Introduction 
The large volume of bird migration in the eastern Mediterranean 
is a well known phenomenon. Studies in disease transmission, particularly 
those caused by arthropod-borne viruses (arboviruses), and the pattern 
of distribution of virus outbreaks and isolations suggested a pattern 
compatible with migratory birds acting as vectors. By 1966, although 
the copious arborvirus literature had documented many instances of wild 
birds, several of which were migratory species, in an active vireraic 
state, there was no published proof that birds were capable of actively 
carrying virus in their blood between continents. Likewise although 
there was ample proof that ticks and other blood-sucking ectoparasites 
were capable of transmitting live virus between vertebrate hosts, there 
was no proof that a migratory bird had carried a tick between continents 
that was capable of infecting other birds with an arbovirus. Most of 
the virus studies had been carried out intensively on either the birds’ 
breeding or wintering grounds in foci of virus activity. It therefore 
remained to investigate birds midway on their migration through an ex¬ 
tensive survey of the birds and their migratory routes, the ectoparasites 
they carried and their blood serology. A combination of factors lead to 
the selection of Egypt as a site of primary concentration. The principal 
investigator, had made intensive ecological and systematic studies of birds 
in the eastern Mediterranean. The United States Naval Medical Research 
Unit 3 (NAMRU-3) in Cairo could provide good logistic and administrative 
support for such work and had scientists actively interested in arbovirology. 
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