A systems serology approach to identifying key antibody correlates of protection from cerebral malaria in Malawian children.

BACKGROUND: Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins are expressed on the surface of infected erythrocytes, mediating parasite sequestration in the vasculature. PfEMP1 is a major target of protective antibodies, but the features of the antibody response are poorly defined. METHODS: In Malawian children with cerebral or uncomplicated malaria, we characterized the antibody response to 39 recombinant PfEMP1 Duffy binding like (DBL) domains or cysteine-rich interdomain regions (CIDRs) in detail, including measures of antibody classes, subclasses, and engagement with Fcγ receptors and complement. Using elastic net regularized logistic regression, we identified a combination of seven antibody targets and Fc features that best distinguished between children with cerebral and uncomplicated malaria. To confirm the role of the selected targets and Fc features, we measured antibody-dependent neutrophil and THP-1 cell phagocytosis of intercellular adhesion molecule-1 (ICAM-1) and endothelial protein C (EPCR) co-binding infected erythrocytes. RESULTS: The selected features distinguished between children with cerebral and uncomplicated malaria with 87% accuracy (median, 80-96% interquartile range) and included antibody to well-characterized DBLß3 domains and a less well-characterized CIDRγ12 domain. The abilities of antibodies to engage C1q and FcγRIIIb, rather than levels of IgG, correlated with protection. In line with a role of FcγRIIIb binding antibodies to DBLß3 domains, antibody-dependent neutrophil phagocytosis of ICAM-1 and EPCR co-binding IE was higher in uncomplicated malaria (15% median, 8-38% interquartile range) compared to cerebral malaria (7%, 30-15%, p < 0.001). CONCLUSIONS: Antibodies associated with protection from cerebral malaria target a subset of PfEMP1 domains. The Fc features of protective antibody response include engagement of FcγRIIIb and C1q, and ability to induce antibody-dependent neutrophil phagocytosis of infected erythrocytes. Identifying the targets and Fc features of protective immunity could facilitate the development of PfEMP1-based therapeutics for cerebral malaria.

Barriers to accessing malaria treatment amongst school-age children in rural Malawi.

BACKGROUND: Over the last two decades, many countries have moved from malaria control toward malaria elimination. However, some sub-Saharan African countries, like Malawi, have recently seen a reversal in malaria control progress with reported increases in confirmed malaria cases. This may be the result of inadequate access to effective malaria control interventions by key population groups that perpetuate transmission. This study aimed to assess the barriers to accessing malaria treatment among school-aged children (SAC) in Malawi. METHODS: A qualitative study was conducted between September and October 2020, where data were gathered in rural Malawi using free-listing interviews, key-informant interviews, semi-structured interviews and focus group discussions. Purposively sampled participants included SAC, parents of SAC, health workers and key stakeholders at community and district levels. Interviews were digitally recorded and transcribed verbatim. Data were organized using NVivo 12 software and analysed using the thematic method. RESULTS: The study recruited 252 participants, with 156 being SAC, equally divided between boys and girls. Health system barriers to malaria treatment included long waiting hours and queues at clinics, frequent stock-outs of medical supplies, and travel time to the facility. Provider barriers included negative attitude and limited service hours. Individual and cultural barriers included fear of malaria tests and beliefs associating witchcraft as the best treatment for malaria. In addition, COVID-19-related barriers included the inability to follow preventive measures, a shift in focus from malaria to COVID-19, and fear of contracting COVID-19 and/or being tested for COVID-19 at the facility. CONCLUSIONS: This study shows most of the barriers to accessing malaria treatment among SAC are similar to those experienced by other population groups. Furthermore, COVID-19 adversely affected SAC's access to treatment. Interventions that support SAC access to prompt diagnosis and treatment are urgently needed to improve the effective control of malaria.

The ability of Interleukin-10 to negate haemozoin-related pro-inflammatory effects has the potential to restore impaired macrophage function associated with malaria infection.

