Diagnosis Of Malaria Research Articles

1383. Malaria Prophylaxis Use In a Travel Clinic, How Are We Doing?

Abstract Background Malaria chemoprophylaxis is indicated for travelers going to geographic areas designated as endemic for malaria. Often persons traveling to their native countries where malaria is present consider themselves immune and decline chemoprophylaxis. This study aimed to evaluate malaria chemoprophylaxis utilization in a travel clinic and whether it is correlated with the patient’s native place. Methods A retrospective study of patients attending a travel clinic between 2021 to 2023. Data were extracted on demographics, trip destinations, trip duration, and, malaria chemoprophylaxis prescribed. Pharmacies were contacted to verify prescription filling. Patients admitted with malaria were analyzed at the same time period. Comparison between groups was made using a chi-square test. p < 0.05 is considered significant. Results One hundred patients were included. Median age 55.5 years (21-80). 62 % (62) were females while 38% were males. There were ninety-four 94 travelers to Africa, 6 to South America, and 1 to Asia. Of the travelers, 44 were US natives while 56 were non-US natives. The median trip duration was 14 and 15 days among US and non-US natives respectively. All 100 patients received prescriptions for malaria prophylaxis: Atovaquone/Proguanil was prescribed to 94, while 6 were given mefloquine. Of the 100 prescriptions, 58 were filled. Of the 44 travelers who were US natives,33/44 (75 %) filled their prescriptions. Among the 56 non-US natives, 25/56 (44 %) filled prescriptions, p -0.002. During the study period, 10 patients (6 females and 4 males) were admitted with a diagnosis of malaria in returning travelers, median age of 54.5 years. The median trip duration was 19 days. All were non-US natives returning from Africa (Nigeria, Ghana, Guinea, and Mali). Only 1/10 patients took mefloquine chemoprophylaxis. All the patients were treated successfully without sequelae. Conclusion In our travel clinic malaria chemoprophylaxis was prescribed to all patients as indicated, US native patients filled their prescriptions significantly more than nonnative patients. Malaria in returning travelers was diagnosed exclusively in non-US natives who did not take malaria chemoprophylaxis. Disclosures All Authors: No reported disclosures

Standardization of DNA extraction from paraffinized spleen samples: molecular diagnosis of human malaria

BackgroundPlasmodium vivax is the main species responsible for human malaria in Brazil, and one of its manifestations is splenic malaria, though there are still challenges in its diagnosis. The present study aimed to standardize Plasmodium sp. DNA extraction from histological slices of spleen and diagnosis using real-time qPCR.MethodsThis study performed a microtomy of a paraffin-embedded spleen as a positive control for P. vivax from a patient who had been previously diagnosed with the parasite. The sample was deparaffinized with xylol and ethanol, then DNA extraction was performed with two commercial kits. qPCR was carried out with the Taqman system for detection of Plasmodium sp. and was made species-specific using PvmtCOX1 gene. From 2015 to 2019, 200 spleen samples were obtained from trauma patients subjected to splenectomy in Manaus, Amazonas. All the samples were tested for cell-free human DNA (cfDNA).ResultsThe deparaffinization and the Plasmodium vivax DNA extraction method was successfully standardized, and the control sample was positive for P. vivax. Of the 200 samples, all qPCRs were negative, but they were positive for human PCR.ConclusionParaffinization is practical and efficient for the preservation of samples, but the formation of bonds between proteins and DNA makes extraction difficult. Despite this, in this study, it was possible to standardize a method of DNA extraction for detecting P. vivax.

