Nyt fra tidsskrifterne
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102932
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102890
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102891
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102892
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102893
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102894
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102895
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102896
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102897
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102860
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102816
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102814
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102802
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102758
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102742
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102736
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102721
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102690
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102691
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102652
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102653
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102654
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102656
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102578
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102579
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102580
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102530
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102492
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102493
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102484
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102485
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102460
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102461
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102462
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102429
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102405
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102406
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102407
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102408
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102387
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102348
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102282
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102245
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102215
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102175
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102163
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102164
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102156
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102110
Klik på knappen for at kopiere eller tryk på linket nedenfor.
Kopieret til udklipsholder!
https://infmed.dk/nyheder-udefra?rss_filter=malaria&setpoint=99211#102080
Søgeord (malaria) valgt.
196 emner vises.
Garrett, Nigel; Dintwe, One; Monaco, Cynthia L.; Jones, Megan; Seaton, Kelly E.; Church, E. Chandler; Grunenberg, Nicole; Hutter, Julia; deCamp, Allan; Huang, Yunda; Lu, Huiyin; Mann, Philipp; Robinson, Samuel T.; Heptinstall, Jack; Jensen, Ryan L.; Pantaleo, Giuseppe; Ding, Song; Koutsoukos, Marguerite; Hosseinipour, Mina C.; Van Der Meeren, Olivier; Gilbert, Peter B.; Ferrari, Guido; Andersen-Nissen, Erica; McElrath, M. Juliana; Tomaras, Georgia D.; Gray, Glenda E.; Corey, Lawrence; Kublin, James G.; on behalf of the HVTN 108 and HVTN 111 Study Teams
Journal of Acquired Immune Deficiency Syndromes, 9.05.2024
Tilføjet 9.05.2024
Despite progress in HIV prevention and treatment, an estimated 1.3 million people were newly infected with HIV in 2022,1 highlighting the urgent need for an effective vaccine. To date, the RV144 trial remains the only HIV vaccine trial that has demonstrated partial efficacy against acquisition.2 The Pox-Protein Public-Private Partnership (P5) was established with the aims of improving on RV144 by developing a vaccine capable of protecting against a broader diversity of HIV strains and achieving a better understanding of immune responses associated with preventing HIV infection.3 Vaccine concepts in the P5 program have focused on clade C immunogens, targeting predominant strains of East and Southern Africa, where approximately half of the 39 million people living with HIV reside.1 Despite progress in HIV prevention and treatment, an estimated 1.3 million people were newly infected with HIV in 2022,1 highlighting the urgent need for an effective vaccine. To date, the RV144 trial remains the only HIV vaccine trial that has demonstrated partial efficacy against acquisition.2 The Pox-Protein Public-Private Partnership (P5) was established with the aims of improving on RV144 by developing a vaccine capable of protecting against a broader diversity of HIV strains and achieving a better understanding of immune responses associated with preventing HIV infection.3 Vaccine concepts in the P5 program have focused on clade C immunogens, targeting predominant strains of East and Southern Africa, where approximately half of the 39 million people living with HIV reside.1 The RV144 regimen, originally designed to protect against subtype B/E strains, was adapted to incorporate clade C antigens and adjuvanted with MF59®.4 This regimen demonstrated adequate immunogenicity in the HVTN100 phase 1/2a trial,5 and was further evaluated in the HVTN702 efficacy trial in South Africa, but ultimately discontinued due to non-efficacy.6 In parallel, the P5 designed the correlates program: a series of phase 1/2a trials to evaluate vaccine candidates based on favorable immune profiles of putative correlates of protection. These trials employed novel prime-boost and co-administration regimens, varied protein doses, and used new adjuvants and vaccine delivery systems, with an emphasis on shared immunological endpoints to allow for cross-study comparisons. Preclinical studies have shown promising immune responses using DNA/protein combination vaccines.7,8 A comparison of responses between HVTN100 (ALVAC) and HVTN111 (DNA) trials indicated that DNA priming with a protein boost led to increased antibody and cellular responses compared to priming with the canarypox vector.9 In the HVTN105 trial, both a DNA prime-protein boost and a co-administration regimen induced potent and durable V1/V2 binding antibody responses (a known correlate of lower HIV-1 infection risk in RV144), with co-administration inducing early antibody responses.10 Furthermore, in the HVTN096 trial, including gp120 Env protein at the priming stage, co-administered with either NYVAC or DNA, elicited earlier and even greater antibody responses.11 The adjuvant system 01 (AS01) has been successfully tested in vaccine trials for other infectious diseases including malaria,12 shingles,13,14 and tuberculosis.15 Some HIV vaccine studies have also used AS01 and have shown that it contributes to the induction of robust and persistent cellular and humoral responses.16,17 MF59® has likewise been used in several licensed vaccines and pre-clinical studies,18 inducing strong and durable T-cell memory and humoral responses. MF59® was also used in HVTN studies with ALVAC 5 and was therefore chosen for comparison with AS01B in this trial. Thus, the aim of the HVTN108 trial was to evaluate the safety and immunogenicity of the DNA vaccine with different HIV clade C protein doses, adjuvanted with MF59® or AS01B, and dosed in prime-boost or co-administration regimens. Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background Artemisinin resistance in Plasmodium falciparum threatens global malaria elimination efforts. To contain and then eliminate artemisinin resistance in Eastern Myanmar a network of community-based malaria posts was instituted and targeted mass drug administration (MDA) with dihydroartemisinin-piperaquine (three rounds at monthly intervals) was conducted. The prevalence of artemisinin resistance during the elimination campaign (2013–2019) was characterized. Methods Throughout the six-year campaign Plasmodium falciparum positive blood samples from symptomatic patients and from cross-sectional surveys were genotyped for mutations in kelch-13—a molecular marker of artemisinin resistance. Result The program resulted in near elimination of falciparum malaria. Of 5162 P. falciparum positive blood samples genotyped, 3281 (63.6%) had K13 mutations. The prevalence of K13 mutations was 73.9% in 2013 and 64.4% in 2019. Overall, there was a small but significant decline in the proportion of K13 mutants (p
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background Universal coverage with insecticide-treated nets (ITNs) is important for malaria control and elimination. The emergence and intensification of insecticide resistance threatens progress made through the deployment of these interventions and has required the development of newer, more expensive ITN types. Understanding malaria prevention behaviour, including barriers and facilitators to net access and use, can support effective decision-making for the promotion and distribution of ITNs. Methods In-depth interviews and focus group discussions were conducted in 3 to 4 villages per district, in 13 districts across Burkina Faso, Mozambique, Nigeria and Rwanda from 2019 to 2022. Interviews were conducted in the local language, translated and transcribed in English, French or Portuguese. Transcripts were coded and analysed using Nvivo and ATLAS.ti. Results ITNs were obtained from mass distribution campaigns, antenatal care and immunization visits, and purchased on the private market in some locations. While there were divergent perspectives in whether the number of distributed nets were adequate, participants consistently expressed concerns of bias, discrimination, and a lack of transparency with the distribution process. ITNs were frequently used alongside other malaria prevention methods. The primary motivation for use was malaria prevention. While some participants reported using nets nightly throughout the year, other participants reported seasonal use, both due to the perceived higher density of mosquitoes and discomfort of sleeping under a net in the increased heat. Other barriers to consistent net use included activities that take place away from the home, sleeping patterns and arrangements, and sensitivity to the insecticides on the nets. Conclusions ITNs remain an important malaria control intervention. To ensure adequate and increased net access, distribution campaigns should consider family structures, available sleeping spaces, and other bed sharing preferences when identifying the number of nets needed for distribution. In addition, campaigns should allow for multiple options for net distribution points and timing to accommodate households remote to health services. Continuous distribution channels and complimentary distribution through the private sector could help fill gaps in coverage. Solutions are needed for outdoor malaria transmission, including alternative designs for ITNs, and improving access to complementary personal protective measures.