Figure 1.
Flow diagram of molecular analyses performed for detection of asexual and sexual parasite stages of P. vivax and P. falciparum in field samples from PNG.
Red and blue frames indicate assays done on DNA and on RNA, respectively. Orange and green boxes are P. falciparum and P. vivax-specific assays, respectively. P. malariae and P. ovale assays are not included in the diagram.
Figure 2.
DNA- versus RNA-based quantification of Plasmodium parasites by qPCR and qRT-PCR of 18S rRNA genes or transcripts in comparison to light microscopy (LM).
P. falciparum (upper panel) and P. vivax (lower panel). Boxed values indicate the correlation coefficient (r2) and the conversion functions extracted from these data. All correlation coefficients (r2) were significant (p-value < 0.001).
Figure 3.
Comparison of two blood sampling strategies for measuring gametocyte prevalence rates.
(A) P. falciparum, (B) P. vivax. Gametocyte positivity (left panel) and transcript copy numbers (right panel) are shown for RNAprotect solution versus filter paper soaked in TRIzol. Only samples were compared for which both measurements were available.
Figure 4.
Gametocyte trend line generated with 3D7 P. falciparum in vitro culture for converting pfs25 transcript copy numbers into gametocyte counts.
Dashed lines indicate 95% confidence interval of intercept.
Figure 5.
Effect of extended storage time on pfs25 transcripts.
20 samples were chosen to represent a wide range of transcript copy numbers at start of the 2 yr storage period. The initial copy numbers (black bars) are shown next to copy number detected 2 yrs later in the same RNA sample (white bars).