Quantifying the wind dispersal of Culicoides species in Greece and Bulgaria

Abstract

Abstract. This paper tests the hypothesis that Culicoides (Diptera: Ceratopogonidae) species can be propagated by wind over long distances. Movement patterns of midges were inferred indirectly from patterns of the spread of bluetongue outbreaks between farms (using outbreak data from 1999-2001 for Greece, Bulgaria and Turkey) and then matched to concurrent wind patterns. The general methodology was to determine wind trajectories to and from each outbreak site based on the horizontal and vertical wind components of the European ReAnalysis-40 (ERA-40) dataset from the European centre for medium-range weather forecast (ECMWF). Forward trajectories (downwind or where the windvectors pointed to) and backward trajectories (upwind or where the wind-vectors originated from) were calculated for each outbreak for the period from one week before to one week after it had been recorded. These wind trajectories were then compared with the general outbreak patterns taking into consideration the different serotypes involved. It was found that the wind trajectories could be matched to the temporal distribution of the outbreak cases. Furthermore, the spread of the infected vector via the calculated wind trajectories was corroborated by molecular evidence. The conclusion is that the methodology presented is appropriate for quantifying the risk of spread of infected Culicoides midges by wind and that this approach could form an important component of a regional early-warning system for bluetongue.

Perspectives on using remotely-sensed imagery in predictive veterinary epidemiology and global early warning systems

“…Its geographical distribution is usually confined to Africa, with two exceptions in Saudi Arabia and Yemen in the year 2000 which clearly demonstrate the potential of the virus to expand and spread to new continents. In the face of climate change, and the experience of other arboviruses, such as bluetongue (Ducheyne et al, 2007) and Chickingunya in Europe or West Nile virus in Europe and America, RVF may well expand its geographical occurrence.…”

Investigation of Diel Activity ofCulicoidesBiting Midges (Diptera: Ceratopogonidae) in the United Kingdom by Using a Vehicle-Mounted Trap

“…Meteorological conditions in particular play a signiÞcant role in determining dispersal rates both indirectly, through modifying the impact of cues involved in processes such as host or mate location, or directly via transport on prevailing winds, a phenomenon for which this genus is well known (Sellers 1980, Mellor et al 2000, Carpenter et al 2009a. Because meteorological conditions are relatively straightforward to monitor remotely (through the use of global recording networks), predictive models based on these relationships are increasingly being used as an epidemiological tool to analyze patterns of BTV spread in northern Europe (Ducheyne et al 2007(Ducheyne et al , 2011Gloster et al 2008;Hendrickx et al 2008;Agren et al 2010;Sanders et al 2010).…”

Mosquitoes and Culicoides biting midges: vector range and the influence of climate change

“…The indications are that increasing international travel, the globalisation of trade and climate change, among other factors, play an important role in the introduction, establishment and spread of arthropod-borne pathogens (2). In some instances, this is facilitated by the dispersal of vectors over long distances (>100 km) by prevailing winds (3).…”