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Søgeord (malaria) valgt.
1220 emner vises.
Malaria Journal, 18.04.2024
Tilføjet 18.04.2024
Abstract Background Conventional natural killer (cNK) cells play an important role in the innate immune response by directly killing infected and malignant cells and by producing pro- and anti-inflammatory cytokines. Studies on their role in malaria and its complications have resulted in conflicting results. Methods Using the commonly used anti-NK1.1 depletion antibodies (PK136) in an in-house optimized experimental model for malaria-associated acute respiratory distress syndrome (MA-ARDS), the role of cNK cells was investigated. Moreover, flow cytometry was performed to characterize different NK cell populations. Results While cNK cells were found to be dispensable in the development of MA-ARDS, the appearance of a NK1.1+ cell population was observed in the lungs upon infection despite depletion with anti-NK1.1. Detailed characterization of the unknown population revealed that this population consisted of a mixture of monocytes and macrophages that bind the anti-NK1.1 antibody in an aspecific way. This aspecific binding may occur via Fcγ receptors, such as FcγR4. In contrast, in vivo depletion using anti-NK1.1 antibodies was proved to be specific for cNK cells. Conclusion cNK cells are dispensable in the development of experimental MA-ARDS. Moreover, careful flow cytometric analysis, with a critical mindset in relation to potential aspecific binding despite the use of commercially available Fc blocking reagents, is critical to avoid misinterpretation of the results.
Læs mere Tjek på PubMedMalaria Journal, 17.04.2024
Tilføjet 17.04.2024
Abstract Background To gain a deeper understanding of protective immunity against relapsing malaria, this study examined sporozoite-specific T cell responses induced by a chemoprophylaxis with sporozoite (CPS) immunization in a relapsing Plasmodium cynomolgi rhesus macaque model. Methods The animals received three CPS immunizations with P. cynomolgi sporozoites, administered by mosquito bite, while under two anti-malarial drug regimens. Group 1 (n = 6) received artesunate/chloroquine (AS/CQ) followed by a radical cure with CQ plus primaquine (PQ). Group 2 (n = 6) received atovaquone-proguanil (AP) followed by PQ. After the final immunization, the animals were challenged with intravenous injection of 104 P. cynomolgi sporozoites, the dose that induced reliable infection and relapse rate. These animals, along with control animals (n = 6), were monitored for primary infection and subsequent relapses. Immunogenicity blood draws were done after each of the three CPS session, before and after the challenge, with liver, spleen and bone marrow sampling and analysis done after the challenge. Results Group 2 animals demonstrated superior protection, with two achieving protection and two experiencing partial protection, while only one animal in group 1 had partial protection. These animals displayed high sporozoite-specific IFN-γ T cell responses in the liver, spleen, and bone marrow after the challenge with one protected animal having the highest frequency of IFN-γ+ CD8+, IFN-γ+ CD4+, and IFN-γ+ γδ T cells in the liver. Partially protected animals also demonstrated a relatively high frequency of IFN-γ+ CD8+, IFN-γ+ CD4+, and IFN-γ+ γδ T cells in the liver. It is important to highlight that the second animal in group 2, which experienced protection, exhibited deficient sporozoite-specific T cell responses in the liver while displaying average to high T cell responses in the spleen and bone marrow. Conclusions This research supports the notion that local liver T cell immunity plays a crucial role in defending against liver-stage infection. Nevertheless, there is an instance where protection occurs independently of T cell responses in the liver, suggesting the involvement of the liver\'s innate immunity. The relapsing P. cynomolgi rhesus macaque model holds promise for informing the development of vaccines against relapsing P. vivax.
Læs mere Tjek på PubMedMalaria Journal, 17.04.2024
Tilføjet 17.04.2024
Abstract Background Malaria remains a significant global health burden affecting millions of people, children under 5 years and pregnant women being most vulnerable. In 2019, the World Health Organization (WHO) endorsed the introduction of RTS,S/AS01 malaria vaccine as Phase IV implementation evaluation in three countries: Malawi, Kenya and Ghana. Acceptability and factors influencing vaccination coverage in implementing areas is relatively unknown. In Malawi, only 60% of children were fully immunized with malaria vaccine in Nsanje district in 2021, which is below 80% WHO target. This study aimed at exploring factors influencing uptake of malaria vaccine and identify approaches to increase vaccination. Methods In a cross-sectional study conducted in April–May, 2023, 410 mothers/caregivers with children aged 24–36 months were selected by stratified random sampling and interviewed using a structured questionnaire. Vaccination data was collected from health passports, for those without health passports, data was collected using recall history. Regression analyses were used to test association between independent variables and full uptake of malaria vaccine. Results Uptake of malaria vaccine was 90.5% for dose 1, but reduced to 87.6%, 69.5% and 41.2% for dose 2, 3, and 4 respectively. Children of caregivers with secondary or upper education and those who attended antenatal clinic four times or more had increased odds of full uptake of malaria vaccine [OR: 2.43, 95%CI 1.08–6.51 and OR: 1.89, 95%CI 1.18–3.02], respectively. Children who ever suffered side-effects following immunization and those who travelled long distances to reach the vaccination centre had reduced odds of full uptake of malaria vaccine [OR: 0.35, 95%CI 0.06–0.25 and OR: 0.30, 95%CI 0.03–0.39] respectively. Only 17% (n = 65) of mothers/caregivers knew the correct schedule for vaccination and 38.5% (n = 158) knew the correct number of doses a child was to receive. Conclusion Only RTS,S dose 1 and 2 uptake met WHO coverage targets. Mothers/caregivers had low level of information regarding malaria vaccine, especially on numbers of doses to be received and dosing schedule. The primary modifiable factor influencing vaccine uptake was mother/caregiver knowledge about the vaccine. Thus, to increase the uptake Nsanje District Health Directorate should strengthen communities’ education about malaria vaccine. Programmes to strengthen mother/caregiver knowledge should be included in scale-up of the vaccine in Malawi and across sub-Saharan Africa.
Læs mere Tjek på PubMedMalaria Journal, 17.04.2024
Tilføjet 17.04.2024
Abstract Background Malaria remains a burden globally, with the African region accounting for 94% of the overall disease burden and deaths in 2019. It is the major cause of morbidity and mortality among children in Nigeria. Though different environmental factors have been assessed to influence the distribution and transmission of malaria vectors, there is a shortage of information on how they may influence malaria transmission among under-fives in Nigeria. Methods This study was based on the secondary data analysis of the Nigeria Malaria Indicator Survey 2021. The study sample comprised 10,645 women (aged 15–49) who delivered a child in the 2 years preceding the survey. The study was restricted to under-fives. Logistic regression was used to identify factors associated with the risk of malaria. Results There was a positive association between the risk of malaria and heard/seen malaria messages in the last 6 months (AOR 1.39, 95% CI 1.19–1.62), houses with walls built using rudimentary materials (AOR = 1.38, 95% CI 1.04–1.83), at least 6 children living in the house (AOR 1.22, 95% CI 1.00–1.49), children being 1 or 2 years old was associated with increased odds (AOR 1.89, 95% CI 1.50–2.34 and AOR 1.89, 95% CI 1.52–2.36), children from households with only treated nets (AOR 1.23, 95% CI 1.04–1.46) and those from the North West or South East regions (AOR 1.50, 95% CI 1.10–2.05 and AOR 1.48, 95% CI 1.01–2.16), respectively. All other predictors were not associated with the risk of malaria. Conclusion The factors associated with the risk of malaria in this study included sleeping under treated mosquito nets, the age of the children, residing in the northwest and southeast regions, wall construction material, 6 children and above in the household and hearing/seen malaria messages in the last 6 months. Continuous health education and public health interventions, such as the provision of LLITNs, will reduce the risk of malaria and improve the health and well-being of children under 5 years of age.
