Postartesunate delayed hemolysis is a predictable event related to the lifesaving effect of artemisinins

Failure of artemether-lumefantrine therapy in travellers returning to Belgium with Plasmodium falciparum malaria: an observational case series with genomic analysis

BACKGROUND

Failure of artemisinin-based combination therapy is increasingly reported in patients with Plasmodium falciparum malaria in sub-Saharan Africa. We aimed to describe the clinical and genomic characteristics of recent cases of P. falciparum malaria failing artemether-lumefantrine in Belgium.

METHODS

Travel-related cases of malaria confirmed at the national reference laboratory of the Institute of Tropical Medicine, Antwerp, Belgium, were reviewed. All cases for which attending clinicians reported persistence (beyond Day 3 post-treatment initiation, i.e. early failure) or recrudescence (from Day 7 to 42, i.e. late failure) of P. falciparum parasites despite adequate drug intake were analysed. Both initial and persistent/recurrent samples were submitted to next generation sequencing to investigate resistance-conferring mutations.

RESULTS

From July 2022 to June 2023, eight P. falciparum cases of failure with artemether-lumefantrine therapy were reported (early failure = 1; late failure = 7). All travellers were returning from sub-Saharan Africa, most (6/8) after a trip to visit friends and relatives. PfKelch13 (PF3D7_1343700) mutations associated with resistance to artemisinin were found in two travellers returning from East Africa, including the validated marker R561H in the patient with early failure and the candidate marker A675V in a patient with late failure. Additional mutations were detected that could contribute to decreased susceptibility to artemisinin in another three cases, lumefantrine in six cases and proguanil in all eight participants. Various regimens were used to treat the persistent/recrudescent cases, with favourable outcome.

CONCLUSION

Within a 12-month period, we investigated eight travellers returning from sub-Saharan Africa with P. falciparum malaria and in whom artemether-lumefantrine failure was documented. Mutations conferring resistance to antimalarials were found in all analysed blood samples, especially against lumefantrine and proguanil, but also artemisinin. There is a pressing need for systematic genomic surveillance of resistance to antimalarials in international travellers with P. falciparum malaria, especially those experiencing treatment failure.

Nine years of imported malaria in a teaching hospital in Belgium: Demographics, clinical characteristics, and outcomes

BACKGROUND

Imported malaria is often misdiagnosed due to the aspecific symptoms and lack of familiarity among clinicians. This study aims to evaluate a decade-long trend of imported malaria cases in a Belgian teaching hospital by analyzing demographics, clinical characteristics, and outcomes.

METHODS

Medical records of 223 patients with confirmed malaria diagnoses between 2010 and 2019 were analyzed.

RESULTS

Most patients were male (63.2%), aged 18-65 years (77.1%), and visiting friends or relatives (40.8%). Central Africa was the most common travel destination (54.3%), and 63.7% did not take prophylaxis. Symptoms were flu-like, with fever (91.9%) being most prevalent. P. falciparum was identified in 88.3% of cases. A high proportion of severe cases (41.7%) and a low mortality rate (0.9%) were recorded. A severe form of the disease is associated with a more extended hospital stay than uncomplicated form (median of 5 vs. 4 days, p < 0.001). Thirty-five-point five percent [33/93] of patients with severe malaria have had a previous malaria infection compared to 50.8% [66/130] of uncomplicated patients (p= 0.013) wich was statistically significant.

CONCLUSION

Malaria disproportionately affects VFRs traveling to Central Africa, and flu-like symptoms should raise suspicion. Prophylaxis is essential to prevent the disease, and early diagnosis is critical for effective management. A severe form of the disease is associated with a more extended hospital stay than uncomplicated form and people with a previous history of malaria have a less severe disease.

Retention of uninfected red blood cells causing congestive splenomegaly is the major mechanism of anemia in malaria

Splenomegaly frequently occurs in patients with Plasmodium falciparum (Pf) or P. vivax (Pv) malarial anemia, but mechanisms underlying this co-occurrence are unclear. In malaria-endemic Papua, Indonesia, we prospectively analyzed red blood cell (RBC) concentrations in the spleen and spleen-mimetic retention in 37 subjects splenectomized for trauma or hyperreactive splenomegaly, most of whom were infected with Plasmodium. Splenomegaly (median 357 g [range: 80-1918 g]) was correlated positively with the proportion of red-pulp on histological sections (median 88.1% [range: 74%-99.4%]; r = .59, p = .0003) and correlated negatively with the proportion of white-pulp (median 8.3% [range: 0.4%-22.9%]; r = -.50, p = .002). The number of RBC per microscopic field (>95% uninfected) was correlated positively with spleen weight in both Pf-infected (r = .73; p = .017) and Pv-infected spleens (r = .94; p = .006). The median estimated proportion of total-body RBCs retained in Pf-infected spleens was 8.2% (range: 1.0%-33.6%), significantly higher than in Pv-infected (2.6% [range: 0.6%-23.8%]; p = .015) and PCR-negative subjects (2.5% [range: 1.0%-3.3%]; p = .006). Retained RBCs accounted for over half of circulating RBC loss seen in Pf infections. The proportion of total-body RBC retained in Pf- and Pv-infected spleens correlated negatively with hemoglobin concentrations (r = -.56, p = .0003), hematocrit (r = -.58, p = .0002), and circulating RBC counts (r = -.56, p = .0003). Splenic CD71-positive reticulocyte concentrations correlated with spleen weight in Pf (r = 1.0; p = .003). Retention rates of peripheral and splenic RBCs were correlated negatively with circulating RBC counts (r = -.69, p = .07 and r = -.83, p = .008, respectively). In conclusion, retention of mostly uninfected RBC in the spleen, leading to marked congestion of the red-pulp, was associated with splenomegaly and is the major mechanism of anemia in subjects infected with Plasmodium, particularly Pf.

