Human cerebral malaria: 2019 mini review

Beta vulgaris Betalains Mitigate Parasitemia and Brain Oxidative Stress Induced by Plasmodium berghei in Mice

Although many drugs have been discovered to treat malaria infection, many of them face resistance from the host's body with long-term use. Therefore, this study aimed to evaluate the activity of betalains (from Beta vulgaris) and chloroquine (a reference drug) against brain oxidative stress induced by Plasmodium berghei in male mice. Two protocols were applied in this study: the therapeutic and prophylactic protocols. The results of the therapeutic protocol revealed a significant decrease in the level of parasitemia caused by P. berghei. Additionally, the histopathological changes in various brain regions were markedly improved after treatment with betalains. Regarding the prophylactic protocol, betalains were able to protect the brain tissues from oxidative stress, inflammation, and disrupted neurotransmitters expected to occur as a result of infection by P. berghei. This was demonstrated by modulating the activities of brain antioxidants (SOD and GSH), inflammatory cytokines (IL-6, IL-10, IL-12, TNF-α, and INF-γ), and neurotransmitters (serotonin, epinephrine, and norepinephrine). This study has proven that using betalains as a treatment or as a preventive has a vital and effective role in confronting the brain histopathological, oxidative stress, and inflammatory changes induced by P. berghei infection.

Effect of neem leaf extract (Azadirachta indica) in reducing the degree of parasitemia and apoptosis in C57BL mice with cerebral malaria

Background and Aim

Brain malaria, which results from Plasmodium falciparum infection, is responsible for substantial fatalities and health issues. These processes, including cytoadherence, rosetting, and sequestration, induce an immune response, hypoxia, brain microvascular obstruction, disruption of the blood-brain barrier, and cell death. Parasitemia level can reveal the presence of infection and its association with apoptosis-related genes. Neem (Azadirachta indica) leaves with antimalarial properties could replace ineffective Indonesian malaria medications. This study was designed to evaluate the impact of neem leaf extract on cerebral malaria-induced parasitemia and neuron cell apoptosis in mice through an in vivo approach.

Materials and Methods

13-16 weeks old C57BL mice received infection by Plasmodium berghei strain ANKA. Parasitemia was estimated daily from the mice's tail blood. 8 mg, 12 mg, and 16 mg of a 96% ethanolic neem leaf extract were orally given for 6 days. Healthy, positive, and negative controls were included for treatment comparisons. On the 7th day, brain tissue was analyzed for (p > 0.05) gene expression. Through immunohistochemistry, both cell apoptosis in neurons expressing caspase-3 within a brain sample and the degree of parasitemia in a blood smear were assessed. The Pearson correlation test and one-way analysis of variance were employed to analyze the data.

Results

Neem leaf extract reduces parasitemia and neuron cell apoptosis at multiple dosages (p < 0.000). Apoptosis in brain neurons and parasitemia show a strong positive correlation (r = +0.939). Neem leaf extract at doses of 12 and 16 mg was the most effective in reducing parasitemia levels and causing cell death.

Conclusions

Neem leaf therapy significantly reduced the degree of parasitemia and cell apoptosis in C57BL mice compared with the control group without treatment (p = 0.05). This shows that neem leaves have the potential to be a candidate drug for malaria.

Cerebral malaria pathogenesis: Dissecting the role of CD4+ and CD8+ T-cells as major effectors in disease pathology

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum (P. falciparum) infection, with complex pathogenesis involving multiple factors, including the host's immunological response. T lymphocytes, specifically CD4+ T helper cells and CD8+ cytotoxic T cells, are crucial in controlling parasite growth and activating cells for parasite clearance via cytokine secretion. Contrary to this, reports also suggest the pathogenic nature of T lymphocytes as they are often involved in disease progression and severity. CD8+ cytotoxic T cells migrate to the host's brain vasculature, disrupting the blood-brain barrier and causing neurological manifestations. CD4+ T helper cells on the other hand play a variety of functions as they differentiate into different subtypes which may function as pro-inflammatory or anti-inflammatory. The excessive pro-inflammatory response in CM can lead to multi-organ failure, necessitating a check mechanism to maintain immune homeostasis. This is achieved by regulatory T cells and their characteristic cytokines, which counterbalance the pro-inflammatory immune response. Maintaining a critical balance between pro and anti-inflammatory responses is crucial for determining disease outcomes in CM. A slight change in this balance may contribute to a disease severity owing to an extreme inflammatory response or unrestricted parasite growth, a potential target for designing immunotherapeutic treatment approaches. The review briefly discusses the pathogenesis of CM and various mechanisms responsible for the disruption of the blood-brain barrier. It also highlights the role of different T cell subsets during infection and emphasizes the importance of balance between pro and anti-inflammatory T cells that ultimately decides the outcome of the disease.