Læs mere Tjek på PubMedMalaria Journal, 17.04.2024
Tilføjet 17.04.2024
Abstract Background Achieving effective control and elimination of malaria in endemic regions necessitates a comprehensive understanding of local mosquito species responsible for malaria transmission and their susceptibility to insecticides. Methods The study was conducted in the highly malaria prone Ujina Primary Health Center of Nuh (Mewat) district of Haryana state of India. Monthly entomological surveys were carried out for adult mosquito collections via indoor resting collections, light trap collections, and pyrethrum spray collections. Larvae were also collected from different breeding sites prevalent in the region. Insecticide resistance bioassay, vector incrimination, blood meal analysis was done with the collected vector mosquitoes. Results A total of 34,974 adult Anopheles mosquitoes were caught during the survey period, out of which Anopheles subpictus was predominant (54.7%). Among vectors, Anopheles stephensi was predominant (15.5%) followed by Anopheles culicifacies (10.1%). The Human Blood Index (HBI) in the case of An. culicifacies and An. stephensi was 6.66 and 9.09, respectively. Vector incrimination results revealed Plasmodium vivax positivity rate of 1.6% for An. culicifacies. Both the vector species were found resistant to DDT, malathion and deltamethrin. Conclusion The emergence of insecticide resistance in both vector species, compromises the effectiveness of commonly used public health insecticides. Consequently, the implementation of robust insecticide resistance management strategies becomes imperative. To effectively tackle the malaria transmission, a significant shift in vector control strategies is warranted, with careful consideration and adaptation to address specific challenges encountered in malaria elimination efforts.
Læs mere Tjek på PubMedMalaria Journal, 17.04.2024
Tilføjet 17.04.2024
Abstract Background Rapid diagnostic tests (RDTs) play a significant role in expanding case management in peripheral healthcare systems. Histidine-rich protein-2 (HRP2) antigen detection RDTs are predominantly used to diagnose Plasmodium falciparum infection. However, the evolution and spread of P. falciparum parasite strains with deleted hrp2/3 genes, causing false-negative results, have been reported. This study assessed the diagnostic performance of HRP2-detecting RDTs for P. falciparum cases and the prevalence of pfhrp2/3 deletions among symptomatic patients seeking malaria diagnosis at selected health facilities in southern Ethiopia. Methods A multi-health facilities-based cross-sectional study was conducted on self-presenting febrile patients seeking treatment in southern Ethiopia from July to September 2022. A purposive sampling strategy was used to enroll patients with microscopically confirmed P. falciparum infections. A capillary blood sample was obtained to prepare a blood film for microscopy and a RDT using the SD Bioline™ Malaria Pf/Pv Test. Dried blood spot samples were collected for further molecular analysis. DNA was extracted using gene aid kits and amplification was performed using nested PCR assay. Exon 2 of hrp2 and hrp3, which are the main protein-coding regions, was used to confirm its deletion. The diagnostic performance of RDT was evaluated using PCR as the gold standard test for P. falciparum infections. Results Of 279 P. falciparum PCR-confirmed samples, 249 (89.2%) had successful msp-2 amplification, which was then genotyped for hrp2/3 gene deletions. The study revealed that pfhrp2/3 deletions were common in all health centres, and it was estimated that 144 patients (57.8%) across all health facilities had pfhrp2/3 deletions, leading to false-negative PfHRP2 RDT results. Deletions spanning exon 2 of hrp2, exon 2 of hrp3, and double deletions (hrp2/3) accounted for 68 (27.3%), 76 (30.5%), and 33 (13.2%) of cases, respectively. The study findings revealed the prevalence of P. falciparum parasites lacking a single pfhrp2-/3-gene and that both genes varied across the study sites. This study also showed that the sensitivity of the SD Bioline PfHRP2-RDT test was 76.5% when PCR was used as the reference test. Conclusion This study confirmed the existence of widespread pfhrp2/3- gene deletions, and their magnitude exceeded the WHO-recommended threshold (> 5%). False-negative RDT results resulting from deletions in Pfhrp2/3- affect a country’s attempts at malaria control and elimination. Therefore, the adoption of non-HRP2-based RDTs as an alternative measure is required to avoid the consequences associated with the continued use of HRP-2-based RDTs, in the study area in particular and in Ethiopia in general.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 17.04.2024
Tilføjet 17.04.2024
Abstract Pathogens such as Plasmodium, Babesia, and Theileria invade and multiply within host red blood cells, leading to the pathological consequences of malaria, babesiosis and theileriosis. Establishing continuous in vitro culture systems and suitable animal models is crucial for studying these pathogens. This review spotlights the B. duncani “in culture-in mouse (ICIM)” model as a promising resource for advancing research on the biology, pathogenicity, and virulence of intraerythrocytic parasites. The model offers practical benefits, encompassing well-defined culture conditions, ease of manipulation and a well-annotated genome. Moreover, B. duncani serves as a surrogate system for drug discovery, facilitating the evaluation of new antiparasitic drugs in vitro and in animals, elucidating their modes of action, and uncovering potential resistance mechanisms. The B. duncani ICIM model thus emerges as a multifaceted tool with profound implications, promising advancements in our understanding of parasitic biology and shaping the development of future therapies.
Læs mere Tjek på PubMedJanko, M. M., Araujo, A. L., Ascencio, E. J., Guedes, G. R., Vasco, L. E., Santos, R. O., Damasceno, C. P., Medrano, P. G., Chacon-Uscamaita, P. R., Gunderson, A. K., OMalley, S., Kansara, P. H., Narvaez, M. B., Coombes, C., Pizzitutti, F., Salmon-Mulanovich, G., Zaitchik, B. F., Mena, C. F., Lescano, A. G., Barbieri, A. F., Pan, W. K.
BMJ Open, 16.04.2024
Tilføjet 16.04.2024
IntroductionUnderstanding human mobility’s role in malaria transmission is critical to successful control and elimination. However, common approaches to measuring mobility are ill-equipped for remote regions such as the Amazon. This study develops a network survey to quantify the effect of community connectivity and mobility on malaria transmission. MethodsWe measure community connectivity across the study area using a respondent driven sampling design among key informants who are at least 18 years of age. 45 initial communities will be selected: 10 in Brazil, 10 in Ecuador and 25 in Peru. Participants will be recruited in each initial node and administered a survey to obtain data on each community’s mobility patterns. Survey responses will be ranked and the 2–3 most connected communities will then be selected and surveyed. This process will be repeated for a third round of data collection. Community network matrices will be linked with each country’s malaria surveillance system to test the effects of mobility on disease risk. Ethics and disseminationThis study protocol has been approved by the institutional review boards of Duke University (USA), Universidad San Francisco de Quito (Ecuador), Universidad Peruana Cayetano Heredia (Peru) and Universidade Federal Minas Gerais (Brazil). Results will be disseminated in communities by the end of the study.