Reduced splenic function can mimic artemisinin resistance in severe malaria

We describe severe post-treatment episodes that complicate Plasmodium falciparum malaria in patients with hyposplenism, characterized by prolonged circulation of red cells containing dead parasites (hearse red cells), persistent or recurrent fever, profound anaemia, and inflammation. Asplenia-related Post-antimalarial Inflammation & Hemolysis (APIH) mimics concomitant infection and parasite resistance to drugs.

Intra-erythrocytic vacuoles in asplenic patients: elusive genesis and original clearance of unique organelles

The spleen plays a dual role of immune response and the filtration of red blood cells (RBC), the latter function being performed within the unique microcirculatory architecture of the red pulp. The red pulp filters and eliminates senescent and pathological RBC and can expell intra-erythrocytic rigid bodies through the so-called pitting mechanism. The loss of splenic function increases the risk of infections, thromboembolism, and hematological malignancies. However, current diagnostic tests such as quantification of Howell-Jolly Bodies and splenic scintigraphy lack sensitivity or are logistically demanding. Although not widely available in medical practice, the quantification of RBC containing vacuoles, i.e., pocked RBC, is a highly sensitive and specific marker for hyposplenism. The peripheral blood of hypo/asplenic individuals contains up to 80% RBC with vacuoles, whereas these pocked RBC account for less than 4% of RBC in healthy subjects. Despite their value as a spleen function test, intraerythrocytic vacuoles have received relatively limited attention so far, and little is known about their origin, content, and clearance. We provide an overview of the current knowledge regarding possible origins and mechanisms of elimination, as well as the potential function of these unique and original organelles observed in otherwise "empty" mature RBC. We highlight the need for further research on pocked RBC, particularly regarding their potential function and specific markers for easy counting and sorting, which are prerequisites for functional studies and wider application in medical practice.

Pathogenicity and virulence of malaria: Sticky problems and tricky solutions

Infections with Plasmodium falciparum and Plasmodium vivax cause over 600,000 deaths each year, concentrated in Africa and in young children, but much of the world's population remain at risk of infection. In this article, we review the latest developments in the immunogenicity and pathogenesis of malaria, with a particular focus on P. falciparum, the leading malaria killer. Pathogenic factors include parasite-derived toxins and variant surface antigens on infected erythrocytes that mediate sequestration in the deep vasculature. Host response to parasite toxins and to variant antigens is an important determinant of disease severity. Understanding how parasites sequester, and how antibody to variant antigens could prevent sequestration, may lead to new approaches to treat and prevent disease. Difficulties in malaria diagnosis, drug resistance, and specific challenges of treating P. vivax pose challenges to malaria elimination, but vaccines and other preventive strategies may offer improved disease control.

Favorable outcome without corticosteroids during post-artesunate delayed hemolysis with positive direct antiglobulin test in severe imported Plasmodium falciparum malaria, France

OBJECTIVES

Positive direct antiglobulin tests (DATs) have been reported in cases of post-artesunate delayed hemolysis (PADH), but the causal role of auto-immune hemolysis remains unclear. We aimed to analyze a cohort of patients with PADH and DAT during severe malaria.

METHODS

We describe PADH and DAT results in a 7-year multi-center retrospective cohort of patients receiving artesunate for severe imported malaria.

RESULTS

Of 337 patients treated with artesunate, 46 (13.6%) had at least one DAT result within 30 days of treatment initiation, and 25/46 (54.3%) had at least one positive DAT. Among 40 patients with available data, 17 (42.5%) experienced PADH. Patient characteristics were similar for patients with a positive or negative DAT, and DAT positivity was not associated with PADH occurrence (P = 0.36). Among patients, 5/13 (38.5%) with a positive DAT after day 7 experienced PADH, compared to 10/13 (76.9%) of those with a negative DAT after day 7 (P = 0.11). Overall, 41% of patients required blood transfusions, and outcome was favorable without corticosteroids, even in cases of PADH.