DHA-rich fish oil plays a protective role against experimental cerebral malaria by controlling inflammatory and mechanical events from infection

Every year, thousands of children, particularly those under 5 years old, die because of cerebral malaria (CM). Following conventional treatment, approximately 25% of surviving individuals have lifelong severe neurocognitive sequelae. Therefore, improved conventional therapies or effective alternative therapies that prevent the severe infection are crucial. Omega-3 (Ω-3) polyunsaturated fatty acids (PUFAs) are known to have antioxidative and anti-inflammatory effects and protect against diverse neurological disorders, including Alzheimer's and Parkinson's diseases. However, little is known regarding the effects of Ω-3 PUFAs against parasitic infections. In this study, C57BL/6 mice received supplemental treatment of a fish oil rich in the Ω-3 PUFA, docosahexaenoic acid (DHA), which was started 15 days prior to infection with Plasmodium berghei ANKA and was maintained until the end of the study. Animals treated with the highest doses of DHA, 3.0 and 6.0 g/kg body weight, had 60 and 80% chance of survival, respectively, while all nontreated mice died by the 7th day postinfection due to CM. Furthermore, the parasite load during the critical period for CM development (5th to 11th day postinfection) was controlled in treated mice. However, after this period all animals developed high levels of parasitemia until the 20th day of infection. DHA treatment also effectively reduced blood-brain barrier (BBB) damage and brain edema and completely prevented brain hemorrhage and vascular occlusion. A strong anti-inflammatory profile was observed in the brains of DHA-treated mice, as well as, an increased number of neutrophil and reduced number of CD8+ T leukocytes in the spleen. Thus, this is the first study to demonstrate that the prophylactic use of DHA-rich fish oil exerts protective effects against experimental CM, reducing the mechanical and immunological events caused by the P. berghei ANKA infection.

Antiplasmodial and interferon-gamma-modulating activities of the aqueous extract of stone breaker (Phyllanthus niruri Linn.) in malaria infection

Plasmodium falciparum parasites are the primary cause of malaria across Africa. The problem of drug resistance to malaria is ever growing and novel therapeutic strategies need to be developed, particularly those targeting the parasite and also the host or host-pathogen interaction. Previous studies have shown that the development of cerebral malaria (CM) is related to dysregulation of the immune system in a murine malaria model of experimental cerebral malaria. It involves a complex interaction of events and interferon-gamma seems to be the unifying factor. Therefore, the antiplasmodial activity targeting the parasite and immunomodulatory strategies that reduce overall host inflammation, with IFN-γ in focus, could delay CM onset and prove beneficial in malaria infection therapy. Phyllanthus niruri is used to treat fever and other symptoms of malaria in Nigeria. Its modes of action as an anti-malarial remedy have not been exhaustively investigated. This study therefore examined the aqueous extract of P. niruri (PE) for its antiplasmodial activity in vitro using the Plasmodium falciparum HB3 strain. Furthermore, in vivo murine malaria model using the Plasmodium berghei ANKA strain was used to investigate its anti-malarial effects. We showed that PE has multiple anti-malarial effects, including anti-parasitic and host immunomodulatory activities. Co-culture of P. falciparum with PE and some of its phytoconstituents drastically reduced parasite number. PE also decreased parasitemia, and increased the survival of infected mice. We also observed that the integrity of the blood-brain barrier was maintained in the PE-treated mice. The results confirmed that PE showed moderate antiplasmodial activity. In vivo murine malaria model using P. berghei ANKA for experimental cerebral malaria revealed that PE suppressed parasite growth, and modulate the production of interferon-gamma. The findings demonstrate that PE affects malaria progression, targeting parasites and host cells.

