Search strategy

Temporal and linguistic scope

We restricted the study to publications dated from 2000 to 2024. This timeframe was selected to ensure robust data availability and comparability, as publications prior to 2000 were significantly less likely to be digitized and indexed in the databases utilized, which would have introduced substantial selection bias into our analysis.

We limited articles screening to readily available English and Spanish due to the authors fluency in these languages and in recognition of the ethical challenges of appropriately reporting on articles in other languages without personnel expertise to do so. This decision enabled direct engagement with source materials without relying on translation, thereby reducing the risk of misinterpretation or misrepresentation of findings from the included literature.

Search execution and article management

We collected identified articles in Zotero and conducted blind screening using Rayyan.ai software.

Screening process

We employed an iterative two-stage screening process:

Stage 1: Title, Keyword, and Abstract Review: We reviewed titles, keywords, and abstracts to determine potential article inclusion based on alignment with study objectives. If there were any disagreements between two of the reviewers a third reviewer would be consulted.

Stage 2: Full-text Review: We conducted a comprehensive review of the full text of each article retained from Stage 1 and extracted population, intervention, comparison, and outcome to generate a literature matrix and further assess its fit with the study objectives and confirm final inclusion. Fig 1 is the PRISMA flowchart which represents the flow of extraction.

Primary search strategy

The following PubMed search served as the primary search strategy (Table 1). We adjusted for each additional database to match their respective language conventions and keyword requirements:

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Table 1. Search strategy.

https://doi.org/10.1371/journal.pntd.0014621.t001

Primary prevention

Primary prevention involves actions taken to protect people who are at risk but not yet affected by a disease. The main goal is to stop the disease from developing in the first place, focusing on individuals who are currently healthy. This approach often includes strategies to reduce exposure to potential hazards or to strengthen the body’s defenses, thereby stopping the onset of illness before any symptoms appear [28]. In the context of vector-borne diseases, this includes community education, environmental management, and measures to prevent mosquito breeding and bites. For example, using insecticide-treated bed nets to prevent mosquito bites is a primary prevention strategy against malaria. By sleeping under these nets, individuals avoid contact with mosquitoes that may carry the malaria parasite, thereby reducing their risk of ever contracting the disease. Two studies [15 and 27] focused on interventions such as mosquito control, education, and community mobilization, often led by community health workers (CHWs).

Arnbrister [15] conducted a comprehensive study in the United States (southern Arizona) examining CHWs’ capacity for Aedes aegypti mosquito larval surveillance and disease education. The intervention included intensive training on mosquito biology, disease transmission, and surveillance techniques. While pre-and post-training assessments demonstrated significant improvements in CHW knowledge about mosquito-borne diseases and prevention strategies, the study revealed important implementation challenges. During the initial mosquito season, CHWs successfully collected larval samples and conducted community education activities. However, logistical barriers—such as inability to take the time required when conducting home visits, billing code for service, and competing responsibilities from other health programs substantially reduced their participation in the following season, highlighting the critical importance of sustained organizational support and manageable workload distribution. Building on similar integrated approaches, [27] implemented a multi-component intervention in Guatemala that combined CHW training with innovative mosquito monitoring tools (ovitraps) and structured community engagement activities. The results were promising: 88% of participating CHWs achieved accreditation for improved vector control competency, ecological monitoring showed increased mosquito egg capture compared to standard methods, and community participation in mosquito control activities expanded significantly. [27] demonstrated that when CHWs receive appropriate tools and training, they can effectively bridge the gap between technical mosquito control measures and community behavior change.

The following studies explored more participatory approaches to primary prevention. [21] examined the work of “Health Animators” in rural Malawi, who conducted 2,704 malaria prevention workshops across vulnerable communities. The intervention resulted in measurable behavior changes, increased uptake of preventive treatments, and broader community participation in malaria control activities. Notably, the success of these workshops was significantly influenced by the involvement of respected village leaders, illustrating how social and cultural dynamics can either facilitate or hinder health behavior change initiatives.

In Thailand, Therawiwat et al. [24] employed an action research methodology that emphasized community empowerment through participatory training and ongoing stakeholder engagement.

