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La lutte antivectorielle en France

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

Implementation of vector control

Strategy variations between regions1

Texte intégral

  • 1 In this chapter, references to the CD-ROM concern question 4: “What are the vector control strateg (...)

1Vector control makes use of different tools and techniques depending on the objectives and the group of vectors targeted. It can aim at reducing vector populations to below the thresholds required for transmission (see the chapter “From vector risk assessment to epidemic risk assessment”), or at the avoidance of host/vector contact, or again eradication of populations of a given geographical area. Control methods therefore also differ, depending on the objectives fixed and the vector, ecosystem and environmental context, but also the economic and sociopolitical situation. Generically, five large categories of means can be applied: environmental control, biological control, genetic, mechanical and chemical (see all the control methods in detail on the CD-ROM, also Chapters “Legislative and regulatory framework for vector control”. “Research: a key to successful vector control” and “Unwanted side-effects of vector control”).

2The first category groups together the actions conducted in the environment to make it hostile for the development of vector populations. The second consists of using a “natural enemy” of the target vector to reduce the number and thus the risks of transmission of the pathogen (virus, bacterium, rickettsia, fungus, parasite). Genetic control aims especially at lowering the reproductive potential of harmful arthropods by altering or replacing some of their hereditary potential. The term mechanical control embraces the techniques devoted to catching the vectors and those which hinder contact between host and vector. Finally, chemical control draws on the use of chemical products (of plant origin or synthetic) to make insecticides, repellents or bait for insect vectors.

3This chapter reports on the different strategies adopted both in French overseas territories and metropolitan France.

HUMAN HEALTH

4At present, vector-borne transmissible diseases mainly concern the overseas territories. However, they do not spare metropolitan France, particularly Corsica and the mainland part of the Mediterranean rim.

In the overseas territories

5Vector watch and/or early warning plans of varying scope have been put in place.

Guadeloupe

6The only currently important disease is dengue. It is transmitted by the vector Aedes aegypti and has been raging for some years in an endo-epidemic mode. This vector reproduces mainly in small reserves of clear water, in or around housing: water storage butts (30 % of larval development grounds listed), flower vases (10 % of breeding grounds), tanks, gutters, a range of objects and waste that could hold rainwater, and so on.

7Taking account of the ecology of the vector, the basic strategy consists of making household visits during which vector control agents destroy the breeding grounds for Aedes aegypti or treat them chemically. In parallel, these agents contribute to the health education of the people visited. And actions of social mobilization are developed with the municipalities (community-based health projects), as are awareness-raising campaigns in schools or, more occasionally, among associations.

8On the technical front, the actors involved in vector control endeavour to establish permanently running, but non chemical, schemes on: lids for water butts, gutter alterations, elimination of old worn tyres. Entomological surveillance also focuses on Aedes albopictus (ports, airports) and on the nuisance species such as Culex quinquefasciatus. More globally, municipal plans are being devised.

9A dengue PSAGE was drawn up in 2006 in the framework of a partnership between the CIRE-AG, the Martinique mosquito destruction service, the Health Watch Units of Martinique and Guadeloupe, and the Guadeloupe vector control service (see “How is governance organized?”, part 1). A similar scheme is under way for the French departments of America in the context of chikungunya control.

10One of the new features is the growing use of geographical information systems (GIS). One of the major difficulties: other than the social tensions stemming from transfer of personnel to the département council, middle management numbers are insufficient. It cannot be normal that the entire management of a vector control service such as that of Guadeloupe should fall to one part-time person (the entomology officer of this service operates for only 70 % of his time in an area greater than Martinique, which is provided with two entomologists and a technical officer working full-time).

French Guiana

11There is a monitoring committee on insect-borne human disease, composed of a range of health and vector-control bodies working over the territory: the Department of Health and Social Development (DSDS), the Departmental Mosquito Eradication Service (SDD), the French Guiana Pasteur Institute (IPG), hospitals, university, independent medical practitioners. This committee regularly reviews the epidemiological situation of the different vector-borne diseases (mainly malaria and dengue) and decides on possible improvements to procedures for controlling these diseases.

