Inter-relationships of cardinal features and outcomes of symptomatic pediatric Plasmodium falciparum MALARIA in 1,933 children in Kampala, Uganda

Practice patterns in pediatric infectious encephalopathy in four centers in Africa

Introduction

Infectious encephalopathy (IE), including meningitis, infectious encephalitis, and cerebral abscess, remains prevalent and carries high mortality and morbidity in children, especially in low and middle income countries (LMIC). This study aims to describe the usual care and outcomes of pediatric IE in four LMIC hospitals in sub-Saharan Africa to support evidence-based care guideline development.

Methods

This is a secondary analysis of the Prevalence of Acute Critical Neurological disease in children: A Global Epidemiological Assessment-Developing Countries study, a 4-week, prospective, observational study in children (1 week to 17 years) with IE presenting to referral hospitals in Ethiopia, Kenya, Rwanda, and Ghana. Data collection included diagnostic testing, interventions, and patient outcomes [e.g., mortality, Pediatric Cerebral and Overall Performance Category Scores (PCPC and POPC)].

Results

Seventy-two children with IE were enrolled. Most patients were diagnosed with undifferentiated IE (78%, n = 56). Specific etiologies included cerebral malaria (10%, n = 7), viral encephalitis (4%, n = 3), tuberculosis (4%, n = 3), bacterial meningitis (3%, n = 2), and cerebral abscess (1%, n = 1). Fourteen patients (20%) had a head computed tomography performed. Thirty two (44%) children had a lumbar puncture but only 9 samples (28%) were sent for culture. Median time from diagnosis to antimicrobial therapy was 3 h (IQR 1-12 h). Half (51%, n = 33) of inpatients received intracranial pressure (ICP)-directed treatment but none underwent ICP monitoring. Mortality was 13% (n = 9). The percentage of children with a favorable cognitive score decreased from 95% (n = 62) prior to admission to 80% (n = 52) and 77% (n = 50) at discharge for PCPC and POPC respectively.

Discussion

IE led to considerable morbidity and mortality in this cohort, and evaluation and management varied across the care continuum. Resource limitations and diagnostic constraints may have affected diagnosis-directed therapy and other aspects of management. Further studies are needed to describe the epidemiology and management of IE in LMICs to inform future treatment protocols, the role of technological and human capacity building to support both basic monitoring and interventions, as well as creative new solutions to emergency and critical care in these settings.

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

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

Severe malaria burden, clinical spectrum and outcomes at Apac district hospital, Uganda: a retrospective study of routine health facility-based data

BACKGROUND

Most data describing severe malaria (SM) in sub-Saharan Africa (SSA) are from research settings outside disease endemic areas. Using routinely collected data from Apac District Hospital, this study aimed at determining the burden and clinical spectrum of severe malaria.

METHODS

This was a retrospective study that reviewed all paediatric admission records for malaria in the 24 months period from Jan 2019 to Dec 2020 at Apac District Hospital. Data on children aged 60 days to 12 years who at admission tested positive for malaria and fulfilled the World Health Organization clinical criteria for surveillance of severe malaria were abstracted using a customized proforma designed to capture variables on social demographic, clinical presentation, treatment, and outcomes. In addition, the tool included laboratory variables for complete blood counts, haemoglobin, and glucose levels. Data were analysed using STATA V15.0. The study had ethical approval from Mbale Regional Referral Hospital REC, Approval No. MRRH-REC 053/2019.

RESULTS

A total of 5631 admission records were retrieved for this study period. Of these, 3649 (64.8%) were malaria admissions and 3422/3649 were children below 12years, with only 1864 (54.5%) of children having complete data. Of the 1864 children, 745 (40.0%) fulfilled the severe malaria inclusion criteria. Of the 745 children, 51.4% (n = 381) were males. The median age at admission was 31 months (IQR = 17-60). The most common clinical presentations among children with severe malaria were fever 722 (97.3%), cough 478 (64.2%), and difficulty in breathing 122 (17.9%). The median length of hospital stay was 2 (IQR; 2-4) days and 133 (17.9%) had prolonged hospital stay (> 4 days). Factors independently associated with prolonged hospital stay were, presenting with difficulty in breathing, aOR 1.83 (95% CI 1.02-3.27, P = 0.042) and prostration aOR 8.47 (95% CI 1.94-36.99, P = 0.004). A majority of admitted children, 735 (98.7%) survived, while 10 (1.3%) died of SM.

CONCLUSION

A high proportion (40.0%) of malaria admissions were due to SM. Prolonged Hospital stay was associated with prostration and difficulty in breathing. Overall mortality was low, 1.3% compared to mortality in the previously reported series. This study was able to use routinely collected data to describe the burden and clinical spectrum of SM. Improvement in the quality of data from such settings would improve disease descriptions for policy, monitoring of epidemics, response to interventions and to inform research.

Estimating the burden of severe malarial anaemia and access to hospital care in East Africa

Severe malarial anaemia can be fatal if not promptly treated. Hospital studies may under-represent the true burden because cases often occur in settings with poor access to healthcare. We estimate the relationship of community prevalence of malaria infection and severe malarial anaemia with the incidence of severe malarial anaemia cases in hospital, using survey data from 21 countries and hospital data from Kenya, Tanzania and Uganda. The estimated percentage of severe malarial anaemia cases that were hospitalised is low and consistent for Kenya (21% (95% CrI: 7%, 47%)), Tanzania (18% (95% CrI: 5%, 52%)) and Uganda (23% (95% CrI: 9%, 48%)). The majority of severe malarial anaemia cases remain in the community, with the consequent public health burden being contingent upon the severity of these cases. Alongside health system strengthening, research to better understand the spectrum of disease associated with severe malarial anaemia cases in the community is a priority.

