Malaria Journal最新文献

{"title":"Post-treatment transmissibility of Plasmodium falciparum infections: an observational cohort study.","authors":"Kassahun Habtamu, Hallelujah Getachew, Ashenafi Abossie, Assalif Demissew, Arega Tsegaye, Teshome Degefa, Daibin Zhong, Xiaoming Wang, Ming-Chieh Lee, Guofa Zhou, Solomon Kibret, Christopher L King, James W Kazura, Beyene Petros, Delenasaw Yewhalaw, Guiyun Yan","doi":"10.1186/s12936-025-05279-9","DOIUrl":"10.1186/s12936-025-05279-9","url":null,"abstract":"<p><strong>Background: </strong>Strengthening malaria control and expediting progress toward elimination requires targeting gametocytes to interrupt transmission. Artemisinin-based combination therapy (ACT) effectively clears Plasmodium falciparum asexual parasites and immature gametocytes but has a limited impact on mature gametocytes, which mosquitoes ingest during a blood meal. To address this gap, the World Health Organization recommends adding a single low dose of primaquine (PQ) to ACT regimens. This study assessed the efficacy of a single low-dose PQ for P. falciparum gametocyte clearance and evaluated mosquito infectiousness in Ethiopia.</p><p><strong>Methods: </strong>A prospective cohort study was conducted using passive case detection to enrol individuals with uncomplicated P. falciparum malaria at six health facilities. Participants were treated with either ACT alone or ACT plus 0.25 mg/kg single-dose PQ (ACT + PQ) and followed for 28 days with weekly visits. Blood smears for parasite counts, filter paper samples for DNA isolation, and whole blood for RNA preservation were collected on days 0, 7, 14, 21, and 28. On day 7, venous blood was obtained for membrane feeding assays using the Hemotek^® system to assess mosquito infection. Logistic regression analysed mosquito infection predictors, while gametocyte prevalence was compared between treatment arms using χ² or Fisher's exact tests.</p><p><strong>Results: </strong>Of 304 screened patients, 192 were enroled, with a median age of 23 (IQR 17-30) years; 65.7% were male. Post-treatment, 11 human-to-mosquito transmission cases were identified on day 7. Participants receiving ACT + SLD-PQ were significantly less likely to be infectious on day 7 (OR 0.12, 95% CI 0.02-0.57, p = 0.008) and had a significantly reduced prevalence of gametocytes (OR 0.22, 95% CI 0.06-0.83, p = 0.026) compared to those receiving ACT alone.</p><p><strong>Conclusion: </strong>A single course of low-dose primaquine (PQ) given with ACT significantly decreases the prevalence of gametocytaemia. Furthermore, membrane-feeding assays show that this combination also considerably lowers mosquito infection, confirming existing knowledge and emphasizing the promise of low-dose PQ as a successful transmission-blocking strategy in managing malaria.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"87"},"PeriodicalIF":2.4,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11917023/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143649786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial distribution of malaria among under-five children and associated factors in Tanzania: a spatial and multilevel analysis.","authors":"Yaregal Animut, Solomon Gedlu Nigatu, Rediet Eristu Teklu, Saron Abeje Abiy","doi":"10.1186/s12936-025-05313-w","DOIUrl":"10.1186/s12936-025-05313-w","url":null,"abstract":"<p><strong>Background: </strong>Malaria is a major public health problem in Tanzania, accounting for 3.1% of the global cases, with under-five children being particularly vulnerable. Over half of malaria deaths in Tanzania occurred among under-five children. Identifying the spatial determinants of malaria is crucial for optimizing targeted interventions to reduce morbidity and mortality in this vulnerable population. Therefore, this study aimed to assess the spatial determinants of malaria and factors associated with malaria infection among under-five children in Tanzania.</p><p><strong>Methods: </strong>A secondary data analysis was carried out using the Tanzanian Demographic and Health Survey and Malaria Indicator Survey (TDHS-MIS) 2022 data. A total weighted sample of 4971 under-five children was included in the analysis. Spatial determinants of malaria were identified by ordinary least square and geographically weighted regression analysis. A multilevel binary logistic regression model was fitted to identify factors associated with malaria infection among under-five children.