The intervention led to improvements in knowledge about dengue prevention, increased perceived susceptibility to the disease, and enhanced community participation in larval survey activities. Most importantly, entomological indices dropped significantly in intervention areas, providing concrete evidence of the intervention’s impact on vector populations. The study’s emphasis on continuous community empowerment and regular stakeholder meetings emerged as key factors in sustaining behavior change over time.

The Cuban studies by [26] provide compelling evidence for the effectiveness of structured community partnerships in primary prevention. The initial 2007 study evaluated the creation of neighborhood-level Community Working Groups that brought together diverse stakeholders in dengue prevention efforts. The way in which these groups operated were very closely aligned to community health workers. These groups successfully reduced household risk behaviors, improved environmental risk management, and positively impacted entomological indicators. The participatory model proved particularly effective at resolving community concerns while simultaneously addressing public health objectives.

The 2011 follow-up study provided crucial evidence of long-term impact during a dengue outbreak in Santiago de Cuba. Areas where Community Working Groups had been implementing interventions showed significantly lower dengue attack rates compared to control areas. This demonstrated that well-structured community participation can provide sustained protection against vector borne disease transmission even during epidemic conditions.

Two Brazilian studies highlighted important challenges in integrating vector control activities with existing CHW responsibilities. Cazola et al. (2014) [17] compared two cities with different approaches to incorporating dengue control into Community Health Agents’ duties. While dengue control indicators were maintained in both settings, the city where CHAs managed both dengue control and broader health responsibilities experienced declines in other health services, raising critical questions about optimal workload distribution and task prioritization. Similarly,Pereira et al. (2021) [22] evaluated the integration of Endemic Disease Control Workers into Brazil’s Family Health Strategy. Although the integration improved teamwork and enhanced dengue control activities, participants identified significant legal and coordination barriers that limited their effectiveness. These findings underscore that successful integration requires careful attention to role definitions, legal frameworks, and coordination mechanisms to preserve both disease-specific outcomes and broader public health goals.

Across all primary prevention studies, several key themes emerge. CHW-led interventions show the greatest success when supported by consistent training, adequate logistical resources, and integration with formal health systems. Community engagement and leadership support are essential facilitators; while competing responsibilities and inadequate organizational support represent significant barriers. The evidence suggests that primary prevention interventions require sustained investment and careful attention to implementation context to achieve and maintain their intended impacts.

Secondary prevention

Secondary prevention focuses on identifying diseases at an early stage, specifically in people who do not yet show symptoms but may already have underlying changes in their bodies [28]. These individuals appear healthy, but tests can detect the disease before symptoms develop. Secondary prevention is commonly carried out through screening programs. For instance, in the context of vector-borne diseases, using rapid diagnostic tests (RDTs) to screen for malaria in communities helps detect infections in people who do not yet feel sick. This allows for early treatment and prevents further spread of the disease. In this scoping review, this typically involves CHWs identifying early symptoms, performing routine testing, and distributing preventive treatment.

Boakye et al. [29] conducted an in-depth qualitative assessment of CHW needs for sustaining community case management of malaria (CCMm) in Kenya. The study revealed that CHWs played central roles in malaria testing using rapid diagnostic tests, treatment distribution, and educational outreach to community members. However, their effectiveness was heavily dependent on reliable access to essential supplies, regular refresher training, appropriate financial compensation, and meaningful integration with formal health systems. The study emphasized that investing in CHW infrastructure—including both material resources and professional development—is essential for maintaining quality secondary prevention services at the community level. Building on similar themes, [16] implemented a community based intermittent preventive treatment in pregnancy (IPTp) program in Burkina Faso. CHWs were trained to identify pregnant women, provide preventive malaria treatment, and link them to antenatal care services. The intervention resulted in improved coverage of preventive treatment and increased access to formal antenatal care. While CHWs generally reported feeling capable of supporting the program, the study reinforced that ongoing training and supportive supervision were critical components. Additionally, the involvement of both male and female CHWs proved beneficial, with female CHWs more effective at engaging pregnant women and male CHWs providing important community credibility and support.

