Malaria Journal最新文献

{"title":"Does mass chloroquine treatment have any role in the elimination of Plasmodium vivax ?","authors":"Nicholas J White, Somya Mehra, James A Watson","doi":"10.1186/s12936-025-05399-2","DOIUrl":"10.1186/s12936-025-05399-2","url":null,"abstract":"<p><p>Countries in the Greater Mekong sub-region (GMS) have been encouraged to deploy mass chloroquine treatments given monthly for four months to reduce the burden of vivax malaria. This paper summarizes briefly current knowledge on Plasmodium vivax epidemiology, the biology of vivax relapse and previous experience using dihydroartemisinin-piperaquine mass treatments in the GMS to show why this approach would be extremely cost-ineffective. Around 800 full treatment courses in 200 people would be needed to prevent one symptomatic case. Mass chloroquine treatment will contribute little or nothing to the elimination of vivax malaria in this area.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"166"},"PeriodicalIF":2.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12105338/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144151005","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":"Prevalence of malaria and associated risk factors among febrile under-five refugee children attending Panyadoli Health Centre III, Kiryandongo District, Mid-western Uganda.","authors":"Dorcus Acan, Robert Opiro, Benson Musinguzi, Bosco B Agaba, Simon Peter Alarakol","doi":"10.1186/s12936-025-05404-8","DOIUrl":"10.1186/s12936-025-05404-8","url":null,"abstract":"<p><strong>Background: </strong>Malaria presents a big threat to the health of refugees, internally displaced persons, returnees and other such persons affected by humanitarian emergencies, with almost two thirds of these groups of persons living in malaria endemic regions. The aim of this study was to determine the prevalence of malaria and associated risk factors among refugee children < 5 years attending a Health Centre in Panyadoli Refugee Settlement Camp, Kiryandongo District, Uganda.</p><p><strong>Methods: </strong>A cross-sectional survey was done between February to April 2022, targeting refugee children < 5 years old seeking healthcare at Panyadoli Health Centre III in Kiryandongo District. Simple random sampling was employed to select 380 participants, who were then tested for the presence of malaria parasites using malaria rapid diagnostic tests and microscopy techniques. Data on risk factors of malaria was collected using a pre-tested and standardized semi-structured questionnaire. Bivariate and multivariate logistic regression analyses was used to identify the risk factors for malaria infections, at 95% confidence interval and p < 0.05.</p><p><strong>Results: </strong>Malaria prevalence among the refugee children < 5 years attending Panyadoli HCIII was 12.6% [95% CI: 8.7-18.0]. The associated risk factors for malaria infection included: non-application of indoor residual spraying over the last 12 months [AOR = 4.323; 95% CI 1.231-7.212], history of malaria in children (AOR = 5.861; 95% CI 1.562-8.433], and not sleeping under insecticide-treated nets (AOR = 3.141; 95% CI 0.865-5.221).</p><p><strong>Conclusion: </strong>Malaria remains a threat to refugee children < 5 years old at Panyadoli Refugee Settlement Camp. Sustained implementation of IRS should be pursued through expanded geographic coverage and increased application frequency, in conjunction with complementary malaria control measures such as enhanced ITN distribution and IPT for pregnant women, to support long-term malaria reduction.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"162"},"PeriodicalIF":2.4,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12103808/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144142849","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":"Impact of indoor residual spraying on malaria incidence in Ugandan prisons: an interrupted time series analysis.","authors":"Joseph Byaruhanga, James Kisambu, Adoke Yeka, Arthur Bagonza","doi":"10.1186/s12936-025-05422-6","DOIUrl":"10.1186/s12936-025-05422-6","url":null,"abstract":"<p><strong>Background: </strong>Indoor residual spraying (IRS) is an effective intervention for reducing mosquito vector density and malaria transmission. Uganda Prison Services (UPS) routinely implements IRS for malaria control in main prison facilities; however, no assessment of its impact had been performed. The study assessed the general malaria incidence trends for 5 years and determined the impact of IRS on malaria incidence in the main prison facilities in Uganda.