</p><p><strong>Results: </strong>Malaria among under-five children was spatially clustered in Tanzania (Moran's Index = 0.14, p-value < 0.0001). Significant primary clusters of malaria were identified in the Northwestern part of the country (western and Lake zones) (log-likelihood ratio (LLR = 80.22, p < 0.0001) and secondary clusters in the Mtwara region (LLR = 16.04, p < 0.0001). Wealth index and access to health care were significant determinants of spatial clustering of malaria among under-five children. In the multilevel analysis, maternal education [primary level (AOR = 0.71, 95% CI 0.52-0.97)], child age of 48-59 months (AOR = 3.17, 95% CI: 1.80-5.62), family size of 5 to 10 (AOR = 1.69, 95%CI 1.12, 2.54), being in poor wealth index (AOR = 2.56, 95% CI 1.18-5.57), and unimproved roof (AOR = 1.49, 95% CI 1.04-2.16) were significantly associated with malaria infection among under-five children.</p><p><strong>Conclusion and recommendation: </strong>Malaria among under-five children in Tanzania shows significant spatial clustering, particularly in the Northwestern and Southern parts of the country. This spatial clustering of malaria was attributed to poor socioeconomic status and lack of access to health care. Improving access to health care and enhancing malaria prevention measures for the economically disadvantaged group could have a better impact on reducing the burden of malaria.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"86"},"PeriodicalIF":2.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11910873/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time to loss of physical integrity of attractive targeted sugar bait (ATSB) stations in Western Province, Zambia: a survival analysis.","authors":"Refilwe Y Karabo, Masuzyo H Mundia, Mwansa Mwenya, Kochelani Saili, John Miller, Kafula Silumbe, Irene Kyomuhangi, Joseph Wagman, Javan Chanda, Erica Orange, Busiku Hamainza, Angela F Harris, Julian Entwistle, Laurence Slutsker, Thomas R Burkot, Megan Littrell, Thomas P Eisele, Ruth A Ashton, Joshua Yukich","doi":"10.1186/s12936-025-05316-7","DOIUrl":"10.1186/s12936-025-05316-7","url":null,"abstract":"<p><strong>Background: </strong>Attractive targeted sugar baits (ATSBs) are a potential addition to an integrated vector management strategy against malaria. ATSB stations, which include a sugar bait and an ingestion toxicant, could potentially be deployed to attract-and-kill mosquitoes and thereby prevent malaria transmission. The physical durability of these stations is likely to be an important factor in decisions around future use strategies. This study measured the duration of physical integrity of the ATSB Sarabi v1.2 stations used in Western Zambia, as part of a Phase III cluster RCT.</p><p><strong>Methods: </strong>ATSB stations were installed and followed as a cohort on the external walls of selected sleeping structures in households in trial clusters (10-11 per cluster). Monthly visits were made to assess the presence and condition of the ATSBs from November 2022 to June 2023. A rolling cohort approach was used, whereby new ATSB stations were used to replace those which failed or were lost-to-follow-up, and these were subsequently enrolled in the cohort. Information on structure construction and ATSBs location on the walls was also collected. Median ATSB survival and associated factors were analysed with Kaplan-Meier curves and Cox-Proportional hazard models.</p><p><strong>Results: </strong>Including replacements, a total of 1107 ATSBs were installed across 304 sleeping structures in 206 households, and 5696 ATSB-visits were made. Common types of damage observed were holes/tears, mold, and leakage of bait. While the median survival time for the devices was 5 months (149 days) for all stations in the study, the median survival time was longer than the transmission season for stations installed in locations well protected by the roof (> 218 days). ATSB station survival was longer when installed on structures with thatched roofs compared to iron-sheet roofs (HR 0.37, 95% CI 0.26-0.47, p < 0.001), and where there was \"excellent protection\" (HR = 0.36, 95% CI 0.25-0.49, p < 0.001), compared to \"no protection\".