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La lutte antivectorielle en France

 | 
Didier Fontenille
, 
Christophe Lagneau
, 
Sylvie Lecollinet
, 
et al.

Implementation of vector control

Perception of risk in relation to vector control communication1

Texte intégral

  • 1 In this chapter, references to the CD-ROM concern question 6: “Perceptions and information-educati (...)

1What information, education and communication networks exist concerning vector control? How do communities accept such campaigns and perceive their efficiency? These are two key questions. But they cannot be considered separately owing to their strong interdependence: this is one of the hypotheses set out in what follows.

2Vector control is the principal or even the (only) means of protection against any form (whether endemic, epidemic or emergent) of vector transmission of pathogens. However, how it is perceived is greatly dependent on the perception of the risk of vector-borne infectious disease itself. Any kind of communication must take both into account: the way the protective response is perceived is heavily influenced by the perception of the risk itself.

OVERVIEW OF PREVAILING CONCEPTS

Perception of vector control

3This relates to two distinct ideas: the perception of its utility/efficiency against the vector and that of its acceptability. Vector control in fact is or can be seen as itself carrying risks to health and the environment or even disadvantages and excessive costs, whatever technique is employed. This touches on the notion in the English-speaking world of risk trade-off, which expresses this link between the risk from the vector and the risk from control measures against it. It is essential to take this element into account for devising any vector control action and associated communication activity. It is still more significant a factor in situations where vector risk has not been proved, even if generally anticipated, and when a vector control campaign is planned in order to prevent.

Communication

4Whether its approach is informative, educational or different, communication aims to instil in the target publics effective, efficient protective behaviour in the face of identified risks. With regard to this objective, the juxtaposition of the three notions – information, education, communication – in a single symbolic acronym, IEC, can cause confusion. The ideas of ‘information’ and ‘education’ can be interpreted as knowledge and practices handed down, justified by some cognitive deficiency, not always clearly identified, that has to be filled. Communication refers to an approach or interactive generic method by means of which different messages or incitements can be conveyed, circulated and made significant. In other words, although partly informative, communication can seek to incite feelings (fear, desire, social conformity and so on), arouse interests, without in any way having an “educational” tone. Nevertheless, the objective is the same: win the observance of certain protective behaviour. Nothing can predict in advance the kind of motivation, depending on the situation, that will be the most effective.

MESSAGE DEFINITION

5The historical and socio-cultural context of a communication campaign, and also the epidemiological situation in which it is run (emergence, epidemic, endemic, or strong suspicion of disease) and the nature of the vector system concerned play a decisive role in the perceptions held about risks from vectors and from control measures against them. The choice of messages must therefore take them into account.

6In general, determination of the objective and content of the communication campaign must be founded on an as accurate a knowledge as possible of the perceptions, representations, knowledge, beliefs, values and practices of the populations exposed to vector risk and affected by vector control. A number of questions must first be answered: What aspect or dimension of the risk is aimed at by the control campaign? Who does it target (target groups or all the public)? How is it intended to achieve the objective of better efficiency/acceptability?

7In summary, if communication is to be effective it must be conceived as a product derived from knowledge appertaining to a given risk situation, in a given context. Such knowledge concerns the perceptions of the public, both of the vector risk and the relative benefits/risks of vector control. It may be, for example, that people’s “beliefs” move in opposition to the proven scientific reality. During the chikungunya epidemic in2005-2006, for instance, a survey done in May 2006 revealed that nearly 25% of the population doubted the assertion that the mosquito was the only cause (for references, see CD-ROM).

DIFFERENT TYPES OF VECTOR CONTROL AND ASSOCIATED PERCEPTIONS

8There is no single perception of vector control but many different ones attached to each of the methods of action and to which are added other differentiating factors like cost, perceived danger and various constraints (such as environmental, living conditions, level of development).

9The approaches or techniques of vector control are, in concrete terms, divided along three main lines:

  • environmental prophylactic measures: the approach consists of eliminating the breeding grounds and all physical factors that encourage their presence and proliferation;
  • mechanical chemical control: this aims to destroy the mosquito (in aquatic and aerial stages) using chemical tools (insecticides) or biological ones (with bacteria, predators and so on);
  • personal protection: mosquito-repellent body creams or other physical means (mosquito nets, air conditioning) or chemical methods (such as room scenters, fly strips).

10Each of these techniques, set in operation by different actors, is covered in information, education, awareness-raising and mobilization actions, and also in health education, and by means of communication programmes. This great diversity of tools and actors means that vector control seems largely influenced by the distribution of responsibilities for their implementation (collective and/or individual, institutional or social, local or national)

11Individuals in fact choose one or more of the methods available, most often following a subjective assessment of the cost/desired benefits balance, thinking that they are then protected against mosquito bites. Concerning the subjective evaluation of the benefit/risk balance, an abundant literature sheds light on the inverse relationship between judgment of risk and judgment of the benefits of an item of technology, a medicine, for instance (see CD-ROM). One of the objectives of communication on vector control is precisely to make the benefits more clearly visible, involving: the complementary nature of the three lines of control, the respective specificities, efficiency as a function of the contexts and the risks run by misuses of each.

Eight questions as a perquisite for a successful communication campaign
■ How is vector control perceived in a situation of vector risk? If there is no proven vector risk, how is the communication action perceived?
■ What is the perception of vector risk and of the risks from vector control? And of the different means used? What are the risk trade-offs?
■ What relations are there between the perception of vector risk and communication about vector control?
■ What are the most promising actions in the field?
■ Community participation/mobilization: what are the hopes and practices?
■ What is known about communication on vector risk and its impacts?
■ Public communication and media communication: complementary or discordant?
■ What are the proposals for improving communication on risk in relation to vector control?

12Conclusion: it is neither appropriate to separate arbitrarily the perceptions of vector risk from the different perceptions of vector control, nor to isolate communication programmes from vector control. Naturally, here it is a matter of arriving at the conditions necessary for obtaining the desired changes in behaviour, but these conditions are not always sufficient.

CASE HISTORIES

13In the following examples, a partial response is made to some of the vital pre-campaign questions to be raised (see Box). For other questions, more research is needed. These presentations are based on the literature and on recent surveys (for further information on each example, see CD-ROM).

Martinique

14Perception of the effectiveness of the different protective methods (on a scale from 0 to 10) varies in considerable proportions, as shown in Figure 1, which results from a survey published in 2008. In particular, the people answering appear to endorse environmental protection methods. Indeed, such techniques probably have considerable influence on the presence of the disease vector in their habitat. However, at the same time they do not depend on them (at least not completely): most prophylactic measures proposed are implemented by the public services. The surveys therefore bring the weight of the responsibility for prevention – not on their own actions but on those of the local authority (mosquito destruction services), at least to a certain extent.

Figure 1. Perceived effectiveness of different protective measures

Figure 2. Why are you not satisfied with mosquito destruction?

15On the whole, most of the respondents appeared satisfied with the mosquito destruction services (about 2/3 of them). But what were the reasons for the dissatisfaction of the other third of them? The questionnaire included an open question for their intention. As Figure 2 testifies, a large majority criticised mosquito destruction (insufficient frequency or incomprehension of the rules for distribution). A small minority thought it to be useless and/or toxic for the environment. That could be interpreted as a minimization of the mosquito cause.

Reunion Island

16A survey report published in 2006 shows that, of the three types of collective measures – vector control by people from metropolitan France/vector control by local people/waste disposal, disposal of bulky waste and scrap cars – the third was perceived as the most effective.

17As for their perception of danger of insecticides for humans, the fauna and flora, which is noted on a scale from 0 (not dangerous) to 10 (very dangerous), they find that the risk is highest for animal and human health, and slightly higher for animals (probably stemming from media coverage of many cases of poisoning of domestic or farm animals during the survey period).

18Certain human diseases are seen as being associated with insecticides. These include respiratory diseases and skin complaints considered as benign (such as asthma, allergies, dermatosis), serious illnesses such as cancer for only a minority of respondents (23%). However, in general chikungunya seems to cause much more concern than diseases potentially linked to the use of insecticides to control it.

Mayotte

19A survey run at the end of 2007 recorded 94.6 % of positive replies to the question as to whether or not it is useful to employ insecticides. The comparative study of perceptions to different protection measures showed a clear preference for mosquito nets rather than chemical products (diffusers, repellents and so on), as Figure 3 shows.

Figure 3. Perception of effectiveness of six protection measures

In the absence of vector risk

20A certain number of studies conducted in metropolitan France have shown that, when there is no vector risk, the question of mosquitoes and mosquito destruction is a subject that arouses contradictory arguments among the actors involved. This reveals a complex, changing social reality. The conclusions of these studies showed that while the people questioned admitted to be troubled by mosquitoes they were used to them, that the mosquito was certainly a nuisance, but also useful for nature. They were rather in favour of mosquito destruction but wished to preserve “natural” areas. The authors concluded, underlining this indecisive attitude among a fair majority of respondents, that this opinion “is an indication in individuals of a coexistence between anthropocentric and biocentric references”.

21The actions taken and the information and communication concerning them are most often conducted in close cooperation between the EID services and the municipal hygiene and health departments of the large towns and cities: see, for example, the Web sites of Lyon, Cannes, Bourg-en-Bresse. These sites generally inform about the implementation of nuisance organism control, pointing out that the animals in question (insects, rodents) can carry diseases and that this control effort is made as part of a “cleanliness and public health” approach.

In the literature

22Some studies deal with the role of the media, on the shaping of individuals’ judgment in the face of unknown risk like that which is linked to pesticides, or on the impact of communication campaigns (for further information, with references, see CD-ROM).

23Concerning the media, an American study (2002) focused on their role in the construction of the perception of risk of insecticides in control of West Nile virus (WNV). The result: there was insufficient information on the risks linked to pesticides and on the risks of exposure to pesticides vs those linked to WNV. The same observation was made for information on the effectiveness of spraying and their cost vs that of WNV encephalitis. The control effort against WNV is a perfect illustration of the risk trade-off and only a comparative assessment could enable the public to judge the pertinence of this anti-vector campaign.

24The development of the judgment individuals have about an unknown risk (that is, a new one) is the subject of another study which showed that the subjective assessment of an unknown risk (in this case, risk associated with pesticides) is built up from the association with other risks (known ones): one talks of associated risks. Hence the suggestion to base communication on “mental models”.

25As for the impact of communication campaigns, a study focusing on the control of proliferation of Aedes aegypti breeding-sites brings out a paradox: the impact on breeding sites of an educational communication action would be more effective than that of malathion spraying, even when the two methods are combined. The interpretation: the association of insecticide spraying would generate a (false) sense of protection.

COMMUNICATION: ABOUT WHAT AND HOW?

26Little or no research deals with communication on vector control. However, publications do exist that concern communication about the risk of infectious diseases or on vector risk, which have the same base.

27A British study (2000) demonstrated to what extent the impact of communication (on the perception of risk in general) depends on complex interactions between the audience characteristics, the source of the messages and its content. The content should therefore have the following attributes:

  • capable of hooking the attention;
  • comprehensible;
  • aim to influence the decision;
  • free of ambiguities;
  • easy to interpret in order to influence the decision of the target.

28Confidence also plays an important role in that it is associated with the expertise of the source, with its unbiased character and not aiming for the sensational effect.

29Conclusion: the qualities necessary for maximizing the impact of the communication are often difficult to bring together owing to the scientific uncertainty.

30The case of SARS, like those of chikungunya and dengue, shows in particular that the public tends to determine its behaviour from its perception of the risk (and not on the real risk) in the context of strong uncertainties regarding the transmission routes of the infection, on its gravity, the treatments available and on the ability for individual control. Individuals often base their decisions on the behaviour of others, especially if the information that reaches them results from opinions rather than science.

31An American study (2006) has shown, for example, that Canadian media circulated information that was often contradictory (for example, that SARS is a dangerous threat but a distant one) or confused. Improvement to communication will be made possible by a fine knowledge of the public’s perceptions, but also other governmental actors: how do individuals assess their own exposure to risk? In what way do perceptions affect behaviour? What effects do the different strategies implemented have on perceptions?

FIELD CAMPAIGNS

32A host of actions have been undertaken in the field, notably at the time of the chikungunya epidemic in Reunion Island (see Box, and for more details or other examples, see CD-ROM)

Networks of information, education and communication on vector control
Following on from the Combi workshop held by WHO in Reunion from 19 to 28 June 2006, the Regional Health and Social Affairs Service (DRASS) devised a Social Mobilization Plan, from September 20006, hinged on five major lines of action: institutional mobilization, community mobilization, public information campaigns, inter-personal communication and promotion of information points. The objectives pursued concern the adoption of three individual behaviours, complementary to the vector control, the epidemiological watch and the offer of health care:
– daily inspection by every household of the immediate vicinity of their home in order to eliminate all potential breeding sites;
– self-declaration by telephone, using a special Green Number, by all persons showing symptoms similar to chikungunya or dengue;
– use of individual protective measures (repellents, long clothes, mosquito nets) including, if infection occurs, in a period of viraemia.
Below is a summary of some strengths and weaknesses of this system:
Follow-up and coordination of the networks
– The large scale of the chikungunya epidemic prompted the federation of the associations and institutions operating in health education around health messages concerning vector control. The network nevertheless needs to have a stronger structure and activated for inter-epidemic periods.
– The training courses for relay-instructors have not always produced the results expected.
– The chikungunya crisis brought out the importance of the media in the circulation and delivery of messages, and therefore in people’s degree of acceptance of vector control measures.
Assessment of awareness-raising actions
– To date there are hardly any assessment tools for measuring any “growth” in knowledge or change in behaviour.
Competence of the actors of social mobilization
– Health education cannot rely on amateurism: sessions for continuous training should be set up to consolidate the base for the different messages to be delivered, but also to ensure knowledge is updated.
– The ideal would be to devise a guide for health education on vector control. The National Institute for Prevention and Education for Health (INPES) could be called upon.
Improvement of health education messages
– Vector control messages, especially after the chikungunya crisis, are sometimes perceived negatively.
– In the field, the messages are well integrated, but they are not applied. Understanding of the message does not imply implementation. What is the solution?

Community participation
The WHO, strongly attached to community-based effort for vector control, has drawn up a social mobilization plan encouraging actions that take into account the public’s perceptions and wishes. At present, there are few works that allow impacts to be assessed. However, two studies are worth mentioning: one concerning the assessment of a programme in Porto Rico (2002), the other that of a programme run in Cuba (2004). The first showed a significant increase in knowledge and awareness among the public, but only a small number of changes to behaviour and limited changes in the larval indices. The second (2004) noted some results regarding perception and judgments on the value of community participation: the respondents recognize the utility and the obligation to take part (for social and political conformity?), but they severely criticise their leaders, judged to be more preoccupied by their own well-being than by problems of the community.
A number of criticisms also come out from other publications. For example, expectations would not be translated into the desired effects owing to the weight of the old paradigm (magic bullet). Hence the idea for a new paradigm, founded on a process of iterative learning. Another explanation that has been put forward: the ideological and political opposition between the pragmatists, in favour of utilitarian models of participation, and activists who promote the empowerment model. Finally, a recent article (2007) produced a meta-analysis of assessments published concerning community participation (11 studies selected). Its conclusion: evidence in favour of the effectiveness of a community approach, on its own or combined with other measures, is weak (see “Practices and methods”, chapter 3.
Concerning educational communication, some people call for the development of the “science-based communication and assessment for policy making toward sustainable health and ecosystem” by way of the setting-up of Centres of excellence for research and training in ecology and health. As for the question of generalist vs targeted communication, the reply comes out of the identification of the most exposed or the most vulnerable social groups: there would not be much sense in promoting solely generalist (undifferentiated) campaigns if one opted for the paradigm of basing communication on the knowledge of the perceptions and their distribution.

33Among the campaigns organized, must be mentioned the annual Kass Moustik Day, the result of the work of a collective of associations, personalities and institutions working to further public participation. This special day is designed to be a high point of education and community mobilization around the destruction of breeding sites. It is considered to be a success by the local parties involved. It takes place on the eve of the Day of the Dead and participates in the same spirit that activates the Toussaint (All Saints) operation in Martinique. However, assessment of this (on the basis of the Breteau index) shows at once a noticeable effect and a return to the previous situation after a number of weeks.

34Moreover, a report on the problem of dengue in the DFAs, produced by the IRD in 2003, emphasizes the necessity now to call upon community participation (see Box). This same report identified some actions considered to be only weakly conclusive: household visits of agents of mosquito destruction services, public information meetings and particularly the pilot mobilization project for municipal managers of the town of Schoelcher, qualified as a failure. Conversely, the presence of information stands in public places or coinciding with events (like the Toussaint operation) and educational campaigns for schools have been shown to be effective;

35More generally, it appears more and more essential to associate all the actors involved, set up networks, encourage transverse efforts, develop training and take informal structures into account. When partnerships are established, the classifications must also be rethought. Rather than being based on the categories individual/associative/institutional, it would be preferable to think in terms of strategic issues: partners based on proximity, interest, or opinion. The latter category is becoming inevitable, “in that the mosquito destruction services will be obliged to move up to another scale in terms of communication” (source: expert report 2003).

RECOMMENDATIONS
General proposals for structural improvement
– Base vector-control communication programmes on the identification of perceptions, beliefs and practices using data form representative surveys among populations exposed to vector risk, taking into account confirmed existing knowledge.
– Organize vector-control communication to allow better monitoring of the utility/efficacy of the different methods and tools used according to the level of vector risk.
– Decide on the content of the communication programme according to the socio-cultural and epidemiological contexts and the vectors present, so that social groups can be targeted in line with the risk factors and people’s vulnerability and possible reservations about adopting protective behaviours.
– Develop interdisciplinary research using a social science basis as the core approach, in particular when studying populations exposed to mosquito bites where there is no vector risk of infectious diseases.
– Assess programmes of health communication and education according to their effect in prompting lasting change in perceptions and behaviour, not only in terms of memorizing information or knowledge gained.
– Assess programmes for developing community participation in vector control, using entomological and epidemiological indicators, and identify any obstacles to their efficacy or durability.
– In the case of the vector Aedes albopictus: the above recommendations are especially relevant to this mosquito. There is a risk in the coming years of colonization in French metropolitan departments like Hérault or Bouches-du-Rhône. Beyond purely technical aspects, communication messages and campaignsto prepare the public, political representatives and public health services for this likely colonization, or even a chikungunya or dengue epidemic, in France can be launched only on the basis of prior studies undertaken in the exposed population.
Operational proposals
– Establish a central platform (INPES) for developing a set of methods and an approach to communication and health education concerning vector control. This will allow work on the content of model messages, assessment of the best communication vehicles, contribution to be made to training of instructors and provide continuous training for agents working in these areas.
– Set up a social mobilization team attached to the governance structures proposed in this report (GIP/ARS) to achieve better coordination with technical aspects and initiatives engaged in by the associations, to assist with their realization and expansion (finance, message contents and so on).
– Organize regular communication with the media in order to reduce the elements of discord, where possible, by providing real-time information, especially when warnings have been raised or at times of epidemic outbreaks.
– Develop a strategic communication plan that can be used in case of an epidemic, and quickly put into practice to fit the situations created as the outbreak progresses.

Notes

1 In this chapter, references to the CD-ROM concern question 6: “Perceptions and information-education-communication (IEC) on vector control: current state of the issue, problems raised and proposals”.

Table des illustrations

Légende Figure 1. Perceived effectiveness of different protective measures
URL http://books.openedition.org/irdeditions/docannexe/image/1271/img-1.jpg
Fichier image/jpeg, 99k
Légende Figure 2. Why are you not satisfied with mosquito destruction?
URL http://books.openedition.org/irdeditions/docannexe/image/1271/img-2.jpg
Fichier image/jpeg, 61k
Légende Figure 3. Perception of effectiveness of six protection measures
URL http://books.openedition.org/irdeditions/docannexe/image/1271/img-3.jpg
Fichier image/jpeg, 88k

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