12Dengue, chikungunya and yellow fever are some of these diseases placed under high surveillance. For yellow fever, the last case recorded dates back to 1998. The principal prevention method is vaccination. As for vector control, it can be made part of measures against Aedes aegypti, potential vector of this disease in urban areas, as well as its ability to transmit dengue. The entomological watch system for the latter consists in assessing the monthly Breteau indices (BI), by sampling over all the sectors of municipalities of Cayenne Island, and assessing them on systematic household visits in the other municipal areas. True vector control entails several stages depending on the epidemic situation and location:

  • systematic household visits, possibly oriented by BI indices, with mechanical destruction of breeding sites and Bti treatment of such sites that are impossible to destroy physically;
  • insecticide spraying using tractor-drawn machinery [Ultralow Volume (ULV)] in all areas accessible by car according to a pre-established programme;
  • actions conducted around cases reported by the DSDS with exact addresses: at the patient’s home, deltamethrin spraying inside the home and mechanical elimination of breeding places, even larvacide treatment using Bti if necessary; around cases in urbanized areas like Cayenne, mechanical elimination of breeding sites, or even if necessary larvacide treatment and spatial spraying with insecticide in the housing block where the case arose; on cases in a residential area (with villas), operation in a 100 metre radius (mechanical elimination of breeding sites and, where necessary, larvacide treatment and spatial spraying with insecticide outside the houses);
  • actions where the address is unknown or uncertain: spatial spraying with insecticide over the whole residential block or estate or of the supposed site of case(s) at the rate of one passage per week (two weeks in succession).

13Malaria is a serious public health problem in French Guiana, where it rages along the border rivers (with Surinam on the west and Brazil to the east), it is transmitted mainly by Aedes darlingi but also by several secondary vectors. A map of risk zones, regularly updated by the monitoring commit-tee, is available on the web site of the French Guiana prefecture. Vector control is essentially based on wall spraying with insecticides (deltamethrin) every three to four months in the endemic areas, an operation carried out by the SDD. Also noteworthy are occasional interventions around recorded cases. Operations promoting long-term impregnated mosquito nets have also been launched, in 2008, with the participation of the Mother and Infant Protection services of the Red Cross, SDD and so on. The major breeding areas (swampy land, canals and so on) are treated with temephos. In parallel a certain number of recommendations are made available for non-residents.

14However, no specific vector control is currently applied for West Nile fever (surveillance effort essentially entails checking and monitoring equine health by veterinary services), nor for leishmaniasis (except for advice given to people intending to venture into the forest), nor for Chagas disease. The latter disease is nevertheless the subject of a research programme under the leadership of the laboratory of parasitology of the Cayenne CHU hospital. Added to these activities, actions are conducted against nuisance organisms (see CD-ROM).

Martinique

15Since 1991, following an agreement for pooling State and département council human resources and materials, the activities of the vector control are practised as part of a generalized mosquito destruction drive (against both disease vectors and nuisance types). The strategy implemented focuses on:

  • information campaign aimed at all sections of the public;
  • cleansing of surrounding areas (at individual and collective level);
  • development of a community-based approach: intervention of municipal-mosquito eradication relays, ‘Toussaint operation’ (since 1998), educational tools in partnership with the French National education ministry, Anti-Mosquito Day, mosquito destruction workshops;
  • rational use of insecticide substances (chemical and biological).

16In parallel, research geared to operational aspects has developed over more than 15 years (ecology of Aedes aegypti, resistance to insecticides, entomological indicators and so on).

