Transfusion-transmitted Malaria Research Articles

Detection of Plasmodium spp. in asymptomatic blood donors by the new Brazilian NAT PLUS HIV/HBV/HCV/Malaria Bio-Manguinhos kit.

Transfusion-transmitted malaria (TTM) is a public health problem in endemic and nonendemic areas. The Brazilian Ministry of Health (MH) requested the development of a nucleic acid amplification test (NAT) for the detection of Plasmodium spp. in public blood centers to increase blood safety. The new Brazilian NAT kit named NAT PLUS HIV/HBV/HCV/Malaria Bio-Manguinhos was first implemented in HEMORIO, a public blood center in the city of Rio de Janeiro. Since October 1, 2022, this blood center has been testing all its blood donations for malaria in a pool of six plasma samples to detect Plasmodium spp. by real-time polymerase chain reaction (PCR). Since the implementation of the NAT PLUS platform until February 2023, HEMORIO has successfully received and tested 200,277 donations. The platform detected two asymptomatic donors in the city of Rio de Janeiro, which is a nonendemic region for malaria. Our analyses suggested a malaria from the Amazon region caused by Plasmodium vivax, in the first case, while an autochthonous transmission case by Plasmodium malariae was identified in the rural area of Rio de Janeiro state. The NAT PLUS platform detects Plasmodium spp. in plasma samples with sensitivity capable of detecting subpatent infections. This is the first time worldwide that a group developed and implemented molecular diagnosis for Plasmodium spp. to be used by public blood centers to avoid TTM.

A novel mitigation strategy for the prevention of transfusion-transmitted malaria.

Malaria is caused by protozoa of the genus Plasmodium and transmitted by Anopheles mosquitos. In the US, blood donors are assessed for malaria risk, including donor travel or previous residence in endemic areas and history of malaria by questionnaire and deferred for three months or three years, respectively. The Procleix Plasmodium Assay is a qualitative nucleic acid test based on transcription-mediated amplification (TMA) for the detection of 18S ribosomal RNA of P. falciparum, P. ovale, P. vivax, P. malariae, and P. knowlesi for use on the Procleix Panther system. Analytical sensitivity was evaluated with in vitro transcripts and infected red blood cells. For clinical specificity, 12,800 individual donations and 283 pools of 16 samples from routine US donors were screened. Malaria risk was evaluated by testing 862 donors deferred for 3 years. Reactive results were confirmed with in-house real-time TMA assay and serology. Assay sensitivity was 8.47-11.89 RNA copies/mL and 2.10-6.82 infected red cells/mL. Specificity was 99.99% in 12,800 individual donations and 100% in 283 pools of 16. Of 862 tested deferred donor samples, one donor (0.12%) confirmed positive individually and in pools; he remained confirmed positive for 13 months. The infected donor was a prior resident of a malaria-endemic area in West Africa. The Procleix Plasmodium Assay showed high sensitivity and specificity and detected Plasmodium RNA in an asymptomatic presenting donor. This assay may prove helpful as a screening test versus the use of risk questions to reduce the number of donors deferred for malaria risk.

Survey in Iranian Malaria Blood Donation Deferral: Laboratory Evaluation in Malaria Blood Donation Deferral in the Iranian Blood Centers

Introduction: Transfusion-transmitted malaria (TTM), from a malaria infected donor, is an accidental Plasmodium infection, which is one of the concerns of blood transfusion issue in the world. Countries have adopted different strategies for donor selection and improving criteria to overcome these concerns, In the Iranian Blood Transfusion Organization (IBTO), donors who refer to blood transfusion centers after registration are screened by the physicians based on interview and examination. This prevention due to the possibility of malaria infection is called malaria donor deferral strategy.
 Methods: In this study 248 malaria blood donation deferral samples were selected and evaluated by microscopic, serological and molecular methods, after completing the questionnaire.
 Results: The results of the survey of the questionnaires showed that 30 cases were deferred from donating blood due to having a history of malaria infection. In microscopic examination, Plasmodium ring was observed in 2 samples and 2 samples were also reported as suspicious. In serological examination, 23 cases (9.27%) were reported positive. All cases were reported negative for the presence of malaria parasite DNA.
 Conclusions: The adoption of TTM prevention strategies depends on the malaria endemicity of the geographical area. According to the IBTO instructions, donors are examined and interviewed by a blood transfusion physician’s and owning to traveling or residency in endemic area or malaria infection, deferred temporary or permanently.
 Recent study reveal that the strategy of donor selection and deferral in the IBTO, with little residual risk of malaria transmitting, is sufficient to prevent the occurrence of TTM in Iran.

