"After several weeks of study and debate, U.S. health officials concluded that infection with the Zika virus during pregnancy causes the birth defect microcephaly, a finding that experts hope will refocus attention on efforts to stop infections and prompt U.S. lawmakers to fund emergency prevention efforts.

"There isn't any doubt that Zika causes microcephaly," Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC), told reporters in a conference on Wednesday.

U.S. and world health officials have been saying for weeks that mounting scientific evidence points to the mosquito-borne virus as the likely cause of the alarming rise in microcephaly in Zika-hit areas of Brazil. It had not been declared as the definitive cause until now."

Julie Steenhuysen and Bill Berkrot report for Reuters April 13, 2016. [2]