BACKGROUND: Although pro-inflammatory cytokines are involved in the clearance of Plasmodium falciparum during the early stages of the infection, increased levels of these cytokines have been implicated in the pathogenesis of severe malaria. Amongst various parasite-derived inducers of inflammation, the malarial pigment haemozoin (Hz), which accumulates in monocytes, macrophages and other immune cells during infection, has been shown to significantly contribute to dysregulation of the normal inflammatory cascades. METHODS: The direct effect of Hz-loading on cytokine production by monocytes and the indirect effect of Hz on cytokine production by myeloid cells was investigated during acute malaria and convalescence using archived plasma samples from studies investigating P. falciparum malaria pathogenesis in Malawian subjects. Further, the possible inhibitory effect of IL-10 on Hz-loaded cells was examined, and the proportion of cytokine-producing T-cells and monocytes during acute malaria and in convalescence was characterized. RESULTS: Hz contributed towards an increase in the production of inflammatory cytokines, such as Interferon Gamma (IFN-γ), Tumor Necrosis Factor (TNF) and Interleukin 2 (IL-2) by various cells. In contrast, the cytokine IL-10 was observed to have a dose-dependent suppressive effect on the production of TNF among other cytokines. Cerebral malaria (CM) was characterized by impaired monocyte functions, which normalized in convalescence. CM was also characterized by reduced levels of IFN-γ-producing T cell subsets, and reduced expression of immune recognition receptors HLA-DR and CD 86, which also normalized in convalescence. However, CM and other clinical malaria groups were characterized by significantly higher plasma levels of pro-inflammatory cytokines than healthy controls, implicating anti-inflammatory cytokines in balancing the immune response. CONCLUSIONS: Acute CM was characterized by elevated plasma levels of pro-inflammatory cytokines and chemokines but lower proportions of cytokine-producing T-cells and monocytes that normalize during convalescence. IL-10 is also shown to have the potential to indirectly prevent excessive inflammation. Cytokine production dysregulated by the accumulation of Hz appears to impair the balance of the immune response to malaria and exacerbates pathology.

Artemether-lumefantrine efficacy among adults on antiretroviral therapy in Malawi.

BACKGROUND: When people with human immunodeficiency virus (HIV) infection (PWH) develop malaria, they are at risk of poor anti-malarial treatment efficacy resulting from impairment in the immune response and/or drug-drug interactions that alter anti-malarial metabolism. The therapeutic efficacy of artemether-lumefantrine was evaluated in a cohort of PWH on antiretroviral therapy (ART) and included measurement of day 7 lumefantrine levels in a subset to evaluate for associations between lumefantrine exposure and treatment response. METHODS: Adults living with HIV (≥ 18 years), on ART for ≥ 6 months with undetectable HIV RNA viral load and CD4 count ≥ 250/mm3 were randomized to daily trimethoprim-sulfamethoxazole (TS), weekly chloroquine (CQ) or no prophylaxis. After diagnosis of uncomplicated Plasmodium falciparum malaria, a therapeutic efficacy monitoring was conducted with PCR-correction according to WHO guidelines. The plasma lumefantrine levels on day 7 in 100 episodes of uncomplicated malaria was measured. A frailty proportional hazards model with random effects models to account for clustering examined the relationship between participant characteristics and malaria treatment failure within 28 days. Pearson's Chi-squared test was used to compare lumefantrine concentrations among patients with treatment failure and adequate clinical and parasitological response (ACPR). RESULTS: 411 malaria episodes were observed among 186 participants over 5 years. The unadjusted ACPR rate was 81% (95% CI 77-86). However, after PCR correction to exclude new infections, ACPR rate was 94% (95% CI 92-97). Increasing age and living in Ndirande were associated with decreased hazard of treatment failure. In this population of adults with HIV on ART, 54% (51/94) had levels below a previously defined optimal day 7 lumefantrine level of 200 ng/ml. This occurred more commonly among participants who were receiving an efavirenz-based ART compared to other ART regimens (OR 5.09 [95% CI 1.52-7.9]). Participants who experienced treatment failure had lower day 7 median lumefantrine levels (91 ng/ml [95% CI 48-231]) than participants who experienced ACPR (190 ng/ml [95% CI 101-378], p-value < 0.008). CONCLUSION: Recurrent malaria infections are frequent in this population of PWH on ART. The PCR-adjusted efficacy of AL meets the WHO criteria for acceptable treatment efficacy. Nevertheless, lumefantrine levels tend to be low in this population, particularly in those on efavirenz-based regimens, with lower concentrations associated with more frequent malaria infections following treatment. These results highlight the importance of understanding drug-drug interactions when diseases commonly co-occur.

Automated analysis of low-field brain MRI in cerebral malaria.

