Cerebral malaria: mechanisms of brain injury and strategies for improved neurocognitive outcome

The aetiologies, mortality, and disability of non-traumatic coma in African children: a systematic review and meta-analysis

BACKGROUND

Non-traumatic coma in African children is a common life-threatening presentation often leading to hospital attendance. We aimed to estimate the distribution of non-traumatic coma causes and outcomes, including disease-specific outcomes, for which evidence is scarce.

METHODS

We systematically reviewed MEDLINE, Embase, and Scopus databases from inception to Feb 6, 2024. We included studies recruiting children (aged 1 month to 16 years) with non-traumatic coma (Blantyre Coma Scale score ≤2, ie deep coma or comparable alternative) from any African country. Disease-specific studies were included if outcomes were reported. Primary data were requested where required. We used a DerSimonian-Laird random effects model to calculate pooled estimates for prevalence of causes, mortality, and morbidity (in-hospital and post-discharge), including analysis of mortality by temporality. This study was registered with PROSPERO (CRD4202014193).

FINDINGS

We screened 16 666 articles. 138 studies were eligible for analysis, reporting causes, outcome data, or both from 35 027 children with non-traumatic coma in 30 African countries. 114 (89%) of 128 studies were determined to be high quality. Among the causes, cerebral malaria had highest pooled prevalence at 58% (95% CI 48-69), encephalopathy of unknown cause was associated with 23% (9-36) of cases, and acute bacterial meningitis was the cause of 10% (8-12) of cases, with all other causes representing lower proportions of cases. Pooled overall case-fatality rates were 17% (16-19) for cerebral malaria, 37% (20-55) for unknown encephalopathy, and 45% (34-55) for acute bacterial meningitis. By meta-regression, there was no significant difference in cerebral malaria (p=0·98), acute bacterial meningitis (p=0·99), or all-cause coma (p=0·081) mortality by year of study. There was no substantial difference in deaths associated with cerebral malaria in-hospital compared with post-discharge (17% [16-19] vs (18% [16-20]). Mortality was higher post-discharge than in-hospital in most non-malarial comas, including acute bacterial meningitis (39% [26-52]) vs 53% [38-69]). Disability associated with cerebral malaria was 11% (9-12). Pooled disability outcomes associated with other non-malarial diseases were largely absent.

INTERPRETATION

The prevalence and outcomes of cerebral malaria and meningitis associated with non-traumatic coma were strikingly static across five decades. Enhanced molecular and radiological diagnostics, investment, policy making, community awareness, and health service provision are all required to facilitate earlier referral to specialist centres, to drive a step-change in diagnostic yield and treatment options to improve these outcomes.

FUNDING

Wellcome Trust.

TRANSLATIONS

For the Chichewa, French and Portuguese translations of the abstract see Supplementary Materials section.

Determinants of retinopathy and short-term neurological outcomes after cerebral malaria

Neurological abnormalities are frequent after cerebral malaria (CM) resolves. The identification of survivors that should be prioritized during follow-up after CM is necessary for post-hospitalization care. We analysed social, clinical, and immune determinants of malarial retinopathy (MR) and short-term neurological outcomes after CM. Children aged 24 to 71 months with CM were prospectively followed-up until 28 days after admission at two hospitals in Benin. Direct ophthalmoscopy was performed shortly after admission. Plasma biomarkers were measured at admission. A neurocognitive deficit screener was administered at discharge and 21-28 days after admission. Of 70 children, 20 died before discharge (28.6%). Neurological deficits decreased from 100% on admission to 48.9% at discharge, and to 16.7% at 21-28 days after admission. MR was found in 58% of children. In multivariate analysis, factors associated with MR were a traditional consultation before admission and study site. In addition, neurological deficits were associated with MR (Odds Ratio 5.54 95% CI (1.30-23.54)). In univariate analysis, higher plasma levels of angiopoietin-2 were associated with neurological deficit at discharge and at days 21-28 post-admission. Therefore, MR and endothelium activation may be markers of neurological deficit, the former at hospital discharge and the latter at discharge and at D21-D28 post-admission.

Prevalence and risk factors of gross neurologic deficits in children after severe malaria: a systematic review protocol

BACKGROUND

Children exposed to severe malaria may recover with gross neurologic deficits (GND). Several risk factors for GND after cerebral malaria (CM), the deadliest form of severe malaria, have been identified in children. However, there is inconsistency between previously reported and more recent findings. Although CM patients are the most likely group to develop GND, it is not clear if other forms of severe malaria (non-CM) may also contribute to malaria-related GND. The objective of this systematic review is to synthesize evidence on the prevalence and risk factors for GND in children after severe malaria.

METHODS

The systematic review will be conducted according to recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols (PRISMA-P). Relevant research articles will be identified using relevant search terms from the following databases: MEDLINE, Embase, Web of Science, and Global Index Medicus (GIM). The articles will be screened at title and abstract and then at full text for inclusion using a priori eligibility criteria. Data extraction will be carried out using a tool developed and optimized in an Excel spreadsheet. Risk of bias will be assessed using appropriate tools including Risk Of Bias In Non-randomized Studies of Exposures (ROBINS-E) and the Cochrane Risk of Bias 2.0 (ROB2) for randomized control trials (RCTs), and where appropriate, publication bias will be assessed using a funnel plot. A random-effects meta-analysis or synthesis without meta-analysis (SWiM) will be performed as appropriate, and the results will be presented in tables and graphs.

CONCLUSION

Findings from this systematic review will inform policymakers on the planning, design, and implementation of interventions targeting the treatment and rehabilitation of GND following severe malaria in children.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022297109.

Cerebral manifestations of falciparum malaria in adults: more than meets the eye

The application of neuroimaging techniques to patients with Plasmodium falciparum infection has uncovered a wide range of brain changes not only in cerebral malaria but also in noncomatose patients. We propose several hypotheses to unify findings across the spectrum of clinical malaria in adults and highlight the urgent need to evaluate potential long-term effects of cerebral alterations on neurocognition in this understudied age group.

Imaging the artery of Percheron: a pictorial review of associated pathology with important mimics of bithalamic abnormalities

BACKGROUND AND PURPOSE

The Artery of Percheron (AoP) supplying bilateral paramedian thalami and rostral midbrain is a rare anatomical variant. In the event of occlusion of AoP, a characteristic pattern of ischaemia is seen, presenting as bithalamic signal abnormality on magnetic resonance imaging (MRI). However, this particular imaging finding has significant radiological and clinical overlap with other conditions, necessitating a comprehensive understanding of the imaging characteristics and potential differential diagnosis. The aim of this pictorial essay is to provide a visual documentation of varying appearances of AoP infarction on imaging and highlighting other important pathologies that may cause similar appearance.

METHODS

Retrospective collection and review of imaging from patients with confirmed AoP infarction and other pathologies causing bithalamic signal abnormalities and identify crucial imaging caveats for differentiation.

RESULTS

We present a comprehensive visual spectrum of AoP infarction patterns, including bithalamic involvement (paramedian thalamic lesions) with or without midbrain involvement. Additionally, the "V" sign, observed on FLAIR and DWI sequences, is fairly characteristic of AoP infarction. Other important vascular causes seen include top of basilar artery syndrome, internal cerebral vein thrombosis as well as neoplastic lesions including diffuse midline glioma (DMG) H3 K27-altered. Additionally various inflammatory, metabolic and infective etiologies including viral encephalitis like Japanese encephalitis can cause a similar appearance.

CONCLUSIONS

This pictorial essay demonstrates the diverse patterns of AoP infarction and emphasizes the significance of recognizing important mimics of this condition, highlighting the need for a meticulous evaluation. Improved awareness and understanding of these imaging characteristics will contribute to more effective management of patients with thalamic strokes.

