CDC light traps underestimate the protective efficacy of an indoor spatial repellent against bites from wild Anopheles arabiensis mosquitoes in Tanzania

BACKGROUND: Methods for evaluating efficacy of core malaria interventions in experimental and operational settings are well established but gaps exist for spatial repellents (SR). The objective of this study was to compare three different techniques: (1) collection of blood-fed mosquitoes (feeding), (2) human landing catch (HLC), and (3) CDC light trap (CDC-LT) collections for measuring the indoor protective efficacy (PE) of the volatile pyrethroid SR product Mosquito Shield() METHODS: The PE of Mosquito Shield() against a wild population of pyrethroid-resistant Anopheles arabiensis mosquitoes was determined via feeding, HLC, or CDC-LT using four simultaneous 3 by 3 Latin squares (LS) run using 12 experimental huts in Tanzania. On any given night each technique was assigned to two huts with control and two huts with treatment. The LS were run twice over 18 nights to give a sample size of 72 replicates for each technique. Data were analysed by negative binomial regression. RESULTS: The PE of Mosquito Shield() measured as feeding inhibition was 84% (95% confidence interval (CI) 58-94% [Incidence Rate Ratio (IRR) 0.16 (0.06-0.42), p < 0.001]; landing inhibition 77% [64-86%, (IRR 0.23 (0.14-0.36) p < 0.001]; and reduction in numbers collected by CDC-LT 30% (0-56%) [IRR 0.70 (0.44-1.0) p = 0.160]. Analysis of the agreement of the PE measured by each technique relative to HLC indicated no statistical difference in PE measured by feeding inhibition and landing inhibition [IRR 0.73 (0.25-2.12) p = 0.568], but a significant difference in PE measured by CDC-LT and landing inhibition [IRR 3.13 (1.57-6.26) p = 0.001]. CONCLUSION: HLC gave a similar estimate of PE of Mosquito Shield() against An. arabiensis mosquitoes when compared to measuring blood-feeding directly, while CDC-LT underestimated PE relative to the other techniques. The results of this study indicate that CDC-LT could not effectively estimate PE of the indoor spatial repellent in this setting. It is critical to first evaluate the use of CDC-LT (and other tools) in local settings prior to their use in entomological studies when evaluating the impact of indoor SR to ensure that they reflect the true PE of the intervention

Mixed method evaluation of a learning from excellence programme for community health workers in Neno, Malawi

Background: Community Health Workers (CHWs) play an essential role in linking communities to facility-based healthcare. However, CHW programmes have often been hampered by low levels of staff motivation, and new tools aimed at improving staff motivation and work environment are needed. One such intervention is the “Learning from Excellence” (LfE) programme. We aimed to assess feasibility, outputs, and impact of a co-designed LfE programme on CHW motivation, in Neno District. Methods: We conducted a convergent mixed-method evaluation of the LfE programme. Co-design of the programme and forms took place between October 2019 and January 2020. LfE forms submitted between September and November 2020 were analysed using descriptive statistics and memos summarising answers to the open-ended question. To investigate experiences with LfE we conducted in-depth semi-structured interviews with key stakeholders, CHWs, and site supervisors, which were analysed thematically. A pre-post intervention questionnaire was developed to assess the impact of the co-designed LfE intervention on CHW motivation and perceived supervision. Outcomes were triangulated into a logic model. Results: In total 555 LfE forms were submitted, with 34.4% of CHWs in Neno District submitting at least one LfE report. Four themes were identified in the interviews: LfE implementation processes, experience, consequences, and recommendations. A total of 50 CHWs participated in the questionnaire in January 2020 and 46 of them completed the questionnaire in December 2020. No statistically significant differences were identified between pre-and post-LfE measurements for both motivation (Site F: p = 0.86; Site G: p = 0.31) and perceived supervision (Site F: p = 0.95; Site G: p = 0.45). A logic model, explaining how the LfE programme could impact CHWs was developed. Conclusions: Many CHWs participated in the LfE intervention between September 2020 and November 2020. LfE was welcomed by CHWs and stakeholders as it allowed them to appreciate excellent work in absence of other opportunities to do so. However, no statistically significant differences in CHW motivation and perceived supervision were identified. While the intervention was feasible in Neno District, we identified several barriers and facilitators for implementation. We developed a logic model to explain contextual factors, and mechanisms that could lead to LfE outcomes for CHWs in Neno District. The developed logic model can be used by those designing and implementing interventions like LfE for health workers

A household-based community health worker programme for non-communicable disease, malnutrition, tuberculosis, HIV and maternal health: a stepped-wedge cluster randomised controlled trial in Neno District, Malawi

