Introduction

Since 1995, the global community has been committed to reducing the impact of neglected tropical diseases on the poorest populations through the administration of preventive chemotherapy (PC) and medical care for people suffering from chronic manifestations of these diseases. Referred to as neglected tropical diseases (NTD), this suite of infectious diseases has historically not received the global attention and funding to match the significant burden of disease they exact in the poorest populations. Since 2012, the international community has agreed to the deadline of 2020 to control, eliminate and eradicate 17 NTDs. These ambitious goals are being supported by a global partnership of public, private, research and academic institutions.The history of the commitment to reducing NTDs began in the 1990s. With the establishment of the African Program for Onchocerciasis Control (APOC) in 1995 and the World Health Assembly resolution 50.29 which committed to eliminate lymphatic filariasis (LF) as a public health problem, global attention increased for these two diseases. The elimination of LF and onchcocerciasis has been facilitated by massive and long-term donations from pharmaceutical companies to provide the drugs required for mass drug administration (MDA) to people living in endemic regions (Mectizan by Merck, Albendazole by GlaxoSmithKline and Diethylcarbamazine citrate by Eisai Pharmaceuticals). As potential for success was achieved in the elimination and control of onchocerciasis and lymphatic filariasis, additional NTDs were slated for control and elimination through preventive chemotherapy, namely schistosomiasis, trachoma and soli-transmitted helminthiases (STH). With that decision, additional drug donations of Mebendazole (Johnson & Johnson), Praziquantel (Merck) and Azithromycin (Pfizer) were secured to support NTD programmes. In 2012, The London Declaration was signed documenting a unique and unprecedented partnership of governments, industry, academia, non-governmental organisations (NGOs) and donors, all united to support the eradication, elimination and control of NTDs in alignment with the World Health Organization (WHO) 2020 Roadmap on NTDs [www.unitingtocombatntds.org].

Significant public health gains have been made and documented in the process to reduce the transmission and impact of PC-NTDs, specifically those NTDs that respond to preventive chemotherapy and include: lymphatic filariasis; schistosomiasis; onchocerciasis; trachoma; and STH. By the end of 2014, APOC reported that 65% of the population living in onchocerciasis endemic regions in Africa had received ivermectin.[1] It is estimated that by the end of 2015, APOC had saved 17.4 million Disability Adjusted Life Years (DALYs) in its 20 years of existence.[2] The Global Program to Eliminate Lymphatic Filariasis (GAELF) was launched in 2000. Between 2000 and 2014, the program delivered 5.6 billion treatments to 763 million people living in endemic regions, saving an estimated 175 million DALYs.[3] The economic gains of reducing LF in the first eight years of the program (2000–2007) are estimated as US $21.9 million in direct economic benefits and approximately US $2.2 billion in savings for health systems due to the decreases in services needed for LF patients[4]. Schistosomiasis control has been successful in a number of countries, however it remains a major contributor to suffering for people living in tropical regions where the disease remains prevalent.[5] The estimated DALYs lost from schistosomiasis is 24–27 million, with the highest burden of disease in Africa.[5]

The public health gains of the NTD platform are noteworthy and the cost of delivering these programs is considered inexpensive, in part because of the role of volunteers. A recent review confirmed that the cost of delivering treatments for six PC-NTDs is estimated to be less than $0.50 USD per person treated, except where programs cannot rely on local volunteers.[6] With all of the noted public health gains that have been demonstrated since the beginning of the global focus on NTDs, it is important to acknowledge the crucial role that local volunteers play in the implementation of these NTD elimination and control programs. Known by different names—community drug distributors (CDDs), NTD volunteers, health extension worker, community health workers (CHWs), health assistants or health army—their role is the same: to ensure that each person eligible to receive PC treatment for NTDs takes the drugs as per the protocols. The participation of these community volunteers reduces the costs of NTD control and elimination as well as provides an effective way to reach endemic communities.

Community drug distributors rose to importance within APOC, when the community directed treatment with ivermectin (CDTI) was initiated.[7] Communities were responsible to select volunteers who would conduct census activities, social mobilization and drug delivery ensuring that they reached all eligible community members. With CDTI, a massive volunteer workforce was mobilised. In 2013 alone, 517,000 CDDs were trained through APOC.[1] Subsequent NTD programs have adopted the use of community volunteers to deliver drugs to their fellow community members under the supervision of the primary health care system and other local organizations.

