Malaria Journal最新文献

{"title":"High incidence of clinical malaria among asymptomatic Plasmodium falciparum infected children receiving SMC with sulfadoxine-pyrimethamine and amodiaquine (SP + AQ) in Koulikoro, Mali.","authors":"Daouda Sanogo, Mahamoudou Toure, Moussa Keita, Fousseyni Kane, Soumba Keita, Ibrahima Sanogo, Sory Ibrahim Diawara, Cheick Oumar Tangara, Hamady Coulibaly, Bourema Cisse, Sidibé M'Baye Thiam, Mahamadou Diakite, Nafomon Sogoba, Seydou Doumbia","doi":"10.1186/s12936-025-05283-z","DOIUrl":"10.1186/s12936-025-05283-z","url":null,"abstract":"<p><strong>Background: </strong>Seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SP + AQ) involves the monthly administration of therapeutic doses to children under five years of age during periods of high risk of malaria in regions where malaria transmission is highly seasonal. Current SMC guidelines recommend administering the same treatment to both non-infected and asymptomatic Plasmodium falciparum-infected children. However, a critical knowledge gap remains the impact asymptomatic infection on the efficacy of SMC in preventing clinical malaria over a four-week period. This study aimed to evaluate the risk of clinical malaria and its association with children's infection status during SMC treatment.</p><p><strong>Methods: </strong>This study was conducted in the Koulikoro health district of Mali and focused on children under 10 years of age. A total of 726 children in 2019 and 1452 children in 2020 were randomly selected and followed throughout the SMC campaigns. The prevalence of asymptomatic P. falciparum infection was assessed in each round using microscopy prior to SMC drug administration. Children were passively monitored over a four-week period to record the incidence of clinical malaria. Data analysis was performed using R-Studio software. The risk of clinical malaria based on infection status was estimated through logistic regression analysis, and a Kaplan-Meier curve was used to compare survival times between infected and uninfected children. Proportions were compared using the Pearson Chi-square test, with statistical significance set at p < 0.05.</p><p><strong>Results: </strong>The average prevalence of asymptomatic P. falciparum infection was 11.0% across study years. Prevalence was notably higher among children aged 5 to 9 years old in 2019 (p < 0.001) and 2020 (p = 0.016). Asymptomatic infected children had a significantly higher risk of clinical malaria during both transmission seasons: 2019: (RR = 3.05, CI [2.04-4.72]) and 2020 (RR = 1.43, CI [1.04-1.97]). Furthermore, the time to the first malaria episode was significantly shorter among infected children in both years (p < 0.001 for 2019, p = 0.01 for 2020).</p><p><strong>Conclusion: </strong>These findings demonstrate an elevated risk of clinical malaria in asymptomatic infected children during SMC implementation. Screening and treating P. falciparum infections prior to SMC administration could substantially enhance the effectiveness of this strategy in reducing malaria morbidity in endemic areas.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"102"},"PeriodicalIF":2.4,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11948680/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143720122","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":"Relationship between unimproved household sanitation facilities and malaria infection among under-five children in Nigeria: insights from Malaria Indicator Survey 2021.","authors":"Olamide A Asifat, Adedeji Adenusi, Tolulope V Adebile, Nicholas Aderinto, Emmanuel Azu, Adverlyn Ivey-Waters, Jing X Kersey","doi":"10.1186/s12936-025-05340-7","DOIUrl":"10.1186/s12936-025-05340-7","url":null,"abstract":"<p><strong>Background: </strong>Malaria is a leading cause of illness and death among children under-five in sub-Saharan Africa, with Nigeria bearing the highest global malaria burden. Despite interventions such as insecticide-treated nets and indoor residual spraying, malaria prevalence remains high. While housing structure and sanitation are recognized as risk factors in other African countries, their relationship with malaria infection among under-five children in Nigeria remains underexplored. This study investigates this association using nationally representative data from the 2021 Nigeria Malaria Indicator Survey (NMIS).