Entire Expressed Peripheral Blood Transcriptome in Pediatric Severe Malarial Anemia

This study on severe malarial anemia (SMA: Hb < 6.0 g/dL), a leading global cause of childhood morbidity and mortality, analyzed the entire expressed transcriptome in whole blood from children with non-SMA (Hb ≥ 6.0 g/dL, n = 41) and SMA (n = 25). Analyses revealed 3,420 up-regulated and 3,442 down-regulated transcripts, signifying impairments in host inflammasome activation, cell death, innate immune responses, and cellular stress responses in SMA. Immune cell profiling showed a decreased antigenic and immune priming response in children with SMA, favoring polarization toward cellular proliferation and repair. Enrichment analysis further identified altered neutrophil and autophagy-related processes, consistent with neutrophil degranulation and altered ubiquitination and proteasome degradation. Pathway analyses highlighted SMA-related alterations in cellular homeostasis, signaling, response to environmental cues, and cellular and immune stress responses. Validation with a qRT-PCR array showed strong concordance with the sequencing data. These findings identify key molecular themes in SMA pathogenesis, providing potential targets for new malaria therapies.

Genetic variations in human ATP2B4 gene alter Plasmodium falciparum in vitro growth in RBCs from Gambian adults

BACKGROUND

Polymorphisms in ATP2B4 coding for PMCA4b, the primary regulator of erythrocyte calcium concentration, have been shown by GWAS and cross-sectional studies to protect against severe malaria but the mechanism remains unknown.

METHODS

Using a recall-by-genotype design, we investigated the impact of a common haplotype variant in ATP2B4 using in vitro assays that model erythrocyte stage malaria pathogenesis. Ninety-six donors representing homozygote (carriers of the minor allele, C/C), heterozygote (T/C) and wildtype (T/T) carriers of the tagging SNP rs1541252 were selected from a cohort of over 12,000 participants in the Keneba Biobank.

RESULTS

Red blood cells (RBCs) from homozygotes showed reduced PMCA4b protein expression (mean fluorescence intensities (MFI = 2428 ± 124, 3544 ± 159 and 4261 ± 283], for homozygotes, heterozygotes and wildtypes respectively, p < 0.0001) and slower rates of calcium expulsion (calcium t_½ ± SD = 4.7 ± 0.5, 1.8 ± 0.3 and 1.9 ± 0.4 min, p < 0.0001). Growth of a Plasmodium falciparum laboratory strain (FCR3) and two Gambian field isolates was decreased in RBCs from homozygotes compared to heterozygotes and wildtypes (p < 0.01). Genotype group did not affect parasite adhesion in vitro or var-gene expression in malaria-infected RBCs. Parasite growth was inhibited by a known inhibitor of PMCA4b, aurintricarboxylic acid (IC₅₀ = 122uM CI: 110-134) confirming its sensitivity to calcium channel blockade.

CONCLUSION

The data support the hypothesis that this ATP2B4 genotype, common in The Gambia and other malaria-endemic areas, protects against severe malaria through the suppression of parasitaemia during an infection. Reduction in parasite density plays a pivotal role in disease outcome by minimizing all aspects of malaria pathogenesis. Follow up studies are needed to further elucidate the mechanism of protection and to determine if this ATP2B4 genotype carries a fitness cost or increases susceptibility to other human disease.

Whole Blood Transfusion for Severe Malarial Anemia in a High Plasmodium falciparum Transmission Setting

BACKGROUND

Severe malaria resulting from Plasmodium falciparum infection is the leading parasitic cause of death in children worldwide, and severe malarial anemia (SMA) is the most common clinical presentation. The evidence in support of current blood transfusion guidelines for patients with SMA is limited.

METHODS

We conducted a retrospective cohort study of 911 hospitalized children with SMA in a holoendemic region of Zambia to examine the association of whole blood transfusion with in-hospital survival. Data were analyzed in adjusted logistic regression models using multiple imputation for missing data.

RESULTS

The median age of patients was 24 months (interquartile range, 16-30) and overall case fatality was 16%. Blood transfusion was associated with 35% reduced odds of death in children with SMA (odds ratio, 0.65; 95% confidence interval, .52-.81; P = .0002) corresponding to a number-needed-to-treat (NNT) of 14 patients. Children with SMA complicated by thrombocytopenia were more likely to benefit from transfusion than those without thrombocytopenia (NNT = 5). Longer storage time of whole blood was negatively associated with survival and with the posttransfusion rise in the platelet count but was not associated with the posttransfusion change in hemoglobin concentration.

CONCLUSIONS

Whole blood given to pediatric patients with SMA was associated with improved survival, mainly among those with thrombocytopenia who received whole blood stored for <4 weeks. These findings point to a potential use for incorporating thrombocytopenia into clinical decision making and management of severe malaria, which can be further assessed in prospective studies, and underline the importance of maintaining reliable blood donation networks in areas of high malaria transmission.

Alteration of Blood Lactate Levels in Severe Falciparum Malaria: A Systematic Review and Meta-Analysis

Simple Summary

Alteration of blood lactate levels in patients with severe falciparum malaria is well recognized. However, data on blood lactate in literatures were based on a limited number of participants. The present systematic review aimed to collate the blood lactate levels recorded in the literature and used a metaanalysis approach to pool the evidence in a larger sample size than that used in the individual studies to determine the trend. Results from this study will provide the pooled evidence of blood lactate levels in patients with severe malaria for further studies that identifying patients with a high risk of developing severe malaria or death.

