Delayed hemolysis after treatment with parenteral artesunate in African children with severe malaria--a double-center prospective study

Delayed Hemolysis With Parenteral Artesunate

Artesunate is an effective and first-line therapy option in patients with severe malaria caused by Plasmodium species. Among adverse effects of the drug is a phenomenon of delayed hemolysis. This usually occurs at least 7 days after initiation of therapy, and is characterized by reductions in hemoglobin and haptoglobin and an increase in lactate dehydrogenase. Here, we report an instance of delayed hemolysis in a patient probably attributed to parenteral artesunate therapy.

Post-artesunate Delayed Hemolysis in Patients With Severe Malaria in the United States-April 2019 Through July 2021

BACKGROUND

Studies have demonstrated the safety and efficacy of intravenous artesunate (IVAS) for treatment of severe malaria in endemic and nonendemic countries. However, post-artesunate delayed hemolysis (PADH) is an increasingly recognized phenomenon after its administration. This study describes the prevalence and outcomes of PADH events among severe malaria cases treated with IVAS in the United States.

METHODS

Patients diagnosed with severe malaria and treated with IVAS from April 2019 to July 2021 were included. Demographic, clinical, laboratory, therapeutic, and outcome measures were described using proportions, medians, and interquartile range. Patients reported to experience PADH were compared with those not reported to have PADH, and tests of significance were performed.

RESULTS

Of 332 patients included in our analysis, 9 (2.7%) experienced PADH. The majority of infections in both groups were in non-Hispanic Black individuals. Parasite density (11.0% vs 8.0%), admission hemoglobin (11.0 g/dL vs 11.8 g/dL) were similar in the 2 groups. Total bilirubin levels at admission (4.7 mg/dL vs 2.2 mg/dL) and within 8 hours after completion of IVAS (2.6 mg/dL vs 1.2 mg/dL) were notably higher in PADH patients. Cumulative IVAS dose of >9.5 mg/kg and >3 doses of IVAS were risk factors for PADH. The majority (7 of 9) of PADH cases were diagnosed within 2 weeks after initiation of IVAS. Five patients (56%) required blood transfusions, and all recovered without sequelae.

CONCLUSIONS

PADH is an uncommon and self-limiting adverse event in many cases; weekly monitoring of hemoglobin and hemolytic markers may identify cases requiring intervention in a timely manner.

Post-Artesunate Delayed Hemolysis: A Review of Current Evidence

Artesunate is the drug of choice for treating patients with severe malaria. Post-artesunate delayed hemolysis (PADH) is an uncommon adverse event from malaria treatment. Most patients with PADH are non-immune travelers. The pathophysiology of PADH is not fully understood, but the most likely mechanism is "pitting", in which red blood cells carrying dead parasites killed by artesunate's action are directed to the spleen for clearing the dead parasites. After the cleansing process, these red blood cells re-enter the circulation but with a smaller size and impaired integrity, resulting in a shortened lifespan of 7-21 days. Therefore, most patients with PADH usually present with clinical features of hemolytic anemia 7 days or later after the initiation of artesunate. To date, the benefits of artesunate treatment outweigh its adverse events, and no fatal cases have resulted from PADH. However, the hematological follow-up of patients with malaria treated with artesunate is recommended for clinicians to detect any delayed hemolytic event early and prevent potentially serious consequences.

Post-treatment haemolysis is common following oral artemisinin combination therapy of uncomplicated malaria in travellers

BACKGROUND

Artemisinin combination therapy (ACT) for the treatment of malaria is highly effective, well tolerated and safe. Episodes of delayed hemolysis occur in up to 57.9% of patients with severe malaria treated with intravenous artesunate, mainly caused by 'pitting' of infected red blood cells (RBCs) in the spleen and delayed loss of these once-infected RBCs (oiRBCs). Several reports indicate that post-treatment hemolysis (PTH) also occurs in uncomplicated malaria treated with oral ACT, calling for systematic investigation.

METHODS

Prospective observational study to identify the proportion of patients with PTH after oral ACT, defined as increased lactate dehydrogenase activity and low haptoglobin level on day 14 after treatment. Patients were enrolled at two study centres in Germany and Italy. Study visits took place on days 1, 3, 7, 14, 28. Laboratory investigations included extended clinical routine laboratory tests, quantitative P.f.-HRP2, anti-RBC antibodies, and oiRBCs. State of semi-immunity to malaria was assessed from childhood and ongoing exposure to Plasmodium spp. as per patient history.

RESULTS

A total of 134 patients with uncomplicated malaria and 3-day ACT treatment were recruited. Thirty-seven (37.4%) of 99 evaluable patients with P.f. and none of nine patients with non-P.f. malaria exhibited PTH on d14. Patients with PTH had higher initial parasitaemia, higher oiRBC counts on d3, and a 10-fold decrease in oiRBCs between d7 and d14 compared to patients without PTH. In patients with PTH, loss of haemoglobin (Hb) was 4-fold greater in non-Africans than in Africans (-1.3 vs -0.3 g/dl). Semi-immune African patients with PTH showed markedly increased erythropoiesis on d14 compared to not semi-immune African and non-African patients with PTH.

CONCLUSIONS

PTH is common in patients with uncomplicated malaria and oral ACT. While the observed loss of Hb will not be clinically relevant in most cases, it could aggravate pre-existing anaemia and warrants follow-up examinations in populations at risk.

Antimalarial treatment in infants

INTRODUCTION

Malaria in infants is common in high-transmission settings, especially in infants >6 months. Infants undergo physiological changes impacting pharmacokinetics and pharmacodynamics of anti-malarial drugs and, consequently, the safety and efficacy of malaria treatment. Yet, treatment guidelines and evidence on pharmacological interventions for malaria often fail to address this vulnerable age-group. This review aims to summarise the available data on anti-malarial treatment in infants.

AREAS COVERED

The standard recommended treatments for severe and uncomplicated malaria are generally safe and effective in infants. However, infants have an increased risk of drug-related vomiting and have distinct pharmacokinetic parameters of antimalarials compared with older patients. These include larger volumes of distribution, higher clearance rates and immature enzyme systems. Consequently, infants with malaria may be at increased risk of treatment failure and drug toxicity.

EXPERT OPINION

Knowledge expansion to optimize treatment can be achieved by including more infants in antimalarial drug trials and by reporting separately on treatment outcomes in infants. Additional evidence on the efficacy, safety, tolerability, acceptability and effectiveness of ACTs in infants is needed, as well as population pharmacokinetics studies on antimalarials in the infant population.

Blackwater fever and acute kidney injury in children hospitalized with an acute febrile illness: pathophysiology and prognostic significance

BACKGROUND

Acute kidney injury (AKI) and blackwater fever (BWF) are related but distinct renal complications of acute febrile illness in East Africa. The pathogenesis and prognostic significance of BWF and AKI are not well understood.

METHODS

A prospective observational cohort study was conducted to evaluate the association between BWF and AKI in children hospitalized with an acute febrile illness. Secondary objectives were to examine the association of AKI and BWF with (i) host response biomarkers and (ii) mortality. AKI was defined using the Kidney Disease: Improving Global Outcomes criteria and BWF was based on parental report of tea-colored urine. Host markers of immune and endothelial activation were quantified on admission plasma samples. The relationships between BWF and AKI and clinical and biologic factors were evaluated using multivariable regression.

RESULTS

We evaluated BWF and AKI in 999 children with acute febrile illness (mean age 1.7 years (standard deviation 1.06), 55.7% male). At enrollment, 8.2% of children had a history of BWF, 49.5% had AKI, and 11.1% had severe AKI. A history of BWF was independently associated with 2.18-fold increased odds of AKI (95% CI 1.15 to 4.16). When examining host response, severe AKI was associated with increased immune and endothelial activation (increased CHI3L1, sTNFR1, sTREM-1, IL-8, Angpt-2, sFlt-1) while BWF was predominantly associated with endothelial activation (increased Angpt-2 and sFlt-1, decreased Angpt-1). The presence of severe AKI, not BWF, was associated with increased risk of in-hospital death (RR, 2.17 95% CI 1.01 to 4.64) adjusting for age, sex, and disease severity.

CONCLUSIONS

BWF is associated with severe AKI in children hospitalized with a severe febrile illness. Increased awareness of AKI in the setting of BWF, and improved access to AKI diagnostics, is needed to reduce disease progression and in-hospital mortality in this high-risk group of children through early implementation of kidney-protective measures.

