Neurological Complications of Malaria

Computer Viewing Model for Classification of Erythrocytes Infected with Plasmodium spp. Applied to Malaria Diagnosis Using Optical Microscope

Background and Objectives: Malaria is a disease that can result in a variety of complications. Diagnosis is carried out by an optical microscope and depends on operator experience. The use of artificial intelligence to identify morphological patterns in erythrocytes would improve our diagnostic capability. The object of this study was therefore to establish computer viewing models able to classify blood cells infected with Plasmodium spp. to support malaria diagnosis by optical microscope. Materials and Methods: A total of 27,558 images of human blood sample extensions were obtained from a public data bank for analysis; half were of parasite-infected red cells (n = 13,779), and the other half were of uninfected erythrocytes (n = 13,779). Six models (five machine learning algorithms and one pre-trained for a convolutional neural network) were assessed, and the performance of each was measured using metrics like accuracy (A), precision (P), recall, F1 score, and area under the curve (AUC). Results: The model with the best performance was VGG-19, with an AUC of 98%, accuracy of 93%, precision of 92%, recall of 94%, and F1 score of 93%. Conclusions: Based on the results, we propose a convolutional neural network model (VGG-19) for malaria diagnosis that can be applied in low-complexity laboratories thanks to its ease of implementation and high predictive performance.

The role of periostin (OSF-2) in the cytoadherence phenomena mediated by malaria parasites

Introduction

The pathogenesis of severe malaria is primarily attributed to the cytoadherence properties of Plasmodium-infected erythrocytes (IRBC), which include rosetting and IRBC-endothelial cytoadherence. These cytoadherence events are influenced by various parasite- and host-derived factors. Previously, antibodies against human periostin (OSF-2), an inflammation-associated protein, were reported to inhibit rosetting. In this study, we aimed to characterize the OSF-2-mediated cytoadherence in infections caused by Plasmodium falciparum (the most fatal human malaria parasite) and P. knowlesi (an emerging, potentially fatal zoonotic malaria parasite).

Methods

Laboratory-adapted P. falciparum and P. knowlesi isolates were cultured, and the late-stage parasites were purified for experiments using recombinant human OSF-2.

Results

We found that OSF-2 at a concentration of 200 ng/ml induced rosette-stimulation in both parasite species. Furthermore, we demonstrated the serum dependency of OSF-2-mediated rosetting. The rosette-stimulating effect of OSF-2 was completely abolished when IRBC were treated with a low concentration of trypsin. This suggests a role for P. falciparum erythrocyte membrane protein 1 (PfEMP1) in OSF-2-mediated rosetting by P. falciparum, and reveals the trypsin-sensitive nature of the P. knowlesi-derived ligands involved in OSF-2-mediated rosetting. We also found that OSF-2-mediated rosetting was independent of the ABO blood group. Additionally, we demonstrated the ability of OSF-2 to disrupt the IRBC-endothelial binding.

Discussion

This work contributes to our understanding of the host-parasite interactions in malaria pathobiology.

From Bench to Bedside: Unraveling Cerebral Malaria and Malarial Retinopathy by Combining Clinical and Pre-Clinical Perspectives

Infection with Plasmodium falciparum carries a significant risk of cerebral malaria (CM). Children are particularly susceptible to human CM (HCM) which manifests as an acute neurovascular encephalopathy leading to high levels of mortality. Occurring in parallel with CM, malarial retinopathy (MR) is readily detected on ophthalmoscopy as one or more of: white-centered retinal hemorrhage, retinal whitening, and vessel discoloration. It leads to several distinct types of blood retinal barrier (BRB) breakdown. The precise molecular mechanisms underpinning CM and MR remain ill-defined, but parasitemia is known to drive progressive neurovascular obstruction and inflammation leading to cerebral and retinal edema and ischemia. Extensive clinical studies in patients with CM have shown that retinal examination is a useful approach for understanding pathology and an indicator for risk of mortality and morbidity. Fully understanding the cellular and molecular mechanisms that underpin CM and MR is important for developing new therapeutic approaches and in this regard the murine model of experimental CM (ECM) has proved to offer considerable value. Much is known about brain pathology in this model although much less is understood about the retina. In this review, we seek to evaluate MR in clinical scenarios and make comparisons with the retina from mice with ECM. Through detailed in vivo and post-mortem studies in the mouse and human retina, this review highlights the links between CM and MR and how this will aid our understanding of the disease progression and pathogenesis.