A central challenge of medical imaging studies is to extract biomarkers that characterize disease pathology or outcomes. Modern automated approaches have found tremendous success in high-resolution, high-quality magnetic resonance images. These methods, however, may not translate to low-resolution images acquired on magnetic resonance imaging (MRI) scanners with lower magnetic field strength. In low-resource settings where low-field scanners are more common and there is a shortage of radiologists to manually interpret MRI scans, it is critical to develop automated methods that can augment or replace manual interpretation, while accommodating reduced image quality. We present a fully automated framework for translating radiological diagnostic criteria into image-based biomarkers, inspired by a project in which children with cerebral malaria (CM) were imaged using low-field 0.35 Tesla MRI. We integrate multiatlas label fusion, which leverages high-resolution images from another sample as prior spatial information, with parametric Gaussian hidden Markov models based on image intensities, to create a robust method for determining ventricular cerebrospinal fluid volume. We also propose normalized image intensity and texture measurements to determine the loss of gray-to-white matter tissue differentiation and sulcal effacement. These integrated biomarkers have excellent classification performance for determining severe brain swelling due to CM.

How Does Blood-Retinal Barrier Breakdown Relate to Death and Disability in Pediatric Cerebral Malaria?

BACKGROUND: In cerebral malaria, the retina can be used to understand disease pathogenesis. The mechanisms linking sequestration, brain swelling, and death remain poorly understood. We hypothesized that retinal vascular leakage would be associated with brain swelling. METHODS: We used retinal angiography to study blood-retinal barrier integrity. We analyzed retinal leakage, histopathology, brain magnatic resonance imaging (MRI), and associations with death and neurological disability in prospective cohorts of Malawian children with cerebral malaria. RESULTS: Three types of retinal leakage were seen: large focal leak (LFL), punctate leak (PL), and vessel leak. The LFL and PL were associated with death (odds ratio [OR] = 13.20, 95% confidence interval [CI] = 5.21-33.78 and OR = 8.58, 95% CI = 2.56-29.08, respectively) and brain swelling (P < .05). Vessel leak and macular nonperfusion were associated with neurological disability (OR = 3.71, 95% CI = 1.26-11.02 and OR = 9.06, 95% CI = 1.79-45.90). Large focal leak was observed as an evolving retinal hemorrhage. A core of fibrinogen and monocytes was found in 39 (93%) white-centered hemorrhages. CONCLUSIONS: Blood-retina barrier breakdown occurs in 3 patterns in cerebral malaria. Associations between LFL, brain swelling, and death suggest that the rapid accumulation of cerebral hemorrhages, with accompanying fluid egress, may cause fatal brain swelling. Vessel leak, from barrier dysfunction, and nonperfusion were not associated with severe brain swelling but with neurological deficits, suggesting hypoxic injury in survivors.

School-Based Malaria Screening and Treatment Reduces Plasmodium falciparum Infection and Anemia Prevalence in Two Transmission Settings in Malawi.

BACKGROUND: In areas highly endemic for malaria, Plasmodium falciparum infection prevalence peaks in school-age children, adversely affecting health and education. School-based intermittent preventive treatment reduces this burden but concerns about cost and widespread use of antimalarial drugs limit enthusiasm for this approach. School-based screening and treatment is an attractive alternative. In a prospective cohort study, we evaluated the impact of school-based screening and treatment on the prevalence of P. falciparum infection and anemia in 2 transmission settings. METHODS: We screened 704 students in 4 Malawian primary schools for P. falciparum infection using rapid diagnostic tests (RDTs), and treated students who tested positive with artemether-lumefantrine. We determined P. falciparum infection by microscopy and quantitative polymerase chain reaction (qPCR), and hemoglobin concentrations over 6 weeks in all students. RESULTS: Prevalence of infection by RDT screening was 37% (9%-64% among schools). An additional 9% of students had infections detected by qPCR. Following the intervention, significant reductions in infections were detected by microscopy (adjusted relative reduction [aRR], 48.8%; P < .0001) and qPCR (aRR, 24.5%; P < .0001), and in anemia prevalence (aRR, 30.8%; P = .003). Intervention impact was reduced by infections not detected by RDT and new infections following treatment. CONCLUSIONS: School-based screening and treatment reduced P. falciparum infection and anemia. This approach could be enhanced by repeating screening, using more-sensitive screening tests, and providing longer-acting drugs. CLINICAL TRIALS REGISTRATION: NCT04858087.

