surveillance for zoonotic diseases at wildlife-human interfaces in mainland southeast asia ·...
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Surveillance for Zoonotic Diseases at
wildlife-human interfaces in mainland
Southeast Asia
1
Why Zoonotic Disease Surveillance?
> 70% of emerging human pathogens are zoonotic
> 60% of emerging zoonoses have reservoirs in
wildlife
2
Increasing human populations
Increasing livestock
populations
Land use changes with infringement on wild
habitats (Jones et al, 2013)
Why is rate of zoonoses emergence
increasing?
3
Climate change (Jones et al, 208)
Increased demand for wildlife & wildlife products Wildlife Trade (Swift et al, 2007)
Ease and speed of global travel
4
Importance of Early Detection • Key to Control
• Reduction of Post-transfer Host Adaptation
• Potentially Lower Transmissibility
• Allows early sequencing to improve quality & speed
of diagnostics and preventive interventions
5
Traditional Outbreak Detection and Response
DAY
CA
SES
Adapted from J. Davis, Climate Adaptation Workshop, Nov. 2003
First
Case Detection/
Reporting
Lab
Confirmation
Response
Opportunity for control
6
DAY
CA
SES
First Case
Detection/
Reporting
Lab Confirmation
Response
Effective Health Early Warning
Surveillance, Observation
and Monitoring
Adapted from J. Davis, Climate Adaptation Workshop, Nov. 2003
Opportunity for control
7
USAID Emerging Pandemic Threats Program
Pathogen identification
Response and Prevention
In order to predict the emergence of novel infectious diseases in humans, pathogens must be
identified at their source.
Pro-active, risk based targeted surveillance and capacity building
8
9
Developing a Targeted Surveillance
Strategy
10
SMART surveillance
Strategic selection of geographic locations for surveillance
Strategic selection of species for surveillance
11
Why Conduct Surveillance in
Asia?
Jones et al, 2008
Hotspot regions for zoonotic disease emergence
(green = low risk yellow orange red = high risk
12
Spillover Risks: Southeast Asia
High demand for wild animal
meat and products
Rich biodiversity
Porous international borders with high volume
of informal and formal trade
Rapid economic development with
concurrent rural industrial development,
deforestation & large scale land-use change
-A 2013 global study assessing forest extent, loss and gain found
that Cambodia was one of the worst 3 countries in terms of
forest loss, with a loss of 7.1% of the country’s forests from 2000-
2012 (Hansen et al, 2013)
13
Wildlife Trade
Almost 30 million wild-caught CITES listed animals
traded from Se Asian countries from 1998-2007
(Nijman, 2010)
Lao P.D.R:
Wildlife consumed widely and traded openly in
markets: year long survey of 86 domestic markets
recorded >14,000 wild birds, >7,000 rodents, >3,000 bats.
International trade prevalent
Long, porous borders with 4 countries
Minimal wildlife trade law enforcement
14
Cambodia:
Wildlife, including primates, are consumed in many
rural communities & used in traditional medicine
Commercial trade moved underground:
surveillance must target middle-men and
confiscated wildlife
Large scale informal international
trade e.g. > 3 tons of rats/ day
to Vietnam for consumption
(Phnom Penh Post 2012)
Since 2001, the government’s Wildlife Rapid Rescue
Team confiscated > 56,000 animals from illegal
wildlife trade (Wildlife Alliance 2014)
15
Vietnam:
Wildlife consumption driven by greater
purchasing power of burgeoning middle-
class
Farming of various species in popularity
(porcupines to crocodiles to civets)
BUT many farm stock still sourced from the
wild (Brooks et al, 2010)
Key transit country for wildlife and wild
animal products en route to China
16
Increased relatedness to humans….
increasing risk of pathogen spillover?
Strategic selection of taxa for
surveillance
17
Increased contact rate… increased spillover risk
Henipaviruses
Lyssaviruses
Flaviviruses
Bunyaviruses
18
High proportion of viruses shared with
humans by bats, rodents and
primates compared with other taxa
19
Host Diversity
Disease Emergence
20
Animal Taxa 21
Risk-based Approach to Surveillance in hotspot regions
Sample along high risk disease transmission pathways
People have a high level of sustained and direct contact with these pathogens
22
• Hunting
• Markets/trade
• Wildlife/livestock
conflict
• Wildlife farms
• Extraction
• Land use change
• Global transportation
High risk disease transmission
interfaces
23
Flooded
forest Land
encroachment Bat farms
Indigenous
communities Villages
Local markets
Local
resort
24
Site Assessment Relationship Building
Sample Collection Sample Testing
25
What Samples?
