Direct Comparison of Standard and Ultrasensitive PCR for the Detection of Plasmodium falciparum from Dried Blood Spots in Bagamoyo, Tanzania

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  • 1 Duke Global Health Institute, Duke University, Durham, North Carolina;
  • 2 Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania;
  • 3 Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina;
  • 4 University of Maryland School of Medicine, Baltimore, Maryland

Ultrasensitive PCR used in low-transmission malaria-endemic settings has revealed a much higher burden of asymptomatic infections than that detected by rapid diagnostic tests (RDTs) or standard PCR, but there is limited evidence as to whether this is the case in higher transmission settings. Using dried blood spots (DBS) collected among 319 schoolchildren in Bagamoyo, Tanzania, we found good correlation (Pearson’s R = 0.995) between Plasmodium falciparum parasite densities detected by a DNA-based 18s rRNA real-time PCR (qPCR) and an RNA-based ultrasensitive RT-PCR (usPCR) for the same target. Whereas prevalence by usPCR was higher than that found by qPCR (37% versus 32%), the proportion of additionally detected low-density infections (median parasite density < 0.050 parasites/µL) represented an incremental increase. It remains unclear to what extent these low-density infections may contribute to the infectious reservoir in different malaria transmission settings.

Author Notes

Address correspondence to Jessica T. Lin, Division of Infectious Diseases, University of North Carolina School of Medicine, 130 Mason Farm Rd., Suite 2115, Chapel Hill, NC 27599. E-mail: jessica_lin@med.unc.edu

Authors’ addresses: Christine F. Markwalter and Tonelia Mowatt, Duke Global Health Institute, Duke University, Durham, NC, E-mails: christine.markwalter@duke.edu and toneliamowatt@gmail.com. Billy Ngasala and Mwajabu Loya, Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, E-mails: bngasala70@yahoo.co.uk and loyamwajabu51@gmail.com. Christopher Basham, Zackary Park, Meredith Muller, and Jessica T. Lin, Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, E-mails: christopher_basham@med.unc.edu, zackarypark@gmail.com, meredith_muller@med.unc.edu, and jessica_lin@med.unc.edu. Christopher Plowe and Myaing Nyunt, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, E-mails: plowe.chris@gmail.com and myaingnyunt@gmail.com.

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