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Objectives To achieve malaria elimination by 2030, the Lao People’s Democratic Republic (PDR) adopted a reactive surveillance and response (RASR) strategy of malaria case notification within 1 day, case investigation and classification within 3 days and foci investigation and response within 7 days. It is important to evaluate the performance and feasibility of RASR implementation in Lao PDR so that the strategy may be optimised and better contribute towards the goal of malaria elimination.Design A mixed-methods study comprising of secondary data analysis of routinely collected malaria surveillance data, quantitative surveys and qualitative consultations was conducted in 2022.Setting Primary data collections for quantitative surveys and qualitative consultations were conducted in Huaphan, Khammouane, Luangprabang and Savannakhet Provinces of Lao PDR.Participants Quantitative surveys were conducted among malaria programme stakeholders and service providers. Qualitative interviews were conducted with malaria programme stakeholders, and focus group discussions with malaria programme stakeholders, service providers and mobile and migrant populations (MMPs).Outcome measures Outcomes of interests were awareness and acceptability of current RASR activities by different group of participants, implementation, performance and feasibility of RASR activities including enablers and barriers.Results In Lao PDR, malaria programme stakeholders and service providers were aware of RASR; however, these activities were not well known in MMPs. Respectively, the timeliness of case notification and case investigation was 0.0% and 15.6% in 2018 but increased to 98.0% and 98.6% in 2022. Implementation of RASR was acceptable to the malaria programme stakeholders and service providers, and continued implementation was perceived as feasible. Nevertheless, issues such as low level of community awareness, high level of migration and limitations in health system capacity were identified.Conclusion Overall, the timeliness of case notification and investigation in Lao PDR was high, and malaria programme stakeholders and service providers had positive opinions on RASR. However, some operational and health system-related barriers were identified, which need to be addressed to improve the performance of RASR in Lao PDR.

Abstract Background To enhance malaria elimination, Vietnam adopted a Reactive Surveillance and Response (RASR) Strategy in which malaria case notification and investigation must be completed within 2 days followed by a focus investigation within 7 days. The nationwide performance of Vietnam’s RASR strategy has yet to be evaluated. This study aims to evaluate the performance and feasibility of RASR in Vietnam, thereby providing recommendations for improved RASR. Methods To assess malaria RASR in Vietnam, a mixed-methods study of (1) secondary data analysis of nationwide malaria case-based dataset from 2017 to 2021; (2) a quantitative survey, and (3) qualitative in-depth interviews and focus group discussions administered to central, provincial and district level stakeholders/staff and to the commune and community level front line health services providers was conducted. Results In Vietnam, there are guidelines and procedures for implementation of each step of RASR. The completeness of case notification on the reported monthly aggregated data was very high in both the paper-based (12,463/12,498, 99.7% in 2017–2020) and electronic reporting systems (467/467, 100% in 2021 when electronic reporting was introduced); however, there were delays in notification while using the paper-based system (timely notification—7,978/12,498, 63.8%). In 2021, the completeness (453/467, 97.0%) and timeliness (371/467, 79.4%) of case investigation were found to be high. Reactive case detection was the major focus investigation response, with fever screening achievement of 88.6% (11,481 / 12,965) and 88.5% (11,471 / 12,965) among index case and neighbouring household members, respectively. Conclusions Overall, there was policy commitment for implementation of RASR in Vietnam. The completeness and timeliness of case notification and case investigation were high and improved after the introduction of the electronic reporting system. More evidence is required for reactive case detection in defining the screening area or population.

