Quantitative detection of Plasmodium falciparum DNA in saliva, blood, and urine

Abstract

Background. Current methods for detecting malaria parasites are invasive and associated with poor compliance when repeated sampling is required. New methods to detect and quantify parasites in a less-invasive manner would greatly enhance the potential for longitudinal surveillance in clinical trials. Methods. Saliva, urine, and blood samples from 386 Gambian outpatients with suspected malaria infections were analyzed by nested polymerase chain reaction (nPCR) to detect infection and to evaluate diagnostic accuracy in comparison to expert microscopy. The amount of parasite DNA in malaria-positive samples was estimated using real-time quantitative PCR (qPCR). Results. Blood parasite density as estimated by qPCR correlated well with parasite counts established by microscopy (p = 0.94; P < .001). qPCR results for saliva hada significant correlation with microscopy counts (p = 0.58; P