Journals

A successful, sustainable and low cost control-programme for bovine hypodermosis in France

Description
A successful, sustainable and low cost control-programme for bovine hypodermosis in France
Categories
Published
of 11
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Related Documents
Share
Transcript
  This article appeared in a journal published by Elsevier. The attachedcopy is furnished to the author for internal non-commercial researchand education use, including for instruction at the authors institutionand sharing with colleagues.Other uses, including reproduction and distribution, or selling orlicensing copies, or posting to personal, institutional or third partywebsites are prohibited.In most cases authors are permitted to post their version of thearticle (e.g. in Word or Tex form) to their personal website orinstitutional repository. Authors requiring further informationregarding Elsevier’s archiving and manuscript policies areencouraged to visit:http://www.elsevier.com/copyright  Author's personal copy Review A successful, sustainable and low cost control-programmefor bovine hypodermosis in France Chantal Boulard a, *, Michel Argente´  b , Gerard Argente´  c ,Jerome Languille d , Laure Paget e , Etienne Petit f  a  Laboratory of Parasitic Diseases, Immunopathology INRA, IASP, 213, 37380 Nouzilly, France b  Laboratory of Pharmacology, INRA 180 Chemin de Tournefeuille, 31931 Toulouse, France c  Animal Health Farmers’ Organisation (GDS 22), Zoopole, 22440 Ploufragan, France d  Ministery of Agriculture (DGAL), 251 Rue de Vaugirard, 75732 Paris Cedex 15, France e  National Federation of Animal Health Farmers’ Organisation (FNGDS), MNE 149 Rue de Bercy,75595 Paris Cedex 12, France f   Regional Federation of Animal Heath Farmers’ Organisation (F.R.G.D.S Bourgogne),21000 Dijon, France Received 7 March 2008; received in revised form 20 July 2008; accepted 25 July 2008 Abstract Bovine hypodermosis affecting livestock performance and the leather industry was still widespread in France up to the ninetiesdespite successive directives from the Ministry of Agriculture since 1941, encouraging livestock owners to treat, on a voluntarybasis. In 1969 the French Ministry of Agriculture, asked the national Farmers’ Animal Health Organisation (FAHO), to plan adurable hypodermosis control programme and a working group including all the partners in cattle production was set up, under thecoordination of the national FAHO. Improved systems of hypodermosis control, including new treatment and surveillance methodswere developed. Among the main benefits obtained from this srcinal work, were (i) the identification of scientific data whichallowed inexpensive and accurate immuno-surveillance procedures, and a highly effective low-cost treatment, Ivomec 1 ,administered at the micro dose rate (2 m g/kg), which is environmentally non-threatening, and (ii) the development of a newstrategyto manage the controlprogrammes progressively,on aregionalbasis,in twoto threeconcentric zones overthreesuccessiveyears at a maximum. The current programme, coordinated at the National level since 1998, has been implemented in each region of France. The compulsory systemic winter treatments directed against the endo-parasitic stage, carried out by technicians andveterinarians involved the entire bovine population in controlled zones. As each zone reached a hypodermosis herd prevalence of under 5%, usually after two years, the treatments were suspended. However treatments of the infected farms and contiguous farmswere maintained. An immuno-survey was carried out, each winter, to evaluate the prevalence of the disease and detect any residualfoci or re-infestations. Since 2002, bovine hypodermosis in France is under control with immuno-surveillance maintained at a verylow cost. In 2006 hypodermosis became a notifiable disease. # 2008 Elsevier B.V. All rights reserved. Keywords:  Hypodermosis; Myiasis; Control scheme;  Hypoderma  spp; Bovine; Francewww.elsevier.com/locate/vetpar  Available online at www.sciencedirect.com Veterinary Parasitology 158 (2008) 1–10* Corresponding author. Tel.: +33 6 27362516. E-mail address:  cboulard@voila.fr (C. Boulard).0304-4017/$ – see front matter # 2008 Elsevier B.V. All rights reserved.doi:10.1016/j.vetpar.2008.07.026  Author's personal copy Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22. Elaboration