Transfusion-Transmitted Malaria and Mitigation Strategies in Nonendemic Regions

Healthcare-associated malaria: a systematic review, 1997 to 2023

BackgroundMalaria is primarily transmitted through mosquito bites; occasionally, direct transmission through blood has been reported. Healthcare-associated infections refer to infections acquired in a hospital or another healthcare setting.AimThis systematic review aims to explore determinants of healthcare-associated malaria (HAM) cases.MethodThis review follows the PRISMA guidelines and was registered in PROSPERO (CRD42022309701). We searched five databases for publications on HAM cases published between 1 January 2000 and 7 December 2023. We initiated a data call for HAM cases to public health authorities from 37 European countries. We performed a backward and forward search, reviewed health authorities' websites, performed searches on Google and the European Scientific Conference on Applied Infectious Disease Epidemiology (ESCAIDE) conference abstracts book.ResultsWe identified 37 studies on HAM comprising 55 HAM cases, of which 35 (64%) were infected in Europe, primarily in Spain (nine cases), France and Italy (seven cases each). All cases were infected with Plasmodium falciparum except one individual. Fifty HAM cases were hospital inpatients and five were healthcare workers. Five patients died. Flushing of vascular catheters with contaminated heparin/saline solution and manipulation of intravenous catheters were the most frequently reported procedures leading to infection among patients.ConclusionsWhile rare, HAM transmission can be fatal. Healthcare-associated malaria is preventable through strict adherence to infection prevention and control procedures. Despite extensive investigations, the procedure leading to infection often remained unknown, highlighting the complexity of investigations. Guidance and protocols for conducting investigations may improve the success rate of such inquiries.

Estimated Plasmodium 18S ribosomal RNA prevalence in asymptomatic blood donors from three African countries

BACKGROUND AND OBJECTIVES

The World Health Organization (WHO) African Region accounts for 94% of malaria cases globally, with variability recognized within endemic regions. To determine the detection rate of Plasmodium RNA in blood donors resident in malaria-endemic areas, samples from three African countries were tested using a Plasmodium nucleic acid test.

MATERIALS AND METHODS

Whole blood (WB) samples collected from routine donors in Cameroon, Madagascar and Mali were shipped frozen to the United States. Samples were tested individually from WB lysates with the Procleix Plasmodium assay (transcription-mediated amplification [TMA]). Reactive samples were considered either repeat reactive or initial reactive only, depending on TMA-retest results. When available, matching plasma samples were tested for Plasmodium antibodies by enzyme immunoassay (EIA).

RESULTS

Plasmodium repeat reactivity ranged from 41% (91/223 tested) in Cameroon to 12% (26/216) in Mali and 1% (3/249) in Madagascar. Initially reactive samples, where reactivity did not repeat, were identified from Cameroon (5/223; 2%) and Mali (2/216; 1%). The matched-plasma subgroup had EIA reactivity ranging from 86% (113/131 tested) in Cameroon to 59% (10/17) in Mali and 27% (68/248) in Madagascar.

CONCLUSION

Plasmodium ribosomal RNA (rRNA) detection and antibody rates varied greatly in the three countries studied. Detection of Plasmodium rRNA can provide an additional tool to address malaria risk in blood donors.

Transmitted blood infections and emerging vector-borne diseases in blood donors in northern Portugal

BACKGROUND

Screening of transfusion-transmissible infectious agents of blood components is carried out in order to guarantee the safety of the transfusion process. The objective of this investigation was to characterize cases positive for transfusion-transmissible infectious agents in blood donations in the North of Portugal.

METHOD

Data from 2010 to 2022 of the Local Health Unit-Santo Antonio were used for this study. In specific epidemiological situations, malaria, Chagas disease and West Nile virus were screened.

MAIN RESULTS

Over 12 years, the health unit, received 137,751 donations with 108 positive tests. The proportions of human immunodeficiency viruses, syphilis, human hepatitis viruses type B and C varied between 0 and 44/100,000 donations. In this period, two cases of malaria were detected in 2020-2021, and 21 were detected in 2022 corresponding to 52.1/1000 donations screened. In 2022, two cases of Chagas disease and no cases of West Nile virus were detected.

CONCLUSION

These results highlight the importance of a rigorous investigation at the time of donation in which the donor's history, including origin and movement in areas of greater geographic risk, are assessed. The recent and increasing detection of cases of malaria and Chagas disease confirms the presence of emerging infectious diseases transmitted by vectors, including mosquitoes, in blood donors. The increased risk of vector-borne diseases in Europe is a public health problem and represents a new challenge in screening donations.

