US health officials have granted the use of an experimental blood test to screen for Zika virus, an emergency step that will help protect local blood supplies from the mosquito-borne infection.

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The action means US territories with active Zika infections, primarily Puerto Rico, will be able to resume collecting and screening their own blood.

Previously, the island of 3.5 million barred local donations and began importing blood from the US, following recommendations from the US Food and Drug Administration (FDA).

The FDA said that use of the test, from the drug company Roche, could be expanded if the virus spreads to other areas of the US.

Currently, no US states have reported local, mosquito-transmitted Zika cases.

Puerto Rico has 350 confirmed cases of the virus, including 40 pregnant women.