Abstract

Metabolic acidosis in severe malaria usually occurs in the form of lactic acidosis. The present study aimed to collate articles from the literature that have reported blood lactate levels in patients with severe malaria and tested the hypothesis that blood lactate levels are elevated in patients with malaria compared to those with uncomplicated malaria. Moreover, the difference in lactate levels between patients who died and those who survived was estimated using a meta-analytic approach. Potentially relevant studies were searched for in PubMed, Web of Science, and Scopus. The quality of the included studies was assessed using the Jadad scale and strengthening the reporting of observational studies in epidemiology (STROBE). The pooled mean blood lactate in patients with severe malaria, the pooled weighted mean difference (WMD) of blood lactate between patients with severe malaria and those with uncomplicated malaria, and the pooled WMD and 95% CI of blood lactate between patients who died from and those who survived severe malaria were estimated using the random-effects model. Heterogeneity among the outcomes of the included studies was assessed using Cochran’s Q and I² statistics. A meta-regression analysis was performed to identify the source(s) of heterogeneity of outcomes among the included studies. A subgroup analysis was further performed to separately analyze the outcomes stratified by the probable source(s) of heterogeneity. Publication bias was assessed by the visual inspection of the funnel plot asymmetry. Of 793 studies retrieved from the searches, 30 studies were included in qualitative and quantitative syntheses. The pooled mean lactate in patients with severe malaria was 5.04 mM (95% CI: 4.44–5.64; I²: 99.9%; n = 30,202 cases from 30 studies). The mean lactate in patients with severe malaria (1568 cases) was higher than in those with uncomplicated malaria (1693 cases) (p = 0.003; MD: 2.46; 95% CI: 0.85–4.07; I²: 100%; nine studies). The mean lactate in patients with severe malaria who died (272 cases) was higher than in those with severe malaria who survived (1370 cases) (p < 0.001; MD: 2.74; 95% CI: 1.74–3.75; I²: 95.8%; six studies). In conclusion, the present study showed a high mean difference in blood lactate level between patients with severe malaria and patients with uncomplicated malaria. In addition, there was a high mean difference in blood lactate level between patients with severe malaria who died compared to those with severe malaria who survived. Further studies are needed to investigate the prognostic value of blood lactate levels to identify patients who are at high risk of developing severe malaria or dying.

The clinical spectrum of severe childhood malaria in Eastern Uganda

BACKGROUND

Few recent descriptions of severe childhood malaria have been published from high-transmission regions. In the current study, the clinical epidemiology of severe malaria in Mbale, Eastern Uganda, is described, where the entomological inoculation rate exceeds 100 infective bites per year.

METHODS

A prospective descriptive study was conducted to determine the prevalence, clinical spectrum and outcome of severe Plasmodium falciparum malaria at Mbale Regional Referral Hospital in Eastern Uganda. All children aged 2 months-12 years who presented on Mondays to Fridays between 8.00 am and 5.00 pm from 5th May 2011 until 30th April 2012 were screened for parasitaemia. Clinical and laboratory data were then collected from all P. falciparum positive children with features of WHO-defined severe malaria by use of a standardized proforma.

RESULTS

A total of 10 208 children were screened of which 6582 (64%) had a positive blood film. Of these children, 662 (10%) had clinical features of severe malaria and were consented for the current study. Respiratory distress was the most common severity feature (554; 83.7%), while 365/585 (62.4%) had hyperparasitaemia, 177/662 (26.7%) had clinical jaundice, 169 (25.5%) had severe anaemia, 134/660 (20.2%) had hyperlactataemia (lactate ≥ 5 mmol/L), 93 (14.0%) had passed dark red or black urine, 52 (7.9%) had impaired consciousness and 49/662 (7.4%) had hypoxaemia (oxygen saturations < 90%). In-hospital mortality was 63/662 (9.5%) overall but was higher in children with either cerebral malaria (33.3%) or severe anaemia (19.5%). Factors that were independently associated with mortality on multivariate analysis included severe anaemia [odds ratio (OR) 5.36; 2.16-1.32; P = 0.0002], hyperlactataemia (OR 3.66; 1.72-7.80; P = 0.001), hypoxaemia (OR) 3.64 (95% CI 1.39-9.52; P = 0.008), and hepatomegaly (OR 2.29; 1.29-4.06; P = 0.004). No independent association was found between mortality and either coma or hyperparasitaemia.

CONCLUSIONS

Severe childhood malaria remains common in Eastern Uganda where it continues to be associated with high mortality. An unusually high proportion of children with severe malaria had jaundice or gave a history of having recently passed dark red or black urine, an issue worthy of further investigation.

The Human Spleen in Malaria: Filter or Shelter?

The human spleen is an immune sentinel and controls red blood cell (RBC) quality. By mechanically retaining subsets of infected RBCs, the spleen may reduce the pace at which the parasite biomass increases before the adaptive immune response operates. Conversely, the spleen may contribute to malaria pathogenesis, particularly anemia that is associated with splenomegaly. Large spleens may also shelter parasites in chronic carriers. Upon treatment with artemisinins, the spleen clears circulating parasites by pitting and releases 'once-infected' RBCs in circulation. This triggers postartesunate delayed hemolysis and explains the long post-treatment positivity of histidine-rich protein 2 (HRP2)-based dipsticks. Importantly, splenic retention of RBCs also applies to gametocytes, the clearance of which may be enhanced by stiffening them with drugs, a potential way to block malaria transmission.