Stroke from Infection

BACKGROUND

Stroke related to infections represents a less common but significant cause, particularly in low- and middle-income countries. This review examines the pathophysiology of stroke from infections, involving both direct and indirect mechanisms.

SUMMARY

Bacterial infections such as tuberculous meningitis and infective endocarditis can directly cause strokes through local inflammation, arteritis, and septic embolism. Viral infections like Varicella zoster virus and HIV increase stroke risk through chronic immune activation, vasculopathy, and endothelial dysfunction. Parasitic infections, particularly malaria and neurocysticercosis, can cause strokes via vascular occlusion and inflammatory responses. Fungal infections like aspergillosis and mucormycosis can lead to strokes through vasculitis and direct invasion of the CNS.

KEY MESSAGES

Understanding the mechanisms by which various infectious agents contribute to stroke pathogenesis is essential for developing targeted therapeutic strategies and improving patient outcomes. Further research is needed to establish effective prevention and treatment for infection-related strokes, especially in low- and middle-income countries.

Vitamin C co-administration with artemether-lumefantrine abrogates chronic stress exacerbated Plasmodium berghei-induced sickness behaviour, inflammatory and oxidative stress responses in mice

This study evaluated the effects of vitamin C and artemether-lumefantrine (AL) on sickness behaviour and oxido-inflammatory response in chronically stressed mice infected with Plasmodium berghei. Sickness behaviour severity was examined with weight and assessment of mice behaviours. Results showed that stress increased parasitaemia in infected mice. Vitamin C co-administration with AL increased parasite clearance over AL alone, and modulated inflammatory cytokines (TNF-α, IL-1β, IL-10, IL-12) and antioxidant parameters in plasma and brain tissue. Conclusively, stress worsens malaria-induced sickness behaviour and up-regulates the inflammatory and oxidative stress response. Co-administration of vitamin C with AL appears to counteract these detrimental effects.

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.

Post-infectious central nervous system vasculitides in adults: an underdiagnosed and treatable disease : Part I. Overview

INTRODUCTION

The differential diagnosis of Primary Central Nervous System Angiitis (PACNS) is complex and includes several inflammatory and non-inflammatory conditions. Among the first ones, post-infectious CNS vasculitides represent a relevant topic and they are often underdiagnosed.

AIMS

The main aim of this review is to summarize the clinical and neuroimaging features of post-infectious vasculitides, highlighting the diagnostic clues and the need to carefully consider them in the differential diagnosis of PACNS.

FINDINGS

Several infectious agents (viruses, bacteria, fungi and parasites) can be involved in documented post-infectious vasculitides, often with a pathological confirmation. Post-infectious vasculitides involve not only immunocompromised hosts but also immunocompetent people and the diagnosis might be complicated by the lack of close time relationship between infections and neuro-logical symptoms, as in Varicella Zoster Virus (VZV) related vasculopathy in adults. Several complications may occur, ranging from ischemic to hemorrhagic stroke, from arterial to venous thrombosis, from large to small vessel involvement, often simultaneously.

CONCLUSIONS

Post-infectious vasculitides are caused by a broad spectrum of microorganisms and they should be carefully considered in the differential diagnosis of some neurological pictures and neuroradiologicals findings in immunocompetent adults too.

Plasma Soluble Progenitor Cell Receptors as Biomarkers for Severe Anemia Among Malaria-Infected Pediatrics: A Prospective Study in Ghana

Background

Soluble forms of progenitor cell receptors may be implicated in the delayed erythropoietic response during severe anemia. In this study, plasma levels of soluble erythropoietin receptor (sEPO-R) and soluble granulocyte, macrophage-colony stimulating factor receptor (sGM-CSFR) were assessed in Plasmodium falciparum-infected children in Ghana.

