"At this point, they're not health concerns", spokesman Robert Yanity said of South Carolina's Zika cases on Friday morning.
"There is still much uncertainty regarding the nature and extent of Zika virus transmission", said Peter Marks, M.D., Ph.D., director of the FDA's Center for Biologics Evaluation and Research.
The current Zika outbreak was first detected in Brazil past year and has since spread across the Americas.
Nationwide, there are 2,517 confirmed cases of Zika virus and about 25 percent are pregnant women. Other units where Zika is suspected are now under investigation, he said.
"With the increase in the number of travel-associated Zika cases in SC and the multiple locations of local transmission in Florida, public concern has grown", he wrote in an email.
Beaufort County's Mosquito Control Program is still awaiting test results to determine whether local insects have Zika.
The tropical mosquito that spreads Zika and other viruses is found along the southern U.S. Friday's directive lists 11 states that will need to begin screening blood in the next month due to their location or because of the influx of travelers from Zika outbreak countries.
"We must implement widespread universal screening now to prevent any further contamination of the blood supply before it occurs and to pre-empt a widespread shortfall in the blood supply", stated Reps.
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Exposure to the Zika virus during the first trimester, including before a woman even realizes she is pregnant, has been linked to a devastating birth defect called microcephaly, in which the infant is born with a small head and underdeveloped brain.
At that time, the agency advised screening blood and blood components for the virus or stopping blood collection completely in areas of active transmission.
The FDA issued its first Zika virus blood screening recommendation in February for areas with active transmission.
One possible complication is that the only blood screening test available for Zika is experimental.
Medic already tests for a number of other viruses, including HIV, hepatitis, Chagas and West Nile.
The agency says all donations must be screened for the disease.
Zika is primarily a mosquito-borne virus that causes no symptoms in 4 out of 5 of those affected.
The recommendation comes after dozens of non-travel related cases of Zika have been identified in Florida. But his sex partner, who hadn't traveled, did get sick with Zika and recovered. While health officials have predicted that mosquitoes in the continental USA would begin spreading Zika this summer, they also have said they expect only isolated clusters of infections and not widespread outbreaks.