BACKGROUND: Community health worker (CHW) programmes are a valuable component of primary care in resource-poor settings. The evidence supporting their effectiveness generally shows improvements in disease-specific outcomes relative to the absence of a CHW programme. In this study, we evaluated expanding an existing HIV and tuberculosis (TB) disease-specific CHW programme into a polyvalent, household-based model that subsequently included non-communicable diseases (NCDs), malnutrition and TB screening, as well as family planning and antenatal care (ANC). METHODS: We conducted a stepped-wedge cluster randomised controlled trial in Neno District, Malawi. Six clusters of approximately 20 000 residents were formed from the catchment areas of 11 healthcare facilities. The intervention roll-out was staggered every 3 months over 18 months, with CHWs receiving a 5-day foundational training for their new tasks and assigned 20-40 households for monthly (or more frequent) visits. FINDINGS: The intervention resulted in a decrease of approximately 20% in the rate of patients defaulting from chronic NCD care each month (-0.8 percentage points (pp) (95% credible interval: -2.5 to 0.5)) while maintaining the already low default rates for HIV patients (0.0 pp, 95% CI: -0.6 to 0.5). First trimester ANC attendance increased by approximately 30% (6.5pp (-0.3, 15.8)) and paediatric malnutrition case finding declined by 10% (-0.6 per 1000 (95% CI -2.5 to 0.8)). There were no changes in TB programme outcomes, potentially due to data challenges. INTERPRETATION: CHW programmes can be successfully expanded to more comprehensively address health needs in a population, although programmes should be carefully tailored to CHW and health system capacity

Increasing utilisation of perinatal services: estimating the impact of community health worker program in Neno, Malawi

Abstract Background By 2015, Malawi had not achieved Millennium Development Goal 4, reducing maternal mortality by about 35% from 675 to 439 deaths per 100,000 livebirths. Hypothesised reasons included low uptake of antenatal care (ANC), intrapartum care, and postnatal care. Involving community health workers (CHWs) in identification of pregnant women and linking them to perinatal services is a key strategy to reinforce uptake of perinatal care in Neno, Malawi. We evaluated changes in uptake after deployment of CHWs between March 2014 and June 2016. Methods A CHW intervention was implemented in Neno District, Malawi in a designated catchment area of about 3100 women of childbearing age. The pre-intervention period was March 2014 to February 2015, and the post-intervention period was March 2015 to June 2016. A 5-day maternal health training package was delivered to 211 paid and supervised CHWs. CHWs were deployed to identify pregnant women and escort them to perinatal care visits. A synthetic control method, in which a “counterfactual site” was created from six available control facilities in Neno District, was used to evaluate the intervention. Outcomes of interest included uptake of first-time ANC, ANC within the first trimester, four or more ANC visits, intrapartum care, and postnatal care follow-up. Results Women enrolled in ANC increased by 18% (95% Credible Interval (CrI): 8, 29%) from an average of 83 to 98 per month, the proportion of pregnant women starting ANC in the first trimester increased by 200% (95% CrI: 162, 234%) from 10 to 29% per month, the proportion of women completing four or more ANC visits increased by 37% (95% CrI: 31, 43%) from 28 to 39%, and monthly utilisation of intrapartum care increased by 20% (95% CrI: 13, 28%) from 85 to 102 women per month. There was little evidence that the CHW intervention changed utilisation of postnatal care (− 37, 95% CrI: − 224, 170%). Conclusions In a rural district in Malawi, uptake of ANC and intrapartum care increased considerably following an intervention using CHWs to identify pregnant women and link them to care

Structural diversity and tree density drives variation in the biodiversity-ecosystem function relationship of woodlands and savannas

Positive biodiversity-ecosystem function relationships (BEFRs) have been widely documented, but it is unclear if BEFRs should be expected in disturbance-driven systems. Disturbance may limit competition and niche differentiation, which are frequently posited to underlie BEFRs. We provide the first exploration of the relationship between tree species diversity and biomass, one measure of ecosystem function, across southern African woodlands and savannas, an ecological system rife with disturbance from fire, herbivores and humans. We used >1000 vegetation plots distributed across 10 southern African countries, and structural equation modelling, to determine the relationship between tree species diversity and aboveground woody biomass, accounting for interacting effects of resource availability, disturbance by fire, tree stem density and vegetation type. We found positive effects of tree species diversity on aboveground biomass, operating via increased structural diversity. The observed BEFR was highly dependent on organismal density, with a minimum threshold of c. 180 mature stems ha-1. We found that water availability mainly affects biomass indirectly, via increasing species diversity. The study underlines the close association between tree diversity, ecosystem structure, environment and function in highly disturbed savannas and woodlands. We suggest that tree diversity is an under-appreciated determinant of wooded ecosystem structure and function

Precipitation gradients drive high tree species turnover in the woodlands of eastern and southern Africa