CONCLUSIONS

DAT does not appear to be a marker of PADH, but rather an indirect marker of an immune-mediated mechanism. DAT positivity should not lead to the administration of systemic corticosteroids during PADH.

Intravenous Artesunate Treatment of Severe Malaria in a Patient With Systemic Lupus Erythematosus: A Case of Post-Artesunate Delayed Hemolysis

Systemic lupus erythematosus (SLE) is an autoimmune condition linked to multi-organ damage, and its correlation with malaria has been theorized. This case report details a 14-year-old Sudanese girl diagnosed with SLE and severe malaria who experienced hemolytic anemia following intravenous artesunate treatment. Intravenous artesunate was administered as the recommended treatment for severe malaria for one week and led to prolonged hemolysis with low hemoglobin levels and elevated lactate dehydrogenase activity; over three weeks, the hemolysis gradually subsided. This case highlights the need to consider post-artesunate (or artemisinin) delayed hemolysis (PADH) as a potential complication among patients receiving artemisinin derivatives for malaria treatment, thus necessitating enhanced surveillance strategies and further investigation of its mechanisms to optimize clinical practice and patient outcomes in this population.

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.

The sting in the tail of severe falciparum malaria: Post-artesunate delayed haemolysis

Post-artesunate delayed haemolysis (PADH) is thought to occur because of delayed clearance of previously malarial infected erythrocytes spared by ‘pitting’ during treatment. We report a case of PADH following the treatment of Plasmodium (P.) falciparum malaria (32% parasitaemia), with a positive direct antiglobulin (DAT) test, suggesting an immune mechanism.

Altered Subpopulations of Red Blood Cells and Post-treatment Anemia in Malaria

In acute malaria, the bulk of erythrocyte loss occurs after therapy, with a nadir of hemoglobin generally observed 3–7 days after treatment. The fine mechanisms leading to this early post-treatment anemia are still elusive. We explored pathological changes in RBC subpopulations by quantifying biochemical and mechanical alterations during severe malaria treated with artemisinin derivatives, a drug family that induce “pitting” in the spleen. In this study, the hemoglobin concentration dropped by 1.93 G/dl during therapy. During the same period, iRBC accounting for 6.12% of all RBC before therapy (BT) were replaced by pitted-RBC, accounting for 5.33% of RBC after therapy (AT). RBC loss was thus of 15.9%, of which only a minor part was due to the loss of iRBC or pitted-RBC. When comparing RBC BT and AT to normal controls, lipidomics revealed an increase in the cholesterol/phosphatidylethanolamine ratio (0.17 versus 0.24, p < 0.001) and cholesterol/phosphatidylinositol ratio (0.36 versus 0.67, p = 0.001). Using ektacytometry, we observed a reduced deformability of circulating RBC, similar BT and AT, compared to health control donors. The mean Elongation Index at 1.69Pa was 0.24 BT and 0.23 AT vs. 0.28 in controls (p < 0.0001). At 30Pa EI was 0.56 BT and 0.56 AT vs. 0.60 in controls (p < 0.001). The retention rate (rr) of RBC subpopulations in spleen-mimetic microsphere layers was higher for iRBC (rr = 20% p = 0.0033) and pitted-RBC (rr = 19%, p = 0.0031) than for healthy RBC (0.12%). Somewhat surprisingly, the post-treatment anemia in malaria results from the elimination of RBC that were never infected.

Recent Advances in the Therapeutic Efficacy of Artesunate

Artesunate, a semisynthetic artemisinin derivative, is well-known and used as the first-line drug for treating malaria. Apart from treating malaria, artesunate has also been found to have biological activity against a variety of cancers and viruses. It also exhibits antidiabetic, anti-inflammatory, anti-atherosclerosis, immunosuppressive activities, etc. During its administration, artesunate can be loaded in liposomes, alone or in combination with other therapeutic agents. Administration routes include intragastrical, intravenous, oral, and parenteral. The biological activity of artesunate is based on its ability to regulate some biological pathways. This manuscript reports a critical review of the recent advances in the therapeutic efficacy of artesunate.

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.

Case Report: Autoimmune Hemolysis Anemia After Dihydroartemisinin and Piperaquine for Uncomplicated Plasmodium falciparum Malaria

Malaria is still an endemic disease in Africa, with many imported cases in Europe. The standard treatment is intravenous artesunate for severe malaria and oral artemisinin-based combination therapy (ACT) for uncomplicated malaria. Delayed hemolytic anemia (DHA) after intravenous artesunate has been extensively described, and guidelines recommend biological monitoring until 1 month after the end of the treatment. A link with an autoimmune process is still unsure. Nevertheless, cases with positive direct antiglobulin test (DAT) have been reported. Conversely, DHA is not recognized as an adverse effect of oral ACT. Previously, only few cases of DHA occurring after oral ACT without intravenous artesunate administration have been reported. We report the case of a 42-year-old man returning from Togo. He was treated with dihydroartemisinin/piperaquine combination for uncomplicated Plasmodium falciparum malaria, with low parasitemia. Nine days after the end of the treatment, the patient developed hemolytic anemia with positive DAT. Eventually, the patient recovered after corticotherapy. After excluding common causes of autoimmune hemolytic anemia, we considered that dihydroartemisinin/piperaquine treatment was involved in this side effect.