Modelling pathogen load dynamics to elucidate mechanistic determinants of host-Plasmodium falciparum interactions

During infection, increasing pathogen load stimulates both protective and harmful aspects of the host response. The dynamics of this interaction are hard to quantify in humans, but doing so could improve understanding of mechanisms of disease and protection. We sought to model the contributions of parasite multiplication rate and host response to observed parasite load in individual subjects with Plasmodium falciparum malaria, using only data obtained at the time of clinical presentation, and then to identify their mechanistic correlates. We predicted higher parasite multiplication rates and lower host responsiveness in severe malaria cases, with severe anemia being more insidious than cerebral malaria. We predicted that parasite growth-inhibition was associated with platelet consumption, lower expression of CXCL10 and type-1 interferon-associated genes, but increased cathepsin G and matrix metallopeptidase 9 expression. We found that cathepsin G and matrix metallopeptidase 9 directly inhibit parasite invasion into erythrocytes. Parasite multiplication rate was associated with host iron availability and higher complement factor H levels, lower expression of gametocyte-associated genes but higher expression of translation-associated genes in the parasite. Our findings demonstrate the potential of using explicit modelling of pathogen load dynamics to deepen understanding of host-pathogen interactions and identify mechanistic correlates of protection.

Effect of Plasmodium falciparum infection on blood parameters and their association with clinical severity in adults of Odisha, India

The extent of abnormalities in blood indices and their subsequent effects on clinical severity in malaria differ among populations of different endemicity. However, these alterations have not been well investigated in Odisha, India and their prognostic implications in the context of multi-organ dysfunction (MODS) in severe malaria (SM) are not identified so far. The present study was carried out in 200 adult patients each from uncomplicated malaria and severe malaria groups to examine whether host haematological and biochemical parameters in Plasmodium falciparum infection can act as diagnostic marker for SM in adults patients of Odisha. The results showed thrombocytopenia as a potential risk factor for SM irrespective of disease features with least median platelet counts observed in patients with MODS (Platelet count: 144.5, P = < 0.0001) compared to mild malaria. Logistic regression analysis identified anemia (<10 mg/dl) as independent predictor of MODS (OR = 12.78, 95% CI = 4.93-33.2). The prognostic utility of thrombocytopenia (platelet count: ≤100,000/μl) as marker of MODS was largely modulated by hemoglobin and blood glucose level. Co-existence of hypoglycemia and thrombocytopenia was also observed. Our study revealed changes in blood indices such as low platelet, hemoglobin and blood glucose during falciparum infection in adults can be used as diagnostic criteria for predicting SM in combinations. The study also provides important clue for plausible hypoglycemia mediated platelet necrosis and clearance. Further studies in different endemic regions need to be conducted for validation of these findings and their implication as criteria for diagnosing SM in adults.

Mitochondrial gene sequence variants in children with severe malaria anaemia with or without lactic acidosis: a case control study

BACKGROUND

Evolutionary pressure by Plasmodium falciparum malaria is known to have favoured a large number of human gene adaptations, but there is surprisingly little investigation of the effect of malaria on human mitochondrial sequence variation. Plasmodium falciparum infection can cause severe malaria anaemia (SMA) with insufficient tissue oxygenation, lactic acidosis and death. Despite equal degrees of severe anaemia, some individuals develop lactic acidosis while others do not. A case-control study design was used to investigate whether differences in host mitochondrial gene sequences were associated with lactic acidosis in SMA. Full mitochondrial sequences were obtained from 36 subjects with SMA complicated by lactic acidosis and 37 subjects with SMA without lactic acidosis. The two groups were matched for age, sex, and degree of anaemia.

RESULTS

Compared with the reference sequence, a median of 60 nucleotide variants per individual (interquartile range 4-91) was found, with an average frequency of 3.97 variants per 1000 nucleotides. The frequency and distribution of non-synonymous DNA variants in genes associated with oxidative phosphorylation were not statistically different between the two groups. Non-synonymous variants predicted to have the most disruptive effect on proteins responsible for oxidative phosphorylation were present at a similar frequency in both groups.

CONCLUSIONS

Lactic acidosis in SMA does not appear to be consistently associated with the high prevalence of any mitochondrial gene variant.

NCR3 polymorphism, haematological parameters, and severe malaria in Senegalese patients

Background

Host factors, including host genetic variation, have been shown to influence the outcome of Plasmodium falciparum infection. Genome-wide linkage studies have mapped mild malaria resistance genes on chromosome 6p21, whereas NCR3-412 polymorphism (rs2736191) lying within this region was found to be associated with mild malaria.

Methods

Blood samples were taken from 188 Plasmodium falciparum malaria patients (76 mild malaria patients, 85 cerebral malaria patients, and 27 severe non-cerebral malaria patients). NCR3-412 (rs2736191) was analysed by sequencing, and haematological parameters were measured. Finally, their association with clinical phenotypes was assessed.

Results

We evidenced an association of thrombocytopenia with both cerebral malaria and severe non-cerebral malaria, and of an association of high leukocyte count with cerebral malaria. Additionally, we found no association of NCR3-412 with either cerebral malaria, severe non-cerebral malaria, or severe malaria after grouping cerebral malaria and severe non-cerebral malaria patients.

Conclusions

Our results suggest that NCR3 genetic variation has no effect, or only a small effect on the occurrence of severe malaria, although it has been strongly associated with mild malaria. We discuss the biological meaning of these results. Besides, we confirmed the association of thrombocytopenia and high leukocyte count with severe malaria phenotypes.

Anemia was an Uncommon Complication of Severe Malaria in a High-Transmission Rural Area of Western Uganda

The clinical epidemiology of severe malaria among patients presenting to peripheral health centers has not been well described. We conducted a prospective, observational cohort study to describe the epidemiology and clinical manifestations of severe malaria in a highland area of declining transmission intensity in Western Uganda. Individuals presenting with a history of fever were screened with a malaria rapid diagnostic test (RDT). We prepared blood smears and conducted clinical and laboratory testing for those with a positive RDT. We defined severe malaria in accordance with World Health Organization guidelines for research and epidemiological studies. A total of 6,641 individuals underwent testing for malaria. Ninety-six of 1,462 (6.6%) participants with confirmed parasitemia satisfied the criteria for severe malaria. The incidence of severe malaria peaked between 2 and 3 years of age (incidence rate ratio = 17.1, 95% confidence interval = 8.4-34.9, P < 0.001) and then declined steadily until age 10. However, we also found a second peak among those ≥ 50 years of age. Severe anemia was uncommon, detected in only 5.3% of cases. Instead, shock (22.2%) and lactic acidosis (19.4%) were most frequently encountered. Our results suggest that the clinical characteristics of severe malaria presenting to rural, peripheral health centers may be different than previously observed in referral centers. These findings merit further investigation into the optimal methods for identification and management of severe malaria in rural health centers in the region.