High-throughput virtual screening approach of natural compounds as target inhibitors of plasmepsin-II

Plasmepsin II is a key enzyme in the life cycle of the Plasmodium falciparum parasite responsible for malaria, a disease that is causing deaths on a worldwide scale. Recently, plasmepsin II enzyme has gained much importance as an attractive drug target for the investigation of antimalarial drugs. In this sense, structure-based virtual screening have been utilized as tools in the process of discovering novel natural compounds based on quinoline as potential plasmepsin II inhibitors. Among the 58 quinoline derivatives isolated from different plants was screened by utilizing docking molecular, ADMET approaches, molecular dynamics simulation and MM-PBSA binding free energy. The first step in this work is building the 3 D structures of the plasmepsin II enzyme by using the SWISS-MODEL software. The optimized structures were subjected to virtual screening by Autodock Vina, an entity implicated in PyRx software. 21 were selected based on their binding affinity. The binding modes and interactions of the top-21 selected compounds were evaluated using AutoDock 4.2. Then, the pharmacokinetic proprieties and toxicity of these compounds were evaluated using ADMET analysis. Ten compounds were predicted to have ADMET characteristics with no side effects. Compounds M49 and M53 were found to be potential inhibitors. The stability of the selected two compounds was confirmed by MD simulation and MM/PBSA calculation during 200 ns. This study can be used to predict and to design new antimalarial drugs.Communicated by Ramaswamy H. Sarma.

Imaging features of fulminant cerebral malaria: A case report

Cerebral malaria is associated with high mortality and morbidity in patients infected with Plasmodium Falciparum. The mechanisms of cerebral malaria include sequestration of parasitized red blood cells in brain capillaries, production of cytokines, immune cell/platelet accumulation, and release of microparticles, resulting in disruption of the blood-brain barrier, which caused brain injuries. The severity of this reflects on neurological findings ranging from simple delirium to profound coma. We herein present unique magnetic resonance imaging findings of a case of fulminant cerebral malaria as computed tomography studies usually underestimate the extent of cerebral involvement in malaria.

Evaluation of chalcone derivatives for their role as antiparasitic and neuroprotectant in experimentally induced cerebral malaria mouse model

Cerebral malaria is a severe complication of Plasmodium falciparum infection with a complex pathophysiology. The current course of treatment is ineffective in lowering mortality or post-treatment side effects such as neurological and cognitive abnormalities. Chalcones are enormously distributed in spices, fruits, vegetables, tea, and soy-based foodstuffs that are well known for their antimalarial activity, and in recent years they have been widely explored for brain diseases like Alzheimer's disease. Therefore, considering the previous background of chalcones serving as both antimalarial and neuroprotective, the present study aimed to study the effect of these chalcone derivatives on an experimental model of cerebral malaria (CM). CM-induced mice were tested behaviorally (elevated plus maze, rota rod test, and hanging wire test), biochemically (nitric oxide estimation, cytokines (IL-1, IL-6, IL-10, IL-12p70, TNF, IFN-y), histopathologically and immunohistochemically, and finally ultrastructural changes were examined using a transmission electron microscope. All three chalcones treated groups showed a significant (p < 0.001) decrease in percentage parasitemia at the 10th day post-infection. Mild anxiolytic activity of chalcones as compared to standard treatment with quinine has been observed during behavior tests. No pigment deposition was observed in the QNN-T group and other chalcone derivative treated groups. Rosette formation was seen in the derivative 1 treated group. The present derivatives may be pioneered by various research and science groups to design such a scaffold that will be a future antimalarial with therapeutic potential or, because of its immunomodulatory properties, it could be used as an adjunct therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03676-y.

Severe Malaria in an Adult Patient from Low-Endemic Area in Flores Island, East Nusa Tenggara

Malaria is an infection caused by protozoa of the genus Plasmodium, commonly found in tropical and subtropical regions worldwide. Plasmodium falciparum causes the most severe form of the disease and may progress to life-threatening manifestations. This case describes a 26-year-old man who suffered cerebral malaria with multiple organ dysfunction and successfully recovered despite poor initial prognosis. Negligent and late diagnosis of malaria leads to severe complications and a worse prognosis. This case emphasizes despite living in a low-endemic malaria area, physicians should remain meticulous and consider malaria as differential diagnosis even after initially presenting with nonspecific symptoms. Consequently, malarial screening should be performed to modify the risk of mortality. Furthermore, close monitoring and early administration of intravenous artesunate are also particularly critical.

Diagnosis of cerebral malaria: Tools to reduce Plasmodium falciparum associated mortality

Cerebral malaria (CM) is a major cause of mortality in Plasmodium falciparum (Pf) infection and is associated with the sequestration of parasitised erythrocytes in the microvasculature of the host's vital organs. Prompt diagnosis and treatment are key to a positive outcome in CM. However, current diagnostic tools remain inadequate to assess the degree of brain dysfunction associated with CM before the window for effective treatment closes. Several host and parasite factor-based biomarkers have been suggested as rapid diagnostic tools with potential for early CM diagnosis, however, no specific biomarker signature has been validated. Here, we provide an updated review on promising CM biomarker candidates and evaluate their applicability as point-of-care tools in malaria-endemic areas.