Samples which reflect likely contact/
transmission route with humans
e.g. oral swab if saliva, rectal swab/ feces if
fecal, blood and organs if consumption
Analysis can help refine future surveillance
- Additional Ecological Information
- Animal Specific Information
26
Interfaces by country
27
Animals per Interface Interface # of Animals Sampled
Hunted 1819
For sale in market 180
For sale in restaurant 347
Private wildlife collection or pet 1
Rehabilitation center 8
Sanctuary 8
Wild animal farm 898
Zoo 4
Peri-domestic/in or near human dwelling(s) 177
Contact with tourists/ecotourism 153
Contact with domestic animals or humans NOT likely 2
Cambodia
Interface # Samples collected
Hunted 556
Markets 2107
Zoo 16
Peri-domestic 6
Contact with Tourists/ ecotoursim 1
Private sale 6
Private wildlife collection/ pet 1
Lao PDR
Interface # of Animals Sampled
For sale in large market (> 20 vendors) 372
For sale in restaurant 430
Private sale 189
Private wildlife collection or pet 2
Rehabilitation center 42
Sanctuary 8
Wild animal farm 58
Zoo 16
Peri-domestic/in or near human dwelling(s) 354
Contact with locals/religious site 10
Vietnam
28
Wildlife sampling sites Cambodia
29
Wildlife
sampling sites
Lao PDR
30
Wildlife
sampling sites
Vietnam
31
Samples per Taxa in Cambodia
Taxa Number of Animals Sampled
Carnivores 23
Other Taxa 6
Non-human Primates 211
Rodents & Shrews 450
Bats 2507
Birds 327
Ungulates 174
32
Samples per Taxa in Lao PDR
Taxa Number of Animals Sampled
Other Mammals 225
Non-human Primates 44
Rodents & Shrews 1460
Bats 957
33
Samples per Taxa in Vietnam Taxa Number of Animals Sampled
Other Mammals 2
Carnivores 97
Other Taxa 1
Non-human Primates 25
Rodents & Shrews 896
Bats 366
Birds 36
Ungulates 30
34
Summary of Sampling
35
- Mainly oral & rectal swabs
- Some tissue & blood samples
- Samples stored in Liquid N2
in field -80 freezer in
laboratory
- Consensus PCR approach
to screening
Direct sequencing
Next generation sequencing
where appropriate
Viral genus/ families targeted:
• Arenaviruses
• Astroviruses
• Bunyaviruses
• Coronaviruses
• Filoviruses
• Flaviviruses
• Henipaviruses
• Lyssaviruses
• Paramyxoviruses
• Rhabdoviruses
• Seadornaviruses
• Herpesviruses
• Influenzas
• Retrovirus - Lentivirus genus
• Simian Foamy viruses
Sampling and Diagnostics
36
Animal Host Priority Viral Pathogen Families
i. High Priority Species
Rodents Alpha, Arena, Astro, Filo, Flavi, Hanta, Henipa, Influenza A, Lyssa, Seadorna, Paramyxo, Pox, Bunya
Bats Flavi, Corona, Henipa, Rhabdo (Lyssa), Arena, Filo, Reo, Astro, Influenza A, Seadorna, Paramyxo, Bunya
Non-human Primates
Arena, Astro, Henipa, Influenza A, Entero, Retro, Filo, Flavi, Orthomyxo, Paramyxo, Pox, Herpes, Corona, Lyssa, Seadorna, Boca, Bunya
ii. Lower Priority Species
Carnivores Filo, Corona, Paramyxo, Filo, Arena, Parvo, Influenza, Rhabdo (Lyssa),
Ungulates Filo, Influenza, Rhabdo (Lyssa), Corona, Paramyxo, Pox, Bunya
37
Results so far…
**Currently no evidence of risk to human health posed by any of these viruses**
38
Building capacity for wildlife disease
surveillance Conducted surveillance in partnership with staff from
animal health, human health, forestry, and
environment sectors
Conducted workshops and field training on wildlife
surveillance for veterinary students and government
staff
Established viral family testing protocols and next
generation sequencing capacity in government
laboratories
39
Additional Monitoring
9 villages in 3 provinces
Surveyed quarterly to characterize contacts with
animals (domestic and wild) for 1 year
Recorded species and scale of wild animal
consumption
Identified high consumers and hunters of wildlife for
surveillance
Demonstrated demographic linkages
Identified reasons people avoid certain foods
does knowledge of health risks affect behaviour?