Two studies specifically examined CHW competencies in secondary prevention activities. Habimana et al. (2016; [20]) assessed knowledge, attitudes, and practices regarding malaria among CHWs in Rwanda, finding that most participants demonstrated good understanding of malaria transmission and symptoms. However, significant gaps existed in their prevention and management behaviors, and the study identified important associations between CHW demographics, knowledge levels, and practice quality. These findings highlighted the value of targeted, tailored training interventions that address both knowledge gaps and practice improvement. In Cameroon, [18] surveyed CHWs involved in malaria prevention and control, discovering that while knowledge and attitudes were generally strong, important misconceptions persisted about specific aspects of malaria prevention and management. CHWs appropriately recognized the severity of malaria and supported hospital-based treatment for severe cases, but continued education was needed to correct misunderstandings and reinforce evidence-based practices. The study found that marital status was significantly associated with malaria knowledge, suggesting that personal characteristics and life experiences may influence CHW learning and performance.

The secondary prevention studies collectively demonstrate that CHWs can effectively contribute to early detection and management of vector-borne diseases, but their success depends heavily on systematic support systems. Key requirements include reliable supply chains for diagnostic materials and medications, regular training updates to maintain technical competencies, appropriate supervision and feedback mechanisms, and clear integration pathways with formal health services. The evidence suggests that secondary prevention interventions require more intensive support systems than primary prevention activities due to their technical complexity and the critical importance of accurate diagnosis and treatment decisions.

Tertiary prevention

Tertiary prevention focuses on managing disease after symptoms have appeared, aiming to lessen its severity and prevent complications. Unlike secondary prevention, which tries to stop the disease before it fully develops, tertiary prevention works to minimize the long-term impact once the illness is already present. This often involves rehabilitation and ongoing care to improve quality of life [28]. For example, dengue fever, tertiary prevention might include supportive treatments and physical therapy for patients who develop severe complications such as dengue hemorrhagic fever or prolonged joint pain, helping them recover and reduce lasting disability.

[23] conducted a comparative study of drug distribution strategies for lymphatic filariasis control in Tamil Nadu, India. The research compared community-directed treatment (ComDT), where community members similarly described as community health workers took primary responsibility for medication distribution, with traditional health service-organized treatment (HST), where formal health workers-maintained control over the distribution process. Both approaches achieved similar coverage rates (68% for ComDT versus 74% for HST), indicating that community-based distribution could reach comparable proportions of the target population. However, drug consumption compliance was slightly higher in the health service-led approach (59% versus 53%), suggesting that formal health system involvement may improve treatment adherence.

The study’s findings have important implications for tertiary prevention strategies. While community participation proved vital for achieving broad population coverage, the slightly superior compliance rates in the health service-led approach suggested that a hybrid model combining community engagement with centralized coordination might optimize both reach and treatment effectiveness. The authors concluded that health service-led approaches with strong community engagement components may be more efficient and scalable for large-scale treatment programs, while still maintaining the community trust and participation that are essential for program success.

Synthesis of data

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Fig 1. PRISMA flowchart.

https://doi.org/10.1371/journal.pntd.0014621.g001

Limitations and future research

Of note, the state of the literature on community health workers’ role in vector borne disease control is not yet sufficient to evaluate their overall role or effects across studies and contexts. Thus, we conducted a scoping review, to assess the state of the evidence, and clarify barriers and facilitators to their use in prevention and control programs. While scoping reviews are valuable for mapping the existing literature and identifying research gaps, they have inherent limitations. One notable limitation is the potential for selection bias in including studies that were solely academic research and published within specified databases. However, we tried to mitigate this through software use (e.g., multiple search engines) and other methods recommended [26]. Nonetheless, the review process may inadvertently omit relevant research due to restrictive search criteria or exclude non-English and non-Spanish language studies. Additionally, variability in study quality and methodological rigor across included articles can impact the reliability and generalizability of the findings and make synthesis across divergent methods and contexts. Scoping reviews tend to be appropriate for literature where a detailed assessment of study outcomes may not be informative, focusing instead on broad trends and themes, which may limit the depth of insights into specific intervention effects.

Future research should prioritize several areas. First, large-scale implementation studies are needed to understand how successful community-based interventions can be scaled up while maintaining effectiveness. Second, more research is needed on tertiary prevention approaches and long-term disease management roles for CHWs. Additionally, exploring intersectoral collaboration between community health workers and community animal health workers using One Health frameworks could strengthen approaches to zoonotic vector-borne disease control. Third, comparative studies examining different models of CHW integration with formal health systems could inform optimal approaches to program design. Finally, economic evaluations of different CHW program models would provide important evidence for resource allocation decisions.