Cerebral Malaria and Neuronal Implications of Plasmodium Falciparum Infection: From Mechanisms to Advanced Models

Reorganization of host red blood cells by the malaria parasite Plasmodium falciparum enables their sequestration via attachment to the microvasculature. This artificially increases the dwelling time of the infected red blood cells within inner organs such as the brain, which can lead to cerebral malaria. Cerebral malaria is the deadliest complication patients infected with P. falciparum can experience and still remains a major public health concern despite effective antimalarial therapies. Here, the current understanding of the effect of P. falciparum cytoadherence and their secreted proteins on structural features of the human blood-brain barrier and their involvement in the pathogenesis of cerebral malaria are highlighted. Advanced 2D and 3D in vitro models are further assessed to study this devastating interaction between parasite and host. A better understanding of the molecular mechanisms leading to neuronal and cognitive deficits in cerebral malaria will be pivotal in devising new strategies to treat and prevent blood-brain barrier dysfunction and subsequent neurological damage in patients with cerebral malaria.

Mouse Models for Unravelling Immunology of Blood Stage Malaria

Malaria comprises a spectrum of disease syndromes and the immune system is a major participant in malarial disease. This is particularly true in relation to the immune responses elicited against blood stages of Plasmodium-parasites that are responsible for the pathogenesis of infection. Mouse models of malaria are commonly used to dissect the immune mechanisms underlying disease. While no single mouse model of Plasmodium infection completely recapitulates all the features of malaria in humans, collectively the existing models are invaluable for defining the events that lead to the immunopathogenesis of malaria. Here we review the different mouse models of Plasmodium infection that are available, and highlight some of the main contributions these models have made with regards to identifying immune mechanisms of parasite control and the immunopathogenesis of malaria.

Cerebral Malaria Presenting With Shock in an Adolescent: A Case Report

Cerebral malaria (CM) is a severe infection of the brain caused by the parasite Plasmodium falciparum. It is commonly found as a complication of infection traveling to the brain. CM has a poor prognosis unless promptly identified and treated. This case report describes a 15-year-old girl who suddenly started experiencing a tonic-clonic seizure while playing. At the time of arrival at the emergency department, her vital signs were consistent with shock. She had hepatomegaly on physical examination, a hallmark of malarial infection due to an immune response against the proliferation of the protozoa. Peripheral blood smear for malaria parasites was positive for P. falciparum and P. vivax. The patient was started on intravenous (IV) saline, IV phenytoin, and IV metoclopramide. She was also transfused with two units of packed red blood cells. The patient was subsequently diagnosed with CM. For most patients, the course of treatment includes aggressive therapy with anti-malarial medications. She was started on broad-spectrum antibiotics and anti-malarial medications. Following two weeks of treatment, her condition improved significantly and she was discharged.

Neurotransmitters and molecular chaperones interactions in cerebral malaria: Is there a missing link?

Plasmodium falciparum is responsible for the most severe and deadliest human malaria infection. The most serious complication of this infection is cerebral malaria. Among the proposed hypotheses that seek to explain the manifestation of the neurological syndrome in cerebral malaria is the vascular occlusion/sequestration/mechanic hypothesis, the cytokine storm or inflammatory theory, or a combination of both. Unfortunately, despite the increasing volume of scientific information on cerebral malaria, our understanding of its pathophysiologic mechanism(s) is still very limited. In a bid to maintain its survival and development, P. falciparum exports a large number of proteins into the cytosol of the infected host red blood cell. Prominent among these are the P. falciparum erythrocytes membrane protein 1 (PfEMP1), P. falciparum histidine-rich protein II (PfHRP2), and P. falciparum heat shock proteins 70-x (PfHsp70-x). Functional activities and interaction of these proteins with one another and with recruited host resident proteins are critical factors in the pathology of malaria in general and cerebral malaria in particular. Furthermore, several neurological impairments, including cognitive, behavioral, and motor dysfunctions, are known to be associated with cerebral malaria. Also, the available evidence has implicated glutamate and glutamatergic pathways, coupled with a resultant alteration in serotonin, dopamine, norepinephrine, and histamine production. While seeking to improve our understanding of the pathophysiology of cerebral malaria, this article seeks to explore the possible links between host/parasite chaperones, and neurotransmitters, in relation to other molecular players in the pathology of cerebral malaria, to explore such links in antimalarial drug discovery.