Use of a Dual-Antigen Rapid Diagnostic Test to Screen Children for Severe Plasmodium falciparum Malaria in a High-Transmission, Resource-Limited Setting

BACKGROUND

In rural areas, many patients with malaria seek care at peripheral health facilities or community case management programs. While this strategy is effective for the management of uncomplicated malaria, severe malaria necessitates prompt detection and referral to facilities with adequate resources.

METHODS

In this prospective, observational cohort study, we assessed the accuracy of a dual-band (histidine-rich protein-2/pan-lactate dehydrogenase [HRP2/pLDH]) rapid diagnostic test (RDT) to differentiate uncomplicated from severe malaria. We included children aged <12 years who presented to a rural clinic in western Uganda with a positive HRP2 or HRP2/pLDH RDT. We estimated the test characteristics of a dual-antigen (HRP2+/pLDH+) band positive RDT compared to World Health Organization-defined clinical and laboratory criteria to detect severe malaria.

RESULTS

A total of 2678 children underwent testing for malaria with an RDT, and 83 (9.0%) satisfied criteria for severe malaria. The sensitivity and specificity of a HRP2+/pLDH+ result for severe malaria was 97.6% (95% confidence interval [CI], 90.8%-99.6%) and 75.6% (95% CI, 73.8%-77.4%), respectively. An HRP2+/pLDH+ result was significantly more sensitive (97.6% vs 68.7%, P < .001) for the detection of severe malaria compared to algorithms that incorporate screening for danger signs.

CONCLUSIONS

A positive dual-antigen (HRP2/pLDH) RDT has higher sensitivity than the use of clinical manifestations to detect severe malaria, making it a promising tool in the triage of children with malaria in low-resource settings. Additional work is needed to operationalize diagnostic and treatment algorithms that include dual-antigen RDTs to avoid over referral.

Severe imported malaria in children in France. A national retrospective study from 1996 to 2005

BACKGROUNDS

Malaria is a leading cause of imported febrile illnesses in pediatric travelers, but few studies have addressed severe imported pediatric malaria. We aimed to determine the risk factors and the features of imported pediatric severe malaria.

METHODS

We conducted a retrospective, descriptive study using the French National Reference Center for Imported Malaria database, in children aged 0-15 years who were hospitalized with a falciparum malaria from January 1st 1996 to December 31th 2005. Uncomplicated and severe cases of falciparum malaria were compared to identify risk factors for severe cases. In the hospitals that reported more than five severe cases during the study period, we evaluated severe cases for prognostic factors and assessed the accuracy WHO criteria for predicting severity. Given the rarity of deaths, adverse outcomes were defined as requiring major therapeutic procedures (MTPs)-e.g., sedation, mechanical ventilation, nasal oxygen therapy, blood transfusions, hemodialysis, fluid resuscitation-or pediatric intensive care unit (PICU) admission.

RESULTS

Of 4150 pediatric malaria cases included in the study, 3299 were uncomplicated and 851 (20.5%) were severe. Only one death was recorded during this period. Predictors for severe falciparum malaria were: age <2 years (OR = 3.2, 95% CI = 2.5-4.0, p <0.0001) and a travel in the Sahelian region (OR = 1.7, 95% CI = 1.3-2.0, p = 0.0001). Of 422 severe malaria cases, a stay in a Sahelian region, lack of chemoprophylaxis, age <2 years or thrombocytopenia <100 x 10^3/mm^3 predicted adverse outcomes. Except for the hyperparasitemia threshold of 4%, the main WHO 2000 criteria for severe malaria reliably predicted adverse outcomes. In our study, the threshold of parasitemia most predictive of a poor outcome was 8%.

CONCLUSION

In imported pediatric malaria, children younger than 2 years deserve particular attention. The main WHO 2000 criteria for severity are accurate, except for the threshold of hyperparasitemia, which should be revised.

Young Sprague Dawley rats infected by Plasmodium berghei: A relevant experimental model to study cerebral malaria

Cerebral malaria (CM) is the most severe manifestation of human malaria yet is still poorly understood. Mouse models have been developed to address the subject. However, their relevance to mimic human pathogenesis is largely debated. Here we study an alternative cerebral malaria model with an experimental Plasmodium berghei Keyberg 173 (K173) infection in Sprague Dawley rats. As in Human, not all infected subjects showed cerebral malaria, with 45% of the rats exhibiting Experimental Cerebral Malaria (ECM) symptoms while the majority (55%) of the remaining rats developed severe anemia and hyperparasitemia (NoECM). These results allow, within the same population, a comparison of the noxious effects of the infection between ECM and severe malaria without ECM. Among the ECM rats, 77.8% died between day 5 and day 12 post-infection, while the remaining rats were spontaneously cured of neurological signs within 24-48 hours. The clinical ECM signs observed were paresis quickly evolving to limb paralysis, global paralysis associated with respiratory distress, and coma. The red blood cell (RBC) count remained normal but a drastic decrease of platelet count and an increase of white blood cell numbers were noted. ECM rats also showed a decrease of glucose and total CO2 levels and an increase of creatinine levels compared to control rats or rats with no ECM. Assessment of the blood-brain barrier revealed loss of integrity, and interestingly histopathological analysis highlighted cyto-adherence and sequestration of infected RBCs in brain vessels from ECM rats only. Overall, this ECM rat model showed numerous clinical and histopathological features similar to Human CM and appears to be a promising model to achieve further understanding the CM pathophysiology in Humans and to evaluate the activity of specific antimalarial drugs in avoiding/limiting cerebral damages from malaria.