Treatment for Severe Malaria: Post-Artesunate Delayed Haemolysis and Neutropenia

Parenteral artesunate (AS) is the WHO first-line treatment recommended in adults and children for severe malaria. Post-artesunate delayed haemolysis (PADH) is an uncommon adverse reaction to AS with a mechanism that is not fully understood, occurring in adults and children. Neutropenia is another possible finding after AS treatment, albeit rare. We present the case of a child who experienced both effects after treatment with AS for imported severe Falciparum malaria with very high parasitaemia. In addition, thirty-five paediatric cases of PADH, five cases of delayed anaemia without known haemolysis, and fourteen cases of neutropenia after artesunate treatment were identified from the literature review. PADH seems to be a dose-independent reaction and is not strongly related to hyperparasitaemia, although it is more frequent in this case. To date, the benefits of AS outweigh its potential side effects. However, haematological follow-up is mandatory to avoid possible complications from anaemia and neutropenia, especially in children treated with other contemporary drugs.

Pediatric Malaria: Global and North American Perspectives

Malaria is a leading cause of death in children less than 5 years of age globally, and a common cause of fever in the returning North American traveler. New tools in the fight against malaria have been developed over the past decades: potent artemisinin derivatives; rapid diagnostic tests; long-lasting insecticidal bed nets; and a new vaccine, RTS,S/AS01. Thwarting these advances, parasite and Anopheles vector resistance are emerging. In the meantime, clinicians will continue to see malaria among febrile travelers from the tropics. Early recognition, diagnosis, and treatment can be lifesaving, but rely on the vigilance of frontline clinicians.

Delayed autoimmune haemolytic anaemia after artesunate therapy for severe malaria

We report the case of a 51-year-old man with severe malaria, who developed delayed autoimmune haemolytic anaemia following artesunate therapy. Delayed autoimmune haemolytic anaemia following artesunate therapy has been previously described. Its diagnosis can be challenging in the setting of possible dengue coinfection. Clinicians should be vigilant of this potential side effect of artesunate therapy, especially in patients who later develop signs and symptoms of haemolytic anaemia.

Fatal case of delayed-onset haemolytic anaemia after oral artemether-lumefantrine

Artemisinin derivatives are used globally in the management of falciparum malaria. Postartemisinin delayed haemolysis (PADH) is a recognised adverse event contributing to severe anaemia. To the best of our knowledge, we report the first recorded fatal case of PADH. A 60-year-old woman presented with two episodes of collapse at home and feeling generally unwell. She had recently been treated for uncomplicated falciparum malaria 1 month prior with artemether 80 mg/lumefantrine 480 mg in Congo. Her results on admission revealed an anaemia (haemoglobin 43 g/L), raised lactate dehydrogenase and positive direct antiglobulin test that suggested an intravascular haemolytic process. She made a capacitous decision to refuse blood products in line with her personal beliefs. Despite best supportive treatment, she did not survive. This case highlights the importance of postartemisinin follow-up and should encourage discussion and careful consideration of its use in the context of lack of access to/patient refusal of blood products.

Drug-induced hypersensitivity to artemisinin-based therapies for malaria

In the early 2000s, artemisinin-based combination therapy (ACT) was introduced as first-line treatment for uncomplicated Plasmodium falciparum malaria in virtually all endemic countries. However, despite the well-known excellent tolerability of ACTs, hypersensitivity to artemisinin derivatives remains a repeatedly documented adverse drug reaction of still unknown frequency. The clinical features of an artemisinin-induced hypersensitivity reaction range from mild to life-threatening severity, and a significant number of cases may pass unnoticed. In this review, we discuss the medical importance of hypersensitivity to artemisinin derivatives and we review data on the presumed frequency and its potential underlying mechanisms. Furthermore, we advocate to make alternative non-artemisinin-based drugs available for patients who do not tolerate artemisinin derivatives and to continue investing in the development of novel non-artemisinin-based combination regimens.

Pharmacotherapy for artemisinin-resistant malaria

INTRODUCTION

Malaria, the most devastating parasitic disease, is currently treated with artemisinin-based combination therapies (ACTs). Unfortunately, some ACTs are unable to rapidly clear Plasmodium falciparum parasites from the blood stream and are failing to cure malaria patients; a problem, so far, largely confined to Southeast Asia. There is a fear of resistant Plasmodium falciparum emerging in other parts of the world including Sub-Saharan Africa. Strategies for alternative treatments, ideally non-artemisinin based, are needed.

AREAS COVERED

This narrative review gives an overview of approved antimalarials and of some compounds in advanced drug development that could be used when an ACT is failing. The selection was based on a literature search in PubMed and WHO notes for malaria treatment.

EXPERT OPINION

The ACT drug class can still cure malaria in malaria endemic regions. However, the appropriate ACT drug should be chosen considering the background resistance of the partner drug of the local parasite population. Artesunate-pyronaridine, the 'newest' recommended ACT, and atovaquone-proguanil are, so far, effective, and safe treatments for uncomplicated falciparum malaria. Therefore, all available ACTs should be safeguarded from parasite resistance and the development of new antimalarial drug classes needs to be accelerated.

Post-Malaria Anemia Is Rare in Malawian Children with Cerebral Malaria

Artesunate therapy for severe malaria syndromes has been associated with post-treatment hemolysis and anemia. We defined post-malaria anemia as any decrease in hematocrit between the index hospitalization for severe malaria and 1 month after. We determined the incidence and severity of post-malaria anemia in Malawian children surviving cerebral malaria (CM) by analyzing hospital and follow-up data from a long-standing study of CM pathogenesis. Children enrolled before 2014 and treated with quinine (N = 258) were compared with those admitted in 2014 and after, and treated with artesunate (N = 235). The last hematocrit value obtained during hospitalization was compared with the 1-month post-hospitalization hematocrit value. The overall rate of a post-hospitalization decrease in hematocrit in children surviving CM was 5.3% (11 of 235 or 4.7% for quinine, 15 of 258 or 5.8% for artesunate; odds ratio, 3.23 [0.88, 18.38]); no patients with a decrease in hematocrit were symptomatic, and none required transfusion after hospitalization. Of the 26 children who had a decrease in hematocrit 1 month after hospitalization, 23.1% had evidence of a new malaria infection. When children treated with quinine and artesunate were combined, a higher hematocrit level on admission, lower quantitative histidine-rich protein level, and splenomegaly were associated independently with post-malaria anemia. In African survivors of CM, post-malaria anemia is rare, mild, and unassociated with the anti-malarial treatment received.

Severe Anemia Is Associated with Systemic Inflammation in Young Children Presenting to a Tertiary Hospital in Uganda

The role of inflammation in severe anemia (SA) in African children has not been well characterized. We conducted a study to evaluate risk factors for SA in young children admitted at a tertiary unit in Uganda. Clinical, infectious, and micronutrient risk factors for anemia, along with markers of inflammation, were evaluated in children aged < 5 years in Jinja Hospital, Uganda. Participants included 284 children with SA (Hemoglobin [Hb] < 5.0 g/dL), and two control groups: 63 children admitted with acute illness without SA (Hb > 9.3 g/dL) and 53 asymptomatic community control children. Appropriate logistic analysis was performed to determine factors associated with SA. Of the 284 children with SA, 36.5% had Plasmodium falciparum parasitemia, 32.7% had blackwater fever (one of the types of severe malaria), and 15.5% had vitamin B12 deficiency. HIV infection, bacteremia, hookworm infection, severe acute malnutrition, and folate deficiency were relatively uncommon (each accounting for < 8%). Factors independently associated with SA compared with the combined control groups included (adjusted odds ratio [OR]; 95% CI) the following: P. falciparum parasitemia (OR: 4.3; 95% CI: 1.4-13.8), total white blood count (OR: 1.3; 95% CI: 1.1-1.4), C-reactive protein (OR: 1.8; 95% CI: 1.3-2.4), and ferritin (OR: 2.7; 95% CI: 1.9-4.0). In this area of Uganda, malaria and markers of inflammation were independently associated with SA in children. Additional studies are required to determine the role of inflammation in children with SA in this population.

Post-malarial anemia in Mozambican children treated with quinine or artesunate: A retrospective observational study

OBJECTIVES

This retrospective analysis performed in Manhiça, Southern Mozambique, aimed to describe the frequency of post-malarial anemia (measured as a decrease of hematocrit ≥10%) and the need for blood transfusions in children with severe malaria treated with intravenous quinine or parenteral artesunate.

METHODS

All children <15 years admitted with a parasitologically-confirmed diagnosis of malaria from 1^st January 2003 to 31^st December 2017, alive at hospital discharge, and with at least one measurement of hematocrit within 28 days after hospital discharge, detected by passive case detection, were included.

RESULTS

The overall prevalence of post-malarial anemia observed in the study was 23.13%, with an estimated incidence rate of 288.84 episodes/1,000 children-month at risk in the follow-up period (28 days after discharge). There were no differences between treatment groups, although the study showed a higher association between blood transfusions and artesunate treatment.

CONCLUSIONS

In this setting, children with severe malaria frequently present a meaningful decrease of hematocrit (>=10%) in the first weeks after their episode, sometimes requiring blood transfusions. Because of the high underlying prevalence of anemia in malaria-endemic settings, all children with severe malaria need to be actively followed up, irrespective of the treatment received.

