Investigating the prevalence of transfusion transmission of Plasmodium within a hyperendemic blood donation system

Background Prevention of transfusion‐transmitted malaria in at‐risk children and pregnant women in endemic areas with inexpensive chloroquine is no longer effective due to widespread drug resistance. There is an urgent need for devising new strategies for transfusion malarial safety. We investigated the frequency of transfusion transmission of malaria within the Ghanaian blood donation system using blood donations from 106 asymptomatic adult Ghanaian blood donors. Study Design and Methods Paired samples from 106 blood donations and recipients (before and after transfusion) were tested for anti‐merozoite surface protein‐1/2 using the commercial Lab21 malaria enzyme immunoassay (EIA), four antigen‐specific in‐house EIAs, and Plasmodium lactate dehydrogenase (pLDH) EIA. Additionally, Plasmodium DNA was screened for using a species‐specific nested polymerase chain reaction (PCR) and a Pan‐Plasmodium quantitative PCR. Donor–recipient parasite identity was defined by two concordant genotyping strategies. Results Plasmodium antibody prevalence was 100% in both donors and recipients, with at least one antigen. Parasitemia prevalence was 54.7% in both donors and recipients with median levels of 20 and 5.3 copies/μL, respectively, the difference being correlated to age (p = 0.0001). Multiple species infections were frequent (8.5%). Twenty‐four units of parasitemic blood were transfused to nonparasitemic recipients, of which 10 (41.7%) became infected after transfusion. Molecular genotyping with 13 distinct markers (antigenic genes and microsatellite loci) identified three to nine parasitemic recipients after transfusion with level of allelic identity suggesting 14% to 28% definite or possible transfusion‐related parasitemia. Conclusion None of the currently available screening assays appear suitable to minimize transfusion malaria without compromising the blood supply in endemic areas.