Rapid Visual Detection of Plasmodium Using Recombinase-Aided Amplification With Lateral Flow Dipstick Assay.

BackgroundMalaria is a global public health problem. China has had no case of indigenous malaria since 2016. However, imported cases of malaria remain an issue among travelers, overseas workers, and foreign traders. Although these cases are always asymptomatic, if they donate blood, there is a great risk of transfusion transmitted-malaria (TTM). Therefore, blood banks need a rapid screening tool to detect Plasmodium species.MethodsWe designed an assay using recombinase-aided amplification (RAA) and a lateral-flow dipstick (LFD) (RAA-LFD) to detect the 18S ribosomal RNA gene of Plasmodium species. Sensitivity was evaluated using a recombinant plasmid and Plasmodium genomic DNA. Specificity was evaluated using DNA extracted from the blood of patients with malaria or other infectious parasites. For clinical assessment, blood samples from patients with malaria and blood donors were evaluated.ResultsThe RAA-LFD assay was performed in an incubator block at 37°C for 15 min, and the amplicons were visible to the naked eye on the flow dipsticks within 3 min. The sensitivity was 1 copy/μL of recombinant plasmid. For genomic DNA from whole blood of malaria patients infected with P. falciparum, P. vivax, P. ovale, and P. malariae, the sensitivity was 0.1 pg/μL, 10 pg/μL, 10-100 pg/μL, and 100pg/μL, respectively. The sensitivity of this assay was 100pg/μL. No cross-reaction with other transfusion-transmissible parasites was detected.ConclusionsThe results demonstrated that this RAA-LFD assay was suitable for reliable field detection of Plasmodium species in low-resource settings with limited laboratory capabilities.

Robust inactivation of Plasmodium falciparum in red blood cell concentrates using amustaline and glutathione pathogen reduction

Background Plasmodium falciparum is the parasite responsible for most malaria cases globally. The risk of transfusion‐transmitted malaria (TTM) is mitigated by donor deferrals and blood screening strategies, which adversely impact blood availability. Previous studies showed robust inactivation of P. falciparum using nucleic acid‐targeting pathogen reduction technologies (PRT) for the treatment of plasma and platelet components or whole blood (WB). The efficacy of the amustaline–glutathione (GSH) PRT to inactivate P. falciparum is here evaluated in red blood cells (RBC), as well the impact of PRT on parasite loads, stages, and strains.Study Design and MethodsRBC units resuspended in AS‐1 or AS‐5 additive solutions were spiked with ring stage‐infected RBC and treated with the amustaline–GSH PRT. Parasite loads and viability were measured in samples at the time of contamination, and after treatment, using serial 10‐fold dilutions of the samples in RBC cultures maintained for up to 4 weeks.Results P. falciparum viability assays allow for the detection of very low levels of parasite. Initial parasite titer was >5.2 log10/ml in AS‐1/5 RBC. No infectious parasites were detected in amustaline–GSH‐treated samples after 4 weeks of culture. Amustaline–GSH inactivated high parasite loads regardless of parasite stages and strains. Amustaline readily penetrates the parasite, irreversibly blocks development, and leads to parasite death and expulsion from RBC.DiscussionAmustaline–GSH PRT demonstrated robust efficacy to inactivate malaria parasites in RBC concentrates. This study completes the portfolio of studies demonstrating the efficacy of nucleic acid‐targeting PRTs to mitigate TTM risks as previously reported for platelet concentrates, plasma, and WB.

Immunochromatographic and microscopic detection of Plasmodium falciparum in recipients of P. falciparum-infected donor blood.

