Pilot study

In 2019, a pilot study was designed to test the feasibility of citizen science as a strategy to enhance the reach of Aedes mosquito surveillance (Craig et al. 2021). The study recruited, trained, and equipped 13 general public participants from across Honiara to trap and identify to the genus level (using a magnifying glass and morphological identification key) mosquitoes caught within participants’ household settings, and report count data to health authorities. Biogents Sentinel II traps were used as they are considered among the best performing for collecting Aedes mosquitos (Akaratovic et al. 2017; Degener et al. 2021). Trap locations were geo-located, and data provided by the citizen scientists were mapped to measure the distribution, density, and change in mosquito populations over time, thereby providing new evidence for arboviral risk assessment.

From a scientific perspective, the study was successful with participants engaged and able to identify mosquitoes with a high degree of accuracy (a 94% agreement between participants’ and an entomologist’s assessment) (Craig et al. 2021). From an implementation science viewpoint, we identified both opportunities and challenges. We found that the opportunity to contribute to a project of social benefit, the chance to learn new skills, and the frequency of engagement with project staff were prime motivators for citizen scientists’ participation and continued engagement in the pilot. Conversely, we found that the choice of an overly complex and cumbersome trap that required electricity to operate, lack of buy-in from all household members, insufficient personal finances (to buy electricity and phone credit required to run the trap and report data by short message service), and inconvenience were barriers to sustained participation. An unexpected benefit was a self-reported change in the mosquito bite prevention behaviour of the participants and their advocacy to friends, family, and their community for environmental change to address exposure risks. A detailed account of this pilot study is reported elsewhere (Craig et al. 2021).

Given the pilot study’s success, there was motivation to continue the EMS project, albeit in a refined model considering lessons learned. Although motivation was high, the emergence of COVID-19 and ensuing disruptions stalled progress and no action was taken for the two years following the end of the study.

Implementation of the Solomon Islands citizen science mosquito surveillance project

In early 2022, the partners reconvened to discuss opportunities to re-invigorate the initiative. Subsequently, and with the financial and technical support of the Pacific Mosquito Surveillance Strengthening for Impact (PacMOSSI) program (www.pacmossi.org), the collaboration was extended to include the Ministry of Education and a school-based citizen science Aedes mosquito surveillance and education project was developed.

Project coordination

The EMS project had both health surveillance and health promotion goals (Figure 2).

The coordination group met periodically to conceptualise and design the project, to extend invitations to schools to gain participants, and to monitor and refine the implementation model.

To build sustainability and scalability of the project, responsibility for its implementation was embedded as an assessable component of the Solomon Islands National University (SINU) post-graduate diploma of public health students’ capstone course. The capstone course is undertaken as a one-month field placement towards the end of students’ coursework. It is designed to provide scholars with the opportunity to gain field experience, apply their newfound knowledge, and make them “work ready” upon graduation. The scheme has close ties with the National Vector-Borne Disease Control Program (www.solomons.gov.sb/ministry-of-health-medical-services/) and is used to build the human resource capacity of the program, particularly in rural and remote areas.

At the commencement of their capstone, SINU scholars were oriented to the Solomon Islands EMS project, trained how to engage with and effectively provide educational content to high school–aged children, and supported to make teaching resources (Supplemental File 1). Scholars were assigned a school at which to implement the project. Scholars worked individually or in small groups, depending on where they were placed.

School selection

High schools were used as mosquito surveillance sites. Schools were purposefully and pragmatically selected considering the proximity to SINU scholars’ capstone placement locations, the number of schools within the location, and current (or recent) evidence of arboviral disease transmission within the vicinity.

Schools that were approached were given information about the project and what would be expected. Schools that did not respond (positively or negatively) to the invitation were contacted one more time. If no response was received, no further invitations were sent. Figure 3a shows the location of schools that have been engaged to date (as of July 2023).

School student engagement, training, and trap development

The SINU scholars actively engaged with schools that responded positively to the invitations to participate in the program. The SINU scholars organised a time to visit the school and deliver a ~2-hour workshop to grade-10 students (aged ~16 years). The workshops involved two parts: (i) a short interactive presentation that provided information about mosquitoes, arboviral diseases, arboviral disease transmission risks, public health surveillance methods for arboviral disease vectors, citizen science, and the project; and (ii) a practical component during which high school students built a simple gravid mosquito egg collection trap (ovitraps) out of readily available material (Figure 4). Scholars brought printed materials and, where appropriate, a laptop to aid their presentation.

