Platform for malaria diagnosis applied to samples of blood donors from endemic and non-endemic Brazilian areas processed in pool: determination of the frequency of positivity using serological and molecular markers

Abstract

Malaria transmitted by blood transfusion remains one of the infections that are most relevant to hemotherapy services, both in endemic and non endemic areas due to the large increase in the number of individuals moving globally. Data on the frequency of blood transfusion malaria show values ranging from less than 0.2 per million units of blood in non-endemic countries to 50 or more in areas with active transmission. Although the incidence of malaria by blood transfusion is not known in Brazil, this event may contribute to the spread of the disease in situations where the clinical and epidemiological screening in blood banks is not carried out rigorously. Asymptomatic infections with low parasitemias and difficult to detect by conventional haemoscopia represent a challenge for control strategies, both for the natural transmission of the disease, whose programs are based on the detection and treatment of symptomatic cases, as for blood banks, regardless the level of endemicity region. To detect this type of infection is essential to apply more sensitive methods for detection of asymptomatic, with an impact on safer screening of blood donors. Consider also the lack of knowledge about malaria in areas without active transmission. In areas endemic and non-endemic different strategies should be followed transfusion in malaria control. Although some blood banks use the questionnaire to identify risk of malaria transmission, this may allow the collection of infected blood, for lack of information by the candidate for donation. According to the Technical Rules of Procedures haemotherapic, the criteria for screening in endemic areas consider background and level of malaria endemicity. In non-endemic areas, complying with these exclusion criteria, the applicant may be considered able to perform testing of Plasmodium plasmodial antigens or negative in a period between 30 days and 12 months from the offset. Infection by P. malariae is a cause of permanent exclusion, but this species is readily detectable by blood smear. The clinical and epidemiological screening for selection of donors, coupled with testing for specific markers, significantly decreases the possibility of disease transmission through transfusion. This proposal aims to implement a platform for molecular and serological diagnosis in many clinical samples grouped in pools, previously validated in a previous study, which showed comparable sensitivity and specificity to maintain the individual trials, with reduced cost and time. 13 000 samples will be analyzed in the pool, using highly sensitive protocol, capable of detecting a parasite/microliter of blood. The results of this study which will analyze blood samples collected from donors in all Brazilian states may subsidize the decision-making of regulatory hemotherapy agencies. (AU)