Summary
Until recently, the distribution of bluetongue (BT) virus (BTV) in relation to vector distribution, has been between latitudes 40° North and 35° South. Within these limits the disease occurs in parts of America, Asia, Africa and Australia. Although Europe has suffered several BT epizootics, the disease had not become endemic to the region. The situation is changing. BT has recently emerged in some Mediterranean countries of Europe where it had never previously been reported, in particular in Italy, France, as well as in countries in which only sporadic occurrence of the virus had previously been reported, i.e. Spain (late 1950s), Greece and Turkey (late 1970s). It is relevant to underline that some of the recently affected areas in Europe are not situated within the classical latitudes for BT. Furthermore, although they coincided in time, the recent incursions of BT had two separate origins, coming from beyond the eastern and southern boundaries of Europe. The outbreaks of BT of eastern origin commenced at the end of 1998; they were reported in the Greek islands, and then in the summer of 1999, in Turkey and Bulgaria. In 2001, the disease advanced westwards and northwards, reaching central and north-west mainland Greece, and neighbouring Balkan states; serotypes 4, 9 and 16 were incriminated in this epizootic. The outbreaks of southern origin commenced towards the end of 1999. BTV was confirmed in Tunisia and spread to north-eastern Algeria. In the summer of 2000, the virus reached the Italian island of Sardinia, spreading also to Sicily and Calabria (the Italian mainland area closest to Sicily). In October 2000, BT was reported on the French island of Corsica and in the Spanish Balearic island of Menorca from where it spread to another Balearic island, Mallorca. In 2001, BT spread across south-west mainland Italy. Originally only serotype 2 was isolated in the epizootics of North African origin; however, in 2003-2004, BTV-4 appeared in Morocco, Spain and Portugal.

Keywords
Bluetongue, Culicoides, Europe, France, Italy, Mediterranean, Spain, Virus.