Methods

This case-control study was conducted at Tamale Teaching Hospital, Ghana. One hundred and twenty P. falciparum-infected, and 60 uninfected children aged 12-144 months were recruited from April to July, 2023. About 4 mL of blood was collected for malaria microscopy, full blood count using a haematology analyser, and sEPO-R, sGM-CSFR and erythropoietin (EPO) estimation using enzyme-linked immunosorbent assays. Data were analyzed using SPSS version 26.0.

Results

Plasma levels of sEPO-R were higher among participants with severe malarial anemia (SMA) than those in the non-SMA and control groups (p < 0.001). Plasma sGM-CSFR levels were higher in P. falciparum-infected children than in controls, but the levels were similar between the SMA and non-SMA groups. Hemoglobin (r = -0.823, p < 0.001), RBC (r = -0.852, p < 0.001), HCT (r = -0.790, p < 0.001) and platelets (r = -0.810, p < 0.001) negatively correlated with sEPO-R. There was a strong positive correlation between sEPO-R and EPO in P. falciparum-infected children (r = 0.901, p < 0.001). Plasma sEPO-R better predicted severe anemia among malaria-infected children (cut-off point: 161.5 pg/mL, sensitivity: 96.0%, specificity: 82.9%, AUC: 0.964, p < 0.001).

Conclusion

P. falciparum-infected children had higher plasma levels of sGM-CSFR, sEPO-R and EPO. Plasma sEPO-R correlated negatively with erythrocyte parameters, suggesting a possible contribution of the endogenous receptor to the development of severe anemia in children with malaria. Further studies to investigate the neutralizing effects of sEPO-R on erythropoietic response during malaria are recommended.

Post-malaria delayed cerebellar ataxia in a traveller

An Italian traveller returning from Kenya was diagnosed and treated for malaria. Fourteen days later, he developed cerebellar symptoms and was diagnosed with delayed cerebellar ataxia (DCA), a rare, self-limiting post-malarial neurological complication with a favourable prognosis that may appear after effectively treated malaria.

Variability of day-to-day pulsatility index change in children with cerebral malaria

Introduction

Cerebral malaria (CM) is a devastating disease and better understanding of etiologies of the resulting neurologic injury is needed. The purpose of this study is to describe the day-to-day (DTD) pulsatility index (PI) change measured by transcranial Doppler ultrasound (TCD), a novel measure of cerebral and vascular changes, in children with CM.

Methods

A retrospective analysis of 122 children in sub-Saharan Africa with CM and 3 or more sequential TCD measurements was performed. Variability of DTD PI change was calculated as a measure of changes in vasculature overtime. Neurologic outcome was determined by the Pediatric Cerebral Performance Category (PCPC) score, a measure of neurologic function.

Results

Of the 122 participants, 77.9% had a good neurologic outcome (no neurologic sequelae), and 22.1% had a poor outcome (neurologic sequelae or died). Patients who had a poor neurologic outcome had higher levels of variability of DTD PI change in the right middle cerebral artery (MCA) (0.14 ± 0.21) and left MCA (0.17 ± 0.41) compared to those who had a good neurologic outcome (0.1 ± 0.1 and 0.11 ± 0.19, respectively). A higher variability of both left and right MCA DTD PI change was also associated with higher brain volume assessed through neuroimaging.

Discussion

Variability of DTD PI change may provide early prognostic information regarding PCPC outcomes and brain volume changes seen in CM patients. Expanded research on pathophysiologic contributors to variability of DTD PI changes in children with CM is warranted.

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.

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.

Profile and Determinants for Complications of Imported Malaria in 5 Chinese Provinces From 2014 to 2021: Retrospective Analysis

Background

In 2021, the World Health Organization officially declared the People's Republic of China as malaria-free. However, despite this milestone achievement, the continued occurrence of severe and fatal cases of imported malaria in China, due to globalization and increased international communication, remains a significant public health concern.