</p><p><strong>Methods: </strong>This study analysed data from the 2021 NMIS, including 1833 children aged 5-59 months (weighted sample size: 1,784,805,486) tested for malaria using rapid tests. Data on malaria prevention practices, household characteristics, and children's blood samples were collected. The primary outcome was malaria test results (rapid diagnostic test, RDT), with the type of toilet facility as the main predictor. Covariates included age, sex, wealth index, maternal education, residence type, household construction materials, drinking water sources, type of mosquito nets, and mosquito net usage. Descriptive statistics and logistic regression analyses were conducted to assess associations, reporting adjusted odds ratios (aORs), 95% confidence intervals (CIs), and p-values < 0.05.</p><p><strong>Results: </strong>Children from the poorest (aOR = 3.412, 95% CI: 1.798-6.477, p = 0.0002) and poorer households (aOR = 3.103, 95% CI: 1.714-5.617, p = 0.0002) had significantly higher malaria risk. Rural residence (aOR = 1.898, 95% CI: 1.318-2.734, p = 0.0006) and no maternal education (aOR = 2.003, 95% CI: 1.153-3.480, p = 0.0139) were also associated with increased malaria prevalence. Additionally, unimproved wall materials (aOR = 1.604, 95% CI: 1.061-2.425, p = 0.025) increased malaria risk. However, unimproved sanitation facilities were not significantly associated with malaria risk (p = 0.166).</p><p><strong>Conclusion: </strong>Malaria risk among under-five children in Nigeria is strongly associated with socioeconomic factors, rural residence, and maternal education, but not unimproved sanitation alone. Efforts to reduce malaria prevalence should target broader social determinants through health education and socioeconomic interventions in Nigeria and other endemic regions.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"103"},"PeriodicalIF":2.4,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11948688/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143730734","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":"False alarm on a malaria \"outbreak\" linked to inconsistencies in malaria diagnostic supply: a call to strengthen supply chain management: Sierra Leone, May-July 2023.","authors":"Timothy N DeVita, Aminata B Kabia, James A M Khobi, Mugagga Malimbo, Samba Kamara, Bridget Magoba, Gebrekrstos N Gebru, Anna H Jammeh, John A Painter, Thomas K Ansumana, Musa Sillah-Kanu, David C Schnabel","doi":"10.1186/s12936-025-05312-x","DOIUrl":"10.1186/s12936-025-05312-x","url":null,"abstract":"<p><strong>Background: </strong>Malaria transmission in Sierra Leone is intense and perennial, accounting for 40% of clinical consultations. Medical workers diagnose suspected malaria cases using rapid diagnostic tests (RDT) and microscopy, with facility-level results reported to the Health Management Information System (HMIS) as monthly aggregates. Commodity stocks are reported to the Logistics Management Information System (LMIS). Partners investigated a striking increase in confirmed malaria during May-July 2023 in Sierra Leone, peaking in June to 46% above the June 2018-2022 mean.</p><p><strong>Methods: </strong>The team first analysed national, district, and facility HMIS/LMIS data for RDT stocks, testing rates, and confirmed cases during January 2018-October 2023. Epidemic thresholds, defined as case counts two standard deviations (σ) above the previous 5 years' monthly mean, were assessed. Then four facilities in two districts were visited to interview staff. Lastly, the team reanalysed LMIS RDT stock data for all facilities in Sierra Leone using R to categorize their stock status by month.</p><p><strong>Results: </strong>National epidemic thresholds were surpassed in May (2.56σ) and June (4.81σ) 2023. Twelve of sixteen districts surpassed epidemic thresholds during May-June. Investigation revealed inconsistent RDT distribution to facilities over time. National RDT distribution spiked in May 2023, when 551,888 RDT test kits were delivered. This was substantially larger than the 2019-2022 mean for May (53,121, 1,000% increase) and all months (126,866, 435% increase). Subsequently in June 2023, 386,343 tests were performed, 36% higher than the June 2018-2022 mean (285,123). Staff at all four visited facilities reported recurrent RDT stockouts. The proportion of facilities in Sierra Leone reporting positive RDT stocks at both the start and end of the month increased from 14% in April to 74% in June. 51% of facilities began May with RDT stockout and received RDTs that month.