IMAGING: a novel automated system for malaria diagnosis by using artificial intelligence tools and a universal low-cost robotized microscope

IntroductionMalaria is one of the most prevalent infectious diseases in sub-Saharan Africa, with 247 million cases reported worldwide in 2021 according to the World Health Organization. Optical microscopy remains the gold standard technique for malaria diagnosis, however, it requires expertise, is time-consuming and difficult to reproduce. Therefore, new diagnostic techniques based on digital image analysis using artificial intelligence tools can improve diagnosis and help automate it.MethodsIn this study, a dataset of 2571 labeled thick blood smear images were created. YOLOv5x, Faster R-CNN, SSD, and RetinaNet object detection neural networks were trained on the same dataset to evaluate their performance in Plasmodium parasite detection. Attention modules were applied and compared with YOLOv5x results. To automate the entire diagnostic process, a prototype of 3D-printed pieces was designed for the robotization of conventional optical microscopy, capable of auto-focusing the sample and tracking the entire slide.ResultsComparative analysis yielded a performance for YOLOv5x on a test set of 92.10% precision, 93.50% recall, 92.79% F-score, and 94.40% mAP0.5 for leukocyte, early and mature Plasmodium trophozoites overall detection. F-score values of each category were 99.0% for leukocytes, 88.6% for early trophozoites and 87.3% for mature trophozoites detection. Attention modules performance show non-significant statistical differences when compared to YOLOv5x original trained model. The predictive models were integrated into a smartphone-computer application for the purpose of image-based diagnostics in the laboratory. The system can perform a fully automated diagnosis by the auto-focus and X-Y movements of the robotized microscope, the CNN models trained for digital image analysis, and the smartphone device. The new prototype would determine whether a Giemsa-stained thick blood smear sample is positive/negative for Plasmodium infection and its parasite levels. The whole system was integrated into the iMAGING smartphone application.ConclusionThe coalescence of the fully-automated system via auto-focus and slide movements and the autonomous detection of Plasmodium parasites in digital images with a smartphone software and AI algorithms confers the prototype the optimal features to join the global effort against malaria, neglected tropical diseases and other infectious diseases.

Endothelial transcriptomic analysis identifies biomarkers of severe and cerebral malaria.

Malaria can quickly progress from an uncomplicated infection into a life-threatening severe disease. However, the unspecificity of early symptoms often makes it difficult to identify patients at high risk of developing severe disease. Additionally, one of the most feared malaria complications - cerebral malaria - is challenging to diagnose, often resulting in treatment delays that can lead to adverse outcomes. To identify candidate biomarkers for the prognosis and/or diagnosis of severe and cerebral malaria, we have analyzed the transcriptomic response of human brain microvascular endothelial cells to erythrocytes infected with Plasmodium falciparum. Candidates were validated in plasma samples from a cohort of pediatric patients with malaria from Mozambique, resulting in the identification of several markers with capacity to distinguish uncomplicated from severe malaria, the most potent being the metallopeptidase ADAMTS18. Two other biomarkers, Angiopoietin-like-4 and Inhibin-βE were able to differentiate children with cerebral malaria within the severe malaria group, showing increased sensitivity after combination in a biomarker signature. The validation of the predicted candidate biomarkers in plasma of children with severe and cerebral malaria underscores the power of this transcriptomic approach and indicates that a specific endothelial response to P. falciparum-infected erythrocytes is linked to the pathophysiology of severe malaria.

Galectins in Protozoan Parasitic Diseases: Potential Applications in Diagnostics and Therapeutics.

Neglected tropical diseases (NTDs) constitute a group of diseases that generally develop in tropical or subtropical climatic conditions and are related to poverty. Within the spectrum of NTDs, diseases caused by protozoa such as malaria, Chagas disease, and leishmaniasis exhibit elevated mortality rates, thereby constituting a substantial public health concern. Beyond their protozoan etiology, these NTDs share other similarities, such as the challenge of control and the lack of affordable, safe, and effective drugs. In view of the above, the need to explore novel diagnostic predictors and therapeutic targets for the treatment of these parasitic diseases is evident. In this context, galectins are attractive because they are a set of lectins bound to β-galactosides that play key roles in a variety of cellular processes, including host-parasite interaction such as adhesion and entry of parasites into the host cells, and participate in antiparasitic immunity in either a stimulatory or inhibitory manner, especially the galectins-1, -2, -3, and -9. These functions bestow upon galectins significant therapeutic prospects in the context of managing and diagnosing NTDs. Thus, the present review aims to elucidate the potential role of galectins in the diagnosis and treatment of malaria, leishmaniasis, and Chagas disease.