Increased Expression of Multiple Co-Inhibitory Molecules on Malaria-Induced CD8+ T Cells Are Associated With Increased Function Instead of Exhaustion

Activated cytotoxic CD8+ T cells can selectively kill target cells in an antigen-specific manner. However, their prolonged activation often has detrimental effects on tissue homeostasis and function. Indeed, overwhelming cytotoxic activity of CD8+ T cells can drive immunopathology, and therefore, the extent and duration of CD8+ T cell effector function needs to be tightly regulated. One way to regulate CD8+ T cell function is their suppression through engagement of co-inhibitory molecules to their cognate ligands (e.g., LAG-3, PD-1, TIM-3, TIGIT and CTLA-4). During chronic antigen exposure, the expression of co-inhibitory molecules is associated with a loss of T cell function, termed T cell exhaustion and blockade of co-inhibitory pathways often restores T cell function. We addressed the effect of co-inhibitory molecule expression on CD8+ T cell function during acute antigen exposure using experimental malaria. To this end, we infected OT-I mice with a transgenic P. berghei ANKA strain that expresses ovalbumin (PbTG), which enables the characterization of antigen-specific CD8+ T cell responses. We then compared antigen-specific CD8+ T cell populations expressing different levels of the co-inhibitory molecules. High expression of LAG-3 correlated with high expression of PD-1, TIGIT, TIM-3 and CTLA-4. Contrary to what has been described during chronic antigen exposure, antigen-specific CD8+ T cells with the highest expression of LAG-3 appeared to be fully functional during acute malaria. We evaluated this by measuring IFN-γ, Granzyme B and Perforin production and confirmed the results by employing a newly developed T cell cytotoxicity assay. We found that LAG-3high CD8+ T cells are more cytotoxic than LAG-3low or activated but LAG-3neg CD8+ T cells. In conclusion, our data imply that expression of co-inhibitory molecules in acute malaria is not necessarily associated with functional exhaustion but may be associated with an overwhelming T cell activation. Taken together, our findings shed new light on the induction of co-inhibitory molecules during acute T cell activation with ramifications for immunomodulatory therapies targeting these molecules in acute infectious diseases.

Listeria monocytogenes Inoculation Impedes the Development of Brain Pathology in Experimental Cerebral Malaria by Inhibition of Parasitemia

Cerebral malaria (CM) is a serious central nervous system dysfunction caused by Plasmodium falciparum infection. In this study, we investigated the effect of Listeria monocytogenes (Lm) inoculation on experimental cerebral malaria (ECM) using Plasmodium berghei ANKA (PbA)-infected C57BL/6 mice. Live Lm inoculation inhibited the parasitemia and alleviated ECM symptoms. The protective effect against ECM symptoms was connected with improved brain pathology manifested as a less-damaged blood-brain barrier, decreased parasite sequestration, and milder local inflammation. Meanwhile, Lm inoculation decreased expression of cell adhesion molecules (ICAM-1 and VCAM-1) and accumulation of pathogenic CD8⁺ T cells in the brain. In keeping with the suppression of parasitemia, there was an upregulation of IFN-γ, IL-12, MCP-1, and NO expression in the spleen by Lm inoculation upon PbA infection. Early treatment with exogenous IFN-γ exhibited a similar effect to Lm inoculation on PbA infection. Taken together, Lm inoculation impedes the development of brain pathology in ECM, and early systemic IFN-γ production may play a critical role in these protective effects.

Chronic cerebral aspects of long COVID, post-stroke syndromes and similar states share their pathogenesis and perispinal etanercept treatment logic

The chronic neurological aspects of traumatic brain injury, post-stroke syndromes, long COVID-19, persistent Lyme disease, and influenza encephalopathy having close pathophysiological parallels that warrant being investigated in an integrated manner. A mechanism, common to all, for this persistence of the range of symptoms common to these conditions is described. While TNF maintains cerebral homeostasis, its excessive production through either pathogen-associated molecular patterns or damage-associated molecular patterns activity associates with the persistence of the symptoms common across both infectious and non-infectious conditions. The case is made that this shared chronicity arises from a positive feedback loop causing the persistence of the activation of microglia by the TNF that these cells generate. Lowering this excess TNF is the logical way to reducing this persistent, TNF-maintained, microglial activation. While too large to negotiate the blood-brain barrier effectively, the specific anti-TNF biological, etanercept, shows promise when administered by the perispinal route, which allows it to bypass this obstruction.

