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Malaria Journal, 31.10.2024
Tilføjet 31.10.2024
Abstract Background Since 2015, malaria vector control on Bioko Island has relied heavily upon long-lasting insecticidal nets (LLIN) to complement other interventions. Despite significant resources utilised, however, achieving and maintaining high coverage has been elusive. Here, core LLIN indicators were used to assess and redefine distribution strategies. Methods LLIN indicators were estimated for Bioko Island between 2015 and 2022 using a 1x1 km grid of areas. The way these indicators interacted was used to critically assess coverage targets. Particular attention was paid to spatial heterogeneity and to differences between urban Malabo, the capital, and the rural periphery. Results LLIN coverage according to all indicators varied substantially across areas, decreased significantly soon after mass distribution campaigns (MDC) and, with few exceptions, remained consistently below the recommended target. Use was strongly correlated with population access, particularly in Malabo. After a change in strategy in Malabo from MDC to fixed distribution points, use-to-access showed significant improvement, indicating those who obtained their nets from these sources were more likely to keep them and use them. Moreover, their use rates were significantly higher than those of whom sourced their nets elsewhere. Conclusions Striking a better balance between LLIN distribution efficiency and coverage represents a major challenge as LLIN retention and use rates remain low despite high access resulting from MDC. The cost-benefit of fixed distribution points in Malabo revealed significant advantages, offering a viable alternative for ensuring access to LLINs to those who use them.
Læs mere Tjek på PubMedBMC Infectious Diseases, 31.10.2024
Tilføjet 31.10.2024
Abstract Background Insecticides are a crucial component of vector control. However, resistance constitute a threat on their efficacy and the gains obtained over the years through malaria vector control. In Gabon, little data on phenotypic insecticide resistance in Anopheles vectors are published, compromising the rational implementation of resistance management strategies. We assessed the susceptibility to pyrethroids, carbamates and organophosphates of Anopheles gambiae sensu lato (s.l.) and discuss the mechanisms involved in the pyrethroid resistance-phenotype. Methods A. gambiae s.l. larvae were collected from breeding sites in Lambaréné. Emerging adults were used in WHO tube assays at an insecticide concentration that defines resistance (diagnostic concentration). Subsequently, deltamethrin and permethrin were used at 5x and 10x diagnostic concentrations and after preexposure with the cytochrome p450 (and glutathione S-transferase) inhibitor piperonyl butoxide (PBO). A subset of mosquitoes was typed by molecular methods and screened using Taqman assays for mutations conferring target site resistance at the Voltage-gated sodium channel 1014 (Vgsc-1014) locus and the acetylcholinesterase (Ace-1) gene. Results All mosquitoes were A. gambiae sensu stricto (s.s.) and resistant to permethrin, deltamethrin and alphacypermethrin (mortality less than 98%). However, mosquitoes were susceptible to malathion but resistant to bendiocarb. The level of resistance was high for permethrin and at least moderate for deltamethrin. Pre-exposure to PBO significantly increased the mortality of resistant mosquitoes (P
Læs mere Tjek på PubMedMalaria Journal, 30.10.2024
Tilføjet 30.10.2024
Abstract Background Reports on the impact of COVID-19 pandemic on the quality of malaria care and burden in sub Saharan Africa have provided a mixed picture to date. The impact of the 2nd (Delta) and 3rd (Omicron) COVID-19 waves on outpatient malaria indicators and case management practices was assessed at three public health facilities with varying malaria transmission intensities in Uganda. Methods Individual level data from all patients presenting to the out-patient departments (OPD) of the three facilities (Kasambya, Walukuba and Lumino) between January 2019 and February 2022 were included in the analysis. Outcomes of interest included total number of outpatient (OPD) visits, proportion of patients suspected to have malaria, proportion of suspected malaria cases tested with a malaria diagnostic test, test positivity rates (TPR) and proportion of malaria cases prescribed artemether-lumefantrine (AL). Using the pre-COVID-19 trends between January 2019 and February 2020, interrupted time series analysis was used to predict the expected trends for these study outcomes during the 2nd wave (May 2021–August 2021) and 3rd wave (November 2021–February 2022). The observed trends of the study outcomes were compared with the expected trends. Results There were no significant differences between the observed versus expected overall outpatient visits in the 2nd wave, however, a significant decline in OPD attendance was observed during the 3rd wave (15,101 vs 31,154; incidence rate ratio (IRR) = 0.48 [0.41–0.56]). No significant differences in the overall observed versus expected proportions of suspected malaria cases and test positivity rates in both COVID waves. However, a significant decrease in the overall proportion of suspected malaria cases tested with a malaria diagnostic test was observed during the 3rd wave (99.86% vs 99.99%; relative percent ratio [RPR] = 0.99 [0.99–0.99]). Finally, a significant decline in the overall proportion of malaria cases prescribed AL was observed during the 2nd wave (94.99% vs 99.85%; RPR = 0.95 [0.92–0.98]) but not the 3rd wave. Conclusion Significant declines in OPD attendance and suspected malaria cases tested with malaria diagnostic test were observed during the 3rd COVID-19 wave, while AL prescription significantly reduced during the 2nd COVID-19 wave. These findings add to the body of knowledge highlighting the adverse impact of COVID-19 pandemic on the malaria which could explain the increase in the malaria burden observed during this period.
Læs mere Tjek på PubMedMalaria Journal, 30.10.2024
Tilføjet 30.10.2024
Abstract Background The use of insecticide-treated nets (ITNs) is a strategy recommended by the World Health Organization (WHO) for malaria prevention. In Nigeria, ITNs have been periodically distributed since 2007 through campaigns. Campaign activities and assets are typically tracked using either a paper-based or digital system. In 2017, a digital approach was introduced in Ondo state for tracking attendance at training sessions as part of the ITN campaign. Following the success of the 2017 introduction, subsequent campaigns planned to digitise other aspects of the campaign to improve accountability and efficiency of the ITN distribution. The COVID-19 pandemic posed additional challenges for the ITN distribution planned for 2021 and adaptations were made to the programme strategy to ensure the campaign could go ahead safely. This article presents lessons and experiences from the 2021 ITN distribution campaign in Ondo state, Nigeria. Methods The campaign used RedRose, a customised mobile application, to monitor the planning and delivery of the campaign, collect household information including training personnel and tracking the transfer of ITNs between distribution hubs and households. ITNs were delivered through a single-phase door-to-door distribution strategy. Results The campaign distributed 2,965,125 ITNs covering 1,057,577 households across Ondo state. The digital application was beneficial for monitoring the quality of implementation and tracking assets and staff to ensure safety.. The single-phase door-to-door approach was more convenient for households compared to fixed-point distribution but increased the workload for mobilization and distribution teams. Conclusions Single phase door-to-door strategy using digital tools was an effective method to increase coverage of ITNs while closely tracking the progress of distribution campaigns. High-quality population data are needed to further improve the planning and implementation of ITN campaigns and other health interventions.
Læs mere Tjek på PubMedBMC Infectious Diseases, 30.10.2024
Tilføjet 30.10.2024
Abstract Background Plasmodium falciparum merozoite surface proteins 1 (PfMSP1) and 2 (PfMSP2) are potential candidates for malaria vaccine development. However, the genetic diversity of these genes in the global P. falciparum population presents a significant challenge in developing an effective vaccine. Hence, understanding the genetic diversity and evolutionary trends in the global P. falciparum population is crucial. Methods This study analyzed the genetic variations and evolutionary changes of pfmsp1 and pfmsp2 in P. falciparum isolates from the Central Highland and South-Central regions of Vietnam. DNASTAR and MEGA7 programs were utilized for analyses. The polymorphic nature of global pfmsp1 and pfmsp2 was also investigated. Results A total of 337 sequences of pfmsp1 and 289 sequences of pfmsp2 were obtained. The pfmsp1 and pfmsp2 from Vietnam revealed a higher degree of genetic homogeneity compared to those from other malaria-endemic countries. Remarkably, the allele diversity patterns of Vietnam pfmsp1 and pfmsp2 differed significantly from those of neighboring countries in the Greater Mekong Subregion. Declines in allele diversity and polymorphic patterns of Vietnam pfmsp1 and pfmsp2 were observed. Conclusions The Vietnam P. falciparum population might be genetically isolated from the parasite populations in other neighboring GMS countries, likely due to geographical barriers and distinct evolutionary pressures. Furthermore, bottleneck effects or selective sweeps may have contributed to the genetic homogeneity of Vietnam pfmsp1 and pfmsp2.
Læs mere Tjek på PubMedNicholas J. AriscoCassio PeterkaCesar DinizBurton H. SingerMarcia C. CastroaDepartment of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA 02115bSuperintendência de Vigilância em Saúde do Amapá, Governo do Estado do Amapá, Macapá, AP 68902-865, BrazilcEmerging Pathogens Institute, University of Florida, Gainesville, FL 32610
Proceedings of the National Academy of Sciences, 30.10.2024
Tilføjet 30.10.2024
Proceedings of the National Academy of Sciences, Volume 121, Issue 44, October 2024.
Læs mere Tjek på PubMedNsa Dada, Victoria J. Simpson, Lucas N. Amenga-Etego, Eniyou Oriero, Olivo Miotto, Mili Estee Torok, Elijah O. Juma, Nana Aba Williams, Shavanthi Rajatileka, Cristina V. Ariani, Jaishree Raman, Deus S. Ishengoma
Trends in Parasitology, 30.10.2024
Tilføjet 30.10.2024
Integrated malaria molecular surveillance (iMMS) systems are essential for Africa\'s expanding malaria genomics initiatives. Here we highlight a few initiatives and demonstrate how iMMS can support evidence-based decisions and policies for National Malaria Programs and other malaria control stakeholders. We conclude with key considerations for advancing these malaria genomics initiatives towards sustainable iMMS.