of the current French hypodermosis control programme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1. Management of the treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1.1. Preliminary assays on a communal and a departmental basis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1.2. Pilot scheme on a regional basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.2. Improvements of hypodermosis diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.3. Evaluation and development of alternative therapeutic tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63. The national directives of the current French programme leading to a durable control of hypodermosis. . . . . . . . . . 73.1. The essential measures to be taken at a regional level are: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.2. The present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction Bovine hypodermosis is still widely distributed allovertheNorthernhemispherefromEasternandSouthernEurope (O’Brien, 1998) to Eastern China (Yin et al., 2003), and in North America (Scholl, 1998). It is caused by the development of the larval stages of insectsinducing myiasis (Diptera, Oestridae), belonging to thegenus  Hypoderma  (  H  .). Two species are generallyinvolved in bovine hypodermosis (  H. lineatum  and  H.bovis ),  H.sinense isalsoencounteredinChina(Yinetal.,2003). They are strictly parasites of all the  Bos  genusspecies but may infect humans accidentally. Theseparasites have an annual synchronised biological cycle.The first endo-parasitic stage migrates in the deepconnective tissues of their hosts, from summer to thefollowing spring. In spring, the larvae reach the dorsalsubcutaneous tissue of their hosts and moult into thesecondandthethirdlarvalstages,producingswellingsonthe skin along the back, called warbles. Thematurethirdstages fall on the ground and pupate at the end of spring.After one month the adult stages emerge. These fliesunable tofeed have a shortlife ofoneweek.They spreadthe disease, within a radius of 5 km, by laying their eggson the hair of the cattle.The larvae induce hypodermosis, a serious cattledisease (Tarry, 1998), affecting weight gain, welfare,bovine immune defence mechanisms (Boulard, 1989;Nicolas-Gaulardetal.,1995)andtheleatherindustry.Inconsequence, many attempts to control these parasiteshave been made following different approaches. Thecontrol measures were generally directed towards thelarvae, but also in one case against the adults. A jointUS-Canadapilotcattlegrubprojectwascarriedoutforaperiod of four years (1982–1986) in a territorycontaining 72,000 bovines. This programme was basedon the principle of massive releases of sterile flies of   Hypoderma spp.intonaturalpopulations.Suchmethodshad proved successful in the eradication of thescrewworm, but the project failed to control hypoder-mosis in North America (Kunz et al., 1990). The mainlimiting factor was the absence of reliable techniquesfor mass production  in vitro , of   Hypoderma  flies forsterilization.So far, definitive hypodermosis control has beenachieved only in Western European countries. The firstexample of bovine hypodermosis eradication occurred,one hundred years ago, in the Danish islands withoutany therapeutic agents. The farmers eliminated the pestwith success, by a manual extraction, of all the grubsfrom the warbles of their cattle and it was maintained ahypodermosis-free territory for a few years (Boulard,2002). This example demonstrates that definitivecontrol of hypodermosis is strictly dependent onorganisation and management.Later successful control programmes have all beenbased on chemical control directed against the larvae of the first stage, the most sensitive to insecticides, using asingle annual systemic drug administered in winter,when the cattle are housed. These programmes havebeen successful, whatever the molecule used (organo-phosphorus (OP) compounds or macrocyclic lactones)(Boulard, 2002).The successes and the failures of each of thesehypodermosis control programmes including thosewhich finally succeeded, were examined by theEuropean specialists on hypodermosis, between 1992to 2002, in the framework of two European Cost(European cooperation in the field of scientific andtechnical research) actions (811 and 833).The main success’ factors for hypodermosis controlwhich