Ovitraps were constructed by cutting the top off a wide-based (for stability) plastic container (such as a soft drink bottle) that could comfortably hold ~300 ml of water. As female mosquitoes prefer to lay eggs in dark places (Day 2016), clear or light-coloured containers were blackened by placing them in a larger dark container (such as a plant pot), wrapping them with dark paper, or painting them. A strip of red cotton fabric 22 cm long and 3.5 cm wide was placed inside the container so that it hung down the inside to the bottom. The cloth was secured to the container’s rim by a strong paperclip. The cloth strip serves as a medium to which mosquito eggs laid by visiting female mosquitos bind. Traps were filled with ~225 mls of rainwater (collected from a rainwater tank) and a single lucerne chicken food pellet was added. The pellet served as a mosquito-attracting lure. Each trap was labelled with a unique trap identification number (a trap ID). The scholars brought the materials required to make the traps with them when they visited the schools.

Figure 4 provides a photo of the equipment used, and Table 1 an equipment list and alternatives that may be considered.

After construction of the ovitraps, the SINU scholar/s led the high school students on a walk around the school’s campus to identify suitable locations to set up the traps. Suitable locations were those that were outdoors, at low risk of being disturbed, in a shaded place close to the ground and amongst foliage but with a clear line of sight, and within 5 m of a building occupied by humans. Multiple traps were set on each school campus. Traps were placed >30 m apart to reduce inter-trap interference. Each trap’s geolocation was recorded using the Global Positioning System (GPS) function built into modern smart mobiles.

Each trap’s identification code, geo-coordinates, and set date and time was recorded in a purpose-built data collection phone application, as was information about the environment in which the trap was set.

Collecting, packaging, and returning eggs

Five days after setting the traps, the SINU scholar returned to the school and, together with students, harvested eggs laid in the ovitraps. The process of egg harvesting involved the careful removal and part-drying of the red cloth fabric hung inside the trap (the ovistrip), and packaging of the part-dried strip in an airtight zip-lock bag. The associated trap’s ID code was written on the bag. Mosquito eggs that are properly prepared remain viable for a few months, allowing flexibility as to when they are processed and analysed.

The zip-lock bags containing the ovistrips were transported to an insectary at SINU for processing, rearing, and analysis. The time and date the bags were received at the insectary, along with the information provided on the enclosed data forms, were recorded.

Mosquito rearing and identification

At the SINU insectary, the ovistrips were carefully removed from the returning zip-lock bag, placed into a clear container, and flooded with ~200 ml of rainwater. A larval food pellet was added, and a polyethylene netting fixed across the opening to prevent other mosquitoes from laying eggs (ovipositing) in the water. Eggs were hatched and reared to pupae (Figure 5) before being transferred by pipette to a separate container filled with ~200 ml rainwater. The container was covered with a netting barrier to prevent emerged adult mosquitoes from escaping. Using an adult mosquito aspirator, emerged adults were transferred to a killing tube where cotton wool soaked in chloroform was used to terminate the mosquitoes.

Using a dissecting microscope (x4 magnification), reared mosquitoes were identified using standard morphology methods and an adult mosquito identification key (Anish and Sreelakshmi 2013; Rueda 2004) to the species level. Figure 6 shows students processing the specimens.

This rearing and identification process was performed by the SINU scholars under the supervision of a medical entomologist. Data on the date that eggs were flooded, when larvae were transferred, and when emerged adult mosquitoes were terminated was recorded.

Data management

A purpose-built data collection, storage, and visualization tool was developed using Beyond Essential System’s integrated Tupaia software and Meditrack mobile application (https://www.bes.au/products/tupaia/). The customized Meditrack application operates on both Android and iOS-based mobile devices, enabling convenient form-based digital data entry and upload to a cloud-based database. In instances of no or unstable internet connectivity, data entered using the application was stored on the device until a connection could be restored.

The tool allowed the project coordinators to tailor user-specific functionality and data access rights, thereby streamlining the interface and limiting unnecessary access to information. For example, SINU scholars were granted permission to enter data related to the specific schools they worked with, and view data collected from across all schools, while teachers’ access was limited to information relevant to their school. The adaptable data collection system architecture allowed for easy modifications and enhanced flexibility.

The process of data entry into the Meditrack application occurred at multiple stages. First, when setting the trap, the unique ID, geolocation, environmental, and set time data were recorded. Second, on receipt of the zip-lock bag at the insectary, data about collection dates and times were added. Third, as the mosquitoes were reared, key process data were added. And finally, data on mosquitoes, to the species level, were added to the record. Each trap’s unique ID served as the record link throughout this process, connecting all the data fields.

