Background. Long-lasting insecticidal nets (LLINs) are commonly distributed through mass distribution campaigns (MDCs). MDCs are commonly followed by substantial loss of LLINs, affecting coverage. Here, data from an MDC and a malaria indicator survey (MIS) on Bioko Island were used to characterize LLIN mobility. Methods. Between October 2014 and July 2015, an MDC reached most of the households of the island. Distributed nets were marked with a unique code corresponding to the community where they were distributed. An MIS conducted in August and September 2015 allowed to measure LLIN loss and mobility by verifying the number of existing nets and their community code. Multivariate models identified factors associated with LLINs with mismatched codes. A source-sink analysis measuring risk gradient between the source community and the sink household was used to assess the overall effect of migrating nets. Results. The MIS revealed that 40.4% of LLINs distributed during the MDC had been lost. Among the surviving nets (7,393/12,397), community codes were visible only for 3,413 (46.2%), and 551 (16.1%) revealed a mismatched code. The factor most strongly associated with mismatched LLINs was open eaves (OR: 1.88; 95% CI: 1.48 – 2.38, p < 0.001). The source sink analysis showed that while the majority of LLINs migrated from lower to higher risk areas (62.3%), almost a third migrated in the opposite direction. Conclusion. While redistribution had a positive impact on some communities by serving populations at higher risk of transmission, many households in high-risk areas lost their nets to areas with lower risk. This, coupled with the significant LLIN loss post-MDC, pointed to critical inefficiencies and prompted a shift in LLIN distribution strategy from MDC to demand-driven fixed distribution points.

Context Rapeseed has become a key global oilseed crop, valued for oil, biofuel, and its role in diversifying cereal-based systems in regions such as South Europe, North Africa, Australia, and beyond. Seed yield (SY) is determined by seed number (SN) and seed weight (SW), but their relative importance remains less clear than in cereals, where grain number predominates. Unlike cereals, rapeseed’s reproductive morphology, indeterminate growth, and higher energetic cost of lipid-rich seeds suggest greater plasticity of SW, potentially making it as influential as SN in yield determination. Evidence from high-yielding environments shows SW can compensate for SN reductions, though results vary across conditions. We hypothesized that SW would display greater plasticity in rapeseed than observed in cereals and would therefore contribute as much as SN to determining SY. To rigorously test this hypothesis, we compiled and analyzed a broad, unbiased dataset from published experiments conducted across Asia, Australia, Northern Europe, North America, and South America to assess the role of SW in explaining SY variation in rapeseed. This approach allowed us to (i) disentangle the relative contributions of SN and SW, (ii) quantify their degree of compensation under contrasting conditions, and (iii) assess whether SW plasticity indeed plays a more decisive role in rapeseed yield determination than in cereals. Methods We conducted a comprehensive meta-analysis integrating experimental data across diverse environments, genotypes, and management conditions. To generate a large and unbiased database, we compiled data of SY, SN and SW from crop-based experiments reported in figures and tables in three rigorous and prestigious international journals: Crop Science, European Journal of Agronomy, and Field Crops Research. The same search criteria were used across all three journals to recall all papers related to rapeseed yield components: (canola OR rapeseed OR “rape seed” OR “oilseed rape” OR “Brassica napus”) AND (yield OR grain OR seed OR kernel), targeting the title, abstract, and keywords. The search was carried out between March and April 2025. A total of 427 papers were initially retrieved. After excluding controlled-conditions experiments and/or approaches using isolated plants, we ended up with a database including 4308 observations from 74 peer-reviewed studies. Results Across the database, SN overwhelmingly explained SY variation in rapeseed, while SW showed very low plasticity and contributed little to overall SY. Large environmental and genotypic effects on SY were consistently explained by changes in SN, with trade-offs between SN and SW only becoming apparent under small yield variations. This indicates that SN is the primary, highly plastic determinant of SY, while SW plays only a minor role except under narrow yield ranges. Conclusions Contrary to the initial hypothesis, rapeseed showed the same yield pattern as wheat and barley: SN is the sole component that accounts for substantial yield variations, while SW remains conservative. This supports a broader evolutionary principle whereby species without maternal care optimize fitness through offspring number rather than size, making SN highly plastic but with low heritability, and SW stable but with high heritability. Under environmental variation, changes in SN were mainly driven by silique number (NSi), while under genotypic variation both NSi and seeds per silique (SPSi) contributed similarly. Greater variability in NSi under environmental drivers explains its stronger association with SN compared to genotypic drivers. Implications From an applied perspective, these findings highlight the importance of management practices aimed at sustaining source capacity for the critical period to increase SN. Furthermore, breeding for genotypes that combine high SW stability with uncompromised SN offers a viable pathway to improve yield across environments.