Objective

The aim of this study was to elucidate the epidemiological characteristics of imported malaria in 5 Chinese provinces from 2014 to 2021 and to identify the factors that influence complications in imported malaria cases. The findings will provide a basis for enhancing prevention and control measures, thereby consolidating China's achievements in malaria elimination.

Methods

A case-based retrospective study was performed, using surveillance data collected from the representative provinces of China from 2014 to 2021. Epidemiological characteristics were analyzed using descriptive statistics. Logistic regression was used to identify the factors influencing the occurrence of complications.

Results

A total of 5559 malaria cases were included during the study period. The predominant species was Plasmodium falciparum (3940/5559, 70.9%), followed by Plasmodium ovale (1054/5559, 19%), Plasmodium vivax (407/5559, 7.3%), Plasmodium malariae (157/5559, 2.8%), and 1 case of Plasmodium knowlesi. Most of the cases were male (5343/5559, 96.1%). The complication rates for P falciparum and P ovale were 11.4% and 3.3%, respectively. Multivariate logistic regression analysis of the relevant factors of malaria complications revealed potential protective factors, including a previous infection by Plasmodium (P<.001; odds ratio [OR] 0.512, 95% CI 0.422-0.621), and risk factors, including increased age (P=.004; OR 1.014, 95% CI 1.004-1.024), misdiagnosis at the first clinical visit (P<.001; OR 3.553, 95% CI 2.886-4.375), and the time interval from onset to treatment (P=.001; OR 1.026, 95% CI 1.011-1.042). Subgroup analyses identified risk factors associated with P falciparum, which include advanced age (P=.004; OR 1.015, 95% CI 1.005-1.026), initial misdiagnosis during the first clinical visit (P<.001; OR 3.549, 95% CI 2.827-4.455), the time interval from onset to treatment (P<.001; OR 1.043, 95% CI 1.022-1.063), and a delay of more than 3 days from the first treatment to diagnosis (P<.001; OR 2.403, 95% CI 1.823-3.164). Additionally, the risk factors pertaining to P ovale involve misdiagnosis at the initial clinical visit (P=.01; OR 2.901, 95% CI 1.336-6.298), the time interval from onset to treatment (P=.002; OR 1.095, 95% CI 1.033-1.160), and the duration from the initial treatment to diagnosis (P=.43; OR 1.032, 95% CI 0.953-1.118). Previous infections can prevent the progression of both P falciparum and P ovale.

Conclusions

This study showed that the increasing proportion of P ovale in recent years should not be ignored. Furthermore, there is a need to improve diagnostic awareness, enhance the capacity of medical institutions, and provide health education for high-risk groups.

M. S, N. SN, Shankar G, Tripathi PK, Kashyap H, Jain A, Anvikar A, Chalageri VH. Exploring the hidden mental health consequences of malaria beyond the fever

Malaria morbidity has various presentations and the focus now shifts to uncommon signs and symptoms of malaria infection such as cognitive impairment to address the morbidity when the mortality declines. About 50% of children admitted to hospitals due to malaria experience neurological complications due to factors like low blood sugar, inflammation, elevated pressure, decreased oxygen levels, and excitotoxicity. Malaria during pregnancy negatively also impacts children's cognitive, behavioral, and executive function leading to neurodevelopmental delay due to increased susceptibility which can significantly affect maternal and child health, leading to higher rates of underestimated factors like anxiety, depression, and PTSD. Despite having the world's second-largest tribal population, India's indigenous and tribal communities and their mental health are less explored and less understood. Western psychological tools and neurocognitive assessment tools are not universally applicable, thus necessitating the development of tailored tools to investigate psychological or neurocognitive impairment. This paper has illuminated the hidden mental health consequences of malaria infection, emphasizing the prevalence, nature, and implications of psychological distress among affected individuals. The findings underscore the importance of recognizing and addressing these psychological consequences in the holistic management and prevention of malaria and its mental health consequences.

