Designing More Effective Dengue Control Programs – Colleen Longacre

Designing More Effective Dengue Control Programs – Colleen Longacre

Dengue is a mosquito-borne infection that causes severe flu-like symptoms and can give rise to a deadly complication called dengue hemorrhagic fever (DHF). Dengue is found in tropical climates worldwide, and DHF is the leading cause of death among children in some Southeast Asian countries (1). The global incidence of dengue has increased dramatically over the past 30 years, making it a major international health priority. Because there is currently no vaccine and no specific treatment for dengue, public health programs have focused primarily on vector control programs that target the mosquitoes that carry the virus. Early control programs were vertical in nature and focused on large-scale chemical spraying of standing water sources. When these efforts alone proved ineffective, public health professionals stressed the importance of community-level campaigns to promote behavior change to promote vector control. However, these community campaigns have been designed primarily using the Health Belief Model and other individual-level models of behavior change. As a result, these campaigns have also failed to inspire community-wide behavior change and decrease the incidence of dengue among the populations at risk.

Components of Current Community Vector Control Programs

Community-level vector control programs are comprised of three elements – insecticide application to potable water supplies, environmental management, and community awareness campaigns. The World Health Organization (WHO) currently approves five insecticides for use in drinkable water. In addition, biological control agents, such as larvae-eating fish, may be introduced into water supplies to kill the mosquito larvae without adversely affecting human health (2). Environmental management consists of clean-up campaigns, installation of water supply systems, solid waste management, and better urban planning (2). Campaigns designed to raise community awareness and participation in vector control efforts are the newest addition to these programs. These campaigns seek to increase control activities at the household level, such as “covering or frequently cleaning water storage vessels, removing discarded food and beverage containers, and disposing of used tires in such a way that they do not collect rainwater” (2).

The Health Belief Model has been widely used in designing these campaigns. The Health Belief Model, one of the most widely used individual behavior change theories in public health, states that health behavior is primarily motivated by four factors: perceived susceptibility, perceived severity, perceived benefits of an action, and perceived barriers to taking that action (3). This model assumes that an individual rationally weighs the costs and benefits of taking action and then acts (or chooses not to act) according to whether or not the benefits outweigh the costs. Additionally, individuals respond to specific cues to action to initiate behavior change, and will take action only if they feel they have a certain degree of self-efficacy in taking that action (3). Recent dengue control campaigns have attempted to address each of the elements of the Health Belief Model. One organization working in dengue control published a bulletin of targeted messages for NGOs to take back to the communities in which they work. These messages addressed perceived susceptibility and severity (“So, you don’t think that dengue is a real problem? It is here in our community now! Young and old get sick with dengue.”), perceived barriers (“Little time to do clean-up to reduce mosquito breeding sites? No problem! Use the action plan checklist. Use it once a week.”), and perceived benefits (“If everyone spends just a few minutes each week to clean up stagnant water, throw away unneeded containers, or cover them, then it will go a long way to reduce dengue fever.”) (4). The inclusion of these messages in posters and public service announcements is designed to serve as the cue to action.

Although these vector control programs have attempted to engage with communities and have recognized the importance of widespread behavior change on program effectiveness and sustainability, their results to date have been unremarkable (5). Several flaws in the design of these programs are impeding their success in reducing the incidence of dengue throughout much of the world.

The Health Belief Model is an Inadequate Predictor of Individual Behavior

The awareness-raising element of vector control programs assumes that individuals are unaware of their susceptibility to dengue fever and the severity of the disease. However, community-level studies conducted in South America and Southeast Asia have proven that this is not the case. One study in Brazil, for example, found that 95% of the population recognized dengue as a severe illness, and 75% had either a relative who had suffered from dengue in the past or had suffered it themselves (6). In addition, 94% of the population could identify at least one method of vector control (6). However, only 18-31% of the population actually reported employing methods of vector control (6). Similarly, in Cambodia, a study among primary school students found that 73% could identify the cause, symptoms, and consequences of dengue, and 83% could identify at least one method of vector control (7). However, when researchers examined the households of these students, they found that few employed vector control strategies (7).

These findings are at odds with what is predicted by the Health Belief Model. Among these communities heavily affected by dengue, there is apparently widespread awareness of the susceptibility and severity of the disease. There is also seemingly widespread knowledge of the desired action and the benefits of that action. Mass communication campaigns have attempted to reduce the perceived barriers through easy-to-follow checklists and action plans. However, the use of vector control strategies remains low.

The failure of the awareness-raising campaigns to inspire actual behavior change exposes critical shortcomings in the Health Belief Model approach. Most importantly, the Health Belief Model assumes that everyone has equal access to, and an equivalent level of, information to make rational decisions. In developing countries and especially in rural communities, access to information is not uniform. In fact, both the campaigns themselves and the studies conducted to evaluate them may have missed their target completely. In many communities, elderly women are primarily responsible for household tasks such as cooking and cleaning. These women should be the primary targets of any intervention designed to encourage the regular cleaning and covering of water containers and the proper disposal of garbage; however, they are also the least likely to be literate or to be exposed to outside media sources that promote such behaviors. Furthermore, school-aged children and adult members of the household who are exposed to the awareness-raising campaign may feel it is outside their sphere of influence to instruct their mothers or mothers-in-law as to how they should carry out their daily tasks (8). As a result, there is a significant disconnect between those with the information and those with the self-efficacy to enact behavior change that stems from the roles different individuals play within the greater household dynamic. The Health Belief Model fails to take into account these social factors that inform individual decision-making. To develop more effective community vector control programs, public health practitioners should consider alternative behavior change models that address these social issues.