Laboratory detection of donors implicated in transfusion-transmitted malaria

BACKGROUND

Transfusion-transmitted malaria (TTM) is rare in non-endemic areas (non-EAs) but can potentially be fatal. This review analyzes the laboratory results of donors causing TTM in non-EAs, to assess the detectability of their Plasmodium infection by molecular or antibody tests.

STUDY DESIGN AND METHODS

TTM cases in the United States, Canada, and Europe since 2010 were identified through a literature review. Authors and laboratories were contacted for missing details about sample types and laboratory methods. Results of Plasmodium polymerase chain reaction (PCR) and antibody tests were summarized.

RESULTS

Twelve cases of TTM and one bone marrow transplant transmission were identified. Of the 13 source donors, 12 were tested by PCR, 10 were positive on at least one sample; the 2 negative donors were tested only on retained segments of blood refrigerated for several weeks. All donors were PCR positive on a fresh sample except one who was positive on a retained but not a fresh sample. These PCRs targeted Plasmodium DNA with sensitivities in the range of 1000-10,000 parasites/mL. Antibody EIA was positive in only three of seven donors tested.

DISCUSSION

This review found that antibody EIAs failed to detect four of the seven TTM donors tested. DNA-based PCRs were able to detect Plasmodium infection in all donors tested except for two tested only on samples likely to have deteriorated from prolonged storage. Recently developed ribosomal RNA-based molecular donor screening assays are approximately 1000 fold more sensitive than these DNA-based PCRs, holding promise as a potential method to further reduce TTM.

Dose-dependent inactivation of Plasmodium falciparum in red blood cell concentrates by treatment with short-wavelength ultraviolet light

BACKGROUND AND OBJECTIVES

Plasmodium species are naturally transmitted by Anopheles mosquitos. The parasite infects red blood cells (RBCs) and can be transfused with blood products. In non-endemic areas, the main risk of infection arises from travellers coming back and people immigrating from malaria-endemic regions. Endemic countries face a permanent risk of infection from transfusion-transmitted malaria (TTM). TTM may cause life-threatening complications in patients dependent on blood donations. This study aimed to investigate the efficacy of Plasmodium falciparum inactivation in RBC units by treatment with short-wavelength ultraviolet C (UVC) light in the absence of photochemical additives.

MATERIALS AND METHODS

RBC units were spiked with P. falciparum to a parasite density of 0.1%-1% and irradiated with up to 4.5 J/cm2 UVC. The parasite density of UVC-treated dilution series and untreated controls were compared over 3 weeks after irradiation.

RESULTS

The lowest dose of 1.5 J/cm2 UVC led to a 3.1 log reduction in parasite load compared with the untreated control. The inactivation capacity was dose-dependent. Strikingly, 4.5 J/cm2 led to ≥5.3 log unit reduction, which was equivalent to a complete inactivation in two out of three experiments.

CONCLUSION

Pathogen reduction with UVC light was previously shown to be effective for different bacteria and viruses, but the inactivation of parasites in RBC concentrates was not addressed until now. The present study provides evidence for significant inactivation of P. falciparum-infected RBCs by UVC light.

Plasmodium proteases and their role in development of Malaria vaccines

Malaria remains a major health hazard for humans, despite the availability of efficacious antimalarial drugs and other interventions. Given that the disease is often deadly for children under 5 years and pregnant women living in malaria-endemic areas, an efficacious vaccine to prevent transmission and clinical disease would be ideal. Plasmodium, the causative agent of malaria, uses proteases and protease inhibitors to control and process to invade host, modulate host immunity, and for pathogenesis. Plasmodium parasites rely on these proteases for their development and survival, including feeding their metabolic needs and invasion of both mosquito and human tissues, and have thus been explored as potential targets for prophylaxis. In this chapter, we have discussed the potential of proteases like ROM4, SUB2, SERA4, SERA5, and others as vaccine candidates. We have also discussed the role of some protease inhibitors of plasmodium and mosquito origin. Inhibition of plasmodium proteases can interrupt the parasite development at many different stages therefore understanding their function is key to developing new drugs and malaria vaccines.

A Model for Estimating the Burden of Disease of Transfusion-Transmitted Infection

Objectives

Blood transfusion is an important mode of infectious disease transmission in low- and middle-income countries (LMICs). This study describes a model to determine the prevalence of transfusion-transmitted infections (TTIs) and the associated burden of disease.

Methods

A five-step model was developed to determine the TTI-related burden of disease measured by disability-adjusted life years (DALYs). Uganda was selected as the study country.