Blood transfusion practice is an essential medical intervention; however, it poses problems of transmissibility of infectious diseases including malaria. This study was designed to determine the potential of transfusion-transmitted malaria (TTM) by detecting malaria antigens and parasites in recipients of infected donor blood. After successful blood transfusion, remnants of transfused blood were screened for Plasmodium falciparum HRP2 antigen and parasitemia using CareStart malaria RDT and 10% Giemsa stain microscopy respectively according to established protocols. Recipients of microscopy detectable P. falciparum in infected blood who tested negative for malaria by both microscopy and mRDT prior to receiving infected donor blood were followed up weekly for 35 days. Donor P. falciparum antigenemia and parasitemia were 12.1% and 8.4%, respectively, while the prevalence of blood recipient parasitemia was 3.2%. Blood stored for 2–5 days recorded mean parasitemia higher than those stored for a day and after 5 days. Additionally, parasitemia was observed in all follow-up days with marginally high frequencies in days 7, 14, and 35. There was no association between the attributes (storage days, blood group, and parasite count range) of the infected donor blood units and the characteristics of blood recipients with post-transfusion parasitemia. This study provides baseline data on TTM in Ghana. However, further studies should establish the genetic relatedness of the implicated parasites since new infections and/or recrudescence of previous infections could account for this observation.

Transfusion-Transmitted Malaria of Plasmodium malariae in Palermo, Sicily

Transfusion-transmitted malaria (TTM) is a rare occurrence with serious consequences for the recipient. In non-endemic areas, the incidence of transmission of malaria by transfusion is very low. We report a clinical case of transfusion-transmitted malaria due to Plasmodium malariae, which happened in a patient with acute hemorrhagic gastropathy. Case presentation: In April 2019, a 70-year-old Italian man with recurrent spiking fever for four days was diagnosed with a P. malariae infection, as confirmed using microscopy and real-time PCR. The patient had never been abroad, but about two months before, he had received a red blood cell transfusion for anemia. Regarding the donor, we revealed that they were a missionary priest who often went to tropical regions. Plasmodium spp. PCR was also used on donor blood to confirm the causal link. Discussion and Conclusions: The donations of asymptomatic blood donors who are predominantly “semi-immune” with very low parasitic loads are an issue. The main problem is related to transfusion-transmitted malaria. Our case suggests that P. malariae infections in semi-immune asymptomatic donors are a threat to transfusion safety. Currently, microscopy is considered the gold standard for the diagnosis of malaria but has limited sensitivity to detect low levels of parasitemia. Screening using serological tests and molecular tests, combined with the donor’s questionnaire, should be used to reduce the cases of TTM.

Evaluating laboratory screening tests for malaria on blood donors candidates to reduce the risk of transfusion-transmitted malaria in an endemic area of Indonesia

BACKGROUND Laboratory screening of blood donors for malaria has not been routinely performed in Indonesia. Current policy and practice simply exclude donors based on a history of active clinical malaria. This study was aimed to evaluate laboratory screening tests for malaria among blood donors in an endemic area of Indonesia.
 METHODS The study was conducted on 550 consecutive blood samples withdrawn from volunteer donors at the Red Cross Blood Transfusion Unit in Ambon city using microscopic and rapid diagnostic tests for antigen as well as for antibody. Furthermore, 248 of those 550 samples were also tested for the presence of malaria DNA using 18S rRNA marker. Statistical analysis was done descriptively using SPSS software version 15 (SPSS Inc., USA).
 RESULTS The overall malaria positivity rate among the donors was 4.5% (25/550). None of the specimens tested using microscopy or rapid test for malaria antigen assay were positive. However 22 (4.0%) samples were positive for malaria antibody against Plasmodium falciparum; while 3 (1.2%) were positive by PCR.
 CONCLUSIONS Laboratory testing for blood donors may be used to prevent transfusiontransmitted malaria in an endemic area of Indonesia.

Transfusion-Transmitted Malaria: Two Pediatric Cases From the United States and Their Relevance in an Increasingly Globalized World.

In non-endemic settings, transfusion-transmitted malaria (TTM) is rare but potentially fatal and becoming more common with globalization. We present two pediatric cases that demonstrate donor screening using questionnaires is subject to error and that TTM should be considered with fever following numerous transfusions in children, particularly sickle cell patients.

Evaluation of the Sysmex XN-31 automated analyser for blood donor malaria screening at Malawi Blood Transfusion Services.