Diagnostic performance of ultrasensitive rapid diagnostic test for the detection of Plasmodium falciparum infections in asymptomatic individuals in Kisangani, Northeast Democratic Republic of Congo

BackgroundUltrasensitive rapid diagnostic test (usRDT) was recently developed to improve the detection of low-density Plasmodium falciparum infections. However, its diagnostic performance has not been evaluated in the Democratic Republic of Congo (DRC). This study aims to determine the performance of the usRDT in malaria diagnosis in asymptomatic individuals under field condition in Kisangani, Northeast of DRC.MethodsA community-based cross-sectional study was carried out from June to August 2022 on 312 asymptomatic individuals residing in the city of Kisangani. Capillary blood samples were collected by finger prick for microscopic examination of thick and thin blood film, RDTs, and nested polymerase chain reaction (PCR). Alere™ Malaria Ag P.f usRDT and conventional RDT (cRDT/SD Bioline Malaria Ag P.f) kits were used for the detection of Plasmodium histidine rich protein 2 (HRP2) antigen as a proxy for the presence of P. falciparum. The diagnostic performance of the usRDT was compared with cRDT, microscopy and PCR.ResultsThe prevalence of asymptomatic P. falciparum malaria was 40.4%, 42.0%, 47.1% and 54.2% by cRDT, microscopy, usRDT and PCR, respectively. By using PCR as a reference, usRDT had sensitivity and specificity of 87.0% (95% CI 81.4–91.7) and 100.0% (95% CI 97.5–100.0), respectively, whereas the cRDT had sensitivity and specificity of 74.6% (95% CI 67.3–80.9) and 100% (95% CI 97.1–100.0), respectively. By using microscopy as a reference, usRDT had sensitivity and specificity of 96.9% (95% CI 92.4–99.2) and 89.0% (95% CI 83.5–93.1), respectively, while the cRDT had sensitivity and specificity of 96.2% (95% CI 92.3–98.7) and 100% (95% CI 97.9–100.0), respectively.ConclusionThe usRDT showed better diagnostic performance with higher sensitivity than the cRDT which is currently in use as point-of-care test. Further research is necessary to assess the access and cost-effectiveness of the usRDTs to use for malaria surveillance.

A novel transfer learning-based model for diagnosing malaria from parasitized and uninfected red blood cell images

Malaria represents a potentially fatal communicable illness triggered by the Plasmodium parasite. This disease is transmitted to humans through the bites of Anopheles mosquitoes that carry the infection. This disease has significant and devastating consequences on the health systems of fragile countries, particularly in sub-Saharan Africa. Malaria affects red blood cells by invading and replicating within them, destroying them, and releasing toxic byproducts into the bloodstream. The parasite’s ability to stick and modify the surface of red blood cells can cause them to become sticky, obstructing blood flow in vital organs such as the brain and spleen. Therefore, efficient approaches for the early detection of malaria are critical to saving patients’ lives. The main aim of this study is to develop an efficient model for early malaria diagnosis. We used malaria images based on parasitized and uninfected red blood cells for the study experiments. We applied neural network-based approaches such as Neural Search Architecture Network (NASNet) and compared its performance with machine learning techniques. Moreover, we proposed a novel NNR (NASNet Random forest) method for feature engineering. The proposed NNR approach first extracts spatial features from input malaria images, then class prediction probability features are extracted from these spatial features. The feature set obtained from the data extraction trains machine learning models. Our comprehensive experiments show that the support vector machine outperformed state-of-the-art models, achieving a high-performance score of 99% and having an inference time near 0.025 s. We validated the performance using k-fold cross-validation and optimized the hyperparameters through tuning. Our proposed research has improved the early diagnosis of malaria and can assist medical specialists in reducing the mortality rate.