</p><p><strong>Conclusions: </strong>The 2023 spike in confirmed malaria was likely related to increased testing following an unusually large distribution of RDTs. Fluctuations in RDT availability impede the ability to recognize true case variations. Sierra Leone and its partners can strengthen supply chain logistics and health commodity stock tracking to ensure a consistent supply of RDTs and improve interpretation of surveillance data.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"100"},"PeriodicalIF":2.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11948700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143720120","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 subpatent Plasmodium falciparum infections in regions with varying transmission intensities and implications for malaria elimination in Mainland Tanzania.","authors":"Misago D Seth, Zachary R Popkin-Hall, Rashid A Madebe, Rule Budodo, Catherine Bakari, Beatus M Lyimo, David Giesbrecht, Ramadhani Moshi, Ruth B Mbwambo, Filbert Francis, Dativa Pereus, Doris Mbata, Daniel P Challe, Salehe S Mandai, Gervas A Chacha, Angelina J Kisambale, Daniel Mbwambo, Sijenunu Aaron, Abdallah Lusasi, Samwel Lazaro, Celine I Mandara, Jeffrey A Bailey, Jonathan J Juliano, Julie R Gutman, Deus S Ishengoma","doi":"10.1186/s12936-025-05341-6","DOIUrl":"10.1186/s12936-025-05341-6","url":null,"abstract":"<p><strong>Background: </strong>Subpatent Plasmodium falciparum infections, defined as infections with parasite density below the detection limit of routine malaria diagnostic tests, contribute to infectious reservoirs, sustain transmission, and cause the failure of elimination strategies in target areas. This study assessed the prevalence of subpatent P. falciparum infections and associated risk factors in 14 regions of Mainland Tanzania.</p><p><strong>Methods: </strong>The study used samples randomly selected from RDT-negative dried blood spots (DBS) (n = 2685/10,101) collected in 2021 at 100 health facilities across 10 regions of Mainland Tanzania, and four communities in four additional regions. The regions were selected from four transmission strata; high (five regions), moderate (three regions), low (three regions), and very low (three regions). DNA was extracted by Tween-Chelex method, and the Pf18S rRNA gene was amplified by quantitative polymerase chain reaction (qPCR). Logistic regression analysis was used to assess the associations between age groups, sex, fever status, and transmission strata with subpatent infection status, while linear regression analysis was used to assess the association between these factors and subpatent parasite density.</p><p><strong>Results: </strong>Of the selected samples, 525/2685 (19.6%) were positive by qPCR for P. falciparum, and the positivity rates varied across different regions. Under-fives (aOR: 1.4, 95% CI 1.04-1.88; p < 0.05) from health facilities had higher odds of subpatent infections compared to other groups, while those from community surveys (aOR: 0.33, 95% CI 0.15-0.72; p = 0.005) had lower odds. Participants from very low transmission stratum had significantly lower odds of subpatent infection compared to those from high transmission stratum (aOR = 0.53, 95% CI = 0.37-0.78; p < 0.01). The log-transformed median parasite density (interquartile range) was 6.9 (5.8-8.5) parasites/µL, with significantly higher parasitaemia in the low transmission stratum compared to a very low one (11.4 vs 7.0 parasites/µL, p < 0.001).</p><p><strong>Conclusion: </strong>Even in very low transmission settings, the prevalence of subpatent infections was 13%, and in low transmission settings it was even higher at 29.4%, suggesting a substantial reservoir that is likely to perpetuate transmission but can be missed by routine malaria case management strategies. Thus, control and elimination programmes may benefit from adoption of more sensitive detection methods to ensure that a higher proportion of subpatent infections are detected.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"101"},"PeriodicalIF":2.