Læs mere Tjek på PubMedMichelle L. Gatton, David Smith, Cielo Pasay, Karen Anderson, Selam Mihreteab, Hugo O. Valdivia, Juan F. Sanchez, Khalid B. Beshir, Jane Cunningham, Qin Cheng
International Journal of Infectious Diseases, 16.04.2024
Tilføjet 16.04.2024
The emergence of mutant Plasmodium falciparum parasites with pfhrp2 and pfhrp3 deletions poses a major threat to the utility of histidine rich protein-2 (HRP2)-based malaria rapid diagnostic tests (RDTs), the mainstay diagnostic tool for detecting falciparum malaria in resource-limited settings. These gene-deleted parasites do not express HRP2/3 and are therefore undetectable by HRP2-based RDTs leading to false-negative results. Mutant parasites have now been reported from 40 of the 47 countries where investigations have been conducted [1].
Læs mere Tjek på PubMedBMC Infectious Diseases, 16.04.2024
Tilføjet 16.04.2024
Abstract Severe malaria is not routinely considered when evaluating a febrile patient in the postoperative setting. Common bacterial infections, along with adverse drug reactions, are the usual differential concerns. We present a case of severe malaria emerging unexpectedly eight days after routine craniotomy.
Læs mere Tjek på PubMedMalaria Journal, 14.04.2024
Tilføjet 14.04.2024
Abstract Background While Plasmodium falciparum and Plasmodium vivax cause the majority of malaria cases and deaths, infection by Plasmodium malariae and other Plasmodium species also causes morbidity and mortality. Current understanding of these infections is limited in part by existing point-of-care diagnostics that fail to differentiate them and have poor sensitivity for low-density infections. Accurate diagnosis currently requires molecular assays performed in well-resourced laboratories. This report describes the development of a P. malariae diagnostic assay that uses rapid, isothermal recombinase polymerase amplification (RPA) and lateral-flow-strip detection. Methods Multiple combinations of custom RPA primers and probes were designed using publicly available P. malariae genomic sequences, and by modifying published primer sets. Based on manufacturer RPA reaction conditions (TwistDx nfo kit), an isothermal assay was optimized targeting the multicopy P. malariae 18S rRNA gene with 39 °C incubation and 30-min run time. RPA product was visualized using lateral strips (FAM-labeled, biotinylated amplicon detected by a sandwich immunoassay, visualized using gold nanoparticles). Analytical sensitivity was evaluated using 18S rRNA plasmid DNA, and clinical sensitivity determined using qPCR-confirmed samples collected from Tanzania, Ethiopia, and the Democratic Republic of the Congo. Results Using 18S rRNA plasmid DNA, the assay demonstrates a detection limit of 10 copies/µL (~ 1.7 genome equivalents) and 100% analytical specificity. Testing in field samples showed 95% clinical sensitivity and 88% specificity compared to qPCR. Total assay time was less than 40 min. Conclusion Combined with simplified DNA extraction methods, the assay has potential for future field-deployable, point-of-care use to detect P. malariae infection, which remains largely undiagnosed but a neglected cause of chronic malaria. The assay provides a rapid, simple readout on a lateral flow strip without the need for expensive laboratory equipment.
Læs mere Tjek på PubMedMalaria Journal, 12.04.2024
Tilføjet 12.04.2024
Abstract Background The emergence of resistance to artemisinin-based combination therapy necessitates the search for new, more potent antiplasmodial compounds, including herbal remedies. The whole extract of Maytenus senegalensis has been scientifically investigated for potential biological activities both in vitro and in vivo, demonstrating strong antimalarial activity. However, there is a lack of data on the electrocardiographic effects of M. senegalensis in humans, which is a crucial aspect in the investigation of malaria treatment. Assessing the electrocardiographic effects of M. senegalensis is essential, as many anti-malarial drugs can inadvertently prolong the QT interval on electrocardiograms. Therefore, the study\'s objective was to evaluate the electrocardiographic effects of M. senegalensis in healthy adult volunteers. Methods This study is a secondary analysis of an open-label single-arm dose escalation. Twelve healthy eligible Tanzanian males, aged 18 to 45, were enrolled in four study dose groups. A single 12-lead electrocardiogram (ECG) was performed at baseline and on days 3, 7, 14, 28, and 56. Results No QTcF adverse events occurred with any drug dose. Only one volunteer who received the highest dose (800 mg) of M. senegalensis experienced a moderate transient change (△QTcF > 30 ms; specifically, the value was 37 ms) from baseline on day 28. There was no difference in maximum QTcF and maximum △QTcF between volunteers in all four study dose groups. Conclusions A four-day regimen of 800 mg every 8 h of M. senegalensis did not impact the electrocardiographic parameters in healthy volunteers. This study suggests that M. senegalensis could be a valuable addition to malaria treatment, providing a safer alternative and potentially aiding in the battle against artemisinin-resistant malaria. The results of this study support both the traditional use and the modern therapeutic potential of M. senegalensis. They also set the stage for future research involving larger and more diverse populations to explore the safety profile of M. senegalensis in different demographic groups. This is especially important considering the potential use of M. senegalensis as a therapeutic agent and its widespread utilization as traditional medicine. Trial registration ClinicalTrials.gov, NCT04944966. Registered 30 June 2021-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04944966?term=kamaka&draw=2&rank=1
Læs mere Tjek på PubMedRhea J. Longley, Josephine Malinga, Eva Hesping, Edwin Sutanto, Sophia M. DonVito, Michal Kucharski, Damian A. Oyong, Julie M.J. Verhoef, Esrah Du, Elizabeth Villasis, Kioko Mwikali
Trends in Parasitology, 12.04.2024
Tilføjet 12.04.2024
On 18–22 February this year, the seventh Molecular Approaches to Malaria Conference (MAM) was held in Lorne, Australia. A total of 431 delegates were welcomed to the conference by co-chairs Matthew Dixon [University of Melbourne and Walter and Eliza Hall Institute of Medical Research (WEHI)], Denise Doolan (University of Queensland), Michelle Boyle (Burnet Institute), and Chris Tonkin (WEHI), and to the country by the Eastern Maar Aboriginal Corporation. Jean-Luc Bodmer (Bill and Melinda Gates Foundation) commenced the scientific talks with his keynote on new tools and strategies for malaria elimination and was followed by a heartfelt tribute to the late Dominic Kwiatowski by Julian Rayner (University of Cambridge).
Læs mere Tjek på PubMedThayne H. Dickey, Niraj H. Tolia
Trends in Parasitology, 11.04.2024
Tilføjet 11.04.2024
Recently, Day et al. identified a receptor-binding site on the malaria parasite protein PfCyRPA that binds the host sugar Neu5Ac, and they found that disrupting this interaction impedes parasite growth. A map of the receptor-binding site identifies an attractive target for antimalarial vaccines and therapeutics.