Rapid, sensitive, and convenient detection of Plasmodium falciparum infection based on CRISPR and its application in detection of asymptomatic infection

Rapid and convenient detection of the Plasmodium in clinically diagnosed individuals and asymptomatically infected populations is essential for global malaria eradication, especially in malaria-endemic African countries where medical equipment and professionals are relatively deficient. Here, we described a CRISPR-based diagnostic for the detection of Plasmodium falciparum, the deadliest and most prevalent species of malaria parasite in Africa, via lateral flow strip readout without the need of nucleic acid extraction. The assay exhibited 100% sensitivity on clinical samples (5 P falciparum) and significant consistency with qPCR test on asymptomatic infection samples (49 P falciparum and 51 non-P. falciparum, Kappa=0.839). An artemisinin-resistant P. falciparum strain and 4 other laboratory-cultured strains can also be detected through this assay, whereas no cross-reactivity with Plasmodium vivax was observed. A 0.001% parasitaemia (corresponding to ∼60 parasites/μL) below the “low parasite density” test threshold (200 parasites/µL) is detectable. Our study demonstrated that direct malaria detection using whole blood on the spot and the detection of both clinical and asymptomatic infections of P. falciparum are feasible. This method is expected to be employed for clinical testing and large-scale community screening in Africa and possibly other places, contributing to the accurate diagnosis and control of malaria.

Effect of Plasmodium Infections on CD4 Cells, Neutrophil and Lymphocytes

Knowledge of malaria-immunity is essential for understanding the pathology, treatment & vaccine production. So, changes in CD4 in malaria patients were studied at a teaching hospital in Enugu, Nigeria. 45 patients on doctor’s provisional diagnosis of malaria were examined for Plasmodium infections and the degree of parasitaemia (0/+/ ++/ & +++). Positive/(+) and negative/(0) samples were thereafter counted for CD4 using Flow Cytometry. CD4 cell count of Plasmodium-negative specimens were within reference ranges (RR): (464-1308); mean value: 835. Fifteen (+) parasitaemia showed lower ranges of CD4 count (502-1282); mean: 678; with immune falls in one (427). 9/12 (++) parasitaemia showed crash in CD4 counts, range: 301- 415; mean: 399. Seven (+++) parasitaemia showed crashes in CD4 counts, range: 160-357; mean: 225. As parasitaemia rises, neutrophils, Total WBC and lymphocyte significantly rise in numeric. Malaria causes immunosuppression; unlike prevailing reports, should accelerate complications in immunodeficients-patients, Haemolytic-anaemia results only from chronic cases. CD4 counts should be a paradigm in malaria investigation.

Length of stay in at-risk areas and time to malaria attack on return

BackgroundExperimental infection with Plasmodium falciparum results in malaria attack within a few days of exposure. However, we have regularly observed malaria attack within a short time after return, regardless of the time spent in an endemic area. We therefore aimed to assess whether the time before return and malaria attack varies according to length of stay. MethodsWe used anonymized data from the French National Reference Centre for Malaria between 2006 and 2016. We analyzed 11,823 cases aged at least 1 year and diagnosed with P. falciparum malaria 1 day to 1 year after returning to France, after a stay of 1 day to 1 year in an at-risk area. ResultsTrips had a median duration of 31 days [IQR: 19–56]. Median time between return from the endemic area and onset of malaria symptoms was 5 days [IQR: 0–10], and the median between return and malaria diagnosis was 9 days [IQR: 5–14]. Times to symptom onset or diagnosis were longer for stays of fewer than 15 days vs 15 days or more (for symptoms: 7 vs 4 days for longer stays, for diagnosis: 11 vs 9 days). For stays longer than 15 days, no variation was observed according to length of stay. ConclusionsAside from at-risk stays of fewer than 15 days, the time between return and malaria attack is constant and rather short, even after long stays. The 2 weeks following return should be considered as a risk period whatever the length of stay in an at-risk area.

Diagnostic value of rapid test for malaria among febrile neonates in a tertiary hospital in North-East Nigeria: a prospective cross-sectional study

ObjectiveThe WHO recommends testing using microscopy or rapid diagnostic test (RDT) before treatment for malaria. However, the use of RDT to diagnose neonatal malaria has not been widely validated with...

