Transfusion-transmitted Plasmodium spp. infections and safety challenges for malaria in the Indian subcontinent: a systematic review

Blood transfusion is a globally life-saving intervention, but blood-borne pathogens can threaten its effectiveness. While blood bags are systematically screened for viral and bacterial pathogens, parasite infections are generally overlooked. In this review, we analysed the current literature on transfusion-transmitted malaria (TTM) in India over the past five decades. This analysis is based on 122 studies involving more than 6.5 million individuals. The prevalence of Plasmodium parasitaemia in donors ranged from ∼0% to 0.87% by light microscopy and ∼0% to 2.3% by rapid diagnostic tests. The proportion of post-transfusion malaria (PTM) cases ranged from 0.8% to 6.8% across the studies. The risk of PTM is both time- and diagnosis method-dependent and relatively high in some regions of India. The clinical impacts of PTM range from mild to severe and even fatal outcomes. It is also crucial to address TTM given the often-neglected Plasmodium malariae, in addition to the prevalence of Plasmodium vivax and Plasmodium falciparum. The spread of drug-resistant and/or pfhrp2 gene-deleted P. falciparum parasites is another threat in PTM. Blood screening could be achieved through point-of-care nucleic acid amplification techniques to guarantee safer transfusion. If neglected, TTM can become an obstacle to malaria elimination in the coming years.