The Human Spleen in Malaria: Filter or Shelter?

The human spleen is an immune sentinel and controls red blood cell (RBC) quality. By mechanically retaining subsets of infected RBCs, the spleen may reduce the pace at which the parasite biomass increases before the adaptive immune response operates. Conversely, the spleen may contribute to malaria pathogenesis, particularly anemia that is associated with splenomegaly. Large spleens may also shelter parasites in chronic carriers. Upon treatment with artemisinins, the spleen clears circulating parasites by pitting and releases 'once-infected' RBCs in circulation. This triggers postartesunate delayed hemolysis and explains the long post-treatment positivity of histidine-rich protein 2 (HRP2)-based dipsticks. Importantly, splenic retention of RBCs also applies to gametocytes, the clearance of which may be enhanced by stiffening them with drugs, a potential way to block malaria transmission.

Anemia and transfusion requirements among Ugandan children with severe malaria treated with intravenous artesunate

Parenteral artesunate for the treatment of severe malaria in non-immune travelers is associated with late-onset hemolysis. In children in sub-Saharan Africa, the hematologic effects of malaria and artesunate are less well documented. Here we report a prospective case series of 91 children with severe malaria treated with parenteral artesunate, managed at a resource-poor hospital in Africa, with longitudinal data on hemoglobin (Hb), lactate dehydrogenase (LDH), haptoglobin, and erythrocyte morphology. The median (range) age was 2 (1-8) years and 43 (47%) were female. The median (IQR) admission Hb level was 69 (55-78) g/L and 20 patients (22%) had severe malarial anemia (Hb < 50 g/L). During hospitalization, 69 patients (76%) received one or more blood transfusions. Fatal outcome in 8 patients was associated with severe anemia in 6/8 cases. Follow-up Hb measurement was performed on 35 patients (38%) at day 14 after initial hospital admission; the remaining patients had no clinical evidence of anemia at the follow-up visit. The convalescent Hb was median (range) 90 (60-138) g/L, which was significantly higher than the paired admission levels (median increase +28 g/L, p < .001). Evidence of hemolysis (elevated LDH and low haptoglobin) was common at admission and improved by day 14. No patient met the standardized definition of post-artemisinin delayed hemolysis (PADH). In this cohort of young children with severe malaria treated with artesunate, anemia was common at admission, required one or more transfusions in a majority of patients, and markers of hemolysis had normalized by day 14.

Delayed haemolysis after treatment with intravenous artesunate in patients with severe malaria in India

Background

Parenteral artesunate is the treatment of choice for severe malaria. It is safe, efficacious and well tolerated anti-malarial. However, delayed haemolysis has been reported in travellers, non-immune individuals and in African children.

Methods

A prospective, observational study was carried out in admitted severe malaria patients receiving parenteral artesunate. The patients were followed up until day 28 for monitoring clinical as well as laboratory parameters for haemolytic anaemia.

Results

Twenty-four patients with severe malaria receiving injection artesunate were enrolled in the study. Post-artesunate delayed haemolysis following parenteral artesunate therapy was observed in three of 24 patients (12.5%, 95% confidence interval 4.5–31.2%). Haemolysis was observed in two more patients possibly due to other reasons. The haemoglobin fall ranged from 13.6 to 38.3% from day 7 to day 28 in these patients.

Conclusion

The possibility of delayed haemolysis should be considered while treating the severe malaria patients with parenteral artesunate. The study highlights the need for further studies in different epidemiological settings.

Determinants of post-malarial anemia in African children treated with parenteral artesunate

The pathophysiology of malarial anemia is multifactorial and incompletely understood. We assessed mechanistic and risk factors for post-malarial anemia in Ghanaian and Gabonese children with severe P. falciparum malaria treated with parenteral artesunate followed by an oral artemisinin-combination therapy. We analyzed data from two independent studies in which children were followed on Days 7,14, and 28 after treatment with artesunate. Specific hematological parameters included the presence of hemoglobinopathies and erythropoietin. Presence of once-infected erythrocytes was assessed by flow cytometry in a sub-population. Of 143 children with a geometric mean parasitemia of 116,294/µL (95% CI: 95,574-141,505), 91 (88%) had anemia (Hb < 10 g/dL) at presentation. Hemoglobin increased after Day 7 correlating with increased erythropoiesis through adequate erythropoietin stimulation. 22 children (24%) remained anemic until Day 28. Post-artesunate delayed hemolysis was detected in 7 children (5%) with only minor differences in the dynamics of once-infected erythrocytes. Hyperparasitemia and hemoglobin at presentation were associated with anemia on Day 14. On Day 28 only lower hemoglobin at presentation was associated with anemia. Most children showed an adequate erythropoiesis and recovered from anemia within one month. Post-artesunate delayed hemolysis (PADH) and hyperparasitemia are associated with early malarial anemia and pre-existing anemia is the main determinant for prolonged anemia.

Intravenous Artesunate for Imported Severe Malaria in Children Treated in Four Tertiary Care Centers in Germany: A Retrospective Study

BACKGROUND

Intravenous artesunate (ivA) is the standard treatment for severe malaria. Data systematically evaluating the use of ivA in pediatric patients outside malaria-endemic regions are limited. The aim of this case series was to summarize efficacy and safety of ivA for imported severe malaria in children in Germany.

METHODS

Our retrospective case series included pediatric patients with imported severe malaria treated with at least 1 dose of ivA (Artesun, Guilin Pharmaceutical; Shanghai, China) at 4 German tertiary care centers. Severe malaria was defined according to World Health Organization criteria.

RESULTS

Between 2010 and 2018, 14 children with a median [interquartile range (IQR)] age of 6 (1;9.5) years were included. All children were of African descent. All but 2 patients had Plasmodium falciparum malaria; 1 child had P. vivax malaria and 1 child had P. falciparum and P. vivax co-infection. Median (IQR) parasitemia at admission in patients with P. falciparum was 9.5% (3;16.5). Patients were treated with 1-10 [median (IQR) 3 (3;4)] doses ivA. All but one patient received a full course of oral antimalarial treatment. Parasite clearance was achieved within 2-4 days, with the exception of 1 patient with prolonged clearance of peripheral parasitemia. Three patients experienced posttreatment hemolysis but none needed blood transfusion. Otherwise ivA was safe and well tolerated.

CONCLUSIONS

ivA was highly efficacious in this pediatric cohort. We observed episodes of mild to moderate posttreatment hemolysis in approximately one-third of patients. The legal status and usage of potentially lifesaving ivA should be evaluated in Europe.

Clinical illness and outcomes in Nigerian children with persistent early-appearing anaemia following initiation of artemisinin-based combination treatments of uncomplicated falciparum malaria

In non-anaemic children with malaria, early-appearing anaemia (EAA) is common following artemisinin-based combination treatments (ACTs) and it may become persistent (PEAA). The factors contributing to and kinetics of resolution of the deficit in haematocrit from baseline (DIHFB) characteristic of ACTs-related PEAA were evaluated in 540 consecutive children with malaria treated with artemether-lumefantrine, artesunate-amodiaquine or dihydroartemisinin-piperaquine. Asymptomatic PEAA occurred in 62 children. In a multiple logistic regression model, a duration of illness ≤3 days before presentation, haematocrit <35% before and <25% one day after treatment initiation, drug attributable fall in haematocrit ≥6%, and treatment with dihydroartemisinin-piperaquine independently predicted PEAA. Overall, mean DIHFB was 5.7% (95% CI 4.8–6.6) 7 days after treatment initiation and was similar for all treatments. Time to 90% reduction in DIHFB was significantly longer in artemether-lumefantrine-treated children compared with other treatments. In a one compartment model, declines in DIHFB were monoexponential with overall mean estimated half-time of 3.9 days (95% CI 2.6–5.1), Cmax of 7.6% (95% CI 6.7–8.4), and Vd of 0.17 L/kg (95% CI 0.04–0.95). In Bland-Altman analyses, overall mean anaemia recovery time (AnRT) of 17.4 days (95% CI 15.5–19.4) showed insignificant bias with 4, 5 or 6 multiples of half-time of DIHFB. Ten children after recovery from PEAA progressed to late-appearing anaemia (LAA). Progression was associated with female gender and artesunate-amodiaquine treatment. Asymptomatic PEAA is common following ACTs. PEAA or its progression to LAA may have implications for case and community management of anaemia and for anaemia control efforts in sub-Saharan Africa where ACTs have become first-line antimalarials.

Trial registration: Pan Africa Clinical Trial Registration PACTR201709002064150, 1 March 2017 http://www.pactr.org

Delayed Hemolytic Anemia after Treatment with Artesunate: Case Report and Literature Review

BACKGROUND

In recent years, few cases of post-artemisinin delayed hemolysis have been reported.

