Malaria Journal最新文献

Background: Malaria remains a critical public health challenge globally, particularly in sub-Saharan Africa where it significantly contributes to morbidity and mortality among children under-five. In Ghana, efforts to promote the use of insecticide-treated nets (ITNs) as a preventive measure have been substantial but utilization rates remain suboptimal. This study examines the influence of caregivers' malaria-related knowledge on ITN use among children under the age of five years in a rural district of Ghana.

Methods: A community-based cross-sectional study was conducted in the Ahafo Ano South West District, Ghana, between June and October 2023. A total of 442 caregivers (mothers) of children under-five were selected using a two-stage sampling process. Data were collected through structured interviews and analysed using bivariate and multivariable logistic regression models to determine the association between caregivers' malaria-related knowledge and ITN use among children.

Results: Out of 442 caregivers, 436 (98.6%) completed the survey. ITN use among children under-five the night before the survey was reported by 73.8% of caregivers. Overall, 36.8% of caregivers had good malaria-related knowledge, 41.2% had satisfactory knowledge, and 21.9% had poor knowledge. Multivariable analysis showed that caregivers with good malaria-related knowledge were 12 times more likely to use ITNs for their children (AOR = 12.06, 95% CI 2.30-53.20) compared to those with poor knowledge. Other significant predictors included education on ITN use, ITN ownership, child's age, and use of alternative malaria prevention methods.

Conclusion: This study highlights the critical role of caregiver malaria-related knowledge in promoting ITN use among children under-five in rural Ghana. Caregivers with better knowledge were significantly more likely to use ITNs, emphasizing the need for targeted health education programs. Such interventions should enhance awareness of malaria risks and ITN benefits, empower caregivers to use ITNs effectively, and reduce barriers to ITN access. These findings provide valuable insights for policymakers aiming to improve ITN utilization and reduce malaria morbidity and mortality in vulnerable populations.

Background: Insecticide-based malaria vector control has been implemented on the islands of São Tomé and Príncipe (STP) for more than 20 years. During this period malaria incidence was significantly reduced to pre-elimination levels. While cases remained low since 2015, these have significantly increased in the last year, challenging the commitment of the country to achieve malaria elimination by 2025. To better understand the reasons for increasing malaria cases, levels and underlying mechanisms of insecticide resistance in the local Anopheles coluzzii populations were characterized.

Methods: Mosquito larval collections were performed in the rainy and dry seasons, between 2022 and 2024, in two localities of São Tomé and one locality in Príncipe. Susceptibility to permethrin, α-cypermethrin, pirimiphos-methyl and DDT was assessed using WHO bioassays and protocols. Intensity of resistance and reversal by PBO pre-exposure were determined for pyrethroid insecticides. The kdr locus was genotyped by PCR assays in subsamples of the mosquitoes tested.

Results: Anopheles coluzzii populations were fully susceptible to pirimiphos-methyl, but high levels of resistance to pyrethroids and DDT were detected, particularly in São Tomé rainy season collections. Increasing the pyrethroid and DDT dosages to 5 $\times$ and 10 $\times$ did not restore full susceptibility in all populations. Pre-exposure to PBO resulted into partial reversal of the resistance phenotype suggesting the presence of cytochrome P450 oxidases-mediated metabolic resistance. The L1014F knockdown resistance mutation was present in An. coluzzii on both islands but at much higher frequency in São Tomé where it was associated with the resistant phenotype.

Conclusions: Future vector control interventions should consider the use of non-pyrethroid insecticides or combination with synergists to overcome the high levels of pyrethroid resistance. Alternative control methods not dependent on the use of insecticides should be additionally implemented to achieve malaria elimination in STP.

Background: Approximately 70% of the Kenyan population is at risk for malaria, including 19 million people in highland epidemic-prone and seasonal transmission areas. Surveillance data showed a 288% increase in malaria cases and an incidence rate of 10.5 per 1000 population between January and May 2021 in Nandi County. We investigated the increased incidence of malaria in Nandi County.

Methods: We abstracted demographic and clinical data from the laboratory register in health facilities with high malaria burden. Key informant interviews using a structured questionnaire collected healthcare worker perceptions on malaria interventions and personnel capacity. We calculated means and medians for continuous variables and frequency and proportions for categorical variables. Data quality assessment (DQA) was conducted to evaluate timeliness and completeness, data accuracy, and overall system assessment.