Læs mere Tjek på PubMedMalaria Journal, 10.04.2024
Tilføjet 10.04.2024
Abstract Background Artemisinin-based combination therapy (ACT) has been a major contributor to the substantial reductions in global malaria morbidity and mortality over the last decade. In Tanzania, artemether-lumefantrine (AL) was introduced as the first-line treatment for uncomplicated Plasmodium falciparum malaria in 2006. The World Health Organization (WHO) recommends regular assessment and monitoring of the efficacy of the first-line treatment, specifically considering that artemisinin resistance has been confirmed in the Greater Mekong sub-region. This study\'s main aim was to assess the efficacy and safety of AL for treating uncomplicated P. falciparum malaria in Tanzania. Methods This was a single-arm prospective antimalarial drug efficacy trial conducted in four of the eight National Malaria Control Programme (NMCP) sentinel sites in 2019. The trial was carried out in outpatient health facilities in Karume-Mwanza region, Ipinda-Mbeya region, Simbo-Tabora region, and Nagaga-Mtwara region. Children aged six months to 10 years with microscopy confirmed uncomplicated P. falciparum malaria who met the inclusion criteria were recruited based on the WHO protocol. The children received AL (a 6-dose regimen of AL twice daily for three days). Clinical and parasitological parameters were monitored during follow-up over 28 days to evaluate drug efficacy. Results A total of 628 children were screened for uncomplicated malaria, and 349 (55.6%) were enrolled between May and September 2019. Of the enrolled children, 343 (98.3%) completed the 28-day follow-up or attained the treatment outcomes. There were no early treatment failures; recurrent infections during follow-up were common at two sites (Karume 29.5%; Simbo 18.2%). PCR-corrected adequate clinical and parasitological response (ACPR) by survival analysis to AL on day 28 of follow-up varied from 97.7% at Karume to 100% at Ipinda and Nagaga sites. The commonly reported adverse events were cough, skin pallor, and abdominal pain. The drug was well tolerated, and no serious adverse event was reported. Conclusion This study showed that AL had adequate efficacy and safety for the treatment of uncomplicated falciparum malaria in Tanzania in 2019. The high recurrent infections were mainly due to new infections, highlighting the potential role of introducing alternative artemisinin-based combinations that offer improved post-treatment prophylaxis, such as artesunate-amodiaquine (ASAQ).
Læs mere Tjek på PubMedMalaria Journal, 10.04.2024
Tilføjet 10.04.2024
Abstract Background Ghana is among the top 10 highest malaria burden countries, with about 20,000 children dying annually, 25% of which were under five years. This study aimed to produce interactive web-based disease spatial maps and identify the high-burden malaria districts in Ghana. Methods The study used 2016–2021 data extracted from the routine health service nationally representative and comprehensive District Health Information Management System II (DHIMS2) implemented by the Ghana Health Service. Bayesian geospatial modelling and interactive web-based spatial disease mapping methods were employed to quantify spatial variations and clustering in malaria risk across 260 districts. For each district, the study simultaneously mapped the observed malaria counts, district name, standardized incidence rate, and predicted relative risk and their associated standard errors using interactive web-based visualization methods. Results A total of 32,659,240 malaria cases were reported among children
Læs mere Tjek på PubMedMakoto SaitoPornpimon WilaisrisakMupawjay PimanpanarakJacher Viladpai-NguenMoo Kho PawUrairat KoesukwiwatJoel TarningNicholas J. WhiteFrancois NostenRose McGready1Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand2Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom3Division of Infectious Diseases, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, Tokyo, Japan4Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, Audrey Odom John
Antimicrobial Agents And Chemotherapy, 10.04.2024
Tilføjet 10.04.2024
Mark P. NelderRachel SchatsHendrik N. PoinarAmanda CookeMegan B. BrickleyaEnteric, Zoonotic and Vector-Borne Diseases, Health Protection, Public Health Ontario, Toronto, ON M5G 1M1, CanadabLaboratory for Human Osteoarchaeology, Faculty of Archaeology, Leiden University, 2333 CC Leiden, The NetherlandscDepartment of Anthropology, McMaster University, Hamilton, ON L8S 4L9, CanadadDepartment of Biochemistry, McMaster University, Hamilton, ON L8S 4L9, CanadaeMcMaster Ancient DNA Centre, Department of Anthropology, McMaster University, Hamilton, ON L8S 4L9, Canada
Proceedings of the National Academy of Sciences, 10.04.2024
Tilføjet 10.04.2024
Proceedings of the National Academy of Sciences, Volume 121, Issue 15, April 2024.
Læs mere Tjek på PubMedQiwei YuYing QuLiqiang ZhangXin YaoJing YangSiyuan ChenHui LiuQihao WangMengfan WuJunpei TaoChenghu ZhouIsiaka Lukman AlageSuhong LiuaDepartment of Geography, State Key Laboratory of Remote Sensing Science, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, ChinabState Key Laboratory of Resources and Environmental Information System, Institute of Geographical Science and Natural Resources, Chinese Academy of Sciences, Beijing 100101, ChinacSpace Research and Development Division, African Regional Centre for Space Science and Technology Education in English Ile ife, Ile ife, Osun 220282, Nigeria
Proceedings of the National Academy of Sciences, 10.04.2024
Tilføjet 10.04.2024
Proceedings of the National Academy of Sciences, Volume 121, Issue 15, April 2024.
Læs mere Tjek på PubMedMalaria Journal, 9.04.2024
Tilføjet 9.04.2024
Malaria Journal, 9.04.2024
Tilføjet 9.04.2024
Abstract Background Malaria remains a major global health problem often worsened by political instability and armed conflict. The purpose of the study was to explore community knowledge, attitudes and practices on malaria prevention, and to understand the burden of malaria and health-seeking behaviours of caregivers of children under-five in conflict-affected communities of the South West and Littoral Regions of Cameroon. Methods A cross-sectional survey involving internally displaced persons (IDPS), host population, and their children under-five was conducted across 80 communities. The survey was conducted from May to June 2021. Participants were interviewed using a structured questionnaire. Malaria prevalence for children under-five was determined using rapid diagnostic tests (RDT) on blood samples. Association between variables and displacement status was measured using chi square test and multivariate logistic regression model was fitted to identify factors associated with adequate knowledge on malaria prevention. Results A total of 2386 adults participated in the study and 1543 RDTs were conducted for children under-five. Adequate levels of knowledge and attitudes on malaria prevention was recorded among 1258 (52.9%) of the participants, with very strong evidence to suggest the level to be higher among the host (59.5%) compared to the IDPs (49.5%) and returnees (39.7%) (p
Læs mere Tjek på PubMedMalaria Journal, 9.04.2024
Tilføjet 9.04.2024
Abstract Background Anopheles gambiae, the major malaria mosquito in sub-Saharan Africa, feed largely indoors at night. Raising a house off the ground with no barriers underneath reduces mosquito-house entry. This experiment tested whether walling off the space under an elevated hut affects mosquito-hut entry. Methods Four inhabited experimental huts, each of which could be moved up and down, were used in rural Gambia. Nightly collections of mosquitoes were made using light traps and temperature and carbon dioxide levels monitored indoors and outdoors using loggers. Each night, a reference hut was kept at ground level and three huts raised 2 m above the ground; with the space under the hut left open, walled with air-permeable walls or solid walls. Treatments were rotated every four nights using a randomized block design. The experiment was conducted for 32 nights. Primary measurements were mosquito numbers and indoor temperature in each hut. Results A total of 1,259 female Anopheles gambiae sensu lato were collected in the hut at ground level, 655 in the hut with an open ground floor, 981 in the hut with air-permeable walls underneath and 873 in the hut with solid walls underneath. Multivariate analysis, adjusting for confounders, showed that a raised hut open underneath had 53% fewer mosquitoes (95% CI 47–58%), those with air-permeable walls underneath 24% fewer (95% CI 9–36%) and huts with solid walls underneath 31% fewer (95% CI 24–37%) compared with a hut on the ground. Similar results were found for Mansonia spp. and total number of female mosquitoes, but not for Culex mosquitoes where hut entry was unaffected by height or barriers. Indoor temperature and carbon dioxide levels were similar in all huts. Conclusion Raising a house 2 m from the ground reduces the entry of An. gambiae and Mansonia mosquitoes, but not Culex species. The protective effect of height is reduced if the space underneath the hut is walled off.