OBJECTIVE

All cases of post-artemisinin delayed hemolysis were reported from non-middle east areas. No case of post-artemisinin delayed hemolysis has yet been reported from this region. In this paper, we describe a case of post-artemisinin delayed hemolysis in an Iranian female. Moreover, previous reports have been reviewed.

METHODS

Patient's data including demographic characteristics, past medical, drug and travelling history, present illness, vital signs, laboratory data, clinical course of current illness and follow-up findings were considered.

RESULTS

A 27-year-old female with a recent travel history to Ghana admitted with severe falciparum malaria. She was successfully treated with parenteral artesunate. However after 12 days of post artesunate treatment, she returned with dark urine, malaise and fatigue.

CONCLUSION

Considering the clinical course and base on a reliable causality assessment scale, post artesunate delay hemolytic anemia was possible.

Positive direct antiglobulin test in post-artesunate delayed haemolysis: more than a coincidence?

BACKGROUND

Delayed haemolysis is a frequent adverse event after treatment with artesunate (AS). Removing once-infected "pitted" erythrocytes by the spleen is the most accepted mechanism of haemolysis in these cases. However, an increasing number of cases with positive direct antiglobulin test (DAT) haemolysis after AS have been reported.

METHODS

All malaria cases seen at Hospital Clinic of Barcelona between 2015 and 2017 were retrospectively reviewed. Clinical, parasitological and laboratory data from patients treated with intravenous artesunate-specifically looking for delayed haemolysis and DAT-was collected.

RESULTS

Among the 36 severe malaria patients treated with artesunate at the hospital, 10 (27.8%) developed post-artesunate delayed haemolysis. Out of these, DAT was performed in six, being positive in four of them (at least 40%). DAT was positive only for complement-without IgG-suggesting drug-dependent immune-haemolytic anaemia of the immune-complex type. Three of the four patients were treated with corticosteroids and two also received blood transfusion, with a complete recovery.

CONCLUSIONS

Drug-induced auto-immune phenomena in post-artesunate delayed haemolysis may be underreported and must be considered. The role of corticosteroids should be reassessed.

Plasmodium falciparum Clearance Is Pitting-Dependent With Artemisinin-Based Drugs but Pitting-Independent With Atovaquone-Proguanil or Mefloquine

Pitting, the removal of dead parasites from their host erythrocyte, has been studied in patients with severe malaria treated parenterally with quinine or artesunate, and was recently shown to contribute to delayed hemolysis, a frequent adverse event of artesunate. We quantified pitting in 81 travelers treated with oral antimalarial therapy. Pitting rate was high (55.8%) with artemisinin-based combinations, but <10% with the nonartemisinin drugs quinine, mefloquine, and atovaquone-proguanil. This may, in part, explain the slower parasite clearance in patients treated with antimalarial drugs lacking an artemisinin component, as well as the absence of posttreatment hemolysis with these drugs.

Safety Experience During Real-World Use of Injectable Artesunate in Public Health Facilities in Ghana and Uganda: Outcomes of a Modified Cohort Event Monitoring Study (CEMISA)

Introduction

Injectable artesunate (Inj AS) is the World Health Organization (WHO)-recommended product for treating severe malaria. However, despite widespread usage, there are few published safety studies involving large populations in real-world settings. In this study, we sought to assess the incidence of common adverse events (AEs) following the intake of Inj AS in real-life settings.

Methods

This is a modified cohort event monitoring study involving patients who were administered with Inj AS at eight sites (four each in Ghana and Uganda) between May and December 2016. Patients were eligible for inclusion if they had severe/complicated malaria and were able and willing to participate in the study. Eligible patients were followed up by telephone or hospital or home visit on Days 7, 14, 21 and 28 after drug administration to document AEs and serious AEs (SAEs). Patients were also encouraged to report all AEs at any time during the study period. The Kaplan–Meier method was used to estimate the proportion of patients with any AEs by end of Day 28. Causality assessment was made on all AEs/SAEs using the WHO/UMC (Uppsala Monitoring Centre) causality method.

Results

A total of 1103 eligible patients were administered Inj AS, of which 360 patients were in Ghana and 743 in Uganda. The incidence of any AE by the end of follow-up among patients treated with AS was estimated to be 17.9% (197/1103) (95% confidence interval [CI] 15.8–20.3). The median time-to-onset of any AEs was 9 days (interquartile range (IQR) = 4, 14). The top five AEs recorded among patients treated with AS were pyrexia (3.5%), abdominal pain (2.5%), diarrhoea (1.7%), cough (1.5%) and asthenia (1.5%). Most of these top five AEs occurred in the first 14 days following treatment. Regarding the relatedness of these AEs to Inj AS, 78.9% of pyrexia (30/38), 63.0% of pain (17/27), 68.4% of diarrhoea (13/19), 85.5% of cough (14/16) and 75.0% of asthenia (12/16) were assessed as ‘possibly’ related. There were 17 SAEs including 13 deaths. Two of the deaths are ‘possibly’ related to Inj AS, as were three non-fatal SAEs: severe abdominal pain, failure of therapy and severe anaemia.

Conclusion

The incidence of common AEs among patients treated with Inj AS in real-world settings was found to be relatively low. Future studies should consider larger cohorts to document rare AEs as well.

ClinicalTrials.gov Identifier

NCT02817919.

When a transfusion in an emergency service is not really urgent: hyperhaemolysis syndrome in a child with sickle cell disease

A 13-month-old boy with sickle cell disease (SCD) from Equatorial Guinea, who had recently arrived in Spain, presented with fever. He had suffered from malaria and had received a blood transfusion. Following physical examination and complementary tests, intravenous antibiotics and a red blood cell (RBC) transfusion were administered. Soon after a second transfusion 5 days later, the haemoglobin level fell below pretransfusion levels, together with reticulocytopenia, and haematuria-the so-called hyperhaemolysis syndrome-requiring intensive care and treatment with intravenous immunoglobulins and corticosteroids, with resolution of the complication. We want to emphasise the importance of suspecting this rare, though severe complication that can appear after any RBC transfusion especially in patients with SCD, as the clinical syndrome can simulate other more common complications of these patients and a further transfusion is contraindicated. There is no standardised treatment, but intravenous immunoglobulin and corticosteroids are usually effective.

Hemolysis after Oral Artemisinin Combination Therapy for Uncomplicated Plasmodium falciparum Malaria

Episodes of delayed hemolysis 2-6 weeks after treatment of severe malaria with intravenous artesunate have been described. We performed a prospective observational study of patients with uncomplicated malaria to investigate whether posttreatment hemolysis also occurs after oral artemisinin-based combination therapy. Eight of 20 patients with uncomplicated malaria who were given oral artemisinin-based combination therapy met the definition of posttreatment hemolysis (low haptoglobin level and increased lactate dehydrogenase level on day 14). Five patients had hemolysis persisting for 1 month. Patients with posttreatment hemolysis had a median decrease in hemoglobin level of 1.3 g/dL (interquartile range 0.3-2.0 g/dL) in the posttreatment period, and patients without posttreatment hemolysis had a median increase of 0.3 g/dL (IQR -0.1 to 0.7 g/dL; p = 0.002). These findings indicate a need for increased vigilance for hemolytic events in malaria patients, particularly those with predisposing factors for anemia.

Severe delayed haemolytic anaemia associated with artemether-lumefantrine treatment of malaria in a Japanese traveller

Delayed haemolytic anaemia has been reported in association with intravenous artesunate treatment in patients with severe Plasmodium falciparum malaria, and furthermore, oral artemisinin-based combination therapies including artemether-lumefantrine (AL) have also been incriminated. However, definite cases of delayed haemolytic anaemia associated with AL appear to be scarce, as reported cases were often treated concomitantly with other anti-malarials. In this study, we report a severe case of delayed haemolytic anaemia following AL alone in a Japanese traveller with severe parasitaemia caused by numerous P. falciparum parasites and a few P. vivax parasites. We also stress the need by further studies to differentiate between delayed haemolytic anaemia and blackwater fever, the latter being another malaria-related haemolytic condition, more clearly than they are now.

Post-treatment haemolysis in African children with hyperparasitaemic falciparum malaria; a randomized comparison of artesunate and quinine

Background

Parenteral artesunate is the treatment of choice for severe malaria. Recently, haemolytic anaemia occurring 1 to 3 weeks after artesunate treatment of falciparum malaria has been reported in returning travellers in temperate countries.

Methods

To assess these potential safety concerns in African children, in whom most deaths from malaria occur, an open-labelled, randomized controlled trial was conducted in Kinshasa, Democratic Republic of Congo. 217 children aged between 6 months and 14 years with acute uncomplicated falciparum malaria and parasite densities over 100,000/μL were randomly allocated to intravenous artesunate or quinine, hospitalized for 3 days and then followed for 42 days.

