Story highlights The recommendation applies "across the board to anyone collecting blood"

Screening donated blood is already underway in Florida and Puerto Rico

(CNN) The Food and Drug Administration has recommended screening the entire US blood supply for the Zika virus, it announced today, noting that screening donated blood is already underway in Florida and Puerto Rico.

The new recommendation applies "across the board to anyone collecting blood," explained Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research. This includes very large blood collection establishments, such as the American Red Cross, and some very small establishments, such as academic centers, he said.

The Red Cross said it will phase in universal testing. Currently, it is conducting Zika tests in five southeastern states and will expand testing to four additional states in the south central and southwestern US over the next two weeks, the organization said in a statement. The Red Cross did not offer details about which states are covered.

Expanded testing should remain in effect until the risk of transmitting the virus through blood transfusions is reduced, the FDA recommended.

"We've come to a critical juncture: the risk to the blood supply combined with the uncertainty about the nature and extent of Zika virus transmission," Marks said. More than 40 cases of mosquito-transmitted infection have been reported in South Florida.

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