</p><p><strong>Methods: </strong>This was a cross-sectional study which employed interrupted time series analysis to determine the effect of IRS programme on malaria incidence in prisons located in two different regions of Uganda. The malaria incidence trends of two prison facilities per region (in similar settings) were compared, one being an IRS intervention facility and the other being a comparison facility (did not receive an IRS) over 5 years (2018-2022) in the central and northern regions of Uganda.</p><p><strong>Results: </strong>A total of 208 monthly malaria reports from all selected facilities (4) were reviewed. The peak malaria incidence rate was recorded from September to December across the years in both regions. The lowest incidence rate was recorded from January to March. The average monthly malaria incidence rate for the study period was much lower among the intervention facilities (7.1 and 13.3 cases per 1000 population per month for the central and northern regions, respectively) than among the comparison facilities (177.0 and 170.6 cases per 1000 population per month for the central and northern regions, respectively). The post-IRS intervention periods had lower malaria incidence rates than the pre-IRS periods across the intervention facilities in both regions. The IRS intervention had a statistically significant effect on reducing the malaria incidence rate in the intervention facility located in the northern region (slope: P = 0.001, CI [21.9, 67.7]).</p><p><strong>Conclusion: </strong>Indoor residual spraying reduced the malaria incidence rate among the intervention facilities in both regions, but a significant impact was recorded in the northern region, which is a region with higher malaria transmission rates than the central region. In situations of limited resources, IRS implementation should prioritize prisons located in high malaria transmission areas to achieve significant impacts.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"163"},"PeriodicalIF":2.4,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12105299/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144142848","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":"Prevalence, awareness, treatment-seeking behaviours and its implications in the control of malaria in Dumbu community, Donga-Mantung Division, North West Region, Cameroon.","authors":"Joan E E Eyong, Calvin B Ebai, Purity Awah, Antoine S Kada","doi":"10.1186/s12936-025-05249-1","DOIUrl":"10.1186/s12936-025-05249-1","url":null,"abstract":"<p><strong>Background: </strong>Malaria remains a major public health problem in Cameroon where it accounts for high rates of morbidity and mortality. The management of the disease has been made worst in the North West region of Cameroon and in Dumbu in particular by the on-going socio-political crisis since 2016, which has limited the transport of drugs to this community and has also forced the inhabitants of this community to rely on traditional concoctions for treatment with the notion that it is cheap. The aim of this study was to determine the prevalence of malaria, assess the malaria awareness level, the treatment-seeking behaviours, and its implications on the prevalence of malaria in the Dumbu community.</p><p><strong>Methods: </strong>Questionnaires were administered to consented individuals. Blood samples were collected by finger prick using sterile lancets and blood films prepared on well labelled glass slides. The dry blood films were stained using a 3% Giemsa staining solution for 30 min. Data was collected were later analysed using SPSS.</p><p><strong>Results: </strong>Out of the 385 persons screened, malaria was recorded in 107 persons (27.8%). Those in the age group 11-25 years old were the most infected with malaria prevalence of 32.3% (41/127) while those in the age group ≥ 50 years recorded the least prevalence [19.3% (11/57)] and the difference was not significant (χ² = 3.716, p = 0.294). Yaoundé quarter recorded the highest prevalence 32.7% (35/107) and males were more infected than females. On awareness level, they have heard of malaria and knew its causal agent to be an infected mosquito, 48.3% considered fever as the sign of the infection. Sixty-nine-point 8 percent (69.8%) of the population rushes to the health centre for treatment while 5.6% prefers herbal treatment.</p><p><strong>Conclusion: </strong>Malaria is still a health challenge in this area and people infected should be advised to seek treatment, whenever they have malaria from a health facility to ensure that the treatment given is appropriate.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"161"},"PeriodicalIF":2.