Cardiovascular Risk from Altered Lipid Profile and Atherogenic Indices in Children with Uncomplicated Plasmodium falciparum Malaria in Owo, Nigeria

The recommendation of the RTS,S/AS01 malaria vaccine for use in children in moderate to high transmission areas by the WHO in 2021 provided another crucial tool in reducing malaria morbidity and mortality. As countries introduce the RTS,S/AS01 vaccine, there is an interest in exploring vaccination schedules that align with existing routine health touchpoints and to optimize vaccine coverage. This study used OpenMalaria, an individual-based, stochastic model of malaria transmission and disease progression, to assess the impact of different vaccination timing schedules and coverage on uncomplicated malaria cases, severe malaria cases, and malaria-related deaths across different archetypal transmission settings. We ran simulations comparing fourth dose protection against infection and timings at 6-, 9-, 12-, 15- and 18-month intervals following the primary series, including exploring ranges of plausible protection assumptions for many of the dose timings. The primary series substantially reduces the malaria burden across transmission settings, regardless of timing of the fourth vaccine dose. For example, at a baseline Plasmodium falciparum prevalence in 2-10year olds (PfPR2-10) of 20%, our modeling suggests that the primary series is responsible for around 73-93% of the total uncomplicated and 74%-92% of severe cases averted regardless of fourth dose timing in perennial settings. Additionally, a fourth dose of the vaccine in this transmission setting could avert additional 8-38% of uncomplicated and 9-36% of severe malaria cases in addition to the primary series alone. While the number of cases averted varies by baseline prevalence, we find potential flexibility in timing this dose, especially when focused on 6 to 12months following the primary series. A fourth dose delivered between 15- and 21-months of age (corresponding to a 6-12month interval after the third dose) with high population coverage will likely avert the largest proportion of cases of uncomplicated malaria, severe malaria, and deaths in perennial settings, across transmission intensities.Therefore, the delivery of the fourth dose of the RTS,S/AS01 vaccine can be tailored to country-specific context and linked to existing health touchpoints to ensure adequate coverage of this dose to optimize its impact.

Malarial retinopathy refers to a constellation of changes seen in severe or complicated malaria cases. These include: retinal whitening, vessel changes-whitening, tramlining, retinal hemorrhages, and papilledema. There are very few Indian studies on this entity. Since retina can be easily visualized by direct ophthalmoscopy, this study was done to determine prevalence of malarial retinopathy among malaria cases and to determine relationship between malarial retinopathy and severity of the disease. The study was done at Indoor and Outdoor Departments of Tropical Medicine, School of Tropical Medicine (STM), Kolkata, with the support of the Department of Ophthalmology, Regional Institute of Ophthalmology (RIO), Medical College, Kolkata. Adult malaria cases, both complicated/severe and uncomplicated, were included. Patients unable or unwilling to cooperate with eye examination, contraindications to tropicamide eye drops (angle closure glaucoma or known allergy to product), severe corneal scarring or cataracts hindering view by ophthalmoscopy, diabetes mellitus, hypertension, intracranial space occupying lesions, epilepsy, alcohol use, chronic renal failure, age > 60 years and any other known ocular/systemic disease that can cause retinopathy changes were excluded. Severe malaria was diagnosed as per the WHO criteria. Cases with acute febrile illness of other causes were taken in control arm, and normal population subjects were taken as controls. All patients were assessed clinically, followed by appropriate laboratory investigations and then direct ophthalmoscopic examination was done. Ocular findings were be collaborated with severity of illness. A total of 71 malaria cases were included in our study. Among them, 12 cases were of severe malaria, and rest of the cases were uncomplicated. Of the 12 severe malaria cases, 8 were Plasmodium vivax, 3 were Plasmodium falciparum, and 1 was mixed. Uncomplicated malaria cases were mostly P. vivax (35 out of 59). Features suggestive of malarial retinopathy were noted in 9 out of 12 cases of severe malaria (75%) and 2 out of 59 cases of uncomplicated malaria (3.4%). We noted two cases of retinal changes-one case of retinal whitening in falciparum malaria and one case of vivax malaria with retinal hemorrhage in the uncomplicated group. Both of the cases subsequently needed admission for recurrent vomiting, reduced urine output, and severe weakness 40 dengue cases were included in control arm of AFI cases-20 DHF cases and 20 cases of DF with warning signs. Among them, retinal hemorrhage was noted in one case of DHF (2.5%). Out of 40 sepsis cases, retinal hemorrhage was seen in one case (2.5%). No retinal changes were noted among 40 other AFI cases which included scrub typhus, enteric fever, chikungunya, and acute viral hepatitis. Also, no abnormality was detected on ophthalmoscopy in 40 healthy individuals. The presence of retinopathy was suggestive of severe malaria (p < 0.05). We found the sensitivity and specificity of malarial retinopathy as a marker of severe malaria to be 75% and 96.6% with a positive predictive value of 81.8%. Malarial retinopathy may serve as an important clinical biomarker for predicting severe malaria. All clinicians should be appropriately trained in performing direct ophthalmoscopy to detect the retinopathy changes.