Læs mere Tjek på PubMedBMC Infectious Diseases, 29.10.2024
Tilføjet 29.10.2024
Abstract Background Anemia is a common complication of HIV infected children and it is enabling HIV disease progression, and decreasing survival. In Ethiopia, there is limited evidence on the prevalence of anemia and its associated factors among HIV infected children particularly in the Awi Zone. Therefore, this study aimed to assess the magnitude and associated factors of anemia among HIV infected children on ART aged from 6 months to 15 year-old in ART Clinic, Awi-Zone, Ethiopia. Objective To assess the magnitude and associated factors of anemia among HIV infected children on antiretroviral therapy in Awi zone health facilities, Northwest, Ethiopia, 2022. Methods A facility based cross-sectional study design was conducted from October to December 2022. A simple random sampling method was used to select the study participants. Descriptive statistics, including frequencies and proportions was used to summarize the study variables and data had been entered in to Epi data 4.2 and exported to SPSS version 25. Bivariable logistic regression followed by multivariable logistic regression was performed. Degree of association between dependent and independent variables had been assessed using adjusted odds ratio with 95% CI at p value of ≤ 0.05. Result From 346 participants in the selected sample 339 (97.9%) of them responded. Prevalence of anemia was 13.3% (n = 45) among which, majority (44.4%) of them had mild anemia, while about (42.2%,) had moderate anemia and around 13.3%, of them were severely anemic. Baseline CD4 count (AOR = 6.58, 95% CI: 2.85–15.22), WHO clinical stage III or IV (AOR = 8.42, 95% CI = 3.47, 20.45), hookworm infection (AOR = 5.06, 95% CI = 2.04, 12) and malaria infection (AOR = 4.92, 95% CI (2.19–11.02) were significantly associated with anemia among children on HAART. Conclusion The prevalence of anemia among participants was relatively low in this study. However, a considerable proportion of participants had moderate to severe anemia. Lower CD4 count at enrolment, advanced HIV clinical stage, malaria and hookworm infection were significantly linked with anemia. Thus, it requires regular monitoring of anemia status in these patients for better clinical outcomes and quality of life improvements.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 28.10.2024
Tilføjet 28.10.2024
Abstract Background The interaction between antibodies and Fc gamma receptors (FcγRs) plays a critical role in regulating immune responses to Plasmodium falciparum. Polymorphisms in genes encoding FcγRs influence the host\'s capacity to control parasite infection. This study investigates whether non-coding variants influencing FcγR expression are associated with anti-malarial immunization and infection traits.Methods We utilized eQTL databases and functional annotations to identify non-coding variants, specifically rs1771575, rs2099684, and rs6700241, within the FCGR gene cluster. In addition, we examined the coding variants rs1801274 (p.His167Arg) and rs1050501 (p.Ile231Thr), which affect the affinity of FcγRIIa and FcγRIIb for IgG. These variants were genotyped in 163 individuals from Burkinabe families. Family-based linear mixed regression and Quantitative Transmission Disequilibrium Tests (QTDT) analyses were performed to assess associations with IgG levels and malaria infection, accounting for relevant covariates.Results Linear mixed models identified rs1771575 as associated with total IgG levels, while both rs1771575 and rs1801274 were linked to IgG2, and rs1050501 to IgG1 levels. A haplotype combining rs2099684 and rs6700241 was positively associated with IgG1. The rs1771575-CC and rs1050501-TT genotypes correlated with higher infection levels in children. QTDT models confirmed the association of rs1771575 with IgG2 and infection in children.Conclusions Our findings suggest that the intergenic variant rs1771575 serves as an independent marker for IgG levels and blood infection in children. This highlights the interplay between regulatory variants and coding mutations in FCGR, which may influence immune function and antibody production. These results underscore the potential for personalized strategies to monitor humoral responses in malaria-endemic regions.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 28.10.2024
Tilføjet 28.10.2024
Abstract Background Children with severe malarial anemia (SMA) typically have low in-hospital mortality but have a high risk of post-discharge readmission or death. We hypothesized that the dysregulation of hematopoiesis, vascular growth factors, and endothelial function that occurs in SMA might affect risk of readmission or death.Methods Plasma was obtained from children 18 months to 12 years old with SMA (N=145) in Kampala, Uganda on admission, and outcomes were assessed over 12-month follow-up. Admission plasma levels of ten biomarkers of vascular growth, hematopoiesis, and endothelial function were compared to risk of readmission or death over 12-month follow-up.Results Over 12-month follow-up, 19 of 145 children with SMA were either readmitted or died: 15 children were readmitted (13 with malaria) and 4 children died. In multivariable analyses adjusted for age and sex, elevated plasma levels of platelet-derived growth factor-BB (PDGF-BB) and vascular endothelial growth factor (VEGF) on admission were independently associated with a decreased risk of all-cause readmission or death (adjusted hazard ratios [95% confidence intervals], 0.28 [0.16-0.51] and 0.19 [0.08-0.48], respectively) and a decreased risk of readmission due to severe malaria (0.27 [0.15, 0.51] and 0.16 [0.05, 0.47]) but not with risk of uncomplicated malaria (1.01 [0.53, 1.95] and 2.07 [0.93-4.64]).Conclusions In children with severe malarial anemia, elevated plasma levels of PDGF-BB and VEGF, two factors that promote angiogenesis, are associated with a decreased risk of readmission or death in the year following admission, primarily driven by a decrease in the risk of recurrent severe malaria.
Læs mere Tjek på PubMedBMC Infectious Diseases, 27.10.2024
Tilføjet 27.10.2024
Abstract Background Anemia is a common complication of HIV infected children and it is enabling HIV disease progression, and decreasing survival. In Ethiopia, there is limited evidence on the prevalence of anemia and its associated factors among HIV infected children particularly in the Awi Zone. Therefore, this study aimed to assess the magnitude and associated factors of anemia among HIV infected children on ART aged from 6 months to 15 year-old in ART Clinic, Awi-Zone, Ethiopia. Objective To assess the magnitude and associated factors of anemia among HIV infected children on antiretroviral therapy in Awi zone health facilities, Northwest, Ethiopia, 2022. Methods A facility based cross-sectional study design was conducted from October to December 2022. A simple random sampling method was used to select the study participants. Descriptive statistics, including frequencies and proportions was used to summarize the study variables and data had been entered in to Epi data 4.2 and exported to SPSS version 25. Bivariable logistic regression followed by multivariable logistic regression was performed. Degree of association between dependent and independent variables had been assessed using adjusted odds ratio with 95% CI at p value of ≤ 0.05. Result From 346 participants in the selected sample 339 (97.9%) of them responded. Prevalence of anemia was 13.3% (n = 45) among which, majority (44.4%) of them had mild anemia, while about (42.2%,) had moderate anemia and around 13.3%, of them were severely anemic. Baseline CD4 count (AOR = 6.58, 95% CI: 2.85–15.22), WHO clinical stage III or IV (AOR = 8.42, 95% CI = 3.47, 20.45), hookworm infection (AOR = 5.06, 95% CI = 2.04, 12) and malaria infection (AOR = 4.92, 95% CI (2.19–11.02) were significantly associated with anemia among children on HAART. Conclusion The prevalence of anemia among participants was relatively low in this study. However, a considerable proportion of participants had moderate to severe anemia. Lower CD4 count at enrolment, advanced HIV clinical stage, malaria and hookworm infection were significantly linked with anemia. Thus, it requires regular monitoring of anemia status in these patients for better clinical outcomes and quality of life improvements.
Læs mere Tjek på PubMedBMC Infectious Diseases, 27.10.2024
Tilføjet 27.10.2024
Abstract Background Anemia is a common complication of HIV infected children and it is enabling HIV disease progression, and decreasing survival. In Ethiopia, there is limited evidence on the prevalence of anemia and its associated factors among HIV infected children particularly in the Awi Zone. Therefore, this study aimed to assess the magnitude and associated factors of anemia among HIV infected children on ART aged from 6 months to 15 year-old in ART Clinic, Awi-Zone, Ethiopia. Objective To assess the magnitude and associated factors of anemia among HIV infected children on antiretroviral therapy in Awi zone health facilities, Northwest, Ethiopia, 2022. Methods A facility based cross-sectional study design was conducted from October to December 2022. A simple random sampling method was used to select the study participants. Descriptive statistics, including frequencies and proportions was used to summarize the study variables and data had been entered in to Epi data 4.2 and exported to SPSS version 25. Bivariable logistic regression followed by multivariable logistic regression was performed. Degree of association between dependent and independent variables had been assessed using adjusted odds ratio with 95% CI at p value of ≤ 0.05. Result From 346 participants in the selected sample 339 (97.9%) of them responded. Prevalence of anemia was 13.3% (n = 45) among which, majority (44.4%) of them had mild anemia, while about (42.2%,) had moderate anemia and around 13.3%, of them were severely anemic. Baseline CD4 count (AOR = 6.58, 95% CI: 2.85–15.22), WHO clinical stage III or IV (AOR = 8.42, 95% CI = 3.47, 20.45), hookworm infection (AOR = 5.06, 95% CI = 2.04, 12) and malaria infection (AOR = 4.92, 95% CI (2.19–11.02) were significantly associated with anemia among children on HAART. Conclusion The prevalence of anemia among participants was relatively low in this study. However, a considerable proportion of participants had moderate to severe anemia. Lower CD4 count at enrolment, advanced HIV clinical stage, malaria and hookworm infection were significantly linked with anemia. Thus, it requires regular monitoring of anemia status in these patients for better clinical outcomes and quality of life improvements.
