Bluetongue disease vectors (Culicoides spp.): Defining parameters which determine "vector free periods/areas" in Switzerland

• Unité de recherche: OSAV
• Numéro de projet: 1.08.10
• Titre du projet anglais: Bluetongue disease vectors (Culicoides spp.): Defining parameters which determine "vector free periods/areas" in Switzerland

Mots-clé (Anglais)

Bluetongue virus, Culicoides spp., spatial distribution, temporal distribution, climate region, identification, multiplex PCR, breeding habitats.

Description succincte (Anglais)

With bluetongue disease approaching Switzerland, it is essential to know the distribution and seasonal occurrence of the respective insect vectors, Culicoides spp. for which detailed records from only a few locations in Switzerland are available as yet. Light-traps will be operated all year round on suitable farms of 12 locations representing the climate regions of Switzerland. Identification of the very small insects is achieved by microscopy which is a tedious and time-consuming task and by multiplex PCRs which will be developed to simul­taneously identify and quantify in single runs putative vector species of the bluetongue virus. Additional traps will be used to confirm the entomological findings in other locations of the climate regions, for indoor trapping to assess overwintering strategies and for catching Culi­coides spp. in environments with different prevailing hosts (wildlife, domestic animals) to investigate host specificities/preferences among the indigenous midges. Further, their bree­ding habitats will be identified by incubation putative substrates from the field and identifying eclosing midges. Statistical analyses will allow to determine the importance of different parameters on the abundance and diversity of these insects and to draw vector suitability maps on a national scale.

Objectifs du projet (Anglais)

1. Defining parameters which determine a ‘vector free period/area’
In order to be able to identify ‘vector free periods’ and ‘vector free areas’, in terms of BT disease surveillance measures, it is necessary to define the determining parameters. This would include a listing of criteria incorporating geographical, climatic and entomologically derived parameters, the latter based on the placement of insect traps throughout Switzerland in varying altitudes and microhabitats allowing to determine the species diversity and abundance on a national scale. It would also allow to validate a BT model created on a spatial and temporal basis via information collected on vector biology which affects seasonal disease circulation and transmission risks (project 01.05.01).
2. Establishment of standardised Culicoides vector identification
A routine and large scale study of Culicoides needs to develop the capacity to correctly identify and quantify the tiny Culicoides insects to species level also among complex species, which can only be done by molecular techniques. One of these would involve the use of multiplex real-time PCRs which allows to identify several different species in single reactions.
3. Providing Culicoides populations for competency testing
Competency studies on Culicoides potential vector species of Switzerland would be essential for BTV risk assessment. This could be done by experimental infection of local Culicoides populations, either on wild-caught or on laboratory-bred females. During the proposed project, locations will be identified where only single species of Culicoides are occurring yielding ‘specific’ insect populations. It will be attempted to breed several species in the laboratory. Vector competency experiments will be done in a following project in collaboration with the Institute of Virology and Immunoprophylaxis as discussed with its director during a recent meeting.

Mise en oeuvre et application (Allemand)

31.05.2007: Umsetzung:
Erkenntnisse zur Überwachung von Culicoides
Gebiets bezogene Planung von Bekämpfungsmassnahmen
Grundlagen für Anpassungen Technischer Weisungen
neue Methoden zur Differenzierung von Culicoides (Selektionssitzung 2007/mvo)

Mise en oeuvre et application (Anglais)

The results from the study will be directly used to update the legislation concerning BT disease control in Switzerland. The project will provide a quick diagnostic method for Swiss Culicoides spp. and the essential fundamentals for subsequent experimental evaluation of their vector capabilities (in close collaboration with Dr. Griot, Institute of Virology and Immunoprophylaxis, Switzerland). It will also contribute in the global collection of information on the biology of Culicoides, the probably least studied insect vectors in the world. Knowledge on breeding habitats of various species is expected to give clues to options for local control by environmental management.

UMS 2011:
Umsetzungsziel ist erreicht. Ergebnisse beim Festlegen der vektorfreien Perioden eingeflossen.
Im Gespräch ist die Gründung eines Mückenzentrums. GL steht grundsätzlich hinter einem Mückenzentrum, Entscheid dazu ist aber noch ausstehend.
Auftrag ans WissM: Thema aufgreifen für die Verträge mit den Referenzzentren, Gespräche mit Mathis und cwu haben bereits stattgefunden Status: erledigt. Auflagen: erledigt, wenn Publikationen eingetroffen sind

Publications / Résultats (Allemand)

Documents annexés

• Wenk et al revised Vetpar-D-11-4677R1.pdf [PDF] 1'135 kB

Publications / Résultats (Anglais)

Claudia E. Wenk, Christian Kaufmann, Francis Schaffner, Alexander Mathis Molecular characterisation of Swiss Ceratopogonidae (Diptera) and evaluation of real-time PCR assays for the identification of Culicoides biting midges, Veterinary Parasitology

Datenblatt 1.08.10

Kaufmann, C. et al.; (2011) Evaluation of matrix-assisted laser desorption/ionization time of flight mass spectrometry for characterization of Culicoides nubeculosus biting midges. Med. Vet. Entomol. 25: 32-38.

Wenk, C.E. et al.; (2011) Molecular characterisation of Swiss Ceratopogonidae (Diptera) and evaluation of real-time PCR assays for the identification of Culicoides biting midges. Vet. Parasitol. (accepted).

Kaufmann, C. et al.; (2011) Identification of field-caught Culicoides biting midges using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) (submitted).

Steinmann, I. et al.; (2012) Evaluation of matrix-assisted laser desorption/ionization time of flight mass spectrometry for the identification of ceratopogonid and culicid larvae (in preparation).

Kaufmann, C. et al.; Culicoides biting midges: suitability and abundance maps of Switzerland based on 3 years monitoring (in preparation).

Kaufmann et al.; (2012) Parasites Vectors

Steinmann, C.; Pflüger, V.; Schaffner, F.; Mathis, A.; Kaufmann, C.; (2012) Evaluation of matrix-assisted laser desorption/ionization time of flight mass spectrometry for the identification of ceratopogonid and culicid larvae. MALDI-TOF for identification of ceratopogonid larvae, 318-327

Documents annexés

• 1.08.10 Datenblatt MJB 2011, Matthis.pdf [PDF] 15 kB
• Kaufmann et al 2012 Parasites Vectors [PDF] 368 kB
• Kaufmann et al MALDI nubeculosus 2011.pdf [PDF] 713 kB
• Kaufmann et al Parasitology 2012 MALDI.pdf [PDF] 486 kB
• Steimann et al_proof-reading.pdf [PDF] 534 kB
• Wenk et al 2012.pdf [PDF] 479 kB