Post-transfusion Malaria in Morocco and Non-endemic African Countries: A Systematic Review of Reported Cases.

Abstract

Malaria remains a major global health problem, particularly in Africa. Although transmission is primarily vector-borne, Plasmodium can also be transmitted through blood transfusion, resulting in post-transfusion malaria (PTM). PTM is typically linked to asymptomatic parasitemia in donors and, while uncommon, may be rapidly progressive and potentially fatal. We conducted a systematic review to summarize published PTM cases in African countries considered non-endemic and to identify risk factors and prevention gaps relevant to transfusion services. We searched PubMed/MEDLINE, Google Scholar, and gray literature (including World Health Organization (WHO) documents, national transfusion resources, theses, and conference proceedings) in English and French with no date restrictions; the last search was 30 December 2025. We included case reports, case series, and abstracts with extractable case-level data describing PTM in non-endemic African countries, requiring laboratory confirmation of Plasmodium infection in the recipient and epidemiologic support for transfusion as the most plausible route. Reports suggesting non-transfusion transmission, lacking laboratory confirmation, or providing insufficient evidence implicating transfusion were excluded. Data were extracted using a standardized form, and case-series quality was appraised using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist. Across all sources, 20 PTM cases were identified, but only six were described in sufficient detail for comprehensive extraction. Most detailed cases involved immunocompromised or medically complex recipients. Plasmodium falciparum predominated among fully described cases, consistent with prior reports, although Plasmodium malariae was also documented. Fever occurring days after transfusion was the most common presentation, and diagnosis was typically established by peripheral blood smear. When reported, investigations suggested donor exposure through travel or origin from endemic areas, highlighting the role of asymptomatic carriage and potential gaps in donor risk assessment. Countries without retrievable case-level reports (e.g., Cabo Verde, Lesotho, Seychelles, Egypt, and Libya) may have no accessible published cases, and this does not necessarily mean PTM is absent. PTM remains a rare but clinically important event in non-endemic African countries, with disproportionate risk in vulnerable recipients and potential for diagnostic delay. Strengthening hemovigilance, maintaining clinical suspicion for fever after transfusion, and refining donor risk assessment, potentially including selective testing strategies used in some non-endemic settings, may further reduce residual risk.