Background and ObjectivesBalancing blood supply safety and sufficiency is challenging in malaria‐endemic countries where the risk of transfusion‐transmitted malaria (TTM) is ever‐present. In support of reducing this risk, our study aimed at evaluating the performance of the Sysmex XN‐31 analyser in blood donor malaria screening, as compared with current practice in Malawi.Materials and MethodsThis prospective observational study was conducted on remnant venous donor blood samples collected at Malawi Blood Transfusion Service donation sites countrywide for routine blood‐borne pathogen screening. XN‐31 results were compared with routine thick smear malaria microscopy, using expert microscopy (phase 1 and 2) plus qualitative malaria polymerase chain reaction (PCR) (phase 2) to adjudicate discrepancies.ResultsXN‐31 detected malaria in 614 (11.6%) of 5281 study samples compared with 341 (6.5%) for routine microscopy. Of the 273 discrepant samples, 60 smears (phase 1) could not be retrieved for expert microscopic review. Expert microscopy confirmed the XN‐31 positivity in 78.8% (149/189) and 91.7% (22/24) of discrepant samples in phase 1 (n = 4416) and phase 2 (n = 975), respectively, with two cases requiring PCR testing, confirming one each as positive and negative, giving sensitivities of 100% and 75% and specificities of 99.9% and 100%, respectively, for XN‐31 and routine microscopy.ConclusionThe automated Sysmex XN‐31 analyser's high sensitivity and specificity, ability to detect all Plasmodium species and high throughput with rapid turnaround‐time, overcomes many of the limitations of currently available diagnostic tests, making it well‐suited for malaria screening of donated blood in malaria‐endemic countries in support of TTM risk reduction.

Malaria Transfusional Transmission: Epidemiological Review, Screening Protocols and Prevention Mechanisms

Malaria is a neglected tropical disease, whose main form of transmission occurs through the bite of the female Anopheles mosquito infected by the parasite Plasmodium sp. Its clinical symptoms range from asymptomatic cases to more severe and fatal conditions. Added to this natural transmission mechanism, many studies report that Malaria is one of the main infectious diseases transmitted by transfusion. There are reports of prevalence among blood donors in the five continents, with the highest number of cases in Africa, Asia and South America, regions of high endemicity. Factors such as the high prevalence rate of asymptomatic malaria carriers, as well as deficient regulation in the screening of blood donors and an ineffective hemovigilance policy make the risk of Transfusion-Transmitted Malaria (TTM) worse, exposing millions of people possible contamination by transfusion, especially in underdeveloped countries. Patients with underlying diseases or immunosuppressed who require polytransfusions are the most susceptible to TTM. After an eventual transfusion of bags contaminated by Plasmodium sp, these patients can develop the most severe form of the disease, presenting high-risk clinical complications that can culminate in fatal outcomes. In view of the facts and aiming at greater transfusion safety, it is observed that stricter regulatory policies aimed at preventing TTM are needed; such policies will be more comprehensive if coordinated by the World Health Organization (WHO) and more effective if they are adequate to the reality of endemic and non-endemic countries. In blood banks, control measures should focus mainly on broad serological coverage with high performance tests, in addition to active hemovigilance programs and encouragement of research and implementation of methods of inactivation of pathogens in blood component bags. Given the above, this study was carried out with the aim of providing knowledge of the current panorama of the prevalence of malaria among blood donors and of documented cases of TTM around the world, as well as demonstrating the disease tracking methodologies in use in different countries, and present possibilities for adopting mechanisms that allow better control of the transfusional transmission of malaria in blood banks.

Current Situation of Transfusion-Transmitted Malaria in China.

Although China is moving toward the eradication of malaria and no indigenous malaria has been reported in most Chinese provinces for several years, recent evaluations have revealed that imported cases remain a major challenge to eliminating malaria, with the number of transfusion-transmitted malaria (TTM) cases increasing over time. Here, we review several TTM case reports published after the implementation of the National Malaria Elimination Program in 2010. A total of 12 TTM cases were reported in China between 2013 and 2018. All recipients and donors were diagnosed using rapid diagnosis test and peripheral blood smears. Plasmodium species in donors with low-density parasites were identified using PCR. Nine (75.0%) were identified as Plasmodium falciparum, two (16.7%) were identified as Plasmodium vivax, and one (8.3%) was identified as Plasmodium ovale. All were imported from malaria-endemic areas. New action plans designed to meet the challenges of TTM are necessary to ensure the elimination of malaria in China. Paying more attention to the frequency of TTM could help to enhance blood safety in China.