Objective:To estimate routine immunization coverage, compare coverage estimates derived from vaccination cards and caregiver recall, and investigate factors associated with incomplete immunization among children aged 18 months to 6 years in communities with a high malaria prevalence in the Malabo district of Equatorial Guinea. Methods:A cross-sectional survey was nested within a larger study and was conducted between September 2019 and March 2020. Children aged 18 months to 6 years living in 13 malaria-endemic communities in Malabo District, Bioko Island were enrolled. Immunization status was ascertained from vaccination cards or caregiver recall. Results:Of the 297 children, with verified immunization status, 86 (29%) were fully immunized according to the national schedule. Coverage estimates were similar whether verified by vaccination card (28%, 34/121) or caregiver recall (30%, 52/176). Children aged 18 months and 2 years had higher completion rates than children aged 2-6 years: 45% (39/86) versus 22% (47/211), aOR = 0.42, 95% CI [0.20, 0.87]). The other factors examined (sex, ethnicity andcommunity area) were not significantly associated with immunization status. Conclusion:Overall immunization coverage in this population was low. Younger children had higher completion rates, possibly reflecting improved program performance in recent years or differential recall bias. Further community based studies, in both urban and peri-urban areas needed to identify reasons for gaps in vaccination coverage and to inform targeted interventions.

Long-lasting insecticidal nets (LLINs) are commonly distributed through mass distribution campaigns (MDCs). MDCs are often followed by substantial loss of LLINs, affecting coverage. Here, data from an MDC and a malaria indicator survey (MIS) on Bioko Island were used to characterize LLIN mobility. Between October 2014 and July 2015, an MDC reached most of the households of the island. All nets distributed were marked with a unique code corresponding to the community where they were distributed. An MIS conducted in August and September 2015 allowed to measure LLIN loss and mobility by verifying the number of existing nets and the community code. Multivariate models were used to identify factors associated with households with LLINs with mismatched codes. A source-sink analysis measuring risk gradient between the source community and the sink household was used to assess the overall effect of migrating nets. The MIS revealed that of the 11,599 LLINs distributed to surveyed households, 7274 (62.7

Over the last 20 years, malaria transmission on Bioko Island, Equatorial Guinea has declined dramatically thanks to the implementation of robust malaria control activities, centered around island-wide indoor residual spraying (IRS). In 2024 Bioko Island experienced a lapse in malaria control funding, and as a result vector control activities (including IRS) were interrupted. However, agreements with funders allowed for both a previously planned malaria indicator survey (MIS) and the subsequent implementation of indoor residual spraying (IRS) in late 2024. This study analyses routine case data from public health facilities from 2019-2024 and annual cross-sectional MIS data from 2019- 2024 using interrupted time series methods to quantify the impact of the interruption and reestablishment of control activities on Bioko Island. In 2024, the number of confirmed cases reported was 41% higher than the 2021-2023 average, and the Plasmodium falciparum prevalence rate ( Pf PR) rose by three percentage points. Statistical modeling estimated that 25.3% (95% CI 12.0-36.3%) of 2024 cases were avertable if control activities had been maintained, and that the interruption was associated with an increased Pf PR in 2024, above previous trends (adjusted OR 1.16, 95% CI 1.05-1.29). Moreover, the reintroduction in IRS in late 2024 was found to have averted an estimated additional 7.0% (95% CI 3.0-10.2%) increase in confirmed cases. In just one year with interruptions to control, malaria transmission and burden quickly resurged on Bioko Island. However, Bioko’s experience demonstrates that the reestablishment of control activities can equally rapidly contain, and reverse resurgence associated with control interruptions.