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.

Post-artesunate delayed hemolysis after treatment of malaria with intravenous artesunate: A case study

Delayed hemolysis is an uncommon reaction to intravenous artesunate for the treatment of severe malaria. We report a case of a patient who developed severe malaria after initial improper treatment, thus requiring IV artesunate therapy. Delayed hemolytic anemia then occurred and was monitored for weeks after completion of treatment.

Haematological response in experimental human Plasmodium falciparum and Plasmodium vivax malaria

Background

Malaria-associated anaemia, arising from symptomatic, asymptomatic and submicroscopic infections, is a significant cause of morbidity worldwide. Induced blood stage malaria volunteer infection studies (IBSM-VIS) provide a unique opportunity to evaluate the haematological response to early Plasmodium falciparum and Plasmodium vivax infection.

Methods

This study was an analysis of the haemoglobin, red cell counts, and parasitaemia data from 315 participants enrolled in IBSM-VIS between 2012 and 2019, including 269 participants inoculated with the 3D7 strain of P. falciparum (Pf3D7), 15 with an artemisinin-resistant P. falciparum strain (PfK13) and 46 with P. vivax. Factors associated with the fractional fall in haemoglobin (Hb-FF) were evaluated, and the malaria-attributable erythrocyte loss after accounting for phlebotomy-related losses was estimated. The relative contribution of parasitized erythrocytes to the malaria-attributable erythrocyte loss was also estimated.

Results

The median peak parasitaemia prior to treatment was 10,277 parasites/ml (IQR 3566–27,815), 71,427 parasites/ml [IQR 33,236–180,213], and 34,840 parasites/ml (IQR 13,302–77,064) in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. The median Hb-FF was 10.3% (IQR 7.8–13.3), 14.8% (IQR 11.8–15.9) and 11.7% (IQR 8.9–14.5) in those inoculated with Pf3D7, PfK13 and P. vivax, respectively, with the haemoglobin nadir occurring a median 12 (IQR 5–21), 15 (IQR 7–22), and 8 (IQR 7–15) days following inoculation. In participants inoculated with P. falciparum, recrudescence was associated with a greater Hb-FF, while in those with P. vivax, the Hb-FF was associated with a higher pre-treatment parasitaemia and later day of anti-malarial treatment. After accounting for phlebotomy-related blood losses, the estimated Hb-FF was 4.1% (IQR 3.1–5.3), 7.2% (IQR 5.8–7.8), and 4.9% (IQR 3.7–6.1) in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. Parasitized erythrocytes were estimated to account for 0.015% (IQR 0.006–0.06), 0.128% (IQR 0.068–0.616) and 0.022% (IQR 0.008–0.082) of the malaria-attributable erythrocyte loss in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively.

Conclusion

Early experimental P. falciparum and P. vivax infection resulted in a small but significant fall in haemoglobin despite parasitaemia only just at the level of microscopic detection. Loss of parasitized erythrocytes accounted for < 0.2% of the total malaria-attributable haemoglobin loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04003-7.

Safety and Effectiveness of Intravenous Artesunate for Treatment of Severe Malaria in the United States-April 2019 Through December 2020

BACKGROUND

Severe malaria can be deadly and requires treatment with intravenous artesunate (IVAS). The Centers for Disease Control and Prevention provided IVAS starting 1 April 2019 for all patients with severe malaria in the United States. This study describes the safety and effectiveness of IVAS in these patients.

METHODS

Patients meeting criteria for severe malaria April 2019-December 2020 who received IVAS were included. Demographic, clinical, laboratory, adverse event, and outcome information were collected. Clinical presentation, time to reach 1% and 0% parasitemia, adverse events, and death were described using proportions, medians, interquartile range (IQR), and tests of significance for differences in proportions.

RESULTS

Of 280 patients included, the majority were male (61.4%), Black (75.0%), with a median age of 35 years (IQR: 15.8-53.9). Most had Plasmodium falciparum (83.6%) with median parasitemia of 8.0% (IQR: 4.6-13.2). Of 170 patients with information, 159 (93.5%) reached ≤1% parasitemia by the third IVAS dose with a median time of 17.6 hours (IQR: 10.8-28.8), and 0% parasitemia in a median of 37.2 hours (IQR 27.2-55.2). Patients with parasite densities >10% and those requiring adjunct therapy had significantly higher parasite clearance times. Adverse events associated with IVAS were reported in 4.8% (n = 13 of 271). Eight patients had post-artesunate delayed hemolysis that resolved. There were 5 (1.8%) deaths, all attributable to severe malaria.

