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

Malaria Journal

Table 4 Titration of P. vivax 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
Pf	Pv	#1	#2	#3	#1	#2	#3	#1	#2	#3	#1	#2	#3
1489	1433	Pv + Pf	Pv + Pf	Pv + Pf	Pv	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	478	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	159	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	53	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	18	Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf
	6	Pv + Pf	Pv + Pf	Pv + Pf	Pv + Pf	Pf	Pf	Pv + Pf	Pv + Pf	Pf	Pv + Pf	Pv + Pf	Pv + Pf
	2	Pf	Pf	Pf	Pf	Pf	Pf	Pf	Pf	Pf	Pv + Pf	Pv + Pf	Pv + Pf
	0.7	Pv + Pf	Pf	Pf	Pf	Pf	Pf	Pf	Pf	Pf	Pv + Pf	Pf	Pv + Pf
PCR positivity		18/24 (75%)^a,b			15/24 (63%)^a			17/24 (71%)^a			23/24 (96%)^b
Target positivity		33/48 (69%)^a′						40/48 (83%)^a′

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, b) indicate differences between proportions (p < 0.05, by Fisher’s exact test)
No difference was observed between proportions of targets positivity (a′)

ISSN: 1475-2875