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11948789/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143720140","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":"Coinfection of COVID-19 and malaria: clinical profiles, interactions, and strategies for effective control.","authors":"Mu-Zi He, Hai-Ting Zhang, Yi Yang, Yi Fang, Mao Zhang, Sheng-Qun Deng, Xun Sun","doi":"10.1186/s12936-025-05315-8","DOIUrl":"10.1186/s12936-025-05315-8","url":null,"abstract":"<p><p>Since SARS-CoV-2 has caused unprecedented changes in the epidemiology of other infectious diseases, investigations on coinfection between SARS-CoV-2 and one of the famous vector-borne diseases, malaria, are crucial for disease control, especially in malaria-endemic areas. The clinical profiles, possible mechanisms for interactions, and representative control measures of COVID-19 and malaria coinfections have recently garnered public attention. The overlap in epidemiology, infection incubation, and clinical symptoms between COVID-19 and malaria coinfections has been thoroughly discussed to provide a detailed diagnostic procedure for coinfections, thereby guiding appropriate clinical interventions. Immunological and genetic evidence has shown that previous malaria exposure may protect the body from the poor prognosis of COVID-19. ACE2 downregulation and TLR-induced pathways play a role in this protective effect, as do CD8 + and CD4 + T-cell activation and coinhibitory receptor upregulation, which help maintain a balance of immune reactions. Finally, multiple control measures for coinfections were discussed, and malaria control efforts were enriched in the context of COVID-19. These efforts included (1) developing vaccinations; (2) evaluating the efficacy of anti-malarial drugs in the SARS-CoV-2 treatment; (3) exploring recent advances in natural products that are potentially useful for coinfection treatment; (4) researching and implementing bioinsecticides for malaria control, such as gene-driven mosquitoes, fungi, and bacterial symbionts; and (5) improving national electronic disease surveillance platforms in malaria-endemic regions. At last, the above findings summarized valuable lessons about malaria and COVID-19 control and expedite further investigations on coinfections with complex clinical presentations.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"99"},"PeriodicalIF":2.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11938571/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143710609","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":"Community pharmacists' knowledge and experience regarding malaria management: a cross-sectional study in Hodeida, Yemen.","authors":"Abdulsalam M Halboup, Sabariah Noor Harun, Siti Maisharah Sheikh Ghadzi, Syed Azhar Syed Sulaiman, Doa'a Anwar Ibrahim, Abdullah Ahmed Areqi, Fahmi Y Al-Ashwal","doi":"10.1186/s12936-025-05291-z","DOIUrl":"10.1186/s12936-025-05291-z","url":null,"abstract":"<p><strong>Background: </strong>Malaria remains a significant public health concern in Yemen, ranking fourth in incidence within the Eastern Mediterranean Region. Community pharmacists play a pivotal role in malaria management and often dispense anti-malarial medications without prescriptions. However, little is known about their knowledge and adherence to the National Policy for Antimalarial Drugs. This study aimed to evaluate pharmacists' knowledge, experience, and perceived barriers regarding malaria management in Hodeidah, Yemen.</p><p><strong>Methods: </strong>A cross-sectional study was conducted between May and August 2023 across 320 community pharmacies in 16 districts of Hodeidah governorate. A validated questionnaire was used to assess pharmacists' knowledge, experience, and perceived barriers to effective malaria management. Descriptive statistics and logistic regression analysed the associations between sociodemographic factors and pharmacists' knowledge and experience.</p><p><strong>Results: </strong>Of the 304 respondents, 10 were excluded due to incomplete data, yielding a valid response rate of 91.9% (294). Most pharmacies were independent (74.8%), and 51.4% were located in Hodeidah city. The majority of the pharmacists were male (92.2%), aged 19-30 years (50.3%), and held a pharmacy diploma (69%). Poor knowledge of malaria management was observed in 76.5% of respondents (mean: 9.96, SD 3.47), with only 34.4% and 43.2% accurately identifying first-line treatments for uncomplicated and complicated malaria, respectively. Additionally, 60.9% were aware of the prevalent malaria species, and 53.1% knew the correct diagnostic methods. However, only 17.0% recognized high-risk groups for complicated malaria, 18.4% identified causes of treatment failure, and 7.8% understood the consequences of malaria during pregnancy. In terms of experience, 76.2% of the participants reported inadequate experience related to anti-malarial medications (mean: 56.71, SD 7.32), with the main barriers being lack of training (78.9%) and insufficient knowledge (73.5%). Multivariable logistic regression revealed that older age (AOR: 6.827, p = 0.020), holding a pharmacy diploma (AOR: 2.555, p = 0.036), and fewer perceived barriers (AOR = 3.830, p < 0.001) were predictors of poor knowledge, whereas practicing in Hodeidah city (AOR = 1.865, p = 0.043) predicted inadequate experience.