CONCLUSIONS

IVAS is a safe and effective drug for the treatment of severe malaria in the United States; timely administration can be lifesaving.

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.

Intravenous Artesunate for the Treatment of Severe Imported Malaria: Implementation, Efficacy, and Safety in 1391 Patients

BACKGROUND

Intravenous artesunate is the World Health Organization-recommended first-line treatment for severe malaria worldwide, but it is still not fully licensed in Europe. Observational studies documenting its safety and efficacy in imported malaria are thus essential.

METHODS

We prospectively collected clinical and epidemiological features of 1391 artesunate-treated patients among 110 participant centers during the first 7 years (2011-2017) of a national program implemented by the French Drug Agency.

RESULTS

Artesunate became the most frequent treatment for severe malaria in France, rising from 9.9% in 2011 to 71.4% in 2017. Mortality was estimated at 4.1%. Treatment failure was recorded in 27 patients, but mutations in the Kelch-13 gene were not observed. Main reported adverse events (AEs) were anemia (136 cases), cardiac events (24, including 20 episodes of conduction disorders and/or arrhythmia), and liver enzyme elevation (23). Mortality and AEs were similar in the general population and in people with human immunodeficiency virus, who were overweight, or were pregnant, but the only pregnant woman treated in the first trimester experimented a hemorrhagic miscarriage. The incidence of post-artesunate-delayed hemolysis (PADH) was 42.8% when specifically assessed in a 98-patient subgroup, but was not associated with fatal outcomes or sequelae. PADH was twice as frequent in patients of European compared with African origin.

CONCLUSIONS

Artesunate was rapidly deployed and displayed a robust clinical benefit in patients with severe imported malaria, despite a high frequency of mild to moderate PADH. Further explorations in the context of importation should assess outcomes during the first trimester of pregnancy and collect rare but potentially severe cardiac AEs.

Pitting of malaria parasites in microfluidic devices mimicking spleen interendothelial slits

The spleen is a hematopoietic organ that participates in cellular and humoral immunity. It also serves as a quality control mechanism for removing senescent and/or poorly deformable red blood cells (RBCs) from circulation. Pitting is a specialized process by which the spleen extracts particles, including malaria parasites, from within circulating RBCs during their passage through the interendothelial slits (IES) in the splenic cords. To study this physiological function in vitro, we have developed two microfluidic devices modeling the IES, according to the hypothesis that at a certain range of mechanical stress on the RBC, regulated through both slit size and blood flow, would force it undergo the pitting process without affecting the cell integrity. To prove its functionality in replicating pitting of malaria parasites, we have performed a characterization of P. falciparum-infected RBCs (P.f.-RBCs) after their passage through the devices, determining hemolysis and the proportion of once-infected RBCs (O-iRBCs), defined by the presence of a parasite antigen and absence of DAPI staining of parasite DNA using a flow cytometry-based approach. The passage of P.f.-RBCs through the devices at the physiological flow rate did not affect cell integrity and resulted in an increase of the frequency of O-iRBCs. Both microfluidic device models were capable to replicate the pitting of P.f.-RBCs ex vivo by means of mechanical constraints without cellular involvement, shedding new insights on the role of the spleen in the pathophysiology of malaria.

Clinical management of Plasmodium knowlesi malaria

The zoonotic parasite Plasmodium knowlesi has emerged as an important cause of human malaria in parts of Southeast Asia. The parasite is indistinguishable by microscopy from the more benign P. malariae, but can result in high parasitaemias with multiorgan failure, and deaths have been reported. Recognition of severe knowlesi malaria, and prompt initiation of effective therapy is therefore essential to prevent adverse outcomes. Here we review all studies reporting treatment of uncomplicated and severe knowlesi malaria. We report that although chloroquine is effective for the treatment of uncomplicated knowlesi malaria, artemisinin combination treatment is associated with faster parasite clearance times and lower rates of anaemia during follow-up, and should be considered the treatment of choice, particularly given the risk of administering chloroquine to drug-resistant P. vivax or P. falciparum misdiagnosed as P. knowlesi malaria in co-endemic areas. For severe knowlesi malaria, intravenous artesunate has been shown to be highly effective and associated with reduced case-fatality rates, and should be commenced without delay. Regular paracetamol may also be considered for patients with severe knowlesi malaria or for those with acute kidney injury, to attenuate the renal damage resulting from haemolysis-induced lipid peroxidation.

Artesunate-induced hemolysis in severe complicated malaria - A diagnostic challenge: A case report and literature review of anemia in malaria

Malaria infection, which results due to the parasitic protozoan Plasmodium, has several known etiologies of hemolytic anemia as a possible complication in cases such as concurrent G6PD deficiency, severe parasitemia, or use of parenteral antimalarials. Although artemisinin-based antimalarial therapies are generally well-tolerated, several cases of severe post-artemisinin delayed hemolysis (PADH) have been recently reported, which present a diagnostic challenge, and affect morbidity and mortality in patients with malarial infection. We highlight the case of a young lady with Plasmodium falciparum severe parasitemia who developed hemolytic anemia after parenteral artesunate therapy.