Læs mere Tjek på PubMedMalaria Journal, 9.04.2024
Tilføjet 9.04.2024
Abstract Background In sub-Saharan Africa (SSA), Plasmodium falciparum causes most of the malaria cases. Despite its crucial roles in disease severity and drug resistance, comprehensive data on Plasmodium falciparum genetic diversity and multiplicity of infection (MOI) are sparse in SSA. This study summarizes available information on genetic diversity and MOI, focusing on key markers (msp-1, msp-2, glurp, and microsatellites). The systematic review aimed to evaluate their influence on malaria transmission dynamics and offer insights for enhancing malaria control measures in SSA. Methods The review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Two reviewers conducted article screening, assessed the risk of bias (RoB), and performed data abstraction. Meta-analysis was performed using the random-effects model in STATA version 17. Results The review included 52 articles: 39 cross-sectional studies and 13 Randomized Controlled Trial (RCT)/cohort studies, involving 11,640 genotyped parasite isolates from 23 SSA countries. The overall pooled mean expected heterozygosity was 0.65 (95% CI: 0.51–0.78). Regionally, values varied: East (0.58), Central (0.84), Southern (0.74), and West Africa (0.69). Overall pooled allele frequencies of msp-1 alleles K1, MAD20, and RO33 were 61%, 44%, and 40%, respectively, while msp-2 I/C 3D7 and FC27 alleles were 61% and 55%. Central Africa reported higher frequencies (K1: 74%, MAD20: 51%, RO33: 48%) than East Africa (K1: 46%, MAD20: 42%, RO33: 31%). For msp-2, East Africa had 60% and 55% for I/C 3D7 and FC27 alleles, while West Africa had 62% and 50%, respectively. The pooled allele frequency for glurp was 66%. The overall pooled mean MOI was 2.09 (95% CI: 1.88–2.30), with regional variations: East (2.05), Central (2.37), Southern (2.16), and West Africa (1.96). The overall prevalence of polyclonal Plasmodium falciparum infections was 63% (95% CI: 56–70), with regional prevalences as follows: East (62%), West (61%), Central (65%), and South Africa (71%). Conclusion The study shows substantial regional variation in Plasmodium falciparum parasite genetic diversity and MOI in SSA. These findings suggest a need for malaria control strategies and surveillance efforts considering regional-specific factors underlying Plasmodium falciparum infection.
Læs mere Tjek på PubMedMalaria Journal, 7.04.2024
Tilføjet 7.04.2024
Abstract Background The use of artemisinin-based combination therapy (ACT) is recommended by the World Health Organization for the treatment of uncomplicated falciparum malaria. Artemether-lumefantrine (AL) is the most widely adopted first-line ACT for uncomplicated malaria in sub-Saharan Africa (SSA), including mainland Tanzania, where it was introduced in December 2006. The WHO recommends regular assessment to monitor the efficacy of the first-line treatment specifically considering that artemisinin partial resistance was reported in Greater Mekong sub-region and has been confirmed in East Africa (Rwanda and Uganda). The main aim of this study was to assess the efficacy and safety of AL for the treatment of uncomplicated falciparum malaria in mainland Tanzania. Methods A single-arm prospective anti-malarial drug efficacy trial was conducted in Kibaha, Mlimba, Mkuzi, and Ujiji (in Pwani, Morogoro, Tanga, and Kigoma regions, respectively) in 2018. The sample size of 88 patients per site was determined based on WHO 2009 standard protocol. Participants were febrile patients (documented axillary temperature ≥ 37.5 °C and/or history of fever during the past 24 h) aged 6 months to 10 years. Patients received a 6-dose AL regimen by weight twice a day for 3 days. Clinical and parasitological parameters were monitored during 28 days of follow-up to evaluate the drug efficacy and safety. Results A total of 653 children were screened for uncomplicated malaria and 349 (53.7%) were enrolled between April and August 2018. Of the enrolled children, 345 (98.9%) completed the 28 days of follow-up or attained the treatment outcomes. There were no early treatment failures, but recurrent infections were higher in Mkuzi (35.2%) and Ujiji (23%). By Kaplan–Meier analysis of polymerase chain reaction (PCR) uncorrected adequate clinical and parasitological response (ACPR) ranged from 63.4% in Mkuzi to 85.9% in Mlimba, while PCR-corrected ACPR on day 28 varied from 97.6% in Ujiji to 100% in Mlimba. The drug was well tolerated; the commonly reported adverse events were cough, runny nose, and abdominal pain. No serious adverse event was reported. Conclusion This study showed that AL had adequate efficacy and safety for the treatment of uncomplicated falciparum malaria. The high number of recurrent infections were mainly due to new infections, indicating the necessity of utilizing alternative artemisinin-based combinations, such as artesunate amodiaquine, which provide a significantly longer post-treatment prophylactic effect.
Læs mere Tjek på PubMedAlhassan, J. A. K., Wills, O.
BMJ Open, 6.04.2024
Tilføjet 6.04.2024
BackgroundThe last 3 years have witnessed global health challenges, ranging from the pandemics of COVID-19 and mpox (monkeypox) to the Ebola epidemic in Uganda. Public health surveillance is critical for preventing these outbreaks, yet surveillance systems in resource-constrained contexts struggle to provide timely disease reporting. Although community health workers (CHWs) support health systems in low-income and middle-income countries (LMICs), very little has been written about their role in supporting public health surveillance. This review identified the roles, impacts and challenges CHWs face in public health surveillance in 25 LMICs. MethodsWe conducted a scoping review guided by Arksey and O’Malley’s framework. We exported 1,156 peer-reviewed records from Embase, Global Health and PubMed databases. After multiple screenings, 29 articles were included in the final review. ResultsCHWs significantly contribute to public health surveillance in LMICs including through contact tracing and patient visitation to control major infectious diseases such as HIV/AIDS, malaria, tuberculosis, Ebola, neglected tropical diseases and COVID-19. Their public health surveillance roles typically fall into four main categories including community engagement; data gathering; screening, testing and treating; and health education and promotion. The use of CHWs in public health surveillance in LMICs has been impactful and often involves incorporation of various technologies leading to improved epidemic control and disease reporting. Nonetheless, use of CHWs can come with four main challenges including lack of education and training, lack of financial and other resources, logistical and infrastructural challenges as well as community engagement challenges. ConclusionCHWs are important stakeholders in surveillance because they are closer to communities than other healthcare workers. Further integration and training of CHWs in public health surveillance would improve public health surveillance because CHWs can provide health data on ‘hard-to-reach’ populations. CHWs’ work in public health surveillance would also be greatly enhanced by infrastructural investments.
Læs mere Tjek på PubMedPeter F. Billingsley, Thomas L. Richie, Salim Abdulla, Mitoha Ondo’o Ayekaba, Claudia A. Daubenberger, Guíllermo A. Garcia, Stephen L. Hoffman
Trends in Parasitology, 6.04.2024
Tilføjet 6.04.2024
The Equatorial Guinea Malaria Vaccine Initiative (EGMVI) highlights how long-term African government and international energy industry investment, plus novel partnerships, can enable clinical development of vaccines in Africa, for Africa. We review achievements and challenges of this pioneering, award-winning, public–private partnership which offers a model for future Africa-centric clinical research and development (R&D).
Læs mere Tjek på PubMedThirumalaisamy P. Velavan, Wim A. Fleischmann, Peter G. Kremsner
International Journal of Infectious Diseases, 5.04.2024
Tilføjet 5.04.2024
Malaria is a major life-threatening vector-borne disease caused by the genus Plasmodium. It is common in the tropics and subtropics, especially in Africa, where considerable efforts are made to reduce its incidence, and to eliminate it from endemic countries as well as preventing its re-emergence in countries that have been declared malaria-free. To date 104 countries, including Kazakhstan, have reached the status of being malaria-free [1]. Nonetheless, in 2022, 84 malaria endemic countries had an estimated 249 million malaria cases, a 5 million increase compared to 2021 [2], and still posing a major burden on human health and health care systems in many countries.