Results

The immediate reduction in haemoglobin was less with artesunate than with quinine: median (IQR) fall at 72 h 1.4 g/dL (0.90–1.95) vs. 1.7 g/dL (1.10–2.40) (p = 0.009). This was explained by greater pitting then recirculation of once infected erythrocytes. Only 5% of patients (in both groups) had a ≥ 10% reduction in haemoglobin after day 7 (p = 0.1). One artesunate treated patient with suspected concomitant sepsis had a protracted clinical course and required a blood transfusion on day 14.

Conclusions

Clinically significant delayed haemolysis following parenteral artesunate is uncommon in African children hospitalised with acute falciparum malaria and high parasitaemias.

Trial registration

ClinicalTrials.gov; Identifier: NCT02092766 (18/03/2014)

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2678-0) contains supplementary material, which is available to authorized users.

High Frequency of Blackwater Fever Among Children Presenting to Hospital With Severe Febrile Illnesses in Eastern Uganda

BACKGROUND

In the Fluid Expansion as a Supportive Treatment (FEAST) trial, an unexpectedly high proportion of participants from eastern Uganda presented with blackwater fever (BWF).

METHODS

We describe the prevalence and outcome of BWF among trial participants and compare the prevalence of 3 malaria-protective red blood cell polymorphisms in BWF cases vs both trial (non-BWF) and population controls.

RESULTS

Of 3170 trial participants, 394 (12.4%) had BWF. The majority (318 [81.0%]) presented in eastern Uganda and were the subjects of further analysis. BWF cases typically presented with both clinical jaundice (254/318 [80%]) and severe anemia (hemoglobin level <5 g/dL) (238/310 [77%]). Plasmodium falciparum parasitemia was less frequent than in non-BWF controls, but a higher proportion were positive for P. falciparum histidine rich protein 2 (192/246 [78.0%]) vs 811/1154 [70.3%]; P = .014), suggesting recent antimalarial treatment. Overall, 282 of 318 (88.7%) received transfusions, with 94 of 282 (33.3%) and 9 of 282 (3.4%) receiving 2 or 3 transfusions, respectively. By day 28, 39 of 318 (12.3%) BWF cases and 154 of 1554 (9.9%) non-BWF controls had died (P = .21), and 7 of 255 (3.0%) vs 13/1212 (1%), respectively, had severe anemia (P = .036). We found no association with G6PD deficiency. The prevalence of both the sickle cell trait (10/218 [4.6%]) and homozygous α+thalassemia (8/216 [3.7%]) were significantly lower among cases than among population controls (334/2123 [15.7%] and 141/2114 [6.6%], respectively), providing further support for the role of malaria.

CONCLUSIONS

We report the emergence of BWF in eastern Uganda, a condition that, according to local investigators, was rare until the last 7 years. We speculate that this might relate to the introduction of artemisinin-based combination therapies. Further studies investigating this possibility are urgently required.

Artesunate to treat severe malaria in travellers: review of efficacy and safety and practical implications

BACKGROUND

Artesunate (AS) is the WHO first-line treatment of severe malaria in endemic countries, in adults and children. However, despite solid evidence that AS is safe and more effective than quinine in endemic areas, its deployment in non-endemic areas has been slow, due in part to the absence of a full good manufacturing practice (GMP) qualification (although prequalification has been granted in 2010). Prospective comparative trials were not conducted in travellers, but several retrospective studies and case reports are providing insights into the efficacy and safety of AS in imported severe malaria.

METHODS

We performed a systematic review on AS use in non-endemic areas for the treatment of imported severe malaria, using the Prisma method for bibliographic reports. Post-AS delayed haemolysis (PADH) was defined by delayed haemolytic episodes occurring 7-30 days after treatment initiation. We summarized prescription guidelines and generated answers to frequently asked questions regarding the use of AS in travellers with severe malaria.

RESULTS

We analysed 12 retrospectives and 1 prospective study as well as 7 case reports of AS treatment in 624 travellers. Of 574 patients with reported outcome, 23 died (4%). No death was attributed to AS toxicity. Non-haematological side effects were uncommon and mainly included mild hepatitis, neurological, renal, cutaneous and cardiac manifestations. PADH occurred in 15% of the treated patients. No death or sequelae were reported. Overall blood transfusion was administered in 50% of travellers with PADH.

CONCLUSION

AS is highly efficacious in travellers with severe malaria. The frequency of PADH supports the need of weekly follow-up of haematological parameters during 1 month. Full GMP qualification for the drug and rapid approval by drug agencies is warranted, backed by clear recommendations for optimal use.

Development of Delayed Hemolytic Anemia After Treatment with Oral Artemether-Lumefantrine in Two Patients with Severe Falciparum Malaria

AbstractRecently, reports of delayed hemolytic anemia after treatment with artemisinin and its derivatives have emerged. Here we report two cases of delayed hemolytic anemia in a patient with severe falciparum malaria after treatment with oral artemether-lumefantrine (AL). The first patient, a 20-year-old Japanese male student, was diagnosed with falciparum malaria and was administered AL. As having a high parasitemia rate (20.6%) was the only severe malaria criterion met in this case and his general condition was stable, we continued with AL treatment. Despite disappearance of malarial parasites after 4 days of AL administration, a persistent fever remained. On days 13 and 16, a diagnosis of hemolytic anemia was made (lactate dehydrogenase [LDH]: 1,466 U/L, hemoglobin [Hb]: 7.2 g/dL). A blood smear at that time revealed no parasites. He recovered naturally from delayed hemolysis. The second patient, a 27-year-old Japanese female student, was diagnosed with falciparum malaria (parasitemia: 4.5%) and treated initially with oral quinine hydrochloride and doxycycline. The following day, parasitemia increased to 7.9% and oral AL was initiated. She was discharged on day 4 after achieving parasite clearance and afebrility. However, on day 5, fever (body temperature > 38°C) recurred, and on day 11, a diagnosis of hemolytic anemia was made (LDH: 712 U/L, Hb: 8.8 g/dL). A follow-up confirmed that her condition improved gradually. AL treatment of severe malaria can cause delayed hemolytic anemia. Patients should be followed up for up to 4 weeks to detect signs of hemolysis and provide appropriate symptomatic treatment.

Therapeutic efficacy and effects of artemisinin-based combination treatments on uncomplicated Plasmodium falciparum malaria -associated anaemia in Nigerian children during seven years of adoption as first-line treatments

BACKGROUND

Artemisinin-based combination treatments (ACTs) are the first-line treatments of uncomplicated Plasmodium falciparum malaria in many endemic areas but there are few evaluation of their efficacy in anaemic malarious children.

METHODS

Therapeutic efficacy of 3-day regimens of artesunate-amodiaquine and artemether-lumefantrine was evaluated in 437 anaemic and 909 non-anaemic malarious children following treatment during a seven-year period (2008-2014). Patterns of temporal changes in haematocrit were classified based on haematocrit values <30% and ≥30%. Kinetics of the disposition of the deficit in haematocrit from 30% following treatment were evaluated using a non-compartment model.

RESULTS

PCR-corrected parasitological efficacy 28 days after start of treatment was significantly higher in artesunate-amodiaquine- compared to artemether-lumefantrine-treated children [97% (95%CI: 92.8-100) versus 96.4% (95%CI: 91.3-99.4), P = 0.02], but it was similar in non-anaemic and anaemic children. Fall in haematocrit/1 000 asexual parasites cleared from peripheral blood was significantly greater at lower compared to higher parasitaemias (P < 0.0001), and in non-anaemic compared to anaemic children (P = 0.007). In anaemic children at presentation, mean anaemia recovery time (AnRT) was 15.4 days (95%CI: 13.3-17.4) and it did not change over the years. Declines in haematocrit deficits from 30% were monoexponential with mean estimated half-time of 1.4 days (95%CI: 1.2-1.6). Anaemia half-time (t½anaemia) correlated positively with AnRT in the same patients (r = 0.69, P < 0.0001). Bland-Altman analysis of 10 multiples of t½anaemia and AnRT showed narrow limit of agreement with insignificant bias (P = 0.07) suggesting both can be used interchangeably in the same patients.

CONCLUSIONS

Artesunate-amodiaquine and artemether-lumefantrine remain efficacious treatments of uncomplicated P. falciparum infections in non-anaemic and anaemic Nigerian children in the last 7 years of adoption as first-line treatments. These ACTs may also conserve haematocrit at high parasitaemias and in anaemic children.

TRIALS REGISTRATION

Pan African Clinical Trial Registry PACTR201508001188143 , 3 July 2015; PACTR201510001189370 , 3 July 2015; PACTR201508001191898 , 7 July 2015 and PACTR201508001193368 , 8 July 2015.

No Reduction in Hemoglobin Level in Severe Plasmodium falciparum Malaria Treated with Artesunate in Central Sudan

BACKGROUND

There are few publications on anemia following artesunate treatment.