Epidemiological and clinical profile of paediatric malaria: a cross sectional study performed on febrile children in five epidemiological strata of malaria in Cameroon

Background

In the wake of a decline in global malaria, it is imperative to describe the epidemiology of malaria in a country to inform control policies. The purpose of this study was to describe the epidemiological and clinical profile of paediatric malaria in five epidemiological strata of malaria in Cameroon including: the Sudano-sahelian (SS) strata, the High inland plateau (HIP) strata, the South Cameroonian Equatorial forest (SCEF) strata, the High western plateau (HWP) strata, and the Coastal (C) strata.

Methods

This study involved 1609 febrile children (≤15 years) recruited using reference hospitals in the five epidemiological strata. Baseline characteristics were determined; blood glucose level was measured by a glucometer, malaria parasitaemia was assessed by Giemsa microscopy, and complete blood count was performed using an automated hematology analyser. Severe malaria was assessed and categorized based on WHO criteria.

Results

An overall prevalence of 15.0% (95% CI: 13.3–16.9) for malaria was observed in this study. Malaria prevalence was significantly higher in children between 60 and 119 months (p < 0.001) and in Limbe (C strata) (p < 0.001). The overall rate of severe malaria (SM) attack in this study was 29.3%; SM was significantly higher in children below 60 months (p < 0.046). Although not significant, the rate of SM was highest in Maroua (SS strata) and lowest in Limbe in the C strata. The main clinical phenotypes of SM were hyperparasitaemia, severe malaria anaemia and impaired consciousness. The majority (73.2%) of SM cases were in group 1 of the WHO classification of severe malaria (i.e. the most severe form). The malaria case-fatality rate was 5.8%; this was higher in Ngaoundere (HIP strata) (p = 0.034).

Conclusion

In this study, malaria prevalence decreased steadily northward, from the C strata in the South to the SS strata in the North of Cameroon, meanwhile the mortality rate associated with malaria increased in the same direction. On the contrary, the rate of severe malaria attack was similar across the different epidemiological strata. Immunoepidemiological studies will be required to shed more light on the observed trends.

Hematological Parameters and Hemozoin-Containing Leukocytes and Their Association with Disease Severity among Malaria Infected Children: A Cross-Sectional Study at Pawe General Hospital, Northwest Ethiopia

Hematological parameter changes are the most common complications in malaria. We aimed to determine the hematological parameters and hemozoin-containing leukocytes and their association with disease severity in malaria infected children aged between 1 and 15 years. A facility-based cross-sectional study was conducted at Pawe General Hospital from July 31 to December 30, 2014. Demographic and clinical data were collected using structured questionnaire. Blood specimen was collected from each study participant for hematological investigations. Data were analyzed using SPSS version 20. The overall prevalence of anemia was 40.3%, most of which were mildly anemic. Leukocytosis was found in 15.4% of study participants. More than a fourth (27%) of the children had severe malaria. Hemozoin-containing monocytes and neutrophils were found in 80.1% and 58.9% of the study participants, respectively. Under-five years of age (AOR = 3.01, 95% CI: 1.83–7.39, P < 0.001), leukocytosis (AOR = 3.20, 95% CI: 1.65–6.24, P = 0.001), mean hemozoin-containing monocytes >5% (AOR = 6.26, 95% CI: 2.14–14.29, P < 0.001), mean hemozoin-containing neutrophils >5% (AOR = 7.93, 95% CI: 3.09–16.86, P < 0.001), and high density parasitemia (AOR = 1.90, 95% CI: 1.13–3.18, P = 0.015) were associated with severe malaria. Hemozoin-containing leukocytes, leukocytosis, and other identified associated factors should be considered for proper management of children with severe malaria.

Retrospective study of imported falciparum malaria in French paediatric intensive care units

OBJECTIVE

The World Health Organization (WHO) severity criteria for paediatric Plasmodium falciparum (Pf) malaria are based on studies in countries of endemic malaria. The relevance of these criteria for other countries remains unclear. We assessed the relevance of these criteria in an industrialised country.

DESIGN

Retrospective case-control study.

SETTING

Eight French university hospitals, from 2006 to 2012.

PATIENTS

Children with Pf malaria admitted to paediatric intensive care units (cases: n=55) or paediatric emergency departments (controls: n=110).

MAIN OUTCOME MEASURES

Descriptive analysis of WHO severity criteria and major interventions (mechanical ventilation, blood transfusion, fluid challenge, treatment of cerebral oedema, renal replacement therapy). Thresholds were set by receiver operating characteristics curve analysis.

RESULTS

Altered consciousness (71% vs 5%), shock (24% vs 1%), renal failure (20% vs 1%), anaemia <50 g/L (7% vs 2%), acidosis (38% vs 0%), bilirubin level >50 µmol/L (25% vs 8%) and parasitaemia >10% (30% vs 8%) were more frequent in cases (p<0.01). All these criteria were associated with major interventions (p<0.001). Respiratory distress (six cases), and hypoglycaemia (two cases) were infrequent. Thrombocytopenia <50 000/mm³ (46% vs 7%) and anaemia (haemoglobin concentration <70 g/L (41% vs 13%)) were more frequent in cases (p<0.0001).

