Behaviour change interventions for the control and elimination of schistosomiasis: A systematic review of evidence from low- and middle-income countries

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Authors:
Carlos A. Torres-Vitolas , et al.

Lessons from BC approaches to control of risk behaviours for schistosomiasis prevention

The WHO considers the development of effective BC interventions critical to achieve the 2030 NTDs roadmap’s goals [11]. For schistosomiasis, changing people’s exposure, transmission, and treatment seeking or uptake practices is expected to accelerate and sustain the reduction in infection prevalence, attained mostly through preventive chemotherapy [14,15]. To assess progress on the impact of BC interventions, this review conducted a comprehensive systematic literature search, assessing 31 projects implemented in LMIC in the last three decades.

The primary objective of this review was to establish the BC strategies being implemented to control schistosomiasis transmission and their effectiveness in altering risk human behaviour. Four general intervention models were identified health education, relying on information-provision to motivate BC; social-environmental, trying to re-shape (in)formal social structures to enable and prompt BC; physical-environmental, using infrastructure and equipment investments to guide behaviour; and incentives-centred interventions, relying on conditional offers of material support. HEI was the most common approach used (n = 17). This trend likely reflects past programmatic efforts to overcome prevalent knowledge gaps among vulnerable groups and motivating support for public health campaigns, chiefly MDAs [34,85].

Despite the evidence gathered, a definitive answer concerning effectiveness remains elusive. One consideration is that the varied indicators used to operationalise risk behaviours render comparisons difficult, with some projects measuring changes in overall water-contact or open defaecation and others using disaggregated (e.g., bathing, washing, fishing) or distinct observations (e.g., urinating “in freshwater”). In addition, substantive reliance on self-reported measures, with twelve projects relying exclusively on them, raised concerns about potential bias; whilst the limited use of theoretical frameworks that explain how and why proposed interventions were expected to prompt BC made it unclear what the specific hypotheses were being tested. Observed results (Table 4) indicate that none of the intervention models identified can be singled out as the most effective in encouraging the adoption of schistosomiasis prevention measures. Promising trends were observed concerning HEIs and ICIs for treatment uptake. However, careful assessment of the advantages and limitations of each approach is needed before programmatic integration, as we discuss next.

An 2015 review of HEIs from Sub-Saharan Africa, including three BC interventions, concluded that whilst education provision improved knowledge and awareness, behavioural impacts remained uncertain [23]. This study, despite reviewing a higher number of projects, agrees with that observation. HEI projects mostly reported mixed results, apart from those pertaining to treatment uptake behaviour. The factors they identified as affecting their impact help to understand those trends. HEIs mostly attempt to motivate individuals by providing information that enhance their perceptions of susceptibility to infection, associated (non)material costs, their severity, and the benefits of prevention. Whilst knowledge-based approaches sometimes result in BC [86,87], it is seldom enough since individuals often need additional resources to redress the conditions that make certain risk behaviours common (e.g., costs associated with changing to a healthier diet) [25,85]. This was reflected in our review. HEIs often identified structural barriers, including traditional socio-cultural practices [45,51,58] and livelihoods [45,51,52,55,58,60], which affect the local use of space and so peoples’ likelihood of exposure and transmission, as well as material conditions, like availability of WASH infrastructure [45,4750,58,60,62] and the natural environment (e.g., flooding) [51,58,60,62]. Social considerations likewise matter, since risk practices are often embedded in social relations and require individuals to have sufficient agency to contravene social conventions [54,88]. HEIs working exclusively with segmented target audiences (e.g., schoolchildren), may leave some unable to alter the demands of uneducated authoritative figures (e.g., parents’ views on water-based domestic tasks).

Reports of favourable BC by HEIs, correspondingly, can be understood in relation to the absence of aforementioned barriers. Positive changes concerning transmission happened when beneficiaries were recommended to stop urinating in streams or ponds [48,58] or defaecating in agricultural fields [60], rather than stopping open defaecation altogether; all recommendations that do not demand altering economic activities, challenging social traditions, or using new infrastructure or equipment [28,89]. Positive BC outcomes for treatment uptake or seeking behaviour could likewise be associated with treatment activities characterised by free or low-cost drug provision, limited travelling demands (home- or school-based distribution), no demands for equipment (provided by control programmes), and limited challenges to socio-cultural structures [46,47,49,51,53,56,60]. It is thus recommended that future HEIs carefully map out potential barriers across all levels of analysis (individual to societal) to assess what additional components are needed to enable actors to effectively use their new knowledge.

Notwithstanding those considerations, the BC literature considers that the delivery of enticing, precise, and well-framed messages is key to prompt individuals to initiate action [28,90]. Certain pedagogical techniques appeared useful in our review: (i) (audio)visual materials, given their capacity to summarise complex information [47,48,51,71,74] and generate emotional reactions (e.g., frightening images) [71]; (ii) participatory sessions, which help beneficiaries to assess problems and outline solutions themselves, thus enhancing their confidence to take action [67,70,71,74]; (iii) context-based tailored messages, which ensure recommendations are applicable to local realities and relatable to beneficiaries’ concerns [48,51,71,74]; and (iv) enjoyable delivery platforms, like songs or games, which not only enhance their learning experience but can also attach positive emotions to safe practices (e.g., enjoyment) [47,48,71]. Mobilising trusted local figures, like school and religious teachers, has been established to add credibility to health messages [42,51,56]. Future interventions should consider making combined use of these strategies for their educational components.