Haemoglobin phenotypes and the risk of asymptomatic malaria parasitemia among blood donors in northwest Nigeria: clinical implications in the practice of tropical transfusion medicine

Background: In malaria-endemic populations, sickle cell trait (SCT) protects against both severe and non-severe malaria, but inconsistencies exist about protective effect of SCT on asymptomatic malarial parasitemia (AMP). Surprisingly, the effect of Hb-phenotypes on AMP has not been explored among blood donors in Nigeria or other malaria-endemic countries, where risks of AMP and transfusion transmitted malaria (TTM) are high. The objective of this study is to determine risk of AMP with respect to donor Hb-phenotypes (SCT versus HbAA), and elucidate clinical implications of AMP with respect to risk of TTM vis-à-vis the practice of transfusion medicine in Nigeria, and by implication other malaria-endemic tropical countries.Methodology: Analysis of 100 blood donors with AMP (cases) and 100 donors without AMP (controls) was performed. Frequencies of SCT and HbAA (determined by Hb electrophoresis) among cases and controls were compared by X2 -test. Risks of AMP (detected by microscopy) with respect to Hb-phenotypes were expressed as Odds ratios (OR) by case-control logistic regression.Results: In comparison with blood donor without AMP (controls), donors with AMP had lower frequencies of SCT (12% vs 28%, p<0.05) with corresponding higher frequencies of HbAA (88% vs 72%, p<0.05). HbAA is associated with high risk of AMP (OR=2.91, 95%CI: 2.10-3.48, p=0.021), while SCT is associated low risk of AMP (OR=0.49, 95%CI: 0.27-0.73, p=0.032).Conclusion: This finding shows that donor SCT is a surreptitious mitigator of the risk of AMP and TTM in the tropics. Therefore, patients who are selectively transfused with HbAA blood (e. g. neonates and sickle cell disease patients) could be at greater risks of TTM, and such patients need closer post transfusion monitoring. The risk of TTM calls for diligent post transfusion haemovigilance in Nigeria and other malaria endemic tropical countries in Africa
 Keywords: blood donors, sickle cell trait, asymptomatic malaria parasitemia, transfusion transmitted malaria

Preventing transfusion-transmitted malaria in France.

Preventing transfusion-transmitted malaria in France.

Malaria Seroprevalence in the Blood Donors of Malaria Endemic Regions of Northern Andhra Pradesh, India.

Introduction: Transmission of malaria through blood transfusion continues to be a major threat tosafe blood transfusion practice. Transfusion-transmitted malaria occurs at an estimated rate of 0.25cases per 1 million blood units collected. It is significantly more common in endemic areas. Aim: Tostudy the Seroprevalence of Malaria among the blood donors in the endemic areas of NorthernAndhra Pradesh. Materials and methods: The present survey was carried out at the blood bank ofMaharaja institute of medical sciences, Vizianagaram. This includes the analysis of seroprevalence ofMalaria in the blood donors during the period of 1 year from February 2018 to January 2019. Two mlof the blood sample was collected in the labeled pilot tube at the time of collection of blood fromdonor tubing of the blood bag. The serum was separated. The samples were tested for Malaria byrapid antigen detection test. Results: Out of the total of 3096 blood donors, replacement donors(86.91%) were more in comparison to voluntary donors (13.08%). The seroprevalence among thereplacement blood donors was more compared to voluntary blood donors. Conclusion: Voluntaryblood donation, increasing awareness about blood donation in the general population, selection ofrepeat, non-remunerated, regular voluntary blood donors and diligent donor selection, sensitivescreening tests are most important to increase blood safety and prevent transmission of Malariathrough blood transfusion.

Characterization of putative drug resistant markers in Plasmodium falciparum isolated in Ghanaian blood donors

