Development of a Multiplex Bead Assay to Detect Immunoglobulin G Antibodies to Babesia duncani in Human Serum

Babesia duncani is the causative agent of babesiosis in the western United States. The indirect fluorescent antibody (IFA) assay is the diagnostic test of choice for detection of B. duncani specific antibodies. However, this test requires parasitized red blood cells harvested from infected hamsters and test results are often difficult to interpret. To simplify serological testing for B. duncani , a proteomics approach was employed to identify candidate immunodiagnostic antigens. Several proteins were identified by electrospray ionization (ESI) mass spectrometric analysis and four recombinant protein constructs were expressed and used in a multiplex bead assay (MBA) to detect B. duncani -specific antibodies. Two antigens, AAY83295.1 and AAY83296.1, performed well with high sensitivities and specificities. AAY83295.1 had a higher sensitivity (100%) but lower specificity (89%) in comparison to AAY83296.1, which had a sensitivity of 90% and a specificity of 96%. Combining these two antigens did not improve the performance of the assay. This MBA could be useful for diagnosis, serosurveillance, and blood donor screening for B. duncani infection.

Comparison of a New IgG-EIA for the Detection of Anti-Plasmodium Antibodies with Two Currently Used Assays

<b><i>Background:</i></b> Malaria is a mosquito-borne infectious disease caused by protozoan parasites of the genus <i>Plasmodium.</i> As migration of populations from endemic areas to Europe and overseas recreational travel to endemic regions increase, there is also a growing risk of transfusion-transmitted tropical diseases by blood components. <b><i>Material and Methods:</i></b> In the present study two routine <i>Plasmodium</i> spp. ELISA (CAPTIA™ Malaria EIA, Trinity Biotech, and Malaria EIA, BioRad) were compared with a new commercial ELISA (ELISA IgG, EUROIMMUN). From December 1, 2015 until November 30, 2016, 1,096 plasma samples from blood donors with a potential risk of malaria infection were collected at two blood transfusion centres in Germany and Switzerland. <b><i>Results:</i></b> The samples were tested comparatively with the ELISA from EUROIMMUN and the routine test used at the respective centre. Thirty-four of 595 (5.7%) tested blood samples from centre 1 and 49 of 501 (9.8%) tested blood samples from centre 2 showed reactivity on either or both ELISAs. All 83 reactive samples were sent for confirmation to the Diagnostic Centre of the Swiss Tropical and Public Health Institute (Swiss TPH) in Basel, Switzerland. Sixteen samples, which previously were reactive in the routine <i>Plasmodium</i> spp. EIA assays, were proven positive after confirmation testing (i.e., 4 positive and 12 inconclusive results), indicating an anti-<i>Plasmodium</i> antibody prevalence in blood donations of 1.5%. From these 16 reactive samples, 13 were also detected by the index test, resulting in an assay sensitivity of 81.2%. A specificity of 98.6% was calculated (1,065/1,080 confirmed negative samples). The overall agreement with the reference centre was 95.8% in centre 1 and 94% in centre 2. <b><i>Conclusion:</i></b> The comparison of the new EUROIMMUN ELISA and the established CAPTIA™ Malaria EIA (Trinity Biotech) and Malaria EIA (BioRad) used for routine blood donor screening in two laboratory blood donation centres revealed that all tested ELISAs show comparable sensitivities and are equally suitable for anti-<i>Plasmodium</i> antibody screening in blood banks.

RESPONSE RATE OF DONORS FOR COUNSELING & NOTIFICATION AT UNIVERSITY LEVEL BLOOD CENTER OF NORTH INDIA

Background: Blood transfusion plays a vital role in the management of many diseases but with risk of TTI transmission & many adverse reactions. Blood donor screening and transfusion transmitted infections testing ensures blood safety, so become more stringent all over the world. Aims & objective: The main aim of this study was to assess the response rate of sero-reactive donors. Material and Methods: It was an observational and prospective study done in our department for a period of 13 months during which response rate of TTI reactive donors was analyzed from reactive donor registry. Results: In this study, total 7901 units were screened to TTI screening test. Out of which 130 units (1.6%) were found to be seroreactive. Out of 130 reactive donors, 90 (69.2%) donors were contacted and only 51 (56.6%) donors responded to call & attended counselling and referral to other department for treatment. Conclusion: Universal guidelines, protocols and confidentiality is maintained by every blood center for donor notification. Response rate of reactive donors helps us to frame guidelines to track non responding donors who pose major threat to the healthy donor pool.