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12100826/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128049","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":"Malaria control among Myanmar migrants in Thailand: a qualitative study of healthcare providers.","authors":"Nichakan Inthitanon, Piyarat Sripoorote, Yupaporn Wattanagoon, Pattamaporn Petchvijit, Ammarind Anantjitsupha, Kyawt Mon Win, Nattawan Rachaphaew, Khaing Zin Zin Htwe, Kritsana Suk-Aum, Peeriya Watakulsin, Liwang Cui, Jetsumon Sattabongkot, Daniel M Parker, Wang Nguitragool, Pyae Linn Aung","doi":"10.1186/s12936-025-05397-4","DOIUrl":"10.1186/s12936-025-05397-4","url":null,"abstract":"<p><strong>Background: </strong>Thailand has experienced a recent surge in malaria cases, particularly along the Thailand-Myanmar border, likely driven by the importation of infections by Myanmar migrants. Implementing malaria control measures, especially surveillance among these high-risk populations, presents significant challenges. This study aimed to identify key obstacles and propose targeted solutions for enhancing malaria control among Myanmar migrants in border areas of Thailand.</p><p><strong>Methods: </strong>A cross-sectional qualitative study was conducted in early 2024. Semi-structured interviews were held with 20 government healthcare providers and village health volunteers involved in malaria control across three districts in western Thailand with the highest malaria caseloads. Data were analysed using thematic analysis.</p><p><strong>Results: </strong>Respondents consistently linked the rise in malaria cases to increased cross-border migration from Myanmar following recent political unrest. Key challenges included difficulty locating and following up with short-term or undocumented migrants, language barriers that hinder health education, and delays in diagnosis because of limited infrastructure and reliance on rapid diagnostic tests in areas without electricity. Suggested solutions included deploying mobile malaria posts near informal border crossings, mandating malaria testing before worksite entry, and engaging local employers and community leaders to register new arrivals and support treatment adherence among migrants.</p><p><strong>Conclusions: </strong>Ongoing political instability in Myanmar continues to drive a large and dynamic population of migrants into Thailand's border regions, sustaining malaria importation and complicating elimination efforts. Tailored, migrant-responsive strategies, such as mobile surveillance near border crossings, community-based follow-up mechanisms, and infrastructure improvements, are urgently needed to close coverage gaps and achieve malaria elimination by 2030.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"160"},"PeriodicalIF":2.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096533/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128036","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":"Seasonal malaria chemoprevention in northern Mozambique: a cost-effectiveness analysis.","authors":"Neide Canana, Ivan Alejandro Pulido Tarquino, Sónia Enosse, Kevin Baker, Maria Rodrigues, Christian Rassi, Akashdeep Singh Chauhan, Chuks Nnaji, Baltazar Candrinho, Elisa M Maffioli","doi":"10.1186/s12936-025-05401-x","DOIUrl":"10.1186/s12936-025-05401-x","url":null,"abstract":"<p><strong>Background: </strong>Malaria is endemic in Mozambique and one of the leading causes of death in children under 5 years old. In 2020 the country adopted the WHO-recommended seasonal malaria chemoprevention (SMC) strategy and delivered the intervention in all 23 districts of Nampula province between January and April 2023. The aim of this study is to estimate the cost-effectiveness of SMC in Nampula, Mozambique.</p><p><strong>Methods: </strong>Financial cost of implementing SMC were estimated from a limited health care provider perspective for the year 2023 in US$. Data on resource use of the SMC implementation was assessed from Malaria Consortium records. The number of eligible and treated children was collected from surveys after cycle 4. The number of malaria cases, deaths and Disability Adjusted Life-Years (DALYs) averted were estimated based on data from Global Burden of Disease 2019, Malaria Indicator Survey 2018, and National Malaria Control Programme. Incremental cost-effectiveness ratios (ICERs) were estimated, and sensitivity analyses were used to test the robustness of the ICERs.