Læs mere Tjek på PubMedMalaria Journal, 26.10.2024
Tilføjet 26.10.2024
Abstract Background In India, an increase in malaria cases by 21% (223,961 cases) has been reported between 2022 and 2023. Madhya Pradesh ranks 10th in malaria burden, with Mandla district selected for the Malaria Elimination Demonstration Project (MEDP) to demonstrate the feasibility of malaria elimination in a hard-to-reach, tribal-dominated, and hilly forested district. A Constant Contact Community-based Epidemiological Investigation (C3EI) was undertaken by continuous engagement with the community for real-time data collection, mapping of malaria cases, identification of risk factors, and monitoring of intervention outcomes designed to drive effective strategies for malaria elimination. Methods The study mapped 1,143,126 individuals from 248,825 households in the year 2017 in Mandla district for constant contact surveillance. Fortnightly household visits were conducted to inquire about febrile episodes, with on-spot diagnosis and treatment. Data collection was done using the SOCH mobile application, and analysis using R. Results The constant contact household surveillance revealed that out of 956,795 individuals, 230,780 (24.12%) unique individuals reported one or more febrile episodes, with a total of 322,577 febrile episodes and 490 malaria episodes (RDT positive). Males had a higher risk of malaria infection than females (OR = 2.62; p
Læs mere Tjek på PubMedMalaria Journal, 25.10.2024
Tilføjet 25.10.2024
Abstract Background Pulmonary oedema is a feared and difficult to predict complication of severe malaria that can emerge after start of antimalarial treatment. Proinflammatory mediators are thought to play a central role in its pathogenesis. Methods An exploratory study was conducted to evaluate the predictive capacity of biomarkers for development of clinical pulmonary oedema in patients with severe falciparum malaria at two hospitals in Bangladesh. Plasma concentrations of interleukin-6 (IL-6), IL-8, tumour necrosis factor (TNF), soluble Receptor of Advanced Glycation End-products (sRAGE), surfactant protein-D (SP-D), club cell secretory protein (CC16), and Krebs von den Lungen-6 (KL-6) on admission were compared with healthy controls. Correlations between these biomarker and plasma lactate and Plasmodium falciparum histidine-rich protein 2 (PfHRP2) levels were evaluated. Receiver Operating Characteristic (ROC) curves were constructed to assess the predictive capacity for clinical pulmonary oedema of the biomarkers of interest. Results Of 106 screened patients with falciparum malaria, 56 were classified as having severe malaria with a mortality rate of 29%. Nine (16%) patients developed clinical pulmonary oedema after admission. Plasma levels of the biomarkers of interest were higher in patients compared to healthy controls. IL-6, IL-8, TNF, sRAGE, and CC16 levels correlated well with plasma PfHRP2 levels (rs = 0.39; P = 0.004, rs = 0.43; P = 0.001, rs = 0.54; P
Læs mere Tjek på PubMedMalaria Journal, 24.10.2024
Tilføjet 24.10.2024
Abstract Background Attractive targeted sugar baits (ATSBs) have the potential to significantly reduce infective female Anopheles mosquitoes in arid areas, such as in Northern Mali. Malaria is epidemic in the north due to the limited viability of Anopheles species in the desert climate. The goal of this study was to determine of the effect of ATSB on the number of older female An. gambiae and on the number of sporozoite-positive females in villages in northern Mali. Methods Villages were located in the north of Mali. In this study, 5677 ATSB stations were deployed, two on each home, in ten villages during late July and early August 2019. Ten villages served as controls. After a pre-treatment monitoring period in July, An. gambiae populations were monitored again from August to December using CDC-UV light traps, pyrethrum spray catches (PSC), and human landing catches (HLC). Mosquitoes were dissected to estimate their age, while ELISA detected sporozoite positivity. The monthly entomological inoculation rates (EIRs) were calculated for HLC indoors and outdoors. Data from villages were compared using t-tests, while bait station weighted density versus amount of collected females was checked with a Pearson’s correlation. Results A total of 2703 female An. gambiae were caught from treated villages, 4582 from control villages, a 41.0% difference. Dissection of 1759 females showed that ATSB significantly reduced the number of older females. The proportion of older females in treated villages was 0.93% compared to 9.4% in control villages. ELISA analysis of 7285 females showed that bait stations reduced the number of sporozoite-positive females. The infective females in treated villages was 0.30% compared to 2.73% in the controls. The greater the density of bait stations deployed, the fewer the older, infective females (P
Læs mere Tjek på PubMedBMC Infectious Diseases, 22.10.2024
Tilføjet 22.10.2024
Abstract Malaria is a potentially fatal infective illness caused due to parasites that belong to the Plasmodium genus, which are transferred to humans with the help of the stings of affected female Anopheles mosquitoes, and it persists as a serious public wellness problem worldwide. Cordia myxa is a medicinal plant that possesses various medicinal characteristics like antimicrobial, anti-inflammation, antioxidant, and antidiabetic activities, which makes it an important natural resource for the therapy of different maladies in traditional medicine. In this investigation, a certain network pharmacology method has been utilized to identify the potent active components, possible targets as well as signaling pathways present in C. myxa in relation to malaria therapy. The active compounds were submitted to molecular docking approaches to validate their successful activity against the potential targets. The study concluded that three constituents named cosmosiin, stigmastanol, robinetin, and quercetin were highly active and could regulate the expression of Interleukin 6 (IL6) and Cysteine-aspartic acid protease 3 (CASP3), which may act as a potential therapeutic target for malaria treatment. These analyses are validated by molecular dynamics simulation which reflects on the overall structural stability of the intermolecular conformation and interactions. These results can also be witnessed in simulation-based trajectories binding free energies, which concluded the significant role of electrostatic and van der Waals energies in total intermolecular interactions. Finally, we utilized machine learning to predict the anti-malarial activity of C. myxa compounds, comparing them with approved drugs. Using the Chemprop model and MAIP predictions, we assessed ten compounds, revealing their potential as lead anti-malarial agents. This study establishes a groundwork for comprehending the function of the anti-malaria action of C. myxa.
Læs mere Tjek på PubMedPaul Taconet, Barnabas Zogo, Ludovic P. Ahoua Alou, Alphonsine Amanan Koffi, Roch Kounbobr Dabiré, Cedric Pennetier, Nicolas Moiroux
PLoS One Infectious Diseases, 22.10.2024
Tilføjet 22.10.2024
by Paul Taconet, Barnabas Zogo, Ludovic P. Ahoua Alou, Alphonsine Amanan Koffi, Roch Kounbobr Dabiré, Cedric Pennetier, Nicolas Moiroux Background Understanding how weather and landscape shape the fine-scale distribution and diversity of malaria vectors is crucial for efficient and locally tailored vector control. This study examines the meteorological and landscape determinants of (i) the spatiotemporal distribution (presence and abundance) of the major malaria vectors in the rural region of Korhogo (northern Côte d’Ivoire) and (ii) the differences in vector probability of presence, abundance, and diversity observed between that area and another rural West African region located 300 km away in Diébougou, Burkina Faso. Methods We monitored Anopheles human-biting activity in 28 villages of the Korhogo health district for 18 months (2016 to 2018), and extracted fine-scale environmental variables (meteorological and landscape) from high-resolution satellite imagery. We used a state-of-the-art statistical modeling framework to associate these data and identify environmental determinants of the presence and abundance of malaria vectors in the area. We then compared the results of this analysis with those of a similar, previously published study conducted in the Diébougou area. Results The spatiotemporal distribution of malaria vectors in the Korhogo area was highly heterogeneous and appeared to be strongly determined and constrained by meteorological conditions. Rice paddies, temporary sites filled by rainfall, rivers and riparian forests appeared to be the larval habitats of Anopheles mosquitoes. As in Diébougou, meteorological conditions (temperatures, rainfall) appeared to significantly affect all developmental stages of the mosquitoes. Additionally, ligneous savannas were associated with lower abundance of malaria vectors. Anopheles species diversity was lower in Korhogo compared to Diébougou, while biting rates were much higher. Our results suggest that these differences may be due to the more anthropized nature of the Korhogo region in comparison to Diébougou (less forested areas, more agricultural land), supporting the hypothesis of higher malaria vector densities and lower mosquito diversity in more anthropized landscapes in rural West Africa. Conclusion This study offers valuable insights into the landscape and meteorological determinants of the spatiotemporal distribution of malaria vectors in the Korhogo region and, more broadly, in rural west-Africa. The results emphasize the adverse effects of the ongoing landscape anthropization process in the sub-region, including deforestation and agricultural development, on malaria vector control.
Læs mere Tjek på PubMedMalaria Journal, 21.10.2024
Tilføjet 21.10.2024
Abstract Background Long-lasting insecticidal nets (LLINs) have been a widely used malaria prevention method for decades. In South Sudan, LLINs are typically distributed by volunteers who use paper-based systems to collect distribution data. Paper-based systems are simple to use but have a higher occurrence of data inaccuracies and can hinder the timely use of data for decision-making. In 2022, a digital tool was introduced to collect data during the LLIN campaign in Northern Bahr el Ghazal (NBeG). The tool aimed to improve the accuracy of data entry and enable data to be used in real-time for decision making during the campaign. The digital tool was developed with offline functionality and interoperability with DHIS2 tracker version 2.8 in DHIS2 version 2.38. This study assessed the usability of the tool according to user perspectives. Methods A questionnaire containing open- and closed-ended questions was conducted with users of the digital tool, supervisors and other key stakeholders in five counties of NBeG. The questionnaire was administered using Malaria Consortium’s Projects Results System Android mobile application. Usability was determined through a modified and validated System Usability Scale (SUS) approach. Results A total of 93 participants responded to the usability questionnaire. The mean (± standard deviation) usability score across 10 SUS-scoring items was 60.91 (12.87), indicating a modest level of usability. The majority of users agreed the tool was useful for managing the LLIN distribution workflow, was easy to use, reduced workload, and supported stock management and real-time campaign monitoring. There was no significant difference in the usability scores across genders, roles, and counties. Respondents with experience of both paper-based and the digital tool tended to express a preference for the digital tool over paper-based systems. The majority of respondents also reported they would recommend the digital tool to colleagues. Conclusion Digital tools are perceived to improve data collection during LLIN campaigns, even in remote areas where network coverage is challenging. Additional improvements can be implemented to overcome operational challenges and improve usability of the tool. Further study is needed to assess the impact of the digital tool on data quality and real-time data use.