17The vector control actions mainly focus on dengue, malaria and West Nile fever. For dengue, interventions since 2006 have been formalized in the context of the PSAGE already mentioned. For malaria, the imported cases are reported to the SDD which then performs entomo-epidemiological investigations and then possibly sets up vector control action against anophelines (Anopheles albimanus in particular). As for West Nile virus, an action was launched in 2003 with the veterinary services even though no case (either human or animal) had been recorded. Mapping of equine or ovine rearing sites is kept updated, as these establishments are kept under entomological surveillance (systematic eradication/treatment of identified breeding sites). An entomological watch on Aedes albopictus is also kept. This involves a surveillance network set up in 1987 and reinforced in 2004 for certain particularly sensitive sites (port and airport areas, marinas and so on). Nuisance species are also covered by regular control procedures (see CD-ROM).

Reunion Island

18Malaria has been eradicated from the island (malaria eradication label awarded by WHO in 1979). Yet Reunion island is still a vulnerable area owing to the presence of the vector Anopheles arabiensis (particularly on the coastal zones) and the intensification of travel and trade with neighbouring countries. The current control strategy aims to prevent the reintroduction and settling of the parasite and to be well prepared to intervene against any cases declared. Practically all cases (between 100 and 150 per year) are imported (48 % from the Comoro Islands, 41 % from Madagascar). The main breeding sites are mapped, making it possible to trace their locations and hence decide which preventive treatments to employ. The objective is to keep the vector restricted to rural areas, where treatment campaigns have been pursued since the 1980s.

19Concerning dengue, yellow fever, chikungunya and Rift Valley Fever (RVF), control efforts rather “benefited” from the resurgence of dengue (2004). The vector control service has started to develop a control strategy against urban vectors and especially targeting Aedes albopictus. The first actions (perifocal control, health education) were complemented in the light of experience acquired during the chikungunya epidemic (2005-2006). The omnipresence of Aedes albopictus in all the urban areas, up to 1,200 m altitude and throughout the year on the coast, obliges the vector control service to focus its control campaigns on that.

20The island’s 28 municipalities are further divided into 1,093 “homogeneous” areas (see details on CD-ROM) grouped into 274 urban districts. Each month, 150 to 200 assessments are conducted on these zones, which allows targeting on those with the highest vector densities. In parallel, actions are performed to reduce the aquatic stages of the vector by acting on the main productive breeding sites whether permanent (cemeteries, ravines, natural basins and so on) or temporary (like waste disposal sites, carcasses, building sites).

21Another portion of the adopted strategy is the treatment of cases of arbovirus infections, to prevent transmission of the virus and the appearance of secondary cases. A health watch unit has thus been set in place at the DASS since December 2006, complementary to the surveillance system based on the data collected by the hospitals and analytical laboratories. A community-based approach developed at the same time. It aims to inform the public of measures that can be applied based on the Combi method (see the chapter “Perceptions of risk in relation to vector control communication”, and on CD-ROM). Further, all the actions of the vector control service are georeferenced, recorded and kept in a database and analysed every week.

22A public interest group “Reinforced Prophylaxis Service” (RPS) was set up in October 2006 (see chapter “How is governance organized?”), to coordinate public policies. It associates the State and the territorial and local authorities. The actions conducted in the framework of this public interest group enjoy better public visibility and their effectiveness is greatly enhanced by the pooling of human and material resources. This coexistence at the heart of the same reference-structure therefore gives a great advantage and will be of prime importance if the island had to cope with another major epidemic.

Mayotte

23This island is an endemic area for malaria. The annual rate of malaria incidence amounts to between 3.1 and 5 ‰, and shows a fall in the number of cases reported over the past five years (792 cases in 2003, 496 cases in 2006). Imported malaria comes mainly from the Comoro Islands.