Performance of ultra-sensitive malaria rapid diagnostic test to detect Plasmodium falciparum infection in pregnant women in Kinshasa, the Democratic Republic of the Congo

BackgroundLow peripheral parasitaemia caused by sequestration of Plasmodium falciparum in the placenta hampers the diagnosis of malaria in pregnant women, leading to microscopy or conventional rapid diagnostic tests (RDTs) false-negative results. Although mainly asymptomatic, maternal malaria remains harmful to pregnant women and their offspring in endemic settings and must be adequately diagnosed. Ultra-sensitive RDTs (uRDTs) are thought to be more sensitive than RDTs, and their diagnostic performance was assessed in the current study in pregnant women living in Kinshasa, a stable malaria transmission area in the Democratic Republic of the Congo.MethodsTo assess and compare the diagnostic performances of both RDTs and uRDTs, 497 peripheral blood samples were tested using microscopy and quantitative polymerase chain reaction (qPCR) as the index and the reference tests, respectively. The agreement between the different diagnostic tests assessed was estimated by Cohen's Kappa test.ResultsThe median parasite density by qPCR was 292 p/μL of blood [IQR (49.7–1137)]. Using qPCR as the reference diagnostic test, the sensitivities of microscopy, RDT and uRDT were respectively [55.7% (95% CI 47.6–63.6)], [81.7% (95%CI 74.7–87.3)] and [88% (95% CI 81.9–92.6)]. The specificities of the tests were calculated at 98.5% (95% CI 96.6–99.5), 95.2% (95% CI 92.5–97.2) and 94.4% (95% CI 91.4–96.6) for microscopy, RDT and uRDT, respectively. The agreement between qPCR and uRDT was almost perfect (Kappa = 0.82). For parasite density (qPCR) below 100 p/µL, the sensitivity of RDT was 62% (95% CI 47.1–75.3) compared to 68% (95% CI 53.3–80.4) for uRDT. Between 100 and 200 p/µL, the sensitivity of RDT was higher, but still lower compared to uRDT: 89.4% (95% CI 66.8–98.7) for RDT versus 100% (95% CI 82.3–100) for uRDT. In both cases, microscopy was lower, with 20% (95% CI 10–33.7) and 47.3% (95% CI 24.4–71.1) respectively.ConclusionsuRDT has the potential to improve malaria management in pregnant women as it has been found to be slightly more sensitive than RDT in the detection of malaria in pregnant women but the difference was not significant. Microscopy has a more limited value for the diagnosis of malaria during the pregnancy, because of its lower sensitivity.

The provision of malaria services in border districts of four countries in Southern Africa: results from a cross-sectional community assessment of malaria border health posts

BackgroundThe importation of parasites across borders remains a threat to malaria elimination. The Southern African Development Community Malaria Elimination Eight (E8) established 39 border health facilities on 5 key international borders between high and low-burden countries. These clinics aimed to improve access to prevention, diagnosis, and treatment of malaria for residents in border areas and for mobile and migrant populations who frequently cross borders. Studies were conducted in each of the four high-burden E8 countries (Angola, Mozambique, Zambia, and Zimbabwe) to evaluate malaria services in border areas.MethodsCross-sectional surveys were conducted within 30 km of recently established E8 Border Health Posts. Structured questionnaires were administered to randomly selected respondents to assess malaria-related knowledge and behavior, access to malaria prevention, diagnosis and treatment of malaria, and risk factors for malaria associated with local and cross-border travel.ResultsResults showed that most providers followed appropriate guidelines performing blood tests when individuals presented with fever, and that nearly all those who reported a positive blood test received medication. Lack of access to health care due to distance, cost or mistrust of the provider was rare. A minority of respondents reported not receiving timely diagnosis either because they did not seek help, or because they were not offered a blood test when presenting with fever. There was a high level of correct knowledge of causes, symptoms, and prevention of malaria. A majority, of border residents had access to primary prevention against malaria through either long-lasting insecticidal nets (LLINs) or indoor residual spraying (IRS). Cross border travel was common with travellers reporting sleeping outside without protection against malaria.ConclusionsThe study demonstrated the importance of border health facilities in providing access to malaria services. Prevention needs to be improved for people who travel and sleep outdoors. Community health workers can play a key role in providing access to information, testing and treating malaria.

