Using blood donor surveillance and clinical case data to shape our understanding of Babesia epidemiology in Manitoba, Canada.

Abstract

BACKGROUND: 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 raised questions about the impact of Babesia on 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 focused 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 that will shape our understanding of Babesia epidemiology in multiple Canadian provinces. STUDY DESIGN AND METHODS: From July 11, 2024 to November 9, 2024, samples were collected in Roche Whole Blood Collection tubes at all whole blood donation sites in Manitoba. Specimens underwent one-time individual testing on the cobas Babesia NAT on the Roche cobas 6800 platform (Roche Diagnostics GmbH, Mannheim, Germany). Clinical cases of babesiosis were reviewed for the period 2013-2025. RESULTS: Of the 13,608 (98%) whole blood donations tested by Babesia NAT, none were positive. Clinical case rates of babesiosis in Manitoba ranged from 0 to 0.13 per 100,000 population annually. DISCUSSION: Changing climate and Ixodes tick distributions have led to concerns that the epidemiology of Babesia infection in Canadian blood donors is increasing. Babesia NAT on specimens from an elevated-risk area for Babesia infection in Canada did not identify Babesia-positive blood donors.