</p><p><strong>Conclusions: </strong>Study results suggest that the majority of ATSB stations deployed in this setting will remain intact for a 7-month seasonal deployment period if stations are installed in locations protected from weather elements, such as underneath the overhang of thatched roof. Further research is needed to understand factors that influence the physical integrity and efficacy of ATSB stations in addition to those observed in this study.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"84"},"PeriodicalIF":2.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11909832/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission.","authors":"Maxwell G Machani, Shirley A Onyango, Irene Nzioki, Sylvia Milanoi, Godfrey Nattoh, John Githure, Harrysone Atieli, Chloe Wang, Ming-Chieh Lee, Goufa Zhou, Andrew K Githeko, Yaw A Afrane, Eric Ochomo, Guiyun Yan","doi":"10.1186/s12936-025-05332-7","DOIUrl":"10.1186/s12936-025-05332-7","url":null,"abstract":"<p><strong>Background: </strong>Increasing unplanned urbanization in tropical Africa may create new niches for malaria vectors, raising transmission risk, yet control efforts focus on rural ecosystems. Understanding mosquito diversity, ecology and biting behaviour in urban areas is crucial for effective control. This study assessed Anopheles diversity, abundance, behaviour, and Plasmodium infection rates in Kisumu city, Kenya.</p><p><strong>Methods: </strong>Indoor and outdoor host-seeking and resting adult mosquitoes were collected using CDC miniature light traps (CDC-LT) and Prokopack aspirators along an urban-rural transect. Anophelines were identified morphologically, with Anopheles gambiae sensu lato (s.l.) and Anopheles funestus group further distinguished to siblings using polymerase chain reaction (PCR). Sporozoite infection rates were determined using a multiplexed real-time quantitative PCR (qPCR) assay.</p><p><strong>Results: </strong>A total of 3,394 female Anopheles mosquitoes were collected: An. gambiae s.l. (68%), An. funestus s.l. (19.8%), Anopheles coustani (7.8%), Anopheles pharoensis (2.6%), Anopheles maculipalipis (1.6%), and Anopheles leesoni (0.2%). All six species were found in urban zone, but only three were in peri-urban and rural sites. Overall, urban collection accounted for 55.5% of mosquitoes, followed by peri-urban (30%) and rural sites (14.5%). Anopheles arabiensis dominated urban (84.3%) and peri-urban (89%) sites, while An. gambiae sensu stricto (s.s.) was predominant in rural zone (60.2%) alongside An. arabiensis (39.7%). Anopheles funestus was predominant in peri-urban (98.4%) and rural (85.7%) areas, while An. leesoni accounted for 1.6% and 14.3%, respectively. In urban areas, all An. funestus s.l. samples were An. funestus s.s.. Most (55.5%) of Anopheles mosquitoes were collected indoors, while secondary vectors were mainly outdoors. Overall, sporozoite rates were higher outdoors (3.5%) than indoors (1.45%) in rural areas. Indoor rates were 2.5% (An. funestus), 1.4% (An. gambiae s.s.), and 1% (An. arabiensis). Outdoors, An. gambiae had 5.3%, and An. arabiensis 2.1%. In peri-urban areas, An. gambiae had 2.3%. No sporozoites were found in urban samples.</p><p><strong>Conclusion: </strong>The study highlights a shift in Anopheles diversity towards urban areas with increased outdoor activity and outdoor malaria transmission in rural and peri-urban areas, underscoring the need for tools targeting outdoor-biting mosquitoes. The presence of An. funestus in urban settings emphasizes the need for sustained entomological surveillance to inform integrated vector control.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"85"},"PeriodicalIF":2.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11909859/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple insecticide resistance in Anopheles funestus from Mopeia, Central Mozambique.","authors":"Caroline Kiuru, Luis Constantino, Gildo Cole, Jonathan Karisa, Caroline Wanjiku, Miguel Okoko, Baltazar Candrinho, Francisco Saute, N Regina Rabinovich, Carlos Chaccour, Marta Ferreira Maia","doi":"10.1186/s12936-025-05321-w","DOIUrl":"10.1186/s12936-025-05321-w","url":null,"abstract":"<p><strong>Background: </strong>The main malaria vector control methods implemented in Mozambique are insecticide-treated nets (ITN's) and indoor residual spraying (IRS). These insecticide-based interventions are currently threatened by the rapidly spreading insecticide resistance in several major malaria vectors. Monitoring of insecticide resistance is necessary to inform the selection of insecticides by control programmes. This study describes the insecticide resistance profiles of the main malaria vector, Anopheles funestus sensu lato. in Mopeia district, a malaria holoendemic area of the Zambezia province of Mozambique.