Plasmodium knowlesi (Pk) Malaria: A Review & Proposal of Therapeutically Rational Exchange (T-REX) of Pk-Resistant Red Blood Cells.

Plasmodium knowlesi (Pk) causes zoonotic malaria and is known as the "fifth human malaria parasite". Pk malaria is an emerging threat because infections are increasing and can be fatal. While most infections are in Southeast Asia (SEA), especially Malaysia, travelers frequently visit this region and can present with Pk malaria around the world. So, clinicians need to know (1) patients who present with fever after recent travel to SEA might be infected with Pk and (2) Pk is often misdiagnosed as P. malariae (which typically causes less severe malaria). Here we review the history, pathophysiology, clinical features, diagnosis, and treatment of Pk malaria. Severe disease is most common in adults. Signs and symptoms can include fever, abdominal pain, jaundice, acute kidney injury, acute respiratory distress syndrome, hyponatremia, hyperparasitemia, and thrombocytopenia. Dengue is one of the diseases to be considered in the differential. Regarding pathophysiologic mechanisms, when Pk parasites invade mature red blood cells (RBCs, i.e., normocytes) and reticulocytes, changes in the red blood cell (RBC) surface can result in life-threatening cytoadherence, sequestration, and reduced RBC deformability. Since molecular mechanisms involving the erythrocytic stage are responsible for onset of severe disease and lethal outcomes, it is biologically plausible that manual exchange transfusion (ET) or automated RBC exchange (RBCX) could be highly beneficial by replacing "sticky" parasitized RBCs with uninfected, deformable, healthy donor RBCs. Here we suggest use of special Pk-resistant donor RBCs to optimize adjunctive manual ET/RBCX for malaria. "Therapeutically-rational exchange transfusion" (T-REX) is proposed in which Pk-resistant RBCs are transfused (instead of disease-promoting RBCs). Because expression of the Duffy antigen on the surface of human RBCs is essential for parasite invasion, T-REX of Duffy-negative RBCs-also known as Fy(a-b-) RBCs-could replace the majority of the patient's circulating normocytes with Pk invasion-resistant RBCs (in a single procedure lasting about 2 h). When sequestered or non-sequestered iRBCs rupture-in a 24 h Pk asexual life cycle-the released merozoites cannot invade Fy(a-b-) RBCs. When Fy(a-b-) RBC units are scarce (e.g., in Malaysia), clinicians can consider the risks and benefits of transfusing plausibly Pk-resistant RBCs, such as glucose-6-phosphate dehydrogenase deficient (G6PDd) RBCs and Southeast Asian ovalocytes (SAO). Patients typically require a very short recovery time (<1 h) after the procedure. Fy(a-b-) RBCs should have a normal lifespan, while SAO and G6PDd RBCs may have mildly reduced half-lives. Because SAO and G6PDd RBCs come from screened blood donors who are healthy and not anemic, these RBCs have a low-risk for hemolysis and do not need to be removed after the patient recovers from malaria. T-REX could be especially useful if (1) antimalarial medications are not readily available, (2) patients are likely to progress to severe disease, or (3) drug-resistant strains emerge. In conclusion, T-REX is a proposed optimization of manual ET/RBCX that has not yet been utilized but can be considered by physicians to treat Pk malaria patients.

Detection of Plasmodium falciparum in Saliva and Stool Samples from Children Living in Franceville, a Highly Endemic Region of Gabon.