SEIs, correspondingly, have the potential to tackle some challenges missed by information-based activities. That approach commonly request residents to assess local practices, outline solutions, develop action plans, and set goals [65,66,68,75]. These measures are helpful to overcome the attitude-behaviour gap hampering BC, giving individuals a clear plan on how to manage existing resources to implement recommendations and sidestep or overcome barriers [28]. In addition, by promoting community (participatory) events, mobilising leaders and associations to lead, and sponsoring new norms or standards, SEIs can foster an enabling social environment that supports rather than rejects change [43,74]. Then, social networks, social influence and pressure mechanisms, as well as governance structures synchronised with health recommendations can generate feedback mechanisms that positively reinforce BC, so that safe practices gradually become perceived as the new ‘normal’ or ‘correct’ behaviour. Widespread community mobilisation and cooperation, moreover, can help assemble local resources to support investments that cannot be otherwise made by single individuals (e.g., public infrastructure), whilst enhancing the involvement of otherwise hard-to-reach or marginalised populations, possibly leading to improved health equity [65]. Additionally, by asking residents to propose solutions and lead their implementation as well as providing training and technical support, SEIs can enhance people’s perception of their capacity to overcome barriers and achieve goals, a crucial condition for sustained BC [28].

Despite their theoretical potential, our review showed uneven outcomes from SEIs, with three of seven reporting mixed results for exposure and treatment uptake [69,71,72,74]. An important distinction between these and the SEIs reporting positive outcomes concerned the provision of technical, financial, or infrastructure support to community-led initiatives, as compared to relying heavily or exclusively on locally-available resources [63,64,66,70]. The significance of this was observed in the SEI in Mozambique, which found that lack of technical expertise and material poverty affected, respectively, the range of solutions residents could outline to deal with transmission and their ability to build the latrines initially planned [74]. Proponents of SEI, in this regard, should be mindful that NTDs are diseases of ‘poverty’, endemic to places characterised by their geographical isolation, limited access to public services, and material deprivation [11]. Debates on community-based development have long established that there is a limit to the amount of economic, social, and technical resources that impoverished communities can mobilise. Stable and formal relationships with (public) development agencies (vertical integration or ‘linking’ social capital) is required to ensure that local initiatives can take-off, be scaled-up, and sustained over time [91,92].

Programmes aiming to implement SEIs are recommended to carefully assess local socio-economic and governance conditions before deployment. This and previous reviews of SEI and community-based health promotion interventions suggest effectiveness is context-sensitive [66,74,93,94]. Weak social cohesion can affect local capacity for collective-action; inadequate governance may generate accountability problems; local forms of inequality can be reproduced in newly established organisations, whilst limited engagement with (or trust in) public health programmes can leave communities unable to formally support mechanisms to ensure sustainability.

A major barrier shared by HEIs and SEIs concerned the need for significant investments in infrastructure or equipment to support BC, chiefly for exposure and transmission behaviours [45,4749,58,67,70]. Similarly to previous studies, two main considerations were noted. One is that such investments should implement a users’ perspective to ensure adoption [43,95]. Practicality of designs, location of new facilities, demand levels, affordability, and local capacity for maintenance are all issues that require consultation with beneficiaries. For instance, if personal protective equipment hampers agricultural work, wells provide hard water that makes washing difficult, or if boreholes cannot provide the volumes of water required for bathing, associated preventive measures will not be adopted [60,76,79]. A second consideration pertains the need for comprehensive material investments. Local adoption of infrastructure or equipment may not fully support schistosomiasis control unless they are understood as part of a wider system of interconnected processes and complementary practices [19,36,96]. For instance, due to the volume of water needed for bathing and washing clothes, additional ad-hoc facilities may need to be built alongside boreholes and wells; WASH facilities in public areas, including areas of work, could be as important as in private homes, since exposure and transmission happen there; and ensuring that adequate maintenance, hygiene, and waste disposal mechanisms are in place could be as important as latrine use since transmission may still occur if infrastructure is poorly installed or maintained. Whilst technical considerations are likewise relevant to treatment uptake behaviour, the NTD’s sector decades of experience implementing PC interventions have allowed for the development of many cost-efficient solutions (e.g., dose-poles) [13,97], with further refinements in drugs and diagnostics in the pipeline (e.g. paediatric praziquantel formula) [98].

Finally, the evidence concerning ICIs remains insufficient. Available data from two projects in this study, however, coincided with trends observed by a recent review of conditional cash-transfers applied to NTDs control [99]. One is that conditional transfers appear to attain greater reach among lower socioeconomic groups but, whilst that may help to reduce health inequalities, the epidemiological contributions of those skewed effects remain unclear [81]. Additionally, to date, there is insufficient evidence to confirm the cost-effectiveness and long-term sustainability of this approach. A follow-up study for the snack-provision trial in Uganda, for instance, showed that gains in therapeutic coverage were quickly lost once food support was withdrawn [100]. Further research is needed.

In summary, evidence on the effectiveness of intervention models indicate that there is substantive need for integrated knowledge-based, social and physical environmental approaches to BC for schistosomiasis elimination. It has been proposed by various frameworks that BC is likely to occur when people have the capability (physical and psychological), the opportunity (enabling social and physical contexts), and motivation to act (through cost-benefits evaluations and emotional impulses) [28,90,95]. Integrated approaches could ensure such conditions. However, the specific combination of techniques and components to be used require preliminary assessment and planning, both to understand their contribution to the specific type of behaviour to be targeted and how local socio-cultural and ecological conditions may affect BC. In all cases, it is apparent that no quick solutions are available, BC efforts require long-term investments (Fig 5).

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