A recent review by Corley et al (2016) remarked on the importance of CDDs in motivating and educating communities for sustainability and uptake of NTD activities. They are considered a “valuable human resource” and program managers should recognise their contribution while acknowledging the risk that these NTD volunteers can also inhibit programmatic achievements.[8] Many reviews of compliance and coverage of MDA programs cite the role that NTD volunteers play, both as positive and negative influences on programmatic outcomes.[9] Within the context of delivering drugs for the MDA for LF, some of the positive ways that NTD volunteers impact coverage and compliance include: being familiar to community members; taking the drugs themselves in front of community members; and visiting a household prior to drug distribution.[9] CDDs can also negatively impact the coverage and compliance with MDA activities for LF elimination by having poor motivation and poor communication skills.[10] In onchocerciasis programs, community perception of the drug distributor has been shown to influence uptake of the pills.[11–13] In a study on schistosomiasis control in Kenya, community members reported that they did not feel comfortable being treated by a non-medical person and by someone who did not have a certificate to demonstrate his/her knowledge or training in the disease and treatment. The CDD has not always been adequately supported by the health system so that s/he can carry out the activities sufficiently, thereby negatively affecting the uptake of praziquantel in this study.[14]

While the critical importance of CDDs is essential to the successes of NTD programs, much of our understanding of their role comes from the earlier days of the programs. The social, cultural and programmatic landscape have changed with potentially consequential effects on the acceptance and performance of the volunteers. NTD programs began as single disease vertical programs (APOC, GPELF) but now have been integrated at the global, national and community levels to maximise delivery and funding platforms. With this integration, the role of communty drug distributors is more signficant as these individuals are now responsible for delivering multiple drug combinations, maintaining different reporting forms and communicating at different intervals throughout the year with their communities. To date, we do not fully understand how this increase of responsibilities has impacted the motivation and retention of these volunteers.

The cultural landscape in many of these communities has also changed, with the increase in mobile telephone technology and urbanization for example. The impact of technological and other socio-cultural changes on the motivation and performance of volunteer community drug distributors has not been fully explored. Do the often-used traditional forms of incentives (t-shirts and badges) work in a more sophisticated environment? Additionally, many communities have now had multiple rounds of MDA, and community fatigue with MDA has been anecdotally reported. Finally, community members are no longer seeing the manifestation of the NTD diseases as they previously saw, thereby potentially reducing the urgency of compliance. How might these changes in the community perception of NTDs and their elimination affect the motivation of the CDDs?

This paper seeks to review in a systematic manner the current literature examining the motivation, retention and performance of CDDs for five PC diseases (trachoma, onchocerciasis, LF, STH and schistosomiasis). For the purposes of this paper and due to the many different names used for these individuals, all CDDs will be referred to as NTD volunteers.

Methods

Data collection and analysis

Two reviewers independently tested the data extraction form (Table 1) using a random sample of about 10% of the included studies. This process enabled necessary revision to establish reliability for independent data extraction. Full data extraction was then performed for all papers using a Microsoft Excel database. This included information on study design, country, NTD program, factors relevant to NTD volunteer participation, incentives and motivation, performance or satisfaction as described above. These data were then pooled and examined for themes. The themes identified included monetary and material incentives, intrinsic motivation, gender, cost to participate, health system and community support. Data were then re-categorized based on these themes and summarized.

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Table 1. Example of data extraction table.

https://doi.org/10.1371/journal.pntd.0006065.t001

Results

A total of 28 studies were included in the final review (Fig 1). Most of the included studies were performed in Africa (Fig 2) with studies based in Uganda (31%) and Nigeria (20%) being the most common. Various study designs were represented; however, interviews (34%), focus group discussions (23%) and surveys (23%) were most common (Fig 3). Many studies employed mixed methods study designs. The majority of studies came from onchocerciasis (54%) programs, followed by lymphatic filariasis programs (16%, Fig 4).

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Fig 1. PRISMA flow diagram.

https://doi.org/10.1371/journal.pntd.0006065.g001

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Fig 2. Percentage of publications by country.

https://doi.org/10.1371/journal.pntd.0006065.g002

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Fig 3. Percentage of publications by study design.

https://doi.org/10.1371/journal.pntd.0006065.g003

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Fig 4. Percentage of publications by NTD.

https://doi.org/10.1371/journal.pntd.0006065.g004

The data from the papers can be grouped into the following thematic areas: monetary and material incentives, intrinsic motivation, gender, costs associated with participation as an NTD volunteer, health system factors (training, supervision, workload, timing, definition of roles) and finally community support. Each of these themes will be developed in more detail below.