Læs mere Tjek på PubMedMalaria Journal, 4.04.2024
Tilføjet 4.04.2024
Abstract Background Despite remarkable progress in malaria burden reduction, malaria continues to be a major public health problem globally. Ethiopia has been distributing long-lasting insecticidal nets (LLINs) for free and nationwide distribution was completed in 2016. However, evidence suggests that the utilization of LLINs varies from setting to setting and from time to time due to different factors, and up-to-date evidence is required for LLIN related decision-making. Hence, this study was designed to assess LLIN utilization and its determinants in the Southern Nations, Nationalities, and People’s Region (SNNPR) of Ethiopia. Methods A community-based cross-sectional study was conducted in Southern Ethiopia in 2019. Using multi-stage sampling, a total of 2466 households were included. The region was stratified based on the annual malaria index as high, moderate, low, and free strata. Cluster sampling was then applied to select households from high, moderate, and low strata. Data on LLIN ownership, utilization and different determinant factors were collected using household questionnaire. SurveyCTO was used to collect data and data was managed using Stata 15. Descriptive statistics and multilevel mixed-effects logistic regression were performed to identify the determinants of utilization of LLINs. Effect measures were reported using adjusted odds ratio (AOR) with 95% CI. Results From a total of 2466 households, 48.7% of households had at least one LLIN. LLIN adequacy based on family size was 23% while it was15.7% based on universal access and 29.2% based on sleeping space. From 1202 households that possessed LLIN(s), 66.0% of households reported that they slept under LLIN the night preceding the survey. However, when the total population in all surveyed households were considered, only 22.9% of household members slept under LLIN the night preceding the survey. Malaria endemicity, educational status, wealth status, and knowledge about malaria were associated with LLINs utilization. In addition, reasons for non-use included perceived absence of malaria, side effects of LLIN, conditions of LLINs, inconvenient space and low awareness. Conclusion Low LLIN coverage and low utilization were noted. A low level of utilization was associated with malaria endemicity, wealth status and level of awareness. Distribution of LLIN and continuous follow-up with community awareness creation activities are vital to improve coverage and utilization of LLINs, and to ensure the country’s malaria elimination goal.
Læs mere Tjek på PubMedMalaria Journal, 4.04.2024
Tilføjet 4.04.2024
Abstract Background Plasmodium ovale malaria is usually considered a tropical infectious disease associated with low morbidity and mortality. However, severe disease and death have previously been reported. Case presentation A case of severe P. ovale malaria in a healthy Caucasian man with a triangle splenic infarction and clinical progression towards Acute Respiratory Distress Syndrome was reported despite a rapid response to oral chloroquine treatment with 24-h parasitaemia clearance. Conclusion Plasmodium ovale malaria is generally considered as a benign disease, with low parasitaemia. However, severe disease and death have occasionally been reported. It is important to be aware that occasionally it can progress to serious illness and death even in immunocompetent individuals.
Læs mere Tjek på PubMedMalaria Journal, 3.04.2024
Tilføjet 3.04.2024
Abstract Background Artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) are the currently recommended first- and second-line therapies for uncomplicated Plasmodium falciparum infections in Togo. This study assessed the efficacy of these combinations, the proportion of Day3-positive patients (D3 +), the proportion of molecular markers associated with P. falciparum resistance to anti-malarial drugs, and the variable performance of HRP2-based malaria rapid diagnostic tests (RDTs). Methods A single arm prospective study evaluating the efficacy of AL and DP was conducted at two sites (Kouvé and Anié) from September 2021 to January 2022. Eligible children were enrolled, randomly assigned to treatment at each site and followed up for 42 days after treatment initiation. The primary endpoint was polymerase chain reaction (PCR) adjusted adequate clinical and parasitological response (ACPR). At day 0, samples were analysed for mutations in the Pfkelch13, Pfcrt, Pfmdr-1, dhfr, dhps, and deletions in the hrp2/hrp3 genes. Results A total of 179 and 178 children were included in the AL and DP groups, respectively. After PCR correction, cure rates of patients treated with AL were 97.5% (91.4–99.7) at day 28 in Kouvé and 98.6% (92.4–100) in Anié, whereas 96.4% (CI 95%: 89.1–98.8) and 97.3% (CI 95%: 89.5–99.3) were observed at day 42 in Kouvé and Anié, respectively. The cure rates of patients treated with DP at day 42 were 98.9% (CI 95%: 92.1–99.8) in Kouvé and 100% in Anié. The proportion of patients with parasites on day 3 (D3 +) was 8.5% in AL and 2.6% in DP groups in Anié and 4.3% in AL and 2.1% DP groups in Kouvé. Of the 357 day 0 samples, 99.2% carried the Pfkelch13 wild-type allele. Two isolates carried nonsynonymous mutations not known to be associated with artemisinin partial resistance (ART-R) (A578S and A557S). Most samples carried the Pfcrt wild-type allele (97.2%). The most common Pfmdr-1 allele was the single mutant 184F (75.6%). Among dhfr/dhps mutations, the quintuple mutant haplotype N51I/C59R/S108N + 437G/540E, which is responsible for SP treatment failure in adults and children, was not detected. Single deletions in hrp2 and hrp3 genes were detected in 1/357 (0.3%) and 1/357 (0.3%), respectively. Dual hrp2/hrp3 deletions, which could affect the performances of HRP2-based RDTs, were not observed. Conclusion The results of this study confirm that the AL and DP treatments are highly effective. The absence of the validated Pfkelch13 mutants in the study areas suggests the absence of ART -R, although a significant proportion of D3 + cases were found. The absence of dhfr/dhps quintuple or sextuple mutants (quintuple + 581G) supports the continued use of SP for IPTp during pregnancy and in combination with amodiaquine for seasonal malaria chemoprevention. Trial registration: ACTRN12623000344695.