"I do lack peace, and I've run out of answers": primary caregivers' perspectives on social and behaviour problems in cerebral malaria survivors in Blantyre, Malawi.

BACKGROUND: Despite recent advances in treatment and prevention, the prevalence of cerebral malaria (CM) remains high globally, especially in children under 5 years old. As treatment improves, more children will survive episodes of CM with lasting neurodisabilities, such as social and behavioural issues. Behaviour problems in children who survive CM are poorly characterized, and the impact of caring for a child with post-CM behaviour issues has not been well-explored. Caregivers' perceptions of and experiences with their child's post-CM behaviour problems are reported here. METHODS: Semi-structured interviews were conducted with 29 primary caregivers of children who survived CM with reported behaviour issues in Blantyre, Malawi. Interviews were conducted in Chichewa, audio-recorded, transcribed, and translated into English. Data were coded manually, utilizing inductive and deductive approaches. Identified codes were thematically analysed. RESULTS: Post-CM behaviours reported include externalizing, aggressive behaviours and learning difficulties. Variable timescales for behaviour change onset were noted, and most caregivers reported some evolution of their child's behaviour over time. Caregivers experienced a variety of emotions connected to their child's behaviour and to reactions of family and community members. Caregivers who experienced discrimination were more likely to describe negative emotions tied to their child's behaviour changes, compared to caregivers who experienced support. CONCLUSIONS: Caregiver perceptions of behaviour changes in post-CM survivors are variable, and caregiver experience is strongly impacted by family and community member responses. Future educational, rehabilitation, and support-based programmes should focus on the specific types of behaviour problems identified and the difficulties faced by caregivers and their communities.

Mechanisms of Transcranial Doppler Ultrasound phenotypes in paediatric cerebral malaria remain elusive.

BACKGROUND: Cerebral malaria (CM) results in significant paediatric death and neurodisability in sub-Saharan Africa. Several different alterations to typical Transcranial Doppler Ultrasound (TCD) flow velocities and waveforms in CM have been described, but mechanistic contributors to these abnormalities are unknown. If identified, targeted, TCD-guided adjunctive therapy in CM may improve outcomes. METHODS: This was a prospective, observational study of children 6 months to 12 years with CM in Blantyre, Malawi recruited between January 2018 and June 2021. Medical history, physical examination, laboratory analysis, electroencephalogram, and magnetic resonance imaging were undertaken on presentation. Admission TCD results determined phenotypic grouping following a priori definitions. Evaluation of the relationship between haemodynamic, metabolic, or intracranial perturbations that lead to these observed phenotypes in other diseases was undertaken. Neurological outcomes at hospital discharge were evaluated using the Paediatric Cerebral Performance Categorization (PCPC) score. RESULTS: One hundred seventy-four patients were enrolled. Seven (4%) had a normal TCD examination, 57 (33%) met criteria for hyperaemia, 50 (29%) for low flow, 14 (8%) for microvascular obstruction, 11 (6%) for vasospasm, and 35 (20%) for isolated posterior circulation high flow. A lower cardiac index (CI) and higher systemic vascular resistive index (SVRI) were present in those with low flow than other groups (p < 0.003), though these values are normal for age (CI 4.4 [3.7,5] l/min/m2, SVRI 1552 [1197,1961] dscm-5m2). Other parameters were largely not significantly different between phenotypes. Overall, 118 children (68%) had a good neurological outcome. Twenty-three (13%) died, and 33 (19%) had neurological deficits. Outcomes were best for participants with hyperaemia and isolated posterior high flow (PCPC 1-2 in 77 and 89% respectively). Participants with low flow had the least likelihood of a good outcome (PCPC 1-2 in 42%) (p < 0.001). Cerebral autoregulation was significantly better in children with good outcome (transient hyperemic response ratio (THRR) 1.12 [1.04,1.2]) compared to a poor outcome (THRR 1.05 [0.98,1.02], p = 0.05). CONCLUSIONS: Common pathophysiological mechanisms leading to TCD phenotypes in non-malarial illness are not causative in children with CM. Alternative mechanistic contributors, including mechanical factors of the cerebrovasculature and biologically active regulators of vascular tone should be explored.