Intravascular hemolysis accompanies diverse diseases, yet blood-based markers (eg, plasma-free hemoglobin [PFH], haptoglobin, lactate dehydrogenase [LDH], and bilirubin) are variably sensitive, nonspecific, or impractical for point-of-care use. We evaluated urinary carbonic anhydrase 1 (CA1) as a mechanistically grounded, urine-based marker of hemolysis in a multicenter study spanning the United Kingdom, Bangladesh, and Peru. We enrolled 234 participants: healthy adults and adults with inherited anemias (Oxford), newborns in intensive care (London), children and adults with complicated or uncomplicated malaria (Bangladesh), and adults attending rural clinics for various medical reasons (Peru). Urine CA1 and hemoglobin (Hb) were quantified by enzyme-linked immunosorbent assay and immunoblot, with CA1:Hb stoichiometry used to distinguish intravascular hemolysis from urogenital blood contamination. Relationships with PFH, LDH, bilirubin, Hb, C-reactive protein (CRP), and clinical variables were tested using regression, principal component analysis, and decision tree. Reference urine samples were predominantly CA1-negative/Hb-negative. In inherited anemias, urinary CA1 was highest in sickle cell disease and correlated with serum LDH and inversely with blood Hb. In neonates, longitudinal CA1 trajectories stratified infants into physiological, transient, and sustained hemolysis groups; higher CA1 levels were associated with prematurity, elevated CRP and lower white blood cell count. Urinary CA1 was detected in Bangladeshi patients with elevated PFH and in cases of intravascular hemolysis not identified by PFH. Among Peruvian participants, urinary CA1 correlated with raised CRP level, consistent with inflammation being a prohemolytic trigger. To enable rapid and cost-effective testing, a lateral flow device was developed and verified for excellent sensitivity and specificity. Urinary CA1 provides a sensitive and practical readout of intravascular hemolysis suitable for point-of-care testing globally.

Malaria remains a major health burden in sub-Saharan Africa, where traditional vector control methods are hindered by insecticide resistance and evolving mosquito behaviour causing residual transmission. In the BOHEMIA cluster-randomised trial in Kenya, ivermectin mass drug administration (iMDA), delivered once a month for 3 months with approximately 64% population coverage, was shown to reduce malaria incidence by 26%. We aimed to assess the cost-effectiveness of iMDA as a supplementary vector control tool using data from the BOHEMIA trial in Kenya. We did a cost-effectiveness analysis of the BOHEMIA cluster-randomised trial done in Kwale county, Kenya, using a societal perspective to estimate the intervention costs, health system costs, direct household out-of-pocket expenses, and indirect costs from lost wages of iMDA versus a no-intervention scenario. Intervention effectiveness was measured as the number of malaria cases averted and disability-adjusted life-years (DALYs) averted. A decision tree model was developed to simulate the intervention's impact on a broader population. Deterministic and probabilistic sensitivity analyses were performed to assess the robustness of the results, and incremental cost-effectiveness ratios (ICERs) were compared with Kenya's gross domestic product (GDP)-based thresholds. The intervention cost of iMDA was US$11·83 per person. Household out-of-pocket costs averaged $5·85 for uncomplicated malaria cases and $52·23 for severe cases. Productivity loss amounted to $2·18 for uncomplicated and $8·83 for severe cases. The base-case ICER was $905·23 per DALY averted, which was below the threshold of 0·5 × Kenya's GDP per capita ($974·65). In probabilistic analysis (10 000 iterations), the median ICER was $1107·51 per DALY averted (50% credible interval 770·05-1606·77). This study demonstrates that iMDA can be a cost-effective supplementary intervention for malaria control in settings with moderate malaria transmission and good insecticide-treated net coverage, particularly when malaria reduction is greater than 23·62% for children younger than 5 years and opportunities for reducing intervention costs can be identified. This work was funded and supported by Unitaid through the BOHEMIA project.