</p><p><strong>Conclusion: </strong>Community pharmacists in Hodeidah demonstrate significant gaps in knowledge and experience related to malaria management. Urgent educational interventions are needed to enhance pharmacists' competency, ensure effective malaria treatment, and prevent the emergence of drug resistance in Yemen.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"98"},"PeriodicalIF":2.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11934465/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143710610","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":"Genetic diversity and population structure of Plasmodium falciparum across areas of varied malaria transmission intensities in Uganda.","authors":"Alex Mwesigwa, Stephen Tukwasibwe, Bryan Cummings, Hakiimu Kawalya, Shahiid Kiyaga, Stephen Okoboi, Barbara Castelnuovo, Everd Maniple Bikaitwoha, Joan N Kalyango, Samuel L Nsobya, Charles Karamagi, Pauline Byakika-Kibwika, Joaniter I Nankabirwa","doi":"10.1186/s12936-025-05325-6","DOIUrl":"10.1186/s12936-025-05325-6","url":null,"abstract":"<p><strong>Background: </strong>Malaria remains a significant global health threat, with sub-Saharan Africa (SSA) bearing the highest burden of the disease. Plasmodium falciparum is the predominant species in the region, leading to substantial morbidity and mortality. Despite intensified control efforts over the last two decades, P. falciparum genetic diversity and multiplicity of infections (MOI) continue to pose significant challenges to malaria elimination in the region. This study assessed P. falciparum genetic diversity and population structure in areas with low, medium, and high malaria transmission intensities in Uganda.</p><p><strong>Methods: </strong>A total of 288 P. falciparum-positive samples from children (6 months to 10 years) and adults (≥ 18 years) living in Jinja (low transmission), Kanungu (medium transmission), and Tororo (high transmission) were genotyped using seven neutral microsatellite markers. Genetic diversity was assessed based on the number of alleles (N_a), allelic richness (Ar), and expected heterozygosity (H_e). Population structure was assessed using the fixation index, analysis of molecular variance (AMOVA), and clustering analysis.</p><p><strong>Results: </strong>High P. falciparum genetic diversity was observed across all study sites, with Kanungu exhibiting the highest mean H_e (0.81 ± 0.14), while Jinja and Tororo had lower mean H_e (0.78 ± 0.16). P. falciparum MOI varied significantly, with Tororo showing the highest mean MOI (2.5 ± 0.5) and 70% of samples exhibiting polyclonal infections, compared to Jinja's mean MOI of 1.9 ± 0.3 and 58% polyclonal infections. Significant multilocus linkage disequilibrium (LD) was noted (p < 0.01), ranging from 0.07 in Tororo to 0.14 in Jinja. Parasite population structure showed minimal genetic differentiation (F_ST ranged from 0.011 to 0.021) and a low AMOVA value (0.03), indicating high gene flow.</p><p><strong>Conclusion: </strong>This study demonstrates high P. falciparum genetic diversity and MOI but low population structure, suggesting significant parasite gene flow between study sites. This highlights the need for integrated malaria control strategies across areas with varying malaria transmission intensities in Uganda.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"97"},"PeriodicalIF":2.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11934718/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143700555","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":"Identifying gaps in protection from malaria vector biting in rural Cambodia using an entomological assessment and human behaviour observations.","authors":"David J McIver, Elodie A Vajda, Dyna Doum, Nicholas W Daniel, Molly Quan, Diane D Lovin, Joanne M Cunningham, Siv Sovannaroth, Allison Tatarsky, Neil F Lobo","doi":"10.1186/s12936-025-05304-x","DOIUrl":"10.1186/s12936-025-05304-x","url":null,"abstract":"<p><strong>Background: </strong>Forest-exposed populations remain the last significant, and most difficult to access, high-risk populations for malaria in Cambodia. Despite the availability of long-lasting insecticidal nets (LLINs) and/or hammock nets (LLIHNs), continued malaria transmission indicates gaps in protection. This study aimed to identify these gaps among forest-exposed individuals in Plasmodium falciparum hotspots in two provinces in Cambodia, using entomological assessments and human behaviour observations (HBOs).