Analysis of spleen histopathology, splenocyte composition and haematological parameters in four strains of mice infected with Plasmodium berghei K173

BACKGROUND

Malaria is a fatal disease that presents clinically as a continuum of symptoms and severity, which are determined by complex host-parasite interactions. Clearance of infection is believed to be accomplished by the spleen and mononuclear phagocytic system (MPS), independent of artemisinin treatment. The spleen filters infected red blood cells (RBCs) from circulation through immune-mediated recognition of the infected RBCs followed by phagocytosis. This study evaluated the tolerance of four different strains of mice to Plasmodium berghei strain K173 (P. berghei K173), and the differences in the role of the spleen in controlling P. berghei K173 infection.

METHODS

Using different strains of mice (C57BL/6, BALB/C, ICR, and KM mice) infected with P. berghei K173, the mechanisms leading to splenomegaly, histopathology, splenocyte activation and proliferation, and their relationship to the control of parasitaemia and host mortality were examined and evaluated.

RESULTS

Survival time of mice infected with P. berghei K173 varied, although the infection was uniformly lethal. Mice of the C57BL/6 strain were the most resistant, while mice of the strain ICR were the most susceptible. BALB/c and KM mice were intermediate. In the course of P. berghei K173 infection, all infected mice experienced significant splenomegaly. Parasites were observed in the red pulp at 3 days post infection (dpi) in all animals. All spleens retained late trophozoite stages as well as a fraction of earlier ring-stage parasites. The percentages of macrophages in infected C57BL/6 and KM mice were higher than uninfected mice on 8 dpi. Spleens of infected ICR and KM mice exhibited structural disorganization and remodelling. Furthermore, parasitaemia was significantly higher in KM versus C57BL/6 mice at 8 dpi. The percentages of macrophages in ICR infected mice were lower than uninfected mice, and the parasitaemia was higher than other strains.

CONCLUSIONS

The results presented here demonstrate the rate of splenic mechanical filtration and that splenic macrophages are the predominant roles in controlling an individual's total parasite burden. This can influence the pathogenesis of malaria. Finally, different genetic backgrounds of mice have different splenic mechanisms for controlling malaria infection.

Systematic analysis of direct antiglobulin test results in post-artesunate delayed haemolysis

Background

Post-artesunate delayed haemolysis (PADH) is common after severe malaria episodes. PADH is related to the “pitting” phenomenon and the synchronous delayed clearance of once-infected erythrocytes, initially spared during treatment. However, direct antiglobulin test (DAT) positivity has been reported in several PADH cases, suggesting a contribution of immune-mediated erythrocyte clearance. The aim of the present study was to compare clinical features of cases presenting a positive or negative DAT.

Methods

Articles reporting clinical data of patients diagnosed with PADH, for whom DAT had been performed, were collected from PubMed database. Data retrieved from single patients were extracted and univariate analysis was performed in order to identify features potentially related to DAT results and steroids use.

Results

Twenty-two studies reporting 39 PADH cases were included: median baseline parasitaemia was 20.8% (IQR: 11.2–30) and DAT was positive in 17 cases (45.5%). Compared to DAT-negative individuals, DAT-positive patients were older (49.5 vs 31; p = 0.01), had a higher baseline parasitaemia (27% vs 17%; p = 0.03) and were more commonly treated with systemic steroids (11 vs 3 patients, p = 0.002). Depth and kinetics of delayed anaemia were not associated with DAT positivity.

Conclusions

In this case series, almost half of the patients affected by PADH had a positive DAT. An obvious difference between the clinical courses of patients presenting with a positive or negative DAT was lacking. This observation suggests that DAT result may not be indicative of a pathogenic role of anti-erythrocytes antibodies in patients affected by PADH, but it may be rather a marker of immune activation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03735-w.

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.

Repurposing Anti-Malaria Phytomedicine Artemisinin as a COVID-19 Drug

Artemisinin is an anti-inflammatory phytomedicine with broad-spectrum antiviral activity. Artemisinin and its antimalarial properties were discovered by the Chinese scientist Tu Youyu, who became one of the laureates of the 2015 Nobel Prize in Physiology or Medicine for this breakthrough in tropical medicine. It is a commonly used anti-malaria drug. Artemisinin has recently been repurposed as a potential COVID-19 drug. Its documented anti-SARS-CoV-2 activity has been attributed to its ability to inhibit spike-protein mediated and TGF-β-dependent early steps in the infection process as well as its ability to disrupt the post-entry intracellular events of the SARS-CoV-2 infection cycle required for viral replication. In addition, Artemisinin has anti-inflammatory activity and reduces the systemic levels of inflammatory cytokines that contribute to cytokine storm and inflammatory organ injury in high-risk COVID-19 patients. We postulate that Artemisinin may prevent the worsening of the health condition of patients with mild-moderate COVID-19 when administered early in the course of their disease.