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background The direct membrane feeding assay (DMFA), whereby gametocyte-infected blood is collected from human donors and from which mosquitoes feed through a membrane, is proving essential for assessing parameters influencing Plasmodium transmission potential in endemic countries. The success of DMFAs is closely tied to gametocyte density in the blood, with relatively high gametocytaemia ensuring optimal infection levels in mosquitoes. As transmission intensity declines with control efforts, the occurrence of asymptomatic individuals with low gametocyte densities, who can significantly contribute to the infectious reservoir, is increasing. This poses a limitation to studies relying on the experimental infection of large numbers of mosquitoes with natural isolates of Plasmodium. A simple, field-applicable method is presented for improving parasite infectivity by concentrating Plasmodium falciparum gametocytes. Methods Anopheles gambiae received one of the following 5 blood treatments through DMFA: (i) whole blood (WB) samples from naturally-infected donors; (ii) donor blood whose plasma was replaced with the same volume of Plasmodium-naive AB + serum (1:1 control); (iii) plasma replaced with a volume of malaria-naïve AB + serum equivalent to half (1:1/2), or to a quarter (1:1/4), of the initial plasma volume; and (v) donor blood whose plasma was fully removed (RBC). The experiment was repeated 4 times using 4 distinct wild parasite isolates. Seven days post-infection, a total of 1,095 midguts were examined for oocyst presence. Results Substituting plasma with reduced amounts (1:1/2 and 1:1/4) of Plasmodium-naive AB + serum led to a 31% and 17% increase of the mosquito infection rate and to a 85% and 308% increase in infection intensity compared to the 1:1 control, respectively. The full removal of plasma (RBC) reduced the infection rate by 58% and the intensity by 64% compared to the 1:1 control. Reducing serum volumes (1:1/2; 1:1/4 and RBC) had no impact on mosquito feeding rate and survival when compared to the 1:1 control. Conclusions Concentrating gametocytic blood by replacing natural plasma by lower amount of naive serum can enhance the success of mosquito infection. In an area with low gametocyte density, this simple and practical method of parasite concentration can facilitate studies on human-to-mosquito transmission such as the evaluation of transmission-blocking interventions.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Malaria vaccine introduction in endemic countries is a game-changing milestone in the fight against the disease. This article examines the inequity in the global pharmaceutical research, development, manufacturing, and trade landscape. The role of inequity in hindering progress towards malaria elimination is explored. The analysis finds that transformational changes are required to create an equity-enabling environment. Addressing the inequity is critical to maximizing the public health impact of vaccines and attaining sustainability. Avenues to catalyze progress by leveraging malaria vaccines and messenger ribonucleic acid (mRNA) technology are discussed.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background Studies on haemosporidian diversity, including origin of human malaria parasites, malaria\'s zoonotic dynamic, and regional biodiversity patterns, have used target gene approaches. However, current methods have a trade-off between scalability and data quality. Here, a long-read Next-Generation Sequencing protocol using PacBio HiFi is presented. The data processing is supported by a pipeline that uses machine-learning for analysing the reads. Methods A set of primers was designed to target approximately 6 kb, almost the entire length of the haemosporidian mitochondrial genome. Amplicons from different samples were multiplexed in an SMRTbell® library preparation. A pipeline (HmtG-PacBio Pipeline) to process the reads is also provided; it integrates multiple sequence alignments, a machine-learning algorithm that uses modified variational autoencoders, and a clustering method to identify the mitochondrial haplotypes/species in a sample. Although 192 specimens could be studied simultaneously, a pilot experiment with 15 specimens is presented, including in silico experiments where multiple data combinations were tested. Results The primers amplified various haemosporidian parasite genomes and yielded high-quality mt genome sequences. This new protocol allowed the detection and characterization of mixed infections and co-infections in the samples. The machine-learning approach converged into reproducible haplotypes with a low error rate, averaging 0.2% per read (minimum of 0.03% and maximum of 0.46%). The minimum recommended coverage per haplotype is 30X based on the detected error rates. The pipeline facilitates inspecting the data, including a local blast against a file of provided mitochondrial sequences that the researcher can customize. Conclusions This is not a diagnostic approach but a high-throughput method to study haemosporidian sequence assemblages and perform genotyping by targeting the mitochondrial genome. Accordingly, the methodology allowed for examining specimens with multiple infections and co-infections of different haemosporidian parasites. The pipeline enables data quality assessment and comparison of the haplotypes obtained to those from previous studies. Although a single locus approach, whole mitochondrial data provide high-quality information to characterize species pools of haemosporidian parasites.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background Malaria is a potentially life-threatening disease caused by Plasmodium protozoa transmitted by infected Anopheles mosquitoes. Controlled human malaria infection (CHMI) trials are used to assess the efficacy of interventions for malaria elimination. The operating characteristics of statistical methods for assessing the ability of interventions to protect individuals from malaria is uncertain in small CHMI studies. This paper presents simulation studies comparing the performance of a variety of statistical methods for assessing efficacy of intervention in CHMI trials. Methods Two types of CHMI designs were investigated: the commonly used single high-dose design (SHD) and the repeated low-dose design (RLD), motivated by simian immunodeficiency virus (SIV) challenge studies. In the context of SHD, the primary efficacy endpoint is typically time to infection. Using a continuous time survival model, five statistical tests for assessing the extent to which an intervention confers partial or full protection under single dose CHMI designs were evaluated. For RLD, the primary efficacy endpoint is typically the binary infection status after a specific number of challenges. A discrete time survival model was used to study the characteristics of RLD versus SHD challenge studies. Results In a SHD study with the continuous time survival model, log-rank test and t-test are the most powerful and provide more interpretable results than Wilcoxon rank-sum tests and Lachenbruch tests, while the likelihood ratio test is uniformly most powerful but requires knowledge of the underlying probability model. In the discrete time survival model setting, SHDs are more powerful for assessing the efficacy of an intervention to prevent infection than RLDs. However, additional information can be inferred from RLD challenge designs, particularly using a likelihood ratio test. Conclusions Different statistical methods can be used to analyze controlled human malaria infection (CHMI) experiments, and the choice of method depends on the specific characteristics of the experiment, such as the sample size allocation between the control and intervention groups, and the nature of the intervention. The simulation results provide guidance for the trade off in statistical power when choosing between different statistical methods and study designs.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background In Nigeria, seasonal malaria chemoprevention (SMC) is typically administered door-to-door to children under five by community medicine distributors during high transmission seasons. While door-to-door distribution (DDD) is exclusively employed in Nigeria as part of standard operating procedures of SMC programmes, some households access SMC through non-DDD channels, such as fixed-point distributions, health facilities, and private purchase. However, analysis of access to SMC medicines through non-DDD has been limited, with little evidence of its outcomes on adherence to the three-day complete course of SMC medicines and caregiver actions in the event of adverse reactions to SMC medicines. Methods Data were obtained from SMC end-of-round coverage surveys conducted in Nigeria in 2021 and 2022, including 25,278 households for the analysis. The proportion of households accessing SMC medicine through non-DDD and the distribution of various non-DDD sources of SMC medicines were described. Multivariate random-effects logistic regression models were performed to identify predictors of accessing SMC medicines through non-DDD. The associations between non-DDD, and caregiver-reporting of adherence to complete administration of SMC medicines and caregiver actions in the event of adverse reactions to SMC medicines were also assessed. Results Less than 2% (314/24003) of households accessed SMC medicines through non-DDD in the states surveyed. Over 60% of non-DDD access was via health facility personnel and community medicine distributors from different locations. Variables associated with non-DDD access included heads of household being born in the local state (OR = 0.68, 95% CI 0.47 to 0.90), households residing in the study state since the first cycle of the SMC round (OR = 0.39, 95% CI 0.17 to 0.88), households with high wealth index (OR = 1.36, 95% CI 1.01 to 1.82), and caregivers hearing about date of SMC delivery in the previous cycle (OR = 0.18, 95%CI 0.14 to 0.24). Furthermore, non-DDD was associated with reduced SMC adherence and higher caregiver non-reporting of adverse reactions to SMC medicines in children compared with DDD. Conclusion This study provides evidence on the characteristics of households accessing SMC medicines through non-DDD and its potential negative outcomes on adherence to SMC medicine and adverse reaction reporting, underscoring potential implementation issues that may arise if non-DDD delivery models are adopted in SMC, particularly in places where DDD had been firstly used.
Læs mere Tjek på PubMedMalaria Journal, 8.05.2024
Tilføjet 8.05.2024
Abstract Background Drug repurposing offers a strategic alternative to the development of novel compounds, leveraging the known safety and pharmacokinetic profiles of medications, such as linezolid and levofloxacin for tuberculosis (TB). Anti-malarial drugs, including quinolones and artemisinins, are already applied to other diseases and infections and could be promising for TB treatment. Methods This review included studies on the activity of anti-malarial drugs, specifically quinolones and artemisinins, against Mycobacterium tuberculosis complex (MTC), summarizing results from in vitro, in vivo (animal models) studies, and clinical trials. Studies on drugs not primarily developed for TB (doxycycline, sulfonamides) and any novel developed compounds were excluded. Analysis focused on in vitro activity (minimal inhibitory concentrations), synergistic effects, pre-clinical activity, and clinical trials. Results Nineteen studies, including one ongoing Phase 1 clinical trial, were analysed: primarily investigating quinolones like mefloquine and chloroquine, and, to a lesser extent, artemisinins. In vitro findings revealed high MIC values for anti-malarials versus standard TB drugs, suggesting a limited activity. Synergistic effects with anti-TB drugs were modest, with some synergy observed in combinations with isoniazid or pyrazinamide. In vivo animal studies showed limited activity of anti-malarials against MTC, except for one study of the combination of chloroquine with isoniazid. Conclusions The repurposing of anti-malarials for TB treatment is limited by high MIC values, poor synergy, and minimal in vivo effects. Concerns about potential toxicity at effective dosages and the risk of antimicrobial resistance, especially where TB and malaria overlap, further question their repurposing. These findings suggest that focusing on novel compounds might be both more beneficial and rewarding.
