Abundance of Rift Valley Fever vectors in Europe and the Mediterranean Basin Ducheyne E., Versteirt V. & Hendrickx G.
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The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Abstract
Outbreaks of RVF often occur linked to periodical abundance peaks of Aedes and Culex species. Abundance data is therefore critical but needs a specific approach. A novel methodology was developed to model spatial abundance patterns for two potential vectors (Aedes vexans and Culex pipiens) of Rift Valley Fever in Europe and the Mediterranean Basin. For those two species, abundance data was extracted from the compiled papers and subdivided into three categories; low, medium and high abundances. Only geocoded records could be used in the modelling approach. The categories were based on a log-transformation where the low class are sites with 1-10 specimen per trap, medium class sites with 10-1000 specimens and high all sites with more than 1000 specimen per trap. Models were created using Random Classification Forests for each of the classes separately and then combined with a maximum value compositing procedure. In a final step, the abundance map was combined with the probability map. Abundance models could only be created for Cx pipiens as detailed abundance data was lacking for Aedes vexans. Although it has some drawbacks, the proposed methodology has proven to be a useful approach when only scattered literature data is available. © 2013 Avia-GIS.