Results: We reviewed 19,526 records from 12 health facilities. Females contributed 61% cases (11,862). A majority of cases, 21% (4111), were between the age group 15-24 years. Of the 19,498 tested, 2662 tested positive (test positivity rate, TPR = 13.7%). Microscopy accounted for 39% (1041) and RDT for 61% (1620) of tests conducted, with some patients being double tested using both tests. Kapsabet County Referral contributed 26% (5051) suspected cases, TPR 3.2%, and Chemase Health Centre TPR was 33.2%. Facilities experienced major RDTs stock-outs in the preceding 3 months while three (30%) of the 10 facilities assessed conducted laboratory Internal Quality Control (IQC) programmes. Of the 12 facilities assessed, four (33%) facilities had an over-reporting of suspected cases in the monthly summary, while three (25%) facilities were over-reported in the online tool. On reporting confirmed malaria cases, over-reporting was noted in three (25%) facilities in both the monthly summaries and the online tool. Data completeness was 77% and timeliness 93%.

Conclusion: The increase in malaria cases in Nandi County displayed a seasonal pattern that coincided with either the long or short rainy seasons, the investigation did not reveal an active outbreak at the time of the inquiry. Sub-county hospitals in Tinderet and Aldai sub-counties had malaria cases exceeding both the alert and action thresholds at specific times during the year under review, suggesting a potential occurrence of unidentified outbreaks, while several other facilities had an increase of cases reaching alert thresholds, indicating upsurges. In healthcare settings, we noted there were problems with data quality. We advised routine data review, analysis, and feedback; mentorships for data analysis and on the job and support supervision; mentorships for malaria diagnosis; and installation of laboratory quality assurance.

Background: The 1-3-7 approach to eliminate malaria was first implemented in China in 2012. It has since been expanded to multiple countries, but no systematic review has examined the evidence for its use. A systematic review was conducted aiming to evaluate the impact and effectiveness of the strategy and identify key challenges and variations in its implementation across different countries.

Methods: PUBMED, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CABS Abstracts, LILACS, Global Health, Medrxiv, Biorxiv were searched for all studies containing 1-3-7 and articles included if they contained information on 1-3-7 impact, effectiveness, challenges and/or adaptations for implementation in different countries.

Results: 31 studies were included from China (19), Thailand (6), Myanmar (2), Tanzania (1), Cambodia (1), India (1) and Vietnam (1). During 1-3-7 implementation, malaria cases in China decreased by 99.1-99.9%, in Thailand by 66.9% during 2013-19, 65,1% in Cambodia during 2015-17 and 30.3% in India during 2015-16, with some differences in implementation. It was not possible to separate the impact of 1-3-7 from that due to other contemporaneous interventions. Implementing the 1-3-7 policy was largely effective, with reporting within 1 day in 99.8-100% of individuals in China and 36-100% in other countries, investigation within 3 days in 81.5-99.4% in China and 79.4-100% in other countries, and foci investigation within 7 days in 90.1-100% in China and 83.2-100% in other countries. Adaptations to 1-3-7 were described in 5 studies, mostly adjustment of the timing and/or definitions of each component. Key challenges identified included those related to staffing, equipment, process, and patient-provided information.

Conclusion: Overall, the 1-3-7 approach was effectively implemented with a concomitant decrease in cases in malaria elimination settings, however, it was not possible to quantify impact as it was not implemented in isolation. Implementing adequate measures for testing, reporting, treatment, and containment is crucial for its success, which is dependent on the availability of resources, infrastructure, staffing, and consistent compliance across regions and throughout the year. However, achieving this nationally and maintaining compliance, especially at borders with malaria-affected countries, poses significant challenges.

Background: Implemented in 17 countries to date, seasonal malaria chemoprevention (SMC) is a recommended strategy to prevent childhood malaria in areas with seasonal transmission of P. falciparum through monthly administration of antimalarial medicines. Understanding the costs and resource requirements of SMC delivery is necessary for effective planning and resource allocation. This systematic literature review aims to assess the evidence on the cost and cost-effectiveness of SMC delivery.

Methods: Following PRISMA guidelines, five databases were systematically reviewed to identify evidence on SMC costs and cost-effectiveness published between 2012 and 2023. Studies with defined costing methodologies and cost output measures were included, excluding those relying solely on mathematical modeling. Two reviewers assessed each study for eligibility and extracted cost data, which were adjusted for inflation. Quality assessment was completed using the CHEERS checklist.