Microbiome-mediated modulation of immune memory to P. yoelii affects the resistance to secondary cerebral malaria challenge

Malaria is caused by protozoan parasites in the genus Plasmodium. Over time individuals slowly develop clinical immunity to malaria, but this process occurs at variable rates, and the mechanism of protection is not fully understood. We have recently demonstrated that in genetically identical C57BL/6N mice, gut microbiota composition dramatically impacts the quality of the humoral immune response to Plasmodium yoelii and subsequent protection against a lethal secondary challenge with Plasmodium berghei ANKA in C57BL/6N mice. Here, we utilize this genetically identical, gut microbiome-dependent model to investigate how the gut microbiota modulate immunological memory, hypothesizing that the gut microbiome impacts the formation and functionality of immune memory. In support of this hypothesis, P. yoelii hyperparasitemia-resistant C57BL/6N mice exhibit increased protection against P. berghei ANKA-induced experimental cerebral malaria (ECM) compared to P. yoelii hyperparasitemia-susceptible C57BL/6N mice. Despite differences in protection against ECM, P. yoelii-resistant and -susceptible mice accumulate similar numbers of memory B cells (MBCs) and memory T cells. Following challenge with P. berghei ANKA, P. yoelii-resistant mice generated more rapid germinal center reactions; however, P. yoelii-resistant and -susceptible mice had similar titers of P. yoelii- and P. berghei-specific antibodies. In contrast, P. yoelii-resistant mice had an increased number of regulatory T cells in response to secondary challenge with P. berghei ANKA, which may dampen the immune-mediated breakdown of the blood-brain barrier and susceptibility to P. berghei-induced ECM. These findings demonstrate the ability of the gut microbiome to shape immune memory and the potential to enhance resistance to severe malaria outcomes.

Epidemiology, clinical spectrum, and outcomes of severe malaria in Eastern Uganda: a prospective study

BACKGROUND

In sub-Saharan Africa, malaria remains a public health problem despite some reports of declining incidence in the period 2000-2018. Since 2019, there have been some reports of disease epidemics and resurgences in areas that had registered steep declines and unusual clinical presentations. This study aimed to describe the epidemiology, clinical spectrum, and outcomes of severe malaria in children among malaria-endemic Eastern Uganda, a region that has recently experienced disease epidemics.

METHODS

This prospective study was conducted at Mbale Regional Referral Hospital, Uganda, from 08th May 2019 to August 15, 2023, as part of the Malaria Epidemiological, Pathophysiological and Intervention studies in Highly Endemic Eastern Uganda (EDCTP-TMA2016SF-1514-MEPIE Study). Children aged 60 days to 12 years who at admission tested positive for malaria and fulfilled the clinical World Health Organization criteria for surveillance of severe malaria were enrolled into the study following appropriate informed consent. Data were collected using a customized proforma on social demographic characteristics, clinical presentation, treatment, and outcomes. Laboratory analyses included complete blood counts, lactate, glucose, blood gases, electrolytes, metabolites, and coagulation markers. In addition, urinalysis using dipsticks was done. Data were analysed using STATA V15. The study had ethical and regulatory approval before data collection commenced.

RESULTS

A total of 1,379 participants were recruited. The median age was 4 years (2 months-12 years). Most children 757/1379 (54.9%) were under 5 years, and 825/1379 (59.8%) were males. The common symptoms were fever 1368 (99.2%), poor appetite 1095 (79.5%), inability to sit upright 1051 (76.2%), vomiting 944 (68.4%) and yellow eyes 833 (60.4%). The common signs included prostration, haemoglobinuria and jaundice. Prolonged hospitalization was found in 284/1339 (21.2%) and was associated with impaired consciousness 116/166 (30.1%), P = 0.003; haemoglobinuria 514/705 (27.1%), P < 0.001 and jaundice 505/690 (26.8%) P < 0.001. The overall mortality was 40/1347 (3.0%). Children who had > 1 severity feature were at a higher risk of mortality.

CONCLUSION

In this prospective study of children with severe malaria in Eastern Uganda, the overall mortality was 3.0% and the more the disease clinical syndromes the higher the risk of death.

Unveiling new perspectives about the onset of neurological and cognitive deficits in cerebral malaria: exploring cellular and neurochemical mechanisms

Cerebral malaria is the most severe and lethal complication caused by Plasmodium falciparum infection, leading to critical neurological impairments and long-term cognitive, behavioral, and neurological sequelae in survivors, particularly affecting children under the age of five. Various hypotheses have been proposed to explain the neurological syndrome associated to cerebral malaria condition, including vascular occlusion and sequestration, cytokine storm or inflammatory response, or a combination of these mechanisms and despite extensive research and a growing range of scientific information, the precise pathophysiological mechanism remains poorly understood. In this sense, this review aims to explore the neurological impairment in cerebral malaria and elucidate novel mechanisms to explain the severity of this disease. Recent evidence implicates glutamate and glutamatergic pathways in the onset of cerebral malaria, alongside the impairments in the metabolic activity of other molecules such as dopamine and kynurenic acid. These neurotransmitters pathways may play a crucial role in the pathogenesis of cerebral malaria, potentially interacting with other molecular players. By enhancing our understanding in the pathophysiology of cerebral malaria, this article seeks to explore new hypotheses regarding the involvement of neurotransmitters and their interactions with other molecular targets, thereby contributing to the overall pathology of cerebral malaria.

Cerebral Malaria in Adults: A Retrospective Descriptive Analysis of 80 Cases in a Tertiary Hospital in The Gambia, 2020-2023

Background and Aim

Cerebral malaria in Gambian children has been studied but there is limited information on CM in adults. The study assesses the clinical features and outcome of CM in adult patients admitted at the Edward Francis Small Teaching Hospital.

Method

This was a retrospective review of all adult patients with malaria admitted to the internal medicine department from October 18, 2020 to February 2, 2022.

Results

A total number of 319 adults were admitted with malaria. Eighty (25%) patients met the criteria for CM. The median age of the CM patients was 19 years. CM patients were younger (p < 0.001), more likely to be of the adolescent age group (p < 0.001), more likely to be referred from a lower-level health facility (p < 0.001), and more likely to be admitted in intensive care p < 0.001) as compared to NSCM or UM patients. The total in-hospital mortality of CM patients was 23.8%. Ten (52.6%) out of the 19 patients died within the first 24 h of admission. In multivariate analysis, CM patients with acute kidney injury at presentation was an independent predictor of mortality in this study.

Conclusion

CM seems to affect the adolescent age group more than the older adults in The Gambia. The clinicians should be able to identify these high-risk patient group and institute prompt critical care interventions and/or treatment. The findings in this study also identify the need to expand access of critical care interventions and hemodialysis to help improve the prognosis of adult CM patients in The Gambia.

Multiple Organ Dysfunction Syndrome in Malawian Children with Cerebral Malaria

More than 1,000 children under 5 years of age die every day from malaria. Cerebral malaria (CM) is the most severe and deadly manifestation of the disease. The occurrence of multiple organ dysfunction syndrome (MODS) has been associated with increased mortality in adult patients with CM. However, little is known about the frequency and severity of MODS in children with CM. This was a retrospective study of 199 pediatric patients with CM admitted to a referral hospital in Blantyre, Malawi, between January 2019 and May 2023. Data were abstracted from charts to calculate scores using four established scoring systems: Pediatric Logistic Organ Dysfunction-2 (PELOD-2), Pediatric Sequential Organ Failure Assessment (pSOFA), Signs of Inflammation in Children that Can Kill (SICK), and Lambaréné Organ Dysfunction Score (LODS). Mortality was 16% (n = 32). All four scoring systems were predictive of mortality, but the PELOD-2 and pSOFA scores outperformed the others with area under the curve values of 0.75 and 0.67, respectively. Multiple organ dysfunction syndrome was diagnosed in 182 patients (91%) using the PELOD-2 score, 172 patients (86%) using the pSOFA score, 99 patients (50%) using the SICK score, and 30 patients (15%) using the LODS. The PELOD-2 and pSOFA identify MODS in children with CM but require laboratory-based testing that is often unavailable in malaria-endemic areas. Furthermore, these scoring systems may identify primary malarial disease pathology rather than true organ dysfunction. Simplified scoring systems designed to recognize and quantify MODS in this patient population may provide opportunities for improved resource allocation and timely, organ-specific treatment.

Severe falciparum malaria in young children is associated with an increased risk of post-discharge hospitalization: a prospective cohort study

BACKGROUND

Few studies have described post-discharge morbidity of children with specific manifestations of severe malaria (SM) beyond severe malarial anaemia or cerebral malaria.

METHODS

Children 6 months to 4 years of age admitted at Jinja and Mulago hospitals in Uganda, with one or more of the five most common forms of SM, cerebral malaria (n = 53), respiratory distress syndrome (n = 108), malaria with complicated seizures (n = 160), severe malarial anaemia (n = 155) or prostration (n = 75), were followed for 12 months after discharge, alongside asymptomatic community children (CC) (n = 120) of similar ages recruited from the households or neighbourhoods of the children with SM. Incidence and risk of hospitalizations, death or outpatient clinic visits were compared between children with SM and CC.