In vitro antiplasmodial activity, acute toxicity and phytochemical quantification of selected medicinal plants used for the management of uncomplicated malaria in eastern Uganda.

Cerebral malaria (CM) is a common cause of febrile coma among African children. Despite treatment with highly efficacious intravenous artesunate, CM remains associated with high mortality and neurologic sequelae. In a mouse CM model, the glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON) demonstrated robust efficacy as a potential adjuvant therapy. Before testing DON in children with CM, we investigated tolerability in African adults, including individuals with malaria. We conducted an open-label, prospective, dose-escalation, Phase I clinical trial of single dose intravenous DON in Blantyre, Malawi. Participants included healthy adults and adults with uncomplicated malaria, enrolled in dose-cohorts of ten and administered DON at 0.1, 1.0, 5.0, or 10 mg/kg. We assessed adverse events (AEs) and plasma pharmacokinetics. Forty healthy adults and 38 adults with uncomplicated malaria received DON. Transient, asymptomatic creatinine elevation occurred 12 hours post-infusion in 18% of all participants. Nausea and vomiting were uncommon at 0.1 and 1.0 mg/kg but occurred more frequently at 5.0 and 10 mg/kg DON. All DON-related AEs resolved rapidly, without sequelae, and did not significantly differ between healthy and uncomplicated malaria participants. In healthy adults, maximum plasma concentrations increased proportional to dose, but adults with malaria had greater than dose-proportional increases. Terminal half-life ranged from 1.7-4.1 hours. DON was well tolerated in healthy adults and adults with uncomplicated malaria. Higher doses were associated with transient gastrointestinal AEs. Pharmacokinetics were minimally influenced by malaria disease. These results provide critical data to guide dosing strategies for adjunctive DON in children with CM.ClinicalTrials.gov: NCT05478720.

Vaccines, monoclonal antibodies, and long-acting injectables are being developed to prevent Plasmodium falciparum malaria. These therapeutics may target multiple stages of the parasite life cycle; evidence is needed to articulate their benefits with chemoprevention and prioritise candidates for clinical development. We used an individual-based malaria transmission model to estimate the health impact of combining new therapeutics with seasonal malaria chemoprevention (SMC). Our modelling framework used emulator-based methods with models of pre-liver and blood stage therapeutic dynamics. We evaluated the benefit of combining therapeutics with SMC in children under five by estimating reductions in the cumulative incidence of uncomplicated and severe malaria, relative to SMC or the new therapeutic alone, during and five years after deployment. Results showed that new therapeutics may require extended pre-liver stage duration or multi-stage activity to combine with SMC. For three SMC cycles in a high transmission setting, a pre-liver stage therapeutic with partial initial efficacy (>50%) required a protection half-life >230 days to reduce cumulative severe cases by >23% during interventions, and >5% five years after deployment stopped. Longer protection was needed when combined with four or five SMC cycles. And, combining SMC with a multi-stage therapeutic increased public health impact both during and after deployment. These results indicate that combining SMC with malaria therapeutics active against multiple stages of the parasite life cycle can improve the effectiveness of SMC, and highlight the need for clinical development to prioritise multi-stage therapeutics for improved malaria prevention in children.