Abstract Background Despite recent reductions in Vietnam, malaria transmission persists in some areas in forests and farmlands where a high density of Anopheles mosquitoes relative to other environments occurs. To inform effective malaria control measures, it is important to understand vector bionomics and the malaria transmission role of Anopheles spp. in the highland regions of Vietnam. This study was conducted to quantify the abundance, composition and biting behaviour of the Anopheles mosquito population, and the proportion of Plasmodium spp. infected mosquitoes collected from forest and agricultural farm sites in Gia Lai province, Vietnam. Methods Forest and agricultural farm sites in Gia Lai province were selected for mosquito collections (total eight sites). Mosquito collection was performed by Human-baited Double Net Trap (HDNT), animal-baited traps (ABT) using cattle, and CDC light traps. Captured mosquitoes were identified morphologically, and salivary glands of Anopheles mosquitoes were examined for sporozoites using microscopy. Plasmodium infection was determined by Polymerase Chain Reaction (PCR), and identification of blood meal type was determined by PCR and diffuse serum agglutination assay. Results A total of 1815 Anopheles mosquitoes belonging to 19 species were collected by ABT (n = 1169), HDNT (n = 471) and CDC light trap (n = 175). Anopheles abundance and diversity varied by district and environment. Capture by HDNT of Anopheles of vectorial concern was observed between early evening and early morning. Plasmodium vivax infection was determined by PCR in two Anopheles dirus specimens captured by HDNT in forest sites. Blood from a range of hosts could, including human blood, could be detected in species considered primary and secondary vectors An. dirus, and Anopheles aconitus, and Anopheles maculatus, respectively. Conclusions A low number of Anopheles spp. considered primary vectors of concern and very low numbers of Plasmodium spp. infected Anopheles mosquitoes were captured at the end of the rainy season in the Central Highlands of Vietnam. However, capture species of vectorial concern by HDNT throughout the early to late evening demonstrates that use of additional personal protective measures could supplement current preventative measures, such as bed nets to prevent exposure to vectors of concern in this region.

Abstract Myanmar, a country in Greater Mekong Sub-region, aims to eliminate malaria by 2030. To achieve malaria elimination, Myanmar adopted a reactive surveillance and response strategy of malaria case notification within 1 day and case investigation, foci investigation and response activities within 7 days. A literature review was conducted to gain a better understanding of how the reactive surveillance and response strategies are being implemented in Myanmar including enablers and barriers to their implementation. Only two assessments of the completeness and timeliness of reactive surveillance and response strategy in Myanmar have been published to date. The proportion of positive cases notified within one day was 27.9% and the proportion of positive cases investigated within 7 days as recommended by the national guidelines varied from 32.5 to 91.8% under different settings in reported studies. Strong collaboration between the National Malaria Control Programme and implementing partners, and adequate human resource and financial support contributed to a successful and timely implementation of reactive surveillance and response strategy. Documented enablers for successful implementation of reactive surveillance and response strategy included frontline health workers having good knowledge of reactive surveillance and response activities and availability of Basic Health Staff for timely implementation of foci response activities. Barriers for implementation of reactive surveillance and response activities were also identified, including shortage of human resources especially in hard-to-reach settings, limited mobile phone network services and internet coverage leading to delays in timely notification of malaria cases, lengthy and complex case investigation forms and different reporting systems between Basic Health Staff and volunteers.

Abstract Background Countries of the Greater Mekong Sub-region aim to achieve malaria elimination by 2030. In the region, malaria is concentrated in high-risk areas and populations such as forest-going mobile and migrant populations (MMPs). However, routine protective measures such as long-lasting insecticidal nets do not prevent all infectious bites in these high-risk populations. Evidence for the effectiveness of a personal protection package tailored to forest-going MMPs which is acceptable, feasible, and cost-effective for reducing malaria transmission is required to inform the malaria elimination toolkit in the region. Methods A personal protection package consisting of long-lasting insecticidal hammock net, insect repellent and health communication pamphlet was developed in consultation with relevant implementing partners from Cambodia and Lao PDR. An open stepped-wedge cluster-randomised controlled trial will be conducted over a period of 12 months in a minimum of 488 villages (~ 428 in Lao PDR and ~ 60 in Cambodia) to evaluate the effectiveness of the personal protection package. Villages will be randomised into 11 blocks, with blocks transitioned in random order from control to intervention states at monthly intervals, following a 1-month baseline period. The primary outcome of the trial is the prevalence of Plasmodium spp. infection diagnosed by rapid diagnostic test. Difference in prevalence of malaria infection will be estimated across intervention and control periods using generalized linear mixed modelling. Nested within the stepped-wedge cluster-randomised controlled trial is a mixed-methods study to explore the acceptability of the personal protection package, feasibility of implementing a personal protection package as a vector control intervention, and knowledge, attitude and practice of MMPs regarding malaria prevention; and cost-analysis to determine the cost-effectiveness of implementing a personal protection package. Discussion This study, using a rigorous design and mixed-methods methodology, will evaluate whether a personal protection package can reduce residual malaria transmission among forest-going MMPs in Cambodia and Lao PDR. It will also measure implementation research outcomes such as effectiveness of the intervention package, cost-effectiveness, acceptability, and feasibility, in order to inform potential national and regional policy. Trial registration This trial was prospectively registered on ClinicalTrials.gov (NCT05117567) on 11th November 2021