Malaria Related Neurocognitive Deficits and Behavioral Alterations

Typical of tropical and subtropical regions, malaria is caused by protozoa of the genus Plasmodium and is, still today, despite all efforts and advances in controlling the disease, a major issue of public health. Its clinical course can present either as the classic episodes of fever, sweating, chills and headache or as nonspecific symptoms of acute febrile syndromes and may evolve to severe forms. Survivors of cerebral malaria, the most severe and lethal complication of the disease, might develop neurological, cognitive and behavioral sequelae. This overview discusses the neurocognitive deficits and behavioral alterations resulting from human naturally acquired infections and murine experimental models of malaria. We highlighted recent reports of cognitive and behavioral sequelae of non-severe malaria, the most prevalent clinical form of the disease worldwide. These sequelae have gained more attention in recent years and therapies for them are required and demand advances in the understanding of neuropathogenesis. Recent studies using experimental murine models point to immunomodulation as a potential approach to prevent or revert neurocognitive sequelae of malaria.

RNA-seq-based transcriptome analysis of the anti-inflammatory effect of artesunate in the early treatment of the mouse cerebral malaria model

The present study provides new insights into the molecular mechanisms by which artesunate improves prognosis in cerebral malaria, in particular inhibition of host cytokine storm.

Artesunate and Tetramethylpyrazine Exert Effects on Experimental Cerebral Malaria in a Mechanism of Protein S-Nitrosylation

Cerebral malaria (CM) is caused by Plasmodium falciparum, resulting in severe sequelae; one of its pathogenic factors is the low bioavailability of nitric oxide (NO). Our previous study suggested that the combination of artesunate (AS) and tetramethylpyrazine (TMP) exerts an adjuvant therapeutic effect on the symptoms of experimental CM (ECM) and that NO regulation plays an important role. In the present study, we further verified the effects of AS+TMP on cerebral blood flow (CBF) and detected NO-related indicators. We focused on the role of NO through S-nitrosoproteome based on previous proteomics data and explored the mechanism of AS+TMP for improving pathological ECM symptoms. We observed that AS+TMP reduces adhesion, increases CBF, and regulates NO synthase (NOS) activity, thereby regulating the level of S-nitrosothiols, such as metabolism-related or neuro-associated receptors, for improving ECM symptoms. These results demonstrated that AS+TMP could be an effective strategy in adjuvant therapy of CM.

Insights into Plasmodium and SARS-CoV-2 co-infection driven neurological manifestations

In malaria-endemic regions, people often get exposed to various pathogens simultaneously, generating co-infection scenarios. In such scenarios, overlapping symptoms pose serious diagnostic challenges. The delayed diagnosis may lead to an increase in disease severity and catastrophic events. Recent coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected various areas globally, including malaria-endemic regions. The Plasmodium and SARS-CoV-2 co-infection and its effect on health are yet unexplored. We present a case report of a previously healthy, middle-aged individual from the malaria-endemic area who suffered SARS-CoV-2 and Plasmodium falciparum co-infection. The patient developed severe disease indications in a short time period. The patient showed neurological symptoms, altered hematological as well as liver-test parameters, and subsequent death in a narrow time span. We hereby discuss the various aspects of this case regarding treatment and hematological parameters. Further, we have put forward perspectives related to the mechanism behind severity and neurological symptoms in this fatal parasite-virus co-infection case. In malaria-endemic regions, due to overlapping symptoms, suspected COVID-19 patients should also be monitored for diagnosis of malaria without any delay. The SARS-CoV-2 and Plasmodium co-infection could increase the disease severity in a short time span. In treatment, dexamethasone may not help in severe cases having malaria as well as COVID-19 positive status and needs further exploration.

Co-infection of hepatitis E virus and Plasmodium falciparum malaria: A genuine risk in sub-Saharan Africa

BACKGROUND

There is a high prevalence of malaria and viral hepatitis in South Africa. Co-infection with Plasmodium malaria (leading to cerebral malaria) and hepatitis E virus (HEV) is a rare phenomenon.

CASE PRESENTATION

A 33-year-old African American male with no past medical history developed altered mental status on his return from Ivory Coast. His blood tests were significant for renal and liver failure and a high Plasmodium parasite burden of 33% on the blood smear. Interestingly, he also had a positive result for hepatitis E IgM. The patient was effectively treated with aggressive hydration and intravenous (IV) artesunate.