</p><p><strong>Methods: </strong>Anopheles bionomic traits were characterized using Human Landing Catches (HLCs) in a village setting in Mondulkiri province, and in both village and forest settings in Kampong Speu province, Cambodia. Mosquitoes were collected from 17h00 to 07h00 over 540 collection nights. Human behaviour observations (HBOs) focused on monitoring activities near HLC sites and recording the use of LLINs/LLIHNs or Project BITE's bite prevention tools: a volatile pyrethroid spatial repellent (VPSR), topical repellent (TR), and insecticide-treated clothing (ITC). Data on mosquito landing pressure and human behaviours were integrated to generate the HBO-adjusted Human Landing Rate (HBO-adjusted HLR).</p><p><strong>Results: </strong>A total of 5,985 Anopheles mosquitoes were collected, with 608 (10%) identified molecularly to species-level. Seventeen Anopheles species were identified, including a likely novel species from the Leucosphyrus Subgroup, which was the predominant species characterized. The HBO-adjusted HLR was found to be greatest during the early evening hours, when people were outdoors awake, followed by when people were sleeping indoors without a net. Relatively few people were observed using, or correctly using, the new bite prevention tools intended for protection in the forest.</p><p><strong>Conclusion: </strong>This study demonstrates the importance of understanding spatial and temporal human exposure to mosquito bites, in the presence of proven vector control tools (LLINs, LLIHNs) and newly introduced bite prevention tools (VPSRs, ITCs, and TRs). To help achieve malaria elimination, human behaviour data on intervention use and behaviour patterns should be evaluated and integrated with entomological data towards identifying and quantifying protection conferred by current interventions, as well as remaining gaps in protection. This information supports the selection of appropriate interventions, which supplement rather than replace existing tools, to target existing gaps in protection.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"96"},"PeriodicalIF":2.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11934795/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143700594","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 variation of Microsporidia MB infection in Anopheles gambiae and Anopheles coluzzii in two different geographical localities in Benin.","authors":"Genevieve Tchigossou, Michel Lontsi-Demano, Eric Tossou, Pierre-Marie Sovegnon, Romaric Akoton, Danahe Adanzounon, Camille Dossou, Massioudou Koto, Azarath Ogbon, Marie Gouété, Godfrey Nattoh, Rousseau Djouaka","doi":"10.1186/s12936-025-05247-3","DOIUrl":"10.1186/s12936-025-05247-3","url":null,"abstract":"<p><strong>Background: </strong>Microsporidia MB, a naturally occurring Anopheles symbiont was shown to strongly impair Plasmodium transmission without imposing deleterious fitness effects on larval development, fecundity, adult survival, and adult sex ratio, and for these reasons it is being proposed as a promising tool for malaria control. However, there is a limited knowledge about its ecology, transmission dynamics in the environments with varying abiotic conditions, and whether these could impact on the mode of host transmission. This study aimed to determine the presence and prevalence of Microsporidia MB in rice fields in Benin during both the dry and wet seasons.</p><p><strong>Methods: </strong>Anopheles larvae and adults were collected from rice fields and houses around rice fields in two locations (Koussin-Lélé and Magoumi). The collections took place during both the dry and wet seasons. The larvae and adults were molecularly identified to species level using molecular techniques and they were also screened for the presence of Microsporidia MB using PCR following standard protocols. Moreover, breeding sites were also analysed.