Malaria and malnutrition are major causes of childhood morbidity and mortality. Most of children receiving Seasonal malaria chemoprevention (SMC) are also generally malnourished during SMC delivery period. This study aimed at assessing the risk of malaria infection in malnourished children, compared to children with an adequate nutritional status (ANS) during the delivery period of SMC intervention in the health district of Nanoro, Burkina Faso. A longitudinal survey of children aged 6-59 months receiving SMC intervention was carried out between 2020 and 2022 in Nanoro, Burkina Faso. WHO online anthro survey tool was used to assess the nutritional status. Included children were stratified into two sub-groups as malnourished from the start of the first SMC round until one month after the last SMC round and those of ANS during that same period. In addition to the monthly home visits, all health care attendance were recorded for all participants. At each visit, socio-anthropometric data were collected. Blood smears were collected for malaria diagnosis by rapid diagnostic test (RDT) and microscopy. The effect of the nutritional status on the occurrence of uncomplicated malaria was assessed using a negative binomial model, with results expressed as incidence risk ratio (IRR). Out of the 425 children included this study, 260 were malnourished, while 165 children had an ANS. Malaria incidence per 1000 child-month were higher in undernutrition (974.47) than in ANS (214.47). Malnourished children were 1.41 times more likely to have t an episode of clinical malaria than children with ANS (IRR 1.42; 95% CI 1.03-1.94; p = 0.028). There was an increased risk of malaria infection in undernourished children compared to children with an adequate nutritional status suggesting the need of combining SMC intervention with nutrients supplementation to achieve best impact for malaria control in food insecure areas.

How does pyronaridine-artesunate compare with other artemisinin-based combination therapies for people with uncomplicated Plasmodium falciparum malaria?

Jacobabad, located in the northern region of Sindh, is characterized by an extremely hot and humid climate and is classified as a malaria-endemic area, with an annual parasite incidence (API) of 31 per 1000 population in 2024. The present study investigates the incidence of malaria among patients admitted to our hospital along with comparison of clinical and haematological profile of severe and uncomplicated malaria in the region and to determine any association with age. To the best of our knowledge, no prior study has systematically documented the malaria burden in this region. A prospective clinical observational study was conducted in Pakistan Airforce Hospital, Shahbaz Base, Jacobabad, Sindh between 2024 to 2025. A total of 260 admitted malaria patients, irrespective of age and gender were included. Cases were categorized into severe and complicated based on WHO criteria. The clinical parameters and haematological profile of severe and uncomplicated cases were compared and data analysed using SPSS v 27. Frequency and percentage were calculated for categorical variables while mean and standard deviation was calculated for numerical variables. Chi square test was applied to find statistical significance. The p-value of ≤ 0.05 was considered statistically significant. Statistical significance of haematological parameters with type of malaria was derived using Kruskal Wallis test while statistical significance of haematological parameters with severity of disease was derived by Mann Whitney U test. Uncomplicated and severe malaria cases were 217 (83.5%) and 43 (16.5%) respectively. Severe malaria was significantly associated with jaundice, bleeding, pallor, respiratory distress, fits, cerebral malaria, anaemia and thrombocytopenia. Overall, case fatality was 16.2% seen in paediatric age group (0.1-15 yrs) and most fatal complication was cerebral malaria. Clinical and haematological parameters serve as prognostic indicators for disease progression and warrant close monitoring to prevent adverse clinical outcomes.

Background and objectivesThe emergence and spread of antimalarial drug resistance threaten malaria control efforts in sub-Saharan Africa. Monitoring the susceptibility of circulating Plasmodium falciparum isolates is essential to inform national treatment guidelines and guide the development of new therapies. To assess the ex vivo susceptibility of P. falciparum field isolates to 14 antimalarials, including withdrawn/unused and currently used drugs, and next-generation agents in Mali.MethodsTwenty-six isolates collected from patients with uncomplicated malaria at three endemic sites (Faladje, Kolle and Bougoula-Hameau) were cultured ex vivo under standardized conditions. Parasites were exposed to 14 drugs, including tafenoquine, N-desethyl-amodiaquine, chloroquine, dihydroartemisinin, lumefantrine, pyronaridine, quinine, sulfadoxine, pyrimethamine, amodiaquine, atovaquone, GNF179, KDU691 and cabamiquine. Susceptibility was measured using fluorescence-based assays with SYBR Green I and Mitotracker dyes, and IC50 values were derived from dose–response curves.ResultsTafenoquine showed a very low potency (IC50 > 1500 nM). Chloroquine exhibited marked inter- and intra-site variability (IC50 ∼50–1300 nM), while N-desethyl-amodiaquine potently inhibited isolates (median IC50 < 20 nM in Faladje and Bougoula-Hameau). Current frontline drugs, dihydroartemisinin (median IC50 < 6 nM), lumefantrine (median IC50 < 50 nM) and pyronaridine (median IC50 < 10 nM), remained highly potent. Quinine showed variable efficacy (IC50 ∼75–1000 nM). Chemoprevention agents sulfadoxine and pyrimethamine displayed high IC50 values (median IC50 > 1000 and >2000 nM). Atovaquone and amodiaquine consistently inhibited all isolates (IC50 < 10 nM). Next-generation compounds cabamiquine and GNF179 demonstrated consistently strong activity (IC50 < 10 nM), while KDU691 showed moderate activity (median IC50 18–22 nM).ConclusionsWhile current frontline therapies remain effective, reduced activity of chemopreventive antimalarials supports the need for continued surveillance to detect early signs of resistance in Mali. The potent activity of next-generation candidates (cabamiquine and GNF179) supports their potential for further clinical development and field deployment.