CONCLUSION

Our report is the first to our knowledge in the cerebral malaria literature on a patient with hepatitis E co-infection. This exciting case emphasizes the importance of considering all kinds of endemic infectious diseases when evaluating sick returning travelers presenting to the emergency department.

Broader Insights into Understanding Tumor Necrosis Factor and Neurodegenerative Disease Pathogenesis Infer New Therapeutic Approaches

Proinflammatory cytokines such as tumor necrosis factor (TNF), with its now appreciated key roles in neurophysiology as well as neuropathophysiology, are sufficiently well-documented to be useful tools for enquiry into the natural history of neurodegenerative diseases. We review the broader literature on TNF to rationalize why abruptly-acquired neurodegenerative states do not exhibit the remorseless clinical progression seen in those states with gradual onsets. We propose that the three typically non-worsening neurodegenerative syndromes, post-stroke, post-traumatic brain injury (TBI), and post cardiac arrest, usually become and remain static because of excess cerebral TNF induced by the initial dramatic peak keeping microglia chronically activated through an autocrine loop of microglial activation through excess cerebral TNF. The existence of this autocrine loop rationalizes post-damage repair with perispinal etanercept and proposes a treatment for cerebral aspects of COVID-19 chronicity. Another insufficiently considered aspect of cerebral proinflammatory cytokines is the fitness of the endogenous cerebral anti-TNF system provided by norepinephrine (NE), generated and distributed throughout the brain from the locus coeruleus (LC). We propose that an intact LC, and therefore an intact NE-mediated endogenous anti-cerebral TNF system, plus the DAMP (damage or danger-associated molecular pattern) input having diminished, is what allows post-stroke, post-TBI, and post cardiac arrest patients a strong long-term survival advantage over Alzheimer's disease and Parkinson's disease sufferers. In contrast, Alzheimer's disease and Parkinson's disease patients remorselessly worsen, being handicapped by sustained, accumulating, DAMP and PAMP (pathogen-associated molecular patterns) input, as well as loss of the LC-origin, NE-mediated, endogenous anti-cerebral TNF system. Adrenergic receptor agonists may counter this.

Eugenol disrupts Plasmodium falciparum intracellular development during the erythrocytic cycle and protects against cerebral malaria

BACKGROUND

Malaria is a parasitic disease that compromises the human host. Currently, control of the Plasmodium falciparum burden is centered on artemisinin-based combination therapies. However, decreased sensitivity to artemisinin and derivatives has been reported, therefore it is important to identify new therapeutic strategies.

METHOD

We used human erythrocytes infected with P. falciparum and experimental cerebral malaria (ECM) animal model to assess the potential antimalarial effect of eugenol, a component of clove bud essential oil.

RESULTS

Plasmodium falciparum cultures treated with increasing concentrations of eugenol reduced parasitemia in a dose-dependent manner, with IC₅₀ of 532.42 ± 29.55 μM. This effect seems to be irreversible and maintained even in the presence of high parasitemia. The prominent effect of eugenol was detected in the evolution from schizont to ring forms, inducing important morphological changes, indicating a disruption in the development of the erythrocytic cycle. Aberrant structural modification was observed by electron microscopy, showing the separation of the two nuclear membrane leaflets as well as other subcellular membranes, such as from the digestive vacuole. Importantly, in vivo studies using ECM revealed a reduction in blood parasitemia and cerebral edema when mice were treated for 6 consecutive days upon infection.

CONCLUSIONS

These data suggest a potential effect of eugenol against Plasmodium sp. with an impact on cerebral malaria.

GENERAL SIGNIFICANCE

Our results provide a rational basis for the use of eugenol in therapeutic strategies to the treatment of malaria.

Treatment of Experimental Cerebral Malaria by Slow Release of Artemisone From Injectable Pasty Formulation

Malaria caused by Plasmodium falciparum causes numerous cases of morbidity with about 400,000 deaths yearly owing, mainly, to inflammation leading to cerebral malaria (CM). CM conventionally is treated by repetitive administration of anti-plasmodial drugs and supportive non-specific drugs, for about a week. A mouse model of CM caused by Plasmodium berghei ANKA, in which brain and systemic clinical pathologies occur followed by sudden death within about a week, was used to study the effect of artemisone, a relatively new artemisinin, within an injectable pasty polymer formulated for its controlled release. The parasites were exposed to the drug over several days at a non-toxic concentrations for the mice but high enough to affect the parasites. Artemisone was also tested in cultures of bacteria, cancer cells and P. falciparum to evaluate the specificity and suitability of these cells for examining the release of artemisone from its carrier. Cultures of P. falciparum were the most suitable. Artemisone released from subcutaneous injected poly(sebacic acid-ricinoleic acid) (PSARA) pasty polymer, reduced parasitemias in infected mice, prolonged survival and prevented death in most of the infected mice. Successful prophylactic treatment before infection proved that there was a slow release of the drug for about a week, which contrasts with the three hour half-life that occurs after injection of just the drug. Treatment with artemisone within the polymer, even at a late stage of the disease, helped to prevent or, at least, delay accompanying severe symptoms. In some cases, treatment prevented death of CM and the mice died later of anemia. Postponing the severe clinical symptoms is also beneficial in cases of human malaria, giving more time for an appropriate diagnosis and treatment before severe symptoms appear. The method presented here may also be useful for combination therapy of anti-plasmodial and immunomodulatory drugs.