were identified were: (i) the awareness of the C. Boulard et al./Veterinary Parasitology 158 (2008) 1 – 10 2  Author's personal copy stockowners of the economic effects of hypodermosisandthecost/benefitofacontrolprogramme,(ii)theneedfor a political commitment and the introduction of specific legislation for bovine hypodermosis, (iii) theorganisationineachcountryofacoordinated,largescale,controlscheme atnationallevel, making compulsory thetreatmentofallcattle,(iv)themaintenanceofwarblefreestatus, involving sensitive tools for hypodermosissurveillance and detection (Boulard, 2002).Among the hypodermosis free European countries,France was the last one to reach this status. Up to thenineties, after successive attempts at hypodermosiscontrol (Boulard, 2002), the overall results remainedpoor and the warbled herd prevalence stayed as high as50% in some regions.However, in 1969, the French Ministry of Agricul-ture, greatly concerned over this disease, invited thenational Farmers’ Animal Health Organisations(FAHO) to become involved in the coordination of research into improving the methods required for anefficient management of the ongoing programmes. InFrance, twenty millions cattle (both beef and dairycattle) needed to be treated simultaneously, all over thecountry. Under such a large project, the drugs availableon the market were not satisfactory in terms of risks of environmental pollution, residues in milk, and financialcost. It was recognised that srcinal solutions should beprovided, taking into account the protection of theenvironment and the consumers and the cost of suchprogramme. A working group was created, bringingtogether the national FAHO, the Veterinary Services(VS), the Veterinary Practitioners Organisation (VPO),the leather industry and the scientific community of theMinistry of Agriculture (INRA). Through sharing theirexperience and understanding of this disease, they builtup,stepbystep,thebasisofanewmanagement regimento achieve sustainable and durable results. 2. Elaboration of the current Frenchhypodermosis control programme 2.1. Management of the treatments2.1.1. Preliminary assays on a communal and adepartmental basis One of the primary factors in the success demon-strated by the Irish and British hypodermosis controlprogrammes in the seventies was the compulsorytreatment, of the entire cattle population, in the regionsinvolved in the programme.In France, the first law aimed at stimulatinghypodermosis control was introduced in 1941, makingthe treatment of warbled cattle compulsory. But thetreatments were carried out on a voluntary basis byfarmers and a survey carried out forty years laterindicated that less than 1% of the 23 million cattle weretreated against hypodermosis (Boulard et al., 1984).Therefore the first task of the French working grouponhypodermosis wastoconvincethe farmerstotreatallcattle and to demonstrate how this would be done, whena hypodermosis control campaign started. In 1978, apreliminary demonstration pilot schemewas carried outinthe32dairyherds ofavillageinBretagne. Afterthreeyears of a winter treatment regimen by the departmentalFAHO technicians, it was demonstrated that hypoder-mosis could be totally controlled and winter treatmentswere suspended in that village. All the herds werewarblefree; however,surrounding infested herds spreadthe disease back again in the two following years.This preliminary assay in Bretagne, was thenenlarged by the departmental FAHO, to all the13,300 herds of the department’s (637,000 cattle with85% of dairy cows). At the beginning of the campaign,the hypodermosis prevalence varied from 16.5% of warbled herds, in an area close to the sea to 66% in thearea close to the untreated surrounding departments.Five concentric zones were defined; the first oneparticipating in this programme was by the sea. Thenyear after year the surrounding zones were integratedinto this programme. The compulsory winter treatmentswere administered by the local veterinary practitionersor by the FAHO technicians. Warble prevalence surveyswere performed in spring by the technicians on 20% of the farms, with monthly observation and control (whennecessary), during the three months of the warblesemergence period. When the infestation rate decreasedbelow 5% warbled herds, usually after two annualgeneralised treatments per zone, the winter treatmentswere suspended. In