Fig 1.
Plasmodium vivax samples collection sites.
Map of Panama by province showing location of samples collection sites during 2017-2020. Red dots indicate P. vivax samples collection sites where one or more samples were collected. Blue dots indicate healthy control sample collection sites. Inset indicates location of Panama in the American continent. Base map downloaded from www.gadm.org under licence CC-BY. www.gadm.org/maps/PAN_1.html.
Fig 2.
Microscopic detection of Plasmodium vivax asexual and sexual stages.
a) Asexual and sexual stages of selected field samples: 1-2) Rings; 3) Trophozoite; 4-5) Schizonts; 6-9) Gametocytes. Giemsa stain. Black bar = 8 μm. b) Percent parasite stages and parasitemia of selected field samples. N = 61.
Table 1.
qRT-PCR Ct values of two blood volumes of Plasmodium vivax infected blood preserved with RNAprotect and kept at ambient temperature for eight days or snap-freeze at – 80° Celsius.
Fig 3.
Molecular detection of Plasmodium vivax.
a) qRT-PCR Ct values of P. vivax positive field samples for gametocyte markers PvLAP5 and Pvs25 and constitutive marker Pv18SrRNA. N = 63. b) qRT-PCR Ct values of P. vivax negative human control samples for gametocyte markers PvLAP5 and Pvs25 and constitutive marker Pv18SrRNA. N = 16. c) qRT-PCR Ct values of P. vivax malaria naïve lab-bred Aotus monkeys samples for gametocyte markers PvLAP5 and Pvs25 and constitutive marker Pv18SrRNA. N = 15. d) P. vivax gametocyte detection rate plot. Microscopy vs qRT-PCR PvLAP5 and Pvs25 assays. N = 63. e) qRT-PCR standard curve plots of gametocyte markers PvLAP5 and Pvs25 and constitutive marker Pv18SrRNA. f-h) Linear regression plots of gametocyte markers PvLAP5 and Pvs25 and constitutive marker Pv18SrRNA against gametocyte density x μL. N = 63. R2 = coefficient of determination. Dotted lines represent 95% confidence intervals. Ct values ≤ 38 are considered positive.
Table 2.
Summary statistics of Plasmodium vivax grouped by microscopic detection of gametocytes.
Table 3.
Multivariate analysis of Plasmodium vivax field cases.
Table 4.
Summary results of the field performance of a qRT-PCR assay for the detection of Plasmodium vivax gene transcripts in field samples preserved at ambient temperature in RNAprotect compared to microscopy.