Discussion

The indispensable role of the NTD volunteer to the success of control and elimination goals is certain. Through their work globally, these volunteers have brought life-saving and health-improving care into the homes of billions of people for decades. For these reasons it is critically important that we understand how these NTD volunteers are presently motivated and how their performance can be sustained and improved, particularly as the timeline of 2020 approaches. This review compiles the literature specific to the motivation and performance of the NTD volunteers across five PC diseases and offers some insight into the key thematic areas affecting motivation and performance.

NTD programs are not unique in their use of volunteers for community outreach and service delivery. Like the community health worker (CHW), the NTD volunteer is not always remunerated for his/her work, is not a formal part of the health system and is often the direct link between the health program and the community. In many instances, NTD volunteers are CHWs, carrying out other health activities in the community. This review highlights some of the challenges that face volunteers in their work in NTD control and elimination. The interaction between the involvement of the volunteer in community health activities, other than NTD activities, was not a predominant theme that emerged in this review. Many of the thematic areas identified in this review echo other findings from research focusing on community and lay health workers.

Intrinsic motivations, for example, are not unique to NTD volunteers and have been shown in CHWs as well. A Cochrane qualitative evidence synthesis described how lay health workers from low, middle and high income countries were motivated by altruism, social recognition and improved knowledge. The authors also highlighted the contradiction that exists between lay workers’ views on incentives: some wanted regular payment while others were happy to volunteer without financial incentive.[41] Kane et al (2016) in their review of CHW empowerment in six countries reported on some of the positive intrinsic motivations of CHWs like being called a doctor and being trusted by the community. They also mentioned the value of improved competency, particularly for curative tasks. [42] Given the consistency of intrinsic motivation as a theme across various NTD studies, programs would benefit from identifying ways to reinforce these values. One suggested method is to increase community appreciation for NTD volunteers. Community members should understand that volunteers are not receiving a salary for their service, hopefully increasing assistance for volunteers as well as gratitude. This may be especially relevant in some communities where individuals believed that volunteers were being paid.[28] Another suggestion is to institute ways for the health service and community to publicly recognize the NTD volunteers’ work and contribution.

Studies from other fields also describe factors related to low motivation of health volunteers that are similar to what has been described in the NTD literature. A study of health promotion volunteers in Japan found that volunteers with low motivation also reported uncooperative neighbourhood associations.[43] Another demotivating effect for CHW was when materials were not available for fieldwork and when supervision focused only on reporting forms. [42]

The literature on motivations, incentives and performance of community and lay health workers is more substantial to what has been documented about NTD volunteers. One of the key differences between the NTD literature and the general health literature is the limited amount of evidence of the impact of community or lay health workers on the health of the populations they serve. For certain areas, like pneumonia and diarrhea, there was little evidence of CHW impact. [44] However, a larger impact has been demonstrated where CHWs were engaged in delivering insecticide treated nets and malarial chemoprophylaxis as shown in a systematic review from sub-Saharan Africa. [45] In NTD programs, the NTD volunteers have a clear impact on programmatic outcome, as they provide the most efficient mode in which to deliver drugs to the community.

One of the areas identified in this review is the impact of the health system on the NTD volunteer. The health system, usually at the district level with the support of frontline health facilities, is responsible for training, supervision and providing the material support for NTD volunteers so that they can perform their activities in the community. The health systems in the countries where NTDs are endemic are often constrained by insufficient funding, limited human resources, insufficient management and poor governance.

Evidence shows that vertical disease control programs can further strain already weakened health systems, [46–48] suggesting that NTD programs have not played a strong role in strengthening health systems. NTD volunteers experience health systems challenges in the execution of their duties. For example, when training is inadequate to meet the needs of volunteers, support for adverse events is insufficient or when supplies do not arrive in time for program activities, the challenges of the health system become the challenges of the NTD volunteer. Therefore, identification of solutions to these issues requires a systems approach, something that global health initiatives, like NTD control and elimination, have not always considered and have sometimes even resisted. The way forward to sustain and improve motivation of NTD volunteers must be accomplished within the framework of health systems. NTD programs provide excellent opportunities for health systems strengthening,[49] however it is rarely the expected output of program activities.

