COMPARISON OF A GENUS-SPECIFIC CONVENTIONAL PCR AND A SPECIES-SPECIFIC NESTED-PCR FOR MALARIA DIAGNOSIS USING FTA COLLECTED SAMPLES FROM KINGDOM OF SAUDI ARABIA.

Abstract

Molecular tools are increasingly accepted as the most sensitive and reliable techniques for malaria diagnosis and epidemiological surveys. Also, collection of finger prick blood spots onto filter papers is the most simple and affordable method for samples preservation and posterior molecular analysis, especially in rural endemic regions where malaria remains a major health problem. Two malaria molecular diagnostic tests, a Plasmodium genus-specific conventional PCR and a Plasmodium species-specific Nested PCR, were evaluated using DNA templates prepared from Whatman-FTA cards' dry blood spots using both, Methanol-fixation/Heat-extraction and FTA commercial purification kit. A total of 121 blood samples were collected from six Saudi south-western endemic districts both, as thick and thin films for routine microscopic screening and onto FTA cards for molecular studies. Out of the 121 samples, 75 were P. falciparum positive by at least one technique. No other species of Plasmodium were detected. P. falciparum parasites were identified in 69/75 (92%) samples by microscopic screening in health care centers. P. genus-specific PCR was able to amplify P. falciparum DNA in 41/75 (55%) and 59/75 (79%) samples using Methanol-fixation/Heat-extraction and FTA purification kit, respectively. P. species-specific Nested PCR revealed 68/75 (91%) and 75/75 (100%) positive samples using DNA templates were isolated by Methanol-fixation/Heat- extraction and FTA purification methods, respectively. The species-specific Nested PCR applied to Whatman-FTA preserved and processed blood samples represents the best alternative to classical microscopy for malaria diagnosis, particularly in epidemiological screening.