</p><p><strong>Methods: </strong>Anopheles adults and larvae were collected from 15 sentinel sites across the district between October 2021 and September 2022. Wild-caught, unfed female adults were collected using CDC-light traps and pooled over three days before exposure to the test insecticide. For mosquitoes collected as larvae, F0 adults aged 3-5 days post-emergence were used for insecticide susceptibility testing. Resistance to bendiocarb, DDT, deltamethrin and pirimiphos-methyl was evaluated using the standard WHO tube bioassay. The mechanism of resistance was probed using the PBO (piperonyl butoxide) synergistic bioassay. The presence and frequency of different genetic mutations associated with insecticide resistance was assessed using polymerase chain reaction, including A296S-Rdl, L119F-GSTe2 and 6.5 kb SV (structural variation) insertion.</p><p><strong>Results: </strong>A total of 1349 female Anopheles mosquitoes (controls included) were used for susceptibility tests with discriminating insecticide concentrations. Phenotypic resistance to bendiocarb, DDT, deltamethrin and pirimiphos-methyl was observed, with 37%, 79%, 14% and 67% mortality rate respectively. Pre-exposure to PBO partially restored susceptibility to deltamethrin to a mortality rate of 80%. The frequency of the insecticide resistance mutations was 0.49, 0.05 and 0.92, for A296S-Rdl, L119F-GSTe2 and 6.5 kb SV insertion, respectively.</p><p><strong>Conclusion: </strong>Malaria vectors in Mopeia exhibit resistance to all four major public health insecticide classes: pyrethroids, organophosphates, organochlorides and carbamates. This highlights the urgent need to adopt new insecticide classes for vector control interventions. The partial restoration of susceptibility by PBO suggests resistance is being driven by various mechanisms including the involvement of metabolic resistance through cytochrome P450 monooxygenase enzymes and glutathione S-transferases.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"81"},"PeriodicalIF":2.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11907927/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of malaria treatment interventions: a critical analysis of government initiatives and causes of treatment failure at Port Loko Government Hospital, Sierra Leone.","authors":"Lawrence Sao Babawo, Rashid Bundu Kpaka, Daniel Karim Dauda Sesay","doi":"10.1186/s12936-025-05330-9","DOIUrl":"10.1186/s12936-025-05330-9","url":null,"abstract":"<p><strong>Background: </strong>Malaria remains a significant public health challenge, particularly in sub-Saharan Africa, where it accounts for high morbidity and mortality rates. Sierra Leone, including Port Loko District, continues to experience a high burden of malaria despite government interventions. This study evaluates the existing government interventions for malaria treatment at Port Loko Government Hospital, examining the socio-economic determinants contributing to malaria treatment failure.</p><p><strong>Methods: </strong>The study employed a cross-sectional study design with a quantitative approach, involving 150 health workers and 150 women of childbearing age. A purposive stratified random sampling technique was used to ensure diverse representation. Primary data were collected using structured questionnaires, while secondary data were extracted from the District Health Information System (DHIS) and hospital records. Data were analysed using SPSS version 28.0, applying descriptive statistics (frequencies, percentages, means and SD) and inferential analyses (Chi-square tests and binary logistic regression) to assess associations between socio-economic factors and treatment-seeking behaviours.