the farms still found warbled inspring a ‘‘tactical treatment’’ was implemented the nextautumn to include all surrounding herds within 5 km,corresponding to the limit of the area where the adultsfly (Argente´ and Boulard, 1986).Nevertheless, in 1990, the average rate of infestationstill remained at 3.6% infested herds, on the depart-mental borders. As the disease spread rapidly from farmto farm, a regional approach to control hypodermosis inBretagne (a peninsula) was then considered as anecessary factor, to reach a durable success and sowas launched the following year. 2.1.2. Pilot scheme on a regional basis The preliminary results, obtained in Bretagne, hadstimulated other regional FAHO members and in 1988, C. Boulard et al./Veterinary Parasitology 158 (2008) 1 – 10  3  Author's personal copy an organised pilot project was conducted by the FAHO-Bourgogne,onaregionalbasis.Thefourdepartmentsof Bourgogne, unlike Bretagne, have a continentalsituation. More than one million two hundred thousandcattle, mainly beef cattle are bred there (Petit, 1993).Prior to this pilot scheme, the evaluation of thewarbled animal prevalence carried out once in March1988, by clinical examination, indicated that 30% of theexamined farms were warbled. The same year, animmuno-serological survey indicated that 99% of theherds were sero-positive, confirming the discrepancybetween the two methods of hypodermosis diagnosisobservedin all field assays (Vaillant etal., 1997)and thenecessity to have reliable tools to detect the infestedfarms (see Section 2.2).This regional pilot control programme, underFAHO-Bourgogne’ coordination, was started withlegislative support insured by a ‘‘prefectorial’’ decree.The Bourgogne territory was divided into fourconcentric zones, with 100,000 cattle in the centralterritory, 240,000 cattle in the second zone. The thirdhad 830,000 cattle and the last 100,000 (Fig. 1).A progressive implementation of the hypodermosiswinter treatments was introduced in each of the fourconcentric territories, in successive years (Fig. 1).Different drugs were used, including micro doses of Ivomec (see Section 2.3), which presented the highestefficacy and the lowest cost (Bland, 1990).Theevaluationofthisprogramme,duringthefirstfouryears, was made by warble detection carried out once inspring by the FAHO technicians on 20% of the herds.One warble, on one animal, in one herd was enoughto make this herd positive. The prevalence was thenexpressed in percentages of infested herds. In 1992, ahypodermosis immuno-survey was introduced, carriedout on the sera collected in winter for the on-goingbrucellosis survey (Petit, 1993). Such sera sampling fora hypodermosis survey, was already in place all over thecountry in UK (Webster et al., 1997).After two years, the herd prevalence of the treatedterritories fell below 5% warbled herds. This was theempirical threshold chosen to end generalised treatmentand to restrict the ‘‘winter tactical treatments’’ to thewarbled herds of the previous spring.The prevalence of the sero-positive herds, comparedto the warbled herds, after only one clinical examina-tion, appeared to be 3–10 times higher (Fig. 2).Thisexperimental control programmewas continuedin Bourgogne the following years. The generalisedtreatments had stopped but surveillance was main-tained, as well the ‘‘tactical treatments’’ for warbledherds.It is important to note that severe side effectsassociated with the winter treatments (Boulard, 1979;Eyre et al., 1981) in this highly infested territory,affected 0.8%ofthetreatedcattle thefirst year.Withthedramatic decrease of the prevalence of the disease aftertwo years, these side effects also fell for the all region to0.2% and then disappeared. The costs of all theincidents and accidents were reimbursed by the FAHO.Until the implementation of a national controlprogramme for hypodermosis in 1998, a low level of infestation remained along the borders of Bourgogneandthisfellclosetozeroaftertheimplementationofthecountrywidecontrol programme(Fig.2).Theverylow-sero-prevalence in herds which decreases every year, is C. Boulard et al./Veterinary Parasitology 158 (2008) 1 – 10 4Fig. 1. Schedule’ implementation of the hypodermosis control programme in Bourgogne and number of treated animals in each zone.

Clã Daeva

Apr 22, 2018
Search
Tags
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks