A first estimation of Culicoides imicola and Culicoides obsoletus/Culicoides scoticus seasonality and abundance in Europe

Abstract

Culicoides imicola and C. obsoletus/C. scoticus are considered important vectors in Europe for the transmission of bluetongue and Schmallenberg virus. The seasonality and abundance of C. imicola and C. obsoletus/C. scoticus was assessed in Europe based on literature, expert input and modelling techniques detecting the onset and end of the vector season. Culicoides obsoletus/C. scoticus has a large distribution across Europe and can often be found in high abundances. The abundance peak is driven by temperature and humidity and is reached late spring/early summer and fall. The species is sometimes found as adult overwintering in stables but numbers are rather low; this can however have implications for the overwintering of the bluetongue virus. Culicoides imicola is restricted to countries around the Mediterranean basin and the predicted abundance is lower and the species appears only later in spring with a peak in fall.

Modelling the monthly abundance of Culicoides biting midges in nine European countries using Random Forests machine learning

“…Versteirt et al [20] presented an abundance map for C. obsoletus/C. scoticus in Europe made by Balenghien & Wint [20]. The spatial pattern shown in our maps is relatively similar, although differences appear in their findings of the highest abundance in western France, in contrast to our results of high abundance in Germany.…”

“…Our model identified areas with the highest abundance of the Obsoletus ensemble in Germany, followed by France. Versteirt et al [20] presented an abundance map for C. obsoletus/C. scoticus in Europe made by Balenghien & Wint [20].…”

“…The spatial pattern shown in our maps is relatively similar, although differences appear in their findings of the highest abundance in western France, in contrast to our results of high abundance in Germany. It is important to take into consideration that the maps presented by Balenghien & Wint [20] were made using two species from the Obsoletus group, while we used species from the Obsoletus ensemble to model and map the spatial abundance. The differences found between our results and theirs might result from the differently grouped species that were used to produce the maps.…”

“…Using entomological data collected on farms and environmental variables obtained from satellite imagery, it is possible to model and map the abundance of vectors. Culicoides abundance maps for Europe can be found either at a national [15][16][17] or a continental scale for C. imicola [18,19] and for the Obsoletus ensemble [20]. The Culicoides maps available at a continental scale for Europe are usually created with abundance data collected within a limited area of the mapped region.…”

Bluetongue: control, surveillance and safe movement of animals

“…those taking place in the southern Europe) allows a longer seasonal activity of adults. In addition, fauna of Culicoides from southern and northern Europe differs in some of the major species, such as C. imicola which is not present in northern Europe (Versteirt et al, ).…”