Læs mere Tjek på PubMedEnoch Aninagyei, John Gameli Deku, Keren Trishia Yemofio, Ekua Quainoo, Kofi Adjei Ntiri, Evelyn Yaro, Priscilla Essandoh, Hubert Kwame Agbogli, Richard Harry Asmah
PLoS One Infectious Diseases, 8.05.2024
Tilføjet 8.05.2024
by Enoch Aninagyei, John Gameli Deku, Keren Trishia Yemofio, Ekua Quainoo, Kofi Adjei Ntiri, Evelyn Yaro, Priscilla Essandoh, Hubert Kwame Agbogli, Richard Harry Asmah Malaria rapid diagnostic test (mRDT) kit is one of the techniques for diagnosing malaria. Due to its inherent advantages over the microscopy technique, several brands of the kit have flooded malaria endemic countries, without prior in-country evaluation. Two of such mRDT kits are Oscar (India) and Standard Q (Korea Republic). In this study, the performance of Oscar and Standard Q mRDT kits were compared to First Response (India) and CareStart (USA) mRDTs, which have been evaluated and deployed for use approved by the Ministry of Health (MOH). In this comparative study, whole blood samples were collected from patients suspected of malaria. Plasmodium falciparum was detected in each sample using nested polymerase chain reaction (nPCR), microscopy and the four mRDTs. The sensitivities, specificities, accuracies, positive and negative predictive values and accuracies of the mRDTs were determined using nPCR as a reference technique. Kappa statistic was used to determine the level of agreement among the techniques. Two hundred (200) blood samples were analyzed in this study. The overall detection rates of P. falciparum by microscopy, First Response, CareStart, Oscar-PfHRP2, Standard Q mRDT kits and nPCR were 31.5%, 34.5%, 33.5%, 32%, 31% and 43% (x2 = 6.1, p = 0.046), respectively. The accuracies of CareStart and First Response were comparable (90.5% vs. 89.5%). Further, comparing their sensitivities, Oscar-PfHRP2 was 74.4% (95% confidence interval (CI): 63.9–83.2) while that of Standard Q was 72.1% (95% CI: 61.4–81.2), with comparable accuracies (Oscar-PfHRP2–89% and Standard Q -88%). Apart from First Response that was 98.3% specific, the others were 100% specific. Kappa test revealed perfect diagnostic agreement (κ = 0.90–0.98) among the four mRDTs. That notwithstanding, Oscar-PfHRP2 agreed better with CareStart (κ = 0.94) and First Response (κ = 0.92) compared to the agreement between Standard Q and, CareStart (κ = 0.92) and First Response (κ = 0.90). Taken together, the diagnostic performance of the four mRDT kits were statistically similar. That notwithstanding, new mRDT kits should be evaluated prior to deployment for use.
Læs mere Tjek på PubMedCamila Marques-da-Silva, Clyde Schmidt-Silva, Samarchith P. Kurup
Trends in Parasitology, 7.05.2024
Tilføjet 7.05.2024
The Plasmodium parasites that cause malaria undergo asymptomatic development in the parenchymal cells of the liver, the hepatocytes, prior to infecting erythrocytes and causing clinical disease. Traditionally, hepatocytes have been perceived as passive bystanders that allow hepatotropic pathogens such as Plasmodium to develop relatively unchallenged. However, now there is emerging evidence suggesting that hepatocytes can mount robust cell-autonomous immune responses that target Plasmodium, limiting its progression to the blood and reducing the incidence and severity of clinical malaria. Here we discuss our current understanding of hepatocyte cell-intrinsic immune responses that target Plasmodium and how these pathways impact malaria.
Læs mere Tjek på PubMedMichal Juraska, Angela M Early, Li Li, Stephen F Schaffner, Marc Lievens, Akanksha Khorgade, Brian Simpkins, Nima S Hejazi, David Benkeser, Qi Wang, Laina D Mercer, Samuel Adjei, Tsiri Agbenyega, Scott Anderson, Daniel Ansong, Dennis K Bii, Patrick B Y Buabeng, Sean English, Nicholas Fitzgerald, Jonna Grimsby, Simon K Kariuki, Kephas Otieno, François Roman, Aaron M Samuels, Nelli Westercamp, Christian F Ockenhouse, Opokua Ofori-Anyinam, Cynthia K Lee, Bronwyn L MacInnis, Dyann F Wirth, Peter B Gilbert, Daniel E Neafsey
Lancet Infectious Diseases, 7.05.2024
Tilføjet 7.05.2024
All tested dosing regimens blocked some infections to a similar degree. Improved vaccine efficacy in participants infected during vaccination could suggest new strategies for highly efficacious malaria vaccine development and implementation.
Læs mere Tjek på PubMedReina Engle-Stone, K Ryan Wessells, Marjorie J. Haskell, Sika M. Kumordzie, Charles D. Arnold, Jennie N. Davis, Emily R. Becher, Ahmed D. Fuseini, Kania W. Nyaaba, Xiuping Tan, Katherine P. Adams, Georg Lietz, Stephen A. Vosti, Seth Adu-Afarwuah
PLoS One Infectious Diseases, 6.05.2024
Tilføjet 6.05.2024
by Reina Engle-Stone, K Ryan Wessells, Marjorie J. Haskell, Sika M. Kumordzie, Charles D. Arnold, Jennie N. Davis, Emily R. Becher, Ahmed D. Fuseini, Kania W. Nyaaba, Xiuping Tan, Katherine P. Adams, Georg Lietz, Stephen A. Vosti, Seth Adu-Afarwuah Introduction Micronutrient deficiencies are prevalent in West Africa, particularly among women of reproductive age (WRA) and young children. Bouillon is a promising food fortification vehicle due to its widespread consumption. This study aims to evaluate the impact of multiple micronutrient-fortified bouillon cubes, compared to control bouillon cubes (fortified with iodine only), on micronutrient status and hemoglobin concentrations among lactating and non-lactating WRA and young children in northern Ghana. Methods This randomized, controlled doubly-masked trial will be conducted in the Kumbungu and Tolon districts in the Northern Region of Ghana, where prior data indicate multiple micronutrient deficiencies are common. Participants will be: 1) non-pregnant non-lactating WRA (15–49 y), 2) children 2–5 y, and 3) non-pregnant lactating women 4–18 months postpartum. Eligible participants will be randomly assigned to receive household rations of one of two types of bouillon cubes: 1) a multiple micronutrient-fortified bouillon cube containing vitamin A, folic acid, vitamin B12, iron, zinc, and iodine, or 2) a control cube containing iodine only.Each participant’s household will receive a ration of bouillon cubes every 2 weeks, and households will be advised to prepare meals as usual, using the study-provided cubes. The trial duration will be 9 months for non-pregnant non-lactating WRA and children, and 3 months for lactating women. The primary outcomes will be changes in biomarkers of micronutrient status and hemoglobin among WRA and children and milk micronutrient concentrations among lactating women. Secondary outcomes will include change in prevalence of micronutrient deficiency and anemia; dietary intake of bouillon and micronutrients; inflammation, malaria, and morbidity symptoms; and child growth and development. Discussion Evidence from this study will inform discussions about bouillon fortification in Ghana and West Africa. Trial registration The trial was registered on ClinicalTrials.gov (NCT05178407) and the Pan-African Clinical Trial Registry (PACTR202206868437931). This manuscript reflects protocol version 4 (August 29, 2022).