BACKGROUND:Effective malaria control requires accurate identification of Plasmodium infections to tailor interventions appropriately. Rapid diagnostic tests (RDTs) are crucial tools for this purpose due to their small size and ease-of-use functionality. These tests typically target the Plasmodium falciparum histidine-rich protein 2 (HRP2) antigen. However, some strains of P. falciparum have deletions in the hrp2 and hrp3 genes, which may result in a false negative diagnosis using HRP2-based RDTs. Additionally, RDTs have a detection limit of 100 parasites per microlitre, insufficient for identifying low-density infections that sustain malaria transmission. This study explores integrating molecular monitoring using a novel cartridge-based PCR test, PlasmoPod, using samples from a malaria indicator survey (MIS) on Bioko Island, Equatorial Guinea to enhance detection of low-density infections and inform targeted malaria control strategies. METHODS:The study utilized a combination of RDTs and the DiaxxoPCR device for molecular monitoring. The device DiaxxoPCR uses a prefilled cartridge system, termed PlasmoPod for a malaria-based assay that employs a qPCR assay targeting 18S rDNA/rRNA. Samples from the 2023 MIS were extracted from dried blood spots (DBS), qPCR run in duplicate on the PlasmoPod. Epidemiological data from the MIS were merged with molecular data and the association between MIS variables to malaria infection by qPCR, and low-density infections were measured. RESULTS:The integration of molecular monitoring revealed a proportion of low-density infections that circumvented RDTs diagnosis. Notably, individuals in urban communities and those reporting recent fever were more likely to harbour low-density, asymptomatic malaria infections. Findings suggest that urban residents, although less associated to malaria infection than rural residents by both RDT and qPCR, may be serving as a transmission reservoir. The relationship between low-density infections and individuals who recently reported fever may reflect recent anti-malarial treatment or natural clearance, and thus have lingering parasites in their blood. CONCLUSION:The study highlights the limitations of HRP2-based RDTs in detecting low density infections and underscores the potential of molecular tools like PlasmoPod in malaria surveillance. By identifying elusive transmission reservoirs and tracking parasite importation, molecular monitoring can play a crucial role in achieving malaria elimination. The findings advocate for the broader implementation of molecular diagnostics in malaria programs, especially in areas with low transmission, to enhance the detection and targeting of hidden reservoirs of infection.

A malaria control program established in 2004 on Bioko Island, Equatorial Guinea, achieved significant reductions in malaria prevalence; however, progress subsequently stalled, leading to a proposal to develop and implement a highly effective malaria vaccine to increase impact. After conducting clinical trials of Sanaria® (Rockville, MD) Plasmodium falciparum ( P. falciparum ) sporozite vaccines against P. falciparum malaria, which demonstrated safety and efficacy, a larger phase 3 trial was planned to support vaccine licensure for specific target populations and eventual island-wide malaria elimination. The Equatorial Guinea Pilot Study for Recruitment, Screening and Participant Registry (EGRESPAR) assessed the health status of the target population and generated a registry of eligible children and adults. Households in areas with malaria prevalence ≥15% were randomly selected, aiming to register 2,100 healthy Equatoguineans divided equally into age groups of 1.5–9, 10–17, and 18–50 years. A total of 6,493 individuals from 1,807 households, who considered themselves or their children to be healthy, completed questionnaires; 2,021 were screened using phase 3 enrollment criteria, 643 were excluded, and 1,378 were entered into the registry. Among those screened, 13.6% had Plasmodium , 1.8% had Loa loa , 4.8% had hepatitis B, 0.5% had hepatitis C, and 2.1% had HIV. Adults were twice as likely to have clinically relevant medical conditions, such as obesity, hypertension, or diabetes, meeting exclusion criteria compared to children. In conclusion, there was a significant prevalence of infections and chronic medical conditions among Bioko Island residents who considered themselves or their children to be healthy and interested in clinical research participation, particularly in adults. The EGRESPAR successfully generated a registry to support the initiation of a large-scale phase 3 vaccine trial.

Recent decades have highlighted the impact of climate change on field crops around the globe, with drought and extreme heat as the main drivers. However, a consistent and continuous increase in night temperature has been documented over time, but with very little attention and research on its impact on the yield of major field crops. This opinion paper presents the current state of the art on this topic, highlights the lack of research, identifies some potential causes, and draws attention to the need for future investment to fill the knowledge gap on this topic. Securing future productivity gains for major field crops will depend on more targeted crop improvement and agronomic management to enhance crop resilience to multiple stresses, including night temperature as a relevant stress that is usually overlooked (out of sight, out of mind!).