Background: Plasmodium falciparum parasites are commonly detected in blood donors in malaria-endemic areas. Even though few cases of transfusion-transmitted malaria have been reported, this study sought to establish the relative proportions of putative anti-malaria drug biomarkers in Ghanaian blood donors. Methods & Materials: Blood donors were randomly selected from five districts in Greater Accra region, Ghana. Each donor sample was screened with SD Bioline rapid diagnostic test kit (RDT). Dry blood spots were prepared from positive samples and shipped to Malaria Genome Laboratory, Wellcome Sanger Institute, Hinxton-UK for sequencing by genotyping of Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Kelch 13 genes. Results: A total of 771 blood donors were sampled out of which 91 (11.8%) were confirmed infected by RDT. Analysis of sequence reads indicated successful genotyping of Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Kelch 13 genes in 67 (73.6%), 64 (70.3%), 69 (75.8%), 69 (75.8%) and 84 (92.3%) of the genotyped isolates respectively. Of the total isolates, 191 different mutant haplotypes and single nucleotide polymorphisms were identified. In Pfcrt, CVIET haplotype was observed in 9 (13.4%) samples. In Pfmdr1, NFD, NYY, YFN and NFY haplotypes were identified in 4 (6.3%), 4 (6.3%), 6 (9.4%) and 8 (12.5%) samples respectively. In Pfdhfr gene single [NRSI, n = 17 (24.6%); NCNI, n = 20 (28.9%)], double [IRNI, n = 13 (18.8%); NRNI, n = 6 (8.6%)] and triple [IRNI, n = 6 (8.6%)] mutations were observed while in Pfdhps gene, the following haplotypes were seen: SGKAA (n = 19, 27.5%), AGKAA (n = 17, 24.6%), AGKAS (n = 13, 18.8%), AGKSA (n = 9, 13.0%), FGKAS (n = 5, 7.2%), AGKSS (n = 5, 7.2%) and AGESS (n = 1, 1.4%). Finally, in Kelch 13 gene, four non-synonymous mutations were identified in 11 isolates; P615L (n = 4, 4.8%), A578S (n = 4, 4.8%), I543 V (n = 2, 2.4%) and A676S (n = 1, 1.2%). Conclusion: The results obtained in this study indicated up to 28.9% risk of being transmitted with anti-malaria drug resistant gene during transfusion of P. falciparum infected blood. However, not higher than 12.5% putative drug resistant biomarkers could reduce efficacy of artemisinin combination therapy.

Use of a NAT-based assay to improve the surveillance system and prevent transfusion-transmitted malaria in blood banks

BackgroundMalaria can be transmitted by blood transfusion through donations collected from asymptomatic donors. Transfusion-transmitted malaria (TTM) poses a great risk to blood services worldwide. A good screening tool for Plasmodium spp. detection in blood banks must have a high sensitivity for prevention of TTM. However, in Brazilian blood banks, screening for malaria still relies on microscopy.MethodsIn Brazil, screening for human immunodeficiency virus type 1 (HIV), RNA/DNA for hepatitis C (HCV) and hepatitis B (HBV) viruses is mandatory for every blood donation and uses nucleic acid amplification testing (NAT). The aim of this study was to evaluate the inclusion of an assay for malaria to identify Plasmodium sp. from total nucleic acid (TNA; DNA/RNA) by targeting the 18S rRNA gene of the parasite.ResultsConsidering the limitations of microscopy and the wide availability of the Brazilian NAT platform in the screening of blood units for HIV, HCV, and HBV, a molecular diagnostic tool was validated for detection of Plasmodium sp. in blood banks; a pilot study showed that using this novel NAT assay could reduce the risk of TTM.ConclusionThe prototype HIV/HCV/HBV/malaria NAT assay was effective in detecting infected candidate donors and has good prospects to be applied in routine screening for preventing TTM.

Characterization of putative drug resistant biomarkers in Plasmodium falciparum isolated from Ghanaian blood donors

BackgroundPlasmodium falciparum parasites, which could harbour anti-malaria drug resistance genes, are commonly detected in blood donors in malaria-endemic areas. Notwithstanding, anti-malaria drug resistant biomarkers have not been characterized in blood donors with asymptomatic P. falciparum infection.MethodsA total of 771 blood donors were selected from five districts in the Greater Accra Region, Ghana. Each donor sample was screened with malaria rapid diagnostic test (RDT) kit and parasitaemia quantified microscopically. Dried blood spots from malaria positive samples were genotyped for P. falciparum chloroquine resistance transporter (Pfcrt), P. falciparum multi-drug resistance (Pfmdr1), P. falciparum dihydropteroate-synthetase (Pfdhps), P. falciparum dihydrofolate-reductase (Pfdhfr) and Kelch 13 propeller domain on chromosome 13 (Kelch 13) genes.ResultsOf the 771 blood donors, 91 (11.8%) were positive by RDT. Analysis of sequence reads indicated successful genotyping of Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Kelch 13 genes in 84.6, 81.3, 86.8, 86.9 and 92.3% of the isolates respectively. Overall, 21 different mutant haplotypes were identified in 69 isolates (75.8%). In Pfcrt, CVIET haplotype was observed in 11.6% samples while in Pfmdr1, triple mutation (resulting in YFN haplotype) was detected in 8.1% of isolates. In Pfdhfr gene, triple mutation resulting in IRNI haplotype and in Pfdhps gene, quintuple mutation resulting in AGESS haplotype was identified in 17.7% parasite isolates. Finally, five non-synonymous Kelch 13 alleles were detected; C580Y (3.6%), P615L (4.8%), A578S (4.8%), I543V (2.4%) and A676S (1.2%) were detected.ConclusionResults obtained in this study indicated various frequencies of mutant alleles in Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Kelch 13 genes from P. falciparum infected blood donors. These alleles could reduce the efficacy of standard malaria treatment in transfusion-transmitted malaria cases. Incorporating malaria screening into donor screening protocol to defer infected donors is therefore recommended.