Læs mere Tjek på PubMedShirin TaheriMikel Alexander GonzálezMaría José Ruiz-LópezSergio MagallanesSarah Delacour-EstrellaJavier LucientesRubén Bueno-MaríJosué Martínez-de la PuenteDaniel Bravo-BarrigaEva FronteraAlejandro PolinaYasmina Martinez-BarcielaJosé Manuel PereiraJosefina GarridoCarles ArandaAlfonso MarzalIgnacio Ruiz-ArrondoJosé Antonio OteoMartina FerragutiRafael Gutíerrez-LópezRosa EstradaMiguel Ángel MirandaCarlos BarcelóRodrigo MorchónTomas MontalvoLaura GangosoFátima GoiriAna L. García-PérezSantiago RuizBeatriz Fernandez-MartinezDiana Gómez-BarrosoJordi Figuerolaa Departamento de Biología de la Conservación y Cambio Global, Estación Biológica de Doñana (EBD), CSIC, Sevilla, Spainb CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spainc The Agrifood Institute of Aragón (IA2), Faculty of Veterinary Medicine, University of Zaragoza, Zaragoza, Spaind Center of Excellence in Vector Control, Rentokil Initial, València, Spaine Grupo de Investigación Parásitos y Salud, Universitat de València, València, Spainf Departamento de Parasitología, Universidad de Granada, Granada, Spaing Departamento de Salud Animal, Grupo de Investigación en Salud Animal y Zoonosis (GISAZ), Facultad de Veterinaria, Universidad de Córdoba, Córdoba, Spainh Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de Extremadura (UEx), Cáceres, Spaini Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Pontevedra, Spainj Departamento de Zooloxía, Xenética e Antropoloxía Física, Universidade de Santiago de Compostela, A Coruña, Spaink Servei de Control de Mosquits del Baix Llobregat, Sant Feliu del Llobregat, Barcelona, Spainl IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus Universitat Autònoma de Barcelona, Bellaterra, Spainm Facultad de Biología, Universidad de Extremadura, Badajoz, Spainn Grupo de Investigaciones en Fauna Silvestre, Universidad Nacional de San Martín, Tarapoto, Perúo Centre of Rickettsiosis and Arthropod-Borne Diseases, Hospital Universitario San Pedro-CIBIR, La Rioja, Logroño, Spainp Centro Nacional de Microbiología (CNM-ISCIII), Madrid, Spainq CIBER de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spainr Universitat de les Illes Balears (UIB), Zoología Aplicada y de la Conservación, Palma, Spains Zoonotic Diseases and One Health Group, Faculty of Pharmacy, Universidad de Salamanca, Salamanca, Spaint Agencia de Salut Publica de Barcelona, Barcelona, Spainu Universidad Complutense de Madrid, Madrid, Spainv NEIKER-Instituto Vasco de Investigación y Desarrollo Agrario, Derio, Spainw Servicio de Control de Mosquitos de la Diputación de Huelva, Huelva, Spainx Centro Nacional de Epidemiologia (CNE-ISCIII), Madrid, Spain
Emerg Microbes Infect, 3.05.2024
Tilføjet 3.05.2024
Jane M. Carlton and Aubrey J. Cunnington
Science, 3.05.2024
Tilføjet 3.05.2024
Harun K. Aremu, Christianah A. Dare, Idris A. Adekale, Bukunmi D. Adetunji, Dickson A. Musa, Luqmon A. Azeez, Olu I. Oyewole
PLoS One Infectious Diseases, 3.05.2024
Tilføjet 3.05.2024
by Harun K. Aremu, Christianah A. Dare, Idris A. Adekale, Bukunmi D. Adetunji, Dickson A. Musa, Luqmon A. Azeez, Olu I. Oyewole The incorporation of phytoactive compounds in the management of malarial vectors holds promise for the development of innovative and efficient alternatives. Nevertheless, the molecular and physiological responses that these bioactive substances induce remain underexplored. This present study investigated the toxicity of different concentrations of aqueous and methanol extracts of Ocimum tenuiflorum against larvae of Anopheles gambiae (sensu stricto) and unraveled the possible underlying molecular pathways responsible for the observed physiological effects. FTIR and GCMS analyses of phytoactive compounds in aqueous and methanol crude extracts of O. tenuiflorum showed the presence of OH stretching vibration, C = C stretching modes of aromatics and methylene rocking vibration; ring deformation mode with high levels of trans-β-ocimene, 3,7-dimethyl-1,3,6-octatriene in aqueous extract and 4-methoxy-benzaldehyde, 1,3,5-trimethyl-cyclohexane and o-cymene in methanol extract. The percentage mortality upon exposure to methanol and aqueous extracts of O. tenuiflorum were 21.1% and 26.1% at 24 h, 27.8% and 36.1% at 48 h and 36.1% and 45% at 72 h respectively. Using reverse transcription quantitative polymerase chain reaction (RT-qPCR), down-regulation of ABC transporter, overexpression of CYP6M2, Hsp70, and α-esterase, coupled with significantly increased levels of SOD, CAT, and GSH, were observed in An. gambiae (s.s.) exposed to aqueous and methanol extracts of O. tenuiflorum as compared to the control. Findings from this study have significant implications for our understanding of how An. gambiae (s.s.) larvae detoxify phytoactive compounds.
Læs mere Tjek på PubMedOmale, U. I., Ogbonnaya, L. U., Iyare, O., Nnachi, O. O.
BMJ Open, 2.05.2024
Tilføjet 2.05.2024
ObjectivesThe burden of malaria has persistently been high in Ebonyi state and Nigeria despite long-standing collaborations with international partners with huge and increased amounts of financial investments. We explored the system-wide governance challenges of the Ebonyi State Malaria Elimination Programme (SMEP) and the factors responsible in order to make recommendations for malaria health system strengthening. DesignWe did a qualitative study informed by the health system governance framework by Mikkelsen-Lopez et al and Savedoff’s concept of governance. Setting and participantsBetween 18 October 2022 and 8 November 2022, 25 semistructured face-to-face in-depth interviews were conducted in English with purposively selected key stakeholders in the Ebonyi SMEP aged 18 years or older with at least 2 years of involvement in the SMEP and who gave consent. AnalysisData were analysed deductively and the analytical strategy was informed by the framework method for the analysis of qualitative data by Gale et al. ResultsMany system-wide governance challenges of the SMEP were identified including the absence of state’s strategic vision and plans for malaria elimination; very weak primary and secondary healthcare systems; inadequate financial allocation and untimely release of budgeted funds by the state government; lack of human resources for health and very poor mosquito net distribution system. Other challenges were inadequate stakeholders’ participation; poor accountability culture; impaired transparency and corruption and impaired ability to address corruption. The fundamental responsible factors were the lack of state government’s concern for people’s welfare and lack of interest and commitment to the malaria elimination effort, chronic non-employment of staff and lack of human resources in the entire health sector including SMEP, and nepotism and godfatherism. ConclusionsThe system-wide governance challenges and the responsible factors call for changing the ‘business as usual’ and refocusing on strengthening malaria health system governance in addressing the persisting malaria health problems in Ebonyi state (and Nigeria).
Læs mere Tjek på PubMedMalaria Journal, 2.05.2024
Tilføjet 2.05.2024
Abstract Background The sequestration of Plasmodium falciparum infected erythrocytes in the placenta, and the resulting inflammatory response affects maternal and child health. Despite existing information, little is known about the direct impact of P. falciparum on the placental barrier formed by trophoblast and villous stroma. This study aimed to assess placental tissue damage caused by P. falciparum in human placental explants (HPEs). Methods HPEs from chorionic villi obtained of human term placentas (n = 9) from normal pregnancies were exposed to P. falciparum-infected erythrocytes (IE) for 24 h. HPEs were embedded in paraffin blocks and used to study tissue damage through histopathological and histochemical analysis and apoptosis using TUNEL staining. Culture supernatants were collected to measure cytokine and angiogenic factors and to determine LDH activity as a marker of cytotoxicity. A subset of archived human term placenta paraffin-embedded blocks from pregnant women with malaria were used to confirm ex vivo findings. Results Plasmodium falciparum-IE significantly damages the trophoblast layer and the villous stroma of the chorionic villi. The increased LDH activity and pathological findings such as syncytial knots, fibrin deposits, infarction, trophoblast detachment, and collagen disorganization supported these findings. The specific damage to the trophoblast and the thickening of the subjacent basal lamina were more pronounced in the ex vivo infection. In contrast, apoptosis was higher in the in vivo infection. This disparity could be attributed to the duration of exposure to the infection, which significantly varied between individuals naturally exposed over time and the 24-h exposure in the ex vivo HPE model. Conclusion Exposure to P. falciparum-IE induces a detachment of the syncytiotrophoblast, disorganization of the stroma villi, and an increase in apoptosis, alterations that may be associated with adverse results such as intrauterine growth restriction and low birth weight.
Læs mere Tjek på PubMedMalaria Journal, 2.05.2024
Tilføjet 2.05.2024
Abstract Background Malaria has remained a persistent global health problem. Despite multiple government and donor initiatives to eradicate malaria and its detrimental effects on Uganda\'s health outcomes, the incidence of malaria is worrying as it appears higher than the average of 219 cases per 1000 for sub-Saharan Africa for the period 2017–2018. This study investigated the effect of public and private healthcare spending on the incidence of malaria in Uganda. Methods Employing time series data spanning over 20 years from the first quarter of 2000 to the last quarter of 2019, the study builds a model based on the Grossman framework for analysing demand for health. The estimation technique used was the ARDL approach that takes into account reverse causality and incidental relationships. Prior to the adoption of the technique, a bounds test was performed to determine whether the variables contained in the model have a long-term relationship. Several diagnostic tests for serial correlation, functional normality, and heteroskedastic specification error were carried out to verify the ARDL model\'s goodness of fit. Additionally, the cumulative sum of recursive (CUSUM) and cumulative sum of squares of recursive residuals (CUSUMSQ) were used to test model stability. Results The results indicate that in the long run, an increase in public spending of one percent significantly reduces malaria incidence by 0.196 at the 10 percent level of significance. On the other hand, there is no significant evidence of private health expenditure\'s effect on malaria incidence. However, in the short run, public spending reduces malaria incidence by a smaller magnitude of 0.158 percent relative to the long-run. Still, private expenditure is found to exhibit no significant effect. Additional findings point to the importance of GDP per capita and urban population growth in reducing malaria incidence, whereas female unemployment, income inequality, as well as female-headed household. In the short run, however, the female-headed households and urban population growth are found to significantly reduce malaria incidence while an improvement in regulatory quality decreases malaria incidence by 0.129 percent. Conclusions There is need for further government interventions to reduce malaria incidence in the country via budget allocation, as well as the strengthening of programmes to raise household income to support private health spending, in addition to the development of strategies to promote well-planned and organized urban centres.