[Abnormal urine color assessment: The urine wheel]

Looking at the urine for diagnostic purposes, once performed by ancient Egyptians, can still provide some valuable clues in modern medicine. Several diseases have been named after their associated urine color and this underlines the clinical value of visual urine inspection: blue diaper disease, purple urine bag syndrome, black urine disease or porphyria. Abnormal urine color could be challenging for the clinician: it may reveal neoplastic disease (urologic cancer; melanoma), cell lysis (rhabdomyolysis; hemolysis), infection (lymphatic filariasis; malaria), enzyme deficiency (porphyria; alkaptonuria), medication or food intake. In this article, we present the diagnostic approach, the mechanisms involved and the main causes of abnormal urine color.

Acute kidney injury secondary to severe delayed haemolysis in intravenous artesunate use for severe malaria

The use of artemisinin derivatives has been recommended by the WHO guidelines in malaria treatment largely due to its rapid parasite clearance and safety profile. This case report details the development of delayed haemolysis and subsequent severe acute kidney injury (AKI) 13 days after commencing intravenous artesunate treatment for malaria in an Australian returned traveller. Delayed haemolysis may be an under-recognised complication following artesunate use and if severe, can be complicated by AKI. Therefore, close patient follow-up following treatment is required to ensure prompt recognition of this phenomenon.

Propensity Score Analysis of Artesunate Versus Quinine for Severe Imported Plasmodium falciparum Malaria in France

BACKGROUND

Little is known on the use of artesunate compared with quinine for the treatment of imported malaria cases in nonendemic countries with a high level of care. Therefore, we compared the 2 treatments in terms of mortality and hospital and intensive care unit (ICU) discharge rates.

METHODS

We analyzed the cohort of all severe imported malaria patients reported to the French National Reference Center from 2011 to 2017. After controlling for differences between quinine- and artesunate-treated individuals using the inverse probability of treatment weighting method, 28-day mortality rate was compared between the groups as well as hospital and ICU discharge rates using Kaplan-Meier estimation and weighted Cox proportional hazard models.

RESULTS

Overall, 1544 patients were enrolled. Fifty patients died, 18 in the quinine group (n = 460) and 32 in the artesunate group (n = 1084), corresponding to death rates of 3.9% and 2.9%, respectively. No difference was evident between quinine and artesunate either in mortality or in hospital discharge rate, with hazard ratios (HRs) of 1.03 (95% confidence interval [CI], 0.47-2.25) and 1.12 (95% CI, 0.94-1.34), respectively. Artesunate was associated with a faster ICU discharge rate (HR, 1.18. 95% CI, 1.02-1.36).

CONCLUSIONS

In a country with a high level of care, artesunate was associated with a shorter length of stay in the ICU, which supports the actual therapeutic transition; however, no difference was found in terms of mortality or in hospital discharge rates between artesunate- and quinine-treated patients.

Could Artesunate Have a Positive Effect on the Neurological Complications Related to Infection When It Is Used in the Treatment of COVID-19?

Artesunate is a safe noncytotoxic drug with low side effects which is used in the treatment of chloroquine-resistant malaria. In addition to being an antimalarial drug, artesunate also has immunomodulatory, anticarcinogenic, and antiviral activity. There are in vivo and in vitro studies reporting that artesunate may have a positive effect on the treatment of COVID-19. Artesunate may be effective based on its effect on the anti-inflammatory activity, chloroquine-like endocytosis inhibition mechanism, and nuclear factor kappa B (NF-κB) signal pathway. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may cause neurological complications in addition to targeting the respiratory system. In this study, we have discussed the possible neuroprotective action mechanisms of artesunate. We think that systemic and intranasal topical artesunate administration may have a positive effect on neurological complications resulting from COVID-19.

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.

Increase hemoglobin level in severe malarial anemia while controlling parasitemia: A mathematical model

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine produced by immune cells; it can play a protective or deleterious role in response to pathogens. The intracellular malaria parasite secretes a similar protein, PMIF. The present paper is concerned with severe malarial anemia (SMA), where MIF suppresses the recruitment of red blood cells (RBCs) from the spleen and the bone marrow. This suppression results in a decrease of the hemoglobin (H_b) in the blood to a dangerous level. Indeed, SMA is responsible for the majority of death-related malaria cases. Artesunate is the first line of treatment of SMA; it accelerates the death of infected RBCs (iRBCs), thereby decreasing parasitemia. However, artesunate does not increase the level of H_b, and, in some cases, post-artesunate hemolytic anemia requires blood transfusion. In order to avoid this situation, we explore combining artesunate with another drug so that the H_b level is increased to healthy levels while parasitemia is still controlled. In this paper we show, by a mathematical model, that increasing the H_b levels while controlling parasitemia in malarial anemia can be done with the experimental drug Epoxyazadiradione (Epoxy) in combination with artesunate. Epoxy acts as MIF inhibitor and thus has the potential to increase the H_b level. Simulations of the model show that the two drugs compliment each other: while artesunate is primarily responsible for decreasing parasitemia, Epoxy is primarily responsible for increasing the hemoglobin level.

