Have you heard of the Zika virus? A baby in Hawaii is the first in America born with it. The mother likely acquired it in Brazil, where there's a new warning out.

FOX's Eben Brown has more:

Doctors in Brazil and the U.S. are advising pregnant women to check with their physician before visiting that country, due to a spike in cases of Zika virus, which is transmitted by mosquito:

(Dr. Peterson) "Officials there have noted a rather significant increase of cases of microcephaly, which means smaller than expected head size, in infants. And many are pointing to an association between microcephaly and Zika virus infection."

Doctor Lyle Peterson with the U.S. Centers for Disease Control. Zika virus is also on the rise in Mexico and Puerto Rico.

This summer's Olympics are in Rio de Janeiro.

In Miami, Eben Brown, FOX News.