Revisiting Co-trimoxazole Prophylaxis for African Adults in the Era of Antiretroviral Therapy: A Randomized Controlled Clinical Trial.

BACKGROUND: Daily co-trimoxazole is recommended for African adults living with human immunodeficiency virus (HIV) irrespective of antiretroviral treatment, immune status, or disease stage. Benefits of continued prophylaxis and whether co-trimoxazole can be stopped following immune reconstitution are unknown. METHODS: We conducted a randomized controlled trial at 2 sites in Malawi that enrolled adults with HIV with undetectable viral load and CD4 count of >250/mm3 and randomized them to continue daily co-trimoxazole, discontinue daily co-trimoxazole and begin weekly chloroquine, or discontinue daily co-trimoxazole. The primary endpoint was the preventive effect of co-trimoxazole prophylaxis against death or World Health Organization (WHO) HIV/AIDS stage 3-4 events, using Cox proportional hazards modeling, in an intention-to-treat population. RESULTS: 1499 adults were enrolled. The preventive effect of co-trimoxazole on the primary endpoint was 22% (95% CI: -14%-47%; P = .20) versus no prophylaxis and 25% (-10%-48%; P = .14) versus chloroquine. When WHO HIV/AIDS stage 2 events were added to the primary endpoint, preventive effect increased to 31% (3-51%; P = .032) and 32% (4-51%; P = .026), respectively. Co-trimoxazole and chloroquine prophylaxis effectively prevented clinical malaria episodes (3.8 and 3.0, respectively, vs 28/100 person-years; P < .001). CONCLUSIONS: Malawian adults with HIV who immune reconstituted on ART and continued co-trimoxazole prophylaxis experienced fewer deaths and WHO HIV/AIDS stage 3-4 events compared with prophylaxis discontinuation, although statistical significance was not achieved. Co-trimoxazole prevented a composite of death plus WHO HIV/AIDS stage 2-4 events. Given poor healthcare access and lack of routine viral load monitoring, co-trimoxazole prophylaxis should continue in adults on ART after immune reconstitution in sub-Saharan Africa. Clinical Trials Registration. NCT01650558.

Submicroscopic malaria infection is not associated with fever in cross-sectional studies in Malawi.

BACKGROUND: Submicroscopic Plasmodium falciparum infections are widespread in many areas. However, the contribution of these infections to symptomatic malaria is not well understood. This study evaluated whether participants with submicroscopic P. falciparum infections have higher prevalence of fever than uninfected participants in southern Malawi. METHODS: A total of 16,650 children and adults were enrolled in the course of six cross-sectional surveys during the dry season (October-November) and after the rainy season (April-May) between 2012 and 2014 in three districts in southern Malawi. Demographic and socioeconomic data were collected in conjunction with data on clinical histories, use of malaria preventive measures, and anti-malarial medication taken within 2 weeks of the survey. Axillary temperatures were measured, and blood samples were collected for P. falciparum detection by microscopy and PCR. Participants without malaria parasites detected on microscopy but with a positive PCR for P. falciparum were defined as having submicroscopic infection. Fever was defined as having any one of: reported fever in the past 2 weeks, reported fever in the past 48 h, or a temperature of ≥ 37.5 °C measured at the time of interview. RESULTS: Submicroscopic P. falciparum infections and fever were both detected in 9% of the study population. In the final analysis adjusted for clustering within household and enumeration area, having submicroscopic P. falciparum infection was associated with reduced odds of fever in the dry season (odds ratio = 0.52; 95% CI 0.33-0.82); the association in the rainy season did not achieve statistical significance (odds ratio = 1.20; 95% CI 0.91-1.59). The association between submicroscopic infection and fever was consistent across all age groups. When the definition of fever was limited to temperature of ≥ 37.5 °C measured at the time of interview, the association was not statistically significant in either the rainy or dry season. CONCLUSIONS: In this series of cross-sectional studies in southern Malawi, submicroscopic P. falciparum infection was not associated with increased risk of fever. Submicroscopic detection of the malaria parasite is important in efforts to decrease transmission but is not essential for the clinical recognition of malaria disease.

Clinical Implications of Asymptomatic Plasmodium falciparum Infections in Malawi.

