In a major expansion of its policy on Zika virus, the Food and Drug Administration says it now recommends all blood donated in the United States be screened for possible Zika infection.

Blood screening already underway in some areas

"The FDA is updating its guidance after careful consideration of all available scientific evidence, consultation with other public health agencies, and taking into consideration the potential serious health consequences of Zika virus infection to pregnant women and children born to women exposed to Zika virus during pregnancy," the agency said in a statement released today.

In February, the FDA released guidance for areas known to be affected by Zika transmission. Under those recommendations, Florida and Puerto Rico, as well as other areas, began screening blood for Zika contamination, a strategy the FDA says has been effective in identifying infected blood.

"As new scientific and epidemiological information regarding Zika virus has become available, it's clear that additional precautionary measures are necessary," FDA acting chief scientist Luciana Borio said in a statement. "We are issuing revised guidance for immediate implementation in order to help maintain the safety of the U.S. blood supply."

The virus has spread quickly since it was first identified in South America last year. Last month, the first instances of local, mosquito-borne infection in the continental US were reported in Florida. Earlier this month, the CDC instituted a travel advisory for Miami — a possibly unprecedented warning for travel within the United States.

The new FDA recommendations "will be in effect until the risk of transfusion transmission of Zika virus is reduced," the agency said.