Abstract Background Strengthening surveillance systems to collect near-real-time case-based data plays a fundamental role in achieving malaria elimination in the Greater Mekong Subregion (GMS). With the advanced and widespread use of digital technology, mHealth is increasingly taking a prominent role in malaria surveillance systems in GMS countries, including Myanmar. In Myanmar’s malaria elimination program, an mHealth system called Malaria Case-based Reporting (MCBR) has been applied for case-based reporting of malaria data by integrated community malaria volunteers (ICMVs). However, the sustainability of such mHealth systems in the context of existing malaria elimination programs in Myanmar is unknown. Methods Focus group discussions were conducted with ICMVs and semi-structured in-depth interviews were conducted with malaria program stakeholders from Myanmar’s Ministry of Health and Sports and its malaria program implementing partners. Thematic (deductive followed by inductive) analysis was undertaken using a qualitative descriptive approach. Results Technological and financial constraints such as inadequate internet access, software errors, and insufficient financial resources to support mobile phone-related costs have hampered users’ access to MCBR. Poor system integrity, unpredictable reporting outcomes, inadequate human resources for system management, and inefficient user support undermined the perceived quality of the system and user satisfaction, and hence its sustainability. Furthermore, multiple parallel systems with functions overlapping those of MCBR were in use. Conclusions Despite its effectiveness and efficiency in malaria surveillance, the sustainability of nationwide implementation of MCBR is uncertain. To make it sustainable, stakeholders should deploy a dedicated human workforce with the necessary technical and technological capacities; secure sustainable, long-term funding for implementation of MCBR; find an alternative cost-effective plan for ensuring sustainable system access by ICMVs, such as using volunteer-owned mobile phones for reporting rather than supporting new mobile phones to them; and find a solution to the burden of multiple parallel systems. Trial registration Not applicable.