</p><p><strong>Results: </strong>Findings revealed that 90% of health workers were aware of malaria interventions, but only 68% reported high adherence to treatment guidelines. Among women of childbearing age, 40% sought malaria treatment at drug stores or pharmacies due to financial constraints, and a significant association was observed between socio-economic status and healthcare-seeking behaviour (² = 9.32, df = 4, p = 0.05). Despite the fact that 73.3% reported the use of long-lasting insecticidal nets (LLINs), malaria prevalence remained high, suggesting additional risk factors beyond bed net usage.</p><p><strong>Conclusion: </strong>This study highlighted persistent challenges in malaria control, including inadequate healthcare access, non-adherence to treatment regimens, and socio-economic constraints. Policy recommendations include strengthening malaria treatment adherence programmes, improving healthcare accessibility, and enhancing community-based malaria prevention strategies.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"83"},"PeriodicalIF":2.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11909949/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating the hole surface area of insecticide-treated nets using image analysis, manual hole counting and exact hole measurements.","authors":"Emmanuel Mbuba, Natalia Mañas-Chavernas, Sarah J Moore, Philipo David Ruzige, Dickson Kobe, Jason Moore, Rose Philipo, Noela Kisoka, Gianpaolo Pontiggia, Frank Chacky, Charles Dismasi Mwalimu, Philippe Claude Cattin, Julia Wolleb, Robin Sandkuehler, Amanda Ross","doi":"10.1186/s12936-025-05324-7","DOIUrl":"10.1186/s12936-025-05324-7","url":null,"abstract":"<p><strong>Background: </strong>The physical integrity of insecticidal-treated nets (ITNs) is important for creating a barrier against host-seeking mosquitoes and, therefore, influences people's perception of the net's effectiveness and their willingness to use it. Monitoring the physical integrity of ITNs over time provides information for replenishment schedules and purchasing decisions. Currently, the assessment of physical integrity of ITNs is conducted by manually counting holes and estimating their size to class the net as functional or not. This approach is laborious to routinely conduct during field surveys of ITNs. Automated image analysis may provide a rapid assessment of the physical integrity of ITNs but it is not known if the images can capture sufficient information. As a first step, this study aimed to assess the agreement between estimated hole surface areas derived from (1) manually segmented images, (2) manual hole counting compared to (3) ground truth obtained by calibrated close-up shots of individual holes.</p><p><strong>Methods: </strong>The physical integrity of 75 ITNs purposely selected from an ongoing study was assessed by manual hole counting, image analysis and ground truth. For the image analysis, a graphical user interface was developed and used for the segmentation of holes visible in photographs taken from each side of the net. The hole surface area was then computed from this data. The agreement between the estimates from image analysis and manual hole counting was compared to the ground truth using the Bland-Altman method.</p><p><strong>Results: </strong>There was substantial agreement between the manually segmented image analysis estimates and the ground truth hole surface areas. The overall bias was small, with a mean ratio of the hole surface area from image analysis to the ground truth of 0.70, and the 95% limits of agreement ranging from 0.35 to 1.38. Manual hole counting underestimated the hole surface area compared to the ground truth, particularly among nets with holes above 10 cm in diameter.</p><p><strong>Conclusion: </strong>Images coupled with manual segmentation contain sufficient information to calculate hole surface area. This lays the groundwork for incorporating automatic hole detection, and then assessing whether this method will offer a fast and objective method for routine assessment of physical integrity of ITNs. While the WHO method underestimated the hole surface area, it remains useful in classifying nets as either serviceable or too torn because the cut-off is specific to this method.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"82"},"PeriodicalIF":2.