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

Efficient One-Pot Synthesis of Novel Caffeic Acid Derivatives as Potential Antimalarials

New protocol for the preparation of the novel caffeic acid derivatives using the Wittig reaction has been applied to follow the principles of green chemistry. The compounds have been evaluated against chloroquine-sensitive and chloroquine-resistant P. falciparum strains. Their cytotoxicity to normal human dermal fibroblasts and their propensity to induce hemolysis have been also determined. Ethyl (2E)-3-(2,3,4-trihydroxyphenyl)-2-methylpropenoate has exhibited the highest antiplasmodial activity against P. falciparum strains without the cytotoxic and hemolytic effects. This derivative is significantly more potent than caffeic acid parent structure. The application of our one-step procedure has been shown to be rapid and efficient. It allows for an easy increase of input data to refine the structure-activity relationship model of caffeates as the antimalarials. The one-step approach meets the conditions of "atom economy" and eliminates hazardous materials. Water has been used as the effective medium for the Wittig reaction to avoid toxic organic solvents.

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.

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.

A comparison of the clinical, laboratory and epidemiological features of two divergent subpopulations of Plasmodium knowlesi

Plasmodium knowlesi, a simian malaria parasite responsible for all recent indigenous cases of malaria in Malaysia, infects humans throughout Southeast Asia. There are two genetically distinct subpopulations of Plasmodium knowlesi in Malaysian Borneo, one associated with long-tailed macaques (termed cluster 1) and the other with pig-tailed macaques (cluster 2). A prospective study was conducted to determine whether there were any between-subpopulation differences in clinical and laboratory features, as well as in epidemiological characteristics. Over 2 years, 420 adults admitted to Kapit Hospital, Malaysian Borneo with knowlesi malaria were studied. Infections with each subpopulation resulted in mostly uncomplicated malaria. Severe disease was observed in 35/298 (11.7%) of single cluster 1 and 8/115 (7.0%) of single cluster 2 infections (p = 0.208). There was no clinically significant difference in outcome between the two subpopulations. Cluster 1 infections were more likely to be associated with peri-domestic activities while cluster 2 were associated with interior forest activities consistent with the preferred habitats of the respective macaque hosts. Infections with both P. knowlesi subpopulations cause a wide spectrum of disease including potentially life-threatening complications, with no implications for differential patient management.

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.

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.

Serum levels of total human Tau associated with axonal damage among severe malaria patients in Central India

Tau is a microtubule-associated protein (MAP) that is abundant in the axonal part of neurons of the central nervous system. Previous studies among African children and Vietnamese adults suffering from cerebral malaria (CM) showed the pathological significance of measuring circulatory total Tau levels. A pilot investigation was carried out to better characterise neurological pathogenesis among severe malaria patients in Central India. Serum levels of total human Tau (pg/ml) were measured by ELISA following manufacturer guidelines among hospital admitted P. falciparum malaria patients classified with different degree of severity (mild malaria = MM, non-cerebral severe malaria = NCSM, cerebral malaria survivors = CM-S and cerebral malaria non-survivors = CM-NS) using WHO, 2000 definitions, including healthy controls (HC) enroled from the hospital's blood bank. Categorical and numerical variables were analysed by applying appropriate statistical test using Stata 11.0 software. A total of 139 subjects (14 HC, 25 MM, 29 NCSM, 44 CM-S and 27 CM-NS) were included in this preliminary investigation. Serum levels of total human Tau were detected in 0% HC, 4.0% MM, 20.7% NCSM, 43.2% CM-S and 48.2% CM-NS patients. Compared to MM, percent Tau detection was significantly higher among severe malaria patients (p = 0.001). Further, compared to NCSM,% Tau detection was significantly higher in CM-S patients (Chi² = 3.9, p = 0.048) & CM-NS patients (Chi² = 4.7, p = 0.030). Percent Tau detection was also significantly higher among severe malaria cases presenting with multiple complications compared to those without multiple complications (p = 0.006). ROC analysis of serum Tau levels (pg/ml) revealed a fair AUC value (0.75) to distinguish CM-NS group (but not CM-S) from NCSM group. In conclusion, serum percent detection of total human Tau is associated with axonal damage among patients with different degree of P. falciparum malaria severity in Central India.