environmental surveillance for schistosomiasis
Post on 22-Jan-2018
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Environmental Surveillance for Schistosomiasis
Russell StothardLiverpool School of Tropical Medicine
• Key role of DNA diagnostics
• Interfacing medical malacology
DNA diagnostic platforms – real-time PCR assays with species-probes
• Modern platform for simultaneous detection of pathogens/parasites (semi-automated)
• Assay results in less than 12 hrs, analysis of freshly-collected or ethanol-archive samples
Specimens Stool & urine
water & snails (H) (NH)
Prevalence
&
Intensity
in
PEOPLE
AND(OR)
SNAILS
An environmental framework - transmission biology (contamination v. exposure)
• Conceptual framework
• Applied significance?
Transmission biology – contamination versus exposure
High contamination
Low exposure
Low contamination
High exposure
Egg/antigen detection Increase MDA (x2?)Reduce water contact
Antigen/antibody assaysIncrease WASHSelective PZQ treatment (PSAC?)
MDA & snail control PLUS what?
OR
Sampling framework – challenge of ‘integrated’ specimen collection
egg-patent = ~9%Rt-PCR = ~15%
Church
Towards WHO 2020 Target: Surveillance and Beyond
• Integrate DNA diagnostic platforms BUT this will require increased resourcing
• Need to maintain medical malacology within ‘end-game’ surveillance
• Integrate malacology themes into WASH-related interventions & evaluations
• Develop geographical surveillance systems responsive to focality/seasonality
@DFID_UK@DFID_NTDs
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