Results: Six costing studies were identified spanning nine countries. Four studies examined costs during an SMC pilot or introduction, one during scale-up, and one costed newly established SMC campaigns through a multi-country project. Costs were examined at country level with the financial costs per child receiving a full course of SMC ranging from $1.71 to $12.46, while economic costs per child ranged from $2.11 to $29.06. Four studies included a cost effectiveness analysis with incremental cost-effectiveness ratios (ICERs) per clinical malaria case averted ranging from $5.41 to $138.03; ICER per disability-adjusted life year (DALY) averted from $24.51 to $182.88; and ICER per death averted from $688.86 to $18,418.81. Differences in cost estimates stemmed from different factors including variations in cost ingredients, scale of the intervention, and study perspectives.

Discussion: The level of detail for reporting SMC costs and cost categories varied greatly by study as did the scale of intervention, limiting comparability as well as an understanding of the complete costs and resource requirements for SMC implementation. Cost evidence is not from mature programs but from pilots or relatively new campaigns. Costs incurred by households and costs of the integrated delivery of SMC with other health interventions were often overlooked. Adopting a standardized costing approach for mature SMC programmes could provide a better understanding of resource requirements and costs while enhancing study comparability across settings, better informing future resource allocation and improving efficiency.

Background: Placental malaria (PM) is characterized by Plasmodium parasite sequestration in the placenta. It is responsible for various adverse pregnancy outcomes, including maternal anaemia and low birth weight (LBW). This study aimed to assess prevalence and risk factors of PM, and gestational malaria (GM), together with the prevalence of congenital malaria (CM), maternal anaemia, and LBW among parturient women attending delivery ward of Metti Health Centre (Metti HC) in Majang Zone of Gambella Region, Southwest Ethiopia.

Methods: A cross-sectional study involving 180 parturient women attending delivery ward of Metti HC was conducted from November 2022-March 2023. Sociodemographic, obstetric, and anti-malarial intervention data were collected. Capillary, placental and cord blood, and placental biopsy were collected to diagnose malaria using rapid diagnostic test (RDT), microscopy, quantitative polymerase chain reaction (qPCR), and histopathology. Haemoglobin concentration and blood group of the mother and weight of the newborn were determined. Statistical analyses were done by SPSS Version 26.0. Multivariable logistic regression analysis and Chi-square test were done to identify risk factors. Results were presented in text, tables and graphs.

Results: The prevalence of GM, PM, CM, maternal anaemia, and LBW was 24.4% (95% CI 18.1-30.1), 34.4% (95% CI 27.4-41.4), 5.0% (95% CI 2.4-8.8), 41.7% (95% CI 34.6-49.0) and 27.8% (95% CI 21.6-34.6), respectively. Risk factors of GM were: presence of malaria history within the previous year (AOR: 5.10; 95% CI 1.64-15.83), lack of indoor residual spray (IRS) within the previous year (AOR: 2.98; 95% CI 1.05-8.45), and lack of antenatal care (ANC) contact during the index pregnancy (AOR: 3.96; 95% CI 1.44-10.87). Risk factors of PM were: presence of malaria history within the previous year (AOR: 2.98; 95% CI 1.05-8.45), and lack of ANC contact during the index pregnancy (AOR: 4.83; 95% CI 1.91-12.18). The risk of CM (p < 0.001), maternal anaemia (p < 0.001) and LBW (p < 0.001) increased with GM and PM.

Conclusion: There is high prevalence of GM, PM, maternal anaemia, and LBW in the study area. The presence of GM and PM increased the risk of maternal anaemia, CM, and LBW. The identified risk factors should be considered to mitigate malaria among parturient women and its adverse outcomes.

Background: Seasonal malaria chemoprevention (SMC) refers to monthly administration of full treatment courses of anti-malarial medicine to children <5 years during high malaria transmission seasons. SMC has demonstrated effectiveness in Sahel and sub-Sahel countries in Africa. However, it was not implemented in Uganda until April 2021, when the country began SMC in the highly malaria-endemic Kotido and Moroto Districts. This study assessed the effect of SMC on malaria incidence among children <5 years of age in Kotido and Moroto Districts.

Methods: An interrupted time-series analysis was conducted using monthly national health data from the Uganda Ministry of Health District Health Information System 2. The monthly data for outpatient (uncomplicated) malaria among children <5 years was extracted for the 52 months before SMC implementation (Jan 2017-Apr 2021) and 8 months during SMC implementation (May-Dec 2021). The monthly incidence of uncomplicated malaria per 1000 children <5 years was computed before and during SMC implementation.