Malaria parasitemia among blood donors in Uganda.

Malaria remains a leading transfusion associated infectious risk in endemic areas. However, the prevalence of malaria parasitemia has not been well characterized in blood donor populations. This study sought to determine the prevalence of Plasmodium in red blood cell (RBC) and whole blood (WB) units after the rainy season in Uganda. Between May and July 2018, blood was collected from the sample diversion pouch of 1000 WB donors in Kampala and Jinja, Uganda. The RBC pellet from ethylenediamine tetraacetic acid (EDTA) anticoagulated blood was stored at -80°C until testing. DNA was extracted and nested PCR was used to screen samples at the genus level for Plasmodium, with positive samples further tested for species identification. Malaria parasitemia among asymptomatic, eligible blood donors in two regions of Uganda was 15.4%; 87.7% (135/154) of infections were with P. falciparum, while P. malariae and P. ovale were also detected. There were 4.3% of blood donors who had mixed infection with multiple species. Older donors (>30 years vs. 17-19 years; aPR = 0.31 [95% CI = 0.17-0.58]), females (aPR = 0.60 [95% CI = 0.42-0.87]), repeat donors (aPR = 0.44 [95% CI = 0.27-0.72]) and those donating near the capital city of Kampala versus rural Jinja region (aPR = 0.49 [95% CI = 0.34-0.69]) had a lower prevalence of malaria parasitemia. A high proportion of asymptomatic blood donors residing in a malaria endemic region demonstrate evidence of parasitemia at time of donation. Further research is needed to quantify the risk and associated burden of transfusion-transmitted malaria (TTM) in order to inform strategies to prevent TTM.

Classification of induced malaria case in an elimination setting: investigation of transfusion-transmitted malaria cases

BackgroundSince the National Malaria Elimination Action Plan was launched in China in 2010, local malaria transmission has decreased rapidly. Zero indigenous cases were reported since 2017. However, after 2010, the proportion of imported cases in China increased from 45.7% in 2010 to 99.9% in 2016, and almost all provinces of China have reported imported cases in recent years. Prevention of the reintroduction of malaria into China is crucial for the maintenance of its malaria-free status. Hence, it is of utmost importance to correctly identify the source of malaria infections within the country.Case introduction and responseIn 2016 and 2017, three laboratory-confirmed cases of malaria caused by Plasmodium falciparum were identified in patients with no previous travel history to endemic areas were reported in Jiangsu Province, China, where malaria due to P. falciparum was eliminated about 30 years ago. These were diagnosed after 41, 31 and 39 days of seeking treatment, respectively, and all of them had received blood transfusions. Further investigations indicated that two of the cases had received blood from foreign students (from Indonesia and Ghana), and the other had received blood from an individual who had worked in Equatorial Guinea. All three blood donors were traced, and found to be carrying asymptomatic P. falciparum infections by microscopic examination and PCR. Furthermore, five polymorphic microsatellite markers (C1M4, C4M62, C13M13, C14M17, and C13M63) were typed and used to link parasites from the donors with those of the transfusion-receiving patients.ConclusionsThree transfusion-transmitted malaria cases were identified in China, all of which were due to the transfusion of blood donated by individuals who had contracted malaria outside the country. These cases can provide a reference for those faced with similar challenges in malaria case identification and classification in other regions. In addition, a stricter screening policy including the use of appropriate detection methods for malaria parasites should be developed and adopted for blood donation in regions undergoing malaria elimination.