Context: Global food demand is projected to rise, making it essential to enhance agricultural production to ensure food security while minimizing environmental impacts, particularly in the face of climate change challenges. Understanding the determination of grain yield (GY) in barley is crucial for future advancements in this crop. Objective: This study examines the relationships between the two major components of GY (grain number-GN and grain weight-GW), when driven by genetic and environmental factors. Methods: We compiled data of GY and its numerical components (i.e. GN and GW) to generate a large and unbiased database from every single paper having the word "barley" in the title published over 25 years in four prestigious international journals: Field Crop Research, European Journal of Agronomy, Crop Science and Crop and Pasture Science (formerly Australian Journal of Agricultural Research) between January 1996 and December 2021, both inclusive. Results: GN was significantly better correlated with GY than GW, accounting for 86 % of the variation in GY compared to just 13 % for GW. The changes in GY responsiveness to environmental and genetic factors were mainly due to variations in GN, especially in scenarios with high responsiveness. In contrast, low-responsiveness cases showed trade-offs between GN and GW, suggesting compensatory mechanisms that may not accurately reflect competition for resources. Conclusions: The potential to increase barley GY relies heavily on GN, emphasizing the need to optimise conditions during the critical period of GN determination. Implications: Barley crops under typical field conditions are generally not limited by resource availability during grain filling.

BACKGROUND: Pregnant women are particularly vulnerable to many health conditions, including infectious diseases, which place them at elevated risk of severe outcomes. In particular, malaria poses a significant burden during pregnancy, and as such there has long been a strong focus on delivering malaria prevention interventions to pregnant women during antenatal care (ANC), including long-lasting insecticide-treated nets (LLINs) and intermittent preventive treatment in pregnancy (IPTp). However, outreach to drive uptake of these interventions presents some distinct challenges. For example, pregnant women may not attend ANC or may not do it in public health facilities, where these interventions are freely available, precluding access. In this study, an implementation of routine annual indoor residual spraying (IRS) on Bioko Island, Equatorial Guinea was leveraged to identify pregnant women and conduct follow-up visits focused on awareness and uptake of LLINs and IPTp. METHODS: IRS campaign data was used to generate lists of households with pregnant women for follow-up visits, during which communication agents conducted an interview based on relevant sections of a malaria indicator survey to assess knowledge about malaria, LLINs and IPTp, and uptake of these interventions. Uptake was defined on an ordinal, three-category scale, and ordinal regression modeling was performed to assess the relationship between uptake and knowledge indicators. RESULTS: In total, 1,567 households were visited, and 589 pregnant women identified. There was a high awareness about LLINs (76.9% cited LLINs as a malaria prevention method), but low awareness of IPTp (34.5% could cite any benefit and 37.1% were aware of availability in public health facilities). In line with awareness levels, regular use of LLINs (54.8% reported using every night) was higher than IPTp uptake (35.2% on track for three doses). Ordinal regression modelling confirmed that LLIN use on some or all nights was associated with awareness that LLINs prevent malaria, and IPTp uptake was associated with awareness of the number of doses required. CONCLUSIONS: This work demonstrated that complementary malaria control interventions can be leveraged to identify pregnant women for further outreach. The information collected provides a baseline to evaluate the impact of future activities on Bioko Island and suggests that increasing awareness of IPTp could improve coverage, while further increasing LLIN use will likely require identifying specific barriers to use.

Objective:To test 50% indoor residual spraying coverage (percentage of households sprayed) for non-inferiority against the recommended 80% coverage for malaria control. Methods:Indoor residual spraying was done in 2021 and 2022 on Bioko, Equatorial Guinea, in a control arm (80% coverage) and intervention arm (50% coverage) with 37 clusters each. We assessed malaria infection in a representative sample of the population during annual surveys using rapid diagnostic tests. We compared the change in the odds of Plasmodium falciparum infection between baseline and post-intervention using difference-in-differences analysis within a survey-weighted binomial generalized linear model. Given differences between the arms at baseline, we adjusted the model for indoor residual spraying coverage at baseline. Findings:Relative to baseline, the odds of malaria infection post-intervention were 1.11 (95% confidence interval, CI: 0.81-1.52) in the 80% arm and 0.97 (95% CI: 0.72-1.29) in the 50% arm. In the adjusted model, the change in the odds of P. falciparum infection was no greater in the intervention arm than in the control arm (odds ratio: 0.89; 95% CI: 0.58-1.36), with the upper CI being lower than the non-inferiority margin of 1.43. Conclusion:There was no evidence that 50% coverage was inferior in preventing malaria, which supports the use of this target in settings where this level makes indoor residual spraying feasible by increasing the cost-effectiveness and equity of the intervention.