Læs mere Tjek på PubMedMalaria Journal, 20.10.2024
Tilføjet 20.10.2024
Abstract Background Intense pyrethroid resistance threatens the effectiveness of the primary vector control intervention, insecticide-treated nets (ITNs), in Nigeria, the country with the largest malaria burden globally. In this study, the epidemiological and entomological impact of a new type of ITN (piperonyl-butoxide [PBO] ITNs) distributed in Ebonyi State were evaluated. The epidemiological impact was also compared to the impact of standard pyrethroid-only ITNs in Cross River State. Methods A controlled interrupted time series analysis was conducted on monthly malaria incidence data collected at the health facility level, using a multilevel mixed-effects negative binomial model. Data were analysed two years before and after the PBO ITN campaign in Ebonyi State (December 2017 to November 2021). A pre-post analysis, with no comparison group, was used to assess the impact of PBO ITNs on human biting rates and indoor resting density in Ebonyi during the high transmission season immediately before and after the PBO ITN campaign. Results In Ebonyi, PBO ITNs were associated with a 46.7% decrease (95%CI: -51.5, -40.8%; p
Læs mere Tjek på PubMedMalaria Journal, 19.10.2024
Tilføjet 19.10.2024
Abstract Background Submicroscopic Plasmodium infections can be a source of persistent malaria transmission. The aim of this study was to assess their frequency, distribution, morbidity and associated factors in a pre-elimination malaria setting in sub-Saharan Africa, Guinea-Bissau, where the Plasmodium falciparum is the predominant Plasmodium species. Methods Dried fingerprick whole blood samples from 601 participants in the 2017 national, household-based, cross-sectional survey to estimate malaria prevalence were subjected to DNA extraction. The DNA was used in nested end-point PCR assays targeting genus- and species-specific regions of the Plasmodium 18S rRNA genes. Statistical analysis of socio-demographic, clinical and molecular data was carried out using the Statistical Package for the Social Sciences, version 29. Factors associated with submicroscopic P. falciparum infections and their magnitude were sought using Chi-square test and multiple logistic regression models, respectively. Statistically significant level was considered at P-value
Læs mere Tjek på PubMedMalaria Journal, 19.10.2024
Tilføjet 19.10.2024
Abstract Malaria is preventable, but the burden of disease remains high with over 249 million cases and 608,000 deaths reported in 2022. Historically, the most important protective interventions have been vector control and chemopreventive medicines with over 50 million children receiving seasonal malaria chemoprevention in the year 2023. Two vaccines are approved and starting to be deployed, bringing additional protection for children up to 36 months. However, the impact of these currently available tools is somewhat limited on various fronts. Vaccines exhibit partial efficacy, are relatively costly, and not accessible in all settings. The challenges encountered with chemoprevention are barriers to acceptability and feasibility, including frequency of dosing, and the lack of options in the first trimester of pregnancy and for women living with HIV. Also, the emergence of resistance against chemopreventive medicines is concerning. To address these limitations, a target product profile (TPP) is proposed as a road map to guide innovation and to boost the quest for novel chemopreventive alternatives. This TPP describes the ideal product attributes, while acknowledging potential trade-offs that may be needed. Critically, it considers the target populations most at risk; primarily infants, children, and pregnant women. Malaria control and elimination requires appropriate chemoprevention, not only in areas of high endemicity and transmission, but also in lower transmission areas where immunity is declining, as well as for travellers from areas where malaria has been eliminated. New medicines should show acceptable safety and tolerability, with high and long protective efficacy. Formulations and costs need to support operational adherence, access, and effectiveness. Next generation long-acting oral and injectable drugs are likely to constitute the backbone of malaria prevention. Therefore, the perspectives of front-line experts in malaria prevention, researchers, and those involved in drug development are captured in the TPP. This inclusive approach aims at concentrating efforts and aligning responses across the community to develop new and transformative medicines.
Læs mere Tjek på PubMedMalaria Journal, 19.10.2024
Tilføjet 19.10.2024
Abstract Background Peru is a low-endemic transmission area for malaria, where the majority (84%) of incident malaria cases are localized to the department of Loreto, which is composed of several geographically isolated rural communities. Recent intervention efforts targeting at-risk Indigenous populations that live in riverine communities in Loreto place emphasis on preventive behaviours to decrease transmission. However, malaria related behaviour change is often dependent upon local knowledge, beliefs, and practices, especially in areas where malaria is viewed an embedded and unavoidable aspect of life. Methods This exploratory case study used semi-structured interviews conducted in Spanish between February and March of 2019 to examine the knowledge, attitudes, and practices related to malaria prevention among the Indigenous Maijuna people of Sucusari, Loreto, Peru. Participants who consented were also administered a rapid diagnostic test (RDT) upon the time of interview. Results A total of 33 community members were interviewed, and 31 were tested via malaria rapid diagnostic tests, with RDT filter paper subsequently tested using PCR. All test results were negative for malaria. Themes that emerged included: varying knowledge of methods to prevent malaria, reports of observed changes in malaria incidence over time, confusion surrounding malaria transmission, treatment-seeking as a common behaviour, the belief that medications are effective, and the acceptance of bed nets which were viewed as a lifestyle norm. Conclusion These shared narratives should be used as a foundation for further studies and health interventions among communities in the Peruvian Amazon with limited access to health services where culturally resonant, community-based health programming is essential to improving health. Takeaways regarding confusion surrounding malaria transmission should also be considered.
Læs mere Tjek på PubMedChew, R., Wynberg, E., Liverani, M., Rekol, H., Nguon, C., Dysoley, L., Vanna, M., Callery, J. J., Mishra, A., Adhikari, B., Tripura, R., Chandna, A., Fegan, G., Waithira, N., Maude, R. J., Day, N. P. J., Peto, T. J., Lubell, Y.
BMJ Open, 19.10.2024
Tilføjet 19.10.2024
IntroductionAcute febrile illness (AFI), traditionally attributed to malaria, is a common reason for seeking primary healthcare in rural South and Southeast Asia. However, malaria transmission has declined while health workers are often poorly equipped to manage non-malarial AFIs. This results in indiscriminate antibiotic prescribing and care escalation, which promotes antibiotic resistance and may increase healthcare costs. To address this problem, an electronic clinical decision support algorithm (eCDSA) called ‘Electronic clinical Decision support for Acute fever Management (EDAM)’ has been developed for primary health workers which integrates clinical, epidemiological and vital sign data with simple point-of-care tests to produce a diagnosis and management plan. Methods and analysisThis is a pragmatic cluster-randomised trial aiming to assess the effect of EDAM and related training on antibiotic prescribing rates in rural Cambodian primary health centres (PHCs) as the primary outcome, along with a range of secondary outcomes including safety. Patients with AFI are eligible for recruitment if they are aged ≥1 year. A cluster is defined as a PHC and PHCs will be randomised to control (standard of care) and intervention (EDAM and associated training) arms, with 15 PHCs per arm. Patients will be followed up after 7 days to ascertain the safety profile of EDAM. Each PHC will recruit 152 patients (total 4560), based on a baseline antibiotic prescription rate of 25% and expected reduction to 17.5% with EDAM. Ethics and disseminationResults will be published in international peer-reviewed journals to inform the design of future versions of EDAM and of future trials of similar eCDSAs and other digital health interventions targeted towards rural populations. This study was approved by the Oxford University Tropical Research Ethics Committee (550-23) and the Cambodian National Ethics Committee for Health Research (395-NECHR). Trial registration numberInternational Standard Randomized Controlled Trial Number Registry (ISRCTN15157105).
Læs mere Tjek på PubMedBMC Infectious Diseases, 19.10.2024
Tilføjet 19.10.2024
Abstract Malaria is a potentially fatal infective illness caused due to parasites that belong to the Plasmodium genus, which are transferred to humans with the help of the stings of affected female Anopheles mosquitoes, and it persists as a serious public wellness problem worldwide. Cordia myxa is a medicinal plant that possesses various medicinal characteristics like antimicrobial, anti-inflammation, antioxidant, and antidiabetic activities, which makes it an important natural resource for the therapy of different maladies in traditional medicine. In this investigation, a certain network pharmacology method has been utilized to identify the potent active components, possible targets as well as signaling pathways present in C. myxa in relation to malaria therapy. The active compounds were submitted to molecular docking approaches to validate their successful activity against the potential targets. The study concluded that three constituents named cosmosiin, stigmastanol, robinetin, and quercetin were highly active and could regulate the expression of Interleukin 6 (IL6) and Cysteine-aspartic acid protease 3 (CASP3), which may act as a potential therapeutic target for malaria treatment. These analyses are validated by molecular dynamics simulation which reflects on the overall structural stability of the intermolecular conformation and interactions. These results can also be witnessed in simulation-based trajectories binding free energies, which concluded the significant role of electrostatic and van der Waals energies in total intermolecular interactions. Finally, we utilized machine learning to predict the anti-malarial activity of C. myxa compounds, comparing them with approved drugs. Using the Chemprop model and MAIP predictions, we assessed ten compounds, revealing their potential as lead anti-malarial agents. This study establishes a groundwork for comprehending the function of the anti-malaria action of C. myxa.