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11909875/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of insecticide resistance mechanisms in the Anopheles gambiae population of Sierra Leone.","authors":"Kevin Ochieng' Opondo, Evelyne Alyko, Samuel Smith, Rebecca Levine, Jenny Donnelly, Tony Hughes, David Schnabel, Ramlat Jose, Alpha Jalloh, Umaru Lolleh, Samuel Conteh, Laurent Iyikirenga, Djenam Jacob, Miriam Mokuena, Frederick Yamba, Yemane Yihdego","doi":"10.1186/s12936-025-05267-z","DOIUrl":"10.1186/s12936-025-05267-z","url":null,"abstract":"<p><strong>Background: </strong>Information on the status of insecticide resistance in malaria vectors is critical for implementing effective malaria vector control. The Sierra Leone National Malaria Control Programme, in collaboration with the PMI VectorLink project, assessed the resistance status to insecticides commonly used in public health, and associated resistance mechanisms in Anopheles gambiae, the main vector of malaria in Sierra Leone.</p><p><strong>Methods: </strong>The susceptibility of An. gambiae against pyrethroids with and without piperonyl butoxide (PBO), chlorfenapyr, clothianidin, bendiocarb and pirimiphos-methyl was evaluated in four districts of Sierra Leone in 2018 and 2019 using WHO and CDC bottle bioassay protocols. A subset of samples that were exposed to the insecticides were screened for molecular markers of insecticide resistance, knock-down resistance (kdr) L1014F, 1014S and N1575Y, and (ace-1-G119S).</p><p><strong>Results: </strong>Anopheles gambiae from all sites were resistant to the diagnostic doses of three pyrethroids: deltamethrin, permethrin and alpha-cypermethrin. Intensity of resistance to all three pyrethroids was high, with less than 95% mortality at 10X concentration. However, pre-exposure of An. gambiae to PBO increased overall mortality by 41.6%, 50.0% and 44.0% for deltamethrin, permethrin and alpha-cypermethrin, respectively. The vector was susceptible to chlorfenapyr, clothianidin and pirimiphos-methyl, while bendiocarb showed possible resistance. The frequency of kdr alleles was 98.2% for L1014F, 2.1% for 1014S and 8.9% for N1575Y, while the frequency of the Ace-1 G119S allele was 13.6%. Significant deviation from the Hardy-Weinberg equilibrium and deficiency of heterozygotes was detected only at the G119S locus of An. gambiae (p < 0.0001). Of the 191 An. gambiae sensu lato that were molecularly identified to the species level, 81.7% were An. gambiae sensu stricto (95% CI 75.3-86.7), followed by Anopheles coluzzii (17.8%, 95% CI (12.8-24.1) with one hybrid of An. gambiae/An. coluzzii 0.5%, 95% CI (0.03-3.3).</p><p><strong>Conclusion: </strong>Malaria vectors were highly resistant to pyrethroids but exposure to PBO partially restored susceptibility in An. gambiae s.l. in Sierra Leone. Malaria vectors were susceptible to chlorfenapyr, clothianidin and pirimiphos-methyl with possible resistance to bendiocarb. These data informed the selection and distribution of ITN PBO in Sierra Leone's mass campaigns in 2020 and selection of clothianidin for indoor residual spraying in 2021.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"80"},"PeriodicalIF":2.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11907884/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143625304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Through the eyes of the participant: using photovoice to understand the experiences and effects of ivermectin MDA in the context of the BOHEMIA clinical trial in Kwale, Kenya.","authors":"Truphena Onyango, Khadija Nuru, Karisa Kazungu, Winnie Wangari, Carlos Chaccour, N Regina Rabinovich, Joseph Mwangangi, Marta Maia, Caroline Jones","doi":"10.1186/s12936-025-05320-x","DOIUrl":"10.1186/s12936-025-05320-x","url":null,"abstract":"<p><strong>Background: </strong>Assessing the acceptability of new malaria control interventions in clinical trials can be complex due to the need for strict ethical standards and specific trial procedures. While in-depth interviews and focus group discussions can provide useful insights, a more participatory method of data collection which complements these methods is photovoice. Photovoice offers a unique approach, empowering participants to share their experiences and perceptions on their own terms. Photovoice was employed alongside the BOHEMIA clinical trial (a trial investigating the safety and efficacy of ivermectin mass-drug administration (MDA) for malaria control) to explore participants' views on the trial and the effects of the intervention on individuals and communities.