Cerebral malaria presenting as nonconvulsive status epilepticus: a case report

BACKGROUND

Malaria is an infectious malady caused by Plasmodium parasites, cerebral malaria standing out as one of its most severe complications. Clinical manifestation include elevated body temperature, loss of consciousness, and seizures. However, reports of cerebral malaria presenting as nonconvulsive status epilepticus are extremely rare. The case presented involves psychiatric symptoms, with the electroencephalogram indicated nonconvulsive status epilepticus associated with cerebral malaria.

CASE PRESENTATION

A 53-year-old male, was urgently admitted, due to confusion and abnormal behaviour for 10 h. The patient returned to China after developing a fever while working in Tanzania two months ago. The blood smear revealed Plasmodium vivax and Plasmodium falciparum, and he was diagnosed with malaria. He recovered following anti-malarial treatment. After admission, the patient was confused, unable to communicate normally, and unwilling to cooperate with the physical examination. Plasmodium was not found in the blood smear, but the DNA sequence of P. falciparum was discovered using metagenomic next-generation sequencing of cerebrospinal fluid. Brain MRI revealed no significant abnormalities. Continuous electroencephalogram monitoring revealed that the patient had non-convulsive status epilepticus, which was treated with diazepam and levetiracetam. The patient had normal consciousness and behaviour. He received anti-malarial treatment for two weeks and fully recovered.

CONCLUSIONS

This case demonstrates that nonconvulsive status epilepticus can be a manifestation of cerebral malaria. It is imperative for attending physicians to heighten vigilance when encountering patients with a history of travel to malaria-endemic regions or a prior malaria infection, especially in the presence of unusual clinical presentations.

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 the malaria related GND. The aim of this systematic review is to synthesize evidence on the prevalence and risk factors for GND in children following CM and map the changes in patterns over time. In addition, this review will synthesize evidence on the reported prevalence and risk factors of gross neurologic deficits following other forms of 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, then at full text for inclusion using a priori eligibility criteria. Data extraction will be done using a tool developed and optimized in Excel spreadsheet. Risk of bias assessment will be done using appropriate tools including ROBINS-E ('Risk Of Bias In Non-randomized Studies of Exposure') tool, while publication bias will be assessed using funnel plot. A random-effects meta-analysis and structured narrative synthesis of the outcomes will be performed and results presented.

Discussion

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

Systematic review registration

The protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO), registration number CRD42022297109.

Enhanced Antimalarial and Antisequestration Activity of Methoxybenzenesulfonate-Modified Biopolymers and Nanoparticles for Tackling Severe Malaria

Severe malaria is a life-threatening condition that is associated with a high mortality. Severe Plasmodium falciparum infections are mediated primarily by high parasitemia and binding of infected red blood cells (iRBCs) to the blood vessel endothelial layer, a process known as sequestration. Here, we show that including the 5-amino-2-methoxybenzenesulfonate (AMBS) chemical modification in soluble biopolymers (polyglutamic acid and heparin) and poly(acrylic acid)-exposing nanoparticles serves as a universal tool to introduce a potent parasite invasion inhibitory function in these materials. Importantly, the modification did not add or eliminated (for heparin) undesired anticoagulation activity. The materials protected RBCs from invasion by various parasite strains, employing both major entry pathways. Two further P. falciparum strains, which either expose ligands for chondroitin sulfate A (CSA) or intercellular adhesion molecule 1 (ICAM-1) on iRBCs, were tested in antisequestration assays due to their relevance in placental and cerebral malaria, respectively. Antisequestration activity was found to be more efficacious with nanoparticles vs gold-standard soluble biopolymers (CSA and heparin) against both strains, when tested on receptor-coated dishes. The nanoparticles also efficiently inhibited and reversed the sequestration of iRBCs on endothelial cells. First, the materials described herein have the potential to reduce the parasite burden by acting at the key multiplication stage of reinvasion. Second, the antisequestration ability could help remove iRBCs from the blood vessel endothelium, which could otherwise cause vessel obstruction, which in turn can lead to multiple organ failure in severe malaria infections. This approach represents a further step toward creation of adjunctive therapies for this devastating condition to reduce morbidity and mortality.