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.05.2024
Tilføjet 2.05.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 5 Pages: 887-891
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.05.2024
Tilføjet 2.05.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 5 Pages: 892-901
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.05.2024
Tilføjet 2.05.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 5 Pages: 902-909
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 2.05.2024
Tilføjet 2.05.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 5 Pages: 921-924
Læs mere Tjek på PubMedMalaria Journal, 30.04.2024
Tilføjet 30.04.2024
Abstract Background Malaria treatment in sub-Saharan Africa is faced with challenges including unreliable supply of efficacious agents, substandard medicines coupled with high price of artemisinin-based combinations. This affects access to effective treatment increasing risk of malaria parasite resistance development and adverse drug events. This study investigated access to quality-assured artemisinin-based combination therapy (QAACT) medicines among clients of selected private drug-outlets in Uganda. Methods This was a cross sectional study where exit interviews were conducted among clients of private drug outlets in low and high malaria transmission settings in Uganda. This study adapted the World Health Organization/Health Action International (WHO/HAI) standardized criteria. Data was collected using a validated questionnaire. Data entry screen with checks was created in Epi-data ver 4.2 software and data entered in duplicate. Data was transferred to STATA ver 14.0 and cleaned prior to analysis. The analysis was done at 95% level of significance. Results A total of 1114 exit interviews were conducted among systematically sampled drug outlet clients. Over half, 54.9% (611/1114) of the participants were males. Majority, 97.2% (1083/1114) purchased an artemisinin-based combination anti-malarial. Most, 55.5% (618/1114) of the participants had a laboratory diagnosis of malaria. Majority, 77.9% (868/1114) of the participants obtained anti-malarial agents without a prescription. Less than a third, 27.7% (309/1114) of the participants obtained a QAACT. Of the participants who obtained QAACT, more than half 56.9% (173/309) reported finding the medicine expensive. The predictors of accessing a QAACT anti-malarial among drug outlet clients include type of drug outlet visited (aPR = 0.74; 95%CI 0.6, 0.91), not obtaining full dose (3-day treatment) of ACT (aPR = 0.49; 95%CI 0.33, 0.73), not finding the ACT expensive (aPR = 1.24; 95%CI 1.03, 1.49), post-primary education (aPR = 1.29; 95%CI 1.07,1.56), business occupation (aPR = 1.24; 95%CI 1.02,1.50) and not having a prescription (aPR = 0.76; 95%CI 0.63, 0.92). Conclusion Less than a third of the private drug outlet clients obtained a QAACT for management of malaria symptoms. Individuals who did not find artemisinin-based combinations to be expensive were more likely to obtain a QAACT anti-malarial. The Ministry of Health needs to conduct regular surveillance to monitor accessibility of QAACT anti-malarial agents under the current private sector copayment mechanism.
Læs mere Tjek på PubMedMalaria Journal, 30.04.2024
Tilføjet 30.04.2024
Abstract Background The decreasing residual efficacy of insecticides is an important factor when making decisions on insecticide choice for national malaria control programmes. The major challenge to using chemicals for vector control is the selection for the development of insecticide resistance. Since insecticide resistance has been recorded for most of the existing insecticides used for indoor residual spraying, namely, DDT, pyrethroids, organophosphates and carbamates, and new chemicals are necessary for the continued success of indoor residual spraying. The aim of this study was to assess the residual efficacy of Actellic 300CS, SumiShield™ 50WG and Fludora®Fusion by spraying on different wall surfaces. Methods One hundred and sixty-eight houses with different wall surface types (mud, cement, painted cement, and tin) which represented the rural house wall surface types in KwaZulu-Natal, South Africa were used to evaluate the residual efficacy of Actellic 300CS, SumiShield 50WG and Fludora®Fusion with DDT as the positive control. All houses were sprayed by experienced spray operators from the Malaria Control Programme. Efficacy of these insecticides were evaluated by contact bioassays against Anopheles arabiensis, a vector species. The residual efficacy of the insecticide formulations was evaluated against a susceptible insectary-reared population of An. arabiensis using WHO cone bioassays. Results Effectiveness of the three insecticides was observed up to 12 months post-spray. When assessing the achievement of 100% mortality over time, SumiShield performed significantly better than DDT on mud (OR 2.28, 95% CI 1.72–3.04) and painted cement wall types (OR 3.52, 95% CI 2.36–5.26). On cement wall types, Actellic was found to be less effective than DDT (OR 0.55, 95% CI 0.37–0.82) while Fludora®Fusion was less effective on tin wall types (OR 0.67, 95% CI 0.47–0.95). When compared to the combined efficacy of DDT on mud surfaces, SumiShield applied to each of the mud, cement and painted cement wall types and DDT applied to the cement wall types was found to be significantly more effective. These insecticides usually resulted in 100% mortality for up to 12 months with a delayed mortality period of 96–144 h, depending on the insecticide evaluated and the surface type sprayed. Conclusion Field evaluation of these insecticides have shown that Actellic, SumiShield and Fludora®Fusion are suitable replacements for DDT. Each of these insecticides can be used for malaria vector control, requiring just one spray round. These insecticides can be used in rotation or as mosaic spraying.
Læs mere Tjek på PubMedMalaria Journal, 30.04.2024
Tilføjet 30.04.2024
Abstract Introduction Introduction: Malaria continues to be the leading cause of hospitalization and death in Angola, a country in sub- Saharan Africa. In 2023, in the first quarter, 2,744,682 cases were registered, and of these 2,673 patients died due to malaria disease. Previous studies have shown that the ABO blood group can affect the progression of malaria to severe conditions after P. falciparum infection, while the sickle cell gene offers relative protection. Objective We investigated changes in the blood count according to blood groups (ABO/Rh) and sickle cell trait in patients with malaria in Luanda, capital of Angola. Methodology This was a longitudinal, prospective and observational study with 198 patients hospitalized for malaria. Results Of the 198 patients studied, 13(6.6%) were ABRh(+), 4(2.0%) were ARh(-), 49(24.7%) were ARh(+), 42(21, 2%) were BRh (+), 5(2.5%) were ORh(-) and 85(42.9%) were ORh(+). For sickle cell trait, 145(73.2%) were AA, 37(18.7%) were AS and 16(8.1%) were SS. No statistical relationship was observed between age group, sex, parasitemia, clinical picture, hematocrit, MCV, HCM, MCHC, leukocytes, NEUT, LINF and PTL values with blood groups (p0.05). There was no relationship between age, parasitemia, clinical condition, MCV, HCM and MCHC values, leukocytes, NEUT and LINF with sickle cell trait (p0.05). Conclusion It is imperative to differentiate patients with malaria based on blood groups and sickle cell trait, taking into account mainly the blood count parameters that demonstrate that there are patients who, depending on blood group or sickle cell trait, may react weakly to malaria infection regardless of the degree of parasitemia and medical prognosis.
Læs mere Tjek på PubMedMalaria Journal, 29.04.2024
Tilføjet 29.04.2024
Abstract Background Despite efforts made to reduce morbidity and mortality associated with malaria, especially in sub-Saharan Africa, malaria continues to be a public health concern that requires innovative efforts to reach the WHO-set zero malaria agenda. Among the innovations is the use of artemisinin-based combination therapy (ACT) that is effective against Plasmodium falciparum. Generic artemether–lumefantrine (AL) is used to treat uncomplicated malaria after appropriate diagnosis. AL is metabolized by the cytochrome P450 family of enzymes, such as CYP2B6, CYP3A4 and CYP3A5, which can be under pharmacogenetic influence. Pharmacogenetics affecting AL metabolism, significantly influence the overall anti-malarial activity leading to variable therapeutic efficacy. This study focused on generic AL drugs used in malarial treatment as prescribed at health facilities and evaluated pharmacogenomic influences on their efficacy. Methods Patients who have been diagnosed with malaria and confirmed through RDT and microscopy were recruited in this study. Blood samples were taken on days 1, 2, 3 and 7 for parasite count and blood levels of lumefantrine, artemisinin, desbutyl-lumefantrine (DBL), and dihydroartemisinin (DHA), the active metabolites of lumefantrine and artemether, respectively, were analysed using established methods. Pharmacogene variation analysis was undertaken using iPLEX microarray and PCR–RFLP. Results A total of 52 patients completed the study. Median parasite density from day 1 to 7 ranged from 0–2666/μL of blood, with days 3 and 7 recording 0 parasite density. Highest median plasma concentration for lumefantrine and desbutyl lumefantrine, which are the long-acting components of artemisinin-based combinations, was 4123.75 ng/mL and 35.87 ng/mL, respectively. Day 7 plasma lumefantrine concentration across all generic ACT brands was ≥ 200 ng/mL which potentially accounted for the parasitaemia profile observed. Monomorphism was observed for CYP3A4 variants, while there were observed variations in CYP2B6 and CYP3A5 alleles. Among the CYP3A5 genotypes, significant differences in genotypes and plasma concentration for DBL were seen on day 3 between 1/*1 versus *1/*6 (p = 0.002), *1/*3 versus *1/*6 (p = 0.006) and *1/*7 versus *1/*6 (p = 0.008). Day 7 plasma DBL concentrations showed a significant difference between *1/*6 and *1/*3 (p = 0.026) expressors. Conclusions The study findings show that CYP2B6 and CYP3A5 pharmacogenetic variations may lead to higher plasma exposure of AL metabolites.