Environmental Management Strategies Fail to Take into Account Maslow’s Hierarchy of Needs

As previously discussed, the environmental management component of vector control programs consists of mass clean-up campaigns, installation of water supply systems, solid waste management, and better urban planning (2). However, the provision of these services requires considerable investment in the overall public health infrastructure of many communities. In order to recoup this investment, cost-recovery mechanisms have been introduced into many communities (2). In rural areas, environmental management often takes the form of the installation of metered community water services, whereby each household pays for the amount of water they extract from a common, certified clean source. In effect, the households are asked to pay for the assurance that they will not contract dengue from their water supply. Mass clean-up campaigns have aimed to eliminate sources of standing water that serve as breeding grounds for mosquitoes. These sources include old tires, wheelbarrows, tin cans, and oil drums that household members may leave around their property (9). Clean-up crews offer to remove these items at no cost to the households.

While these environmental management strategies would be effective in reducing the incidence of dengue, they have been met with extensive resistance from communities. Among some poor communities in Southeast Asia, households resorted to collecting rainwater from roof catchments at no cost, rather than paying for the use of community water supplies. Contrary to its intent, the introduction of community water services has actually increased the incidence of dengue in certain areas (2). Similarly, communities were unwilling to allow clean-up crews to remove tires from their property, because they used these tires during the windy season to anchor the tin roofs of their houses to keep them from blowing away (9).
The response of poor communities to the environmental management strategies is a clear expression of Maslow’s hierarchy of needs. Psychologist Abraham Maslow theorized that all human beings desire to grow and attain their full potential; however, before human beings can pursue any kind of higher-level growth, they must be able to satisfy a set of needs (10). According to this theory, safety of health is a higher-order need than the basic needs of water and housing. Until these basic needs are met, individuals are unlikely to focus on their higher-order needs. Therefore, even if individuals recognize the importance of dengue control, they will value their access to free water and secure housing more highly than they value the implementation of vector control strategies. Public health practitioners must consider alternative strategies of environmental management that either do not disrupt people’s ability to meet their basic needs, or are able to meet them simultaneously.

Some Insecticide Treatment Practices are Not Culturally Acceptable in Communities Where They are Employed

The use of insecticides to treat water supplies has long been the primary means of vector control in dengue campaigns. Households are encouraged to add insecticides to the stored water supplies they use for drinking, cooking, and bathing. These insecticides have been certified by the WHO as safe to ingest, and there are no documented adverse health effects of adding these chemicals to the water supply. However, despite these assurances, many communities disapprove of the use of these insecticides for cultural reasons.

Anthropologist Linda Whiteford studied what she describes as the “indigenous typology of water” in the community of Villa Francisca in the Dominican Republic (8). Because water is a scare commodity in this community, different water from different sources is used for different purposes. Tap water is generally brackish and slightly sour, so people prefer to use this water for cleaning. For drinking and cooking, people relied on so-called “sweet water” purchased from public water sources. The idea of adding chemical agents, which slightly altered the taste of the sweet water, was considered ridiculous. Why would they “unsweeten” the water that they had paid for? Similarly, agricultural communities in Central and South America have been resistant to adding chemicals to their drinking water supplies, in part due to public health campaigns in these regions designed to alert farmers to the dangers of pesticide poisoning. Farmers reported that “[the insecticides] had bad smells, so must be harmful to the health”, because this was how they were taught to identify water that might be contaminated with harmful agricultural pesticides (6). Finally, the use of biological control agents has met with resistance in Southeast Asian countries such as Thailand, where there are strict cultural taboos about bathing with water that contains small fish or other creatures (2). For insecticide treatment programs to be effective, public health practitioners must take into consideration the cultural beliefs and practices of the communities in which they work. They must demonstrate an understanding of current community behaviors before they attempt to induce behavior change.

