(P-BC-76) Surveillance for Babesia in Blood Donors from Manitoba, Canada.

Background/Case Studies: Babesia is a parasite transmitted by the Ixodes tick and has the potential to be transfusion transmitted. Climate change and changing Ixodes tick distributions in Canada posed questions about the impact of Babesia to the blood supply. Following a risk-based decision making (RBDM) process, Canadian Blood Services initiated a multi-year Babesia nucleic acid test (NAT) surveillance program in 2024. The first year of the project focussed on a region (Manitoba, Canada) previously determined by the RBDM analysis to be of highest risk for Babesia NAT-positive donations. The aim of this study is to provide an update on this multi-year surveillance project.

Study

Design/Methods: From 2024-07-11 to 2024-11-09, Roche Whole Blood Collection tubes (RWBCT; Roche Diagnostics GmbH, Mannheim, Germany) were collected from sample diversion pouches at donation sites in Manitoba. Specimens were sent to a research laboratory (Canadian Blood Services Surveillance and Discovery Laboratory, Ottawa, ON). Specimens were frozen until single unit testing with the cobas® Babesia NAT on the Roche cobas® 6800 platform (Roche Diagnostics GmbH, Mannheim, Germany). This NAT can detect multiple species of Babesia without the ability to speciate. Results were stored in an Excel data file (Microsoft, Redmond, WA, USA). Dilution of viscous specimens was done with Basematrix (Basematrix 53, Defibrinated Human Plasma, SeraCare, Milford, MA, USA).



Results/Findings: A total of 14027 whole blood collections were completed in Manitoba with 98.1% (n=13766) sampled for Babesia testing. Testing started 2024-04-08 and by 2024-04-30, 3963 (29%) of available samples were tested. As of 2024-04-30, no Babesia NAT-positive specimens were identified. A total of 3956 specimens were Babesia NAT-negative: 3940 required no additional testing, 13 were initially invalid and required retesting in the RWBCT, and 3 were initially invalid and required retesting after aliquoting into a secondary tube. A total of 7 invalid RWBCT s that failed to resolve after re-testing or pipetting into a secondary tube were observed to be viscous on manual pipetting. These viscous specimens were diluted 1:100, spiked back into RWBCT media and after re-testing were Babesia NAT-negative.

Conclusions: Climate change and changing Ixodes distributions are of concern to Canadian blood operators. However, there is no current data signal suggesting that Babesia is a significant risk to the blood supply. A more formal analysis of risk will be undertaken once the remaining specimens from Manitoba have been analyzed.