24The control strategy against plasmodium vectors (Anopheles gambiae and Anopheles funestus) largely relies on chemical imagocide (against adults) and larvacide methods. Residual-effect treatments are applied inside homes every four to five months, with quite a good coverage rate (about 80 %). Organophosphate antilarval treatments are regularly applied in puddles and temporary ruts, stagnant water and so on. The large permanent ponds an hill reservoirs are also treated (seeding with larvivore fish). Entomological surveys are conducted around every declared malaria case, with destruction of possible breeding sites and possible treatment in nearby housing. It must be noted, moreover, that the malaria control strategy in Mayotte will only be fully effective if malaria control effort is also intensified at regional level (notably in the islands of the Comoros archipelago).

25Control of arboviruses and their vectors has been developed only recently, for the same reasons as in Reunion Island. Since the 2005-2006 chikungunya epidemic, the vector control service has been conducting a drive for urban vector control, particularly Aedes aegypti and Aedes albopictus. From the southern summer of 2006 a widespread campaign of chemical treatment (using imagocide and larvacide around housing) was organized municipality by municipality, which made extra personnel necessary, nearly 150 temporary agents. The community-based approach was also strengthened by setting up a social mobilization and health education programme using the Combi method (see the chapter “Perception of risk in relation to vector control communication” and on the CD-ROM).

26Recently, a dozen human cases of Rift Valley fever were identified, and also some in livestock (cattle and small ruminant). This new risk led to the development of targeted control operations, including entomological surveys and mosquito capture (around the cases found and the affected livestock) and preventive treatments to limit the expansion of the virus. The arbovirus vector control strategy is soon to be revised to integrate the perifocal control around reported cases and develop entomological surveillance to help find the appropriate orientation of control actions. A health watch unit is also being set up.

Metropolitan France

27The areas around the Mediterranean, in Corsica and on the mainland are the most exposed to risks. As in overseas territories, control strategies are laid down in the regulatory and legislative framework, determined in particular by laws 64-1246 of December 1964 and August 2004 and also by a number of circulars (see the chapter “Legislative and regulatory framework for vector control”).

Corsica

28Vector control in Corsica is mainly turned towards nuisance mosquitoes: Culex sp., Aedes (Ochlerotatus) caspius, Aedes detritus, Aedes vexans and Aedes mariae. It also targets certain potential arbovirus (Aedes albopictus) or Plasmodium vectors (Anopheles of the Maculipennis complex including Anopheles labranchiae). The first report of vector Aedes albopictus in Corsica was made in 2006. And the last malaria epidemic dates back to 1972. Five organizations are currently involved in nuisance or vector control operations: the département councils of Corse-du-Sud and Haute-Corse, the Corsica and Corse-du-Sud Departments of Social Security and Health (DSS), the Departmental health and Social Affairs Service (DDASS) of Haute-Corse and Bastia Muncipal Hygiene and Health Service (SCHS).

29The control actions conducted in Haute-Corse more precisely fall within the framework of surveillance and control of vectors of Plasmodium (identification and treatment of breeding grounds) and Aedes albopictus (antilarval and imagocide treatments). In Haute-Corse, nearly 1,400 Anopheles breeding sites are monitored and treated (using anti-larval treatments predominantly). Since the appearance of Aedes albopictus, the vector control service’s activity has diversified. The nuisance mosquitoes are now under control schemes. In both Haute-Corse and Corse-du-Sud, the actors involved in vector control have taken note of the recent installation of this vector and are working to devise their strategy.

Mainland areas

30In both urban and rural environments, the strategic priorities focus on breeding site control. An advantage of this is the possibility of identifying the species to target and the extent of the areas to be treated and, by the same token, make better choice of insecticides while reducing their environmental impacts. In essence, this control effort aims at three species of mosquito (out of 105 present in France) reputed for causing the greatest nuisance: Aedes (Ochlerotatus) caspius and Aedes (Ochlerotatus) detritus, also Culex pipiens molestus (a commensal species with humans that occurs in urban environments). A little more than 15 others (see CD-ROM), causing differing degrees of nuisance, locally or seasonally, are the focus of specific control measures conducted by the Interdepartmental Mosquito Eradication task forces (EIDs), whereas Aedes albopictus has been under surveillance since only recently, notably as part of the chikungunya and dengue antiproliferation plan for metropolitan France.