Results

Approximately 298,266 units of blood were transfused in Uganda in 2019, yielding an estimated TTI incidence of 6,858 new TTIs (2.3% of transfused units) and prevalence of 19,141 TTIs (6.4% of transfused units). The total burden of disease is 2,903 DALYs, consisting of approximately 2,590 years of life lost (YLLs), and 313 years lived with disability (YLDs).

Conclusion

The incidence and prevalence of TTIs and the associated burden of disease can be calculated on a local and national level. The model can be applied by health ministries to estimate the impact of TTIs in order to develop blood safety strategies to reduce the burden of disease.

Patient socio-demographics and clinical factors associated with malaria mortality: a case control study in the northern region of Ghana

BACKGROUND

Ghana is a malaria-endemic country with the entire population at risk. The Northern region of the country recorded the highest malaria case fatality rate (CFR) for two consecutive years: 1.11% in 2013 and 1.07% in 2014. Even though the National Malaria Elimination Programme (NMEP) has achieved a reduction in malaria mortality, the existence of high case fatality in the Northern region was alarming. This study, therefore, aimed to determine the factors associated with malaria mortality in the northern region of Ghana to institute control measures.

METHODS

An unmatched case control study was conducted from July 2015 to August 2015. The study population consisted of patients admitted to health facilities for severe malaria in the Northern region of Ghana. A case was defined as a patient diagnosed with severe malaria at an eligible health facility who died as a result of malaria. A control was a patient diagnosed with severe malaria admitted to an eligible health facility who did not die. Health facilities that recorded CFRs of 1.0% and above were randomly sampled for this study, after which, 10 cases and 20 controls were recruited from each health facility. Information on cases and controls was then abstracted from hospital records using an electronically deployed abstraction tool. Continuous variables were expressed as means and medians, and categorical variables as frequencies and proportions. Multivariable logistic regression was used to assess the strength of the association between malaria mortality and factors predictive of malaria mortality. A p-value of < 0.05 was considered statistically significant.

RESULTS

In all, a total of 95 cases and 190 controls participated in this study. The median ages of cases and controls were 4.1 years (IQR = 21.6) and 5.7 years (IQR = 18.2), respectively. Fifty-four (56.8%) cases were females, while 93 (49.0%) of the controls were females. Factors associated with malaria mortality included: duration of hospital stay less than 24 h [aOR: 12.0, 95% CI (5.9-24.6)], severe pallor [aOR: 2.3, 95% CI (1.1-4.6)], children under 5 years [aOR: 2.8, 95% CI (1.4-5.6)], oral Artesunate/Amodiaquine administration [aOR: 0.4, 95% CI (0.2-0.9)] and sepsis as an additional diagnosis [aOR: 4.1, 95% CI (1.8-9.5)].

CONCLUSION

Predictors of malaria mortality in the Northern region include children under 5 years, severe pallor, sepsis as an additional diagnosis, and use of oral anti-malarial. Patients with severe pallor and sepsis as co-morbidities should receive proactive management. The NMEP and its partners should implement measures to strengthen the referral system, anaemia prevention and management, and retrain health workers on malaria case management. Malaria control interventions targeted at under five children in the region should be reviewed and enhanced.

Moleculargenetic and in Addition Partly Discrepant Infection Serological Malaria Testing in Two Blood Donors

Introduction

According to the guidelines (GL) valid in Germany, persons born or raised in a malaria-endemic area or had continuously stayed in a malaria-endemic area for more than 6 months may only be admitted donating blood if, among other things, validated and quality-assured laboratory diagnostics show that there is no evidence of infectivity. In a statement of the Working Group "Blood" of the Federal Ministry of Health (WGB), a reduction of the deferral period from 4 to 3 years and an antibody test after the deferral period are recommended.

Methods

In accordance with the GL, nucleic acid testing (NAT) by means of PCR is carried out at our institution after a retention period of 4 years. In addition to the validated molecular biological testing, an infection serological examination was performed.

Case Presentation

In the present cases, Plasmodia genome was detected in the respective single PCR in two blood donors originating from malaria-endemic areas after the expiry of the deferral period. However, one donor tested negative for antibodies against Plasmodia.

Discussion/Conclusion

This observation is discussed in the context of a recommendation of the WGB. The question is addressed whether PCR testing is dispensable or whether a combination of infection serological testing and NAT should be favored.

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

BACKGROUND

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.

STUDY DESIGN AND METHODS

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).

RESULTS

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.

DISCUSSION

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.