Human and insect travel between continents has resulted in the dissemination of previously
remote infections to more populated parts of the world. West Nile virus apparently moved
from Israel to New York, where it decimated bird populations, and subsequently moved
across the United States, producing human neurologic disease and retinal lesions. Now, a
related virus—Zika virus—has been implicated as the cause of an epidemic of microcephaly,
first in Brazil and now spreading into other parts of the western hemisphere. Zika virus was …