Risk of transfusion-associated malaria in sub-Saharan Africa: The case of Mali

Introduction: Malaria is a health threat in sub-Saharan Africa, where Plasmodium is not tested in blood bags. Our objective was to determine the prevalence of plasmodial carriage in blood bags and the associated factors, and the involvement of these bags in the occurrence of malaria in recipients.

Methods: From 1st April to 30th November, 2020, we conducted a prospective cross-sectional study of 348 blood bags stored at 4°C in Bamako. Using SPSS 21.0 software, statistical analyses were performed using a binary logistic regression model with a significance threshold of p < 0.05 and the odds ratio (OR) framed by its 95% confidence interval (CI).

Results: During this period, 348 blood bags were transfused into 108/152 hospitalised patients, generating a transfusion frequency of 71.1%, with a prevalence of plasmodial carriage of 22%. Among the 54 initially malaria-negative recipients, all 20 (37%) who received malaria-positive blood bags and slept under long-acting insecticide-treated nets (LLINs) developed malaria. We recorded 33.3% deaths. Donor age ≤ 34 years (p = 0.011; OR = 2.55[CI.95% = 1.25-5.23]), replacement donation (p = 0.000; OR = 0.04[CI.95% = 0.0-0.19]) and not regular use of LLINs by donors (p = 0.048; OR = 0.53[CI.95% = 0.29-1]) were factors associated with plasmodial carriage of blood bags. CD4 count<200 cells/mm³ (p = 0.002; OR = 0.2[CI.95% = 0.10-0.52]), severe anaemia (p = 0.034; OR = 0.26[CI.95% = 0.10-0.90]) and decompensated anaemia (p = 0.034; OR = 3.88[CI.95% = 1.11-13.56]) were factors independently associated with recipient death.

Conclusion: The prevalence of plasmodial carriage among blood donors is increasing in Mali. Transfusion malaria is a reality to be feared, with the risk increasing with the level of malaria endemicity of the blood donor.