PCR assay in malaria diagnosis using filter paper samples from Jazan region, Saudi Arabia

ABSTRACT

PCR assay using designed primers was evaluated in detecting human malaria infection from whole blood and/or on Whatman filter-paper compared to conventional microscopy. Two DNA extraction methods were used for dried blood-spots; QIAamp mini kit and methanol-fixation/heat-extraction. A total of 118 cases were collected from 4 hospitals at Jazan district. Microscopic examination showed positivity in 66/118 samples [56%]. Thin films showed parasitae-mia from 1+ to 4+. In PCR assay, 79 samples [70%] were positive for the genus Plasmodium given 153 base pair PCR product. All microscopy positive samples were PCR positive but PCR detected 13 cases missed by microscopy. As for filter-paper spot samples, 68 samples [57.6%] were PCR positive when DNA was extracted by QIAamp mini kit whereas 49 [41.5%] by methanol-fixation/heat-extracion method. PCR sensitivity decreased by using DNA extracted from filter-paper compared to microscopy and whole blood PCR. But the DNA isolated from filter paper detected parasites in many microscopy negative samples