Ribosomal and non-ribosomal PCR targets for the detection of low-density and mixed malaria infections

Malaria Journal

Table 2 Titration of P. falciparum single infection by PCR assays targeting ribosomal (18S rRNA) and non-ribosomal (Pfr364) species-specific sequences

P. falciparum monoinfection (13,400 parasites/µL)^c
Parasite density (µL)^d	18S rRNA		Pfr364
Parasite density (µL)^d	Nested-PCR	R-qPCR	NR-cPCR	NR-qPCR
2000	3/3 (100%)	3/3 (100%)	3/3 (100%)	3/3 (100%)
670	3/3 (100%)	3/3 (100%)	3/3 (100%)	3/3 (100%)
220	3/3 (100%)	3/3 (100%)	3/3 (100%)	3/3 (100%)
74	3/3 (100%)	3/3 (100%)	3/3 (100%)	3/3 (100%)
25	2/3 (67%)	2/3 (67%)	3/3 (100%)	3/3 (100%)
8	1/3 (33%)	1/3 (33%)	3/3 (100%)	3/3 (100%)
3	1/3 (33%)	1/3 (33%)	2/3 (67%)	3/3 (100%)
1	0/3 (0%)	0/3 (0%)	1/3 (33%)	0/3 (0%)
0.3	0/3 (0%)	0/3 (0%)	0/3 (0%)	1/3 (33%)
PCR positivity	16/27 (59%)^a	16/27 (59%)^a	21/27 (78%)^a	22/27 (81%)^a
Target positivity	32/54 (59%)^a′		43/54 (80%)^b′

P. falciparum blood-derived DNA template was serial diluted (2000 to 0.3 parasites/µL) and submitted to each PCR protocol in triplicate. The results were expressed as the number of positive samples in relation to the total of replicates (percentage of positive)
Different letters (a, a′, b′) indicate differences between proportions (p < 0.05, Fisher’s Exact Test). PCR assays were defined as described in legend of Fig. 1
^cDetermined by light microscopy
^dParasite density (µL of blood) was estimated according to the fold-dilution

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