Malaria infection diagnosis: comparison between traditional methods and a new freeze-dried PCR multiplex test

Abstract

Malaria is the most diffused parasitic disease that affects humans.A rapid and accurate diagnosis is a prerequisite for an effective treatment. The development of a new ready-to-use test for the screening and the typing of malaria solve the temperature storage requests of common molecular tests and PCR reagents. The performances of STAT-NAT Malaria Screening and STAT-NAT Malaria Typing kits were tested on samples obtained from patients suspected to be infected by malaria’s parasites, Immigrants (I) and International Travellers (IT), and were compared with the gold standard method (microscopy). Samples of peripheral blood of 35 patients (25 IT and 10 I) obtained from San Matteo Hospital in Pavia were analysed.The microscopy identified 18 of them as positive samples: 11 samples were positive for Plasmodium falciparum (5 IT, 6 I), 3 for Plasmodium vivax (3 IT), 2 for Plasmodium ovale (1I, 1 IT) and 2 for Plasmodium malariae (2 I). No co-infections were found. STAT-NAT Malaria kits confirmed the results of 18 positive samples as well as of 17 negative samples (100% sensitivity). In a case STAT-NAT Malaria Typing kit identified the presence of Plasmodium ovale in a sample instead of Plasmodium vivax, as previously diagnosed with the microscopic analysis.The epidemiological analysis and a new microscopic diagnosis confirmed the infection as caused by Plasmodium ovale species (100% specificity). We conclude that the association of the freeze-dried STAT-NAT Malaria tests could be determinant for the correct detection and typing of malaria, mainly where the temperature controlled storage could be problematic.

Keywords

• Malaria, Plasmodium, early diagnosis, PCR, Freeze drying