</p><p><strong>Results: </strong>The species identification results revealed that Anopheles coluzzii was the main species in Koussin-Lélé, accounting for 100% of the 1718 samples, while Anopheles gambiae sensu stricto (s.s.) was predominant in Magoumi accounting for 98.17% of the 986 samples. In Koussin-Lélé, Microsporidia MB prevalence of 14% (n = 276) was observed, whereas in Magoumi, only two samples (0.3%) were tested positive out of 667 screened in the dry season. During the wet season, the prevalence of Microsporidia MB symbiont was low with rates of 0.7% (5) in Koussin-Lélé and 0.6% (8) in Magoumi. However, the prevalence was relatively moderate in adult field collected mosquitoes with 3.09% (n = 1554) followed by larvae samples with 2.93% (n = 682) and adults emerged from field-collected larvae with 2.67% (n = 1235). Analysis of breeding sites revealed high concentrations of nitrate, nitrite and copper in Magoumi during the dry season, which was associated with a low prevalence of Microsporidia MB symbiont in this area. In the wet season, high concentrations of lead and nitrate were recorded in Koussin-Lélé with high concentration of copper in Magoumi, and both localities showed low prevalence of Microsporidia MB infection.</p><p><strong>Conclusion: </strong>This study revealed a high prevalence of Microsporidia MB symbiont in Benin during the dry season. Further investigations might be necessary, and modelling of the prevalence and characteristics of breeding sites could help predict the presence of this symbiont in other locations and countries.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"95"},"PeriodicalIF":2.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11931768/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143692704","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":"WHO malaria nucleic acid amplification test external quality assessment scheme: results of eleven distributions over 6 years.","authors":"Rebecca M Thomson, Jane A Cunningham, Michelle M Gatton, Sean C Murphy, Maria de la Paz Ade, Xavier C Ding, Sandra Incardona, Eric Legrand, Naomi Lucchi, Didier Menard, Samuel L Nsobya, Agatha C Saez, Jaya Shrivastava, Peter L Chiodini","doi":"10.1186/s12936-025-05282-0","DOIUrl":"10.1186/s12936-025-05282-0","url":null,"abstract":"<p><strong>Background: </strong>The World Health Organization (WHO) recommends parasite-based diagnosis of malaria before treatment. The use of nucleic-acid amplification (NAAT) for detection of Plasmodium spp. has expanded rapidly in recent years, for epidemiological research globally and clinical care in high-resource settings. Data from NAATs are frequently used to inform policy decisions, so quality control is essential to ensure results are reliable and comparable. Therefore, robust quality control, including an external quality assessment (EQA) scheme targeting malaria NAATs, is essential. The WHO Global Malaria Programme and the UK National External Quality Assessment Service (UK NEQAS) have collaborated since 2017 to implement a global malaria NAAT EQA scheme.</p><p><strong>Methods: </strong>Panels of specimens containing five major species of human-infecting Plasmodium at various parasite concentrations and negative samples were created in lyophilized blood (LB) and dried blood spot (DBS) formats. Two distributions per year were sent, containing five LB and five DBS specimens. Samples were validated by expert referee laboratories prior to distribution. Between 37 and 51 laboratories participated in each distribution and submitted results online. Participants were scored based on their laboratory's stated capacity to identify Plasmodium species, and individual laboratory reports were sent which included performance comparison with anonymized peers. Change in performance over time was calculated using a generalized mixed model with a logit link function.</p><p><strong>Results: </strong>Participating laboratories were located in 42 countries. Sample format (DBS or LB) and parasite density were found to significantly affect performance, while referee labs performed better at identifying P. falciparum samples than non-referee labs. Performance of laboratories improved significantly over time, especially for lower density and P. falciparum samples.</p><p><strong>Conclusions: </strong>Results from the first eleven distributions indicate that the EQA scheme has facilitated improved performance of laboratories over time, highlighting the value of implementing such programmes. EQA schemes are critical to safeguarding the reliability of data and diagnoses, especially in situations where NAAT methodologies and protocols are used. In future, funders should make participation in an EQA scheme a requirement for laboratories, and countries can take initiatives to embed such schemes into their own national assessment programmes.</p>","PeriodicalId":18317,"journal":{"name":"Malaria Journal","volume":"24 1","pages":"94"},"PeriodicalIF":2.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11929988/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143692706","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}