Neurological disorder and psychosocial aspects of cerebral malaria: what is new on its pathogenesis and complications? A minireview

Recently, malaria is remain considered as the most prevalent infectious disease, affecting the human health globally. High morbidity and mortality worldwide is often allied with cerebral malaria (CM) based disorders of the central nervous system, especially across many tropical and sub-tropical regions. These disorders are characterised by the infection of Plasmodium species, which leads to acute or chronic neurological disorders, even after having active/effective antimalarial drugs. Furthermore, even during the treatment, individual remain sensitive for neurological impairments in the form of decrease blood flow and vascular obstruction in brain including many more other changes. This review briefly explains and update on the epidemiology, burden of disease, pathogenesis and role of CM in neurological disorders with behaviour and function in mouse and human models. Moreover, the social stigma, which plays an important role in neurological disorders and a factor for assessing CM, is also discussed in this review.

Effect of Artesunate on Leishmania Amazonesis Induced Neuroinflammation and Nociceptive Behavior in Male Balb/C Mice

Simple Summary

Leishmaniasis is a multisystemic zoonotic disease with several symptoms, and treating this disease is a great challenge for veterinary medicine. Artemisinin derivatives are currently the most widely used drugs for the treatment of malaria, especially for their excellent safety profile and low cost. Artesunate is a more stable derivative of its precursor, artemisin, and has been shown to be a pluripotent agent with different pharmacological actions. In this study, we evaluated the role of neuroinflammation in leishmaniasis and its correlation with pain and sickness behavior, and the anti-inflammatory and neuroprotective effects of artesunate in a murine model of Leishmania amazonensis infection in BALB/c mice. The results from this study indicate that artesunate is a good candidate for treatment and/or as an adjuvant in anti- leishmaniasis therapy, and for preventing and alleviating leishmaniasis-induced pain and neuroinflammation.

Abstract

Background: Leishmaniasis is a multisystemic zoonotic disease with several symptoms, including neurological disorders. Leishmaniasis is accompanied by an increase in nociceptive behaviors, linked to the presence of a chronic inflammatory state, in both peripheral tissue and the central nervous system. Artesunate is a more stable derivative of its precursor artemisin and has been shown to be a pluripotent agent with different pharmacological actions. Methods: In this study, we investigated the effects of artesunate in Leishmaniaamazonensi- infected BALB/c mice, evaluating its effectiveness in reducing inflammation, neuroinflammation, and nociceptive and sickness behaviors. Results: Our results demonstrate a significant increase in pain sensitivity and sickness behaviors after L. amazonensis infection. Moreover, the infection induced a significant increase in inflammatory response at both the paw and spinal cord level. Treatment with artesunate was able to induce a significant decrease in tissue inflammation and neuroinflammation and thus induce a significant decrease in pain sensitivity and sickness behaviors. Conclusions: The results from this study indicate that artesunate is a good candidate for treatment and/or as an adjuvant in leishmanicidal therapy, and to prevent and alleviate leishmaniasis-induced pain and neuroinflammation and thereby improve the quality of life of leishmaniasis patients.

Molecular and Histologic Diagnosis of Central Nervous System Infections

Infections of the central nervous system cause significant morbidity and mortality in immunocompetent and immunocompromised individuals. A wide variety of microorganisms can cause infections, including bacteria, mycobacteria, fungi, viruses, and parasites. Although less invasive testing is preferred, surgical biopsy may be necessary to collect diagnostic tissue. Histologic findings, including special stains and immunohistochemistry, can provide a morphologic diagnosis in many cases, which can be further classified by molecular testing. Correlation of molecular, culture, and other laboratory results with histologic findings is essential for an accurate diagnosis, and to minimize false positives from microbial contamination.