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

Malaria Journal

Table 3 Titration of P. falciparum in artificial mixed infections by PCR assays targeting ribosomal (18S rRNA) and non-ribosomal (Pvr47/Pfr364) species-specific sequences

Parasite density (per µl of blood)		18S rRNA						Pvr47/Pfr364 (NR targets)
Parasite density (per µl of blood)		Nested-PCR			R-qPCR			NR-cPCR			NR-qPCR
Pv	Pf	#1	#2	#3	#1	#2	#3	#1	#2	#3	#1	#2	#3
1433	1489	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	496	Pv + Pf	Pv + Pf	Pv + Pf	Pv	Pv	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	165	Pv + Pf	Pv + Pf	Pv + Pf	Pv	Pv	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	55	Pv	Pv + Pf	Pv + Pf	Pv	Pv	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	18	Pv + Pf	Pv	Pv + Pf	Pv	Pv	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	6	Pv	Pv	Pv	Pv	Pv	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	2	Pv	Pv	Pv	Pv	Pv	Pv	Pv	Pv	Pv	Pv	Pv + Pf	Pv + Pf
	0.7	Pv	Pv	Pv	Pv	Pv	Pv	Pv + Pf	Pv	Pv	Pv + Pf	Pv + Pf	Pv
PCR positivity		13/24 (54%)^b			2/24 (8%)^a			19/24 (79%)^b,c			22/24 (92%)^c
Target positivity		15/48 (31%)^a′						41/48 (85%)^b′

Artificial mixtures containing P. vivax (Pv) and P. falciparum (Pf) in different proportions were prepared from well-characterized field samples, as described in Methods. The results are expressed as positive to P. vivax and P. falciparum (Pv + Pf), P. vivax (Pv) or P. falciparum (Pf). For each PCR assay, dilution points were assayed in triplicate (#1 to #3)
Different letters (a–c or a^′, b^′) indicate significant differences between proportions (p < 0.05, Fisher’s Exact Test)

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