Læs mere Tjek på PubMedMalaria Journal, 28.04.2024
Tilføjet 28.04.2024
Abstract Background Malaria is still a disease of global public health importance and children under-five years of age are the most vulnerable to the disease. Nigeria adopted the “test and treat” strategy in the national malaria guidelines as one of the ways to control malaria transmission. The level of adherence to the guidelines is an important indicator for the success or failure of the country’s roadmap to malaria elimination by 2030. This study aimed to assess the fidelity of implementation of the national guidelines on malaria diagnosis for children under-five years and examine its associated moderating factors in health care facilities in Rivers State, Nigeria. Methods This was a descriptive, cross-sectional study conducted in Port Harcourt metropolis. Data were collected from 147 public, formal private and informal private health care facilities. The study used a questionnaire developed based on Carroll’s Conceptual Framework for Implementation Fidelity. Frequency, mean and median scores for implementation fidelity and its associated factors were calculated. Associations between fidelity and the measured predictors were examined using Mann Whitney U test, Kruskal Wallis test, and multiple linear regression modelling using robust estimation of errors. Regression results are presented in adjusted coefficient (β) and 95% confidence intervals. Results The median (IQR) score fidelity score for all participants was 65% (43.3, 85). Informal private facilities (proprietary patent medicine vendors) had the lowest fidelity scores (47%) compared to formal private (69%) and public health facilities (79%). Intervention complexity had a statistically significant inverse relationship to implementation fidelity (β = − 1.89 [− 3.42, − 0.34]). Increase in participant responsiveness (β = 8.57 [4.83, 12.32]) and the type of malaria test offered at the facility (e.g., RDT vs. no test, β = 16.90 [6.78, 27.03]; microscopy vs. no test, β = 21.88 [13.60, 30.16]) were positively associated with fidelity score. Conclusions This study showed that core elements of the “test and treat” strategy, such as testing all suspected cases with approved diagnostic methods before treatment, are still not fully implemented by health facilities. There is a need for strategies to increase fidelity, especially in the informal private health sector, for malaria elimination programme outcomes to be achieved.
Læs mere Tjek på PubMedMalaria Journal, 28.04.2024
Tilføjet 28.04.2024
Abstract Background Malaria contributes to excess child mortality in The Gambia. Children under five are at risk of severe malaria and death if not treated promptly and appropriately. It is crucial that a child with fever receive appropriate care from a trained provider. The aim was to identify influences on child fever care-seeking in The Gambia to inform malaria control strategies. Methods This cross-sectional analysis of The Gambia 2019–20 Demographic and Health Survey used logistic regression analysis to identify associations between source of care for a child with fever (public or private healthcare provider, other, or no treatment) and mother, child, and household characteristics. Results Only 52.0% of mothers sought care from a trained healthcare provider for a child with fever—45.1% from a public facility and 7.0% from the private sector. 35.2% of mothers did not seek treatment. Mothers in urban households were 2.67 times as likely (aOR, 95% CI 1.504–4.736) as mothers in rural households to seek care from an informal source (e.g., pharmacy) versus not seeking treatment, and 0.29 times as likely (aOR, 95% CI 0.165–0.515) as mothers in rural households to seek care from a public provider versus informal source. Mothers in wealthier households were 2.30 times as likely (aOR, 95% CI 1.274–4.164) as mothers in poorer households to seek care from an informal source versus no treatment and half as likely as mothers in poorer households to seek care from a public provider versus informal source (aOR 0.53, 95% CI 0.291–0.959). Conclusions Maintaining The Gambia’s malaria control achievements will require the active engagement and oversight of private pharmacies along with continued integrated community case management to reach mothers who do not seek care for a child with fever, and remove challenges to seeking appropriate care from trained providers. Whether influenced by convenience, costs, perceived urgency, or other factors, given the likelihood of urban mothers and mothers in wealthier households to seek care from private pharmacies, it will be necessary to incorporate private pharmacies into malaria control strategies while building public sector capacity and workforce, and initiating more effective attitude and behavioural change among mothers and households.
Læs mere Tjek på PubMedKassoum Kayentao, Aissata Ongoiba, Anne C. Preston, Sara A. Healy, Zonghui Hu, Jeff Skinner, Safiatou Doumbo, Jing Wang, Hamidou Cisse, Didier Doumtabe, Abdrahamane Traore, Hamadi Traore, Adama Djiguiba, Shanping Li, Mary E. Peterson, Shinyi Telscher, Azza H. Idris, William C. Adams, Adrian B. McDermott, Sandeep Narpala, Bob C. Lin, Leonid Serebryannyy, Somia P. Hickman, Andrew J. McDougal, Sandra Vazquez, Matthew Reiber, Judy A. Stein, Jason G. Gall, Kevin Carlton, Philipp Schwabl, Siriman Traore, Mamadou Keita, Amatigué Zéguimé, Adama Ouattara, M’Bouye Doucoure, Amagana Dolo, Sean C. Murphy, Daniel E. Neafsey, Silvia Portugal, Abdoulaye Djimdé, Boubacar Traore, Robert A. Seder, and Peter D. Cromptonthe Mali Malaria mAb Trial Team*From the Malaria Research and Training Center, Mali International Center of Excellence in Research, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali (K.K., A. Ongoiba, S.D., D.D., A.T., H.T., A. Djiguiba, S. Traore, M.K., A.Z., A. Ouattara, M.D., A. Dolo, A. Djimdé, B.T.); the Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, Division of Intramural Research (A.C.P., S.A.H., J.S., H.C., S.L., M.E.P., P.D.C.), and the Biostatistics Research Branch, Division of Clinical Research (Z.H.), National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, the Vaccine Research Center (S. Telscher, A.H.I., W.C.A., A.B.M., S.N., B.C.L., L.S., S.P.H., A.J.M., S.V., M.R., J.A.S., J.G.G., K.C., R.A.S.), National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, and the Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research, Frederick (J.W.) — all in Maryland; the Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston (P.S., D.E.N.); the Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology, and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle (S.C.M.); and the Max Planck Institute for Infection Biology, Berlin (S.P.).
New England Journal of Medicine, 27.04.2024
Tilføjet 27.04.2024
Trevor MundelFrom the Bill and Melinda Gates Foundation, Seattle.
New England Journal of Medicine, 27.04.2024
Tilføjet 27.04.2024
Malaria Journal, 27.04.2024
Tilføjet 27.04.2024
Abstract Background Anopheles coluzzii is a primary vector of malaria found in West and Central Africa, but its presence has hitherto never been documented in Kenya. A thorough understanding of vector bionomics is important as it enables the implementation of targeted and effective vector control interventions. Malaria vector surveillance efforts in the country have tended to focus on historically known primary vectors. The current study sought to determine the taxonomic status of samples collected from five different malaria epidemiological zones in Kenya as well as describe the population genetic structure and insecticide resistance profiles in relation to other An. coluzzii populations. Methods Mosquitoes were sampled as larvae from Busia, Kwale, Turkana, Kirinyaga and Kiambu counties, representing the range of malaria endemicities in Kenya, in 2019 and 2021 and emergent adults analysed using Whole Genome Sequencing (WGS) data processed in accordance with the Anopheles gambiae 1000 Genomes Project phase 3. Where available, historical samples from the same sites were included for WGS. Comparisons were made with An. coluzzii cohorts from West and Central Africa. Results This study reports the detection of An. coluzzii for the first time in Kenya. The species was detected in Turkana County across all three time points from which samples were analyzed and its presence confirmed through taxonomic analysis. Additionally, there was a lack of strong population genetic differentiation between An. coluzzii from Kenya and those from the more northerly regions of West and Central Africa, suggesting they represent a connected extension to the known species range. Mutations associated with target-site resistance to DDT and pyrethroids and metabolic resistance to DDT were found at high frequencies up to 64%. The profile and frequencies of the variants observed were similar to An. coluzzii from West and Central Africa but the ace-1 mutation linked to organophosphate and carbamate resistance present in An. coluzzii from coastal West Africa was absent in Kenya. Conclusions These findings emphasize the need for the incorporation of genomics in comprehensive and routine vector surveillance to inform on the range of malaria vector species, and their insecticide resistance status to inform the choice of effective vector control approaches.
Læs mere Tjek på PubMedMalaria Journal, 27.04.2024
Tilføjet 27.04.2024
Abstract Background In Madagascar, the districts of Antsirabe II, Faratsiho and Antsiranana I have relatively low malaria incidence rates and have been selected by the National Malaria Control Programme for pilot elimination strategies. The districts have residual transmission despite increasing coverage and quality of malaria services. This study sought to identify priority subpopulations at highest risk for malaria and collect information on intervention preferences and methods that will inform subnational tailoring of malaria service delivery. Methods This mixed methods study employed (i) a quantitative malaria risk factor assessment in Antsirabe II and Faratsiho comprising a test-negative frequency matched case–control study and a qualitative risk factor assessment in Antsiranana I; and (ii) a qualitative formative assessment in all three districts. For the case–control study, a mixed effects logistic regression was used with age, sex and district included as fixed effects and health facility included as a random effect. The qualitative risk factor assessment used semi-structured interview guides and key informant interviews. For the qualitative formative assessment in the three districts, a summary report was generated following semi-structured interviews and focus group discussions with high-risk populations (HRPs) and stakeholders. Results In Antsirabe II and Faratsiho districts, rice agriculture workers, outdoor/manual workers, particularly miners, and those with jobs that required travel or overnight stays, especially itinerant vendors, had higher odds of malaria infection compared to other (non-rice) agricultural workers. In Antsiranana I, respondents identified non-rice farmers, mobile vendors, and students as HRPs. Risk factors among these groups included overnight stays and travel patterns combined with a lack of malaria prevention tools. HRPs reported treatment cost and distance to the health facility as barriers to care and expressed interest in presumptive treatment and involvement of gatekeepers or people who have influence over intervention access or participation. Conclusions The study results illustrate the value of in-depth assessments of risk behaviours, access to services and prevention tools, surveillance and prevention strategies, and the involvement of gatekeepers in shaping subnational tailoring to reach previously unreached populations and address residual transmission in elimination settings.