Data analysis

To assess the population presence and estimate the abundance of Aedes mosquitoes, the study employed entomological indices as per the recommendations of the Solomon Islands Ministry of Health and Medical Services. Specifically, the positive ovitrap index (POI), mean eggs per trap (MET), and mean mosquitos per trap by species (MMT_S) were calculated. The POI value provided insights into the distribution of mosquitoes, while the POI, MET and MMT values offered indicators of mosquito population abundance. To gain understanding of Aedes mosquito distribution across communities, a descriptive analysis incorporating temporal and spatial data was conducted. The formula used to calculate the abovementioned indicators are as follows.

Reporting of results

The data resulting from the analysis was utilized to create informative maps, visually depicting the distribution and estimated density of mosquito species (Figure 3b). These maps were shared with the Vector-Borne Disease Control Program of the Solomon Islands Ministry of Health and Medical Services, enhancing arboviral risk assessment efforts. Additionally, the maps were presented to the participating schools, thereby closing the feedback loop with the community stakeholders

By showcasing the scientific significance of systematic data collection and rigorous analysis, these maps served as a valuable tool for fostering community engagement.

Simplicity is key to success

A key lesson from our project was that in resource-limited contexts, the design of a citizen science initiative must prioritize simplicity to ensure stability, scalability, and long-term sustainability while considering the contextual constraints likely to be encountered.

For example, during the initial phase of our project, we utilized a Biogent Sentinel II trap, which offered superior performance but posed challenges when used in household settings by civil society members. Its dependence on electricity for operation and its relatively large size resulted in limited acceptance, with instances of traps being stored away and left unused. Additionally, the trap’s design focused on capturing adult mosquitoes, requiring careful handling and time-consuming specimen retrieval and packaging. The considerable cost of these traps also presented a significant investment for health authorities. In response, we adapted our project by transitioning to a simpler trap—the ovitrap—which can be easily constructed using readily available materials. While ovitraps have their own limitations and challenges, such as the need for time, space, and skilled personnel for rearing and analysis of collected egg samples, they offered a cost-effective and context-appropriate alternative.

Through the pilot study, we realized that placing the burden on the already time-constrained Ministry of Health and Medical Services workforce was unsustainable. Consequently, we decided to leverage established community groups, focusing on engaging classes of school students as citizen scientists. This approach, combined with the adoption of a simpler and cost-effective sampling method (as described above), enabled us to leverage others while also achieving economies of scale for time investments made. Furthermore, we integrated the responsibility for project implementation as a requirement for SINU scholars’ capstone projects, thereby creating opportunities for authentic learning, reducing the workload on Ministry of Health and Medical Service staff, and creating opportunities to expand the initiative to new locations. With roll-out embedded within SINU’s curriculum, we have found implementation to be sustainable without need for additional funding.

Ensuring relevance for end users

During the pilot study, it became evident that citizen participants felt empowered and motivated to take proactive measures to reduce their own and their family’s exposure to Aedes mosquitoes. For instance, observing increased catch numbers, one participant reported organizing clean-ups of vector breeding sites around their homes. Additionally, in one inspiring instance, citizens advocated for behavioural and environmental changes within their community to reduce habitats conducive to mosquito breeding. By framing the citizen science project as a part of school-based learning, and creating opportunities for citizen participation in a practical scientific endeavour directly relevant to their own lives, we hope to extend engagement and behaviour-change outcomes. We expect that the approach will also instil a sense of personal responsibility for health security and, as students engage in the project and learn about arboviral disease transmission and control, they will become agents of change within their families and communities, leading to heightened disease prevention efforts and improved public health outcomes. Further studies to verify any change in participants’ knowledge, attitude, and practice are planned.

Maintaining stakeholder participation

Our initiative demonstrated that by engaging a diverse range of stakeholders, we not only discovered new opportunities but also devised innovative solutions to challenges. Sustaining participation in such projects is an ongoing endeavour that necessitates continuous investment in building and maintaining trusting relationships with all involved parties. Crucially, we recognised the importance of ensuring that each stakeholder derived value from their engagement. For instance, anecdotal accounts suggest that the national health authority benefited from the initiative by acquiring additional data at no extra cost, while schoolteachers found value in incorporating a practical activity into their science curriculum. Furthermore, SINU students report their education was enriched through participation in the project.

Our observations align with the findings of researchers Souza et al. (2019), who emphasised that for citizen science initiatives, investing in stakeholders is paramount to achieving sustainability. They add that actively involving stakeholders in the planning and framing of the initiative holds equal significance to the data collected, ensuring a collaborative and mutually beneficial endeavour.

Financial sustainability

In low-resourced settings, where achievement of health service delivery goals is highly resource-sensitive, any new initiative must add demonstrable benefits to justify the expenditure of resources that could otherwise be allocated to established programs, facilities, equipment, staff, medicines, and other essential commodities (Cullen and Hassall 2017). Although the EMS project is relatively inexpensive to implement, it still incurs costs, and securing continuous funding remains one of the main challenges. Thus far, the project has been supported by grants from the WHO’s “for research on diseases of poverty” program and PacMOSSI. However, these funding sources are time-limited and cannot be relied upon for long-term sustainability.