Mosquito dispersal plays an important role in mosquito ecology and mosquito-borne pathogen transmission. While reaction-diffusion and patch-based models with simple flux assumptions for emigration have played a predominant role in modeling mosquito dispersal, mosquito behavioral ecology - in particular, the process of searching for resources - is usually ignored by diffusion-based models. We thus set out to analyze mosquito movement using highly mimetic models, to see what we could learn from a different approach. Here, we explore mosquito dispersal in behavioral state microsimulation models, in which mosquitoes are in behavioral states and search for the required resources that are distributed on a landscape. Models of this sort are laborious and challenging to work with, so we developed ramp.micro, an R package to build, solve, analyze, and visualize behavioral state microsimulation models for mosquitoes. We show that even when resources are distributed randomly and uniformly, mosquito populations tend to form highly spatially structured communities. We also show that some heterogeneity in mosquito population densities is attributed to features of a network defined by searching and the spatial distribution of resources. These models highlight the importance of understanding mosquito behaviors and resource availability as factors structuring mosquito population movement. Motivated by these dynamics, spatial models for mosquito ecology and mosquito-borne pathogen transmission would benefit from considering resource availability as a factor affecting mosquito movement and dispersal.

Indoor residual spraying (IRS) is one of the core vector control interventions available to malaria control programs. Normative and scientific guidance has long held that very high IRS coverage (at least 80 to 85% houses sprayed) is necessary to provide community protection, but there is little evidence backing these recommendations, in large part due to the operational and ethical concerns that conducting appropriate trials of differing IRS coverage levels would raise. The present study leverages data from four years of targeted IRS implementation on Bioko Island, Equatorial Guinea, to estimate a dose–response curve of IRS coverage. Due to the observational nature of the data, a double robust causal inference technique was utilized. The results suggest that at all spatial scales examined a threshold providing community protection was reached at much lower coverage levels than previously assumed (30 to 50%). Sensitivity analysis corroborated this result across multiple methods, but there was less agreement on whether extremely high coverage ( ≥ 85%) has additional benefit. A secondary analysis of the impact of changing operational coverage targets found that significantly reducing coverage targets (to 30 to 60%) could provide nearly the same protection as maintaining the existing 80% target in Bioko. While these findings are limited in strength by the observational nature of the data and may be specific to the context of Bioko Island, they raise important questions for further research on how IRS coverage impacts epidemiological outcomes and on how malaria control programs should set programmatic IRS coverage targets.

The Bioko Island Malaria Elimination Project (BIMEP) has made significant progress in reducing the prevalence of Plasmodium falciparum on Bioko Island, Equatorial Guinea. However, like other malaria endemic islands like São Tomé and Principe and Zanzibar, Tanzania, elimination efforts are hampered by imported infections. In an effort to understand the local transmission dynamics and the influence of importation on Bioko Island's P. falciparum population, whole-genome sequences were generated from field samples collected during the BIMEP's 2019 Malaria Indicator Survey (MIS). Within the sub-Saharan African context, we observed Bioko Island parasites did not significantly differentiate from nearby continental neighbors. Among Bioko infections, within-host diversity and the quantity of polyclonal infections appear similar to an area of moderate malaria transmission. However, we observed higher than expected genetic diversity among Bioko parasites, similar to high transmission areas, suggesting imported strains are contributing to transmission on the island. Among Bioko's closest geographical neighbors, the flow of parasites with Bioko appeared more pronounced with the Gabonese parasite population, implying more importation may be coming from this region than others. Overall, despite significant investment in malaria control, results illustrate the challenges of eliminating malaria without both interrupting local transmission and accounting for importation from higher transmission areas, likely due to human migration. For there to be sustained progress towards elimination, the BIMEP needs, if feasible, to conduct targeted interventions of outgoing/incoming travelers, expand malaria control interventions to the continental region of Equatorial Guinea, and ideally conduct cross-border interventions in collaboration with the malaria control program in Gabon.