</p><p><strong>Results: </strong>The total financial cost of SMC implementation in Nampula province in 2023 was estimated to be $7,871,361.72. The study estimated a cost per targeted child of $6.05 and a cost per child who received full 3-day course of sulfadoxine-pyrimethamine in combination with amodiaquine (SPAQ) of $7.92. Furthermore, the cost per household with eligible children visited by a community distributor was $7.65; the cost per child who received day 1 SPAQ was $7.85 and the cost per child who received day 1 SPAQ by community distributor adhering to directly observed treatment was $8.50. In addition, the estimated cost was $93.50 per malaria case averted, $3286.59 per malaria death averted, and $130.16 per DALY averted. The ICERs were robust to a variety of alternative assumptions on costs and benefit estimates. Finally, $1,726,189.63 could have been saved if no ineligible children (60-119 months old) were treated through the programme.</p><p><strong>Conclusions: </strong>In line with existing evidence from other African countries, SMC is found to be cost-effective in Mozambique. SMC is a beneficial prevention strategy to improve under-five health in the country, at a relatively low-cost.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"159"},"PeriodicalIF":2.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096524/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120107","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":"Forecasting malaria cases using climate variability in Sierra Leone.","authors":"Saidu Wurie Jalloh, Boniface Malenje, Herbert Imboga, Mary H Hodges","doi":"10.1186/s12936-025-05389-4","DOIUrl":"10.1186/s12936-025-05389-4","url":null,"abstract":"<p><strong>Background: </strong>Malaria continues to pose a public health challenge in Sierra Leone, where timely and accurate forecasting can guide more effective interventions. Although seasonal models such as Seasonal Autoregressive Integrated Moving Average (SARIMA) have traditionally been employed for disease forecasting, Artificial Neural Networks (ANNs) have gained attention for capturing complex temporal patterns that linear models may not fully capture.</p><p><strong>Methods: </strong>This study compares the forecasting performance of SARIMA and ANN models in forecasting malaria cases using malaria case data from 2018 to 2023. A baseline SARIMA model was developed and improved with exogenous climatic variables (precipitation, maximum temperature, and mean relative humidity) to form a SARIMAX approach. In parallel, an ANN was trained solely on historical malaria cases, without adding climatic variables.</p><p><strong>Results: </strong>SARIMA offered reasonable predictive capabilities but was outperformed by the ANN, which captured complex temporal patterns more effectively, decreasing forecast errors and improving its coefficient of determination <math><mrow><mo>(</mo> <msup><mi>R</mi> <mn>2</mn></msup> <mo>)</mo></mrow> </math> . The SARIMA model achieved an MAPE of 12.01%, which improved further to an MAPE of 11.45% with the inclusion of climatic variables. A strong positive correlation between precipitation (r = 0.68) and malaria cases was observed, while maximum temperature showed a moderate negative correlation (r = <math><mrow><mo>-</mo> <mn>0.45</mn></mrow> </math> ), and mean relative humidity demonstrated a moderate positive correlation (r = 0.55). The ANN model outperformed both the baseline SARIMA and SARIMAX models with the lowest MAPE of 6.68%.</p><p><strong>Conclusions: </strong>These findings underscore the ANN's ability to capture non-linear dynamics, even without explicit climate inputs. These results reinforce the value of machine learning modelling approaches in guiding malaria control strategies, particularly in high-burden settings like Sierra Leone.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"158"},"PeriodicalIF":2.4,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12093741/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111345","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 and temporal variation of malaria incidence in children under 10 years in a pyrethroid-resistant vector area in southern Benin.","authors":"Edouard Dangbenon, Mintodê Nicodème Atchadé, Martin C Akogbéto, Mahouton N Hounkonnou, Landry Assongba, Hilaire Akpovi, Manisha A Kulkarni, Natacha Protopopoff, Jackie Cook, Manfred Accrombessi","doi":"10.1186/s12936-025-05353-2","DOIUrl":"10.1186/s12936-025-05353-2","url":null,"abstract":"<p><strong>Background: </strong>Spatial and temporal identification of malaria-endemic areas is a key component of vector-borne disease control. Strategies to target the most vulnerable populations, the periods of high transmission and the most affected geographical areas, should make vector-borne disease control and prevention programmes more cost-effective. The present study focuses on the spatial and temporal dynamics of malaria cases and the exogenous factors influencing the transmission in an area with pyrethroid-resistant mosquito vector populations.