Transcript Document

Vector-borne Disease Surveillance in Southeast Asia –
Challenges and Opportunities in Vector Collection and
Pathogen Detection
MAJ Brian Evans, Ph.D.; Jim McAvin; Alongkot Ponlawat, PhD; Ratree
Takhampunya, PhD; LTC Jason Richardson, PhD
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Agenda
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Mission
Intelligence requirements
PM detachment capabilities
Detection capabilities (JBAIDS)
Value of pathogen assays
Where is the gap?
Conclusion
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Mission
To accurately asses the risk of vector-borne
disease in an AO and to recommend/
implement measures that reduce the
disease threat among soldiers.
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Intelligence Requirements
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Human case data
Vector data (presence/absence)
Pathogen data (presence/absence)
Environmental data
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
PM Detachment Capabilities
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Pre-deployment intelligence
Gather case data (non-specific/specific)
Limited vector surveillance
Limited or no pathogen detection
capability.
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Detection Capability
JBAIDS Assay
GRI Rank*
Activities Underway
Comments
Dengue virus
5
Deployed Vector
Surveillance
AFPMB Approved
Chikungunya virus
6
Wet Assay Optimization
Funded: Pending FY10 Award
Aedes aegypti mosquitoes
not ranked
Deployed Vector
Surveillance
AFPMB Submission Planned
Leishmania spp
50
Deployed Vector
Surveillance
AFPMB Approved
Leishmania visceral genotype
20
Deployed Vector
Surveillance
AFPMB Approved
Leishmania human
pathogenic spp
Various
Wet Assay Optimization
Funded: Pending FY10 Award
Plasmodium spp, P. f and P. v
1
Wet Assay Optimization
Funded: Pending FY10 Award
Flavivirus spp
Various
Wet Assay Optimization
Funded: Pending FY10 Award
Japanese enchephalitis virus
24
Wet Assay Optimization
Funded: Pending FY10 Award
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Value of Pathogen Assays
Relative impact of information availability on risk accuracy, control efficacy, and
on the added value of a pathogen detection assay
Control efficacy
Pathogen assay
(value
added)
Example
Accurate
Effective
Limited
Dengue - Thailand
Accurate
Efffective
NA
Accurate
Partial
NA
Inaccurate
Ineffective
NA
X
Partially
Partial
Significant
X
NA
NA
NA
X
NA
NA
NA
Information Availability
Cases
Vector
Pathogen
Risk accuracy
X
X
X
X
X
X
X
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X
Malaria - Thailand
Dengue – Thailand
Assumptions:
Case data is specific in number and location.
Vector surveillance, pathogen detection tools, and control tools are effective.
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Case data
is valuable!
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Where is the gap?
Adult mosquito/sand fly collection devices minimally effective;
taxonomic keys
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1 or 2 Ae. aegypti /house (15 mins/house); countless man-hours and
houses needed for sufficient sample sizes (1 in 1000 infected); this is an
area where there is transmission of dengue year-round.
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Where is the gap?
BG Sentinel (BG Lure)
Bed net trap - NAMRU-2
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Where is the gap?
Figure 4: Rodent with chiggers
&
Figure 13: Field caught rodent on snap trap
Rodent-baited traps as a tool for collecting chigger mites,
vectors of scrub typhus.
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Other Challenges?
• Low densities; seasonality?
• How does pathogen/vector data translate into risk?
– What does it mean to have 6 in 1000 infected; should I be
concerned?
• Even when we know the vector locations and where the pathogen is
most prevalent in the vector, do we understand the biology?
• Not one-size fits all solutions; same species from different locations
may have evolved independently; different vector ecology
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org
Conclusion
Bottom-line: Pathogen detection has greatest added value for risk
determination and control efficacy in instances where there is limited or
no case data. If disease is seasonal, a valuable forecasting tool.
Challenge: Relevancy of pathogen detection data is highly-dependent on
the vector surveillance tool.
Pathogen surveillance should be a critical part of the PM mission; need
more effective surveillance tools to complement this mission; need
trained soldiers who can interpret information/data.
Where time/resources/money are limited, should be very selective about
when and where to use pathogen detection assays.
Department of Entomology, Armed Forces Research Institute of Medical Sciences
www.afrims.org