In the absence of the development of a dengue vaccine, vector control programs remain the most important public health intervention in reducing the incidence of dengue worldwide. By reworking the awareness-raising campaigns so that they target the appropriate audiences, by addressing the effects that changes in public health infrastructure have on the ability of households to meet their basic needs, and by understanding the cultural significance of adding chemicals to water supplies in certain communities, vector control programs will be able to more effectively combat dengue around the world.
Dengue Control Programs Must Engage with Women to Raise Awareness at the Community Level

As previously discussed, there is a significant disconnect between those exposed to current awareness-raising campaigns and those with the self-efficacy to enact the behavior changes necessary to achieve the desired outcome. In order to be more effective, awareness-raising campaigns need to be retooled and redirected. One lesson of the failed campaigns is that it is not the message itself that is the problem. Previous studies have shown that those who were exposed to the message both understood the problem and the necessary course of action to take to fix the problem (6,7). What needs to change is how the message is being disseminated into communities and who is being targeted to receive the message.
Social Networking Theory provides a framework for how this goal might be achieved. Social Network Theory first emerged in the 1950s and has been applied in the diverse fields of sociology, public health, communications, political opinion, mathematics, and systems theory (11). Social Network Theory operates on the assumption that the specific and unique characteristics, beliefs, and attitudes of individuals are not as important as the relationships between and among individuals. The theory posits that it is the nature of those relationships (i.e. family/kin networks, work networks, social groups, etc.) that most influences beliefs and behavior (12). Social networks play an important role in whether individuals adopt specific health behaviors, what information individuals are exposed to concerning their health, and what kinds of social support and coping mechanisms are available to individuals (13).

Researching a community’s social networks would provide public health practitioners with information regarding who the primary targets of their awareness campaigns should be. If they had examined family dynamics in many rural communities, they would have learned that it is the mothers and grandmothers who most need to be exposed to information concerning vector control. Once the targets of the message have been identified, Social Network Theory provides a mechanism for effectively disseminating the message. Public health practitioners identify those women who are central to most of the social groups at play in the community. By engaging with these influential women, public health practitioners will build credibility at the community level for their proposed program. Public health practitioners could host small group discussions with these women, and then encourage them to organize discussions with other members of their social networks. In this manner, the vector control message will eventually trickle out to even the most marginalized members of the social network, and the community will feel a sense of ownership over the message. This sense of ownership increases individuals’ self-efficacy and may encourage more universal behavior change. Moreover, the existing social networks can act as built-in mechanisms of social support – neighbors can check in on each other to ensure that they continue to employ vector control strategies.
Dengue Control Programs Must be Integrated into Broader Development Projects

Environmental management is an important component of dengue control programs; however, it cannot be implemented in a vacuum. More effective environmental management programs would take Maslow’s hierarchy of needs into consideration in their design and implementation. Before public health practitioners decide to install metered community water pumps or organize mass clean-up campaigns, they must first evaluate the ability of communities to cope with these changes. If the average household income in a given community is less than a dollar a day, charging fifty cents for clean water may not be the most effective method of dengue control for that community. If communities cannot afford to pay for clean water, then clean water must be made available to them by another method. Similarly, cleaning crews that offer to remove tires should also be equipped to offer to reinforce roofs by another method. Public health practitioners working on environmental management projects should interface with other organizations doing development work in the communities to ensure that individuals’ basic needs are being met and that they are being provided with alternatives for the behaviors and practices they are being asked to abandon.

Dengue Control Programs Must Utilize Culturally Appropriate Water Treatment Methods

As previously suggested, for insecticide treatment programs to be effective, public health practitioners must take into consideration the cultural beliefs and practices of the communities in which they work. They must demonstrate an understanding of current community behaviors before they attempt to induce behavior change. Cultural theory provides an invaluable tool for addressing these issues. Cultural theory “informs us that we live and behave in subjective worlds of meaning, where behavior and meaning are linked” (14). Decoding the meaning behind behaviors is essential to explaining why individuals are resistant to certain behavior changes. More thorough research is necessary before dengue control programs are introduced into communities. Public health practitioners must be willing to conduct literature reviews of the work of cultural anthropologists in the area, or, alternatively, be willing to employ cultural anthropologists as integral members of their program teams. By incorporating cultural theory, dengue control programs can ensure that insecticides are introduced to communities in ways in which it is more likely to be accepted.

If public health practitioners in Villa Francisca, for example, had been aware of this community’s indigenous typology of water, they could have predicted that simply dispensing insecticides in the community would not induce people to use them. If these practitioners had been familiar with Dr. Whiteford’s research, they could have employed this information in developing their awareness-raising campaigns. They could have reframed the concept of adding insecticides to sweet water as a means of enhancing this water even further by adding a life-saving substance to it, not as a method of unsweetening the water. Similarly, if public health practitioners had known about the cultural taboos in Thailand, they would have invested their resources in procuring chemical insecticides rather than biological control agents for these communities. Ensuring that water treatment methods are culturally appropriate may require more initial research and expenditure of resources during program development; however, dengue control programs that fail to do this run the risk of wasting even more time, effort, and resources on unsuccessful programs.

Dengue is a critical international public health problem that deserves well-designed, well-implemented control programs. Past and current dengue programs have been successful in determining what methods of control are most effective; however, they have been largely unsuccessful in inspiring communities to adopt these methods of control. By utilizing social science theories, such as Social Network Theory, Maslow’s hierarchy of needs, and Cultural Theory, dengue control programs will be able to more effectively target the appropriate audiences, ensure that programs are not disruptive to the overall health and wellbeing of communities, and ensure that water treatment methods are culturally appropriate. The combined effect of these improvements should serve to inspire more widespread behavior change and to begin to reduce the incidence of dengue worldwide.

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