Background: In Cameroon, artemisinin-based combination therapy (ACT) and parasitological confirmation before treatment are the national standards for managing uncomplicated malaria. However, effective implementation at the point of care is critical for patient outcomes and preventing drug resistance. This study evaluated the real-world clinical diagnostic approaches and the adequacy of antimalarial prescriptions for uncomplicated malaria in the Buea Health District (BHD). Methods: A cross-sectional study was conducted from February to April 2022 in 31 public and private health facilities in the BHD. Data were collected from 251 patients presenting with fever or a history of fever who were diagnosed with uncomplicated malaria. Variables included patient demographics, symptoms, diagnostic test results (RDT/microscopy), and details of the prescribed antimalarial. Prescription adequacy was assessed against national guidelines. Results: The majority of patients were female (56.6%) with a mean age of 18.8 years. Fever (81.3%) and headache (86.1%) were the most common symptoms. Most patients (93.2%) underwent a parasitological test, with microscopy being the most frequent. Overall, 46.2% had a positive thick blood smear and 22.3% a positive RDT. Artemisinin-based combination therapy was prescribed in 93.1% of cases, with Artemether-Lumefantrine (AL) being the most common (53.4%), followed by Artesunate-Amodiaquine (ASAQ) (36.8%). However, a significant portion of ACT treatments (35.5%) were initiated before laboratory confirmation. Documentation of prescription details was high for galenic form and duration (93.2%) but lower for posology (84.1%). Crucially, only 42.6% of all malaria cases were managed in full adherence to national guidelines. Conclusion: While diagnostic testing and ACT use for uncomplicated malaria are high in the BHD, a substantial gap remains between practice and policy. The prevalent use of presumptive treatment and the suboptimal overall adherence to guidelines highlight the need for targeted interventions, including continued prescriber training and strengthened supply chain management, to optimize malaria case management and preserve ACT efficacy.

This study compared malaria parasite intensity in mono-infection and in co-infection with typhoid among febrile patients attending selected health facilities in Wukari, Nigeria. A total of 418 clinically diagnosed febrile patients were enrolled, and from each, blood and stool samples were collected for blood film examination and stool culture, respectively. Overall, 75.3% of malaria-positive cases had low parasite intensity, whereas 24.7% had higher parasite density, with a statistically significant difference (p &lt; 0.001). Among the 83 patients with malaria mono-infection, low-intensity (+) parasitemia was more frequent than high-intensity parasitemia, indicating that uncomplicated malaria is more commonly associated with lower parasite density. In contrast, among co-infected cases, 68.9% of patients with high malaria intensity were co-infected with Salmonella (typhoid), while 31.1% of patients with low malaria intensity were co-infected, with an overall p value &lt; 0.011. The odds ratio of 6.766 indicates that individuals with high malaria intensity have approximately sevenfold higher odds of developing typhoid fever compared to those with low malaria intensity. These findings suggest that elevated malaria parasite density is strongly associated with typhoid co-infection and underscore the need for healthcare providers to maintain heightened vigilance for severe malaria presentations in patients with concurrent typhoid infection. The study concludes that a comprehensive control program targeting vector breeding sites and improving sanitation and public health education is essential to reduce the burden of malaria–typhoid co-infection in the study area.