Læs mere Tjek på PubMedMalaria Journal, 18.10.2024
Tilføjet 18.10.2024
Abstract Background Despite the application of various tools for the control of vectors of Plasmodium falciparum, malaria remains the major killer disease in sub-Saharan Africa accounting for up to 90% of deaths due to the disease. Due to limitations of the useage of chemical insecticides such as resistance, negative impact on the environment and to nontarget organisms, the World Health Organization (WHO) requires that affected countries find alternative vector control tools. This study evaluated the effectiveness of ( +)-usnic acid (UA) as an insecticide through oral administration to male and female Anopheles gambiae as an alternative or additional active ingredient to be used in toxic sugar bait. Methods ( +)-usnic acid was diluted using acetone at 5, 10, and 15 mg/ml concentrations in three replicates. A 5 ml mixture of 2% food dye and 10% sugar using chlorine-free water mixed with the dilutions of the ( +)-usnic acid and negative control was made containing 2% food dye and 10% sugar solution. The preparations were soaked on a ball of cotton wool and placed over the net of a cup. 5 male and 5 non-blood-fed female newly hatched starved An. gambiae Kisumu strain were introduced together into a cup and monitored for knockdown and mortalities after 4, 24 48, and 72 h. The data were analysed using a multiple linear regression model using the lm function, a base R function and a posthoc test were conducted on the significant main effects and interaction terms using the emmeans function from the emmeans R package. All analyses were performed in RStudio using base R (version 4.3.3). Results There was high mortality of both male and female An. gambiae after ingestion of the toxic sugar bait. 15 mg/ml usnic acid caused the highest mortality (50%) within the first 4 h compared to 5 and 10 mg/ml ( +)-UA. There was a decline in the mortality rate with increased exposure time from 24 to 72 h, however, there was a significant difference in mortality at 5, 10 and 15 mg/ml. Acute toxicity was associated with ingestion of 15 mg/ml after 24 h. 72 h post-mortality was lower in all concentrations than in the control. High mortality was observed among females over the first 4 h (60%) compared to males (40%) due to higher feeding rate of the toxic agent. The proportion of dead males and females was equal after 24 h while after 48 h, the proportion of dead males was high.There was a significantly lower mortality rate after 72 h for both males and females (0 to 13.3%). Compared to all the treatments, high mortality of males was observed. Conclusions The results of this study indicate that ( +)-UA when administered as oral sugar bait to An. gambiae has insecticidal properties and is a suitable ingredient to be used as a toxic agent in the novel attractive toxic sugar bait for the control of malaria vectors. ( +)-UA may be an alternative active ingredient as toxic bait in the effort to reduce and eliminate the transmission of Plasmodium falciparum in Africa.
Læs mere Tjek på PubMedMalaria Journal, 18.10.2024
Tilføjet 18.10.2024
Abstract Background Malaria is an infectious disease caused by the Plasmodium species and is a global burden. When not treated correctly, it can reemerge as a relapse or recrudescence. Malaria relapse cases can contribute to maintaining active transmission chains and can influence the patient to develop severe malaria, potentially leading to hospitalization or death. The objective of this study is to estimate the number of malaria relapse cases in the extra-Amazon region of Brazil and to investigate the associated factors. Methods This is a case–control study that analyses malaria infections caused by Plasmodium vivax, as reported in Notifiable Diseases Information System (Sinan) for the Brazilian extra-Amazon region (an area not endemic for the disease) from 2008 to 2019. For the identification of relapse cases, deduplication record linkage processes in R software were used. Malaria relapses were defined as the case group, and new malaria infections were defined as the control group. Logistic regression models were used to assess associated factors. Results Of the 711 malaria relapses, 589 (82.8%) were first relapses. Most relapses (71.6%) occurred between 30 and 120 days after the previous infection. Malaria relapses are spread throughout the extra-Amazon region, with a higher concentration near big cities. Driver occupation was found to be a common risk factor compared to other occupations, along with asymptomatic individuals. Other associated factors were: being infected in the Brazilian Amazon region, having follow-ups for malaria relapses, and having parasite density of the previous infection higher than 10,000 parasites per mm3. Conclusions This study provides evidence that allows malaria health surveillance services to direct their efforts to monitor cases of malaria in the highest risk segments identified in this study, particularly in the period between 30 and 120 days after being infected and treated. Relapses were associated to driver occupation, absence of symptoms, infection in endemic areas of Brazil, being detected through active surveillance or routine follow-up actions, and with parasitaemia greater than 10,000 parasites per mm3 in the previous infection. Improving cases follow-up is essential for preventing relapses.
Læs mere Tjek på PubMedHabtu Debash, Ermiyas Alemayehu, Melaku Ashagrie Belete, Hussen Ebrahim, Ousman Mohammed, Daniel Gebretsadik, Mihret Tilahun, Agumas Shibabaw, Zewudu Mulatie, Bruktawit Eshetu, Saba Gebremichael, Alemu Gedefie
PLoS One Infectious Diseases, 18.10.2024
Tilføjet 18.10.2024
by Habtu Debash, Ermiyas Alemayehu, Melaku Ashagrie Belete, Hussen Ebrahim, Ousman Mohammed, Daniel Gebretsadik, Mihret Tilahun, Agumas Shibabaw, Zewudu Mulatie, Bruktawit Eshetu, Saba Gebremichael, Alemu Gedefie Background Malaria and undernutrition pose challenges for children in conflict-affected areas. Understanding the prevalence and risk factors for these issues in war-torn communities is important to effectively design aid efforts and select interventions. This study aimed to determine the prevalence and correlates of malaria and undernutrition among febrile children in northeast Ethiopia to help address these problems. Methods A cross-sectional study was conducted from November 2022 to January 2023. Four hundred twenty-two children were enrolled using a systematic random sampling technique. Data on associated factor variables were collected via questionnaire. Capillary blood samples were collected from each child to prepare thick and thin blood films, which were stained with Giemsa and examined microscopically. Height and weight measurements were also taken using a meter and a standard calibrated balance. The data were analyzed in SPSS 26.0 using bivariable and multivariable logistic regression to determine associations between correlates, malaria infection, and undernutrition. Statistical significance was set at p < 0.05. Results The overall malaria prevalence among screened children at temporary sites in the conflict-affected areas of Northeast Ethiopia was 65.9% (278/422). Plasmodium falciparum, P. vivax, and mixed infections accounted for 74.1%, 19.8%, and 6.1% of the cases, respectively. The presence of stagnant water (P
Læs mere Tjek på PubMedMalaria Journal, 17.10.2024
Tilføjet 17.10.2024
Abstract Background Malaria in pregnancy (MiP) is a public health concern especially for pregnant women living in slums. The World Health Organization recommends at least three doses of Sulfadoxine-Pyrimethamine (SP) to prevent MiP. In Ghana, it is recommended that pregnant women receive a minimum of five doses of the medication. This study sought to determine the level of adherence to IPT5 policy and factors associated with adherence among pregnant women in a slum community in Ghana. Methods This was a cross-sectional study involving 232 nursing mothers and four healthcare workers at the St. Martin’s Memorial Hospital, Sukura, Ghana. Sociodemographic characteristics of nursing mothers were obtained using an interview-administered questionnaire. Data on the number of SP doses and other obstetrics characteristics were collected by reviewing the antenatal record books. To obtain information about healthcare and health system factors associated with adherence to the five-dose policy, four healthcare providers were interviewed. A data extraction form was used to obtain information about the availability of SP at the facility. Results The level of adherence to IPT5 was 8.6% (20/232) (95% CI 5.0–12.3) among the participants. Only 8.4% of the participants received their first dose at 16 weeks. Respondents who began ANC in the second trimester were 81% less likely to adhere to IPT5 than those who began in the first trimester (aOR = 0.19, 95% CI 90.01–0.65, p
Læs mere Tjek på PubMedBMC Infectious Diseases, 17.10.2024
Tilføjet 17.10.2024
Abstract Background Malaria remains a significant public health concern, especially for the deadliest parasite, Plasmodium falciparum. During acute malaria, various cytokines, including osteopontin (OPN), regulate the immune response. OPN has been shown to be protective against malaria in mice. Nonetheless, its precise function and potential ability to control parasites during acute malaria in humans remain poorly understood. Results Blood samples were collected from Swedish adults with imported malaria, Ugandan children and adults with symptomatic malaria (including follow-up after 42 days), Ugandans with non-malarial fever and healthy individuals from both Uganda and Sweden. Parasitemia was determined by microscopy. Malaria-negative samples were verified by LAMP. OPN and interferon-γ (IFN- γ) levels were measured using ELISA. In children, OPN levels were significantly higher during acute infection compared to levels after 42 days, whereas Ugandan adults showed no difference. Swedish adults with imported malaria had elevated OPN levels compared to both Swedish controls and Ugandan adults with malaria. Parasitemia was significantly correlated with both OPN and IFN-γ levels across the entire cohort. While a significant correlation between OPN and IFN-γ was evident overall, it remained statistically significant only in Ugandan adults when analyzed by subgroups. This suggests that OPN is not just a general marker of inflammation but may be regulated differently during the development of malaria immunity. Conclusions In acute malaria, elevated OPN levels showed a stronger correlation with lack of immunity than age. These findings underscore the potential importance of OPN in malaria, particularly in non-immune individuals.