Abstract Background In the Greater Mekong Subregion (GMS), current malaria surveillance strategies rely on a network of village health volunteers (VHVs) reporting the results of rapid diagnostic tests (RDTs), known to miss many asymptomatic infections. Integration of more sensitive diagnostic molecular and serological measures into the VHV network may improve surveillance of residual malaria transmission in hard-to-reach areas in the region and inform targeted interventions and elimination responses. However, data on residual malaria transmission that would be captured by these measures in the VHV-led testing and treatment surveillance network in the GMS is unknown. Methods A total of 114 VHVs were trained to collect dried blood spots from villagers undergoing routine RDTs as part of VHV-led active and passive case detection from April 2015 to June 2016. Samples were subjected to molecular testing (quantitative polymerase chain reaction [qPCR]) to determine Plasmodium falciparum and P. vivax infection and serological testing (against P. falciparum and P. vivax antigens) to determine exposure to P. falciparum and P. vivax. Results Over 15 months, 114 VHVs performed 32,194 RDTs and collected samples for molecular (n = 13,157) and serological (n = 14,128) testing. The prevalence of molecular-detectable P. falciparum and P. vivax infection was 3.2% compared to the 0.16% prevalence of Plasmodium spp. by RDT, highlighting the large burden of infections undetected by standard surveillance. Peaks in anti-P. falciparum, but not P. vivax, merozoite IgG seroprevalence coincided with seasonal P. falciparum transmission peaks, even in those with no molecularly detectable parasites. At the individual level, antibody seropositivity was associated with reduced odds of contemporaneous P. falciparum (OR for PfCSP 0.51 [95%CI 0.35, 0.76], p = 0.001, PfAMA1 0.70 [95%CI 0.52, 0.93], p = 0.01, and PfMSP2 0.81 [95%CI 0.61, 1.08], p = 0.15), but not P. vivax infection (OR PvAMA1 1.02 [95%CI 0.73, 1.43], p = 0.89) indicating a potential role of immunity in protection against molecular-detectable P. falciparum parasitaemia. Conclusions We demonstrated that integration and implementation of sample collection for molecular and serological surveillance into networks of VHV servicing hard-to-reach populations in the GMS is feasible, can capture significant levels of ongoing undetected seasonal malaria transmission and has the potential to supplement current routine RDT testing. Improving malaria surveillance by advancing the integration of molecular and serological techniques, through centralised testing approaches or novel point-of-contact tests, will advance progress, and tracking, towards malaria elimination goals in the GMS.

Abstract Background To achieve malaria elimination in the Greater Mekong Subregion, including Myanmar, it is necessary to ensure all malaria cases are detected, treated, and reported in a timely manner. Mobile phone-based applications for malaria reporting, case management, and surveillance implemented at a community-level may overcome reporting limitations associated with current paper-based reporting (PBR), but their effectiveness in this context is unknown. Methods A mixed methods evaluation study was undertaken to determine the effectiveness of a national Malaria Case-Based Reporting (MCBR) mobile phone application in improving malaria case reporting compared to the existing PBR reporting system in Myanmar. Methods included secondary analysis of malaria case report data, questionnaires, focus group discussions and field observations of community volunteers, interviews and direct observations of malaria programme stakeholders, and cost analysis. Using a combination of these approaches the following areas were investigated: data quality and completeness, data access and usage, capacity for timely reporting, the acceptability, functionality, and ease of use of the application and facilitators and barriers to its use, and the relative cost of MCBR compared to the PBR system. Results Compared to PBR, MCBR enabled more accurate and complete data to be reported in a much timelier manner, with 63% of MCBR users reporting they transmit rapid diagnostic test outcomes within 24 h, compared to 0% of PBR users. MCBR was favoured by integrated community malaria volunteers and their supervisors because of its efficiency. However, several technical and operational challenges associated with internet coverage, data transmission, and e-literacy were identified and stakeholders reported not being confident to rely solely on MCBR data for programmatic decision-making. Conclusions Implementation of MCBR provided timely and accurate data for malaria surveillance. Findings from this evaluation study will enable the optimization of an application-based reporting system for malaria monitoring and surveillance in the Greater Mekong Subregion and advance systems to track progress towards, and certify, the achievement of malaria elimination targets.