</p><p><strong>Methods: </strong>A prospective cohort study of 1806 children under 10 years of age was conducted over 20 months to assess the risk of malaria incidence in the Cove-Zagnanado-Ouinhi (CoZO) health zone located in southern Benin. Childhood malaria data were used to identify malaria hotspots according to months of follow-up using spatial scanning methods based on the Kulldoff algorithm. Stability scores were calculated by season to assess incidence heterogeneity. Incidence values by month were aggregated with meteorological data; and demographic data were merged to detect cross-correlation between incidence and meteorological variables. Generalized equation estimators were chosen for their ability to handle intra-group correlation, ensuring robust and interpretable results despite the complexity of the data to identify factors explaining the spatio-temporal heterogeneity of malaria incidence in the CoZO health zone.</p><p><strong>Results: </strong>Malaria incidence ranged from 1.41 (95% IC 0.96-2.08) to 13.91 (95% IC 12.22-15.84) cases per 100 child-months. Spatial heterogeneity in malaria transmission hotspots was observed over the study period, with relative risks ranging from 1.59 (p-value = 0.032) to 16.24 (p-value = 0.002). There was a significant negative association (correlation coefficient = - 0.56) between malaria incidence and temperature; and a slightly positive association (correlation coefficient = 0.58) between malaria incidence and rainfall. A significant association between malaria incidence with average house altitude (adjusted incidence rate ratio [aIRR] 1 (95% IC 0.99-1) P < 0.001), soil type aIRR 0.54 (0.39-0.75) p < 0.001 and temperature (incidence rate ratio [IRR] 0.69 (0.66-0.73) p < 0.001).</p><p><strong>Conclusion: </strong>This study uses innovative technologies such as remote sensing and geographic information systems (GIS) to analyse the environmental, meteorological and geographical factors influencing malaria transmission, thereby identifying high-risk areas and associated factors. It demonstrates that these tools improve the accuracy of control strategies, while highlighting the crucial role of the environment and human behaviour, paving the way for more targeted interventions against malaria and other vector-borne diseases.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"157"},"PeriodicalIF":2.4,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12087215/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144094108","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":"First large-scale assessment of pyrethroid resistance in Anopheles darlingi (Diptera: Culicidae) in Brazil (2021-2024): a crucial step in informing decision-making in malaria control.","authors":"Quesia Santos Amorim, Cynara M Rodovalho, Aline C Loureiro, Priscila Serravale, Diogo F Bellinato, Patrícia Guimarães, Vincent Corbel, Ademir J Martins, José Bento Pereira Lima","doi":"10.1186/s12936-025-05385-8","DOIUrl":"10.1186/s12936-025-05385-8","url":null,"abstract":"<p><strong>Background: </strong>Malaria continues to pose a significant public health threat in northern Brazil. Current control strategies for Anopheles darlingi, the primary malaria vector in the Amazon region, depend on long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) with pyrethroid insecticides. Despite decades of insecticide use, there are very few records of pyrethroid resistance in this mosquito species in Brazil, likely due to a lack of investigations, underscoring the urgent need for further actions.</p><p><strong>Objectives: </strong>To assess the susceptibility of An. darlingi from all malaria-endemic regions in Brazil to the pyrethroids used by the Malaria Prevention and Control Programme (NMCP) for vector control.</p><p><strong>Methods: </strong>Adult females An. darlingi were collected from 28 locations in the states of Amapá, Acre, Amazonas, Pará, Rondônia, Roraima, Mato Grosso, Maranhão, and Tocantins. These locations were chosen because of their high malaria incidence in recent years. The collected mosquitoes were sent to the Laboratory of Biology, Control, and Surveillance of Insect Vectors to produce F1 progeny. Discriminating concentration (DC) WHO tube bioassays were performed on deltamethrin (0.05%), etofenprox (0.5%), and permethrin (0.75%). The intensity of resistance was evaluated by comparing the mortality rates of mosquitoes exposed to papers treated with 1 × and 5 × the DC of these insecticides.