Algeria has been certified as malaria-free since 2019 by WHO and last indigenous case was reported in May 2013; however, imported cases remain a concern for possible for reintroduction. This study aimed to describes the epidemiological, clinical, and therapeutic characteristics of imported malaria cases in the Tizi-Ouzou between 2018 and 2024. A retrospective descriptive study was conducted in the Department of Infectious Diseases at the University Hospital of Tizi-Ouzou. Data were collected from hospital registers and archived medical records. Only laboratory-confirmed cases, diagnosed by microscopic examination of Giemsa-stained blood smears, were included. Variables included demographics, travel history, Plasmodium species, incubation period, clinical presentation, disease severity, laboratory findings, treatment, preventive measures, and outcomes. Among 106 individuals screened, 16 were confirmed as imported malaria (positivity rate 15.1%). Annual cases fluctuated, with a notable increase from 2022 to 2024, reaching 40% positivity in 2024. Most patients were men (87.5%) and adults aged 20-50 yrs (87.5%), mainly Algerian nationals returning from West Africa. Plasmodium falciparum accounted for 87.5% of cases, often with low parasitemia (< 4 % in 68.8%). No patient had used chemoprophylaxis. Fever with chills and sweats was the most common symptom (92.9%). Uncomplicated malaria representes 78.6% of cases, while 21.4% were severe. The main biological abnormalities were anemia (92.8%), thrombocytopenia (42.8%), and hepatic cytolysis (43%). Mefloquine was the most prescribed treatment (71.4%). Imported malaria in Tizi-Ouzou is characterized by P. falciparum predominance, absence of chemoprophylaxis, short post-travel incubation, and travel-linked seasonality. Strengthening pre-travel counseling, improving prophylaxis, uptake, and enhancing clinician awareness are crucial to prevent severe disease and reduce the risk of malaria reintroduction in Algeria.

Amodiaquine-artesunate is one of the recommended options by the Angolan National Malaria Control Program for the treatment of uncomplicated malaria and for malaria seasonal chemoprevention. CYP2C8 is a critical enzyme in the metabolism of amodiaquine. The CYP2C8 gene harbors alleles coding for less active enzymes that have been linked to amodiaquine-associated adverse events. In this work, we analyzed the prevalences of the CYP2C8 main alleles in a sample of the Angolan population. We found an expected robust frequency of a very-low-activity allele, CYP2C8*2 (18.2%) but also the unusual presence of alleles CYP2C8*3 (1%) and CYP2C8*4 (0.5%). Together, these alleles were seen in a non-negligible group of Plasmodium falciparum malaria patients and children under amodiaquine-based therapies and prophylactic strategies.

The efficacy of artesunate + amodiaquine (ASAQ) and artemether + lumefantrine (AL) for treating malaria was investigated in Madagascar in 2020. A randomized parallel-group study was conducted at four health centers (Antsenavolo, Vohitromby, and Matanga in the southeastern region and Ankazomborona in the northwestern region). The therapeutic efficacy and safety of ASAQ and AL were assessed using the WHO protocol, with a 28-day follow-up period. Children aged 6 months to 14 years with uncomplicated Plasmodium falciparum (P. falciparum) malaria were randomly assigned to receive either ASAQ or AL. Genotyping assays for the pfK13 gene were conducted on P. falciparum isolates obtained from dry blood samples collected on Day 0. Of 765 enrolled patients, 709 (92.7%) reached the study endpoint. Among the per-protocol population, crude adequate clinical and parasitological response (ACPR) rates were 99%, 99%, 100%, and 100% for Antsenavolo, Vohitromby, Matanga, and Ankazomborona, respectively, in the ASAQ group and 98%, 91%, 90%, and 100% for the same locations, respectively, in the AL group. Polymerase chain reaction-corrected ACPR rates were 100% for the ASAQ group at all study sites, whereas for the AL group, they were 98.8% in Antsenavolo, 97.6% in Vohitromby, 100% in Matanga, and 100% in Ankazomborona. Day 3 slide positivity rates were 0%, 1%, 1%, and 0% for Antsenavolo, Vohitromby, Matanga, and Ankazomborona, respectively. During follow-up, mild and moderate adverse events, including gastrointestinal issues (abdominal pain and vomiting) and headache, were reported in 10.2% (72/709) of patients. Of 727 samples successfully analyzed for pfK13, no mutation associated with artemisinin resistance was observed. The study results reveal that ASAQ and AL remain safe and efficacious for treating uncomplicated P. falciparum malaria in Madagascar.