Abstract Background In parallel with the change of malaria policy from control to elimination and declines in the malaria burden in Greater Mekong Sub-region, the motivation and social role of malaria volunteers has declined. To address this public health problem, in Myanmar, the role and responsibilities of malaria volunteers have been transformed into integrated community malaria volunteers (ICMV), that includes the integration of activities for five additional diseases (dengue, lymphatic filariasis, tuberculosis, HIV/AIDS and leprosy) into their current activities. However, this transformation was not evidence-based and did not consider inputs of different stakeholders. Therefore, qualitative stakeholder consultations were performed to optimize future malaria volunteer models in Myanmar. Methods Semi-structured interviews were conducted with key health stakeholders from the Myanmar Ministry of Health and Sports (MoHS) and malaria implementing partners to obtain their perspectives on community-delivered malaria models. A qualitative descriptive approach was used to explore the experiences of the stakeholders in policymaking and programme implementation. Interview topic guides were used during the interviews and inductive thematic data analysis was performed. Results While ICMVs successfully provided malaria services in the community, the stakeholders considered the ICMV model as not optimal and suggested that many aspects needed to be improved including better training, supervision, support, and basic health staff’s recognition for ICMVs. Stakeholders believe that the upgraded ICMV model could contribute significantly to achieving malaria elimination and universal health care in Myanmar. Discussion and conclusion In the context of high community demand for non-malaria treatment services from volunteers, the integrated volunteer service package must be developed carefully in order to make it effective in malaria elimination programme and to contribute in Myanmar’s pathway to universal health coverage (UHC), but without harming the community. An evidenced-based, community-delivered and preferred model, that is also accepted by the MoHS, is yet to be developed to effectively contribute to achieving malaria elimination and UHC goals in Myanmar by 2030.

Abstract Background Malaria volunteers have contributed significantly to malaria control achieving a reduction of annual parasite incidence to pre-elimination levels in several townships across Myanmar. However, the volunteers’ role is changing as Myanmar transitions from a malaria control to elimination programme and towards the goal of universal health coverage. The aim of the study is to explore the perspectives of community leaders, members and malaria volunteers in South-East Myanmar on community-delivered models to inform an optimal design that targets malaria elimination in the context of primary health care in Myanmar. Methods Qualitative methods including focus group discussions (FGDs) with community members and current or ex-malaria volunteers, and participatory workshops with community leaders were conducted. All data collection tools were pilot tested with similar participants. The FGDs were stratified into male and female participants in consideration of diverse gender roles among the ethnic groups of Myanmar. Data saturation was the key cut-off point to cease recruitment of participants. Inductive thematic analysis was used. Results Community members were willing to be tested for malaria because they were concerned about the consequences of malaria although they were aware that malaria prevalence is low in their villages. Malaria volunteers were the main service providers for malaria and other infectious diseases in the community. Apart from malaria, the community identified common health problems such as the flu (fever, sneezing and coughing), diarrhoea, skin infections and tuberculosis as priority diseases in this order. Incorporating preventive, and whenever possible curative, services for those diseases into the current malaria volunteer model was recommended. Discussion and conclusion There was a gap between the communities’ expectations of health services and the health services currently being delivered by volunteers in the community that highlights the need for reassessment and reform of the volunteer model in the changing context. An evidence-based, community preferred, pragmatic community-delivered integrated model should be constructed based on the context of malaria elimination and progressing towards universal health coverage in Myanmar.

In the Lao People’s Democratic Republic (Lao PDR), village health volunteers play an important role in providing health services including those to reduce the burden of malaria. Over the last two decades, the volunteer network has expanded to bring malaria services closer to communities and contributed to the reduction of malaria cases. However, as malaria test positivity rates decreased, many volunteers have lost motivation to continue providing routine malaria services, and other services they provide may not reflect growing healthcare demands for common diseases in the community. This study explored the perspectives, knowledge and inputs of key health stakeholders and community members in southern Lao PDR on community-delivered models in order to refine the volunteer model in the context of Lao PDR’s primary health care sector and malaria elimination goals. Semi-structured interviews with multi-level health stakeholders, participatory workshops with community leaders, and focus group discussions with community members and current village health volunteers were conducted. Deductive followed by inductive thematic analysis was used to explore and categorise stakeholders’ perspectives on community-delivered models for malaria elimination. Both stakeholders and community members agreed that village health volunteers are essential providers of malaria services in rural communities. Apart from malaria, community members identified dengue, diarrhoea, influenza, skin infections and tuberculosis as priorities (in descending order of importance) and requested community-based primary health care for these diseases. Stakeholders and community members suggested integrating prevention, diagnosis, and treatment services for the five priority diseases into the current malaria volunteer model. A divergence was identified between community members’ expectations of health services and the services currently provided by village health volunteers. Stakeholders proposed an integrated model of healthcare to meet the needs of the community and help to maintain volunteers’ motivation and the long-term sustainability of the role. An evidence-based, integrated community-delivered model of healthcare should be developed to balance the needs of both community members and stakeholders, with consideration of available resources and current health policies in Lao PDR.

