Years
DALY = YLD + YLL
YLD = Years Lived with Disability = N×D×DW
YLL = Years of Life Lost = M×RLE
WHO estimates of the global and regional burden of foodborne parasites
20 60 Age
DW
0
1
0
90
40 × 0.25
= 10 YLDs
30 × 1
= 30 YLLs
0.25
10 + 30 = 40 DALYs
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Disease models
Disease model, outcome tree
• Schematic representation of “health states”
acute, chronic stages
complications (sequelae, long-term health outcomes)
death
+ multiple severity levels
WHO estimates of the global and regional burden of foodborne parasites
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Disease models
WHO estimates of the global and regional burden of foodborne parasites
Toxoplasma gondii, congenital
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Global Burden of FBD
WHO/FERG methodology
• Systematic reviews
disease epidemiology, disease model
• Limited data statistical imputation models
• Complexity Disability-Adjusted Life Years
incidence perspective, hazard based
reference year 2010
disability weights: WHO/GHE
residual life expectancy: WHO/GHE standard (92)
• Multiple transmission pathways source attribution
(exposure, food) using structured expert elicitation
WHO estimates of the global and regional burden of foodborne parasites
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Global Burden of FBD
WHO/FERG scope
• 31 microbiological and chemical hazards
3 intestinal protozoa: Cryptosporidium spp.,
Entamoeba histolytica, Giardia spp.
1 invasive protozoon: Toxoplasma gondii
2 nematodes: Ascaris spp., Trichinella spp.
3 cestodes: Echinococcus granulosus, Echinococcus
multilocularis, Taenia solium
5 trematodes: Clonorchis sinensis, Fasciola spp.,
intestinal flukes, Opisthorchis spp., Paragonimus spp.
WHO estimates of the global and regional burden of foodborne parasites
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Global Burden of FBP
• 400 million illnesses (~20%)
• 90 million foodborne illnesses (~15%)
• 100,000 deaths (~10%)
• 50,000 foodborne deaths (~15%)
• 12 million DALYs (~15%)
• 7 million foodborne DALYs (~20%)
WHO estimates of the global and regional burden of foodborne parasites
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Global Burden of FBP
Cases (‘000) Deaths DALYs (‘000)
Giardia spp. (28 236) Taenia solium (28 114) Taenia solium (2 788)
Entamoeba histolytica (28 024) E. multilocularis (7 771) Paragonimus spp. (1 049)
Ascaris spp. (12 281) Clonorchis sinensis (5 770) Toxoplasma gondii (829)
Toxoplasma gondii (10 280) Cryptosporidium spp. (3 759) Ascaris spp. (605)
Cryptosporidium spp. (8 585) Opisthorchis spp. (1 498) Clonorchis sinensis (523)
Taenia solium (370) Entamoeba histolytica (1 470) E. multilocularis (312)
Paragonimus spp. (139) Ascaris spp. (1 008) Cryptosporidium spp. (296)
E. granulosus (43) Toxoplasma gondii (684) Opisthorchis spp. (188)
Clonorchis sinensis (32) E. granulosus (482) Intestinal flukes (155)
Intestinal flukes (19) Paragonimus spp. (250) Entamoeba histolytica (139)
Opisthorchis spp. (16) Trichinella spp. (4) Fasciola spp. (90)
Fasciola spp. (11) Fasciola spp. (0) E. granulosus (40)
E. multilocularis (8) Giardia spp. (0) Giardia spp. (26)
Trichinella spp. (4) Intestinal flukes (0) Trichinella spp. (0.6)
WHO estimates of the global and regional burden of foodborne parasites
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Global Burden of FBP
Cases (‘000) Deaths DALYs (‘000)
Giardia spp. (28 236) Taenia solium (28 114) Taenia solium (2 788)
Entamoeba histolytica (28 024) E. multilocularis (7 771) Paragonimus spp. (1 049)
Ascaris spp. (12 281) Clonorchis sinensis (5 770) Toxoplasma gondii (829)
Toxoplasma gondii (10 280) Cryptosporidium spp. (3 759) Ascaris spp. (605)
Cryptosporidium spp. (8 585) Opisthorchis spp. (1 498) Clonorchis sinensis (523)
Taenia solium (370) Entamoeba histolytica (1 470) E. multilocularis (312)
Paragonimus spp. (139) Ascaris spp. (1 008) Cryptosporidium spp. (296)
E. granulosus (43) Toxoplasma gondii (684) Opisthorchis spp. (188)
Clonorchis sinensis (32) E. granulosus (482) Intestinal flukes (155)
Intestinal flukes (19) Paragonimus spp. (250) Entamoeba histolytica (139)
Opisthorchis spp. (16) Trichinella spp. (4) Fasciola spp. (90)
Fasciola spp. (11) Fasciola spp. (0) E. granulosus (40)
E. multilocularis (8) Giardia spp. (0) Giardia spp. (26)
Trichinella spp. (4) Intestinal flukes (0) Trichinella spp. (0.6)
WHO estimates of the global and regional burden of foodborne parasites
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Global Burden of FBP
Cases (‘000) Deaths DALYs (‘000)
Giardia spp. (28 236) Taenia solium (28 114) Taenia solium (2 788)
Entamoeba histolytica (28 024) E. multilocularis (7 771) Paragonimus spp. (1 049)
Ascaris spp. (12 281) Clonorchis sinensis (5 770) Toxoplasma gondii (829)
Toxoplasma gondii (10 280) Cryptosporidium spp. (3 759) Ascaris spp. (605)
Cryptosporidium spp. (8 585) Opisthorchis spp. (1 498) Clonorchis sinensis (523)
Taenia solium (370) Entamoeba histolytica (1 470) E. multilocularis (312)
Paragonimus spp. (139) Ascaris spp. (1 008) Cryptosporidium spp. (296)
E. granulosus (43) Toxoplasma gondii (684) Opisthorchis spp. (188)
Clonorchis sinensis (32) E. granulosus (482) Intestinal flukes (155)
Intestinal flukes (19) Paragonimus spp. (250) Entamoeba histolytica (139)
Opisthorchis spp. (16) Trichinella spp. (4) Fasciola spp. (90)
Fasciola spp. (11) Fasciola spp. (0) E. granulosus (40)
E. multilocularis (8) Giardia spp. (0) Giardia spp. (26)
Trichinella spp. (4) Intestinal flukes (0) Trichinella spp. (0.6)
WHO estimates of the global and regional burden of foodborne parasites
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Regional Burden of FBP
WHO estimates of the global and regional burden of foodborne parasites
Africa Americas Eastern
Mediterranean Europe Southeast
Asia Western Pacific
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Where to go from here?