</p><p><strong>Methods: </strong>Two participants from each of five villages involved in the trial (two intervention, three control) were purposively selected and trained on the ethical and technical use of cameras. During the final round of the intervention, participants photographed their trial experiences and the MDA effects. Two picture-sharing discussions were conducted to explore the picture content and reasons for their inclusion.</p><p><strong>Results: </strong>Both intervention and control groups expressed confidence in the trial procedures, with pictures capturing barcode scanning and health assessments, activities reported to provide reassurance and enhance trust. Photos from both groups showed positive outcomes such as improved appetite and fewer mosquitoes. However, photos from the ivermectin group also showed clearing of jiggers and killing of bed bugs. Images of rashes, described as a negative effect of the MDA, were taken by both groups. Pictures of mosquito breeding sites and sources of intestinal worms were also shared by both groups.</p><p><strong>Conclusion: </strong>Photovoice provided valuable insights into trial experiences, intervention effects, and revealed unexpected outcomes, such as killing of bedbugs, that warrant deeper exploration. It exposed broader community concerns of the source of malaria and intestinal worms not addressed by either the intervention or local health authorities.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"79"},"PeriodicalIF":2.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11905568/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143616220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genome-wide scanning for genetic markers associated with anti-malarial drugs sensitivity of Plasmodium falciparum isolates from the China-Myanmar border region.","authors":"Yini Tian, Run Ye, Yufu Huang, Dongmei Zhang","doi":"10.1186/s12936-025-05319-4","DOIUrl":"10.1186/s12936-025-05319-4","url":null,"abstract":"<p><strong>Background: </strong>Understanding the emergence and spread of anti-malarial resistance, particularly to artemisinin and its partner drugs, is essential for eradicating malaria in worldwide. To identify genetic markers associated with susceptibility to common anti-malarial drugs, the in vitro sensitivities of anti-malarial drugs were evaluated, and a genome-wide association study of Plasmodium falciparum susceptibility in vitro to multiple anti-malarial drugs was conducted.</p><p><strong>Methods: </strong>Genomic DNA from 34 samples of P. falciparum collected between 2007 and 2010 in the Nabang-Lazan Valley along the China-Myanmar border was extracted and subjected to whole-genome sequencing. The standard SYBR Green I-based fluorescence assay and RSA assay were used to evaluated the in vitro sensitivities of anti-malarial drugs. Plink v1.90 was used to investigate the associations of genome-wide SNP with in vitro sensitivities to anti-malarial drugs.</p><p><strong>Results: </strong>The proportion of isolates showed reduced-susceptible to CQ,SP,QN,PPQ and PND were 88.24%,92.59%,8.82%,8.82%,5.88%, respectively. 93.54% of isolates showed high level of the IC₅₀ values of CQ have a pfcrt CIETS mutations. The isolates with pfdhfr IRNI, NRNL and IRNL mutations showed high SP IC₅₀ values. SNPs on pfhsp90 and pfevp1 showed significant association with IC₅₀ values of CQ. Of particular interest is the significant association found between a locus on chromosome 13 and the sensitivity to dihydroartemisinin. This locus is situated within the gene encoding the inner membrane complex protein 1F (IMC1F),which has been found to be associated with the kelch13 compartment in schizont stages of P. falciparum.</p><p><strong>Conclusions: </strong>Multiple genetic markers correlating with anti-malarial drug susceptibility were identified in the study, which provide a reference for further investigations into the association between oxidative stress-mediated activity and anti-malarial drugs susceptibility.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"78"},"PeriodicalIF":2.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11899373/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143616193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}