As public health officials hustle to implement strategies to undermine the threat of the Zika virus, a different health concern has come up: maintaining the nation's supply of donated blood.

The Food and Drug Administration is encouraging blood banks to turn away donors who might be at risk due to traveling to a country where the disease is being spread, or having sex with someone who did. Such people should not donate for four weeks. The protocol is being followed by clinics across the country.

"We need to protect the blood supply," said Lawrence Gostin, a professor at Georgetown University and faculty director of its O'Neill Institute for National and Global Health Law. "It would be a major scandal if there were cases of Zika transmitted - particularly if it affected women of childbearing age."

To date, there are more than 800 confirmed cases of the virus reported in the continental United States, almost all connected to traveling abroad. But, though none of those cases was caused by local mosquitoes, experts warn it's only a matter of time.

Though evidence is limited, there's a possibility Zika, which can cause birth defects when contracted by pregnant women and is primarily transmitted by mosquito bites, could also be spread through blood transfusions. That connection, while drawing less attention than links to sex or childbirth, is raising the stakes for what could happen if the virus spreads unchecked in the United States.

Even in locations where Zika isn't likely to pose as great a threat, blood banks are worried that the impact of the FDA's advisory could undercut supplies.

There is no widely available, government-approved blood test to screen donations, though one is being used on an experimental basis for blood collected in Puerto Rico and Houston.

Even though the risk of infection is small, caution is still warranted, experts assert. Unsafe blood has spread dangerous viruses such as HIV. And the consequences of getting Zika - especially for women in the early stages of pregnancy - can include birth defects or miscarriage.

- Kaiser Health News