</p><p><strong>Results: </strong>Of the 19 An. darlingi populations evaluated, only four were susceptible to deltamethrin (Tapauá, Jacareacanga, Cantá, and Caracaraí). For etofenprox, 13 populations were resistant, whereas five were susceptible (Tapauá, Porto Velho, Porto Grande, Cantá, and Caracaraí). With respect to permethrin, 18 populations were evaluated, of which 12 were classified as susceptible and 6 as resistant (Coari, Manaus, Barcelos, Guajará, Rodrigues Alves, and Cruzeiro do Sul). Resistance intensity tests indicated that all populations, except Barcelos, presented low resistance to pyrethroids according to the WHO classification.</p><p><strong>Conclusions: </strong>The first large scale detection of pyrethroid resistance in An. darlingi in Brazil is concerning and calls for urgent action to prevent its spread in the Amazon region. This study represents a critical step toward establishing comprehensive resistance monitoring and management plans for malaria vectors in Brazil.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"155"},"PeriodicalIF":2.4,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12084950/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144086477","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":"Two decades of insecticide resistance in Benin: a retrospective analysis of evolution and drivers.","authors":"Steve Zinsou Hougbe, Razaki A Ossé, Roseric Azondékon, Casimir Kpanou, Minassou Juvénal Ahouandjinou, Zul-Kifl Affolabi, Koffi Djigbodi Koumodji, Hermann Sagbohan, Esdras Mahoutin Odjo, Constantin Adoha, Boulais Yovogan, Serge Akpodji, Linda Towakinou, Bruno Akinro, Albert Salako, Filémon Tokponnon, Germain Gil Padonou, Lamine Baba-Moussa, Martin Akogbeto","doi":"10.1186/s12936-025-05403-9","DOIUrl":"10.1186/s12936-025-05403-9","url":null,"abstract":"<p><strong>Background: </strong>Several studies have been conducted in Benin over the past two decades on insecticide resistance in mosquito vectors. These studies, by various authors, lead to diverse and scattered data. The present paper provides a retrospective analysis of these data to assess the current state of insecticide resistance and its evolution over two decades. Phenotypic trends were compared to mechanisms of insecticide resistance, focusing on the pyrethroids target-site mutation at codon 1014 of the voltage-gated sodium channel and the overproduction of detoxification enzymes capable of neutralizing insecticides before reaching their target.</p><p><strong>Methods: </strong>Data were collected from studies between 1996 and 1998 and from 2010 to 2024. For each selected study, the following information were extracted and organized in a Microsoft Excel spreadsheet: study year, adherence to WHO insecticide susceptibility testing protocols, mosquito species tested, study site characteristics, insecticides assessed, data source, and resistance mechanisms identified. Municipalities with data gaps exceeding five consecutive years were excluded.</p><p><strong>Results: </strong>The earliest reported cases of insecticide resistance in Benin date back to 1963, involving organochlorines. Resistance to pyrethroids was first observed in 1999, initially limited in scope. However, from 2010 to 2024, resistance to all pyrethroids spread across all regions of Benin, reaching high levels. In some municipalities, mortality rates in Anopheles gambiae sensu lato (s.l.) populations exposed to permethrin-treated papers fell below 10%. The frequency of the kdr L1014F mutation has mirrored phenotypic resistance trends, increasing from 10% homozygous resistant (kdr/kdr) individuals in 2011 to 90% in 2024 in the municipality of Allada. Detoxification enzymes, such as α-esterase, β-esterase, monooxygenase and glutathione S-transferase showed low, but steadily increasing activity between 2015 and 2024. Resistance to bendiocarb, first reported in 2012, has shown minimal progression, while resistance to pirimiphos methyl has been observed in some municipalities since 2022.</p><p><strong>Conclusion: </strong>First observed with organochlorines around the 1960s, and later with pyrethroids in 1999, insecticide resistance in mosquito vectors has continued to intensify. Over the last 20 years, it has gradually expanded, now affecting all ecological environments in Benin. In this context, the National Malaria Control Programme should prioritize the use of new mosquito nets for future vector control campaigns in Benin.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"156"},"PeriodicalIF":2.4,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12085016/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144094150","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}