Background: Asymptomatic Plasmodium falciparum infections are common in Malawi; however, the implications of these infections for the burden of malaria illness are unknown. Whether asymptomatic infections eventually progress to malaria illness, persist without causing symptoms, or clear spontaneously remains undetermined. We identified asymptomatic infections and evaluated the associations between persistent asymptomatic infections and malaria illness. Methods: Children and adults (N = 120) who presented at a health facility with uncomplicated malaria were followed monthly for 2 years. During follow-up visits, participants with malaria symptoms were tested and, if positive, treated. Samples from all visits were tested for parasites using both microscopy and polymerase chain reaction, and all malaria infections underwent genotyping. Cox frailty models were used to estimate the temporal association between asymptomatic infections and malaria illness episodes. Mixed models were used to estimate the odds of clinical symptoms associated with new versus persistent infections. Results: Participants had a median follow-up time of 720 days. Asymptomatic infections were detected during 23% of visits. Persistent asymptomatic infections were associated with decreased risk of malaria illness in all ages (hazard ratio 0.50, P < .001). When asymptomatic infections preceded malaria illness, newly-acquired infections were detected at 92% of subsequent clinical episodes, independent of presence of persistent infections. Malaria illness among children was more likely due to newly-acquired infections (odds ratio, 1.4; 95% confidence interval, 1.3-1.5) than to persistent infections. Conclusions: Asymptomatic P. falciparum infections are associated with decreased incidence of malaria illness, but do not protect against disease when new infection occurs.

Association Between Age and Plasmodium falciparum Infection Dynamics.

Few data exist on the incidence or duration of natural Plasmodium falciparum infections in high-transmission settings. School-aged children (SAC) carry a disproportionate burden of infections, suggesting either increased incidence or increased duration. We estimated the incidence and duration of unique infections according to age groups. The Mfera Cohort Study (2014-2017) in Malawi had 2 years of follow-up, with 120 participants tested monthly and during sick visits. Blood samples were collected to detect P. falciparum by microscopy and polymerase chain reaction. Positive samples underwent genotyping. Simulation was used to account for high rates of nondetection of infection among low-parasitemia infections, which increase in frequency with age. Adults had significantly fewer unique infections per person per year (median, 2.5) compared with SAC and children younger than 5 years of age (6.3 and 6.6, respectively). Over half of all genotypes were persistent. Infections lasted significantly longer in adults (median, 180 days) and SAC (median, 163 days) compared with children younger than 5 years of age (median, 97 days), after accounting for age-dependent nondetection of infection. SAC acquired new infections at the same rate as children younger than 5 years, but they maintained these infections for longer periods of time, similar to adults. This study provides new insights into P. falciparum infection dynamics that should be considered when designing malaria control strategies.

Net age, but not integrity, may be associated with decreased protection against Plasmodium falciparum infection in southern Malawi.

BACKGROUND: Distribution campaigns for insecticide-treated nets (ITN) have increased the use of ITNs in Malawi, but malaria prevalence remains high even among those using the nets. Previous studies have addressed ITN ownership, insecticide resistance, and frequency of ITN use as possible contributing factors to the high prevalence of malaria infection despite high ITN coverage, but have rarely considered whether the condition of the ITN, or how many people use it, impacts efficacy. This study assessed how ITN integrity, ITN age, and the number of persons sharing a net might mitigate or reduce protective efficacy among self-identified ITN users in Malawi. METHODS: From 2012 to 2014, six cross-sectional surveys were conducted in both the rainy and dry seasons in southern Malawi. Data were collected on ITN use, integrity (number and size of holes), and age. Blood samples for detecting Plasmodium falciparum infection were obtained from reported ITN users over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. The final model controlled for gender, household eaves, and community-level infection prevalence during the rainy season. RESULTS: There were 9646 ITN users with blood samples across six surveys, 15% of whom tested positive for P. falciparum infection. Among children under 5 years old, there was a 50% increased odds of P. falciparum infection among those sleeping under an ITN older than two years, compared to those using an ITN less than 2 years old (OR = 1.50; 95% CI 1.07-2.08). ITN integrity and number of individuals sharing an ITN were not associated with P. falciparum infection. CONCLUSIONS: Older ITNs were associated with higher rates of P. falciparum in young children, which may indicate that insecticide concentrations play a larger role in infection prevention than the physical barrier of an ITN. ITN use was self-reported and the integrity measures lacked the precision of newer methods, suggesting a need for objective measures of ITN use and more precise assessment of ITN integrity.