Due to the difficulty of obtaining blood samples, which is the invasive method that is currently used for the detection of Plasmodium spp., alternative diagnostic sampling methods that are effective and non-invasive are needed, particularly for long-term studies. Saliva and stool samples from malaria-infected individuals contain trace amounts of Plasmodium DNA and therefore could be used as alternatives. Malaria was screened using rapid diagnosis tests and confirmed via microscopy. Nested PCR tests targeting the Plasmodium falciparum-specific STEVOR gene were performed for blood, saliva and stool samples that were positive for malaria. Three hundred sixty-seven (367) children were enrolled and eighty (22.22%) were confirmed to be positive for malaria. Matched blood, saliva and stool samples were available for 35 children. By using blood smears as the gold standard for the diagnosis of malaria, our study indicates that Plasmodium DNA was more detectable in blood (100%) than in saliva (22.86%) and stools (14.29%). Applying qPCR to the STEVOR gene to detect Plasmodium falciparum DNA in saliva and stool samples cannot be considered as an alternative to the current malaria detection processes using blood specimens.

Non-human primate malaria in travellers.

Emerging zoonotic malaria caused by Plasmodium knowlesi, P. cynomolgi and P. inui occurred in humans amid a decline of malaria prevalence in Thailand during the past decade. Diagnosis of non-human primate malaria in ecotourists is challenging. Molecular diagnosis seems to be mandatory such as species-specific PCR and targeted amplicon deep sequencing.

Enhanced effect of seasonal malaria chemoprevention when coupled with nutrients supplementation for preventing malaria in children under 5 years old in Burkina Faso: a randomized open label trial

BackgroundIn rural African settings, most of the children under the coverage of Seasonal Malaria Chemoprevention (SMC) are also undernourished at the time of SMC delivery, justifying the need for packaging malarial and nutritional interventions. This study aimed at assessing the impact of SMC by coupling the intervention with nutrients supplementation for preventing malaria in children less than 5 years old in Burkina Faso.MethodsA randomized trial was carried out between July 2020 and June 2021 in the health district of Nanoro, Burkina Faso. Children (n = 1059) under SMC coverage were randomly assigned to one of the three study arms SMC + Vitamin A (SMC-A, n = 353) or SMC + Vitamin A + Zinc (SMC-AZc, n = 353) or SMC + Vitamin A + PlumpyDoz(tm) (SMC-APd, n = 353)-a medium quantity—lipid-based nutrient supplement (MQ-LNS). Children were followed up for one year that included an active follow-up period of 6 months with scheduled monthly home visits followed by 6 months passive follow-up. At each visit, capillary blood sample was collected for malaria diagnosis by rapid diagnosis test (RDT).ResultsAdding nutritional supplements to SMC had an effect on the incidence of malaria. A reduction of 23% (adjusted IRR = 0.77 (95%CI 0.61–0.97) in the odds of having uncomplicated malaria in SMC-APd arm but not with SMC-AZc arm adjusted IRR = 0.82 (95%CI 0.65–1.04) compare to control arm was observed. A reduction of 52%, adjusted IRR = 0.48 (95%CI 0.23–0.98) in the odds of having severe malaria was observed in SMC-APd arm compared to control arm. Besides the effect on malaria, this combined strategy had an effect on all-cause morbidity. More specifically, a reduction of morbidity odds of 24%, adjusted IRR = 0.76 (95%CI 0.60–0.94) in SMC-APd arm compared to control arm was observed. Unlike clinical episodes, no effect of nutrient supplementation on cross sectional asymptomatic infections was observed.ConclusionAdding nutritional supplements to SMC significantly increases the impact of this intervention for preventing children from malaria and other childhood infections.Trial registration: NCT04238845.