Savannas cover one-fifth of the Earth's surface, harbour substantial biodiversity, and provide a broad range of ecosystem services to hundreds of millions of people. The community composition of trees in tropical moist forests varies with climate, but whether the same processes structure communities in disturbance-driven savannas remains relatively unknown. We investigate how biodiversity is structured over large environmental and disturbance gradients in woodlands of eastern and southern Africa. We use tree inventory data from the Socio-Ecological Observatory for Studying African Woodlands (SEOSAW) network, covering 755 ha in a total of 6780 plots across nine countries of eastern and southern Africa, to investigate how alpha, beta, and phylogenetic diversity varies across environmental and disturbance gradients. We find strong climate-richness patterns, with precipitation playing a primary role in determining patterns of tree richness and high turnover across these savannas. Savannas with greater rainfall contain more tree species, suggesting that low water availability places distributional limits on species, creating the observed climate-richness patterns. Both fire and herbivory have minimal effects on tree diversity, despite their role in determining savanna distribution and structure. High turnover of tree species, genera, and families is similar to turnover in seasonally dry tropical forests of the Americas, suggesting this is a feature of semiarid tree floras. The greater richness and phylogenetic diversity of wetter plots shows that broad-scale ecological patterns apply to disturbance-driven savanna systems. High taxonomic turnover suggests that savannas from across the regional rainfall gradient should be protected if we are to maximise the conservation of unique tree communities

Precipitation gradients drive high tree species turnover in the woodlands of eastern and southern Africa

Savannas cover one-fifth of the Earth's surface, harbour substantial biodiversity, and provide a broad range of ecosystem services to hundreds of millions of people. The community composition of trees in tropical moist forests varies with climate, but whether the same processes structure communities in disturbance-driven savannas remains relatively unknown. We investigate how biodiversity is structured over large environmental and disturbance gradients in woodlands of eastern and southern Africa. We use tree inventory data from the Socio-Ecological Observatory for Studying African Woodlands (SEOSAW) network, covering 755 ha in a total of 6780 plots across nine countries of eastern and southern Africa, to investigate how alpha, beta, and phylogenetic diversity varies across environmental and disturbance gradients. We find strong climate-richness patterns, with precipitation playing a primary role in determining patterns of tree richness and high turnover across these savannas. Savannas with greater rainfall contain more tree species, suggesting that low water availability places distributional limits on species, creating the observed climate-richness patterns. Both fire and herbivory have minimal effects on tree diversity, despite their role in determining savanna distribution and structure. High turnover of tree species, genera, and families is similar to turnover in seasonally dry tropical forests of the Americas, suggesting this is a feature of semiarid tree floras. The greater richness and phylogenetic diversity of wetter plots shows that broad-scale ecological patterns apply to disturbance-driven savanna systems. High taxonomic turnover suggests that savannas from across the regional rainfall gradient should be protected if we are to maximise the conservation of unique tree communities

Precipitation gradients drive high tree species turnover in the woodlands of eastern and southern Africa

DATA AVAILABILITY STATEMENT : Data are available from the Dryad Digital Repository: https://DOI.org/10.5061/dryad.k98sf7mcb (Davies et al. 2023).Savannas cover one-fifth of the Earth’s surface, harbour substantial biodiversity, and provide a broad range of ecosystem services to hundreds of millions of people. The community composition of trees in tropical moist forests varies with climate, but whether the same processes structure communities in disturbance-driven savannas remains relatively unknown. We investigate how biodiversity is structured over large environmental and disturbance gradients in woodlands of eastern and southern Africa. We use tree inventory data from the Socio-Ecological Observatory for Studying African Woodlands (SEOSAW) network, covering 755 ha in a total of 6780 plots across nine countries of eastern and southern Africa, to investigate how alpha, beta, and phylogenetic diversity varies across environmental and disturbance gradients. We find strong climate-richness patterns, with precipitation playing a primary role in determining patterns of tree richness and high turnover across these savannas. Savannas with greater rainfall contain more tree species, suggesting that low water availability places distributional limits on species, creating the observed climate-richness patterns. Both fire and herbivory have minimal effects on tree diversity, despite their role in determining savanna distribution and structure. High turnover of tree species, genera, and families is similar to turnover in seasonally dry tropical forests of the Americas, suggesting this is a feature of semiarid tree floras. The greater richness and phylogenetic diversity of wetter plots shows that broad-scale ecological patterns apply to disturbance-driven savanna systems. High taxonomic turnover suggests that savannas from across the regional rainfall gradient should be protected if we are to maximise the conservation of unique tree communities.The UK Natural Environment Research Council.http://www.ecography.orgam2024Plant Production and Soil ScienceSDG-15:Life on lan