A clinical trial of enteral Levetiracetam for acute seizures in pediatric cerebral malaria.

BACKGROUND: Acute seizures are common in pediatric cerebral malaria (CM), but usual care with phenobarbital risks respiratory suppression. We undertook studies of enteral levetiracetam (eLVT) to evaluate pharmacokinetics (PK), safety and efficacy including an open-label, randomized controlled trial (RCT) comparing eLVT to phenobarbital. METHODS: Children 24-83 months old with CM were enrolled in an eLVT dose-finding study starting with standard dose (40 mg/kg load, then 30 mg/kg Q12 hours) titrated upward until seizure freedom was attained in 75% of subjects. The RCT that followed randomized children to eLVT vs. phenobarbital for acute seizures and compared the groups on minutes with seizures based upon continuous electroencephalogram. Due to safety concerns, midway through the study children allocated to phenobarbital received the drug only if they continued to have seizures (either clinically or electrographically) after benzodiazepine treatment. Secondary outcomes were treatment failure requiring cross over, coma duration and neurologic sequelae at discharge. PK and safety assessments were also undertaken. RESULTS: Among 30 comatose CM children, eLVT was rapidly absorbed and well-tolerated. eLVT clearance was lower in patients with higher admission serum creatinine (SCr), but overall PK parameters were similar to prior pediatric PK studies. Within 4 h of the first dose, 90% reached therapeutic levels (> 20 µg/mL) and all were above 6 µg/mL. 7/7 children achieved seizure freedom on the initial eLVT dose. Comparing 23 eLVT to 21 phenobarbital patients among whom 15/21 received phenobarbital, no differences were seen for minutes with seizure, seizure freedom, coma duration, neurologic sequelae or death, but eLVT was safer (p = 0.019). Phenobarbital was discontinued in 3/15 due to respiratory side effects. CONCLUSION: Enteral LVT offers an affordable option for seizure control in pediatric CM and is safer than phenobarbital. TRIAL REGISTRATION: NCT01660672 . NCT01982812 .

Brain swelling and death in children with cerebral malaria.

BACKGROUND: Case fatality rates among African children with cerebral malaria remain in the range of 15 to 25%. The key pathogenetic processes and causes of death are unknown, but a combination of clinical observations and pathological findings suggests that increased brain volume leading to raised intracranial pressure may play a role. Magnetic resonance imaging (MRI) became available in Malawi in 2009, and we used it to investigate the role of brain swelling in the pathogenesis of fatal cerebral malaria in African children. METHODS: We enrolled children who met a stringent definition of cerebral malaria (one that included the presence of retinopathy), characterized them in detail clinically, and obtained MRI scans on admission and daily thereafter while coma persisted. RESULTS: Of 348 children admitted with cerebral malaria (as defined by the World Health Organization), 168 met the inclusion criteria, underwent all investigations, and were included in the analysis. A total of 25 children (15%) died, 21 of whom (84%) had evidence of severe brain swelling on MRI at admission. In contrast, evidence of severe brain swelling was seen on MRI in 39 of 143 survivors (27%). Serial MRI scans showed evidence of decreasing brain volume in the survivors who had had brain swelling initially. CONCLUSIONS: Increased brain volume was seen in children who died from cerebral malaria but was uncommon in those who did not die from the disease, a finding that suggests that raised intracranial pressure may contribute to a fatal outcome. The natural history indicates that increased intracranial pressure is transient in survivors. (Funded by the National Institutes of Health and Wellcome Trust U.K.).

A targeted approach for routine viral load monitoring in Malawian adults on antiretroviral therapy.

