Abstract
BackgroundVisceral Leishmaniasis is endemic to Brazil, where it is caused by Leishmania infantum (syn. Leishmania chagasi). Following parasite inoculation, individuals may experience asymptomatic infection, raising the possibility of parasite transmission through the transfusion of contaminated blood products. In the present work, we evaluated the prevalence of asymptomatic Leishmania infection among blood donors in Salvador, northeastern Brazil.MethodsPeripheral blood was collected from 700 blood donors attending the Blood Bank of Bahia (HEMOBA/SESAB), from January to September 2010. We evaluated anti-Leishmania serology by ELISA, employing Soluble Leishmania Antigen (sensitivity 90% and specificity 95%). The presence of parasite DNA was determined by qPCR, targeting a single copy gene (G6PD), and by end-point PCR, targeting multiple targets, namely a segment located in the Leishmania rRNA locus (ITS) and the conserved region of kinetoplastid DNA (kDNA) minicircles.ResultsThe blood-donor population was comprised of 74.5% of males with a mean age of 34 years. Anti-Leishmania serology by ELISA was positive in 5.4% (38/700) individuals. One individual was also positive for Chagas’ disease and another tested positive for Syphilis. Employing qPCR, parasite DNA was not found in any of 38 seropositive samples. However, by ITS PCR, 8/38 (21%) samples were positive and this positivity increased to 26/38 (68%) when we targeted kDNA amplification. Agreement between both techniques (ITS and kDNA PCR) was fair (kappa = 0.219).ConclusionsThese results indicate that asymptomatic infection is present among the blood donor population of Salvador, a finding that warrants a broader discussion regarding the need to implement specific screening strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-422) contains supplementary material, which is available to authorized users.
Highlights
Visceral Leishmaniasis is endemic to Brazil, where it is caused by Leishmania infantum
Transmission of Leishmania parasites occurs through sand fly bites, studies in France {[7] #248}, Italy {[8] #6}, Spain {[9] #12}, India {[10] #9}, Bangladesh {[11] #250} and Turkey {[12] #251} showed that asymptomatic individuals are found among blood donors, suggesting that transfusion of Leishmania-contaminated blood products might be a source of disease transmission in parallel to syringe sharing {[13] #68} and organ transplantation {[14] #7; [15] #8; [16] #19; [17] #41; [18] #246}
Anti-L. infantum serology in blood donors recruited at HEMOBA/SESAB Initially, we determined the sensitivity and specificity of the Soluble Leishmania Antigen (SLA) preparations [obtained from L. infantum or from L. amazonensis] when employed as the capture antigen in Enzyme-linked Immunosorbent Assay (ELISA) assays
Summary
Visceral Leishmaniasis is endemic to Brazil, where it is caused by Leishmania infantum We evaluated the prevalence of asymptomatic Leishmania infection among blood donors in Salvador, northeastern Brazil. Leishmania infantum is the causative agent of VL in Brazil, which accounts for 90% of cases in the Americas {[2] #257} and where 3392 VL cases were reported in 2012 {[3], #258}. In northeastern Brazil, the prevalence of anti-Leishmania antibodies was 9% among blood donors, increased to 25% in a VL focus and was highest (37%) among poly-transfused hemodialysis patients {[19] #37}. In central western Brazil, the prevalence of anti-Leishmania antibodies among a population of blood donors was reported at 15.6% {[21] #262}, indicating the presence of asymptomatic individuals among blood donors in different regions of the country
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