31The antilarval strategy is based on a multi-stage process. The first consists in mapping the larval biotopes and potential hatching areas. This is done at a very small scale using methods and typology defined by the EID for the Mediterranean. It is regularly updated with GIS georeferenced data and is an aid for surveying and for delimiting the exact treatment areas. In a natural environment, the sites are identified and recorded using environment-mosquito-vegetation correlations established by the operator for wetlands in his radius of action (see CD-ROM). This map helps the operator understand the functioning of the natural areas where he is going to intervene. It is a useful tool for training, diagnosis, management and communication for an integrated control effort. In urban areas, the permanent and/or potentially highly productive breeding sites (even occasional ones) in public or private grounds are systematically recorded which can help draw specific maps.

The three main nuisance mosquitio species in the Mediterranean
Aedes (Ochlerotatus) caspius and Aedes (Ochlerotatus) detritus are halophile species enfeoffed in natural semi-temporary brackish wetlands and particularly well adapted to the Mediterranean climate. Hatching is triggered by submergence yet the eggs remain viable for several years without water cover. The nuisance comes on abruptly, especially at dawn and dusk, away from housing. The water management of natural habitats therefore plays a vital role. For example, irrigation of saltings and temporary marshes are highly favourable for hatching.
As for Culex pipiens molestus, it colonizes domestic stagnant waters and wastewater. It bites at night in close proximity to breeding sites, mainly inside housing. This species, present in all urban agglomerations, is the cause of local nuisance effects.
For further information: see CD-ROM.

32The second stage hinges on observation of water-level variations and identification of hatchings. Its purpose is to detect the areas to be treated and demarcation of exact treatment areas, using the occurrence of water advances observed on larval habitats, with the aid of the map work produced in the first stage. The basic idea is to apply the treatments as far upstream in the process as possible, for maximum effectiveness. Potential biotopes of each wetland area or urban sector are therefore repeatedly studied by field observations, at variable frequencies depending on the species concerned, weather conditions and human water management operations (see CD-ROM). This stage (more than 60 % of agents’ time) ensures the accuracy of subsequent treatments, especially targeted mosquito destruction that limits environmental impact.

33There follows the stage of choice of operation type (physical, chemical etc., terrestrial or aerial). This choice is made following a set of parameters: occurrence or not of water advance onto larval habitats, development stage of larvae and density, probabilities of hatching, meteorological situation and distance between breeding sites and the areas to be protected. Account must also be taken of the availability of equipment and materials, but also of the public’s sensitivity to risks for the environment. Other methods, but working over a longer term, can in the end be employed, such as maintenance, prevention work, water management or rehabilitation (dune banks in marshy terrains for instance).

34The actual treatment operations depend largely on the surface areas to be treated. Small areas can be dealt with by using various terrestrial techniques. More extensive surfaces (50 to 1,000 ha/day) require airborne treatment. The Mediterranean EID, for example, has been equipped with a supply station (Candillargues aerodrome, Herault) and a fleet of six aircraft since 2007. The choice of biocides is regulated by the biocide scheme/system (directive 98/8 EC) (see CD-ROM and chapters “Legislative and regulatory framework for vector control”, and “Research: a key to successful vector control”). Bti is the only larvacide in use and it is usually sufficiently effective. As for imagocides, or adulticides, fenitrothion is used (before its final withdrawal from the market at the end of 2009) in natural areas. In urban centres or peripheries, deltamethrin is employed either on its own or associated with esbiothrin.

35The efficacy of treatments must also necessarily be checked after application. Such assessment is carried out by new surveys and capture of adults.

36These investigations can lead to a repeat larvacide treatment or to application of adulticide in some cases. The emergence of adults on certain sites, even if small in surface area, can considerably reduce the overall success rate of the mosquito destruction system, in particular near urbanized zones;

ANIMAL HEALTH

37Tick-borne diseases in the French Departments of America (FDAs), blood parasite diseases (haemoparasitoses) in bovines on Reunion Island, bluetongue virus in sheep in metropolitan France: these are just some of the diseases that can hit animals.

In the French Departments of America

38The tick Amblyomma variegatum transmits cowdriosis, or heartwater disease, to a high proportion of cattle in Guadeloupe, Marie-Galante and Antigua, whereas Martinique is unaffected. The babesioses and anaplasmoses, spread by Boophilus microplus, however, affect livestock in all three of these départements. Several serotypes of bluetongue virus are also present, although there are currently practically no clinical effects. In French Guiana a high level of trypanosomiasis caused by Trypanosoma vivax borne mechanically by stomoxes and tabanids is present.

39There is no organized vector control system in French Guiana. Moreover, the veterinary services which provided free care services for livestock keepers shut down in 2007. Also, the absence of a legal base for border control measures means that such procedures are limited to awareness building among stockmen by the Departmental Veterinary Service (DDSV) to dissuade them from importing animals from infected areas.

40For the departments of Guadeloupe and Martinique, the State has launched a Specific Operation Programme for distance and isolation of the overseas departments (POSEIDOM) to control tick-borne diseases. From 2000, the planned strategy was to move towards a bimonthly epidermal treatment of livestock by teams from the Health Defence Groups (GDS), first with amitraz (an acaricide), then flumethrin (pyrethrinoid). This treatment is not free (unlike the option adopted by the similar programme in the Caribbean, the Caribbean Amblyomma Program (CAP) (see CD-ROM).

41However, it is strongly subsidized by the Ministry of Agriculture and Fisheries and by European funds. Prefectoral orders make these measures compulsory. In Martinique, the livestock is classified according to their status regarding the presence of Amblyomma variegatum.

42Nevertheless, since 2003 political problems within the Health Defence Group in Guadeloupe have held back control operations. Finally, although the strategy determined has proved to be effective for control of tick-borne diseases (eradication of Amblyomma variegatum from some Caribbean islands as part of the CAP), its implementation comes up against the extreme intensity of infestation in certain areas (Guadeloupe), the type of husbandry (family-based rearing, tethered cattle system) and the organizational problems of the GDSs (Guadeloupe).

Reunion Island

43Other than haemoparasitoses (fourth cause of animal deaths in 2004), the diseases affecting animals are: babesiosis (Babesia bigemina and Babesia bovis borne by Boophilus microplus), anaplasmosis (Anaplasma marginale transmitted by Boophilus microplus or by stomoxes Stomoxys calcitrans and Stomoxys niger), cowdriosis (Cowdria ruminantium borne by Amblyomma variegatum). Transmission also occurs of several serotypes of bluetongue, although no clinical repercussions have been recorded to date.

44The POSEIDOM programme was implemented by the Regional Group for Livestock Health Defence (GRDSBR). At the start, it consisted of free distribution of deltamethrin in the form of a ‘pour-on’ by veterinary clinics. From 1996, however, control treatments offered were diversified: combination of biological, mechanical, chemical and environmental methods against the Boophilus ticks and chemical treatment alone against Amblyomma ticks. From 2002 a engagement contract was signed with stock breeders who decided to join the programme, with possibilities for technical and financial aid offered.

45An assessment was made by following up autopsy results by a network of epidemiological surveillance and serological assays (data available for Babesia bigemina and Anaplasma marginale). It was found that seroprevalence between 1994 and 2006 had fallen only slightly for babesiosis and that it had risen for anaplasmosis, with strong interannual variations. This relative failure could be explained by too small a reduction in numbers to break the transmission cycles. Vector control in this département has suffered from an insufficiency of entomological research on the biology of vectors before the control effort was launched.

