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FP6

MED_REO_NET Report Summary

Project ID: 44285
Funded under: FP6-POLICIES
Country: France

Final Report Summary - MED_REO_NET (Surveillance network of reoviruses, bluetongue and African horse sickness, in the Mediterranean basin and Europe)

The strategic objectives of the MED_REO_NET project were to further expand our knowledge of the epidemiology of bluetongue, African horse sickness and epizootic haemorrhagic disease in the Mediterranean Basin and Europe and to apply this knowledge to optimise the surveillance of these Culicoides-borne diseases.

The research objectives of MED_REO_NET were to further study the ecology of Culicoides vectors and their expansion and to further study the behaviour of bluetongue and epizootic haemorrhagic disease after their emergence in the Mediterranean basin and in the North of Europe.

Bluetongue virus (BTV) and African horse sickness virus (AHSV) are reoviruses transmitted by vectors species belonging to the Culicoides genus that affect respectively ruminants and Equidae.

Since 1998, large BT outbreaks affected different countries around the Mediterranean basin. The virus has extended further north than ever linked to the northern extension of the main afro-tropical BT vector C. imicola. During summer 2006, BT outbreaks due to a new serotype, serotype 8 were recorded in Belgium, Germany, the Netherlands and France with European Culicoides species probably involved in this emergence. This episode highlighted the potential of BT to further establish in Europe and presents a major risk to the livestock industry. Several other serotypes coming from Eastern Europe (mainly Israel) such as serotypes 5, 15 (outbreaks in 2009) and serotype 24 (outbreaks in 2009 and 2010) are a threat for Europe since only serotype specific vaccines are available (please see http://www.reoviridae.org/dsRNA_virus_proteins/ReoID online). The importance of implementing surveillance networks has to be noted in the way it helps the countries to detect bluetongue occurrence even if the clinical signs were moderate or even absent for some newly detected serotypes.

The coordination action gathered and shared information on BT, AHS and EHD and aimed to:
(i) promote regional studies on the risks of introduction of new strains and spread with inclusion of neighbouring areas (North Africa, Turkey) as an early warning. It is intended to strengthen the surveillance of these three Culicoides-borne diseases by providing a framework for interactions between research institutions and national veterinary services;
(ii) survey the expansion of C. imicola in new northern territories taking into account the potential novel vectors group in Europe; and
(iii) improve information technology for storage, communication and sharing of vector and sentinel surveillance and vaccination data.
The consortium is bringing together national and international reference laboratories working on vectors, detection of infection, and surveillance and risk assessment around Mediterranean.

The following Work packages (WPs) were allocated:

WP-1: Regional surveillance of virus activity and vaccination
The strengthening and harmonisation of surveillance of BT and AHS infection in Europe was pursued by evaluating the following three different components:
1) surveillance protocols;
2) available tools for surveys and strain identification; and
3) vaccination strategies.
It has been decided to take advantage of the EUBTNet system and obtain from EUBTNet the surveillance data required. Data in the EUBTNet system are the official information available from the Member States, therefore the use of EUBTNet data guarantees the consistency with the official situation of member countries. Vaccination data (aggregated data on the basis of administrative units) were not available for any European Union Member States. Data on BT vaccination campaigns are available in form of published data, reports and in scientific literature only in relation to the first years of the BT epidemic and refer to the use of live attenuated vaccines in southern European countries. These data and the results of vaccination campaigns and therefore, cannot be properly extrapolated to the inactivated vaccines now in use.

WP2- Regional surveillance of vectors
This WP has been divided in several distinct deliverables:

1. Recommendation of the optimal trap design for sampling Culicoides
In order to facilitate comparison of data, the efficiency of four suction light traps (the Onderstepoort, Rieb, mini- CDC, Pirbright light traps, BG-sentinel) used at present and in the past in different countries in Europe for the collection of Culicoides midges were compared under field conditions and under different climatic conditions and midge densities in South Africa and Spain, Germany and France. If a large population of Culicoides is necessary to be captured (i.e. virus detection; vector competence; insecticide testing), then the Onderstepoort trap is recommended to be used. Further, the BG Sentinel trap is recommended, because the draught back fan does not affect the captures. The Onderstepoort, the MiniCDC and the BG Sentinel traps could be recommended for seasonal monitoring of Culicoides populations in Europe.

The impact of inside / outside stabling and insecticide has been tested: stabling could be recommended when a clear decrease of catches inside stables is registered when compared with outside catches.