Læs mere Tjek på PubMedMalaria Journal, 27.04.2024
Tilføjet 27.04.2024
Abstract Background The increased availability and use of malaria rapid diagnostic test (RDT) by primary healthcare (PHC) workers has made universal diagnostic testing before malaria treatment more feasible. However, to meaningfully resolve the problem of over-treatment with artemisinin-based combination therapy and the heightened risk of selection pressure and drug resistance, there should be appropriate response (non-prescription of anti-malarial drugs) following a negative RDT result by PHC workers. This study explored the determinants of the use of RDT and anti-malarial drug prescription practices by PHC workers in Ebonyi state, Nigeria. Methods Between March 2 and 10, 2020, three focus group discussions were conducted in English with 23 purposively-selected consenting PHC workers involved in the diagnosis and treatment of malaria. Data was analysed thematically as informed by the method by Braun and Clarke. Results The determinants of the use of RDT for malaria diagnosis were systemic (RDT availability and patient load), provider related (confidence in RDT and the desire to make correct diagnosis, PHC worker’s knowledge and training, and fear to prick a patient), client related (fear of needle prick and refusal to receive RDT, and self-diagnosis of malaria, based on symptoms, and insistence on not receiving RDT), and RDT-related (the ease of conducting and interpreting RDT). The determinants of anti-malarial drug prescription practices were systemic (drug availability and cost) and drug related (effectiveness and side-effects of the drugs). The determinants of the prescription of anti-malarial drugs following negative RDT were provider related (the desire to make more money and limited confidence in RDT) and clients’ demand while unnecessary co-prescription of antibiotics with anti-malarial drugs following positive RDT was determined by the desire to make more money. Conclusions This evidence highlights many systemic, provider, client, and RDT/drug related determinants of PHC workers’ use of RDT and anti-malarial drug prescription practices that should provide tailored guidance for relevant health policy actions in Ebonyi state, Nigeria, and similar settings.
Læs mere Tjek på PubMedKwaku Poku Asante, Don P Mathanga, Paul Milligan, Samuel Akech, Abraham Oduro, Victor Mwapasa, Kerryn A Moore, Titus K Kwambai, Mary J Hamel, Thomas Gyan, Nelli Westercamp, Atupele Kapito-Tembo, Patricia Njuguna, Daniel Ansong, Simon Kariuki, Tisungane Mvalo, Paul Snell, David Schellenberg, Paul Welega, Lucas Otieno, Alfred Chimala, Edwin A Afari, Philip Bejon, Kenneth Maleta, Tsiri Agbenyega, Robert W Snow, Madaliso Zulu, Jobiba Chinkhumba, Aaron M Samuels, Malaria Vaccine Programme Evaluation Partners
Lancet, 26.04.2024
Tilføjet 26.04.2024
In the first 2 years of implementation of RTS,S, the three primary doses were effectively deployed through national immunisation programmes. There was no evidence of the safety signals that had been observed in the phase 3 trial, and introduction of the vaccine was associated with substantial reductions in hospital admission with severe malaria. Evaluation continues to assess the impact of four doses of RTS,S.
Læs mere Tjek på PubMedMalaria Journal, 26.04.2024
Tilføjet 26.04.2024
Malaria Journal, 26.04.2024
Tilføjet 26.04.2024
Abstract Background There are giant steps taken in the introduction of the novel malaria vaccine poised towards reducing mortality and morbidity associated with malaria. Objectives This study aimed to determine the knowledge of malaria vaccine and factors militating against willingness to accept the vaccine among mothers presenting in nine hospitals in Enugu metropolis. Methods This was a cross-sectional study carried out among 491 mothers who presented with their children in nine hospitals in Enugu metropolis, South-East Nigeria. A pre-tested and interviewer-administered questionnaire was used in this study. Results A majority of the respondents, 72.1% were aware of malaria vaccine. A majority of the respondents, 83.1% were willing to receive malaria vaccine. Similarly, a majority of the mothers, 92.9%, were willing to vaccinate baby with the malaria vaccine, while 81.1% were willing to vaccinate self and baby with the malaria vaccine. The subjects who belong to the low socio-economic class were five times less likely to vaccinate self and baby with malaria vaccine when compared with those who were in the high socio-economic class (AOR = 0.2, 95% CI 0.1–0.5). Mothers who had good knowledge of malaria vaccination were 3.3 times more likely to vaccinate self and baby with malaria vaccine when compared with those who had poor knowledge of malaria vaccination (AOR = 3.3, 95% CI 1–6–6.8). Conclusion Although the study documented a high vaccine acceptance among the mothers, there exists a poor knowledge of the malaria vaccine among them.
Læs mere Tjek på PubMedMalaria Journal, 26.04.2024
Tilføjet 26.04.2024
Abstract Background Pregnancy Associated Malaria (PAM) include malaria in pregnancy (MiP), placental malaria (PM), and congenital malaria (CM). The evidence available in Colombia on PAM focuses on one of the presentations (MiP, PM or CM), and no study longitudinally analyses the infection from the pregnant woman, passing through the placenta, until culminating in the newborn. This study determined the frequency of MiP, PM, and CM caused by Plasmodium vivax, Plasmodium falciparum, or mixed infections, according to Thick Blood Smear (TBS) and quantitative Polymerase Chain Reaction (qPCR). Identifying associated factors of PAM and clinical-epidemiological outcomes in northwestern Colombia. Methods Prospective study of 431 pregnant women, their placenta, and newborns registered in the data bank of the research Group “Salud y Comunidad César Uribe Piedrahíta” which collected information between 2014 and 2020 in endemic municipalities of the departments of Córdoba and Antioquia. The frequency of infection was determined with 95% confidence intervals. Comparisons were made with the Chi-square test, Student t-test, prevalence ratios, and control for confounding variables by log-binomial regression. Results The frequency of MiP was 22.3% (4.6% using TBS), PM 24.8% (1.4% using TBS), and CM 11.8% (0% using TBS). Using TBS predominated P. vivax. Using qPCR the proportions of P. vivax and P. falciparum were similar for MiP and PM, but P. falciparum predominated in CM. The frequency was higher in nulliparous, and women with previous malaria. The main clinical effects of PAM were anaemia, low birth weight, and abnormal APGAR score. Conclusions The magnitude of infections was not detected with TBS because most cases were submicroscopic (TBS-negative, qPCR-positive). This confirmed the importance of improving the molecular detection of cases. PAM continue being underestimated in the country due to that in Colombia the control programme is based on TBS, despite its outcomes on maternal, and congenital health.
Læs mere Tjek på PubMedMalaria Journal, 26.04.2024
Tilføjet 26.04.2024
Abstract Background The residual activity of a clothianidin + deltamethrin mixture and clothianidin alone in IRS covered more than the period of malaria transmission in northern Benin. The aim of this study was to show whether the prolonged residual efficacy of clothianidin-based products resulted in a greater reduction in vector populations and subsequent malaria transmission compared with the shorter residual efficacy of pirimiphos-methyl. Methods Human bait mosquito collections by local volunteers and pyrethrum spray collections were used in 6 communes under IRS monitoring and evaluation from 2019 to 2021. ELISA/CSP and species PCR tests were performed on Anopheles gambiae sensu lato (s.l.) to determine the infectivity rate and subspecies by commune and year. The decrease in biting rate, entomological inoculation rate, incidence, inhibition of blood feeding, resting density of An. gambiae s.l. were studied and compared between insecticides per commune. Results The An. gambiae complex was the major vector throughout the study area, acounting for 98.71% (19,660/19,917) of all Anopheles mosquitoes collected. Anopheles gambiae s.l. collected was lower inside treated houses (45.19%: 4,630/10,245) than outside (54.73%: 5,607/10,245) after IRS (p
Læs mere Tjek på PubMedDeus S. Ishengoma, Roly Gosling, Rosario Martinez-Vega, Khalid B. Beshir, Jeffrey A. Bailey, John Chimumbwa, Colin Sutherland, Melissa D. Conrad, Fitsum G. Tadesse, Jonathan J. Juliano, Moses R. Kamya, Wilfred F. Mbacham, Didier Ménard, Philip J. Rosenthal, Jaishree Raman, Allison Tatarsky, Sofonias K. Tessema, David A. Fidock, Abdoulaye A. Djimde
Nature, 25.04.2024
Tilføjet 25.04.2024
Kazutoyo MiuraYevel Flores-GarciaCarole A. LongFidel Zavala1Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA2Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Malaria Research Institute, Baltimore, Maryland, USA, Louisa A. Messenger, Gordon A. AwandareKwadwo Asamoah Kusi
Clinical Microbiology Reviews, 24.04.2024
Tilføjet 24.04.2024
Malaria Journal, 23.04.2024
Tilføjet 23.04.2024
Pacifique Karekezi, Jean Damascene Nzabakiriraho, Ezra Gayawan
PLoS One Infectious Diseases, 23.04.2024
Tilføjet 23.04.2024
by Pacifique Karekezi, Jean Damascene Nzabakiriraho, Ezra Gayawan In sub-Saharan Africa, malaria and anemia contribute substantially to the high burden of morbidity and mortality among under-five children. In Rwanda, both diseases have remained public health challenge over the years in spite of the numerous intervention programs and policies put in place. This study aimed at understanding the geographical variations between the joint and specific risks of both diseases in the country while quantifying the effects of some socio-demographic and climatic factors. Using data extracted from Rwanda Demographic and Health Survey, a shared component model was conceived and inference was based on integrated nested Laplace approximation. The study findings revealed similar spatial patterns for the risk of malaria and the shared risks of both diseases, thus confirming the strong link between malaria and anaemia. The spatial patterns revealed that the risks for contracting both diseases are higher among children living in the districts of Rutsiro, Nyabihu, Rusizi, Ruhango, and Gisagara. The risks for both diseases are significantly associated with type of place of residence, sex of household head, ownership of bed net, wealth index and mother’s educational attainment. Temperature and precipitation also have substantial association with both diseases. When developing malaria intervention programs and policies, it is important to take into account climatic and environmental variability in Rwanda. Also, potential intervention initiatives focusing on the lowest wealth index, children of uneducated mothers, and high risky regions need to be reinforced.