OBJECTIVE

To investigate the hemoglobin in patients with severe Plasmodium falciparum malaria treated with artesunate or quinine.

METHODS

Patients with P. falciparum (in Singa, Sudan) were treated by intravenous artesunate or quinine. Hemoglobin was measured initially, at day 14 and day 28.

RESULTS

The mean (SD) of the age was 10.3 (10.9) years. The two groups (61 in each arm) were matched in their basic characteristics. Hypotension, convulsions, severe anemia were the main presentations. There was no significant difference in the mean (SD) hemoglobin level at the initial day, day 14 and at day 28 [11.2 (1.8), 11.3 (1.6), 11.5 (1.8), p = 0.170], respectively, in both groups. The hemoglobin did not change significantly from the baseline in any of the group separately.

CONCLUSION

There was no difference in hemoglobin concentration in patients with severe malaria after treatment with either artesunate or quinine.

Severe malaria in Europe: an 8-year multi-centre observational study

Background

Malaria remains one of the most serious infections for travellers to tropical countries. Due to the lack of harmonized guidelines a large variety of treatment regimens is used in Europe to treat severe malaria.

Methods

The European Network for Tropical Medicine and Travel Health (TropNet) conducted an 8-year, multicentre, observational study to analyse epidemiology, treatment practices and outcomes of severe malaria in its member sites across Europe. Physicians at participating TropNet centres were asked to report pseudonymized retrospective data from all patients treated at their centre for microscopically confirmed severe Plasmodium falciparum malaria according to the 2006 WHO criteria.

Results

From 2006 to 2014 a total of 185 patients with severe malaria treated in 12 European countries were included. Three patients died, resulting in a 28-day survival rate of 98.4%. The majority of infections were acquired in West Africa (109/185, 59%). The proportion of patients treated with intravenous artesunate increased from 27% in 2006 to 60% in 2013. Altogether, 56 different combinations of intravenous and oral drugs were used across 28 study centres. The risk of acute renal failure (36 vs 17% p = 0.04) or cerebral malaria (54 vs 20%, p = 0.001) was significantly higher in patients ≥60 years than in younger patients. Respiratory distress with the need for mechanical ventilation was significantly associated with the risk of death in the study population (13 vs 0%, p = 0.001). Post-artemisinin delayed haemolysis was reported in 19/70 (27%) patients treated with intravenous artesunate.

Conclusion

The majority of patients with severe malaria in this study were tourists or migrants acquiring the infection in West Africa. Intravenous artesunate is increasingly used for treatment of severe malaria in many European treatment centres and can be given safely to European patients with severe malaria. Patients treated with intravenous artesunate should be followed up to detect and manage late haemolytic events.

Delayed haemolysis secondary to treatment of severe malaria with intravenous artesunate: Report on the experience of a referral centre for tropical infections in Spain

BACKGROUND

Post-artesunate delayed haemolysis is described as hemolytic anemia presenting days after malaria treatment in hyperparasitemic patients. Physiopathological mechanisms and clinical manifestations have not been thoroughly characterised.

METHODS

We conducted a retrospective study of hospitalised malaria patients who received artemisinin derivatives from January 1, 2010 to December 31, 2015.

RESULTS

21 patients were included in the study: 11 travellers, 8 travellers visiting friends and relatives and 2 immigrants. Median age was 35.5 years (IQR: 25.7-44.8) and 11 were men. Eight patients received oral and 13 received intravenous (IV) artemisinin-based drugs. Follow-up after the malaria episode was available for 15 patients (12 with IV treatment). Four patients presented with delayed haemolysis 9-14 days after artesunate treatment; all had been admitted with severe malaria, were treated IV and had hyperparasitaemia (17%-33%). Other than hyperparasitaemia, no other factors were associated with artesunate haemolysis. Patients' outcomes were favourable and the only additional therapeutic measure needed was a blood transfusion.

CONCLUSIONS

Delayed haemolysis is a frequent complication in hyperparasitemic malaria treated with IV artesunate. Follow-up is mandatory for at least 2 weeks after treatment initiation. This condition is potentially severe but does not appear to be life threatening.

Anti-Self Phosphatidylserine Antibodies Recognize Uninfected Erythrocytes Promoting Malarial Anemia

Plasmodium species, the parasitic agents of malaria, invade erythrocytes to reproduce, resulting in erythrocyte loss. However, a greater loss is caused by the elimination of uninfected erythrocytes, sometimes long after infection has been cleared. Using a mouse model, we found that Plasmodium infection induces the generation of anti-self antibodies that bind to the surface of uninfected erythrocytes from infected, but not uninfected, mice. These antibodies recognize phosphatidylserine, which is exposed on the surface of a fraction of uninfected erythrocytes during malaria. We find that phosphatidylserine-exposing erythrocytes are reticulocytes expressing high levels of CD47, a "do-not-eat-me" signal, but the binding of anti-phosphatidylserine antibodies mediates their phagocytosis, contributing to anemia. In human patients with late postmalarial anemia, we found a strong inverse correlation between the levels of anti-phosphatidylserine antibodies and plasma hemoglobin, suggesting a similar role in humans. Inhibition of this pathway may be exploited for treating malarial anemia.

Asiatic acid influences parasitaemia reduction and ameliorates malaria anaemia in P. berghei infected Sprague-Dawley male rats

BACKGROUND

Current malaria treatment is either "anti-parasitic", "anti-infectivity" or both without addressing the pathophysiological derangement (anti-disease aspect) associated with the disease. Asiatic acid is a natural phytochemical with oxidant, antioxidant and anti-inflammatory properties whose effect on malarial and accompanying pathophysiology are yet to be investigated. Asiatic acid influence in P. berghei-infected Sprague Dawley rats on %parasitaemia and malarial anaemia were investigated.

METHODS

Plasmodium berghei-infected rats (90-120 g) were orally administered with Asiatic acid (5, 10, 20 mg/kg) and 30 mg/kg chloroquine as a positive control. Changes in %parasitaemia and haematological parameters in Asiatic acid administered rats were monitored in a 21 day study and compared to controls.

RESULTS

All animals developed stable parasitaemia (15-20 %) by day 7. Asiatic acid doses suppressed parasitaemia, normalised haematological measurements and influenced biophysical characteristics changes. Most positive changes were associated with intragastric administration of 10 mg/kg Asiatic acid dose. Peak %parasitaemia in Asiatic acid administration occurred at days 12 with a shorter time course compared to day 9 for chloroquine (30 mg/kg) treatment with a longer time course.

CONCLUSIONS

Oral Asiatic acid administration influenced %parasitaemia suppression, ameliorated malarial anaemia and increased biophysical properties on infected animals. Asiatic acid may be a replacement alternative for chloroquine treatment with concomitant amelioration of malaria pathophysiology. Due to different action time courses, Asiatic acid and chloroquine may be possible candidates in combination therapy.

Therapeutic efficacy and effects of artesunate-amodiaquine and artemether-lumefantrine on malaria-associated anaemia in Nigerian children aged two years and under

BACKGROUND

Artemisinin-based combination therapies are recommended as first-line treatments for uncomplicated falciparum malaria, but there is little evaluation of their efficacy and effects on uncomplicated malaria-associated anaemia in children aged 2 years and under.

METHODS

Parasitological efficacy and effects on malaria-associated anaemia were evaluated in 250 malarious children aged 2 years and under, and efficacy was evaluated in 603 malarious children older than two but younger than 5 years of age following treatment with artesunate-amodiaquine (AA) or artemether-lumefantrine (AL). Kinetics of the disposition of parasitaemia following treatment were evaluated using a non-compartment model. Late-appearing anaemia (LAA) was diagnosed using the following criteria: clearance of parasitaemia, fever and other symptoms occurring within 7 days of starting treatment, adequate clinical and parasitological response on days 28-42, haematocrit (HCT) ≥ 30 % at 1 and/or 2 weeks, a fall in HCT to < 30 % occurring at 3-6 weeks, absence of concomitant illness at 1-6 weeks, and absence of asexual parasitaemia detected using both microscopy and polymerase chain reaction (PCR) at 1-6 weeks.

RESULTS

Overall, in children aged 2 years and under, the PCR-corrected parasitological efficacy was 97.2 % (95 % CI 92.8-101.6), which was similar for both treatments. In children older than 2 years, parasitological efficacy was also similar for both treatments, but parasite prevalence 1 day after treatment began was significantly higher, and fever and parasite clearance times were significantly faster in the AA-treated children compared with the AL-treated children. Declines in parasitaemia were monoexponential with an estimated elimination half-time of 1 h. Elimination half-times were similar for both treatments. In children aged 2 years and under who were anaemic at presentation, the mean anaemia recovery time was 12.1 days (95 % CI 10.6-13.6, n = 127), which was similar for both treatments. Relatively asymptomatic LAA occurred in 11 children (4.4 %) aged 2 years and under, the recovery from which was uneventful.

