A new study being published by the U.S. Centers for Disease Control confirms what public health officials around the globe have been fearing: The Zika virus is the cause of a hefty spike in cases of microcephaly, or deformed skull and brains, in babies born to infected mothers in Latin America.

FOX's Eben Brown reports:

Zika, which is spreading through Latin America, including Puerto Rico, has been the subject of warnings for much of the year:

(Frieden) "The science now shows what the hundreds of impacted families have suspected all along: Zika virus is causing the tragic increase in microcephaly cases."

Or skull and brain defects in newborns, says Tom Frieden the director of the centers for disease control, they keep a growing list of where pregnant women are cautioned not to travel. They still don't know the extent of the impact:

(Frieden) "For example, the full range of birth defects related to Zika, also the time in pregnancy of greatest risk."

The virus spreads mainly by mosquito but can be transmitted sexually.

In Miami, Eben Brown, FOX News.