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 3.04.2024
Tilføjet 3.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4 Pages: 627-630
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 1-2
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 3-10
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 11-16
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 17-29
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 44-53
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 54-64
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 65-72
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 73-81
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 82-93
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.04.2024
Tilføjet 2.04.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 4_Suppl Pages: 94-100
Læs mere Tjek på PubMedMalaria Journal, 1.04.2024
Tilføjet 1.04.2024
Abstract Background As part of implementation quality standards, community distributors are expected to ensure that only age-eligible children (aged 3–59 months) receive seasonal malaria chemoprevention (SMC) medicines during monthly campaigns. There is uncertainty about the extent to which SMC medicines are administered to ineligible children. This study aimed to assess the magnitude of this occurrence, while exploring the factors associated with it across nine states where SMC was delivered in Nigeria during the 2022 round. Methods This analysis was based on data from representative end-of-round SMC household surveys conducted in nine SMC-implementing states in Nigeria. Data of 3299 age-ineligible children aged > 5 years and their caregivers were extracted from the survey dataset. Prevalence of receipt of SMC medicines by ineligible children was described by child-, caregiver- and SMC-related factors. Mixed-effects multivariable logistic regression models were fitted to explore the factors associated with ineligible receipt of SMC medicines. Results 30.30% (95% CI 27.80–32.90) of ineligible children sampled received at least one dose of SMC medicines in 2022, the majority (60.60%) of whom were aged 5–6 years while the rest were aged 7–10 years. There were lower odds of an age-ineligible child receiving SMC among caregivers who had knowledge of SMC age eligibility (OR: 0.53, 95% CI 0.37–0.77, p
Læs mere Tjek på PubMedMalaria Journal, 29.03.2024
Tilføjet 29.03.2024
Abstract Background Diversification of artemisinin-based combination therapy (ACT) is suggested as one of the strategies that can be used to contain artemisinin resistance. Artesunate-amodiaquine (ASAQ) is one of the artemisinin-based combinations that can be used in the diversification strategy as an alternative first-line treatment for uncomplicated malaria in mainland Tanzania. There is however limited data on the efficacy of ASAQ in mainland Tanzania. This study assessed the efficacy of ASAQ for treatment of uncomplicated Plasmodium falciparum malaria in selected sentinel sites for therapeutic efficacy studies in mainland Tanzania. Methods Between December 2018 and March 2020, children aged between 6 months and 10 years, attending at Nagaga, Mkuzi, and Mlimba primary health facilities, and with suspected uncomplicated malaria infection were screened for eligibility to participate in the study. Malaria infection was screened using microscopy. Children with uncomplicated P. falciparum monoinfection and who fulfilled all other inclusion criteria, and had none of the exclusion criteria, according to the World Health Organization (WHO) guidelines, were treated with ASAQ. Follow-up visits were scheduled on days 0, 1, 2, 3, 7, 14, 21, and 28 or on any day of recurrent infection for clinical and laboratory assessment. Polymerase chain reaction (PCR)-corrected cure rate on day 28 was the primary outcome. Results A total of 264 children, 88 in each of the three study sites (Mlimba, Mkuzi and Nagaga health facilities) were enrolled and treated with ASAQ. The ASAQ PCR-corrected cure rate was 100% at all the three study sites. None of the participants had early treatment failure or late clinical failure. Furthermore, none of the participants had a serious adverse event. Conclusion ASAQ was highly efficacious for the treatment of uncomplicated P. falciparum malaria in mainland Tanzania, therefore, it can be deployed as an alternative first-line treatment for uncomplicated malaria as part of diversification strategy to contain the spread of partial artemisinin resistance in the country.
Læs mere Tjek på PubMedMalaria Journal, 28.03.2024
Tilføjet 28.03.2024
Abstract A Stakeholder engagement meeting on the implementation of post-discharge malaria chemoprevention (PDMC) in Benin, Kenya, Malawi, and Uganda was held in Nairobi, Kenya, on 27 September 2023. Representatives from the respective National Malaria Control Programmes, the World Health Organization (WHO) Geneva, Africa Regional and Kenya offices, research partners, non-governmental organizations, and the Medicines for Malaria Venture participated. PDMC was recommended by the WHO in June 2022 and involves provision of a full anti-malarial treatment course at regular intervals during the post-discharge period in children hospitalized with severe anaemia in areas of moderate-to-high malaria transmission. The WHO recommendation followed evidence from a meta-analysis of three clinical trials and from acceptability, delivery, cost-effectiveness, and modelling studies. The trials were conducted in The Gambia using monthly sulfadoxine-pyrimethamine during the transmission season, in Malawi using monthly artemether-lumefantrine, and in Kenya and Uganda using monthly dihydroartemisinin-piperaquine, showing a significant reduction in all-cause mortality by 77% (95% CI 30–98) and a 55% (95% CI 44–64) reduction in all-cause hospital readmissions 6 months post-discharge. The recommendation has not yet been implemented in sub-Saharan Africa. There is no established platform for PDMC delivery. The objectives of the meeting were for the participating countries to share country contexts, plans and experiences regarding the adoption and implementation of PDMC and to explore potential delivery platforms in each setting. The meeting served as the beginning of stakeholder engagement within the PDMC Saves Lives project and will be followed by formative and implementation research to evaluate alternative delivery strategies in selected countries. Meeting highlights included country consensus on use of dihydroartemisinin-piperaquine for PDMC and expansion of the target group to "severe anaemia or severe malaria", in addition to identifying country-specific options for PDMC delivery for evaluation in implementation research. Further exploration is needed on whether the age group should be extended to school-age children.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 28.03.2024
Tilføjet 28.03.2024
Abstract Background GWAS have identified several non-functional tagSNPs associated with severe malaria. We hypothesized that causal SNPs could play a significant role in severe malaria by altering promoter or enhancer activity. Here, we sought to identify such regulatory SNPs.Methods SNPs in linkage disequilibrium with tagSNPs associated with severe malaria were identified and were further annotated using FUMA. Then, SNPs were prioritized using IW-scoring method to identify regulatory ones. Gene reporter assays were performed to assess the regulatory effect of a region containing candidates. The association between SNPs and severe malaria was assessed using logistic regression models in a Senegalese cohort.Results Among 418 SNPs, the best candidates were rs116525449 and rs79644959, which were in full disequilibrium between them, and located within the ARL14 promoter. Our gene reporter assay results revealed that the region containing the SNPs exhibited cell-specific promoter or enhancer activity, while the SNPs influenced promoter activity. We detected an association between severe malaria and those two SNPs using the overdominance model and we replicated the association of severe malaria with the tagSNP rs116423146.Conclusions We suggest that these SNPs regulate ARL14 expression in immune cells and the presentation of antigens to T lymphocytes, thus influencing severe malaria development.
Læs mere Tjek på PubMedMalaria Journal, 27.03.2024
Tilføjet 27.03.2024
Abstract Background The Magude Project assessed the feasibility of eliminating malaria in Magude district, a low transmission setting in southern Mozambique, using a package of interventions, including long-lasting insecticidal nets (LLINs). As the efficacy of LLINs depends in part on their physical integrity, this metric was quantified for Olyset® Nets post mass-distribution, in addition to net use, care and handling practices and other risk factors associated with net physical integrity. Methods Nets were collected during a cross-sectional net evaluation, nine months after the Magude project commenced, which was 2 years after the nets were distributed by the National Malaria Control Programme (NMCP). The physical integrity of the nets was assessed by counting and sizing the holes at different positions on each net. A structured questionnaire was administered to assess how the selected net was used and treated (care, wash and repair). Net bio-efficacy was assessed following the standard World Health Organization (WHO) cone bioassay procedures. Results Out of the 170 Olyset® Nets included in the analysis, 63.5% had been used the night before. The main reason for not using a net was the notion that there were no mosquitoes present. The average number of people using each net was 1.79. Two thirds of the nets had only been washed once or twice since distribution. Most nets (80.9%) were holed and 18% were torn, but none of the risk factors were significantly associated with net integrity, except for presence of mice in the household. Less than half of the participants noticed holes in holed nets, and of those only 38.6% attempted to repair those. None of the six nets that were tested for bio-efficacy passed the WHO threshold of 80% mosquito mortality. Conclusion Overall the majority of Olyset® Nets were in serviceable condition two years post-distribution, but their insecticidal effect may have been lost. This study—together with previous evidence on suboptimal access to and use of LLINs in Magude district—highlights that LLINs as an intervention could have been optimized during the Magude project to achieve maximum intervention impact.