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.

Epidemiological shifts: the emergence of malaria in America

Plasmodium is a genus of parasites that comprises different species. The species falciparum, vivax, malariae, ovale, and knowlesi are known to cause a vector-borne illness called malaria, and among these, falciparum is known to cause major complications. The vector, the Anopheles mosquito, is commonly found in warmer regions close to the equator, and hence transmission and numbers of cases tend to be higher in Sub-Saharan Africa, South Asia, and Central America. The number of cases of malaria in the United States has remained stable over the years with low transmission rates, and the disease is mostly seen in the population with a recent travel history to endemic regions. The main reason behind this besides the weather conditions is that economically developed countries have eliminated mosquitos. However, there have been reports of locally reported cases with Plasmodium vivax in areas such as Florida and Texas in patients with no known travel history. This paper aims to familiarize US physicians with the pathophysiology, clinical features, and diagnostic modalities of malaria, as well as available treatment options.

Knobs, Adhesion, and Severe Falciparum Malaria

Plasmodium falciparum can cause a severe disease with high mortality. A major factor contributing to the increased virulence of P. falciparum, as compared to other human malarial parasites, is the sequestration of infected erythrocytes in the capillary beds of organs and tissues. This sequestration is due to the cytoadherence of infected erythrocytes to endothelial cells. Cytoadherence is primarily mediated by a parasite protein expressed on the surface of the infected erythrocyte called P. falciparum erythrocyte membrane protein-1 (PfEMP1). PfEMP1 is embedded in electron-dense protuberances on the surface of the infected erythrocytes called knobs. These knobs are assembled on the erythrocyte membrane via exported parasite proteins, and the knobs function as focal points for the cytoadherence of infected erythrocytes to endothelial cells. PfEMP1 is a member of the var gene family, and there are approximately 60 antigenically distinct PfEMP1 alleles per parasite genome. Var gene expression exhibits allelic exclusion, with only a single allele being expressed by an individual parasite. This results in sequential waves of antigenically distinct infected erythrocytes and this antigenic variation allows the parasite to establish long-term chronic infections. A wide range of endothelial cell receptors can bind to the various PfEMP1 alleles, and thus, antigenic variation also results in a change in the cytoadherence phenotype. The cytoadherence phenotype may result in infected erythrocytes sequestering in different tissues and this difference in sequestration may explain the wide range of possible clinical manifestations associated with severe falciparum malaria.

Posterior Reversible Leucoencephalopathy Syndrome: Case Series, Comments, and Diagnostic Dilemma

PURPOSE OF REVIEW

To report a series of patients with clinical and radiological features suggestive of posterior reversible encephalopathy syndrome (PRES) related to diverse etiologies emphasizing its pathophysiological basis.