Malaria remains a major cause of morbidity and mortality in sub-Saharan Africa. Severe Plasmodium falciparum malaria is primarily driven by parasite sequestration in deep vascular tissues. Standard diagnostic tools, such as peripheral parasitaemia determination, do not always reflect the total parasite burden. Plasma Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP2) level has emerged as a potential biomarker for estimating total parasite biomass, which may better reflect disease severity than peripheral parasitaemia. However, it is still unclear how PfHRP2-estimated parasite biomass varies across different clinical malaria syndromes, how well it predicts severity compared to circulating parasitaemia, and how prior antimalarial treatment influences these measures. Addressing these gaps is critical to improving severity assessment and guiding timely interventions. Data from 118 children diagnosed with cerebral malaria (CM, n = 58), severe malaria anaemia (SMA, n = 28), or uncomplicated malaria (UM, n = 32) were collected in five referral hospitals in Accra from 2012 to 2016. Total parasite burden (PTot) was estimated using PfHRP2-based biomass measurement while the circulating parasite burden (PCir) was determined from peripheral parasite density. The sequestered parasite burden (PSeq), which represent the difference between PTot and PCir, was also evaluated. Additionally, the impact of prior antimalarial treatment on parasite burden was assessed. PTot and PSeq were consistently higher than PCir in severe malaria syndromes. In UM, PTot and PCir were similar, while the median PCir was lower in CM than in UM, suggesting greater sequestration in severe disease. After regaining consciousness, CM patients exhibited decreased PTot and PSeq values compared to their values at initial clinical evaluation. Higher PSeq estimates were associated with coma. Prior antimalarial treatment also reduced PCir but did not significantly change PTot. PfHRP2-derived total parasite biomass demonstrated a stronger association with severe malaria syndromes than peripheral parasitaemia. Accounting for prior antimalarial treatment is essential, as it may lower circulating parasite counts without affecting total biomass. Incorporating total parasite biomass assessments into clinical evaluation could enhance disease severity classification and inform timely interventions in endemic regions.

Artemisinin-combination therapies (ACTs) are now recommended for the treatment of uncomplicated malaria caused by Plasmodium vivax, the parasite responsible for the majority of malaria infections outside of Africa. We sequence the genomes of 206 P. vivax parasites collected from Cambodian malaria patients and show that more than 80% of them carry a DNA deletion located immediately downstream of the multidrug resistance 1 gene (mdr1) protein-coding sequence. This 837 bp deletion overlaps with a different deletion present at low frequency in South American isolates, suggesting a functional role despite not altering the coding sequence of mdr1. Using RNA sequencing, we show that these deletions alter the transcripts expressed from mdr1 and result in mRNAs with different 3' untranslated regions. In Cambodian isolates, the deletion was significantly associated with a higher level of mdr1 mRNA, a lower ex vivo susceptibility to mefloquine, and increased in frequency in Cambodia since the introduction of mefloquine as ACT partner drug. Overall, these findings indicate that a common deletion of a non-coding sequence affects the transcription, stability, or translation of mdr1 in P. vivax parasites and could mediate reduced susceptibility to antimalarial drug(s) currently used for the treatment of uncomplicated vivax malaria.

Dihydroartemisinin (DHA), a first-line treatment for uncomplicated malaria, has demonstrated antitumor activity against a variety of human cancers, emphasizing its potential for repurposing as an anticancer agent. However, its short half-life and poor bioavailability hinder its application in cancer therapy. We previously demonstrated that the molecular hybridization of DHA with bile acids (BAs) enhances its anticancer activity by improving stability and reducing toxicity. Based on this rationale, here, we designed and synthesized a library of DHA-based hybrids through conjugation with ursodeoxycholic and chenodeoxycholic bile acids. Different conjugation sites and both cleavable and non-cleavable linkages were explored to enable a comprehensive structure–activity relationship analysis. The resulting BA-DHA hybrids were evaluated in vitro for their anticancer activity against HCT116 and RKO colorectal cancer cell lines. As a result of the synergistic effect of the linker type and conjugation site, the BA-DHA hybrids synthesized via click chemistry emerged as the most active compounds in both cell lines, displaying 2- to 20-fold higher activity than the parent DHA. Mechanistic investigations further revealed that the click-derived BA-DHA hybrids possess enhanced anticancer activity and antimetastatic potential, achieving comparable or even superior efficacy to the parent compound at markedly lower concentrations.