Læs mere Tjek på PubMedMalaria Journal, 27.03.2024
Tilføjet 27.03.2024
Abstract Background Anopheles vagus (subgenus Cellia) has been identified as a vector for malaria, filariasis, and Japanese encephalitis in Asia. Sporozoites of Plasmodium falciparum and Plasmodium vivax have been found in this zoophilic mosquito in Asia and Indonesia. This study systematically reviews publications regarding An. vagus species, variation, bio-ecology, and malaria transmission in various localities in Asia, especially Indonesia, to determine whether the current data support An. vagus as a species complex. Methods The databases Pubmed, Scopus, Europe PMC, and Proquest were searched to identify information regarding the morphology, karyotypes, polytene chromosome, cross-mating, ecology, and molecular identification of An. vagus was then evaluated to determine whether there were possible species complexes. Results Of the 1326 articles identified, 15 studies were considered for synthesis. The Anopheles spp. samples for this study came from Asia. Eleven studies used morphology to identify An. vagus, with singular studies using each of karyotype identification, chromosomal polytene identification, and cross-breeding experiments. Ten studies used molecular techniques to identify Anopheles spp., including An. vagus. Most studies discovered morphological variations of An. vagus either in the same or different areas and ecological settings. In this review, the members of An. vagus sensu lato grouped based on morphology (An. vagus, An. vagus vagus, An. vagus limosus, and An. limosus), karyotyping (form A and B), and molecular (An. vagus genotype A and B, An. vagus AN4 and AN5). Genetic analysis revealed a high conservation of the ITS2 fragment among members except for the An. vagus genotype B, which was, in fact, Anopheles sundaicus. This review also identified that An. vagus limosus and An. vagus vagus were nearly identical to the ITS2 sequence. Conclusion Literature review studies revealed that An. vagus is conspecific despite the distinct morphological characteristic of An. vagus and An. limosus. Further information using another barcoding tool, such as mitochondrial COI and ND6 and experimental cross-mating between the An. vagus and An. limosus may provide additional evidence for the status of An. vagus as a species complex.
Læs mere Tjek på PubMedJebiwott, S., Gutapaka, N., Sumari, D., Loss, G., Athuman, T., Nyandele, J. P., Cummins, H., Chemba, M., Benjamin-Chung, J., Gangar, P., Wu, X., Smith, J., Chen, I., Dorsey, G., Fink, G., Olotu, A., Hsiang, M.
BMJ Open, 27.03.2024
Tilføjet 27.03.2024
IntroductionAs malaria declines, low-density malaria infections (LMIs) represent an increasing proportion of infections and may have negative impacts on child health and cognition, necessitating development of targeted and effective solutions. This trial assesses the health, cognitive and socioeconomic impact of two strategies for detecting and treating LMI in a low transmission setting. Methods and analysisThe study is a 3-arm open-label individually randomised controlled trial enrolling 600 children aged 6 months to 10 years in Bagamoyo district, Tanzania. Children are randomised to one of three arms: active case detection with molecular (ACDm) testing by high volume quantitative PCR (qPCR), passive case detection also with molecular testing (PCDm) and a control of standard PCD using rapid diagnostics tests (RDTs). Over the 2-year trial, ACDm participants receive malaria testing using RDT and qPCR three times annually, and malaria testing by RDT only when presenting with fever. PCDm and PCD participants receive malaria testing by RDT and qPCR or RDT only, respectively, when presenting with fever. RDT or qPCR positive participants with uncomplicated malaria are treated with artemether lumefantrine. The primary outcome is cumulative incidence of all-cause sick visits. Secondary outcomes include fever episodes, clinical failure after fever episodes, adverse events, malaria, non-malarial infection, antibiotic use, anaemia, growth faltering, cognition and attention, school outcomes, immune responses, and socioeconomic effects. Outcomes are assessed through monthly clinical assessments and testing, and baseline and endline neurodevelopmental testing. The trial is expected to provide key evidence and inform policy on health, cognitive and socioeconomic impact of interventions targeting LMI in children. Ethics and disseminationStudy is approved by Tanzania NatHREC and institutional review boards at University of California San Francisco and Ifakara Health Institute. Findings will be reported on ClinicalTrials.gov, in peer-reviewed journals and through stakeholder meetings. Trial registration number NCT05567016.
Læs mere Tjek på PubMedMalaria Journal, 27.03.2024
Tilføjet 27.03.2024
Abstract Background The degree to which Anopheles mosquitoes prefer biting humans over other vertebrate hosts, i.e. the human blood index (HBI), is a crucial parameter for assessing malaria transmission risk. However, existing techniques for identifying mosquito blood meals are demanding in terms of time and effort, involve costly reagents, and are prone to inaccuracies due to factors such as cross-reactivity with other antigens or partially digested blood meals in the mosquito gut. This study demonstrates the first field application of mid-infrared spectroscopy and machine learning (MIRS-ML), to rapidly assess the blood-feeding histories of malaria vectors, with direct comparison to PCR assays. Methods and results Female Anopheles funestus mosquitoes (N = 1854) were collected from rural Tanzania and desiccated then scanned with an attenuated total reflectance Fourier-transform Infrared (ATR-FTIR) spectrometer. Blood meals were confirmed by PCR, establishing the ‘ground truth’ for machine learning algorithms. Logistic regression and multi-layer perceptron classifiers were employed to identify blood meal sources, achieving accuracies of 88%–90%, respectively, as well as HBI estimates aligning well with the PCR-based standard HBI. Conclusions This research provides evidence of MIRS-ML effectiveness in classifying blood meals in wild Anopheles funestus, as a potential complementary surveillance tool in settings where conventional molecular techniques are impractical. The cost-effectiveness, simplicity, and scalability of MIRS-ML, along with its generalizability, outweigh minor gaps in HBI estimation. Since this approach has already been demonstrated for measuring other entomological and parasitological indicators of malaria, the validation in this study broadens its range of use cases, positioning it as an integrated system for estimating pathogen transmission risk and evaluating the impact of interventions.
Læs mere Tjek på PubMedMalaria Journal, 22.03.2024
Tilføjet 22.03.2024
Abstract Background The burden of Malaria in Zambia remains a challenge, with the entire population at risk of contracting this infectious disease. Despite concerted efforts by African countries, including Zambia, to implement malaria policies and strategies aimed at reducing case incidence, the region faces significant hurdles, especially with emerging pandemics such as COVID-19. The efforts to control malaria were impacted by the constraints imposed to curb its transmission during the COVID-19 pandemic. The aim of the study was to assess the effect of the COVID-19 pandemic on malaria cases in Zambia and the factors associated by comparing the COVID-19 period and the pre-COVID-19 era. Methods This was a cross-sectional panel study in which routinely collected programmatic data on malaria was used. The data were extracted from the Health Management Information System (HMIS) for the period January 2018 to January 2022. The period 2018 to 2022 was selected purely due to the availability of data and to avoid the problem of extrapolating too far away from the period of interest of the study. A summary of descriptive statistics was performed in which the number of cases were stratified by province, age group, and malaria cases. The association of these variables with the COVID-19 era was checked using the Wilcoxon rank-sum test and Kruskal‒Wallis test as applicable. In establishing the factors associated with the number of malaria cases, a mixed-effect multilevel model using the Poisson random intercept and random slope of the COVID-19 panel. The model was employed to deal with the possible correlation of the number of cases in the non-COVID-19 panel and the expected correlation of the number of cases in the COVID-19 panel. Results A total of 18,216 records were extracted from HMIS from January 2018 to January 2022. Stratifying this by the COVID-19 period/era, it was established that 8,852 malaria cases were recorded in the non-COVID-19 period, whereas 9,364 cases were recorded in the COVID-19 era. Most of the people with malaria were above the age of 15 years. Furthermore, the study found a significant increase in the relative incidence of the COVID-19 panel period compared to the non-COVID-19 panel period of 1.32, 95% CI (1.18, 1.48, p
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