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.

Post-artemisinin delayed hemolysis after oral therapy for P. falciparum infection

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Post-artemisinin delayed hemolysis after oral artemisinin therapy.

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Hemolytic anemia requiring transfusion after severe malaria infection and oral artemether-lumefantrine.

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Oral artemisinin therapy can cause post-artemisinin delayed hemolysis without exposure to IV artesunate.

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Corticosteroid therapy may reduce blood transfusion burdens in post-artemisinin delayed hemolysis.

A documented side-effect of artemisinin therapy is post-artemisinin delayed hemolysis (PADH), primarily occurring after parenteral treatment for severe P. falciparum infections. PADH has been infrequently reported after oral therapy and is rarely severe enough to require hospitalization and blood transfusions. A 24 year old man was diagnosed with P. falciparum, prompting initiation of oral artemether-lumefantrine (AL). Further work-up demonstrated that he met WHO criteria for severe malaria infection on the basis of high parasitemia and his regimen was switched to intravenous quinidine and oral doxycycline. He was transitioned back to AL after 4 days and was discharged on hospital day six. Five days later, he was readmitted for hemolytic anemia. His peripheral blood was absent of malaria parasites and he was diagnosed with PADH, ultimately requiring multiple blood transfusions. Severe hemolytic anemia requiring blood transfusions after oral artemisinin therapy is rare and may be associated with higher parasite loads. This case demonstrates the importance of close reassessment and consideration of PADH in patients treated with oral therapies, particularly in the setting of severe malarial infections.

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.

Methods to Investigate the Deformability of RBC During Malaria

Despite a 30% decline in mortality since 2000, malaria still affected 219 million subjects and caused 435,000 deaths in 2017. Red blood cells (RBC) host Plasmodium parasites that cause malaria, of which Plasmodium falciparum is the most pathogenic. The deformability of RBC is markedly modified by invasion and development of P. falciparum. Surface membrane area is potentially impacted by parasite entry and development, the cytoskeleton is modified by parasite proteins and cytosol viscosity is altered by parasite metabolism. RBC hosting mature parasites (second half of the asexual erythrocytic cycle) are abnormally stiff but the main reason for their absence from the circulation is their adherence to endothelial cells, mediated by parasite proteins exposed at the infected-RBC surface. By contrast, the circulation of non-adherent rings and gametocytes, depends predominantly on deformability. Altered deformability of rings and of uninfected-RBC altered by malaria infection is an important determinant of malaria pathogenesis. It also impacts the response to antimalarial therapy. Unlike conventional antimalarials that target mature stages, currently recommended first-line artemisinin derivatives and the emerging spiroindolones act on circulating rings. Methods to investigate the deformability of RBC are therefore critical to understand the clearance of infected- and uninfected-RBC in malaria. Herein, we review the main methods to assess the deformability of P. falciparum infected-RBC, and their contribution to the understanding of how P. falciparum infection causes disease, how the parasite is transmitted and how antimalarial drugs induce parasite clearance.

Artenimol-piperaquine in children with uncomplicated imported falciparum malaria: experience from a prospective cohort

Background

Although malaria remains one of the major public health threats in inter-tropical areas, there is limited understanding of imported malaria in children by paediatricians and emergency practitioners in non-endemic countries, often resulting in misdiagnosis and inadequate treatment. Moreover, classical treatments (atovaquone-proguanil, quinine, mefloquine) are limited either by lengthy treatment courses or by side effects. Since 2010, the World Health Organization (WHO) has recommended the use of oral artemisinin-based combination therapy for the treatment of uncomplicated Plasmodium falciparum malaria worldwide. The benefits of artenimol–piperaquine in children have been validated in endemic countries but experience remains limited in cases of imported malaria.

Methods

This prospective observational study in routine paediatric care took place at the Emergency Department, Robert-Debré Hospital (Paris, France) from September 2012 to December 2014. Tolerance and efficacy of artenimol–piperaquine in children presenting with the following inclusion criteria were assessed: P. falciparum positive on thin or thick blood smear; and the absence of WHO-defined features of severity.

Results

Among 83 children included in this study, treatment with artenimol–piperaquine was successful in 82 children (98.8%). None of the adverse events were severe and all were considered mild with no significant clinical impact. This also applied to cardiological adverse events despite a significant increase of the mean post-treatment QTc interval.

Conclusion

Artenimol–piperaquine displays a satisfying efficacy and tolerance profile as a first-line treatment for children with imported uncomplicated falciparum malaria and only necessitates three once-daily oral intakes of the medication. Comparative studies versus artemether-lumefantrine or atovaquone-proguanil would be useful to confirm the results of this study.