Læs mere Tjek på PubMedJulia Zerebinski, David F. Plaza
Trends in Parasitology, 17.10.2024
Tilføjet 17.10.2024
Recent studies by Girgis et al. and de Cesare et al. promise to advance malaria genomic surveillance using inexpensive and portable long-read amplicon-sequencing technologies. These technologies allow rapid characterization of drug-resistance markers, antigenic diversity, and diagnostic target loci from dried blood spots, providing new tools for surveillance in endemic regions and informing interventions to combat malaria more effectively.
Læs mere Tjek på PubMedRitwik Singhal, Isadora O. Prata, Victoria A. Bonnell, Manuel Llinás
Trends in Parasitology, 17.10.2024
Tilføjet 17.10.2024
The regulation of gene expression in Plasmodium spp., the causative agents of malaria, relies on precise transcriptional control. Malaria parasites encode a limited repertoire of sequence-specific transcriptional regulators dominated by the apicomplexan APETALA 2 (ApiAP2) protein family. ApiAP2 DNA-binding proteins play critical roles at all stages of the parasite life cycle. Recent studies have provided mechanistic insight into the functional roles of many ApiAP2 proteins. Two major areas that have advanced significantly are the identification of ApiAP2-containing protein complexes and the role of ApiAP2 proteins in malaria parasite sexual development. In this review, we present recent advances on the functional biology of ApiAP2 proteins and their role in regulating gene expression across the blood stages of the parasite life cycle.
Læs mere Tjek på PubMedMalaria Journal, 16.10.2024
Tilføjet 16.10.2024
Abstract Background Non-inferiority trials are recommended by the World Health Organization (WHO) to demonstrate that health products show comparable efficacy to that of existing standard of care. As part of the WHO Global Malaria Programme (GMP) process of assessment of malaria vector control products, a second-in-class insecticide-treated net (ITN) must be shown to be non-inferior to a first-in-class product based on mosquito mortality. The public health impact of the first-in-class pyrethroid-piperonyl butoxide (PBO) ITN, Olyset® Plus, has been demonstrated in epidemiological trials in areas with insecticide-resistant mosquitoes, but there is a need to determine the efficacy of other pyrethroid-PBO nets to ensure timely market availability of nets in order to increase access to ITNs. The non-inferiority of a deltamethrin-PBO ITN Yorkool® G3 was evaluated entomologically against Olyset® Plus in experimental huts in Tanzania, following WHO guidelines for non-inferiority trials. Methods The trial of the two pyrethroid-PBO ITNs was conducted in experimental huts in Lupiro, Tanzania, using a randomized 7 × 7 Latin square block design. The study ran for 49 nights in 14 huts assessing the mosquito mortality and blood-feeding of wild, free-flying, pyrethroid-resistant Anopheles arabiensis. Using the non-inferiority approach, the comparative efficacy (primary endpoint was mosquito mortality at 24 h and secondary endpoint was blood-feeding) of unwashed and 20 times field-washed pyrethroid-PBO Yorkool® G3 ITNs, were compared with the first-in-class product Olyset® Plus and against a pyrethroid-only ITN, PermaNet® 2.0 ITNs, as a standard comparator. Results The experimental hut trial demonstrated non-inferiority and superiority of Yorkool® G3 to Olyset® Plus based on mosquito mortality [51% vs. 39%, OR 1.68 (95% CI 1.50–1.88)], given that lower 95% CI exceeded 0.74 (delta of 39%) and the margin of no difference (1). Blood-feeding inhibition was high for all treated ITNs (> 90%) and Yorkool® G3 was non-inferior to Olyset® Plus [4% vs. 2%, OR 1.81 (95% CI 1.46–2.39)], given that upper 95% CI was less than 4.85 (delta of 4%). The pyrethroid-PBO ITNs were superior to the pyrethroid-only net, PermaNet® 2.0, as determined by both the proportion of mortality and blood-feeding of mosquitoes (p-value
Læs mere Tjek på PubMedBMC Infectious Diseases, 16.10.2024
Tilføjet 16.10.2024
Abstract Background Malaria remains a significant public health concern, especially for the deadliest parasite, Plasmodium falciparum. During acute malaria, various cytokines, including osteopontin (OPN), regulate the immune response. OPN has been shown to be protective against malaria in mice. Nonetheless, its precise function and potential ability to control parasites during acute malaria in humans remain poorly understood. Results Blood samples were collected from Swedish adults with imported malaria, Ugandan children and adults with symptomatic malaria (including follow-up after 42 days), Ugandans with non-malarial fever and healthy individuals from both Uganda and Sweden. Parasitemia was determined by microscopy. Malaria-negative samples were verified by LAMP. OPN and interferon-γ (IFN- γ) levels were measured using ELISA. In children, OPN levels were significantly higher during acute infection compared to levels after 42 days, whereas Ugandan adults showed no difference. Swedish adults with imported malaria had elevated OPN levels compared to both Swedish controls and Ugandan adults with malaria. Parasitemia was significantly correlated with both OPN and IFN-γ levels across the entire cohort. While a significant correlation between OPN and IFN-γ was evident overall, it remained statistically significant only in Ugandan adults when analyzed by subgroups. This suggests that OPN is not just a general marker of inflammation but may be regulated differently during the development of malaria immunity. Conclusions In acute malaria, elevated OPN levels showed a stronger correlation with lack of immunity than age. These findings underscore the potential importance of OPN in malaria, particularly in non-immune individuals.
Læs mere Tjek på PubMedN. J. WhiteK. Chotivanich1Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand2Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom3Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, ThailandFerric C. FangSunil Parikh
Clinical Microbiology Reviews, 16.10.2024
Tilføjet 16.10.2024
Malaria Journal, 16.10.2024
Tilføjet 16.10.2024
Abstract Malaria parasites are haploid within humans, but infections often contain genetically distinct groups of clonal parasites. When the per-infection number of genetically distinct clones (i.e., the multiplicity of infection, MOI) exceeds one, and per-infection genetic data are generated in bulk, important information are obfuscated. For example, the MOI, the phases of the haploid genotypes of genetically distinct clones (i.e., how the alleles concatenate into sequences), and their frequencies. This complicates many downstream analyses, including relatedness estimation. MOIs, parasite sequences, their frequencies, and degrees of relatedness are used ubiquitously in malaria studies: for example, to monitor anti-malarial drug resistance and to track changes in transmission. In this article, MrsFreqPhase methods designed to estimate statistically malaria parasite MOI, relatedness, frequency and phase are reviewed. An overview, a historical account of the literature, and a statistical description of contemporary software is provided for each method class. The article ends with a look towards future method development, needed to make best use of new data types generated by cutting-edge malaria studies reliant on MrsFreqPhase methods.
Læs mere Tjek på PubMedMalaria Journal, 16.10.2024
Tilføjet 16.10.2024
Abstract Background Healthcare providers (HCPs) practice and correct management of suspected malaria (CMSM) are central components of malaria elimination and prevention of re-establishment (POR) in countries in the elimination phase. However, knowledge of malaria surveillance systems and HCPs practices often wanes in countries aiming to eliminate malaria due to the low numbers of cases. The study aimed to implement a valid Simulated Malaria Online Tool (SMOT) for assessment HCP performance in CMSM and POR in a malaria-free area. Methods HCPs were evaluated using SMOT tool based on four criteria including presenting a suspected malaria case for detection of HCPs’ failures in recognition (a), diagnosis (b), appropriate treatment (c), and urgent reporting (d); and compared with simulated patients (SP). Multiple logistic regression analysis was carried out to estimate adjusted odds ratios (ORs) for the risk of HCPs failures. Results The overall failure proportion was 237 (83%), and the majority of failures were in recognition (a). There was no significant difference between the SMOT and SP based on all failure criteria (P > 0.05). The private clinic (93%) and the public specialized clinic (70%) had the highest and lowest failure proportions. After passing the recognition stage (a), the overall failure proportions decreased to 47.8% and 25.0% for total HCPs and infectious disease specialists, respectively. In the final analysis, private sector (AOR = 4.36: 1.25–15.2), not-specialist providers (AOR = 2.84: 1.29–6.25) and HCPs with ≥ 5 years’ experience (AOR = 2.03: 1.01–6.25) increased the risk of failure. Conclusion Findings confirmed the implementation of SMOT tool in settings where malaria transmission is low or interrupted. The tool is able to identify sub-groups of providers needing strengthening, and contributes to the prevention of malaria re-establishment.
Læs mere Tjek på PubMedJournal of the American Medical Association, 15.10.2024
Tilføjet 15.10.2024
Journal of the American Medical Association, 15.10.2024
Tilføjet 15.10.2024
This quasi-experimental study evaluates the association between the distribution of rapid diagnostic tests for malaria and the management of febrile illness and mortality among children younger than 5 years of age in sub-Saharan African countries.
