**5. Bluetongue spread in Europe**

Bluetongue is a devastating disease of ruminants, mostly restricted to certain breeds of sheep, particularly fine wool and mutton breeds common in Europe [35] (Table 2). Until 1998, bluetongue has made only sporadic incursions in Europe, until six strains of the blue‐ tongue virus (BTV), from the Middle East, were transferred to Europe, through two main pathways. One spread northward involving Greece and Balkans. The second one interested the North Africa, and from Tunisia/Algeria landed to Sardinia, Sicily, Corsica, and Balearic islands. Clearly, these pathways are coincident with the traditional livestock trade routes, such ruminant street. The same routes were used in the last years by human migrants to reach the Italian peninsula, i.e., across the Adriatic Sea from Albania and across the Sicily channel from North Africa [36, 37].


**Table 2.** Chronology of blue tongue virus (BTV) spread in Europe

Since its arrival, BTV has caused the deaths of more than one million sheep, and the loss of trade in animals and animal products, with an estimated damage of US\$125 million in the US alone [38]. Sardinia was in particular affected, being the economy largely based on sheep, producing very appreciated like cheese (pecorino) and fine wool. The widespread use of a vaccine, although effective, caused a series of problems for its distribution and episodes of corruption.