CONCLUSIONS

The WHO severity criteria for paediatric Pf malaria are relevant for countries without endemic malaria. The infrequent but severe complications also provide a timely reminder of the morbidity and mortality associated with this condition worldwide. In non-endemic countries haemoglobin <70 g/L and platelet count <50 000/mm³ could be used as additional criteria to identify children needing high level of care.

Differing Causes of Lactic Acidosis and Deep Breathing in Cerebral Malaria and Severe Malarial Anemia May Explain Differences in Acidosis-Related Mortality

Lactic acidosis (LA) is a marker for mortality in severe malaria, but the mechanisms that lead to LA in the different types of severe malaria and the extent to which LA-associated mortality differs by type of severe malaria are not well described. We assessed the frequency of LA in children admitted to Mulago Hospital, Kampala, Uganda with cerebral malaria (CM, n = 193) or severe malarial anemia (SMA, n = 216). LA was compared to mortality and measures of parasite biomass and sequestration (P. falciparum histidine-rich protein-2 (PfHRP2) concentration, platelet count), and to a measure of systemic tissue oxygen delivery (hemoglobin level). LA was more frequent in children with SMA than CM (SMA, 47.7%, CM, 34.2%, P = 0.006), but mortality was higher in children with CM (13.0%) than SMA (0.5%, P<0.0001). In CM, LA was associated with increased PfHRP2 concentration and decreased platelet count but was not associated with hemoglobin level. In contrast, in SMA, LA was associated with a decreased hemoglobin level, but was not associated with PfHRP2 concentration or platelet count. LA was related to mortality only in CM. In multivariable regression analysis of the effect PfHRP2 and hemoglobin levels on LA and DB, only PfHRP2 level increased risk of LA and DB in CM, while in SMA, elevated hemoglobin strongly decreased risk of LA and DB, and PfHRP2 level modestly increased risk of LA. The study findings suggest that LA in CM is due primarily to parasite sequestration, which currently has no effective adjunctive therapy, while LA in SMA is due primarily to anemia, which is rapidly corrected with blood transfusion. Differing etiologies of LA in CM and SMA may explain why LA is associated with mortality in CM but not SMA.

Transfusion Medicine in Sub-Saharan Africa: Conference Summary

In November 2014, a 3-day conference devoted to transfusion medicine in sub-Saharan Africa was held in Kampala, Uganda. Faculty from academic institutions in Uganda provided a broad overview of issues pertinent to transfusion medicine in Africa. The conference consisted of lectures, demonstrations, and discussions followed by 5 small group workshops held at the Uganda Blood Transfusion Service Laboratories, the Ugandan Cancer Institute, and the Mulago National Referral Hospital. Highlighted topics included the challenges posed by increasing clinical demands for blood, the need for better patient identification at the time of transfusion, inadequate application of the antiglobulin reagent during pretransfusion testing, concern regarding proper recognition and evaluation of transfusion reactions, the expanded role for nurse leadership as a means to improve patient outcomes, and the need for an epidemiologic map of blood usage in Africa. Specialty areas of focus included the potential for broader application of transcranial Doppler and hydroxyurea therapy in sickle cell disease, African-specific guidelines for transfusion support of cancer patients, the challenges of transfusion support in trauma, and the importance of African-centered clinical research in pediatric and obstetric transfusion medicine. The course concluded by summarizing the benefits derived from an organized quality program that extended from the donor to the recipient. As an educational tool, the slide-audio presentation of the lectures will be made freely available at the International Society of Blood Transfusion Academy Web site: http://www.isbtweb.org/academy/.

Innocent lives lost and saved: the importance of blood transfusion for children in sub-Saharan Africa

Severe anemia in children is a leading indication for blood transfusion worldwide. Severe anemia, defined by the World Health Organization as a hemoglobin level <5 g/dL, is particularly common throughout sub-Saharan Africa. Analysis of data from the Fluid Expansion as Supportive Therapy (FEAST) trial offers new insights into the importance of blood transfusion for children with severe anemia. The principal findings of this analysis include the observations that life-threatening anemia in children is a frequent presenting condition in East Africa; that delays in transfusion therapy are lethal; and that inadequate transfusion is probably more common than currently recognized. The findings of this new study highlight the need for changes in blood inventory management in sub-Saharan hospitals and the need for more research on transfusion therapy for children in peril.

Anaemia and blood transfusion in African children presenting to hospital with severe febrile illness

BACKGROUND

Severe anaemia in children is a leading cause of hospital admission and a major cause of mortality in sub-Saharan Africa, yet there are limited published data on blood transfusion in this vulnerable group.

METHODS

We present data from a large controlled trial of fluid resuscitation (Fluid Expansion As Supportive Therapy (FEAST) trial) on the prevalence, clinical features, and transfusion management of anaemia in children presenting to hospitals in three East African countries with serious febrile illness (predominantly malaria and/or sepsis) and impaired peripheral perfusion.

RESULTS

Of 3,170 children in the FEAST trial, 3,082 (97%) had baseline haemoglobin (Hb) measurement, 2,346/3,082 (76%) were anaemic (Hb <10 g/dL), and 33% severely anaemic (Hb <5 g/dL). Prevalence of severe anaemia varied from 12% in Kenya to 41% in eastern Uganda. 1,387/3,082 (45%) children were transfused (81% within 8 hours). Adherence to WHO transfusion guidelines was poor. Among severely anaemic children who were not transfused, 52% (54/103) died within 8 hours, and 90% of these deaths occurred within 2.5 hours of randomisation. By 24 hours, 128/1,002 (13%) severely anaemic children had died, compared to 36/501 (7%) and 71/843 (8%) of those with moderate and mild anaemia, respectively. Among children without severe hypotension who were randomised to receive fluid boluses of 0.9% saline or albumin, mortality was increased (10.6% and 10.5%, respectively) compared to controls (7.2%), regardless of admission Hb level. Repeat transfusion varied from ≤2% in Kenya/Tanzania to 6 to 13% at the four Ugandan centres. Adverse reactions to blood were rare (0.4%).