Læs mere Tjek på PubMedBMC Infectious Diseases, 12.10.2024
Tilføjet 12.10.2024
Abstract Background Human Immunodeficiency Virus (HIV) and malaria are two major diseases in sub-Saharan Africa. Co-infection can significantly impact the clinical outcomes of both conditions. We assessed the proportion of HIV-infected children at Korle Bu Teaching Hospital (KBTH) and Princess Marie Louise Hospital (PML) with malaria parasites. The association between asymptomatic malaria parasitaemia and virological non-suppression was also determined in these children. Methods This cross-sectional study of 277 asymptomatic malaria in children receiving care at paediatric HIV clinics at KBTH and PML was conducted from September to November 2022. Patients who had been on antiretroviral therapy (ART) for at least six months were eligible to participate. Structured questionnaires were used to collect socio-demographic information, malaria prevention behaviors, and ART-related data using in-person interviews. Microscopy and PCR were used to screen for malaria, and GeneXpert was used to determine viral load. To examine the determinants of malaria PCR positivity and virological non-suppression, chi-square tests and logistic regression were performed. Results The median age of the participants was 9 years (range: 6–12 years). Males comprised 158 (57%) of the study population. We detected 10 (3.6%) and 21 (7.6%) malaria cases by microscopy and PCR, respectively. Virological non-suppression (VL > 1000 copies/ml) was observed in 82 (29.6%) of the 277 participants. Among the suppressed individuals, 62 (22.4%) exhibited low-level viraemia (VL level 40-1000 copies/ml) and 133 (48%) had undetectable viral load levels. No factors were associated with the presence of malaria PCR positivity carriage. Poor adherence to ART was associated with a five-fold increase in the risk of viral load non-suppression (AOR = 4.89 [CI = 2.00-11.98], p = 0.001). Conclusion The proportion of children living with HIV with asymptomatic malaria parasitaemia was low. Approximately one-third of the study population had virological non-suppression. The interaction between malaria parasitemia and viral replication may not be the main cause for virological non-suppression in this low transmission area.
Læs mere Tjek på PubMedPaula Tesine, Sze-Ann Woon, Moses Laman, Gumul Yadi, Phantica Yambo, Bernadine Kasian, Lina Lorry, Leanne J. Robinson, Sam Salman, Kevin T. Batty, William Pomat, Laurens Manning, Wendy A. Davis, Timothy M.E. Davis, Brioni R Moore
International Journal of Infectious Diseases, 12.10.2024
Tilføjet 12.10.2024
A range of management strategies have been developed to counter the adverse maternal and foetal outcomes associated with malaria in pregnancy [1]. These include prompt treatment of symptomatic infections, and intermittent preventive treatment in pregnancy (IPTp) which commonly comprises monthly sulfadoxine-pyrimethamine [2]. Optimal postpartum management is, however, less clear despite epidemiological evidence that women in endemic areas remain vulnerable after delivery. The overall risk of malaria declines during the postpartum period but several studies have shown it does not reach that of non-pregnant women from the same community [3-5], while the incidence of vivax malaria during this period may be higher than that during pregnancy [6].
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Climatic conditions are a key determinant of malaria transmission intensity, through their impacts on both the parasite and its mosquito vectors. Mathematical models relating climatic conditions to malaria transmission can be used to develop spatial maps of climatic suitability for malaria. These maps underpin efforts to quantify the distribution and burden of malaria in humans, enabling improved monitoring and control. Previous work has developed mathematical models and global maps for the suitability of temperature for malaria transmission. In this paper, existing temperature-based models are extended to include two other important bioclimatic factors: humidity and rainfall. This model is combined with fine spatial resolution climatic data to produce a more biologically-realistic global map of climatic suitability for Plasmodium falciparum malaria. The climatic suitability index developed corresponds more closely than previous temperature suitability indices with the global distribution of P. falciparum malaria. There is weak agreement between the Malaria Atlas Project estimates of P. falciparum prevalence in Africa and the estimates of suitability solely based on temperature (Spearman Correlation coefficient of (rho = 0.24) ). The addition of humidity and then rainfall improves the comparison ( (rho = 0.62) when humidity added; (rho =0.70) when both humidity and rainfall added). By incorporating the impacts of humidity and rainfall, this model identifies arid regions that are not climatically suitable for transmission of P. falciparum malaria. Incorporation of this improved index of climatic suitability into geospatial models can improve global estimates of malaria prevalence and transmission intensity.
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Climatic conditions are a key determinant of malaria transmission intensity, through their impacts on both the parasite and its mosquito vectors. Mathematical models relating climatic conditions to malaria transmission can be used to develop spatial maps of climatic suitability for malaria. These maps underpin efforts to quantify the distribution and burden of malaria in humans, enabling improved monitoring and control. Previous work has developed mathematical models and global maps for the suitability of temperature for malaria transmission. In this paper, existing temperature-based models are extended to include two other important bioclimatic factors: humidity and rainfall. This model is combined with fine spatial resolution climatic data to produce a more biologically-realistic global map of climatic suitability for Plasmodium falciparum malaria. The climatic suitability index developed corresponds more closely than previous temperature suitability indices with the global distribution of P. falciparum malaria. There is weak agreement between the Malaria Atlas Project estimates of P. falciparum prevalence in Africa and the estimates of suitability solely based on temperature (Spearman Correlation coefficient of (rho = 0.24) ). The addition of humidity and then rainfall improves the comparison ( (rho = 0.62) when humidity added; (rho =0.70) when both humidity and rainfall added). By incorporating the impacts of humidity and rainfall, this model identifies arid regions that are not climatically suitable for transmission of P. falciparum malaria. Incorporation of this improved index of climatic suitability into geospatial models can improve global estimates of malaria prevalence and transmission intensity.
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Background The RTS,S malaria vaccine has been prequalified for use in endemic settings prioritizing areas with moderate to high disease transmission. The impact of a vaccine at the population level may differ from observations during clinical trial due to programmatic, and individual-related factors, among others. The objective of this study was to assess the impact of the RTS,S malaria vaccine on uncomplicated malaria among children aged 12–59 months in the Phase IV study districts, Upper East Region, Ghana. Methods A retrospective study was conducted using routine malaria surveillance data for the period 2020–2022. The burden of uncomplicated malaria was compared between the implementing (Kasena Nankana East and West districts) and comparator areas (Builsa North and South districts). The impact of RTS,S malaria vaccine was assessed by estimating the percentage reduction in uncomplicated malaria and incidence averted in the implementing area, accounting for the effect of confounders. Results Over 50,000 episodes of uncomplicated malaria among children aged 12–59 months were included in the study. Uncomplicated malaria was reduced by 33% (95%CI 29–36) over the entire study period, but the malaria incidence averted declined from 324/1,000 (95% CI 298–339; p
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Background The RTS,S malaria vaccine has been prequalified for use in endemic settings prioritizing areas with moderate to high disease transmission. The impact of a vaccine at the population level may differ from observations during clinical trial due to programmatic, and individual-related factors, among others. The objective of this study was to assess the impact of the RTS,S malaria vaccine on uncomplicated malaria among children aged 12–59 months in the Phase IV study districts, Upper East Region, Ghana. Methods A retrospective study was conducted using routine malaria surveillance data for the period 2020–2022. The burden of uncomplicated malaria was compared between the implementing (Kasena Nankana East and West districts) and comparator areas (Builsa North and South districts). The impact of RTS,S malaria vaccine was assessed by estimating the percentage reduction in uncomplicated malaria and incidence averted in the implementing area, accounting for the effect of confounders. Results Over 50,000 episodes of uncomplicated malaria among children aged 12–59 months were included in the study. Uncomplicated malaria was reduced by 33% (95%CI 29–36) over the entire study period, but the malaria incidence averted declined from 324/1,000 (95% CI 298–339; p
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Background Malaria prevention and control strategies have been hampered by urbanization and the spread of Anopheles stephensi. The spread of this vector into Africa further complicates the already complex malaria situation, that could put about 126 million Africans at risk of infection. Hence, this study aimed to assess the determinants of urban malaria, focusing on the role of urbanization and the distribution of An. stephensi in Eastern Ethiopia. Methods A matched case control study was conducted among febrile urban residents of Dire Dawa (malaria positive as cases and negative as a control). A capillary blood sample was collected for parasite identification using microscopic examination and an interviewer administered questionnaire was used to collect additional data. Centers for Disease Control and Prevention miniature light traps (CDC-LT) and Prokopack aspirator were used to collect adult mosquito vectors from the selected cases and control houses to identify the mosquito vector species. Then, the data were exported to STATA for analysis. Conditional logistic regression was done to identify determinants, and principal component Analysis (PCA) was done for some independent variables. Results This study enrolled 132 cases and 264 controls from urban setting only. Of the 132 cases, 90 cases were positive for Plasmodium falciparum, 34 were positive for Plasmodium vivax and 8 had mixed infections. All cases and controls were similar with regard to their respective age and sex. Travel history (AOR: 13.1, 95% CI 2.8–61.4), presence of eves and holes on walls (AOR: 2.84, 95% CI 1.5–5.5), history of malaria diagnosis (AOR: 2.4, 95% CI 1.1–5.3), owning any livestock (AOR: 7.5, 95% CI 2.4–22.8), presence of stagnant water in the area (AOR: 3.2, 95% CI 1.7–6.1), sleeping under bed net the previous night (AOR: 0.21, 95% CI 0.1–0.6) and knowledge on malaria and its prevention (AOR: 2.2, 95% CI 1.2–4.1) were determinants of urban malaria infection. About 34 adult Anopheles mosquitoes were collected and identified from those selected cases and control houses and 27 of them were identified as An. stephensi. Conclusion Among the cases, the dominant species were P. falciparum. This study identified travel history, house condition, past infection, livestock ownership, stagnant water, bed net use, and malaria knowledge as determinants of infection. This study also found the dominance of the presence of An. stephensi among the collected mosquito vectors. This suggests that the spread of An. stephensi may be impacting malaria infection in the study area. Hence, strengthening urban-targeted malaria interventions should be enhanced to prevent and control further urban malaria infection and spread.