RESULTS

312/551 (56.6%) of children with SM had one or more post-discharge hospitalization over 12 months, compared to 37/120 (30.8%) of CC. Frequency of hospitalization was similar across all forms of SM. Compared to CC, children with SM had a significantly higher risk of all-cause hospitalization (adjusted hazard ratio (aHR) 1.91, 95% confidence interval (CI) 1.39-2.63, p < 0.001) and hospitalization for severe malaria (aHR 1.94, CI 1.36-2.78, p < 0.001), but a similar risk of outpatient clinic visits for malaria (aHR 1.24, 95% CI 0.89-1.73, p = 0.20). 82% of hospitalizations in children with SM (575/700) and CC (50/61) were due to malaria.

CONCLUSIONS

In this malaria endemic region, children with the five most common forms of SM had higher rates of post-discharge hospitalization than asymptomatic community children, and > 80% of hospitalizations were due to severe malaria. Studies of post-discharge malaria chemoprevention are urgently needed for children with SM, to determine if this treatment can reduce post-discharge morbidity.

Delayed-Onset White Matter Lesions on Brain MRI in Recurrent Non-cerebral Plasmodium falciparum Imported Malaria Without Neurological Symptoms

Plasmodium falciparum malaria affects millions of people in certain regions of the world, with neurological involvement and/or cerebral malaria as potential manifestations. Brain magnetic resonance imaging (MRI) abnormalities have been well-documented in cerebral malaria. However, MRI abnormalities in non-cerebral malaria, especially in neurologically asymptomatic patients, are not well understood and have been less frequently reported, especially in non-endemic regions. Additionally, there are no known studies that observe and analyze the presence and progression of these radiological abnormalities over long periods. Here, we present the case of a patient with recurrent non-cerebral imported malaria infections spanning two decades. Despite a normal brain MRI three years prior, the patient was found to have extensive subcortical white matter fluid-attenuated inversion recovery abnormalities on MRI. This case highlights the possibility that even neurologically subclinical malaria infections can result in significant, long-standing brain changes, raising important questions about the pathophysiology of malaria's effects on the brain, the potential for cumulative neurological damage over time, and the clinical significance of such findings. In addition, the significance of the location of these lesions in non-cerebral cases remains unclear, particularly in terms of their clinical implications and reversibility. Our findings suggest the need for further studies to evaluate the long-term consequences of malaria infections on the brain, particularly in non-cerebral cases, and to explore whether these radiological abnormalities are reversible or lead to lasting neurological impairment.

Genome Editing in Apicomplexan Parasites: Current Status, Challenges, and Future Possibilities

Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) technology has revolutionized genome editing across various biological systems, including the Apicomplexa phylum. This review describes the status, challenges, and applications of CRISPR-Cas9 editing technology in apicomplexan parasites, such as Plasmodium, Toxoplasma, Theileria, Babesia, and Cryptosporidium. The discussion encompasses successfully implemented CRISPR-Cas9-based techniques in these parasites, highlighting the achieved milestones, from precise gene modifications to genome-wide screening. In addition, the review addresses the challenges hampering efficient genome editing, including the parasites' complex life cycles, multiple intracellular stages, and the lack of robust genetic tools. It further explores the ethical and policy considerations surrounding genome editing and the future perspectives of CRISPR-Cas applications in apicomplexan parasites.

Role of Nitric oxide synthase II in cognitive impairment due to experimental cerebral malaria

The role of nitric oxide (NO) in the pathogenesis of cerebral malaria and its cognitive sequelae remains controversial. Cerebral malaria is still the worst complication of Plasmodium falciparum infection, which is characterized by high rates of morbidity and mortality. Even after recovery from infection due to antimalarial therapy, the development of cognitive impairment in survivors reinforces the need to seek new therapies that demonstrate efficacy in preventing long-lasting sequelae. During disease pathogenesis, reactive oxygen and nitrogen species (RONS) are produced after the established intense inflammatory response. Increased expression of the enzyme inducible nitric oxide synthase (iNOS) seems to contribute to tissue injury and the onset of neurological damage. Elevated levels of NO developed by iNOS can induce the production of highly harmful nitrogen-reactive intermediates such as peroxynitrite. To address this, we performed biochemical and behavioral studies in C57BL6 mice, aminoguanidine (specific pharmacological inhibitor of the enzyme iNOS) treated and iNOS-/-, infected with Plasmodium berghei ANKA (PbA), with the aim of clarifying the impact of iNOS on the pathogenesis of cerebral malaria. Our findings underscore the effectiveness of both strategies in reducing cerebral malaria and providing protection against the cognitive impairment associated with the disease. Here, the absence or blockade of the iNOS enzyme was effective in reducing the signs of cerebral malaria detected after six days of infection. This was accompanied by a decrease in the production of pro-inflammatory cytokines and reactive oxygen and nitrogen species. In addition, nitrotyrosine (NT-3), a marker of nitrosative stress, was also reduced. Futher, cognitive dysfunction was analyzed fifteen days after infection in animals rescued from infection by chloroquine treatment (25 mg/kg bw). We observed that both interventions on the iNOS enzyme were able to improve memory and learning loss in mice. In summary, our data suggest that the iNOS enzyme has the potential to serve as a therapeutic target to prevent cognitive sequelae of cerebral malaria.

Contribution of Magnetic Resonance Imaging Studies to the Understanding of Cerebral Malaria Pathogenesis

Cerebral malaria (CM), the most lethal clinical syndrome of Plasmodium falciparum infection, mostly affects children under 5 in sub-Saharan Africa. CM is characterized by seizures and impaired consciousness that lead to death in 15-20% of cases if treated quickly, but it is completely fatal when untreated. Brain magnetic resonance imaging (MRI) is an invaluable source of information on the pathophysiology of brain damage, but, due to limited access to scanners in endemic regions, only until very recently have case reports of CM patients studied with advanced MRI methods been published. The murine model of experimental cerebral malaria (ECM) shares many common features with the human disease and has been extensively used to study the pathogenic mechanisms of the neurological syndrome. In vivo MRI studies on this model, the first of which was published in 2005, have contributed to a better understanding of brain lesion formation in CM and identified disease markers that were confirmed by MRI studies published from 2013 onwards in pediatric patients from endemic areas. In this review, we recapitulate the main findings and critically discuss the contributions of MRI studies in the ECM model to the understanding of human CM.

Severe Malaria in Angola: The Clinical Profile and Disease Outcome Among Adults from a Low-Endemic Area

BACKGROUND/OBJECTIVES

Severe malaria poses a significant public health concern in Angola, particularly among adults. This study assessed the clinical manifestations and outcomes of severe Plasmodium falciparum malaria in adult patients admitted to Hospital Central Dr. António Agostinho Neto of Lubango (HCL), Angola.

METHODS

The study retrospectively reviewed medical records of patients over 14 years old admitted with severe malaria during the first quarter of 2021 and 2022, coinciding with the peak transmission season. The World Health Organization (WHO) criteria were used to clarify the disease severity. The cohort included 640 patients-167 in 2021 and 473 in 2022-distributed across the following departments: the Intensive Care Unit (ICU; n = 81), Medicine (MED; n = 458) and Infectiology (INF; n = 101).

RESULTS

The median age was 26 years and 59.4% were males. Renal impairment was the most frequent severe manifestation, affecting 37.4% of cases. The mortality rate across the study period was 7%, showing a notable decrease from 10.2% in 2021 to 5.9% in 2022. The higher mortality rate in 2021 may reflect the impact of the COVID-19 pandemic, which limited hospital access and delayed care, resulting in more critical cases being admitted at a later stage. In 2022, with reduced COVID-19 pressures, earlier access to treatment may have improved outcomes, contributing to the lower mortality rate.

CONCLUSIONS

This study emphasizes the need to assess the clinical burden of severe malaria in low-endemic regions, where shifting patterns may signal emerging threats such as antimalarial drug resistance. Further research is essential to optimize control strategies and strengthen surveillance systems, reducing morbidity and mortality.

Severe falciparum malaria in young children is associated with an increased risk of post-discharge readmission or death: A prospective cohort study

Introduction

Few studies have described post-discharge morbidity of children with specific manifestations of severe malaria (SM) beyond severe malarial anemia or cerebral malaria.

Methods

Children 6 months to 4 years of age admitted at Jinja and Mulago hospitals in Uganda, with one or more of the five most common manifestations of SM, cerebral malaria (n=53), respiratory distress syndrome (n=108), malaria with complicated seizures (n=160), severe malarial anemia (n=155) or prostration (n=75), were followed for 12 months after discharge, along with community children (CC) (n=120) recruited from the household or neighborhood of the children with SM. Incidence and risk of post-discharge readmission, death or outpatient clinic visits were compared between children with SM and CC.