Metropolitan France

46The main vector-borne disease is bluetongue. Between 2000 and 2004, the only part of the territory concerned was Corsica (serotypes 2, 4, 16) after the presence of Culicoides imicola, the main vector of bluetongue virus in the Old World, was confirmed. The transmission of this virus in Corsica and the rest of the Mediterranean Basin is associated with the northward extension of the distribution range of Culicoides imicola, which could be linked to changes in Mediterranean ecosystems (for the migration of this vector, see CD-ROM and the chapter “From vector risk assessment to epidemic risk assessment”). In another ecological context, following the unexpected introduction of serotype 8 in the Benelux countries in 2006, a great majority of France was infected by this serotype at the end of 2008. Moreover, at the end of 2007, serotype 1 was introduced into the Spanish and French Basque country, to reach into the whole South-West quarter of France in 2008.

47Apart from bluetongue, other diseases affect livestock, like tick-borne diseases (such as piroplasmosis and besnoidiosis, in expansion in the Provence-Alpes-Côte d’Azur Region). Also to be pointed out is the first out-break of surra, (Trypanosoma evansi trypanosomiasis) on the European continent, detected in a herd of Aveyron dromedaries in October 2006. Finally, a case of high nuisance-level Simuliids (blackfly) was described in Hérault (in the Lodève area), with such effects as falls in milk production. In this respect, Mediterranean EID could not intervene for mainly regulatory reasons (need for a prefectoral order, after consultation of the Departmental Council on the Environment and Health and Technological Risks, CODERST).

48Vector control against bluetongue is regulated by European directive 2000/75, transposed into national law by Ministerial order of 24 August, itself replaced by that of 1 April 2008 (confinement of animals inside at times of day of vector activity, regular treatment of animals using insecticides). Furthermore, European regulation 1266/2007 defines the waivers for export authorization if the animals are “protected from attacks by the vector Culicoides” during their transport and for a certain number of days before being moved. France translates this rather vague anti-vector protection by treatment of the animals with epidermal insecticide (service note DGAL/SDSPA/N2007-8276).

49In Corsica, the product (pour-on solution of deltamethrin) is available free-of-charge by way of GDS branches. On the mainland no measures of this type have been put in place and insecticide buying is still the stock breeders’ responsibility. An enquiry conducted by the National Federation of GDS has shown that few stockbreeders in the North of France had treated their animals in 2007.

50The use of pyrethrinoid epidermal insecticides is based on the following observations: absence of detailed knowledge on species of Culicoides involved in transmission, absence of identification of breeding sites and the difficulty of treating them, absence of other certified products. Theoretically, treatment may well be compulsory, but it is difficult to persuade stockbreeders to join the scheme owing to a lack of certainty as to the effectiveness of the products available. Also they (and some Health Defence Groups) are wary of the possible harmful effects of the insecticides.

RECOMMENDATIONS
Human health
The control of vectors and nuisance organisms, particularly in French overseas territories and Corsica, comes up against several problems: definition of strategy and objectives, day-to-day running of operations, resistance to insecticides, low qualification level of field agents, insufficient numbers of team management staff, low level of participation of other partners and populations, insufficient cleansing or public-health related works.
For human health, it is important to:
– Define clearly the objectives and strategies according to the method of governance proposed (public interest groups and regional health agencies).
– Inscribe in this context all decisions that aim to reinforce structures by appointing highly qualified, competent technical managers, assess strategies and actions regularly, involve communities and municipalities.
Animal health
To date, vector control is essentially founded on the administration of insecticides directly onto the animals, with the notable exception of vector control efforts in Reunion Island. This strategy may well be adapted to tick control, but it cannot really be applied against Culicoides and mosquitoes.
For animal health, it is important to:
– Define clearly the objectives and strategies in relation to the DGAL and the veterinary services supervisory bodies.
– Intensify research in order to have available effective control systems against animal diseases, especially emerging ones.

Notes

1 In this chapter, references to the CD-ROM concern question 4: “What are the vector control strategies in France?”.

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