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Background Malaria prevention and control strategies have been hampered by urbanization and the spread of Anopheles stephensi. The spread of this vector into Africa further complicates the already complex malaria situation, that could put about 126 million Africans at risk of infection. Hence, this study aimed to assess the determinants of urban malaria, focusing on the role of urbanization and the distribution of An. stephensi in Eastern Ethiopia. Methods A matched case control study was conducted among febrile urban residents of Dire Dawa (malaria positive as cases and negative as a control). A capillary blood sample was collected for parasite identification using microscopic examination and an interviewer administered questionnaire was used to collect additional data. Centers for Disease Control and Prevention miniature light traps (CDC-LT) and Prokopack aspirator were used to collect adult mosquito vectors from the selected cases and control houses to identify the mosquito vector species. Then, the data were exported to STATA for analysis. Conditional logistic regression was done to identify determinants, and principal component Analysis (PCA) was done for some independent variables. Results This study enrolled 132 cases and 264 controls from urban setting only. Of the 132 cases, 90 cases were positive for Plasmodium falciparum, 34 were positive for Plasmodium vivax and 8 had mixed infections. All cases and controls were similar with regard to their respective age and sex. Travel history (AOR: 13.1, 95% CI 2.8–61.4), presence of eves and holes on walls (AOR: 2.84, 95% CI 1.5–5.5), history of malaria diagnosis (AOR: 2.4, 95% CI 1.1–5.3), owning any livestock (AOR: 7.5, 95% CI 2.4–22.8), presence of stagnant water in the area (AOR: 3.2, 95% CI 1.7–6.1), sleeping under bed net the previous night (AOR: 0.21, 95% CI 0.1–0.6) and knowledge on malaria and its prevention (AOR: 2.2, 95% CI 1.2–4.1) were determinants of urban malaria infection. About 34 adult Anopheles mosquitoes were collected and identified from those selected cases and control houses and 27 of them were identified as An. stephensi. Conclusion Among the cases, the dominant species were P. falciparum. This study identified travel history, house condition, past infection, livestock ownership, stagnant water, bed net use, and malaria knowledge as determinants of infection. This study also found the dominance of the presence of An. stephensi among the collected mosquito vectors. This suggests that the spread of An. stephensi may be impacting malaria infection in the study area. Hence, strengthening urban-targeted malaria interventions should be enhanced to prevent and control further urban malaria infection and spread.
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Background Malaria affects children under the age of five and pregnant women, leading to high morbidity and mortality rates. In sub-Saharan Africa, Patent and Proprietary Medicine Vendors (PPMVs) have been identified as key players in the provision of malaria treatment due to their accessibility and availability in communities, but PPMVs are not usually tested before fever cases are treated as malaria or refer clients. The aim of this study was to explore the factors influencing caregivers’ acceptance of the test, treatment and referral practices for malaria management provided by CPs and PPMVs in Kaduna and Lagos states, Nigeria. Methods A cross-sectional quantitative telephone survey was conducted among 150 caregivers of children under five years old who received malaria services from trained CPs and PPMVs between May and July 2022. Descriptive and bivariate analyses were performed to identify factors significantly associated with the acceptability of malaria management services. All statistically significant factors from the bivariate analysis were explored using logistic regression models, and odds ratios (ORs) with confidence intervals (CIs) were calculated to predict acceptability. The 95% level was used to define statistically significant associations (p ≤ 0.05). Results All caregivers were asked questions that aided in obtaining a diagnosis of malaria. More than two-thirds of the caregivers (68%) reported that the child was tested by a CP/PPMV. Among those treated (148), 89% reported that the child was administered artemisinin combination therapy (ACT) irrespective of whether the child tested positive or negative for malaria. At the bivariate level, acceptability was greater among caregivers of children aged 13 months and older than among caregivers of children aged 0–12 months (93% vs. 76%, p = 0.004). Caregivers of children who prescribed ACT had greater acceptance than did those not prescribing ACT (92% vs. 69%, p = 0.010). Multivariate analysis revealed that these relationships held. Conclusions The adoption of the test, treat, and refer practice as a standard approach by CPs and PPMVs could replace the widespread practice of prescribing medications without conducting tests. This shift has the potential to improve the quality of malaria management services and enhance patient outcomes.
Læs mere Tjek på PubMedMalaria Journal, 11.10.2024
Tilføjet 11.10.2024
Abstract Background Malaria affects children under the age of five and pregnant women, leading to high morbidity and mortality rates. In sub-Saharan Africa, Patent and Proprietary Medicine Vendors (PPMVs) have been identified as key players in the provision of malaria treatment due to their accessibility and availability in communities, but PPMVs are not usually tested before fever cases are treated as malaria or refer clients. The aim of this study was to explore the factors influencing caregivers’ acceptance of the test, treatment and referral practices for malaria management provided by CPs and PPMVs in Kaduna and Lagos states, Nigeria. Methods A cross-sectional quantitative telephone survey was conducted among 150 caregivers of children under five years old who received malaria services from trained CPs and PPMVs between May and July 2022. Descriptive and bivariate analyses were performed to identify factors significantly associated with the acceptability of malaria management services. All statistically significant factors from the bivariate analysis were explored using logistic regression models, and odds ratios (ORs) with confidence intervals (CIs) were calculated to predict acceptability. The 95% level was used to define statistically significant associations (p ≤ 0.05). Results All caregivers were asked questions that aided in obtaining a diagnosis of malaria. More than two-thirds of the caregivers (68%) reported that the child was tested by a CP/PPMV. Among those treated (148), 89% reported that the child was administered artemisinin combination therapy (ACT) irrespective of whether the child tested positive or negative for malaria. At the bivariate level, acceptability was greater among caregivers of children aged 13 months and older than among caregivers of children aged 0–12 months (93% vs. 76%, p = 0.004). Caregivers of children who prescribed ACT had greater acceptance than did those not prescribing ACT (92% vs. 69%, p = 0.010). Multivariate analysis revealed that these relationships held. Conclusions The adoption of the test, treat, and refer practice as a standard approach by CPs and PPMVs could replace the widespread practice of prescribing medications without conducting tests. This shift has the potential to improve the quality of malaria management services and enhance patient outcomes.
Læs mere Tjek på PubMedYukiko Miyazaki, Shinya Miyazaki
Trends in Parasitology, 10.10.2024
Tilføjet 10.10.2024
The human malaria parasite Plasmodium falciparum causes the most severe form of malaria in endemic regions and is transmitted via mosquito bites. To better understand the biology of this deadly pathogen, a variety of P. falciparum reporter lines have been generated using transgenic approaches to express reporter proteins, such as fluorescent proteins and luciferases. This review discusses the advances in recently generated P. falciparum transgenic reporter lines, which will aid in the investigation of parasite physiology and the discovery of novel antimalarial drugs. Future prospects for the generation of new and superior human malaria parasite reporter lines are also discussed, and unresolved questions in malaria biology are highlighted to help boost support for the development and implementation of malaria treatments.
Læs mere Tjek på PubMedArega Tsegaye, Assalif Demissew, Ashenafi Abossie, Hallelujah Getachew, Kassahun Habtamu, Teshome Degefa, Xiaoming Wang, Ming-Chieh Lee, Daibin Zhong, James W. Kazura, Guiyun Yan, Delenasaw Yewhalaw
PLoS One Infectious Diseases, 10.10.2024
Tilføjet 10.10.2024
by Arega Tsegaye, Assalif Demissew, Ashenafi Abossie, Hallelujah Getachew, Kassahun Habtamu, Teshome Degefa, Xiaoming Wang, Ming-Chieh Lee, Daibin Zhong, James W. Kazura, Guiyun Yan, Delenasaw Yewhalaw Background Thioester-containing protein 1 (TEP1) is a crucial component of mosquitoes’ natural resistance to parasites. To effectively combat malaria, there is a need to better understand how TEP1 polymorphism affects phenotypic traits during infections. Therefore, the purpose of this study was to determine the Tep1 genotype frequency in malaria vector populations from south-western Ethiopia and investigate its effect on Plasmodium oocyst development in Anopheles arabiensis populations. Methods Using standard dippers, Anopheles mosquito larvae were collected from aquatic habitats in Asendabo, Arjo Dedessa, and Gambella in 2019 and 2020. Collected larvae were reared to adults and identified morphologically. Female An. gambiae s.l. were allowed to feed on infected blood containing the same number of gametocytes obtained from P. falciparum and P. vivax gametocyte-positive individuals using indirect membrane feeding methods. Polymerase Chain Reaction (PCR) was used to identify An. gambiae s.l. sibling species. Three hundred thirty An. gambiae s.l. were genotyped using Restricted Fragment Length Polymorphism (RFLP) PCR and sub samples were sequenced to validate the TEP1 genotyping. Results Among the 330 samples genotyped, two TEP1 alleles, TEP1*S1 (82% frequency) and TEP1*R1 (18% frequency), were identified. Three equivalent genotypes, TEP1*S1/S1, TEP1*R1/R1, and TEP1*S1/R1, had mean frequencies of 65.15%, 2.12%, and 32.73%, respectively. The nucleotide diversity was ranging from 0.36554 to 0. 46751 while haplotype diversity ranged from 0.48871 to 0.63161, across all loci. All sample sites had positive Tajima’s D and Fu’s Fs values. There was a significant difference in the TEP1 allele frequency and genotype frequency among mosquito populations (p < 0.05), except populations of Anopheles arabiensis from Asendabo and Gambella (p > 0.05). In addition, mosquitoes with the TEP1 *RR genotype were susceptible and produced fewer Plasmodium oocysts than mosquitoes with the TEP1 *SR and TEP1 *SS genotypes. Conclusion The alleles identified in populations of An. arabiensis were TEP1*R1 and TEP1*S1. There was no significant variation in TEP1*R1 allele frequency between the high and low transmission areas. Furthermore, An. arabiensis carrying the TEP1*R1 allele was susceptible to Plasmodium infection. Further studies on vector-parasite interactions, particularly on the TEP1 gene, are required for vector control techniques.
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