Rapid diagnostic tests for malaria diagnosis in Cameroon: impact of histidine rich protein 2/3 deletions and lactate dehydrogenase gene polymorphism

Malaria rapid diagnostic tests (mRDT) play a vital role in malaria control in endemic areas. In this study, histidine-rich protein (hrp) and lactate dehydrogenase (ldh) genes were genotyped in Plasmodium falciparum (Pf) and Plasmodium ovale (Po) spp. isolates. Deletions in P. falciparum hrp2/3 (pfhrp2/3) proteins and single nucleotide polymorphisms (SNPs) were analyzed. Twenty-four samples were analyzed for pfhrp2/3 gene deletions and 25 for SNPs in ldh gene (18 Pf and 7 Po spp.). Deletions in pfhrp2/3 genes were observed in 1.9% malaria positive isolates. The pfldh gene sequences showed one SNP at codon 272 (D272N) in 22.2% of samples while in Po spp., sequences were 100% similar to P. ovale curtisi but when compared to P. ovale wallikeri reference sequence, SNPs at positions 143 (P143S), 168 (K168N), 204 (V204I) were found. Findings suggest low prevalence in pfhrp2/3 genes and highlight the circulation of P. ovale curtisi in the studies areas.

Multiclass malaria parasite recognition based on transformer models and a generative adversarial network

Malaria is an extremely infectious disease and a main cause of death worldwide. Microscopic examination of thin slide serves as a common method for the diagnosis of malaria. Meanwhile, the transformer models have gained increasing popularity in many regions, such as computer vision and natural language processing. Transformers also offer lots of advantages in classification task, such as Fine-grained Feature Extraction, Attention Mechanism etc. In this article, we propose to assist the medical professionals by developing an effective framework based on transformer models and a generative adversarial network for multi-class plasmodium classification and malaria diagnosis. The Generative Adversarial Network is employed to generate extended training samples from multiclass cell images, with the aim of enhancing the robustness of the resulting model. We aim to optimize plasmodium classification to achieve an exact balance of high accuracy and low resource consumption. A comprehensive comparison of the transformer models to the state-of-the-art methods proves their efficiency in the classification of malaria parasite through thin blood smear microscopic images. Based on our findings, the Swin Transformer model and MobileVit outperform the baseline architectures in terms of precision, recall, F1-score, specificity, and FPR on test set (the data was divided into train: validation: test splits). It is evident that the Swin Transformer achieves superior detection performance (up to 99.8% accuracy), while MobileViT demonstrates lower memory usage and shorter inference times. High accuracy empowers healthcare professionals to conduct precise diagnoses, while low memory usage and short inference times enable the deployment of predictive models on edge devices with limited computational and memory resources.

Evaluation of the Performance of Standard Tests in the Differential Diagnosis of Malaria and Typhoid Fever

Malaria and typhoid fever are microbial conditions that share almost similar symptoms including hyperthermia. These diseases are endemic in sub-Saharan Africa where resources for proper control are scarce and biological diagnosis fundamentally based on direct and indirect screening tests. The present investigation aims to evaluate the performance of the usual tests for the differential diagnosis of malaria and typhoid fever, in connection with a few conducive environmental determinants of hygiene and sanitation. We conducted a descriptive cross-sectional study over a period of three months at the Bangangté District Hospital and the Cliniques Universitaires des Montagnes. The study population consisted of patients presenting with hyperthermia. Participant’s blood and stool specimens were subjected for screening according to standard protocols. The size of the study population was 90, with age average, 36 years. Men were relatively more represented than women (sex ratio1.04). The alleged most commonly water source was the tap (36.7%). Assessment of various tests and temperature displayed positive correlation (R=0.212; P=0.044) between the Plasmodium load and the increased temperature. The Widal-et-Felix test yielded 75% sensitivity, 51% specificity, 90% positive-predictive value and 97% negative-predictive value compared to stool culture for Salmonella Typhi. Concerning the SD Bioline RDT, 79% sensitivity, 70% specificity, 65% positive-predictive value and 82% negative-predictive value compared to the thick blood smear for Plasmodium were recorded. Biological crossed pieces of information (Blood Smear/stool culture) for malaria/typhoid fever co-infection were observed in 7.4% of cases. The rapid diagnostic tests assessment resulted in 34.78% false positives and 17.74% of false-negatives, while the Widal-et-Felix showed 90.74% of false-positives and 3.03% of false-negatives. The Youden index for the Widal-et-Felix (degree of inaccuracy, 0.26, far from 1) implied that this test is not appropriate for the diagnosis of typhoid fever alone.