Strategy to improve malaria surveillance system preventing transfusion-transmitted malaria in blood banks using molecular diagnostic

Sérgio Antônio Batista-Dos-Santos,Ândrea Ribeiro-Dos-Santos,Daniel Roberto C Freitas,Ana Cecília Feio,Gleyce F Cabral,Maristela G Cunha,Milene Raiol,Marinete M Póvoa

doi:10.1186/s12936-018-2486-z

Abstract

BackgroundMalaria can be transmitted by blood transfusion through donations collected from asymptomatic or parasitic donors. The parasites are released into the bloodstream during its life cycle and will therefore be present in donated blood by infected individuals. All cases of transfusion-transmitted malaria (TTM) notified since 2005 in Brazil were fatal. A good screening tool for Plasmodium spp. detection in blood units must have a high detection threshold, and the prevention of TTM relies entirely on the exclusion of potentially infected donors. However, in Brazilian blood banks, the screening test relies on blood thick smears examination.MethodsThe molecular diagnostic based on mitochondrial DNA (mtDNA) using real time PCR (mt-qPCR) was improved to detect Plasmodium falciparum, Plasmodium vivax, and standardized for use in Plasmodium malariae. The analytic sensitivity of this mt-qPCR methodology was performed using a sample of P. vivax.ResultsThe mt-qPCR was highly efficient, and the analytic sensitivity for P. vivax was determined (0.000006 parasites/µL). This method was tested to detect P. vivax and P. falciparum in individuals from two malaria-endemic areas in Brazil, Amazon region (Pará and Rondônia states), the samples were collected in 10 reference units of two blood banks (Pará/nine cities and Rondônia/Porto Velho), and parasites mtDNA were detected in 10 of 2224 potential blood donors (0.45%). In all 10 positive samples, only P. vivax was detected.ConclusionMolecular diagnostic using mt-qPCR was effective in revealing infected potential donors with good perspectives to be applied as screening routine of asymptomatic carriers for preventing transfusion-transmitted malaria in blood banks.

Highlights

Malaria can be transmitted by blood transfusion through donations collected from asymptomatic or parasitic donors
In samples collected in the state of Pará, the frequency of malaria parasites in potential donors was analysed according to age and annual parasite index (API), the gender ratio was approximately 4 males to 1 female
Comparison of the mt‐qPCR reactions to detect Plasmodium malariae, Plasmodium falciparum and Plasmodium vivax Initially, mitochondrial qPCR (mt-qPCR) was standardized to detect P. malariae, and the detection threshold was determined in comparison with P. falciparum and P. vivax using this molecular diagnosis

Summary

Introduction

Malaria can be transmitted by blood transfusion through donations collected from asymptomatic or parasitic donors. Haemovigilance is required to identify and prevent the occurrence or recurrence of unwanted transfusionrelated transmissions and to increase the safety, efficacy and efficiency of blood transfusions [8]. This vigilance system should include the monitoring of malaria in endemic areas, such as Africa, South America and some areas in Asia, to detect the five species of the Plasmodium genus that infect humans, Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale and Plasmodium knowlesi [2, 9]

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Conclusion