OBJECTIVES: WHO recommends HIV viral load (VL) testing 6 months after antiretroviral therapy (ART) initiation and every 12 months thereafter, but cost prohibits routine, universal VL testing in many developing countries. We sought to devise a targeted approach to routine VL monitoring that could reduce cost and identify those at low risk for virologic failure (VF). METHODS: We analysed screening data from a clinical trial enrolling adults on ART in Malawi. We identified risk factors associated with VF and employed the Knill-Jones method to assign summary score identifying persons at lower risk for VF. RESULTS: Among 957 adults, prevalence of VF was 9.4%. Factors independently associated with VF included age <38 years (OR 3.44, 95% CI 2.01-5.89), ART duration >2.5 years (OR 2.98, 95% CI 1.79-4.96), ART adherence <95% (OR 1.76, 95% CI 1.06-2.94), CD4 count <200 cells/µl (OR 5.94, 95% CI 3.27-10.78), haemoglobin <13 g/dl (OR 2.76, 95% CI 1.70-4.50) and CD8 count >885 cells/µl (OR 2.10, 95% CI 1.28-3.44). Our VF prediction summary score included all factors above except CD8 count and was fairly accurate with validated area under receiver operating characteristic curve of 0.76. Implementation could reduce VL testing by 65%. CONCLUSION: A simple score incorporating age, ART duration and adherence, and CD4 count can accurately identify adults at low risk for VF in a sub-Saharan African setting. In areas with high ART utilisation and limited VL testing capacity, a targeted approach could optimise routine VL monitoring while identifying adults in need of alternate ART regimens.

Simulation models predict that school-age children are responsible for most human-to-mosquito Plasmodium falciparum transmission in southern Malawi.

BACKGROUND: Malaria persists in some high-transmission areas despite extensive control efforts. Progress toward elimination may require effective targeting of specific human populations that act as key transmission reservoirs. METHODS: Parameterized using molecular-based Plasmodium falciparum infection data from cross-sectional community studies in southern Malawi, a simulation model was developed to predict the proportions of human-to-mosquito transmission arising from (a) children under 5 years old (U5s), (b) school-age children (SAC, 5-15 years), (c) young adults (16-30 years), and (d) adults > 30 years. The model incorporates mosquito biting heterogeneity and differential infectivity (i.e. probability that a blood-fed mosquito develops oocysts) by age and gametocyte density. RESULTS: The model predicted that SAC were responsible for more than 60% of new mosquito infections in both dry and rainy seasons, even though they comprise only 30% of this southern Malawi population. Young adults were the second largest contributors, while U5s and adults over 30 were each responsible for < 10% of transmission. While the specific predicted values are sensitive to the relative infectiousness of SAC, this group remained the most important contributor to mosquito infections under all realistic estimates. CONCLUSIONS: These results suggest that U5 children play a small role compared to SAC in maintaining P. falciparum transmission in southern Malawi. Models that assume biting homogeneity overestimate the importance of U5s. To reduce transmission, interventions will need to reach more SAC and young adults. This publicly available model can be used by others to estimate age-specific transmission contributions in epidemiologically similar sites with local parameter estimates of P. falciparum prevalence and bed net use.

Admission EEG findings in diverse paediatric cerebral malaria populations predict outcomes.

BACKGROUND: Electroencephalography at hospital presentation may offer important insights regarding prognosis that can inform understanding of cerebral malaria (CM) pathophysiology and potentially guide patient selection and risk stratification for future clinical trials. Electroencephalogram (EEG) findings in children with CM in Uganda and Malawi were compared and associations between admission EEG findings and outcome across this diverse population were assessed. Demographic, clinical and admission EEG data from Ugandan and Malawian children admitted from 2009 to 2012 with CM were gathered, and survivors assessed for neurological abnormalities at discharge. RESULTS: 281 children were enrolled (Uganda n = 122, Malawi n = 159). The Malawian population was comprised only of retinopathy positive children (versus 72.5% retinopathy positive in Uganda) and were older (4.2 versus 3.7 years; p = 0.046), had a higher HIV prevalence (9.0 versus 2.8%; p = 0.042), and worse hyperlactataemia (7.4 versus 5.2 mmol/L; p < 0.001) on admission compared to the Ugandan children. EEG findings differed between the two groups in terms of average voltage and frequencies, reactivity, asymmetry, and the presence/absence of sleep architecture. In univariate analyses pooling EEG and outcomes data for both sites, higher average and maximum voltages, faster dominant frequencies, and retained reactivity were associated with survival (all p < 0.05). Focal slowing was associated with death (OR 2.93; 95% CI 1.77-7.30) and a lower average voltage was associated with neurological morbidity in survivors (p = 0.0032). CONCLUSIONS: Despite substantial demographic and clinical heterogeneity between subjects in Malawi and Uganda as well as different EEG readers at each site, EEG findings on admission predicted mortality and morbidity. For CM clinical trials aimed at decreasing mortality or morbidity, EEG may be valuable for risk stratification and/or subject selection.