Cambodia: behavioral
40
Additional Monitoring
86 markets surveyed over 3 yrs: species, volume & prices
14,429 wild birds, 7398 rodents, 3573 bats, 927 reptiles, 403
carnivores, 236 individual + 665kg ungulates, 64 primates
(283 listed as VU, EN or CR on IUCN redlist)
3 month survey of key markets: biosecurity behaviours
e.g. butchering in market/ cleaning of utensils/ hand
washing/ species mixing etc
Identified 8 markets as posing higher risk of disease
spillover
Established recommendation for “healthy” markets
government guidelines
-Lao PDR: markets
41
Conclusions
Consensus PCR screening is a useful, cost-effective
approach for investigating viral diversity in wildlife
Surveillance at high risk interfaces can advise policy-driven preventative actions to activities
that increase risk of disease spillover from wildlife to
humans & threaten biodiversity: conservation,
human and ecosystem health benefits
Excellent buy-in for One Health approach in Se Asia
Capacity building concurrent to surveillance and
research is essential for sustainability
Main challenges to implementation are host
country government funding and human capacity
42
Acknowledgements United States Agency for International Development (USAID)
PREDICT
PREDICT Consortium: University of California Davis, Ecohealth
Alliance, Metabiota, Smithsonian Institution & Wildlife
Conservation Society
Institute Pasteur, Cambodia
National Veterinary Research Institute & Forestry
Administration of the Royal Government of Cambodia
Ministry of Agriculture, Forestry and Fisheries and National
Animal Health Laboratory, Lao PDR
Ministry of Agriculture and Rural Development, Department of
Animal Health, Vietnam, RAHO6 Vietnam, Hanoi University of
Agriculture National Key Laboratory of Veterinary
Biotechnology
43
Thanks! And one final tale….
Literature cited:
1)Brooks E., Roberton, S. & Bell, D. 2010. “The conservation impact of commercial wildlife farming of porcupines in Vietnam.” Biological
Conservation, 2010; DOI: 10.1016/j.biocon.2010.07.030
2)Jones, K., Patel, N., Levy, M., Storeygard, A., Balk, D., Gittleman, J., Daszak, P. 2008. “Global Trends in Emerging Infectious Diseases.
Nature Vol 451| 21 February 2008 doi:10.1038/nature06536
3)Jones, B., D. Grace, R. Kock, S. Alonso, J. Rushton, M. Said, D. McKeever, F. Mutua, J. Young, J. McDermott, and D. Pfeiffer. 2013.
Zoonosis emergence linked to agricultural intensification and environmental change. Proceedings of the National Academy of
Sciences 110: 8399-8404.
4)Hansen,, M.C., P.V. Potapov, R. Moore, M. Hancher, S. A. Turubanova, A. Tyukavina, D. Thau, S.V. Stehman, S. J. Goetz, T.R. Loveland,
A. Kommareddy, A. Egorov, L. Chini, C.O. Justice, and J.R.G. Townshend. 2013. High-resolution global maps of 21st-century forest
cover change. Science 342:850-853. doi: 10.1126/science.1244693.
5)Nijman, V. 2010. An overview of international wildlife trade from Southeast Asia. Biodiversity Conservation 19:1101–1114.
6)Phnompenhpost. 2012. Rat meat on the Menu at Vietnam border. Available at: www.phnompenhpost.com/lifestyle/rat-meat-menu-
vietnam-border. Accessed April 2014.
7)Swift, L., P. Hunter, A. Lees, and D. Bell. 2007. Wildlife trade and the emergence of infectious diseases. EcoHealth 4: 25–30.
doi:10.1007/s10393-006-0076-y.
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