Introduction In the Greater Mekong Subregion, community health workers, known as malaria volunteers, have played a key role in reducing malaria in the control phase, providing essential malaria services in areas with limited formal healthcare. However, the motivation and social role of malaria volunteers, and testing rates, have declined with decreasing malaria burden and reorientation of malaria programmes from control to elimination. Provision of additional interventions for common health concerns could help sustain the effectiveness of volunteers and maintain malaria testing rates required for malaria elimination accreditation by the WHO.Methods and analysis The Community-delivered Integrated Malaria Elimination (CIME) volunteer model, integrating interventions for malaria, dengue, tuberculosis, childhood diarrhoea and malaria Rapid Diagnostic Test (RDT)-negative fever, was developed based on global evidence and extensive stakeholder consultations. An open stepped-wedge cluster-randomised controlled trial, randomised at the volunteer level, will be conducted over 6 months to evaluate the effectiveness of the CIME model in Myanmar. One hundred and forty Integrated Community Malaria Volunteers (ICMVs, current model of care) providing malaria services in 140 villages will be retrained as CIME volunteers (intervention). These 140 ICMVs/villages will be grouped into 10 blocks of 14 villages, with blocks transitioned from control (ICMV) to intervention states (CIME), fortnightly, in random order, following a 1-week training and transition period. The primary outcome of the trial is blood examination rate determined by the number of malaria RDTs performed weekly. Difference in rates will be estimated across village intervention and control states using a generalised linear mixed modelling analytical approach with maximum likelihood estimation.Ethics and dissemination The study was approved by Institutional Review Board, Myanmar Department of Medical Research (Ethics/DMR/2020/111) and Alfred Hospital Ethics Review Committee, Australia (241/20). Findings will be disseminated in peer-review journals, conferences and regional, national and local stakeholder meetings.Trial registration number NCT04695886

Abstract Background Community-delivered models have been widely used to reduce the burden of malaria. This review aimed to explore different community-delivered models and their relative effectiveness in terms of coverage and malaria-metric outcomes in order to inform the design and implementation of Community Health Worker (CHW) programmes for malaria control and elimination. Methods A systematic review of studies investigating the impact of community-delivered models on coverage and malaria-metric (parasitaemia and hyperparasitaemia, malaria case and mortality, anaemia, and fever) outcomes compared to non- community-delivered models was undertaken by searching in five databases of published papers and grey literature databases. Data were extracted from studies meeting inclusion and quality criteria (assessed using relevant tools for the study design) by two independent authors. Meta-analyses were performed where there was sufficient homogeneity in effect and stratified by community-delivered models to assess the impact of each model on coverage and malaria-metric outcomes. Results 28 studies were included from 7042 records identified. The majority of studies (25/28) were performed in high transmission settings in Africa and there was heterogeneity in the type of, and interventions delivered as part of the community-delivered models. Compared to non- community-delivered models, community-delivered models increased coverage of actual bed net usage (Relative Risk (RR) = 1.64 95% CI 1.39, 1.95), intermittent preventive treatment in pregnancy (RR = 1.36 95% CI 1.29, 1.44) and appropriate and timely treatment of febrile children, and improved malaria-metric outcomes such as malaria mortality (RR = 0.58 95% CI 0.52, 0.65). However, the considerable heterogeneity was found in the impact of community-delivered models in reducing, parasitaemia and hyperparasitaemia prevalence, anaemia incidence, fever prevalence and malaria caseload. Statistical comparisons of different community-delivered models were not undertaken due to the heterogeneity of the included studies in terms of method and interventions provided. Conclusion Overall, the community-delivered model is effective in improving the coverage of malaria interventions and reducing malaria-associated mortality. The heterogeneity of the community-delivered models and their impact on malaria-metric indices suggests that evidence for context-specific solutions is required. In particular, community-delivered models for malaria elimination, integrated with services for other common primary health problems, are yet to be evaluated.