Læs mere Tjek på PubMedMalaria Journal, 21.04.2024
Tilføjet 21.04.2024
Abstract Background Microsporidia MB, an endosymbiont naturally found in Anopheles mosquitoes inhibits transmission of Plasmodium and is a promising candidate for a transmission-blocking strategy that may involve mosquito release. A rapid assessment was carried out to develop insight into sociodemographic factors, public health concerns, and malaria awareness, management, and prevention practices with the willingness to accept and participate in Microsporidia MB-based transmission-blocking strategy to develop an informed stakeholder engagement process. Methods The assessment consisted of a survey conducted in two communities in western Kenya that involved administering a questionnaire consisting of structured, semi-structured, and open questions to 8108 household heads. Results There was an overall high level of willingness to accept (81%) and participate in the implementation of the strategy (96%). Although the willingness to accept was similar in both communities, Ombeyi community was more willing to participate (OR 22, 95% CI 13–36). Women were less willing to accept (OR 0.8, 95% CI 0.7–0.9) compared to men due to fear of increased mosquito bites near homes. Household heads with incomplete primary education were more willing to accept (OR 1.6, 95% CI 01.2–2.2) compared to those educated to primary level or higher. Perceiving malaria as a moderate or low public health issue was also associated with a lower willingness to accept and participate. Experience of > 3 malaria cases in the family over the last six months and knowledge that malaria is transmitted by only mosquito bites, increased the willingness to accept but reduced the willingness to participate. Awareness of malaria control methods based on mosquitoes that cannot transmit malaria increases the willingness to participate. Conclusion The study showed a high level of willingness to accept and participate in a Microsporidia MB-based strategy in the community, which is influenced by several factors such as community, disease risk perception, gender, education level, knowledge, and experience of malaria. Further research will need to focus on understanding the concerns of women, educated, and employed community members, and factors that contribute to the lower disease risk perception. This improved understanding will lead to the development of an effective communication strategy.
Læs mere Tjek på PubMedAyumi E. Pottenger, Debashish Roy, Selvi Srinivasan, Thomas E. J. Chavas, Vladmir Vlaskin, Duy-Khiet Ho, Vincent C. Livingston, Mahdi Maktabi, Hsiuling Lin, Jing Zhang, Brandon Pybus, Karl Kudyba, Alison Roth, Peter Senter, George Tyson, Hans E. Huber, David Wesche, Rosemary Rochford, Paul A. Burke, Patrick S. Stayton
Science Advances, 20.04.2024
Tilføjet 20.04.2024
Malaria Journal, 20.04.2024
Tilføjet 20.04.2024
Abstract Background In malaria endemic regions of the Peruvian Amazon, rainfall together with river level and breeding site availability drive fluctuating vector mosquito abundance and human malaria cases, leading to temporal heterogeneity. The main variables influencing spatial transmission include location of communities, mosquito behaviour, land use/land cover, and human ecology/behaviour. The main objective was to evaluate seasonal and microgeographic biting behaviour of the malaria vector Nyssorhynchus (or Anopheles) darlingi in Amazonian Peru and to investigate effects of seasonality on malaria transmission. Methods We captured mosquitoes from 18:00 to 06:00 h using Human Landing Catch in two riverine (Lupuna, Santa Emilia) and two highway (El Triunfo, Nuevo Horizonte) communities indoors and outdoors from 8 houses per community, during the dry and rainy seasons from February 2016 to January 2017. We then estimated parity rate, daily survival and age of a portion of each collection of Ny. darlingi. All collected specimens of Ny. darlingi were tested for the presence of Plasmodium vivax or Plasmodium falciparum sporozoites using real-time PCR targeting the small subunit of the 18S rRNA. Results Abundance of Ny. darlingi varied across village, season, and biting behaviour (indoor vs outdoor), and was highly significant between rainy and dry seasons (p
Læs mere Tjek på PubMedMalaria Journal, 20.04.2024
Tilføjet 20.04.2024
Abstract Background Sporozoites (SPZ), the infective form of Plasmodium falciparum malaria, can be inoculated into the human host skin by Anopheline mosquitoes. These SPZ migrate at approximately 1 µm/s to find a blood vessel and travel to the liver where they infect hepatocytes and multiply. In the skin they are still low in number (50–100 SPZ) and vulnerable to immune attack by antibodies and skin macrophages. This is why whole SPZ and SPZ proteins are used as the basis for most malaria vaccines currently deployed and undergoing late clinical testing. Mosquitoes typically inoculate SPZ into a human host between 14 and 25 days after their previous infective blood meal. However, it is unknown whether residing time within the mosquito affects SPZ condition, infectivity or immunogenicity. This study aimed to unravel how the age of P. falciparum SPZ in salivary glands (14, 17, or 20 days post blood meal) affects their infectivity and the ensuing immune responses. Methods SPZ numbers, viability by live/dead staining, motility using dedicated sporozoite motility orienting and organizing tool software (SMOOT), and infectivity of HC-04.j7 liver cells at 14, 17 and 20 days after mosquito feeding have been investigated. In vitro co-culture assays with SPZ stimulated monocyte-derived macrophages (MoMɸ) and CD8+ T-cells, analysed by flow cytometry, were used to investigate immune responses. Results SPZ age did not result in different SPZ numbers or viability. However, a markedly different motility pattern, whereby motility decreased from 89% at day 14 to 80% at day 17 and 71% at day 20 was observed (p ≤ 0.0001). Similarly, infectivity of day 20 SPZ dropped to ~ 50% compared with day 14 SPZ (p = 0.004). MoMɸ were better able to take up day 14 SPZ than day 20 SPZ (from 7.6% to 4.1%, p = 0.03) and displayed an increased expression of pro-inflammatory CD80, IL-6 (p = 0.005), regulatory markers PDL1 (p = 0.02), IL-10 (p = 0.009) and cytokines upon phagocytosis of younger SPZ. Interestingly, co-culture of these cells with CD8+ T-cells revealed a decreased expression of activation marker CD137 and cytokine IFNγ compared to their day 20 counterparts. These findings suggest that older (day 17–20) P. falciparum SPZ are less infectious and have decreased immune regulatory potential. Conclusion Overall, this data is a first step in enhancing the understanding of how mosquito residing time affects P. falciparum SPZ and could impact the understanding of the P. falciparum infectious reservoir and the potency of whole SPZ vaccines.
Læs mere Tjek på PubMedAngélica M. Rosado-QuiñonesEmilee E. Colón-LorenzoZarna Rajeshkumar PalaJürgen BoschKarl KudybaHeather KudybaSusan E. LeedNorma RoncalAbel Baerga-OrtizAbiel Roche-LimaYamil GerenaDavid A. FidockAlison RothJoel Vega-RodríguezAdelfa E. Serrano1Department of Microbiology and Medical Zoology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico2Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA3Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, USA4InterRayBio, LLC, Cleveland, Ohio, USA5Department of Drug Discovery, Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA6Department of Biochemistry, University of Puerto Rico School of Medicine, San Juan, Puerto Rico7RCMI Program, Medical Science Campus, University of Puerto Rico, San Juan, Puerto Rico8Department of Pharmacology and Toxicology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico9Department of Microbiology and Immunology, Columbia University, New York, New York, USA10Division of Infectious Diseases, Department of Medicine, Center for Malaria Therapeutics and Antimicrobial Resistance, Columbia University Medical Center, New York, New York, USA, Audrey Odom John
Antimicrobial Agents And Chemotherapy, 20.04.2024
Tilføjet 20.04.2024
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 PubMed