CONCLUSIONS

Severe anaemia complicates one third of childhood admissions with serious febrile illness to hospitals in East Africa, and is associated with increased mortality. A high proportion of deaths occurred within 2.5 hours of admission, emphasizing the need for rapid recognition and prompt blood transfusion. Adherence to current WHO transfusion guidelines was poor. The high rates of re-transfusion suggest that 20 mL/kg whole blood or 10 mL/kg packed cells may undertreat a significant proportion of anaemic children. Future evaluation of the impact of a larger volume of transfused blood and optimum transfusion management of children with Hb of <6 g/dL is warranted.

Severe malarial anemia is associated with long-term neurocognitive impairment

BACKGROUND

Cerebral malaria (CM) is associated with long-term neurocognitive impairment in children ≥5 years of age. No prospective studies to date have assessed neurocognitive impairment in children with CM <5 years of age, or in children with severe malarial anemia (SMA), a form of severe malaria estimated to affect as many as 5 million children annually.

METHODS

Children <5 years of age presenting to Mulago Hospital, Kampala, Uganda, with CM (n = 80) or SMA (n = 86) were assessed for overall cognitive ability, attention, and associative memory 1 week after discharge and 6 and 12 months later. The z scores for each domain were computed based on scores of 61 healthy community children (CC), who were also tested at enrollment and 6 and 12 months later. Groups were compared using mixed linear models, adjusted for age, weight for age, and child's education.

RESULTS

At 12 months, children with CM had lower adjusted scores than CC in cognitive ability (P < .001), attention (P = .02), and associative memory, (P = .002). Children with SMA had lower scores than CC in cognitive ability (P = .01) but not attention or associative memory. Cognitive ability scores in children with CM and SMA did not differ significantly.

CONCLUSIONS

In children <5 years of age, SMA is associated with long-term impairment in cognitive ability, whereas CM is associated with additional impairment in the areas of attention and associative memory. SMA may be a major contributor to long-term neurocognitive impairment in children in sub-Saharan Africa.

Hemozoin-generated vapor nanobubbles for transdermal reagent- and needle-free detection of malaria

Successful diagnosis, screening, and elimination of malaria critically depend on rapid and sensitive detection of this dangerous infection, preferably transdermally and without sophisticated reagents or blood drawing. Such diagnostic methods are not currently available. Here we show that the high optical absorbance and nanosize of endogenous heme nanoparticles called "hemozoin," a unique component of all blood-stage malaria parasites, generates a transient vapor nanobubble around hemozoin in response to a short and safe near-infrared picosecond laser pulse. The acoustic signals of these malaria-specific nanobubbles provided transdermal noninvasive and rapid detection of a malaria infection as low as 0.00034% in animals without using any reagents or drawing blood. These on-demand transient events have no analogs among current malaria markers and probes, can detect and screen malaria in seconds, and can be realized as a compact, easy-to-use, inexpensive, and safe field technology.

The blood supply in Sub-Saharan Africa: needs, challenges, and solutions

Sub-Saharan Africa (SSA) is burdened with a growing population and poor health care resources. Transfusion medicine is uniquely affected for SSA as a result of a combination of factors which put tremendous pressure on the blood supply. In this review, we consider these factors including: malaria, sickle cell anemia, transfusion medicine infrastructure, and past transfusion medicine policies including those which are tied to foreign aid, such as a VNRD-only practice. We also consider how SSA can overcome some of these hurdles to achieve a safe and adequate blood supply for its people through the advent of new vaccines, medications, infrastructure development, policy changes, and education.

The effect of blood storage age on treatment of lactic acidosis by transfusion in children with severe malarial anaemia: a pilot, randomized, controlled trial

Background

Severe malarial anaemia requiring blood transfusion is a life-threatening condition affecting millions of children in sub-Saharan Africa. Up to 40% of children with severe malarial anaemia have associated lactic acidosis. Lactic acidosis in these children is strongly associated with fatal outcomes and is corrected by blood transfusion. However, it is not known whether the storage age of blood for transfusion affects resolution of lactic acidosis. The objective of this pilot study was to evaluate the effect of blood storage age on resolution of lactic acidosis in children with severe malarial anaemia and demonstrate feasibility of conducting a large trial.

Methods

Children aged six to 59 months admitted to Acute Care Unit of Mulago Hospital (Kampala, Uganda) with severe malarial anaemia (haemoglobin ≤ 5 g/dL) and lactic acidosis (blood lactate ≥5 mmol/L), were randomly assigned to receive either blood of short storage age (one to 10 days) or long storage age (21–35 days) by gravity infusion. Seventy-four patients were enrolled and randomized to two equal-sized study arms. Physiological measurements, including blood lactate, oxygen saturation, haemoglobin, and vital signs, were taken at baseline, during and after transfusion. The primary outcome variable was the proportion of children whose lactic acidosis resolved by four hours after transfusion.

Results

Thirty-four of 37 (92%) of the children in the short storage treatment arm compared to 30/37 (81%) in the long storage arm achieved a blood lactate <5 mmol/L by four hours post transfusion (p value = 0.308). The mean time to lactic acidosis resolution was 2.65 hours (95% CI; 2.25–3.05) in the short storage arm, compared to 3.35 hours (95% CI; 2.60–4.10) in the long storage arm (p value = 0.264).

Conclusion

Pilot data suggest that among children with severe malarial anaemia and lactic acidosis transfused with packed red blood cells, the storage age of blood does not affect resolution of lactic acidosis. The results support a larger and well-powered study which is under way.

Trial registration

clinicaltrials.gov NCT01580111