Storks on migration over Haifa, Israel. Several individuals of this species were found in this area carrying a particularly virulent form of West Nile Virus from Europe in 1998. David King
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Migratory birds move hundreds to thousands of kilometers twice a year, often spanning continents. As they share certain diseases with people, it is not surprising that birds are frequently blamed for transporting these diseases around the world. But while birds are undoubtedly implicated in the geographic expansion of some emerging diseases, the more interesting question is why it doesn’t happen more often, given the hundreds of millions of birds on the move.