Abstract Background To combat emerging drug resistance in the Greater Mekong Sub-region (GMS) the World Health Organization and GMS countries have committed to eliminating malaria in the region by 2030. The overall approach includes providing universal access to diagnosis and treatment of malaria, and sustainable preventive measures, including vector control. Topical repellents are an intervention that can be used to target residual malaria transmission not covered by long lasting insecticide nets and indoor residual spraying. Although there is strong evidence that topical repellents protect against mosquito bites, evidence is not well established for the effectiveness of repellents distributed as part of malaria control activities in protecting against episodes of malaria. A common approach to deliver malaria services is to assign Village Health Volunteers (VHVs) to villages, particularly where limited or no services exist. The proposed trial aims to provide evidence for the effectiveness of repellent distributed through VHVs in reducing malaria. Methods The study is an open stepped-wedge cluster-randomised controlled trial randomised at the village level. Using this approach, repellent (N,N-diethyl-benzamide – 12% w/w, cream) is distributed by VHVs in villages sequentially throughout the malaria transmission season. Villages will be grouped into blocks, with blocks transitioned monthly from control (no repellent) to intervention states (to receive repellent) across 14 monthly intervals in random order). This follows a 4-week baseline period where all villages do not receive repellent. The primary endpoint is defined as the number of individuals positive for Plasmodium falciparum and Plasmodium vivax infections diagnosed by a rapid diagnostic test. Secondary endpoints include symptomatic malaria, Polymerase Chain Reaction (PCR)-detectable Plasmodium spp. infections, molecular markers of drug resistance and antibodies specific for Plasmodium spp. parasites. Discussion This study has been approved by relevant institutional ethics committees in Myanmar and Australia. Results will be disseminated through workshops, conferences and peer-reviewed publications. Findings will contribute to a better understanding of the optimal distribution mechanisms of repellent, context specific effectiveness and inform policy makers and implementers of malaria elimination programs in the GMS. Trial registration Australian and New Zealand Clinical Trials Registry (ACTRN12616001434482). Retrospectively registered 14th October 2016.

BackgroundThe World Health Organization has yet to endorse deployment of topical repellents for malaria prevention as part of public health campaigns. We aimed to quantify the effectiveness of repellent distributed by the village health volunteer (VHV) network in the Greater Mekong Subregion (GMS) in reducing malaria in order to advance regional malaria elimination.Methods and findingsBetween April 2015 and June 2016, a 15-month stepped-wedge cluster randomised trial was conducted in 116 villages in Myanmar (stepped monthly in blocks) to test the effectiveness of 12% N,N-diethylbenzamide w/w cream distributed by VHVs, on Plasmodium spp. infection. The median age of participants was 18 years, approximately half were female, and the majority were either village residents (46%) or forest dwellers (40%). No adverse events were reported during the study. Generalised linear mixed modelling estimated the effect of repellent on infection detected by rapid diagnostic test (RDT) (primary outcome) and polymerase chain reaction (PCR) (secondary outcome). Overall Plasmodium infection detected by RDT was low (0.16%; 50/32,194), but infection detected by PCR was higher (3%; 419/13,157). There was no significant protection against RDT-detectable infection (adjusted odds ratio [AOR] = 0.25, 95% CI 0.004-15.2, p = 0.512). In Plasmodium-species-specific analyses, repellent protected against PCR-detectable P. falciparum (adjusted relative risk ratio [ARRR] = 0.67, 95% CI 0.47-0.95, p = 0.026), but not P. vivax infection (ARRR = 1.41, 95% CI 0.80-2.47, p = 0.233). Repellent effects were similar when delayed effects were modelled, across risk groups, and regardless of village-level and temporal heterogeneity in malaria prevalence. The incremental cost-effectiveness ratio was US$256 per PCR-detectable infection averted. Study limitations were a lower than expected Plasmodium spp. infection rate and potential geographic dilution of the intervention.ConclusionsIn this study, we observed apparent protection against new infections associated with the large-scale distribution of repellent by VHVs. Incorporation of repellent into national strategies, particularly in areas where bed nets are less effective, may contribute to the interruption of malaria transmission. Further studies are warranted across different transmission settings and populations, from the GMS and beyond, to inform WHO public health policy on the deployment of topical repellents for malaria prevention.Trial registrationAustralian and New Zealand Clinical Trials Registry (ACTRN12616001434482).

