Swiss drug maker Roche Holding AG ROG, -1.48% said on Monday the U.S. Food and Drug Administration has issued an "emergency use authorization" for the its Zika test in another step to tackle the virus that is spreading across the U.S. "The LightMix Zika test is an easy-to-use molecular diagnostic test that enables healhhcare professionals to quickly detect the virus," said Uwe Oberlaender, Head of Roche molecular diagnostics, in a statement. The FDA on Friday told all U.S. blood banks to start screening for the Zika virus, a major expansion compared to previous guidelines. There have been nearly 2,500 cases of Zika in the U.S. linked to travel to outbreak areas and about 40 cases caused by mosquito bites in Florida.