A multicentre evaluation of insecticides was proposed to compare sensibilities of population (C. imicola, C. obsoletus and C. scoticus) to deltamethrin at different concentrations on other species.

2. Guide to the identification of Culicoides vectors and potential vectors present in the Mediterranean (European) basin, including molecular methods and taxonomy
Correct identification of the 1254 Culicoides species is essential for the understanding of disease epidemiology, particularly because few species are recognised as vectors. Several molecular identification assays based on ITS-1, ITS-2 or CO1 were evaluated through inter-laboratory ring trials for the most abundant Palaearctic species usually included in a taxa named 'the Obsoletus complex' (Carpenter et al., 2006). Preliminary Culicoides barcode sequencing a general procedure has been started (please see http://www.barcoding.si.edu/protocols.html online).

A web based morphological key for identification of Culicoides of the Palaearctic region has been developed by B. Mathieu and is available online facilitating the identification of the Palaearctic species and reduce wrong identifications and synonymies.

3. Relationship between Culicoides vector density and BT and AHS, evaluation of the role played in Europe by novel (non- C. imicola) vector species
Modelling of risk in relation with Culicoides distribution and climatic variables has been investigated at a European level with analysis of spatial variability of Culicoides abundance. A complete review of the status of vectors has been carried out based on the published works.

4. Standardised protocols for detection of presence / absence and estimation of abundance of Culicoides, available models of suitable vector (larval and adult) habitat
An analysis of trapping effort and probability of Culicoides occurrence has been conducted. It would be recommended to trap four nights to know with confidence the presence / absence of all Culicoides species in a certain area at a certain period.

A review of the Culicoides breeding sites at Europe level has been carried out. The breeding sites associate to farm level has been investigated for key species such as Culicoides imicola.

The use of a common protocol for studying breeding sites would be recommended (i.e. the use of emergence traps, methods of larvae extraction, etc.).

5. Recommendations on optimal surveillance protocols for Culicoides, reference collection of specimens of C. imicola and obsoletus / pulicaris groups for future DNA analysis and phylogeography
The current sampling grid (usually 50 x 50 km) used in Europe is adequate for the surveillance of Culicoides species in Europe. An ecological stratified sampling remains a valid alternative. There is an optimal knowledge of the seasonality of the major vector Culicoides species in Europe.

For the first time, there has been a harmonisation of the morphology and molecular tools used for Culicoides identification across the countries participating in the MEDREONET project: a list of European and North African Culicoides species has been compiled and will be published soon.

WP3- Molecular epidemiology
In total, over 100 BTV strains from around the world, as references have been sequenced to help identify reassortment events. Sequences can be viewed on http://www.reoviridae.org/dsRNA_virus_proteins/ReoID/BTV-isolates.htm with the development of serotype specific primers for each strain (Maan et al., 2007 and 2010).

WP4- Database, web design and GIS

WP5- Risk assessment
The on-line updating system has been implemented in all the web-GIS services developed: BT outbreaks, BT entomological surveillance, AHS outbreaks, EHD outbreaks.

The field studies, based on the standardised guidelines designed on the previous meeting have been conducted in Bulgaria, Turkey and Algeria. Different risk analysis models have been built, to determine the risk of overwintering and introduction of bluetongue virus. The results of the models determine the factors that have more importance in the maintenance / introduction of the virus and in consequence the sub populations where surveillance can be more sensible to detect the infection (Napp et al., 2010)

WP6- Meetings and dissemination
Annual meetings have been organised in different places hosted by several partners in Palma de Majorca by the University of Balearic Islands, Spain, 12-14 December 2007, in Giulianova, Teramo by IZS, Teramo, 10-11 December 2008, in Lisboa, Portugal, 2-4 December 2009.

For dissemination, a specific booklet on bluetongue, in French has been designed. Those interested can ask for more at the CIRAD editions. The proceedings from the second and third annual meetings will be compiled in a review named Revue elevage médecine vétérinaire (ISSN 1951-6711) edited by CIRAD, in a special issue Volume 2-4, 2009. A poster has been presented to the global conference on agricultural research for development (please see http://www.agropolis.fr/actualites/gcard-2010.php online), 28-31 March 2010. Four newsletters have been done: newsletter 1 in May 2007 and newsletter 2 in November 2007, newsletter 3 in January 2009, newsletter 4 in March 2009.

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