Results

312/551 (56.6%) of children with SM had one or more post-discharge readmission, compared to 37/120 (30.8%, p<0.001) of CC. Frequency of readmission was similar across all forms of SM. Compared to CC, children with SM had significantly higher risk of post-discharge readmission or death (adjusted hazard ratio (aHR) 2.06, 95% confidence interval (CI) 1.51-2.81, p<0.001), but a similar risk of outpatient malaria (aHR 1.30, 95% CI 0.97-1.74, p=0.08). 82% of readmissions in children with SM were due to malaria.

Conclusions

In this malaria endemic region, children with the most common forms of SM had higher rates of post-discharge readmission or death than CC, and >80% of readmissions were due to malaria. Studies of post-discharge malaria chemoprevention are urgently needed for children with SM, to determine if this treatment can reduce post-discharge morbidity and mortality.

Prevalence and factors associated with cerebral malaria among children aged 6 to 59 months with severe malaria in Western Uganda: a hospital-based cross-sectional study

INTRODUCTION

Cerebral malaria, caused by Plasmodium falciparum, represents the most severe neurologic complication of malaria. Its association with high morbidity and mortality rates, especially among young children, underscores its clinical significance. In sub-Saharan Africa, including Uganda, cerebral malaria remains a major health challenge, contributing significantly to the high child mortality rate. Despite advances in malaria control, the burden of cerebral malaria among children under five is substantial, reflecting the need for targeted interventions and improved management strategies. This study aimed to determine the prevalence of cerebral malaria and identify associated factors among children admitted with severe malaria at a tertiary hospital in western Uganda.

METHODS

This was a cross-sectional, descriptive, and analytical study involving children aged 6 to 59 months admitted with severe malaria. The study was conducted from January to March 2023 at Fort Portal Regional Referral Hospital. Severe and cerebral malaria were defined as per the WHO criteria. Sociodemographic, clinical, and laboratory data were collected and analyzed using IBM SPSS version 27. Logistic regression analysis was used to evaluate the factors associated with cerebral malaria. A p-value < 0.05 indicated statistical significance.

RESULTS

A total of 250 children were recruited (mean age 33.1 ± 17.3 months). The prevalence of cerebral malaria was 12.8% (95% CI: 8.9-17.6). Cerebral malaria was independently associated with male sex (aOR: 3.05, 95% CI: 1.20-7.77, p = 0.02), abnormal bleeding (aOR: 13.22, 95% CI: 11.54-15.16, p = 0.001), history of convulsions (aOR 12.20, 95% CI: 10.7-21.69, p = 0.010), acute kidney injury (aOR: 4.50, 95% CI: 1.30-15.53, p = 0.02), and hyponatremia (aOR: 3.47, 95% CI: 1.34-8.96, p = 0.010).

CONCLUSIONS AND RECOMMENDATIONS

The prevalence of cerebral malaria was high among children with severe malaria. Factors associated with cerebral malaria included male gender, history of convulsions, abnormal bleeding, acute kidney injury, and hyponatremia. Targeted interventions and early management are essential to improve clinical outcomes.

Hemozoin induces malaria via activation of DNA damage, p38 MAPK and neurodegenerative pathways in a human iPSC-derived neuronal model of cerebral malaria

Malaria caused by Plasmodium falciparum infection results in severe complications including cerebral malaria (CM), in which approximately 30% of patients end up with neurological sequelae. Sparse in vitro cell culture-based experimental models which recapitulate the molecular basis of CM in humans has impeded progress in our understanding of its etiology. This study employed healthy human induced pluripotent stem cells (iPSCs)-derived neuronal cultures stimulated with hemozoin (HMZ) - the malarial toxin as a model for CM. Secretome, qRT-PCR, Metascape, and KEGG pathway analyses were conducted to assess elevated proteins, genes, and pathways. Neuronal cultures treated with HMZ showed enhanced secretion of interferon-gamma (IFN-γ), interleukin (IL)1-beta (IL-1β), IL-8 and IL-16. Enrichment analysis revealed malaria, positive regulation of cytokine production and positive regulation of mitogen-activated protein kinase (MAPK) cascade which confirm inflammatory response to HMZ exposure. KEGG assessment revealed up-regulation of malaria, MAPK and neurodegenerative diseases-associated pathways which corroborates findings from previous studies. Additionally, HMZ induced DNA damage in neurons. This study has unveiled that exposure of neuronal cultures to HMZ, activates molecules and pathways similar to those observed in CM and neurodegenerative diseases. Furthermore, our model is an alternative to rodent experimental models of CM.

Nucleic acid sensing in the central nervous system: Implications for neural circuit development, function, and degeneration

Nucleic acids are a critical trigger for the innate immune response to infection, wherein pathogen-derived RNA and DNA are sensed by nucleic acid sensing receptors. This subsequently drives the production of type I interferon and other inflammatory cytokines to combat infection. While the system is designed such that these receptors should specifically recognize pathogen-derived nucleic acids, it is now clear that self-derived RNA and DNA can also stimulate these receptors to cause aberrant inflammation and autoimmune disease. Intriguingly, similar pathways are now emerging in the central nervous system in neurons and glial cells. As in the periphery, these signaling pathways are active in neurons and glia to present the spread of pathogens in the CNS. They further appear to be active even under steady conditions to regulate neuronal development and function, and they can become activated aberrantly during disease to propagate neuroinflammation and neurodegeneration. Here, we review the emerging new roles for nucleic acid sensing mechanisms in the CNS and raise open questions that we are poised to explore in the future.

Sudden Onset of Coma and Fulminant Progression to Brain Death in a 48-Year-Old Male With Cerebral Malaria

Cerebral malaria is the most severe complication of Plasmodium falciparum infection. Left untreated, it is universally fatal. Coma is the clinical hallmark, emerging between the first and third days of fever. Adults typically present with mild cerebral edema, usually with a more favorable prognosis compared to the pediatric population. We present a case of a 48-year-old man with a recent travel to Angola who presented comatose on the second day of a febrile illness with clinical signs of cerebral herniation and diffuse cerebral edema and cerebellar tonsil ectopia on cranioencephalic computed tomography. He had a missed diagnosis on a first visit to the emergency department 2 days prior. The diagnosis of cerebral malaria was confirmed after the identification of the parasite in peripheral blood. He was admitted to an intensive care unit; however, progression to brain death was inevitable within a few hours. Malaria affects 5% of the world's population. In Portugal, it has an incidence of 0.01 in every 1000 inhabitants, and all cases are imported. Despite its rarity in a nonendemic country, its severity alerts to the consideration of this syndrome in the etiologic workup of coma. The early recognition of the diagnosis is of major importance for the establishment of definitive treatment, as its timely administration has a crucial impact on the outcome.

Falciparum malaria with haemorrhagic stroke in a 26-year male patient: report of a rare case

BACKGROUND

Malaria continues to cause unacceptably high levels of disease and death despite increased global efforts and is still significant public health problem. African countries are disproportionately affected by malaria. The objective of this study was to describe a rare case of haemorrhagic stroke as a possible complication of malaria in a 26-year-old male patient.

CASE PRESENTATION

A 26-year-old male from southwest Ethiopia presented with complaint of loss of consciousness (LOC) of 12 h duration. He had fever, headache, vomiting, chills, rigors and shivering three days prior to the loss of consciousness. On physical examination, pulse rate 116 beats/min, blood pressure of 120/90 mmHg, respiratory rate was 24 breaths/min, a temperature of 38.9◦C and oxygen saturation of 94%. Nervous system examination; stuporous with Glasgow Coma Scale (GCS) 10/15(M5, E3, V2). Blood film and RDT confirmed a Plasmodium falciparum infection and a non-contrast CT scan found a right cerebral parenchymal haemorrhage.

DISCUSSION AND CONCLUSION

The presented case described a very rare case of a 26-year-old male patient who was diagnosed with left side hemiparesis secondary to a haemorrhagic stroke, associated with P. falciparum malaria. This report highlights the fact that malaria with stroke should be considered a differential diagnosis in a patient presenting with body weakness in a malaria endemic area and in individuals who had travel history to malaria endemic areas.

Admission Point-of-Care Testing for the Clinical Care of Children with Cerebral Malaria

Point-of-care testing (PoCT), an alternative to laboratory-based testing, may be useful in the clinical care of critically ill children in resource-limited settings. We evaluated the clinical utility of PoCT in the care of 193 Malawian children treated for World Health Organization-defined cerebral malaria (CM) between March 2019 and May 2023. We assessed the frequency of abnormal PoCT results and the clinical interventions performed in response to these abnormalities. We determined the association between abnormal PoCT results and patient outcomes. Overall, 52.1% of all PoCT results were abnormal. Of the children with abnormal results, clinical interventions occurred in 16.9%. Interventions most commonly followed abnormal results for PoCT glucose (100.0% of the patients had treatment for hypoglycemia), potassium (32.1%), lactate (22.0%), and creatinine (16.3%). Patients with hypoglycemia, hyperlactatemia, and hypocalcemia had a higher mortality risk than children with normal values. Future studies are needed to determine whether obtaining laboratory values using PoCT and the clinical response to these interventions modify outcomes in critically ill African children with CM.

A morphological and molecular approach to investigating infectious disease in early medieval Iberia: The necropolis of La Olmeda (Palencia, Spain)

OBJECTIVE

Here we investigate infectious diseases that potentially contribute to osteological lesions in individuals from the early medieval necropolis of La Olmeda (6th-11th c. CE) in North Iberia.

MATERIALS AND METHODS

We studied a minimum number of 268 individuals (33 adult females; 38 adult males, 77 unknown/indeterminate sex; and 120 non-adults), including articulated and commingled remains. Individuals with differential diagnoses suggesting chronic systemic infectious diseases were sampled and bioinformatically screened for ancient pathogen DNA.

RESULTS

Five non-adults (and no adults) presented skeletal evidence of chronic systemic infectious disease (1.87% of the population; 4.67% of non-adults). The preferred diagnoses for these individuals included tuberculosis, brucellosis, and malaria. Ancient DNA fragments assigned to the malaria-causing pathogen, Plasmodium spp., were identified in three of the five individuals. Observed pathology includes lesions generally consistent with malaria; however, additional lesions in two of the individuals may represent hitherto unknown variation in the skeletal manifestation of this disease or co-infection with tuberculosis or brucellosis. Additionally, spondylolysis was observed in one individual with skeletal lesions suggestive of infectious disease.

CONCLUSIONS

This study sheds light on the pathological landscape in Iberia during a time of great social, demographic, and environmental change. Genetic evidence challenges the hypothesis that malaria was absent from early medieval Iberia and demonstrates the value of combining osteological and archaeogenetic methods. Additionally, all of the preferred infectious diagnoses for the individuals included in this study (malaria, tuberculosis, and brucellosis) could have contributed to the febrile cases described in historical sources from this time.

Understanding the pathogenic mechanisms and therapeutic effects in neurocysticercosis

Despite being a leading cause of acquired seizures in endemic regions, the pathological mechanisms of neurocysticercosis are still poorly understood. This study aims to investigate the impact of anthelmintic treatment on neuropathological features in a rat model of neurocysticercosis. Rats were intracranially infected with Taenia solium oncospheres and treated with albendazole + praziquantel (ABZ), oxfendazole + praziquantel (OXF), or untreated placebo (UT) for 7 days. Following the last dose of treatment, brain tissues were evaluated at 24 h and 2 months. We performed neuropathological assessment for cyst damage, perilesional brain inflammation, presence of axonal spheroids, and spongy changes. Both treatments showed comparable efficacy in cyst damage and inflammation. The presence of spongy change correlated with spheroids counts and were not affected by anthelmintic treatment. Compared to white matter, gray matter showed greater spongy change (91.7% vs. 21.4%, p < 0.0001), higher spheroids count (45.2 vs. 0.2, p = 0.0001), and increased inflammation (72.0% vs. 21.4%, p = 0.003). In this rat model, anthelmintic treatment destroyed brain parasitic cysts at the cost of local inflammation similar to what is described in human neurocysticercosis. Axonal spheroids and spongy changes as markers of damage were topographically correlated, and not affected by anthelmintic treatment.

Extracellular vesicles in malaria: Pathogenesis, diagnosis and therapy

Malaria is a life-threatening disease caused by parasites from the genus Plasmodium. Five species can cause malaria in humans, with Plasmodium vivax being the most common in many countries and Plasmodium falciparum having the highest lethality, which can lead to cerebral malaria. Extracellular vesicles (EVs) are in focus in malaria research to better understand pathogenesis, diagnosis, therapy, and prognosis. Malaria-causing parasites use EVs to transfer their molecules to host cells, a mechanism that significantly contributes to parasite survival and successful infection. EVs have thus emerged as an essential component of the immunopathological cascade of malaria, playing a pivotal role in disease progression and severity. This chapter discusses the epidemiology and pathogenesis of malaria and the role of EVs as new diagnostic and therapeutic tools, emphasizing their potential clinical significance.

A complex case of recurrent intracranial bleeds due to malaria-induced coagulopathy: A case report and literature review

Background

Malaria, a prevalent disease in the developing world, is a significant cause of morbidity and mortality. Infection with Plasmodium falciparum, although uncommon, can lead to severe brain injury, including intracranial hemorrhages, resulting in serious neurological deficits. Malaria-induced coagulopathy, while rarely reported, poses a challenge in understanding the exact mechanisms behind the development of intracranial bleeds. Proposed mechanisms include sequestration of parasitized erythrocytes in the brain's microvasculature, leading to capillary occlusion, endothelial damage, cytokine activation, and dysregulation of the coagulation cascade.

Case Description

We present the case of a 53-year-old male rapidly deteriorating following a history of traumatic brain injury (TBI). Upon admission, a computed tomography scan revealed bilateral acute on chronic hematomas, necessitating a lifesaving craniotomy. Subsequently, the patient experienced three consecutive recurrent intracranial bleeds post-surgery, attributed to Falciparum-induced coagulopathy. Prompt recognition and intervention stabilized the patient's condition, leading to discharge on the 4th post-operative day.

Conclusion

This case underscores the challenges posed by consecutive recurrent intracranial bleeds following TBI exacerbated by P. falciparum infection. It highlights the obstinate nature of malaria-induced coagulopathy and underscores the importance of timely and aggressive interventions in managing such cases.

The mRNA content of plasma extracellular vesicles provides a window into molecular processes in the brain during cerebral malaria

The impact of cerebral malaria on the transcriptional profiles of cerebral tissues is difficult to study using noninvasive approaches. We isolated plasma extracellular vesicles (EVs) from patients with cerebral malaria and community controls and sequenced their mRNA content. Deconvolution analysis revealed that EVs from cerebral malaria are enriched in transcripts of brain origin. We ordered the patients with cerebral malaria based on their EV-transcriptional profiles from cross-sectionally collected samples and inferred disease trajectory while using healthy community controls as a starting point. We found that neuronal transcripts in plasma EVs decreased with disease trajectory, whereas transcripts from glial, endothelial, and immune cells increased. Disease trajectory correlated positively with severity indicators like death and was associated with increased VEGFA-VEGFR and glutamatergic signaling, as well as platelet and neutrophil activation. These data suggest that brain tissue responses in cerebral malaria can be studied noninvasively using EVs circulating in peripheral blood.

Potential of extracellular vesicles in the pathogenesis, diagnosis and therapy for parasitic diseases

Parasitic diseases have a significant impact on human and animal health, representing a major hazard to the public and causing economic and health damage worldwide. Extracellular vesicles (EVs) have long been recognized as diagnostic and therapeutic tools but are now also known to be implicated in the natural history of parasitic diseases and host immune response modulation. Studies have shown that EVs play a role in parasitic disease development by interacting with parasites and communicating with other types of cells. This review highlights the most recent research on EVs and their role in several aspects of parasite-host interactions in five key parasitic diseases: Chagas disease, malaria, toxoplasmosis, leishmaniasis and helminthiases. We also discuss the potential use of EVs as diagnostic tools or treatment options for these infectious diseases.

Anesthetic approach to pregnant patients with malaria: a narrative review of the literature

INTRODUCTION

Anesthesiologists play an important role in the management of labor and delivery during acute malaria infection. The peripartum anesthesia considerations for such cases remain unclear.

FINDINGS

Important peripartum considerations include the severity of thrombocytopenia and coagulopathy, hemodynamic status and cardiac disease, and the likelihood of central nervous system (CNS) involvement. Several antimalarial drugs may interact with perioperative medications, causing hypoglycemia, methemoglobinemia, or QT prolongation. Labor should usually not be induced. Patient volume status should be optimized pre-induction, but fluids should be administered with caution given the risk of cerebral edema. In case of CNS involvement intracranial pressure should be maintained. Case reports describe the successful use of neuraxial anesthesia but this approach requires further confirmation of safety. Despite the risks accompanying airway management in pregnancy, in some cases, general anesthesia was preferred due to the chance of CNS infection and disease complications. Tight postoperative assessments of neurological and bleeding status are indicated regardless of the mode of delivery.

CONCLUSIONS

Despite the prevalence of malaria, the perioperative risk and preferred mode of anesthesia for pregnant patients with acute malaria remain under-researched and outcome data are limited.

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.

Apolipoprotein-E4: risk of severe malaria and mortality and cognitive impairment in pediatric cerebral malaria

BACKGROUND

The relationship of apolipoprotein-E4 (APOE4) to mortality and cognition after severe malaria in children is unknown.

METHODS

APOE genotyping was performed in children with cerebral malaria (CM, n = 261), severe malarial anemia (SMA, n = 224) and community children (CC, n = 213). Cognition was assessed over 2-year follow-up.

RESULTS

A greater proportion of children with CM or SMA than CC had APOE4 (n = 162, 31.0%; n = 142, 31.7%; n = 103, 24.2%, respectively, p = 0.02), but no difference was seen in APOE3 (n = 310, 59.4%; n = 267, 59.6%; n = 282, 66.2%, respectively, p = 0.06), or APOE2 (n = 50, 9.6%; n = 39, 8.7%; and n = 41, 9.6%, respectively, p = 0.87). APOE4 was associated with increased mortality in CM (odds ratio, 2.28; 95% CI, 1.01, 5.11). However, APOE4 was associated with better long-term cognition (ß, 0.55; 95% CI, 0.04, 1.07, p = 0.04) and attention (ß 0.78; 95% CI, 0.26, 1.30, p = 0.004) in children with CM < 5 years old, but worse attention (ß, -0.90; 95% CI, -1.69, -0.10, p = 0.03) in children with CM ≥ 5 years old. Among children with CM, risk of post-discharge malaria was increased with APOE4 and decreased with APOE3.

CONCLUSIONS

APOE4 is associated with higher risk of CM or SMA and mortality in children with CM, but better long-term cognition in CM survivors <5 years of age.

Vital Sign alterations within 24 hours prior to death in children with retinopathy-positive Cerebral Malaria at Queen Elizabeth Central Hospital Malawi

Background

Malaria is a significant obstacle to child health and survival. Plasmodium falciparum infections, especially in children under five, lead to high morbidity and mortality. Cerebral malaria (CM) is a life-threatening complication characterized by coma, and its diagnosis can be improved by observing malarial retinopathy in children. Monitoring vital signs is essential for managing patients with CM.

Objectives

To determine if changes in vital signs predict death in children with retinopathy positive cerebral malaria (RPCM).

Methods

This was a retrospective case-control study using data collected from children admitted to the Paediatric Research Ward at Queen Elizabeth Central Hospital in Blantyre between 1997 and 2020. Patients who died 24 hours or more after admission were matched with control patients who survived. Linear regression analyses were used to assess the differential time trends of each vital sign in the survivor group and death group. Classification models were used to quantify various vital signs' predictive power of death.

Results

Among the population that died, the estimated change in average respiratory rate per hour approaching death was 0.02 breaths per minute compared to -0.25 breaths per minute among those who survive (p < 0.001), and the estimated change in average BCS per hour approaching death was -0.01 compared to 0.06 among the survivors (p < 0.001). Changes in temperature and heart rate were not associated with clinical deterioration. Three models were developed, and the best receiver operating characteristic curve was 100% sensitive, the corresponding false positive rate was 75%.

Conclusion

Changes in respiratory rate and BCS have prognostic significance in the final 24 hours before death in children with cerebral malaria. Extra attention should be paid to these two vital signs as they may help to identify children who are at increased risk of deteriorating.

Severe malaria-related disability in Ethiopian children from the perspectives of caregivers: an interpretive description study

PURPOSE

This study explored severe malaria-related disability in children from the perspectives of their caregivers.

MATERIALS AND METHODS

The interpretive description qualitative approach was employed. The participants were selected using the purposive sampling technique considering the child's history of severe malaria, age (0-10 years), and location (urban/rural). Data were collected through face-to-face interviews with sixteen caregivers. Reflexive thematic data analysis was utilized. Through prolonged engagement, reflective journaling, an audit trail, and co-authors' review, trustworthiness was enhanced.

RESULTS

The study generated five themes from the interviews: mitigators of disability, contributors of disability, impact on body function, impact on activities and participation, and uncertainties about future well-being. The findings revealed previously unstudied social components of disability and environmental factors. Furthermore, the research uncovered health-related quality of life aspects that are out of the scope of the current comprehensive disability framework.

CONCLUSIONS

The study contributes to a deeper understanding of severe malaria-related disability in children from the biopsychosocial perspective. The findings could help policymakers, researchers, and clinicians who want to design rehabilitation interventions for the affected children or examine the components of disability on a large scale using quantitative methods.IMPLICATIONS FOR REHABILITATIONVarious contextual factors interacted with severe malaria and influenced functioning either as facilitators or barriers, implying disability related to malaria can be prevented or created.The long-term impacts of severe malaria are not limited to functioning and disability but also affect the health-related quality of life of children who survive severe malaria.Rehabilitation professionals should consider applying comprehensive functioning and disability frameworks such as the ICF when designing (or applying) screening tools, planning interventions, and evaluating the outcomes of intervention for children with severe malaria-related disability.Rehabilitation interventions for children with severe malaria-related disability should consider patient- or caregiver-reported outcomes (components of disability).

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.

Rapid diagnosis and prognosis of malaria infection using a microfluidic point-of-care immunoassay

Malaria is a major cause of illness and death worldwide. Rapid diagnostic tests are the most widely used tool for detecting malaria infection, however, they only provide binary results and lack the sensitivity needed to detect many asymptomatic infections. Molecular assays for quantifying malaria biomarkers offer higher detection sensitivity, however, they are time-consuming, and require expert training and expensive equipment, making them unsuitable for use in most of Africa. To address the need for simple, accurate and field-deployable malaria diagnostic tests, we have developed a microfluidic point-of-care (mPOC) immunoassay for rapid quantification of Plasmodium falciparum histidine-rich protein 2 (PfHRP2), a malaria parasite biomarker, in whole blood. This device features two diagnostic modes for detecting PfHRP2 at low (100's pg/mL) and high (1,000's ng/mL) concentrations, making it useful for multiple diagnostic applications, including the detection of asymptomatic infection, prediction of disease outcomes and diagnosis of cerebral malaria. Measurements of PfHRP2 in blood samples from malaria patients demonstrates that this platform offers similar accuracy as an ultra-sensitive PfHRP2 enzyme-linked immunosorbent assay (ELISA) test, while being 12× faster and simpler to use. This mPOC immunoassay can be deployed in rural health centers to assist clinicians in diagnosing and triaging malaria patients, ultimately improving patient outcomes.

Virus-Induced Epilepsy vs. Epilepsy Patients Acquiring Viral Infection: Unravelling the Complex Relationship for Precision Treatment

The intricate relationship between viruses and epilepsy involves a bidirectional interaction. Certain viruses can induce epilepsy by infecting the brain, leading to inflammation, damage, or abnormal electrical activity. Conversely, epilepsy patients may be more susceptible to viral infections due to factors, such as compromised immune systems, anticonvulsant drugs, or surgical interventions. Neuroinflammation, a common factor in both scenarios, exhibits onset, duration, intensity, and consequence variations. It can modulate epileptogenesis, increase seizure susceptibility, and impact anticonvulsant drug pharmacokinetics, immune system function, and brain physiology. Viral infections significantly impact the clinical management of epilepsy patients, necessitating a multidisciplinary approach encompassing diagnosis, prevention, and treatment of both conditions. We delved into the dual dynamics of viruses inducing epilepsy and epilepsy patients acquiring viruses, examining the unique features of each case. For virus-induced epilepsy, we specify virus types, elucidate mechanisms of epilepsy induction, emphasize neuroinflammation's impact, and analyze its effects on anticonvulsant drug pharmacokinetics. Conversely, in epilepsy patients acquiring viruses, we detail the acquired virus, its interaction with existing epilepsy, neuroinflammation effects, and changes in anticonvulsant drug pharmacokinetics. Understanding this interplay advances precision therapies for epilepsy during viral infections, providing mechanistic insights, identifying biomarkers and therapeutic targets, and supporting optimized dosing regimens. However, further studies are crucial to validate tools, discover new biomarkers and therapeutic targets, and evaluate targeted therapy safety and efficacy in diverse epilepsy and viral infection scenarios.

The Perpetual Vector Mosquito Threat and Its Eco-Friendly Nemeses

Mosquitoes are the most notorious arthropod vectors of viral and parasitic diseases for which approximately half the world's population, ~4,000,000,000, is at risk. Integrated pest management programs (IPMPs) have achieved some success in mitigating the regional transmission and persistence of these diseases. However, as many vector-borne diseases remain pervasive, it is obvious that IPMP successes have not been absolute in eradicating the threat imposed by mosquitoes. Moreover, the expanding mosquito geographic ranges caused by factors related to climate change and globalization (travel, trade, and migration), and the evolution of resistance to synthetic pesticides, present ongoing challenges to reducing or eliminating the local and global burden of these diseases, especially in economically and medically disadvantaged societies. Abatement strategies include the control of vector populations with synthetic pesticides and eco-friendly technologies. These "green" technologies include SIT, IIT, RIDL, CRISPR/Cas9 gene drive, and biological control that specifically targets the aquatic larval stages of mosquitoes. Regarding the latter, the most effective continues to be the widespread use of Lysinibacillus sphaericus (Ls) and Bacillus thuringiensis subsp. israelensis (Bti). Here, we present a review of the health issues elicited by vector mosquitoes, control strategies, and lastly, focus on the biology of Ls and Bti, with an emphasis on the latter, to which no resistance has been observed in the field.

Optic nerve sheath diameter and its association with brain swelling in pediatric cerebral malaria: a retrospective study

Introduction

Mortality in pediatric cerebral malaria (CM) in low- and middle-income countries (LMICs) is associated with brain swelling on magnetic resonance imaging (MRI); however, MRI is unavailable in most LMICs. Optic nerve sheath diameter (ONSD) measurement is an inexpensive method of detecting increased intracranial pressure compared with the invasive opening pressure (OP). Our primary objective was to determine if increased ONSD correlated with brain swelling on MRI in pediatric CM. Our secondary objective was to determine if increased ONSD correlated with increased OP and/or poor neurological outcome in pediatric CM. We hypothesized that increased ONSD would correlate with brain swelling on MRI and increased OP and that ONSD would be higher in survivors with sequelae and non-survivors.

Methods

We performed a retrospective chart review of children aged 0-12 years in Blantyre, Malawi, from 2013 to 2022 with CM as defined by the World Health Organization. Brain swelling on admission MRI was characterized by brain volume scores (BVS); severe swelling was scored as 7-8, mild-to-moderate as 4-6, normal as 3. The admission ONSD was measured via ultrasound; it was defined as abnormal if it was >4.5 mm in children >1 year and >4 mm in children <1 year. Favorable outcome was defined as a normal neurological exam on discharge in survivors. The primary and secondary objectives were evaluated using Spearman's correlation; and the demographics were compared using chi-square and the Kruskal-Wallis test (Stata, College Station, TX, USA).

Results

Median age of the 207-patients cohort was 50 months [interquartile range (IQR) 35-75]; 49% (n = 102) were female. Of those, 73% (n = 152) had a favorable outcome, and 14% (n = 30) died. Twenty-nine (14%) had a normal BVS, 134 (65%) had mild-to-moderate swelling, and 44 (21%) had severe swelling. ONSD was elevated in 86% (n = 178) of patients, while 12% of patients had increased OP. There was a weakly positive correlation between BVS and ONSD (r = 0.14, p = 0.05). The median ONSD was not significantly different compared by discharge outcome (p = 0.11) or by BVS (p = 0.18).

Conclusion

ONSD was not a reliable tool to correlate with BVS, neurological outcome, or OP in children with CM. Future studies to identify alternative methods of early identification of CM patients at highest risk for morbidity and mortality are urgently needed.

Exploring adjunctive therapies for cerebral malaria

Cerebral malaria (CM) is one of the most severe complications of malaria infection characterized by coma and neurological effects. Despite standardized treatment of malaria infection with artemisinin-based combination therapies (ACT), the mortality rate is still high, and it primarily affects pediatric patients. ACT reduces parasitemia but fails to adequately target the pathogenic mechanisms underlying CM, including blood-brain-barrier (BBB) disruption, endothelial activation/dysfunction, and hyperinflammation. The need for adjunctive therapies to specifically treat this form of severe malaria is critical as hundreds of thousands of people continue to die each year from this disease. Here we present a summary of some potential promising therapeutic targets and treatments for CM, as well as some that have been tested and deemed ineffective or, in some cases, even deleterious. Further exploration into these therapeutic agents is warranted to assess the effectiveness of these potential treatments for CM patients.

Discrete class I molecules on brain endothelium differentially regulate neuropathology in experimental cerebral malaria

Cerebral malaria is the deadliest complication that can arise from Plasmodium infection. CD8 T-cell engagement of brain vasculature is a putative mechanism of neuropathology in cerebral malaria. To define contributions of brain endothelial cell major histocompatibility complex (MHC) class I antigen-presentation to CD8 T cells in establishing cerebral malaria pathology, we developed novel H-2Kb LoxP and H-2Db LoxP mice crossed with Cdh5-Cre mice to achieve targeted deletion of discrete class I molecules, specifically from brain endothelium. This strategy allowed us to avoid off-target effects on iron homeostasis and class I-like molecules, which are known to perturb Plasmodium infection. This is the first endothelial-specific ablation of individual class-I molecules enabling us to interrogate these molecular interactions. In these studies, we interrogated human and mouse transcriptomics data to compare antigen presentation capacity during cerebral malaria. Using the Plasmodium berghei ANKA model of experimental cerebral malaria (ECM), we observed that H-2Kb and H-2Db class I molecules regulate distinct patterns of disease onset, CD8 T-cell infiltration, targeted cell death and regional blood-brain barrier disruption. Strikingly, ablation of either molecule from brain endothelial cells resulted in reduced CD8 T-cell activation, attenuated T-cell interaction with brain vasculature, lessened targeted cell death, preserved blood-brain barrier integrity and prevention of ECM and the death of the animal. We were able to show that these events were brain-specific through the use of parabiosis and created the novel technique of dual small animal MRI to simultaneously scan conjoined parabionts during infection. These data demonstrate that interactions of CD8 T cells with discrete MHC class I molecules on brain endothelium differentially regulate development of ECM neuropathology. Therefore, targeting MHC class I interactions therapeutically may hold potential for treatment of cases of severe malaria.

Updated Anopheles mosquitos abundance and distribution in north-eastern malaria-free area of Argentina

Malaria is the most important parasitic disease worldwide. In 2019, more than 679,441 cases of malaria were reported in the American region. During this study, Argentina was in malaria pre-elimination autochthonous transmission phase with the aim of being declared as malaria-free country. The aim of this work was to assess the influence of remote sensing spectral indices (NDVI, NDWI) and climatic variables (temperature, relative humidity and precipitation) on the distribution and abundance of Anopheles mosquitoes, in four localities with different degrees of anthropogenic disturbance and with previous malaria cases records located , in a historical malarious area in northeastern of Argentina. Between June 2012 and July 2014, mosquitoes were collected. We collected 535 Anopheles adult mosquitoes. Anopheles strodei s.l. was the most abundant species. The greatest richness, diversity and abundance of species were registered in wild and semi-urban environments. The abundance of Anopheles presented a negative association with relative humidity and mean temperature, but positive with mean maximum temperature. The most important variables determining Anopheles total abundance and distribution were NDWI Index and distance to vegetation. The abundance of An. strodei s.l., was positive associated with water areas whereas the NDVI Index was negatively associated.

Bradykinin produced during Plasmodium falciparum erythrocytic cycle drives monocyte adhesion to human brain microvascular endothelial cells

Cerebral malaria (CM) pathogenesis is described as a multistep mechanism. In this context, monocytes have been implicated in CM pathogenesis by increasing the sequestration of infected red blood cells to the brain microvasculature. In disease, endothelial activation is followed by reduced monocyte rolling and increased adhesion. Nowadays, an important challenge is to identify potential pro-inflammatory stimuli that can modulate monocytes behavior. Our group have demonstrated that bradykinin (BK), a pro-inflammatory peptide involved in CM, is generated during the erythrocytic cycle of P. falciparum and is detected in culture supernatant (conditioned medium). Herein we investigated the role of BK in the adhesion of monocytes to endothelial cells of blood brain barrier (BBB). To address this issue human monocytic cell line (THP-1) and human brain microvascular endothelial cells (hBMECs) were used. It was observed that 20% conditioned medium from P. falciparum infected erythrocytes (Pf-iRBC sup) increased the adhesion of THP-1 cells to hBMECs. This effect was mediated by BK through the activation of B2 and B1 receptors and involves the increase in ICAM-1 expression in THP-1 cells. Additionally, it was observed that angiotensin-converting enzyme (ACE) inhibitor, captopril, enhanced the effect of both BK and Pf-iRBC sup on THP-1 adhesion. Together these data show that BK, generated during the erythrocytic cycle of P. falciparum, could play an important role in adhesion of monocytes in endothelial cells lining the BBB.

Pattern of Clinical and Laboratory Presentation of Cerebral Malaria among Children in Nigeria

Introduction

Cerebral malaria (CM) is the most lethal form of severe malaria with high case fatality rates. Overtime, there is an inherent risk in changing pattern of presentation of CM which, if the diagnosis is missed due to these changing factors, may portend a poor outcome. Variations in the pattern of clinic-laboratory presentations also make generalization difficult. This study was, therefore, set out to report the pattern of clinical and laboratory presentation of CM.

Methods

This was a cross-sectional study among children aged 6 months to 14 years admitted with a diagnosis of CM as defined by the World Health Organization criteria. A pretested pro forma was filled, and detailed neurological examination and laboratory (biochemical, microbiology, and hematology) investigations were done. P <5% was considered statistically significant.

Results

Sixty-four children were recruited with a mean age of 34.9 ± 24.9 months and a male-to-female ratio of 1.9:1. There were 87.5% of under-five children. Fever (96.9%) was the major presenting feature closely followed by convulsions (92.2%). Convulsions were mainly generalized (94.9%) and multiple (76.5%). Profound coma (Blantyre coma score of 0) was present in 12.5% of cases, and the leading features on examination were fever (84.4%) and pallor (75.0%). Retinal vessel whitening (48.4%) was the most common funduscopic abnormality. Metabolic acidosis (47.9%), severe anemia (14.1%), hyperglycemia (17.2%), and hypoglycemia (7.8%) were seen among the children. Few (1.6%) had hyperparasitemia and bacteremia (3.2%).

Conclusion

Early recognition of the clinical presentation and prompt management may improve the outcome of cerebral malaria.

PARACENTRAL ACUTE MIDDLE MACULOPATHY ASSOCIATED WITH SEVERE PLASMODIUM FALCIPARUM MALARIA

PURPOSE

To report a case of bilateral paracentral acute middle maculopathy lesions on spectral domain-optical coherence tomography(OCT) secondary to severe Plasmodium falciparum malaria.

METHODS

Retrospective case report. Spectral domain-OCT, ultra-widefield fluorescein angiography, and OCT angiography were performed and analyzed.

RESULTS

A 54-year-old healthy man presented with acute vision loss in both eyes few days after being diagnosed with severe Plasmodium falciparum malaria. Ophthalmoscopic examination was unremarkable, but near-infrared reflectance imaging showed patchy hyporeflective areas located at the terminal tips of the venous branches. Corresponding spectral-domain OCT demonstrated alternating bands of hyperreflectivity involving the inner nuclear layer, consistent with skip paracentral acute middle maculopathy lesions. Optical coherance tomography angiography illustrated corresponding flow signal loss at the level of the deep capillary plexus. Ultra-widefield fluorescein angiography showed peripheral retinal vein staining and capillary nonperfusion.

CONCLUSION

Paracentral acute middle maculopathy may be an OCT manifestation of malarial retinopathy associated with severe Plasmodium falciparum infection.

TNFR1 signaling converging on FGF14 controls neuronal hyperactivity and sickness behavior in experimental cerebral malaria

BACKGROUND

Excess tumor necrosis factor (TNF) is implicated in the pathogenesis of hyperinflammatory experimental cerebral malaria (eCM), including gliosis, increased levels of fibrin(ogen) in the brain, behavioral changes, and mortality. However, the role of TNF in eCM within the brain parenchyma, particularly directly on neurons, remains underdefined. Here, we investigate electrophysiological consequences of eCM on neuronal excitability and cell signaling mechanisms that contribute to observed phenotypes.

METHODS

The split-luciferase complementation assay (LCA) was used to investigate cell signaling mechanisms downstream of tumor necrosis factor receptor 1 (TNFR1) that could contribute to changes in neuronal excitability in eCM. Whole-cell patch-clamp electrophysiology was performed in brain slices from eCM mice to elucidate consequences of infection on CA1 pyramidal neuron excitability and cell signaling mechanisms that contribute to observed phenotypes. Involvement of identified signaling molecules in mediating behavioral changes and sickness behavior observed in eCM were investigated in vivo using genetic silencing.

RESULTS

Exploring signaling mechanisms that underlie TNF-induced effects on neuronal excitability, we found that the complex assembly of fibroblast growth factor 14 (FGF14) and the voltage-gated Na+ (Nav) channel 1.6 (Nav1.6) is increased upon tumor necrosis factor receptor 1 (TNFR1) stimulation via Janus Kinase 2 (JAK2). On account of the dependency of hyperinflammatory experimental cerebral malaria (eCM) on TNF, we performed patch-clamp studies in slices from eCM mice and showed that Plasmodium chabaudi infection augments Nav1.6 channel conductance of CA1 pyramidal neurons through the TNFR1-JAK2-FGF14-Nav1.6 signaling network, which leads to hyperexcitability. Hyperexcitability of CA1 pyramidal neurons caused by infection was mitigated via an anti-TNF antibody and genetic silencing of FGF14 in CA1. Furthermore, knockdown of FGF14 in CA1 reduced sickness behavior caused by infection.

CONCLUSIONS

FGF14 may represent a therapeutic target for mitigating consequences of TNF-mediated neuroinflammation.

Cerebral Metabolic Crisis in Pediatric Cerebral Malaria

Cerebral metabolic energy crisis (CMEC), often defined as a cerebrospinal fluid (CSF) lactate: pyruvate ratio (LPR) >40, occurs in various diseases and is associated with poor neurologic outcomes. Cerebral malaria (CM) causes significant mortality and neurodisability in children worldwide. Multiple factors that could lead to CMEC are plausible in these patients, but its frequency has not been explored. Fifty-three children with CM were enrolled and underwent analysis of CSF lactate and pyruvate levels. All 53 patients met criteria for a CMEC (median CSF LPR of 72.9 [interquartile range [IQR]: 58.5-93.3]). Half of children met criteria for an ischemic CMEC (median LPR of 85 [IQR: 73-184]) and half met criteria for a nonischemic CMEC (median LPR of 60 [IQR: 54-79]. Children also underwent transcranial doppler ultrasound investigation. Cerebral blood flow velocities were more likely to meet diagnostic criteria for low flow (<2 standard deviation from normal) or vasospasm in children with an ischemic CMEC (73%) than in children with a nonischemic CMEC (20%, p  = 0.04). Children with an ischemic CMEC had poorer outcomes (pediatric cerebral performance category of 3-6) than those with a nonischemic CMEC (46 vs. 22%, p  = 0.03). CMEC was ubiquitous in this patient population and the processes underlying the two subtypes (ischemic and nonischemic) may represent targets for future adjunctive therapies.

Dynamic intravital imaging reveals reactive vessel-associated microglia play a protective role in cerebral malaria coagulopathy

Vascular congestion and coagulopathy have been shown to play a role in human and experimental cerebral malaria (eCM), but little is known about the role of microglia, or microglia-vascular interactions and hypercoagulation during disease progression in this fatal infection. Recent studies show microglia bind to fibrinogen, a glycoprotein involved in thrombosis. An eCM model of Plasmodium chabaudi infection in mice deficient in the regulatory cytokine IL-10 manifests neuropathology, including hypercoagulation with extensive fibrin(ogen) deposition and neuroinflammation. Intravital microscopy and immunofluorescence are applied to elucidate the role of microglia in eCM. Results show microgliosis and coagulopathy occur early in disease at 3 dpi (day post-infection), and both are exacerbated as disease progresses to 7dpi. Vessel associated microglia increase significantly at 7 dpi, and the expression of the microglial chemoattractant CCL5 (RANTES) is increased versus uninfected and localized with fibrin(ogen) in vessels. PLX3397 microglia depletion resulted in rapid behavioral decline, severe hypothermia, and greater increase in vascular coagulopathy. This study suggests that microglia play a prominent role in controlling infection-initiated coagulopathy and supports a model in which microglia play a protective role in cerebral malaria by migrating to and patrolling the cerebral vasculature, potentially regulating degree of coagulation during systemic inflammation.