Better integration of NTD programs into health systems is seen as a critical way to ensure sustainability of the gains made in the NTD elimination program as well as to improve impact of elimination activities by integrating the NTD program into existing activities. Integration in the health sector has been variously defined and applied to achieve ends broadly conceptualized as reducing fragmentation and duplication of interventions to achieve a continuum of health care, ease of access, improved health outcomes, wide population coverage, user satisfaction and efficiency. [50–52] The one-stop shop health care service, the delivery of multiple population based interventions on a single platform for efficiency and improved population coverage and a process where disease control activities are functionally merged or tightly coordinated with multifunctional health care delivery are all forms of integration. [53–58] In many countries, it is at the lowest level of program implementation that the most integration occurs especially if the service providers have the flexibility of managing their own resources. In a study by Mensah et al (2016) on the level of integration of the NTD program into the regular health system, the authors indicate that the level of integration was much higher at the district level compared to the national and regional levels.[59] This was because the District Health Management team (DHMT) operated an integrated unit coordinated by the District Director of Health Service.

Although there has been an increase in the number of countries integrating community-based health workers, including the NTD volunteer, into the health systems, a systematic review on the integration process of national community-based health worker programs into health systems in low and middle income countries showed that integration has not been optimal. This is because integration has been influenced by levels of trust, appreciation and support by community and family members as well as the attitudes of professional health workers.[41,60] For sustained success of NTD programs, there is a need to critically look at proper integration of community health workers, like NTD volunteers, into public health programs at the lowest level of health care delivery as well as encourage a national priority to ensure efficiency and better delivery of health services. The NTD volunteer workforce has enormous potential for other public health activities. This should encourage the process of better integration of this workforce into the health system to strengthen the delivery of public health initiatives at the community level.

An additional recommendation to reduce the added pressure on health systems is to ensure better coordination between global health initatives to allow for better synergy between horizontal and vertical programming.[61] This coordination ideally should occur at all levels, from the level of global donors through to the actors at the community level. We know that integration at the national level is largely dependent on the strength of the health system itself to deliver its programs and as such, integration may be more feasible in some national contexts as opposed to others. [62] A functioning integrated system is expected to increase efficiency of program delivery and has the potential to aid NTD volunteers in their work by improving supervision, clarifying reports as well as ultimately decreasing the amount of time they are required to spend away from their other household responsibilities. This may also improve CDD satisfaction by reducing comparisons between programs. Differences in donor-directed payment of incentives has been shown to cause dissatisfaction; this is particularly relevant since geographical overlap of programs is quite high.[63]

Another challenge that has been highlighted in NTD programs is the multiple years that volunteers have been engaged in program activities. Many MDA programs for LF have progressed to more than six rounds, and for onchocerciasis, more than 10 years, creating fatigue for the health providers, NTD volunteers and the communities at large. This prolonged use of volunteers has had the benefit of mobilizing and training thousands of people for health. However because the end date of many of these MDA programs is unknown, volunteers express weariness and discouragement as their tasks continue on year after year. In addition, for the NTD volunteer who started with once yearly MDA for LF or onchocerciasis, his or her tasks now comprise a suite of activities including drug delivery for multiple diseases at different times of the year. The literature on this is mixed, as seen in those papers citing that volunteers feel overwhelmed by the workload and the short time they have to complete their duties, while other researchers have reported that the increase in workload has had a beneficial impact on the NTD outcomes. Better understanding is needed on the impact of this programmatic transition for the volunteer and on how to more effectively introduce changes to their training and routine tasks.

One of the important findings in this review is the significance of community support on the motivation and performance of the NTD volunteer. Volunteers come from the communities that they serve and the literature supports the need for these communities to be engaged and cooperative when the volunteers carry out their work. This means ensuring that communities understand the importance of the goals and benefits of the program, that they are engaged with the efforts and that they are part of program implementation especially when and where distribution will occur. When the support of the community is not present, the effect can be demotivating for the volunteers. As the NTD programs in many countries progress, the community engagement process should also evolve sufficiently to support elimination efforts. Communities should know program successes and understand program planning with regards to transmission assessments and stopping MDA. In communities where MDA programs have existed for many years, people no longer see disease in the same way that they did at the start of these programs, thus lessening community perception of risk. New messages will help communities to see their successes, but also recognize the need for sustained support until transmission is interrupted. Good community engagement practices can impact directly the work of the volunteer, providing the reception and affirmation he or she needs to carry out drug distribution, referrals for adverse events, and reporting. Any solution to improve and sustain the motivation of the volunteer must take into account improved community engagement, particularly in the “older” campaigns. This could be done by involving the community in reaching targets by allowing them to identify appropriate CDDs, testing MDA messages and involving key community leaders and existing groups in the MDA program. The hypothesis being that engaged communities should enhance volunteerism. Recent research by Chami et al[64,65] underlines the power of understanding and utilizing social networks in relation to CDDs in MDA planning and implementation. It was shown that people with many social connections and in a central location were more likely to be offered the MDA. In another paper, Chami found that certain groups of people may be less likely to be approached during the distribution.[66] By combining knowledge of non-recipients and social networks, villages may be able to identify CDDs who would be able to reach a greater proportion of the population.