CONCLUSION

This study showed that AA and AL are efficacious treatments for uncomplicated falciparum malaria in Nigerian children aged 2 years and under, and that AA clears parasitaemia and fever significantly faster than AL in children older than 2 years. Both treatments may cause a relatively asymptomatic LAA with uneventful recovery in a small proportion of children aged 2 years and under.

TRIALS REGISTRATION

Pan African Clinical Trial Registry PACTR201508001188143, 3 July 2015; PACTR201510001189370, 3 July 2015; PACTR201508001191898, 7 July 2015 and PACTR201508001193368, 8 July 2015  http://www.pactr.org .

Clinical illness and outcomes in Nigerian children with late-appearing anaemia after artemisinin-based combination treatments of uncomplicated falciparum malaria

Background

Late-appearing anaemia (LAA) following treatment with artemisinins for severe malaria has been reported and well described, but there are limited clinical and parasitological data on LAA in African children with uncomplicated falciparum malaria following oral artemisinin-based combination therapies (ACTs).

Methods

This was an open label study with the main objectives of evaluating the clinical features, the risk factors for, the temporal changes in haematocrit and the outcomes of a LAA in malarious children treated with artesunate-amodiaquine (AA), artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DHP). The diagnosis of LAA was made using the criteria: clearance of parasitaemia, fever and other symptoms within 1 week of commencing treatment; adequate clinical and parasitological response at 4–6 weeks after treatment began; haematocrit ≥30 % 1 and/or 2 weeks after treatment began; and haematocrit <30 %, parasite negativity by microscopy and polymerase chain reaction and absence of concomitant illness 3–6 weeks after treatment began.

Results

LAA occurred in 84 of 609 children, was mild, moderate or severe in 77, 6 or 1 child, respectively and was relatively asymptomatic. Mean time elapsing from commencement of treatment to LAA was 27.1 days (95 % CI 25.3–28.9). In a multivariate analysis, an age <3 years (adjusted odd ratio [AOR] = 2.6, 95 % CI 1.3–5.2, P = 0.005), fever 1 day after treatment began (AOR = 3.8, 95 % CI 1.8–8.2, P < 0.0001), haematocrit <25 % at presentation (AOR = 2.2, 95 % CI 1.3–3.7, P = 0.003), haematocrit <30 % 1 day after treatment began (AOR = 2.1, 95 % CI 1.0–4.3, P = 0.04), parasite reduction ratio >10⁴ 2 days after treatment began (AOR = 2.1, 95 % CI 1.1–3.9, P = 0.03) and spleen enlargement at presentation (AOR = 2.0, 95 % CI 1.1–3.9, P < 0.0001) were independent predictors of LAA. During 6 weeks of follow-up, uneventful recovery from anaemia occurred in 56 children [mean recovery time of 11.8 days (95 % CI 10.3–13.3)]. The only independent predictor of failure of recovery was LAA occurring 4 weeks after starting treatment (AOR = 7.5, 95 % CI 2.5–22.9, P < 0.0001).

Conclusion

A relatively asymptomatic LAA with uneventful recovery can occur in young malarious children following ACTs. Its occurrence may have implications for case and community management of anaemia and for anaemia control efforts in sub–Saharan Africa where ACTs have become first-line antimalarials.

Trials registration

Pan African Clinical Trial Registry PACTR201508001188143, 3 July 2015; PACTR201510001189370, 3 July 2015; PACTR201508001191898, 7 July 2015 and PACTR201508001193368, 8 July 2015 http://www.pactr.org.

UK malaria treatment guidelines 2016

1.Malaria is the tropical disease most commonly imported into the UK, with 1300-1800 cases reported each year, and 2-11 deaths. 2. Approximately three quarters of reported malaria cases in the UK are caused by Plasmodium falciparum, which is capable of invading a high proportion of red blood cells and rapidly leading to severe or life-threatening multi-organ disease. 3. Most non-falciparum malaria cases are caused by Plasmodium vivax; a few cases are caused by the other species of plasmodium: Plasmodium ovale, Plasmodium malariae or Plasmodium knowlesi. 4. Mixed infections with more than one species of parasite can occur; they commonly involve P. falciparum with the attendant risks of severe malaria. 5. There are no typical clinical features of malaria; even fever is not invariably present. Malaria in children (and sometimes in adults) may present with misleading symptoms such as gastrointestinal features, sore throat or lower respiratory complaints. 6. A diagnosis of malaria must always be sought in a feverish or sick child or adult who has visited malaria-endemic areas. Specific country information on malaria can be found at http://travelhealthpro.org.uk/. P. falciparum infection rarely presents more than six months after exposure but presentation of other species can occur more than a year after exposure. 7. Management of malaria depends on awareness of the diagnosis and on performing the correct diagnostic tests: the diagnosis cannot be excluded until more than one blood specimen has been examined. Other travel related infections, especially viral haemorrhagic fevers, should also be considered. 8. The optimum diagnostic procedure is examination of thick and thin blood films by an expert to detect and speciate the malarial parasites. P. falciparum and P. vivax (depending upon the product) malaria can be diagnosed almost as accurately using rapid diagnostic tests (RDTs) which detect plasmodial antigens. RDTs for other Plasmodium species are not as reliable. 9. Most patients treated for P. falciparum malaria should be admitted to hospital for at least 24 h as patients can deteriorate suddenly, especially early in the course of treatment. In specialised units seeing large numbers of patients, outpatient treatment may be considered if specific protocols for patient selection and follow up are in place. 10. Uncomplicated P. falciparum malaria should be treated with an artemisinin combination therapy (Grade 1A). Artemether-lumefantrine (Riamet(®)) is the drug of choice (Grade 2C) and dihydroartemisinin-piperaquine (Eurartesim(®)) is an alternative. Quinine or atovaquone-proguanil (Malarone(®)) can be used if an ACT is not available. Quinine is highly effective but poorly-tolerated in prolonged treatment and should be used in combination with an additional drug, usually oral doxycycline. 11. Severe falciparum malaria, or infections complicated by a relatively high parasite count (more than 2% of red blood cells parasitized) should be treated with intravenous therapy until the patient is well enough to continue with oral treatment. Severe malaria is a rare complication of P. vivax or P. knowlesi infection and also requires parenteral therapy. 12. The treatment of choice for severe or complicated malaria in adults and children is intravenous artesunate (Grade 1A). Intravenous artesunate is unlicensed in the EU but is available in many centres. The alternative is intravenous quinine, which should be started immediately if artesunate is not available (Grade 1A). Patients treated with intravenous quinine require careful monitoring for hypoglycemia. 13. Patients with severe or complicated malaria should be managed in a high-dependency or intensive care environment. They may require haemodynamic support and management of: acute respiratory distress syndrome, disseminated intravascular coagulation, acute kidney injury, seizures, and severe intercurrent infections including Gram-negative bacteraemia/septicaemia. 14. Children with severe malaria should also be treated with empirical broad spectrum antibiotics until bacterial infection can be excluded (Grade 1B). 15. Haemolysis occurs in approximately 10-15% patients following intravenous artesunate treatment. Haemoglobin concentrations should be checked approximately 14 days following treatment in those treated with IV artemisinins (Grade 2C). 16. Falciparum malaria in pregnancy is more likely to be complicated: the placenta contains high levels of parasites, stillbirth or early delivery may occur and diagnosis can be difficult if parasites are concentrated in the placenta and scanty in the blood. 17. Uncomplicated falciparum malaria in the second and third trimester of pregnancy should be treated with artemether-lumefantrine (Grade 2B). Uncomplicated falciparum malaria in the first trimester of pregnancy should usually be treated with quinine and clindamycin but specialist advice should be sought. Severe malaria in any trimester of pregnancy should be treated as for any other patient with artesunate preferred over quinine (Grade 1C). 18. Children with uncomplicated malaria should be treated with an ACT (artemether-lumefantrine or dihydroartemisinin-piperaquine) as first line treatment (Grade 1A). Quinine with doxycycline or clindamycin, or atovaquone-proguanil at appropriate doses for weight can also be used. Doxycycline should not be given to children under 12 years. 19. Either an oral ACT or chloroquine can be used for the treatment of non-falciparum malaria. An oral ACT is preferred for a mixed infection, if there is uncertainty about the infecting species, or for P. vivax infection from areas where chloroquine resistance is common (Grade 1B). 20. Dormant parasites (hypnozoites) persist in the liver after treatment of P. vivax or P. ovale infection: the only currently effective drug for eradication of hypnozoites is primaquine (1A). Primaquine is more effective at preventing relapse if taken at the same time as chloroquine (Grade 1C). 21. Primaquine should be avoided or given with caution under expert supervision in patients with Glucose-6-phosphate dehydrogenase deficiency (G6PD), in whom it may cause severe haemolysis. 22. Primaquine (for eradication of P. vivax or P. ovale hypnozoites) is contraindicated in pregnancy and when breastfeeding (until the G6PD status of child is known); after initial treatment for these infections a pregnant woman should take weekly chloroquine prophylaxis until after delivery or cessation of breastfeeding when hypnozoite eradication can be considered. 23. An acute attack of malaria does not confer protection from future attacks: individuals who have had malaria should take effective anti-mosquito precautions and chemoprophylaxis during future visits to endemic areas.