Limitations due to data availability & quality
• Not all foodborne parasites included
Anisakis, Trypanosoma cruzi, Taenia saginata, …
• Not all outcomes considered
toxoplasmosis and schizophrenia?
• Data gaps
particularly in low-income countries where burden is
highest !
WHO estimates of the global and regional burden of foodborne parasites
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Number of data gaps by country
From good estimates to better data !
WHO estimates of the global and regional burden of foodborne parasites
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Where to go from here?
DALYs only tell one part of the story
• Measures problems, not solutions
potential for health gain, unmet needs
does not replace cost-effectiveness studies!
• Health impact is just one of many aspects
WHO estimates of the global and regional burden of foodborne parasites
• economic impact
• rare, but severe
• stakeholder interests
• general awareness
• …
MCDA ??
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Conclusion
• WHO/FERG launched the most comprehensive
estimates of the global burden of FBP to date
• These address the lack of data to support food safety
policy making
• Despite data gaps and other limitations, the results
demonstrate a considerable burden
• Priority hazards differ between regions
• Control methods do exist for many hazards, and are
linked to economic development and effective food
safety systems
• Hazards of global significance need novel control
methods
WHO estimates of the global and regional burden of foodborne parasites
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Learn more
• WHO website http://www.who.int/foodsafety/areas_work/
foodborne-diseases/ferg/en/
• PLOS collection http://collections.plos.org/ferg2015
• Interactive tool https://extranet.who.int/sree/Reports?op=v
s&path=/WHO_HQ_Reports/G36/PROD/E
XT/FoodborneDiseaseBurden
• EURO-FBP Cost Action
http://www.euro-fbp.org/
WHO estimates of the global and regional burden of foodborne parasites
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Thank you
WHO estimates of the global and regional burden of foodborne parasites
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Rue Juliette Wytsmanstraat 14 | 1050 Brussels | Belgium
T +32 2 642 5035 | [email protected] | http://www.wiv-isp.be
Estimates of the global and
regional burden of foodborne
parasites as determined by the
World Health Organization
Brecht Devleesschauwer IAFWP International Symposium
Kuala Lumpur, Malaysia, 06/09/2017
![Page 25: Global Burden FBPcbra.be/talks/BDevleesschauwer_IAFWP_20170906.pdf · need for prioritization, risk ranking WHO estimates of the global and regional burden of foodborne parasites](https://reader035.vdocuments.net/reader035/viewer/2022081522/5f07399e7e708231d41bee75/html5/thumbnails/25.jpg)
FERG sub-regions
WHO estimates of the global and regional burden of foodborne parasites
AMR A
AMR D AMR B
AFR E
AFR D EMR D
EMR B
EUR C
EUR B
EUR A
SEAR D
SEAR B
WPR B
WPR A
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Imputation model
• Provide reasonable value + uncertainty range
• Bayesian random effects log-Normal regression model
• Only when data from different subregions available
If not: no imputation, no global estimates
• Model description
log(𝜃𝑖𝑗) ~ 𝑁𝑜𝑟𝑚𝑎𝑙(𝜇𝑖 , 𝜎𝑤2 )
𝜇𝑖 ~ 𝑁𝑜𝑟𝑚𝑎𝑙 𝜇0, 𝜎𝑏2
• 𝜃𝑖𝑗 = incidence in country 𝑗 belonging to region 𝑖
• 𝜇𝑖 = regional mean; 𝜇0 = global mean
• 𝜎𝑤2 = within-region variance; 𝜎𝑏
2 = between-region variance
WHO estimates of the global and regional burden of foodborne parasites
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Imputation model
• green countries: no imputation
• orange countries: 𝐿𝑁 𝜇𝑖 , 𝜎𝑤2
“random” country within concerned subregion
UI describes variability within subregions
• red countries: 𝐿𝑁(𝜇0, 𝜎𝑏2 + 𝜎𝑤
2 )
“random” country within a “random” subregion
UI describes variability between and within subregions
WHO estimates of the global and regional burden of foodborne parasites