The World Health Organization identifies a strong surveillance system for malaria and its mosquito vector as an essential pillar of the malaria elimination agenda. Anopheles salivary antibodies are emerging biomarkers of exposure to mosquito bites that potentially overcome sensitivity and logistical constraints of traditional entomological surveys. Using samples collected by a village health volunteer network in 104 villages in Southeast Myanmar during routine surveillance, the present study employs a Bayesian geostatistical modeling framework, incorporating climatic and environmental variables together with Anopheles salivary antigen serology, to generate spatially continuous predictive maps of Anopheles biting exposure. Our maps quantify fine-scale spatial and temporal heterogeneity in Anopheles salivary antibody seroprevalence (ranging from 9 to 99%) that serves as a proxy of exposure to Anopheles bites and advances current static maps of only Anopheles occurrence. We also developed an innovative framework to perform surveillance of malaria transmission. By incorporating antibodies against the vector and the transmissible form of malaria (sporozoite) in a joint Bayesian geostatistical model, we predict several foci of ongoing transmission. In our study, we demonstrate that antibodies specific for Anopheles salivary and sporozoite antigens are a logistically feasible metric with which to quantify and characterize heterogeneity in exposure to vector bites and malaria transmission. These approaches could readily be scaled up into existing village health volunteer surveillance networks to identify foci of residual malaria transmission, which could be targeted with supplementary interventions to accelerate progress toward elimination. [ABSTRACT FROM AUTHOR]

Objectives: To achieve malaria elimination by 2030, the Lao People's Democratic Republic (PDR) adopted a reactive surveillance and response (RASR) strategy of malaria case notification within 1 day, case investigation and classification within 3 days and foci investigation and response within 7 days. It is important to evaluate the performance and feasibility of RASR implementation in Lao PDR so that the strategy may be optimised and better contribute towards the goal of malaria elimination., Design: A mixed-methods study comprising of secondary data analysis of routinely collected malaria surveillance data, quantitative surveys and qualitative consultations was conducted in 2022., Setting: Primary data collections for quantitative surveys and qualitative consultations were conducted in Huaphan, Khammouane, Luangprabang and Savannakhet Provinces of Lao PDR., Participants: Quantitative surveys were conducted among malaria programme stakeholders and service providers. Qualitative interviews were conducted with malaria programme stakeholders, and focus group discussions with malaria programme stakeholders, service providers and mobile and migrant populations (MMPs)., Outcome Measures: Outcomes of interests were awareness and acceptability of current RASR activities by different group of participants, implementation, performance and feasibility of RASR activities including enablers and barriers., Results: In Lao PDR, malaria programme stakeholders and service providers were aware of RASR; however, these activities were not well known in MMPs. Respectively, the timeliness of case notification and case investigation was 0.0% and 15.6% in 2018 but increased to 98.0% and 98.6% in 2022. Implementation of RASR was acceptable to the malaria programme stakeholders and service providers, and continued implementation was perceived as feasible. Nevertheless, issues such as low level of community awareness, high level of migration and limitations in health system capacity were identified., Conclusion: Overall, the timeliness of case notification and investigation in Lao PDR was high, and malaria programme stakeholders and service providers had positive opinions on RASR. However, some operational and health system-related barriers were identified, which need to be addressed to improve the performance of RASR in Lao PDR., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)