Delayed-onset hemolytic anemia in patients with travel-associated severe malaria treated with artesunate, France, 2011-2013

Artesunate is the most effective treatment for severe malaria. However, delayed-onset hemolytic anemia has been observed in ≈20% of travelers who receive artesunate, ≈60% of whom require transfusion. This finding could discourage physicians from using artesunate. We prospectively evaluated a cohort of 123 patients in France who had severe imported malaria that was treated with artesunate; our evaluation focused on outcome, adverse events, and postartesunate delayed-onset hemolysis (PADH). Of the 123 patients, 6 (5%) died. Overall, 97 adverse events occurred. Among the 78 patients who received follow-up for >8 days after treatment initiation, 76 (97%) had anemia, and 21 (27%) of the 78 cases were recorded as PADH. The median drop in hemoglobin levels was 1.3 g/dL; 15% of patients with PADH had hemoglobin levels of <7 g/dL, and 1 required transfusion. Despite the high incidence of PADH, the resulting anemia remained mild in 85% of cases. This reassuring result confirms the safety and therapeutic benefit of artesunate.

Feasibility and acceptability of injectable artesunate for the treatment of severe malaria in the Democratic Republic of Congo

Background

The Democratic Republic of the Congo (DRC) changed its national policy for the treatment of severe malaria in both children and adults in 2012 from intravenous quinine to injectable artesunate. The country is now planning to deploy nationwide injectable artesunate as the preferred treatment for the management of severe malaria. To support this process, the feasibility and acceptability of the use of injectable artesunate in the context of the DRC was assessed, from the perspective of both health care providers and patients/caretakers.

Methods

Questionnaires and observations were used to collect information from health care providers and patients/caretakers in eight health facilities in the Province of Kinshasa and in the Province of Bas-Congo.

Results

A total of 31 health care providers and 134 patients/care takers were interviewed. Seventy five percent (75 %) of health care providers found it less difficult to prepare injectable artesunate compared to quinine. None of them encountered problems during preparation and administration of injectable artesunate. The large majority of care providers (93 %) and patients/caretakers (93 %) answered that injectable artesunate took less time than quinine to cure the symptoms of the patients. 26 (84 %) health care providers reported that the personnel workload had diminished with the use of injectable artesunate. 7 (22.6 %) health workers reported adverse drug reactions, of which a decrease in the haemoglobin rate was the most common (71.4 %). All care providers and the vast majority of patients/caretakers (96 %, N = 128) were either satisfied or very satisfied with injectable artesunate.

Conclusions

These findings show that the use of injectable artesunate for the treatment of severe malaria is feasible and acceptable in the context of DRC, with appropriate training of care providers. Both care providers and patients/caretakers perceived injectable artesunate to be effective and safe, thus promoting acceptability.

Intramuscular Artesunate for Severe Malaria in African Children: A Multicenter Randomized Controlled Trial

BACKGROUND

Current artesunate (ARS) regimens for severe malaria are complex. Once daily intramuscular (i.m.) injection for 3 d would be simpler and more appropriate for remote health facilities than the current WHO-recommended regimen of five intravenous (i.v.) or i.m. injections over 4 d. We compared both a three-dose i.m. and a three-dose i.v. parenteral ARS regimen with the standard five-dose regimen using a non-inferiority design (with non-inferiority margins of 10%).

METHODS AND FINDINGS

This randomized controlled trial included children (0.5-10 y) with severe malaria at seven sites in five African countries to assess whether the efficacy of simplified three-dose regimens is non-inferior to a five-dose regimen. We randomly allocated 1,047 children to receive a total dose of 12 mg/kg ARS as either a control regimen of five i.m. injections of 2.4 mg/kg (at 0, 12, 24, 48, and 72 h) (n = 348) or three injections of 4 mg/kg (at 0, 24, and 48 h) either i.m. (n = 348) or i.v. (n = 351), both of which were the intervention arms. The primary endpoint was the proportion of children with ≥ 99% reduction in parasitemia at 24 h from admission values, measured by microscopists who were blinded to the group allocations. Primary analysis was performed on the per-protocol population, which was 96% of the intention-to-treat population. Secondary analyses included an analysis of host and parasite genotypes as risks for prolongation of parasite clearance kinetics, measured every 6 h, and a Kaplan-Meier analysis to compare parasite clearance kinetics between treatment groups. A post hoc analysis was performed for delayed anemia, defined as hemoglobin ≤ 7 g/dl 7 d or more after admission. The per-protocol population was 1,002 children (five-dose i.m.: n = 331; three-dose i.m.: n = 338; three-dose i.v.: n = 333); 139 participants were lost to follow-up. In the three-dose i.m. arm, 265/338 (78%) children had a ≥ 99% reduction in parasitemia at 24 h compared to 263/331 (79%) receiving the five-dose i.m. regimen, showing non-inferiority of the simplified three-dose regimen to the conventional five-dose regimen (95% CI -7, 5; p = 0.02). In the three-dose i.v. arm, 246/333 (74%) children had ≥ 99% reduction in parasitemia at 24 h; hence, non-inferiority of this regimen to the five-dose control regimen was not shown (95% CI -12, 1; p = 0.24). Delayed parasite clearance was associated with the N86YPfmdr1 genotype. In a post hoc analysis, 192/885 (22%) children developed delayed anemia, an adverse event associated with increased leukocyte counts. There was no observed difference in delayed anemia between treatment arms. A potential limitation of the study is its open-label design, although the primary outcome measures were assessed in a blinded manner.

CONCLUSIONS

A simplified three-dose i.m. regimen for severe malaria in African children is non-inferior to the more complex WHO-recommended regimen. Parenteral ARS is associated with a risk of delayed anemia in African children.

TRIAL REGISTRATION

Pan African Clinical Trials Registry PACTR201102000277177.

Temporal changes in haematocrit following artemisinin-based combination treatments of uncomplicated falciparum malaria in children

Background

Artemisinin-based combination treatments (ACTs) or intravenous artesunate are used in over 100 countries for uncomplicated or severe falciparum malaria. Although intravenous artesunate may cause delayed haemolytic anaemia, there is little evaluation of the temporal changes in haematocrit following ACTs.

Methods

Clinical and parasitological parameters were measured before and following treatment of uncomplicated falciparum malaria in children with artesunate-amodiaquine (AA) or artemether-lumefantrine (AL) over 6-weeks. Changes in haematocrit were characterized in individual patients based on a haematocrit <30 % or ≥30 % before and following treatment. Kinetics of the deficit in haematocrit from <30 % until attainment of ≥30 % were estimated by a non-compartment model.

Results

In 248 of 1180 children eligible for evaluation, common temporal patterns were: no change or increase in haematocrit from ≥ 30 % [50 % of patients], haematocrit >30 % at presentation declining to <30 % within 2 weeks (early monophasic fall) [19 % of patients], and haematocrit <30 % at presentation increasing to ≥ 30 % [23 % of patients]. Haematocrit >30 % at presentation declining to <30 %, 3–5 weeks later (late monophasic fall) occurred in 7 children (3 %). Fall in haematocrit ≥5 units following treatment occurred in 57 children [23 %] between 14 and 28 days after treatment began. Baseline parasitaemia and proportion with > 100,000μL^-1 asexual forms were significantly higher in children with ≥5 units compared to <5 units fall in haematocrit 21 or 28 days after treatment began. Irrespective of pattern, declines in haematocrit deficit from <30 % were mono-exponential, with similar half-times for AA- and AL-treated children (1.32 d versus 1.14 d). Anaemia half-time correlated significantly positively with anaemia recovery time in the same patients (r = 0.55, P < 0.0001). Bland-Altman analysis of 9 or 10 multiples of anaemia half-time and anaemia recovery times showed narrow limit of agreement with insignificant biases (P = 0.19 or 0.63, respectively).

Conclusions

In uncomplicated falciparum malaria, increases or falls in haematocrit are common following ACTs. Falls in haematocrit ≥ 5 units are common and may or may not result in early or late anaemia. In children who recovered from acute falciparum malaria-associated anaemia following ACTs, decline in haematocrit deficit is mono-exponential.

Trials registration

Pan African Clinical Trial Registry PACTR201508001188143, 3 July 2015; PACTR201508001191898, 7 July 2015 http://www.pactr.org.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1219-y) contains supplementary material, which is available to authorized users.