CDC: Puerto Rico may see hundreds of Zika birth defects

FILE - In this Feb. 24, 2016 file photo, workers from the Puerto Rico Health Department and the Centers for Disease Control and Prevention review Zika-related data collected by the island's health department and the CDC in San Juan, Puerto Rico. On Friday, June 17, 2016, Dr. Tom Frieden, the director of the CDC, is warning that dozens or hundreds of babies in Puerto Rico could develop severe birth defects because of the virus, based on how an outbreak is playing out there. (AP Photo/Danica Coto) (Reuters)

NEW YORK – A top U.S. health official is warning that dozens or hundreds of babies in Puerto Rico could develop severe birth defects because of Zika, based on how an outbreak is playing out there.

Screening of blood donations in the island territory has indicated a rapid increase in the spread of the virus. Officials expect infections will increase through the summer.

Consequently, Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, said Friday that dozens or hundreds of births there could be affected.

The island has more than 1,700 Zika cases, including 191 in pregnant women.

The Zika virus — spread mainly by mosquito bites — causes only a mild illness in most people. But infection during pregnancy can cause fetal deaths and potentially devastating birth defects.