The review has highlighted some of the out of pocket expenditures that volunteers have in their activities. While the average cost per NTD treatment has been reviewed recently (Fitzpatrick et al 2016), the authors note that few cost studies included in the systematic review and model provided information on the opportunity cost incurred by volunteers or the out of pocket expenses that some volunteers incur. The cost of $0.50 per treatment that is often used in NTD advocacy does not include the cost of volunteers. Fleming et al (2016) provide one of the only recent studies that have addressed volunteer costs. These costs, both economic and financial, must be considered in order for the NTD programs to not burden the volunteers and communities with unsustainable costs, particularly as the intensity of the end game for NTDs becomes more salient.

Increasingly, the impact of gender on health has been highlighted as crucial in our ability to understand the local context. This review has demonstrated that the experiences and performance of male and female volunteers are not the same. Female volunteers have been shown to be patient and conscientious; however there can be limitations on their ability to work due to household responsibilities and cultural constraints. Better understanding of these differences would help national programs to equip their NTD volunteers more effectively, knowing that the constraints and opportunities may be different according to the context. For example, how could female NTD volunteers be better supported in their work in the field? How can some of the skills attributed to female NTD volunteers be incorporated into the training of all NTD volunteers?

One of the limitations of this review is that most of the included papers center their research on the African context. This underscores the history of the CDD, which is rooted in the CDTI approach which was introduced and supported by APOC. In addition, it may reflect the use of more primary health care personnel in drug distribution in other regions as compared to community volunteers. [67] However, it also suggests that there is a dearth of research into the motivation and performance of NTD volunteers from other countries where these programs are ongoing and still expanding, namely South Asia, Southeast Asia and the Western Pacific regions. Another challenge is the limited evidence of the impact of gender on the volunteer. Although some papers do acknowledge gender in their reviews, it is not systematically included in the assessment of volunteer performance and motivation. Perhaps with a renewed interest in gender and NTDs, future research will provide a gendered approach in their analysis of these issues.

Conclusion

This review has highlighted the need for more research on the role of incentives in motivation, retention and performance of community volunteers. The literature on volunteer motivation and performance is minimal, particularly outside of the African context and with regards to gender. Some of the literature reviewed demonstrates the link between improved drug coverage and some of the thematic areas covered in this paper, but these links tend to be anecdotal and limited by geographical boundaries. To show a definitive association between the introduction of a certain incentive or training program for NTD volunteers and improved drug coverage would be challenging due to the constraints of conducting research in non-controlled environment. As such, there is a need for more implementation research to demonstrate the utility, acceptability and feasibility of measures to improve NTD volunteer motivation. Any initiatives to improve and sustain motivation of NTD volunteers must be considered within the lens of the health system and changing sociocultural environment. This allows for a clear understanding of the local context and the possibility to adapt the training, supervision and incentivization of volunteers. Furthermore the gains of the NTD program can be sustained for use in other public health programs.

The use of NTD volunteers to date has appeared “free” until recent research elucidating their opportunity costs.[15] The NTD community needs a better understanding of the true costs that these volunteers bear by virtue of participation in the program, including the out of pocket expenses. Without a full understanding of these costs, the real value of the volunteer will be underestimated.

Finally there is an urgent need to identify effective resources and novel approaches to better equip NTD volunteers. The NTD program can learn from other health programs in the use of mobile phone technology, radio and theatre, for example, to reflect changes in the ways that communities receive information in a changing socio-cultural environment. As 2020 approaches, it is clear that the goals will not be met without the full support and cooperation of this NTD volunteer workforce.

Supporting information