Results: In Kotido District, malaria incidence was 693/1000 during SMC implementation period, compared to an expected 1216/1000 if SMC had not been implemented. The mean monthly malaria incidence was 87/1000, compared to an expected mean of 152/1000 if SMC had not been implemented. This represents a statistically significant mean monthly change of -65.4 (95% CI = -104.6, -26.2) malaria cases/1000 during SMC implementation, or a 43.0% decline. In Moroto District, malaria incidence was 713/1000 during SMC implementation period, compared to an expected 905/1000 if SMC had not been implemented. The mean monthly malaria incidence was 89/1000, compared to an expected 113/1000 if SMC had not been deployed. This represents a statistically significant mean monthly change of -24.0 (95% CI = -41.1, -6.8) malaria cases/1000 during SMC implementation, or a 21.2% decline.

Conclusion: Implementation of SMC substantially reduced the incidence of uncomplicated malaria among children <5 years in Moroto and Kotido Districts. Scaling up SMC in other districts with high malaria transmission could reduce malaria on a large scale across Uganda.

Background: Malaria remains a significant public health concern, despite global efforts to combat the disease with highest burden in Africa. Reports of emerging artemisinin partial- resistance in East Africa emphasize the importance of molecular data to guide policy decisions. Hence the need for researchers to collaborate with National control programmes to conduct genomics surveillance of malaria to inform malaria control and elimination policies. This study explored genomic researchers' views on engaging with national control programmes to aid malaria elimination efforts in Africa.

Methods: This research employed an exploratory qualitative approach to investigate the views and experiences of malaria genomics researchers across 16 member countries of the Pathogen Genomic Diversity Network Africa (PDNA). In-depth interviews were conducted with each PDNA Principal Investigator, which were recorded, and transcribed verbatim. Subsequently, the data were analysed thematically with NVivo 12 qualitative data analysis software.

Results: The study revealed that majority of malaria genomics researchers focused on understanding the genetic composition and adaptation of the malaria parasite, its vector, and human host. Their investigations delved into areas such as drug and insecticide resistance, parasite evolution, host interactions, human host susceptibility to malaria, diversity of vaccine candidates, and molecular surveillance of malaria. Challenges included limited funding, lack of interest and capacity among National Malaria Control Programmes (NMCP) to use research evidence effectively, and difficulties in communicating data implications to policymakers due to the absence of WHO-certified use cases. Despite these obstacles, researchers expressed a keen interest in forming partnerships with NMCPs to integrate genetic data into malaria control efforts in Africa. They also stressed the importance of enhancing researchers' ability to communicate findings to policymakers and local communities through policy briefs and innovative communication strategies.

Conclusion: The study underscores the need to strengthen partnerships between genomic researchers and NMCPs to support malaria elimination in Africa. Furthermore, researchers should create practical frameworks for easy integration into WHO reporting formats to facilitate the use of molecular and genomic data in malaria control programme decision-making.

Background: In malaria vaccine clinical trials, immune responses after vaccination may be compromised due to immunosuppression caused by concurrent Plasmodium falciparum infection. This has a direct effect on the protective efficacy of the vaccine being evaluated. Therefore, parasite clearance prior to vaccination is being considered. Drugs with good safety and efficacy profiles and a short posttreatment prophylaxis period should be used. Two antimalarial drugs, artesunate (AS) as monotherapy and dihydroartemisinin-piperaquine (DHAPQ), have been evaluated in order to identify the most suitable option for use in future trials.

Methods: A cohort of children aged 1.5-12 years living in the Banfora Health District area was recruited. They were randomly assigned to receive supervised curative doses of AS monotherapy for 7 days or DHAPQ for 3 days. A polymerase chain reaction (PCR) was performed 21 days after treatment to confirm clearance of infection, and only those with a negative PCR were included in the study cohort for a 6-month longitudinal follow-up. Cohort children were actively visited fortnightly to collect blood samples for P. falciparum detection via microscopy and PCR. Passive surveillance was also conducted at the local health facility to record incident malaria episodes that occurred between two active visits.

Results: A total of 513 children were treated. Among these patients, 458 (89.3%) were free of P. falciparum malaria infection on day 21: 87.3% (226/259) in the AS group vs 91.3% (232/254) in the DHAPQ group (p = 0.053). The mean time to first malaria infection by microscopy was 154.9 (2.9) days in the DHAPQ arm and 129.0 (3.9) days in the AS arm (p < 0.01). The incidence rates of clinical malaria episodes during the follow-up period were 0.507 (0.369-0.645) and 0.293 (0.190-0.397) in the AS and DHAPQ arms, respectively (p < 0.05).

Conclusions: These findings suggest that although both drugs are effective in clearing P. falciparum infections, AS is likely to cause no more than minimal interference with the evaluation of vaccine efficacy endpoints and could, therefore, be considered for use.

Trial registration: NCT04601714.