Towards a precise test for malaria diagnosis in the Brazilian Amazon: comparison among field microscopy, a rapid diagnostic test, nested PCR, and a computational expert system based on artificial neural networks

Table 4 Identification of symptomatic Plasmodium infection cases according to the parasitaemia.

Parasites/μL	Total	Microscopy				Optimal-IT^®			Nested PCR
		Pf	Pv	Pf+Pv	Negative	Pf	Pnf	Negative	Pf	Pv	Pf+Pv	Negative
Not detected	138	0	0	0	138	0	0	138	0	0	0	138
<100*	32	0	0	0	32	3	10	19	9	23	0	0
100 - 500	47	1	32	0	0	1	32	0	1	32	0	0
		5				5			5
501 - 5,000	24	1	0	5	0	2	2	0	1	0	6	0
		9				2			8
5,001 - 50,000	56	1	40	5	0	1	42	0	1	40	5	0
		1				4			1
>50,000	14	0	12	2	0	2	12	0	0	12	2	0
Total	311	4	84	12	170	5	98	157	5	107	13	138
		5				6			3

Pf = Plasmodium falciparum, Pv = Plasmodium vivax, Pnf = Non-falciparum Plasmodium.
* 32 subjects were negative for Plasmodium infection by field light microscopy. Nevertheless, nested PCR attested positive results (Optimal_IT identified 13 of them). Thus, these individuals probably present very low parasitaemia.

ISSN: 1475-2875