Leishmania detection in sand flies using a field-deployable real-time analytic system.

We describe here the development and evaluation of advanced vector surveillance analytic technologies for real-time leishmaniasis risk assessment. Leishmania genus and visceral leishmaniasis causative agent--specific dual fluorogenic-probe hydrolysis (TaqMan), thermally stable (freeze-dried) polymerase chain reaction assays were developed using field-durable analytic instrumentation. In laboratory testing with a panel of diverse Leishmania species from culture and infected sand flies, the sensitivity and specificity of both assays were 100% concordant with DNA sequencing. In specificity testing with Leishmania genetic near neighbors, clinically significant organisms, and human genomic DNA, no detectable fluorescence above background was observed. Field evaluation was conducted in southern Iraq using wild sand flies. In field testing, Leishmania genus assay was 100% sensitive and 96% specific with a single false-positive result. The visceral leishmaniasis genotype assay was 100% sensitive and 100% specific compared to DNA sequencing. Thermally stable polymerase chain reaction assays vastly simplified transportation and storage. Assay preparation and analysis required less than 2 hours.