RECENT FINDINGS

Posterior reversible encephalopathy syndrome (PRES) may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury induced by ischemia from a vasoconstrictive response to rising blood pressure or toxins/cytokines. While clinical and radiographic reversibility is common, long-standing morbidity and mortality can occur in severe forms. In patients with malignant forms of PRES, aggressive care has markedly reduced mortality and improved functional outcomes. Various factors that have been associated with poor outcome include altered sensorium, hypertensive etiology, hyperglycemia, longer time to control the causative factor, elevated C reactive protein, coagulopathy, extensive cerebral edema, and hemorrhage on imaging. Reversible cerebral vasoconstriction syndromes (RCVS) and primary angiitis of the central nervous system (PACNS) are invariably considered in the differential diagnosis of new cerebral arteriopathies. Recurrent thunderclap headache (TCH), and single TCH combined with either normal neuroimaging, border zone infarcts, or vasogenic edema, have 100% positive predictive value for diagnosing RCVS or RCVS-spectrum disorders. Diagnosis of PRES in some circumstances can be challenging and structural imaging may not be sufficient to distinguish it from other differential diagnostic considerations like ADEM. Advanced imaging techniques, such as MR spectroscopy or positron emission tomography (PET) can provide additional information to determine the diagnosis. Such techniques are more useful to understand the underlying vasculopathic changes in PRES and may answer some of the unresolved controversies in pathophysiology of this complex disease. Eight patients with PRES resulting from different etiologies varying from pre-eclampsia/eclampsia, post-partum headache with seizures, neuropsychiatric systemic lupus erythematosus, snake bite, Dengue fever with encephalopathy, alcoholic liver cirrhosis with hepatic encephalopathy, and lastly reversible cerebral vasoconstriction syndrome (RCVS). Additionally, a diagnostic dilemma between PRES and acute disseminated encephalomyelitis (ADEM) was notable in one patient. Some of these patients did not have or only very transiently had arterial hypertension. PRES may underlie the clinical conundrum of headache, confusion, altered sensorium, seizures, and visual impairment. PRES need not necessarily be always associated with high blood pressure. Imaging findings may also be variable. Both clinicians and radiologists need to familiarize themselves with such variabilities.

Vitamin C-rich juice co-administration with artemether-lumefantrine ameliorates oxido-inflammatory responses in Plasmodium berghei-infected mice

This study investigated the effects of co-administration of a commercial juice rich in vitamin C (Vit C) on the antimalarial efficacy of artemether-lumefantrine (AL) in Plasmodium berghei-infected mice. Fifty Balb/c mice were infected with Plasmodium berghei NK65 strain from a donor mouse. Parasitemia was established after 72 h. Animals were grouped into 6 (n = 10) and treated daily for 3 days with normal saline, chloroquine, artemether-lumefantrine (AL), AL plus 50% commercial juice (CJ), and AL plus 50% Vit C supplementation in drinks ad libitum, respectively. Body weight, parasitemia levels, and mean survival time were determined. Tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), nitrite, malondialdehyde, reduced glutathione (GSH), catalase, and superoxide dismutase (SOD) were determined in the serum and liver tissues. Spleen histopathological changes were determined by H&E staining. Parasitemia was cleared by administration of AL and was not affected by Vit C and CJ supplementation. Vit C significantly prevented body weight reduction in AL-treated mice. CJ and Vit C supplementation to AL-treated mice significantly improved survival proportion compared with AL alone animals. Vit C and CJ supplementation significantly improved reduction of TNF-α, IL-6, and malondialdehyde, and increased GSH, CAT, and SOD in AL-treated mice. Spleen cell degeneration and presence of malaria pigment were reduced in AL-treated animals. The results suggest that ad libitum co-administration of commercial juice and vitamin C with artemether-lumefantrine does not impair its antimalarial efficacy but rather improved antioxidant and anti-inflammatory effects in mice.

From the immune system to mood disorders especially induced by Toxoplasma gondii: CD4+ T cell as a bridge

Toxoplasma gondii (T. gondii), a ubiquitous and obligatory intracellular protozoa, not only alters peripheral immune status, but crosses the blood-brain barrier to trigger brain parenchymal injury and central neuroinflammation to establish latent cerebral infection in humans and other vertebrates. Recent findings underscore the strong correlation between alterations in the peripheral and central immune environment and mood disorders. Th17 and Th1 cells are important pro-inflammatory cells that can drive the pathology of mood disorders by promoting neuroinflammation. As opposed to Th17 and Th1, regulatory T cells have inhibitory inflammatory and neuroprotective functions that can ameliorate mood disorders. T. gondii induces neuroinflammation, which can be mediated by CD4+ T cells (such as Tregs, Th17, Th1, and Th2). Though the pathophysiology and treatment of mood disorder have been currently studied, emerging evidence points to unique role of CD4+ T cells in mood disorder, especially those caused by T. gondii infection. In this review, we explore some recent studies that extend our understanding of the relationship between mood disorders and T. gondii.