In this context, it becomes critical to demonstrate the value of the project in terms of its outcomes and impact, as well as its cost-benefit. Proving the efficacy and positive outcomes of the initiative is paramount in garnering support from potential funding sources, both local and international. Moreover, while funding remains uncertain, establishing and leveraging local partnerships for implementation is imperative. An excellent example of this approach can be observed in the Solomon Islands, where the citizen science project has been successfully integrated into the core curriculum of SINU scholars, ensuring a continuous pipeline of engaged participants.

It is important to avoid viewing voluntary participation in science solely to cut costs (Cronemberger et al. 2023). Instead, it should be regarded as a genuine strategy to extend scientific research through liberating the human resources available in civil society and fostering understanding of science through active engagement. By emphasising the intrinsic value of participation, we aim to encourage an authentic commitment from citizens, ultimately bolstering the impact and sustainability of our citizen science initiative.

Monitoring and evaluation

As we’ve already mentioned, establishing the value of citizen science initiatives in low-resource settings is vital to garner political and financial support. Although demonstrating tangible results in the short term may be unrealistic, it is imperative to incorporate monitoring and evaluation (M&E) mechanisms from the very outset. The evidence gathered from M&E processes can substantiate the benefits and effectiveness of the citizen science project, strengthening the case for continued support and investment. Additionally, the insights obtained can motivate project collaborators and citizen participants by highlighting their contributions and demonstrating the value of their engagement.

To optimize M&E efforts, an implementation science perspective addressing three primary aims should be considered. M&E should seek to understand and explain the factors that influence successful (and not so successful) implementation of the initiative; M&E should assess actual implementation practice,; and M&E should generate evidence-based guidance to refine the implementation process, enabling greater effectiveness and efficiency (Nilsen 2015).

Integration with established surveillance practices

The issue of integrating the data obtained through this novel approach with routine Ministry of Health vector-borne disease mosquito surveillance systems has been a persistent challenge. Presently, the initiative functions as a vertical project, operating somewhat independently from core surveillance systems. To fully harness the potential of citizen science data and maximise its impact, seamless integration with established monitoring frameworks is imperative.

A promising opportunity to address this challenge lies in aligning data collection protocols and harmonising data collection fields between the citizen science initiative and existing surveillance systems. By adopting standardised data collection procedures and utilising a common information management system, we hope to streamline data integration, making it easier to use citizen science–collected data as part of comprehensive analyses, and enhancing the overall effectiveness of disease vector monitoring efforts in the Solomon Islands. Given the flexibility of the citizen science model, we anticipate that it offers opportunities to strengthen surveillance interventions at sub-national levels where routine data collection is not feasible due to logistical challenges and workforce limitations.

Contribution to the SDGs

The Solomon Islands EMS project’s actions and results align, directly or indirectly, with Sustainable Development Goals (SDGs) 3, 4, and 15.

Sustainable Development Goal 3 focuses on promoting health and wellbeing for all. The citizen science project contributes to target 3.3 and 3b of SDG 3 by enhancing capacity for essential surveillance data collection required for monitoring, detecting, and responding to arthropod-borne arboviral diseases. It strengthens capacity for early warning and risk reduction locally and globally by enhancing national ability to detect and respond to emergent health threats quickly.

Sustainable Development Goal 4 emphasises the importance of quality education. While the impact of the project needs to be validated through further research, it has the potential to contribute to target 4.7 of SDG 4 by offering novel opportunities for knowledge and skill development, promoting sustainable development, and fostering lifestyles in harmony with nature. Through the provision of education-based opportunities, individuals may develop valuable knowledge about their arboviral disease risk and how to manage transmission threats leading to bottom-up action that improves health security.

Sustainable Development Goal 15 centres on protecting and restoring terrestrial ecosystems and promoting their sustainable use. The citizen science project contributes to target 15.8 of the SDG by collecting data on the presence and distribution of Aedes mosquitoes. These data play a pivotal role in informing policy and interventions to monitor and prevent the introduction, spread, and impact of invasive alien mosquito species on ecosystems, including human-inhabited environments.

Limitations

Our study is not without limitations. First, our results are based on the experience and reflections of the project team and may have benefited from broader consultation. Second, we report anecdotal evidence that the project provided a positive learning experience for students; this evidence could be strengthened through participant interviews-based evaluation research. Third, the project continues to expand, and as experience grows, so will the lessons learned.